Eutrophication and global warming are two main urgent environmental problems around the world. Nitrate-dependent Anaerobic Methane Oxidation (NdAMO) is a bioprocess coupling nitrate reduction with anaerobic methane oxidation, which could mitigate of these two environmental issues simultaneously. In this study, a newly granular active carbon-NdAMO-membrane bioreactor (GAC-NdAMO-MBR) system was established to evaluate its nitrogen removal efficiency, membrane fouling property and the probable strengthening mechanism was also uncovered. Results indicated that the nitrate removal rate in GAC-NdAMO-MBR reached 31.85 ± 3.19 mgN·L⁻¹·d⁻¹ while it was only 10.35 ± 2.02 mgN·L⁻¹·d⁻¹ in NdAMO-MBR system (lack of GAC), which was multiplied three-fold. The membrane flux decay rate of GAC- NdAMO -MBR was 0.15 L/m²·h·d while it was 0.49 L/m²·h·d without GAC, and the addition of GAC could extend membrane fouling time for 2.5 times. Notablely, the relative abundance of NdAMO bacteria sharply increased from 27.15% to 56.91% after GAC addition while the NdAMO archaea showed similar variation trend. The physicochemical property of GAC mainly contributed the strengthening effect. The porous structure of GAC absorbed methane and adhered by microorganism, which enhance microorganism amount and metabolic activity. The mechanical strength of GAC scoured membrane surface to mitigate external fouling and pores absorbed EPS to reduce internal fouling. The combined effects could improve NdAMO microorganism growth and metabolism activity and finally improved nitrogen removal performance and controlled membrane fouling. These findings could deep the knowledge of NdAMO process and help extend its application potential in environment science and engineering.

富营养化和全球变暖是世界上两个主要的紧急环境问题。硝酸盐依赖性厌氧甲烷氧化（NdAMO）是将硝酸盐还原与厌氧甲烷氧化结合在一起的生物过程，可以同时缓解这两个环境问题。本研究建立了一种新型的颗粒状活性炭-NdAMO-膜生物反应器（GAC-NdAMO-MBR）系统，以评价其脱氮效率，膜污染特性以及可能的强化机理。结果表明，GAC-NdAMO-MBR的硝酸盐去除率达到31.85±3.19 mgN·L ^-1 ·d ^-1，而仅为10.35±2.02 mgN·L ^-1 ·d ^-1在NdAMO-MBR系统（缺少GAC）中，它是原来的三倍。GAC-NdAMO -MBR的膜通量衰减率为0.15 L / m ² ·h·d，而为0.49 L / m ²·h·d不加GAC，加入GAC可将膜污染时间延长2.5倍。值得注意的是，添加GAC后，NdAMO细菌的相对丰度从27.15％急剧增加到56.91％，而NdAMO古细菌显示出相似的变化趋势。GAC的理化性质主要是增强作用。GAC的多孔结构吸收了甲烷并被微生物粘附，从而增加了微生物的数量和代谢活性。GAC的机械强度可冲刷膜表面，以减轻外部结垢，而毛孔吸收的EPS可减少内部结垢。这些综合作用可以改善NdAMO微生物的生长和代谢活性，并最终改善脱氮性能和控制膜污染。