title: Contribution of stratified extracellular polymeric substances to the gel-like and fractal structures of activated sludge.
abstract: The gel-like and fractal structures of activated sludge (AS) before and after extracellular polymeric substances (EPS) extraction as well as different EPS fractions were investigated. The contributions of individual components in different EPS fractions to the gel-like behavior of sludge samples by enzyme treatment were examined as well. The centrifugation and ultrasound method was employed to stratify the EPS into slime, loosely and tightly bound EPS (LB- and TB-EPS). It was observed that all samples behaved as weak gels with weak-link. TB-EPS and AS after LB-EPS extraction showed the strongest elasticity in higher concentrations and highest mass fractal dimension, which may indicate the key role of TB-EPS in the gel-like and fractal structures of the sludge. Effects of protease or amylase on the gel-like property of sludge samples differed in the presence of different EPS fractions.
authors.affiliation: College of Environmental Science and Engineering, Beijing Key Lab for Source Control Technology of Water Pollution, Beijing Forestry University, Beijing 100083, China.
authors.forename: D Q
authors.initials: DQ
authors.lastname: Yuan
authors.affiliation: College of Environmental Science and Engineering, Beijing Key Lab for Source Control Technology of Water Pollution, Beijing Forestry University, Beijing 100083, China. Electronic address: wangyilimail@126.com.
authors.forename: Y L
authors.initials: YL
authors.lastname: Wang
authors.affiliation: College of Environmental Science and Engineering, Beijing Key Lab for Source Control Technology of Water Pollution, Beijing Forestry University, Beijing 100083, China.
authors.forename: J
authors.initials: J
authors.lastname: Feng
mesh_terms: D001704:Biopolymers; D017709:Fractals; D012212:Rheology; D012722:Sewage / Q000737:chemistry*
chemical_list: D001704:Biopolymers; D012722:Sewage
keywords: Activated sludge; Conceptual sludge model; Fractal structure; Gel-like structure; Stratified extracellular polymeric substances