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Impact of dissolved oxygen on the production of nitrous oxide in biological aerated filters

He, Qiang, Zhu, Yinying, Li, Guo, Fan, Leilei, Ai, Hainan, Huangfu, Xiaoliu, Li, Hong
Frontiers of environmental science & engineering 2017 v.11 no.6 pp. 16
Flavobacterium, Nitratifractor, biofilters, denaturing gradient gel electrophoresis, dissolved oxygen, greenhouse gas emissions, nitrification, nitrites, nitrous oxide, oxidation, polymerase chain reaction, wastewater
Polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) and microelectrode technology were employed to evaluate the Nitrous oxide (N₂O) production in biological aerated filters (BAFs) under varied dissolved oxygen (DO) concentrations during treating wastewater under laboratory scale. The average yield of gasous N₂O showed more than 4-fold increase when the DO levels were reduced from 6.0 to 2.0 mg∙L–¹, indicating that low DO may drive N₂O generation. PCR-DGGE results revealed that Nitratifractor salsuginis were dominant and may be responsible for N₂O emission from the BAFs system. While at a low DO concentration (2.0 mg∙L–¹), Flavobacterium urocaniciphilum might play a role. When DO concentration was the limiting factor (reduced from 6.0 to 2.0 mg∙L–¹) for nitrification, it reduced NO ₂ ⁻ -N oxidation as well as the total nitrification. The data from this study contribute to explain how N₂O production changes in response to DO concentration, and may be helpful for reduction of N₂O through regulation of DO levels.