State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China; Australian Centre for Water and Environmental Biotechnology, The University of Queensland, St Lucia, QLD 4072, Australia; National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Engineering Research Center of Beijing, Beijing University of Technology, Beijing 100124, China.
State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China.
Water Res. 2024 Jun 15;257:121701. doi: 10.1016/j.watres.2024.121701. Epub 2024 Apr 30.
Nitrate or nitrite-dependent anaerobic methane oxidation (n-DAMO) is a microbial process that links carbon and nitrogen cycles as a methane sink in many natural environments. This study demonstrates, for the first time, that the nitrite-dependent anaerobic methane oxidation (nitrite-DAMO) process can be stimulated in sewer systems under continuous nitrate dosing for sulfide control. In a laboratory sewer system, continuous nitrate dosing not only achieved complete sulfide removal, but also significantly decreased dissolved methane concentration by ∼50 %. Independent batch tests confirmed the coupling of methane oxidation with nitrate and nitrite reduction, revealing similar methane oxidation rates of 3.68 ± 0.5 mg CH L h (with nitrate as electron acceptor) and 3.57 ± 0.4 mg CH L h (with nitrite as electron acceptor). Comprehensive microbial analysis unveiled the presence of a subgroup of the NC10 phylum, namely Candidatus Methylomirabilis (n-DAMO bacteria that couples nitrite reduction with methane oxidation), growing in sewer biofilms and surface sediments with relative abundances of 1.9 % and 1.6 %, respectively. In contrast, n-DAMO archaea that couple methane oxidation solely to nitrate reduction were not detected. Together these results indicated the successful enrichment of n-DAMO bacteria in sewerage systems, contributing to approx. 64 % of nitrite reduction and around 50 % of dissolved methane removal through the nitrite-DAMO process, as estimated by mass balance analysis. The occurrence of the nitrite-DAMO process in sewer systems opens a new path to sewer methane emissions.
硝酸盐或亚硝酸盐依赖型厌氧甲烷氧化（n-DAMO）是一种微生物过程，它作为许多自然环境中的甲烷汇，将碳氮循环联系起来。本研究首次表明，在连续硝酸盐投加以控制硫化物的情况下，污水系统中可以刺激亚硝酸盐依赖型厌氧甲烷氧化（nitrite-DAMO）过程。在实验室污水系统中，连续硝酸盐投加不仅实现了完全去除硫化物，而且还显著降低了约 50%的溶解甲烷浓度。独立的批量测试证实了甲烷氧化与硝酸盐和亚硝酸盐还原的耦合，揭示了相似的甲烷氧化速率为 3.68 ± 0.5 mg CH L h（以硝酸盐为电子受体）和 3.57 ± 0.4 mg CH L h（以亚硝酸盐为电子受体）。综合微生物分析揭示了 NC10 门的一个亚群的存在，即 Candidatus Methylomirabilis（将亚硝酸盐还原与甲烷氧化偶联的 n-DAMO 细菌），在污水生物膜和表层沉积物中分别以相对丰度 1.9%和 1.6%生长。相比之下，没有检测到仅将甲烷氧化偶联到硝酸盐还原的 n-DAMO 古菌。这些结果共同表明，n-DAMO 细菌在污水系统中的成功富集，通过 nitrite-DAMO 过程贡献了约 64%的亚硝酸盐还原和约 50%的溶解甲烷去除，这是通过质量平衡分析估计的。硝态氮依赖型厌氧甲烷氧化过程在污水系统中的发生为污水甲烷排放开辟了新途径。
