Improved Performance of Microbial Fuel Cell by In Situ Methanogenesis Suppression While Treating Fish Market Wastewater

The fish market wastewater, which is rich in ammonium concentration, was investigated to explore its ability of in situ suppression of methanogenesis in the anodic chamber of microbial fuel cell (MFC) while treating it and to ensure non-reoccurrence of methanogenic consortia in the anodic chamber during its long-term operations. A lower specific methanogenic activity (0.097g chemical oxygen demand (COD)CH4/g volatile suspended solids (VSS). day) with a higher power density (3.81 ± 0.19 W/m3) was exhibited by the MFC operated with raw fish market wastewater as compared to the MFC fed with synthetic wastewater (0.219g CODCH4/g VSS. day and 1.75 ± 0.09 W/m3, respectively). The enhanced electrochemical activity of anodic biofilm of MFC fed with raw fish market wastewater than the MFC fed with synthetic wastewater further advocated the enhanced electrogenic activity and suppression of methanogenesis, because of the presence of higher ammonium content in the feed. This, in response, reduced the internal resistance (55 Ω), enhanced the coulombic efficiency (21.9 ± 0.3%) and normalized the energy recovery (0.27 kWh/m3) from the MFC fed with fish market wastewater than the MFC fed with synthetic wastewater (92 Ω, 15.7 ± 0.3% and 0.13 kWh/m3, respectively). Thus, while treating the fish market wastewater in the anodic chamber of MFC, any costly and repetitive treatment procedures for anodic microorganisms are not required for suppression of methanogens to ensure higher activity of electrogenic bacteria for higher electricity harvesting.