Enhanced antifouling behavior and phosphorus removal in a gravity-driven electrochemical dynamic membrane bioreactor (EDMBR) process: Performance and mechanisms

Gravity-driven dynamic membrane bioreactor (DMBR) process has emerged as a promising wastewater treatment technology. However, long dynamic membrane (DM) formation time, membrane fouling and low phosphorus removal have limited its widespread application. A novel gravity-driven electro-DMBR (EDMBR) using stainless-steel meshes as the anodic membrane and graphite plates as the cathodes was developed for domestic wastewater treatment, with process performance, DM properties and energy consumption compared with a control DMBR without external voltage applied. Electrostatic adsorption between negatively charged foulants and positively charged anodic membrane shortened DM formation time to less than 4 min. Afterwards, electro-oxidation effect and biodegradation effect resulted from the enrichment of electroactive microorganisms (such as Pseudomonas, Acinetobacter, Exiguobacterium) ensured continuous degradation of attached foulants and maintained a thin and well-structured DM layer, showing higher stable flux and reduced cleaning frequency at the voltage of 1.2 V and 1.6 V compared to the control DMBR. The electro-coagulation (EC) effect originated from iron releasing modified the sludge properties and enhanced phosphorus removal (74 %-87 %). Moreover, the EDMBR with higher permeability and treatment capacity resulted in lower energy consumption (0.41-0.44 kWh/m(3)) compared to the DMBR (0.50 kWh/m(3)). The results provide new insights into sustainable operation of the EDMBR process towards lower energy demand and less maintenance requirement.