Synergistic effects of mechanical reciprocation, biogas scouring, and quorum quenching on membrane fouling mitigation in an Anaerobic Migrating Bed Reactor (AnMBR)

Membrane fouling remains a major challenge limiting the long-term operation of anaerobic membrane bioreactors (AnMBRs). This study investigated integrated anti-fouling strategies involving abrupt reciprocation, biogas scouring, and quorum-quenching (QQ) microorganisms to improve the hydraulic stability of the membrane in an anaerobic migrating bed reactor coupled with a submerged membrane system. The reactor startup performance was monitored over 17 weeks using chemical oxygen demand (COD) and biochemical oxygen demand (BOD) removal. Membrane fouling behavior was evaluated under different hydraulic fluxes (100, 200, and 400 LMH). The reactor achieved stable startup performance with COD and BOD reductions of 69.0% and 76.7%, respectively. Severe membrane fouling occurred at 400 LMH, where the permeate flow rate decreased by 73.5% within 48 h. Hermia model analysis indicated a transition from pore-blocking to cake-layer-dominated fouling during prolonged filtration. Moderate reciprocation frequencies (30 ~ 60 Hz) significantly improved membrane hydraulic performance. Compared with the control system, the QQ-assisted reactor maintained a higher permeate flow rate (53.2 mL/min) and a lower TMP accumulation (60.9 kPa) after 10 days of operation. Quorum quenching also reduced irreversible fouling contribution from 21.7% to 11.1%, indicating improved fouling reversibility. PCA and correlation analyses further confirmed that integrated anti-fouling strategies effectively modified membrane fouling pathways and improved long-term operational stability. Our findings showed that the combined application of abrupt reciprocation, biogas scouring, and quorum quenching exhibited strong synergistic effects in mitigating membrane fouling and supporting sustainable AnMBR operation.