A horizontal plug flow and stackable pilot microbial fuel cell for municipal wastewater treatment

An application-oriented stackable horizontal MFC (SHMFC) was designed and proved to be capable for sewage treatment and simultaneously energy recovery. The system consisted of multiple stackable 250 L modules, which is the largest single MFC module by far. Domestic wastewater was fed into SHMFC in horizontal advection. During the stable operation period, a maximum current 0.435 ± 0.010 A in each module was observed under the external resistance of 1 Ω and the maximum power density was 116 mW. The effluent COD was 70 ± 17 mg L−1 with a removal rate of 79 ± 7% and the effluent TN was 13 ± 3 mg L−1 with a removal rate of 71 ± 8%. From the comparison between SHMFC module (250 L) and 4-cm cubic MFC (28 mL), the internal resistance distribution changes and the contact resistance becomes assignable and even limiting factor in the enlargement.