This study would investigate the effect of nano-Fe₃O₄ particles on the performance of membrane bioreactor (MBR), including membrane fouling, membrane rejection and microbial community. It can effectively alleviate membrane fouling and improve the effluent quality in MBR by bio-effect rather than nanoparticle adsorption. The lowest membrane fouling resistance was achieved at R_4-MBR (sludge and membrane surface with nano-Fe₃O₄), which decreased by 46.08%. Meanwhile, R_3-MBR (sludge with nano-Fe₃O₄) had the lowest concentration of COD in effluent which was below 20 mg/L in the stable phase of MBR operation. After applying nano-Fe₃O₄, the content of extracellular polymeric substances (EPS) and soluble microbial products (SMP) were both reduced with a lower molecular weight. From the microbial community analysis, the abundance of Proteobacteria increased from 25.06 to 45.11% at the phylum level in R_3-MBR. It contributed to removing organic substances in MBRs. Moreover, the nano-Fe₃O₄ restricted Bacteroidetes growth, especially in R_4-MBR, leading to a more excellent performance of membrane flux. Besides, the applied nano-Fe₃O₄ promoted the abundance of Quorum Quenching (QQ) microorganism, and declined the percentage of Quorum Sensing (QS) bacteria. Then, a lower content of N-Acyl-_l-Homoserine Lactones (AHLs) in containing nano-Fe₃O₄ sludge. That was also prone to control membrane fouling. Overall, this study indicates the nano-Fe₃O₄ particle is appropriate for elevating MBR performance, such as membrane fouling and effluent quality, by bio-effect.

本研究将研究纳米 Fe ₃ O ₄颗粒对膜生物反应器 (MBR) 性能的影响，包括膜污染、膜截留和微生物群落。它可以通过生物效应而不是纳米颗粒吸附来有效减轻膜污染并改善MBR中的出水质量。R _4- MBR（含纳米Fe ₃ O _{4 的}污泥和膜表面）获得最低的膜污染阻力，降低了46.08%。同时，R _3- MBR（含纳米Fe ₃ O _{4 的}污泥）在MBR运行的稳定阶段出水的COD浓度最低，低于20 mg/L。应用纳米铁后₃ O ₄，细胞外聚合物（EPS）和可溶性微生物产物（SMP）的含量均降低，分子量降低。从微生物群落分析来看，R _3- MBR中Proteobacteria的丰度从门水平的 25.06% 增加到 45.11% 。它有助于去除 MBR 中的有机物质。此外，纳米Fe ₃ O ₄限制了拟杆菌的生长，尤其是在R _4- MBR 中，导致膜通量更优异。此外，应用纳米Fe ₃ O ₄提高了群体淬灭（QQ）微生物的丰度，并降低了群体感应（QS）细菌的百分比。然后，在含有纳米Fe ₃ O ₄污泥中的N-酰基_-1-高丝氨酸内酯(AHL)含量较低。这也易于控制膜污染。总体而言，该研究表明纳米 Fe ₃ O ₄颗粒适合通过生物效应提高 MBR 性能，例如膜污染和出水质量。