title: [Effects of hydraulic retention time (HRT) on nitrification performance and microbial community of conventional activated sludge (CAS)].
abstract: A conventional activated sludge system was used to treat the ammonium-bearing inorganic wastewater for 260 days under decreased HRTs. When treating 500 mg x L(-1) NH4+ -N wastewater, over 98% ammonia removal could be obtained at HRT > or =20 h. Sharp washout of biomass occurred when HRT was further decreased, resulting in the accumulation of ammonium and nitrite. Changes in the community structure were monitored by microbial quinone and conventional analytical methods. Quinone profiles indicated that ammonia-oxidizing bacteria (AOB) in beta-Protevbacteria and Nitrobacteria in alpha-Proteobacteria were the predominant species to oxidize ammonia and nitrite, respectively. The number of AOB decreased with the reduction of biomass in bioreactor, while that of nitrite-oxidizing bacteria (NOB) changed little and fluctuated at 10(5) CFU x L(-1)
authors.affiliation: State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China. sdwhlhy@yahoo.com.cn
authors.forename: Hong-yan
authors.initials: HY
authors.lastname: Li
authors.forename: Yu
authors.initials: Y
authors.lastname: Zhang
authors.forename: Feng
authors.initials: F
authors.lastname: Gao
authors.forename: Tao
authors.initials: T
authors.lastname: Yu
authors.forename: Min
authors.initials: M
authors.lastname: Yang
mesh_terms: D044822:Biodiversity; D018533:Biomass; D019149:Bioreactors / Q000382:microbiology; D009576:Nitrobacter / Q000254:growth & development* / Q000378:metabolism*; D000644:Quaternary Ammonium Compounds / Q000378:metabolism*; D011803:Quinine / Q000378:metabolism; D012722:Sewage / Q000382:microbiology*; D013997:Time Factors; D014865:Waste Disposal, Fluid / Q000295:instrumentation / Q000379:methods*
chemical_list: D000644:Quaternary Ammonium Compounds; D012722:Sewage; D011803:Quinine