Tan Tan, Yang Yiming, Wang Xueying, Wu Tianxin, Zhang Lingxin, Yu Fengyuan, Li Jiawei, Sui Qianwen, Chen Meixue, Wei Yuansong
PowerChina Environmental Engineering Co. Ltd., Hangzhou, China.
PowerChina Road Bridge Group Co. Ltd., Beijing, China.
Water Environ Res. 2025 Jul;97(7):e70142. doi: 10.1002/wer.70142.
Wastewater treatment is a significant source of greenhouse gas (GHG) emissions, particularly methane (CH) and nitrous oxide (NO). Denitrification acts both as a source of NO emissions and a sink for its reduction, but the direct measurement of NO reduction to N remains a challenge. In this study, an assay method was developed to monitor GHG emissions by comparing denitrification and partial denitrification coupled with anammox (PD/A), with natural isotope analysis used to track NO transformation. The results showed that the PD/A process had a higher nitrogen removal rate and decreased NO emission by 94% compared to denitrification in the treatment of domestic sewage. Both PD/A and denitrification treatments exhibited similar CH emission factors at 0.06%. In the tests of synthetic wastewater prepared with sodium acetate, both PD/A and denitrification treatments demonstrated a two-fold increase in NO -N removal rates, along with a 67%-78% reduction in NO emissions and a 67%-83% reduction in CH emissions. Isotope analysis of NO indicated that PD/A exhibited a higher N site preference and greater NO reduction rates compared to denitrification, contributing to NO mitigation. The synergy of denitrifiers (Denitratisoma and Dechloromonas) and anammox bacteria (Candidatus Brocadia) enhanced nitrogen removal rates and reduced NO emissions.
废水处理是温室气体（GHG）排放的一个重要来源，尤其是甲烷（CH₄）和一氧化二氮（N₂O）。反硝化作用既是N₂O排放的一个来源，也是其还原的一个汇，但直接测量N₂O还原为N₂仍然是一个挑战。在本研究中，开发了一种测定方法，通过比较反硝化和厌氧氨氧化耦合的部分反硝化（PD/A）来监测温室气体排放，并使用天然同位素分析来追踪N₂O的转化。结果表明，在处理生活污水时，与反硝化相比，PD/A工艺具有更高的氮去除率，N₂O排放量降低了94%。PD/A和反硝化处理的CH₄排放因子相似，均为0.06%。在用乙酸钠制备的合成废水测试中，PD/A和反硝化处理的NO₃-N去除率均提高了两倍，同时N₂O排放量降低了67%-78%，CH₄排放量降低了67%-83%。对N₂O的同位素分析表明，与反硝化相比，PD/A表现出更高的N位点偏好性和更大的N₂O还原率，有助于减少N₂O排放。反硝化菌（脱氮索菌属和脱氯单胞菌属）和厌氧氨氧化菌（暂定布罗卡德氏菌属）的协同作用提高了氮去除率并减少了N₂O排放。
