[Performance of a single chamber microbial fuel cell utilizing Dioscorea zingiberensis C. H. Wright wastewater]

The possibility of electricity generation in a single chamber microbial fuel cell fed with Dioscorea zingiberensis C. H. Wright wastewater was demonstrated, and the effects of COD and SO4(2-) concentration on MFC performance were investigated. Under the same conductivity and COD concentration, the power density generated from wastewater equaled to 80.3% of that from glucose. At low COD concentration, the electricity generation increased with increasing COD loading rates, and the maximum power density was 322 mW/m2; while the COD concentration was enhanced over 2766 mg/L, the stable times for electricity generation was reduced and the MFC could not recover to previous performance as refueling. That indicates high COD loading rates would inhibit microbial activity. The COD removal rates varied from 68.2% to 84.8%, and it decreased when COD concentration climbed up. The power density was enhanced with SO4(2-) concentration increasing up to 7716 mg/L (Conductivity > 8.19 mS/cm) after which no further improvements in power density were observed. The maximum power density of the wastewater containing SO4(2-) was lower by 14.5% on average than that of the wastewater which removed SO4(2-). And its coulombic efficiencies declined substantially as SO4(2-) concentration increasing, which imply that the SO4(2-) is deoxidized as the electron acceptor, which takes the MFC efficiency down.