title: Influence of extracellular polymeric substances (EPS) treated by combined ultrasound pretreatment and chemical re-flocculation on water treatment sludge settling performance.
abstract: Extracellular polymeric substances (EPS) are high molecular weight polymers and play a significant role in floc stability, floc size, bioflocculation and sludge settleability. The destruction and reconstruction of EPS improve the performance of solid-water separation processes. In this study, the influence of combined ultrasound pretreatment and chemical re-flocculation on the spatial distribution and composition of EPS was examined. Settleability efficiency demonstrated that the optimal operating condition was an ultrasound pretreatment time of 15 min at pH 6. Sludge particles were greatly disintegrated and the protein-like substances were converted into smaller molecules after ultrasound treatment, and pH had important effects on solubilization and degradation of protein-like substances. The flocs of sludge water after addition of polyacrylamide were larger in size and denser in structure than those resulting from addition of polyaluminium chloride. However, polyaluminium chloride had a better capacity for degrading EPS, especially at a dosage of 1.2 g/g total suspended solids. The results of this research show that the combination of ultrasonication and chemical re-flocculation is effective in treating sludge water from a drinking water treatment plant.
authors.affiliation: Key Laboratory of Integrated Regulation and Resource Development of Shallow Lakes, Hohai University, Nanjing 210098, China; College of Environment, Hohai University, Nanjing 210098, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Chen
authors.affiliation: College of Environment, Hohai University, Nanjing 210098, China.
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Gao
authors.affiliation: Key Laboratory of Integrated Regulation and Resource Development of Shallow Lakes, Hohai University, Nanjing 210098, China; College of Environment, Hohai University, Nanjing 210098, China. Electronic address: xuhang810826@163.com.
authors.forename: Hang
authors.initials: H
authors.lastname: Xu
authors.affiliation: College of Environment, Hohai University, Nanjing 210098, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Cai
authors.affiliation: College of Environment, Hohai University, Nanjing 210098, China.
authors.forename: Jianfeng
authors.initials: J
authors.lastname: Cui
mesh_terms: D002681:China; D005427:Flocculation; D008970:Molecular Weight; D011108:Polymers / Q000032:analysis* / Q000737:chemistry; D012722:Sewage / Q000737:chemistry*; D013010:Sonication; D014865:Waste Disposal, Fluid / Q000379:methods; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000737:chemistry; D018508:Water Purification / Q000379:methods*
chemical_list: D011108:Polymers; D012722:Sewage; D014874:Water Pollutants, Chemical
keywords: Extracellular polymeric substances (EPS); Settleability; Ultrasonication; Wastewater disposal; Water treatment sludge