Simultaneous removal of organics and bioenergy production by microbial fuel cell: modeling approach

Abstract

Abstract In this study, membrane less double chambered microbial fuel cell has been used for the simultaneous electricity generation and organics removal from glucose and glutamic acid (mole ratio 1:1) based synthetic solution in the presence of municipal wastewater activated sludge-based microbes using graphite as an electrode. A central composite design technique has been employed to optimize the experimental conditions using design expert software for modeling input–output model as surface function of various input parameters like initial COD, anodic pH, and run time for voltage and current density generation. The predicted model suggests that maximum voltage and current density generation of ∼14.8 mV and ∼41.11 μA/m2, respectively are obtained at COD: 1500 mg/L, pH: 7, run time: 7 days. Further, methylene blue is used as mediator for voltage and current density production at optimum condition. Experimental result depicts the substantial role of mediator concentration and showing maximum current and voltage production, approximately 10 times higher than that without meditator under similar conditions. In addition to bioenergy production, values of BOD and COD in the wastewater simulant are found to be reduced after each run which exists below the permissible limits. The developed model equations give better prediction on the voltage and current density generation which lies within the error limits of −12 to +12% and −2 to 14%, respectively to their corresponding experimental values. Overall, the process can generate simultaneously bioenergy along with wastewater treatment and the empirical model gives better prediction with experimental values.