title: The influence of chemically enhanced backwash by-products (CEBBPs) on water quality in the coagulation-ultrafiltration process.
abstract: This study was conducted to investigate the typical types of chemically enhanced backwash by-products (CEBBPs) produced in the chemically enhanced backwash (CEB) process and the influence of CEB parameters on typical CEBBPs in the coagulation-ultrafiltration process. Health risk assessment was applied to assess the potential adverse health effect from exposure to effluent after the optimal CEB. The results indicated that backwash reagent of sodium hypochlorite reacted with organic matter to produce CEBBPs, including 12 species of volatile halogenated organic compounds (VHOCs) and 9 species of haloacetic acids (HAAs) during CEB process. The amount of HAAs was higher than that of VHOCs indicating that the content of primary HAA precursor (hydrophilic organic matter) was high in raw surface water and the coagulation process could not lower the hydrophilic organic matter concentration. After comprehensive consideration of the influence of single factors on the CEBBP formation and membrane cleaning effect, the optimal CEB parameters was 4 min of backwash duration, 120 min of backwash interval, 20 L/(m(2)·h) of backwash flux, and 25 mg/L of reagent concentration. Under the optimum CEB cleaning parameters, the effluent did not pose non-carcinogenic risk to local residents but could pose potential carcinogenic risk.
authors.affiliation: School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072, China.
authors.forename: Yue
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072, China.|State Key Laboratory of Hydraulic Engineering Simulation and Safety, Tianjin University, Tianjin, 300072, China.
authors.forename: Xinhua
authors.initials: X
authors.lastname: Zhao
authors.affiliation: School of Environmental and Municipal Engineering, Tianjin Chengjian University, Tianjin, 300384, China.
authors.forename: Xinbo
authors.initials: X
authors.lastname: Zhang
authors.affiliation: School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072, China. tjdxhjzy@tju.edu.cn.
authors.forename: Jingmei
authors.initials: J
authors.lastname: Sun
mesh_terms: D014462:Ultrafiltration / Q000295:instrumentation / Q000379:methods*; D014867:Water / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000737:chemistry; D018508:Water Purification / Q000295:instrumentation / Q000379:methods*; D060753:Water Quality
chemical_list: D014874:Water Pollutants, Chemical; D014867:Water
keywords: CEB cleaning parameters; Chemically enhanced backwash by products (CEBBPs); Chemically enhanced blackwash (CEB); Coagulation-ultrafiltration process