Low electric field-assisted anaerobic ceramic membrane reactor for high-concentration organic wastewater treatment: Performance enhancement and membrane fouling mitigation

Severe membrane fouling and limited energy recovery have restricted the application of anaerobic ceramic membrane reactor (AnCMBR) in treating high-concentration organic wastewater. In the present study, a low electric field at the voltage of 0.8 V was applied to establish E-AnCMBR to enhance pollutants removal, improve energy recovery and alleviate membrane fouling. The highest removal rate of COD, NH₄⁺ -N and phosphorus was 98.5 ± 0.5 %, 52.4 ± 0.9 % and 63.0 ± 0.9 % at the organic loading rate (OLR) of 3.80 kgCOD/(m³·d), respectively, under which the methane yields reached the maximum value of 0.51 ± 0.02 L/gCOD. The mixtures of the E-AnCMBR exhibited low extracellular polymeric substance concentration and large floc size due to the combined effect of electrocoagulation and electrical stimulation, which significantly reducing membrane fouling tendency. The presence of Fe(Ⅱ)/Fe(Ⅲ) enhanced the synergy among potential electroactive bacteria (e.g., Desulfobacterota) and methanogens in the E-AnCMBR. Along with electrochemical and physical effect, the long-term performance stability, improved methanogenesis and membrane fouling mitigation were achieved. This study provides an energy-efficient approach for sustainable high-concentration organic wastewater management, and offers clearer insights into the mechanisms underlying synergistic enhancements in pollutant removal, methanogenesis, and membrane fouling control within the E-AnCMBR.