Electro-dewatering of sewage sludge: Influence of combined action of constant current and constant voltage on performance and energy consumption

Xu, Qian; Zhou, Xin; Wu, Jiandong; Liu, Changyuan; Wei, Yijun; Liu, Jiangyan

doi:10.1016/j.scitotenv.2019.02.329

Cited by 28 publications

(7 citation statements)

References 38 publications

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“…They obtained up to 40-45% of dry substance content compared to 20-25% obtainable by conventional physical/mechanical processes [123]. This type of process can be applied in the sludge line, before or after the phase of stabilization, with very low energy consumption: 0.12-0.5 kWh kg water −1 for activated sludge and 0.14-0.55 kWh kg water −1 for digested sludge [124,125]. Moreover, other advantages, such as the removal of pathogens and reduction of the final transportation cost, can be highlighted [125].…”

Section: Electro-osmosismentioning

confidence: 99%

“…This type of process can be applied in the sludge line, before or after the phase of stabilization, with very low energy consumption: 0.12-0.5 kWh kg water −1 for activated sludge and 0.14-0.55 kWh kg water −1 for digested sludge [124,125]. Moreover, other advantages, such as the removal of pathogens and reduction of the final transportation cost, can be highlighted [125]. Therefore, the application of an electric field, combined with pressure, tends to increase the dehydration of the sludge.…”

Section: Electro-osmosismentioning

confidence: 99%

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What Advanced Treatments Can Be Used to Minimize the Production of Sewage Sludge in WWTPs?

et al. 2019

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Similar to other types of waste, sewage sludge (SS) must be minimized, not only to respect the European Directive 2018/851 on waste, but also because the cost of sludge management is approximately 50% of the total running costs of a wastewater treatment plant (WWTP). Usually, minimization technologies can involve sewage sludge production with three different strategies: (i) adopting a process in the water line that reduces the production of sludge; (ii) reducing the water content (dewatering processes) or (iii) reducing the fraction of volatile solids (stabilization). This review, based on more than 130 papers, aims to provide essential information on the process, such as the advantages, the drawbacks and the results of their application. Moreover, significant information on the technologies still under development is provided. Finally, this review reports a discussion on the impact of the application of the proposed processes in the sludge line on a WWTP with a capacity exceeding 100,000 population equivalent (PE).

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Section: Electro-osmosismentioning

confidence: 99%

Section: Electro-osmosismentioning

confidence: 99%

What Advanced Treatments Can Be Used to Minimize the Production of Sewage Sludge in WWTPs?

et al. 2019

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“…A simultaneous operation mode of pressure and electric dewatering (P/EDW sim ) is commonly used (Zhang et al 2017). However, the results from Lee et al (2002) and Qian et al (2019) showed that the water content of sludge was only reduced from 78-62% -68% based on P/EDW sim , failed to meet the requirement of sludge utilization. The low e ciency of P/EDW sim may due to the suppression of electroosmosis in electric dewatering by continuous pressure (Barton et al 1999).…”

Section: Introductionmentioning

confidence: 99%

Optimizing sludge dewatering with an alternate pressure and electric field

Xiao-hong

Wei

et al. 2021

Preprint

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Sludge dewatering is a prerequisite for the subsequent utilization of sludge. However, the existing mechanical dewatering cannot achieve satisfactory water content (< 60%). Herein, pressure and electric dewatering in alternate operation (P/EDWalt) was proposed to improve dewatering efficiency. Compared with conventional simultaneous mode, P/EDWalt performed better in sludge dewatering. Its optimal dewatering conditions were voltage of 30 V for 20 min in two electric dewaterings, and pressure of 0.04, 0.07 and 0.10 MPa in three pressure dewaterings. Such conditions, the water content of sludge was reduced from 83.7% to 53.3%, the dewatering efficiency was 36.3%, and the energy consumption was 0.138 kWh/kgtotal removed water. These phenomena such as electroosmosis, the ohmic heating and electrophoresis facilitated the removal of water in sludge, and the dewatered sludge has good reusability in incineration, landfill and agriculture. Therefore, P/EDWalt could serve as a promising method for the sludge dewatering.

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“…The main factors affecting EDW can be considered from the following two aspects: (1) the operating parameters such as pressure, 14 electric potential (or current density), 15,16 temperature, 17,18 cake thickness, 19 off-time interrupted, 20 sludge loading rate, 21 electrode congurations; 22 (2) the properties of sludge. The properties of sludge such as pH, conductivity, zeta potential and extracellular polymeric substances (EPS) are important because EDW is sensitive to their variations.…”

Section: Introductionmentioning

confidence: 99%