title: N2O micro-profiles in biofilm from a one-stage autotrophic nitrogen removal system by microelectrode.
abstract: Emission of nitrous oxide (N2O), a greenhouse gas, is of growing concern in biological wastewater treatment. N2O emission from biofilm in a one-stage completely autotrophic nitrogen removal system was investigated using microelectrodes in this study. It is indicated that the pathways of nitrogen transformation in biofilm mainly included partial nitrification and anaerobic ammonium oxidation (anammox), also included nitrification and heterotrophic denitrification (HD). Ammonium-oxidizing bacteria (AOB) denitrification and HD were the main pathways resulting in N2O production in the biofilm, and hydroxylamine (NH2OH) oxidation was a subordinate pathway. In addition, the amount of N2O emission in test in which both NH4+and NO2-were added (NH4+-N: NO2--N = 1:1) was about 2 times greater than that in test with NH4+addition only. This result expressed that NO2-is an important factor affecting N2O production in the biofilm. In conclusion, the present study provides a theoretical support for reducing N2O production in one-stage completely autotrophic nitrogen removal system.
authors.affiliation: Key Laboratory of the Three Gorges Reservoir Region's Eco-Environments of MOE, Chongqing University, Chongqing 400045, China.
authors.forename: Xi-Xi
authors.initials: XX
authors.lastname: Wang
authors.affiliation: Key Laboratory of the Three Gorges Reservoir Region's Eco-Environments of MOE, Chongqing University, Chongqing 400045, China. Electronic address: fangfangcq@cqu.edu.cn.
authors.forename: Fang
authors.initials: F
authors.lastname: Fang
authors.affiliation: Key Laboratory of Reservoir Aquatic Environment of CAS, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China. Electronic address: ypchen@cigit.ac.cn.
authors.forename: You-Peng
authors.initials: YP
authors.lastname: Chen
authors.affiliation: Key Laboratory of Reservoir Aquatic Environment of CAS, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China.
authors.forename: Jin-Song
authors.initials: JS
authors.lastname: Guo
authors.affiliation: Key Laboratory of the Three Gorges Reservoir Region's Eco-Environments of MOE, Chongqing University, Chongqing 400045, China.
authors.forename: Kai
authors.initials: K
authors.lastname: Li
authors.affiliation: Key Laboratory of the Three Gorges Reservoir Region's Eco-Environments of MOE, Chongqing University, Chongqing 400045, China.
authors.forename: Han
authors.initials: H
authors.lastname: Wang
mesh_terms: D064751:Ammonium Compounds / Q000378:metabolism; D052818:Autotrophic Processes; D001421:Bacteria, Anaerobic / Q000378:metabolism; D018441:Biofilms; D019149:Bioreactors / Q000382:microbiology*; D058440:Denitrification; D019811:Hydroxylamine / Q000032:analysis; D058465:Nitrification; D009609:Nitrous Oxide / Q000032:analysis*; D010084:Oxidation-Reduction; D010100:Oxygen / Q000032:analysis; D012722:Sewage / Q000382:microbiology; D062065:Wastewater / Q000382:microbiology; D018508:Water Purification / Q000379:methods*
chemical_list: D064751:Ammonium Compounds; D019811:Hydroxylamine; D009609:Nitrous Oxide; D010100:Oxygen; D012722:Sewage; D062065:Wastewater
keywords: Biofilm; Micro-profiles; Nitrogen transformation; Nitrous oxide