Reductive dechlorination and mineralization of pentachlorophenol in biocathode microbial fuel cells

Simultaneous anaerobic and aerobic degradation pathways in two-chamber, tubular microbial fuel cells (MFCs) facilitated pentachlorophenol (PCP) mineralization by a mediator-less biocathode. PCP was degraded at a rate of 0.263 ± 0.05 mg/L-h (51.5 mg/g VSS-h) along with power generation of 2.5 ± 0.03 W/m3. Operating the biocathode MFC at 50 °C improved the PCP degradation rate to 0.523 ± 0.08 mg/L-h (103 mg/g VSS-h) and power production to 5.2 ± 0.03 W/m3. A pH of 6.0 increased the PCP degradation rate to 0.365 ± 0.02 mg/L-h (71.5 mg/g VSS-h), but reduced power. While mediators were not needed, adding anthraquinone-2,6-disulfonate increased power and PCP degradation rates. Dominant bacteria most similar to the anaerobic Desulfobacterium aniline, Actinomycetes and Streptacidiphilus, and aerobic Rhodococcus erythropolis, Amycolatopsis and Gordonia were found on the biocathode. These results demonstrate efficient degradation of PCP in biocathode MFCs and the effects of temperature, pH and mediators.