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Author Spotlight: Understanding Riverine Nitrogen Impacts and Primary Productivity for Effective Nutrient Management
Published on: July 14, 2023
[N2O Generation, Key Influencing Factors, and Emission Reduction Strategies of A2O Process in Municipal Wastewater
Song-Qing Huang1, Xiu-Hong Liu1, Xin-Yue Cao1
1National Engineering Laboratory of Urban Sewage Advanced Treatment and Resource Utilization Technology, Faculty of Architecture, Civil and Transportation Engineering, Beijing University of Technology, Beijing 100124, China.
Abstract:
To achieve non-carbon dioxide greenhouse gas emission reduction and control in municipal wastewater treatment plants (WWTPs), this study conducted one-year long-term monitoring of nitrous oxide (N2O) in the anaerobic-anoxic-aerobic (A2O) process of a large-scale municipal wastewater treatment plant in Beijing. The experimental results showed that the anaerobic and anoxic zones of the A2O process could effectively remove dissolved N2O contained in the return sludge, while the aerobic zone was the main area for N2O generation and emission, and its generation pathway may have been dominated by ammonia oxidizing bacteria (AOB) denitrification. A significant difference was observed between winter and summer N2O production, and the difference in the average N2O release flux was up to 7.6 times, and the average monthly N2O emission in winter was 32.75 kg, which was significantly higher than that in summer (6.06 kg). The accumulation of nitrite (NO2--N) and the concentration of dissolved oxygen (DO) had a significant impact on N2O production. Therefore, to achieve N2O reduction in the A2O process, the concentration of NO2--N in the aerobic zone should be controlled below 0.40 mg·L-1 in winter and 0.10 mg·L-1 in summer, while the DO concentration should be maintained above 1.2 mg·L-1.
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