title: Impact of sludge cation distribution pattern on its filterability in membrane bioreactor.
abstract: The distributions of cations of various valences (Na(+), Ca(2+) and Fe(3+)) in the outer layers of extracellular polymeric substances (EPSs) to pellet have a significant impact on the stratification structure of polysaccharides (PS) or proteins (PN) in activated sludge. Comparison with the control showed that the monovalent Na(+) reduced flocculability slightly (about 9.75%), whereas Ca(2+) and Fe(3+) increased flocculability significantly. The modified fouling index (MFI) had a significant correlation with PN in the supernatant (rp=0.8593), slime (rp=0.7218) and loosely bound EPS (LB, rp=0.8012). However, it had a moderate correlation with PS in supernatant (rp=0.5842), and weak correlation to slime (rp=0.3785) or LB (rp=0.3219). There was an ignored correlation with PN or PS in the tightly bound EPS (TB) or pellet. The lower amount of PN or PS in the supernatant would have positive impact on improving the activated sludge filterability.
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: Zhongping
authors.initials: Z
authors.lastname: Wang
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; D002412:Cations / Q000032:analysis*; D005374:Filtration / Q000379:methods*; D005427:Flocculation; D008567:Membranes, Artificial; D011134:Polysaccharides / Q000032:analysis; D011506:Proteins / Q000032:analysis; D012722:Sewage / Q000737:chemistry*; D014865:Waste Disposal, Fluid / Q000379:methods*
chemical_list: D002412:Cations; D008567:Membranes, Artificial; D011134:Polysaccharides; D011506:Proteins; D012722:Sewage
keywords: Bioflocculation; Extracellular polymeric substances; Filterability; Membrane bioreactor; Modified fouling index