Application of Electroosmosis for Sludge Dewatering—A Review

Iwata, Masashi; Tanaka, Takanori; Jami, Mohammed Saedi

doi:10.1080/07373937.2012.691592

Cited by 78 publications

(18 citation statements)

References 91 publications

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“…However, the large specific surface area of cellulose nanocrystals means that the filtration resistance of the material is very high; the demands this makes on operation time and/or equipment size therefore limits the use of filtration. Electroosmotic dewatering is an assisted filtration technique that can be used to increase the solid content of suspensions of materials with charged surfaces (Iwata et al 2013;Mahmoud et al 2010). It has proved to be useful in increasing the solid content of cellulosic materials with high specific surface areas (Wetterling et al 2017a), such as microfibrillated cellulose suspensions (Heiskanen et al 2014), and has also shown potential for use in the dewatering of both biopolymers (Gözke and Posten 2010;Hofmann et al 2006;Hofmann and Posten 2003) and hydrogels (Tanaka et al 2014).…”

Section: Introductionmentioning

confidence: 99%

Electroosmotic dewatering of cellulose nanocrystals

et al. 2018

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One of the main challenges for industrial production of cellulose nanocrystals is the high energy demand during the dewatering of dilute aqueous suspensions. It is addressed in this study by utilising electroosmotic dewatering to increase the solid content of suspensions of cellulose nanocrystals. The solid content was increased from 2.3 up to 15.3 wt%, i.e. removal of more than 85% of all the water present in the system, at a much lower energy demand than that of thermal drying. Increasing the strength of the electric field increased not only the dewatering rate but also the specific energy demand of the dewatering operation: the electric field strength used in potential industrial applications is thus a trade-off between the rate of dewatering and the energy demand. Additionally, it was found that high local current intensity had the potential of degrading cellulose nanocrystals in contact with the anode. The maximum strength of the electric field applied should therefore be limited depending on the equipment design and the suspension conditions.

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Section: Introductionmentioning

confidence: 99%

Electroosmotic dewatering of cellulose nanocrystals

et al. 2018

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“…Raw sludge is often highly compressible, but mechanical dewatering is impeded by hydrodynamic resistance. [61,62] The mechanism of electroosmotic dewatering could be explained as a kind of consolidation; that is, a solid compressive pressure increases in the material under an electrical field, resulting in a decrease in the void volume of the material. Compared to conventional dewatering methods, electroosmotic dewatering can provide satisfactory results provided that it is preceded by mechanical dewatering, proper conditioning of the sludge is carried out, and optimum operational parameters are applied.…”

Section: Sludge Characterization Design and Managementmentioning

confidence: 99%

A Review of Dehydration of Various Industrial Sludges

Tunçal

Uslu

2014

Drying Technology

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Wastewater characteristics and sludge generation potential of point source categories are reviewed critically. Novel industryspecific sludge dewatering/drying solutions necessary to establish a sustainable model are examined through a detailed literature survey. Knowledge of sludge properties is one of the most critical issues needed to design dewatering/drying equipment. This study focuses on industrial wastewater/sludge characterization. In addition, a comprehensive review of current drying models and technologies is also presented. A summary of the results derived from a novel thin-filmbased photonic sludge dewatering/drying study is outlined as an alternative approach for industrial sludge control. Sludge was dried in a tubular quartz reactor (TQR), the inner surface of which was coated with a TiO 2 thin film. The TQR was irradiated with UV A, UV B, and UV C lamps. The consumed and generated energy fluxes through endergonic and exergonic reactions driven by photolysis and photocatalysis were investigated. In addition, the variations in sludge dewatering/drying characteristics were also examined and compared with conventional methods to evaluate the energy requirements.

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“…Consequently, for some years, researchers have started to intensify the existing mechanical processes by realizing convenient combinations, such as the addition of a thermal field, an acoustic field or an electric field (Smythe and Wakeman, 2000;Clayton et al, 2006;Couturier et al, 2007;Mahmoud et al, 2008Mahmoud et al, , 2010Mahmoud et al, , 2013Peteers, 2010;Tuan et al, 2012;Iwata et al, 2013). One of the most effective hybrid processes with regards to the improvement of wastewater sludge dewatering is electro-dewatering (EDW) which is the application of an electric field during the mechanical compression of the sludge (Mahmoud et al, 2010(Mahmoud et al, , 2011(Mahmoud et al, , 2013Tuan et al, 2012;Iwata et al, 2013;Olivier et al, 2014). Electrical phenomena used to improve the dewatering have been described in previous works (Mahmoud et al, 2010(Mahmoud et al, , 2013.…”

Section: Introductionmentioning

confidence: 99%

“…The change of the electrical properties of the sludge induced by the change of cake dryness also impacts the dewatering kinetics. In the literature, some correlations were proposed to link, for mineral suspensions, the filtrate flow rate and the electric current (Iwata et al, 2013). Among them, two equations can be helpful herein: the phenomenological flow rate equation (Eq.…”

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confidence: 99%