The application of partial nitritation and anammox to remove nitrogen from mainstream wastewater is of great interest because of the potential to reduce energy cost and carbon dosage. However, this process confronts a dilemma of relatively high effluent nitrogen concentration (>10 mg N/L), owning to the unwanted prevalence of nitrite-oxidizing bacteria (NOB) and the intrinsic nitrate production by anammox bacteria. Here, a novel technology, named the one-stage PNAM, that integrates Partial Nitritation, Anammox and Methane-dependent nitrite/nitrate reduction reactions, was developed in a single membrane biofilm reactor (MBfR). With feeding of synthetic mainstream wastewater containing ∼50 mg NH₄⁺-N/L at a hydraulic retention time of 12 h, more than 95% nitrogen was removed in the established one-stage PNAM process at a practically useful rate of 0.1 kg N/m³/d. Microbial community characterization and in-situ batch tests revealed a sophisticated microbial structure consisting of ammonia-oxidizing bacteria (AOB), anammox bacteria, nitrite/nitrate-dependent anaerobic methane oxidation (n-DAMO) bacteria and archaea, and a small fraction of NOB and aerobic methanotrophs. The role of methane in removing nitrate was confirmed by switching on/off the methane supply, which relaxed the requirement for NOB suppression. In addition, the established system was relatively robust against temperature variations, evidenced by a total nitrogen removal efficiency above 80% at temperature as low as 14 ℃. The results provide a promising alternative for efficient nitrogen removal from domestic wastewater using methane as the sole carbon source.

由于具有降低能源成本和碳用量的潜力，部分亚硝化和厌氧氨氧化从主流废水中去除氮的应用引起了极大的兴趣。然而，该过程面临着出水氮浓度相对较高（>10 mg N/L）的困境，这是由于亚硝酸盐氧化细菌 (NOB) 的不受欢迎以及厌氧氨氧化细菌产生的固有硝酸盐。在此，一种新型的技术，称为一阶段PNAM，集成P artial Ñ itritation，甲nammox和中号乙烷依赖性还原亚硝酸盐/硝酸盐反应，在一个单一的膜生物膜反应器（MBfR中）的开发。加入含有约 50 mg NH ₄ ⁺的合成主流废水-N/L 在水力停留时间为 12 小时时，在已建立的一级 PNAM 工艺中以 0.1 kg N/m ³ /d的实用速率去除了超过 95% 的氮。微生物群落表征和原位批量测试揭示了一种复杂的微生物结构，包括氨氧化细菌 (AOB)、厌氧氨氧化细菌、亚硝酸盐/硝酸盐依赖性厌氧甲烷氧化 (n-DAMO) 细菌和古细菌，以及一小部分 NOB 和好氧甲烷氧化菌。甲烷在去除硝酸盐方面的作用通过打开/关闭甲烷供应得到证实，这放宽了抑制 NOB 的要求。此外，所建立的系统对温度变化相对稳健，在低至 14 ℃ 的温度下总脱氮效率超过 80% 就证明了这一点。该结果为使用甲烷作为唯一碳源从生活废水中有效去除氮提供了一种有前途的替代方案。