Removal of organic matters and nitrogenous pollutants simultaneously from two different wastewaters using biocathode microbial fuel cell

Abstract

In this study, a dual chamber MFC was constructed for simultaneous removal of organic matter and nitrogenous pollutants and bioelectricity generation from synthetic and complex industrial wastewaters and it was operated in batch and continuous mode. When the cell potential was stable after 16 days of batch mode operation, the MFC was converted to continuous mode (from batch mode) and operated for 125 days with different organic loading rates (OLR) and ammonia loading rates (ALR) and fixed hydraulic retention time (HRT) of 40 h. The OLR of 1.49 kg COD m−3 d−1 and ALR of 0.58 kg NH3− m−3 d−1, for anodic and cathodic chambers, respectively, gave the best results. The highest value of cell potential on these OLRs was 310 mV with current density of 85.11 mA m−2, power density of 26.38 mW m−2 and volumetric power density of 192.20 mW m−3. During this period, COD reduction was 78–83% in the anodic chamber and the ammonia reduction was 36–38%. After stable operation with synthetic wastewater one case study was performed with complex industrial wastewater. Continuous mode operation was performed at two different OLR and HRT with a constant ALR. A stable power density and volumetric power density of 23.56 mW m−2 and 112.50 mW m−3, respectively were achieved after 24 days of continuous operation at an OLR of 0.35 kg COD/m3 day with an ALR of 0.43 kg NH3− m−3 day−1 and corresponding HRT of 68 h. A maximum of 89% COD removal and 40% removal of ammonia was obtained after 50 days. A stable voltage of 300 mV was obtained across 1000 Ω resistance. These findings suggest that BMFC can be used for the treatment of industrial wastewater, with carbon removal in anodic chamber and electricity generation.