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)

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)

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)

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)

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)

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)

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)

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)

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)

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)

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)

**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)

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)

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)

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)

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)

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)

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)

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)

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)

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)

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)

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)

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)

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)

**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)

**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)

**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)

**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)

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)

**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)

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)

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)

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)

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)

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)

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)

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)

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)

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)