An anoxic/oxic membrane bioreactor (MBR) and three side-stream reactor (SSR) coupled membrane bioreactors were operated in parallel to investigate effects of dissolved oxygen (DO) level in SSR on sludge reduction and microbial community structure of SSR-MBRs. The four MBRs were equally efficient in COD and ammonium nitrogen removal. The anaerobic and micro-aerobic SSR favored nitrogen removal through denitrification, simultaneous nitrification and denitrification and autochthonous substrate release as carbon source. The micro-aerobic SSR achieved greatly higher sludge reduction efficiency (61.1%) than anaerobic (37.3%) and aerobic SSR (7.9%). Micro-aerobic SSR obtained the highest endogenous decay constant (0.035 d⁻¹) compared to anaerobic (0.023 d⁻¹) and aerobic SSR (0.015 d⁻¹). High-throughput sequencing results revealed that anaerobic SSR enriched hydrolytic and fermentative bacteria, aerobic environment favored the growth of slow-growing bacteria, and micro-aerobic SSR stimulated biological activities of both anaerobic and aerobic bacteria.

并联运行一个缺氧/氧化膜生物反应器（MBR）和三个侧流反应器（SSR）耦合的膜生物反应器，以研究SSR中的溶解氧（DO）水平对SSR-MBR的污泥减少和微生物群落结构的影响。四个MBR在去除COD和去除铵态氮方面同样有效。厌氧和微好氧的SSR有利于通过反硝化，同时硝化和反硝化以及自生底物的释放作为碳源来脱氮。与好氧（37.3％）和好氧SSR（7.9％）相比，微好氧SSR的污泥减少效率（61.1％）大大提高。与好氧（0.023 d ^-1）和好氧SSR（0.015 d ）相比，微好氧SSR的内生衰减常数最高（0.035 d ^-1）。^-1）。高通量测序结果表明，厌氧SSR丰富了水解和发酵细菌，好氧环境有利于缓慢生长的细菌的生长，微需氧SSR刺激了厌氧和需氧细菌的生物活性。