Enhancement of sludge dewaterability by electrolysis coupled with peroxymonosulfate oxidation process: Performance, mechanisms and implications

Junsen Wang; Tianrun Wang; Zonglin Li; Bomin Fu; Yuhui Zhai; Weijie Wang; Mudi Zhai; Jean-Marc Chovelon; Yuxiu Gong; Hongtao Wang

doi:10.1016/j.chemosphere.2022.135865

Enhancement of sludge dewaterability by electrolysis coupled with peroxymonosulfate oxidation process: Performance, mechanisms and implications

Chemosphere. 2022 Nov;307(Pt 2):135865. doi: 10.1016/j.chemosphere.2022.135865. Epub 2022 Aug 6.

Authors

Affiliations

¹ College of Environmental Science and Engineering, Key Laboratory of Yangtze River Water Environment, Ministry of Education, Tongji University, Siping Rd 1239, Shanghai, 200092, China.
² College of Environmental Science and Engineering, Key Laboratory of Yangtze River Water Environment, Ministry of Education, Tongji University, Siping Rd 1239, Shanghai, 200092, China; Shanghai Institute of Pollution Control and Ecological Security, UNEP-TONGJI Institute of Environment for Sustainable Development, Shanghai, 200092, China.
³ IRCELYON, CNRS UMR 5256, Université Claude Bernard Lyon 1, 2 Avenue Albert-Einstein, Villeurbanne, F-69626, France.
⁴ College of Environmental Science and Engineering, Key Laboratory of Yangtze River Water Environment, Ministry of Education, Tongji University, Siping Rd 1239, Shanghai, 200092, China; Shanghai Institute of Pollution Control and Ecological Security, UNEP-TONGJI Institute of Environment for Sustainable Development, Shanghai, 200092, China. Electronic address: hongtao@tongji.edu.cn.

PMID: 35944688
DOI: 10.1016/j.chemosphere.2022.135865

Abstract

With the rapid increase in waste activated sludge (WAS), it is urgent to develop appropriate dewatering processes to diminish sludge volume and improve disposal efficiency. In this study, an advanced oxidation process using electrolysis coupled with peroxymonosulfate (E/PMS) was applied to improve the dewaterability of WAS. The results indicated that the sludge water content (WC) and capillary suction time (CST) dropped from 98.4 ± 0.2% and 220.1 ± 2.3 s to 70.7 ± 0.8% and 63.0 ± 1.2 s, respectively, under the following conditions: an electrolysis voltage of 20 V, an electrolysis time of 20 min, and 200 mg/g TS PMS. The increase in sludge zeta potential, surface hydrophobicity, and flowability indicated a significant improvement in sludge dewaterability. SO₄^•-, O•H, and O₂1 generated in the E/PMS process were responsible for the improvement of WAS dewaterability. These reactive oxygen species damaged extracellular polymeric substances (EPS), decreased fluorescent EPS components, and transformed the extracellular protein secondary structures by influencing the H-bond actions that maintain the α-helix. The bound water content, and apparent viscosity of WAS were found to be reduced, which was also attributed to an increase in dewatering capacity. Additionally, E/PMS treatment enhanced the degradation of organic matter in sludge and reduced the toxicity of the filtrate as well as the bioavailability of heavy metals. The cost analysis found that the E/PMS process was relatively economical and has great potential for practical application.

Keywords: Dewaterability; Electrolysis; Extracellular polymeric substance; Peroxymonosulfate; Waste activated sludge.

MeSH terms

Electrolysis
Metals, Heavy*
Oxidation-Reduction
Peroxides
Reactive Oxygen Species
Sewage* / chemistry
Waste Disposal, Fluid / methods
Water / chemistry

Substances

Metals, Heavy
Peroxides
Reactive Oxygen Species
Sewage
Water
peroxymonosulfate