title: Stratification structure of polysaccharides and proteins in activated sludge with different aeration in membrane bioreactor.
abstract: The effect of distribution pattern of polysaccharides (PS) and proteins (PN) in activated sludge (AS) stratification with different aeration rates on membrane fouling and rejection efficiency were investigated. During high aeration, PN and PS concentrations increased in supernatant, the dominant fraction (84% of PN and 73% of PS) was small molecules (<1 kDa). Less slime and loose bound extracellular polymeric substances (LB-EPS), more tight bound EPS (TB-EPS) were observed compared with low aeration. The decrease in PN/PS ratio and Ca(2+) concentration within EPS deteriorated AS flocculation ability. At slow trans-membrane pressure (TMP) rise stage, fouling rate under high aeration was 41% lower than low aeration due to lower PN within EPS outer. Low PS rejection rate (about 23%) leaded to higher PS in effluent at this stage. High PS rejection rate (about 94%) at rapid TMP rise stage resulted in about 2.2-time higher fouling rate than that low aeration.
authors.affiliation: School of Chemistry Engineering, Northeast Dianli University, Jilin 132012, Jilin, PR China; Department of Civil and Environmental Engineering, Texas Tech University, 10th and Akron, Lubbock, TX 79409-1023, USA.
authors.forename: Haifeng
authors.initials: H
authors.lastname: Zhang
authors.affiliation: School of Chemistry Engineering, Northeast Dianli University, Jilin 132012, Jilin, PR China.
authors.forename: Haihuan
authors.initials: H
authors.lastname: Yu
authors.affiliation: School of Chemistry Engineering, Northeast Dianli University, Jilin 132012, Jilin, PR China.
authors.forename: Lanhe
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Department of Civil and Environmental Engineering, Texas Tech University, 10th and Akron, Lubbock, TX 79409-1023, USA. Electronic address: lianfa.song@ttu.edu.
authors.forename: Lianfa
authors.initials: L
authors.lastname: Song
mesh_terms: D019149:Bioreactors; D004868:Equipment Failure; D005427:Flocculation; D008567:Membranes, Artificial; D011134:Polysaccharides / Q000737:chemistry*; D011506:Proteins / Q000737:chemistry*; D012722:Sewage / Q000737:chemistry*; D014865:Waste Disposal, Fluid / Q000295:instrumentation* / Q000379:methods
chemical_list: D008567:Membranes, Artificial; D011134:Polysaccharides; D011506:Proteins; D012722:Sewage
keywords: Bioflocculation; Membrane bioreactor; Membrane fouling rate; Rejection rate; Stratification structure