Microbial fuel cell performance for aromatic hydrocarbon bioremediation and common effluent treatment plant wastewater treatment with bioelectricity generation through series-parallel connection

Microbial fuel cell (MFC) is an emerging technology which has been immensely investigated for wastewater treatment along with electricity generation. In the present study, the treatment efficiency of MFC was investigated for hydrocarbon containing wastewater by optimizing various parameters of MFC. Mediator-less MFC (1·2 l) was constructed, and its performance was compared with mediated MFC with Escherichia coli as a biocatalyst. MFC with electrode having biofilm proved to be better compared with MFC inoculated with suspended cells. Analysis of increasing surface area of electrode by increasing their numbers indicated increase in COD reduction from 55 to 75%. Catholyte volume was optimized to be 750 ml. Sodium benzoate (0·721 g l^-1 ) and actual common effluent treatment plant (CETP) wastewater as anolyte produced 0·8 and 0·6 V voltage and 89 and 50% COD reduction, respectively, when a novel consortium of four bacterial strains were used. Twenty MFC systems with the developed consortium when electrically connected in series-parallel connection were able to generate 2·3 V and 0·5 mA current. This is the first report demonstrating the application of CETP wastewater in the MFC system, which shows potential of the system towards degradation of complex organic components present in industrial wastewater.

Optimization of microbial fuel cell process using a novel consortium for aromatic hydrocarbon bioremediation and bioelectricity generation

Microbial Fuel Cell (MFC) is an innovative bio-electrochemical approach which converts biochemical energy inherent in wastewater into electrical energy, thus contributing to circular economy. Five electrogenic bacteria, Kocuria rosea (GTPAS76), two strains of Bacillus circulans (GTPO28 and GTPAS54), and two strains of Corynebacterium vitaeruminis (GTPO38 and GTPO42) were isolated from a common effluent treatment plant (CETP) and were used individually as well as in consortium form to run double chambered "H" type microbial fuel cell. Individually they could produce voltage in the range of 0.4-0.7 V in the MFC systems. Consortium developed using GTPO28, GTPO38, GTPAS54 and GTPAS76 were capable of producing voltage output of 0.8 V with 81.81 % and 64 % COD and BOD reduction, respectively. The EPS production capacity and electricity generation by the isolated bacteria correlated significantly (r = 0.72). Various parameters like, effect of preformed biofilm, length of salt bridge and its reuse, aeration, substrate concentration and external resistance were studied in detail. The study emphasizes on improving the commercialization aspect of MFC with repeated use of salt bridge and improving wastewater treatment potential after optimization of MFC system. Polarization curve and power density trends were studied in optimized MFC. A maximum power density and current density achieved were 18.15 mW/m² and 370.37 mA/m², respectively using 5 mM sodium benzoate. This study reports the use of sodium benzoate as a substrate along with reusing of the salt bridge in MFC study with promising results for BOD and COD reduction, proving it to be futuristic technology for bio-based circular ecosystem development.