title: N₂O accumulation from denitrification under different temperatures.
abstract: The effects of temperature on nitrous oxide (N2O) accumulation during denitrification and denitritation were investigated. Batch experiments were performed to measure N2O accumulation at 25 and 35 °C. More N2O accumulation was observed during denitritation at the higher temperature as compared with full denitrification and low temperature tests. The highest nitrite concentration tested in this study (25 mg/L NO2 (-)N and pH 8.0) did not show inhibitory effect on N2O reduction. It was found that the major cause of more N2O accumulation during denitrification at higher temperature was due to higher N2O production rate and lower N2O solubility. Specific nitrate, nitrite, and N2O reduction rates increased 62, 61, and 41 %, respectively, when temperature rose from 25 to 35 °C. The decrease of N2O solubility in mixed liquor at 35 °C (when compared to 25 °C) resulted in faster diffusing rate of N2O from liquid to gas phase. It was also more difficult for gas phase N2O to be re-dissolved. The diffused N2O was then accumulated in the headspace, which was not available for denitrification by denitrifiers. The results of this study suggest higher temperature may worsen N2O emission from wastewater treatment plants (WWTPs).
authors.affiliation: Advanced Environmental Biotechnology Centre (AEBC), Nanyang Environment and Water Research Institute (NEWRI), Nanyang Technological University, 1 Cleantech Loop, CleanTech One, #06-08, Singapore, 637141, Singapore.|School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore.
authors.forename: Leong Soon
authors.initials: LS
authors.lastname: Poh
authors.affiliation: Advanced Environmental Biotechnology Centre (AEBC), Nanyang Environment and Water Research Institute (NEWRI), Nanyang Technological University, 1 Cleantech Loop, CleanTech One, #06-08, Singapore, 637141, Singapore.
authors.forename: Xie
authors.initials: X
authors.lastname: Jiang
authors.affiliation: DHI Water & Environment (S) Pte. Ltd., 1 Cleantech Loop, CleanTech One, #03-05, Singapore, 637141, Singapore.
authors.forename: Zhongbo
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Advanced Environmental Biotechnology Centre (AEBC), Nanyang Environment and Water Research Institute (NEWRI), Nanyang Technological University, 1 Cleantech Loop, CleanTech One, #06-08, Singapore, 637141, Singapore.|School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore.
authors.forename: Yu
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Advanced Environmental Biotechnology Centre (AEBC), Nanyang Environment and Water Research Institute (NEWRI), Nanyang Technological University, 1 Cleantech Loop, CleanTech One, #06-08, Singapore, 637141, Singapore. WJNg@ntu.edu.sg.|School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore. WJNg@ntu.edu.sg.
authors.forename: Wun Jern
authors.initials: WJ
authors.lastname: Ng
authors.affiliation: Advanced Environmental Biotechnology Centre (AEBC), Nanyang Environment and Water Research Institute (NEWRI), Nanyang Technological University, 1 Cleantech Loop, CleanTech One, #06-08, Singapore, 637141, Singapore. zhouyan@ntu.edu.sg.|School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore. zhouyan@ntu.edu.sg.
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhou
mesh_terms: D058440:Denitrification; D006863:Hydrogen-Ion Concentration; D009566:Nitrates / Q000378:metabolism; D009573:Nitrites / Q000378:metabolism; D009609:Nitrous Oxide / Q000032:analysis*; D010084:Oxidation-Reduction; D013696:Temperature; D062065:Wastewater / Q000737:chemistry* / Q000382:microbiology; D018508:Water Purification
chemical_list: D009566:Nitrates; D009573:Nitrites; D009609:Nitrous Oxide; D062065:Wastewater
keywords: Denitrification; Greenhouse gas; Nitrous oxide (N2O); Temperature; Wastewater treatment