title: Who contributes more to N2O emission during sludge bio-drying with two different aeration strategies, nitrifiers or denitrifiers?
abstract: Global warming effects have drawn more and more attention to studying all sources and sinks of nitrous oxide (N2O). Sludge bio-drying, as an effective sludge treatment technology, is being adopted worldwide. In this study, two aeration strategies (piles I and II) were compared to investigate the primary contributors to N2O emission during sludge bio-drying through studying the evolution of functional genes involved in nitrification (amoA, hao, and nxrA) and denitrification (narG, nirS, nirK, norB, and nosZ) by quantitative PCR (qPCR). Results showed that the profile of N2O emission can be divided into three stages, traditional denitrification contributed largely to N2O emission at stage I (days 1-5), but N2O emission mainly happened at stage II (days 5-14) due to nitrifier denitrification and NH2OH accumulation by ammonia-oxidizing bacteria (AOB), accounting for 51.4% and 58.2% of total N2O emission for piles I and II, respectively. At stage III (days 14-21), nitrifier denitrification was inhibited because sludge bio-drying proceeded mainly by the physical aeration, thus N2O emission decreased and changed little. The improved aeration strategy availed pile I to reduce N2O emission much especially at stages II and III, respectively. These results indicated that nitrifier denitrification by AOB and biological NH2OH oxidation due to AOB made more contribution to N2O emission, and aeration strategy was crucial to mitigate N2O emission during sludge bio-drying.
authors.affiliation: State Key Joint Laboratory of Environmental Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China.|University of Chinese Academy of Sciences, Beijing, 100049, China.
authors.forename: Junya
authors.initials: J
authors.lastname: Zhang
authors.affiliation: State Key Joint Laboratory of Environmental Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China.|University of Chinese Academy of Sciences, Beijing, 100049, China.
authors.forename: Yuanyue
authors.initials: Y
authors.lastname: Wang
authors.affiliation: State Key Joint Laboratory of Environmental Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China.|University of Chinese Academy of Sciences, Beijing, 100049, China.
authors.forename: Dawei
authors.initials: D
authors.lastname: Yu
authors.affiliation: State Key Joint Laboratory of Environmental Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China.|University of Chinese Academy of Sciences, Beijing, 100049, China.
authors.forename: Juan
authors.initials: J
authors.lastname: Tong
authors.affiliation: State Key Joint Laboratory of Environmental Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China.|University of Chinese Academy of Sciences, Beijing, 100049, China.
authors.forename: Meixue
authors.initials: M
authors.lastname: Chen
authors.affiliation: State Key Joint Laboratory of Environmental Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China.|University of Chinese Academy of Sciences, Beijing, 100049, China.
authors.forename: Qianwen
authors.initials: Q
authors.lastname: Sui
authors.affiliation: State Key Joint Laboratory of Environmental Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China.|University of Chinese Academy of Sciences, Beijing, 100049, China.
authors.forename: BuHe
authors.initials: B
authors.lastname: ChuLu
authors.affiliation: State Key Joint Laboratory of Environmental Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China. yswei@rcees.ac.cn.|University of Chinese Academy of Sciences, Beijing, 100049, China. yswei@rcees.ac.cn.
authors.forename: Yuansong
authors.initials: Y
authors.lastname: Wei
mesh_terms: D000388:Air; D001419:Bacteria / Q000235:genetics*; D018407:Bacterial Physiological Phenomena; D019149:Bioreactors / Q000382:microbiology; D058440:Denitrification / Q000235:genetics; D003890:Desiccation; D057232:Global Warming; D058465:Nitrification / Q000235:genetics; D009609:Nitrous Oxide / Q000032:analysis*; D010084:Oxidation-Reduction; D060888:Real-Time Polymerase Chain Reaction; D012722:Sewage / Q000737:chemistry / Q000382:microbiology*; D014835:Volatilization; D014865:Waste Disposal, Fluid
chemical_list: D012722:Sewage; D009609:Nitrous Oxide
keywords: N2O emission; Nitrifier denitrification; Nitrogen transformation functional genes; Quantitative PCR; Sludge bio-drying