Performance of a Hybrid Biocathode Microbial Fuel Cell for Wastewater Treatment and Electricity Generation

An up-flow single-chamber biocathode microbial fuel cell was applied to investigate the effect of cathode substrate material on power generation and wastewater treatment. Granular activated carbon (2-4 mm) was used as the anode substrate material, and granular graphite (2-4, 4-8, 8-12 mm) was used as the cathode substrate material. Glass fiber was used as separators between electrodes. When the granular graphite (4-8 mm) was used as the cathode substrate, the electricity generated was up to a voltage of 534 mV and a power density of 631.6 mW/m³. The maximum coulombic efficiency was 3.82%, and the external resistance was 1000 Ω. The high cathode hydrogen ion concentration could result in high cathode potential that was conducive to electricity production response in the cathode compartment. The removal efficiency of COD_Cr was on average 80% of MFCs with different cathode substrate material. Besides, the maximum removal efficiencies of the total nitrogen, ammonia nitrogen and total phosphorus were 79%, 93% and 34%, respectively. The results indicated that the material and particle size of cathode substrate had a great effect on electricity generation, but had little effect on the wastewater treatment.