Tan Xin, Nie Wen-Bo, Luo Kai, Lu Yang, Wang Xiao-Wei, Dang Cheng-Cheng, Liu Lu-Yao, Wang Xuan, Zhao Zhi-Cheng, Ren Nan-Qi, Xie Guo-Jun
State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, 150090, China.
Key Laboratory of the Three Gorges Region's Eco-Environment, Ministry of Education, College of Environment and Ecology, Chongqing University, Chongqing, 400044, China.
J Environ Manage. 2025 Sep;392:126759. doi: 10.1016/j.jenvman.2025.126759. Epub 2025 Jul 30.
Denitrifying anaerobic methane oxidation (DAMO) process uses methane produced by anaerobic digestion to remove nitrogen, contributing to sustainable operation of wastewater treatment. Fe(III), which is widely present in wastewater, has been shown to affect nitrogen metabolites of DAMO archaea, but its long-term effects on nitrogen removal performance and microbial community structure of DAMO systems remain unclear. Here, we revealed that Fe(III) in the influent did not affect nitrate removal rates but could induce continuous ammonium production and emission in the membrane granular sludge reactor (MGSR), accounting for about 13.7 % of nitrate removed. Excess methane and no residual nitrate were necessary conditions for the Fe(III)-induced ammonium production. DAMO archaea as the microorganism responsible for ammonium production always dominated the microbial community, while the relative abundance of DAMO bacteria decreased and anaerobic ammonium oxidizing (anammox) bacteria began to increase during the long-term operation, resulting in versatile nitrogen removal. Technical analyses showed that the ammonium production could cause an increase of 41.7 % in methane consumption of DAMO unit for treating ammonium-containing influents, thereby reducing the techno-economics. Therefore, special attention should be paid to the possible Fe(III)-induced ammonium generation in DAMO-centric technologies and avoiding excess methane may be a practical strategy to prevent it from happening.
反硝化厌氧甲烷氧化（DAMO）工艺利用厌氧消化产生的甲烷来去除氮，有助于废水处理的可持续运行。广泛存在于废水中的Fe(III)已被证明会影响DAMO古菌的氮代谢产物，但其对DAMO系统脱氮性能和微生物群落结构的长期影响仍不清楚。在此，我们发现进水的Fe(III)不影响硝酸盐去除率，但会在膜颗粒污泥反应器（MGSR）中诱导持续的铵产生和排放，约占去除硝酸盐的13.7%。过量的甲烷和无残留硝酸盐是Fe(III)诱导铵产生的必要条件。作为负责铵产生的微生物，DAMO古菌在微生物群落中始终占主导地位，而在长期运行过程中，DAMO细菌的相对丰度下降，厌氧氨氧化（anammox）细菌开始增加，从而实现了多种脱氮方式。技术分析表明，铵的产生会导致处理含铵进水的DAMO单元的甲烷消耗量增加41.7%，从而降低技术经济性。因此，应以DAMO为核心的技术中应特别关注可能由Fe(III)诱导产生的铵，避免过量甲烷可能是防止其发生的一种实用策略。
