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[Display omitted] • Applying electric field suppressed membrane fouling rate of AnMBR. • Applying electric field decreased the deposition of organic foulants on membrane. • Contribution of electrophoresis to membrane fouling suppression was quantified. • Applying electric field improved mixed liquor filterability of AnMBR. • Mechanism of mixed liquor filterability improvement was analyzed. Anaerobic membrane bioreactor (AnMBR) is a promising technology for wastewater treatment. However, membrane fouling as an inevitable challenge restricts its application. Recently novel membrane fouling control technology by applying electric field in AnMBR showed its economics and effectiveness. Nevertheless, the mechanism of fouling suppression is still unclear, limiting the development of this technology. In this study, electro-AnMBR was constructed. Long-term running showed that applying electric field of 0.5 V suppressed the membrane fouling evolution rate by nearly 23% and reduced the organic foulants on membrane by nearly 10%. To clarify the mechanism of fouling suppression, the contribution of electrophoresis to membrane fouling suppression was quantified by theoretical calculation for the first time. Results showed that electrophoresis was approximately equivalent to backwash with a flux of 0.56 L/(m2·h). Besides, impact of electric field on mixed liquor filterability of AnMBR was first investigated by dead-end filtration. Results presented that electric field reduced the filtration resistance of mixed liquor by nearly 77%. Then mixed liquor properties analysis, electrochemical oxidation simulation tests and metagenomic analysis revealed that electric field might improve mixed liquor filterability by bioelectrochemical oxidation. Finally, novel mechanism of electric field suppressed membrane fouling was elucidated, including electrophoresis to drive off the foulants and mixed liquor filterability improvement. This study might contribute to better understanding for membrane fouling control by applying electric field in AnMBR, and was meaningful for technical development. [ABSTRACT FROM AUTHOR]

• ZVI showed its versatility for improving the performances of AnMBR. • Applying ZVI enhanced COD and TP removal, H 2 S removal. • Applying ZVI without electric field suppressed membrane fouling. • The occurrences of the iron ions in AnMBR were studied. • Iron ions releasing rate of ZVI is vital parameter for enhanced performances. Comprehensive insight into the long-term impact of applying zero valent iron (ZVI) in anaerobic membrane reactor (AnMBR) was conducted here. ZVI showed its versatility for enhancing the performances of AnMBR including COD and TP removal, H 2 S removal and membrane fouling suppression in this study, and the iron ions releasing rate of ZVI had great influence on the enhancing performances. Two iron ions releasing states were used including "with electric field" and "without electric field". Applying electric field could boost iron ions releasing rate by 12 times here. COD removal rate increased by 3% via coagulation effect with and without electric field. H 2 S in biogas was decreased from >500 ppm to <60 ppm via the formation of FeS precipitation with and without electric field. Applying ZVI with electric field increased the removal rate of TP by 50% via the formation of Fe 3 (PO 4) 2 , but applying ZVI without electric field did not change the TP removal due to the insufficient iron ions. Utilizing ZVI without electric field suppressed the membrane fouling rate by 20% via the improvement of mixed liquor filterability, however utilizing ZVI with electric field accelerated the membrane fouling rate by 17 times due to the formation of dense Fe-enriched fouling layer with server inorganic and organic fouling. This study provided a novel approach to improve the performances of AnMBR by utilizing versatile ZVI. Meanwhile, this study enclosed that the iron ions releasing rate of ZVI is vital technical parameter for its application. [ABSTRACT FROM AUTHOR]