title: Coagulation increased the growth potential of various species bacteria of the effluent of a MBR for the treatment of domestic wastewater.
abstract: Microbial regrowth in reclaimed water is an important issue restricting water reclamation and reuse. Previous studies about the effect of coagulation on microbial growth in reclaimed water were limited and inconsistent. In this study, microbial growth potentials of the effluent of a membrane bioreactor (MBR) for the treatment of domestic wastewater after coagulation was evaluated by using bacteria of various phyla, classes (α-Proteobacteria, β-Proteobacteria, γ-Proteobacteria, and Actinobacteriaa) or species isolated from wastewater treatment plants (WWTPs) and assimilable organic carbon (AOC) test strains. Bacterial growth increased considerably after coagulation with polyaluminum for the samples investigated in this study. The results revealed that the microbial growth potentials in the effluent of the MBR evidently increased after coagulation. The increase ratio of bacterial growth could reach up to 929 %. Specific UV absorbance (SUVA) of the samples averagely decreased 16.3 %, but the removal efficiencies of the excitation emission matrices (EEMs) were less than 5 % after coagulation. It is suggested that the organic matter which affected the bacterial growth might be substances having aromaticity (i.e., UV254absorbance) but little fluorescence. According to molecular weight (MW) distribution analysis, the coagulation was indeed effective in removing organic matters with large MW. The removal of large MW organic matters might be related to bacterial growth increase. The results indicated that posttreatments are needed after coagulation to maintain the biological stability of reclaimed water.
authors.affiliation: Environmental Simulation and Pollution Control State Key Joint Laboratory, School of Environment, Tsinghua University, Beijing, 100084, People's Republic of China.
authors.forename: Tong
authors.initials: T
authors.lastname: Yu
authors.affiliation: Environmental Simulation and Pollution Control State Key Joint Laboratory, School of Environment, Tsinghua University, Beijing, 100084, People's Republic of China.
authors.forename: Guoqiang
authors.initials: G
authors.lastname: Li
authors.affiliation: China University of Mining and Technology, Beijing, 100083, People's Republic of China.
authors.forename: Wenqi
authors.initials: W
authors.lastname: Lin
authors.affiliation: Environmental Simulation and Pollution Control State Key Joint Laboratory, School of Environment, Tsinghua University, Beijing, 100084, People's Republic of China.|State Environmental Protection Key Laboratory of Microorganism Application and Risk Control, Graduate School at Shenzhen, Tsinghua University, Shenzhen, 518055, People's Republic of China.
authors.forename: Hong-Ying
authors.initials: HY
authors.lastname: Hu
authors.affiliation: Environmental Simulation and Pollution Control State Key Joint Laboratory, School of Environment, Tsinghua University, Beijing, 100084, People's Republic of China. luyun@tsinghua.edu.cn.
authors.forename: Yun
authors.initials: Y
authors.lastname: Lu
mesh_terms: D001419:Bacteria / Q000254:growth & development*; D019149:Bioreactors / Q000382:microbiology; D062065:Wastewater; D014867:Water / Q000032:analysis; D014874:Water Pollutants, Chemical / Q000032:analysis; D018508:Water Purification / Q000379:methods; D014881:Water Supply
chemical_list: D062065:Wastewater; D014867:Water; D014874:Water Pollutants, Chemical
keywords: Assimilable organic carbon (AOC); Biological stability; Coagulation; MBR; Microbial growth potential; Reclaimed water