title: Effects of hexavalent chromium on performance and microbial community of an aerobic granular sequencing batch reactor.
abstract: The performance and microbial community of an aerobic granular sequencing batch reactor (GSBR) were investigated at different hexavalent chromium (Cr(VI)) concentrations. The COD and NH4 (+)-N removal efficiencies decreased with the increase in Cr(VI) concentration from 0 to 30 mg/L. The specific oxygen utilization rate (SOUR) decreased from 34.86 to 12.18 mg/(g mixed liquor suspended sludge (MLSS)·h) with the increase in Cr(VI) concentration from 0 to 30 mg/L. The specific ammonium oxidation rate (SAOR), specific nitrite oxidation rate (SNOR), and specific nitrate reduction rate (SNRR) decreased with the increase in Cr(VI) concentration, whereas the SNRR was always higher than the sum of SAOR and SNOR at 0-30 mg/L Cr(VI). The scanning electron micrographs (SEM) showed some undefined particles on the surface of filamentous bacteria that might be the chelation of chromium and macromolecular organics at 30 mg/L Cr(VI). The denaturing gradient gel electrophoresis (DGGE) profiles revealed that some microorganisms adapting to high Cr(VI) concentration gradually became the predominant bacteria, while others without Cr(VI)-tolerance capacity tended to deplete or weaken. Some bacteria could tolerate the toxicity of high Cr(VI) concentration in the aerobic GSBR, such as Propionibacteriaceae bacterium, Ochrobactrum anthropi, and Micropruina glycogenica.
authors.affiliation: Key Laboratory of Marine Environment and Ecology, Ministry of Education, Ocean University of China, Qingdao, 266100, China.
authors.forename: Zichao
authors.initials: Z
authors.lastname: Wang
authors.forename: Mengchun
authors.initials: M
authors.lastname: Gao
authors.forename: Zonglian
authors.initials: Z
authors.lastname: She
authors.forename: Chunji
authors.initials: C
authors.lastname: Jin
authors.forename: Yangguo
authors.initials: Y
authors.lastname: Zhao
authors.forename: Shiying
authors.initials: S
authors.lastname: Yang
authors.forename: Liang
authors.initials: L
authors.lastname: Guo
authors.forename: Sen
authors.initials: S
authors.lastname: Wang
mesh_terms: D000641:Ammonia / Q000378:metabolism; D001420:Bacteria, Aerobic / Q000187:drug effects / Q000378:metabolism*; D057919:Biological Oxygen Demand Analysis; D019149:Bioreactors; D002857:Chromium / Q000494:pharmacology*; D058645:Denaturing Gradient Gel Electrophoresis; D059013:Microbial Consortia; D009566:Nitrates / Q000378:metabolism*; D010084:Oxidation-Reduction; D012722:Sewage / Q000382:microbiology*; D013045:Species Specificity; D014865:Waste Disposal, Fluid / Q000379:methods*; D018508:Water Purification / Q000379:methods*
chemical_list: D009566:Nitrates; D012722:Sewage; D002857:Chromium; C074702:chromium hexavalent ion; D000641:Ammonia