title: Effects of long-term addition of Cu(II) and Ni(II) on the biochemical properties of aerobic granules in sequencing batch reactors.
abstract: Copper (Cu(II)) and nickel (Ni(II)) are often encountered in wastewaters. This study investigated the individual toxic effects of long-term addition of Cu(II) and Ni(II) on the biochemical properties of aerobic granules in sequencing batch reactors (SBRs). The biochemical properties of aerobic granules were characterized by extracellular polymeric substances (EPS) content, dehydrogenase activity, microbial community biodiversity, and SBR performance. One SBR was used as a control system, while another two received respective concentration of Cu(II) and Ni(II) equal to 5 mg/L initially and increased to 15 mg/L on day 27. Results showed that the addition of Cu(II) drastically reduced the biomass concentration, bioactivity, and biodiversity of aerobic granules, and certainly deteriorated the treatment performance. The toxic effect of Ni(II) on the biodiversity of aerobic granules was milder and the aerobic granular system elevated the level of Ni(II) toxicity tolerance. Even at a concentration of 15 mg/L, Ni(II) still stimulated the biomass yield and bioactivity of aerobic granules to some extent. The elevated tolerance seemed to be owed to the concentration gradient developed within granules, increased biomass concentration, and promoted EPS production in aerobic granular systems.
authors.affiliation: Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Jinan, 250100, China.
authors.forename: Xin-Hua
authors.initials: XH
authors.lastname: Wang
authors.forename: Li-Hong
authors.initials: LH
authors.lastname: Gai
authors.forename: Xue-Fei
authors.initials: XF
authors.lastname: Sun
authors.forename: Hui-Jun
authors.initials: HJ
authors.lastname: Xie
authors.forename: Ming-Ming
authors.initials: MM
authors.lastname: Gao
authors.forename: Shu-Guang
authors.initials: SG
authors.lastname: Wang
mesh_terms: D000332:Aerobiosis; D001419:Bacteria / Q000187:drug effects / Q000378:metabolism*; D044822:Biodiversity; D018533:Biomass; D001704:Biopolymers / Q000378:metabolism; D019149:Bioreactors; D003300:Copper / Q000633:toxicity*; D009532:Nickel / Q000633:toxicity*; D010088:Oxidoreductases / Q000378:metabolism; D000644:Quaternary Ammonium Compounds / Q000378:metabolism
chemical_list: D001704:Biopolymers; D000644:Quaternary Ammonium Compounds; D003300:Copper; D009532:Nickel; D010088:Oxidoreductases