title: Identifying sources of nitrous oxide emission in anoxic/aerobic sequencing batch reactors (A/O SBRs) acclimated in different aeration rates.
abstract: Both long term and batch experiments were carried out to identify the sources of the N(2)O emission in anoxic/aerobic sequencing batch reactors (A/O SBRs) under different aeration rates. The obtained results showed that aeration rate has an important effect on the N(2)O emission of A/O SBR and most of the N(2)O was emitted during the aerobic phase. During the anoxic phase, nitrate ammonification was the major source of N(2)O emission while denitrification performed as a sink of N(2)O, in all three bioreactors. The N(2)O emission mechanisms during the aerobic phase differed with the aeration rate. At low and high aeration rates (Run 1 and Run 3), both coupled-denitrification and nitrifier denitrification were ascribed to be the source of N(2)O emission. At mild aeration rate (Run 2), nitrifier denitrification by Nitrosomonas-like ammonia oxidizing-bacterial (AOB) was responsible for N(2)O emission while coupled-denitrification turned out to be a sink of N(2)O because of the presence of inner anaerobic region in sludge flocs.
authors: Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, 27 Shanda Nanlu, Jinan 250100, Shandong, PR China.
authors: Zhen
authors: Z
authors: Hu
authors: Jian
authors: J
authors: Zhang
authors: Huijun
authors: H
authors: Xie
authors: Shanping
authors: S
authors: Li
authors: Tingting
authors: T
authors: Zhang
authors: Jinhe
authors: J
authors: Wang
mesh_terms: D000332:Aerobiosis; D000693:Anaerobiosis; D001673:Biodegradation, Environmental; D019149:Bioreactors / Q000382:microbiology; D005798:Genes, Bacterial; D054892:Metagenome / Q000235:genetics; D009609:Nitrous Oxide / Q000032:analysis*; D010088:Oxidoreductases / Q000235:genetics; D010802:Phylogeny; D012722:Sewage / Q000737:chemistry; D014865:Waste Disposal, Fluid / Q000379:methods*
chemical_list: D012722:Sewage; D010088:Oxidoreductases; C022763:nitrous oxide reductase; C045582:ammonia monooxygenase; D009609:Nitrous Oxide