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*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

5 Scopus citations


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 [rad]OH and the production of high-valent (Por)FeIV(O) intermediates. Synergistic effects of reactive oxygen species ([rad]OH, H2O2 and [Formula presented]/HO2) and (Por)FeIV(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.

Original languageEnglish
Article number112223
JournalEnvironmental Research
StatePublished - Mar 2022
Externally publishedYes


  • Advanced oxidation
  • Anaerobic digestion
  • Methane
  • Sodium iron chlorophyllin
  • Waste activated sludge


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