title: Influence of wastewater sludge treatment using combined peroxyacetic acid oxidation and inorganic coagulants re-flocculation on characteristics of extracellular polymeric substances (EPS).
abstract: Extracellular polymeric substances (EPS) are highly hydrated biopolymers and play important roles in bioflocculation, floc stability, and solid-water separation processes. Destroying EPS structure will result in sludge reduction and release of trapped water. In this study, the effects of combined process of peracetic acid (PAA) pre-oxidation and chemical re-flocculation on morphological properties and distribution and composition of EPS of the resultant sludge flocs were investigated in detail to gain insights into the mechanism involved in sludge treatment. It was found that sludge particles were effectively solubilized and protein-like substances were degraded into small molecules after PAA oxidation. A higher degradation of protein-like substances was observed at acid environments under PAA oxidation. Microscopic analysis revealed that no integral sludge floc was observed after oxidation with PAA at high doses. The floc was reconstructed with addition of inorganic coagulants (polyaluminium chloride (PACl) and ferric chloride (FeCl3)) and PACl performed better in flocculation due to its higher charge neutralization and bridging ability. Combined oxidative lysis and chemical re-flocculation provide a novel solution for sludge treatment.
authors.affiliation: School of Environmental Studies, China University of Geosciences, Wuhan 430074, Hubei, China. Electronic address: zhwj_1986@126.com.
authors.forename: Weijun
authors.initials: W
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
authors.forename: Bingdi
authors.initials: B
authors.lastname: Cao
authors.affiliation: School of Environmental Studies, China University of Geosciences, Wuhan 430074, Hubei, China; State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China. Electronic address: wgds@rcees.ac.cn.
authors.forename: Dongsheng
authors.initials: D
authors.lastname: Wang
authors.affiliation: School of Environmental Studies, China University of Geosciences, Wuhan 430074, Hubei, China.
authors.forename: Teng
authors.initials: T
authors.lastname: Ma
authors.affiliation: School of Environmental Studies, China University of Geosciences, Wuhan 430074, Hubei, China.
authors.forename: Hua
authors.initials: H
authors.lastname: Xia
authors.affiliation: School of Chemistry and Environmental Engineering, Wuhan Institute of Technology, 430073 Hubei, China.
authors.forename: Dehong
authors.initials: D
authors.lastname: Yu
mesh_terms: D001419:Bacteria / Q000378:metabolism; D001704:Biopolymers / Q000737:chemistry*; D005427:Flocculation; D006863:Hydrogen-Ion Concentration; D010084:Oxidation-Reduction; D010463:Peracetic Acid / Q000737:chemistry*; D012722:Sewage / Q000737:chemistry*; D014865:Waste Disposal, Fluid / Q000379:methods*; D062065:Wastewater / Q000032:analysis; D014874:Water Pollutants, Chemical / Q000737:chemistry*
chemical_list: D001704:Biopolymers; D010463:Peracetic Acid; D012722:Sewage; D062065:Wastewater; D014874:Water Pollutants, Chemical
keywords: Activated sludge; Chemical flocculation; EPS; Oxidation; Peracetic acid