Simultaneous bioenergy production and dairy wastewater treatment by microbial fuel cell using Taguchi method: performance & optimization study

Abstract

Abstract Microbial fuel cell (MFC) employs microbial communities as biocatalysts to convert chemical energy from organic substrates to electrical energy. The investigation of MFC incorporated with anaerobic mixed cultures and sulfonated polystyrene (SPS) membrane is of interest for this research due to its competency in generating renewable biological energy and wastewater treatment. Methylene blue was an effective redox mediator in this study. The reactor optimization was performed via the Design of Experiments (DOE) approach using Minitab software. The performance of the batch reactor was optimal with the operating conditions of temperature 30 °C, pH 7, and mediator concentration 250 μM. The contour plots and ANOVA specified that mediator concentration was the most influential parameter that affects MFC performance. MFC fed with 250 μM methylene blue concentration generated a maximum voltage of 0.33 V, current (density) of 4.08 A/m2, power (density) of 1.34 W/m2. The COD removal was 82.4 % at the end of the batch cycle of seven days. The data obtained from the experiments showed that small amounts of a mediator (250 μM) in wastewater elevate the bio-electricity output of the MFC reactor by 1.22 folds.