title: Effect of solid retention time on membrane fouling in membrane bioreactor: from the perspective of quorum sensing and quorum quenching.
abstract: Solid retention time (SRT) is one of the most important operational parameters in membrane bioreactor (MBR), which significantly influences membrane fouling. It is widely recognized that SRT mainly changes biomass characteristics, and then, influences membrane fouling. Effect of SRT on quorum sensing (QS) in MBR, which could also influence fouling by coordinating biofilm formation, has not been reported. In this study, fouling, QS, soluble microbial products (SMP), and extracellular polymer substances (EPS) in MBRs operated under SRTs of 4, 10, and 40 days were investigated. The results showed that as SRT increased, the abundance of quorum quenching (QQ) bacteria increased, the quorum signal degradation activity of activated sludge increased, the concentrations of signal molecules in MBR decreased, the excretion of SMP and EPS decreased, and thus membrane biofouling was alleviated. Therefore, besides altering the biomass physiochemical properties, SRT also changed the balance between QS and QQ in MBR, and in this way, influenced membrane biofouling.
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), Harbin Institute of Technology, 73 Huanghe Road, Nangang District, Harbin, 150090, People's Republic of China.
authors.forename: Huarong
authors.initials: H
authors.lastname: Yu
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), Harbin Institute of Technology, 73 Huanghe Road, Nangang District, Harbin, 150090, People's Republic of China. xgr@hit.edu.cn.
authors.forename: Guoren
authors.initials: G
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), Harbin Institute of Technology, 73 Huanghe Road, Nangang District, Harbin, 150090, People's Republic of China.
authors.forename: Fangshu
authors.initials: F
authors.lastname: Qu
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), Harbin Institute of Technology, 73 Huanghe Road, Nangang District, Harbin, 150090, People's Republic of China.
authors.forename: Guibai
authors.initials: G
authors.lastname: Li
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), Harbin Institute of Technology, 73 Huanghe Road, Nangang District, Harbin, 150090, People's Republic of China. hitliangheng@163.com.
authors.forename: Heng
authors.initials: H
authors.lastname: Liang
mesh_terms: D001419:Bacteria / Q000254:growth & development*; D018407:Bacterial Physiological Phenomena; D019149:Bioreactors / Q000382:microbiology*; D008566:Membranes / Q000382:microbiology*; D053038:Quorum Sensing; D013997:Time Factors; D018508:Water Purification
keywords: Fouling; Membrane bioreactor (MBR); Quorum quenching (QQ); Quorum sensing (QS); Solid retention time (SRT)