Performance evaluation of Fe₃O₄@ACF-supported bio-electro Fenton system for simultaneous sewage treatment and methyl orange degradation

The development of an integrated wastewater treatment system is a challenging endeavor in modernized cities. Herein, a four-electrode-based electro Fenton coupled bio-electrochemical system (EF-BES) was developed to take advantages of both bio-electrochemical system (BES) and electro Fenton (EF) process in wastewater treatment. For it, a polarizable Fe₃O₄@ACF cathode was synthesized by the wet-phase activation to enhance the degradation power of the electrochemical advanced oxidation process, i.e., EF system. The iron particles in Fe₃O₄@ACF were used as a bridge for electron transfer to polarize the cathode. After 25-days, polarization of activated sludge inoculated BES generated an approximate of 275.23 ± 9.35 mW cm⁻² of power density. The power was utilized as an energy source with which the EF-BES could degrade Methyl orange (MO) containing wastewater. At the optimum operating condition, the MO degradation efficiency 82.5 ± 4.27% could be achieved over 40 h. In addition to MO degradation, organics and NH₄⁺ in sewage could be removed simultaneously; the observed TOC, COD and NH₄⁺-N removal efficiencies were 67.4 ± 3.6%, 71.2 ± 3.8% and 69.3 ± 3.7%, respectively. Overall, the coupled EF-BES system is a promising treatment technology for MO-containing wastewater.