title: [Non-nitrification pathway for NH4+ -N removal in pilot-scale drinking water biological processes].
abstract: The non-nitrification pathway for NH4+ -N removal in pilot-scale drinking water biological treatment processes and its possible mechanism were investigated through calculating N and DO stoichiometric balance. With more than 2 mg/L NH4+ -N in the influent, for the fluidized bed bioreactor (FBBR), the total of NH4+ -N, NO2(-) -N, NO3(-) -N in the influent was 0.91 mg/L higher than that in the effluent, and for the biofilter, its DO consumption was 2.90 mg/L less than the stoichiometric amount. The results suggested that nitrogen loss occurred in both reactors and a part of NH4+ -N was removed through non-nitrification pathway. Because the utilization of phosphorus and organic matters was independent of nitrogen loss, the assimilation and denitrification could be excluded from the possible mechanisms. Because the very low C/N in the influent and the accumulation of NO2(-) -N in the reactors were similar with the wastewater biological processes, the "autotrophic removal of nitrogen" was regarded as the most probable non-nitrification pathway. In this mechanism, the couple of short-cut nitrification and ANAMMOX (or OLAND) leading to the transformation of NH4+ -N and NO2(-) -N into gaseous N2 was responsible for the nitrogen loss in drinking water biological processes.
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093, China. xinyu@nju.edu.cn
authors.forename: Xin
authors.initials: X
authors.lastname: Yu
authors.forename: Lin
authors.initials: L
authors.lastname: Ye
authors.forename: Xu-dong
authors.initials: XD
authors.lastname: Li
authors.forename: Xiao-jian
authors.initials: XJ
authors.lastname: Zhang
authors.forename: Xu
authors.initials: X
authors.lastname: Shi
authors.forename: Bo
authors.initials: B
authors.lastname: Liu
authors.forename: Rui-hua
authors.initials: RH
authors.lastname: Li
mesh_terms: D000641:Ammonia / Q000302:isolation & purification* / Q000378:metabolism; D001673:Biodegradation, Environmental; D019149:Bioreactors / Q000382:microbiology; D009584:Nitrogen / Q000302:isolation & purification* / Q000378:metabolism; D010865:Pilot Projects; D014874:Water Pollutants, Chemical / Q000302:isolation & purification* / Q000378:metabolism; D018508:Water Purification / Q000379:methods*; D014881:Water Supply / Q000032:analysis*
chemical_list: D014874:Water Pollutants, Chemical; D000641:Ammonia; D009584:Nitrogen