title: Genetic associations as indices of nitrogen cycling rates in an aerobic denitrification biofilter used for groundwater remediation.
abstract: An aerobic denitrification biofilter (ADB) for groundwater remediation was developed with high removal efficiencies (total nitrogen (TN): 82.3-95.8%; NO3(-)-N: 93.2-98.2%). Nitrate (NO3(-)-N) transformation rates stabilized between 21.0 and 23.4 g/(m(3) h), whereas nitrite (NO2(-)-N) and ammonium (NH4(+)-N) transformation rates remained less than 6.0 g/(m(3) h) as the dissolved oxygen (DO) level increased from 1.0 mg/L to 6.0 mg/L. Nitric oxide (NO) and nitrous oxide (N2O) accumulated with great fluctuations (NO: 0-1.6×10(-3) g/(m(3) h); N2O: 0.1-1.1g/(m(3)h)) throughout the experiment. This study suggested that gene associations reflect quantitative relationships with aerobic denitrification rates and can provide useful information regarding aerobic denitrification processes in groundwater. Especially, the qnorB/nosZ ratio acts as the main driver for NO3(-)-N and NH4(+)-N transformation, while the qnorB/nosZ ratio followed by the (nirS+nirK)/nosZ ratio serve a dominant role in the accumulation of N2O and NO.
authors.affiliation: Key Laboratory of Water and Sediment Sciences, Ministry of Education, Department of Environmental Engineering, Peking University, Beijing 100871, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhang
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: Key Laboratory of Water and Sediment Sciences, Ministry of Education, Department of Environmental Engineering, Peking University, Beijing 100871, China.
authors.forename: Rongjing
authors.initials: R
authors.lastname: Wang
mesh_terms: D000332:Aerobiosis; D064751:Ammonium Compounds / Q000378:metabolism; D058440:Denitrification / Q000235:genetics*; D052918:Environmental Restoration and Remediation / Q000295:instrumentation / Q000379:methods*; D060587:Groundwater / Q000737:chemistry*; D009566:Nitrates / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism; D009573:Nitrites / Q000378:metabolism; D009584:Nitrogen / Q000032:analysis / Q000378:metabolism*; D009609:Nitrous Oxide / Q000378:metabolism; D010100:Oxygen / Q000378:metabolism; D018508:Water Purification / Q000379:methods*
chemical_list: D064751:Ammonium Compounds; D009566:Nitrates; D009573:Nitrites; D009569:Nitric Oxide; D009609:Nitrous Oxide; D009584:Nitrogen; D010100:Oxygen
keywords: Aerobic denitrification biofilter; Genetic association; Groundwater; Nitrogen cycling rates