High speed municipal sewage treatment in microbial fuel cell integrated with anaerobic membrane filtration system

A cylindrical two chambered microbial fuel cell (MFC) integrated with an anaerobic membrane filter was designed and constructed to evaluate bioelectricity generation and removal efficiency of organic substrate (glucose or domestic wastewater) depending on organic loading rates (OLRs). The MFC was continuously operated with OLRs 3.75, 5.0, 6.25, and 9.38 kg chemical oxygen demand (COD)/(m³·d) using glucose as a substrate, and the cathode chamber was maintained at 5–7 mg/L of dissolved oxygen. The optimal OLR was found to be 6.25 kgCOD/(m³·d) (hydraulic retention time (HRT) 1.9 h), and the corresponding voltage and power density averaged during the operation were 0.15 V and 13.6 mW/m³. With OLR 6.25 kgCOD/(m³·d) using domestic wastewater as a substrate, the voltage and power reached to 0.13 V and 91 mW/m³ in the air cathode system. Even though a relatively short HRT of 1.9 h was applied, stable effluent could be obtained by the membrane filtration system and the following air purging. In addition, the short HRT would provide economic benefit in terms of reduction of construction and operating costs compared with a conventional aerobic treatment process.