Mitigating membrane fouling based on in-situ •OH generation in a novel electro-Fenton membrane bioreactor

A novel electro-Fenton membrane bioreactor was constructed to investigate the effect of electro-Fenton on mitigating membrane fouling. Herein, porous carbon (PC), carbon nanotubes (CNTs) and Fe2+ were spun into hollow fiber membranes (Fe-PC-CHFM), then served as cathode and filtration core simultaneously. The H2O2 can be in-situ produced by O2 reduction with electro-assistance, and further induce hydroxyl radicals (•OH) generation with loaded Fe2+ on the surface of Fe-PC-CHFM. In addition, Fe3+/Fe2+ cycle can be realized effectively by the electro-assistance, avoiding ferrous iron addition. During over 100-day operation, the electro-Fenton membrane bioreactor achieved 93% of COD and 88% of NH4+-N removal at a HRT of 8 h. At the end of operation, the membranes in electro-Fenton membrane bioreactor still exhibited obviously mesh-like structure similarly to initial level. Importantly, merely 15min with an operation voltage of -0.8 V was sufficient to completely recover permeate flux of the fouled Fe-PC-CHFM. The energy consumption used for membrane fouling control was barely 8.64×10-5 kW·h/m3. Therefore, this novel energy-saved electro-Fenton membrane bioreactor process could provide an envisaging prospective and promising method for practice wastewater membrane treatment.