Pressurised electro-osmotic dewatering of activated and anaerobically digested sludges: Electrical variables analysis

Citeau, Morgane; Olivier, Jérémy; Mahmoud, Akrama; Vaxelaire, Jean; Larue, O.; Vorobiev, Eugène

doi:10.1016/j.watres.2012.05.053

Cited by 86 publications

(37 citation statements)

References 19 publications

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“…2b one can see that current densities tend to decrease monotonically over time, due to the increase of sludge cake resistance next to the anode, with the progress of water removal (Citeau et al, 2012). This occurs more rapidly during the tests run with higher values of the electric potential and the current densities reach approximately the same values at the end of the tests, independently of the potential applied.…”

Section: Influence Of Sludge Digestionmentioning

confidence: 85%

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Performance of electro-osmotic dewatering on different types of sewage sludge

Visigalli

Turolla

Gronchi

et al. 2017

Environmental Research

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A B S T R A C TThe feasibility of pressure-driven electro-dewatering (EDW) on sludge samples taken after different biological processes, stabilisation methods or mechanical dewatering techniques was assessed. First, the influence of potential values on EDW of anaerobically and aerobically stabilised, mechanically dewatered, sludge samples was investigated. Preliminary tests carried out by applying a constant potential (10, 15 and 20 V) in a lab-scale device confirmed the possibility to reach a dry solid (DS) content of up to 42.9%, which corresponds to an increase of 15% of the dry content in dewatered sludge without the application of the electrical field. Dewatering increased with the applied potential but at the expense of a higher energy consumption. A potential equal to 15 V was chosen as the best compromise for EDW performance, in terms of DS content and energy consumption. Then, the influence of the mechanical dewatering was studied on aerobically stabilised sludge samples with a lower initial DS content: the higher initial water content led to a lower final DS content but with a considerable reduction of energy consumption. Finally, the biological process, studied by comparing sludge samples from conventional activated sludge and membrane bioreactor processes, didn't evidence any influence on EDW. Experimental results shown that DS obtained after mechanical dewatering, volatile solids and conductivity are the main factors influencing EDW. Anaerobically digested sludge reached the highest DS content, thanks to lower organic fraction.

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Section: Influence Of Sludge Digestionmentioning

confidence: 85%

“…Pressure-driven EDW procedure consisted of two successive stages: a preliminary filtration by applying pressure (t P =5 min) followed by the additional application of a potential at the selected operating voltage (t V =15 min), according to a procedure similar to that detailed by Citeau et al (2012).…”

Section: Pressure-driven Edw Testsmentioning

confidence: 99%

Performance of electro-osmotic dewatering on different types of sewage sludge

Visigalli

Turolla

Gronchi

et al. 2017

Environmental Research

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“…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). Using electroosmotic dewatering prior to drying can decrease the total energy demand of the dewatering operation (Larue et al 2006;Loginov et al 2013;Mahmoud et al 2011) and is therefore also attracting significant research interest in the treatment of wastewater sludge (Citeau et al 2012;Mahmoud et al 2011;Olivier et al 2015).…”

Section: Introductionmentioning

confidence: 99%

“…The anodes used for electrofiltration are often constructed from titanium meshes coated by either mixed metal oxides (Citeau et al 2012;Raats et al 2002) or noble metals (Rabie et al 1994;Saveyn et al 2006) in order to prevent corrosion (Larue et al 2003). The electrolysis reactions at the cathode are:…”

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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“…The process has been investigated in many publications, with a focus on the process performance and various operating parameters, such as pressure, electric potential, current, treatment time, delaying the application of the electric field, chemical conditioning dosage and cake thickness in the EDW cell [6,7,12,[15][16][17][18][19][20][21][22][23]. Citeau et al have shown that the use of a DC power supply at constant electric potential, instead of constant electric current, allows to achieve a higher DS content [20] and a better control of the temperature at the end of the tests, preventing from ohmic heating [17]. The EDW process has also been used as post-treatment to further dewater the sludge samples [8,11,14,[24][25][26].…”

Section: Introductionmentioning

confidence: 99%