Pretreatment of sludge with sodium iron chlorophyllin-H2O2 for enhanced biogas production during anaerobic digestion

Zhen Li; Shuo Chen; Bingchuan Liu; Jiakuan Yang; Sha Liang; Keke Xiao; Jingping Hu; Huijie Hou

doi:10.1016/j.envres.2021.112223

Pretreatment of sludge with sodium iron chlorophyllin-H₂O₂ for enhanced biogas production during anaerobic digestion

Environ Res. 2022 Mar;204(Pt C):112223. doi: 10.1016/j.envres.2021.112223. Epub 2021 Oct 21.

Authors

Zhen Li¹, Shuo Chen¹, Bingchuan Liu¹, Jiakuan Yang², Sha Liang¹, Keke Xiao¹, Jingping Hu², Huijie Hou³

Affiliations

¹ School of Environmental Science and Engineering, Huazhong University of Science and Technology (HUST), Wuhan, 430074, PR China; Hubei Provincial Engineering Laboratory of Solid Waste Treatment, Disposal and Recycling, Wuhan, 430074, PR China.
² School of Environmental Science and Engineering, Huazhong University of Science and Technology (HUST), Wuhan, 430074, PR China; Hubei Provincial Engineering Laboratory of Solid Waste Treatment, Disposal and Recycling, Wuhan, 430074, PR China; State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology (HUST), Wuhan, 430074, PR China.
³ School of Environmental Science and Engineering, Huazhong University of Science and Technology (HUST), Wuhan, 430074, PR China; Hubei Provincial Engineering Laboratory of Solid Waste Treatment, Disposal and Recycling, Wuhan, 430074, PR China. Electronic address: houhuijie@hust.edu.cn.

PMID: 34688644
DOI: 10.1016/j.envres.2021.112223

Abstract

This study investigated a novel sodium iron chlorophyllin-H₂O₂ (SIC-H₂O₂) sludge pretreatment strategy before anaerobic digestion to enhance methane production. The efficiencies and mechanism of the proposed strategy to enhance sludge biodegradability were explored. The SIC-H₂O₂ pretreatment could enhance the oxidation performance for sludge floc disintegration to dissociate TB-EPS into S-EPS increased SCOD to 521.38 mg/L. The increase of solubilization and release of EPS with the pretreatment facilitate the biogas production at 702 L kg^-1 VS, which was 3-folds of the control and significantly higher than other pretreatments. The result of excitation-emission matrix and parallel factor (EEM-PARAFAC) analysis showed that the SIC-H₂O₂ pretreatment enhanced the dissociation of TB-EPS fractions, especially the protein-like and soluble microbial by-product-like substances. Electron paramagnetic resonance (EPR) results provided evidence for homolytic catalysis H₂O₂ for the generation OH and the production of high-valent (Por)Fe^IV(O) intermediates. Synergistic effects of reactive oxygen species (OH, H₂O₂ and /HO₂) and (Por)Fe^IV(O) enhanced the EPS disintegration during SIC-H₂O₂ pretreatment. The mixed-acid type fermentation provided continuous VFAs supply under the enrichment of Chloroflexi and Actinobacteria and multiplication Methanosaeta also promoted methane production. This research provides a feasible pretreatment strategy increase sludge biodegradability and enhance biogas production in the anaerobic digestion process.

Keywords: Advanced oxidation; Anaerobic digestion; Methane; Sodium iron chlorophyllin; Waste activated sludge.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Anaerobiosis
Biofuels* / analysis
Bioreactors
Chlorophyllides
Hydrogen Peroxide
Methane
Sewage* / microbiology
Waste Disposal, Fluid / methods

Substances

Biofuels
Chlorophyllides
Sewage
Hydrogen Peroxide
chlorophyllin
Methane