title: Enhanced long-term ammonium removal and its ranked contribution of microbial genes associated with nitrogen cycling in a lab-scale multimedia biofilter.
abstract: The multimedia biofilter achieved high and stable removal efficiencies for chemical oxygen demand (COD, 62-98%) and NH4(+) (68-98%) without costly aeration. Results revealed that lower CL (less than 13.9gCOD/m(3)d) and ACL (less than 2.8gNH4(+)-N/m(3)d) or a C/N ratio exceeding five was required to reduce NO3(-)-N accumulation and NO/N2O emission. Integrated analyses indicated that the coupling of simultaneous nitrification, anammox and denitrification processes (SNAD) were the primary reason accounted for the enhanced NH4(+)-N treatment performance. NH4(+)-N removal pathways can be ranked as follows: nitrification (amoA, archaeal) (54.6%)>partial denitrification (nirS, nirK) and anammox (37.8%)>anammox and partial denitrification (narG, napA) (12.6%). Specifically, NH4(+)-N removal was significantly inhibited by NO2(-)-N accumulation in the system (-21.6% inhibition). Results from stepwise regression analysis suggested that the NH4(+) removal rate was collectively controlled by amoA, archaeal, anammox, nirS, nirK, narG and napA.
authors.affiliation: Key Laboratory of Water and Sediment Sciences, Ministry of Education, Department of Environmental Engineering, Peking University, Beijing 100871, China.
authors.forename: Honglei
authors.initials: H
authors.lastname: Wang
authors.affiliation: Key Laboratory of Water and Sediment Sciences, Ministry of Education, Department of Environmental Engineering, Peking University, Beijing 100871, China. Electronic address: jiguodong@pku.edu.cn.
authors.forename: Guodong
authors.initials: G
authors.lastname: Ji
authors.affiliation: State Environmental Protection Key Laboratory of Wetland Ecology and Vegetation Restoration, School of Environment, Northeast Normal University, Changchun 130117, China.
authors.forename: Xueyuan
authors.initials: X
authors.lastname: Bai
mesh_terms: D000641:Ammonia / Q000378:metabolism; D064751:Ammonium Compounds / Q000302:isolation & purification*; D000693:Anaerobiosis; D001105:Archaea / Q000235:genetics / Q000378:metabolism; D001419:Bacteria / Q000235:genetics / Q000378:metabolism; D001673:Biodegradation, Environmental; D057919:Biological Oxygen Demand Analysis; D001711:Biotransformation; D058440:Denitrification; D005374:Filtration / Q000295:instrumentation*; D064351:Genes, Microbial; D007753:Laboratories; D058465:Nitrification; D009584:Nitrogen / Q000378:metabolism*; D058458:Nitrogen Cycle / Q000235:genetics*
chemical_list: D064751:Ammonium Compounds; D000641:Ammonia; D009584:Nitrogen
keywords: Biofilter; Functional gene; Nitrogen transformation; Path analysis; Quantitative relationship