Improve dewatering of biomass

Scout intake sheet

5
Challenge description

The Netherlands produces a great variety of heterogenic biobased waste streams (biomass) without creating value out of these streams. The current way of processing these streams results in unnecessary CO~2~ emissions, loss of valuable materials and economic value. Next to water and contaminants, biomass contains organic matter that could be turned into valuable ingredients. BCB is on the outlook for technologies that can convert biomass into valuable materials or energy. Besides being diverse and heterogenic, biomass often contains a large amount of water. The high water content makes transportation of biomass both from an economic and sustainable point of view unattractive. Moreover, the low percentage of dry material could impair the conversion of biomass to valuable output materials or even make it impossible. Dewatering of biomass is therefore a known pre-treatment option before conversion. For some types of biomass, for example biological sludge, dewatering is not an easy process though. The cellular structures need to be degraded in order to remove water. This project provides an overview of dewatering technologies for all sorts of biomass varieties. BCB is especially interested in innovative (combinations of) mechanical/physical technologies that improve the dewatering process. Chemical technologies are only interesting when they improve the efficiency of a mechanical method. Ideally the methods are mild technologies, that preserve the functionality of the organic matter. Furthermore, technologies that consume a relatively low amount of energy are most relevant.

Scope
Discover Demonstrate Develop Deploy
Current known technique(s)
  • Centrifugation
  • Filtration
  • Ultrasound
  • Pressing
  • Thermal treatments
Ideal outcome

A list of technologies that improve the dewatering process of biomass, including not widely known technologies that have a relevant TRL level. 

Minimum viable outcome

An overview of methods to dewater biomass.

Objective(s)
  • Scalability
  • Capacity
  • Centralized/Decentralized
  • Requirements for conversion
  • Type of biomass
Constraint(s)
  • Added value (how much extra water removed)
  • Technology readiness level
  • Efficiency (e.g.% dry content and organic material loss)
  • Energy consumption
  • End product % dry matter/water
Functions
Action = [improve] OR [dewater]

Object = [dewatering] OR [biomass]

Environment = [biomass] OR [efficient]
Terminology
  • dewater
  • biomass
  • drain(age)
  • sludge
  • manure
  • solid-liquid separation
  • mild
Case Confirmation
Confirmed by
Comments

Preliminary Results

Published 06/11/2020

Based on the case described above we have executed the first line of queries in IGOR^AI. The goal was to obtain a broad set of technologies that dewater biomass. 7 concepts are distinguished based on the results: 1. Filtration 2. Force and/or temperature based approaches 3. Electrokinetics 4. Radiation 5. Biological approaches 6. Combinations 7. Extra: chemical treatments Every concept comprises multiple technologies (44 in total). Below the table, short descriptions, research findings and sources per technology are listed as well. You can use this information to get a better understanding of the technologies. During the midway meeting, we would like to discuss the technologies and concepts, determine their relevance and select the top selection that needs to be deepened in the second phase of the project.

To determine which technologies are relevant to proceed to the next scouting phase you can play the technology selection game by clicking on the button below.

Concept Technology Selection
1. Filtration
Dewatering methods based on filtration.
1.1 Filter press

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1.2 Thermal compression

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1.3 Hydraulic compression

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1.4 Belt filter press

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1.5 Rotary press

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1.6 Vacuum filtration

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1.7 Vibration screen

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1.8 Geotextile tube

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1.9 Tangential flow filtration

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1.10 Screw press

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1.11 Magnetic filtration

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1.12 Osmotic separation

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1.13 Other filtration technologies

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2. Force and/or temperature based approaches
Dewatering methods based on force and/or temperature without filtration. 
2.1 Centrifugation

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2.2 Freeze thaw

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2.3 Flotation methods

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2.4 Fluidized bed

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3. Electrokinetics
Electrohydrodynamics (EHD), also known as electro-fluid-dynamics (EFD) or electrokinetics, is the study of the dynamics of electrically charged fluids. [\[link\]](https://en.wikipedia.org/wiki/Electrohydrodynamics)
3.1 Electro-dewatering

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3.2 Electroflotation

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3.3 Electrocoagulation/electroflocculation

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4. Radiation
Radiation is the emission or transmission of energy in the form of waves or particles through space or through a material medium. [\[link\]](https://en.wikipedia.org/wiki/Radiation#:\~:text=In%20physics%2C%20radiation%20is%20the,%2C%20and%20gamma%20radiation%20(%CE%B3))
4.1 Ultrasonication

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4.2 Electron irradiation

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4.3 Gamma radiation

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5. Biological approaches
Dewatering methods using biological components. 
5.1 Reed beds

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5.2 Bioleaching

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6. Combinations
Combinations of mechanical methods: two consecutive methods as examples and integraded methods as separate technologies. 
6.1 Electro Acoustic Dewatering press (EAD press)

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6.2 Electro-coagulation floatation (ECF)

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6.3 Centrifugation + filter press

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6.4 Flotation + filtration

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6.5 Flotation + centrifugation

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6.6 Screw press + vibration screen

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6.7 Freeze thaw + agitation

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6.8 Electrocoagulation + electro-dewatering

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6.9 Magnetic conditioning + electro-dewatering

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7. Extra: chemical treatments
Out of scope and incomplete, but added here as additional information on (conditioning) methods to dewater biomass.
7.1 Coagulation

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7.2 Flocculation

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7.3 Gel extraction

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7.4 Fenton's reagent

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7.5 Polyelectrolyte

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7.6 Alum sludge

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7.7 Fly-ash

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7.8 Dimethyl ether

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1. Filtration

Back

Dewatering methods based on filtration.


1.1 Filter press

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An industrial filter press is a tool used in separation processes, specifically to separate solids and liquids. The process uses the principle of pressure drive, as provided by a slurry pump. [\[link\]](https://en.wikipedia.org/wiki/Filter_press) **Note:** thermal treatments combined with filter press are included here. **Highlights:** * **Thermal filter press dewatering equipment** composed of squeezing plate and a fixed heating plate was developed to **improve the dewaterability of pigment the sludge** as supplying the heat from the fixed heating plate to the cake. \[...\] In this research, it was resulted that the squeezing process and long dewatering time were effective to improve the dewaterability of pigment sludge. So, this thermal filter press equipment was useful for dewatering the fine particle sludge like pigment. [\[Art. #ARTNUM\]](#article-96002-267445013) * A new conditioning process made up of an acidic oxidative pre-conditioning step that is based on the **Fenton reagent** (essentially H 2 O 2 and FeCl 2 ) and followed by a corresponding inorganic post-conditioning step with **calcium hydrate** is presented. By means of this new conditioning process, even **undigested biological waste tratement sludges are dewatered in membrane filter presses** to a water loading of only 1.0-1.2 H 2 O/kg SDM O (suspended dry matter) with normal filtration/press times. [\[Art. #ARTNUM\]](#article-96002-2067100902) * The effects of **ozone treatment** on the **dewaterability of activated sludge** wasted from a sewage treatment plant were investigated in this study. Following ozone treatment, sludge was dewatered using a **pressure filter.** The sludge filterability evaluated by SRF deteriorated with ozone dosage at relatively low ozone doses. However, at ozone doses higher than 0.6gO3/gSS, the SRF of the ozone treated sludge became comparable with the value for the sludge without ozone treatment. \[...\] In terms of **cake volume, more than 55 % reduction** was obtained at 0.4gO3/gSS. These observations suggest that ozone treatment has potential to significantly enhance sludge dewaterability and to produce a more compact cake without severe deterioration of its filterability. [\[Art. #ARTNUM\]](#article-96002-2274104247) * The raw dam water associated with the prototype unit is clarified using a **polyelectrolyte/bentonite mixture**. The resultant sludge has a mean solids concentration of 23 g/l. The prototype **tubular filter press** has produced on average a cake with a **solids concentration of 32%** mass/mass and a filtrate with a suspended solids of 57 mg/l.[ ](#article-96253-2048552757)[\[Art. #ARTNUM\]](#article-96002-2048552757) * The invention discloses a technology for **improving the dewaterability of excess sludge.** The technology includes the first step of low-temperature **plasma aeration**, the second step of **acidity regulation**, the third step of **fenton-like oxidation** and the fourth step of **plate-frame pressure filtration.** The low-temperature plasma technology is combined with fenton-like oxidation for treatment the excess sludge together, sludge **cell walls are effectively damaged**, and the dewaterability of the sludge is improved. The water content after sludge dewatering is lower than 60%, the salt content is low, the heat value is high, and the technology is suitable for sanitary landfill and incineration and also suitable for aerobic fermentation to prepare biological organic fertilizers.[ \[Art. #ARTNUM\]](#article-96002-2825805534) * A **new sewage sludge semi-drying (dewatering) process** is proposed and verified. It **combines thermal hydrolysis** and subsequent mechanical dewatering, with **less energy consumption** than traditional thermal drying. Sludge treated using this new process satisfies further disposal requirements (e.g., landfill or autothermal incineration). In the present study, a high-pressure test reactor was used to study the thermal hydrolysis of dewatered sludge. Thermally hydrolyzed sludge was subsequently dewatered by centrifugal sedimentation or by **pressure filtration.** [\[Art. #ARTNUM\]](#article-96002-2028845792)

1.1.1 Filter press
[Improvement of municipal sewage sludge dewaterability by bioleaching: a pilot-scale study with sequence batch reaction model].
To observe the bioleaching effect on sewage sludge dewaterability,three consecutive batch bioleaching experiments were conducted through a bioleaching bio-reactor with 700 L of working volume.Subsequently,the bioleached sludge was dewatered by using chamber filter press.The results show that the 1st batch bioleaching process can be finished within 90 hours if the aeration amount was 1.2 m3/h with the 1∶15 mixing ratio of bioleached sludge to raw sludge.The pH of sludge declines from initial 6.11 to 2.33 while ORP increased from initial-134 mV to finial 507 mV.The specific resistance to filtration(SRF) of the tested sludge was decreased from original 1.00×1013m/kg to final 0.09×1013m/kg after bioleaching.For the subsequent two batch trials,the bioleaching process can be finished in 40 hours and 46 hours,respectively.Likewise,sludge SRF is also significantly decreased to 0.19×1013m/kg and 0.36×1013m/kg if the mixing ratio of bioleached sludge to fresh sludge is 1∶1 although the microbial nutrient substance dosage is reduced by 25% and 50% for 2nd and 3rd batch experiments,respectively.The harvested bioleached sludge from three batch trails is dewatered by chamber filter press with 0.3-0.4 MPa working pressure for 2 hours.It is found that the moisture of dewatered sludge cake can be reduced to 58%,and that the dewatered sludge cake is of khaki appearance and didn't emit any offensive odor.In addition,it is also observes that sludge organic matter only changed a bit from 52.9% to 48.0%,but 58% of sludge-borne Cu and 88% of sludge-borne Zn can be removed from sludge by bioleaching process.Therefore,dual goals for sludge-borne heavy metal removal and sludge dewatering of high efficiency can be achieved simultaneously through the approach mentioned above.Therefore,bioleaching technique is of great engineering application for the treatment of sewage sludge.
07/01/2011 00:00:00
Link to Article
1.1.2 Filter press
A new conditioning process for the dewatering of wastewater treatment sludge
A new conditioning process made up of an acidic oxidative pre-conditioning step that is based on the Fenton reagent (essentially H 2 O 2 and FeCl 2 ) and followed by a corresponding inorganic post-conditioning step with calcium hydrate is presented. By means of this new conditioning process, even undigested biological waste tratement sludges are dewatered in membrane filter presses to a water loading of only 1.0-1.2 H 2 O/kg SDM O (suspended dry matter) with normal filtration/press times.
08/01/2000 00:00:00
Link to Article
1.1.3 Filter press
A study on the Thermal Filter Press for the Reduction of Pigment Sludge
Dewatering process to remove water from pigment sludge was important in the diverse aspects of the improvement of product quality, curtailment of the drying cost and the transportation. It was difficult to dewater pigment particles with the mechanical forces because the size was fine under . Thermal filter press dewatering equipment composed of squeezing plate and a fixed heating plate was developed to improve the dewaterability of pigment the sludge as supplying the heat from the fixed heating plate to the cake. Several tests that estimate the dewaterability for pigment sludge as with or without squeezing process and the difference of dewatering time was conducted with this equipment. Dewaterability of thermal dewatering under squeezing process was increased about 20% compared with non squeezing process. Under squeezing process, thermal dewatering tests changing dewatering time with 70 and 80 minute were conducted respectively. The water content of cake was more reduced at dewatering time of 80 minute compared with 70 minute, and dewatering velocity was also decreased, which caused the productivity of thermal filter press to drop. It was observed that clogging of filter cloth didn't almost occur because the liquid was discharged from cake layer easily. In this research, it was resulted that the squeezing process and long dewatering time were effective to improve the dewaterability of pigment sludge. So, this thermal filter press equipment was useful for dewatering the fine particle sludge like pigment.
01/01/2009 00:00:00
Link to Article
1.1.4 Filter press
Enhancement of Sludge Dewaterability by Ozone Treatment
The effects of ozone treatment on the dewaterability of activated sludge wasted from a sewage treatment plant were investigated in this study. Following ozone treatment, sludge was dewatered using a pressure filter. The sludge filterability evaluated by SRF deteriorated with ozone dosage at relatively low ozone doses. However, at ozone doses higher than 0.6gO3/gSS, the SRF of the ozone treated sludge became comparable with the value for the sludge without ozone treatment. It is suggested that the oxidation of the viscous, high molecule organics attached at cell surface reduces the surface charge of sludge particle and promotes flocculation at relatively high ozone doses. Ozone treatment also cause the release of bound water trapped inside cells or floes, resulting in significant reduction of cake water content after dewatering. In terms of cake volume, more than 55 % reduction was obtained at 0.4gO3/gSS. These observations suggest that ozone treatment has potential to significantly enhance sludge dewaterability and to produce a more compact cake without severe deterioration of its filterability.
11/01/2001 00:00:00
Link to Article
1.1.5 Filter press
Experimental Study on Thermal Hydrolysis and Dewatering Characteristics of Mechanically Dewatered Sewage Sludge
After mechanical dewatering, sewage sludge has a moisture content of around 80 wt% and further disposal is required. A new sewage sludge semi-drying (dewatering) process is proposed and verified. It combines thermal hydrolysis and subsequent mechanical dewatering, with less energy consumption than traditional thermal drying. Sludge treated using this new process satisfies further disposal requirements (e.g., landfill or autothermal incineration). In the present study, a high-pressure test reactor was used to study the thermal hydrolysis of dewatered sludge. Thermally hydrolyzed sludge was subsequently dewatered by centrifugal sedimentation or by pressure filtration. The amount of organic compounds returning to the water phase was also measured. According to the results from centrifugal settling tests, the optimal thermal hydrolysis treatment temperature was 180°C. The moisture content then dropped to 1.44 kg/kg dry solids (DS; 59 wt%) after dewatering under relative centrifugal force of 9,000 × g from 5.6...
11/01/2011 00:00:00
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1.1.6 Filter press
Hydrothermal and alkaline hydrothermal pretreatments plus anaerobic digestion of sewage sludge for dewatering and biogas production: Bench-scale research and pilot-scale verification
Abstract To test the feasibility and practicability of the process combing hydrothermal pretreatment for dewatering with biogas production for full utilization of sewage sludge, hydrothermal/alkaline hydrothermal pretreatments and in turn anaerobic digestion of the filtrates obtained after dewatering the pretreated sludge were performed at bench- and pilot-scales. The hydrothermal temperature fell within the range of 140 °C–220 °C and the pretreatment time varied from 30 min to 120 min. For the alkaline hydrothermal pretreatment the pH value of the sludge was adjusted to 9.0–11.0 by adding Ca(OH) 2 . The results showed that the dewaterability of the sewage sludge was improved with increasing pretreatment temperature but the impact of the pretreatment time was not significant. The addition of Ca(OH) 2 gave better performance on the subsequent mechanical dewatering of the pretreated sludge compared to pure hydrothermal pretreatment, and the higher the pH value was, the better the dewaterability of the pretreated sludge was. The conditions of 180 °C/30 min and 160 °C/60 min/pH = 10.0 (for hydrothermal and alkaline hydrothermal pretreatments, respectively) resulted in relatively good results in the theoretical energy balance, which were verified in the pilot-scale tests. Based on the data from the pilot tests, the alkaline hydrothermal process realized self-sufficiency in energy at the cost of a proper amount of CaO.
06/01/2017 00:00:00
Link to Article
1.1.7 Filter press
Technology for improving dewaterability of excess sludge
The invention discloses a technology for improving the dewaterability of excess sludge. The technology includes the first step of low-temperature plasma aeration, the second step of acidity regulation, the third step of fenton-like oxidation and the fourth step of plate-frame pressure filtration. The low-temperature plasma technology is combined with fenton-like oxidation for treatment the excess sludge together, sludge cell walls are effectively damaged, and the dewaterability of the sludge is improved. The water content after sludge dewatering is lower than 60%, the salt content is low, the heat value is high, and the technology is suitable for sanitary landfill and incineration and also suitable for aerobic fermentation to prepare biological organic fertilizers.
05/31/2017 00:00:00
Link to Article
1.1.8 Filter press
The dewatering of sludges using a tubular filter press
Abstract A tubular filter press process using fabric tubes has been developed to dewater the sludge resulting from the clarification of raw water. A prototype plant, designed to dewater the sludge resulting from the treatment of 30 Ml/day of surface water, has been constructed by a water authority. The slurry is fed under pressure into an array of porous tubes, the liquid in the slurry filters through the tube walls while the slurry solids are deposited as a thin layer on the internal walls of the tubes. The cake is dislodged periodically from the tube walls and transported hydraulically out of the tubes where it is drained and conveyed to a collection hopper. The raw dam water associated with the prototype unit is clarified using a polyelectrolyte/bentonite mixture. The resultant sludge has a mean solids concentration of 23 g/l. The prototype tubular filter press has produced on average a cake with a solids concentration of 32% mass/mass and a filtrate with a suspended solids of 57 mg/l. The process operates with minimum supervision and no chemical addition. The solids dewatering capacity for a feed solids concentration of 23 g/l and operating at a pressure of 400 kPa is 1.5 kg dry solids/ m2 h. The performance of the unit can be described using standard filtration theory modified for a circular filtration surface. The performance to date indicates that this process compares favourably with other commercially available sludge dewatering methods.
12/01/1987 00:00:00
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1.2 Thermal compression

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The use of temperature and pressure to filter sludge. **Highlights:** * In the present work, sewage **sludge is dewatered by the thermal compression**, which shows unique separation advantages of various materials, and the **effects of applied temperature and pressure on the dewatering performance** are investigated. The **filtrate** SCOD reveals that higher temperature benefits the disruption of sludge flocs, resulting in the release of organic content. According to the accumulative filtrate volume, higher temperature and pressure facilitate the dewatering process, obtaining **sludge cake with lower moisture content.** [\[Art. #ARTNUM\]](#article-96263-2148107480) * In this paper, the use of **thermal compression** to improve the sludge dewatering is investigated. The **dewatering** efficiency is affected by the **applied temperature, pressure and the sludge mass.** The bound water of the sludge is further reduced by thermal compression, improving the dewatering performance. The **solid content** of the cake obtained after 10 min mechanical compression and 60 min thermal compression at 120 oC and 4 MPa is **85.2%**.[ \[Art. #ARTNUM\]](#article-96263-2018117044)

1.2.1 Thermal compression
Dewatering of Sewage Sludge Using Thermal Compression
Mechanical compression is a traditional process for the dewatering of sewage sludge. However, the moisture content of the cake is still high, unfavorable for the sludge management. In this paper, the use of thermal compression to improve the sludge dewatering is investigated. The dewatering efficiency is affected by the applied temperature, pressure and the sludge mass. The bound water of the sludge is further reduced by thermal compression, improving the dewatering performance. The solid content of the cake obtained after 10 min mechanical compression and 60 min thermal compression at 120 oC and 4 MPa is 85.2%.
08/01/2012 00:00:00
Link to Article
1.2.2 Thermal compression
Dewatering Performance of Sewage Sludge during the Thermal Compression Process
Sewage sludge proves to be difficult to dewater due to its composition and biological nature, and it is unsuitable for disposal with high moisture content. In the present work, sewage sludge is dewatered by the thermal compression, which shows unique separation advantages of various materials, and the effects of applied temperature and pressure on the dewatering performance are investigated. The filtrate SCOD reveals that higher temperature benefits the disruption of sludge flocs, resulting in the release of organic content. According to the accumulative filtrate volume, higher temperature and pressure facilitate the dewatering process, obtaining sludge cake with lower moisture content.
01/01/2014 00:00:00
Link to Article

1.3 Hydraulic compression

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A hydraulic compressor is any type of air compressor that is powered by hydraulics on a vehicle or machine. Hydraulic compressors convert hydraulic power into mechanical power, and then mechanical power to pneumatic power. [\[link\]](https://en.wikipedia.org/wiki/Hydraulic_compressor) **Highlights:** * Based on the traditional processes, **sludge dewatered** by usual methods was further dewatered by **hydraulic compression** and the filtrate released was treated by anaerobic fermentation. The difficulties in sludge dewatering were associated with the existence of sludge flocs or colloidal materials. A suitable **CaO dosage** of 125 mg/g dry sludge (DS) could further decrease the moisture content of sludge from 82.4 to 50.9 %. [\[Art. #ARTNUM\]](#article-96029-2026853025) * **Thermally assisted mechanical dewatering (TAMD)** is a new process for **energy-efficient liquid/solids separation** which enhances conventional-device efficiency. The main idea of this process is to supply a flow of heat in mechanical dewatering processes to favour the reduction of the liquid content. This is not a new idea but the proposed combination, especially the chosen operating conditions ( T P T piston  = 80 °C), the **dry solid content of the press cake can reach 66%**, compared to 36% at ambient temperature. \[...\]  the experimental set-up consists of a **compression cell** inserted in a CARVER^®^ **hydraulic press** \[...\] The cell consists of a compressive piston, a hollowed cylindrical vessel and a filter medium. [\[Art. #ARTNUM\]](#article-96029-2017184243)

1.3.1 Hydraulic compression
Application of a thermally assisted mechanical dewatering process to biomass.
Abstract Thermally assisted mechanical dewatering (TAMD) is a new process for energy-efficient liquid/solids separation which enhances conventional-device efficiency. The main idea of this process is to supply a flow of heat in mechanical dewatering processes to favour the reduction of the liquid content. This is not a new idea but the proposed combination, especially the chosen operating conditions ( T P T piston  = 80 °C), the dry solid content of the press cake can reach 66%, compared to 36% at ambient temperature. A significant regression model, describing changes on final dry solids content with respect to independent variables, was established with determination coefficient, R 2 , greater than 88%. With an energy consumption of less than 150 kWh/m 3 , the use of the TAMD process before a thermal drying process leads to an energy saving of at least 30% on the overall separation chain.
01/01/2011 00:00:00
Link to Article
1.3.2 Hydraulic compression
Integrated treatment of municipal sewage sludge by deep dewatering and anaerobic fermentation for biohydrogen production.
The increasing sludge generated in wastewater treatment plants poses a threat to the environment. Based on the traditional processes, sludge dewatered by usual methods was further dewatered by hydraulic compression and the filtrate released was treated by anaerobic fermentation. The difficulties in sludge dewatering were associated with the existence of sludge flocs or colloidal materials. A suitable CaO dosage of 125 mg/g dry sludge (DS) could further decrease the moisture content of sludge from 82.4 to 50.9 %. The filtrate from the dewatering procedure was a potential substrate for biohydrogen production. Adding zero-valent iron (ZVI) into the anaerobic system improved the biohydrogen yield by 20 %, and the COD removal rate was lifted by 10 % as well. Meanwhile, the sludge morphology and microbial community were altered. The novel method could greatly reduce the sludge volume and successfully treated filtrate along with the conversion of organics into biohydrogen.
02/01/2015 00:00:00
Link to Article

1.4 Belt filter press

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The belt filter (sometimes called a belt press filter, or belt filter press) is an industrial machine, used for solid/liquid separation processes, particularly the dewatering of sludges in the chemical industry, mining and water treatment. [\[link\]](https://en.wikipedia.org/wiki/Belt_filter) **Highlights:** * The productive process of **dewatering chemical sludge with belt filter press** was applied and tested for the need of 300 kt/a ethylene plant in JiHua Company. The optimum belts velocity, belts intensive pressures, inlet sludge, inlet flocculent and outlet sludge quantities were determined.[ \[Art. #ARTNUM\]](#article-96045-2376420144) * **Gravity belt thickening** is commonly used for dewatering activated sludge. However, only a few results concerning this process, and the mathematical description of the drainage of residual sludges, have been published. Laboratory drainage experiments were carried out on several **activated sludges** to compare different published modelling approaches. [\[Art. #ARTNUM\]](#article-96045-1985843659) * A **belt filter press** was chosen following laboratory work as the most **cost efficient equipment for dewatering the sludge**. A **mobile** belt filter press was brought to the sludge lagoon site and was used during the dewatering operation.[ \[Art. #ARTNUM\]](#article-96045-2340823079) * By **enzymatic hydrolsis** it is possible to modify the hydrophilic, water-retaining organic compounds of the sludge in order to reduce its water content. **Enzymes improve mechanical dewatering** in common **belt-type filter presses** or decanters in combination with flocculation by means of special **flocculating aids**. [\[Art. #ARTNUM\]](#article-96045-2804630631) * Included are flexibility through use of the three methods, a soil-slurry cutoff wall around the plant site perimeter and another slurry cutoff wall around the sludge monofill, and **belt filter presses** that **dewater the sludge** using **polymer as a coagulant aid**. [\[Art. #ARTNUM\]](#article-96045-1498470584)

1.4.1 Belt filter press
Enhancing the dewaterability of anaerobically digested sludge using fibrous materials recovered from primary sludge: demonstration from a field study
Sludge dewatering is an important process for determining the operation cost of sludge disposal. Hence, improving the dewaterability of anaerobically digested sludge containing high water content is of paramount significance. For this challenge, we developed a novel process in which fibrous materials initially collected from a primary sedimentation tank, namely recovered fibers, were used as an auxiliary agent to improve the dewaterability of anaerobically digested sludge. The objective of this study was to investigate the feasibility of using the developed process to improve sludge dewaterability. Three fibrous materials individually recovered from the respective primary sedimentation tanks in different wastewater treatment plants (WWTPs) were used to investigate sludge dewaterability, organic C compositions, and calorific values. The recovered fibers showed comparable compositions irrespective of the WWTP. Six different WWTP sludge samples after anaerobic digestion were continuously supplied to three different dewatering devices, i.e., screw press, centrifuge, and belt press machines, with or without the supply of recovered fibers. Irrespective of the type of a dewatering device, the supply of recovered fibers mixed with the tested sludge samples at a feed ratio of 0.18–0.20 g-fibers/g-sludge (dry weight) reduced the amount of polymer flocculant by 13–50%, thereby displaying the superiority of the addition of recovered fibers. Furthermore, at fiber feed ratios of 0.20 g-fibers/g-sludge and 0.40 g-fibers/g-sludge when the rates of sludge supply and polymer flocculant were kept constant, the corresponding water contents in the dewatered sludge cakes decreased to about 74–76% and 69–72%, respectively. The consistent results regardless of the dewatering device or sludge sample showed the significance of the addition of recovered fibers for improvement in sludge dewaterability.
04/24/2019 00:00:00
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1.4.2 Belt filter press
Gravity drainage of activated sludge: from laboratory experiments to industrial process
Gravity belt thickening is commonly used for dewatering activated sludge. However, only a few results concerning this process, and the mathematical description of the drainage of residual sludges, have been published. Laboratory drainage experiments were carried out on several activated sludges to compare different published modelling approaches. Data showed a linear relationship between the infinite mass of the cake (M C ) and the total mass of the dry solids in the initial sludge sample (DS): M C = α 1 x DS + α 2 so, an empirical equation was modified to predict the evolution of the cake dry solids content-over time: DS C (t) = DS/(α 1 × DS + α 2 ) + (c 1 x exp(c 2 x DS) × t + 1 M 0 - (α 1 × DS + α 2 ) -1 Two sets of empirical coefficients were derived according to the range of the initial dry solids content of the sludge (C b 2%). These coefficients were not significantly influenced by the origin of the activated sludge and thus can be considered as constants. Simulation results using the chosen model accord will with experiments carried out on an industrial gravity belt thickener working under field conditions.
05/01/2004 00:00:00
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1.4.3 Belt filter press
Improved Sludge Dewatering by Enzymatic Treatment
Nowadays West Germany produces 50 million cubic metres of liquid sludge per year. This tendency is still on the increase, whereas traditional means of utilisation, such as in agriculture, show a sharp decline. For this reason, about 60 - 70 % of the sludge has to be deposited at waste tips with a limited capacity. Therefore it is highly desirable to reduce the sludge volume as much as possible. By enzymatic hydrolsis it is possible to modify the hydrophilic, water-retaining organic compounds of the sludge in order to reduce its water content. Enzymes improve mechanical dewatering in common belt-type filter presses or decanters in combination with flocculation by means of special flocculating aids.
07/01/1993 00:00:00
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1.4.4 Belt filter press
Lime Sludge Lagoon Dewatering Using a Mobile Belt Filter Press
A major company was faced with the removal of 2100 cubic yards of lime sludge stored in three lagoons. Because the sludge contained relatively high concentrations of tin and nickel, it was classified as a hazardous waste and required disposal in a hazardous waste landfill located over 400 miles from the manufacturing facility. Because of the high cost due to transportation of the solidified sludge, the contractor investigated several dewatering techniques. A belt filter press was chosen following laboratory work as the most cost efficient equipment for dewatering the sludge. A mobile belt filter press was brought to the sludge lagoon site and was used during the dewatering operation. As an end result, approximately 2100 cubic yards of the sludge was dewatered and transported to the hazardous waste landfill at a cost of under 200,000. 00. A detailed case history of the dewatering operation is presented. (Edited author abstract. )
01/01/1985 00:00:00
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1.4.5 Belt filter press
Productive application of dewatering chemical sludge with belt filter press
The productive process of dewatering chemical sludge with belt filter press was applied and tested for the need of 300 kt/a ethylene plant in JiHua Company.The optimum belts velocity ,belts intensive pressures,inlet sludge, inlet flocculent and outlet sludge quantities were determined .Technological and economic indexes to be guaranteed were finished with higher economic and environmental profit.A great number of running fees can be saved by applying DYQ2000-XB model belt filter press instead of WL(F)-600Ⅱ model centrifuge in the condition of same outlet sludge quantities.
01/01/2005 00:00:00
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1.4.6 Belt filter press
Sludge Disposal Dallas Style
Dallas, Tex. has discovered that sludge disposal can coexist with environmental concerns. Dallas Water Utilities treats some 200 million gpd, sending the effluent from one of the two treatment facilities to the other, the Southside Plant, where the sludge was disposed of on-site by liquid injjection into dedicated land disposal fields. In 1985 a Sludge Master Plan was adopted that recommended anaerobic digestion of all sludges, mechanical dewatering and sludge disposal by three methods: 1) on-site dedicated land disposal, 2) on-site sludge-only monofill, and 3) composting. Under this Plan, a new facility, the first phase of a $90 million project had been constructed. The design team retained by the city confirmed that these methods would be the most cost effective. Their design includes several innovations that have attracted observers to the plant. Included are flexibility through use of the three methods, a soil-slurry cutoff wall around the plant site perimeter and another slurry cutoff wall around the sludge monofill, and belt filter presses that dewater the sludge using polymer as a coagulant aid. Mixing the sludge with soil in a pug mill prior to disposal, pre-testing dewatering equipment prior to award, contracting operation of the monofill to private company are also included.
01/01/1990 00:00:00
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1.5 Rotary press

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A Rotary Press works at a low speed of rotation. It is a durable system with low maintenance expenses and energy consumption. This dewatering system uses screen plates for solid-liquid separation. [\[link\]](https://www-sciencedirect-com.vu-nl.idm.oclc.org/science/article/pii/S0041624X17303499?via%3Dihub) **Highlights:** * Originally developed by a Canadian governmental agency for **dewatering industrial sludges** such as paper pulp, the **rotary press technology** has been found to compare favourably with conventional dewatering technologies, in terms of cake dryness and suspended solids capture rates.[ \[Art. #ARTNUM\]](#article-96279-2513865741) * A method and apparatus for treating **liquid waste water sludge** after its generation and separation from the waste liquid involves propelling a plurality of separate streams of sludge via, for instance, a **rotor** (37) and then forcibly impacting sludge particles and microbial cells contained in the propelled streams of sludge against a contact surface such as a stator (59), for recirculation of sludge along toroidal paths (62) and (64), to thereby **fragment the particles** into smaller sized particles and break apart the organic cells. As a result of such a fragmentation process, **water** located in the pores of the sludge particles **is released**, thereby enhancing a subsequent dewatering process performed on the sludge.[ \[Art. #ARTNUM\]](#article-96279-1538660948)

1.5.1 Rotary press
Apparatus and Method for Treatment of Waste Water Sludge
A method and apparatus for treating liquid waste water sludge after its generation and separation from the waste liquid involves propelling a plurality of separate streams of sludge via, for instance, a rotor (37) and then forcibly impacting sludge particles and microbial cells contained in the propelled streams of sludge against a contact surface such as a stator (59), for recirculation of sludge along toroidal paths (62) and (64), to thereby fragment the particles into smaller sized particles and break apart the organic cells. As a result of such a fragmentation process, water located in the pores of the sludge particles is released, thereby enhancing a subsequent dewatering process performed on the sludge. The destruction of the cells permits a subsequent solids digestion process to work more efficiently, while also permitting a more complete conversion to dissolved sugars, proteins and carbon dioxide.
02/17/1993 00:00:00
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1.5.2 Rotary press
Effective, economic and easy dewatering of sludges
Originally developed by a Canadian governmental agency for dewatering industrial sludges such as paper pulp, the rotary press technology has been found to compare favourably with conventional dewatering technologies, in terms of cake dryness and suspended solids capture rates. Tony Clutten, Delkor Ltd, UK, which is now marketing the rotary press in the UK and Ireland, explains how the technology works and presents performance data.
01/01/2003 00:00:00
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1.5.3 Rotary press
Method for treatment of waste water sludge
A method for treating liquid waste water sludge after its generation and separation from the waste liquid involves forcibly impacting sludge particles and microbial cells against a contact surface to thereby fragment the particles into smaller-sized particles and break apart the organic cells. As a result of such a fragmentation process, water located in the pores of the sludge particles is released, thereby enhancing a subsequent dewatering process performed on the sludge. The destruction of the cells permits a subsequent solids digestion process to work more efficiently, while also permitting a more complete conversion to dissolved sugars, proteins and carbon dioxide.
11/24/1992 00:00:00
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1.6 Vacuum filtration

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Dewatering methods using a vacuum filter. **Highlights:** * The efficiency and the cost of dewatering lime and alum generated physical-chemical treatment sludge were developed utilizing a **continuous vacuum filter** and a solid bowl conveyor centrifuge. \[...\] **Vacuum filters are the least-cost approach** based on the results of the field studies. [\[Art. #ARTNUM\]](#article-96273-2275547947) * The **aeration-vacuum dewatering method** is a new kind of solid-liquid separate technique. The filter clogging problem in the routine vacuum dewatering procedure of sludge can be solved by the method. This method is used to **dewater the sewage sludge** in this paper.[ \[Art. #ARTNUM\]](#article-96273-2165618903) * **The sludge dewatering with aeration-vacuum (SDAV) method** is suit for treating the sludge with high water content and high clay content in the disposal site. The water in the sludge can be discharged out. The volume of the sludge can be reduced quickly, and the recycling of the land can be accelerated by this method. Most importantly, this technique is an efficient way to deal with clogging problems when pumping water from high water content, high clay content dredged sludge. [\[Art. #ARTNUM\]](#article-96273-2055512403)

1.6.1 Vacuum filtration
Dewatering Chemical-Primary Sludges
The efficiency and the cost of dewatering lime and alum generated physical-chemical treatment sludge were developed utilizing a continuous vacuum filter and a solid bowl conveyor centrifuge. Centrifugal dewatering included evaluation of both single-stage and two-stage classification dewatering. The evaluation of the data showed that lime recovery was economical with both a single and two-state centrifugal as well as vacuum filter above the plant size of 25,000,000 gal/day. Tables show the comparative cost of dewatering the lime and alum sludges for various sizes of treatment plants and with costs itemized for capital and operating considerations. Vacuum filters are the least-cost approach based on the results of the field studies. The paper also shows the process effects of varying operating parameters for these centrifuge and vacuum filter operations.
10/01/1976 00:00:00
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1.6.2 Vacuum filtration
Effect of vacuum degree and aeration rate on sludge dewatering behavior with the aeration-vacuum method
Due to large-scale dredging operations, a large amount of sludge is inevitably produced. Large areas of land are occupied when the dredged sludge is discarded in the disposal site as waste material. The sludge dewatering with aeration-vacuum (SDAV) method is suit for treating the sludge with high water content and high clay content in the disposal site. The water in the sludge can be discharged out. The volume of the sludge can be reduced quickly, and the recycling of the land can be accelerated by this method. Most importantly, this technique is an efficient way to deal with clogging problems when pumping water from high water content, high clay content dredged sludge. Vacuum degree range tests, the aeration rate range tests, and the influencing factors of sludge dewatering behavior tests were conducted with a self-developed SDAV model test device. Sludge samples were taken from the South-to-North Water Diversion East Line Project in Huai’an White-Horse Lake disposal site, Jiangsu Province, China. The optimal range of vacuum degree and aeration rate were obtained through the test results, and the mechanisms for how the two factors work and how they affect the sludge dewatering behavior were analyzed. The suitable vacuum degree range in SDAV is below 50 kPa, and the suitable aeration rate is about 1.0 m3/h. The low-vacuum degree contributes to reduce the adsorption effect of micro-channels on soil particles in filter material and to maintain the arch structures. Aeration has the effects of expansion, disturbance, changing Reynolds number, and dynamic sieve separating. The pump quantity of water per meter of filter tube (Δm) has different change rules as the vacuum degree changes under different aeration rates. The reason is that the formed arch structures’ conformation and permeability differ greatly under different combined-conditions of vacuum degree and aeration rate. The optimal combined-condition for dewatering the sludge is 35 kPa with 1.0 m3/h.
09/01/2010 00:00:00
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1.6.3 Vacuum filtration
Test Study on Dewatering Effect of Sewage Sludge by Vacuum Method
The aeration-vacuum dewatering method is a new kind of solid-liquid separate technique. The filter clogging problem in the routine vacuum dewatering procedure of sludge can be solved by the method. This method is used to dewater the sewage sludge in this paper. Through the dewatering model test of the sewage sludge with this method, the change law of the solid content and the volume of the sewage sludge are studied. The dewatering effect of sewage sludge is got further more. The test results indicate that there is a great promotion for improving the solid content and reducing the volume by using the aeration-vacuum method.
01/01/2012 00:00:00
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1.7 Vibration screen

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A Vibrating Screen is a common system used for dewatering in mining. It offers high capacity or throughput as well as low energy consumption. The vibration frequency in these machines is normally between 30 and 60 Hz. [\[link\]](https://www-sciencedirect-com.vu-nl.idm.oclc.org/science/article/pii/S0041624X17303499?via%3Dihub) **Highlights:** * The aim of this study was to determine the effectiveness of natural **flocculants** to reduce solids and nutrient loads in **dairy cow wastewater using solid–liquid separation**; **chitosan** was used as a model. \[...\] Mixing with chitosan before **screening** substantially **increased separation.** At optimum chitosan rate (0.5 g/L for the highest strength effluent), separation efficiencies were >95% for TSS, >73% for TKN, and >54% for TP.[ \[Art. #ARTNUM\]](#article-96044-1972255669) * The performance of a **vibratory shear-enhanced membrane process** for **dewatering of freshwater microalgae**, Chlorella vulgaris, has been studied. Chlorella vulgaris is a potential **renewable feedstock for biofuel and bioproduct** production. \[...\] This process could provide a greener alternative to conventional mechanical and thermal separation systems, as high values of permeate flux and separation efficiency can be maintained with an **energy consumption of 1.6 kWh/m3 of water removed.** [\[Art. #ARTNUM\]](#article-96044-1980289160)

1.7.1 Vibration screen
Enhanced solid-liquid separation of dairy manure with natural flocculants.
Abstract The aim of this study was to determine the effectiveness of natural flocculants to reduce solids and nutrient loads in dairy cow wastewater using solid–liquid separation; chitosan was used as a model. Its use efficiency and optimum application rate were determined using flushed dairy cow manure of varied strengths – 0.4%, 0.8%, 1.6%, and 3.2% total solids (TS) content. Treatments consisted of nine rates of chitosan. The flocculated manure was dewatered using 1-mm and 0.25-mm screens. Separation by screening alone was not effective; average efficiencies were about 60% for total suspended solids (TSS), 22% for total Kjeldahl nitrogen (TKN), and 26% for total phosphorus (TP). Mixing with chitosan before screening substantially increased separation. At optimum chitosan rate (0.5 g/L for the highest strength effluent), separation efficiencies were >95% for TSS, >73% for TKN, and >54% for TP. The results of this study indicate that natural flocculants such as chitosan are useful for the solid–liquid separation treatment of livestock wastewater.
11/01/2009 00:00:00
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1.7.2 Vibration screen
Shear-enhanced microfiltration of microalgae in a vibrating membrane module.
The performance of a vibratory shear-enhanced membrane process for dewatering of freshwater microalgae, Chlorella vulgaris, has been studied. Chlorella vulgaris is a potential renewable feedstock for biofuel and bioproduct production. The efficient dewatering of the algal biomass is crucial for scale-up and sustainable design. This dynamic filtration system achieves high shear rates desirable for microfiltration by high-frequency torsional oscillations of the membrane unit. A 0.05 µm (nominal pore size) polyethersulfone microfiltration membrane was evaluated for the separation of suspended algae (0.5–100 g/L). The effect of process parameters such as trans-membrane pressure, surface shear rate, and solute concentration on permeate flux was evaluated and quantified. Algal biomass mixtures were dewatered with high algae rejections for all studies. The effect of trans-membrane pressure on permeate flux showed a classic pattern of a pressure-controlled region at lower pressures transforming to a mass transfer gel layer-controlled region at higher pressures, with quicker transitions at higher algae feed concentrations. The shear rate at the membrane surface was varied by changing the vibrational frequency of the unit. Permeate flux values observed in dynamic filtration mode, compared to those in cross-flow filtration (CFF) mode, were greater by a factor of 4.2–4.9. This process could provide a greener alternative to conventional mechanical and thermal separation systems, as high values of permeate flux and separation efficiency can be maintained with an energy consumption of 1.6 kWh/m3 of water removed.
10/01/2015 00:00:00
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1.8 Geotextile tube

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Geotextiles are permeable fabrics which, when used in association with soil, have the ability to separate, filter, reinforce, protect, or drain. [\[link\]](https://en.wikipedia.org/wiki/Geotextile) **Note:** also includes other filter bags **Highlights:** * **Geotextile tube** is an innovative product developed by sewing permeable high strength geotextiles to form large tubes. The main application of geotextile tube is **dewatering of dredged materials sediments and industrial waste slurry**. The present study describes the performance of **dairy sludge** dewatering using hanging bag test. The effect of the addition of **coagulant** has been studied. \[...\] It was found that geotextile tube was efficient in dewatering the sludge and its **efficiency increases** with the **addition of a coagulant.**[ \[Art. #ARTNUM\]](#article-96255-2744274664) * The **innovative pit design** which also function as **sludge dewatering** system is low cost, easy to implement and highly efficient. The system uses a mobile metal cage lined with a **filter bag** to collect the sludge. Based on this design, emptying the pit and transporting the dewater sludge is far much cheaper and easier than current practice (using vacuum trucks). The dewatering technique uses time instead of pressure to dewater the sludge.[ \[Art. #ARTNUM\]](#article-96255-2511094392)

1.8.1 Geotextile tube
Geotextile Tube Assessment Using Hanging Bag Test Results of Dairy Sludge
Geotextile tube is an innovative product developed by sewing permeable high strength geotextiles to form large tubes. The main application of geotextile tube is dewatering of dredged materials sediments and industrial waste slurry. The present study describes the performance of dairy sludge dewatering using hanging bag test. The effect of the addition of coagulant has been studied. Alum was used as a coagulant. Dewatering was carried out for dairy sludge without the addition of alum and dairy sludge mixed with alum. The environmental analysis was carried out of the sludge before and after hanging bag test to study the quality of filtrate. Also, analysis of filter cake was done to check its suitability for reuse thus proving zero waste condition. It was found that geotextile tube was efficient in dewatering the sludge and its efficiency increases with the addition of a coagulant. Dairy sludge dewatering without the addition of alum showed the maximum flow rate of 4.95 cm3/sec and dewatering time of 2280 min as compared to dairy sludge dewatering with the addition of alum which showed the maximum flow rate of 7.66 cm3/sec and dewatering time of 2160 min.
09/01/2017 00:00:00
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1.8.2 Geotextile tube
Innovative pit design and sludge dewatering for rural areas
Abstract This article addresses an innovative pit design and sludge dewatering in rural areas in developing countries. The innovative pit design which also function as sludge dewatering system is low cost, easy to implement and highly efficient. The system uses a mobile metal cage lined with a filter bag to collect the sludge. Based on this design, emptying the pit and transporting the dewater sludge is far much cheaper and easier than current practice (using vacuum trucks). The dewatering technique uses time instead of pressure to dewater the sludge. The results showed that a pit with 4 m 3 capacity can save the owner the cost of emptying the pit and 83% the cost of transporting the sludge via current method. It also saves the water treatment plant around $50 cost of dewatering the sludge from a single pit using dewatering machines.
12/01/2016 00:00:00
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1.9 Tangential flow filtration

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Crossflow filtration (also known as tangential flow filtration) is a type of filtration (a particular unit operation). Cross-flow filtration gets its name because the majority of the feed flow travels tangentially across the surface of the filter, rather than into the filter. [\[link\]](https://en.wikipedia.org/wiki/Cross-flow_filtration) **Highlights:** * This study explores the influence of microalgal growth phases and intercellular interactions during cultivation on **dewatering efficiency of microalgae cultures**. Experimental results show that microalgal cultures harvested during a low growth rate phase (LGRP) of 0.03 d-1 allowed a higher rate of settling than those harvested during a high growth rate phase (HGRP) of 0.11 d-1, even though the latter displayed a higher average differential biomass concentration of 0.2 g L-1 d-1. \[...\] **Tangential flow filtration** of 20 L HGRP culture **concentrated 23 times** by consuming 0.51 kWh/m3 of supernatant removed whilst 0.38 kWh/m3 was consumed to concentrate 20 L of LGRP by 48 times. [\[Art. #ARTNUM\]](#article-96315-2093657772) * This article reports an effective framework to assess the performance of different **dewatering technologies** as the basis to establish an effective **two-stage dewatering system**.\[...\] **Bioflocculation coupled with tangential flow filtration (TFF)** emerged a promising technique with total energy input of 0.041 kWh, 0.05 kg CO2 emissions and a cost of $ 0.0043 for producing 1 kg of microalgae biomass.[ ](#article-96314-2260003424)[\[Art. #ARTNUM\]](#article-96315-2260003424)

1.9.1 Tangential flow filtration
Development of a Two-Stage Microalgae Dewatering Process – A Life Cycle Assessment Approach
Even though microalgal biomass is leading the third generation biofuel research, significant effort is required to establish an economically-viable commercial-scale microalgal biofuel production system. Whilst a significant amount of work has been reported on large-scale cultivation of microalgae using photo-bioreactors and pond systems, research focus on establishing high performance downstream dewatering operations for large-scale processing under optimal economy is limited. The enormous amount of energy and associated cost required for dewatering large-volume microalgal cultures has been the primary hindrance to the development of the needed biomass quantity for industrial-scale microalgal biofuels production. The extremely dilute nature of large-volume microalgal suspension and the small size of microalgae cells in suspension create a significant processing cost during dewatering and this has raised major concerns towards the economic success of commercial-scale microalgal biofuel production as an alternative to conventional petroleum fuels. This article reports an effective framework to assess the performance of different dewatering technologies as the basis to establish an effective two-stage dewatering system. Bioflocculation coupled with tangential flow filtration (TFF) emerged a promising technique with total energy input of 0.041 kWh, 0.05 kg CO2 emissions and a cost of $ 0.0043 for producing 1 kg of microalgae biomass. A streamlined process for operational analysis of two-stage microalgae dewatering technique, encompassing energy input, carbon dioxide emission and process cost, are presented.
02/11/2016 00:00:00
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1.9.2 Tangential flow filtration
Microalgal growth characteristics and subsequent influence on dewatering efficiency
Dewatering of microalgal culture is a major bottleneck towards the industrial-scale processing of microalgae for bio-diesel production. The dilute nature of harvested microalgal cultures poses a huge operation cost to dewater; thereby rendering microalgae-based fuels less economically attractive. This study explores the influence of microalgal growth phases and intercellular interactions during cultivation on dewatering efficiency of microalgae cultures. Experimental results show that microalgal cultures harvested during a low growth rate phase (LGRP) of 0.03 d-1 allowed a higher rate of settling than those harvested during a high growth rate phase (HGRP) of 0.11 d-1, even though the latter displayed a higher average differential biomass concentration of 0.2 g L-1 d-1. Zeta potential profile during the cultivation process showed a maximum electronegative value of -43.2 ± 0.7 mV during the HGRP which declined to stabilization at -34.5 ± 0.4 mV in the LGRP. The lower settling rate observed for HGRP microalgae is hence attributed to the high stability of the microalgal cells which electrostatically repel each other during this growth phase. Tangential flow filtration of 20 L HGRP culture concentrated 23 times by consuming 0.51 kWh/m3 of supernatant removed whilst 0.38 kWh/m3 was consumed to concentrate 20 L of LGRP by 48 times.
08/01/2009 00:00:00
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1.10 Screw press

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A dewatering screw press is a screw press that separates liquids from solids. It is a simple, slow moving device that accomplishes dewatering by continuous gravitational drainage. Screw presses are often used for materials that are difficult to press, for example those that tend to pack together. The screw press squeezes the material against a screen or filter and the liquid is collected through the screen for collection and use. [\[link\]](https://en.wikipedia.org/wiki/Dewatering_screw_press) **Highlights:** * To provide a **screw type dewatering apparatus** which shakes swing rings well to improve dewatering efficiency, and in which a swing ring driving means is hardly worn out so that life of the swing ring driving means is substantially extended.[ \[Art. #ARTNUM\] ](#article-96317-2821689307) * The objective of the work presented is to develop a mechanically based pretreatment process for biomass using a screw press. The **screw press** used for this purpose is an oil press which is known to provide continuous high shear and pressure forces. The results obtained in this study show the feasibility and potential for **degradation of the lignocellulosic structure** as well as **dewatering of biomass in the screw press.**[ \[Art. #ARTNUM\]](#article-96317-2303649050) * The **sludge dewatering** performance of **screw press dehydrator** was investigated.The results show that for the digested sludge with moisture content of 97.9%, under the condition of flocculant dosing rate of 0.51% and screw speed of 0.25 r/min, the minimum **cake moisture content after dewatering is 70.3%, the solid recovery is 98.89%** and the sludge treatment capacity is 24.84 kg/h. For the excess sludge with moisture content of 99.7%, under the condition of **flocculant** dosage rate of 0.94% and screw speed of 0.75 r/min, the cake moisture content after dewatering is 82.5%, the solid recovery is 92.46%, and the sludge treatment capacity is 8.64 kg/h.[ \[Art. #ARTNUM\]](#article-96317-2378189068)

1.10.1 Screw press
Enhancing the dewaterability of anaerobically digested sludge using fibrous materials recovered from primary sludge: demonstration from a field study
Sludge dewatering is an important process for determining the operation cost of sludge disposal. Hence, improving the dewaterability of anaerobically digested sludge containing high water content is of paramount significance. For this challenge, we developed a novel process in which fibrous materials initially collected from a primary sedimentation tank, namely recovered fibers, were used as an auxiliary agent to improve the dewaterability of anaerobically digested sludge. The objective of this study was to investigate the feasibility of using the developed process to improve sludge dewaterability. Three fibrous materials individually recovered from the respective primary sedimentation tanks in different wastewater treatment plants (WWTPs) were used to investigate sludge dewaterability, organic C compositions, and calorific values. The recovered fibers showed comparable compositions irrespective of the WWTP. Six different WWTP sludge samples after anaerobic digestion were continuously supplied to three different dewatering devices, i.e., screw press, centrifuge, and belt press machines, with or without the supply of recovered fibers. Irrespective of the type of a dewatering device, the supply of recovered fibers mixed with the tested sludge samples at a feed ratio of 0.18–0.20 g-fibers/g-sludge (dry weight) reduced the amount of polymer flocculant by 13–50%, thereby displaying the superiority of the addition of recovered fibers. Furthermore, at fiber feed ratios of 0.20 g-fibers/g-sludge and 0.40 g-fibers/g-sludge when the rates of sludge supply and polymer flocculant were kept constant, the corresponding water contents in the dewatered sludge cakes decreased to about 74–76% and 69–72%, respectively. The consistent results regardless of the dewatering device or sludge sample showed the significance of the addition of recovered fibers for improvement in sludge dewaterability.
04/24/2019 00:00:00
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1.10.2 Screw press
Experimental Research on Sludge Dewatering by Screw Press Dehydrator
The sludge dewatering performance of screw press dehydrator was investigated.The results show that for the digested sludge with moisture content of 97.9%,under the condition of flocculant dosing rate of 0.51% and screw speed of 0.25 r/min,the minimum cake moisture content after dewatering is 70.3%,the solid recovery is 98.89% and the sludge treatment capacity is 24.84 kg/h.For the excess sludge with moisture content of 99.7%,under the condition of flocculant dosage rate of 0.94% and screw speed of 0.75 r/min,the cake moisture content after dewatering is 82.5%,the solid recovery is 92.46%,and the sludge treatment capacity is 8.64 kg/h.Compared with belt dehydrator,the sludge treatment effect is greatly improved.
01/01/2009 00:00:00
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1.10.3 Screw press
Mechanical Pretreatment of Lignocellulosic Biomass Using a Screw Press as an Essential Step in the Biofuel Production
Since mechanical pretreatment makes lignocellulosic biomass accessible to any further solution and (bio-)chemical modification processes, it is a step which is essential for the entire downstream processing. The objective of the work presented is to develop a mechanically based pretreatment process for biomass using a screw press. The screw press used for this purpose is an oil press which is known to provide continuous high shear and pressure forces. The results obtained in this study show the feasibility and potential for degradation of the lignocellulosic structure as well as dewatering of biomass in the screw press. Adsorption and extraction studies indicate that the products from the screw press have a larger specific surface area and more disruption of cell structure than those treated only with a cutting mill. Furthermore, it is found that the process with a screw press requires considerably less energy in comparison to the conventional thermal-mechanical process.
09/20/2012 00:00:00
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1.10.4 Screw press
SCREW TYPE DEWATERING APPARATUS FOR IMPROVING DEWATERING EFFICIENCY BY SEPARATION MEANS INCLUDING FIXING RINGS AND CIRCULAR SWING RINGS, DRIVING PLATES INSTALLED ON SEPARATION MEANS AND SUPPORTING BARS FIXED TO DRIVING PLATES
PURPOSE: To provide a screw type dewatering apparatus which shakes swing rings well to improve dewatering efficiency, and in which a swing ring driving means is hardly worn out so that life of the swing ring driving means is substantially extended. CONSTITUTION: The screw type dewatering apparatus comprises a separation tank(10) on both sides of which a sludge supply part and a solid discharge part are formed; a separation means(20) comprising a plurality of fixing rings(21) fixed perpendicularly to an inner part of the separation tank with being distanced from each other in a certain gap, and a plurality of swing rings(22) disposed between the fixing rings with being spaced apart from the fixing rings in a small gap; a separation plate for dividing the separation means into a concentration zone at the sludge supply part side of a space part(S) and a dewatering zone at the solid discharge part side; a screw(30) which is installed in the space part formed in the separation means, and in which an inclined part(32') is formed on an end of the solid discharge part side in such a way that a blade(32) is more inclined to the sludge supply part side as it goes from the center to the outer circumferential surface of the screw; and a swing ring driving means(40) driven with being interlocked with the screw, the swing ring driving means comprising cams(41,41') fixed to both ends of screw shaft, driving plates(44,44') for supporting the center of the cams such that the driving plates are shaken along the contour of the cams at the outside of the cams, and at least three or more supporting bars(45) which fix the swing rings, and both ends of which are fixed to the driving plates so that the swing rings are shaken along the contour of the cams, wherein the supporting bars are closely adhered to the outer circumferential surface of the swing rings such that the supporting rings support the swing rings by controlling the swing rings, and reinforcement rings are installed on an outer surface part of the supporting bars closely adhered to the swing rings to prevent deformation of the supporting bars.
12/29/2004 00:00:00
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1.11 Magnetic filtration

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Magnetic separation is the process of separating components of mixtures by using magnets to attract magnetic materials. [\[link\]](https://en.wikipedia.org/wiki/Magnetic_separation) **Highlights:** * Magnetic separation is a powerful tool to capture algae by adsorption to submicron-sized magnetic particles. \[...\] This study highlights the potential of **silica-coated magnetic particles** for the removal of fresh water and marine **algae** by **high gradient magnetic filtration** and provides critical discussion on future improvements. [\[Art. #ARTNUM\]](#article-96331-2047327152)

1.11.1 Magnetic filtration
Harvesting fresh water and marine algae by magnetic separation: screening of separation parameters and high gradient magnetic filtration.
Abstract In this study, the focus is on magnetic separation of fresh water algae Chlamydomonas reinhardtii and Chlorella vulgaris as well as marine algae Phaeodactylum tricornutum and Nannochloropsis salina by means of silica-coated magnetic particles. Due to their small size and low biomass concentrations, harvesting algae by conventional methods is often inefficient and cost-consuming. Magnetic separation is a powerful tool to capture algae by adsorption to submicron-sized magnetic particles. Hereby, separation efficiency depends on parameters such as particle concentration, pH and medium composition. Separation efficiencies of >95% were obtained for all algae while maximum particle loads of 30 and 77 g/g were measured for C. reinhardtii and P. tricornutum at pH 8 and 12, respectively. This study highlights the potential of silica-coated magnetic particles for the removal of fresh water and marine algae by high gradient magnetic filtration and provides critical discussion on future improvements.
08/01/2012 00:00:00
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1.12 Osmotic separation

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Osmosis is the spontaneous net movement of solvent molecules through a selectively permeable membrane into a region of higher solute concentration, in the direction that tends to equalize the solute concentrations on the two sides. [\[link\]](https://en.wikipedia.org/wiki/Osmosis) **Highlights:** * Macroscopic experimental results show that: the vacuum filtration and centrifugation can only dewater the sludge from 94.5 to 78.3% and to 78.8%, respectively, whereas, using the **osmotic technique,** **water content of the sludge can be decreased to 44.2% in 12 h and to 35.9% in about two days**. \[...\] the future application of the osmotic technique in practice is discussed from the viewpoints of deep dewatering and **energy consumption.**[ \[Art. #ARTNUM\]](#article-96042-2884753744) * The potential application of **forward osmosis (FO)** in **microalgae dewatering** requires an improved understanding of the factors that control membrane fouling which can reduce dewatering performance in terms of water flux through membrane and algae recovery. The aim of this study was to elucidate the influence of algae cell wall carbohydrate composition on the FO dewatering performance using three types of draw solutions (sea salts, MgCl2 and CaCl2). \[...\] Both S. obliquus and C. reinhardtii did not cause obvious membrane fouling but dramatic algae biomass loss at the end of **FO filtration** with MgCl2 draw solution due to their interaction with back diffused Mg2 + ions which led to the deposition of algae flocs onto membrane surface and/or feed spacer. [\[Art. #ARTNUM\]](#article-96042-2574590304)

1.12.1 Osmotic separation
Dewatering sludge by osmotic technique – A comparative experimental study
AbstractThe present paper aims to introduce a novel and environment-friendly sludge dewatering method based on the osmotic technique, and to examine the efficiency of this method from macro- and micro-points of view. Intact sample, taken from the primary settler of a local wastewater treatment plant in Guangzhou (China), was firstly dewatered by mechanical methods (i.e. vacuum filtration and centrifugation), then by the osmotic technique. Macroscopic experimental results show that: the vacuum filtration and centrifugation can only dewater the sludge from 94.5 to 78.3% and to 78.8%, respectively, whereas, using the osmotic technique, water content of the sludge can be decreased to 44.2% in 12 h and to 35.9% in about two days. The micro-structure, obtained by scanning electron microscope (SEM), shows that: the sludge samples after vacuum filtration and centrifugation have a porous structure and water can be drained either through the cracks that have been developed under the vacuum pressure or by the micro-...
07/17/2018 00:00:00
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1.12.2 Osmotic separation
Microalgal biomass dewatering using forward osmosis membrane: Influence of microalgae species and carbohydrates composition
The potential application of forward osmosis (FO) in microalgae dewatering requires an improved understanding of the factors that control membrane fouling which can reduce dewatering performance in terms of water flux through membrane and algae recovery. The aim of this study was to elucidate the influence of algae cell wall carbohydrate composition on the FO dewatering performance using three types of draw solutions (sea salts, MgCl2 and CaCl2). Experimental results suggest that the interaction between microalgae and back diffused draw solutes plays a key role. Scenedesmus obliquus with fructose and abundant glucose and mannose in its cell wall showed strong response to the back diffusion of calcium ions which encouraged S. obliquus to produce more extracellular carbohydrates and formed a stable gel network between algal biomass and extracellular carbohydrates, leading to algae aggregation and severe loss in both water flux and algae biomass during FO dewatering with Ca2 +-containing draw solution. Chlamydomonas reinhardtii without fructose but great galactose showed a similar response to the calcium back diffusion but to a lower extent. Both S. obliquus and C. reinhardtii did not cause obvious membrane fouling but dramatic algae biomass loss at the end of FO filtration with MgCl2 draw solution due to their interaction with back diffused Mg2 + ions which led to the deposition of algae flocs onto membrane surface and/or feed spacer. Chlorella vulgaris without fructose was the most suitable microalgae species to be dewatered by FO with algae recovery over 81% and negligible flux decline regardless of which draw solution was applied. The findings improve mechanical understanding of FO membrane fouling by microalgae; have significant implications for the algae species selection; and are critical for the development and optimization of FO dewatering processes.
04/01/2017 00:00:00
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1.13 Other filtration technologies

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**Highligths:** * A **drainage/filtration apparatus** was developed for automatically determining sedimentation velocity and dewatering rate. \[...\] **Sludge must be dewatered** under low pressure, because higher pressure only compresses the cake and does not improve the dewatering rate.[ \[Art. #ARTNUM\]](#article-96001-2082542572) * This study operated a **two-stage filtration system** by batch modes to develop passive **solid–liquid separation of anaerobically digested dairy manure.** In the 1st-stage, **pebble filters** attained solid–liquid separation through surface filtration and evaporation. Filtration was completed after 7–33 d into each cycle of batch operation. **Evaporation** became the predominant mechanism for manure dewatering 2–3 weeks after each batch loading. Filtration was faster at higher temperatures, higher initial solids concentrations, and shorter times-to-filter. [\[Art. #ARTNUM\]](#article-96001-1984227424) * This study was to improve the dewatering rate as discharging the water from porosity of cake easily, supplying the **low heat** to the cake layer. **Thermal dewatering** equipment of piston type to keep up constant temperature on the cake was set up and relative experiment was conducted for **sludge of 200 g with fine pigment** particle. As test results. **filtration** of 176.8 g, cake weight of 19.4 g, cake thickness of 4.2 mm was measured, and it was analyzed that the water content of cake was 47 wt%. \[...\] This results showed that filtration increased, cake weight and thickness decreased and **dewatering velocity increased** against mechanical dewatering method. And **water content of cake decreased about 30%**, so the result which dewatering rate improved was drew generally. [\[Art. #ARTNUM\]](#article-96001-277809322)

1.13.1 Other filtration technologies
A study for High Efficiency Dewatering of Sludge Contained Fine Particles
There was some difficulty dewatering properties due to small porosity diameter of cake, when pigment sludge contained fine particle was formed by cake under the dewatering. It was difficult to dewater the sludge with fine particles with the conventional mechanical dewatering method. This study was to improve the dewatering rate as discharging the water from porosity of cake easily, supplying the low heat to the cake layer. Thermal dewatering equipment of piston type to keep up constant temperature on the cake was set up and relative experiment was conducted for sludge of 200 g with fine pigment particle. As test results. filtration of 176.8 g, cake weight of 19.4 g, cake thickness of 4.2 mm was measured, and it was analyzed that the water content of cake was 47 wt% and dewatering velocity, which moaned the residual d교 sloid amount per dewatering area, was . This results showed that filtration increased, cake weight and thickness decreased and dewatering velocity increased against mechanical dewatering method. And water content of cake decreased about 30%, so the result which dewatering rate improved was drew generally. The reason is that the inner vapor pressure working at the cake porosity increased as applying the low heat to the cake layer, which lead to discharge the water from porosity easily. Therefore, this study was estimated by the useful technology for sludge reduction.
01/01/2006 00:00:00
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1.13.2 Other filtration technologies
Compression and swelling of activated sludge cakes during dewatering
Abstract A drainage/filtration apparatus was developed for automatically determining sedimentation velocity and dewatering rate. Pressure-step testing was used to study filter cake compressibility, resistance, and swelling. Activated sludge was analysed, and the data indicate that the sludge is highly compressible even at low pressures (10 kPa). Furthermore, compressed sludge cakes swell if the pressure is released. Hence, the average specific cake resistance decreases if the pressure is released, though the resistance is higher after the compression cycle than before. Sludge must be dewatered under low pressure, because higher pressure only compresses the cake and does not improve the dewatering rate.
10/01/2012 00:00:00
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1.13.3 Other filtration technologies
Passive solid–liquid separation of anaerobically digested dairy manure using two-stage filtration
Solid–liquid separation makes further treatment and disposal of dairy manure easier. High concentrations of solids and long times-to-filter of anaerobically digested dairy manure present a challenge to cost-effective solid–liquid separation. This study operated a two-stage filtration system by batch modes to develop passive solid–liquid separation of anaerobically digested dairy manure. In the 1st-stage, pebble filters attained solid–liquid separation through surface filtration and evaporation. Filtration was completed after 7–33 d into each cycle of batch operation. Evaporation became the predominant mechanism for manure dewatering 2–3 weeks after each batch loading. Filtration was faster at higher temperatures, higher initial solids concentrations, and shorter times-to-filter. Two weeks after batch loadings, the pebble filters had removed 81.4–97.7% of total solids and 87.1–98.8% of total volatile solids from the filtrate and the manure retained on the pebble beds was thickened to 6.3–24.6% solids. Dewatering on the pebble beds was faster at a lower loading rate and more efficient at a higher loading rate (0.20 versus 0.16 and 0.12 m 3  m −2 ). In the 2nd-stage, the sand filters removed suspended solids via depth filtration.
04/01/2012 00:00:00
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2. Force and/or temperature based approaches

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Dewatering methods based on force and/or temperature without filtration. 


2.1 Centrifugation

0

Centrifugation is the technique which involves the application of centrifugal force to separate particles from a solution according to their size, shape, density, viscosity of the medium and rotor speed. [\[link\]](https://en.wikipedia.org/wiki/Centrifugation) **Note:** thermal treatments combined with centrifugation are included here. **Highlights:** * The study experimentally investigated the **centrifugal separation of moisture from activated sludge** subject to **cationic polyelectrolyte flocculation**. An **arm-suspended centrifuge** was employed which allowed in-situ detection on all positions of interfaces of centrifuged sludge as functions of time. Experimental results revealed that, sludge flocculation would yield a significant sedimentation effect at the first phase of centrifugation. [\[Art. #ARTNUM\]](#article-96004-1977816390) * Two automatic hydraulic backdrives and a direct current automatic torque controlled backdrive were tested on **centrifuges** used for **dewatering digested sludge** conditioned with a **polymer** and a combination of polymer and **ferric chloride**. The centrifuge unit of an advanced design coupled with the direct current automatic torque controlled backdrive produced a cake having a solids content of 30% and a **solids capture of 97%**. The regular production unit produced a cake having a solids content of 15% and a solids capture of 85%.[ ](#article-96039-2804237639)[\[Art. #ARTNUM\]](#article-96004-2804237639) * According to a **high-efficiency centrifugal dehydrator** for **improving dewaterability** of the present invention, a single ring-shaped blocking plate is disposed between a sludge discharge port of a screw conveyor in a centrifugal dehydrator drum and a cake discharge port of the drum so that a dehydration area in the drum can be narrowed, the pressure of the screw conveyor is maximized, and **dehydration efficiency can be increased.** [\[Art. #ARTNUM\]](#article-96004-2821153370) * A new sewage **sludge semi-drying (dewatering) process** is proposed and verified. It **combines thermal hydrolysis and subsequent mechanical dewatering**, with **less energy consumption** than traditional thermal drying. Sludge treated using this new process satisfies further disposal requirements (e.g., landfill or autothermal incineration). \[...\] Thermally hydrolyzed sludge was subsequently dewatered by **centrifugal sedimentation or by pressure filtration**. \[...\] The **moisture content** then dropped to 1.44 kg/kg dry solids (DS; 59 wt%) after **dewatering under relative centrifugal force** of 9,000 × g from 5.67 kg/kg DS (85 wt%). [\[Art. #ARTNUM\]](#article-96004-2028845792) * **Hydrothermal treatment** could **disrupt sludge cell** and release bound water finally **improve sludge dewaterability.** In this paper, bench scale experiments of sludge hydrothermal treatment were carried out. Results show that under a temperature from 140∞C to 180∞C and reaction time from 15min to 90min, **water content** of treated sludge could **reduce from 80% to about 50%.** \[...\] The sludge was heated by high temperature steam generated form a boiler under 180∞C. The treated sludge was **dewatered by a centrifuge**. [\[Art. #ARTNUM\]](#article-96004-2625584478)

2.1.1 Centrifugation
Characterization and dewaterability of raw and stabilized sludge using different treatment methods.
A comparison of the characteristics and stabilization potential of the four most used sludge treatment systems in Mexico was made. A pilot plant constituted by separate systems for anaerobic and aerobic digestion, lime stabilization, conditioning and dewatering, was built and operated during four months in one of the biological wastewater treatment plants in Acapulco, Mexico. Composting of sludge was also made. An aerobic static pile was built using bulking materials available in the region. A turbine centrifuge was used for dewatering the stabilized sludge and results showed good performance of the device. The main problem for the beneficial use of treated sludge was its pathogenicity. The composting process allowed us to obtain a product with approximately 20 fecal coliform density (MPN/g); with lime stabilization, the sludge produced had a fecal coliform density of 2 MPN/g. From these results, it is concluded that both the composting process and the alkaline stabilization with lime produce a well stabilized sludge, bacteriologically safe that accomplishes the requirements for its use on soil without restrictions. Related to parasitological removal, the best helminth egg removals were obtained also using these two processes. Ascaris sp. densities in raw sludge (309-430 eggs/g) were reduced to a final density of 3-14 eggs/g in the aerobic composting process and to 4-18 eggs/g in the lime stabilized sludge. Removal is not high enough to reach the recommended level for unrestricted use of stabilized sludge.
11/01/2002 00:00:00
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2.1.2 Centrifugation
Dewatering Chemical-Primary Sludges
The efficiency and the cost of dewatering lime and alum generated physical-chemical treatment sludge were developed utilizing a continuous vacuum filter and a solid bowl conveyor centrifuge. Centrifugal dewatering included evaluation of both single-stage and two-stage classification dewatering. The evaluation of the data showed that lime recovery was economical with both a single and two-state centrifugal as well as vacuum filter above the plant size of 25,000,000 gal/day. Tables show the comparative cost of dewatering the lime and alum sludges for various sizes of treatment plants and with costs itemized for capital and operating considerations. Vacuum filters are the least-cost approach based on the results of the field studies. The paper also shows the process effects of varying operating parameters for these centrifuge and vacuum filter operations.
10/01/1976 00:00:00
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2.1.3 Centrifugation
Effect of temperature on biogas yield increase and formation of refractory COD during thermal hydrolysis of waste activated sludge
Abstract Thermal hydrolysis (TH) increases the anaerobic biodegradability of waste activated sludge (WAS), but also refractory organic and nutrient return load to a wastewater treatment plant (WWTP). This could lead to an increase in effluent chemical oxygen demand (COD) of the WWTP. The aim of this study was to investigate the trade-off between increase in biogas production through TH and anaerobic digestion and increase in refractory COD in dewatered sludge liquors at different temperatures of TH in lab-scale. WAS was thermally hydrolyzed in temperature range of 130–170 °C for 30 min to determine its biomethane potential (BMP). After BMP test, sludge was dewatered and sludge liquor was aerated in Zahn-Wellens test to determine its non-biodegradable soluble COD known as refractory soluble COD (sCODref). With increasing temperature in the range of 130–170 °C, BMP of WAS increased by 17–27%, while sCODref increased by 3.9–8.4%. Dewaterability was also enhanced through relative increase in cake solids by 12–30%. A conversion factor was defined through mass balance to relate sCODref to volatile solids of raw WAS. Based on the conversion factor, expected increase in effluent CODs of six WWTPs in Berlin were predicted to be in the range of 2–15 mg/L after implementation of TH at different temperatures. It was concluded that with a slight decrease in temperature, formation of sCODref could be significantly reduced, while still benefiting from a substantial increase in biogas production and dewaterability improvement.
03/01/2020 00:00:00
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2.1.4 Centrifugation
Enhancing the dewaterability of anaerobically digested sludge using fibrous materials recovered from primary sludge: demonstration from a field study
Sludge dewatering is an important process for determining the operation cost of sludge disposal. Hence, improving the dewaterability of anaerobically digested sludge containing high water content is of paramount significance. For this challenge, we developed a novel process in which fibrous materials initially collected from a primary sedimentation tank, namely recovered fibers, were used as an auxiliary agent to improve the dewaterability of anaerobically digested sludge. The objective of this study was to investigate the feasibility of using the developed process to improve sludge dewaterability. Three fibrous materials individually recovered from the respective primary sedimentation tanks in different wastewater treatment plants (WWTPs) were used to investigate sludge dewaterability, organic C compositions, and calorific values. The recovered fibers showed comparable compositions irrespective of the WWTP. Six different WWTP sludge samples after anaerobic digestion were continuously supplied to three different dewatering devices, i.e., screw press, centrifuge, and belt press machines, with or without the supply of recovered fibers. Irrespective of the type of a dewatering device, the supply of recovered fibers mixed with the tested sludge samples at a feed ratio of 0.18–0.20 g-fibers/g-sludge (dry weight) reduced the amount of polymer flocculant by 13–50%, thereby displaying the superiority of the addition of recovered fibers. Furthermore, at fiber feed ratios of 0.20 g-fibers/g-sludge and 0.40 g-fibers/g-sludge when the rates of sludge supply and polymer flocculant were kept constant, the corresponding water contents in the dewatered sludge cakes decreased to about 74–76% and 69–72%, respectively. The consistent results regardless of the dewatering device or sludge sample showed the significance of the addition of recovered fibers for improvement in sludge dewaterability.
04/24/2019 00:00:00
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2.1.5 Centrifugation
Experimental analysis of centrifugal dewatering process of polyelectrolyte flocculated waste activated sludge.
The study experimentally investigated the centrifugal separation of moisture from activated sludge subject to cationic polyelectrolyte flocculation. An arm-suspended centrifuge was employed which allowed in-situ detection on all positions of interfaces of centrifuged sludge as functions of time. Experimental results revealed that, sludge flocculation would yield a significant sedimentation effect at the first phase of centrifugation. Therefore, not as suggested in conventional centrifugal-filtration models, the most significant moisture-removal stages included filtrate to flow through a wet cake. Moreover, an optimal rotational speed exists at which the moisture-removal rate reaches a maximum value. New theories/correlations are required to describe centrifugation dewatering of polyelectrolyte flocculated sludge.
07/01/2001 00:00:00
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2.1.6 Centrifugation
Experimental Study on Thermal Hydrolysis and Dewatering Characteristics of Mechanically Dewatered Sewage Sludge
After mechanical dewatering, sewage sludge has a moisture content of around 80 wt% and further disposal is required. A new sewage sludge semi-drying (dewatering) process is proposed and verified. It combines thermal hydrolysis and subsequent mechanical dewatering, with less energy consumption than traditional thermal drying. Sludge treated using this new process satisfies further disposal requirements (e.g., landfill or autothermal incineration). In the present study, a high-pressure test reactor was used to study the thermal hydrolysis of dewatered sludge. Thermally hydrolyzed sludge was subsequently dewatered by centrifugal sedimentation or by pressure filtration. The amount of organic compounds returning to the water phase was also measured. According to the results from centrifugal settling tests, the optimal thermal hydrolysis treatment temperature was 180°C. The moisture content then dropped to 1.44 kg/kg dry solids (DS; 59 wt%) after dewatering under relative centrifugal force of 9,000 × g from 5.6...
11/01/2011 00:00:00
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2.1.7 Centrifugation
HIGH EFFICIENCY DEWATERING DECANTER CENTRIFUGE TO IMPROVE DEWATERABLITY
According to a high-efficiency centrifugal dehydrator for improving dewaterability of the present invention, a single ring-shaped blocking plate is disposed between a sludge discharge port of a screw conveyor in a centrifugal dehydrator drum and a cake discharge port of the drum so that a dehydration area in the drum can be narrowed, the pressure of the screw conveyor is maximized, and dehydration efficiency can be increased. Also, the conical angle of the drum having a conical shape is adjusted to be increased so that the dehydration area is narrowed and a filtering area is lengthened, the dehydration effect is increased by raising the pressure received by the dehydration area, a filtrate treatment performance is improved, and a sludge treatment amount is increased. The ring-shaped blocking plate that is applied to the present invention is made of stainless steel, and maximizes the dehydration effect by separating a solid material from filtrate, narrowing the dehydration area, and receiving a higher pressure. The outer diameter of the blocking plate is changed by the volume ratio of the concentration of the sludge to be treated and can vary by centrifugal dehydrator model. Also, an additional suspension separation means is configured to be in the drum according to the present invention.
08/01/2014 00:00:00
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2.1.8 Centrifugation
Improve Sludge Dewatering Performance byHydrothermal Treatment
In China, over 14.3 million tons dewatered sewage sludge, with 80% water content, generated from wastewater treatment plants in 2007. Traditional technologies used by municipal solid waste treatment facilities, such as landfill, composting, incineration, are unsuitable for sludge disposal. High water content is the bottleneck of sludge treatment and disposal. Hydrothermal treatment could disrupt sludge cell and release bound water finally improve sludge dewaterability. In this paper, bench scale experiments of sludge hydrothermal treatment were carried out. Results show that under a temperature from 140∞C to 180∞C and reaction time from 15min to 90min, water content of treated sludge could reduce from 80% to about 50%. Based on laboratory parameters, a full scale project of hydrothermal process was carried out to treat 30 tons dewater sludge per day. The sludge was heated by high temperature steam generated form a boiler under 180∞C. The treated sludge was dewatered by a centrifuge. Water content of 54.66% was obtained in the full scale project.
01/01/2010 00:00:00
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2.1.9 Centrifugation
Improved Centrifuge Sludge Dewatering by Automatic Backdrive Torque Control
An investigation of different automatic torque control systems for performance optimization of solid bowl centrifuges was conducted at the Stickney Water Reclamation Plant of the Metropolitan Water Reclamation District of Greater Chicago (District). Two automatic hydraulic backdrives and a direct current automatic torque controlled backdrive were tested on centrifuges used for dewatering digested sludge conditioned with a polymer and a combination of polymer and ferric chloride. The centrifuge unit of an advanced design coupled with the direct current automatic torque controlled backdrive produced a cake having a solids content of 30% and a solids capture of 97%. The regular production unit produced a cake having a solids content of 15% and a solids capture of 85%.
12/01/1990 00:00:00
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2.1.10 Centrifugation
Movement of Sludge Through Conveyor Centrifuge
Conveyor centrifuges are widely used for dewatering wastewater sludges. The process requires that sludge be first settled out in the bowl under centrifugal acceleration and then moved by means of an internal conveyor up a beach and out of the machine. The movement of the sludge in the machine has never been observed, and its true path is unknown. The objective of this paper is to present three possible paths for the sludge in a centrifuge and to suggest the most likely mode of movement. The eventual determination of the true path will have implications for design and future development of centrifugal dewatering practice.
08/01/1988 00:00:00
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2.2 Freeze thaw

0

Freeze–thaw conditioning of water and wastewater sludges is known to be an effective and economical means of promoting dewatering when natural freezing is employed. When sludge freezes, both the suspended and dissolved solids are rejected by the growing ice front. Particles trapped in ice are known to have a very thin layer of water surrounding them and this water does not freeze at normal temperatures. Dissolved solids are thought to accumulate in this layer, causing an increase in the ionic strength of the water. This may cause compression of the double layer, leading to neutralization of repulsive forces, thus promoting aggregation. [\[link\]](https://www-nrcresearchpress-com.vu-nl.idm.oclc.org/doi/abs/10.1139/l91-130?journalCode=cjce#.XtYS8jr7SUk) **Highlights:** * a pilot-scale **sludge freezing bed** was constructed \[...\] This bed was operated for the next three years using both **anaerobically and aerobically digested sludges.** Results indicate that both sludges were **effectively dewatered** by this process. \[...\] The final **solid contents were 39.3% and 24.5%** for anaerobically digested and aerobically digested sludges respectively.[ \[Art. #ARTNUM\]](#article-96047-2004814075) * **Freeze–thaw conditioning of RBC (Rotating Biological Contactor) sludge** was tested using a pilot-scale freezing bed placed in a mobile freezer operated at −10°C. \[...\] The final **cake solids concentration was 21%**. \[...\] The results of this study showed that **freeze-thaw technology** successfully dewatered RBC sludge without the need for mechanical equipment, and is a sustainable option for **sludge dewatering in cold and remote regions**. [\[Art. #ARTNUM\]](#article-96047-2334156641) * To **improve its mechanical dewaterability**, sewage sludge is **frozen and then re-thawed.** The freezing process damages the cell walls of the micro-organisms in the sludge with the result that draining the water contained in said cells during a subsequent mechanical dewatering treatment on the thawed sludge is facilitated. \[...\] To implement the process, mechanically pre-dewatered sludge is either frozen in a **fluidised bed or placed on a conveyor belt** for freezing and thawing.[ \[Art. #ARTNUM\]](#article-96047-2840095570)

2.2.1 Freeze thaw
Freeze-thaw treatment of RBC sludge from a remote mining exploration facility in subarctic Canada.
Freeze–thaw conditioning of RBC (Rotating Biological Contactor) sludge was tested using a pilot-scale freezing bed placed in a mobile freezer operated at −10°C. Sludge samples from a remote mining exploration facility were flown in every 2 weeks, and added to the freezing bed in 8 layers of 10 cm thick. Approximately 4 months after the first layer of sludge was added, the pilot unit was removed from the freezer and thawed at ambient temperatures. After one day of thawing, the solids concentration increased from 2.6% to 16.2%. The final cake solids concentration was 21%. Melt water had increasing turbidity, COD, TSS, VSS, nitrogen and phosphorus concentrations during the thawing period. Freeze–thaw conditioning also decreased the initial densities of fecal coliforms and Salmonella in sludge. The results of this study showed that freeze-thaw technology successfully dewatered RBC sludge without the need for mechanical equipment, and is a sustainable option for sludge dewatering in cold and remote regions.
03/01/2011 00:00:00
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2.2.2 Freeze thaw
Pilot-scale studies of sludge dewatering in a freezing bed
In 1986, a pilot-scale sludge freezing bed was constructed at the U.S. Army Cold Regions Research and Engineering Laboratory in Hanover, New Hampshire, U.S.A. This bed was operated for the next three years using both anaerobically and aerobically digested sludges. Results indicate that both sludges were effectively dewatered by this process. The maximum depth of sludge frozen during this study was 1.14 m. The final solid contents were 39.3% and 24.5% for anaerobically digested and aerobically digested sludges respectively. The quality of the meltwater from the bed was similar to raw wastewater. The actual depth of sludge frozen and thawed in the bed during each year of operation was very close to that predicted by design models. Operational experience demonstrated the importance of a sand layer at the bottom of the bed for adequate drainage. Also, odors developed when the meltwater was allowed to accumulate in the bed. Odors were not a problem when the meltwater was drained away as quickly as it formed. B...
08/01/1991 00:00:00
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2.2.3 Freeze thaw
Process and device for improving the mechanical dewaterabili ty of sewage sludge
To improve its mechanical dewaterability, sewage sludge is frozen and then re-thawed. The freezing process damages the cell walls of the micro-organisms in the sludge with the result that draining the water contained in said cells during a subsequent mechanical dewatering treatment on the thawed sludge is facilitated. The process can be run continously and the cooling power of a cooling power of a cooling machine is used for freezing and its dissipated heat for thawing. To implement the process, mechanically pre-dewatered sludge is either frozen in a fluidised bed or placed on a conveyor belt for freezing and thawing.
11/07/1996 00:00:00
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2.3 Flotation methods

0

Flotation process is induced by bubbles generated from air or gas transformation within a solid-liquid suspension, the bubbles adhere to the particles to be separated carrying them at the top of the separator where they are collected. [\[link\]](https://www.frontiersin.org/articles/10.3389/fpls.2016.00113/full) **Highlights:** * This paper presents the improvement of acidification on the **dewaterability of oily sludge** from a **flotation process.** \[...\] This study verifies that the floc skeleton of oily sludge can be broken through the dissolution of aluminum hydroxide; i.e., acidification enhances the dewaterability of oily sludge by changing the floc structure.[ \[Art. #ARTNUM\]](#article-96411-2099626764) * Harvesting of oleaginous **marine microalgae by dewatering** is an important step for cost-effective algal biomass feedstock production. This paper reports separation of marine microalgae ( Tetraselmis sp. M8) from aqueous medium by **froth flotation** using various collectors (surfactants) with equal carbon chain length, such as dodecyl pyridinium chloride (DPC), N-dodecylpropane-1,3-diamine hydrochloride (DN2), dodecyl amine hydrochloride (DAH), and sodium dodecyl sulphate (SDS), at different pHs. \[...\] Use of DPC at 15 ppm in pilot-scale Jameson cell flotation tests for M8 after outdoor cultivation led to a **23-fold increase in algal concentration with over 99% algal recovery.**[ \[Art. #ARTNUM\]](#article-96411-1885468025) * The objective of this study is to examine the effect of the coagulation and homogenization in bulking sludge thickening of paper manufacturing plant using **DAF (Dissolved Air Flotation)** and gravitational sedimentation. \[...\] When anion polymer coagulant of 0.5 mg/l was added in DAF process, **water content of sludge was decreased from 96.6% to 90.7% in dewatering process** using Buchner funnel test device. [\[Art. #ARTNUM\]](#article-96411-1969600952) * In order to study the dewatering characteristics and efficiency of **thickening low concentration excess sludge** by **Cavitation Air Floatation(CAF)** \[...\] When the thickening sludge is dewatered directly by the sludge pressafiner, the solid content ratio of dewatering sludge is up to 22.4\~23.8%. Comparing with that of dewatering sludge by **integrated thicken-dewater machine** of 20.5\~22.2%, the dewatering characteristics of CAF is better, and the solid content ratio of dewatering sludge is higher. [\[Art. #ARTNUM\]](#article-96411-2161869435)

2.3.1 Flotation methods
Effect of Coagulation and Homogenization on the Dissolved Air Flotation and Sedimentation of Bulking Sludge
The objective of this study is to examine the effect of the coagulation and homogenization in bulking sludge thickening of paper manufacturing plant using DAF(Dissolved Air Flotation) and gravitational sedimentation. The effects of parameters such as dosage of coagulant and homogenization time were examined. The results showed that DAF and sedimentation was affected aluminum sulfate and anion polymer coagulant differently. At the optimum dosage of aluminum sulfate, thickening efficiency of DAF and sedimentation process were increase 1.25 time and 2.02 time, respectively. At the optimum dosage of anion polymer coagulant, thickening efficiency of DAF process was increase 1.35 time, but thickening efficiency at sedimentation was 1.06 time. When anion polymer coagulant of 0.5 mg/l was added in DAF process, water content of sludge was decreased from 96.6% to 90.7% in dewatering process using Buchner funnel test device. After homogenization(20500 rpm, 10 min), Sauter mean diameter of sludge floc was decreased from 631 to 427 , however increase of flotation efficiency by DAF was only 1.09 time.
02/28/2007 00:00:00
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2.3.2 Flotation methods
Effects of Surfactant Addition on Dewatering of Alum Sludges
In Taiwan, surfactants are frequently used in the flotation process to aid in solid/liquid separation. Their effect on the dewatering of alum sludge was investigated. Various amounts of cationic and anionic surfactants were added to sludge samples, and the dewatering characteristics of the sludge and the water content of sludge cakes were evaluated. Both surfactants improved the dewatering of the sludge by lowering the specific resistance to filtration, decreasing the bound water content, and increasing the dewatering rate of the sludge. Different combinations of anionic and cationic surfactants and polyelectrolytes were also experimented on to study the effect of surfactant addition on the dewatering characteristics of polyelectrolyte-conditioned sludge. Experimental results indicated that both cationic and anionic surfactants adversely affected the dewatering of the conditioned sludge. The addition of surfactant to the oppositely charged polyelectrolyte proved to be most detrimental to sludge dewatering...
12/01/2002 00:00:00
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2.3.3 Flotation methods
Flotation separation of marine microalgae from aqueous medium
Abstract Harvesting of oleaginous marine microalgae by dewatering is an important step for cost-effective algal biomass feedstock production. This paper reports separation of marine microalgae ( Tetraselmis sp. M8) from aqueous medium by froth flotation using various collectors (surfactants) with equal carbon chain length, such as dodecyl pyridinium chloride (DPC), N-dodecylpropane-1,3-diamine hydrochloride (DN2), dodecyl amine hydrochloride (DAH), and sodium dodecyl sulphate (SDS), at different pHs. Algal hydrophobicity, froth stability, and surfactant precipitation were characterised. The laboratory-scale mechanical flotation tests showed that at natural pH 9.5 and a lower pH, DPC outperformed DAH, DN2 and SDS in separating Tetraselmis sp. M8 from seawater. DPC was capable of rendering the microalgae hydrophobic, producing metastable froth, and dissolving readily in water, which are all desirable features of a collector for flotation separation of microalgae from water. Use of DPC at 15 ppm in pilot-scale Jameson cell flotation tests for M8 after outdoor cultivation led to a 23-fold increase in algal concentration with over 99% algal recovery.
12/01/2015 00:00:00
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2.3.4 Flotation methods
Improvement of acidification on dewaterability of oily sludge from flotation
This paper presents the improvement of acidification on the dewaterability of oily sludge from a flotation process. Various parameters, including the volume of supernatant water, capillary suction time (CST), and specific resistance to filtration (SRF) were used to evaluate the dewaterability of oily sludge. In addition, floc size distribution and release rates of Al(III) were used to explain skeleton breakage as a result of the acidification treatment. Results show that dewaterability increased obviously as the sludge pH decreased. After 120 min of settling, the volume of supernatant water reached 77% at pH 4.0. Maximum reductions in CST and SRF were 93.1% and 89.2%, respectively. Following acidification, the flocs in the oily sludge achieved a broader particle size distribution and a smaller median diameter [d (0.5)] of 36.0 μm (cf. 74.4 μm for the raw sample). In addition, lower pH led to a greater rate of release of Al(III). This study verifies that the floc skeleton of oily sludge can be broken through the dissolution of aluminum hydroxide; i.e., acidification enhances the dewaterability of oily sludge by changing the floc structure. All results indicate that acidification is advisable as a pretreatment of oily sludge.
04/01/2011 00:00:00
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2.3.5 Flotation methods
Improvement of Activated Sludge Dewaterability by Electro-flotation
Electro-flotation(EF), a novel sludge thickening method, could improve the dewaterability of activated sludge. The gas(microbubbles) generated during EF decreased the solid-liquid separation time below 1/5 of the time required for gravity sedimentation. In addition, over 90% of the sludge volume reduction could be achieved by EF although the settling characteristics of the sludge was very poor. The SRF(specific resistance to filtration) of the thickened sludge by EF was much lower than that of the sludge thickened by gravity sedimentation. The SRF of the thickened sludge decreased exponentially with increase of gas generation rate of the EF system. Gas generation rate could be controlled by varying the current density of the electrode. Degasing of the microbubbles by vigorous mixing of the thickened sludge layer deteriorated the dewaterability of the sludge. Therefore, it is obvious that the gas bubbles entrapped in the thickened sludge play a key role in the observed dewaterability improvement.
01/01/2006 00:00:00
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2.3.6 Flotation methods
Study on the Dewatering Characteristics and Efficiency of Thickening Low Concentration Excess Sludge by Cavitation Air Floatation (CAF)
In order to study the dewatering characteristics and efficiency of thickening low concentration excess sludge by Cavitation Air Floatation(CAF), As CAF-5 is employed to thicken low concentration excess sludge in Chaoyangzhou WWPT, the influent flow is 5m3/h, the sludge concentration is 4g/L, the dosage of flocculant FO4440SH is 1.0kg/tDS and the dosage of surfactant 1227 is 0.2kg/tDS, the solid content ratio of thickening sludge is 6~7%, the sludge specific resistance to filtration is 2~2.5×1012m/kg. When the thickening sludge is dewatered directly by the sludge pressafiner, the solid content ratio of dewatering sludge is up to 22.4~23.8%. Comparing with that of dewatering sludge by integrated thicken-dewater machine of 20.5~22.2%, the dewatering characteristics of CAF is better, and the solid content ratio of dewatering sludge is higher.
01/01/2011 00:00:00
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2.4 Fluidized bed

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A fluidized bed is a physical phenomenon occurring when a quantity of a solid particulate substance (usually present in a holding vessel) is placed under appropriate conditions to cause a solid/fluid mixture to behave as a fluid. Fluidized beds are used for several purposes, such as fluidized bed reactors (types of chemical reactors), **solids separation**, fluid catalytic cracking, fluidized bed combustion, heat or mass transfer or interface modification, such as applying a coating onto solid items. [\[link\]](https://en.wikipedia.org/wiki/Fluidized_bed) **Highlights:** * A pilot-scale test of **Pelleting Fluidized Bed (PFB)** process was carried out to treat wastewater of the Meilin Water Plant in Shenzhen City. The experimental results show that the PFB process, which is characterized with **good sludge thickening performance and dewaterability**, high sludge concentration, and good effluent quality, can be well used to treat wastewater from the water plant in Shenzhen City.[ \[Art. #ARTNUM\]](#article-96278-2373278101)

2.4.1 Fluidized bed
Research on Pelleting Fluidized Bed Technology for Treating Wastewater from Meilin Water Plant in Shenzhen City
A pilot-scale test of Pelleting Fluidized Bed (PFB) process was carried out to treat wastewater of the Meilin Water Plant in Shenzhen City.The experimental results show that the PFB process,which is characterized with good sludge thickening performance and dewaterability,high sludge concentration,and good effluent quality,can be well used to treat wastewater from the water plant in Shenzhen City.Under the experimental condition,sludge settling speed can be enhanced from 0.01(mm/s) to 5 mm/s,and sludge concentration can be enhanced from 5 g/L to 30 g/L.Specific resistance of sludge can be reduced to a value below 5×10~(11) m/kg and the sludge can be directly dewatered.The effluent turbidity is below 10 NTU,chroma 20-28 times and pH 7.5-8.0,reaching Ⅱ-class criteria specified in Water Quality Standard for Drinking Water Source.
01/01/2006 00:00:00
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3. Electrokinetics

Back

Electrohydrodynamics (EHD), also known as electro-fluid-dynamics (EFD) or electrokinetics, is the study of the dynamics of electrically charged fluids. [\[link\]](https://en.wikipedia.org/wiki/Electrohydrodynamics)


3.1 Electro-dewatering

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Electrodewatering is a technique in which pressure dewatering is combined with electrokinetic effects to realize an improved solid/liquid separation and hence increased filter cake dry matter contents.[ \[Art. #ARTNUM\]](#article-96006-2005699518) Enhanced electrokinetic dewatering techniques include systems based on electroosmosis, electromigration and electrophoresis principles. [\[link\]](https://scholar.google.com/scholar?as_sdt=0%2C5&btnG=&hl=en&inst=4393003693960974403&q=Harvesting%2C%20Thickening%20and%20Dewatering%20Microalgae%20Biomass) **Highlights:** * **Gravity-thickened sludge (GTS)** and **anaerobically-digested sludge (ADS)** from a wastewater treatment plant and **sludge from drying bed (DBS)** from a water treatment plant were dewatered using the pilot-scale **electro-osmotic belt filter press (EBFP)**. The results indicated that the **addition of electro-osmosis** greatly **improved sludge dewaterability,** lowering water content (WC) and heavy metal concentration, and increasing heating value. \[...\] Therefore, EBFP would produce a proper cake WC by simply controlling the current density, depending on the destination of dewatered cake such as **land application, compost, or incineration.**[ \[Art. #ARTNUM\]](#article-96006-1801256887) * **Electro-dewatering (EDW)** is an alternative emerging and **energy-efficient technology** that provides **improved liquid/solids separations** in the **dewatering of wastewater sludge**. The EDW technology is not only an innovative dewatering method for significantly reducing the volume of wastewater sludge before re-utilization or disposal, but is also a promising emerging method which may potentially be used for **decontamination** purposes. In this study, the influence of the sludge properties (e.g. electrical conductivity, zeta potential, specific cake resistance, among others) on their mechanical and electrical behaviour in terms of dewaterability and electro-dewaterability, the applied current (current density from 20 to 80 A/m 2 ), and filter cloth position relative to the electrode was investigated.[ \[Art. #ARTNUM\]](#article-96006-2767856657) * The **pressure-driven electro-dewatering (EDW)** of sewage sludge was assessed using a lab device. \[...\] The test results show that the EDW treatment enabled to dewater the sludge samples to a **dry solids content of** **18.4–31.1%** (wt%), which means **2.0–12.7% improvement** as compared to the conventional mechanical dewatering treatment used in these WWTPs. A follow-up test was carried out with the sample giving the best dewatering performance. A **dry solids content of 39.3% (wt%)** was achieved. \[...\] The **energy consumption** and sludge treatment cost associated with the EDW process were compared with the reference case (the corresponding WWTP currently operating with mechanical dewatering line). It was found that for the best performance case, technology upgrade from the conventional mechanical dewatering to the **EDW dewatering** will enable the WWTP to **reduce** its sludge management **cost up to 35% per year**.[ \[Art. #ARTNUM\]](#article-96006-2767836018) * \[...\] a bench- and pilot-scale diaphragm **filter press suited for electrodewatering** were constructed for treatment of sewage and other types of sludges. It was shown that **electrodewatering of sludge is a feasible technique**, especially for **biological sludge** types. Other types of sludge are less suited for electrodewatering because of the restricted improvements that can be realized in cake dry matter content and the high electric energy consumption. Furthermore, it was shown in pilot-scale tests that the use of a diaphragm filter press with electrodewatering facilities was very well suited to deliver dry filter cakes of sewage sludge at a **moderate energy consumption**. [\[Art. #ARTNUM\]](#article-96006-2005699518) * We investigated the change in sludge dewaterability after the addition of **fly ash** to municipal digested sludge, dewatering of which is difficult because of its high organic content. The performance of the dewatering is compared with that of **electroosmotic dewatering (EDW)** and conventional mechanical dewatering (CMD). \[...\] When sludge was dewatered using an **electroosmotic dewatering** method, the dewatering efficiency is improved about **40%** by **adding fly ash** of 25–75 μm particle size with 20 wt% when compared with conventional mechanical dewatering method without adding the fly ash. [\[Art. #ARTNUM\]](#article-96006-2071674155) * In this work, a device and a process for **dewatering offshore grown biomass** of the green **macroalgae** Ulva sp. using high-voltage **pulsed electric fields (PEF)** was developed. Ulva sp. was cultivated attached to fish cages 15km offshore. Increasing the applied voltage from 250V to 500V and invested PEF energy from 9.3±0.4 J g-1FW to 54.6±0.2Jg-1FW **increased the extracted water** from 0.033±0.006gWater g-1FW to 0.150±0.031gWater g-1FW. \[...\] PEF leads to biomass compression of 8.45±1.72% for 250V protocol and 25.66±2.53% for 500V protocol. In addition, PEF leads to the reduction of water diffusivity of 18-19% in the treated biomass, reducing air drying kinetics. [\[Art. #ARTNUM\]](#article-96006-2978757633)

3.1.1 Electro-dewatering
A comparative study of electro-dewatering process performance for activated and digested wastewater sludge
Abstract Electro-dewatering (EDW) is an alternative emerging and energy-efficient technology that provides improved liquid/solids separations in the dewatering of wastewater sludge. The EDW technology is not only an innovative dewatering method for significantly reducing the volume of wastewater sludge before re-utilization or disposal, but is also a promising emerging method which may potentially be used for decontamination purposes. In this study, the influence of the sludge properties (e.g. electrical conductivity, zeta potential, specific cake resistance, among others) on their mechanical and electrical behaviour in terms of dewaterability and electro-dewaterability, the applied current (current density from 20 to 80 A/m 2 ), and filter cloth position relative to the electrode was investigated. A two-sided filter press at lab-scale with moving anode was used, and the treatment performance of the EDW process on two different types of wastewater sludge (activated and digested) was thoroughly assessed from both an electrochemical viewpoint and in terms of the dewatering rate. The results showed that the conditioned digested sludge was more easily dewatered by mechanical dewatering (MDW) with 34–35% (w%) of dry solids content compared to 19–20% (w%) for the activated sludge, thanks to the lower content of both the microbial extracellular polymeric substances (EPS) and the volatile suspended solids fraction. For the EDW results, the electrical conductivity of the sludge was pivotal to the dryness of the final solids and therefore also to the dewatering kinetics. The results demonstrated that the activated sludge arrived at an equilibrium much faster (after approximately 3600 s) compared with digested sludge, thanks to its lower electrical conductivity (0.8 mS/cm) providing a greater voltage drop across the cathode and therefore more repulsion of the solids from the cathode leading to continuously high filtrate flowrate. Also the EDW performance was analysed by comparing the ratio of the filtrate volume collected at the anode to the volume collected at the cathode side. For digested sludge at 5 bar, 40 A/m 2 different positions of the filter cloth were tested but these configurations barely impacted the EDW performance, despite having a significant impact on the energy requirements. At industrial scale, it would be useful to position the filter cloths at some distance from the electrodes, but this study shows that this benefit may be quickly outweighed by the loss in EDW energy efficiency.
02/01/2018 00:00:00
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3.1.2 Electro-dewatering
Assessment of pressure-driven electro-dewatering as a single-stage treatment for stabilized sewage sludge
Abstract The pressure-driven electro-dewatering (EDW) of sewage sludge was assessed using a lab device. The sludge samples were supplied from four different Wastewater Treatment Plants (WWTPs) around the metropolitan area of Milan (Italy), including both aerobically and anaerobically stabilised samples. The test results show that the EDW treatment enabled to dewater the sludge samples to a dry solids content of 18.4–31.1% (wt%), which means 2.0–12.7% improvement as compared to the conventional mechanical dewatering treatment used in these WWTPs. A follow-up test was carried out with the sample giving the best dewatering performance. A dry solids content of 39.3% (wt%) was achieved. Apart from the technological performance, the economic feasibility of EDW was evaluated. The energy consumption and sludge treatment cost associated with the EDW process were compared with the reference case (the corresponding WWTP currently operating with mechanical dewatering line). It was found that for the best performance case, technology upgrade from the conventional mechanical dewatering to the EDW dewatering will enable the WWTP to reduce its sludge management cost up to 35% per year.
12/01/2017 00:00:00
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3.1.3 Electro-dewatering
Bench- and pilot-scale sludge electrodewatering in a diaphragm filter press
Electrodewatering is a technique in which pressure dewatering is combined with electrokinetic effects to realize an improved solid/liquid separation and hence increased filter cake dry matter contents. In order to be energy efficient, it is shown that sludge should be dewatered by pressure dewatering to a high extent prior to electric field application, and a sufficient contact time for the electric field must be guaranteed. In order to realize these goals, a bench- and pilot-scale diaphragm filter press suited for electrodewatering were constructed for treatment of sewage and other types of sludges. It was shown that electrodewatering of sludge is a feasible technique, especially for biological sludge types. Other types of sludge are less suited for electrodewatering because of the restricted improvements that can be realized in cake dry matter content and the high electric energy consumption. Furthermore, it was shown in pilot-scale tests that the use of a diaphragm filter press with electrodewatering facilities was very well suited to deliver dry filter cakes of sewage sludge at a moderate energy consumption. Depending on local market prices for investment, operating and sludge disposal costs, this technology may therefore lead to important savings in the sludge management process.
08/01/2006 00:00:00
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3.1.4 Electro-dewatering
Electroosmotically Enhanced Sludge Pressure Filtration.
Wastewater sludge is routinely dewatered to lower the cost of transportation and disposal. Dewatering is achieved via vacuum filtration, centrifugation, sand beds, and belt filter presses. Electroosmosis, the movement of water in the influence of a direct-current (dc) electric field, has been used since the 1930s to dewater soil for construction purposes. This study examines dewatering anaerobically and aerobically digested municipal wastewater solids with applied direct pressure and constant voltage direct current. A pressure filtration apparatus, consisting of a piston and drain plate made of conductive material encased in a body of nonconductive material, was used to apply constant pressure and constant voltage (variable current) during the experiments. Three experimental series were conducted evaluating the effect of polymer dosage and voltage on the final cake total solids ; the relationship among pressure, voltage, time, and final cake total solids ; and the relationship among initial feed solids and final cake total solids after electroosmotic filtration. Results show that final cake solids were increased to as much as 50% with 60 V dc applied. Final cake solids may be enhanced by increasing pressure, voltage, or time, and additional water may be removed from a conventionally dewatered cake by further application of dc voltage.
05/01/1999 00:00:00
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3.1.5 Electro-dewatering
Energy efficient dewatering of far offshore grown green macroalgae Ulva sp. biomass with pulsed electric fields and mechanical press
Abstract Offshore macroalgae biomass production is a promising, yet challenging, pathway to provide feedstock for biorefineries. In this work, a device and a process for dewatering offshore grown biomass of the green macroalgae Ulva sp. using high-voltage pulsed electric fields (PEF) was developed. Ulva sp. was cultivated attached to fish cages 15km offshore. Increasing the applied voltage from 250V to 500V and invested PEF energy from 9.3±0.4 J g-1FW to 54.6±0.2Jg-1FW increased the extracted water from 0.033±0.006gWater g-1FW to 0.150±0.031gWater g-1FW. The energy consumption to achieve similar moisture content with air convection drying was lower by 78.73±10.41 (JgFW-1) for 250V and 339.31±48.01 (JgFW-1) for 500V, pulse duration 50µs, pulse number 50, pulse repetition frequency 3Hz. PEF leads to biomass compression of 8.45±1.72% for 250V protocol and 25.66±2.53% for 500V protocol. In addition, PEF leads to the reduction of water diffusivity of 18-19% in the treated biomass, reducing air drying kinetics.
01/01/2020 00:00:00
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3.1.6 Electro-dewatering
Improved sludge dewatering by addition of electro-osmosis to belt filter press
Gravity-thickened sludge (GTS) and anaerobically-digested sludge (ADS) from a wastewater treatment plant and sludge from drying bed (DBS) from a water treatment plant were dewatered using the pilot-scale electro-osmotic belt filter press (EBFP). The results indicated that the addition of electro-osmosis greatly improved sludge dewaterability, lowering water content (WC) and heavy metal concentration, and increasing heating value. For instance, EBFP produced 56.0% WC for GTS, 58.4% for ADS, and 69.6% for DBS when current density was 41.1, 42.1, and 17.9 A/m2, respectively, and a cationic coagulant was dosed at 0.36% on dried solid, 0.46%, and 0.19%, respectively. Without the addition of electricity, the system achieved only 74.3% WC for GTS, 72.8% for ADS, and 74.7% for DBS. Therefore, EBFP would produce a proper cake WC by simply controlling the current density, depending on the destination of dewatered cake such as land application, compost, or incineration. Key words: belt filter press, cake, electro-os...
03/01/2003 00:00:00
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3.1.7 Electro-dewatering
The effect of the addition of fly ash to municipal digested sludge on its electroosmotic dewatering
Effective handling of municipal digested sludge requires that the product cake have low water content. To this end, we investigated the change in sludge dewaterability after the addition of fly ash to municipal digested sludge, dewatering of which is difficult because of its high organic content. The performance of the dewatering is compared with that of electroosmotic dewatering (EDW) and conventional mechanical dewatering (CMD). Fly ash classified by sieving to the size of 25–75 μm and >75 μm is added to the municipal digested sludge by 10, 20, and 50 wt% by wet base. When adding fly ash particles to municipal digested sludge, dewatering efficiency improved with smaller fly ash particle size and with increase in the amount. When sludge was dewatered using an electroosmotic dewatering method, the dewatering efficiency is improved about 40% by adding fly ash of 25–75 μm particle size with 20 wt% when compared with conventional mechanical dewatering method without adding the fly ash. It is concluded that fly ash particles rich in inorganic material are helpful in the dewatering process when added to municipal digested sludge and EDW is more effective than CDW.
10/01/2011 00:00:00
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3.1.8 Electro-dewatering
The feasibility of electro-osmotic belt filter dewatering technology at pilot scale
Sewage sludge is typically dewatered using drying beds, belt filter presses or centrifuges. Mechanical dewatering of sludge is costly in terms of capital and running costs, especially the flocculent. In an attempt to address the need for more cost-effective dewatering technologies, electro-osmotic belt filtering was developed by Smollen and Kafaar in 1995. Themechanical equipment resembles a belt filter press but the belts are stainless steel, woven belts, which act as the electrodes. In this study, thefeasibility of the technology was tested at pilot scale using wasteactivated-, anaerobically digested- and dissolved air flotation sludge. The parameters which were investigated includes the applied voltage, polyelectrolyteusage and sludge feed rate. Applied voltage of between 15 and 25 volts increased the dewatering significantly in the waste activated- and anaerobically digested sludge. Applying a voltage in dissolved air flotation sludge could not enhance the efficiency of dewatering, unless stored to de-air. The technology was found as sensitive to polyelectrolyte dosages as belt presses. The performance of the electro-osmotic belt filter was sensitive to feed rate, but performed well with non-thickened waste activated sludge (0.61% solids), resulting in cake solids above 20%.
04/01/2000 00:00:00
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3.2 Electroflotation

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EF is an electrochemical version of the typically applied flotation, which presents high efficiency in promoting separation of solid from liquid phases or one liquid phase from another. In EF even the smallest particles can be separated from a liquid, due to uniform and tiny bubbles of hydrogen and oxygen generated at the electrode's surfaces during electrolysis of an aqueous solution. [\[link\]](https://www-sciencedirect-com.vu-nl.idm.oclc.org/science/article/pii/B9780128131602000043) * **Electro-flotation(EF)**, a novel **sludge thickening** method, could **improve the dewaterability of activated sludge.** The gas(microbubbles) generated during EF decreased the **solid-liquid separation** time below 1/5 of the time required for gravity sedimentation. In addition, **over 90% of the sludge volume reduction** could be achieved by EF although the settling characteristics of the sludge was very poor.[ ](#article-96411-2403184928)

3.2.1 Electroflotation
Improvement of Activated Sludge Dewaterability by Electro-flotation
Electro-flotation(EF), a novel sludge thickening method, could improve the dewaterability of activated sludge. The gas(microbubbles) generated during EF decreased the solid-liquid separation time below 1/5 of the time required for gravity sedimentation. In addition, over 90% of the sludge volume reduction could be achieved by EF although the settling characteristics of the sludge was very poor. The SRF(specific resistance to filtration) of the thickened sludge by EF was much lower than that of the sludge thickened by gravity sedimentation. The SRF of the thickened sludge decreased exponentially with increase of gas generation rate of the EF system. Gas generation rate could be controlled by varying the current density of the electrode. Degasing of the microbubbles by vigorous mixing of the thickened sludge layer deteriorated the dewaterability of the sludge. Therefore, it is obvious that the gas bubbles entrapped in the thickened sludge play a key role in the observed dewaterability improvement.
01/01/2006 00:00:00
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3.3 Electrocoagulation/electroflocculation

0

Electrocoagulation (EC), is a technique used for wastewater treatment, wash water treatment, industrial processed water, and medical treatment. [\[link\]](https://en.wikipedia.org/wiki/Electrocoagulation) Electroflocculation is a process wherein flocculating metal ions are electrolytically added to polluted water at an anode, and gas micro bubbles are released at a cathode. The flocculating metal ions adhere to pollutants in the water, increasing their size, and the gas micro bubbles capture the flocculated pollutants and float them to the surface, from where they can be easily removed. [\[link\]](https://link-springer-com.vu-nl.idm.oclc.org/referenceworkentry/10.1007%2F978-1-4419-6996-5_138#:\~:text=Introduction,are%20released%20at%20a%20cathode.) **Highlights:** * This work involves the comparison of the removal efficiency (recovery) of two marine microalgae species Chlorococcum sp. and Tetraselmis sp. by **electrocoagulation (EC)**, a technique that has not been thoroughly explored in **marine microalgae dewatering.**[ \[Art. #ARTNUM\]](#article-96326-2006647611) * In this study, the **hybrid process of electrolysis/electrocoagulation** and zero-valent iron activated persulfate oxidation (EZP) showed a significant synergetic effect in **enhancing municipal** **sludge dewaterability**, and has the potential for enhancing industrial sludge dewaterability. \[...\] Results showed that the EZP oxidation was capable to effectively disrupt the EPS, **crack the entrapped cells**, and degrade the protein-like substances, reducing the viscosity and negative zeta potential, releasing bound water inside EPS and cells and thus **improving sludge dewaterability**.[ \[Art. #ARTNUM\]](#article-96326-2409983895) * Microalgae are being developed as a source of fuels and/or chemicals. A processing challenge is **dewatering the algae**. \[...\] **Electroflocculation** appears to be a robust process. It does, however, inherently leave electrically induced trace metal flocculants in the dewatered algae. [\[Art. #ARTNUM\]](#article-96326-2122806527)

3.3.1 Electrocoagulation/electroflocculation
A parametric study of electrocoagulation as a recovery process of marine microalgae for biodiesel production.
Abstract Microalgal biomass as feedstock for biofuel production is rapidly gaining appreciation in response to the increasing petroleum prices and the upsurge in global warming concerns. However, the process of creating concentrated biomass from microalgal cultures is limited by ineffective dewatering procedures. The economics of existing culture clarification unit operations make the process of creating biomass from microalgae unattractive for biofuel development. This work involves the comparison of the removal efficiency (recovery) of two marine microalgae species Chlorococcum sp. and Tetraselmis sp. by electrocoagulation (EC), a technique that has not been thoroughly explored in marine microalgae dewatering. High recovery efficiencies were obtained of up to 99 and 98% for Tetraselmis sp. and Chlorococcum sp., respectively. The effect of culture temperature and salinity on removal efficiency was also observed. A starting temperature of 60 °C resulted in optimal recovery values of 96 and 94% for Chlorococcum sp. and Tetraselmis sp., respectively. Whereas a starting temperature of 5 °C achieved optimal recovery of only 5 and 68% for Chlorococcum sp. and Tetraselmis sp., respectively. Increased salinity of microalgae culture showed increased microalgae recovery. Salinity of 20% gave optimal microalgae recovery values of only 6 and 9% for Chlorococcum sp. and Tetraselmis sp., respectively. Zeta potential (ZP) analysis was carried out to verify and further understand the charge neutralization mechanism due to Fe 2+ cations.
10/01/2011 00:00:00
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3.3.2 Electrocoagulation/electroflocculation
Electrically dewatering microalgae
Microalgae are being developed as a source of fuels and/or chemicals. A processing challenge is dewatering the algae. Electrical approaches to dewatering include exploiting electrophoresis or electroflocculation. The reported experiments show that electrophoresis does occur but is complicated by the effects of the fluid motion. It appears that the coupling of the algal cell and the fluid can be sufficiently strong such that fluid motion effects can influence or dominate behavior. Electroflocculation appears to be a robust process. It does, however, inherently leave electrically induced trace metal flocculants in the dewatered algae.
10/01/2011 00:00:00
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3.3.3 Electrocoagulation/electroflocculation
Enhancing the sludge dewaterability by electrolysis/electrocoagulation combined with zero-valent iron activated persulfate process
Abstract Waste activated sludge (WAS) is difficult to be dewatered due to the highly water bounded in sludge flocs, and the extracellular polymeric substances (EPS) was the major factor affecting sludge dewatering performance. In this study, the hybrid process of electrolysis/electrocoagulation and zero-valent iron activated persulfate oxidation (EZP) showed a significant synergetic effect in enhancing municipal sludge dewaterability, and has the potential for enhancing industrial sludge dewaterability. The optimal dewatering conditions for municipal sludge were voltage 40 V and 4.15 g/L Na 2 S 2 O 8 when zero-valent iron induced electrodes were applied. After EZP pretreatment, the municipal sludge specific resistance to filtration (SRF) and capillary suction time (CST) decreased by 87.4% and 49.1% respectively. The effects of EZP pretreatment on zeta potential, EPS property, viscosity and dewaterability of different sludge were analyzed to unravel the underlying mechanism of sludge conditioning. Results showed that the EZP oxidation was capable to effectively disrupt the EPS, crack the entrapped cells, and degrade the protein-like substances, reducing the viscosity and negative zeta potential, releasing bound water inside EPS and cells and thus improving sludge dewaterability. According to the analysis of Three-dimensional excitation emission matrix (3D-EEM), the EZP technology greatly decomposed tryptophan and aromatic protein-like substances in EPS. Scanning electron microscope (SEM) analysis further revealed that the disrupted EPS and cells were coagulated after EZP conditioning and reinforced sludge dewatering. The preliminary economic analysis showed that the optimized EZP was economically favorable.
11/01/2016 00:00:00
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3.3.4 Electrocoagulation/electroflocculation
Performance evaluation of a bipolar electrolysis/electrocoagulation (EL/EC) reactor to enhance the sludge dewaterability
The present study aimed to evaluate the performance of a bipolar electrolysis/electrocoagulation reactor designed to enhance the sludge dewaterability. The reactor was 15 L in volume, with two series of plates used in it; Ti/RuO2 plates for the electrolysis of the sludge, and also aluminum and iron plates for electrocoagulation process. The dewaterability of the sludge was determined in terms of its capillary suction time (CST) and specific resistance to filtration (SRF), while the degree of sludge disintegration was determined based on the value of degree of sludge disintegration (DDSCOD). The maximum reduction in CST and SRF was observed at a detention time of 20 min and a voltage of 30 V. However, increasing of both detention time and voltage significantly increased the values of CST and SRF even to an extent that they both exceeded those of the untreated sludge. The optimal degree of sludge disintegration achieved by the present study was 2.5%, which was also achieved at a detention time of 20 min and a voltage of 30 V. As reported previously, increased DDSCOD values led to increasing CST and SRF values, due primarily to the disruption of the sludge flocs. According to the results from the present study, it can be concluded that simultaneous application of electrocoagulation and electrolysis is effective in enhancing the sludge dewaterability, because electrocoagulation helps to achieve a higher degree of sludge disintegration while maintaining the desired sludge dewaterability.
01/01/2013 00:00:00
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4. Radiation

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Radiation is the emission or transmission of energy in the form of waves or particles through space or through a material medium. [\[link\]](https://en.wikipedia.org/wiki/Radiation#:\~:text=In%20physics%2C%20radiation%20is%20the,%2C%20and%20gamma%20radiation%20(%CE%B3))


4.1 Ultrasonication

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Sonication is the act of applying sound energy to agitate particles in a sample, for various purposes such as the extraction of multiple compounds from plants, microalgae and seaweeds. Ultrasonic frequencies (>20 kHz) are usually used, leading to the process also being known as ultrasonication or ultra-sonication. [\[link\]](https://en.wikipedia.org/wiki/Sonication) **Highlights:** * The **high-power ultrasound approach** seemed to be particularly effective. The mechanisms involved include atomization, microstructural effects, cavitation, and the sponge effect, which work to reduce both internal and external resistances. Applied in the right way, ultrasound could become a very effective way to **enhance mechanical dewatering.**[ \[Art. #ARTNUM\]](#article-95998-2773163778) * This research intended to study the efficiency of **ultrasound in dewatering biological sludge** in wastewater treatment plants under different conditions. In this study, response surface method was used to investigate results and optimum conditions were determined. \[...\] Results of the experiments showed that, the **ultrasonic method significantly increases the SRF**. Also based on response surface method, the best performance of ultrasonic application in sludge treatment is achievable at the following conditions: 625 W ultrasound power, 2.7 L sample volume and 13 min ultrasonic exposure duration. [\[Art. #ARTNUM\]](#article-95998-2591698800)

4.1.1 Ultrasonication
Dewatering Excess Sludges of Sanitary Sewage by Supersound and PAFC
This experiment adopted supersound and polymeric aluminum ferric chloride (PAFC) dewatering excess sludges. Firstly, aluminum chloride and ferric chloride were synthetized to a novel inorganic flocculant ——PAFC and the optimal molar ratio of A1 and Fe was 7:3. Secondly, PAFC singly dewatered excess sludges. The optimum technological conditionwas the optimum dosage of 120mg/L and pH of 8. As a result , the sludge water content decreased from 87.48% to 70.87%. Thirdly, supersound singly dewatered excess sludges. The optimum technological condition was the optimum power of 150W and time of 2.5min. Lastly, the combination of supersound and PAFC sludge dewatered excess sludges and moisture content was reduced to 70.01%.
08/01/2013 00:00:00
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4.1.2 Ultrasonication
Enhanced sludge dewatering based on the application of high-power ultrasonic vibration
Abstract Interest in producing heat and power using municipal wastewater sewage sludge as a fuel is increasing worldwide. Since its water content is initially high, sludge must be dewatered and further dried if it is to serve as an effective fuel for combustion. However, to maximize net energy production, the drying processes must use as little energy as possible. The water content in sewage sludge comprises both unbound and bound water. Unbound water content is typically extracted using a number of mechanical dewatering techniques. In terms of total solids content (TS), dewatering processes can take sludge from an initial 3–5% to a more solid 25–45% TS with minimal energy expenditure. However, this level of dryness is not sufficient for effective combustion. To produce an effective fuel, TS levels must be increased. Achieving high level of dryness involves removing any remaining unbound water and substantial bound water content as well. Heat is normally applied to accomplish this by changing the phase of the water from liquid to vapor. Although dewatering is energy-efficient, thermal drying is not. The energy used to thermally dry sludge can be two orders of magnitude greater than the energy used for dewatering. Therefore, to expend as little energy as possible to achieve the needed dryness, conventional dewatering processes clearly must be improved. This paper describes work carried out to identify promising ways to efficiently enhance the dewatering and drying of sewage sludge. Available dewatering approaches were reviewed and experiments were carried out to examine the relative effects of temperature, atmospheric pressure, and high-power ultrasound. The high-power ultrasound approach seemed to be particularly effective. The mechanisms involved include atomization, microstructural effects, cavitation, and the sponge effect, which work to reduce both internal and external resistances. Applied in the right way, ultrasound could become a very effective way to enhance mechanical dewatering.
03/01/2018 00:00:00
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4.1.3 Ultrasonication
Optimization of ultrasonic waves application in municipal wastewater sludge treatment using response surface method
Abstract Today, many limitations are faced in sludge treatment and disposal. Therefore evaluation of different approaches to reduce sludge production in the activated sludge process has attracted great attention. Application of ultrasonic waves in sludge treatment caused to reduce sludge volume and accelerate sludge digestion. This research intended to study the efficiency of ultrasound in dewatering biological sludge in wastewater treatment plants under different conditions. In this study, response surface method was used to investigate results and optimum conditions were determined. Sludge was treated in different conditions as follows: 330–920 W ultrasound power, 1.5–3.9 L sample volume and 6–20 min ultrasonic exposure duration. Then, the effect of waves was studied in terms of SRF (specific resistance to filtration). Results of the experiments showed that, the ultrasonic method significantly increases the SRF. Also based on response surface method, the best performance of ultrasonic application in sludge treatment is achievable at the following conditions: 625 W ultrasound power, 2.7 L sample volume and 13 min ultrasonic exposure duration. A mathematical model for accurate prediction of SRF changes of the sludge was derived using statistical data.
05/01/2017 00:00:00
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4.2 Electron irradiation

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Electron-beam processing or electron irradiation (EBI) is a process that involves using electrons, usually of high energy, to treat an object for a variety of purposes. [\[link\]](https://en.wikipedia.org/wiki/Electron-beam_processing) **Highlights:** * a study on the **improvement** of sedimentation and **dewatering of sewage sludge by irradiation** with 60 Co gamma rays and **electron beams** was undertaken. \[...\] The necessary dose for improving the sedimentation and dewatering was observed to be 1–3 kGy for the activated sludge and 5–10 kGy for the digested sludge.[ \[Art. #ARTNUM\]](#article-96040-2051836387) * The pretreatment technology for **sludge** by using **radiation** and among diverse discarded resources were **starfish** selected as the material to manufacture the **dewatering aid.** \[...\] After the application of the condensation process, the sludge with the starfish powder added was dewatered using the **belt press and centrifuge,** which were the traditional pressure dewatering devices. As the result, it **reduced the water content of the sludge 20% higher** than the dewatered cake with no dewatering aid added and irradiation. \[...\] Based on the results saying that the dewatering aid and radiation technology can improve dewatering effects using the traditional dewatering devices, this pretreatment technology will be expected to be applied to **sewage treatment plants**. [\[Art. #ARTNUM\]](#article-96040-1662768)

4.2.1 Electron irradiation
Enhancement of Sludge Dewaterability using a Starfish and the Radiation Technology
This study was focused on the manufacturing method of a dewatering aid, which would reduce the water content of the sludge cake by enhancing the dewaterability of sewage sludge. The pretreatment technology for sludge by using radiation and among diverse discarded resources were starfish selected as the material to manufacture the dewatering aid. Starfish went through the process of washing, drying, and pulverizing. The starfish powder made in this process was applied to the digested sludge generated at the sewage treatment plant of D City, and its effects were investigated. The starfish powder that was 300 in particle size was added to the irradiated digested sludge. After the application of the condensation process, the sludge with the starfish powder added was dewatered using the belt press and centrifuge, which were the traditional pressure dewatering devices. As the result, it reduced the water content of the sludge 20% higher than the dewatered cake with no dewatering aid added and irradiation. When the powder was added, it contributed to less use of the coagulant added. The more irradiation dose, the lower water content did the dewatered cake have and the more coagulant was needed for condensation, which seems to be a disadvantage that can be compensated for by the starfish dewatering aid. A small-scaled treatment of the study to a radiation technology and dewatering aid using a discarded resource confirmed the potential of dewaterability. Based on the results saying that the dewatering aid and radiation technology can improve dewatering effects using the traditional dewatering devices, this pretreatment technology will be expected to be applied to sewage treatment plants.
01/01/2004 00:00:00
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4.2.2 Electron irradiation
Improvement of sedimentation and dewatering of municipal sludge by radiation
Abstract As the promotion of sewerage system, the volume of municipal sludge in Tokyo has increased rapidly. Due to recent changes in the properties of the sludge, moreover, it has become difficult to thicken the liquid sewage sludge by sedimentation and to dewater the thickening sludge mechanically. The development of a new effective method for sludge treatment is necessary. Therefore, a study on the improvement of sedimentation and dewatering of sewage sludge by irradiation with 60 Co gamma rays and electron beams was undertaken. Sedimentation tests and various dewatering tests were carried out for the waste activated sludge and anaerobically digested sludge. From the changes in the settling rate, capillary suction time, water content of the sludge cake, and the quality of separated water by irradiation, the optimum irradiation conditions for improving the sedimentation and dewatering of 2 types sludge were determined. The necessary dose for improving the sedimentation and dewatering was observed to be 1–3 kGy for the activated sludge and 5–10 kGy for the digested sludge. To confirm the cause of those changes by irradiation, the zeta potential and viscosity of the sludge were measured.
01/01/1990 00:00:00
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4.3 Gamma radiation

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A gamma ray, or gamma radiation (symbol γ or {\\displaystyle \\gamma }\\gamma ), is a penetrating electromagnetic radiation arising from the radioactive decay of atomic nuclei. It consists of the shortest wavelength electromagnetic waves and so imparts the highest photon energy. [\[link\]](https://en.wikipedia.org/wiki/Gamma_ray) **Highlights:** * a study on the improvement of sedimentation and **dewatering of sewage sludge by irradiation with 60 Co gamma rays** and electron beams was undertaken. \[...\] The necessary dose for improving the sedimentation and dewatering was observed to be 1–3 kGy for the activated sludge and 5–10 kGy for the digested sludge.[ \[Art. #ARTNUM\]](#article-96041-2051836387)

4.3.1 Gamma radiation
Effect of Sludge Loading on Continuous Flow Dewatering with Electromagnetic Wave
With the introduction of electromagnetic wave into the field of excess sludge dewatering,most research has been based on pilot-scale static experiments,which affects the application of this technology. A continuous flow sludge dewatering system with 2 450 MHz electromagnetic wave was used to dewater the excess sludge from Longwangzui WWTP in Wuhan. The influence of sludge loading on sludge dewaterability was investigated. The results indicated that mechanical squeezing of the peristaltic pump had no effect on sludge dewaterability. When the sludge loading was less than 100 mL,the water content and settleability of the excess sludge changed greatly. When the loading was more than 100 mL, these physical characteristics were steady. Under the continuous flow condition,application of 2 450 MHz electromagnetic wave could effectively disintegrate sludge and promote the dissolution of TN,TP and SCOD,having an obvious biological effect.
01/01/2014 00:00:00
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4.3.2 Gamma radiation
Improvement of sedimentation and dewatering of municipal sludge by radiation
Abstract As the promotion of sewerage system, the volume of municipal sludge in Tokyo has increased rapidly. Due to recent changes in the properties of the sludge, moreover, it has become difficult to thicken the liquid sewage sludge by sedimentation and to dewater the thickening sludge mechanically. The development of a new effective method for sludge treatment is necessary. Therefore, a study on the improvement of sedimentation and dewatering of sewage sludge by irradiation with 60 Co gamma rays and electron beams was undertaken. Sedimentation tests and various dewatering tests were carried out for the waste activated sludge and anaerobically digested sludge. From the changes in the settling rate, capillary suction time, water content of the sludge cake, and the quality of separated water by irradiation, the optimum irradiation conditions for improving the sedimentation and dewatering of 2 types sludge were determined. The necessary dose for improving the sedimentation and dewatering was observed to be 1–3 kGy for the activated sludge and 5–10 kGy for the digested sludge. To confirm the cause of those changes by irradiation, the zeta potential and viscosity of the sludge were measured.
01/01/1990 00:00:00
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5. Biological approaches

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Dewatering methods using biological components. 


5.1 Reed beds

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Reed beds are natural habitats found in floodplains, waterlogged depressions, and estuaries. Reed beds are part of a succession from young reeds colonising open water or wet ground through a gradation of increasingly dry ground. Artificial reed beds are used to remove pollutants from grey water. [\[link\]](https://en.wikipedia.org/wiki/Reed_bed#:\~:text=Reed%20beds%20are%20natural%20habitats,gradation%20of%20increasingly%20dry%20ground.) **Highlights:** * **Sludge treatment reed beds (STRBs)** are an environmentally friendly technology which provides **integrated dewatering and stabilization of sewage sludge**. STRBs do not require the use of chemicals to improve the dewatering process. STRB is both, a **low-emission and a low-energy-consuming method.** \[...\] Research and literature reports indicate that sewage sludge treated in STRB is dewatered, which results in an **increase in the dry matter (dm) (from 1.1% to 15.5%)** and stabilization due to the decrease in the content of the organic matter (from 71.2% of the dm to 52.4% of the dm).[ \[Art. #ARTNUM\]](#article-96015-2513958998) * The objective of the paper is to present the current experience and lessons learned from the operation and to assess the **quality of sewage sludge from STRBs** in Poland. \[...\] The average **dry matter content** in sludge treated in Polish STRBs was from **11.2 to even 53.7%**. The degree of mineralization in analyzed systems was from 31.4 to 68.6%. The average nutrient contents was for nitrogen from 1.0 to 10% DM and for phosphorus from 0.2 to 1.0% DM. The conducted research confirms that sludge treated in STRBs is **dewatered and stabilized**, thus it could be used as a **fertilizer in agriculture.** [\[Art. #ARTNUM\]](#article-96015-2810952401) * In trials at Rugeley, UK, **reed beds** were used for **dewatering agricultural sludges and slurries**. \[...\] The results showed that the planted Bed A had definitely better dewatering ability than the unplanted one fed at a similar rate.[ \[Art. #ARTNUM\]](#article-96015-2461939848)

5.1.1 Reed beds
Integrated dewatering and stabilization system as an environmentally friendly technology in sewage sludge management in Poland
Abstract Sludge treatment reed beds (STRBs) are an environmentally friendly technology which provides integrated dewatering and stabilization of sewage sludge. STRBs do not require the use of chemicals to improve the dewatering process. STRB is both, a low-emission and a low-energy-consuming method. After the stabilization process, sludge is characterized by the chemical composition similar to that of humus. The aim of the paper is to present the comprehensive data from Waste Water Treatment Plant (WWTP) in Gniewino (Poland) where the sewage sludge is dewatered and stabilized in a STRB. Research and literature reports indicate that sewage sludge treated in STRB is dewatered, which results in an increase in the dry matter (dm) (from 1.1% to 15.5%) and stabilization due to the decrease in the content of the organic matter (from 71.2% of the dm to 52.4% of the dm). Likewise, thanks to the high concentration of nutrients (TKN concentration − 3.64% of the dm and P concentration − 3.54% of the dm) and the low concentration of heavy metals (below permissible values for the agricultural use) after the time of stabilization, safe and valuable product can be recycled to the environment. Reject water (RW) generated during this process has relatively stable and much better properties in comparison to these which are generated in high technologies for sludge treatment. Thus, recycling the RW from the slugde dewatering in STRB represents a very low internal pollution and should not alert the treatment proceses of wastewater.
01/01/2017 00:00:00
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5.1.2 Reed beds
Polish experience in operation of sludge treatment reed beds
Abstract Sludge Treatment Reed Beds (STRBs) is the technology of sludge treatment, which is based on natural processes occurring in the environment, in specially designed and operated facilities to achieve benefits for the environment. Integrated dewatering and stabilization occur in reed systems. For economic and environmental reasons it is an attractive solution, especially in rural areas where there are no appropriate facilities. In the recent years many European countries like Denmark, France or Germany have applied this technology for sewage sludge management. Poland has also some experience in dewatering and stabilization of sewage sludge in STRB systems. The objective of the paper is to present the current experience and lessons learned from the operation and to assess the quality of sewage sludge from STRBs in Poland. The analyzed sewage sludge was treated in STRBs located in five wastewater treatment plants: Darzlubie, Swarzewo, Zambrow, Nadole and Gniewino, Poland. Two from the analyzed systems (Darzlubie and Swarzewo) worked only in a pilot scale and three of them (Darzlubie, Swarzewo and Nadole) did not work any longer. In the collected samples of sludge the evaluation of dewatering and stabilization processes, fertilizer properties, as well as heavy metals concentrations were determined. The average dry matter content in sludge treated in Polish STRBs was from 11.2 to even 53.7%. The degree of mineralization in analyzed systems was from 31.4 to 68.6%. The average nutrient contents was for nitrogen from 1.0 to 10% DM and for phosphorus from 0.2 to 1.0% DM. The conducted research confirms that sludge treated in STRBs is dewatered and stabilized, thus it could be used as a fertilizer in agriculture.
09/01/2018 00:00:00
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5.1.3 Reed beds
Reed bed dewatering of agricultural sludges and slurries
In trials at Rugeley, UK, reed beds were used for dewatering agricultural sludges and slurries. Three beds, each of 3.5m 2 , were employed, two planted with Phragmites australis , the third left unplanted as control. The sludge contained partly oxidised solids from a Biological Aerated Filter (BAF) treating weak pig slurry. It was supplemented with untreated settled pig slurry. Following reed establishment planted Bed A was fed at a constant similar rate to the unplanted Control Bed C. The second planted Bed B was fed at higher rates alternating with rest periods. On this bed the aeration pipes were blocked off. The trials were run for 16 months, which included two summer periods. The results showed that the planted Bed A had definitely better dewatering ability than the unplanted one fed at a similar rate. During the summer months Bed B could be fed at over twice the rate used for the constant input beds. The percolate from the control bed was more highly oxidised than from the planted beds, probably due to a longer holdup time in the absence of reeds. On Bed B the reed quality deteriorated during the second year, after use of untreated slurry as feed.
12/01/2001 00:00:00
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5.2 Bioleaching

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Bioleaching is the extraction of metals from their ores through the use of living organisms. [\[link\]](https://en.wikipedia.org/wiki/Bioleaching) **Highlights:** * **Bioleaching** with Acidithiobacilli species has been proved to be a technologically feasible process in **removing sludge-borne toxic metal and improving sludge in-deep dewatering**.This paper compared several methods for sludge in-deep dewatering and described the advantages of bioleaching technology against other physical or chemical approaches. \[...\] The results obtained from the two-year operation of the engineering project that bioleached sludge could be dewatered mechanically into semi-drying odorless khaki-colored sludge cake with the **moisture of 60% or below**. Moreover, dewatered bioleached sludge cake contained similar levels of organic matter, calorific value, N, and P to fresh sludge on dry basis, indicating that it had **good physic-chemical properties** for its consequent **reutilization such as incineration or land application.** Besides, the filtrate of bioleached sludge could be discharged into sewage treatment plant without adverse effect. [\[Art. #ARTNUM\]](#article-96246-2363643730) * A **novel joint method of bioleaching with Fenton oxidation** was applied to condition **sewage sludge.** \[...\] The specific resistance to filtration (SRF) and moisture of sludge cake (MSC) were adopted to evaluate the improvement of sludge dewaterability. After 2-day bioleaching, the sludge pH dropped to about 2.5 which satisfied the acidic condition for Fenton oxidation. Meanwhile, the SRF declined from 6.45 × 10 10 to 2.07 × 10 10  s 2 /g, and **MSC decreased from 91.42% to 87.66%**. \[...\] Under optimal conditions, SRF, volatile solids reduction, and MSC were 3.43 × 10 8  s 2 /g, 36.93%, and **79.58%**, respectively. \[...\] The sludge conditioning mechanisms by bioleaching-Fenton oxidation might mainly include the flocculation effects and the releases of extracellular polymeric substances–bound water and intercellular water. [\[Art. #ARTNUM\]](#article-96246-2007728656)

5.2.1 Bioleaching
[Improvement of municipal sewage sludge dewaterability by bioleaching: a pilot-scale study with sequence batch reaction model].
To observe the bioleaching effect on sewage sludge dewaterability,three consecutive batch bioleaching experiments were conducted through a bioleaching bio-reactor with 700 L of working volume.Subsequently,the bioleached sludge was dewatered by using chamber filter press.The results show that the 1st batch bioleaching process can be finished within 90 hours if the aeration amount was 1.2 m3/h with the 1∶15 mixing ratio of bioleached sludge to raw sludge.The pH of sludge declines from initial 6.11 to 2.33 while ORP increased from initial-134 mV to finial 507 mV.The specific resistance to filtration(SRF) of the tested sludge was decreased from original 1.00×1013m/kg to final 0.09×1013m/kg after bioleaching.For the subsequent two batch trials,the bioleaching process can be finished in 40 hours and 46 hours,respectively.Likewise,sludge SRF is also significantly decreased to 0.19×1013m/kg and 0.36×1013m/kg if the mixing ratio of bioleached sludge to fresh sludge is 1∶1 although the microbial nutrient substance dosage is reduced by 25% and 50% for 2nd and 3rd batch experiments,respectively.The harvested bioleached sludge from three batch trails is dewatered by chamber filter press with 0.3-0.4 MPa working pressure for 2 hours.It is found that the moisture of dewatered sludge cake can be reduced to 58%,and that the dewatered sludge cake is of khaki appearance and didn't emit any offensive odor.In addition,it is also observes that sludge organic matter only changed a bit from 52.9% to 48.0%,but 58% of sludge-borne Cu and 88% of sludge-borne Zn can be removed from sludge by bioleaching process.Therefore,dual goals for sludge-borne heavy metal removal and sludge dewatering of high efficiency can be achieved simultaneously through the approach mentioned above.Therefore,bioleaching technique is of great engineering application for the treatment of sewage sludge.
07/01/2011 00:00:00
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5.2.2 Bioleaching
Bioleaching role in improving sludge in-deep dewatering and removal of sludge-borne metals and its engineering application
High moisture content of and the presence of toxic metals in sewage sludge restrict,to a great extend,the disposal or recycling of sludge including landfill,incineration,and land application.Bioleaching with Acidithiobacilli species has been proved to be a technologically feasible process in removing sludge-borne toxic metal and improving sludge in-deep dewatering.This paper compared several methods for sludge in-deep dewatering and described the advantages of bioleaching technology against other physical or chemical approaches.Furthermore,the principle,technological process,and the influence factors of sludge bioleaching technology were demonstrated in details.Taking bioleaching practical engineering application project with treating sludge 200 t·d-1 located in Wuxi Lucun Sewage Treatment Plant,Wuxi City,Jiangsu Province as an example,bioleaching technique parameters and sludge treatment effect were reported.The results obtained from the two-year operation of the engineering project that bioleached sludge could be dewatered mechanically into semi-drying odorless khaki-colored sludge cake with the moisture of 60% or below.Moreover,dewatered bioleached sludge cake contained similar levels of organic matter,calorific value,N,and P to fresh sludge on dry basis,indicating that it had good physic-chemical properties for its consequent reutilization such as incineration or land application.Besides,the filtrate of bioleached sludge could be discharged into sewage treatment plant without adverse effect.It is concluded that bioleaching approach is a novel technology with an extensive application prospect.
01/01/2012 00:00:00
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5.2.3 Bioleaching
Feasibility of bioleaching combined with Fenton oxidation to improve sewage sludge dewaterability
Abstract A novel joint method of bioleaching with Fenton oxidation was applied to condition sewage sludge. The specific resistance to filtration (SRF) and moisture of sludge cake (MSC) were adopted to evaluate the improvement of sludge dewaterability. After 2-day bioleaching, the sludge pH dropped to about 2.5 which satisfied the acidic condition for Fenton oxidation. Meanwhile, the SRF declined from 6.45 × 10 10 to 2.07 × 10 10  s 2 /g, and MSC decreased from 91.42% to 87.66%. The bioleached sludge was further conditioned with Fenton oxidation. From an economical point of view, the optimal dosages of H 2 O 2 and Fe 2 + were 0.12 and 0.036 mol/L, respectively, and the optimal reaction time was 60 min. Under optimal conditions, SRF, volatile solids reduction, and MSC were 3.43 × 10 8  s 2 /g, 36.93%, and 79.58%, respectively. The stability and settleability of sewage sludge were both improved significantly. Besides, the results indicated that bioleaching-Fenton oxidation was more efficient in dewatering the sewage sludge than traditional Fenton oxidation. The sludge conditioning mechanisms by bioleaching-Fenton oxidation might mainly include the flocculation effects and the releases of extracellular polymeric substances–bound water and intercellular water.
02/01/2015 00:00:00
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6. Combinations

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Combinations of mechanical methods: two consecutive methods as examples and integraded methods as separate technologies. 


6.1 Electro Acoustic Dewatering press (EAD press)

0

The EAD press applies a combination of mechanical pressure, electrical current and ultrasonics. [\[Art. #ARTNUM\]](#article-96250-1991746824) **Highlights:** * The Department of Energy, Battelle Institute, and Ashbrook-Simon-Hartley, have jointly developed an **Electro Acoustic Dewatering press (EAD press).**  \[...\] This press is utilized after conventional dewatering devices and can **remove up to 50% water** from filtered sludge cake at a fraction of the cost incurred in existing thermal drying devices. \[...\] The EAD press has been tested successfully on a variety of materials including **apple pomace, corn gluten, sewage sludge, and coal fines**. A three week long full scale trial was conducted successfully at a pharmaceutical industry to determine the application of this technology for dewatering **waste activated sludge.** [\[Art. #ARTNUM\]](#article-96250-1991746824)

6.1.1 Electro Acoustic Dewatering press (EAD press)
Application of electro acoustics for dewatering pharmaceutical sludge
Application of electro acoustic principles for dewatering has been developed by Battelle Institute. The Department of Energy, Battelle Institute, and Ashbrook-Simon-Hartley, have jointly developed an Electro Acoustic Dewatering press (EAD press). The EAD press applies a combination of mechanical pressure, electrical current and ultrasonics. This press is utilized after conventional dewatering devices and can remove up to 50% water from filtered sludge cake at a fraction of the cost incurred in existing thermal drying devices. The dominant mechanism of sludge dewatering by EAD press is electro-osmosis due to the application of a direct current field. Electro-osmosis is caused by an electrical double layer of oppositely charged ions formed at the solid liquid interface, which is characterized by zeta potential. The ultrasonic fields help electro-osmosis by consolidation of the filter cake and by release of inaccessible liquid. The EAD press has been tested successfully on a variety of materials including apple pomace, corn gluten, sewage sludge, and coal fines. A three week long full scale trial was conducted successfully at a pharmaceutical industry to determine the application of this technology for dewatering waste activated sludge.
02/01/1992 00:00:00
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6.2 Electro-coagulation floatation (ECF)

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ECF combines the production of metal flocculant and microbubbles in-situ, using a gas-generating cathode and a metal floc-generating sacrificial anode. [\[Art. #ARTNUM\]](#article-96324-2918890548) **Highlights:** * **Electro-coagulation floatation (ECF)** is a **foam-floatation dewatering method** that has been shown to be a highly **effective, rapid, and scalable separation methodology.** In this manuscript, an in-depth analysis of the gas and flocculant levels observed during the process is provided, with microbubbles observed in the 5–80 μm size range at a concentration of 10 2 –10 3 bubbles mL −1. \[...\] ECF separated microalgal culture had an algal biomass loading of 13% and as such was ideal for direct down-stream processing through hydrothermal liquefaction. [\[Art. #ARTNUM\]](#article-96324-2918890548)

6.2.1 Electro-coagulation floatation (ECF)
Improving electrocoagulation floatation for harvesting microalgae
Abstract Electro-coagulation floatation (ECF) is a foam-floatation dewatering method that has been shown to be a highly effective, rapid, and scalable separation methodology. In this manuscript, an in-depth analysis of the gas and flocculant levels observed during the process is provided, with microbubbles observed in the 5–80 μm size range at a concentration of 10 2 –10 3 bubbles mL −1 . Electrolysis of microalgae culture was then observed, demonstrating both effective separation using aluminium electrodes (nine microalgal species tested, 1–40 μm size range, motile and non-motile, marine and freshwater), and sterilisation of culture through bleaching with inert titanium electrodes. Atomic force microscopy was used to visualise floc formation in the presence and absence of algae, showing nanoscale structures on the magnitude of 40–400 nm and entrapped microalgal cells. Improvements to aid industrial biotechnology processing were investigated: protein-doping was found to improve foam stability without inducing cell lysis, and an oxalate buffer wash regime was found to dissolve the flocculant whilst producing no observable difference in the final algal lipid or pigment profiles, leaving the cells viable at the end of the process. ECF separated microalgal culture had an algal biomass loading of 13% and as such was ideal for direct down-stream processing through hydrothermal liquefaction. High bio-crude yields were achieved, though this was reduced slightly on addition of the Al(OH) 3 after ECF, with carbon being distributed away to the aqueous and solid residue phases. The amenability and compatibility of ECF to integration with, or replacement of, existing centrifugation and settling processes suggests this process may be of significant interest to the biotechnology industry.
05/01/2019 00:00:00
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6.3 Centrifugation + filter press

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**Highlights:** * The **sludge was then dewatered** by a **centrifuge and a filter-press** on pilot scale and many tests were carried out under different operating conditions.[ \[Art. #ARTNUM\]](#article-96280-1606538359)

6.3.1 Centrifugation + filter press
Sludge dewatering in a conventional plant with phosphorus removal. I: Analysis of additional costs
Abstract The aim of this research is to assess the differences in quantity and quality of sludges produced in a conventional activated sludge plant, modified for phosphorus chemical removal. Tests were carried out at the Cesenatico sewage treatment plant, where in summer phosphorus is removed simultaneously to the biological process with the aid of aluminium or ferrous sulphate. Characteristics of the sludge produced with or without phosphorus removal were compared. The sludge was then dewatered by a centrifuge and a filter-press on pilot scale and many tests were carried out under different operating conditions. In this part, the plant's most important performances are discussed with regard to phosphorus removal efficiency, sludge production, characteristics and dewaterability. The experiments showed that phosphorus could be removed up to residual concentration of 1.6 mg 1 −1 without detrimental effects on the biological process, with an increase of sludge production of 21 and 36% using aluminium or ferrous sulphate respectively. On the basis of experimental results a costs analysis was carried out to assess the costs for phosphorus removal, including the additional ones for sludge conditioning, dewatering and cake transport to landfill. It results that additional costs vary from 3290 to 6380 Lit per capita per year (29–54%). The higher costs refer to smaller plants (50,000 inhabitants), in which aluminium sulphate is used and sludge dewatered by centrifuge. The use of ferrous rather than aluminium sulphate allows savings of 1300–1600 Lit per capita per year.
01/01/1985 00:00:00
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6.4 Flotation + filtration

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**Highlights:** * After the successes of flotation of waste-activated sludge (WAS), using the new technique utilizing CO 2 gas as well as using model gas (80% N 2 +20% CO 2 ) in previous research because of the high water solubility of CO 2 gas, the aim of this study is to develop a **simple method for dewatering WAS for easier reuse and safe disposal.** The paper introduces a laboratory model for dewatering WAS in two stages: **flotation followed by filtration**. The first stage enables recycling a mixture of greenhouse gases containing 20% of CO 2 and 80% of N 2 gases by volume. The second stage uses a simple compression cell for dewatering WAS.[ \[Art. #ARTNUM\]](#article-96413-2023225695)

6.4.1 Flotation + filtration
Dewatering waste-activated sludge using dissolved gas-flotation followed by filtration.
After the successes of flotation of waste-activated sludge (WAS), using the new technique utilizing CO 2 gas as well as using model gas (80% N 2 +20% CO 2 ) in previous research because of the high water solubility of CO 2 gas, the aim of this study is to develop a simple method for dewatering WAS for easier reuse and safe disposal. The paper introduces a laboratory model for dewatering WAS in two stages: flotation followed by filtration. The first stage enables recycling a mixture of greenhouse gases containing 20% of CO 2 and 80% of N 2 gases by volume. The second stage uses a simple compression cell for dewatering WAS. Experiments were carried out to reduce the moisture content and volume of WAS. This was executed using compression force introduced by a low value of air pressure. Using the experimental dewatering model, promising results were obtained. Furthermore, other data were obtained, such as the effect of temperature on the efficiency of dewaterability. It is hoped that the results of this study will lead to further study of collecting industrial CO 2 gas emissions from burning fossil fuels for use in wastewater treatment to decrease the resulting harmful effects of global warming.
06/01/2010 00:00:00
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6.5 Flotation + centrifugation

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**Highlights:** * The aim of this study is to develop a simple method for **dewatering waste-activated sludge (WAS)** for easier reuse and safer disposal of sludge. The paper builds on the success of a **new flotation technique** developed in previous research by the author utilizing the high water solubility of CO2 gas along with the model-gas (80%N2+20%CO2). The paper introduces a simple laboratory model for dewatering WAS in two stages, **flotation followed by centrifugation**. The first stage enables recycling a mixture of greenhouse gases containing 20% of CO2 and 80% of N2 gases by volume. The second stage uses a simple centrifuge model for dewatering WAS. [\[Art. #ARTNUM\]](#article-96276-2315162403) * \[...\] combined process of **centrifugal dewatering and dissolved air floatation** was adopted. Using the said process to treat oily sludge could obtain a high solid content with the oil and suspended matter in the filtrate effectively removed simultaneously, which met the requirement of the subsequent process for the wastewater treatment, improved the treatment efficiency, ensured stable operation of the equipment, and **realized maximal reduction of dewatered sludge** at the same time.[ \[Art. #ARTNUM\]](#article-96276-2354739050)

6.5.1 Flotation + centrifugation
Dewatering waste activated sludge using greenhouse-gas flotation followed by centrifugation.
The aim of this study is to develop a simple method for dewatering waste-activated sludge (WAS) for easier reuse and safer disposal of sludge. The paper builds on the success of a new flotation technique developed in previous research by the author utilizing the high water solubility of CO2 gas along with the model-gas (80%N2+20%CO2). The paper introduces a simple laboratory model for dewatering WAS in two stages, flotation followed by centrifugation. The first stage enables recycling a mixture of greenhouse gases containing 20% of CO2 and 80% of N2 gases by volume. The second stage uses a simple centrifuge model for dewatering WAS. Experiments were carried out to reduce the moisture content and volume of WAS. This was executed by generating low pressure using centrifugal force introduced by a simple centrifuge apparatus. Using the experimental dewatering model, promising results were obtained for dewatering WAS. Furthermore, additional data were obtained, such as the effect of temperature on the efficiency of dewater-ability. It is hoped that the results of this study will lead to more study for the efficient reuse of greenhouse gases. This can happen by collecting and recycling industrial emissions of fossil fuels then utilizing them in wastewater and sludge treatment, thereby decreasing the resulting harmful effects of these gases on global warming.
01/01/2010 00:00:00
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6.5.2 Flotation + centrifugation
Treatment of oily sludge by combined process of centrifugal dewatering and dissolved air floatation
In view of the fact that,belt filter press can′t treat oily sludge,and the suspended matter concentration of the filtrate during the course of sludge dewatering was high,a combined process of centrifugal dewatering and dissolved air floatation was adopted.Using the said process to treat oily sludge could obtain a high solid content with the oil and suspended matter in the filtrate effectively removed simultaneously,which met the requirement of the subsequent process for the wastewater treatment,improved the treatment efficiency,ensured stable operation of the equipment,and realized maximal reduction of dewatered sludge at the same time.
01/01/2012 00:00:00
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6.6 Screw press + vibration screen

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**Highlights:** * A **dewatering screw press** has a hopper, a discharge outlet, a cylindrical screen flexibly mounted to the hopper and rigidly connected to the discharge outlet, a screw mounted to rotate beginning in the hopper and ending at the discharge outlet, the screw having an outer surface contacting the cylindrical screen, and at least one vibrator mounted to the cylindrical screen. Dewatering efficiency is improved by **vibrations** that are strong near the middle of the **screen**, while reducing or eliminating vibration near the discharge end of the screen where pressure is highest and a breaking of the seal between the screw and the screen due to vibration can reduce **dewatering of sludge** near the discharge end of the screen.[ \[Art. #ARTNUM\]](#article-96513-2988183668)

6.6.1 Screw press + vibration screen
SCREW PRESS HAVING SCREEN VIBRATION
A dewatering screw press has a hopper, a discharge outlet, a cylindrical screen flexibly mounted to the hopper and rigidly connected to the discharge outlet, a screw mounted to rotate beginning in the hopper and ending at the discharge outlet, the screw having an outer surface contacting the cylindrical screen, and at least one vibrator mounted to the cylindrical screen. Dewatering efficiency is improved by vibrations that are strong near the middle of the screen, while reducing or eliminating vibration near the discharge end of the screen where pressure is highest and a breaking of the seal between the screw and the screen due to vibration can reduce dewatering of sludge near the discharge end of the screen.
09/19/2019 00:00:00
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6.7 Freeze thaw + agitation

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Mixing is the movement of fluids and solids to enhance a process result, which is accomplished by means of an agitation source. [\[link\]](https://www-sciencedirect-com.vu-nl.idm.oclc.org/science/article/pii/B9780750675109500425) **Highlights:** * Sludge dewatering processes are usually preceded by **sludge conditioning**, which **improves the sludge dewaterability.** Although sludge conditioning is most commonly achieved by the addition of chemicals, **freeze‐thaw conditioning** can also be beneficial. The most practical way of using freeze‐thaw conditioning is to dewater the sludge on a **freezing bed**. \[...\] The results indicate that **preagitation** has positive effects on freeze‐thaw conditioning of **anaerobically digested sludge.** **Agitation** intensity was found to correlate with **sludge dewaterability**, with increased agitation leading to enhanced dewaterability of freeze‐thawed sludge.[ \[Art. #ARTNUM\]](#article-96008-2082074887)

6.7.1 Freeze thaw + agitation
Effect of Preagitation on Freeze-Thaw-Conditioned Sludge Dewaterability
Sludge dewatering processes are usually preceded by sludge conditioning, which improves the sludge dewaterability. Although sludge conditioning is most commonly achieved by the addition of chemicals, freeze‐thaw conditioning can also be beneficial. The most practical way of using freeze‐thaw conditioning is to dewater the sludge on a freezing bed. When sludge is pumped from its sources to the freezing bed, it is subjected to high shear force induced by the pump and turbulent pipe flow. This shear may affect the effectiveness of freeze‐thaw conditioning. The objectives of this study are to investigate the effects of preagitation on freeze‐thaw conditioning of anaerobically digested sludge. The results indicate that preagitation has positive effects on freeze‐thaw conditioning of anaerobically digested sludge. Agitation intensity was found to correlate with sludge dewaterability, with increased agitation leading to enhanced dewaterability of freeze‐thawed sludge.
12/01/1994 00:00:00
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6.8 Electrocoagulation + electro-dewatering

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**Highlights:** * Electrocoagulation is applied to sewage sludge as a pretreatment process of an electrodewatering system to **reduce the water content of sludge generated in wastewater treatment**. \[...\] The final **water content** of sewage sludge in the **combination of both electrocoagulation and electrodewatering system** can be **reduced to 55 wt%**, as compared to 78 wt% achieved with pressure dewatering alone. The combination of electrocoagulation and electrodewatering system shows a potential to be an effective method for reducing the water content in sludge. [\[Art. #ARTNUM\]](#article-96327-2058170914)

6.8.1 Electrocoagulation + electro-dewatering
Performance evaluation of electrocoagulation and electrodewatering system for reduction of water content in sewage sludge
Electrocoagulation is applied to sewage sludge as a pretreatment process of an electrodewatering system to reduce the water content of sludge generated in wastewater treatment. The electrodewatering system, by incorporating an electric field as an additional driving force to the conventional pressure dewatering, has been evaluated as a function of an electrode material, applied voltage and filtration time. Experiments were carried out using sewage sludge with a pressure up to 392.4 kPa and applied electrical field ranging up to 120 V/cm. Mass median diameter of the sewage sludge by the effect of electrocoagulation increases from 34.7 µm to the 41.3 µm. The final water content of sewage sludge in the combination of both electrocoagulation and electrodewatering system can be reduced to 55 wt%, as compared to 78 wt% achieved with pressure dewatering alone. The combination of electrocoagulation and electrodewatering system shows a potential to be an effective method for reducing the water content in sludge.
03/01/2006 00:00:00
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6.9 Magnetic conditioning + electro-dewatering

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The use of magnetic particles, a magnetic field and electro-dewatering. **Highlights:** * **Magnetic micro-particles (MMPs) and magnetic field (MF)** were utilized as a coupling conditioning unit before dewatering activated sludge (AS) under a horizontal electric field. The removal and migration of free and bound water in AS during coupling **magnetic conditioning–horizontal electro-dewatering (CM–HED)** were determined. \[...\] The optimum dewatering conditions for CM–HED with the final water content of 89.98% were 40 V and 120 min as determined using the response surface methodology.[ \[Art. #ARTNUM\]](#article-96262-1811184677)

6.9.1 Magnetic conditioning + electro-dewatering
Migration and distribution of water and organic matter for activated sludge during coupling magnetic conditioning-horizontal electro-dewatering (CM-HED).
Abstract Magnetic micro-particles (MMPs) and magnetic field (MF) were utilized as a coupling conditioning unit before dewatering activated sludge (AS) under a horizontal electric field. The removal and migration of free and bound water in AS during coupling magnetic conditioning–horizontal electro-dewatering (CM–HED) were determined. The organic matter migration between the solid and liquid phases of AS biosolids was also analyzed. Results show that MMPs dosage and MF intensity were determined as 0.15 g/g dry solids and 0.065 T for the best dewaterability, respectively. The optimum dewatering conditions for CM–HED with the final water content of 89.98% were 40 V and 120 min as determined using the response surface methodology. MMPs conditioning could induce a slight coagulation among AS flocs, increase the particle size from 85.9 μm to 92.3 μm and decrease mass fractal dimension from 2.18 to 2.07. The MMPs-conditioned AS also showed a network-like structure, banded cells with shrunk surfaces. CM–HED process effectively reduced the free water content (FWC) and bound water content (BWC) but increased the portion of BWC in AS. The corresponding removal ratios of bound water and free water were 52.89% and 95.86% at the anode side and 46.28% and 92.75% at the cathode side, respectively. The coupling magnetic conditioning led to the largest BWC reduction of 23.14% in CM–HED process, and most of this reduction approaching 92.83% occurred during magnetic micro-particle conditioning stage. Gravity field caused the largest sludge reduction of 87.45%. During HED stage, the removal ratio of free water in AS was 63.73% at the anode side and 36.54% at the cathode side, while it was 21.9% and 10.96% for bound water, respectively. Along with water removed by CM–HED process, the organic matter in supernatant/filtrate increased, and a sharp rise occurred during HED stage. Meanwhile, the extracellular polymeric substance (EPS) contents initially decreased at MMPs–MF conditioning stage and then increased at the HED stage. Lower EPS contents in AS indicated better dewaterability. The largest reduction in the EPS content of AS at MMPs–MF conditioning stage corresponded to the largest decline in BWC. Furthermore, the protein-like substances in the supernatant/filtrate increased from 30% to 50%, whereas the fulvic acid-like and humic acid-like substances decreased from 54% to 27% at the HED stage. MMPs significantly reduced the polysaccharide and protein contents in the slime–EPS by 90.26% and 99.25%, respectively. Approximately 92.35% of humic acid-like materials in tightly bound EPS were reduced by MMPs. Thus, coupling magnetic conditioning should be selected as pretreatment prior to HED.
01/01/2016 00:00:00
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7. Extra: chemical treatments

Back

Out of scope and incomplete, but added here as additional information on (conditioning) methods to dewater biomass.


7.1 Coagulation

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In water treatment, coagulation flocculation involves the addition of compounds that promote the clumping of fines into larger floc so that they can be more easily separated from the water. [\[link\]](https://en.wikipedia.org/wiki/Coagulation_(water_treatment)) **Highlights:** * The results indicate that the collagen dispersion was effective as a **coagulant** for removing turbidity caused by colloidal clay particles and as a sludge conditioner for **thickening and dewatering sludge** from a water treatment plant. [\[Art. #ARTNUM\]](#article-96038-2031184665)

7.1.1 Coagulation
Collagen dispersions for liquid-solid separations in water treatment and sludge dewatering
Abstract Studies were conducted to evaluate potential applications of collagen dispersions in liquid-solid separation processes for water treatment and sludge dewatering. The collagen dispersion was prepared from fibrillar type I bovine hide buffered with organic acid. The results indicate that the collagen dispersion was effective as a coagulant for removing turbidity caused by colloidal clay particles and as a sludge conditioner for thickening and dewatering sludge from a water treatment plant. Coagulation of kaolin suspensions using the collagen reduced the initial turbidity of the suspension by 92%. Additions of collagen to sludge from a water treatment plant improved the settling rate during gravity thickening by a factor of five and improved the specific cake resistance of the sludge during filtration by a factor of three. Research is continuing on the mechanisms and kinetics of collagen dispersions in coagulation and sludge dewatering.
08/01/1995 00:00:00
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7.2 Flocculation

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Flocculation, in the field of chemistry, is a process in which colloids come out of suspension in the form of floc or flake, either spontaneously or due to the addition of a clarifying agent. [\[link\]](https://en.wikipedia.org/wiki/Flocculation) **Highlights:** * The process of **pelleting flocculation**, a further development of classical flocculation technology, is defined as a formation of wet pellets directly in a liquid medium. \[...\] The present paper deals with the results originating from laboratory scale experiments with model **sludge**, kaolin suspension. \[...\] The layering process was conducted in the presence of different **cationic flocculants** and the resulting relationships with respect to their nature and to the applied energy level have been assessed. The achieved agglomerates exhibit an “onion like” structure with densities up to 1.42 g/cm 3 and **solid matter content up to 48% after gravity dewatering.**[ \[Art. #ARTNUM\]](#article-96284-1979966683) [ ](#article-96284-1979966683)

7.2.1 Flocculation
Pelleting flocculation—an alternative technique to optimise sludge conditioning
Abstract The process of pelleting flocculation, a further development of classical flocculation technology, is defined as a formation of wet pellets directly in a liquid medium. Apart from well described mechanisms of flocculation like perikinetic and orthokinetic flocculation, the mechanism responsible for the formation of dense agglomerates is the mechanical syneresis guaranteed by the appropriate reactor form. Upon the two established models in the literature: the series system and the parallel system, experiments were performed to simulate a layer-by-layer particle deposition on the so-called “mother seeds” conforming to the parallel system. The present paper deals with the results originating from laboratory scale experiments with model sludge, kaolin suspension. The layering process was conducted in the presence of different cationic flocculants and the resulting relationships with respect to their nature and to the applied energy level have been assessed. The achieved agglomerates exhibit an “onion like” structure with densities up to 1.42 g/cm 3 and solid matter content up to 48% after gravity dewatering. Thus generated sludge agglomerates reveal the optimisation potential for sludge treatment manifested by improved characteristics achieved during the conditioning.
06/01/2005 00:00:00
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7.3 Gel extraction

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Temperaturesentitive gels that absorb water. **Highlights:** * **Gel extraction** is evaluated as a novel technique for **dewatering fine coal slurries**. This technique uses **temperature-responsive gels** to absorb water from slurries at low temperatures; after separation of the swollen gel from the dewatered slurry, the gel is heated slightly above ambient temperature, which causes it to release the water it absorbed. The gel can then be recycled. \[...\] The gels effectively dewatered slurries to around **70 wt% solids.**[ \[Art. #ARTNUM\]](#article-96285-2154396994) * An applicable use of **thermosensitive porous gel** for **dewatering of organic slurry** was investigated. The gel was synthesized with N-isopropylacrylamide (NIPAm) as monomer and N-,N′-methylenebisacrylamide (MBAA) as cross-linker. \[...\] The **water content of the slurry decreased from 91 to 60%**, and the water-absorbing rate increased by increasing the concentration of cross-linker used to prepare the gel. The dewatered cake was easily removed from the plate-like gel surface. The repeated dewatering did not much influence the dewatering rate of the gel within 50 times of recycling.[ \[Art. #ARTNUM\]](#article-96285-2025901589)

7.3.1 Gel extraction
Dewartering of Organic Slurry Using Thermosensitive Porous Gel
An applicable use of thermosensitive porous gel for dewatering of organic slurry was investigated. The gel was synthesized with N-isopropylacrylamide (NIPAm) as monomer and N-,N′-methylenebisacrylamide (MBAA) as cross-linker. The porous gel was obtained by simple radical polymerization at higher temperature than the LCST (Lower Critical Solution Temperature) of the N-isopropylacrylamide polymer. At such a high temperature, phase separation occurs with the progress of polymerization, and a porous structure is formed. The porous gel swells and shrinks about 100 times faster than non-porous gel. The porous structure develops with an increasing concentration of the cross-linker.In this research, the plate-like porous gel with a support was prepared to improve the mechanical strength of the porous gel. A stainless steel net was used to support the porous gel. The effect of the support on the swelling properties of the gel was examined, and the dewatering of organic slurry by using such a plate-like porous gel was examined. The plate-like gel with the support swelled anisotropically. The gel with the support was strong enough to use repeatedly for dewatering the organic slurry. The water content of the slurry decreased from 91 to 60%, and the water-absorbing rate increased by increasing the concentration of cross-linker used to prepare the gel. The dewatered cake was easily removed from the plate-like gel surface. The repeated dewatering did not much influence the dewatering rate of the gel within 50 times of recycling.
01/01/2004 00:00:00
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7.3.2 Gel extraction
DEWATERING FINE COAL SLURRIES BY GEL EXTRACTION
ABSTRACT Gel extraction is evaluated as a novel technique for dewatering fine coal slurries. This technique uses temperature-responsive gels to absorb water from slurries at low temperatures; after separation of the swollen gel from the dewatered slurry, the gel is heated slightly above ambient temperature, which causes it to release the water it absorbed. The gel can then be recycled. The equilibrium and kinetic properties of poly(N-isopropylacrylamide) gel were evaluated for utility in this process. The gels effectively dewatered slurries to around 70 wt% solids; performance was not a strong function of particle size, though coarser slurries (−16 mesh) could be dewatered to greater extents than the finer slurries (325 = 400 mesh). The gels showed no sign of deterioration over a period of 2 months and 20 cycles.
01/01/1998 00:00:00
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7.4 Fenton's reagent

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Fenton's reagent is a solution of hydrogen peroxide (H2O2) with ferrous iron (typically iron(II) sulfate, FeSO4) as a catalyst that is used to oxidize contaminants or waste waters. Fenton's reagent can be used to destroy organic compounds such as trichloroethylene (TCE) and tetrachloroethylene (perchloroethylene, PCE). [\[link\]](https://en.wikipedia.org/wiki/Fenton%27s_reagent) **Highlights:** * Extensive efforts have been put into the disruption of EPS for **improving the dewaterability of excess sludge** and **Fenton's reagent treatment** has been demonstrated to be a very promising sludge conditioning method for EPS destruction. \[...\] This paper may pave a path to deeply understand the mechanisms of **dewatering improvements** of excess sludge by Fenton's conditioning. [\[Art. #ARTNUM\]](#article-95997-2949543634)

7.4.1 Fenton's reagent
Insight into the fenton-induced degradation process of extracellular polymeric substances (EPS) extracted from activated sludge
Abstract Although EPS in microbial aggregates are importance in successful implementation of biological wastewater treatment systems, they also exhibit detrimental role on certain circumstance, such as excess sludge dewatering. Extensive efforts have been put into the disruption of EPS for improving the dewaterability of excess sludge and Fenton's reagent treatment has been demonstrated to be a very promising sludge conditioning method for EPS destruction. However, the information regarding detailed degradation process of EPS during Fenton's reagent treatment is limited. In this study, EPS were extracted from activated sludge and treated with different concentrations of Fenton's reagent. The physicochemical characteristic changes of EPS under different treatment were investigated in terms of components, EEM, molecular weight (MW), UV-Vis and FTIR. The results showed that EPS were prone to be disintegrated, but hard to be fully mineralized. Humic substances in EPS were more resistant to Fenton's reagent than other components. Low MW components of EPS were preferentially degraded prior to the disruption of high MW components. Besides, the disintegration of EPS into lower MW ones was accompanied by the formation of higher MW compounds caused by the bridge interaction of Fe ions. The cleavage of protein's backbone in EPS was mainly through destruction of amide II (N–H and C–N) in –CO–NH–. Fenton's reagent treatment also led to a significant increase of oxygen-containing functional groups in EPS molecules. This paper may pave a path to deeply understand the mechanisms of dewatering improvements of excess sludge by Fenton's conditioning.
11/01/2019 00:00:00
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7.5 Polyelectrolyte

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Polyelectrolytes are polymers whose repeating units bear an electrolyte group. Polycations and polyanions are polyelectrolytes. These groups dissociate in aqueous solutions (water), making the polymers charged. Polyelectrolyte properties are thus similar to both electrolytes (salts) and polymers (high molecular weight compounds) and are sometimes called polysalts. Like salts, their solutions are electrically conductive. Like polymers, their solutions are often viscous.[\[link\]](https://en.wikipedia.org/wiki/Polyelectrolyte) **Highlights:** * The conditioning and dewatering behaviors of **chemical and waste activated sludges** from a tannery were studied. \[...\] Experiments were conducted on each sludge conditioned and dewatered separately, and on the **sludge mixed** at various ratios. Results indicate that the chemical sludge was relatively difficult to be dewatered, even in the presence of **polyelectrolyte**. When the **waste activated sludge was mixed with the chemical sludge** at ratios of 1 : 1 and 2 : 1, respectively, the **dewaterability of chemical sludge improved** remarkably while the relatively better dewaterability of the waste activated sludge deteriorated only to a limited extent. As the mixing ratios became 4 : 1 and 8 : 1, the dewaterability of the mixed sludge was equal to that of the waste activated sludge. The **optimal polyelectrolyte dosage** for the mixed sludge was equal to or less than that of the waste activated sludge.[ \[Art. #ARTNUM\]](#article-96007-2080709504) * This study compared the **dewatering properties of aerobic granular and activated sludge** from full-scale wastewater treatment plants, and determined how **polymer dose** and type affect granular sludge dewatering efficiency. At the same dose, granular sludge filtration cake had about 4% lower humidity than activated sludge cake. Aerobic stabilization improved only activated sludge dewatering.[ \[Art. #ARTNUM\]](#article-96007-2972124297)

7.5.1 Polyelectrolyte
CO-conditioning and dewatering of chemical sludge and waste activated sludge
Abstract The conditioning and dewatering behaviors of chemical and waste activated sludges from a tannery were studied. Capillary suction time (CST), specific resistance to filtration (SRF), and bound water content were used to evaluate the sludge dewatering behaviors. Zeta potentials were also measured. Experiments were conducted on each sludge conditioned and dewatered separately, and on the sludge mixed at various ratios. Results indicate that the chemical sludge was relatively difficult to be dewatered, even in the presence of polyelectrolyte. When the waste activated sludge was mixed with the chemical sludge at ratios of 1 : 1 and 2 : 1, respectively, the dewaterability of chemical sludge improved remarkably while the relatively better dewaterability of the waste activated sludge deteriorated only to a limited extent. As the mixing ratios became 4 : 1 and 8 : 1, the dewaterability of the mixed sludge was equal to that of the waste activated sludge. The optimal polyelectrolyte dosage for the mixed sludge was equal to or less than that of the waste activated sludge. It is proposed that the chemical sludges act as skeleton builders that reduce the compressibility of the mixed sludge whose dewaterability is enhanced. Bound water contents of sludge decreased at low polyelectrolyte dosage and were not significantly affected as polyelectrolyte dosage increased. Advantages and disadvantages of co-conditioning and dewatering chemical sludge and waste activated sludge were discussed.
02/01/2001 00:00:00
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7.5.2 Polyelectrolyte
Efficient dewatering of polymer-rich aerobic granular sludge with cationic polymer containing hydrocarbons
This study compared the dewatering properties of aerobic granular and activated sludge from full-scale wastewater treatment plants, and determined how polymer dose and type affect granular sludge dewatering efficiency. At the same dose, granular sludge filtration cake had about 4% lower humidity than activated sludge cake. Aerobic stabilization improved only activated sludge dewatering. The granular sludge reactor had over 1.5 times more extracellular polymeric substances (1.8 times more alginate) per reactor volume than the activated sludge reactor, but the high polymer content did not decrease granular sludge dewatering. Granular sludge dewatered best with FLOPAM EM 840MEB, due to its composition (n-alkanes, isoalkanes, cyclic/aromatic hydrocarbons). With this polymer, sludge cake moisture was lowest (84.7 ± 0.4%) at 1.6 g polymer/kg MLSS. With all tested polymers, the lowest dose (0.2 g/kg MLSS) ensured low cake humidities; this dose was far lower than typical doses for activated sludge dewatering. Upgrading from activated to granular sludge technology significantly facilitates excess sludge management.
09/03/2019 00:00:00
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7.6 Alum sludge

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An alum is a type of chemical compound, usually a hydrated double sulfate salt of aluminium with the general formula XAl(SO4)2·12H2O, where X is a monovalent cation such as potassium or ammonium. [\[link\]](https://en.wikipedia.org/wiki/Alum) **Highlights:** * **Alum sludge** acted as **chemical conditioner and physical conditioner** **improved the sewage sludge dewatering**. It indicated that the addition of alum sludge reduced the dosage of polyacrylamide (PAM) and **decreased the moisture content** of sewage sludge. The moisture content was **64%** when the blend ratio was 1 kg/kg (dry alum sludge/dry sewage sludge) with plate-and-frame filter press. \[...\] A mechanism hypothesis of adding alum sludge in sewage sludge for improving the sludge dewatering was proposed.[ \[Art. #ARTNUM\]](#article-96026-1441955743)

7.6.1 Alum sludge
Effect of adding alum sludge from water treatment plant on sewage sludge dewatering
Abstract Alum sludge from water treatment plant contained residual polyaluminum chloride (PACl) and large amount inorganic matters. Alum sludge acted as chemical conditioner and physical conditioner improved the sewage sludge dewatering. It indicated that the addition of alum sludge reduced the dosage of polyacrylamide (PAM) and decreased the moisture content of sewage sludge. The moisture content was 64% when the blend ratio was 1 kg/kg (dry alum sludge/dry sewage sludge) with plate-and-frame filter press. The 3D-excitation–emission matrix (3D-EEM) was used to analyze the sludge dewatering process. A mechanism hypothesis of adding alum sludge in sewage sludge for improving the sludge dewatering was proposed. Alum sludge implements the charge neutralization and adsorption bridging effect, provides friction and squeeze for crushing sludge particles even cell, and acts as skeleton builders in the sludge to improve the sludge dewatering.
03/01/2016 00:00:00
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7.7 Fly-ash

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Fly ash or flue ash, also known as pulverised fuel ash in the United Kingdom, is a coal combustion product that is composed of the particulates (fine particles of burned fuel) that are driven out of coal-fired boilers together with the flue gases. Depending upon the source and composition of the coal being burned, the components of fly ash vary considerably, but all fly ash includes substantial amounts of silicon dioxide (SiO2) (both amorphous and crystalline), aluminium oxide (Al2O3) and calcium oxide (CaO), the main mineral compounds in coal-bearing rock strata. [\[link\]](https://en.wikipedia.org/wiki/Fly_ash) **Highlights:** * The **effects of fly-ash on dewatering of sewage sludge** were studied according to sludge specific resistance (SSR), dehydrated speed, and moisture content of sludge cake as investigation indexes through single-factor experiments by contrasting to **cationic polyacrylamide (PAM).** \[...\] When the dosage of fly-ash was over 0.03 g/(ml sludge) adding with PAM, the dehydrated speed will be increased by three fourths. \[...\] Through the analyses of Zeta potential, scanning electron microscope (SEM) observation, combined with the dehydration experiments, it was thought that the mechanism of fly-ash on dewatering of sewage sludge was that their particles evenly dispersed in sludge floc skeleton structure and thus decreased the SSR and **improved the permeability of the sludge cake.** The disposal of dewatering sludge and recycling approaches after fly-ash condition were also discussed. They can be used as **landfill or as raw materials in building fields**.[ \[Art. #ARTNUM\]](#article-96030-2088735178)

7.7.1 Fly-ash
Mechanism and Application Prospects of Sewage Sludge Conditioning with Fly-Ash
The effects of fly-ash on dewatering of sewage sludge were studied according to sludge specific resistance (SSR), dehydrated speed, and moisture content of sludge cake as investigation indexes through single-factor experiments by contrasting to cationic polyacrylamide (PAM). The results showed that SSR kept decreasing with the rising of fly-ash dosage. When the dosage of fly-ash was 0.02 g/(ml sludge), SSR reduced by 65.2%. When the dosage of fly-ash was over 0.03 g/(ml sludge) adding with PAM, the dehydrated speed will be increased by three fourths. Through the analyses of Zeta potential, scanning electron microscope (SEM) observation, combined with the dehydration experiments, it was thought that the mechanism of fly-ash on dewatering of sewage sludge was that their particles evenly dispersed in sludge floc skeleton structure and thus decreased the SSR and improved the permeability of the sludge cake. The disposal of dewatering sludge and recycling approaches after fly-ash condition were also discussed. They can be used as landfill or as raw materials in building fields.
01/01/2014 00:00:00
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7.8 Dimethyl ether

0

Dimethyl ether (DME, also known as methoxymethane) is the organic compound with the formula CH3OCH3, simplified to C2H6O. [\[link\]](https://en.wikipedia.org/wiki/Dimethyl_ether) **Highlights:** * The suitability of using **dimethyl ether** (DME) in **dewatering coal** for the treatment of **sewage sludge** has been found empirically to be highly effective. We investigated the effectiveness of a method involving the use of DME for dewatering electroplating sludge and tried to clarify the mechanism and characteristics of the dewatering process.[ \[Art. #ARTNUM\]](#article-96043-2092689709)

7.8.1 Dimethyl ether
DEWATERING OF ELECTROPLATING SLUDGE USING DIMETHYL ETHER
The suitability of using dimethyl ether (DME) in dewatering coal for the treatment of sewage sludge has been found empirically to be highly effective. We investigated the effectiveness of a method involving the use of DME for dewatering electroplating sludge and tried to clarify the mechanism and characteristics of the dewatering process. Two zinc-containing sludge samples were examined and the effect of the volume of liquefied DME on the dewatering process was assessed. During the initial dewatering phase, the dewatering ratio is dependent only on the saturation degree of water in liquefied DME. In the later phase, it depends proportionally on the water concentration in the sludge and has a pattern that reduces the dewatering rate as dewatering is proceeded. Moreover, the dewatering pattern can be expressed using one dewatering rate constant, k.   The water contained in the sludge samples was analyzed using thermogravimetry/differential thermal analysis and the evaporation temperature range was determined. The water remaining in the samples after dewatering was found to be thermally stable and tightly bound. We further determined the amounts of total carbon and metal elements in the dewatered water and compared the concentrations to those specified in the Japan Water Pollution Quality Control Act. An important observation is that the dewatered water from the samples requires further processing before it can be discharged into the drainage system due to the presence of large amounts of Cu, Pb and Zn.
01/01/2010 00:00:00
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Final Results

Published 07/10/2020

After the midway results meeting, 11 dewatering technologies have been reviewed and deepened. The results are organised based on the concept and presented per dewatering technology comprising a description, findings, suppliers (if applicable), images, videos, useful links and a reference list. The technology requirements are measured and shown in the [requirements table](#requirements-table). By using the concept links below, you can quickly navigate to the concepts and their dewatering technologies descriptions.

Table of concepts:

  1. 1. Filtration
  2. 2. Force and/or temperature based approaches
  3. 3. Electrokinetics
  4. 4. Radiation
  5. 5. Combinations

Technology Radar
Requirements Table

1. Filtration

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Dewatering methods based on filtration.


1.1 Filter press

0

An industrial filter press is a tool used in separation processes, specifically to separate solids and liquids. The process uses the principle of pressure drive, as provided by a slurry pump. [\[link\]](https://en.wikipedia.org/wiki/Filter_press) **Note:** thermal treatments combined with filter press are included here. **Highlights:** * As part of an ongoing study to improve the **cassava starch** manufacturing process, a potential improvement to the dewatering stage was explored. \[...\] At all filtering conditions, the pressure filter provided improved dewatering efficiency. The filtration rate significantly increased from 162 to 226 g m -2 s -1 and starch loss, to the circulation, notably decreased from 15 to 0.15%. \[...\] The pressure filter not only improved dewatering efficiency but also minimized production cost due to a lower starch cake moisture, which requires **less energy consumption** for subsequent drying.[ \[Art. #ARTNUM\]](#article-96002-2032056753) **Combined with thermal treatment:** * A new sewage sludge semi-drying (dewatering) process is proposed and verified. It **combines thermal hydrolysis** and subsequent mechanical dewatering, with **less energy consumption** than traditional thermal drying. Sludge treated using this new process satisfies further disposal requirements (e.g., landfill or autothermal incineration). In the present study, a high-pressure test reactor was used to study the thermal hydrolysis of dewatered sludge. Thermally hydrolyzed sludge was subsequently dewatered by centrifugal sedimentation or by pressure filtration. [\[Art. #ARTNUM\]](#article-96002-2028845792) * **Thermal filter press** dewatering equipment composed of squeezing plate and a fixed heating plate was developed to improve the dewaterability of **pigment sludge** as supplying the heat from the fixed heating plate to the cake. \[...\] In this research, it was resulted that the squeezing process and long dewatering time were effective to improve the dewaterability of pigment sludge. So, this thermal filter press equipment was useful for dewatering the fine particle sludge like pigment. [\[Art. #ARTNUM\]](#article-96002-267445013) * Thermal dewatering describes the process whereby a heating plate and heat supply unit are incorporated into a filter press system to improve separation of water from sludge. The performance of our thermal dewatering system for both **wastewater and waterworks sludge** was measured \[...\] Dewatering velocity was improved by a factor of two, cake water content was lower, and specific cake resistance was improved. However, **energy consumption was higher.** Thermal dewatering systems may be economical and have practical application to improving dewaterability.[ \[Art. #ARTNUM\]](#article-96002-1965310669) * The thermal filter press dewatering (TFPD) technology to improve the dewaterability through increasing the inner vapor pressure, lowering the filtration viscosity and forming the porosity easily within cake as applying the heat at the sludge layer was developed in this study. \[...\] the dewatered cake water content was about 35 wt% and dewatering velocity was under the rainwater period, and the dewatered cake water content was about 50 wt% and dewatering velocity was in the case of sludge of water shortage season \[...\] On the base of the results of TFPD, energy consumpted to deal with DS(Dry Solid) of 1kg was estimated by **300 kJ.** \[...\] this technology was recognized that dewaterability was predominant because of the fast of dewatering velocity and production of low water content cake, and also this known as economical efficiency was excellent because of **low energy consumption** in comparison with dryer.[ \[Art. #ARTNUM\]](#article-96002-2991961033) * **Steam dewatering** of filter cakes is recognized as a competitive alternative to conventional air drying and thermally assisted mechanical dewatering (TAMD). \[...\] The first **mineral,** kaolin, was very difficult to dewater using conventional mechanical dewatering techniques, whereas the second one, ground calcium carbonate (GCC), represented only moderate resistance to filtration.[ \[Art. #ARTNUM\]](#article-96002-2032368528) **Other treatments:** * A new conditioning process made up of an acidic oxidative pre-conditioning step that is based on the **Fenton reagent** (essentially H 2 O 2 and FeCl 2 ) and followed by a corresponding inorganic post-conditioning step with **calcium hydrate** is presented. By means of this new conditioning process, even **undigested biological waste tratement sludges** are dewatered in membrane filter presses to a water loading of only 1.0-1.2 H 2 O/kg SDM O (suspended dry matter) with normal filtration/press times. [\[Art. #ARTNUM\]](#article-96002-2067100902) * The effects of **ozone treatment** on the dewaterability of **activated sludge wasted from a sewage** treatment plant were investigated in this study. Following ozone treatment, sludge was dewatered using a pressure filter. The sludge filterability evaluated by SRF deteriorated with ozone dosage at relatively low ozone doses. However, at ozone doses higher than 0.6gO3/gSS, the SRF of the ozone treated sludge became comparable with the value for the sludge without ozone treatment. \[...\] In terms of cake volume, more than 55 % reduction was obtained at 0.4gO3/gSS. These observations suggest that ozone treatment has potential to significantly enhance sludge dewaterability and to produce a more compact cake without severe deterioration of its filterability. [\[Art. #ARTNUM\]](#article-96002-2274104247) * The raw dam water associated with the prototype unit is clarified using a **polyelectrolyte/bentonite mixture**. The resultant sludge has a mean solids concentration of 23 g/l. The prototype tubular filter press has produced on average a cake with a solids concentration of 32% mass/mass and a filtrate with a suspended solids of 57 mg/l.[ ](#article-96253-2048552757)[\[Art. #ARTNUM\]](#article-96002-2048552757) * The addition of **wood chips** combined with cationic polyacrylamide (CPAM) and polymeric aluminium chlorides (PACl) to sewage sludge was investigated to enhance the dewatering in a **pilot-scale plate-and-frame filter press.** The results indicated that the **chemical coagulation** significantly affected the moisture content (MC) and specific resistance to filtration (SRF) of the sludge in bench-scale tests. The lowest MC and SRF were 87.93% and 0.31 × 1011 m kg−1, respectively, for CPAM and PACl dosages of 0.04% and 4%, respectively. However, when the wood chips were combined with chemical coagulation conditioning, minimal improvements were noted in the sludge dewatering ability compared to the coagulation conditioning alone. Moreover, the addition of wood chips was effective for the subsequent plate-and-frame filter press dewatering process. The wood chips acted as skeleton builders during this high-pressure dewatering (1.0 MPa). The lowest MC was 50.3% when the dosages of CPAM, PACl and wood chips were 0.05%, 4% and 100%, respectively. [\[Art. #ARTNUM\]](#article-96002-2147218625) * In this paper, **Na 2 SiO 3** as new conditioner were used to adjust the urban sewage-dewatered sludge (UDSS). \[....\] The results showed when Na 2 SiO 3 was used alone, it had no effect on improving the UDSS’s dewatering performance. However, under the effect of **FeCl 3** , Na 2 SiO 3 can improve the dewaterability of UDSS. [\[Art. #ARTNUM\]](#article-96002-2546716860) * The invention discloses a technology for improving the dewaterability of excess sludge. The technology includes the first step of low-temperature **plasma aeration**, the second step of **acidity regulation**, the third step of **fenton-like oxidation** and the fourth step of **plate-frame pressure filtration.** The low-temperature plasma technology is combined with fenton-like oxidation for treatment the excess sludge together, sludge **cell walls are effectively damaged**, and the dewaterability of the sludge is improved. The water content after sludge dewatering is lower than 60%, the salt content is low, the heat value is high, and the technology is suitable for sanitary landfill and incineration and also suitable for aerobic fermentation to prepare biological organic fertilizers.[ \[Art. #ARTNUM\]](#article-96002-2825805534) * Chinese patent

1.1.1 Filter press
[Improvement of municipal sewage sludge dewaterability by bioleaching: a pilot-scale study with sequence batch reaction model].
To observe the bioleaching effect on sewage sludge dewaterability,three consecutive batch bioleaching experiments were conducted through a bioleaching bio-reactor with 700 L of working volume.Subsequently,the bioleached sludge was dewatered by using chamber filter press.The results show that the 1st batch bioleaching process can be finished within 90 hours if the aeration amount was 1.2 m3/h with the 1∶15 mixing ratio of bioleached sludge to raw sludge.The pH of sludge declines from initial 6.11 to 2.33 while ORP increased from initial-134 mV to finial 507 mV.The specific resistance to filtration(SRF) of the tested sludge was decreased from original 1.00×1013m/kg to final 0.09×1013m/kg after bioleaching.For the subsequent two batch trials,the bioleaching process can be finished in 40 hours and 46 hours,respectively.Likewise,sludge SRF is also significantly decreased to 0.19×1013m/kg and 0.36×1013m/kg if the mixing ratio of bioleached sludge to fresh sludge is 1∶1 although the microbial nutrient substance dosage is reduced by 25% and 50% for 2nd and 3rd batch experiments,respectively.The harvested bioleached sludge from three batch trails is dewatered by chamber filter press with 0.3-0.4 MPa working pressure for 2 hours.It is found that the moisture of dewatered sludge cake can be reduced to 58%,and that the dewatered sludge cake is of khaki appearance and didn't emit any offensive odor.In addition,it is also observes that sludge organic matter only changed a bit from 52.9% to 48.0%,but 58% of sludge-borne Cu and 88% of sludge-borne Zn can be removed from sludge by bioleaching process.Therefore,dual goals for sludge-borne heavy metal removal and sludge dewatering of high efficiency can be achieved simultaneously through the approach mentioned above.Therefore,bioleaching technique is of great engineering application for the treatment of sewage sludge.
07/01/2011 00:00:00
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1.1.2 Filter press
A new conditioning process for the dewatering of wastewater treatment sludge
A new conditioning process made up of an acidic oxidative pre-conditioning step that is based on the Fenton reagent (essentially H 2 O 2 and FeCl 2 ) and followed by a corresponding inorganic post-conditioning step with calcium hydrate is presented. By means of this new conditioning process, even undigested biological waste tratement sludges are dewatered in membrane filter presses to a water loading of only 1.0-1.2 H 2 O/kg SDM O (suspended dry matter) with normal filtration/press times.
08/01/2000 00:00:00
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1.1.3 Filter press
A study for Beating Filter Press Dewatering Technology
The thermal filter press dewatering(TFPD) technology to improve the dewaterability through increasing the inner vapor pressure, lowering the filtration viscosity and forming the porosity easily within cake as applying the heat at the sludge layer was developed in this study. The hot water with temperature of and pressure of was supplied to the heating plate equipped between filter plates with plate size of and material of polypropylene. Sludge was dewaterd by supplying pressure of and then by squeezing pressure of . As a results of estimating the characteristics of thermal dewatering to consider the initial water content and organic content to be influenced by a period of water shortage and rainwater, the dewatered cake water content was about 35 wt% and dewatering velocity was under the rainwater period, and the dewatered cake water content was about 50 wt% and dewatering velocity was in the case of sludge of water shortage season. These results was superior to the mechanical dewatering performance with water content of 70wt% and dewatering velocity of . On the base of the results of TFPD, energy consumpted to deal with DS(Dry Solid) of 1kg was estimated by 300 kJ. It was analyzed that the energy consumption of TFPD was decreased about one third with comparison to the dryer system. Dewatering velocity of this technology was faster than the one of mechanical dewatering equipment and it was easier to product low water content cake. Therefore, this technology was recognized that dewaterability was predominant because of the fast of dewatering velocity and production of low water content cake, and also this known as economical efficiency was excellent because of low energy consumption in comparison with dryer.
01/01/2006 00:00:00
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1.1.4 Filter press
A study on the Thermal Filter Press for the Reduction of Pigment Sludge
Dewatering process to remove water from pigment sludge was important in the diverse aspects of the improvement of product quality, curtailment of the drying cost and the transportation. It was difficult to dewater pigment particles with the mechanical forces because the size was fine under . Thermal filter press dewatering equipment composed of squeezing plate and a fixed heating plate was developed to improve the dewaterability of pigment the sludge as supplying the heat from the fixed heating plate to the cake. Several tests that estimate the dewaterability for pigment sludge as with or without squeezing process and the difference of dewatering time was conducted with this equipment. Dewaterability of thermal dewatering under squeezing process was increased about 20% compared with non squeezing process. Under squeezing process, thermal dewatering tests changing dewatering time with 70 and 80 minute were conducted respectively. The water content of cake was more reduced at dewatering time of 80 minute compared with 70 minute, and dewatering velocity was also decreased, which caused the productivity of thermal filter press to drop. It was observed that clogging of filter cloth didn't almost occur because the liquid was discharged from cake layer easily. In this research, it was resulted that the squeezing process and long dewatering time were effective to improve the dewaterability of pigment sludge. So, this thermal filter press equipment was useful for dewatering the fine particle sludge like pigment.
01/01/2009 00:00:00
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1.1.5 Filter press
An Improved Dewatering Performance in Cassava Starch Process by a Pressure Filter
As part of an ongoing study to improve the cassava starch manufacturing process, a potential improvement to the dewatering stage was explored. Two types of starch dewatering were compared, a pressure filter and a conventional centrifuge. Performance with respect to the dewatering efficiency of the starch slurry, implied by the filtration rate and percentage of dry solids in circulation, was measured for a pressure filter and a conventional centrifuge. For the pressure filter, effect of different filter cloths, feed time and pressing time were evaluated. At all filtering conditions, the pressure filter provided improved dewatering efficiency. The filtration rate significantly increased from 162 to 226 g m -2 s -1 and starch loss, to the circulation, notably decreased from 15 to 0.15%. Improvement in processing-efficiency did not sacrifice starch quality. Granule morphology and functional properties, such as paste viscosity, water adsorption, and solubility characteristics remained unchanged. One notable exception was that chemical compounds and microorganisms appeared to he more readily absorbed to the granule surface. The pressure filter not only improved dewatering efficiency but also minimized production cost due to a lower starch cake moisture, which requires less energy consumption for subsequent drying.
12/01/1999 00:00:00
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1.1.6 Filter press
Citric acid assisted Fenton-like process for enhanced dewaterability of waste activated sludge with in-situ generation of hydrogen peroxide
Abstract Fenton's reagent has been widely used to enhance sludge dewaterability. However, drawbacks associated with hydrogen peroxide (H 2 O 2 ) in Fenton's reagents exist, since it is a hazardous chemical and shows carcinogenicity, explosivity, instability, and corrosivity. Moreover, initial acidification and subsequent neutralization are needed as optimal conditions for homogeneous Fenton conditioning and final filtrate discharge. In this study, a Fenton-like process for the enhanced dewaterability of waste activated sludge with in-situ generation of H 2 O 2 and without extra pH adjustment was firstly proposed, namely citric acid (CA)-assisted oxygen activation in an air/nano zero-valent iron (nZVI) system and chemical re-coagulation with polydiallyldimethylammonium chloride (PDMDAAC). Using the response surface methodology (RSM), the optimal doses of CA, nZVI, and PDMDAAC were determined to be 13, 33, and 9 mg g −1 dry solids (DS), respectively. This composite conditioner showed a good dewatering capability compared with the raw sludge, e.g. the capillary suction time decreased from 130.0 to 9.5 s. The enhanced sludge dewaterability was further confirmed by laboratory-scale diaphragm filter press dewatering tests, which produced a lower cake moisture content compared with the raw sludge, and the final pH of the filtrate was close to neutrality. The citric acid promoted the production of H 2 O 2 and Fe(II)/Fe(III) species, the degradation of protein in tightly-bound extracellular polymeric substances, and the decomposition of protein-N in the solid phase of sludge, resulting a greater conversion of bound water to free water. The results of electron spin resonance indicated that the hydroxyl radicals were mainly responsible for the decomposition of proteinaceous compounds. The subsequent chemical re-coagulation with PDMDAAC can make the zeta potential of sludge samples less negative, reduce the repulsive electrostatic interactions, and agglomerate the smaller particles into larger aggregates, thus enhancing sludge dewaterability.
09/01/2018 00:00:00
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1.1.7 Filter press
Coal Slurry Dewatering Filter Press Improvement Design
For the realization of underground water warehouse coal slurry efficient dehydration processing, this paper presents a kind of new structure design and the corresponding hydraulic control principle of the double working area continuous press filter,which can realize two filter working condition,in order to adapt to the coal slurry rapid separation, improve the efficiency of coal slurry dewatering.
01/01/2013 00:00:00
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1.1.8 Filter press
Effect of adding wood chips on sewage sludge dewatering in a pilot-scale plate-and-frame filter press process
The addition of wood chips combined with cationic polyacrylamide (CPAM) and polymeric aluminium chlorides (PACl) to sewage sludge was investigated to enhance the dewatering in a pilot-scale plate-and-frame filter press. The results indicated that the chemical coagulation significantly affected the moisture content (MC) and specific resistance to filtration (SRF) of the sludge in bench-scale tests. The lowest MC and SRF were 87.93% and 0.31 × 1011 m kg−1, respectively, for CPAM and PACl dosages of 0.04% and 4%, respectively. However, when the wood chips were combined with chemical coagulation conditioning, minimal improvements were noted in the sludge dewatering ability compared to the coagulation conditioning alone. Moreover, the addition of wood chips was effective for the subsequent plate-and-frame filter press dewatering process. The wood chips acted as skeleton builders during this high-pressure dewatering (1.0 MPa). The lowest MC was 50.3% when the dosages of CPAM, PACl and wood chips were 0.05%, 4% and 100%, respectively. Furthermore, a wood chip dosage of 100% increased the high heat value (HV) and low HV of the products by 20% and 150%, respectively, compared to the control. Several subsequent disposal options, such as landfilling, incineration and bio-composting, are proposed as a result of the low MC and high low HV of the products.
01/01/2014 00:00:00
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1.1.9 Filter press
Effect of cationic surfactants and lime joint action on the dewaterability of sewage sludge
This paper studied the effect of cationic surfactants(rosin-based trimethylammonium,didodecyldimethylammonium bromide) combined with lime on the dewaterability of sewage using some evaluation indexes,i.e.,specific resistance to filtration(SRF),capillary suction time and water removal efficiency.The results showed that both cationic surfactants improved the dewaterability of sewage sludge.SRF and CST decreased with increasing dosages of the cationic surfactants.The combination of cationic surfactants and calcium oxide produced better results,making the sewage sludge more dewaterable.When the dosage of calcium oxide was 15 g per 100 g dry solid and the dosage of cationic surfactants was 9 g per 100 g dry solid,SRF of raw sludge was respectivery decreased to 17.7% and 23.0%;CST of raw sludge reduced to 52.3 s and 70.5 s,and with the water removal efficiency decreased to 86.9% and 84.2%.The surfactant and CaO joint action had a significant impact on the sludge floc and extracellular polymeric substances as the dosage increased,and increased the content of the organic matter,protein and polysaccharide.The improvement in sludge dewaterability was further confirmed by the results from the filter press dewatering experiments in the laboratory.
01/01/2013 00:00:00
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1.1.10 Filter press
Enhancement of Sludge Dewaterability by Ozone Treatment
The effects of ozone treatment on the dewaterability of activated sludge wasted from a sewage treatment plant were investigated in this study. Following ozone treatment, sludge was dewatered using a pressure filter. The sludge filterability evaluated by SRF deteriorated with ozone dosage at relatively low ozone doses. However, at ozone doses higher than 0.6gO3/gSS, the SRF of the ozone treated sludge became comparable with the value for the sludge without ozone treatment. It is suggested that the oxidation of the viscous, high molecule organics attached at cell surface reduces the surface charge of sludge particle and promotes flocculation at relatively high ozone doses. Ozone treatment also cause the release of bound water trapped inside cells or floes, resulting in significant reduction of cake water content after dewatering. In terms of cake volume, more than 55 % reduction was obtained at 0.4gO3/gSS. These observations suggest that ozone treatment has potential to significantly enhance sludge dewaterability and to produce a more compact cake without severe deterioration of its filterability.
11/01/2001 00:00:00
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1.1.11 Filter press
Experimental Study on Thermal Hydrolysis and Dewatering Characteristics of Mechanically Dewatered Sewage Sludge
After mechanical dewatering, sewage sludge has a moisture content of around 80 wt% and further disposal is required. A new sewage sludge semi-drying (dewatering) process is proposed and verified. It combines thermal hydrolysis and subsequent mechanical dewatering, with less energy consumption than traditional thermal drying. Sludge treated using this new process satisfies further disposal requirements (e.g., landfill or autothermal incineration). In the present study, a high-pressure test reactor was used to study the thermal hydrolysis of dewatered sludge. Thermally hydrolyzed sludge was subsequently dewatered by centrifugal sedimentation or by pressure filtration. The amount of organic compounds returning to the water phase was also measured. According to the results from centrifugal settling tests, the optimal thermal hydrolysis treatment temperature was 180°C. The moisture content then dropped to 1.44 kg/kg dry solids (DS; 59 wt%) after dewatering under relative centrifugal force of 9,000 × g from 5.6...
11/01/2011 00:00:00
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1.1.12 Filter press
Hydrothermal and alkaline hydrothermal pretreatments plus anaerobic digestion of sewage sludge for dewatering and biogas production: Bench-scale research and pilot-scale verification
Abstract To test the feasibility and practicability of the process combing hydrothermal pretreatment for dewatering with biogas production for full utilization of sewage sludge, hydrothermal/alkaline hydrothermal pretreatments and in turn anaerobic digestion of the filtrates obtained after dewatering the pretreated sludge were performed at bench- and pilot-scales. The hydrothermal temperature fell within the range of 140 °C–220 °C and the pretreatment time varied from 30 min to 120 min. For the alkaline hydrothermal pretreatment the pH value of the sludge was adjusted to 9.0–11.0 by adding Ca(OH) 2 . The results showed that the dewaterability of the sewage sludge was improved with increasing pretreatment temperature but the impact of the pretreatment time was not significant. The addition of Ca(OH) 2 gave better performance on the subsequent mechanical dewatering of the pretreated sludge compared to pure hydrothermal pretreatment, and the higher the pH value was, the better the dewaterability of the pretreated sludge was. The conditions of 180 °C/30 min and 160 °C/60 min/pH = 10.0 (for hydrothermal and alkaline hydrothermal pretreatments, respectively) resulted in relatively good results in the theoretical energy balance, which were verified in the pilot-scale tests. Based on the data from the pilot tests, the alkaline hydrothermal process realized self-sufficiency in energy at the cost of a proper amount of CaO.
06/01/2017 00:00:00
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1.1.13 Filter press
Life cycle assessment of dewatering routes for algae derived biodiesel processes
Biodiesel derived from algae is considered as a sustainable fuel, but proper downstream processing is necessary to minimize the environmental footprint of this process. Algae is grown in dilute liquid cultures, and achieving the low water contents required for extraction represents one of the greatest challenges for the production of algae derived biodiesel. An analysis of the life cycle emissions associated with harvesting, dewatering, extraction, reaction, and product purification stages for algae biodiesel were performed. This “base case” found 10,500 kg of total emissions per t of biodiesel with 96 % of those attributed to the spray dryer used for dewatering. Alternative cases were evaluated for various sequences of mechanical and thermal dewatering techniques. The best case, consisted of a disk-stack centrifuge, followed by the chamber filter press, and a heat integrated dryer. This resulted in 875 kg emissions/t of biodiesel, a 91 % reduction from the base case. Significant reductions in life cycle emissions were achieved for all mechanical dewatering alternatives compared to the base case, but further improvements using these existing technologies were limited. Additional improvements will require the development of new techniques for water removal or wet extractions.
08/01/2013 00:00:00
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1.1.14 Filter press
Method for dewatering and drying a liquid/solid slurry and an apparatus for using the method
The invention discloses an improved method, and apparatus for utilizing the method, for dewatering and drying a liquid/solid slurry. Unlike the prior known method of consecutive material thickening, filtering, crushing and then subsequent drying achieved with an appropriate for each process apparatus, in the present invention all these processes are achieved with only one apparatus.The apparatus for the implementation of this method comprises consecutively connected filter press, feeding-compressing container with pressure feed chamber and an inbuilt heat exchanger and vacuum collector with a vacuum pump. The advantages of using this apparatus and method are its compactness, limited space required, low energy consumption, environmental cleanliness and the fact that the separated liquid phase can be used as a heat carrier for industrial and municipal needs. In addition, the disclosed process if fully automated.The summary time for the consecutive implementation of the prior known method, including thickening, filtering, crushing and drying is considerably decreased using the present invention.The present invention eliminates the transportation costs and facilitates, which are unavoidable in the utilized up to now method.Moreover, in the drying process only a fraction of the residual liquid is vaporized, which pushes out the remaining part without its evaporation. Further, there is extraction of salts dissolved in the liquid, since the liquid is not vaporized.
10/31/1988 00:00:00
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1.1.15 Filter press
Processing method for dewatered mulberry leaves with high water content
The invention discloses a processing method for dewatered mulberry leaves with a high water content. The processing method comprises the following steps: firstly, enzyme deactivation is carried out, namely, fresh mulberry leaves in 1-10 leaf positions are taken and cleaned, microwave heating of central positions is carried out for enzyme deactivation, and then steam is inputted to carry out surface enzyme deactivation; secondly, cooling and dewatering are carried out, namely, the mulberry leaves after enzyme deactivation are immersed in a sodium chloride solution with a temperature of 5-15 DEG C and with a mass fraction of 0.5-1wt%, stirring is carried out for 0.5-1min to cool the mulberry leaves after enzyme deactivation rapidly, the cooled mulberry leaves are placed in a board-frame-type filter press and subjected to extrusion dewatering, and dewatered mulberry leaves with a water content of 50-60wt% are obtained; thirdly, penetration and drying are carried out, namely, the above dewatered mulberry leaves are immersed in a penetrating fluid of a compounding water activity lowering agent and are subjected to penetration processing, and then the mulberry leaves are sent to a hot air drying device and subjected to hot air drying. Fresh mulberry leaves in 1-10 leaf positions are employed as a raw material, dewatering mulberry leaves with a water content of 20-25% are prepared, the mulberry leaves can be eaten directly without rewatering, have good palatability and have high nutritive values, the water activity is lowered to 0.55-0.60, and the shelf life of dewatered mulberry leaves is prolonged obviously.
02/24/2016 00:00:00
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1.1.16 Filter press
Steam Dewatering of Filter Cakes in a Vertical Filter Press
Steam dewatering of filter cakes is recognized as a competitive alternative to conventional air drying and thermally assisted mechanical dewatering (TAMD). The main benefit of cake dewatering with high-pressure steam is that mechanical and thermal dewatering can be efficiently performed in a single process step. The target of this study was to determine the potential of a steam-dewatering technique for two industrial mineral suspensions. The first mineral, kaolin, was very difficult to dewater using conventional mechanical dewatering techniques, whereas the second one, ground calcium carbonate (GCC), represented only moderate resistance to filtration. The secondary objective was to compare the filterability of the original kaolin slurry with the same slurry treated with a coagulant (aluminum sulphate, Al2(SO4)3 · 16H2O). Four different kinds of experiments were performed: tests without any kind of cake dewatering, tests with air drying, tests with steam drying, and tests with both coagulation and steam dr...
07/27/2013 00:00:00
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1.1.17 Filter press
Synergetic conditioning of sewage sludge via Fe2+/persulfate and skeleton builder: Effect on sludge characteristics and dewaterability
Abstract High water affinity of extracellular polymeric substances (EPS) and high compressibility of sewage sludge solids have negative impacts on sludge dewatering. In this study, a composite conditioner, Fe 2+ –activated sodium persulfate (denoted as Fe 2+ /SPS) combined with thermal–pretreated phosphogypsum (PG), was used to improve the sludge dewaterability. The mechanism of the composite conditioning of sewage sludge was elucidated: the proteins in tightly bound EPS were transferred into the filtrate and loosely bound EPS, and the polysaccharides in loosely and tightly bound EPS were transferred into the filtrate; the bound water was released and reduced from 2.60 g/g DS (dry solid) initially to 0.81 g/g DS; specific resistance to filtration and capillary suction time were reduced by 91.6% and 88.4%, respectively. Radical quenching experiment indicated that sulfate radical (SO 4 − ) is the dominant free radical and plays an important role in determining the oxidation–reduction potential during conditioning. Moreover, both the XRD and SEM results clearly showed that Fe 2+ /SPS combined with PG promoted the generation of column–shaped dihydrate gypsum in the conditioned sludge. Thus, the dihydrate gypsum crystals could act as skeleton builders, which create a more permeable and rigid lattice structure of the sludge cake. The improvement of sludge dewatering was confirmed by diaphragm filter press dewatering process, which yielded 45.7 wt% cake moisture content and 91.7% dewatering efficiency.
06/01/2015 00:00:00
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1.1.18 Filter press
Technology for improving dewaterability of excess sludge
The invention discloses a technology for improving the dewaterability of excess sludge. The technology includes the first step of low-temperature plasma aeration, the second step of acidity regulation, the third step of fenton-like oxidation and the fourth step of plate-frame pressure filtration. The low-temperature plasma technology is combined with fenton-like oxidation for treatment the excess sludge together, sludge cell walls are effectively damaged, and the dewaterability of the sludge is improved. The water content after sludge dewatering is lower than 60%, the salt content is low, the heat value is high, and the technology is suitable for sanitary landfill and incineration and also suitable for aerobic fermentation to prepare biological organic fertilizers.
05/31/2017 00:00:00
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1.1.19 Filter press
The dewatering of sludges using a tubular filter press
Abstract A tubular filter press process using fabric tubes has been developed to dewater the sludge resulting from the clarification of raw water. A prototype plant, designed to dewater the sludge resulting from the treatment of 30 Ml/day of surface water, has been constructed by a water authority. The slurry is fed under pressure into an array of porous tubes, the liquid in the slurry filters through the tube walls while the slurry solids are deposited as a thin layer on the internal walls of the tubes. The cake is dislodged periodically from the tube walls and transported hydraulically out of the tubes where it is drained and conveyed to a collection hopper. The raw dam water associated with the prototype unit is clarified using a polyelectrolyte/bentonite mixture. The resultant sludge has a mean solids concentration of 23 g/l. The prototype tubular filter press has produced on average a cake with a solids concentration of 32% mass/mass and a filtrate with a suspended solids of 57 mg/l. The process operates with minimum supervision and no chemical addition. The solids dewatering capacity for a feed solids concentration of 23 g/l and operating at a pressure of 400 kPa is 1.5 kg dry solids/ m2 h. The performance of the unit can be described using standard filtration theory modified for a circular filtration surface. The performance to date indicates that this process compares favourably with other commercially available sludge dewatering methods.
12/01/1987 00:00:00
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1.1.20 Filter press
The study of Na2SiO3 as conditioner used to deep dewater the urban sewage dewatered sludge by filter press
Abstract In this paper, Na 2 SiO 3 as new conditioner were used to adjust the urban sewage-dewatered sludge (UDSS). By observing the changes of the dehydrate rate of UDSS with Na 2 SiO 3 and without Na 2 SiO 3 , the dewatering effect of Na 2 SiO 3 was studied. The results showed when Na 2 SiO 3 was used alone, it had no effect on improving the UDSS’s dewatering performance. However, under the effect of FeCl 3 , Na 2 SiO 3 can improve the dewaterability of UDSS. Besides, in order to determine the optimal conditions of Na 2 SiO 3 and FeCl 3 used in UDSS dewatering, the influence factors in the process of dehydration were all systematically studied, including the dosage of FeCl 3 , molar ratio of Si/Fe, the sequence of adding conditioner. The compound use of FeCl 3 , Na 2 SiO 3 and fly ash was also investigated, which could further reduce the moisture content of the filter cakes to about 45%. At last, to analyze the role of Na 2 SiO 3 in adjusting the UDSS, the Zeta potential and inner structure of UDSS conditioned by Na 2 SiO 3 and FeCl 3 were both studied. The results indicated that the networks structure produced by PAM in the UDSS was destroyed and a new kind of new networks structure was generated by Na 2 SiO 3 , which could improve the dewaterability of UDSS.
03/01/2017 00:00:00
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1.1.21 Filter press
Thermal dewatering (TDW) to reduce the water content of sludge
Thermal dewatering describes the process whereby a heating plate and heat supply unit are incorporated into a filter press system to improve separation of water from sludge. The performance of our thermal dewatering system for both wastewater and waterworks sludge was measured and compared with mechanical dewatering in terms of water content, dewatering velocity, cake specific resistance, and energy consumption. Dewatering velocity was improved by a factor of two, cake water content was lower, and specific cake resistance was improved. However, energy consumption was higher. Thermal dewatering systems may be economical and have practical application to improving dewaterability.
03/01/2006 00:00:00
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1.1.22 Filter press
Alternative additives to enhance slurry dewatering

1. A method comprising:adding a wash fluid to an alumina trihydrate bearing slurry comprising alumina trihydrate and caustic-soluble aluminate liquor;adding to the alumina trihydrate bearing slurry or to the wash fluid a composition comprising at least one R-succinic compound having a structure selected from formula (I) or formula (II), a conjugate acid-base of the R-succinic compound having a structure selected from formula (I) or formula (II), and combinations thereof; wherein formula (I) is and formula (II) is andwherein R and R′ are independent, distinct, and represent alkyl, alkenyl, or aromatic hydrocarbon groups containing 1-30 carbon atoms. 2. The method of claim 1, wherein the R-succinic compound is selected from octadecenyl succinic acid, hexadecenyl succinic acid, dodecenyl succinic acid, or any combination thereof. 3. The method of claim 1 wherein the composition further comprises a base. 4. The method of claim 1, further comprising in order:preparing an aqueous slurry of pulverized bauxite ore and caustic solution;digesting, comprising extracting alumina from the bauxite ore as a caustic-soluble aluminate liquor;clarifying, comprising removing solid particles from the liquor;precipitating, comprising forming the alumina trihydrate bearing slurry from the liquor, andclassifying, comprising separating alumina trihydrate seeds from the liquor. 5. The method of claim 1, further comprising:removing liquor and water from the alumina trihydrate bearing slurry to give alumina trihydrate. 6. The method of claim 5, further comprising calcining the alumina trihydrate. 7. The method of claim 1, wherein the R-succinic compound forms in situ within the alumina trihydrate bearing slurry or the wash fluid by opening the ring of an R-succinic anhydride compound. 8. The method of claim 7 in which the R-succinic compound forms from an anhydride added to the alumina trihydrate bearing slurry or the wash fluid. 9. The method of claim 1, wherein the wash fluid comprises water. 10. The method of claim 1, wherein the wash fluid consists essentially of water. 11. The method of claim 1, wherein the composition is added to the slurry alongside the wash fluid, before the wash fluid, after the wash fluid, or combinations thereof. 12. The method of claim 1, wherein the composition is added to the wash fluid. 13. The method of claim 5, wherein the removing liquor and water from the alumina trihydrate bearing slurry comprises filtration. 14. The method of claim 5, wherein the wash fluid is added to the slurry before the removing, during the removing, after the removing, or combinations thereof. 15. The method of claim 5, wherein the removing liquor and water from the alumina trihydrate bearing slurry comprises gravity separation, pressure separation, vacuum separation, or combinations thereof.
02/26/2014 00:00:00
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1.1.23 Filter press
Dewatering process

1. A process of dewatering an aqueous sewage sludge suspension employing a flocculating system comprisingi.) treating the suspension with a flocculating amount of a first flocculant having a molecular weight of at least one million and a dewatering amount of a second flocculant, which second flocculant is in the form of particulates,ii.) thickening the treated suspension of step i.) by release of free water,iii.) mixing the thickened suspension, wherein the second flocculant particulates are distributed throughout the thickened suspension of step ii.), using mixing equipment, andiv.) subjecting the suspension to mechanical compression dewatering to form a cake, wherein the first flocculant brings about flocculation and assists thickening of the suspension and the second flocculant further dewaters the suspension,characterised in that the second flocculant is a water-soluble or water swellable polymer formed from 80 to 100% by weight methyl chloride quaternary ammonium salt of dimethyl amino ethyl (meth)acrylate and 0 to 20% by weight acrylamide of intrinsic viscosity between 3 and 10 dl/g that is mixed into the suspension in the form of a water-soluble or water swellable particulate polymer having a particle diameter of at least 50 microns, wherein the first and second flocculants are not counterionic and the first flocculant is cationic acrylamide polymer. 2. A process according to claim 1 in which the compression dewatering employs an apparatus selected from the group consisting of belt press, filter press, screw press and centrifuge. 3. A process according to claim 1 in which the first flocculant and second flocculant are added substantially simultaneously. 4. A process according to claim 1 in which the first flocculant and second flocculant are combined into a single composition. 5. A process according to claim 4 in which the single composition is a particulate polymer product in which the first flocculant comprises particles having a diameter below 10 microns. 6. A process according to claim 1 in which the second flocculant comprises polymeric particles having a coating applied to the surface. 7. A process according to claim 6 in which the coating is a silicone. 8. A process according to claim 6 in which the coating is a water-soluble wax. 9. A process according to claim 1 in which the second flocculant is introduced into the suspension in form of a slurry in a liquid. 10. A process according to claim 9 in which the liquid is polyethylene glycol. 11. A process according to claim 1, wherein the second flocculant is a polymer of intrinsic viscosity between 4 and 10 dl/g. 12. A process according to claim 1, wherein the second flocculant is a particulate polymer having a particle diameter between 100 and 800 microns. 13. A process according to claim 1, wherein thickened suspension in step ii.) is a semi solid sludge paste.
02/28/2005 00:00:00
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1.1.24 Filter press
Method for preparing fermentable sugar from wood-based biomass

1. A method for preparing fermentable sugar from lignocellulosic biomass for use in fermentation of industrial microorganisms, consisting of the steps of: 1) adding water to coarsely ground or powder lignocellulosic biomass having an average particle diameter of 0.1 mm to 50 mm or powdered lignocellulosic biomass to produce a first mixture, heating the mixture at 95 to 140° C. for 1 to 60 minutes, and then dewatering the mixture before the first mixture cools down to produce a first solid residue; 2) adding water to the solid residue obtained in step 1), and subjecting the mixture to autohydrolysis pretreatment at 170 to 210° C. for 1 to 30 minutes; 3) subjecting the autohydrolyzed material obtained in step 2) to solid-liquid separation to obtain a solid residue containing an amount of 5 to 30 wt % based on the total amount of the liquid part of the autohydrolyzed material produces in the pretreatment process; 4) subjecting the solid residue obtained in step 3) to enzymatic saccharification at a temperature of 45 to 55° C. using a cellulase complex enzyme; 5) repeating solid-liquid separation and extraction using the saccharified material obtained in step 4) to obtain a sugar solution; and 6) subjecting the sugar solution obtained in step 5) to filtration, concentration and then impurity removal. 2. The method of claim 1 , wherein the weight ratio of the coarsely ground or powder lignocellulosic biomass having an average particle diameter of 0.1 mm to 50 mm or powdered lignocellulosic biomass to water in step 1) is in a range of 1:4 to 1:20. 3. The method of claim 1 , wherein the solid-liquid separation in step 3) is carried out by centrifugation, suction filtration or pressure filtration. 4. The method of claim 1 , wherein the recovery of the sugar solution of step 5) is carried out by batch type or continuous centrifugation, filter press or screw press. 5. The method of claim 1 , wherein the filtration, concentration and impurity removal of the sugar solution in step 6) are carried out by a membrane separation technique using a reverse osmosis membrane. 6. The method of claim 1 , wherein the fermentable sugar obtained in step 6) contains glucose in an amount of at least 30%.
12/26/2013 00:00:00
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1.1.25 Filter press
Methods of enhancing fine particle dewatering

1. A process for dewatering a slurry of hydrophobic coal particulate material comprising:i) forming a layer of hydrophobes on the surface of said hydrophobic coal particulate material and initially increasing the hydrophobicity of said hydrophobic coal particulate material by adding hydrocarbon oil to said slurry, wherein the hydrophobicity of said coal particulate material is increased;ii) adding a nonionic surfactant of hydrophile-lipophile balance (HLB) number less than 15 dissolved in at least one organic solvent;iii) allowing said nonionic surfactant to adsorb on less hydrophobic parts of the surface of said hydrophobic coal particulate material to further increase hydrophobicity of said hydrophobic coal particulate material having increased hydrophobicity from the addition of said hydrocarbon oil; andiv) effecting separation of water from said slurry of hydrophobic coal particulate material by subjecting said slurry to a mechanical method of dewatering. 2. The process of claim 1, further comprising agitating said slurry. 3. The process of claim 1, wherein said particulate material comprises particles of less than 2 mm in size. 4. The process of claim 1, wherein said nonionic surfactant is selected from the group consisting of: fatty acids, fatty esters, phosphate esters, hydrophobic polymers, ethers, glycol derivatives, sarcosine derivatives, silicon-based surfactants and polymers, sorbitan derivatives, sucrose and glucose esters and derivatives, lanolin-based derivatives, glycerol esters, ethoylated fatty esters, ethoxylated amines and amides, ethoxylated linear alcohols, ethoxylated tryglycerides, ethoylated vegetable oils, and ethoxylated fatty acids. 5. The process of claim 1, wherein said nonionic surfactant is dissolved in an oil of vegetable origin. 6. The process of claim 1, wherein said organic solvent includes a solvent selected from the group consisting of: light hydrocarbon oils and short-chain alcohols. 7. The process of claim 6, wherein said light hydrocarbon oils are selected from diesel oil, kerosene, gasoline, petroleum distillate, turpentine, naphtanic oils, and oils of vegetable origins. 8. The process of claim 6, wherein said short-chain alcohols have carbon atom numbers less than eight. 9. The process of claim 1, wherein said mechanical method of dewatering is selected from the group consisting of: vacuum filtration, pressure filtration, centrifugal filtration, and centrifugation. 10. A process for dewatering a slurry of hydrophobic coal particulate material comprising:forming a layer of hydrophobes on the surface of said hydrophobic coal particulate material and initially increasing the hydrophobicity of said hydrophobic coal particulate material by adding hydrocarbon oil to said slurry, wherein said hydrophobic coal particulate material exhibits a contact angle and the contact angle of said hydrophobic coal particulate material is below 45°;dissolving a nonionic surfactant of hydrophile-lipophile balance (HLB) number less than 15 in at least one organic solvent;adding said dissolved nonionic surfactant and said at least one organic solvent to said slurry; andallowing said nonionic surfactant to adsorb on less hydrophobic parts of the surface of said hydrophobic coal particulate material, to further increase the hydrophobicity of said material having increased hydrophobicity from the addition of said hydrocarbon oil, wherein said contact angle of said hydrophobic coal particulate material is above 45°; andeffecting separation of water from said slurry of hydrophobic coal particulate material by subjecting said slurry to a mechanical method of dewatering. 11. The process according to claim 10, further comprising agitating said slurry. 12. The process of claim 10, wherein said organic solvent includes a solvent selected from the group consisting of: light hydrocarbon oils and short-chain alcohols. 13. The process of claim 12, wherein said light hydrocarbon oils are selected from diesel oil, kerosene, gasoline, petroleum distillate, turpentine, naphtanic oils, and oils of vegetable origins. 14. The process of claim 12, wherein said short-chain alcohols have carbon atom numbers less than eight. 15. The process of claim 10, wherein said coal particulate material comprises particles of less than 2 mm in size. 16. A process for dewatering a slurry of superficially oxidized coal particles, comprising:i) initially regenerating the hydrophobic surface of said oxidized coal particles,ii) forming a layer of hydrophobes on the surface of said hydrophobic coal particulate material and increasing the hydrophobicity of said coal particles by adding hydrocarbon oil to said slurry,ii) adding a non-ionic surfactant of hydrophile-lipophile balance (HLB) number less than 15 dissolved in at least on organic solvent;iii) allowing said non-ionic surfactant to adsorb on less hydrophobic parts of the surface of said coal particles, to further increase the hydrophobicity of said coal particles having increased hydrophobicity from the addition of said hydrocarbon oil; andiv) effecting separation of water from said slurry of hydrophobic particulate material by subjecting said slurry to a mechanical method of dewatering. 17. The process of claim 16, wherein said superficially oxidized coal particles are wet ground in a ball mill to regenerate the hydrophobic surface.
08/03/2007 00:00:00
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1.2 Thermal compression

0

The use of temperature and pressure to filter sludge. **Highlights:** * In the present work, sewage sludge is dewatered by the thermal compression, which shows unique separation advantages of various materials, and the effects of applied temperature and pressure on the dewatering performance are investigated. The filtrate SCOD reveals that higher temperature benefits the **disruption of sludge flocs**, resulting in the release of organic content. According to the accumulative filtrate volume, higher temperature and pressure facilitate the dewatering process, obtaining sludge cake with lower moisture content. [\[Art. #ARTNUM\]](#article-96263-2148107480) * In this paper, the use of thermal compression to improve the sludge dewatering is investigated. The dewatering efficiency is affected by the applied temperature, pressure and the sludge mass. The bound water of the sludge is further reduced by thermal compression, improving the dewatering performance. The **solid content of the cake** obtained after 10 min mechanical compression and 60 min thermal compression at 120 oC and **4 MPa is 85.2%**.[ \[Art. #ARTNUM\]](#article-96263-2018117044) * Thermal compression was applied on the dewatering of sewage sludge with **coal as a filter aid**. Experiments with 0.25-1 mm coal particles (0.2 kg coal/kg dry sludge solid) obtained cakes of solid content over 49%. \[...\] The results showed that a total weight loss of 65.1% occurred from 25 °C to 800 °C, including two major weight loss stages corresponding to loss of moisture and volatile materials respectively.[ \[Art. #ARTNUM\]](#article-96263-2022103331)

1.2.1 Thermal compression
Dewatering of Sewage Sludge Using Thermal Compression
Mechanical compression is a traditional process for the dewatering of sewage sludge. However, the moisture content of the cake is still high, unfavorable for the sludge management. In this paper, the use of thermal compression to improve the sludge dewatering is investigated. The dewatering efficiency is affected by the applied temperature, pressure and the sludge mass. The bound water of the sludge is further reduced by thermal compression, improving the dewatering performance. The solid content of the cake obtained after 10 min mechanical compression and 60 min thermal compression at 120 oC and 4 MPa is 85.2%.
08/01/2012 00:00:00
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1.2.2 Thermal compression
Dewatering of Sewage Sludge with Coal as a Conditioner Using Thermal Compression
Thermal compression is effective for solid-liquid separation of various materials. In this paper, thermal compression was applied on the dewatering of sewage sludge with coal as a filter aid. Experiments with 0.25-1 mm coal particles (0.2 kg coal/kg dry sludge solid) obtained cakes of solid content over 49%. Higher dosage of coal generated cakes with lower moisture content. The combustion behavior of the sludge cake was studied using TG/DTG analysis. The results showed that a total weight loss of 65.1% occurred from 25 °C to 800 °C, including two major weight loss stages corresponding to loss of moisture and volatile materials respectively.
02/01/2013 00:00:00
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1.2.3 Thermal compression
Dewatering Performance of Sewage Sludge during the Thermal Compression Process
Sewage sludge proves to be difficult to dewater due to its composition and biological nature, and it is unsuitable for disposal with high moisture content. In the present work, sewage sludge is dewatered by the thermal compression, which shows unique separation advantages of various materials, and the effects of applied temperature and pressure on the dewatering performance are investigated. The filtrate SCOD reveals that higher temperature benefits the disruption of sludge flocs, resulting in the release of organic content. According to the accumulative filtrate volume, higher temperature and pressure facilitate the dewatering process, obtaining sludge cake with lower moisture content.
01/01/2014 00:00:00
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1.3 Hydraulic compression

0

A hydraulic compressor is any type of air compressor that is powered by hydraulics on a vehicle or machine. Hydraulic compressors convert hydraulic power into mechanical power, and then mechanical power to pneumatic power. [\[link\]](https://en.wikipedia.org/wiki/Hydraulic_compressor) **Highlights:** * In this paper, the mechanical press filtration (MPF) dewatering was performed under **ultrahigh pressure** in order to improve the dewatering performance of municipal sludge. \[...\] The results indicate that moisture content of sludge cake decreases gradually with the increase of compressed pressure and dewatering time as well as the decrease of weight of sludge, and the moisture content of municipal sludge can be reduced to as low as 30% with MPF dewatering. [\[Art. #ARTNUM\]](#article-96029-2955927510) * By virtue of the sludge pressure filtration device of the sewage treatment plant, water is forcedly extruded out of the sludge by using a hydraulic compression manner, so that the sludge can be dewatered; due to arrangement of devices such as the rotation shaft and a differential mechanism, the sludge can be **centrifugally** dewatered as required, so that the dewatering efficiency can be improved[ \[Art. #ARTNUM\]](#article-96029-2849370130) * Chinese patent * [Slidedeck](https://www.auri.org/wp-content/uploads/2012/09/Dewatering-of-Wet-Biomass-8-2012.pdf) of Auri (Agricultural Utilizaiton Research Institute) about 'HydroPress' tested with wet sugar beet tailings and pulp.  **Combined with thermal treatment:** * Thermally assisted mechanical dewatering (TAMD) is a new process for energy-efficient liquid/solids separation which enhances conventional-device efficiency. The main idea of this process is to supply a flow of heat in mechanical dewatering processes to favour the reduction of the liquid content. This is not a new idea but the proposed combination, especially the chosen operating conditions ( T P T piston  = 80 °C), the dry solid content of the press cake can reach 66%, compared to 36% at ambient temperature. \[...\]  the experimental set-up consists of a **compression cell** inserted in a **CARVER^®^ hydraulic press** \[...\] The cell consists of a compressive piston, a hollowed cylindrical vessel and a filter medium. [\[Art. #ARTNUM\]](#article-96029-2017184243) * To develop a technology that can efficiently convert dewatered sewage sludge cake into solid fuel, we experimentally investigated the effects of the **hydrothermal treatment** on dewaterability and carbon distributions. Dewatered sewage sludge cake with a water content of about 80 wt% could not be dewatered by increasing the pressure of a mechanical press. However, after hydrothermal treatment, the sewage sludge cake could be dewatered with a mechanical press. \[...\] On the basis of the above results, we proposed a novel solid fuel production system composed of the following processes: hydrothermal treatment, mechanical press treatment, concentration, and drying.[ \[Art. #ARTNUM\]](#article-96029-2005202300) **Other treatments:** * Based on the traditional processes, **sludge dewatered** by usual methods was further dewatered by **hydraulic compression** and the filtrate released was treated by anaerobic fermentation. The difficulties in sludge dewatering were associated with the existence of sludge flocs or colloidal materials. A suitable **CaO dosage** of 125 mg/g dry sludge (DS) could further decrease the moisture content of sludge from 82.4 to 50.9 %. [\[Art. #ARTNUM\]](#article-96029-2026853025)

1.3.1 Hydraulic compression
Application of a thermally assisted mechanical dewatering process to biomass.
Abstract Thermally assisted mechanical dewatering (TAMD) is a new process for energy-efficient liquid/solids separation which enhances conventional-device efficiency. The main idea of this process is to supply a flow of heat in mechanical dewatering processes to favour the reduction of the liquid content. This is not a new idea but the proposed combination, especially the chosen operating conditions ( T P T piston  = 80 °C), the dry solid content of the press cake can reach 66%, compared to 36% at ambient temperature. A significant regression model, describing changes on final dry solids content with respect to independent variables, was established with determination coefficient, R 2 , greater than 88%. With an energy consumption of less than 150 kWh/m 3 , the use of the TAMD process before a thermal drying process leads to an energy saving of at least 30% on the overall separation chain.
01/01/2011 00:00:00
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1.3.2 Hydraulic compression
Hydrothermal Treatment of Dewatered Sewage Sludge Cake for Solid Fuel Production
To develop a technology that can efficiently convert dewatered sewage sludge cake into solid fuel, we experimentally investigated the effects of the hydrothermal treatment on dewaterability and carbon distributions. Dewatered sewage sludge cake with a water content of about 80 wt% could not be dewatered by increasing the pressure of a mechanical press. However, after hydrothermal treatment, the sewage sludge cake could be dewatered with a mechanical press. Moisture content was negatively correlated with treatment temperature at temperatures below 473K but stayed about the same at temperatures above 473K in the range studied. Carbon contents in the residual solid after treatment with a mechanical press were negatively correlated with the reaction temperature of the hydrothermal treatment owing to the solubilization of part of the volatile carbons in the dewatered sewage sludge cake. On the basis of the above results, we proposed a novel solid fuel production system composed of the following processes: hydrothermal treatment, mechanical press treatment, concentration, and drying. The optimum operating temperature of hydrothermal treatment was 473K in the range studied, and at this temperature, we estimated that the energy input to obtain dry sewage sludge using the proposed system would be about two-thirds that of a conventional drying process.
01/01/2009 00:00:00
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1.3.3 Hydraulic compression
Integrated treatment of municipal sewage sludge by deep dewatering and anaerobic fermentation for biohydrogen production.
The increasing sludge generated in wastewater treatment plants poses a threat to the environment. Based on the traditional processes, sludge dewatered by usual methods was further dewatered by hydraulic compression and the filtrate released was treated by anaerobic fermentation. The difficulties in sludge dewatering were associated with the existence of sludge flocs or colloidal materials. A suitable CaO dosage of 125 mg/g dry sludge (DS) could further decrease the moisture content of sludge from 82.4 to 50.9 %. The filtrate from the dewatering procedure was a potential substrate for biohydrogen production. Adding zero-valent iron (ZVI) into the anaerobic system improved the biohydrogen yield by 20 %, and the COD removal rate was lifted by 10 % as well. Meanwhile, the sludge morphology and microbial community were altered. The novel method could greatly reduce the sludge volume and successfully treated filtrate along with the conversion of organics into biohydrogen.
02/01/2015 00:00:00
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1.3.4 Hydraulic compression
Meso-mechanism of mechanical dewatering of municipal sludge based on low-field nuclear magnetic resonance
Abstract Both huge volume and high moisture content of municipal sludge have brought great troubles and attracted extensive concerns in the world. In this paper, the mechanical press filtration (MPF) dewatering was performed under ultrahigh pressure in order to improve the dewatering performance of municipal sludge. Low-Field Nuclear Magnetic Resonance (NMR) technique was used to study the effect of MPF parameters on dewatering performance. Based on the pore characteristics of municipal sludge, a capillary bundle model was developed to explore the mesoscopic mechanisms of MPF dewatering. The results indicate that moisture content of sludge cake decreases gradually with the increase of compressed pressure and dewatering time as well as the decrease of weight of sludge, and the moisture content of municipal sludge can be reduced to as low as 30% with MPF dewatering. According to the peak and envelope area of relaxation time curve in NMR, it can be found that the size of pores decreases and the percentage of small pores increases during the dewatering process. Therefore, the capillary water cannot be removed by MPF method because the capillary pressure in very small pores increases evidently. Furthermore, the compaction degree of the outmost layer is generally higher than that of the middle layer, and the difference of moisture content between the middle and outmost layers of cake is 25%–28.4%. The present work may be helpful to understand the MPF dewatering mechanism and shed light on the new dewatering techniques of municipal sludge.
10/01/2019 00:00:00
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1.3.5 Hydraulic compression
Prediction of Oil Yield from Oil Palm Mesocarp Using Thermally Assisted Mechanical Dewatering (TAMD)
Thermally assisted mechanical dewatering (TAMD) is a new technology for the separation of solid/liquid. When applied to “nature-wet” biomass, the TAMD process significantly enhances the separation yield. In the present study, TAMD was used to extract the crude palm oil (CPO) from mesocarp. The CPO yield of 70.77 wt% was achieved at optimum parameters of 73.0 °C, 6.7 bar and 60 min of extraction time. This CPO yield was comparable with previous works on the enzymatic extraction and hot compressed water extraction (HCWE) with CPO yield of 71.0 and 70.50 wt% respectively. Apart from that, this value was higher for about 13.80% compared to commercial CPO extracted using screw press which obtained the oil yield of 61.0 wt%. Based on the literatures, the highest CPO yield was obtained from supercritical CO2 extraction at 77.0 wt% whereas the lowest CPO yield was extracted using subcritical R134a which gave 66.0 wt% of oil yield. Nevertheless, the operational conditions of supercritical CO2 were 300 bar and 80 °C which were higher than that of TAMD. In conclusion, TAMD extraction has a potential to be an alternative method to extract CPO by producing higher oil yield.
01/01/2020 00:00:00
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1.3.6 Hydraulic compression
Sludge pressure filtration device of sewage treatment plant
The utility model discloses a sludge pressure filtration device of a sewage treatment plant. The sludge pressure filtration device of the sewage treatment plant mainly consists of a rotation shaft, head plates, a filtration membrane and a pressure filtration cartridge, wherein the head plates are arranged on the rotation shaft in a sleeving manner; two ends of the pressure filtration cartridge are fixed on the head plates on two sides; a feeding opening is formed in one side of the pressure filtration cartridge; the filtration membrane is arranged in the pressure filtration cartridge; a through hole is formed in the area (under the feeding opening) of the filtration membrane; four hydraulic cylinders are axially arranged outside the pressure filtration cartridge; two ends of each hydraulic cylinder are fixed on the head plates on two sides; a sludge outlet is formed in one side (symmetric to the feeding opening) of the pressure filtration cartridge; and a water outlet is also formed in the pressure filtration cartridge. By virtue of the sludge pressure filtration device of the sewage treatment plant, water is forcedly extruded out of the sludge by using a hydraulic compression manner, so that the sludge can be dewatered; due to arrangement of devices such as the rotation shaft and a differential mechanism, the sludge can be centrifugally dewatered as required, so that the dewatering efficiency can be improved; by arranging a chemical agent adding valve, chemical agents for decomposing harmful substances in the sludge can be added when the sludge is dewatered, so that the secondary pollution generated after the sludge is discharged can be avoided.
10/15/2014 00:00:00
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1.4 Belt filter press

1

The belt filter (sometimes called a belt press filter, or belt filter press) is an industrial machine, used for solid/liquid separation processes, particularly the dewatering of sludges in the chemical industry, mining and water treatment. [\[link\]](https://en.wikipedia.org/wiki/Belt_filter) **Highlights:** * The productive process of **dewatering chemical sludge** with belt filter press was applied and tested for the need of 300 kt/a ethylene plant in JiHua Company. The optimum belts velocity, belts intensive pressures, inlet sludge, inlet flocculent and outlet sludge quantities were determined.[ \[Art. #ARTNUM\]](#article-96045-2376420144) * **Gravity belt thickening** is commonly used for dewatering activated sludge. However, only a few results concerning this process, and the mathematical description of the drainage of residual sludges, have been published. Laboratory drainage experiments were carried out on several **activated sludges** to compare different published modelling approaches. [\[Art. #ARTNUM\]](#article-96045-1985843659) * A belt filter press was chosen following laboratory work as the most **cost efficient equipment for dewatering the sludge**. A **mobile** belt filter press was brought to the sludge lagoon site and was used during the dewatering operation.[ \[Art. #ARTNUM\]](#article-96045-2340823079) * **Kraft pulp-mill waste activated-sludge (WAS)** was anaerobically digested at pilot-scale under various organic loading conditions to assess the effects of digestion on subsequent sludge solid/liquid separation in a belt filter press and the quality of the resulting filtrate. \[...\] The dewaterability of WAS and DS improved in mixtures with primary sludge (PS). DS dewatering performance improved with increasing feed solids concentration. [\[Art. #ARTNUM\]](#article-96045-1996715594) * **V-Fold™, a redesigned belt filter press**, on the other hand, offers continuous dewatering regardless of slurry flow rate or composition, and with minimal operator intervention[ \[Art. #ARTNUM\]](#article-96045-1975327892) **Patents:** * In the removal of the first portion of the capillary liquid, at least one first compression device continuously compresses the stream of the drained **ligno-cellulosic feedstock** to a first control pressure, while conveying the stream of the drained ligno- cellulosic feedstock in a flow direction of a belt filter press.[ \[Art. #ARTNUM\]](#article-96045-EP3054052A1) * Patent Beta Renewables * A method for producing lignin fuel, silica/sodium oxide, cellulose, and cellulose derivatives from **plant biomass** \[...\] withdrawing a solid material stream from the first counter-current extractor and passing the solid material stream through a belt-press filter, dewatering the solid material to between **70% and 80% total solids** [\[Art. #ARTNUM\]](#article-96045-US5735916) * Patent COLUSA BIOMASS ENERGY * A filter-pressing dewatering process and the belt filter press, it sprays the slurry on the mesh belt, it dewaters by gravity and adsorption, then it twines the filter mesh belts on two filter-pressing dewatering rollers. \[...\] The invention uses single row roller drive, **energy consumption is low**, dehydration is uniform, effect is good and quality slurry is high.[ \[Art. #ARTNUM\]](#article-96045-2923825739) * Chinese patent * Power source of the present invention only is 18KW, electric current<30A * A press filter comprises a gravity filtering stage followed by a first pressing stage, wherein partly dewatered slurry is pressed between converging sections of two filter belts and a second pressing stage where these belts pass round staggered rollers[ \[Art. #ARTNUM\]](#article-96045-2781030505) * Patent Komline-Sanderson Engineering Corp (see suppliers) * An improved process for the low-cost disposal of noxious sewage sludge in a safe way without polluting the environment. In the process, **sewage sludge** having a solids content of about **0.5 to 20 wt.%** is concentrated by pressing in a belt filter press, optionally followed by pressing in a high intensity press. \[...\] The dewatered sewage sludge is heated, flash evaporated and/or centrifuged, and mixed with a supplemental fuel e.g., liquid hydrocarbonaceous and/or solid carbonaceous fuel to produce a **pumpable fuel slurry** having a total **solids content** in the range of about **50 to 70 wt.%** and comprising about 10 to 40 wt.% dewatered sewage sludge and having a higher heating value in the range of about 5,000 to 14,000 BTU/Lb.[ \[Art. #ARTNUM\]](#article-96045-EP0607644A1) * Patent Texaco Development Corporation **Combined with treatments:** * Included are flexibility through use of the three methods, a soil-slurry cutoff wall around the plant site perimeter and another slurry cutoff wall around the sludge monofill, and belt filter presses that **dewater the sludge** using **polymer as a coagulant aid**. [\[Art. #ARTNUM\]](#article-96045-1498470584) * The setup included a plow simulator kit for drainage simulation and a mechanical dewatering unit, namely, the **Crown Press™**, which simulates full-scale belt filter press dewatering. The effects of **enzyme product additions prior to polymer conditioning** of biosolids samples were investigated.[ \[Art. #ARTNUM\]](#article-96045-2051695748) * By **enzymatic hydrolsis** it is possible to modify the hydrophilic, water-retaining organic compounds of the sludge in order to reduce its water content. **Enzymes improve mechanical dewatering** in common belt-type filter presses or decanters in combination with flocculation by means of special **flocculating aids**. [\[Art. #ARTNUM\]](#article-96045-2804630631) **Patents with treatments:** * A **twin belt filter press** system has an **amendment such as sawdust**, fed to a sludge or slurry being dewatered after the sludge/slurry has been initially dewatered in a gravity drain section to form a cake on a first porous belt. [ \[Art. #ARTNUM\]](#article-96045-US4961862) * Patent Baker Hughes * An improved method for dewatering thin slurries of **very fine clay or clay-like material** to yield high solids content filter cake, for example, **40% solids** and greater, by the use of **flocculating agent** combinations involving polyethylene oxide-type flocculating agents and polyacarylamide-type flocculating agents. \[...\] dewatering the slurry by means of a mechanical dewatering apparatus and feeding the thickened slurry to a belt press filter[ \[Art. #ARTNUM\]](#article-96045-337104709) * Patent Envirotech Corp

1.4.1 Belt filter press
A belt filter press for carbide slag slurry dehydration
The utility model discloses a belt filter press for carbide slag slurry dehydration, including first deflector roll, second deflector roll, squeeze roll, first screen and second screen, first screen is including being used for with the carbide slag slurry transport extremely first screen with horizontal movement portion between the second screen, the top of horizontal movement portion is provided with the feeder hopper, the below is provided with a water filtering groove, the discharge gate of feeder hopper and the transport tube body coupling of vertical setting, the transport tube is internal to be provided with the filter sieve that a slope set up, and the filter sieve lower extreme extends to the barrel along its length direction and outer and be connected with first strainer tub, the aperture of the sieve mesh of filter sieve is 3cm. The utility model discloses a squeeze roll was walked around in the laminating first screen and second screen are to carrying the carbide slag of going into to carry out the dehydration of filter -pressing formula, and it is efficient dewater, through the filter sieve in to carbide slag slurry the great granule of particle diameter filter in order to avoid a filter belt and the 2nd filter belt to push the damage, be favorable to lengthening its life.
08/24/2016 00:00:00
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1.4.2 Belt filter press
An economic, sustainability, and energetic model of biodiesel production from microalgae.
Abstract A new process evaluation methodology of microalgae biodiesel has been developed. Based on four evaluation criteria, i.e. the net energy ratio (NER), biodiesel production costs, greenhouse gases (GHG) emission rate and water footprint, the model compares various technologies for each step of the process, from cultivation to oil upgrading. An innovative pathway (hybrid raceway/PBR cultivation system, belt filter press for dewatering, wet lipid extraction, oil hydrotreating and anaerobic digestion of residues) shows good results in comparison to a reference pathway (doubled NER, lower GHG emission rate and water footprint). The production costs are still unfavourable (between 1.94 and 3.35 €/L of biodiesel). The most influential parameters have been targeted through a global sensitivity analysis and classified: (i) lipid productivity, (ii) the cultivation step, and (iii) the downstream processes. The use of low-carbon energy sources is required to achieve significant reductions of the biodiesel GHG emission rate compared to petroleum diesel.
05/01/2012 00:00:00
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1.4.3 Belt filter press
Anaerobic treatment of kraft pulp-mill waste activated-sludge: Sludge dewaterability and filtrate quality
Abstract Kraft pulp-mill waste activated-sludge (WAS) was anaerobically digested at pilot-scale under various organic loading conditions to assess the effects of digestion on subsequent sludge solid/liquid separation in a belt filter press and the quality of the resulting filtrate. Anaerobic digestion resulted in deteriorated dewaterability of WAS, as indicated by lower cake solids, lower solids capture, increased chemical usage and unstable or lower capacity of the belt filter press with digested sludge (DS) than with WAS. The dewaterability of WAS and DS improved in mixtures with primary sludge (PS). DS dewatering performance improved with increasing feed solids concentration. Dewatering of DS and WAS produced filtrates of similar quality in terms of total solids. The concentrations of soluble organic matter (COD S , BOD 7 , VA) in filtrates of DS were lower than of WAS. In the mill where experiments were conducted the DS plus PS dewatering filtrate would contain 13–47% of the soluble nitrogen and up to 10% of the soluble phosphorus of the composite wastewater, indicating that DS filtrate is a potential source of nutrients for the treatment of phosphorus- and nitrogen-deficient kraft pulp-mill wastewater.
01/01/1992 00:00:00
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1.4.4 Belt filter press
Coal slurry dewatering arrangement
A coal slurry dewatering arrangement includes a filter belt press with a filter belt having first and second sides, the first side being water-impermeable and the second side having pores and being water-permeable, wherein the water-permeable side includes a layer of water-absorbent material.
10/08/2012 00:00:00
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1.4.5 Belt filter press
Dewatering of fine coal refuse: Final report, August 1985--December 1987
A major area of concern in modern coal preparation plants is the filtration and dewatering of fine coal/refuse. Fine coal in slurry form must be dewatered to minimize handling and transportation problems and to maximize its calorific value. The main emphasis of the present work is on the study of enhanced dewatering of fine coal and refuse using vacuum, air pressure and vacuum plus pressure expression (using a belt filter press) techniques. The objective of the study is to seek improved methods of dewatering through a better understanding of filtration and post-filtration processes. Coal refuse obtained from a southwestern Pennsylvania mine and coal samples obtained from several different sources were used in this study. The effects of a number of surface active agents and flocculants on filtration and dewatering of the coal and refuse were studied. Porosity and single phase permeability data were obtained along with the micrographic analysis of the filter cakes. In the case of pressure expression by belt filter press, the effects of belt speed and applied hydraulic pressure were studied. 34 refs., 85 figs., 9 tabs.
01/01/1988 00:00:00
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1.4.6 Belt filter press
Dewatering process and apparatus
Apparatus for enhancing dewatering of sludge on a filter belt by the use of conical plows that elevate and mix the sludge. The angles of the plows with the horizontal may be progressively increased, and thereby increase elevation and mixing of the sludge as it moves downstream on the belt toward discharge position.
07/20/1989 00:00:00
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1.4.7 Belt filter press
Disposal technology for recovering slurry by utilizing gravity in paper making industry
The invention belongs to the technical field of paper making sewage disposal, and particularly relates to a disposal technology for recovering slurry by utilizing gravity in the paper making industry.The technology includes the following steps that a, a flocculant is added into paper making sewage of a mixer to conduct thorough mixing and generate flocculating constituents; b, the flocculating constituents are fed into an oblique concentration segment of a belt filter press through a feeding device, and under the action of the gravity, dissociative water is drained out quickly along with themovement of a surface net to form slurry dregs; c, the slurry dregs dewatered by the oblique concentration segment are fed into a gravity dewatering segment of the belt filter press for further dewatering and then fed into an S-shaped squeezing segment to be dewatered again; d, finally, the slurry dregs are scrapped off by scrapers to obtain the slurry used for reproduction. Disposal is conductedon the paper making sewage through the belt filter press, the slurry in the belt filter press is reused, the sewage emission amount is reduced, the resources are saved, and the cost is decreased.
06/29/2018 00:00:00
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1.4.8 Belt filter press
Enhanced sludge conditioning by enzyme pre-treatment: comparison of laboratory and pilot scale dewatering results
The effect of enzyme pre-treatment on dewaterability of anaerobically digested sludge was investigated at both laboratory and pilot scale. Our results revealed a significant increase in cake solid content (27% cake solids compared to 18% without enzyme pre-treatment), using an enzyme dose of only 20 mg/L. In order to assess practical application, enzyme pre-treatment was applied at the Wilmington, Delaware (US) wastewater treatment plant, using a pilot-scale centrifuge. However, the efficiency reached in laboratory scale could not be obtained in pilot scale, where the final cake solids content did not exceed 20%. Centrifuge and belt filter press (simulated by Crown Press™) dewatering were compared in terms of the process efficiencies in the absence and presence of enzyme pre-treatment. Possible factors that might cause the differences were tested by experimental and statistical comparisons. Results indicated that the higher shear applied in centrifugation is responsible for the lack of improved cake solids. The network strength of sludge determined by rheological measurements revealed that enzymatic treatment weakens the gel structure of the sludge floc through the hydrolysis of extracellular polymeric substances; this allows improved dewatering by filtration processes, but leads to floc deterioration when subjected to high shear during centrifugation.
09/01/2006 00:00:00
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1.4.9 Belt filter press
Enhancing the dewaterability of anaerobically digested sludge using fibrous materials recovered from primary sludge: demonstration from a field study
Sludge dewatering is an important process for determining the operation cost of sludge disposal. Hence, improving the dewaterability of anaerobically digested sludge containing high water content is of paramount significance. For this challenge, we developed a novel process in which fibrous materials initially collected from a primary sedimentation tank, namely recovered fibers, were used as an auxiliary agent to improve the dewaterability of anaerobically digested sludge. The objective of this study was to investigate the feasibility of using the developed process to improve sludge dewaterability. Three fibrous materials individually recovered from the respective primary sedimentation tanks in different wastewater treatment plants (WWTPs) were used to investigate sludge dewaterability, organic C compositions, and calorific values. The recovered fibers showed comparable compositions irrespective of the WWTP. Six different WWTP sludge samples after anaerobic digestion were continuously supplied to three different dewatering devices, i.e., screw press, centrifuge, and belt press machines, with or without the supply of recovered fibers. Irrespective of the type of a dewatering device, the supply of recovered fibers mixed with the tested sludge samples at a feed ratio of 0.18–0.20 g-fibers/g-sludge (dry weight) reduced the amount of polymer flocculant by 13–50%, thereby displaying the superiority of the addition of recovered fibers. Furthermore, at fiber feed ratios of 0.20 g-fibers/g-sludge and 0.40 g-fibers/g-sludge when the rates of sludge supply and polymer flocculant were kept constant, the corresponding water contents in the dewatered sludge cakes decreased to about 74–76% and 69–72%, respectively. The consistent results regardless of the dewatering device or sludge sample showed the significance of the addition of recovered fibers for improvement in sludge dewaterability.
04/24/2019 00:00:00
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1.4.10 Belt filter press
Enzymatic treatment effects on dewaterability of anaerobically digested biosolids-II: laboratory characterizations of drainability and filterability
Abstract This paper provides an analysis of different measurements and derived parameters that may be used to characterize drainability and filterability dynamics. To better simulate the phenomena of gravity drainage and expression dewatering, specific devices and procedures were used in bench-scale conditioning and dewatering experiments. The setup included a plow simulator kit for drainage simulation and a mechanical dewatering unit, namely, the Crown Press™, which simulates full-scale belt filter press dewatering. The effects of enzyme product additions prior to polymer conditioning of biosolids samples were investigated. The results showed that enzyme additions enhanced the drainability of the biosolids samples and this positively affected filterability of the samples in the press unit. According to these results, enzyme product addition for biosolids samples with polymer conditioning seems a promising new method of enhancing the performance of mechanical dewatering units in the future.
06/01/2005 00:00:00
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1.4.11 Belt filter press
Flocculating agent combinations for mineral slime filtration systems
An improved method for dewatering thin slurries of very fine clay or clay-like material to yield high solids content filter cake, for example, 40% solids and greater, by the use of flocculating agent combinations involving polyethylene oxide-type flocculating agents and polyacarylamide-type flocculating agents. The method generally involves admixing the combination of flocculating agents with the slurry, dewatering the slurry by means of a mechanical dewatering apparatus and feeding the thickened slurry to a belt press filter.
06/05/1990 00:00:00
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1.4.12 Belt filter press
Flocculating, concentrating and filter-pressing integrated belt-type press filter
The utility model discloses a flocculating, concentrating and filter pressing integrated belt pressure filter, which belongs to the solid-liquid separation technology field in order to solve the problems in prior belt pressure filter that that structure is complex, the dewatering efficiency is low. A flocculating region, a concentrating and dewatering region, a gravity dewatering region, a transition dewatering region and a pressure dewatering region are sequentially arranged on a pressure filter main frame from the slurry entering end; the concentrating and dewatering region is connected on the flocculating region of the machine frame; the gravity dewatering region is connected at the rear part of the concentrating and dewatering region; the pressure dewatering region is connected at the rear part of the gravity dewatering region; a pressure filtering belt which is integrated with an upper filtering belt, a lower filtering belt and a gravity dewatering filtering belt into one body is arranged on a pressure roller group of the pressure dewatering region; and a filtering belt tensioner and a pressure deviation rectifier which is connected with the pressure roller group are respectively arranged on the pressure filter main frame, and a mud-receiving hopper which is connected with an end roller of the pressure roller group is arranged at the side of the pressure filter main frame. The pressure filter has the advantages that: the structure is novel, the filter is applied to the mud dewatering in the wastewater and sewage treatment, as well as to the solid-liquid separation in the fields of petroleum, chemical engineering, metallurgy, paper making, mining industry, food industry and the like.
07/03/2008 00:00:00
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1.4.13 Belt filter press
Gravity drainage of activated sludge: from laboratory experiments to industrial process
Gravity belt thickening is commonly used for dewatering activated sludge. However, only a few results concerning this process, and the mathematical description of the drainage of residual sludges, have been published. Laboratory drainage experiments were carried out on several activated sludges to compare different published modelling approaches. Data showed a linear relationship between the infinite mass of the cake (M C ) and the total mass of the dry solids in the initial sludge sample (DS): M C = α 1 x DS + α 2 so, an empirical equation was modified to predict the evolution of the cake dry solids content-over time: DS C (t) = DS/(α 1 × DS + α 2 ) + (c 1 x exp(c 2 x DS) × t + 1 M 0 - (α 1 × DS + α 2 ) -1 Two sets of empirical coefficients were derived according to the range of the initial dry solids content of the sludge (C b 2%). These coefficients were not significantly influenced by the origin of the activated sludge and thus can be considered as constants. Simulation results using the chosen model accord will with experiments carried out on an industrial gravity belt thickener working under field conditions.
05/01/2004 00:00:00
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1.4.14 Belt filter press
Improved Sludge Dewatering by Enzymatic Treatment
Nowadays West Germany produces 50 million cubic metres of liquid sludge per year. This tendency is still on the increase, whereas traditional means of utilisation, such as in agriculture, show a sharp decline. For this reason, about 60 - 70 % of the sludge has to be deposited at waste tips with a limited capacity. Therefore it is highly desirable to reduce the sludge volume as much as possible. By enzymatic hydrolsis it is possible to modify the hydrophilic, water-retaining organic compounds of the sludge in order to reduce its water content. Enzymes improve mechanical dewatering in common belt-type filter presses or decanters in combination with flocculation by means of special flocculating aids.
07/01/1993 00:00:00
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1.4.15 Belt filter press
Innovative belt filter press takes the hard work out of sludge dewatering
Abstract Small to medium sized operations often produce wastewater with highly variable quality, which presents a number of problems to conventional filtration systems. V-Fold™, a redesigned belt filter press, on the other hand, offers continuous dewatering regardless of slurry flow rate or compostion, and with minimal operator intervention. Paul Day, founder of Dayco Pty Ltd, Australia, explains.
10/01/2002 00:00:00
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1.4.16 Belt filter press
Lime Sludge Lagoon Dewatering Using a Mobile Belt Filter Press
A major company was faced with the removal of 2100 cubic yards of lime sludge stored in three lagoons. Because the sludge contained relatively high concentrations of tin and nickel, it was classified as a hazardous waste and required disposal in a hazardous waste landfill located over 400 miles from the manufacturing facility. Because of the high cost due to transportation of the solidified sludge, the contractor investigated several dewatering techniques. A belt filter press was chosen following laboratory work as the most cost efficient equipment for dewatering the sludge. A mobile belt filter press was brought to the sludge lagoon site and was used during the dewatering operation. As an end result, approximately 2100 cubic yards of the sludge was dewatered and transported to the hazardous waste landfill at a cost of under 200,000. 00. A detailed case history of the dewatering operation is presented. (Edited author abstract. )
01/01/1985 00:00:00
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1.4.17 Belt filter press
Movable slurry dewatering and curing system
The utility model provides a movable slurry dewatering and curing system. The device comprises a movable bearing platform, a two-stage muddy water separation part, a precipitation part and a sludge concentration and filter pressing part, wherein the two-stage muddy water separation part, the precipitation part and the sludge concentration and filter pressing part are sequentially adjacent left andright and are connected and distributed on the movable bearing platform, and a transition water tank is further connected between the two-stage muddy water separation part and the precipitation part;the two-stage muddy water separation part comprises a first-stage coarse filtering vibration sieve and a second-stage fine filtering vibration sieve which are adjacently arranged up and down, and thefirst-stage coarse filtering vibration sieve and the second-stage fine filtering vibration sieve are obliquely arranged on the movable bearing platform through a mounting frame; and the sludge concentration and filter pressing part comprises a sludge concentration tank and a sludge belt filter press. By the adoption of the system, the layout structure is compact, the occupied space is small, gooddehydration and solidification treatment of original desilting sewage can be achieved, energy consumption can be effectively reduced, and the slurry dehydration efficiency is guaranteed.
06/18/2019 00:00:00
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1.4.18 Belt filter press
Moving belt press filter
A press filter comprises a gravity filtering stage 17 followed by a first pressing stage, wherein partly dewatered slurry is pressed between converging sections of two filter belts 18, 19, and a second pressing stage where these belts pass round staggered rollers 29 - 29. In the first pressing stage the belts pass between upper and lower alternately spaced supports 42, 51 mounted on respective frames 43, 52. The angle of convergence between the frames, and hence to degree of pressing applied by the belts is adjustable by a pair of rams 60 which move respective lower wedges 59 relative to upper wedges 58. This mechanism is duplicated on the two edges of the lower belt, and the two rams are geared together to ensure they act in unison. Supports 42, 51 impose a degree of kneading on the slurry between the belts. The edge regions are urged together by rollers 49 and lower supports bent up along edge regions (Fig. 3) or by rollers (149) spaced longitudinally (Figs. 7, 8). Fig. 1 shows a separate gravity filtering belt 11, but in Fig. 9 the upper press belt 19 performs this function also.
07/14/1994 00:00:00
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1.4.19 Belt filter press
Pressure filtration technology and band type filter press for realizing said process
A filter-pressing dewatering process and the belt filter press, it sprays the slurry on the mesh belt, it dewaters by gravity and adsorption, then it twines the filter mesh belts on two filter-pressing dewatering rollers consecutively to make the filter mesh belts be wave, then it filter-pressing dewaters under the function of twist movement force. Power drives the active directing rollers; the completed slurry is delivered between the active and the driven directing rollers. The invention resolves the technical problems of complex equipment structure, high costs and poor dehydration results in background technology. The invention uses single row roller drive, energy consumption is low, dehydration is uniform, effect is good and quality slurry is high.
01/27/2006 00:00:00
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1.4.20 Belt filter press
PROCESS FOR PRODUCING FUEL FROM SEWAGE SLUDGE
An improved process for the low-cost disposal of noxious sewage sludge in a safe way without polluting the environment. In the process, sewage sludge having a solids content of about 0.5 to 20 wt.% is concentrated by pressing in a belt filter press, optionally followed by pressing in a high intensity press. It was unexpectedly found that the morphology of the resulting dewatered sewage sludge is changed by such mechanical treatment so that slurries with higher concentrations of solids are achieved. The dewatered sewage sludge is heated, flash evaporated and/or centrifuged, and mixed with a supplemental fuel e.g., liquid hydrocarbonaceous and/or solid carbonaceous fuel to produce a pumpable fuel slurry having a total solids content in the range of about 50 to 70 wt.% and comprising about 10 to 40 wt.% dewatered sewage sludge and having a higher heating value in the range of about 5,000 to 14,000 BTU/Lb. The fuel slurry may be reacted by partial oxidation in a conventional gasifier to produce synthesis gas and/or fuel gas. The thermal energy in hot by-product steam and flue gas streams are used to heat the dewatered sewage sludge. In one embodiment, the pumpable slurry of dewatered sewage sludge and supplemental fuel is burned by complete combustion in a furnace or incinerator for the production of steam.
09/06/1994 00:00:00
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1.4.21 Belt filter press
Production method of cassava starch
The invention discloses a production method of cassava starch. The production method comprises the steps of: washing and peeling cassava, crushing, dewatering and drying. The production method is characterized by also comprising a first-stage filter-pressing rough screening step, or a second-stage filter-pressing rough screening step, a third-stage filter-pressing rough screening step, first-stage to third-stage filter-pressing rough screening steps and first-stage and third-stage filter-pressing rough screening steps. According to the filter-pressing rough screening steps, the crushed cassava is subjected to filter-pressing by adopting a belt-type filter press, and starch slurry and manioc waste are separated out. The belt-type filter press is an efficient energy-saving belt type filter press. According to the production method, electric energy and water volume are consumed in the existing production method of the cassava starch, great links are reconstructed, the power of a motor is fully utilized, the water consumption is only 1/3 that of a vertical screening machine, and the filter-pressing slurry discharging speed of the efficient energy-saving belt-type filter press is 3 times that of the vertical screening machine. A large quantity of electric energy and water are saved, the environment is effectively protected, and the productivity of the cassava starch is increased.
10/09/2013 00:00:00
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1.4.22 Belt filter press
Productive application of dewatering chemical sludge with belt filter press
The productive process of dewatering chemical sludge with belt filter press was applied and tested for the need of 300 kt/a ethylene plant in JiHua Company.The optimum belts velocity ,belts intensive pressures,inlet sludge, inlet flocculent and outlet sludge quantities were determined .Technological and economic indexes to be guaranteed were finished with higher economic and environmental profit.A great number of running fees can be saved by applying DYQ2000-XB model belt filter press instead of WL(F)-600Ⅱ model centrifuge in the condition of same outlet sludge quantities.
01/01/2005 00:00:00
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1.4.23 Belt filter press
RefCoM: Proof-of-concept experiment: Final report (1978-1985)
This report presents the results of a Proof-of-Concept-Experiment on a biological process for the production of a substitute natural gas from municipal solid waste. Construction of a facility with a nominal capacity of 100 ton/day of as received refuse was completed in May, 1978. After the initial mechanical shake-down, plant operations was initiated in November, 1978. Numerous mechanical and operational difficulties were encountered in the refuse processing subsystem. A variety of problems were identified and solution developed. However, all of these problems were not resolved sufficiently to obtain a sustained gas production until the fall of 1981. The installation of a completely new refuse separation system in 1982 permitted the continuous feeding of the anaerobic fermenters. The performance of the fermenters when continuous feeding was initiated was equal to or better than predicted from the laboratory data. Methane yields as high as 5.5 SCF/lb volatile solids fed were obtained at the thermophilic fermentation temperature. Fermenter operational problems were identified and corrected. Dewatering of the fermenter slurry was most effective with a belt-press filter. 16 refs., 3 figs., 12 tabs.
07/01/1986 00:00:00
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1.4.24 Belt filter press
River sediment dehydration system
The utility model discloses a river sediment dehydration system. The sludge dewatering system comprises a screening machine communicated with the output end of a dredging device, a sludge concentration pool communicated with the sludge output end of the screening machine, and a belt filter press for dewatering sludge, wherein a thickening tank group is arranged between the sludge concentration tank and the belt filter press, and comprises more than one sludge thickening tank which is sequentially communicated through a connecting pipeline. According to the utility model, the dense tank group is additionally arranged between the sludge concentration tank and the belt filter press, so that the volume of the sludge concentration tank can be properly reduced, the construction investment of the sludge concentration tank is reduced, and meanwhile, slurry in the sludge concentration tank can run relatively stably through the lifting pump without manual secondary dredging.
09/20/2019 00:00:00
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1.4.25 Belt filter press
Sludge Disposal Dallas Style
Dallas, Tex. has discovered that sludge disposal can coexist with environmental concerns. Dallas Water Utilities treats some 200 million gpd, sending the effluent from one of the two treatment facilities to the other, the Southside Plant, where the sludge was disposed of on-site by liquid injjection into dedicated land disposal fields. In 1985 a Sludge Master Plan was adopted that recommended anaerobic digestion of all sludges, mechanical dewatering and sludge disposal by three methods: 1) on-site dedicated land disposal, 2) on-site sludge-only monofill, and 3) composting. Under this Plan, a new facility, the first phase of a $90 million project had been constructed. The design team retained by the city confirmed that these methods would be the most cost effective. Their design includes several innovations that have attracted observers to the plant. Included are flexibility through use of the three methods, a soil-slurry cutoff wall around the plant site perimeter and another slurry cutoff wall around the sludge monofill, and belt filter presses that dewater the sludge using polymer as a coagulant aid. Mixing the sludge with soil in a pug mill prior to disposal, pre-testing dewatering equipment prior to award, contracting operation of the monofill to private company are also included.
01/01/1990 00:00:00
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1.4.26 Belt filter press
Superstructure optimization and energetic feasibility analysis of process of repetitive extraction of hydrocarbons from Botryococcus braunii – a species of microalgae
Microalgae are potential resources for producing renewable fuel; however, the process of fuel production from microalgae is itself highly energy consuming and not commercially feasible, yet. Repetitive non-destructive extraction, also called repetitive milking, is a novel method for production of hydrocarbons from Botryococcus braunii – a species of microalgae. In this study, superstructure optimization technique is used to analyse the energetic feasibility of the repetitive milking process and to find the suitable technology options for each stage involved. The repetitive milking process is found to be energetically positive with an average net energy ratio of two for the optimum route. Open pond, cylindrical sieve rotator filter and nanofiltration were found to be the optimum technologies for growth and hydrocarbon production, dewatering and solvent recovery stages, respectively. Belt filter press and vibratory screen filter for dewatering and distillation for solvent recovery are also found to be energetically feasible technologies.
02/01/2017 00:00:00
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1.4.27 Belt filter press
Alternative additives to enhance slurry dewatering

1. A method comprising:adding a wash fluid to an alumina trihydrate bearing slurry comprising alumina trihydrate and caustic-soluble aluminate liquor;adding to the alumina trihydrate bearing slurry or to the wash fluid a composition comprising at least one R-succinic compound having a structure selected from formula (I) or formula (II), a conjugate acid-base of the R-succinic compound having a structure selected from formula (I) or formula (II), and combinations thereof; wherein formula (I) is and formula (II) is andwherein R and R′ are independent, distinct, and represent alkyl, alkenyl, or aromatic hydrocarbon groups containing 1-30 carbon atoms. 2. The method of claim 1, wherein the R-succinic compound is selected from octadecenyl succinic acid, hexadecenyl succinic acid, dodecenyl succinic acid, or any combination thereof. 3. The method of claim 1 wherein the composition further comprises a base. 4. The method of claim 1, further comprising in order:preparing an aqueous slurry of pulverized bauxite ore and caustic solution;digesting, comprising extracting alumina from the bauxite ore as a caustic-soluble aluminate liquor;clarifying, comprising removing solid particles from the liquor;precipitating, comprising forming the alumina trihydrate bearing slurry from the liquor, andclassifying, comprising separating alumina trihydrate seeds from the liquor. 5. The method of claim 1, further comprising:removing liquor and water from the alumina trihydrate bearing slurry to give alumina trihydrate. 6. The method of claim 5, further comprising calcining the alumina trihydrate. 7. The method of claim 1, wherein the R-succinic compound forms in situ within the alumina trihydrate bearing slurry or the wash fluid by opening the ring of an R-succinic anhydride compound. 8. The method of claim 7 in which the R-succinic compound forms from an anhydride added to the alumina trihydrate bearing slurry or the wash fluid. 9. The method of claim 1, wherein the wash fluid comprises water. 10. The method of claim 1, wherein the wash fluid consists essentially of water. 11. The method of claim 1, wherein the composition is added to the slurry alongside the wash fluid, before the wash fluid, after the wash fluid, or combinations thereof. 12. The method of claim 1, wherein the composition is added to the wash fluid. 13. The method of claim 5, wherein the removing liquor and water from the alumina trihydrate bearing slurry comprises filtration. 14. The method of claim 5, wherein the wash fluid is added to the slurry before the removing, during the removing, after the removing, or combinations thereof. 15. The method of claim 5, wherein the removing liquor and water from the alumina trihydrate bearing slurry comprises gravity separation, pressure separation, vacuum separation, or combinations thereof.
02/26/2014 00:00:00
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1.4.28 Belt filter press
Amendment addition system and method for twin belt press filter
The above description of embodiments of this invention is intended to be illustrative and not limiting. Other embodiments of this invention will be obvious to those skilled in the art in view of the above disclosure.
1. A belt press cake dewatering device comprising a gravity drain zone deck of fixed width and fixed length, a first porous belt movably extending across said gravity drain zone deck from a first end to a second end thereof for forming partially dewatered cake on said first porous belt, a feed box adjacent said first end of said drain zone deck for introducing a slurry on said first porous belt, a second porous belt in proximity to said first belt at said second end of said drain zone deck, said first and second belts forming juxtaposed twin belts for receiving partially dewatered cake between said belts, said belts extending downstream of said drain zone around a series of press rollers to further dewater cake from said drain zone deck, said device further comprising: a feed hopper having a supply consisting essentially of a solid absorbent particulate slurry amendment therein; means extending above the juxtaposition of said first and second belts for gravity depositing a band of said slurry amendment from said hopper on and across said partially dewatered cake downstream of said second end of said drain zone deck at said juxtaposition of said first and second belts; and means for mixing said slurry amendment with said partially dewatered cake while said juxtaposed belts are receiving said partially dewatered cake to change the rheology and improve dewaterability of the resultant mixture thereof between said belts. 2. The device of claim 1 further comprising wedge means for compressing said resultant mixture between said belts downstream of said drain zone deck, and before said press rollers. 3. The device of claim 1 further comprising means for allowing partially dewatered cake to drop from said first belt and in which said slurry amendment-containing hopper includes an exit slot extending essentially across the width of said drain zone deck adjacent said second end of said drain zone deck and positioned to gravity feed slurry amendment from said hopper onto said partially dewatered cake as said partially dewatered cake drops from said first belt. 4. The device of claim 3 including a metering valve for controlling the feed rate of slurry amendment from said exit slot. 5. The device of claim 1 further comprising a means for mixing an additional amount of slurry amendment with said dewatered cake, said means for mixing being positioned downstream of at least a first of the series of press rollers and further dewatering said cake. 6. The device of claim 5 further comprising means for scraping furthered dewatered cake from said second belt downstream of the first of the series of press rollers; means for diverging said first belt from said second belt to form a mixing chamber downstream of said means for scraping; and means in said mixing chamber for feeding additional slurry amendment onto scraped further dewatered cake in said mixing chamber. 7. The device of claim 6 in which said means for feeding comprises an auger an d slotted feed tube extending transverse to and across the width of said first belt. 8. The device of claim 7 further comprising a paddle mixer in said mixing chamber for mixing said additionally slurry amendment exiting said feed tube with said scraped further dewatered cake. 9. The device of claim 6 wherein said means for scraping and said mixing chamber is upstream of a further one of said series of press rollers. 10. A belt press cake dewatering device comprising a gravity drain zone deck of fixed width and fixed length, a first porous belt movably extending across said gravity drain zone deck from a first end to a second end thereof for forming partially dewatered cake on said first porous belt, a feed box adjacent said first end of said drain zone deck for introducing a slurry on said first porous belt, a second porous belt in proximity to said first belt at said second end of said drain zone deck, said first and second belts forming juxtaposed twin belts for receiving partially dewatered cake between said belts, said belts extending downstream of said drain zone around a series of press rollers to further dewater cake from said drain zone deck, said device further comprising: a feed hopper having a supply of absorbent particulate slurry amendment therein; means for depositing a band of said slurry amendment from said hopper on and across said partially dewatered cake downstream of said second end of said drain zone deck at said juxtaposition of said first and second belts; means for mixing said slurry amendment with said partially dewatered cake to change the rheology and improve dewaterability of a resultant mixture thereof between said belts; and means for scraping said partially dewatered cake from said first porous belt, and first means for guiding said second belt, said means for scraping and said first means for guiding together forming a mixing chamber between said belts for mixing said slurry amendment and partially dewatered cake. 11. The device of claim 10 further including a paddle mixer in said mixing chamber, said mixer extending transverse to and across the width of said first belt, to mix said slurry amendment with said partially dewatered cake. 12. The device of claim 11 further comprising second means for guiding said second belt, downstream from said first means for guiding, into parallelism with said first belt to confine mixed dewatered cake and slurry amendment therebetween. 13. A method of dewatering a slurry in a filter having two porous belts, a gravity drain zone, and a series of belt press rollers downstream of said drain zone, comprising the steps of: (a) passing a first of said belts over said drain zone from a first end of said drain zone to a second end thereof; (b) feeding said slurry to said first of said belts at a position adjacent said drain zone first end, said belt carrying said slurry to said drain zone to initially gravity drain the slurry and form a partially dewatered cake on said first belt; (c) convergingly bringing a second of said belts into parallelism with said first belt; (d) feeding said partially dewatered cake into a nip formed between said converging belts; (e) feeding an amendment consisting essentially of a solid absorbent particulate material onto and mixing said particulate material into said partially dewatered cake as the partially dewatered cake is fed into said nip for further improving the dewaterability of said partially dewatered cake; and (f) pressing the resultant mixture of amendment and partially dewatered cake between said converged parallel belts to further dewater said partially dewatered cake and slurry. 14. The method of claim 13 further comprising dropping said partially dewatered cake off said first belt immediately downstream of said drain zone; and gravity feeding said amendment onto said partially dewatered cake as said partially dewatered cake is fed into said nip. 15. The method of claim 14 further comprising providing a paddle mixer for mixing said dropped partially dewatered cake and said gravity-fed amendment in a zone between said belts and above said nip. 16. The method of claim 13 further comprising recycling a portion of said further dewatered cake from step (f) to step (d). 17. The method of claim 13 further comprising leaching said cake between said belts downstream of said gravity drain zone with liquid-containing amendment such that liquid in said amendment displaces remaining pregnant liquor in said dewatered cake, thereby effecting improved overall recovery of the pregnant liquor by this leaching step. 18. The method of claim 13 in which said amendment comprises a fibrous absorbent dry material. 19. The method of claim 18 in which said amendment is sawdust having a particle range of from 4 to 60 mesh. 20. A method of dewatering a slurry in a filter having two porous belts, a gravity drain zone, and a series of belt press rollers downstream of said drain zone, comprising the steps of: (a) passing a first of said belts over said drain zone from a first end of said drain zone to a second end thereof; (b) feeding said slurry to said first of said belts at a position adjacent said drain zone first end, said belt carrying said slurry to said drain zone to initially gravity drain the slurry and form a partially dewatered cake on said first belt; (c) convergingly bringing a second of said belts into parallelism with said first belt; (d) feeding said partially dewatered cake into a nip formed between said converging belts; (e) feeding and mixing an absorbent particulate amendment onto and into said partially dewatered cake as the partially dewatered cake is fed into said nip for further improving the dewaterability of said partially dewatered cake; and (f) pressing the resultant mixture of amendment and partially dewatered cake between said converged parallel belts to further dewater said partially dewatered cake and slurry; (g) wherein pressing of said partially dewatered cake and amendment between said belts is by action of said press rollers to further dewater said dewatered cake; (h) diverging said belts from each other downstream of at least one of said press rollers to form a mixing zone between said belts; (i) mixing said further dewatered cake with additional amendment in said mixing zone; and (j) press rolling a resultant second mixture of said further dewatered cake and said additional amendment between said belts to further dewater said second mixture.
03/22/1988 00:00:00
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1.4.29 Belt filter press
Dewatering process

1. A process of dewatering an aqueous sewage sludge suspension employing a flocculating system comprisingi.) treating the suspension with a flocculating amount of a first flocculant having a molecular weight of at least one million and a dewatering amount of a second flocculant, which second flocculant is in the form of particulates,ii.) thickening the treated suspension of step i.) by release of free water,iii.) mixing the thickened suspension, wherein the second flocculant particulates are distributed throughout the thickened suspension of step ii.), using mixing equipment, andiv.) subjecting the suspension to mechanical compression dewatering to form a cake, wherein the first flocculant brings about flocculation and assists thickening of the suspension and the second flocculant further dewaters the suspension,characterised in that the second flocculant is a water-soluble or water swellable polymer formed from 80 to 100% by weight methyl chloride quaternary ammonium salt of dimethyl amino ethyl (meth)acrylate and 0 to 20% by weight acrylamide of intrinsic viscosity between 3 and 10 dl/g that is mixed into the suspension in the form of a water-soluble or water swellable particulate polymer having a particle diameter of at least 50 microns, wherein the first and second flocculants are not counterionic and the first flocculant is cationic acrylamide polymer. 2. A process according to claim 1 in which the compression dewatering employs an apparatus selected from the group consisting of belt press, filter press, screw press and centrifuge. 3. A process according to claim 1 in which the first flocculant and second flocculant are added substantially simultaneously. 4. A process according to claim 1 in which the first flocculant and second flocculant are combined into a single composition. 5. A process according to claim 4 in which the single composition is a particulate polymer product in which the first flocculant comprises particles having a diameter below 10 microns. 6. A process according to claim 1 in which the second flocculant comprises polymeric particles having a coating applied to the surface. 7. A process according to claim 6 in which the coating is a silicone. 8. A process according to claim 6 in which the coating is a water-soluble wax. 9. A process according to claim 1 in which the second flocculant is introduced into the suspension in form of a slurry in a liquid. 10. A process according to claim 9 in which the liquid is polyethylene glycol. 11. A process according to claim 1, wherein the second flocculant is a polymer of intrinsic viscosity between 4 and 10 dl/g. 12. A process according to claim 1, wherein the second flocculant is a particulate polymer having a particle diameter between 100 and 800 microns. 13. A process according to claim 1, wherein thickened suspension in step ii.) is a semi solid sludge paste.
02/28/2005 00:00:00
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1.4.30 Belt filter press
Improved process to transfer a ligno-cellulosic feedstock
It is disclosed a process to transfer a ligno-cellulosic feedstock from a low pressure zone to a high pressure zone. A slurry the ligno-cellulosic feedstock is first provided, which is then subjected to a multi-step liquid removal process comprising draining by gravity at least a portion of the free liquid; removing a first portion of the capillary liquid in a low pressure zone by continuously compressing a stream of the ligno-cellulosic feedstock to reach a moisture content in a first target range; removing a second portion of the capillary liquid by shearing and compressing the ligno-cellulosic stream in a plug forming device, to form a ligno-cellulosic feedstock plug having a moisture content in a second target range at an outlet of the plug forming device connected to the high pressure zone. In the removal of the first portion of the capillary liquid, at least one first compression device continuously compresses the stream of the drained ligno-cellulosic feedstock to a first control pressure, while conveying the stream of the drained ligno- cellulosic feedstock in a flow direction of a belt filter press.
A continuous process to transfer a ligno-cellulosic feedstock from a low pressure zone to a high pressure zone, said ligno-cellulosic feedstock having a starting liquid retention capability and a starting moisture content which is less than a first target range, the process comprising the steps of: a. treating the ligno-cellulosic feedstock with a treatment liquid comprising water at a treatment temperature between 60 °C and 160°C, and for a treatment time sufficient to create a slurry comprising a free liquid and a treated ligno-cellulosic feedstock, wherein the treated ligno-cellulosic feedstock has a liquid retention capability which is greater than the starting liquid retention capability and a moisture content which is greater than the first target range; b. Draining by gravity at least a portion of the free liquid to produce a drained ligno-cellulosic feedstock containing a capillary liquid; c. Removing a first portion of the capillary liquid in the low pressure zone by compressing a stream of the drained ligno-cellulosic feedstock at a compression ratio in a range of greater than 1:1 to 12:1, to produce a dewatered ligno-cellulosic feedstock stream having a moisture content in the first target range which is from 65% to 85%; d. Removing a second portion of the capillary liquid from the dewatered ligno-cellulosic feedstock stream by shearing and compressing the dewatered ligno-cellulosic feedstock stream in a plug forming device, to form a ligno-cellulosic feedstock plug having a,moisture content in a second target range which is from 40% to 60% at an outlet of the plug forming device connected to the high pressure zone. The process of claim 1, wherein the stream of,the drained ligno-cellulosic feedstock is continuously compressed to at least one control pressure. The process of claim 2, wherein at least one first compression device continuously compresses the stream of the drained ligno-cellulosic feedstock to a first control pressure, while conveying the stream of the drained ligno- cellulosic feedstock in a flow direction of a belt filter press. The process of any of claims 2 to 3, wherein the first,control pressure is a value in a range selected from the groups consisting of 100 kPa to 10,000 kPa, 200 kPa and 9,000 kPa, and 500 kPa to 8,000 kPa. The process of any of claims 3 to 4, wherein there are more than one compression devices distributed along the flow direction, each having a control pressure. The process of claim 5, wherein the control pressure of the compression devices increases along the flowing direction. The process of any of claims 1 to 6, wherein the moisture content of the dewatered ligno-cellulosic feedstock stream is time-stable. The process of any of claims 1 to 7, wherein the treatment of the ligno- cellulosic feedstock is conducted for a treatment time which is in a range selected from the group consisting of 5 minutes to 3 hours, from 10 minutes to 2hours, 30 minutes to 1 hour. The process of 8, wherein the lignocellulosic feedstock comprises carbohydrates and the percent amount of carbohydrates solubilized in the thermal treatment is less than a value selected from the group consisting of 10%, 5%, 3%, 2% and 1% by weight. The process of any of claims 1 to 9, wherein the treatment of the ligno- cellulosic feedstock of step a) occurs in a treatment vessel at atmospheric pressure at a temperature which is less than 100°C. The process of claim 10, wherein the low pressure zone is at atmospheric pressure. The process of any of claims 1 to 9, wherein the treatment of the ligno- cellulosic feedstock of step a) occurs in a treatment vessel at a treatment temperature greater than 80°C and the treatment vessel is pressurized at a pressure greater than the low pressure zone and less than the high pressure zone. The process of claim 12, wherein the low pressure zone is at atmospheric pressure. The process of claim 12, wherein the low pressure zone is pressurized at a pressure greater than 1 bar and less than a value selected from the group consisting of 600 kPa, 400 kPa, and 200 kPa. The process of any of claims 1 to 14, wherein the pressure of the high pressure zone is a value in a range selected from the group consisting of greater than 600 kPa to 4,000 kPa, from 1,000 kPa to 2,600 kPa, and from 1,200 kPa to 2,000 kPa. The process of claims 1 to 15, wherein the percent amount of free liquid in the drained ligno-cellulosic feedstock is less than a value selected from the group consisting of 30%, 20%, 10% and 5% on wet basis. The process of any of claims 1 to 16, wherein the first target range is selected from the group consisting of from 70% to 80%, and from 75% to 78% by weight on a wet basis. The process of any of claims 1 to 17, wherein the plug forming device has a compression ratio in a range selected from the group consisting of from greater than 1:1 to 8:1, from 1.1:1 to 5:1, from 1.5:1 to 3:1, and from 1.5:1 to 2.5:1. The process of any of claims 1 to 18, wherein the second target range is selected from the group consisting of from 45% to 50%, and from 47% to 53% by weight on a wet basis. The process of any of claims 1 to 19, wherein the temperature of the stream of the drained ligno-cellulosic feedstock during compression is in a range selected from the group consisting of 10°C to 160°C, from 50°C to 100°C, and from 60°C to 90°C. The process of any of claims 1 to 20, wherein the ligno-cellulosic feedstock is a straw. The process of any of claims 1 to 21, wherein the ligno-cellulosic feedstock is selected from the group consisting of wheat straw, rice straw, barley straw, and bagasse. The process of any of claims 1 to 22, wherein the stream of the drained lignocellulosic feedstock has a flow rate which is greater than 5 ton/hour on a dry basis.
02/09/2015 00:00:00
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1.4.31 Belt filter press
Partial oxidation of sewage sludge
An improved process for the low-cost disposal of noxious sewage sludge in a safe way without polluting the environment. In the process, sewage sludge having a solids content of about 0.5 to 20 wt.% is concentrated by pressing in a belt filter press, optionally followed by pressing in a high intensity press. It was unexpectedly found that the morphology of the resulting dewatered sewage sludge is changed by such mechanical treatment so that slurries with higher concentrations of solids are achieved. The dewatered sewage sludge is heated, flash evaporated and/or centrifuged, and mixed with a supplemental fuel e.g., liquid hydrocarbonaceous and/or solid carbonaceous fuel to produce a pumpable fuel slurry having a total solids content in the range of about 50 to 70 wt.% and comprising about 10 to 40 wt.% dewatered sewage sludge and having a higher heating value in the range of about 5,000 to 14,000 BTU/Lb. The fuel slurry may be reacted by partial oxidation in a conventional gasifier to produce synthesis gas and/or fuel gas. The thermal energy in hot by-product steam and flue gas streams are used to heat the dewatered sewage sludge. In one embodiment, the pumpable slurry of dewatered sewage sludge and supplemental fuel is burned by complete combustion in a furnace or incinerator for the production of steam.
A process for the production of fuel from sewage sludge comprising: (1) concentrating sewage sludge containing about 0.5 to 20 wt.% solids in a belt filter pressing zone to produce highly dewatered sewage sludge comprising about 15 to 65 wt.% solids, and separating excess water from said dewatered sewage sludge; (2) heating the sewage sludge from (1) in a reaction zone at a heat treating temperature in the range of about 130°F to 200°F in the absence of air for a residence time of about 1 to 20 minutes and at atmospheric pressure, followed by heating at a heat treating temperature in the range of about 300°F to 650°F in the absence of air for a residence time of about 5 to 120 minutes and at a pressure which is at or above the vapor pressure of water at the heat treating temperature to cause decarboxylation and dehydration of the sewage sludge and to produce a pumpable aqueous slurry of sewage sludge; (3) reducing the pressure and corresponding temperature of the aqueous slurry of sewage sludge from (2) in a flash evaporization zone to a pressure in the range of about atmospheric pressure to the saturated vapor pressure of water at the temperature in said flash evaporation zone which is in the range of about 200°F to 400°F thereby evaporating and separating sufficient water from said sewage sludge to provide a pumpable slurry of dewatered sewage sludge having a solids content in the range of about 30 to 70 wt.% and having a higher heating value (HHV) in the range of about 5,000 to 9,500 BTU/LB; (4) mixing the slurry of dewatered sewage sludge from (3) with a supplemental fuel thereby providing a pumpable slurry having a total solids content in the range of about 50 to 70 wt.% and comprising about 10 to 40 wt.% dewatered sewage sludge and having a higher heating value in the range of about 5,000 to 14,000 BTU/LB. A process according to Claim 1 including (5) partially oxidizing the pumpable slurry from (4) with a stream of free-oxygen containing gas and a temperature moderator in the reaction zone of a gas generator at a temperature in the range of about 1800°F to 3000°F and a pressure in the range of about 1 to 30 atmospheres to produce a hot raw effluent stream of at least one gas from the group consisting of synthesis gas, reducing gas and fuel gas. A process according to Claim 1 wherein the pumpable slurry fuel from (4) is burned by complete combustion in a furnace or incinerator. A process according to any one of Claims 1 - 3 wherein the sewage sludge in (1) is concentrated by a surface pressure in the range of about 20 to 200 psi which is applied to said sewage sludge for a period in the range of about 1/2 to 60 minutes. A process according to any one of Claims 1 - 4 wherein the sewage sludge in (1) is concentrated by a combination of continuous belt pressure filtering and centrifuging. A process according to any one of Claims 1 - 5 wherein the pumpable slurry of dewatered sewage sludge from (3) is introduced into a centrifuging zone to remove water prior to step (4). A process according to any one of Claims 1 - 3 wherein said sewage sludge is concentrated in (1) by sequentially pressing said sewage sludge in a continuous belt pressure filtering zone with a first pressing at a surface pressure in the range of about 20 to 200 pounds per square inch for a period in the range of about 1/2 to 60 minutes followed by a second pressing with a surface pressure of about 200 pounds per square inch for a similar period as said first pressing. A process according to Claim 7 wherein additional dewatering is provided by heating the sludge to a temperature in the range of about 100°C to 140°C during said second pressing. A process according to any one of Claims 1 - 8 wherein additional dewatering is provided by pressing in (1) said sewage sludge while in admixture with a filter aid having particle size of less than 2 mm. A process according to Claim 9 wherein said filter aid is selected from the group consisting of coal fines and CaCO₃. A process according to any one of Claims 1 - 10 wherein the sewage sludge in (2) is heated to the desired temperature by indirect heat exchange with steam or synthesis gas.
01/21/1993 00:00:00
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1.4.32 Belt filter press
Pretreatment process of a ligno-cellulosic feedstock

1. A continuous pretreatment of a ligno-cellulosic feedstock having a starting liquid retention capability and a starting moisture content which is less than a first target range, the process comprising the steps of: a. providing a slurry of the ligno-cellulosic feedstock; b. draining by gravity at least a portion of a free liquid of the slurry to produce a drained ligno- cellulosic feedstock containing a capillary liquid; c. removing a first portion of the capillary liquid in a low pressure zone operating at atmospheric pressure by compressing a stream of the drained ligno-cellulosic feedstock at a compression ratio in a range of greater than 1:1 to 12:1, to produce a dewatered ligno-cellulosic feedstock stream having a moisture content in the first target range which is from 65% to 85%; d. removing a second portion of the capillary liquid from the dewatered ligno-cellulosic feedstock stream by shearing and compressing the dewatered ligno-cellulosic feedstock stream in a plug forming device, to form and advance a ligno- cellulosic feedstock plug into a high pressure reactor operating in the range of greater than 600 kPa to 4,000 kPa connected to an outlet of the plug forming device plug; e. subjecting the ligno-cellulosic feedstock to a hydrothermal treatment in the presence of water in liquid or steam phase or a mixture thereof at a hydrothermal temperature in the range of 160° C. to 250° C. for a hydrothermal time in the range of 10 sec. to 2 hour to produce a pretreated lignocellulosic feedstock. 2. The process of claim 1 , wherein the process further comprises steam exploding the pretreated lignocellulosic feedstock. 3. The process of claim 1 , wherein providing the slurry of the ligno- cellulosic feedstock comprises the step of treating the ligno-cellulosic feedstock treatment in the presence of water in liquid or steam phase at a temperature between 60° C. and 160° C., and for a time sufficient to create a slurry comprising a free liquid and a treated ligno-cellulosic feedstock, wherein the treated ligno-cellulosic feedstock has a liquid retention capability which is greater than the starting liquid retention capability. 4. The process of claim 3 , wherein the treatment of the ligno-cellulosic feedstock is conducted for a time which is in a range selected from the group consisting of 5 minutes to 3 hours. 5. The process of claim 3 , wherein the lignocellulosic feedstock comprises carbohydrates and the percent amount of carbohydrates solubilized in the thermal treatment is less than 10 by weight. 6. The process of claim 1 , wherein providing the slurry of the ligno- cellulosic feedstock comprises the step of soaking the ligno-cellulosic feedstock in a soaking liquid comprising water a soaking temperature between 30° C. and 100° C., and for a soaking time sufficient to create a slurry comprising a free liquid and a soaked ligno-cellulosic feedstock without altering the starting liquid retention capability, wherein the soaked ligno- cellulosic feedstock has a moisture content which is greater than 80% of the starting liquid retention capability. 7. The process of claim 6 , wherein the ligno-cellulosic feedstock comprises a ligno-cellulosic component and non-ligno-cellulosic water soluble compounds, and the free liquid comprises water and water soluble species derived from the non ligno-cellulosic water soluble compounds. 8. The process of claim 6 , wherein the soaking temperature is in a range selected from the group consisting of 40° C. to 99° C. 9. The process of claim 6 , wherein the soaking time is in a range selected from the group consisting of 30 seconds to 300 minutes. 10. The process of claim 1 , wherein the stream of the drained ligno- cellulosic feedstock is continuously compressed to at least one control pressure. 11. The process of claim 10 , wherein at least one first compression device continuously compresses the stream of the drained ligno-cellulosic feedstock to a first control pressure, while conveying the stream of the drained ligno- cellulosic feedstock in a flow direction of a belt filter press. 12. The process of claim 10 , wherein the first control pressure is a value in a range of 100 kPa to 10,000 kPa. 13. The process of claim 10 , wherein there are more than one compression devices distributed along the flow direction, each having a control pressure. 14. The process of claim 13 , wherein the control pressure of the compression devices increases along the flowing direction. 15. The process of claim 1 , wherein the first target range is from 70% to 80. 16. The process of claim 1 , wherein the hydrothermal temperature of step f) is a value in a from 170° C. to 230° C. 17. The process of claim 1 , wherein the hydrothermal time of step f) is a value in a range consisting of from 30 seconds to 1 hour. 18. The process of claim 1 , wherein the ligno-cellulosic feedstock is a straw. 19. The process of claim 1 , wherein the ligno-cellulosic feedstock is selected from the group consisting of wheat straw, rice straw, barley straw, and bagasse.
01/28/2016 00:00:00
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1.4.33 Belt filter press
Process for production of lignin fuel, ethyl alcohol, cellulose, silica/silicates, and cellulose derivatives from plant biomass
Note #2 344.4 lbs of the caustic solution forms the caustic oxide.
1. A method for producing lignin fuel, silica/sodium oxide, cellulose, and cellulose derivatives from plant biomass comprising the steps of placing plant biomass in a hammermill or ball mill and grinding the plant biomass to 45 to 55 mesh, feeding the reduced size biomass into the first counter-current extractor, admixing the biomass with a mild acid solvent solution of acetic, carbonic, hydrochloric, phosphoric, or sulfuric acid at a temperature between 40 and 60 degrees C. and a residence time between 50 and 70 minutes, withdrawing a solvent stream from the first counter-current extractor containing 5-carbon sugars, soluble salts, soluble plant proteins, and soluble polypeptides which is passed to a fermentation tank where the 5-carbon sugars are fermented to ethanol, withdrawing a solid material stream from the first counter-current extractor and passing the solid material stream through a belt-press filter, dewatering the solid material to between 70% and 80% total solids, and feeding the dewatered solid material stream into a second counter-current extractor, admixing the solid material with a caustic hydroxide solution, dissolving the lignin and silica, withdrawing a solvent stream from the second counter-current extractor containing the lignin and caustic silicate and passing the solvent to an ultrafiltration membrane system, separating and concentrating the lignin from the solvent containing the caustic silicate solution, withdrawing from the ultrafiltration membrane unit a caustic silicate solution whereby a silica caustic oxide solution is produced, withdrawing between 10% and 20% of the caustic silicate solution from the ultrafiltration membrane unit and sending the caustic silicate solution to the caustic solvent added to the second counter-current extractor as a feed-back solvent, withdrawing the solid stream from the second counter-current extractor and passing the solid stream to a washing centrifuge, withdrawing the solid stream from the washing centrifuge and passing the solid to a belt-press filter dewatering the solid to 75% total solids, withdrawing the solid from the belt-press filter and passing the solid to a tank wherein the solid cellulose material is converted to a glucose stream using acid hydrolyzing enzymes, withdrawing the glucose liquid stream from the hydrolyzing solution and passing the glucose stream to a fermentation tank wherein the glucose is converted to ethanol, carbon dioxide, and water, withdrawing an ethanol stream from the fermentation tank and passing the ethanol solution to a distillation unit, withdrawing 200 proof (100%) ethanol stream from the distillation unit, passing the ethanol stream to a mixing tank wherein the lignin is mixed with the ethanol in a mixture ratio of 3.8 parts ethanol and 1.0 part lignin (weight/weight) ratio, withdrawing the solid from the fermentation tank consisting of spent fermentation organisms and sending these solids to dewatering and drying whereby producing a high protein animal feed, withdrawing the ethanol-lignin mixture from the mixing tank thereby producing a high energy petroleum-type fuel. 2. A method according to claim 1 wherein lignin and ethanol are mixed in a ration between 3.0 parts ethanol to 1.0 part lignin and 3.8 parts ethanol to 1.0 part lignin (weight/weight), thereby producing a petroleum-like fuel. 3. A method according to claim 1 of wherein the plant biomass is selected from the group consisting of barley straw and barley hulls; corn stover and corn cobs; cotton stalks, cotton bowls, cotton gin mill blow wastes; forest slashings and saw mill wastes; rice straw and rice hulls; wheat straw and wheat hulls; or yard and orchard clippings. 4. A method according to claim 1 wherein the lignin extraction solvent comprises sodium hydroxide or potassium hydroxide as the solvent for extraction of lignin and silica, wherewith the solvent is sent to an ultrafiltration membrane system wherein the lignin is separated and concentrated and the silica/caustic oxide passes through the membrane. 5. A method according to claim 1 wherein the acid used to adjust the pH of the extracting solvent in the first extractor is carbonic, hydrochloric or sulfuric.
09/16/1996 00:00:00
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1.5 Rotary press

0

A Rotary Press works at a low speed of rotation of screen plates for solid-liquid separation. **Highlights:** * Originally developed by a Canadian governmental agency for **dewatering industrial sludges** such as paper pulp, the **rotary press technology** has been found to compare favourably with conventional dewatering technologies, in terms of cake dryness and suspended solids capture rates.[ \[Art. #ARTNUM\]](#article-96279-2513865741) * An apparatus for extracting a liquid by pressing a humid mass, said apparatus comprising at least one extraction channel for liquid removal \[...\] extraction channel is part of a rotary press.[ \[Art. #ARTNUM\]](#article-96279-US7166229B2) * Patent **Fournier International** * Analyses were conducted to determine the effects of solid-liquid separation techniques and biological processing on the characteristics and energy content of **swine manure**. \[...\] Rotary press separation with **polymer flocculation** produced a solid with the largest dry basis HHV, 9470 Btu/ lb, followed by belt separation (8782 Btu/lb), and screen separation (7191 Btu/lb).[ \[Art. #ARTNUM\]](#article-96279-2063196582) * A method of reducing an amount of energy needed for processing streams in an agricultural production facility \[...\] dewatering the liquid with the insoluble solids stream post liquefaction by using a rotary press to produce 1) a liquid with particles stream and 2) insoluble solids, which have a solids content of about **10% to about 70% solids**[ \[Art. #ARTNUM\]](#article-96279-US10260031B2) * Patent ICM inc * ICM inc. cooperates with Fournier International [\[web\]](https://www.fournierdewatering.com/fournier-rotary-press-is-a-success-in-ethanol-industry-with-icm/) * A method and apparatus for treating **liquid waste water sludge** after its generation and separation from the waste liquid involves propelling a plurality of separate streams of sludge via, for instance, a **rotor** (37) and then forcibly impacting sludge particles and microbial cells contained in the propelled streams of sludge against a contact surface such as a stator (59), for recirculation of sludge along toroidal paths (62) and (64), to thereby **fragment the particles** into smaller sized particles and break apart the organic cells. As a result of such a fragmentation process, **water** located in the pores of the sludge particles **is released**, thereby enhancing a subsequent dewatering process performed on the sludge.[ \[Art. #ARTNUM\]](#article-96279-1538660948) * Patent [Kady International](https://www.kadyinternational.com/) * Seems to be milling device

1.5.1 Rotary press
Apparatus and Method for Treatment of Waste Water Sludge
A method and apparatus for treating liquid waste water sludge after its generation and separation from the waste liquid involves propelling a plurality of separate streams of sludge via, for instance, a rotor (37) and then forcibly impacting sludge particles and microbial cells contained in the propelled streams of sludge against a contact surface such as a stator (59), for recirculation of sludge along toroidal paths (62) and (64), to thereby fragment the particles into smaller sized particles and break apart the organic cells. As a result of such a fragmentation process, water located in the pores of the sludge particles is released, thereby enhancing a subsequent dewatering process performed on the sludge. The destruction of the cells permits a subsequent solids digestion process to work more efficiently, while also permitting a more complete conversion to dissolved sugars, proteins and carbon dioxide.
02/17/1993 00:00:00
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1.5.2 Rotary press
Effect of Solid Separation and Composting on the Energy Content of Swine Manure
Animal manure represents a significant source of renewable bioenergy. In order to utilize current thermochemical energy conversion processes, a dry material (more than 90% total solids) is recommended. Solid-liquid separation can serve as a useful pretreatment of animal manure as a dewatering tool. Analyses were conducted to determine the effects of solid-liquid separation techniques and biological processing on the characteristics and energy content of swine manure. Specifically, four swine manure materials were examined: 1) homogenized house effluent, 2) separated solids from a belt, screen, and polymer injecting-rotary press solid-liquid separators, 3) anaerobic lagoon sludge, and 4) biologically processed solids from a composting facility. In addition to dewatering the aqueous waste stream, solid-liquid separation generated solids with similar volatile solids content yet different in fixed carbon, ash, and higher heating value (HHV). Rotary press separation with polymer flocculation produced a solid with the largest dry basis HHV, 9470 Btu/ lb, followed by belt separation (8782 Btu/lb), and screen separation (7191 Btu/lb). All of these solids had larger HHV than the homogenized flushed manure house effluent solids HHV (6441 Btu/lb). The increase in HHV is partially attributed to solid-liquid separation reducing the ash content of dried solids between 48 to 80%.
01/01/2007 00:00:00
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1.5.3 Rotary press
Effective, economic and easy dewatering of sludges
Originally developed by a Canadian governmental agency for dewatering industrial sludges such as paper pulp, the rotary press technology has been found to compare favourably with conventional dewatering technologies, in terms of cake dryness and suspended solids capture rates. Tony Clutten, Delkor Ltd, UK, which is now marketing the rotary press in the UK and Ireland, explains how the technology works and presents performance data.
01/01/2003 00:00:00
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1.5.4 Rotary press
Enhanced sludge dewatering based on the application of high-power ultrasonic vibration
Abstract Interest in producing heat and power using municipal wastewater sewage sludge as a fuel is increasing worldwide. Since its water content is initially high, sludge must be dewatered and further dried if it is to serve as an effective fuel for combustion. However, to maximize net energy production, the drying processes must use as little energy as possible. The water content in sewage sludge comprises both unbound and bound water. Unbound water content is typically extracted using a number of mechanical dewatering techniques. In terms of total solids content (TS), dewatering processes can take sludge from an initial 3–5% to a more solid 25–45% TS with minimal energy expenditure. However, this level of dryness is not sufficient for effective combustion. To produce an effective fuel, TS levels must be increased. Achieving high level of dryness involves removing any remaining unbound water and substantial bound water content as well. Heat is normally applied to accomplish this by changing the phase of the water from liquid to vapor. Although dewatering is energy-efficient, thermal drying is not. The energy used to thermally dry sludge can be two orders of magnitude greater than the energy used for dewatering. Therefore, to expend as little energy as possible to achieve the needed dryness, conventional dewatering processes clearly must be improved. This paper describes work carried out to identify promising ways to efficiently enhance the dewatering and drying of sewage sludge. Available dewatering approaches were reviewed and experiments were carried out to examine the relative effects of temperature, atmospheric pressure, and high-power ultrasound. The high-power ultrasound approach seemed to be particularly effective. The mechanisms involved include atomization, microstructural effects, cavitation, and the sponge effect, which work to reduce both internal and external resistances. Applied in the right way, ultrasound could become a very effective way to enhance mechanical dewatering.
03/01/2018 00:00:00
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1.5.5 Rotary press
Method for treatment of waste water sludge
A method for treating liquid waste water sludge after its generation and separation from the waste liquid involves forcibly impacting sludge particles and microbial cells against a contact surface to thereby fragment the particles into smaller-sized particles and break apart the organic cells. As a result of such a fragmentation process, water located in the pores of the sludge particles is released, thereby enhancing a subsequent dewatering process performed on the sludge. The destruction of the cells permits a subsequent solids digestion process to work more efficiently, while also permitting a more complete conversion to dissolved sugars, proteins and carbon dioxide.
11/24/1992 00:00:00
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1.5.6 Rotary press
Screening study on flocculant for night soil dewatering
Separation of the solid and liquid is a prerequisite for sustainable utilization of night soil or manure.Floculant must be added to improve the poor dewatering capacity.Five kinds of flocculant have been comparatively studied on the effects of night soil settlement and dewatering.Two preferred polyacrylamide were selected to test on line.decanter centrifuge and rotary press were used as dewatering equipment.The results showed that cationic high polymer flocculant with molecular weight greater than 5 million should be chosen instead of inorganic coagulant to flocculate night soil.Dewatering effect of FO4000 of SNF company is superior to others.The optimum dosage of FO4000 is 3~4 kg/t dry solids for decanter centrifuge and 5~7 kg/t dry solids for rotary press.
01/01/2002 00:00:00
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1.5.7 Rotary press
Method and apparatus for extracting liquid present in a humid mass

1. An apparatus for extracting a liquid by pressing a humid mass, said apparatus comprising at least one extraction channel for liquid removal, which extraction channel is provided with:at least one inlet for feeding the extraction channel with the humid mass to be treated;walls provided with holes for allowing liquid contained in the humid mass being pressed to evacuate from said extraction channel, the humid mass gradually becoming a dehydrated mass; andat least one outlet for discharging the dehydrated mass, in the form of a cake, obtained by pressing the humid mass in the extraction channel, the cake having a lower liquid content than the humid mass; wherein the outlet has a downstream end which is further provided with an opened portion in one or more of lateral sides of said downstream end and/or in a bottom of said downstream end, and wherein said downstream end is further provided in said opened portion with a device applying a level of constraints to the dehydrated mass in the channel to control the holding up the dehydrated humid mass arriving at said outlet, and wherein said device further comprises:a first device for measuring the entrainment force exerted by the friction generated, on said extraction channel, by the humid mass being dehydrated, and/or measuring of the pressure within the extraction channel and/or measuring of the pressure on the walls of said extraction channel; anda second device to regulate constraints to said dehydrated mass, at the outlet of said extraction channel, as a function of said entrainment force and/or pressure measured with said first system, for controlling the holding up of the dehydrated mass arriving at the outlet of the channel, and for managing the level of constraints generated to said dehydrated mass at the outlet of the extraction channel. 2. A system for extracting a liguid by pressing a humid mass wherein said system comprises a plurality of apparatuses as defined in claim 1. 3. A system for extracting a liguid by pressing a humid mass according to claim 2, wherein said apparatuses are operated by a single motor. 4. A apparatus according to claim 1, wherein said device is one of a gate type and a flap type. 5. A apparatus according to claim 1, wherein said device is adapted to be adjusted vertically. 6. An apparatus according to claim 1, wherein said extraction channel is part of a rotary press. 7. Method for dehydrating a humid mass wherein said humid mass is treated with an apparatus as defined in claim 1. 8. Method according to claim 7, wherein the humid mass to be dehydrated is selected in the group constituted by pulps resulting from paper industries, humid mass resulting from waste water treatment, mineral processing, agriculture and food processing, from fisheries, breweries, wineries, chemical processing, and oil industry. 9. Method according to claim 7, wherein the humid mass to be dehydrated has the ability to develop high friction at the outlet of an extracting and pressing apparatus, and/or for salting out the liquid phase. 10. A process for extracting a liquid from a humid mass, said process comprising the steps of:a) feeding with said humid mass an extracting zone, equipped with extracting means and with means for measuring the level of constraints generated in the extracting zone by the humid mass during its treatment;b) extracting at least part of the liquid present in the humid mass by pressing said humid mass;c) evacuating at least part of the extracted liquid from the extracting zone; andd) evacuating the mass with a reduced liquid content obtained in step b) from the extracting zone through an evacuation zone equipped with means for regulating the level of constraints generated by said mass with a reduced liquid content, when going through the evacuation zone; wherein the level of constraints in the evacuation zone is regulated with an apparatus as defined in claim 1. 11. A process for extracting a liquid from a humid mass according to claim 10, wherein the liquid represents from 0.1 to 22.0 weight percent of total weight of said humid mass. 12. A process for extracting a liquid from a humid mass according to claim 10, wherein the humid mass is selected in the group constituted by pulps resulting from paper industries, humid mass resulting from waste water treatment, mineral processing, agriculture and food processing, from fisheries, breweries, wineries, chemical processing, and oil industry. 13. A process for extracting a liquid from a humid mass according to claim 10, wherein the gain in dryness is of at least 5% as measured by the method AFNOR T97-001. 14. A process for extracting a liquid from a humid mass according to claim 13, wherein the gain in dryness is of at least 25%. 15. A process for extracting a liquid from a humid mass according to claim 10, wherein the extracting zone comprises means capable of generating a pressure on the humid mass and walls provided with holes for evacuating at least part the liquid contained in the humid mass being pressed against by the effect of the pressure. 16. A process for extracting a liquid from a humid mass according to claim 10, wherein the walls are equipped with means capable of measuring the pressure exerted on said wall by the humid mass during its treatment. 17. A process for extracting a liquid from a humid mass according to claim 10, wherein the extracting zone is equipped with means capable of measuring the pressure inside the humid mass during the dehydrating process. 18. A process for extracting a liquid from a humid mass according to claim 10, wherein the level of constraints in the outlet zone is controlled as a function of the physical parameter related to the pressure of the humid mass on the wall of the extracting zone. 19. A process for extracting a liquid from a humid mass according to claim 10, wherein the levels of constraints in the outlet zone is controlled by optimization of the various parameters measured in the extracting zone. 20. A process for extracting a liquid from a humid mass according to claim 10, wherein the gain in dryness is of at least 10%, as measured by the method AFNOR T97-001.
07/05/2002 00:00:00
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1.5.8 Rotary press
Optimized dewatering process for an agricultural production facility

1. A method of reducing an amount of energy needed for processing streams in an agricultural production facility, the method comprising: receiving a process stream of grain components, the process stream including a mixture of liquids and suspended solids; separating the suspended solids from the liquids using a paddle screen to form a liquid with insoluble solids stream; and dewatering the liquid with the insoluble solids stream post liquefaction by using a rotary press to produce 1) a liquid with particles stream and 2) insoluble solids, which have a solids content of about 10% to about 70% solids. 2. The method of claim 1 , wherein the process stream is obtained as a slurry from a liquefaction tank. 3. The method of claim 1 , wherein the insoluble solids have particle sizes that range from about 20 microns to about 1000 microns. 4. The method of claim 1 , further comprising drying the suspended solids. 5. The method of claim 1 , further comprising sending the liquid with particles stream to fermentation. 6. The method of claim 1 , further comprising sending the insoluble solids to be processed and to sell as a feed product, or sending the insoluble solids to be processed and mixed with syrup to sell as a feed product with syrup. 7. The method of claim 1 , further comprising sending the insoluble solids through a mechanical device to be further separated. 8. A method of reducing an amount of energy needed for processing streams in an agricultural production facility, the method comprising: receiving liquids and suspended solids in a process stream from the agricultural production facility; and dewatering the liquids and suspended solids in the process stream post liquefaction using a rotary press to produce 1) a liquid with particles stream and 2) insoluble solids having a solids content of greater than about 25% solids. 9. The method of claim 8 , wherein the liquids and suspended solids in the process stream comprise about 10% to about 38% solids content. 10. The method of claim 8 , wherein the liquid with particles stream comprises solids up to about 20% solids content. 11. The method of claim 8 , further comprising drying the insoluble solids having solids content greater than about 25%. 12. The method of claim 8 , further comprising separating the suspended solids from the liquids using a paddle screen prior to the dewatering. 13. A method comprising: receiving liquids and solids in a process stream up to about 38% solids content; and dewatering the liquids and solids in the process stream post liquefaction using a rotary press to produce 1) a liquid with particles stream having up to about 20% solids content and 2) insoluble solids having less than about 55% solids content. 14. The method of claim 13 , further comprising adding a chemical to the liquids and solids in the process stream prior to the dewatering. 15. The method of claim 13 , further comprising adding a liquid medium to the insoluble solids to remove additional components. 16. The method of claim 13 , further comprising spray or submerge washing the insoluble solids to remove additional amounts of components. 17. The method of claim 13 , further comprising separating the suspended solids from the liquids using a paddle screen prior to the dewatering.
12/01/2014 00:00:00
Link to Patent

1.6 Vacuum filtration

0

Dewatering methods using a vacuum filter. **Highlights:** * Clean and **energy-efficient rotary drum vacuum filtration** was selected to conduct **algae-dewatering**. \[...\] Optimal operating conditions and minimum dewatering cost were achieved by process optimization, and two **cost-sensitive zones** in operating the filtration were identified. The techno-economics showed that the dewatering cost can be further reduced by scaling up the process.[ \[Art. #ARTNUM\]](#article-96273-2052862252) * The working principle and process flow of the **HTG type ceramic filter** are described, as well as existing problems in the dewatering for **phosphate rock slurry**, and improvement measures. The production operation shows that the ceramic filter features high vacuity, **low water content** in the filter cake, and high yield. It is a piece of high-efficient, environmentally friendly and **energy-saving solid-liquid separation** equipment fit for wet milled phosphate rock powder.[ \[Art. #ARTNUM\]](#article-96273-2371162701) * **Fine coal slurry** is usually dewatered using a vacuum dewatering technique, providing a material with about 25 to 30 percent moisture. The process developed in this project will improve dewatering of fine (0.6mm) coal slurry to less than 20 percent moisture. Thus, thermal drying of dewatered wet coal will be eliminated. This will provide significant energy savings for the coal industry along with some environmental benefits. A 1% increase in recovery of coal and producing a filter cake material of less than 20 % moisture will amount to **energy savings** of 1900 trillion Btu/yr/unit.[ \[Art. #ARTNUM\]](#article-96273-1528742650) * The efficiency and the cost of dewatering lime and alum generated physical-chemical treatment sludge were developed utilizing a **continuous vacuum filter** and a solid bowl conveyor centrifuge. \[...\] **Vacuum filters are the least-cost approach** based on the results of the field studies. [\[Art. #ARTNUM\]](#article-96273-2275547947) * The **aeration-vacuum dewatering method** is a new kind of solid-liquid separate technique. The filter clogging problem in the routine vacuum dewatering procedure of sludge can be solved by the method. This method is used to **dewater the sewage sludge** in this paper.[ \[Art. #ARTNUM\]](#article-96273-2165618903) * **The sludge dewatering with aeration-vacuum (SDAV) method** is suit for treating the sludge with high water content and high clay content in the disposal site. The water in the sludge can be discharged out. The volume of the sludge can be reduced quickly, and the recycling of the land can be accelerated by this method. Most importantly, this technique is an efficient way to deal with clogging problems when pumping water from high water content, high clay content dredged sludge. [\[Art. #ARTNUM\]](#article-96273-2055512403) * A dewatering machine for reducing moisture of a polymer or an elastomer includes a generally solid barrel and a pair of screws disposed in the barrel. \[...\] The dewatering machine of claim 1, further comprising a **vacuum filter** connected to said barrel downstream of said at least one mechanical filter. \[...\] said polymer and said elastomer is selected from the group consisting of \[...\] thermoplastic rubber, and **biomass materials**.[ \[Art. #ARTNUM\]](#article-96273-US9316439B2) * Patent NFM Welding Engineers * The vacuum slurry dewatering machine provided by the invention has the advantages of full automation, **no addition of chemicals, high dewatering efficiency, low energy consumption**, clear filtrate, small occupied land area, etc.[ \[Art. #ARTNUM\]](#article-96273-2831860380) * Chinese patent * The utility model relates to an **energy-saving feeder of vacuum belt dewatering devices**, which comprises a blanking branch pipe fed with gypsum slurry \[...\] The utility model improves the dewatering efficiency of the vacuum belt dewatering devices[ \[Art. #ARTNUM\]](#article-96273-2825063928) * Chinese patent **Combinations:** * The objective of this research was to evaluate the dewatering of drinking water treatment sludge (DWTS) by **vacuum electro-osmosis dewatering (VEOD)** technology. \[...\] Vacuum filtration of 0.05 MPa can quickly dewater sludge and has **low energy consumption**, but can only remove free water and some pore water. The moisture content of the DWTS was reduced to below 79% by vacuum filtration technique alone. \[...\] Electro-osmosis optimized for the experimental conditions (0.05 MPa, 2.5 V/cm) began after vacuum filtration ceased, and drew pore water and surface adhesion water to the cathode, where it was expelled through vacuum filtration. The VEOD process removed all free water. In addition, pore water and surface adhesion water were reduced by 60.2% and 15.9%, respectively.[ \[Art. #ARTNUM\]](#article-96273-2465442171) **Combined with treatments:** * A method of treating clay contaminated ultra fine coal particles \[...\] to subdivide the size of the clay contaminant to clay platelets without flocculating the ultrafine coal particles; adding a sufficient amount of a **peptizing agent** to said slurry thereby peptizing the clay platelets to impart a state of discreetness in the aqueous slurry \[...\] The method according to claim 1 wherein said size separator comprises a filter and said filter is a vacuum filter.[ \[Art. #ARTNUM\]](#article-96273-US5236596) * Patent DTE Peptec

1.6.1 Vacuum filtration
A process for dewatering a coal slurry
Dewatering of coal slurry is improved by heating the slurry by passage through heat exchangers (15, 16) to 60 DEG C before feeding it to disc, belt or drum-type vacuum filter (11). The slurry is initially heated in heat exchanger (15) fed by hot filtrate from filter (11), and then in heat exchanger (16) by e.g. steam from line (17). Heating reduces the surface tension to produce a drier filter cake.
12/24/1985 00:00:00
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1.6.2 Vacuum filtration
Algae-dewatering using rotary drum vacuum filters: Process modeling, simulation and techno-economics
Abstract Clean and energy-efficient rotary drum vacuum filtration was selected to conduct algae-dewatering. The dynamic formation of an algal cake-layer on the filter surface was modeled by correlating the cake-layer permeability to the physical parameters of algae and cake-layer. The compressibility of algal cake-layer was taken into consideration in the modeling, and its effect on the algae-dewatering is discussed. The dewatering process was simulated to determine the process energy demand. Process economics were assessed considering the dewatering cost, which includes capital investment and energy cost and also labor, installation, maintenance and infrastructure. Optimal operating conditions and minimum dewatering cost were achieved by process optimization, and two cost-sensitive zones in operating the filtration were identified. The techno-economics showed that the dewatering cost can be further reduced by scaling up the process.
05/01/2015 00:00:00
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1.6.3 Vacuum filtration
Application of HTG Type Ceramic Vacuum Filter in Dewatering of Phosphate Rock Slurry
The working principle and process flow of the HTG type ceramic filter are described,as well as existing problems in the dewatering for phosphate rock slurry,and improvement measures.The production operation shows that the ceramic filter features high vacuity,low water content in the filter cake,and high yield.It is a piece of high-efficient,environmentally friendly and energy-saving solid-liquid separation equipment fit for wet milled phosphate rock powder.
01/01/2011 00:00:00
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1.6.4 Vacuum filtration
Application of the Granuflow Process to Pipeline-Transported Coal Slurry CRADA PC96-010, Final Report
In light of the current difficulties in processing fine coal and the potential for a significant increase in fines due to more demanding quality specifications, the U.S. Department of Energy's Federal Energy Technology Center (FETC) has been involved in the reconstitution of the fine clean coal resulting from advanced fine coal cleaning technologies. FETC has invented and developed a new strategy that combines fine-coal dewatering and reconstitution into one step. The process reduces the moisture content of the clean coal, and alleviates handling problems related to dustiness, stickiness, flowability, and freezing. This process has been named the GranuFlow Process. Early work successfully demonstrated the feasibility of the process for laboratory-scale vacuum filtration dewatering using asphalt emulsion. Further tests focused on the application of the process to a screen-bowl centrifuge via batch mode tests at 300 lb/hr. These tests produced roughly the same results as the laboratory filtration tests did, and they included some testing using Orimulsion, a bitumen emulsion. The Orimulsion seemed to offer greater potential for moisture reduction and was less affected by colder slurry temperatures. Most recently, FETC has conducted several series of tests in its Coal Preparation Process Research Facility. These tests dramatically showed the visible differencemore » in the dewatered product by applying the GranuFlow Process, turning it from a clumpy, wet, sticky material into a granular, dry free-flowing product. In addition, it verified previous results with improvements in moisture content, dustiness, stickiness, and freezing. Orimulsion showed a significant benefit over asphalt emulsion in moisture reduction at additions more than 5%. The overall goal of this project was to successfully apply FETC'S GranuFlow Process to improve coal slurry pipeline operations. Williams Technologies, Inc. (WTI), a leader in pipeline technology, has an interest in reducing the moisture content of the coal at the end of a coal slurry pipeline beyond what is being achieved with conventional mechanical dewatering technology. In addition, they would like to improve the handling characteristics of the dewatered coal. The GranuFlow Process has the potential of assisting in both of these areas, and its degree of applicability needed to be explored. A formal Cooperative Research and Development Agreement (CRADA) between FETC and WTI was signed in November 1996. This CRADA consisted of 6 tasks progressing from preliminary scoping tests to a commercial field test. Task 1 was completed in February 1997, and it provided sufficient information about the applicability of the GranuFlow Process to coal slurry pipelines that further testing was not needed at the present time. Thus the CRADA was terminated.« less
09/24/1997 00:00:00
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1.6.5 Vacuum filtration
Changes of some sewage sludge parameters prepared with an ultrasonic field
Studies of sewage sludge conditioning by ultrasonic field concentrate on determination of the increase of water removal effect, which depends on kind of sludge and chemical compounds used in the dewatering process. An attempt was made to find new methods of sludge preparation before dewatering. Tests presented here focused on digested and difficult dewatered sludge. The sludge was dewatered on a vacuum filter after conditioning with polyelectrolytes and the ultrasonic field. The microscopic analysis was an additional criterion to evaluate changes in the sludge structure after preparation. The polyelectrolyte dose of 3 mg/g d.m. sonicated within 15 sec. resulted in the 50% decrease of sludge volume. Results presented confirmed our previous experiences, concerning the relation between conglomerates of sludge and the effect of dewatering.
12/01/1997 00:00:00
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1.6.6 Vacuum filtration
Development of an Advanced Fine Coal Suspension Dewatering Process
With the advancement in fine coal cleaning technology, recovery of fine coal (minus 28 mesh) has become an attractive route for the U.S. coal industry. The clean coal recovered using the advanced flotation technology i.e. column flotation, contains on average 20% solids and 80% water, with an average particle size of 35 microns. Fine coal slurry is usually dewatered using a vacuum dewatering technique, providing a material with about 25 to 30 percent moisture. The process developed in this project will improve dewatering of fine (0.6mm) coal slurry to less than 20 percent moisture. Thus, thermal drying of dewatered wet coal will be eliminated. This will provide significant energy savings for the coal industry along with some environmental benefits. A 1% increase in recovery of coal and producing a filter cake material of less than 20 % moisture will amount to energy savings of 1900 trillion Btu/yr/unit. In terms of the amount of coal it will be about 0.8% of the total coal being used in the USA for electric power generation. It is difficult to dewater the fine clean coal slurry to about 20% moisture level using the conventional dewatering techniques. The finer the particle, the larger the surfacemore » area and thus, it retains large amounts of moisture on the surface. The coal industry has shown some reluctance in using the advanced coal recovery techniques, because of unavailability of an economical dewatering technique which can provide a product containing less than 20% moisture. The U.S.DOE and Industry has identified the dewatering of coal fines as a high priority problem. The goal of the proposed program is to develop and evaluate a novel two stage dewatering process developed at the University of Kentucky, which involves utilization of two forces, namely, vacuum and pressure for dewatering of fine coal slurries. It has been observed that a fine coal filter cake formed under vacuum has a porous structure with water trapped in the capillaries. When this porous cake is subjected to pressure for a short time, the free water present is released from the filter cake. Laboratory studies have shown that depending on the coal type a filter cake containing about 15% moisture could be obtained using the two-stage filtration technique. It was also noted that applying intermittent breaks in vacuum force during cake formation, which disturbed the cake structure, helped in removing moisture from the filter cakes. In this project a novel approach of cleaning coal using column flotation was also developed. With this approach the feed capacity of the column is increased significantly, and the column was also able to recover coarser size coal which usually gets lost in the process. The outcome of the research benefits the coal industry, utility industry, and indirectly the general public. The benefits can be counted in terms of clean energy, cleaner environment, and lower cost power.« less
04/30/2008 00:00:00
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1.6.7 Vacuum filtration
Dewatering Chemical-Primary Sludges
The efficiency and the cost of dewatering lime and alum generated physical-chemical treatment sludge were developed utilizing a continuous vacuum filter and a solid bowl conveyor centrifuge. Centrifugal dewatering included evaluation of both single-stage and two-stage classification dewatering. The evaluation of the data showed that lime recovery was economical with both a single and two-state centrifugal as well as vacuum filter above the plant size of 25,000,000 gal/day. Tables show the comparative cost of dewatering the lime and alum sludges for various sizes of treatment plants and with costs itemized for capital and operating considerations. Vacuum filters are the least-cost approach based on the results of the field studies. The paper also shows the process effects of varying operating parameters for these centrifuge and vacuum filter operations.
10/01/1976 00:00:00
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1.6.8 Vacuum filtration
Dewatering of drinking water treatment sludge by vacuum electro-osmosis
ABSTRACTThe objective of this research was to evaluate the dewatering of drinking water treatment sludge (DWTS) by vacuum electro-osmosis dewatering (VEOD) technology. DWTS has a high moisture content, with the water existing as free water, pore water, surface adhesion water and internal combined water. Vacuum filtration of 0.05 MPa can quickly dewater sludge and has low energy consumption, but can only remove free water and some pore water. The moisture content of the DWTS was reduced to below 79% by vacuum filtration technique alone. At this moisture content, all free water had been expelled by vacuum filtration. Electro-osmosis optimized for the experimental conditions (0.05 MPa, 2.5 V/cm) began after vacuum filtration ceased, and drew pore water and surface adhesion water to the cathode, where it was expelled through vacuum filtration. The VEOD process removed all free water. In addition, pore water and surface adhesion water were reduced by 60.2% and 15.9%, respectively.
09/01/2016 00:00:00
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1.6.9 Vacuum filtration
Effect of vacuum degree and aeration rate on sludge dewatering behavior with the aeration-vacuum method
Due to large-scale dredging operations, a large amount of sludge is inevitably produced. Large areas of land are occupied when the dredged sludge is discarded in the disposal site as waste material. The sludge dewatering with aeration-vacuum (SDAV) method is suit for treating the sludge with high water content and high clay content in the disposal site. The water in the sludge can be discharged out. The volume of the sludge can be reduced quickly, and the recycling of the land can be accelerated by this method. Most importantly, this technique is an efficient way to deal with clogging problems when pumping water from high water content, high clay content dredged sludge. Vacuum degree range tests, the aeration rate range tests, and the influencing factors of sludge dewatering behavior tests were conducted with a self-developed SDAV model test device. Sludge samples were taken from the South-to-North Water Diversion East Line Project in Huai’an White-Horse Lake disposal site, Jiangsu Province, China. The optimal range of vacuum degree and aeration rate were obtained through the test results, and the mechanisms for how the two factors work and how they affect the sludge dewatering behavior were analyzed. The suitable vacuum degree range in SDAV is below 50 kPa, and the suitable aeration rate is about 1.0 m3/h. The low-vacuum degree contributes to reduce the adsorption effect of micro-channels on soil particles in filter material and to maintain the arch structures. Aeration has the effects of expansion, disturbance, changing Reynolds number, and dynamic sieve separating. The pump quantity of water per meter of filter tube (Δm) has different change rules as the vacuum degree changes under different aeration rates. The reason is that the formed arch structures’ conformation and permeability differ greatly under different combined-conditions of vacuum degree and aeration rate. The optimal combined-condition for dewatering the sludge is 35 kPa with 1.0 m3/h.
09/01/2010 00:00:00
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1.6.10 Vacuum filtration
Enhanced ultrafine coal dewatering using flocculation filtration processes
Abstract Ultrafine coal (−150 μm) can be effectively cleaned using advanced separation techniques such as column flotation, however, dewatering it to below 20 percent moisture level using the conventional dewatering techniques is difficult. A comparative flocculation filtration study was performed for enhancing dewatering of ultrafine coal using vacuum, hyperbaric, and centrifugal filters. The cationic and anionic flocculants were added into the slurry individually or in combinations. Vacuum filtration results showed that use of flocculants increased filtration rate by several times and/or substantially reduced cake moisture. Combined use of anionic and cationic flocculants showed further improvement. Addition of flocculants significantly increased filtration rate of hyperbaric filtration and reduced cake moisture in centrifugal filtration. Anionic flocculant was more effective in enhancing fine coal dewatering than cationic flocculant in vacuum filtration while cationic flocculant was more effective in high shear centrifugal filtration. A new approach on using flocculants in vacuum filtration is proposed for enhanced fine coal dewatering.
02/01/2000 00:00:00
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1.6.11 Vacuum filtration
Feeder of vacuum energy-saving belt dewatering apparatus
The utility model relates to an energy-saving feeder of vacuum belt dewatering devices, which comprises a blanking branch pipe fed with gypsum slurry, a flow guiding barn connected with the blanking branch pipe for the inward flow of the gypsum slurry, a first-stage flow guiding plate which is arranged on the first inner wall of the flow guiding barn and is downwards inclined, a second-stage flow guiding plate which is arranged on the second inner wall below the first-stage flow guiding plate and is downwards inclined, a tiled plate which is arranged on the first inner wall below the second-stage flow guiding plate and is downwards inclined, and a perforated plate which is arranged at the spaced position between the fourth inner wall and the third inner wall at the back end of the tiled plate and is provided with a plurality of holes so as to cause the gypsum slurry to uniformly flow downwards, wherein a gap is arranged between the back end of the first-stage flow guiding plate and the second inner wall opposite to the first inner wall so as to cause the gypsum slurry to flow; a gap is arranged between the back end of the second-stage flow guiding plate and the first inner wall so as to the gypsum slurry to flow; a space is arranged between the back end of the tiled plate and the third inner wall opposite to the first inner wall below the flow guiding barn so as to cause the gypsum slurry to flow; filter cloth is used for receiving the gypsum slurry which downwards flows from the perforated plate. The utility model improves the dewatering efficiency of the vacuum belt dewatering devices.
09/20/2006 00:00:00
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1.6.12 Vacuum filtration
Real-time monitoring of the moisture content of filter cakes in vacuum filters by a novel soft sensor
Abstract The moisture content of filter cakes is probably the most important characteristic that should be kept at a desired level in industrial cake filtration applications to maintain consistent product quality and minimize energy consumption. Most of the currently applied methods for contactless real-time monitoring of the moisture content are based for example on x-ray or microwave techniques, and therefore, the equipment for the purpose is highly specialized. This paper introduces a novel soft sensor for filter cake moisture estimation that uses machine learning algorithms and data collected with basic process instrumentation. The method is primarily based on the cooling effect observed in the cake and air, caused by evaporation of liquid from the cake during the dewatering period, and it can be supported by other process data. The specific energy consumption of vacuum filtration and the subsequent thermal drying to zero moisture is also analyzed. The results of pilot-scale experiments with calcite slurry and a horizontal belt vacuum filter show that in order to minimize the specific energy consumption of vacuum filtration, it is crucial to find the right combination of slurry concentration, vacuum level, and mass of filter cake per unit area. The proposed method for estimating the filter cake moisture content is especially suitable for real-time monitoring and control, enabling also considerable reduction in the energy consumption of the overall process. When applying the proposed soft sensor method in a pilot-scale process, the mean absolute error of the estimated moisture content of the filter cake is ∼0.4 percentage points when the temperature of air at the vacuum pump inlet and the vacuum pump air flow rate are included in the input variables.
03/01/2019 00:00:00
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1.6.13 Vacuum filtration
Test Study on Dewatering Effect of Sewage Sludge by Vacuum Method
The aeration-vacuum dewatering method is a new kind of solid-liquid separate technique. The filter clogging problem in the routine vacuum dewatering procedure of sludge can be solved by the method. This method is used to dewater the sewage sludge in this paper. Through the dewatering model test of the sewage sludge with this method, the change law of the solid content and the volume of the sewage sludge are studied. The dewatering effect of sewage sludge is got further more. The test results indicate that there is a great promotion for improving the solid content and reducing the volume by using the aeration-vacuum method.
01/01/2012 00:00:00
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1.6.14 Vacuum filtration
Vacuum slurry dewatering machine
The invention provides a vacuum slurry dewatering machine. The vacuum slurry dewatering machine comprises a frame, a slurry storage tank, a main control integrated system, a vacuum filtration system and a scraping device, wherein the vacuum filtration system comprises a vacuum device, a distributing valve, a rotating roller, and a plurality of filtering suction disks alternately arranged on the rotating roller; one part of each filtering suction disk is positioned inside the slurry storage tank, and one part of each filtering suction disk is located above the slurry storage tank; the scraping device is located on the surface of the filtering suction disks; the vacuum device communicates with each filtering suction disk through the distributing valve; and each filtering suction disk is composed of a plurality of molecular film filtration plates. The vacuum slurry dewatering machine provided by the invention has the advantages of full automation, no addition of chemicals, high dewatering efficiency, low energy consumption, clear filtrate, small occupied land area, etc.
05/31/2017 00:00:00
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1.6.15 Vacuum filtration
Alternative additives to enhance slurry dewatering

1. A method comprising:adding a wash fluid to an alumina trihydrate bearing slurry comprising alumina trihydrate and caustic-soluble aluminate liquor;adding to the alumina trihydrate bearing slurry or to the wash fluid a composition comprising at least one R-succinic compound having a structure selected from formula (I) or formula (II), a conjugate acid-base of the R-succinic compound having a structure selected from formula (I) or formula (II), and combinations thereof; wherein formula (I) is and formula (II) is andwherein R and R′ are independent, distinct, and represent alkyl, alkenyl, or aromatic hydrocarbon groups containing 1-30 carbon atoms. 2. The method of claim 1, wherein the R-succinic compound is selected from octadecenyl succinic acid, hexadecenyl succinic acid, dodecenyl succinic acid, or any combination thereof. 3. The method of claim 1 wherein the composition further comprises a base. 4. The method of claim 1, further comprising in order:preparing an aqueous slurry of pulverized bauxite ore and caustic solution;digesting, comprising extracting alumina from the bauxite ore as a caustic-soluble aluminate liquor;clarifying, comprising removing solid particles from the liquor;precipitating, comprising forming the alumina trihydrate bearing slurry from the liquor, andclassifying, comprising separating alumina trihydrate seeds from the liquor. 5. The method of claim 1, further comprising:removing liquor and water from the alumina trihydrate bearing slurry to give alumina trihydrate. 6. The method of claim 5, further comprising calcining the alumina trihydrate. 7. The method of claim 1, wherein the R-succinic compound forms in situ within the alumina trihydrate bearing slurry or the wash fluid by opening the ring of an R-succinic anhydride compound. 8. The method of claim 7 in which the R-succinic compound forms from an anhydride added to the alumina trihydrate bearing slurry or the wash fluid. 9. The method of claim 1, wherein the wash fluid comprises water. 10. The method of claim 1, wherein the wash fluid consists essentially of water. 11. The method of claim 1, wherein the composition is added to the slurry alongside the wash fluid, before the wash fluid, after the wash fluid, or combinations thereof. 12. The method of claim 1, wherein the composition is added to the wash fluid. 13. The method of claim 5, wherein the removing liquor and water from the alumina trihydrate bearing slurry comprises filtration. 14. The method of claim 5, wherein the wash fluid is added to the slurry before the removing, during the removing, after the removing, or combinations thereof. 15. The method of claim 5, wherein the removing liquor and water from the alumina trihydrate bearing slurry comprises gravity separation, pressure separation, vacuum separation, or combinations thereof.
02/26/2014 00:00:00
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1.6.16 Vacuum filtration
Dewatering machine and process

1. A dewatering machine for reducing moisture of at least one of a polymer and an elastomer, said machine comprising:a generally solid barrel, said barrel being formed with an opening for receiving a feed of said at least one of said polymer and said elastomer in said machine;a pair of counter-rotating screws disposed in said barrel, at least a portion of said screws being intermeshing, and wherein said screws include a geometry that is closed axially and cross-channel;drive means coupled to said screws to cause the screws to rotate, whereby said screws transfer energy to said at least one of said polymer and said elastomer to fuse particles of the at least one of the polymer and the elastomer together; andat least one mechanical filter connected to said barrel to remove moisture from said at least one of said polymer and said elastomer after said particles have been fused,whereby an amount of fines escaping the machine is reduced, and said moisture of the at least one polymer is reduced from up to 40 percent water by weight to less than 0.5 percent water by weight and of the at least one elastomer is reduced from up to 50 percent water by weight to less than 3.0 percent water by weight. 2. The dewatering machine of claim 1,further comprising a second opening formed in said barrel for receiving an additive material; andmeans for introducing steam into said barrel downstream of said second opening. 3. The dewatering machine of claim 2, further comprising a restriction in said barrel downstream of said second opening, wherein said restriction holds pressure in the barrel. 4. The dewatering machine of claim 1, further comprising a vacuum filter connected to said barrel downstream of said at least one mechanical filter. 5. The dewatering machine of claim 1, wherein said said screws are formed with a non-intermeshing portion. 6. The dewatering machine of claim 5, wherein a ratio of a bore diameter of said barrel to a distance extending from an inner wall of said barrel to a centerline of said screws is from about 1.4 to about 1.78. 7. The dewatering machine of claim 1, further comprising a wedgebar drain. 8. The dewatering machine of claim 1, further comprising means connected to said barrel for direct contact heating of said machine. 9. The dewatering machine of claim 1, further comprising means connected to said barrel for direct contact cooling of said machine. 10. The dewatering machine of claim 1, wherein said at least one of said polymer and said elastomer is selected from the group consisting of acrylonitrile butadiene styrene, styrene acrilo nitrile, butadiene rubber, nitrile rubber, isoprene rubber, butyl or isobutylene-isoprene rubber, chloroprene rubber, acrylate rubbers, styrene butadiene rubber, styrene butadiene styrene rubber, styrene isoprene styrene, ethylene propylene rubber, epichlorohydrin rubber, synthetic rubber, thermoplastic elastomer, thermoplastic rubber, and biomass materials. 11. A method of dewatering for reducing moisture of at least one of a polymer and an elastomer, said method comprising the steps of:providing a dewatering machine including a generally solid barrel;disposing a pair of counter- rotating screws in said barrel, at least a portion of said screws being intermeshing, and wherein the screws include a geometry that is closed axially and cross-channel;rotating said screws with drive means;feeding said at least one of said polymer and said elastomer into an opening formed in said barrel and into said screws;fusing particles of said at least one of said polymer and said elastomer together to reduce an amount of fines escaping said machine by transferring energy from said screw rotation to the at least one of said polymer and said elastomer;after said particles have been fused, removing moisture from said at least one of said polymer and said elastomer with at least one mechanical filter connected to said barrel; andreducing said moisture of said at least one polymer from up to 40 percent water by weight to less than 0.5 percent water by weight and of said at least one elastomer from up to 50 percent water by weight to less than 3.0 percent water by weight. 12. The method of dewatering of claim 11, further comprising the steps of:feeding an additive material into a a second opening formed in said barrel; andintroducing steam into said barrel downstream of said second opening. 13. The method of dewatering of claim 11, further comprising the step of retaining pressure in said barrel with a restriction in the barrel downstream of said second opening. 14. The method of dewatering of claim 11, further comprising the step of drawing a vacuum in said barrel with a vacuum filter connected to the barrel downstream of said at least one mechanical filter. 15. The method of dewatering of claim 11, wherein said step of fusing particles of said at least one of said polymer and said elastomer includes forming said screws with a non-intermeshing portion. 16. The method of dewatering of claim 11, wherein the step of fusing particles of said at least one of said polymer and said elastomer further comprises the steps of heating the at least one of the polymer and the elastomer to a range of from about 132 degrees Celsius to about 157 degrees Celsius, and maintaining a pressure in said barrel of from at least about 44 pounds per square inch of atmosphere. 17. The method of dewatering of claim 11, further comprising the step of draining free water from said barrel with a wedgebar drain in a feed section of the barrel. 18. The method of dewatering of claim 11, further comprising the step of heating said machine with steam injection. 19. The method of dewatering of claim 11, further comprising the step of cooling said machine with an introduction of tempered water. 20. The method of dewatering of claim 11, wherein said at least one of said polymer and said elastomer is selected from the group consisting of acrylonitrile butadiene styrene, styrene acrilo nitrile, butadiene rubber, nitrile rubber, isoprene rubber, butyl or isobutylene-isoprene rubber, chloroprene rubber, acrylate rubbers, styrene butadiene rubber, styrene butadiene styrene rubber, styrene isoprene styrene, ethylene propylene rubber, epichlorohydrin rubber, synthetic rubber, thermoplastic elastomer, thermoplastic rubber, and biomass materials.
05/14/2012 00:00:00
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1.6.17 Vacuum filtration
Method and apparatus for dewatering
While the present invention has been described in connection with the preferred embodiments of the various figures, it is to be understood that other similar embodiments may be used or modifications and additions may be made to the described embodiment for performing the same function of the present invention without deviating therefrom. Therefore, the present invention should not be limited to any single embodiment, but rather construed in breadth and scope in accordance with the recitation of the appended claims.
1. A method of treating clay contaminated ultra fine coal particles, said method including the steps of: forming an aqueous slurry of clay contaminated ultra fine coal particles; imparting high shear forces to the slurry containing the clay contaminated ultra-fine coal particles to strip clay contaminants from the surfaces of the coal particles and to subdivide the size of the clay contaminant to clay platelets without flocculating the ultrafine coal particles; adding a sufficient amount of a peptizing agent to said slurry thereby peptizing the clay platelets to impart a state of discreetness in the aqueous slurry; subjecting said peptized aqueous slurry to a size separator selected from the group consisting of a sieve having a barrier layer of aqueous permeable unflocculated dilatent coal thereon, and a filter having a barrier layer of aqueous permeable unflocculated dilatent coal thereon, thereby forming a mass of dilatent coal particles; using the dilatancy of said dilatant coal mass in combination with an applied force for dewatering the coal mass by draining aqueous medium along with discrete peptized clay platelets form the coal mass; and recovering the coal mass. 2. The method according to claim 1 wherein said step of using the dilatancy of the dilatant coal mass includes treating the coal mass with an air flow for said dewatering. 3. The method according to claim 1 wherein said step of using the dilatancy of the dilatant coal mass includes treating the coal mass with mechanical energy for said dewatering. 4. The method according to claim 1 wherein said size separator comprises a filter and said filter is a vacuum filter. 5. The method according to claim 4 wherein said step of using the dilatancy includes drawing quantities of atmospheric air through the dilatant coal mass into said vacuum filter. 6. The method according to claim 1 wherein said peptizing agent comprises a sufficient amount of sodium hexametaphosphate to act as a peptizing agent. 7. The method according to claim 1 wherein said step of using the dilatancy includes treating said dilatant coal mass in a dewatering chamber. 8. The method according to claim 1 including the further step of: mixing lignosulfonate with the coal mass derived from said step of recovering; and forming an agglomerated extruded mass of coal particles after a mixture of said lignosulfonate. 9. The method according to claim 1 wherein said step of using the dilatency of the dilatent coal mass includes exposing the dilatant coal mass to an open atmosphere.
07/24/1991 00:00:00
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1.6.18 Vacuum filtration
Methods of enhancing fine particle dewatering

1. A process for dewatering a slurry of hydrophobic coal particulate material comprising:i) forming a layer of hydrophobes on the surface of said hydrophobic coal particulate material and initially increasing the hydrophobicity of said hydrophobic coal particulate material by adding hydrocarbon oil to said slurry, wherein the hydrophobicity of said coal particulate material is increased;ii) adding a nonionic surfactant of hydrophile-lipophile balance (HLB) number less than 15 dissolved in at least one organic solvent;iii) allowing said nonionic surfactant to adsorb on less hydrophobic parts of the surface of said hydrophobic coal particulate material to further increase hydrophobicity of said hydrophobic coal particulate material having increased hydrophobicity from the addition of said hydrocarbon oil; andiv) effecting separation of water from said slurry of hydrophobic coal particulate material by subjecting said slurry to a mechanical method of dewatering. 2. The process of claim 1, further comprising agitating said slurry. 3. The process of claim 1, wherein said particulate material comprises particles of less than 2 mm in size. 4. The process of claim 1, wherein said nonionic surfactant is selected from the group consisting of: fatty acids, fatty esters, phosphate esters, hydrophobic polymers, ethers, glycol derivatives, sarcosine derivatives, silicon-based surfactants and polymers, sorbitan derivatives, sucrose and glucose esters and derivatives, lanolin-based derivatives, glycerol esters, ethoylated fatty esters, ethoxylated amines and amides, ethoxylated linear alcohols, ethoxylated tryglycerides, ethoylated vegetable oils, and ethoxylated fatty acids. 5. The process of claim 1, wherein said nonionic surfactant is dissolved in an oil of vegetable origin. 6. The process of claim 1, wherein said organic solvent includes a solvent selected from the group consisting of: light hydrocarbon oils and short-chain alcohols. 7. The process of claim 6, wherein said light hydrocarbon oils are selected from diesel oil, kerosene, gasoline, petroleum distillate, turpentine, naphtanic oils, and oils of vegetable origins. 8. The process of claim 6, wherein said short-chain alcohols have carbon atom numbers less than eight. 9. The process of claim 1, wherein said mechanical method of dewatering is selected from the group consisting of: vacuum filtration, pressure filtration, centrifugal filtration, and centrifugation. 10. A process for dewatering a slurry of hydrophobic coal particulate material comprising:forming a layer of hydrophobes on the surface of said hydrophobic coal particulate material and initially increasing the hydrophobicity of said hydrophobic coal particulate material by adding hydrocarbon oil to said slurry, wherein said hydrophobic coal particulate material exhibits a contact angle and the contact angle of said hydrophobic coal particulate material is below 45°;dissolving a nonionic surfactant of hydrophile-lipophile balance (HLB) number less than 15 in at least one organic solvent;adding said dissolved nonionic surfactant and said at least one organic solvent to said slurry; andallowing said nonionic surfactant to adsorb on less hydrophobic parts of the surface of said hydrophobic coal particulate material, to further increase the hydrophobicity of said material having increased hydrophobicity from the addition of said hydrocarbon oil, wherein said contact angle of said hydrophobic coal particulate material is above 45°; andeffecting separation of water from said slurry of hydrophobic coal particulate material by subjecting said slurry to a mechanical method of dewatering. 11. The process according to claim 10, further comprising agitating said slurry. 12. The process of claim 10, wherein said organic solvent includes a solvent selected from the group consisting of: light hydrocarbon oils and short-chain alcohols. 13. The process of claim 12, wherein said light hydrocarbon oils are selected from diesel oil, kerosene, gasoline, petroleum distillate, turpentine, naphtanic oils, and oils of vegetable origins. 14. The process of claim 12, wherein said short-chain alcohols have carbon atom numbers less than eight. 15. The process of claim 10, wherein said coal particulate material comprises particles of less than 2 mm in size. 16. A process for dewatering a slurry of superficially oxidized coal particles, comprising:i) initially regenerating the hydrophobic surface of said oxidized coal particles,ii) forming a layer of hydrophobes on the surface of said hydrophobic coal particulate material and increasing the hydrophobicity of said coal particles by adding hydrocarbon oil to said slurry,ii) adding a non-ionic surfactant of hydrophile-lipophile balance (HLB) number less than 15 dissolved in at least on organic solvent;iii) allowing said non-ionic surfactant to adsorb on less hydrophobic parts of the surface of said coal particles, to further increase the hydrophobicity of said coal particles having increased hydrophobicity from the addition of said hydrocarbon oil; andiv) effecting separation of water from said slurry of hydrophobic particulate material by subjecting said slurry to a mechanical method of dewatering. 17. The process of claim 16, wherein said superficially oxidized coal particles are wet ground in a ball mill to regenerate the hydrophobic surface.
08/03/2007 00:00:00
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1.7 Screw press

0

A dewatering screw press is a screw press that separates liquids from solids. It is a simple, slow moving device that accomplishes dewatering by continuous gravitational drainage. Screw presses are often used for materials that are difficult to press, for example those that tend to pack together. The screw press squeezes the material against a screen or filter and the liquid is collected through the screen for collection and use. [\[link\]](https://en.wikipedia.org/wiki/Dewatering_screw_press) **Highlights:** * The objective of the work presented is to develop a mechanically based pretreatment process for biomass using a screw press. The **screw press** used for this purpose is an oil press which is known to provide continuous high shear and pressure forces. The results obtained in this study show the feasibility and potential for **degradation of the lignocellulosic structure** as well as dewatering of biomass in the screw press.[ \[Art. #ARTNUM\]](#article-96317-2303649050) * The excess sewage sludge was aerobically stabilized and dewatered with a screw press. \[...\] Measurement factors for electric energy consumption for mechanically dewatered sewage sludge were determined, which ranged between **0.94 and 1.5 kWhm −3 with the average value at 1.17 kWhm −3 .** The shares of devices used for sludge dewatering and aerobic stabilization in the total energy consumption of the plant were also established, which were 3% and 25% respectively.[ \[Art. #ARTNUM\]](#article-96317-2559813780) * A process for dewatering a slurry comprising a **microfibrillated cellulose** by only subjecting the slurry to a mechanical pressure, without significant hornification of the microfibrillated cellulose \[...\] The process according to claim 1 , wherein the slurry is subjected to the second mechanical pressure by conducting the slurry to a screw press. \[...\] The process according to claim 1 , wherein the **dry content** of the dewatered slurry comprising a microfibrillated cellulose is **1-50% by weight**.[ \[Art. #ARTNUM\]](#article-96317-US10240289B2) * Patent Stora Enso * Patent also claimed for centrifugation * Andritz rebuilt sludge screw press for Stora Enso [\[web\]](https://bioenergyinternational.com/technology-suppliers/andritz-completes-sludge-screw-press-rebuild-stora-enso-anjala) * A process for dewatering a starting biomass material comprising a **pectin** and water \[...\] wherein the step of mechanically separating at least a portion of the water from the wetted biomass material comprises pressing the wetted biomass with a screw press \[...\] The dewatered biomass material comprises dry matter in an amount from about **35 to about 60%** by weight of the dewatered biomass material.[ \[Art. #ARTNUM\]](#article-96317-US8764991B2) * Patent CP Kelco ApS * To provide a **screw type dewatering apparatus** which shakes swing rings well to improve dewatering efficiency, and in which a swing ring driving means is hardly worn out so that life of the swing ring driving means is substantially extended.[ \[Art. #ARTNUM\] ](#article-96317-2821689307) * Patent Hongwoo * A process for making a **dehydrated fruit pulp slurry** \[...\] producing a dehydrated fruit pulp slurry with a **moisture content of less than 10 wt%** of the dehydrated fruit pulp slurry, and comprising a dewatering step comprising mechanical dewatering, chemical dewatering and/or enzymatic dewatering, and further comprising a drying step \[...\] the mechanical dewatering comprises using a screw presser [\[Art. #ARTNUM\]](#article-96317-EP2584924B1) * Patent Coca Cola Company **Combinations:** * A dewatering screw press \[...\] Dewatering efficiency is improved by **vibrations** that are strong near the middle of the **screen**[ \[Art. #ARTNUM\]](#article-96317-2966885010) * Patent V.Y.F. EXPRESS INC. * For manure **Combined with treatment:** * The sludge dewatering performance of screw press dehydrator was investigated.The results show that for the digested sludge with moisture content of 97.9%, under the condition of flocculant dosing rate of 0.51% and screw speed of 0.25 r/min, the minimum **cake moisture content after dewatering is 70.3%, the solid recovery is 98.89%** and the sludge treatment capacity is 24.84 kg/h. For the excess sludge with moisture content of 99.7%, under the condition of **flocculant** dosage rate of 0.94% and screw speed of 0.75 r/min, the cake moisture content after dewatering is 82.5%, the solid recovery is 92.46%, and the sludge treatment capacity is 8.64 kg/h.[ \[Art. #ARTNUM\]](#article-96317-2378189068) * **Biomass from high nature value grasslands** is a potential resource for renewable energy production, since its use as forage is declining due to decreasing livestock levels in many European regions. This study investigated silages and the derived press cakes after **hydrothermal conditioning** and mechanical dewatering from 18 European grassland sites on fuel relevant parameters.[ \[Art. #ARTNUM\]](#article-96317-1984659468) * Tropical biomass feedstock candidates, banagrass ( Pennisetum purpureum  ×  Pennisetum glaucum ), guinea grass ( Panicum maximum ), energy cane ( Saccharum spontaneum ), and sugar cane ( Saccharum officinarum L.) (as reference) were harvested and processed using pressing and leaching techniques to improve fuel properties for thermochemical conversion. \[...\] At least 20% of the initial fuel dry matter was partitioned to the byproduct liquid streams as total solids under the combined influences of **leaching and mechanical processing.**[ \[Art. #ARTNUM\]](#article-96317-1179553882) * Screw press of [Vincent Corporation](https://vincentcorp.com/content/new-cp-4-press) (see also Suppliers list)

1.7.1 Screw press
A laboratory sludge press for characterizing sludge dewatering
A laboratory scale sludge press is described. Its use in measuring the specific filtration resistance of a slurry is outlined. The effects of applied pressure and press time on filtrate flow rate and sludge cake solids are discussed as are the effects of various combinations of primary and secondary sludge. Its use in optimizing the polymer formulation for improved dewaterability of sludge in a screw press is detailed. Comparisons of laboratory sludge press predictions and the results of mill scale screw press and belt filter trials are presented.
02/01/1997 00:00:00
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1.7.2 Screw press
Changes in Settling Characteristics and Fate of Solids in Dairy Manure Using Anaerobic Digestion, Mechanical Liquid-Solid Separation, and Electrocoagulation
Manure from an 1,100 dairy in Weber County, Utah was treated first through anaerobic digestion in an Induced Blanket Reactor (IBR). Then the effluent passed through either a screw press separator or a two-stage dewaterer, to remove additional solids. On a laboratory scale, samples were also treated with an electrocoagulation (EC) unit to evaluate the potential for its use in a farm setting. Manure was taken between each unit operation and placed into a settling column seven feet high and twelve inches in diameter. Samples were taken from the column at time 0, 0.5, 1, 2, 4,8, 12, and 24 hours at depths 0, 1, 3, 5, and 6 ft (One foot of headspace was left in the top of the column to allow for mixing at time=0). Total solids (TS), volatile solids (VS), suspended solids (SS), and total suspended volatile solids (SVS) were determined for each depth at each time interval. Solids in the influent manure did not settle. Anaerobic stabilization removed 36% and 44% of the TS and VS respectively. The screw press removed 6% of the remaining TS. Use of a two-stage dewaterer was more effective, removing 38% of the TS. Two levels of EC treatment resulted in 78% and 89% removal of TS and VS respectively for the lower treatment, and 85% and 94% of the TS and VS respectively for the higher treatment level. The treatment system removed 87-91% of the TS and 95-97% of the VS depending on the level of treatment by electrocoagulation.
01/01/2006 00:00:00
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1.7.3 Screw press
Continuous expression of slurry in a screw press
An approximate method is described for predicting the steadystate performance of a screw press for the continuous expression of a slurry, with the worm channel being modified as the path between two flat plates. Screw expression of a slurry involves two mechanisms of dewatering which, for a batch operation, can be analyzed by the variable-pressure, variable-rate theory of filtration and by consolidation theory. By assuming that the expression consists of a succession of batch processes, basic equations are derived for the relationship between the dehydration rate, the feed rate, and the expression pressure distribution in a constant-pitch, straighttaper screw press. The thickness of the filter cake in the worm channel and the flow distribution in the consolidated cake are calculated for a given pressure distribution and feed rate, and the solids concentration and rate of discharge of the cake are estimated. The critical speed of rotation of the worm, at which the slurry becomes highly deliquored, is strongly influenced by the external diameter and helical angle of the worm. The theoretical results are in good agreement with experimental data for clay slurries with a concentration of 0.31-0.46 in the feed.
01/01/1985 00:00:00
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1.7.4 Screw press
Dewatering saturated, networked suspensions with a screw press
A model is presented for the dewatering of a saturated two-phase medium in a screw press. The model accounts for the detailed two-phase rheological behaviour of the pressed material and splits the press into two zones, an initial well-mixed constant-pressure region followed by an axial transport region in which the total pressure steadily increases. In this latter region, a slowly varying helical coordinate transformation is introduced to help reduce the dynamics to an annular bi-axial compression of the two-phase medium. Unlike previous modelling, the transition point between the two zones is determined self-consistently, rather than set a priori, and the pressure along the length of the press is deduced from the rheology of the two-phase flow rather than averaging the two-phase dynamics over a cross section of the press. The model is compared to experimental observations of the dewatering of a paper-making fibre suspension and of a clay slurry, and is shown to reproduce operational data.
12/12/2019 00:00:00
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1.7.5 Screw press
Effects of hydrothermal conditioning and mechanical dewatering on ash melting behaviour of solid fuel produced from European semi-natural grasslands
Abstract Biomass from high nature value grasslands is a potential resource for renewable energy production, since its use as forage is declining due to decreasing livestock levels in many European regions. This study investigated silages and the derived press cakes after hydrothermal conditioning and mechanical dewatering from 18 European grassland sites on fuel relevant parameters. Through silage treatment high reductions of the concentration in the fuel of more than 73% of Cl, K and Na were obtained. Experimental investigation of the ash melting behaviour showed an increase of the ash softening temperature (AST) from approximately 1000 °C for the ash from the silage to 1050 °C for the press cake ashes. At the spherical, hemisphere and flow temperature differences between silage and press cake ashes were even bigger and ranged from 63 to 67 K. Linear regression models, which were based on the fuel content of K, Ca, Si, Al and Na, were able to predict the AST with high accuracy ( R 2  = 0.88–0.89). Models showed that an increasing content of K led to decreasing AST. By contrast, AST was positively influenced by increasing contents of Ca. The effect of Si depended on the content of alkalis and earth alkalis.
02/01/2014 00:00:00
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1.7.6 Screw press
Enhancing the dewaterability of anaerobically digested sludge using fibrous materials recovered from primary sludge: demonstration from a field study
Sludge dewatering is an important process for determining the operation cost of sludge disposal. Hence, improving the dewaterability of anaerobically digested sludge containing high water content is of paramount significance. For this challenge, we developed a novel process in which fibrous materials initially collected from a primary sedimentation tank, namely recovered fibers, were used as an auxiliary agent to improve the dewaterability of anaerobically digested sludge. The objective of this study was to investigate the feasibility of using the developed process to improve sludge dewaterability. Three fibrous materials individually recovered from the respective primary sedimentation tanks in different wastewater treatment plants (WWTPs) were used to investigate sludge dewaterability, organic C compositions, and calorific values. The recovered fibers showed comparable compositions irrespective of the WWTP. Six different WWTP sludge samples after anaerobic digestion were continuously supplied to three different dewatering devices, i.e., screw press, centrifuge, and belt press machines, with or without the supply of recovered fibers. Irrespective of the type of a dewatering device, the supply of recovered fibers mixed with the tested sludge samples at a feed ratio of 0.18–0.20 g-fibers/g-sludge (dry weight) reduced the amount of polymer flocculant by 13–50%, thereby displaying the superiority of the addition of recovered fibers. Furthermore, at fiber feed ratios of 0.20 g-fibers/g-sludge and 0.40 g-fibers/g-sludge when the rates of sludge supply and polymer flocculant were kept constant, the corresponding water contents in the dewatered sludge cakes decreased to about 74–76% and 69–72%, respectively. The consistent results regardless of the dewatering device or sludge sample showed the significance of the addition of recovered fibers for improvement in sludge dewaterability.
04/24/2019 00:00:00
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1.7.7 Screw press
Evaluation of energy consumption during aerobic sewage sludge treatment in dairy wastewater treatment plant
Abstract The subject of the research conducted in an operating dairy wastewater treatment plant (WWTP) was to examine electric energy consumption during sewage sludge treatment. The excess sewage sludge was aerobically stabilized and dewatered with a screw press. Organic matter varied from 48% to 56% in sludge after stabilization and dewatering. It proves that sludge was properly stabilized and it was possible to apply it as a fertilizer. Measurement factors for electric energy consumption for mechanically dewatered sewage sludge were determined, which ranged between 0.94 and 1.5 kWhm −3 with the average value at 1.17 kWhm −3 . The shares of devices used for sludge dewatering and aerobic stabilization in the total energy consumption of the plant were also established, which were 3% and 25% respectively. A model of energy consumption during sewage sludge treatment was estimated according to experimental data. Two models were applied: linear regression for dewatering process and segmented linear regression for aerobic stabilization. The segmented linear regression model was also applied to total energy consumption during sewage sludge treatment in the examined dairy WWTP. The research constitutes an introduction for further studies on defining a mathematical model used to optimize electric energy consumption by dairy WWTPs.
02/01/2017 00:00:00
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1.7.8 Screw press
Experimental Research on Sludge Dewatering by Screw Press Dehydrator
The sludge dewatering performance of screw press dehydrator was investigated.The results show that for the digested sludge with moisture content of 97.9%,under the condition of flocculant dosing rate of 0.51% and screw speed of 0.25 r/min,the minimum cake moisture content after dewatering is 70.3%,the solid recovery is 98.89% and the sludge treatment capacity is 24.84 kg/h.For the excess sludge with moisture content of 99.7%,under the condition of flocculant dosage rate of 0.94% and screw speed of 0.75 r/min,the cake moisture content after dewatering is 82.5%,the solid recovery is 92.46%,and the sludge treatment capacity is 8.64 kg/h.Compared with belt dehydrator,the sludge treatment effect is greatly improved.
01/01/2009 00:00:00
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1.7.9 Screw press
Experiments for Designing a Screen of a Screw Press for Dewatering of Cattle Dung Slurry
Dewatering of digested cattle dung slurry from a biogas plant is important in today's context as it offers conservation of important resource like water and also makes it possible to produce either compost or solid fuel. Recently, screw presses have found application for digested slurry dewatering in western countries. In order to develop an indigenous design of a screw press, some experiments were performed to assess the behavior of slurry under pressure and to find the particle size distribution. The data would essentially help in designing the screen of the screw press.
01/01/2011 00:00:00
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1.7.10 Screw press
Green processing of tropical banagrass into biofuel and biobased products: an innovative biorefinery approach.
Abstract Banagrass ( Pennisetum purpureum ) approximately 4 months old was hand-harvested and shredded. Half of the sample was dewatered using a screw-press, whereby the extracted juice was used for cultivating an edible fungus, Rhizopus microsporus , for aquaculture feed supplementation. The remaining biomass was divided into four separate streams: (1) wet, juiced; (2) dry, juiced; (3) wet, unjuiced; and (4) dry, unjuiced. Each stream was pretreated with dilute sulfuric acid and compared on the basis of sugar release at varying acid concentrations, temperatures, and residence times. Wet, juiced banagrass released the most soluble sugars (theoretical xylose and ∼85% glucose). Ultrasonication (20 kHz) was applied to further increase monomeric sugar release but demonstrated little improvement on total sugar yields. Fungal biomass generated from banagrass juice exhibited potential as a fungal-protein production medium producing 1.16 ± 0.34 g biomass increase/g initial biomass.
01/01/2011 00:00:00
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1.7.11 Screw press
HIGH EFFICIENCY DEWATERING DECANTER CENTRIFUGE TO IMPROVE DEWATERABLITY
According to a high-efficiency centrifugal dehydrator for improving dewaterability of the present invention, a single ring-shaped blocking plate is disposed between a sludge discharge port of a screw conveyor in a centrifugal dehydrator drum and a cake discharge port of the drum so that a dehydration area in the drum can be narrowed, the pressure of the screw conveyor is maximized, and dehydration efficiency can be increased. Also, the conical angle of the drum having a conical shape is adjusted to be increased so that the dehydration area is narrowed and a filtering area is lengthened, the dehydration effect is increased by raising the pressure received by the dehydration area, a filtrate treatment performance is improved, and a sludge treatment amount is increased. The ring-shaped blocking plate that is applied to the present invention is made of stainless steel, and maximizes the dehydration effect by separating a solid material from filtrate, narrowing the dehydration area, and receiving a higher pressure. The outer diameter of the blocking plate is changed by the volume ratio of the concentration of the sludge to be treated and can vary by centrifugal dehydrator model. Also, an additional suspension separation means is configured to be in the drum according to the present invention.
08/01/2014 00:00:00
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1.7.12 Screw press
Manure screw press having screen vibration
A dewatering screw press has a hopper, a discharge outlet, a cylindrical screen flexibly mounted to the hopper and rigidly connected to the discharge outlet, a screw mounted to rotate beginning in the hopper and ending at the discharge outlet, the screw having an outer surface contacting the cylindrical screen, and at least one vibrator mounted to the cylindrical screen. Dewatering efficiency is improved by vibrations that are strong near the middle of the screen, while reducing or eliminating vibration near the discharge end of the screen where pressure is highest and a breaking of the seal between the screw and the screen due to vibration can reduce dewatering of sludge near the discharge end of the screen.
07/09/2019 00:00:00
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1.7.13 Screw press
Mechanical dewatering and water leaching pretreatment of fresh banagrass, guinea grass, energy cane, and sugar cane: Characterization of fuel properties and byproduct streams
Abstract Tropical biomass feedstock candidates, banagrass ( Pennisetum purpureum  ×  Pennisetum glaucum ), guinea grass ( Panicum maximum ), energy cane ( Saccharum spontaneum ), and sugar cane ( Saccharum officinarum L.) (as reference) were harvested and processed using pressing and leaching techniques to improve fuel properties for thermochemical conversion. Test results are reported that summarize the impacts of treatment methods on fuel properties and provide detailed data on mass and element partitioning between process streams to inform system design. The processed fuels had lower ash contents, improved heating values, higher ash deformation temperatures, and higher volatile matter to fixed carbon ratios than the parent materials. The liquid streams generated by the process were characterized for chemical oxygen demand, sugar content, total solids, total suspended solids, and major and trace elements. At least 20% of the initial fuel dry matter was partitioned to the byproduct liquid streams as total solids under the combined influences of leaching and mechanical processing. Analytical results support the land application of liquids as a nutrient recycling option. Element partitioning between solid and liquid process streams was determined and material and element mass balances were performed. Chemical equilibrium calculations based on the elemental composition of the parent materials and processed fuels and steam gasification conditions predicted substantial reductions in concentrations of K, Cl, S, Na, and Mg in the product gas.
11/01/2015 00:00:00
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1.7.14 Screw press
Mechanical Pretreatment of Lignocellulosic Biomass Using a Screw Press as an Essential Step in the Biofuel Production
Since mechanical pretreatment makes lignocellulosic biomass accessible to any further solution and (bio-)chemical modification processes, it is a step which is essential for the entire downstream processing. The objective of the work presented is to develop a mechanically based pretreatment process for biomass using a screw press. The screw press used for this purpose is an oil press which is known to provide continuous high shear and pressure forces. The results obtained in this study show the feasibility and potential for degradation of the lignocellulosic structure as well as dewatering of biomass in the screw press. Adsorption and extraction studies indicate that the products from the screw press have a larger specific surface area and more disruption of cell structure than those treated only with a cutting mill. Furthermore, it is found that the process with a screw press requires considerably less energy in comparison to the conventional thermal-mechanical process.
09/20/2012 00:00:00
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1.7.15 Screw press
METHOD FOR THE PRODUCTION OF A PLANT GROWTH SUBSTRATE FROM CROP RESIDUES
The method relates to the manufacture of a plant growth substrate from maize straw. It is robust, suitable for large scale implementation and comprises the following steps: (i) Collection of the straw from the field (ii) Storage of the straw in heaps (iii) Mechanical dewatering of the straw (iv) Disintegration of the straw structure using impact crushing (v) Fermentation The steps iii, iv, and v can be executed in any possible order. The resulting plant growth substrate is characterized by its dry matter content of around 50%, its density of around 200 kg/m3, its total pore volume of >80%, its water content at field capacity of >40%, its carbon to nitrogen ratio of around 60, and its electrical conductivity <1mS/cm. The plant growth substrate is structurally stable and suitable to apply alone or in blends with peat, compost or other materials, for propagation of seeds and young plants, as well as for horticultural production, production of ornamental plants, landscaping and hobby gardening. Its specifications make it a viable substitute of peat.
07/13/2017 00:00:00
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1.7.16 Screw press
OPERATION CONTROL METHOD FOR MULTIPLE SCREW PRESS
PROBLEM TO BE SOLVED: To provide a control method by which multiple screw press operation is performed while controlling the feed pressure and feed flow rate of sludge to be fed to the multiple screw press constant, and also keeping a water content in a dewatered cake constant. SOLUTION: In the multiple screw press, coagulated slurry to the screw press (1) is fed while controlling the pressure to be applied constant, further, the water content (W) in a dewatered cake exhausted from the screw press (1) is measured while continuing the operation of controlling the number of revolutions (M) of the screw shaft (3) constant and also keeping the feed flow rate of a raw liquid constant, and a chemical feed rate (A) is changed to keep the water content (W) in the dewatered cake uniform and constant. It is also possible that the number of revolutions (Na, Nb) of respective outer cases (2a, 2b) are individually controlled, and a difference in the water content in each dewatered cake exhausted from a plurality of screw presses can be made zero; thus the water content (W) in each dewatered cake can be kept at the uniform optimum value in accordance with the change in the properties of sludge. COPYRIGHT: (C)2009,JPO&INPIT
03/22/2007 00:00:00
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1.7.17 Screw press
SCREW PRESS DEWATERING APPARATUS
PROBLEM TO BE SOLVED: To apply the oscillation suitable for preventing filtering holes from being clogged to a filtering cylinder by a simple structure in a screw press dewatering apparatus comprising the filtering cylinder having a large number of filtering holes, a screw provided in the filtering cylinder, and a driving unit to rotate the screw, and applying the compression force to a slurry present between the screw and the filtering cylinder from the upstream side to the downstream side of the screw. SOLUTION: This screw press dewatering apparatus has an exciting device 6 for preventing the filtering holes 2 from being clogged by oscillating the filtering cylinder 3 by applying the blow to the filtering cylinder 3. In addition, the blow, the blowing position and the blowing period are adjustable independently.
10/30/2001 00:00:00
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1.7.18 Screw press
SCREW TYPE DEWATERING APPARATUS FOR IMPROVING DEWATERING EFFICIENCY BY SEPARATION MEANS INCLUDING FIXING RINGS AND CIRCULAR SWING RINGS, DRIVING PLATES INSTALLED ON SEPARATION MEANS AND SUPPORTING BARS FIXED TO DRIVING PLATES
PURPOSE: To provide a screw type dewatering apparatus which shakes swing rings well to improve dewatering efficiency, and in which a swing ring driving means is hardly worn out so that life of the swing ring driving means is substantially extended. CONSTITUTION: The screw type dewatering apparatus comprises a separation tank(10) on both sides of which a sludge supply part and a solid discharge part are formed; a separation means(20) comprising a plurality of fixing rings(21) fixed perpendicularly to an inner part of the separation tank with being distanced from each other in a certain gap, and a plurality of swing rings(22) disposed between the fixing rings with being spaced apart from the fixing rings in a small gap; a separation plate for dividing the separation means into a concentration zone at the sludge supply part side of a space part(S) and a dewatering zone at the solid discharge part side; a screw(30) which is installed in the space part formed in the separation means, and in which an inclined part(32') is formed on an end of the solid discharge part side in such a way that a blade(32) is more inclined to the sludge supply part side as it goes from the center to the outer circumferential surface of the screw; and a swing ring driving means(40) driven with being interlocked with the screw, the swing ring driving means comprising cams(41,41') fixed to both ends of screw shaft, driving plates(44,44') for supporting the center of the cams such that the driving plates are shaken along the contour of the cams at the outside of the cams, and at least three or more supporting bars(45) which fix the swing rings, and both ends of which are fixed to the driving plates so that the swing rings are shaken along the contour of the cams, wherein the supporting bars are closely adhered to the outer circumferential surface of the swing rings such that the supporting rings support the swing rings by controlling the swing rings, and reinforcement rings are installed on an outer surface part of the supporting bars closely adhered to the swing rings to prevent deformation of the supporting bars.
12/29/2004 00:00:00
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1.7.19 Screw press
DEHYDRATED PULP SLURRY AND METHOD OF MAKING

A process for making a dehydrated fruit pulp slurry comprising the steps of a. de-sugaring a fruit pulp slurry, said de-sugaring process producing a washed fruit pulp slurry with a Brix level from 0 °Bx to 1 °Bx, wherein the de- sugaring step comprises a multi-stage concurrent washing process comprising at least two washing stages; and b. dehydrating said fruit pulp slurry, said dehydration process producing a dehydrated fruit pulp slurry with a moisture content of less than 10 wt% of the dehydrated fruit pulp slurry, and comprising a dewatering step comprising mechanical dewatering, chemical dewatering and/or enzymatic dewatering, and further comprising a drying step wherein the temperature of the pulp in the de-sugared pulp slurry does not exceed 60°C or 80°C, wherein the dehydrated fruit pulp slurry produced by said process is such that, when reconstituted, the color, shape and texture of the pulp contained therein is substantially the same as it was prior to undergoing dehydration. The process of claim 1 wherein de-sugaring said fruit pulp slurry results in a Brix level from 0.1 °Bx to 0.5 °Bx. The process of claim 1 wherein the dewatering step comprises chemical dewatering, said chemical dewatering comprising contacting hydrated lime with said washed fruit pulp slurry for a period of time. The process of claim 3 wherein the hydrated lime and the washed fruit pulp slurry are contacted for between 1 to 5 minutes. The process of claim 3 wherein the amount of hydrated lime in the washed fruit pulp slurry and hydrated lime mixture, is no more than 0.02 wt% of the total weight of washed fruit pulp slurry and hydrated lime mixture. The process of claim 1, wherein the mechanical dewatering comprises using a screw presser and wherein the screw presser has a pitch of between 20 degrees and 25 degrees. The process of claim 1 wherein the dewatering step comprises mechanical dewatering, said mechanical dewatering comprising dewatering with a screw presser, wherein the screw presser preferably comprises a wedgewire screen with a slot width of 0.016 inches (0.041 cm) to 0.018 inches (0.046 cm), or 0.018 inches (0.046 cm) to 0.020 inches (0.051 cm) or 0.020 inches (0.051 cm) to 0.025 inches (0.064 cm). The process of claim 1 wherein the dehydrating step comprises fluidized bed drying. The process of claim 8 wherein the fluidized bed drying occurs for between 20 to 30 minutes.
06/14/2011 00:00:00
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1.7.20 Screw press
Dewatering biomass material comprising polysaccharide, method for extracting polysaccharide from biomass material, and dewatered

1. A process for dewatering a starting biomass material comprising a pectin and water, the process comprising:comminuting the starting biomass material;wetting the starting biomass material with a wetting composition comprising an alcohol to form a biomass slurry, wherein the alcohol is ethanol, isopropanol, or a combination thereof and is present in the wetting composition in an amount from about 40 to about 96% by weight of the wetting composition;mechanically separating at least a first portion of the wetting composition, water, or a combination thereof from the biomass slurry to form a wetted biomass material; andmechanically separating at least a second portion of the wetting composition, water, or a combination thereof from the wetted biomass material by pressing the wetted biomass material to form a dewatered biomass material, the dewatered biomass material comprising a greater percentage by weight of dry matter than the starting biomass material,wherein the starting biomass material is selected from the group consisting of citrus peel, apple pomace, sugar beet residue from sugar production, sun flower residue from sun flower oil production, and potato residue from starch production. 2. The process of claim 1, wherein the wetting step comprises washing the biomass material with the wetting composition. 3. The process of claim 2, wherein the washing has a duration of about 10 minutes to about 30 minutes. 4. The process of claim 1, wherein the wetting step comprises washing the biomass material with the wetting composition with a plurality of washings, and the step of mechanically separating at least a portion of the wetting composition, water, or a combination thereof from the biomass slurry comprises mechanically separating at least a portion of the wetting composition, water, or a combination thereof from the biomass slurry after each of the plurality of washings. 5. The process of claim 4, wherein the concentration of alcohol present in the wetting composition increases from the first of the plurality of washings to the last of the plurality of washings. 6. The process of claim 1, wherein the plurality of washings comprise 2 to 4 washings. 7. The process of claim 6, wherein the plurality of washings is conducted counter-currently. 8. The process of claim 1, wherein the step of mechanically separating at least a portion of the water from the wetted biomass material is carried out such that the dewatered biomass material comprises dry matter in an amount from about 35 to about 60% by weight of the dewatered biomass material. 9. The process of claim 1, wherein the step of mechanically separating at least a portion of the water from the wetted biomass material comprises pressing the wetted biomass material by applying a pressure from about 0.5 bar to about 8 bar for a duration from about 1 minute to about 25 minutes. 10. The process of claim 1, wherein the step of mechanically separating at least a portion of the water from the wetted biomass material comprises pressing the wetted biomass with a screw press. 11. The process of claim 1, further comprising drying the dewatered biomass material with heat after the step of mechanically separating at least a portion of the wetting composition, water, or combination thereof from the wetted biomass material to form a dried dewatered biomass material. 12. The process of claim 1, further comprising extracting at least a portion of the pectin from the dewatered biomass material. 13. The process of claim 12, further comprising drying the dewatered biomass material with heat after the step of mechanically separating at least a portion of the wetting composition, water, or a combination thereof from the wetted biomass material, but before the extraction step, to form a dried dewatered biomass material. 14. The process of claim 12, wherein the steps of wetting and mechanically separating are conducted at first location, the pectin extracting step is conducted at a second location remote from the first location, and the process further comprises transporting at least a portion of the dewatered biomass material from the first location to the second location. 15. The process of claim 12, wherein the pectin is extracted from the dewatered biomass material with a pectin yield of greater than 30%. 16. A process for dewatering a starting biomass material comprising a carrageenan and water, the process comprising:comminuting the starting biomass material comprising a red seaweed; wetting the starting biomass material with a wetting composition comprising an alcohol to form a biomass slurry, wherein the alcohol wherein the alcohol is ethanol, isopropanol, or a combination thereof and is present in the wetting composition in an amount from about 40 to about 85% by weight of the wetting composition;mechanically separating at least a first portion of the wetting composition, water, or a combination thereof from the biomass slurry to form a wetted biomass material; andmechanically separating at least a second portion of the wetting composition, water, or a combination thereof from the wetted biomass material by pressing the wetted biomass material to form a dewatered biomass material, the dewatered biomass material comprising a greater percentage by weight of dry matter than the starting biomass material. 17. The process of claim 16, wherein the wetting step comprises washing the biomass material with the wetting composition. 18. The process of claim 17, wherein the washing has a duration of about 10 minutes to about 30 minutes. 19. The process of claim 16, wherein the wetting step comprises washing the biomass material with the wetting composition with a plurality of washings, and the step of mechanically separating at least a portion of the wetting composition, water, or a combination thereof from the biomass slurry comprises mechanically separating at least a portion of the wetting composition, water, or a combination thereof from the biomass slurry after each of the plurality of washings. 20. The process of claim 19, wherein the concentration of alcohol present in the wetting composition increases from the first of the plurality of washings to the last of the plurality of washings. 21. The process of claim 16, wherein the plurality of washings comprise 2 to 4 washings. 22. The process of claim 21, wherein the plurality of washings is conducted counter-currently. 23. The process of claim 16, wherein the step of mechanically separating at least a portion of the water from the wetted biomass material is carried out such that the dewatered biomass material comprises dry matter in an amount from about 35 to about 60% by weight of the dewatered biomass material. 24. The process of claim 16, wherein the step of mechanically separating at least a portion of the water from the wetted biomass material comprises pressing the wetted biomass material by applying a pressure from about 0.5 bar to about 8 bar for a duration from about 1 minute to about 25 minutes. 25. The process of claim 16, wherein the step of mechanically separating at least a portion of the water from the wetted biomass material comprises pressing the wetted biomass with a screw press. 26. The process of claim 16, further comprising drying the dewatered biomass material with heat after the step of mechanically separating at least a portion of the wetting composition, water, or combination thereof from the wetted biomass material to form a dried dewatered biomass material. 27. The process of claim 16, further comprising extracting at least a portion of the carrageenan from the dewatered biomass material. 28. The process of claim 27, further comprising drying the dewatered biomass material with heat after the step of mechanically separating at least a portion of the wetting composition, water, or a combination thereof from the wetted biomass material, but before the extraction step, to form a dried dewatered biomass material. 29. The process of claim 27, wherein the steps of wetting and mechanically separating are conducted at first location, the pectin extracting step is conducted at a second location remote from the first location, and the process further comprises transporting at least a portion of the dewatered biomass material from the first location to the second location.
10/31/2012 00:00:00
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1.7.21 Screw press
Dewatering process

1. A process of dewatering an aqueous sewage sludge suspension employing a flocculating system comprisingi.) treating the suspension with a flocculating amount of a first flocculant having a molecular weight of at least one million and a dewatering amount of a second flocculant, which second flocculant is in the form of particulates,ii.) thickening the treated suspension of step i.) by release of free water,iii.) mixing the thickened suspension, wherein the second flocculant particulates are distributed throughout the thickened suspension of step ii.), using mixing equipment, andiv.) subjecting the suspension to mechanical compression dewatering to form a cake, wherein the first flocculant brings about flocculation and assists thickening of the suspension and the second flocculant further dewaters the suspension,characterised in that the second flocculant is a water-soluble or water swellable polymer formed from 80 to 100% by weight methyl chloride quaternary ammonium salt of dimethyl amino ethyl (meth)acrylate and 0 to 20% by weight acrylamide of intrinsic viscosity between 3 and 10 dl/g that is mixed into the suspension in the form of a water-soluble or water swellable particulate polymer having a particle diameter of at least 50 microns, wherein the first and second flocculants are not counterionic and the first flocculant is cationic acrylamide polymer. 2. A process according to claim 1 in which the compression dewatering employs an apparatus selected from the group consisting of belt press, filter press, screw press and centrifuge. 3. A process according to claim 1 in which the first flocculant and second flocculant are added substantially simultaneously. 4. A process according to claim 1 in which the first flocculant and second flocculant are combined into a single composition. 5. A process according to claim 4 in which the single composition is a particulate polymer product in which the first flocculant comprises particles having a diameter below 10 microns. 6. A process according to claim 1 in which the second flocculant comprises polymeric particles having a coating applied to the surface. 7. A process according to claim 6 in which the coating is a silicone. 8. A process according to claim 6 in which the coating is a water-soluble wax. 9. A process according to claim 1 in which the second flocculant is introduced into the suspension in form of a slurry in a liquid. 10. A process according to claim 9 in which the liquid is polyethylene glycol. 11. A process according to claim 1, wherein the second flocculant is a polymer of intrinsic viscosity between 4 and 10 dl/g. 12. A process according to claim 1, wherein the second flocculant is a particulate polymer having a particle diameter between 100 and 800 microns. 13. A process according to claim 1, wherein thickened suspension in step ii.) is a semi solid sludge paste.
02/28/2005 00:00:00
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1.7.22 Screw press
Method for preparing fermentable sugar from wood-based biomass

1. A method for preparing fermentable sugar from lignocellulosic biomass for use in fermentation of industrial microorganisms, consisting of the steps of: 1) adding water to coarsely ground or powder lignocellulosic biomass having an average particle diameter of 0.1 mm to 50 mm or powdered lignocellulosic biomass to produce a first mixture, heating the mixture at 95 to 140° C. for 1 to 60 minutes, and then dewatering the mixture before the first mixture cools down to produce a first solid residue; 2) adding water to the solid residue obtained in step 1), and subjecting the mixture to autohydrolysis pretreatment at 170 to 210° C. for 1 to 30 minutes; 3) subjecting the autohydrolyzed material obtained in step 2) to solid-liquid separation to obtain a solid residue containing an amount of 5 to 30 wt % based on the total amount of the liquid part of the autohydrolyzed material produces in the pretreatment process; 4) subjecting the solid residue obtained in step 3) to enzymatic saccharification at a temperature of 45 to 55° C. using a cellulase complex enzyme; 5) repeating solid-liquid separation and extraction using the saccharified material obtained in step 4) to obtain a sugar solution; and 6) subjecting the sugar solution obtained in step 5) to filtration, concentration and then impurity removal. 2. The method of claim 1 , wherein the weight ratio of the coarsely ground or powder lignocellulosic biomass having an average particle diameter of 0.1 mm to 50 mm or powdered lignocellulosic biomass to water in step 1) is in a range of 1:4 to 1:20. 3. The method of claim 1 , wherein the solid-liquid separation in step 3) is carried out by centrifugation, suction filtration or pressure filtration. 4. The method of claim 1 , wherein the recovery of the sugar solution of step 5) is carried out by batch type or continuous centrifugation, filter press or screw press. 5. The method of claim 1 , wherein the filtration, concentration and impurity removal of the sugar solution in step 6) are carried out by a membrane separation technique using a reverse osmosis membrane. 6. The method of claim 1 , wherein the fermentable sugar obtained in step 6) contains glucose in an amount of at least 30%.
12/26/2013 00:00:00
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1.7.23 Screw press
Process for dewatering microfibrillated cellulose

1. A process for dewatering a slurry comprising a microfibrillated cellulose by only subjecting the slurry to a mechanical pressure, without significant hornification of the microfibrillated cellulose, wherein the process comprises the following steps: providing a slurry comprising a microfibrillated cellulose and a liquid, subjecting the slurry to a first mechanical pressure in order to dewater the slurry, and subjecting the slurry to a second mechanical pressure which second pressure is higher than the first pressure. 2. The process according to claim 1 wherein the process further comprises the step of subjecting the slurry to a third mechanical pressure which third pressure is higher than the second pressure. 3. The process according to claim 1 , wherein the slurry is conducted between two wires before the slurry is subjected to the first mechanical pressure. 4. The process according to claim 1 , wherein the slurry is subjected to the first and second mechanical pressure by conducting the slurry through a wedge gap. 5. The process according to claim 1 , wherein the slurry is subjected to the first and second pressure by conducting the slurry over a roll having a first roll diameter. 6. The process according to claim 5 wherein the slurry is subjected to the second mechanical pressure by conducting the slurry over a roll having a second roll diameter said second roll diameter being smaller than the first roll diameter. 7. The process according to claim 6 wherein the slurry is conducted over more than one roll having a second roll diameter. 8. The process according to claim 1 , wherein the slurry is subjected to the first and second mechanical pressure by conducting the slurry to a decanter- centrifuge. 9. The process according to claim 1 , wherein the slurry is subjected to the second mechanical pressure by conducting the slurry to a screw press. 10. The process according to claim 1 , wherein the dry content of the slurry comprising a microfibrillated cellulose before the dewatering is 0.1-10% by weight. 11. The process according to claim 1 , wherein the dry content of the dewatered slurry comprising a microfibrillated cellulose is 1-50% by weight.
11/05/2014 00:00:00
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2. Force and/or temperature based approaches

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Dewatering methods based on force and/or temperature without filtration. 


2.1 Centrifugation

0

Centrifugation is the technique which involves the application of centrifugal force to separate particles from a solution according to their size, shape, density, viscosity of the medium and rotor speed. [\[link\]](https://en.wikipedia.org/wiki/Centrifugation) A *decanter centrifuge* (also known as solid bowl centrifuge) separates continuously solid materials from liquids in the slurry, and therefore plays an important role in the wastewater treatment, chemical, oil, and food processing industries. A scroll (also **screw or screw conveyor**) rotates inside the bowl at a slightly different speed. [\[link\]](https://en.wikipedia.org/wiki/Decanter_centrifuge) **Note:** thermal treatments combined with centrifugation are included here. **Highlights:** * It is demonstrated that the most efficient dewatering may be expected using centrifugal filtration of the cakes initially dewatered in vacuum filters. During large-scale laboratory researchers of centrifugal decantation, a considerably **lower final moisture content** of the product has been achieved than in vacuum or pressure filtration. Furthermore, it has been shown that the **dewatering costs of the system are lower** than in the case of vacuum filtration and subsequent drying. [\[Art. #ARTNUM\]](#article-96004-2050959095) * **Microalgae-based** biofuels have the potential to replace fossil fuels and contribute towards carbon sequestration. \[...\] Dewatering is a critical stage which accounts for 20–30% of biofuels‘ production costs, therefore a **techno-economic assessment** of two dewatering cases was conducted. The first case was a conventional **clarifier-centrifuge dewatering system** (Case 1), while the second case investigated a single stage dewatering approach, using the wet-end of a paper machine (Fourdrinier former; Case 2).[ \[Art. #ARTNUM\]](#article-96004-2944360062) * Method for **large-scale processing of biomass**, in which the biomass is subjected to at least one comminution step, wherein the at least one comminution step is carried out by means of a water cutter operated with a liquid, wherein biomass is metered into the water cutter in a feed step by means of a feed apparatus (3), which has a conveyor spindle or **conveyor screw.** [\[Art. #ARTNUM\]](#article-96004-EP2977106B1) * European patent * The invention discloses an **automatic instant high pressure centrifugal dewatering** vaporizing compression slurry solidification system. \[...\] solidified slurry has small water content, thus being **energy saving** and environment-friendly.[ \[Art. #ARTNUM\]](#article-96004-2819673757) * Chinese patent **Combinations:** * According to a **high-efficiency centrifugal dehydrator** for improving dewaterability of the present invention, a single ring-shaped blocking plate is disposed between a sludge discharge port of a screw conveyor in a centrifugal dehydrator drum and a cake discharge port of the drum so that a dehydration area in the drum can be narrowed, the pressure of the **screw** conveyor is maximized, and dehydration efficiency can be increased. [\[Art. #ARTNUM\]](#article-96004-2821153370) * Patent Ecoset * Organic substrates such as **grain by-products:** wet cake, mash, stillage, wet brewers cake are dewatered in a relatively low energy, low-heated gas flow, negative pressure, four stage process consisting of **leaching** with organic solvent, mechanical dewatering, evaporation and reclamation of the organic solvent in an environment of a stable gas flow [\[Art. #ARTNUM\]](#article-96004-2278385315) * US patent **Combined with thermal treatment:** * A new sewage sludge semi-drying (dewatering) process is proposed and verified. It **combines thermal hydrolysis** and subsequent mechanical dewatering, with **less energy consumption** than traditional thermal drying. Sludge treated using this new process satisfies further disposal requirements (e.g., landfill or autothermal incineration). \[...\] Thermally hydrolyzed sludge was subsequently dewatered by centrifugal sedimentation or by pressure filtration. \[...\] The moisture content then dropped to **1.44 kg/kg dry solids (DS; 59 wt%)** after dewatering under relative centrifugal force of 9,000 × g from 5.67 kg/kg DS (85 wt%). [\[Art. #ARTNUM\]](#article-96004-2028845792) * **Hydrothermal treatment** could **disrupt sludge cell** and release bound water finally improve sludge dewaterability. In this paper, bench scale experiments of sludge hydrothermal treatment were carried out. Results show that under a temperature from 140∞C to 180∞C and reaction time from 15min to 90min, **water content** of treated sludge could **reduce from 80% to about 50%.** \[...\] The sludge was heated by high temperature steam generated form a boiler under 180∞C. The treated sludge was dewatered by a centrifuge. [\[Art. #ARTNUM\]](#article-96004-2625584478) **Other treatments:** * The study experimentally investigated the centrifugal separation of moisture from activated sludge subject to **cationic polyelectrolyte flocculation**. An arm-suspended centrifuge was employed which allowed in-situ detection on all positions of interfaces of centrifuged sludge as functions of time. Experimental results revealed that, sludge flocculation would yield a significant sedimentation effect at the first phase of centrifugation. [\[Art. #ARTNUM\]](#article-96004-1977816390) * Two automatic hydraulic backdrives and a direct current automatic torque controlled backdrive were tested on **centrifuges** used for dewatering digested sludge conditioned with a **polymer** and a combination of polymer and **ferric chloride**. The centrifuge unit of an advanced design coupled with the direct current automatic torque controlled backdrive produced a cake having a solids content of 30% and a **solids capture of 97%**. The regular production unit produced a cake having a solids content of 15% and a solids capture of 85%.[ ](#article-96039-2804237639)[\[Art. #ARTNUM\]](#article-96004-2804237639) * This research assessed the potential for **orifice flow treatment** to improve biosludge dewaterability by disintegrating the flocs, thereby releasing the interstitial water trapped within them. Pulp and paper waste activated sludge, municipal waste activated sludge, and municipal anaerobically digested sludge samples were orifice flow treated \[...\] Overall, orifice flow treatment worsened filterability. Orifice flow treatment did, however, **increase the** **centrifuge cake solids content** of pulp and paper and municipal waste activated sludge by **10 and 15 %** respectively, showing the potential to improve biosludge centrifugability.[ \[Art. #ARTNUM\]](#article-96004-2558687895)

2.1.1 Centrifugation
An Improved Dewatering Performance in Cassava Starch Process by a Pressure Filter
As part of an ongoing study to improve the cassava starch manufacturing process, a potential improvement to the dewatering stage was explored. Two types of starch dewatering were compared, a pressure filter and a conventional centrifuge. Performance with respect to the dewatering efficiency of the starch slurry, implied by the filtration rate and percentage of dry solids in circulation, was measured for a pressure filter and a conventional centrifuge. For the pressure filter, effect of different filter cloths, feed time and pressing time were evaluated. At all filtering conditions, the pressure filter provided improved dewatering efficiency. The filtration rate significantly increased from 162 to 226 g m -2 s -1 and starch loss, to the circulation, notably decreased from 15 to 0.15%. Improvement in processing-efficiency did not sacrifice starch quality. Granule morphology and functional properties, such as paste viscosity, water adsorption, and solubility characteristics remained unchanged. One notable exception was that chemical compounds and microorganisms appeared to he more readily absorbed to the granule surface. The pressure filter not only improved dewatering efficiency but also minimized production cost due to a lower starch cake moisture, which requires less energy consumption for subsequent drying.
12/01/1999 00:00:00
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2.1.2 Centrifugation
Automatic instant high pressure centrifugal dewatering vaporizing compression slurry solidification system
The invention discloses an automatic instant high pressure centrifugal dewatering vaporizing compression slurry solidification system. The system comprises a slurry pool and a conveyer belt, and intercommunicated feeding equipment, atomization equipment, high temperature drying pressure equipment and compression equipment are arranged between the slurry pool and the conveyer belt in order, wherein the feeding equipment is used for feeding of slurry, the slurry undergoes high pressure centrifugal dewatering by a high pressure sieve membrane centrifugal dewaterer, and the slurry subjected to high pressure centrifugal dewatering heating, pressurizing and jetting; the atomization equipment is used for dewatering and atomization again on the fed slurry; the high temperature drying pressure equipment is used for heating of the fed slurry and repeated conveying rolling dewatering drying; and the compression equipment is used for compression and extrusion of the dried slurry. The slurry solidification system provided by the invention has the advantages of reasonable structure and convenient operation, realizes solidification treatment on a variety of slurries with different soil properties, at the same time the solidified slurry has small water content, thus being energy saving and environment-friendly. Moreover, the system provided by the invention has a light structure, and is suitable for mobile application at construction sites.
10/20/2017 00:00:00
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2.1.3 Centrifugation
Centrifugal Dewatering and Reconstitution of Fine Coal: The GranuFlow Process
This paper describes the continuous bench-scale testing of the GranuFlow Process, developed and patented by the Pittsburgh Energy Technology Center (PETC) of the U.S. Department of Energy. Testing was conducted on both high-g force solid-bowl and screen-bowl centrifuges for dewatering and reconstitution of fine-clean-coal slurry at 300 Ib/h (136 kg/hr) in PETC7's Coal Preparation Process Research Facility. In the GranuFlow Process, fine-clean-coal slurry was treated with a bitumen emulsion before dewatering in both centrifuges. In one example, the treated products from a solid-bowl centrifuge appeared to be dry and in a free-flowing granular form, while the untreated products were wet, lumpy, sticky, and difficult to handle. Specifically, test results from the solid-bowl centrifuge indicated that the moisture content, handleability, and dust reduction of the dewatered coal product improved as the addition of emulsion increased from 2 wt% to 8 wt%. The improvement in handleability was most visible for the ...
01/01/1996 00:00:00
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2.1.4 Centrifugation
Characterization and dewaterability of raw and stabilized sludge using different treatment methods.
A comparison of the characteristics and stabilization potential of the four most used sludge treatment systems in Mexico was made. A pilot plant constituted by separate systems for anaerobic and aerobic digestion, lime stabilization, conditioning and dewatering, was built and operated during four months in one of the biological wastewater treatment plants in Acapulco, Mexico. Composting of sludge was also made. An aerobic static pile was built using bulking materials available in the region. A turbine centrifuge was used for dewatering the stabilized sludge and results showed good performance of the device. The main problem for the beneficial use of treated sludge was its pathogenicity. The composting process allowed us to obtain a product with approximately 20 fecal coliform density (MPN/g); with lime stabilization, the sludge produced had a fecal coliform density of 2 MPN/g. From these results, it is concluded that both the composting process and the alkaline stabilization with lime produce a well stabilized sludge, bacteriologically safe that accomplishes the requirements for its use on soil without restrictions. Related to parasitological removal, the best helminth egg removals were obtained also using these two processes. Ascaris sp. densities in raw sludge (309-430 eggs/g) were reduced to a final density of 3-14 eggs/g in the aerobic composting process and to 4-18 eggs/g in the lime stabilized sludge. Removal is not high enough to reach the recommended level for unrestricted use of stabilized sludge.
11/01/2002 00:00:00
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2.1.5 Centrifugation
Dewatering Chemical-Primary Sludges
The efficiency and the cost of dewatering lime and alum generated physical-chemical treatment sludge were developed utilizing a continuous vacuum filter and a solid bowl conveyor centrifuge. Centrifugal dewatering included evaluation of both single-stage and two-stage classification dewatering. The evaluation of the data showed that lime recovery was economical with both a single and two-state centrifugal as well as vacuum filter above the plant size of 25,000,000 gal/day. Tables show the comparative cost of dewatering the lime and alum sludges for various sizes of treatment plants and with costs itemized for capital and operating considerations. Vacuum filters are the least-cost approach based on the results of the field studies. The paper also shows the process effects of varying operating parameters for these centrifuge and vacuum filter operations.
10/01/1976 00:00:00
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2.1.6 Centrifugation
DEWATERING OF WASTE ACTIVATED SLUDGE VIA CENTRIFUGAL FIELD
ABSTRACT While conducting centrifugal dewatering tests on waste activated sludge, this work considered how the rotational speed and the application of cationic polyelectrolyte flocculation affected the sludge. Increased rotational speed and/or conditioning the sludge to a charge neutralization point could enhance dewatering efficiency. A model was proposed to estimate the disruption energy exerted on the sludge body using centrifugation. Experimental results indicate that the disruption energy level provided by the centrifuge increases with rotational speed and decreasing water content in the filter cake. Moreover, polyelectrolyte flocculation may significantly reduce the disruption energy level of the water from sludge particles and the residual water contents at the end of the test.
06/27/2002 00:00:00
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2.1.7 Centrifugation
Effect of temperature on biogas yield increase and formation of refractory COD during thermal hydrolysis of waste activated sludge
Abstract Thermal hydrolysis (TH) increases the anaerobic biodegradability of waste activated sludge (WAS), but also refractory organic and nutrient return load to a wastewater treatment plant (WWTP). This could lead to an increase in effluent chemical oxygen demand (COD) of the WWTP. The aim of this study was to investigate the trade-off between increase in biogas production through TH and anaerobic digestion and increase in refractory COD in dewatered sludge liquors at different temperatures of TH in lab-scale. WAS was thermally hydrolyzed in temperature range of 130–170 °C for 30 min to determine its biomethane potential (BMP). After BMP test, sludge was dewatered and sludge liquor was aerated in Zahn-Wellens test to determine its non-biodegradable soluble COD known as refractory soluble COD (sCODref). With increasing temperature in the range of 130–170 °C, BMP of WAS increased by 17–27%, while sCODref increased by 3.9–8.4%. Dewaterability was also enhanced through relative increase in cake solids by 12–30%. A conversion factor was defined through mass balance to relate sCODref to volatile solids of raw WAS. Based on the conversion factor, expected increase in effluent CODs of six WWTPs in Berlin were predicted to be in the range of 2–15 mg/L after implementation of TH at different temperatures. It was concluded that with a slight decrease in temperature, formation of sCODref could be significantly reduced, while still benefiting from a substantial increase in biogas production and dewaterability improvement.
03/01/2020 00:00:00
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2.1.8 Centrifugation
Energy demand in sludge dewatering
This work investigates the energy required to dewater a suspension, i.e., activated sludge dewatered by centrifugation or consolidation. Total energy input to the suspension from the dewatering device, bond strength between adjacent water and solid surface, and intra-cake friction loss were evaluated for original and flocculated sludges. In centrifugal dewatering, most energy input during the initial stage was consumed by overcoming process irreversibility other than intra-cake friction, and, thereby, had a low energy efficiency. To increase centrifuge speed or to flocculate the sludge at optimal flocculant dosage would yield a high-energy input. In the consolidation test, most energy input at the initial stage was consumed in breaking down the bond strength until the moisture content reduced to less than the critical content. During subsequent dewatering stages, friction loss became the dominant source of energy loss. Dewatering sludge with high-energy efficiency is beneficial to optimally operate a dewatering process.
05/01/2005 00:00:00
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2.1.9 Centrifugation
Enhanced ultrafine coal dewatering using flocculation filtration processes
Abstract Ultrafine coal (−150 μm) can be effectively cleaned using advanced separation techniques such as column flotation, however, dewatering it to below 20 percent moisture level using the conventional dewatering techniques is difficult. A comparative flocculation filtration study was performed for enhancing dewatering of ultrafine coal using vacuum, hyperbaric, and centrifugal filters. The cationic and anionic flocculants were added into the slurry individually or in combinations. Vacuum filtration results showed that use of flocculants increased filtration rate by several times and/or substantially reduced cake moisture. Combined use of anionic and cationic flocculants showed further improvement. Addition of flocculants significantly increased filtration rate of hyperbaric filtration and reduced cake moisture in centrifugal filtration. Anionic flocculant was more effective in enhancing fine coal dewatering than cationic flocculant in vacuum filtration while cationic flocculant was more effective in high shear centrifugal filtration. A new approach on using flocculants in vacuum filtration is proposed for enhanced fine coal dewatering.
02/01/2000 00:00:00
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2.1.10 Centrifugation
Enhancing the dewaterability of anaerobically digested sludge using fibrous materials recovered from primary sludge: demonstration from a field study
Sludge dewatering is an important process for determining the operation cost of sludge disposal. Hence, improving the dewaterability of anaerobically digested sludge containing high water content is of paramount significance. For this challenge, we developed a novel process in which fibrous materials initially collected from a primary sedimentation tank, namely recovered fibers, were used as an auxiliary agent to improve the dewaterability of anaerobically digested sludge. The objective of this study was to investigate the feasibility of using the developed process to improve sludge dewaterability. Three fibrous materials individually recovered from the respective primary sedimentation tanks in different wastewater treatment plants (WWTPs) were used to investigate sludge dewaterability, organic C compositions, and calorific values. The recovered fibers showed comparable compositions irrespective of the WWTP. Six different WWTP sludge samples after anaerobic digestion were continuously supplied to three different dewatering devices, i.e., screw press, centrifuge, and belt press machines, with or without the supply of recovered fibers. Irrespective of the type of a dewatering device, the supply of recovered fibers mixed with the tested sludge samples at a feed ratio of 0.18–0.20 g-fibers/g-sludge (dry weight) reduced the amount of polymer flocculant by 13–50%, thereby displaying the superiority of the addition of recovered fibers. Furthermore, at fiber feed ratios of 0.20 g-fibers/g-sludge and 0.40 g-fibers/g-sludge when the rates of sludge supply and polymer flocculant were kept constant, the corresponding water contents in the dewatered sludge cakes decreased to about 74–76% and 69–72%, respectively. The consistent results regardless of the dewatering device or sludge sample showed the significance of the addition of recovered fibers for improvement in sludge dewaterability.
04/24/2019 00:00:00
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2.1.11 Centrifugation
Evaluation of Bacterial Pathogen and Indicator Densities After Dewatering of Anaerobically Digested Biosolids Phase II and III
The sudden increase in indicator bacteria, including fecal coliforms (FCs) and E. coli , was evaluated at several full-scale facilities, in addition to the increase measured during cake storage. The results showed that the sudden increase was a statistically verifiable occurrence at some facilities, but not all, as was the additional increases measured during cake storage. The sudden increase and growth were much more prevalent in processes that utilized centrifuge dewatering compared to belt filter press dewatering. The sudden increase appears to be a result of the reactivation of indicator bacteria that become reversibly non-culturable (RNC) during digestion. Although other hypotheses, such as contamination and presence of inhibitors, cannot be ruled out in all cases. Only one plant that was sampled with high solids centrifugation did not show reactivation and/or regrowth and this plant was different from others in that it utilized thermophilic reactors in series. The results showed a good correlation between the digestion temperature and the reactivation potential and amount of reactivation measured after dewatering. As temperature of digestion increased, the amount of reactivation increased (for plants with reactivation). Similarly, this was generally true, on average for the extent of regrowth. The digestion SRT and VS reduction did not correlate well with reactivation or regrowth. This title belongs to WERF Research Report Series ISBN: 9781780403731 (eBook) ISBN: 9781843397847 (Print)
12/30/2015 00:00:00
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2.1.12 Centrifugation
Experimental analysis of centrifugal dewatering process of polyelectrolyte flocculated waste activated sludge.
The study experimentally investigated the centrifugal separation of moisture from activated sludge subject to cationic polyelectrolyte flocculation. An arm-suspended centrifuge was employed which allowed in-situ detection on all positions of interfaces of centrifuged sludge as functions of time. Experimental results revealed that, sludge flocculation would yield a significant sedimentation effect at the first phase of centrifugation. Therefore, not as suggested in conventional centrifugal-filtration models, the most significant moisture-removal stages included filtrate to flow through a wet cake. Moreover, an optimal rotational speed exists at which the moisture-removal rate reaches a maximum value. New theories/correlations are required to describe centrifugation dewatering of polyelectrolyte flocculated sludge.
07/01/2001 00:00:00
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2.1.13 Centrifugation
Experimental Study on Thermal Hydrolysis and Dewatering Characteristics of Mechanically Dewatered Sewage Sludge
After mechanical dewatering, sewage sludge has a moisture content of around 80 wt% and further disposal is required. A new sewage sludge semi-drying (dewatering) process is proposed and verified. It combines thermal hydrolysis and subsequent mechanical dewatering, with less energy consumption than traditional thermal drying. Sludge treated using this new process satisfies further disposal requirements (e.g., landfill or autothermal incineration). In the present study, a high-pressure test reactor was used to study the thermal hydrolysis of dewatered sludge. Thermally hydrolyzed sludge was subsequently dewatered by centrifugal sedimentation or by pressure filtration. The amount of organic compounds returning to the water phase was also measured. According to the results from centrifugal settling tests, the optimal thermal hydrolysis treatment temperature was 180°C. The moisture content then dropped to 1.44 kg/kg dry solids (DS; 59 wt%) after dewatering under relative centrifugal force of 9,000 × g from 5.6...
11/01/2011 00:00:00
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2.1.14 Centrifugation
HIGH EFFICIENCY DEWATERING DECANTER CENTRIFUGE TO IMPROVE DEWATERABLITY
According to a high-efficiency centrifugal dehydrator for improving dewaterability of the present invention, a single ring-shaped blocking plate is disposed between a sludge discharge port of a screw conveyor in a centrifugal dehydrator drum and a cake discharge port of the drum so that a dehydration area in the drum can be narrowed, the pressure of the screw conveyor is maximized, and dehydration efficiency can be increased. Also, the conical angle of the drum having a conical shape is adjusted to be increased so that the dehydration area is narrowed and a filtering area is lengthened, the dehydration effect is increased by raising the pressure received by the dehydration area, a filtrate treatment performance is improved, and a sludge treatment amount is increased. The ring-shaped blocking plate that is applied to the present invention is made of stainless steel, and maximizes the dehydration effect by separating a solid material from filtrate, narrowing the dehydration area, and receiving a higher pressure. The outer diameter of the blocking plate is changed by the volume ratio of the concentration of the sludge to be treated and can vary by centrifugal dehydrator model. Also, an additional suspension separation means is configured to be in the drum according to the present invention.
08/01/2014 00:00:00
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2.1.15 Centrifugation
Improve Sludge Dewatering Performance byHydrothermal Treatment
In China, over 14.3 million tons dewatered sewage sludge, with 80% water content, generated from wastewater treatment plants in 2007. Traditional technologies used by municipal solid waste treatment facilities, such as landfill, composting, incineration, are unsuitable for sludge disposal. High water content is the bottleneck of sludge treatment and disposal. Hydrothermal treatment could disrupt sludge cell and release bound water finally improve sludge dewaterability. In this paper, bench scale experiments of sludge hydrothermal treatment were carried out. Results show that under a temperature from 140∞C to 180∞C and reaction time from 15min to 90min, water content of treated sludge could reduce from 80% to about 50%. Based on laboratory parameters, a full scale project of hydrothermal process was carried out to treat 30 tons dewater sludge per day. The sludge was heated by high temperature steam generated form a boiler under 180∞C. The treated sludge was dewatered by a centrifuge. Water content of 54.66% was obtained in the full scale project.
01/01/2010 00:00:00
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2.1.16 Centrifugation
Improved Centrifuge Sludge Dewatering by Automatic Backdrive Torque Control
An investigation of different automatic torque control systems for performance optimization of solid bowl centrifuges was conducted at the Stickney Water Reclamation Plant of the Metropolitan Water Reclamation District of Greater Chicago (District). Two automatic hydraulic backdrives and a direct current automatic torque controlled backdrive were tested on centrifuges used for dewatering digested sludge conditioned with a polymer and a combination of polymer and ferric chloride. The centrifuge unit of an advanced design coupled with the direct current automatic torque controlled backdrive produced a cake having a solids content of 30% and a solids capture of 97%. The regular production unit produced a cake having a solids content of 15% and a solids capture of 85%.
12/01/1990 00:00:00
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2.1.17 Centrifugation
Life cycle assessment of dewatering routes for algae derived biodiesel processes
Biodiesel derived from algae is considered as a sustainable fuel, but proper downstream processing is necessary to minimize the environmental footprint of this process. Algae is grown in dilute liquid cultures, and achieving the low water contents required for extraction represents one of the greatest challenges for the production of algae derived biodiesel. An analysis of the life cycle emissions associated with harvesting, dewatering, extraction, reaction, and product purification stages for algae biodiesel were performed. This “base case” found 10,500 kg of total emissions per t of biodiesel with 96 % of those attributed to the spray dryer used for dewatering. Alternative cases were evaluated for various sequences of mechanical and thermal dewatering techniques. The best case, consisted of a disk-stack centrifuge, followed by the chamber filter press, and a heat integrated dryer. This resulted in 875 kg emissions/t of biodiesel, a 91 % reduction from the base case. Significant reductions in life cycle emissions were achieved for all mechanical dewatering alternatives compared to the base case, but further improvements using these existing technologies were limited. Additional improvements will require the development of new techniques for water removal or wet extractions.
08/01/2013 00:00:00
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2.1.18 Centrifugation
Mechanical dewatering of the flotation concentrate of coking coal
Abstract Various mechanical methods for dewatering the loatation concentrate of coking coal are discussed, including vacuum, pressure and centrifugal filtration of both the feed slurry and the slurry condensed by sedimentation, and also centrifugal filtration of the cakes obtained during vacuum filtration. It is demonstrated that the most efficient dewatering may be expected using centrifugal filtration of the cakes initially dewatered in vacuum filters. During large-scale laboratory researchers of centrifugal decantation, a considerably lower final moisture content of the product has been achieved than in vacuum or pressure filtration. Furthermore, it has been shown that the dewatering costs of the system are lower than in the case of vacuum filtration and subsequent drying. A secondary effect of the method presented is the reduction in pollution due to confinement of the drying centre.
07/01/1994 00:00:00
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2.1.19 Centrifugation
Method for dehydrating biomass
Organic substrates such as grain by-products: wet cake, mash, stillage, wet brewers cake are dewatered in a relatively low energy, low-heated gas flow, negative pressure, four stage process consisting of leaching with organic solvent, mechanical dewatering, evaporation and reclamation of the organic solvent in an environment of a stable gas flow. The dried organic substrate is processed into a dry distiller's grains with solubles which is free-flowing quality substance suitable for food or other uses at much lower substrate drying temperatures generally below 200° F. Conveniently, the solvent and the stable gases are recovered from the water-solvent leaching and dewatering process by a distillation tower and feedback loop system allowing the recycling of the solvent and stable gas while reducing the level of air emissions in the unique drying system.
03/27/2006 00:00:00
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2.1.20 Centrifugation
Microalgae dewatering for biofuels: A comparative techno-economic assessment using single and two-stage technologies
Abstract Microalgae-based biofuels have the potential to replace fossil fuels and contribute towards carbon sequestration. However, the growth of this industry is challenged by the financial viability of scale-up at various production stages. Dewatering is a critical stage which accounts for 20–30% of biofuels‘ production costs, therefore a techno-economic assessment of two dewatering cases was conducted. The first case was a conventional clarifier-centrifuge dewatering system (Case 1), while the second case investigated a single stage dewatering approach, using the wet-end of a paper machine (Fourdrinier former; Case 2). Mass and energy balances were modelled at a process scale of 175 t/d to produce biomass with 25% dry substance content, from which the associated costs were calculated. The minimum selling price (MSP) to achieve a return of 12% at a corporate tax rate of 30% over a 20-year plant life, was AU$354.28/t and AU$59.68/t for Case 1 and Case 2 respectively. Electricity cost was 90% of operational expenditure for two-stage dewatering and 38% for single stage. Case 2 made a better investment case with an annual profit after tax of AU$131,020 and net present value (NPV) of AU$164 million, as against that of Case 1 with an annual profit after tax of AU$112,610 and NPV of AU$71 million. The single stage dewatering deserves further investigation to fully explore the cost reduction potentials. The adoption of low cost technologies with reduced energy use implies lower embedded GHG emissions and process costs when compared to conventional technologies. This is desired for the near-term actualization of sustainable and clean production pathways for microalgae based biofuels.
08/01/2019 00:00:00
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2.1.21 Centrifugation
Movement of Sludge Through Conveyor Centrifuge
Conveyor centrifuges are widely used for dewatering wastewater sludges. The process requires that sludge be first settled out in the bowl under centrifugal acceleration and then moved by means of an internal conveyor up a beach and out of the machine. The movement of the sludge in the machine has never been observed, and its true path is unknown. The objective of this paper is to present three possible paths for the sludge in a centrifuge and to suggest the most likely mode of movement. The eventual determination of the true path will have implications for design and future development of centrifugal dewatering practice.
08/01/1988 00:00:00
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2.1.22 Centrifugation
Screening study on flocculant for night soil dewatering
Separation of the solid and liquid is a prerequisite for sustainable utilization of night soil or manure.Floculant must be added to improve the poor dewatering capacity.Five kinds of flocculant have been comparatively studied on the effects of night soil settlement and dewatering.Two preferred polyacrylamide were selected to test on line.decanter centrifuge and rotary press were used as dewatering equipment.The results showed that cationic high polymer flocculant with molecular weight greater than 5 million should be chosen instead of inorganic coagulant to flocculate night soil.Dewatering effect of FO4000 of SNF company is superior to others.The optimum dosage of FO4000 is 3~4 kg/t dry solids for decanter centrifuge and 5~7 kg/t dry solids for rotary press.
01/01/2002 00:00:00
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2.1.23 Centrifugation
The Effect of Orifice Flow Treatment on Biosludge Dewaterability
This research assessed the potential for orifice flow treatment to improve biosludge dewaterability by disintegrating the flocs, thereby releasing the interstitial water trapped within them. Pulp and paper waste activated sludge, municipal waste activated sludge, and municipal anaerobically digested sludge samples were orifice flow treated at strain rates up to 29,280  1060 s -1 , 34,540 s -1 , and 34,090 s -1 , respectively, and their particle size distribution, water distribution, and dewaterability were assessed. Although orifice flow treatment disintegrated the biosludge flocs, it did not significantly affect the interstitial water content. Overall, orifice flow treatment worsened filterability. Orifice flow treatment did, however, increase the centrifuge cake solids content of pulp and paper and municipal waste activated sludge by 10 and 15 % respectively, showing the potential to improve biosludge centrifugability. Additionally, orifice flow treatment was more effective in disintegrating pulp and paper waste activated sludge flocs than sonication at the same energy output.
11/01/2015 00:00:00
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2.1.24 Centrifugation
Dewatering process

1. A process of dewatering an aqueous sewage sludge suspension employing a flocculating system comprisingi.) treating the suspension with a flocculating amount of a first flocculant having a molecular weight of at least one million and a dewatering amount of a second flocculant, which second flocculant is in the form of particulates,ii.) thickening the treated suspension of step i.) by release of free water,iii.) mixing the thickened suspension, wherein the second flocculant particulates are distributed throughout the thickened suspension of step ii.), using mixing equipment, andiv.) subjecting the suspension to mechanical compression dewatering to form a cake, wherein the first flocculant brings about flocculation and assists thickening of the suspension and the second flocculant further dewaters the suspension,characterised in that the second flocculant is a water-soluble or water swellable polymer formed from 80 to 100% by weight methyl chloride quaternary ammonium salt of dimethyl amino ethyl (meth)acrylate and 0 to 20% by weight acrylamide of intrinsic viscosity between 3 and 10 dl/g that is mixed into the suspension in the form of a water-soluble or water swellable particulate polymer having a particle diameter of at least 50 microns, wherein the first and second flocculants are not counterionic and the first flocculant is cationic acrylamide polymer. 2. A process according to claim 1 in which the compression dewatering employs an apparatus selected from the group consisting of belt press, filter press, screw press and centrifuge. 3. A process according to claim 1 in which the first flocculant and second flocculant are added substantially simultaneously. 4. A process according to claim 1 in which the first flocculant and second flocculant are combined into a single composition. 5. A process according to claim 4 in which the single composition is a particulate polymer product in which the first flocculant comprises particles having a diameter below 10 microns. 6. A process according to claim 1 in which the second flocculant comprises polymeric particles having a coating applied to the surface. 7. A process according to claim 6 in which the coating is a silicone. 8. A process according to claim 6 in which the coating is a water-soluble wax. 9. A process according to claim 1 in which the second flocculant is introduced into the suspension in form of a slurry in a liquid. 10. A process according to claim 9 in which the liquid is polyethylene glycol. 11. A process according to claim 1, wherein the second flocculant is a polymer of intrinsic viscosity between 4 and 10 dl/g. 12. A process according to claim 1, wherein the second flocculant is a particulate polymer having a particle diameter between 100 and 800 microns. 13. A process according to claim 1, wherein thickened suspension in step ii.) is a semi solid sludge paste.
02/28/2005 00:00:00
Link to Patent
2.1.25 Centrifugation
METHOD AND DEVICE FOR LARGE-SCALE PROCESSING OF BIOMASS

Method for large-scale processing of biomass, in which the biomass is subjected to at least one comminution step, wherein the at least one comminution step is carried out by means of a water cutter operated with a liquid, wherein biomass is metered into the water cutter in a feed step by means of a feed apparatus (3), which has a conveyor spindle or conveyor screw (7), which, in order to hold together the biomass and to adapt its cross section to the clear width of the cutting device of the water cutter, is enclosed on all sides, at least in its output-side end region (8), by a guide surface (9) in the form of a cylinder or cone (10), wherein the water cutter (2) is arranged at the output end (11) of the feed apparatus (3) and cooperates with at least one mating cutter (13) formed at the output end (11) of the feed apparatus (3), wherein a mixture of comminuted biomass and liquid formed in the comminution step is fed to a washing apparatus (19) and the liquid is separated out mechanically from the mixture of comminuted biomass and liquid, or the biomass is comminuted after the washing and the comminuted biomass or the mixture of comminuted biomass and liquid is processed further, i.e. dewatered mechanically, in particular in a press. Method according to Claim 1, characterized in that the liquid is fresh water, service water including waste water, process liquid, in particular from a biogas plant, or manure or a mixture of at least two of the aforementioned liquids and/or is circulated. Method according to Claim 1 or 2, characterized in that the liquid is temperature-controlled before and/or during use, in particular heated, boiled or cooled. Method according to one of the preceding claims, characterized in that the water cutter operates in the range between 60 and 600 bar. Method according to one of the preceding claims, characterized in that the biomass is temperature-controlled before and/or during the processing, in particular heated, boiled, cooled or frozen. Method according to one of Claims 1 to 5, characterized in that the liquid required for the operation of the water cutter is taken from the mixture of comminuted biomass and liquid. Method according to one of the preceding claims, characterized in that the liquid required for the operation of the water cutter is processed before its use, in particular cleaned, and/or temperature-controlled or has its temperature re-adjusted, in particular heated, boiled or cooled. Method according to Claim 7, characterized in that the liquid is washing water, waste water, service water or press water. Device for processing biomass (1), comprising a comminution apparatus (2), which is a water cutter (2) having at least one cutting jet (12), having a feed apparatus (3) from metering the biomass (1) to the water cutter (2), which has a conveyor spindle or conveyor screw (7) which, to hold together the biomass and to adapt its cross section to the clear width of the cutting device of the water cutter (2), is enclosed on all sides, at least in its output-side end region (8), by a guide surface (9) in the form of a cylinder or cone (10), wherein the water cutter (2) is arranged at the output end (11) of the feed apparatus (3) and cooperates with at least one mating cutter (13) formed at the output end (11) of the feed apparatus (3). Device according to Claim 9, characterized in that for the metered feeding of the biomass, a metering apparatus comprising an apparatus (4) for determining the type, composition and density of the biomass (1) fed in is provided in the feed apparatus (3), and an apparatus (5) for regulating the feed rate of the biomass (1) to the water cutter (2) and the intensity of the cutting jet (12) is provided. Device according to Claim 9 or 10, characterized in that the mating cutter (13) is a mating cutter bar (14). Device according to Claim 9 or 10, characterized in that the mating cutter (13) is a further cutting jet (15) directed counter to the cutting jet (12). Device according to one of Claims 9 to 12, characterized in that the cutting jet (12) is guided in an oscillating manner over and/or under and/or at the side of the biomass (1) and/or circumferentially about a stream of the biomass (1) that is fed in. Device according to Claim 12 or 13, characterized in that multiple cutting jets (12, 15) are guided counter to one another as cutters (12) and mating cutters (15). Device according to one of Claims 9 to 14, characterized in that the water cutter (2) is formed at the output end (17) of a conveyor tree (16) of the conveyor spindle (7) so as to rotate about its longitudinal axis (18) in such a way that the cutting jet (12, 15) is directed substantially radially outwards. Device according to Claim 9 or 10, characterized in that the feed apparatus (3) has a metering container, the biomass being cut in the region of its discharge. Device according to Claim 15 or 16, characterized in that the mating cutter (13) provided is an oppositely directed cutting jet (15, 12) directed radially inwards and circulating around the stream of the biomass (1) synchronously with the cutting jet (12). Device according to one of Claims 9 to 17, characterized by a washing apparatus (19) arranged downstream of the water cutter (2) to wash a mixture of comminuted biomass (2) and liquid (20). Device according to Claim 18, characterized in that the washing apparatus (19) is a container (21), in which solids (22a, b) not provided for energy recovery can be separated out in the flotation/precipitation process. Device according to Claim 18 or 19, in which the liquid content of the mixture of comminuted biomass (1) and liquid (20) in the washing apparatus (19) can be determined by means of a measuring apparatus (23), and can be corrected to a defined extent by means of a liquid feed and/or liquid discharge apparatus (24). Device according to one of Claims 17 to 20, in which the temperature of the mixture of biomass (1) and liquid (20) can be determined by means of temperature sensors (25) and corrected to a defined extent by means of a heating and/or cooling apparatus (26). Device according to one of Claims 18 to 21, characterized by an apparatus (27), connected downstream of the water cutter (2) or the washing apparatus (19), for separating and collecting the liquid (20) from the mixture of comminuted biomass (2) and liquid (20). Device according to Claim 22, characterized in that the apparatus (27) for separating and collecting the liquid has a press, centrifuge or a similar highly effective apparatus (28) for mechanically drying the biomass (1). Device according to one of Claims 18 to 23, characterized by a supply line (29), by means of which the liquid (20) required for the operation of the water cutter (2) can be taken from the washing apparatus (19) or the apparatus (27) for separating and collecting the liquid and fed to the water cutter (2). Device according to Claim 24, characterized by an apparatus by means of which the liquid (20) to be fed back into the water cutter (2) can be cleaned and temperature-controlled or have its temperature readjusted.
02/26/2013 00:00:00
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2.1.26 Centrifugation
Method for preparing fermentable sugar from wood-based biomass

1. A method for preparing fermentable sugar from lignocellulosic biomass for use in fermentation of industrial microorganisms, consisting of the steps of: 1) adding water to coarsely ground or powder lignocellulosic biomass having an average particle diameter of 0.1 mm to 50 mm or powdered lignocellulosic biomass to produce a first mixture, heating the mixture at 95 to 140° C. for 1 to 60 minutes, and then dewatering the mixture before the first mixture cools down to produce a first solid residue; 2) adding water to the solid residue obtained in step 1), and subjecting the mixture to autohydrolysis pretreatment at 170 to 210° C. for 1 to 30 minutes; 3) subjecting the autohydrolyzed material obtained in step 2) to solid-liquid separation to obtain a solid residue containing an amount of 5 to 30 wt % based on the total amount of the liquid part of the autohydrolyzed material produces in the pretreatment process; 4) subjecting the solid residue obtained in step 3) to enzymatic saccharification at a temperature of 45 to 55° C. using a cellulase complex enzyme; 5) repeating solid-liquid separation and extraction using the saccharified material obtained in step 4) to obtain a sugar solution; and 6) subjecting the sugar solution obtained in step 5) to filtration, concentration and then impurity removal. 2. The method of claim 1 , wherein the weight ratio of the coarsely ground or powder lignocellulosic biomass having an average particle diameter of 0.1 mm to 50 mm or powdered lignocellulosic biomass to water in step 1) is in a range of 1:4 to 1:20. 3. The method of claim 1 , wherein the solid-liquid separation in step 3) is carried out by centrifugation, suction filtration or pressure filtration. 4. The method of claim 1 , wherein the recovery of the sugar solution of step 5) is carried out by batch type or continuous centrifugation, filter press or screw press. 5. The method of claim 1 , wherein the filtration, concentration and impurity removal of the sugar solution in step 6) are carried out by a membrane separation technique using a reverse osmosis membrane. 6. The method of claim 1 , wherein the fermentable sugar obtained in step 6) contains glucose in an amount of at least 30%.
12/26/2013 00:00:00
Link to Patent
2.1.27 Centrifugation
Methods for mechanically dewatering peat
Although the invention has been described in connection with a preferred embodiment thereof, it will be appreciated by those skilled in the art that additions, modifications, substitutions and deletions not specifically described may be made without departing from the spirit and scope of the invention as defined in the appended claims.
1. A process for dewatering peat, said process utilizing a decanter centrifuge and a mechanical press, said process comprising the steps of: subjecting a slurry of water and fibrous peat to centrifugal forces in the decanter centrifuge to separate from said water/peat slurry an effluent of water and fine peat particles, recovering said water/peat slurry absent said separated effluent, and thereafter mechanically pressing the recovered water/peat slurry in the press to express water from the recovered water/peat slurry, at least a substantial portion of which water being expressed in liquid form. 2. A process according to claim 1, wherein said recovered water/peat slurry is mechanically pressed until the slurry contains from 40-65% dry substance by weight. 3. A process according to claim 1, wherein said fine peat particles contained in said effluent constitute at least 10% by weight of the dry substance originally present in the slurry. 4. A process according to claim 1, wherein said recovered water/peat slurry contains from 10% to 35% dry substance by weight.
11/21/1978 00:00:00
Link to Patent
2.1.28 Centrifugation
Methods of enhancing fine particle dewatering

1. A process for dewatering a slurry of hydrophobic coal particulate material comprising:i) forming a layer of hydrophobes on the surface of said hydrophobic coal particulate material and initially increasing the hydrophobicity of said hydrophobic coal particulate material by adding hydrocarbon oil to said slurry, wherein the hydrophobicity of said coal particulate material is increased;ii) adding a nonionic surfactant of hydrophile-lipophile balance (HLB) number less than 15 dissolved in at least one organic solvent;iii) allowing said nonionic surfactant to adsorb on less hydrophobic parts of the surface of said hydrophobic coal particulate material to further increase hydrophobicity of said hydrophobic coal particulate material having increased hydrophobicity from the addition of said hydrocarbon oil; andiv) effecting separation of water from said slurry of hydrophobic coal particulate material by subjecting said slurry to a mechanical method of dewatering. 2. The process of claim 1, further comprising agitating said slurry. 3. The process of claim 1, wherein said particulate material comprises particles of less than 2 mm in size. 4. The process of claim 1, wherein said nonionic surfactant is selected from the group consisting of: fatty acids, fatty esters, phosphate esters, hydrophobic polymers, ethers, glycol derivatives, sarcosine derivatives, silicon-based surfactants and polymers, sorbitan derivatives, sucrose and glucose esters and derivatives, lanolin-based derivatives, glycerol esters, ethoylated fatty esters, ethoxylated amines and amides, ethoxylated linear alcohols, ethoxylated tryglycerides, ethoylated vegetable oils, and ethoxylated fatty acids. 5. The process of claim 1, wherein said nonionic surfactant is dissolved in an oil of vegetable origin. 6. The process of claim 1, wherein said organic solvent includes a solvent selected from the group consisting of: light hydrocarbon oils and short-chain alcohols. 7. The process of claim 6, wherein said light hydrocarbon oils are selected from diesel oil, kerosene, gasoline, petroleum distillate, turpentine, naphtanic oils, and oils of vegetable origins. 8. The process of claim 6, wherein said short-chain alcohols have carbon atom numbers less than eight. 9. The process of claim 1, wherein said mechanical method of dewatering is selected from the group consisting of: vacuum filtration, pressure filtration, centrifugal filtration, and centrifugation. 10. A process for dewatering a slurry of hydrophobic coal particulate material comprising:forming a layer of hydrophobes on the surface of said hydrophobic coal particulate material and initially increasing the hydrophobicity of said hydrophobic coal particulate material by adding hydrocarbon oil to said slurry, wherein said hydrophobic coal particulate material exhibits a contact angle and the contact angle of said hydrophobic coal particulate material is below 45°;dissolving a nonionic surfactant of hydrophile-lipophile balance (HLB) number less than 15 in at least one organic solvent;adding said dissolved nonionic surfactant and said at least one organic solvent to said slurry; andallowing said nonionic surfactant to adsorb on less hydrophobic parts of the surface of said hydrophobic coal particulate material, to further increase the hydrophobicity of said material having increased hydrophobicity from the addition of said hydrocarbon oil, wherein said contact angle of said hydrophobic coal particulate material is above 45°; andeffecting separation of water from said slurry of hydrophobic coal particulate material by subjecting said slurry to a mechanical method of dewatering. 11. The process according to claim 10, further comprising agitating said slurry. 12. The process of claim 10, wherein said organic solvent includes a solvent selected from the group consisting of: light hydrocarbon oils and short-chain alcohols. 13. The process of claim 12, wherein said light hydrocarbon oils are selected from diesel oil, kerosene, gasoline, petroleum distillate, turpentine, naphtanic oils, and oils of vegetable origins. 14. The process of claim 12, wherein said short-chain alcohols have carbon atom numbers less than eight. 15. The process of claim 10, wherein said coal particulate material comprises particles of less than 2 mm in size. 16. A process for dewatering a slurry of superficially oxidized coal particles, comprising:i) initially regenerating the hydrophobic surface of said oxidized coal particles,ii) forming a layer of hydrophobes on the surface of said hydrophobic coal particulate material and increasing the hydrophobicity of said coal particles by adding hydrocarbon oil to said slurry,ii) adding a non-ionic surfactant of hydrophile-lipophile balance (HLB) number less than 15 dissolved in at least on organic solvent;iii) allowing said non-ionic surfactant to adsorb on less hydrophobic parts of the surface of said coal particles, to further increase the hydrophobicity of said coal particles having increased hydrophobicity from the addition of said hydrocarbon oil; andiv) effecting separation of water from said slurry of hydrophobic particulate material by subjecting said slurry to a mechanical method of dewatering. 17. The process of claim 16, wherein said superficially oxidized coal particles are wet ground in a ball mill to regenerate the hydrophobic surface.
08/03/2007 00:00:00
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2.1.29 Centrifugation
Methods of using natural products as dewatering aids for fine particles
A method of dewatering fine particulate materials is disclosed. In this method, an aqueous slurry of fine particles is treated with appropriate hydrophobizing reagents so that the particulate material becomes moderately hydrophobic. A lipid of vegetable or animal origin is then added to the slurry in solutions of light hydrocarbon oils and short-chain alcohols, so that the hydrophobic lipid molecules adsorb on the moderately hydrophobic surface and, thereby, greatly enhance its hydrophobicity. By virtue of the enhanced hydrophobicty, the water molecules adhering to the surface are destabilized and more readily removed during the process of mechanical dewatering. The moisture reduction can be further improved using appropriate electrolytes in conjunction with the lipids, spraying surface tension lowering reagents onto the filter cake, subjecting the cake to a suitable vibratory means, and using combinations thereof.
1. A process for dewatering a slurry of fine particulate material comprising: i) rendering the material hydrophobic, ii) adding lipids dissolved in organic solvent, iii) agitating the slurry to allow for the lipid molecules to adsorb on the surface of the hydrophobized material so that its hydrophobicity is increased, and iv) subjecting the slurry containing the particulate material, whose water contact angle has now been increased, to a mechanical method of dewatering, so that the moisture of the particulate material is reduced. 2. The process of claim 1 wherein the fine particulate material is smaller than 2 mm in diameter. 3. The process of claim 1 wherein the initial hydrophobization is achieved using surfactants and collectors. 4. The process of claim 3 wherein the surfactants are high HBL surfactants, whose polar heads can interact with the surface of the particulate materials. 5. The process of claim 3 wherein the collectors are thiols for sulfide minerals and metals. 6. The process of claim 3 wherein the collectors are hydrocarbon oils when the particulate material is coal and other non-polar substances. 7. The process of claim 1 wherein the initial hydrophobization step is omitted when the particulate material is non-polar. 8. The process of claim 1 wherein the initial hydrophobization step involves creating fresh surfaces by comminution, when the particulate material to be dewatered is non-polar. 9. The process of claim 1 wherein the initial hydrophobization step is employed when the surface of the particulate material to be dewatered has become less hydrophobic due to superficial oxidation. 10. The process of claim 1 wherein the initial hydrophobization step renders the surface of the particulate material hydrophobic so that its water contact angle is less than 90°. 11. The process of claim 1 wherein said mechanical means is filtration. 12. The process of claim 1 wherein the lipid are of vegetable origin. 13. The process of claim 1 wherein a hydrophobicity-enhancing reagent disclosed in claim 10 is blended with a nonionic surfactant of hydophile- lipophile balance number of less than 15. 14. The process of claim 1 wherein the solvent is selected from light hydrocarbon oils of less than eight carbons, short-chain alcohols, and ethers. 15. The process of claim 1 wherein the initial hydrophobization step is omitted when the particulate material has become hydrophobic in an upstream process. 16. The process of claim 15 wherein the upstream processes is conditioning, in which surfactants and collectors, including those that are used for flotation, are contacted with the particulate material. 17. The process of claim 15 wherein the upstream process is floatation. 18. The process of claim 1 wherein the mechanical method is performed by centrifugation. 19. The process of claim 1 wherein the lipid is of animal origin including fish. 20. A process for dewatering a slurry of fine particulate material comprising: i) rendering the material hydrophobic, ii) adding an inorganic electrolyte, iii) adding a lipid dissolved in an organic solvent, iv) agitating the slurry to allow for the lipid molecules to adsorb on the surface of the hydrophobized particulate material so that its hydrophobicity is increased, and v) subjecting the slurry containing the particles, whose water contact angle has now been increased, to a mechanical method of dewatering, so that the amount of the lipids required to achieve a requisite moisture content of the particulate material is reduced. 21. The process of claim 20 wherein the inorganic electrolytes is selected from salts of monovalent, divalent and trivalent cations and anions. 22. The process of claim 20 wherein the electrolytes are the salts of aluminum ions. 23. The process of claim 20 wherein the fine particulate material is smaller than 2 mm in diameter. 24. The process of claim 20 wherein the initial hydrophobizing step is achieved using surfactants and collectors, including those that are used for floatation. 25. The process of claim 20 wherein the lipid is selected from those of vegetable and animal origins including fish. 26. The process of claim 20 wherein the initial hydrophobization step is omitted when the particulate material is non-polar. 27. The process of claim 20 wherein the initial hydrophobization step is omitted when the particulate material has become hydrophobic in an upstream process. 28. The process of claim 20 wherein the solvent is selected from light hydrocarbon oils of less than eight carbons, short-chain alcohols and ethers. 29. A process for dewatering a slurry of fine particulate material comprising: i) rendering the material hydrophobic, ii) adding a lipid in organic solvent, iii) agitating the slurry to allow for the lipid molecules to adsorb on the surface of the hydrophobized particulate material so that its hydrophobicity is enhanced, and iv) subjecting the conditioned slurry containing the particulate material, whose water contact angle has now been increased, to a vibratory means, so that an increased moisture reduction is achieved at a given cake thickness. 30. The process of claim 29 wherein said vibratory means is selected from ultrasonic, mechanical and acoustic means. 31. The process of claim 29 wherein the particle sizes are smaller than 2 mm. 32. The process of claim 29 wherein the initial hydrophobization is achieved using surfactants and collectors, including those that are used for floatation. 33. The process of claim 29 wherein said lipid is selected from those of vegetable and animal origins. 34. The process of claim 29 wherein the initial hydrophobization step is omitted when the particulate material is non-polar. 35. The process of claim 29 wherein the initial hydrophobization step is omitted when the particulate material has become hydrophobic in an upstream process. 36. The process of claim 29 wherein the solvent is selected from light hydrocarbon oils of less than eight carbons, short-chain alcohols and ethers. 37. A process for dewatering a slurry of fine particulate material comprising: i) rendering the material hydrophobic, ii) adding a lipid dissolved in organic solvent, iii) agitating the slurry to allow for the lipid molecules to adsorb on the surface of the hydrophobized particulate material so that its hydrophobicity is increased, and iv) subjecting the conditioned slurry containing the particulate material, whose water contact angle has now been increased, to a filtration process in which a surface tension lowering reagent is added to the filter cake in the form of fine spray, so that an increased moisture reduction is achieved at a given cake thickness. 38. The process of claim 37 wherein the suitable surface tension lowering agent is selected from short-chain alcohols, light hydrocarbon oils of less than eight carbons, and appropriate surfactants. 39. The process of claim 37 wherein the particle sizes are less than 2 mm. 40. The process of claim 37 wherein the initial hydrophobization step is achieved using surfactants and collectors, including those that are used for floatation. 41. The process of claim 37 wherein said lipid is selected from those of vegetable and animal origins. 42. The process of claim 37 wherein the initial hydrophobization step is omitted when the particulate material is non-polar. 43. The process of claim 37 wherein the initial hydrophobization step is omitted when the particulate material has become hydrophobic in an upstream process. 44. The process of claim 37 wherein the solvent is selected from light hydrocarbon oils of less than eight carbons, short-chain alcohols aid ethers. 45. A process for dewatering a slurry of fine particulate material comprising: i) rendering the material hydrophobic, ii) adding an inorganic electrolyte to the slurry, iii) adding a lipid dissolved in an organic solvent, iv) agitating the slurry to allow for the lipid molecules to adsorb on the surface of the hydrophobized particulate material so that its hydrophobicity is increased, and v) subjecting the conditioned slurry containing the particulate material, whose water contact angle has now been increased, to a filtration process in which a surface tension lowering reagent is added to the filter cake in the form of fine spray while the filter cake is subjected to a vibratory means, so that an increased moisture reduction is achieved using less reagents. 46. The process of claim 45 wherein the range of particle sizes is less than 2 mm. 47. The process of claim 45 wherein the initial hydrophobization is achieved using surfactants and collectors including those that are used for floatation. 48. The process of claim 45 wherein said lipid is selected from those of vegetable and animal origins. 49. The process of claim 45 wherein the initial hydrophobization step is omitted when the particulate material is non-polar. 50. The process of claim 45 wherein the initial hydrophobization step is omitted when the particulate material has become hydrophobic in an upstream process. 51. The process of claim 45 wherein the solvent is selected from light hydrocarbon oils of less than eight carbons, short chain alcohols and ethers.
06/07/1999 00:00:00
Link to Patent
2.1.30 Centrifugation
Process for dewatering microfibrillated cellulose

1. A process for dewatering a slurry comprising a microfibrillated cellulose by only subjecting the slurry to a mechanical pressure, without significant hornification of the microfibrillated cellulose, wherein the process comprises the following steps: providing a slurry comprising a microfibrillated cellulose and a liquid, subjecting the slurry to a first mechanical pressure in order to dewater the slurry, and subjecting the slurry to a second mechanical pressure which second pressure is higher than the first pressure. 2. The process according to claim 1 wherein the process further comprises the step of subjecting the slurry to a third mechanical pressure which third pressure is higher than the second pressure. 3. The process according to claim 1 , wherein the slurry is conducted between two wires before the slurry is subjected to the first mechanical pressure. 4. The process according to claim 1 , wherein the slurry is subjected to the first and second mechanical pressure by conducting the slurry through a wedge gap. 5. The process according to claim 1 , wherein the slurry is subjected to the first and second pressure by conducting the slurry over a roll having a first roll diameter. 6. The process according to claim 5 wherein the slurry is subjected to the second mechanical pressure by conducting the slurry over a roll having a second roll diameter said second roll diameter being smaller than the first roll diameter. 7. The process according to claim 6 wherein the slurry is conducted over more than one roll having a second roll diameter. 8. The process according to claim 1 , wherein the slurry is subjected to the first and second mechanical pressure by conducting the slurry to a decanter- centrifuge. 9. The process according to claim 1 , wherein the slurry is subjected to the second mechanical pressure by conducting the slurry to a screw press. 10. The process according to claim 1 , wherein the dry content of the slurry comprising a microfibrillated cellulose before the dewatering is 0.1-10% by weight. 11. The process according to claim 1 , wherein the dry content of the dewatered slurry comprising a microfibrillated cellulose is 1-50% by weight.
11/05/2014 00:00:00
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3. Electrokinetics

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Electrohydrodynamics (EHD), also known as electro-fluid-dynamics (EFD) or electrokinetics, is the study of the dynamics of electrically charged fluids. [\[link\]](https://en.wikipedia.org/wiki/Electrohydrodynamics)


3.1 Electro-dewatering

0

Electrodewatering is a technique in which pressure dewatering is combined with electrokinetic effects to realize an improved solid/liquid separation and hence increased filter cake dry matter contents.[ \[Art. #ARTNUM\]](#article-96006-2005699518) Enhanced electrokinetic dewatering techniques include systems based on electroosmosis, electromigration and electrophoresis principles. [\[link\]](https://scholar.google.com/scholar?as_sdt=0%2C5&btnG=&hl=en&inst=4393003693960974403&q=Harvesting%2C%20Thickening%20and%20Dewatering%20Microalgae%20Biomass) **Note:** in final results [Electrocoagulation + electro-dewatering ](#technology-96327)is included here. **Highlights:** * **Electro-dewatering (EDW)** is an alternative emerging and **energy-efficient technology** that provides improved liquid/solids separations in the dewatering of wastewater sludge. The EDW technology is not only an innovative dewatering method for significantly reducing the volume of wastewater sludge before re-utilization or disposal, but is also a promising emerging method which may potentially be used for **decontamination** purposes. In this study, the influence of the sludge properties (e.g. electrical conductivity, zeta potential, specific cake resistance, among others) on their mechanical and electrical behaviour in terms of dewaterability and electro-dewaterability, the applied current (current density from 20 to 80 A/m 2 ), and filter cloth position relative to the electrode was investigated.[ \[Art. #ARTNUM\]](#article-96006-2767856657) * The **pressure-driven electro-dewatering (EDW)** of sewage sludge was assessed using a lab device. \[...\] The test results show that the EDW treatment enabled to dewater the sludge samples to a **dry solids content of** **18.4–31.1%** (wt%), which means 2.0–12.7% improvement as compared to the conventional mechanical dewatering treatment used in these WWTPs. A follow-up test was carried out with the sample giving the best dewatering performance. A **dry solids content of 39.3% (wt%)** was achieved. \[...\] The **energy consumption** and sludge treatment cost associated with the EDW process were compared with the reference case (the corresponding WWTP currently operating with mechanical dewatering line). It was found that for the best performance case, technology upgrade from the conventional mechanical dewatering to the EDW dewatering will enable the WWTP to **reduce** its sludge management **cost up to 35% per year**.[ \[Art. #ARTNUM\]](#article-96006-2767836018) * In this work, a device and a process for dewatering offshore grown biomass of the green **macroalgae** Ulva sp. using high-voltage **pulsed electric fields (PEF)** was developed. Ulva sp. was cultivated attached to fish cages 15km offshore. Increasing the applied voltage from 250V to 500V and invested PEF energy from 9.3±0.4 J g-1FW to 54.6±0.2Jg-1FW **increased the extracted water** from 0.033±0.006gWater g-1FW to 0.150±0.031gWater g-1FW. \[...\] PEF leads to biomass compression of 8.45±1.72% for 250V protocol and 25.66±2.53% for 500V protocol. In addition, PEF leads to the reduction of water diffusivity of 18-19% in the treated biomass, reducing air drying kinetics. [\[Art. #ARTNUM\]](#article-96006-2978757633) * Electrokinetic geocomposites (eGCPs) installed into the **FFT** \[fluid fine tailings\] disposal area may improve in situ dewatering, as eGCPs can drain water expulsed during FFT consolidation as well as impose a voltage across FFT to displace water by electro-osmosis. This paper presents a laboratory device specifically developed to evaluate eGCP performance for sludge dewatering. \[...\] the **solids content was increased from 42% to 66%**, which led to a significant improvement of the shear strength from nearly 0 kPa to a mean value of 40 kPa. The energy required for this experiment was **71 W·h (3.5 kW·h/(m3 of sludge)).** [\[Art. #ARTNUM\]](#article-96006-1968853056) * Capacitive electrokinetic densification, decontamination and dewatering of suspensions and soils can be performed while controlling and/or preventing chemical and pH changes in the densified material and extracted water. High electrical capacitance electrodes or **Electric Double Layer Capacitor (EDLC) electrodes** are used \[...\] suspension to be treated is selected from the group consisting of oil sands tailings, clay-water suspensions such as Mature Fine Tailings (MFT), dispersions or suspensions of inorganic particles that are a by-product of mining, manufacturing or other industrial processes, food and food processing waste suspensions, biological wastes, and biomass sludges.[ \[Art. #ARTNUM\]](#article-96006-US20190015785A1) * Patent Ionic Solutions * Process for sulphur removal, by using dewatering, of a slurry comprising a lignin \[...\] the dewatering is done by electro-osmosis \[...\] dry content of the slurry comprising lignin, before dewatering, is 1-50% by weight.[ \[Art. #ARTNUM\]](#article-96006-EP3200902B1) * Patent Stora Enso * An **adaptive electrokinetic dewatering system** for dewatering slurry and soil deposits, including **tailings** deposits and a control system therefor. The control system automatically determines an **optimal applied power specification**, including sets of power parameters to be applied to the deposit being dewatered and when to apply each set of power parameters during the electrokinetic dewatering process.[ \[Art. #ARTNUM\]](#article-96006-US20190241453A1) * Patent Electro-kinetic solutions Inc. **Electro-dewatering + Electrocoagulation:** * Electrocoagulation is applied to sewage sludge as a pretreatment process of an electrodewatering system to reduce the water content of sludge generated in wastewater treatment. \[...\] The final **water content** of sewage sludge in the combination of both electrocoagulation and electrodewatering system can be **reduced to 55 wt%**, as compared to 78 wt% achieved with pressure dewatering alone. The combination of electrocoagulation and electrodewatering system shows a potential to be an effective method for reducing the water content in sludge. [\[Art. #ARTNUM\]](#article-96327-2058170914) * The invention relates to a combined method of treatment of sludge involving firstly treatment with electroosmosis of a slurry for dewatering the sludge, thereby generating at least one effluent, and on the other hand treatment of this effluent by **electrocoagulation or electroflotation**. [\[Art. #ARTNUM\]](#article-96006-2605341858) * Patent GL&V Canada * GLV acquired Elcotech Technologies. Elcotech developed an electro-osmosis to separate water from bio-solids. [\[web\]](https://www.sciencedirect.com/science/article/pii/S0958211809701259) **Other combinations:** * Gravity-thickened sludge (GTS) and anaerobically-digested sludge (ADS) from a wastewater treatment plant and sludge from drying bed (DBS) from a water treatment plant were dewatered using the pilot-scale **electro-osmotic belt filter press (EBFP)**. The results indicated that the **addition of electro-osmosis** greatly **improved sludge dewaterability,** lowering water content (WC) and heavy metal concentration, and increasing heating value. \[...\] Therefore, EBFP would produce a proper cake WC by simply controlling the current density, depending on the destination of dewatered cake such as **land application, compost, or incineration.**[ \[Art. #ARTNUM\]](#article-96006-1801256887) * \[...\] a bench- and pilot-scale diaphragm **filter press suited for electrodewatering** were constructed for treatment of sewage and other types of sludges. It was shown that **electrodewatering of sludge is a feasible technique**, especially for **biological sludge** types. Other types of sludge are less suited for electrodewatering because of the restricted improvements that can be realized in cake dry matter content and the high electric energy consumption. Furthermore, it was shown in pilot-scale tests that the use of a diaphragm filter press with electrodewatering facilities was very well suited to deliver dry filter cakes of sewage sludge at a **moderate energy consumption**. [\[Art. #ARTNUM\]](#article-96006-2005699518) * This paper presents results of experimental work carried out to study and analyze the combined operation of electro-osmotic dewatering (EOD) and **mechanical expression (ME)** \[...\] The large water content of **bentonite slurry** can be reduced well by the EOD-ME combined operation.[ \[Art. #ARTNUM\]](#article-96006-8173466) * Full-scale electrokinetic facilities were developed that were based on a combination of a **gravity-driven thickening belt and a belt press.** The method was tested at a drinking water production site. By the use of the electrokinetic facility when drying **‘aluminum-coagulated’ drinking water sludge** (i.e. coagulated by the addition of Al-ions), the dry solids content increased by electro-osmosis from 17 to 24% m/m at an additional energy consumption level of 60 kWh per ton dry soldids. Supplementary laboratory experiments suggest that electrokinetic dewatering is also useful in dewatering **‘iron-coagulated’ drinking water sludge, sewage treatment sludge and fresh water dredging sludge.**[ \[Art. #ARTNUM\]](#article-96006-2125732985) **Combined with treatments:** * The results indicate near-anode sludge modification with CaO weighing 3%–5% mass of raw sludge ( m u ( R S ) ) improved the EDW effect, while the energy consumption increased slightly. When 3%–5% m u ( R S ) of **CaO** was added, the **final moisture content of sludge was 54.5%–44.3%**, below that of the blank group (no CaO added), which was 57.9%; the time to obtain target moisture content (60%) was 910 s–590 s, lower than the blank group's 1060 s; and the energy consumption to obtain target moisture content was **0.233 kW h/kg H2O–0.271 kW h/kg H2O**, higher than the blank group's **0.157 kW h/kg H2O**. A quantitative criterion ( K s i E D W ) was adopted to assess the feasibility of EDW. Economically and energetically, the experiment with **4% m u ( R S ) of CaO** added for near-anode modification was the **optimal condition** in this research, due to its second smallest K s i E D W , the best sludge reduction effect (67.2%), lower final moisture content (46.2%) and less time (640 s) to obtain target moisture content. [\[Art. #ARTNUM\]](#article-96006-3015450387) * The feasibility of electrolysis integrated with **Fe(II)-activated persulfate ( S 2 O 8 2 - ) oxidation** to improve waste activated sludge (WAS) dewaterability was evaluated. \[...\] electrolysis integrated with S 2 O 8 2 - /Fe(II) oxidation was able to effectively disrupt the protective barrier and crack the entrapped cells, **releasing the water inside EPS and cells**.[ \[Art. #ARTNUM\]](#article-96006-1980826537) * We investigated the change in sludge dewaterability after the addition of **fly ash** to municipal digested sludge, dewatering of which is difficult because of its high organic content. The performance of the dewatering is compared with that of **electroosmotic dewatering (EDW)** and conventional mechanical dewatering (CMD). \[...\] When sludge was dewatered using an electroosmotic dewatering method, the dewatering efficiency is improved about **40%** by **adding fly ash** of 25–75 μm particle size with 20 wt% when compared with conventional mechanical dewatering method without adding the fly ash. [\[Art. #ARTNUM\]](#article-96006-2071674155) * In waste treatment process, decreasing of water load from the coal sludge is economical and feasible before disposal. Electroosmosis dewatering (EOD) is **more energy saving and effective process** over other conventional dewatering process. \[...\] This experiment was done by dewatering fine coal sludge using two copper disks as electrodes. \[...\] The moisture content of the slurry is measured at **5% NaOH** for 100V is around **19.7%** which is approximately 6% lower than as compared to without using caustic solution under same operating condition \[...\] The energy used for the removal of above moisture content (19.7%) is around **5KWh/Kg** of dewater, which is 54% less than the thermal processing of sludge.[ \[Art. #ARTNUM\]](#article-96006-2343125410)

3.1.1 Electro-dewatering
A comparative study of electro-dewatering process performance for activated and digested wastewater sludge
Abstract Electro-dewatering (EDW) is an alternative emerging and energy-efficient technology that provides improved liquid/solids separations in the dewatering of wastewater sludge. The EDW technology is not only an innovative dewatering method for significantly reducing the volume of wastewater sludge before re-utilization or disposal, but is also a promising emerging method which may potentially be used for decontamination purposes. In this study, the influence of the sludge properties (e.g. electrical conductivity, zeta potential, specific cake resistance, among others) on their mechanical and electrical behaviour in terms of dewaterability and electro-dewaterability, the applied current (current density from 20 to 80 A/m 2 ), and filter cloth position relative to the electrode was investigated. A two-sided filter press at lab-scale with moving anode was used, and the treatment performance of the EDW process on two different types of wastewater sludge (activated and digested) was thoroughly assessed from both an electrochemical viewpoint and in terms of the dewatering rate. The results showed that the conditioned digested sludge was more easily dewatered by mechanical dewatering (MDW) with 34–35% (w%) of dry solids content compared to 19–20% (w%) for the activated sludge, thanks to the lower content of both the microbial extracellular polymeric substances (EPS) and the volatile suspended solids fraction. For the EDW results, the electrical conductivity of the sludge was pivotal to the dryness of the final solids and therefore also to the dewatering kinetics. The results demonstrated that the activated sludge arrived at an equilibrium much faster (after approximately 3600 s) compared with digested sludge, thanks to its lower electrical conductivity (0.8 mS/cm) providing a greater voltage drop across the cathode and therefore more repulsion of the solids from the cathode leading to continuously high filtrate flowrate. Also the EDW performance was analysed by comparing the ratio of the filtrate volume collected at the anode to the volume collected at the cathode side. For digested sludge at 5 bar, 40 A/m 2 different positions of the filter cloth were tested but these configurations barely impacted the EDW performance, despite having a significant impact on the energy requirements. At industrial scale, it would be useful to position the filter cloths at some distance from the electrodes, but this study shows that this benefit may be quickly outweighed by the loss in EDW energy efficiency.
02/01/2018 00:00:00
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3.1.2 Electro-dewatering
Analysis of combined operation of electro-osmetic dewatering and mechanical expression
This paper presents results of experimental work carried out to study and analyze the combined operation of electro-osmotic dewatering (EOD) and mechanical expression (ME) by use of the Terzaghi-Voigt combined model for considering creep deformation of the material. The EOD-ME process combines the advantage of electro-osmosis and mechanical dewatering, resulting in reduced void ratio compared to individual operation. The basic differential equation based on the model is solved analytically by assuming that both an electro-osmotic pressure gradient Epg and a modified consolidation coefficient Ce of the material are constant, resulting in the equation of solid compressive pressure in the material as a function of time and position. The analysis also leads to the equation of the average consolidation ratio Uc, which is a measure of the progress of dewatering; this equation can describe well the empirical results under various conditions. The large water content ofbentonite slurry can be reduced well by the EOD-ME combined operation.
01/01/2009 00:00:00
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3.1.3 Electro-dewatering
Assessment of pressure-driven electro-dewatering as a single-stage treatment for stabilized sewage sludge
Abstract The pressure-driven electro-dewatering (EDW) of sewage sludge was assessed using a lab device. The sludge samples were supplied from four different Wastewater Treatment Plants (WWTPs) around the metropolitan area of Milan (Italy), including both aerobically and anaerobically stabilised samples. The test results show that the EDW treatment enabled to dewater the sludge samples to a dry solids content of 18.4–31.1% (wt%), which means 2.0–12.7% improvement as compared to the conventional mechanical dewatering treatment used in these WWTPs. A follow-up test was carried out with the sample giving the best dewatering performance. A dry solids content of 39.3% (wt%) was achieved. Apart from the technological performance, the economic feasibility of EDW was evaluated. The energy consumption and sludge treatment cost associated with the EDW process were compared with the reference case (the corresponding WWTP currently operating with mechanical dewatering line). It was found that for the best performance case, technology upgrade from the conventional mechanical dewatering to the EDW dewatering will enable the WWTP to reduce its sludge management cost up to 35% per year.
12/01/2017 00:00:00
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3.1.4 Electro-dewatering
Bench- and pilot-scale sludge electrodewatering in a diaphragm filter press
Electrodewatering is a technique in which pressure dewatering is combined with electrokinetic effects to realize an improved solid/liquid separation and hence increased filter cake dry matter contents. In order to be energy efficient, it is shown that sludge should be dewatered by pressure dewatering to a high extent prior to electric field application, and a sufficient contact time for the electric field must be guaranteed. In order to realize these goals, a bench- and pilot-scale diaphragm filter press suited for electrodewatering were constructed for treatment of sewage and other types of sludges. It was shown that electrodewatering of sludge is a feasible technique, especially for biological sludge types. Other types of sludge are less suited for electrodewatering because of the restricted improvements that can be realized in cake dry matter content and the high electric energy consumption. Furthermore, it was shown in pilot-scale tests that the use of a diaphragm filter press with electrodewatering facilities was very well suited to deliver dry filter cakes of sewage sludge at a moderate energy consumption. Depending on local market prices for investment, operating and sludge disposal costs, this technology may therefore lead to important savings in the sludge management process.
08/01/2006 00:00:00
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3.1.5 Electro-dewatering
Dewatering of drinking water treatment sludge by vacuum electro-osmosis
ABSTRACTThe objective of this research was to evaluate the dewatering of drinking water treatment sludge (DWTS) by vacuum electro-osmosis dewatering (VEOD) technology. DWTS has a high moisture content, with the water existing as free water, pore water, surface adhesion water and internal combined water. Vacuum filtration of 0.05 MPa can quickly dewater sludge and has low energy consumption, but can only remove free water and some pore water. The moisture content of the DWTS was reduced to below 79% by vacuum filtration technique alone. At this moisture content, all free water had been expelled by vacuum filtration. Electro-osmosis optimized for the experimental conditions (0.05 MPa, 2.5 V/cm) began after vacuum filtration ceased, and drew pore water and surface adhesion water to the cathode, where it was expelled through vacuum filtration. The VEOD process removed all free water. In addition, pore water and surface adhesion water were reduced by 60.2% and 15.9%, respectively.
09/01/2016 00:00:00
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3.1.6 Electro-dewatering
Electro-dewatering of sewage sludge: Effect of near-anode sludge modification with different dosages of calcium oxide
Abstract The efficiency of common sludge electro-dewatering (EDW) is restrained by the following issues: 1, the near-anode sludge dries out quickly, causing a rapid increase in electrical resistance; 2, the pH at anode decreases by the accumulation of H+ from the electrolysis of moisture, resulting in a decrease in Zeta potential ( ζ ). Alleviating the negative impact of these problems is the key to improving the dewatering efficiency of EDW. Therefore, in this study, calcium oxide (CaO) was used for near-anode sludge modification to increase its pH and electrical conductivity. With increasing CaO dosage, pH rose from 6.0 to 12.2, electrical conductivity increased from 368 ± 16 μS/cm to 6285 ± 21 μS/cm and the ζ declined from −15.3 ± 0.6 mV to −8.8 ± 0.4 mV. The EDW tests were conducted at 30 V and 25.5 kPa. The results indicate near-anode sludge modification with CaO weighing 3%–5% mass of raw sludge ( m u ( R S ) ) improved the EDW effect, while the energy consumption increased slightly. When 3%–5% m u ( R S ) of CaO was added, the final moisture content of sludge was 54.5%–44.3%, below that of the blank group (no CaO added), which was 57.9%; the time to obtain target moisture content (60%) was 910 s–590 s, lower than the blank group's 1060 s; and the energy consumption to obtain target moisture content was 0.233 kW h/kg H2O–0.271 kW h/kg H2O, higher than the blank group's 0.157 kW h/kg H2O. A quantitative criterion ( K s i E D W ) was adopted to assess the feasibility of EDW. Economically and energetically, the experiment with 4% m u ( R S ) of CaO added for near-anode modification was the optimal condition in this research, due to its second smallest K s i E D W , the best sludge reduction effect (67.2%), lower final moisture content (46.2%) and less time (640 s) to obtain target moisture content. The results show some mechanisms of EDW and provide experience for practical application.
04/08/2020 00:00:00
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3.1.7 Electro-dewatering
ELECTRO-OSMOSIS DEWATERING OF COAL SLUDGE
In waste treatment process, decreasing of water load from the coal sludge is economical and feasible before disposal. Electroosmosis dewatering (EOD) is more energy saving and effective process over other conventional dewatering process. Draining of water from the sludge by generating potential gradient in between two electrodes which were placed in the sludge; is called electro-osmotic dewatering process. A direct current (DC) was used to create that potential difference. This experiment was done by dewatering fine coal sludge using two copper disks as electrodes. It is reported that the flow rate of dewater is proportional to the potential difference between two electrodes and the zeta potential of the sludge particle [2] . In this study, the voltage is increased from 40V to 100V with constant current (1.1 Amp) supply. The zeta potential of the coal particle is increased by adding 1%, 2% and 5% (w/v) sodium hydroxide (NaOH) solution, respectively. The volume of water removed, % moisture content of coal slurry after EOD, volume of water evaporated from the hot electrode surface, and energy consumption are measured for each case. It is observed that as the increasing NaOH concentration and the potential difference in the slurry, the % moisture content of slurry is reduced after EOD. The moisture content of the slurry is measured at 5% NaOH for 100V is around 19.7% which is approximately 6% lower than as compared to without using caustic solution under same operating condition. The energy used for the removal of above moisture content (19.7%) is around 5KWh/Kg of dewater, which is 54% less than the thermal processing of sludge.
01/25/2016 00:00:00
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3.1.8 Electro-dewatering
ELECTRODEWATERING AND ELECTROCONCENTRATION OF CARBONACEOUS MATERIAL-WATER SLURRY, ELECTRODEWATERING APPARATUS, AND ELECTROCONCENTRATION APPARATUS
PURPOSE:To provide a process for either electrodewatering or electroconcentration of a carbonaceous material-water slurry, an electrodewatering apparatus and an electroconcentration apparatus which are capable of easily separating fine carbonaceous material particles without clogging and with a small power consumption. CONSTITUTION:In a dewatering process, a direct current is applied to a carbonaceous material- water slurry to deposit carbonaceous material particles on a positive electrode, and the deposited particles are then separated to obtain dewatered matter. In a concn. process, carbonaceous material particles are electrically concentrated near a positive electrode in the same manner as described above, and the conc. particles are then separated to obtain conc. matter. A dewatering apparatus comprises a DC power source unit 32 equipped with a positive electrode and a negative electrode for application of a direct current to a carbonaceous material- water slurry, and a separator 34 for separation of carbonaceous material particles electrically deposited on the positive electrode. A concn. apparatus comprise the same DC power source unit a mentioned above, and a separator for separation of carbonaceous material particles electrically concentrated near the positive electrode. A tank 31 for the carbonaceous material- water slurry is also used as the negative electrode. A rotator 33 as the positive electrode is disposed in such a way as to be partly immersed in the carbonaceous material-water slurry in the tank 31. A separation panel 35 is disposed in such a way as to be in contact with the rotator 33 to constitute the separator.
03/07/1995 00:00:00
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3.1.9 Electro-dewatering
Electrokinetic thickening and dewatering method and system
A method and device for using electrokinetic forces for thickening or dewatering municipal biosolids is provided. The method uses chlorine dioxide to accelerate and improve the efficiency of electrokinetic dewatering.
11/22/2016 00:00:00
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3.1.10 Electro-dewatering
Electroosmotically Enhanced Sludge Pressure Filtration.
Wastewater sludge is routinely dewatered to lower the cost of transportation and disposal. Dewatering is achieved via vacuum filtration, centrifugation, sand beds, and belt filter presses. Electroosmosis, the movement of water in the influence of a direct-current (dc) electric field, has been used since the 1930s to dewater soil for construction purposes. This study examines dewatering anaerobically and aerobically digested municipal wastewater solids with applied direct pressure and constant voltage direct current. A pressure filtration apparatus, consisting of a piston and drain plate made of conductive material encased in a body of nonconductive material, was used to apply constant pressure and constant voltage (variable current) during the experiments. Three experimental series were conducted evaluating the effect of polymer dosage and voltage on the final cake total solids ; the relationship among pressure, voltage, time, and final cake total solids ; and the relationship among initial feed solids and final cake total solids after electroosmotic filtration. Results show that final cake solids were increased to as much as 50% with 60 V dc applied. Final cake solids may be enhanced by increasing pressure, voltage, or time, and additional water may be removed from a conventionally dewatered cake by further application of dc voltage.
05/01/1999 00:00:00
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3.1.11 Electro-dewatering
Energy efficient dewatering of far offshore grown green macroalgae Ulva sp. biomass with pulsed electric fields and mechanical press
Abstract Offshore macroalgae biomass production is a promising, yet challenging, pathway to provide feedstock for biorefineries. In this work, a device and a process for dewatering offshore grown biomass of the green macroalgae Ulva sp. using high-voltage pulsed electric fields (PEF) was developed. Ulva sp. was cultivated attached to fish cages 15km offshore. Increasing the applied voltage from 250V to 500V and invested PEF energy from 9.3±0.4 J g-1FW to 54.6±0.2Jg-1FW increased the extracted water from 0.033±0.006gWater g-1FW to 0.150±0.031gWater g-1FW. The energy consumption to achieve similar moisture content with air convection drying was lower by 78.73±10.41 (JgFW-1) for 250V and 339.31±48.01 (JgFW-1) for 500V, pulse duration 50µs, pulse number 50, pulse repetition frequency 3Hz. PEF leads to biomass compression of 8.45±1.72% for 250V protocol and 25.66±2.53% for 500V protocol. In addition, PEF leads to the reduction of water diffusivity of 18-19% in the treated biomass, reducing air drying kinetics.
01/01/2020 00:00:00
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3.1.12 Electro-dewatering
Full scale electrokinetic dewatering of waste sludge
Abstract Increasing volumes of waste sludge, an intense environmental awareness and stringent legislation impose increasing demands upon conventional sludge dewatering equipment. In this study, the electrokinetic dewatering of waste slurries is studied. Full-scale electrokinetic facilities were developed that were based on a combination of a gravity-driven thickening belt and a belt press. The method was tested at a drinking water production site. By the use of the electrokinetic facility when drying ‘aluminum-coagulated’ drinking water sludge (i.e. coagulated by the addition of Al-ions), the dry solids content increased by electro-osmosis from 17 to 24% m/m at an additional energy consumption level of 60 kWh per ton dry solids. Additionally, the filter belt fouling was reduced drastically and the loss of solid particles from the cake was almost completely suppressed due to electrophoresis. Corrosion of the anode was effectively suppressed by using Ir 2 O 3 -coated titanium plates. Supplementary laboratory experiments suggest that electrokinetic dewatering is also useful in dewatering ‘iron-coagulated’ drinking water sludge, sewage treatment sludge and fresh water dredging sludge. Theoretical analyses indicate that electro-osmosis will contribute to dewatering significantly, at lower and especially at higher volume fractions of solids, provided the slurry particles are of the order of micrometers or smaller. Under such conditions the conventional dewatering is slow due to excessive hydrodynamic resistance.
11/01/2002 00:00:00
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3.1.13 Electro-dewatering
Improved sludge dewatering by addition of electro-osmosis to belt filter press
Gravity-thickened sludge (GTS) and anaerobically-digested sludge (ADS) from a wastewater treatment plant and sludge from drying bed (DBS) from a water treatment plant were dewatered using the pilot-scale electro-osmotic belt filter press (EBFP). The results indicated that the addition of electro-osmosis greatly improved sludge dewaterability, lowering water content (WC) and heavy metal concentration, and increasing heating value. For instance, EBFP produced 56.0% WC for GTS, 58.4% for ADS, and 69.6% for DBS when current density was 41.1, 42.1, and 17.9 A/m2, respectively, and a cationic coagulant was dosed at 0.36% on dried solid, 0.46%, and 0.19%, respectively. Without the addition of electricity, the system achieved only 74.3% WC for GTS, 72.8% for ADS, and 74.7% for DBS. Therefore, EBFP would produce a proper cake WC by simply controlling the current density, depending on the destination of dewatered cake such as land application, compost, or incineration. Key words: belt filter press, cake, electro-os...
03/01/2003 00:00:00
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3.1.14 Electro-dewatering
Innovative combination of electrolysis and Fe(II)-activated persulfate oxidation for improving the dewaterability of waste activated sludge
Abstract The feasibility of electrolysis integrated with Fe(II)-activated persulfate ( S 2 O 8 2 - ) oxidation to improve waste activated sludge (WAS) dewaterability was evaluated. The physicochemical properties (sludge volume (SV), total suspended solids (TSS) and volatile suspended solids (VSS)) and extracellular polymeric substances (EPS), including slime EPS, loosely bound EPS (LB-EPS) and tightly bound EPS (TB-EPS) were characterized to identify their exact roles in sludge dewatering. While dewaterability negatively corresponded to LB-EPS, TB-EPS, protein (PN) and polysaccharide (PS) in LB-EPS and TB-EPS, it was independent of SV, TSS, VSS, slime EPS and PN/PS. Further study through scanning electron microscope (SEM) verified the entrapment of bacterial cells by TB-EPS, protecting them against electrolysis disruption. Comparatively, electrolysis integrated with S 2 O 8 2 - /Fe(II) oxidation was able to effectively disrupt the protective barrier and crack the entrapped cells, releasing the water inside EPS and cells. Therefore, the destruction of both TB-EPS and cells is the fundamental reason for the enhanced dewaterability.
05/01/2013 00:00:00
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3.1.15 Electro-dewatering
Laboratory device to characterize electrokinetic geocomposites for fluid fine tailings dewatering
The oil sands industry usually leads to the production of large quantities of mineral waste, such as fluid fine tailings (FFT), whose disposal is often challenging. Electrokinetic geocomposites (eGCPs) installed into the FFT disposal area may improve in situ dewatering, as eGCPs can drain water expulsed during FFT consolidation as well as impose a voltage across FFT to displace water by electro-osmosis. This paper presents a laboratory device specifically developed to evaluate eGCP performance for sludge dewatering. Based on the oedometer principle, the device aims at studying sludge consolidation as a function of boundary conditions (mechanical stress and (or) voltage), with drainage and electrical conduction ensured by two eGCPs positioned on both sides of the sludge layer. Preliminary results obtained with one particular eGCP are presented: the solids content was increased from 42% to 66%, which led to a significant improvement of the shear strength from nearly 0 kPa to a mean value of 40 kPa. The ener...
04/01/2015 00:00:00
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3.1.16 Electro-dewatering
METHOD FOR THE DEWATERING OF MANURE
The method shall find application in farms where the animalsare raised without a lay and the manure is in wet condition, aswell as in cases when the preparation of compost with presetphysicochemical characteristics is required. It reduces thedewatering time, the loss of nitrogen is reduced and the physicalproperties of the individual fractions are improved. Loading,transportation and spreading of the manure for the existingmachines is facilitated and the contamination of the soils, groundwaters and the air by separating toxic compounds is avoided. Themethod includes separation of the solid from the liquid phase bymeans of electroosmosis of the treated material by means ofelectrodes which do not contaminate the environment and areconnected to the electric network by means of a rectifiermaintaining voltage not higher than 50V. The solid phase plays thepart of semipermeable membrane.3 claims, 1 figure
01/29/1999 00:00:00
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3.1.17 Electro-dewatering
Performance evaluation of electrocoagulation and electrodewatering system for reduction of water content in sewage sludge
Electrocoagulation is applied to sewage sludge as a pretreatment process of an electrodewatering system to reduce the water content of sludge generated in wastewater treatment. The electrodewatering system, by incorporating an electric field as an additional driving force to the conventional pressure dewatering, has been evaluated as a function of an electrode material, applied voltage and filtration time. Experiments were carried out using sewage sludge with a pressure up to 392.4 kPa and applied electrical field ranging up to 120 V/cm. Mass median diameter of the sewage sludge by the effect of electrocoagulation increases from 34.7 µm to the 41.3 µm. The final water content of sewage sludge in the combination of both electrocoagulation and electrodewatering system can be reduced to 55 wt%, as compared to 78 wt% achieved with pressure dewatering alone. The combination of electrocoagulation and electrodewatering system shows a potential to be an effective method for reducing the water content in sludge.
03/01/2006 00:00:00
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3.1.18 Electro-dewatering
Procedures for the combined processing of sludges and effluents
L'invention concerne un procede combine de traitement des boues impliquant d'une part un traitement par electro-osmose d'une boue permettant de deshydrater la boue, generant ainsi au moins un effluent, et d'autre part un traitement de cet effluent par electrocoagulation ou electroflottation. The invention relates to a combined method of treatment of sludge involving firstly treatment with electroosmosis of a slurry for dewatering the sludge, thereby generating at least one effluent, and on the other hand treatment of this effluent by electrocoagulation or electroflotation. L'invention concerne egalement un procede de traitement des effluents impliquant d'une part un traitement par electrocoagulation ou electroflottation d'un effluent, generant ainsi une boue a traiter et un effluent traite, et d'autre part un traitement de cette boue a traiter par electro-osmose de facon a la deshydrater. The invention also relates to an effluent treatment process involving firstly a electrocoagulation treatment or electroflotation an effluent, thereby generating a slurry to be treated and a treated effluent, and on the other hand a processing of this sludge to be treated electro-osmosis so as to dehydrate. Les procedes de l'invention sont utiles afin de decontaminer des effluents et des boues. The methods of the invention are useful to decontaminate effluent and sludge. Ce procedes peuvent en outre permettre d'obtenir un niveau avance These methods can further help to get an advanced level de purification des boues et effluents traites. purification of sludge and treated effluent.
03/16/2004 00:00:00
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3.1.19 Electro-dewatering
REMEDIATION AND DEWATERING OF DREDGED SLURRY AND MINE TAILING WITH VACUUM METHOD AND ELECTROKINETIC PHENOMENON(VACUUM-ELECTROKINETIC DEWATERING AND REMEDIATION METHOD)
PURPOSE: A remediation and dewatering of dredged slurry and mine tailing with vacuum method and electrokinetic phenomenon(vacuum-electrokinetic dewatering and remediation method) is provided, which can remove heavy metal contained in river bed sediment and highly moisturized mine tailing by desorbing heavy metal by electrokinetic phenomenon and by removing the desorbed heavy metal by electrophoresis and mud flow caused by electro-osmosis and vacuum-dehydration at water discharge material served also as a cathode. The system can also facilitate dewatering by smoothly removing pore water by vacuum-dehydration and electro-osmosis. CONSTITUTION: In the purifying and dewatering treatment method of river bed sediment and highly moisturized mine tailing contaminated with heavy metal within a shortened time by a vacuum-dehydration and electrokinetic phenomenon, hydrogen ion generated by electrolysis at anode(3) migrates toward the soil sample by electrophoresis caused by electrostatic force and mud flow caused by electro-osmosis and vacuum-dehydration to separate heavy metal adsorbed onto the surface of soil particle, and the desorbed heavy metal ions migrate toward water draining material(4) served also as a cathode by electrophoresis caused by electrostatic force and mud flow caused by electro-osmosis and vacuum-dehydration to remove heavy metal and at the same time smoothly remove pore water by vacuum-dehydration and electro-osmosis.
07/28/2003 00:00:00
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3.1.20 Electro-dewatering
Solidifying comprehensive recovery method of electroplating sludge ferrite
The invention relates to a solidifying comprehensive recovery method of electroplating sludge ferrite. The sludge is heated, so that sticky organic matters in the sludge can be hydrolyzed at a continuously constant temperature of 80 DEG and under the weak alkaline condition of pH 9.2, and then the colloid structure of the sludge can be broken and the dewaterability of the sludge can be improved; the solidifying comprehensive recovery method comprises the specific steps of sludge melting and acid pickling, sludge-water separation, regulating the pH value to 9.2 and stirring evenly, stirring at the speed of 45r/min and heating, when the temperature of the mixed solution reaches 80 DEG C, heating at the constant temperature of 80 DEG C for 2 hours without stirring, generating magnetic black Fe3O4 crystals in the solution at last, separating the Fe3O4 crystals in the solution by use of a magnetic separator, and obtaining the Fe3O4 crystal relatively high in purity after separation. The solidifying comprehensive recovery method of the electroplating sludge ferrite has the beneficial effect that the ferrite solidified product has the characteristics of stable solidification, magnetism, further productization and the like.
06/10/2015 00:00:00
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3.1.21 Electro-dewatering
The effect of the addition of fly ash to municipal digested sludge on its electroosmotic dewatering
Effective handling of municipal digested sludge requires that the product cake have low water content. To this end, we investigated the change in sludge dewaterability after the addition of fly ash to municipal digested sludge, dewatering of which is difficult because of its high organic content. The performance of the dewatering is compared with that of electroosmotic dewatering (EDW) and conventional mechanical dewatering (CMD). Fly ash classified by sieving to the size of 25–75 μm and >75 μm is added to the municipal digested sludge by 10, 20, and 50 wt% by wet base. When adding fly ash particles to municipal digested sludge, dewatering efficiency improved with smaller fly ash particle size and with increase in the amount. When sludge was dewatered using an electroosmotic dewatering method, the dewatering efficiency is improved about 40% by adding fly ash of 25–75 μm particle size with 20 wt% when compared with conventional mechanical dewatering method without adding the fly ash. It is concluded that fly ash particles rich in inorganic material are helpful in the dewatering process when added to municipal digested sludge and EDW is more effective than CDW.
10/01/2011 00:00:00
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3.1.22 Electro-dewatering
The feasibility of electro-osmotic belt filter dewatering technology at pilot scale
Sewage sludge is typically dewatered using drying beds, belt filter presses or centrifuges. Mechanical dewatering of sludge is costly in terms of capital and running costs, especially the flocculent. In an attempt to address the need for more cost-effective dewatering technologies, electro-osmotic belt filtering was developed by Smollen and Kafaar in 1995. Themechanical equipment resembles a belt filter press but the belts are stainless steel, woven belts, which act as the electrodes. In this study, thefeasibility of the technology was tested at pilot scale using wasteactivated-, anaerobically digested- and dissolved air flotation sludge. The parameters which were investigated includes the applied voltage, polyelectrolyteusage and sludge feed rate. Applied voltage of between 15 and 25 volts increased the dewatering significantly in the waste activated- and anaerobically digested sludge. Applying a voltage in dissolved air flotation sludge could not enhance the efficiency of dewatering, unless stored to de-air. The technology was found as sensitive to polyelectrolyte dosages as belt presses. The performance of the electro-osmotic belt filter was sensitive to feed rate, but performed well with non-thickened waste activated sludge (0.61% solids), resulting in cake solids above 20%.
04/01/2000 00:00:00
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3.1.23 Electro-dewatering
A METHOD OF PURIFYING LIGNIN BY SUBJECTING A SLURRY COMPRISING LIGNIN TO AN ELECTRIC FIELD

Process for sulphur removal, by using dewatering, of a slurry comprising a lignin, wherein the process comprises the following steps: a) providing a slurry comprising lignin, b) subjecting the slurry to an electric field inducing the liquid and the polar, molecules, species or components thereof such as ions, of the slurry to flow, optionally combined with a pressure force and/or a suction force, c) separating the liquid from the lignin , thus obtaining a liquid depleted purified lignin, optionally in slurry form. The process according to claim 1 also comprising the following steps: d) adding a washing liquid, such as an organic solvent or water or a combination thereof, and/or a pH controlling agent, such as CO2, to the liquid depleted slurry or during dewatering, e) subjecting the slurry of step d) to an electric field inducing the washing liquid of the slurry to flow, f) separating the washing liquid from the slurry, thus obtaining a purified lignin, and g) optionally repeating steps d) - f), preferably at least 3 times. The process according to claim 1 **characterized in that** the dewatering is done by electro-osmosis. The process according to any one of the preceding claims **characterized in that** an electric field with a voltage of 10-200 V is used, preferably 10-100 V, whereby said voltage may be AC or DC or a combination of both. The process according to any one of the preceding claims **characterized in that** pressure and/or suction and/or ultrasound and/or magnetic induced separation also is applied in order to dewater the slurry. The process according to claim 5 **characterized in that** the pressure is applied after the electric field has been applied and the dewatering has started. The process according to any one of claims 5-6 **characterized in that** the pressure is a mechanical pressure. The process according to any one of the preceding claims **characterized in that** the dry content of the slurry comprising lignin, before dewatering, is 1-50% by weight. The process according to any one of the preceding claims **characterized in that** the temperature of the slurry during the dewatering is above 30 °C and below 140°C, preferably above 30°C and below 100°C. The process according to any one of the preceding claims wherein the washing liquid is water and/or an organic solvent, or a combination thereof. The process according to any one of the preceding claims followed by, or preceded by, a counter-ion change and/or one or more washing steps, such as acid or alkaline washing steps, and/or a filtration step, such as ultrafiltration step, and/or a fractionation step.
09/30/2015 00:00:00
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3.1.24 Electro-dewatering
CAPACITATIVE ELECTROKINETIC DEWATERING OF SUSPENSIONS
Capacitive electrokinetic densification, decontamination and dewatering of suspensions and soils can be performed while controlling and/or preventing chemical and pH changes in the densified material and extracted water. High electrical capacitance electrodes or Electric Double Layer Capacitor (EDLC) electrodes are used which can operate without redox reactions occurring on their surfaces until their developed voltage reaches the standard electrode potential of the electrode. Water-retaining, flexible covers for the EDLC electrodes have drainage and filtering capabilities and are made of a fabric which allows the passage of ions, water and electricity therethrough and facilitate continuous electrical contact between the EDLC electrode and the surrounding suspension.
**1**. A capacitive electrokinetic process for densifying solids and recovering water from colloidal suspensions without changes in chemical composition and pH of the densified material and the extracted water, the process comprising the steps of: a) providing an insulated container, the insulated container including at least one outlet drain line for removing water therefrom; b) providing an electric current power supply for generating an electric field through the suspension, wherein the power supply includes a positive pole and a negative pole and is capable of polarity reversal; c) providing at least one pair of high capacitance electric double-layer capacitor (EDLC) electrodes connected to opposite poles of the power supply, wherein each electrode of the at least one pair of EDLC electrodes has a specific capacitance of at least 1.0 farad per gram and is spaced apart from the other electrode within the insulated container; d) providing each EDLC electrode with an electrode cover for placement over the EDLC electrode, wherein each electrode cover is made of a fabric which allows the passage of ions, water and electricity therethrough and facilitates electrical contact between the EDLC electrode and the surrounding suspension; e) providing each electrode cover with a drain conduit, wherein each drain conduit is positioned below its corresponding EDLC electrode and is hydraulically connected to its corresponding electrode cover and to the at least one outlet drain line; f) providing a suspension to be treated in the insulated container; g) applying a potential difference between the EDLC electrodes via the power supply to generate an electric field through the suspension, wherein electric current flow through the suspension is established and maintained by the EDLC electrodes without the occurrence of redox reactions at their surfaces so long as the potential difference between the EDLC electrodes and the ions in the surrounding suspension ions is below the standard electrode potential of the ions in the surrounding suspension; h) detecting the initiation of redox reactions at the EDLC electrode surfaces; i) upon the detection of redox reactions at the EDLC electrode surfaces, reversing the electric field direction through the suspension by reversing the polarity of the potential difference applied between the EDLC electrodes via the power supply; j) removing water from the insulated container through the at least one outlet drain to achieve water extraction from the suspension and densification of solids within the suspension; k) removing the treated suspension from the insulated container; and l) repeating steps (g) through (k). <br/>**2**. The process of claim 1 , wherein the step of (h) detecting the initiation of redox reactions at the EDLC electrode surfaces is performed by detecting pH changes in the water recovered at the at least one outlet drain line. <br/>**3**. The process of claim 1 , wherein the step of (h) detecting the initiation of redox reactions at the EDLC electrode surfaces is performed by detecting voltage changes between the EDLC electrode surfaces and the suspension. <br/>**4**. The process of claim 3 , wherein detecting voltage changes between electrodes and various points in the suspension is used as a guide to affect removal of the densified material from the dewatering cell. <br/>**5**. The process of claim 1 , wherein the specific capacitance of the high capacitance EDLC electrodes is more than 1 farad per gram and less than 5 farads per gram. <br/>**6**. The process of claim 1 , wherein the specific capacitance of the high capacitance EDLC electrodes is more than 5 farads per gram and less than 50 farads per gram. <br/>**7**. The process of claim 1 , wherein the specific capacitance of the high capacitance EDLC electrodes is more than 50 farads per gram and less than 400 farads per gram. <br/>**8**. The process of claim 1 , wherein the specific capacitance of the high capacitance EDLC electrodes is more than 400 farads per gram. <br/>**9**. The process of claim 1 , wherein the suspension to be treated is a colloidal suspension containing charged particles and electro-active materials. <br/>**10**. The process of claim 1 , wherein the suspension to be treated is selected from the group consisting of oil sands tailings, clay-water suspensions such as Mature Fine Tailings (MFT), dispersions or suspensions of inorganic particles that are a by-product of mining, manufacturing or other industrial processes, food and food processing waste suspensions, biological wastes, and biomass sludges. <br/>**11**. An apparatus for capacitive electrophoretic densification of solids and capacitive electro-osmotic removal of fluids from a colloidal suspension, the apparatus comprising: a) an insulated container for receiving and containing a suspension to be treated, the insulated container including at least one outlet drain line for removing water therefrom; b) an electric current power supply for generating an electric field through the suspension, wherein the power supply includes a positive pole and a negative pole and is capable of polarity reversal; c) at least one pair of high capacitance electric double-layer capacitor (EDLC) electrodes connected to opposite poles of the power supply, wherein each electrode of the at least one pair of EDLC electrodes has a specific capacitance of at least 1.0 farad per gram and is spaced apart from the other electrode within the insulated container; d) at least one pair of electrode covers placed over the at least one pair of EDLC electrodes, wherein each electrode cover is made of a fabric which allows the passage of ions, water and electricity therethrough and facilitates electrical contact between the EDLC electrode and the surrounding suspension; and e) at least one pair of drain conduits positioned below the at least one pair of EDLC electrodes, wherein each drain conduit is hydraulically connected one of the at least one pair of electrode covers and to the at least one outlet drain line; <br/>**12**. The apparatus of claim 11 , wherein the suspension to be treated is a colloidal suspension containing charged particles and electro-active materials. <br/>**13**. The apparatus of claim 11 , wherein the suspension to be treated is selected from the group consisting of oil sands tailings, clay-water suspensions such as Mature Fine Tailings (MFT), dispersions or suspensions of inorganic particles that are a by-product of mining, manufacturing or other industrial processes, food and food processing waste suspensions, biological wastes, and biomass sludges. <br/>**14**. The apparatus of claim 11 , wherein the specific capacitance of the high capacitance EDLC electrodes is more than 1 farad per gram and less than 5 farads per gram. <br/>**15**. The apparatus of claim 11 , wherein the specific capacitance of the high capacitance EDLC electrodes is more than 5 farads per gram and less than 50 farads per gram. <br/>**16**. The apparatus of claim 11 , wherein the specific capacitance of the high capacitance EDLC electrodes is more than 50 farads per gram and less than 400 farads per gram. <br/>**17**. The apparatus of claim 11 , wherein the specific capacitance of the high capacitance EDLC electrodes is more than 400 farads per gram.
09/17/2018 00:00:00
Link to Patent
3.1.25 Electro-dewatering
Control System And An Adaptive Electrokinetic Dewatering System Incorporating Same For Dewatering Tailings
An adaptive electrokinetic dewatering system for dewatering slurry and soil deposits, including tailings deposits and a control system therefor. The control system automatically determines an optimal applied power specification, including sets of power parameters to be applied to the deposit being dewatered and when to apply each set of power parameters during the electrokinetic dewatering process. Furthermore, the control system automatically adjusts the applied power specification throughout the course of the dewatering process to account for the changing properties of the deposit. The control system determines the applied power specifications and adjustments to be made to them by simulating the electrokinetic dewatering process using a simulator which incorporates the latest measurements of the electrical, physical and chemical properties of the deposit being dewatered. The control system uses the simulator to forecast the dewatering performances of alternative applied power specifications and selects and applies the alternative applied power specification having a forecast dewatering performance that satisfies one or more switching criteria set by an operator.
**1**. A control system for use in an electrokinetic dewatering system for dewatering a deposit said control system comprising: inputs and outputs; a programmed central processor; wherein said inputs include at least: sensor data from at least one sensor positioned in said deposit and adapted to measure present properties of said deposit; and an optimal applied power schedule including a series of applied power specifications with switching criteria for each applied power specifications indicating when a new applied power specification should be applied; and wherein said programmed central processor is configured to: a) simulate an electrokinetic dewatering process applied to said deposit based on said sensor data; b) generate at least one alternative applied power specification, that when used in said simulation, satisfies said one or more of the switching criteria; and c) select the said at least one alternative applied power specification that best satisfies said one or more switching criteria; and wherein said outputs include an applied power specification and commands for controlling said electrokinetic dewatering system in accordance with said applied power specification. <br/>**2**. The control system according to claim 1 , wherein said alternative applied power specification is one of a series of applied power specifications that together comprise an applied power schedule for said dewatering process. <br/>**3**. The control system according to claim 1 , wherein said deposit comprises one or more of tailings, mature fine tailings (MFT), fluid fine tailings (FFT), sewage sludge, drilling mud, dredging spoils and soft clayey soils. <br/>**4**. The control system according to claim 1 , wherein said one or more switching criteria include a desired total amount of energy consumed, a desired maximum rate of energy consumption, a desired final dewatered state for said deposit, a desired total amount of consolidation of said deposit, a desired dewatering rate, a desired total elapsed time for the electrokinetic dewatering process and combinations thereof. <br/>**5**. The control system according to claim 1 , wherein said present properties of said deposit comprises at least one of a mudline or a soil surface elevation, a local electric field strength and a local pore pressure. <br/>**6**. The control system according to claim 1 , wherein said applied power specification comprises at least one power parameter that is a stepped increase in the applied voltage at the start-up of each power pulse including the number of steps, the voltage increment for each step and their duration, the peak voltage, the duration of the peak voltage, the duration of the "rest" period between pulses of power, the frequency of intermittent periods of reversed polarity for some or all electrodes, the duration of each polarity reversal, the duration of the "rest" periods between polarity reversals and resumption of normal polarity applied power pulses. <br/>**7**. The control system according to claim 1 , wherein said inputs further comprise a user interface configured to receive input from an operator and to provide said one or more switching criteria to said central processor in response to said input from said operator. <br/>**8**. The control system according to claim 6 , wherein said user interface is adapted to be operatively connected to a remote access device having an input device, an output device or a combination thereof. <br/>**9**. The control system according to claim 6 , wherein said user interface comprises an input device, an output device or a combination thereof. <br/>**10**. The control system according to claim 1 , wherein said central processor is further configured to receive said sensor data from said sensors at regular intervals or continuously. <br/>**11**. The control system according to claim 1 , further comprises a data acquisition and storage system configured to receive and store said sensor data from said at least one sensor and make said received and stored sensor data accessible to said programmed central processor. <br/>**12**. The control system according to claim 1 , wherein said steps a) to c) comprise: d) generating said at least one alternative applied power specification; e) simulating said electrokinetic dewatering process using said at least one alternative applied power specification and said sensor data to generate a forecast dewatering performance of said at least one alternative applied power specification; f) evaluating said forecast dewatering performance of said at least one alternative applied power specification using said one or more switching criteria; g) selecting said optimal alternative applied power specification based on results of said evaluating step f) wherein at least one of said at least one alternative applied power specification satisfies said one or more switching criteria, otherwise repeating said steps d) to g). <br/>**13**. The control system according to claim 12 , wherein said step g) selects a first one of said at least one alternative applied power specifications to satisfy said one or more switching criteria as said optimal alternative applied power specification. <br/>**14**. The control system according to claim 12 , wherein said step d) generates a plurality of said alternative applied power specifications, said step e) generates a plurality of said forecast dewatering performances based on said plurality of said alternative applied power specifications, said step f) evaluates said plurality of said forecast dewatering performances using said one or more switching criteria, said step g) selects the best one of said plurality of said alternative applied power specifications that satisfies said one or more switching criteria as said optimal alternative applied power specification. <br/>**15**. The control system according to claim 12 , wherein said programmed central processor is further configured to assign a dewatering performance score to each of one of said plurality of said alternative applied power specifications generated in said step d), said steps d) to g) repeat until a difference between any two dewatering performance scores is less than a predetermined difference and said step g) selects the said alternative applied power specification having the best dewatering performance score. <br/>**16**. The control system according to claim 12 , wherein said plurality of said alternative applied power specifications generated at said step d) is limited to a predetermined minimum number or a predetermined maximum number. <br/>**17**. The control system according to claim 12 , wherein said forecast dewatering performance includes a forecast amount of energy consumed, a forecast rate of energy consumption, a forecast final dewatered state for said deposit, a forecast desired total amount of consolidation of said deposit, a forecast dewatering rate and combinations thereof. <br/>**18**. The control system according to claim 12 , wherein said programmed central processor is further configured to monitor said sensor data, generate a real dewatering performance of said electrokinetic dewatering process using said sensor data and to compare said real dewatering performance to said forecast dewatering performance; and wherein said real dewatering performance departs from said forecast dewatering performance by a predetermined amount, said programmed central processor initiates said steps d) to g). <br/>**19**. The control system according to claim 18 , wherein said real dewatering performance includes a real total elapsed time since the start of said electrokinetic dewatering process, a real amount of energy consumed by said electrokinetic dewatering process since said start, a real rate of energy consumed by said electrokinetic dewatering process at a time of said real dewatering, a real dewatered state of said deposit at said time, a real amount of consolidation of said deposit at said time, a real dewatering rate of said electrokinetic dewatering process at said time and combinations thereof. <br/>**20**. The said central processor as part of said control system according to claim 1 is further configured such that when said control system is incorporated in said electrokinetic dewatering system, said commands control a flow of electrical power to said deposit. <br/>**21**. The control system according to claim 1 , further comprises a table of possible power parameters, each associated with a predetermined range of values, wherein said central processor is configured to generate said at least one alternative applied power specification by selecting one or more of said possible power parameters and assigning to each said selected one or more possible power parameters a random value falling within said predetermined range of values. <br/>**22**. An adaptive electrokinetic dewatering system for dewatering a deposit, said system comprising: the control system as claimed in claim 1 ; a source of electrical power; at least one power distribution substation operably connected to said source of electrical power; at least one electrode array operably connected to said at least one said power distribution substation, said at least one electrode array being positioned in said deposit and adapted to apply electric power to said deposit; and said at least one sensor being operably connected to said control system; wherein said commands control said source of electrical power and said at least one power distribution substation to apply electrical power to said deposit via said at least one electrode array in accordance with said applied power specification. <br/>**23**. The adaptive electrokinetic dewatering system according to claim 22 , wherein said at least one sensor comprises a local electric field strength sensor, a mudline height or soil surface elevation sensor or a pore water sensor. <br/>**24**. A method of adaptively dewatering a deposit using an electrokinetic dewatering process, said method comprising the steps of: a) determining one or more dewatering performance criteria; b) measuring present properties of said deposit being dewatered; c) evaluating the current applied power specification relative to these performance criteria and making a determination if the applied power specification is appropriate; d) generating at least one alternative applied power specification; e) simulating said electrokinetic dewatering process applied to said deposit based on said present properties of said deposit and said at least one alternative applied power specification and generating a forecast dewatering performance based on said simulation; f) determining whether said forecast dewatering performance of said at least one alternative applied power specification satisfies said one or more switching criteria; g) if so, selecting an optimal one of said at least one alternative applied power setting that has the best forecast dewatering performance for use in said electrokinetic dewatering process, otherwise repeating said steps b) to f); and h) providing an applied power specification based on said optimal alternative applied power specification and controlling said electrokinetic dewatering process in accordance with said applied power specification. <br/>**25**. The method according to claim 24 , wherein said deposit comprises mine tailings, mature fine tailings (MFT), fluid fine tailings (FFT), sewage sludge, drilling mud, dredging spoils or soft clayey soils. <br/>**26**. The method according to claim 24 , wherein said one or more switching criteria include a desired total amount of energy consumed, a desired maximum rate of energy consumption, a desired final dewatered state for said deposit, a desired total amount of consolidation of said deposit and combinations thereof. <br/>**27**. The method according to claim 24 , wherein said present properties of said deposit comprises at least one of a mudline, a local electric field strength and a local pore pressure. <br/>**28**. The method according to claim 24 , wherein said forecast dewatering performance includes a forecasted amount of energy consumed, a forecasted rate of energy consumption, a forecasted final dewatered state for said deposit, a forecasted desired total amount of consolidation of said deposit, a forecasted dewatering rate and combinations thereof. <br/>**29**. The method according to claim 24 , wherein said electrokinetic dewatering process comprises applying an electric current to said deposit via a plurality of electrodes placed in said deposit. <br/>**30**. The method according to claim 24 , wherein said one or more switching criteria include a desired total amount of energy consumed, a desired maximum rate of energy consumption, a desired final dewatered state for said deposit, a desired total amount of consolidation of said deposit, a desired dewatering rate, a desired total elapsed time since the start of the electrokinetic dewatering process and combinations thereof. <br/>**31**. The method according to claim 24 , further comprises the step of providing a table of possible power parameters, each associated with a predetermined range of values, wherein said step c) comprises generating said at least one alternative applied power specification by selecting one or more of said possible power parameters and assigning to each said selected one or more possible power parameters a random value falling within said predetermined range of values. <br/>**32**. The method according to claim 24 , wherein said possible power parameter is a stepped increase in the applied voltage at the start-up of each power pulse including the number of steps, the voltage increment for each step and their duration, the peak voltage, the duration of the peak voltage, the duration of the "rest" period between pulses of power, the frequency of intermittent periods of reversed polarity for some or all electrodes, the duration of each polarity reversal, the duration of the "rest" periods between polarity reversals and resumption of normal polarity applied power pulses. <br/>**33**. The method according to claim 24 further comprises monitoring said present properties, generating a real dewatering performance of said electrokinetic dewatering process using said sensor data and to compare said real dewatering performance to said forecast dewatering performance; and when said real dewatering performance departs from said forecast dewatering performance by a predetermined amount, repeating said steps b) to g). <br/>**34**. The method according to claim 33 , wherein said real dewatering performance includes a real total elapsed time since the start of said electrokinetic dewatering process, a real amount of energy consumed by said electrokinetic dewatering process since said start, a real rate of energy consumed by said electrokinetic dewatering process at a time of said generating said real dewatering performance, a real dewatered state of said deposit at said time, a real amount of consolidation of said deposit at said time, a real dewatering rate of said electrokinetic dewatering process at said time and combinations thereof. <br/>**35**. The method according to claim 24 , wherein said step f) selects a first one of said at least one alternative applied power specifications having said forecast dewatering performance satisfying said one or more desired switching criteria as said optimal alternative applied power specification. <br/>**36**. The control system according to claim 24 , wherein said step c) generates a plurality of said alternative applied power specifications, said step d) generates a plurality of said forecast dewatering performances based on said plurality of said alternative applied power specifications, said step e) evaluates said plurality of said forecast dewatering performances using said one or more switching criteria, said step f) selects the best one of said plurality of said alternative applied power specifications that satisfies said one or more switching criteria as said optimal alternative applied power specification. <br/>**37**. The control system according to claim 36 , wherein said programmed central processor is further configured to assign a dewatering performance score to each of one of said plurality of said alternative applied power specifications generated in said step c), said steps c) to e) repeat until a difference between any two dewatering performance scores is less than a predetermined difference and said step f) selects said optimal alternative applied power specification having the best dewatering performance score. <br/>**38**. The control system according to claim 36 , wherein said plurality of said alternative applied power specifications generated at said step c) is limited to a predetermined minimum number or a predetermined maximum number.
02/07/2019 00:00:00
Link to Patent

4. Radiation

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Radiation is the emission or transmission of energy in the form of waves or particles through space or through a material medium. [\[link\]](https://en.wikipedia.org/wiki/Radiation#:\~:text=In%20physics%2C%20radiation%20is%20the,%2C%20and%20gamma%20radiation%20(%CE%B3))


4.1 Ultrasonication

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Sonication is the act of applying sound energy to agitate particles in a sample, for various purposes such as the extraction of multiple compounds from plants, microalgae and seaweeds. Ultrasonic frequencies (>20 kHz) are usually used, leading to the process also being known as ultrasonication or ultra-sonication. [\[link\]](https://en.wikipedia.org/wiki/Sonication) **Highlights:** * This research intended to study the efficiency of ultrasound in dewatering **biological sludge** in wastewater treatment plants under different conditions. In this study, response surface method was used to investigate results and optimum conditions were determined. \[...\] Results of the experiments showed that, the ultrasonic method significantly **increases the SRF**. Also based on response surface method, the best performance of ultrasonic application in sludge treatment is achievable at the following conditions: **625 W ultrasound power**, 2.7 L sample volume and 13 min ultrasonic exposure duration. [\[Art. #ARTNUM\]](#article-95998-2591698800) * **Double-frequency ultrasonic generating trough** was applied to improve dewaterability of sludge from secondary settling tanks \[...\] The optimal operating parameter was frequency of 19kHz, energy density of **0.050W/mL**, and treating time of 30s. [\[Art. #ARTNUM\]](#article-95998-2382880175) * Experiments were operated for the purposes of dewatering **oily sludge** and reducing sludge volume with ultrasonic technology. The effect of clay dosage, temperature, ultrasonic time and emulsifier dosage were assessed respectively. \[...\] **500ml volume of oily sludge decreased to 40ml.** Oil concentration is up to 158.45mg/l in 460ml separation fluid. This method may obtain the economical benefit and be feasible in technology. [\[Art. #ARTNUM\]](#article-95998-2088754656) * The **high-power ultrasound approach** seemed to be particularly effective. The mechanisms involved include atomization, microstructural effects, cavitation, and the sponge effect, which work to reduce both internal and external resistances. Applied in the right way, ultrasound could become a very effective way to **enhance mechanical dewatering.**[ \[Art. #ARTNUM\]](#article-95998-2773163778) **Combined with treatments:** * This experiment adopted supersound and **polymeric aluminum ferric chloride (PAFC)** dewatering excess sludges. \[...\] supersound singly dewatered excess sludges. The optimum technological condition was the optimum power of **150W** and time of 2.5min. Lastly, the combination of supersound and PAFC sludge dewatered excess sludges and **moisture content was reduced to 70.01%**.[ \[Art. #ARTNUM\]](#article-95998-1976021705)

4.1.1 Ultrasonication
An ultrasonically enhanced inclined settler for microalgae harvesting
Microalgae have vast potential as a sustainable and scalable source of biofuels and bioproducts. However, algae dewatering is a critical challenge that must be addressed. Ultrasonic settling has already been exploited for concentrating various biological cells at relatively small batch volumes and/or low throughput. Typically, these designs are operated in batch or semicontinuous mode, wherein the flow is interrupted and the cells are subsequently harvested. These batch techniques are not well suited for scaleup to the throughput levels required for harvesting microalgae from the large-scale cultivation operations necessary for a viable algal biofuel industry. This article introduces a novel device for the acoustic harvesting of microalgae. The design is based on the coupling of the acoustophoretic force, acoustic transparent materials, and inclined settling. A filtration efficiency of 70 ± 5% and a concentration factor of 11.6 ± 2.2 were achieved at a flow rate of 25 mL·min−1 and an energy consumption of 3.6 ± 0.9 kWh·m−3. The effects of the applied power, flow rate, inlet cell concentration, and inclination were explored. It was found that the filtration efficiency of the device is proportional to the power applied. However, the filtration efficiency experienced a plateau at 100 W L−1 of power density applied. The filtration efficiency also increased with increasing inlet cell concentration and was inversely proportional to the flow rate. It was also found that the optimum settling angle for maximum concentration factor occurred at an angle of 50 ± 5°. At these optimum conditions, the device had higher filtration efficiency in comparison to other similar devices reported in the previous literature. © 2014 American Institute of Chemical Engineers Biotechnol. Prog., 31:414–423, 2015
03/01/2015 00:00:00
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4.1.2 Ultrasonication
Application of high-power ultrasound to enhance fluid/solid particle separation processes
Abstract The separation of fine particles from gases or liquids is a topic of permanent industrial attention. The use of ultrasonic energy to assist conventional separation techniques seems to be very promising. The adequate applications of high-intensity ultrasonic fields may contribute to improve the efficiency and capacity of the separation methods presently used. The specific mechanisms to ultrasonically enhance separation processes basically depend on the medium to be treated. In gas suspensions, where very fine particles have to be removed, ultrasonic action involves agglomeration of particles in order to increase their size and, consequently, to improve collection efficiency of conventional filters. In liquid suspensions, agglomeration is, in general, less efficient than in gases. Nevertheless, the ultrasonic energy is useful to dewater fine-particle high-concentration suspensions such as slurries and sludges. This paper deals with the application of acoustic energy to assist fluid/solid separation processes in gas and liquid suspensions and presents some theoretical and experimental results in specific applications.
03/01/2000 00:00:00
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4.1.3 Ultrasonication
Changes of some sewage sludge parameters prepared with an ultrasonic field
Studies of sewage sludge conditioning by ultrasonic field concentrate on determination of the increase of water removal effect, which depends on kind of sludge and chemical compounds used in the dewatering process. An attempt was made to find new methods of sludge preparation before dewatering. Tests presented here focused on digested and difficult dewatered sludge. The sludge was dewatered on a vacuum filter after conditioning with polyelectrolytes and the ultrasonic field. The microscopic analysis was an additional criterion to evaluate changes in the sludge structure after preparation. The polyelectrolyte dose of 3 mg/g d.m. sonicated within 15 sec. resulted in the 50% decrease of sludge volume. Results presented confirmed our previous experiences, concerning the relation between conglomerates of sludge and the effect of dewatering.
12/01/1997 00:00:00
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4.1.4 Ultrasonication
Dewaterability of waste activated sludge with ultrasound conditioning.
Abstract This study investigated the potential benefits of ultrasound-conditioned sludge dewatering treatments with specific energy dosages from 0 to 35,000 kJ/kg total solids (TS). Capillary suction time (CST) and specific resistance of filtration (SRF) were used to evaluate sludge dewaterability. Sludge water distribution was measured by the drying test and mechanical separation methods. Both extracellular polymeric substance (EPS) content and sludge particle size were determined in an attempt to explain the observed changes in sludge dewaterability. The results indicated that application of low specific energy dosages ( 4400 kJ/kg TS) significantly deteriorated sludge dewaterability. The optimal specific energy to give maximal dewaterability characteristics was found to be 800 kJ/kg TS, which generated sludge with optimal EPS concentration (400–500 mg/l) and particle size distribution (80–90 μm diameter). Subjecting sludge to a combination of cationic polymer and ultrasound pretreatments did not present any clear advantages over polymeric conditioning alone for improving sludge dewaterability. The effects of cationic polymer treatment predominated over those of ultrasound pretreatment when both were used together.
02/01/2009 00:00:00
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4.1.5 Ultrasonication
Dewatering Excess Sludges of Sanitary Sewage by Supersound and PAFC
This experiment adopted supersound and polymeric aluminum ferric chloride (PAFC) dewatering excess sludges. Firstly, aluminum chloride and ferric chloride were synthetized to a novel inorganic flocculant ——PAFC and the optimal molar ratio of A1 and Fe was 7:3. Secondly, PAFC singly dewatered excess sludges. The optimum technological conditionwas the optimum dosage of 120mg/L and pH of 8. As a result , the sludge water content decreased from 87.48% to 70.87%. Thirdly, supersound singly dewatered excess sludges. The optimum technological condition was the optimum power of 150W and time of 2.5min. Lastly, the combination of supersound and PAFC sludge dewatered excess sludges and moisture content was reduced to 70.01%.
08/01/2013 00:00:00
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4.1.6 Ultrasonication
Dewatering Research of Sludge with High Moisture Content
Keywords: Sludge treatment, Dewatering, High moisture content, Biomass, Ultrasonic wave. Abstract. Recent years, municipal sludge received more and more attention as a kind of negative by-product of the urbanization. The technology of dewatering plays a critical role in the sludge handling process. However, domestic academic research in the field of dewatering is not sufficient at present .The dewatering of municipal sludge facing the problem of poor dehydration and high energy consumption .In this paper , the test device is designed and built to test the dewatering characteristics of sludge in different complex working conditions .And by imposing different pressure ,temperature ,mass ,and different power of ultrasonic wave ,the correct experimental data are gotten. And the dewatering rate and dehydration power for unit mass can be given by analysis and calculation. Finally the optimal condition was selected according to the principle of minimize power consumption.
01/01/2016 00:00:00
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4.1.7 Ultrasonication
Enhanced sludge dewatering based on the application of high-power ultrasonic vibration
Abstract Interest in producing heat and power using municipal wastewater sewage sludge as a fuel is increasing worldwide. Since its water content is initially high, sludge must be dewatered and further dried if it is to serve as an effective fuel for combustion. However, to maximize net energy production, the drying processes must use as little energy as possible. The water content in sewage sludge comprises both unbound and bound water. Unbound water content is typically extracted using a number of mechanical dewatering techniques. In terms of total solids content (TS), dewatering processes can take sludge from an initial 3–5% to a more solid 25–45% TS with minimal energy expenditure. However, this level of dryness is not sufficient for effective combustion. To produce an effective fuel, TS levels must be increased. Achieving high level of dryness involves removing any remaining unbound water and substantial bound water content as well. Heat is normally applied to accomplish this by changing the phase of the water from liquid to vapor. Although dewatering is energy-efficient, thermal drying is not. The energy used to thermally dry sludge can be two orders of magnitude greater than the energy used for dewatering. Therefore, to expend as little energy as possible to achieve the needed dryness, conventional dewatering processes clearly must be improved. This paper describes work carried out to identify promising ways to efficiently enhance the dewatering and drying of sewage sludge. Available dewatering approaches were reviewed and experiments were carried out to examine the relative effects of temperature, atmospheric pressure, and high-power ultrasound. The high-power ultrasound approach seemed to be particularly effective. The mechanisms involved include atomization, microstructural effects, cavitation, and the sponge effect, which work to reduce both internal and external resistances. Applied in the right way, ultrasound could become a very effective way to enhance mechanical dewatering.
03/01/2018 00:00:00
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4.1.8 Ultrasonication
Experimental Study on Ultrasonic Dehydration of Oily Sludge
Experiments were operated for the purposes of dewatering oily sludge and reducing sludge volume with ultrasonic technology. The effect of clay dosage, temperature, ultrasonic time and emulsifier dosage were assessed respectively. The result shows that: when the temperature is 40°C, ultrasonic time is 20min; demulsifier dosage is 15ml and clay dosage is 15g, 500ml volume of oily sludge decreased to 40ml. Oil concentration is up to 158.45mg/l in 460ml separation fluid. This method may obtain the economical benefit and be feasible in technology. Treating oily sludge with ultrasonic technology is good at the subsequent processing of oil sludge.
08/01/2013 00:00:00
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4.1.9 Ultrasonication
Influence of ultrasonic field on structure and parameters of sewage sludge for dewatering process
The paper discusses the results of experiments with ultrasound application. Ultrasound is applied to change the polyelectrolyte's structure. Presented results indicate that the ultrasonic field may be useful for sewage sludge dewatering.
08/01/1997 00:00:00
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4.1.10 Ultrasonication
Low frequency ultrasonic wave assisted nostoc sphaeroids kutz dewatering and rewatering improving method
The invention relates to a low frequency ultrasonic wave assisted nostoc sphaeroids kutz dewatering and rewatering improving method, and belongs to the technical field of algae dewatering processing. According to the present invention, fresh nostoc sphaeroids kutz is adopted as a raw material, material selecting-grading and washing-impurity removing, low frequency ultrasonic wave pretreatment and draining freezing are performed, the combination of pulse spouting low-frequency microwave and vacuum freeze-drying is used at the early stage, and hot wind drying and packaging storage are used at the later state; the microwave vacuum freeze drying technology is adopted, such that the drying time is shortened, the original shape of the nostoc sphaeroids kutz can be effectively fixed, and the characteristics of complete texture and structure and fast rewatering of the product are retained; with the impulse spouting, the material drying uniformity is easily achieved, and the quality of the nostoc sphaeroids kutz dried product is improved; the subsequent hot wind drying does not significantly affect the quality, the structure and the shape of the product, and can further reduce the energy consumption and the drying time; and during the ultrasonic wave pretreated material dewatering and subsequent ultrasonic wave rewatering process, the material rewatering time can be significantly shortened, and the re-watered material particles are full and have high elasticity.
12/21/2016 00:00:00
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4.1.11 Ultrasonication
Optimization of ultrasonic waves application in municipal wastewater sludge treatment using response surface method
Abstract Today, many limitations are faced in sludge treatment and disposal. Therefore evaluation of different approaches to reduce sludge production in the activated sludge process has attracted great attention. Application of ultrasonic waves in sludge treatment caused to reduce sludge volume and accelerate sludge digestion. This research intended to study the efficiency of ultrasound in dewatering biological sludge in wastewater treatment plants under different conditions. In this study, response surface method was used to investigate results and optimum conditions were determined. Sludge was treated in different conditions as follows: 330–920 W ultrasound power, 1.5–3.9 L sample volume and 6–20 min ultrasonic exposure duration. Then, the effect of waves was studied in terms of SRF (specific resistance to filtration). Results of the experiments showed that, the ultrasonic method significantly increases the SRF. Also based on response surface method, the best performance of ultrasonic application in sludge treatment is achievable at the following conditions: 625 W ultrasound power, 2.7 L sample volume and 13 min ultrasonic exposure duration. A mathematical model for accurate prediction of SRF changes of the sludge was derived using statistical data.
05/01/2017 00:00:00
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4.1.12 Ultrasonication
Study on Improvement of Dewaterability of Sludge by Double-frequency Ultrasonic Generating Trough
Double-frequency ultrasonic generating trough was applied to improve dewaterability of sludge from secondary settling tanks,and optimal operating parameters of ultrasonic generator were studied by orthogonal experiment.The ultrasonic generator could adjust frequency,energy density and treating time flexibly in order to compare sludge dewaterability under different conditions.According to the results,treating time had the most significant influence on sludge dewaterability,energy density was less important than it and frequency was the least.The optimal operating parameter was frequency of 19kHz,energy density of 0.050W/mL,and treating time of 30s.Improvement of sludge dewaterability requires low frequency,low energy density and short treating time. Or sludge dewaterability will be worsened when operating parameters are beyond a certain scale.Ultrasonic generating method has impact on sludge dewaterability.When the frequency was low,single-frequency ultrasonic achieved higher dewaterablity;when the frequency was high,double-frequency ultrasonic had better results.
01/01/2009 00:00:00
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4.1.13 Ultrasonication
The Use of Ultrasonics in the Treatment of Waste Activated Sludge
Abstract The present paper reports on extensive investigations using an ultrasonic treatment of WAS, to study its potential to meet one or all of four objectives: (1) reduce WAS quantities; (2) achieve a better dewaterability; (3) provoke a release of COD from the biosolids, preferably transformed into biodegradable organics and (4) possibly destroy the filamentous micro-organisms responsible for sludge bulking. The experiments are carried out in a batch reactor of volume up to 2.3L. The ultrasonic apparatus consisted of a generator, a converter and a sonotrode, supplied by Alpha Ultrasonics under the brand name of Telsonic. Three different sludge kinds were tested, at approximate concentration (DS/WAS) between 3.5 and 20g·L −1 . The release of COD from the WAS-phase into the filtrate phase is a function of the specific energy-input SE with yields of about 30% achievable at SE-values of 30000 kJ·kg −1 . A major fraction of the COD is transformed into biodegradable organics (BOD). The reduction of DS-fraction of the sludge is equivalent to the COD-release rates. Although the dry solids content (DS) is reduced, the dewaterability of the sludge is not improved. This reflects itself in a slightly decreased dryness of the filter cake using vacuum filtration, and in increased values of the capillary suction time (CST). This more difficult dewaterability is the result of considerably reduced floc sizes, offering an extended surface area. More surface water is bound (CST increases) and the filterability decreases due to clogging of the cake. To reach the same dryness as the untreated cake, the required dosage of poly-electrolyte increases proportionally with the level of ultrasound energy supplied. The ultrasonic reduction of filamentous WAS organisms is not conclusive and very little effect is seen at low intensities and short treatment durations. Microscopic analysis of the WAS identified the dominant presence of Actynomyces. Especially the release of COD and its transformation into BOD certainly merit further research.
02/01/2006 00:00:00
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4.1.14 Ultrasonication
Method and apparatus for thermal processing of biomass

1. A method of thermal processing of biomass, comprising the steps of:subjecting a biomass in a receiving tank to a cracking temperature to undergo a cracking reaction;transferring the biomass to a mixer pump to produce a reaction mixture;directing the reaction mixture into a chamber of an intermediate tank to produce a gaseous fraction and a liquid fraction;cooling down the gaseous fraction to produce fuel;returning a first portion of the liquid fraction and subjecting it again to the cracking temperature in the receiving tank;conducting a second portion of the liquid fraction in a bypass to the chamber of the intermediate tank for separating a further gaseous fraction while fresh biomass is added; andperiodically removing from the intermediate tank settled residual matter. 2. The method of claim 1, wherein the transferring step includes the step of subjecting the biomass to a further cracking reaction in the mixer pump. 3. The method of claim 1, wherein the cracking temperature is in the range of about 250° C. to about 380° C. 4. The method of claim 1, further comprising the step of dewatering the fuel. 5. The method of claim 1, further comprising the step of feeding the fuel to operate a turbogenerator constructed for generating electricity. 6. The method of claim 1, further comprising the steps of combusting the fuel in a turbine, and utilizing exhaust gas from the turbine for generating the cracking temperature. 7. The method of claim 6, wherein the exhaust gas of the turbine is used for drying fresh biomass. 8. The method of claim 6, wherein the exhaust gas of the turbine is used for heat introduction in a thermal oil circulation which produces the cracking temperature. 9. The method of claim 1, wherein the biomass is a biological waste material. 10. The method of claim 9, wherein the biological waste material is a residue of a material selected from the group consisting of sugar beet, rapeseed, and wood. 11. The method of claim 1, further comprising the step of subjecting the biomass to ultrasound. 12. The method of claim 1, further comprising the step of heating the second portion of the liquid fraction. 13. Apparatus for thermal processing of biomass, comprising:a reservoir for accepting a biomass mixture;a transport device associated to an outlet of the reservoir;a receiving tank for heating the mixture to a cracking temperature to thereby trigger a catalytic cracking reaction;a mixing pump disposed downstream of the receiving tank to receive the mixture from the receiving tank;an intermediate tank having an outgassing chamber;an outgassing device accommodated in the intermediate tank;a distillation column disposed downstream of the intermediate tank;a feed line fluidly connecting an outlet of the mixer pump to the outgassing device;a return line extending between a lower part of the intermediate tank and the receiving tank for returning a non-outgassed fraction of the mixture;a condenser fluidly connected to a top of the distillation column for cooling an outgassed vaporized fraction of the mixture to thereby produce fuel, said condenser having an outlet for discharge of the fuel; anda bypass having a bypass pump and extending between the lower part of the intermediate tank and the outgassing chamber of the intermediate tank, said bypass having a port in communication with an outlet of the transport device for introduction of biomass. 14. The apparatus of claim 13, further comprising a processing device, disposed downstream of the outlet of the condenser, for dewatering the fuel. 15. The apparatus of claim 14, wherein the processing device is a centrifuge. 16. The apparatus of claim 13, further comprising a storage tank fluidly connected to the condenser for receiving fuel. 17. The apparatus of claim 13, wherein the receiving tank has a double- jacketed configuration for circulation of hot thermal oil. 18. The apparatus of claim 17, wherein the thermal oil has a temperature adjusted to closely reach the cracking temperature. 19. The apparatus of claim 17, wherein the receiving tank is part of a circulation system for the thermal oil, said circulation system further including a heat exchanger. 20. The apparatus of claim 16, further comprising a turbine receiving fuel from the storage tank. 21. The apparatus of claim 20, wherein the receiving tank is part of a circulation system for the thermal oil, said circulation system further including a heat exchanger, said turbine producing exhaust gas for conduction to the heat exchanger. 22. The apparatus of claim 20, further comprising a generator operatively connected to the turbine. 23. The apparatus of claim 22, wherein the generator is connected to the public power grid. 24. The apparatus of claim 13, further comprising an ultrasound device disposed between the reservoir and the transport device for exposing the biomass mixture to ultrasound before undergoing the cracking reaction. 25. The apparatus of claim 13, wherein the biomass mixture includes at least one material selected from the group consisting of biocatalyst and biological residue. 26. The apparatus of claim 13, further comprising a heating unit disposed in the bypass. 27. The apparatus of claim 13, wherein the bypass pump is disposed upstream of the port. 28. The apparatus of claim 26, wherein the heating unit communicates with a circulation system of hot thermal oil for receiving heat energy from the thermal oil. 29. The apparatus of claim 13, wherein the mixing pump is formed as a heating device for generating substantially the cracking temperature and for subjecting the mixture to a further cracking reaction.
05/20/2008 00:00:00
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5. Combinations

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Combinations of mechanical methods: two consecutive methods as examples and integraded methods as separate technologies. 


5.1 Electro Acoustic Dewatering press (EAD press)

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The EAD press applies a combination of mechanical pressure, electrical current and ultrasonics. [\[Art. #ARTNUM\]](#article-96250-1991746824) **Highlights:** * The Department of Energy, Battelle Institute, and Ashbrook-Simon-Hartley, have jointly developed an Electro Acoustic Dewatering press (EAD press).  \[...\] This press is utilized after conventional dewatering devices and can **remove up to 50% water** from filtered sludge cake at a fraction of the cost incurred in existing thermal drying devices. \[...\] The EAD press has been tested successfully on a variety of materials including **apple pomace, corn gluten, sewage sludge, and coal fines**. A three week long full scale trial was conducted successfully at a pharmaceutical industry to determine the application of this technology for dewatering **waste activated sludge.** [\[Art. #ARTNUM\]](#article-96250-1991746824) * Published 1992 * In this study, we consider two treating methods: ultrasonic pre-treatment, which uses ultrasonic treatment as sludge pre-treatment before electro-osmosis dehydration, and ultrasonic coupling, which uses ultrasonic and electric fields simultaneously. \[...\] Under the same conditions, i.e. 2 cm cake initial thickness, voltage of 60 V for 5 min, and 0.1 MPa mechanical pressure for 5.5 min, the optimum processing conditions for ultrasonic pre-treatment were found to be 0.510 W/cm2 and 3.5 min, the **dehydration rate reached 34.71%**, and the optimum conditions for ultrasonic coupling were 0.255 W/cm2 and 3.5 min, while the dehydration rate reached **40.78%**. [\[Art. #ARTNUM\]](#article-96250-2616059255) * Published 2017 * An electroacoustic dewatering (EAD) technology has been developed in recent years that indicates good economic potential and an effectiveness that exceeds most conventional methods of dewatering. Very good results have been obtained from laboratory studies using the techniques with **fine coal slurries, food products, municipal sewage sludges**, and many other products.[ \[Art. #ARTNUM\]](#article-96250-2087875285) * Published 1988 **Patents:** * This method is applicable to food and pharmaceutical products \[...\] A method of dewatering an aqueous suspension by concurrently subjecting the aqueous suspension to the action of a **sonic or ultrasonic field and an electrical field** so as to remove the water from the suspension. \[...\] The method of claim 1 including applying a **pressure** differential to the portion of the suspension having an increased concentration of water whereby water removal is augmented [\[Art. #ARTNUM\]](#article-96250-US4561953) * Patent Battelle Memorial Institute Inc (1985, expired) * The invention relates to an ultrasonic wave, electroosmotic and mechanical pressure filter coupling sludge dewatering method \[...\] sludge dewatering rate and dewatering effect are improved, and the dewatering **energy consumption is reduced**[ \[Art. #ARTNUM\]](#article-96250-2976845438) * Chinese patent (2019) * Said equipment includes a mechanical filter pressing device, an ultrasonic quality-improving device, a pressure synergistic electroosmosis dehydration device and an adsorption dehydration material device.[ \[Art. #ARTNUM\]](#article-96250-2855493851) * Chinese patent (2009)

5.1.1 Electro Acoustic Dewatering press (EAD press)
ACOUSTIC AND ELECTROACOUSTIC METHODS OF DEWATERING AND DRYING
ABSTRACT Interesting results have been observed in applying acoustic energy to dewatering and drying materials. However, drying by acoustic energy alone is expensive, energy intensive, and at best can be justified only in applications where rapid drying is necessary to preserve a product, the product is heat sensitive and its value justified the cost. However, synergistic effects have been observed when acoustic energy has been used with electrophoresis and electro-osmosis to dewater materials. An electroacoustic dewatering (EAD) technology has been developed in recent years that indicates good economic potential and an effectiveness that exceeds most conventional methods of dewatering. Very good results have been obtained from laboratory studies using the techniques with fine coal slurries, food products, municipal sewage sludges, and many other products.
09/01/1988 00:00:00
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5.1.2 Electro Acoustic Dewatering press (EAD press)
Application of electro acoustics for dewatering pharmaceutical sludge
Application of electro acoustic principles for dewatering has been developed by Battelle Institute. The Department of Energy, Battelle Institute, and Ashbrook-Simon-Hartley, have jointly developed an Electro Acoustic Dewatering press (EAD press). The EAD press applies a combination of mechanical pressure, electrical current and ultrasonics. This press is utilized after conventional dewatering devices and can remove up to 50% water from filtered sludge cake at a fraction of the cost incurred in existing thermal drying devices. The dominant mechanism of sludge dewatering by EAD press is electro-osmosis due to the application of a direct current field. Electro-osmosis is caused by an electrical double layer of oppositely charged ions formed at the solid liquid interface, which is characterized by zeta potential. The ultrasonic fields help electro-osmosis by consolidation of the filter cake and by release of inaccessible liquid. The EAD press has been tested successfully on a variety of materials including apple pomace, corn gluten, sewage sludge, and coal fines. A three week long full scale trial was conducted successfully at a pharmaceutical industry to determine the application of this technology for dewatering waste activated sludge.
02/01/1992 00:00:00
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5.1.3 Electro Acoustic Dewatering press (EAD press)
Application of weak ultrasonic treatment on sludge electro-osmosis dewatering
ABSTRACTUltrasonic treatment is a good method of facilitating sewage sludge dewatering characteristics. It can also promote the potential of sludge electro-osmosis dewatering (EDW), which is an accepted method of deep dewatering, but the treatment method and optimizing conditions should be determined by performing experiments. In this study, we consider two treating methods: ultrasonic pre-treatment, which uses ultrasonic treatment as sludge pre-treatment before electro-osmosis dehydration, and ultrasonic coupling, which uses ultrasonic and electric fields simultaneously. Using sludge from the Tianjin Jizhuangzi sewage treatment plant, we analyze the influence of ultrasonic intensity and treatment time on sludge dewatering by performing two different methods. The results show that they effectively facilitated sludge EDW. Under the same conditions, i.e. 2 cm cake initial thickness, voltage of 60 V for 5 min, and 0.1 MPa mechanical pressure for 5.5 min, the optimum processing conditions for ultrasonic pre-t...
05/19/2018 00:00:00
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5.1.4 Electro Acoustic Dewatering press (EAD press)
Dewatering technology of mud and its device
The present invention relates to a sludge dehydration process and its equipment. Said equipment includes a mechanical filter pressing device, an ultrasonic quality-improving device, a pressure synergistic electroosmosis dehydration device and an adsorption dehydration material device. The cathode of the pressure synergistic electroosmosis dehydration device is placed at one side of sludge dehydration device, and its anode is placed at another side of sludge. Said ultrasonic quality-improving device is mainly composed of three portions of ultrasonic generator, ultrasonic convertor and ultrasonic contact. Besides, said invention also provides its working principle and concrete operation method and steps.
04/18/2007 00:00:00
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5.1.5 Electro Acoustic Dewatering press (EAD press)
Electro-Acoustic Dewatering (EAD) a Novel Approach for Food Processing, and Recovery
Abstract Separation of liquids from fine particle suspensions plays an important role in many industrial processes. In the past few years a number of technologies have been developed for the separation of slurries with coarse particle suspensions and intermediate particle sizes. However, separation of fine particles from their suspensions can be difficult and prohibitively costly. Battelle has developed a solid/liquid separation technology that utilizes differences in electro-kinetic and acoustic properties to enhance the efficiency of conventional solid/liquid separation techniques such as vacuum filters or presses. This method can dewater colloidal stable suspensions better than conventional techniques. Typical applications of this technology to food processing will be presented. Mechanisms involved during separation will also be discussed.
10/01/1988 00:00:00
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5.1.6 Electro Acoustic Dewatering press (EAD press)
Ultrasonic wave, electroosmotic and mechanical pressure filter coupling sludge dewatering device
The invention relates to an ultrasonic wave, electroosmotic and mechanical pressure filter coupling sludge dewatering method, which comprises the following steps: a sludge feeding stage: cathodicpressure filter plates (5), anode pressure filter plates (20) and a pressure filter cavity (8) are corresponded with each otherto form a plurality of pressure filter chambers; all the cathodic pressure filter plates are moved inwards under an action of a hydraulic system, and when the cathodicpressure filter platesare connected to a limiting position of the pressure filter cavity (8), all the anode pressure filter plates are moved to a feed port end of the pressure filter cavity; materials are injected into the feed port of all the pressure filter chambers through a feed pump to complete the sludgefeeding stage; and a dehydration stage: the cathodic pressure filter plates are connected withan ultrasonic transducer (19),and the ultrasonic transducer is connected with an ultrasonic generator through a lead wire; and all the cathodic pressure filter plates and the anode pressure filter plates are energized, an ultrasonic device starts to work, and the anode pressure filter platesare moved forwards in the hydraulic system, so that coupling filter press dehydration is achieved. By the adoption of the ultrasonic wave, electroosmotic and mechanical pressure filter coupling sludge dewatering method, sludge dewatering rate and dewatering effect are improved, and the dewatering energy consumption is reduced.
05/31/2019 00:00:00
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5.1.7 Electro Acoustic Dewatering press (EAD press)
Liquid separation process for suspensions by a pulsating electrical current
While the forms of the invention herein disclosed constitute presently preferred embodiments, many others are possible. It is not intended herein to mention all of the possible equivalent forms or ramifications of the invention. It is to be understood that the terms used herein are merely descriptive rather than limiting, and that various changes may be made without departing from the spirit or scope of the invention. __________________________________________________________________________ Electrical Electrical Ultrasonic Total Energy Per Sam- Mate- Vacuum Time Voltage Current Energy Energy Energy Pulse Pound of Initial Final % ple rial inches Minutes Volts mA W .multidot. Hr W .multidot. Hr W .multidot. Hr CPS Filtrate Solids Solids __________________________________________________________________________ 1 Hum. 15 14 0 0 0 0 0 0 0 18 18 2 Hum. 15 14 50 50.6 0.590 0 0.590 D.C. 17.8 18 38.5 3 Hum. 15 14 50 102.1 0.397 0 0.397 20 sec 12.0 18 32.0 on 40 sec off 4 Melc. 20 15 58 410 5.95 0 5.95 D.C. 108 8.8 38.25 5 Melc. 20 15 58 450 2.93 0 2.93 27 sec 57.8 8.8 44.5 on 33 sec off 6 Glut. 3-4 20 13 2500 10.83 0 10.83 D.C. 0.012 25.9 45.8 7 Glut. 2-3 18 20 3500 52.5 0 52.50 D.C. 0.0255 27 49.4 8 Glut. 2-3 20 20 3500 45.5 0 45.5 D.C. 0.031 27 48.9 9 Glut. 3-4 20 11 3000 5.49 0 5.49 100 0.0066 27 48.7 10 Glut. 3-4 20 11 2800 10.27 3.3 13.60 D.C. 0.0120 25.9 47.6 11 Glut. 2-3 20 15 2500 28.13 18.75 46.88 D.C. 0.0228 27 48.16 12 Glut. 2-3 20 20 3500 70.0 25.0 95.0 D.C. 0.040 27 49.1 13 Glut. 3-4 20 11 2800 5.13 8.33 13.46 100 0.0144 27 54.0 __________________________________________________________________________
1. A method of dewatering an aqueous suspension of melcone corn fiber slurry or corn gluten in a dewatering chamber with an inlet and discharge outlet, and having two electrodes, one of which is water permeable, forming opposing walls of the dewatering chamber, which method comprises: a. flowing the suspension into the dewatering chamber and between the two electrodes; b. applying a pulsating D.C. electrical field concurrently with step a between the two electrodes for at least about 15 minutes at a pressure of not more than about 20 inches of mercury, a voltage of at least about 58, a current of at least about 450 milliamperes, and a pulse cycle of about 27 seconds on and about 33 seconds off for a melcone suspension, and for at least about 20 minutes at a pressure of not more than about 4 inches of mercury, a voltage of at least about 11, a current of at least about 2.8 amperes, and a pulse cycle of about 0.01 second on and about 0.01 second off for a gluten suspension, to cause suspended particles to migrate away from the water permeable electrode and water toward the permeable electrode; c. concurrently with step b removing water from the suspension through the water permeable electrode; and d. removing the dewatered suspension from the dewatering chamber, whereby the total amount of energy employed for separating a unit of water from the suspension is less than would be required by use of a D.C. electrical field to separate the unit of water.
12/08/1986 00:00:00
Link to Patent
5.1.8 Electro Acoustic Dewatering press (EAD press)
Solid-liquid separation process for fine particle suspensions by an electric and ultrasonic field
This method is applicable to food and pharmaceutical products where thermal techniques cannot be used due to heat sensitivity and where valuable products soluble in water are left in the cake. Efficient recovery of the supernatant is possible by this technique. The method is further applicable to materials with characteristics similar to protein hydrolysates. ______________________________________ CERAMIC SLURRY Energy E U Total Moisture W.sub.R Vacuum (Watt (Watt (Watt Percent ML Sample (cm Hg) Hours) Hours) Hours) (Solids) Energy ______________________________________ 1 38 -- -- -- 55 -- 2 38 -- 4.17 4.17 54 -- 3 38 5 -- 5 56 0.18 4 38 4.17 -- 4.17 57 0.41 5 38 3.75 -- 3.75 58 0.68 6 38 3.17 -- 3.17 55.5 0.08 7 38 2.23 3.33 5.57 64 1.24 8 38 1.67 3.33 5.00 60 0.82 ______________________________________ ______________________________________ SEWAGE AND ANTIBIOTIC SLUDGE Energy E U Total Moisture W.sub.R Vacuum (Watt (Watt (Watt Percent ML Sample (cm Hg) Hours) Hours) Hours) (Solids) Energy ______________________________________ 1 38 -- -- -- 25.7 -- 2 38 3.60 -- 3.60 36 0.59 3 38 5.67 -- 5.67 34 0.32 4 38 5.5 5 10.5 45 0.31 ______________________________________ ______________________________________ PROTEIN HYDROLYSATE Vac- Energy uum E U Total Moisture W.sub.R Sam- (cm E (Watt (Watt (Watt Percent ML ple Hg) Volts Hours) Hours) Hours) (Solids) Energy ______________________________________ 1 38 -- -- -- -- 50 -- 2 38 -- -- -- -- 51 -- 3 38 -- -- 8.33 8.33 31.9 Negative 4 38 1 0.125 -- 0.125 53.2 12.1 5 38 5 1.04 -- 1.04 53 1.34 6* 38 3.5 0.245 2.917 3.16 61 1.62 7* 38 3.5 0.546 3.333 3.88 62 1.42 8 38 10 0.375 0.50 0.875 61.4 6.03 ______________________________________ *CaCl.sub.2 added.
1. A method of dewatering a suspension comprising: a. subjecting the suspension to an acoustical field at a frequency and amplitude adapted to cause separation in water bound to particles in the suspension; b. concurrently subjecting the suspension to an electrical field adapted to cause a migration of water and of particles resulting in a portion of the suspension having an increased concentration of particles and another portion having an increased concentration of water; and c. removing water from the portion of the suspension having an increased concentration of water. 2. The method of claim 1 including applying a pressure differential to the portion of the suspension having an increased concentration of water whereby water removal is augmented. 3. The method of claim 1 employing an amount of energy for separating a unit of water from the suspension, which amount is less than would be required by use of an acoustical field alone to separate the unit of water. 4. The method of claim 1 employing an amount of energy for separating a unit of water from the suspension, which amount is less than would be required by use of an electrical field alone to separate the unit of water. 5. The method of claim 1 which includes applying an acoustical field subsequent to the practice of claim 1. 6. The method of claim 1 employing an aqueous coal slurry for the aqueous suspension. 7. The method of claim 1 whereby the aqueous suspension is dewatered by concurrently subjecting it to an acoustical field and an electrical field whose power levels are approximately equal. 8. The method of claim 1 employing an aqueous ceramic slurry for the aqueous suspension. 9. The method of claim 1 employing an aqueous sewage and antibiotic sludge for the aqueous suspension. 10. The method of claim 1 employing an aqueous protein hydrolysate sludge for the aqueous suspension. 11. A method of dewatering an aqueous suspension comprising: a. flowing the suspension into a dewatering zone; b. subjecting the suspension to an acoustical field at an amplitude and frequency adapted to cause a separation of water bound to particles in the suspension; c. concurrently subjecting the suspension to an electrical field adapted to cause a migration of particles toward one portion of the zone and to cause a migration of water toward another portion of the zone; and d. removing water from the portion of the dewatering zone toward which water is migrating. 12. The method of claim 11 including applying a pressure differential at the portion of the zone toward which water is migrating whereby water removal is augmented. 13. The method of claim 11 employing an amount of energy for separating a unit of water from the suspension, which amount is less than would be required by use of an acoustical field alone to separate the unit of water. 14. The method of claim 11 employing an amount of energy for separating a unit of water from the suspension, which amount is less than would be required by use of an electrical field alone to separate the unit of water. 15. The method of claim 11 which includes applying an acoustical field subsequent to the practice of claim 11. 16. The method of claim 11 employing an aqueous coal slurry for the aqueous suspension. 17. The method of claim 11 whereby the aqueous suspension is dewatered by concurrently subjecting it to an acoustical field and an electrical field whose power levels are approximately equal. 18. The method of claim 11 employing an aqueous ceramic slurry for the aqueous suspension. 19. The method of claim 11 employing an aqueous sewage and antibiotic sludge for the aqueous suspension. 20. The method of claim 11 employing an aqueous protein hydrolysate sludge for the aqueous suspension. 21. A method of dewatering an aqueous suspension in a dewatering chamber with an inlet and discharge outlet, and having two electrodes, one of which is water permeable, forming opposing walls of the dewatering chamber which method comprises: a. flowing the suspension into the dewatering chamber and between the two electrodes; b. applying an acoustical field to the suspension at a frequency and amplitude adapted to separate water bound to suspended particles in the suspension; c. applying an electrical field concurrently with step b between the two electrodes adapted to cause the suspended particles to migrate away from the water permeable electrode and water toward the permeable electrode; d. concurrently with step c removing water from the suspension through the water permeable electrode; and e. removing the dewatered suspension from the dewatering chamber. 22. The method of claim 21 including applying a pressure differential to the portion of the suspension having an increased concentration of water whereby water removal is augmented. 23. The method of claim 21 employing an amount of energy for separating a unit of water from the suspension, which amount is less than would be required by use of an acoustical field alone to separate the unit of water. 24. The method of claim 21 employing an amount of energy for separating a unit of water from the suspension, which amount is less than would be required by use of an electrical field alone to separate the unit of water. 25. The method of claim 21 which includes a dewatering of the dewatered suspension by a subsequent applying of an acoustical field. 26. The method of claim 21 employing an aqueous coal slurry for the aqueous suspension. 27. The method of claim 21 whereby the aqueous suspension is dewatered by concurrently subjecting it to an acoustical field and an electrical field whose power levels are approximately equal. 28. The method of claim 21 wherein the applying of the acoustical field is at a frequency of about 5000 to 40,000 Hertz and at an amplitude of about 0.002 to 0.01 millimeters. 29. The method of claim 21 including adding a surface modifier to the slurry before or as the suspension is flowing into the dewatering chamber. 30. The method of claim 21 employing an aqueous ceramic slurry for the aqueous suspension. 31. The method of claim 21 employing an aqueous sewage and antibiotic sludge for the aqueous suspension. 32. The method of claim 21 employing an aqueous protein hydrolysate sludge for the aqueous suspension.
06/20/1984 00:00:00
Link to Patent

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