Improvement of sludge electrodewatering by anode flushing

Citeau, Morgane; Loginov, Maksym; Vorobiev, Eugène

doi:10.1080/07373937.2015.1052083

Cited by 43 publications

(15 citation statements)

References 36 publications

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“…On average, DS f increased of 5.6% at 10 V, 10.8% at 15 V and 15.7% at 20 V. Potential values up to maximum 20 V and the cooling system (water jacket) have allowed keeping temperature below 30°C in the reactor at any process time, hindering the effect of joule heating on sludge viscosity and EDW results (Citeau et al, 2016).…”

Section: Influence Of Sludge Digestionmentioning

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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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: 99%

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

Visigalli

Turolla

Gronchi

et al. 2017

Environmental Research

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“…In this study, we observed severe corrosion on the stainless steel electrodes after they were operated in sludge with 0.15 M NaCl at 2 V/cm of DC for 4 h. In contrast, corrosion with AC power was insignificant, that only a few dents were found on the edge of electrodes with same experimental condition. The corrosion may become a critical obstacle for the applications of DC power in sludge treatment, as being addressed in other related studies ( Mahmoud et al, 2010 , Mahmoud et al, 2011 , Mahmoud et al, 2016 , Citeau et al, 2012 , Citeau et al, 2016 ). In addition, large amount of bubbles and foam were generated during DC treatment, and it may lead to operational issues in practice.…”

Section: Discussionmentioning

confidence: 97%

Sludge disinfection using electrical thermal treatment: The role of ohmic heating

Zhu

Hoffmann

Jiang

2018

Science of The Total Environment

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Electrical heating has been proposed as a potential method for pathogen inactivation in human waste sludge, especially in decentralized wastewater treatment systems. In this study, we investigated the heat production and E. coli inactivation in wastewater sludge using electrical thermal treatment. Various concentrations of NaCl and NH4Cl were tested as electrolyte to enhance conductivity in sludge mixtures. At same voltage input (18 V), sludge treated with direct current (DC) exhibited slower ascent of temperature and lower energy efficiencies for heat production comparing to that using alternate current (AC). However, DC power showed better performance in E. coli inactivation due to electrochemical inactivation in addition to thermal inactivation. Greater than 6log10 removal of E. coli was demonstrated within 2 h using 0.15 M of NaCl as electrolyte by AC or DC power. The heat production in sludge was modeled using Maxwell–Eucken and effective medium theory based on the effective electrical conductivity in the two-phase (liquid and solid) sludge mixtures. The results showed that the water and heat loss is a critical consideration in modeling of sludge temperature using ohmic heating. The experimental data also suggested that the models are less applicable to DC power because the electrochemical reactions triggered by DC reduce the concentration of NH4+ and other ions that serve as electrolyte. The results of this study contribute to the development of engineering strategies for human waste sludge management.

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“…The extent of the electrolysis reactions is highly influenced by the ionic species present and the materials of the electrodes . Corrosion is prevented by using “nonconsumable” electrodes made from either mixed-metal titanium meshes, entire graphite plates, or noble metals . The major reactions that occur are related to water electrolysis where M represents the material of the electrode and M n + represents its cation.…”

Section: Theorymentioning

confidence: 99%

“…39 Corrosion is prevented by using "nonconsumable" electrodes made from either mixed-metal titanium meshes, entire graphite plates, or noble metals. 43 The major reactions that occur are related to water electrolysis 44 where M represents the material of the electrode and M n+ represents its cation.…”

Section: Theorymentioning

confidence: 99%

Electroassisted Filtration of Microfibrillated Cellulose: Insights Gained from Experimental and Simulation Studies

Karna

Lidén

Wohlert

et al. 2021

Ind. Eng. Chem. Res.

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An electroassisted filtration technique has been employed to improve dewatering of a suspension of microfibrillated cellulose (MFC) produced via 2,2,6,6-tetramethylpiperidinyl-1-oxyl (TEMPO)-mediated oxidation. In addition, all-atom molecular dynamic (MD) simulations were performed to deepen the understanding of the complicated dewatering mechanism on a molecular level. Both the experimental and the simulation results implied that the dewatering rate was not only improved when electroassisted filtration was used but also found to be proportional to the strength of the electric field. A channeled dewatered structure was observed for these experiments and may have contributed to enhanced dewatering by providing high overall permeability. The MD simulations revealed that the electric field had a significant impact on the fibril movement, whereas the impact of pressure was limited. The simulations also suggested that the increased filtrate flow upon the application of an electric field was not only due to electroosmotic flow but also due to electrophoretic movement of the fibrils toward the anode that led to the release of water that had been trapped between the fibrils, allowing it to be pressed out together with the rest of the bulk water. This study shows that electroassisted filtration has the potential to improve the dewatering of TEMPO-MFC, and the MD simulations provide further insights into the dewatering mechanism.

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Improvement of sludge electrodewatering by anode flushing

Cited by 43 publications

References 36 publications

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

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

Sludge disinfection using electrical thermal treatment: The role of ohmic heating

Electroassisted Filtration of Microfibrillated Cellulose: Insights Gained from Experimental and Simulation Studies

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