title: Influence of Silver nanoparticles on nutrient removal and microbial communities in SBR process after long-term exposure.
abstract: The widespread utilization of silver nanoparticles (AgNPs) in industrial and commercial products inevitably raises the release into wastewater that might cause potential negative impacts on sewage treatment system. In this paper, long-term exposure experiments at four levels were conducted to determine whether AgNPs caused adverse impacts on nutrient removals in sequencing batch reactors (SBRs) and changes of microbial community structure. Compared with the control reactor (without AgNPs), carbon, nitrogen and phosphorus removal in presence of 0.1mg/L AgNPs was no difference. However, presence of 1.0 and 10mg/L AgNPs decreased the average removal efficiencies of COD from 95.4% to 85.2% and 68.3%, ammonia nitrogen from 98.8% to 71.2% and 49%, SOP from 97.6% to 75.5% and 54.1%, respectively. It was found that AgNPs could accumulate in sludge with the distribution coefficients of 39.2-114L/g, inhibit the protein and polysaccharide production in EPS, reduce the SOUR of sludge, and greatly increase LDH release from microbial cells. The illumina high-throughput sequencing results indicated that AgNPs concentration changed the structures of bacterial communities, associating with the effects of AgNPs on reactor performance. Sequence analyses showed that Proteobacteria, Bacteroidetes and Acidobacteria were the dominant phyla. It was notable that AgNPs addition reduced the contents of several nitrifying bacteria at genera level in sludge, leading to the lower removal of nitrogen.
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, No73, Huanghe Road, Nangang District, Harbin 150090, China; Heilongjiang River Fisheries Research Institute, Chinese Academy of Fishery Sciences, No 43, Songfa Street, Daoli District, Harbin 150001, China.
authors.forename: Zhaohan
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, No73, Huanghe Road, Nangang District, Harbin 150090, China. Electronic address: hitzzh@hit.edu.cn.
authors.forename: Peng
authors.initials: P
authors.lastname: Gao
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, No73, Huanghe Road, Nangang District, Harbin 150090, China.
authors.forename: Moqing
authors.initials: M
authors.lastname: Li
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, No73, Huanghe Road, Nangang District, Harbin 150090, China.
authors.forename: Jiaqi
authors.initials: J
authors.lastname: Cheng
authors.affiliation: Heilongjiang River Fisheries Research Institute, Chinese Academy of Fishery Sciences, No 43, Songfa Street, Daoli District, Harbin 150001, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, No73, Huanghe Road, Nangang District, Harbin 150090, China. Electronic address: yujief@hit.edu.cn.
authors.forename: Yujie
authors.initials: Y
authors.lastname: Feng
mesh_terms: D057919:Biological Oxygen Demand Analysis; D019149:Bioreactors / Q000382:microbiology; D053768:Metal Nanoparticles; D064307:Microbiota; D009584:Nitrogen / Q000378:metabolism; D010758:Phosphorus / Q000378:metabolism; D012722:Sewage / Q000032:analysis; D012834:Silver / Q000378:metabolism* / Q000494:pharmacology; D013997:Time Factors; D014865:Waste Disposal, Fluid
chemical_list: D012722:Sewage; D010758:Phosphorus; D012834:Silver; D009584:Nitrogen
keywords: Inhibitory mechanisms; Microbial community structure; Nutrient removal; Silver nanoparticles; Wastewater treatment