Enhanced dewaterability of sewage sludge with zero-valent iron-activated persulfate oxidation system.

Abstract

The potential benefits of zero-valent iron-activated persulfate (Na2S2O8) oxidation in enhanced dewaterability of sludge, along with the associated mechanisms were investigated in this study. The sludge dewaterability was evaluated in terms of specific resistance to filtration (SRF) and water content. Based on these indexes, it was observed that ZVI-S2O8(2) oxidation effectively improved sludge dewaterability. The optimal conditions to give preferable dewaterability were found when the molar ratio of ZVI/S2O8(2-) was 5:1 and pH value was 3.0. The most important mechanism was proposed to be the degradation of extracellular polymeric substances (EPS) incorporated in sludge flocs and rupture of microbial cells. Three-dimensional excitation-emission matrix fluorescence spectra revealed that the powerful SO4- and ·OH generated from ZVI-S2O8(2-) system destroyed the particular functional groups of fluorescing substances (aromatic protein-like and tryptophan protein-like substances), resulting in the release of bound water and the subsequent enhancement of dewaterability. Therefore, ZVI/S2O8(2-) oxidation is an alternative approach showing great potential to be applied in sludge treatment plants.

• Authors: Lingling Hu, Yu Liao, Chun He, Wenqi Pan, Shangkun Liu, Yichang Yang, Shuzhen Li, Lianpeng Sun
• Journal: Water science and technology : a journal of the International Association on Water Pollution Research (Water Sci Technol) Vol. 72 Issue 2 Pg. 245-51 ( 2015) ISSN: 0273-1223 [Print] England
• PMID: 26177407 (Publication Type: Evaluation Study, Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Sewage
• Sulfides
• persulfides
• Iron

Topics

• Iron (chemistry)
• Oxidation-Reduction
• Refuse Disposal (methods)
• Sewage (chemistry)
• Sulfides (chemistry)