State Environmental Protection Key Laboratory of Drinking Water Source Management and Technology, Shenzhen Academy of Environmental Science, Shenzhen, People's Republic of China.
Japan Research Center for Environmental Quality Management, Graduate School of Engineering, Kyoto University, Kyoto, Japan.
Environ Technol. 2024 Mar;45(7):1449-1458. doi: 10.1080/09593330.2022.2144467. Epub 2022 Nov 15.
This study characterized nitrogen removal and nitrous oxide (NO) emissions from lab-scale anoxic/aerobic sequencing batch reactor (AOSBR) and intermittent aeration sequencing batch reactor (IASBR), respectively, for treating synthetic municipal wastewater. The NO emission was evaluated in a simulated cycle, and batch conditions of aerobic nitrification, simultaneous nitrification and denitrification (SND), and aerobic denitrification. The results show that nitrogen removal was enhanced in IASBR compared to AOSBR, with 94.2% and 67.9% of total inorganic nitrogen removal efficiency in IASBR and AOSBR, respectively. In the simulated cycle, the emission factors (of oxidized ammonium) were 4.9% and 0.6% in AOSBR and IASBR, respectively. Under batch conditions, the NO emission factors during SND were obviously higher than that during aerobic nitrification and denitrification. The NO emission factors during SND ranging 0.68-11.68% in AOSBR and 1.25-5.13% in IASBR. Furthermore, NO emission under batch conditions was affected by the aeration ratios. Moderate and high aeration ratios used in this study stimulated the NO emission from SND. The NO emission was enhanced with the nitrite accumulation during aerobic nitrification when the nitrite-oxidizing bacteria was inhibited by a chemical inhibitor. Aerobic denitrification via nitrite could be the main pathway of NO generation from SND processes. The findings from our study can help further understand NO emission mechanisms and guide the optimization of the current wastewater treatment process for minimizing NO emission.
本研究分别以实验室规模的缺氧/好氧序批式反应器（AOSBR）和间歇曝气序批式反应器（IASBR）为对象，研究了处理合成城市污水时的脱氮和氧化亚氮（NO）排放特性。在模拟周期和好氧硝化、同步硝化反硝化（SND）和好氧反硝化的批式条件下，评估了 NO 排放。结果表明，与 AOSBR 相比，IASBR 中的氮去除率更高，分别为 94.2%和 67.9%。在模拟周期中，AOSBR 和 IASBR 的氧化铵排放因子（EOF）分别为 4.9%和 0.6%。在批式条件下，SND 过程中的 NO 排放因子明显高于好氧硝化和反硝化过程中的 NO 排放因子。AOSBR 和 IASBR 中的 SND 过程中，NO 排放因子分别为 0.68-11.68%和 1.25-5.13%。此外，批式条件下的 NO 排放受曝气比的影响。本研究中使用的中等和高曝气比会刺激 SND 过程中的 NO 排放。当硝化细菌被化学抑制剂抑制时，好氧硝化过程中硝态氮的积累会增强 NO 排放。通过亚硝酸盐进行好氧反硝化可能是 SND 过程中 NO 生成的主要途径。本研究的结果可以帮助进一步了解 NO 排放机制，并指导优化当前的废水处理工艺以最大限度地减少 NO 排放。
