title: Possible causes of excess sludge reduction adding metabolic uncoupler, 3,3',4',5-tetrachlorosalicylanilide (TCS), in sequence batch reactors.
abstract: Two parallel sequence batch reactors (SBRs) were operated, with and without TCS addition, to research the causes of sludge reduction by uncouplers. Three possible mechanisms of sludge reduction by TCS were studied: (1) occurrence of metabolic uncoupling, (2) consumption of more energy to resist the infection of TCS, (3) promotion of lysis-cryptic growth by TCS addition. Results showed the remarkable reduction of electronic transport system (ETS) activity and specific cellular ATP (SATP) in TCS reactor, which proved the occurrence of metabolic uncoupling. The increasing amounts of extracellular polymeric substances (EPS), as measured by chemical methods and excitation-emission matrix (EEM) fluorescence spectra, implied microorganisms consumed more energy to resist TCS. The similar DNA concentrations of the effluents in two reactors indicated sludge lysis was not intensified by TCS. Therefore, uncoupler might not only cause metabolic uncoupling but also induce more energy consumption in the production of some substances to resist uncoupler.
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, PR China.
authors.forename: Xiao-Chi
authors.initials: XC
authors.lastname: Feng
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, PR China. Electronic address: guowanqian@hit.edu.cn.
authors.forename: Wan-Qian
authors.initials: WQ
authors.lastname: Guo
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, PR China.
authors.forename: Shan-Shan
authors.initials: SS
authors.lastname: Yang
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, PR China.
authors.forename: He-Shan
authors.initials: HS
authors.lastname: Zheng
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, PR China.
authors.forename: Juan-Shan
authors.initials: JS
authors.lastname: Du
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, PR China.
authors.forename: Qu-Li
authors.initials: QL
authors.lastname: Wu
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, PR China. Electronic address: rnq@hit.edu.cn.
authors.forename: Nan-Qi
authors.initials: NQ
authors.lastname: Ren
mesh_terms: D001421:Bacteria, Anaerobic / Q000378:metabolism*; D061249:Batch Cell Culture Techniques / Q000295:instrumentation*; D019149:Bioreactors / Q000382:microbiology*; D004866:Equipment Contamination / Q000517:prevention & control; D004867:Equipment Design; D019544:Equipment Failure Analysis; D012458:Salicylanilides / Q000378:metabolism*; D012722:Sewage / Q000382:microbiology*; D014475:Uncoupling Agents / Q000378:metabolism*; D018508:Water Purification / Q000295:instrumentation*
chemical_list: D012458:Salicylanilides; D012722:Sewage; D014475:Uncoupling Agents; C003390:3,3',4',5-tetrachlorosalicylanilide
keywords: EPS; Electronic transport system activity; Metabolic uncoupler; Sludge reduction; TCS