Mixed microbial consortia combined with low-cost electrodes synergistically enhance the performance of bioelectrochemical systems

Abstract

Microbial Fuel Cells (MFCs) have gained significant attention as a sustainable technology for simultaneous wastewater treatment and bioelectricity generation via the metabolic activity of electroactive microorganisms. This study focused on the design and optimization of a laboratory-scale dual-chamber MFC to enhance its electrical performance. The system was constructed using graphite electrodes, a proton exchange membrane, and a mixed microbial consortium obtained from anaerobic sludge that was used as the biocatalyst in the anodic chamber. Key operational parameters, such as substrate concentration, pH, external resistance, and electrode spacing, were systematically varied to investigate their influence on voltage generation and power density. The optimized configuration demonstrated maximum power output at a substrate (acetate) concentration of 6 g/L and a neutral pH of 7. Under these conditions, the MFC achieved the optimized single cell delivered a maximum power density of 87.4 mW m⁻2 with the methylene blue electron mediator, whereas a stack of 12 cells connected in series generated a peak open-circuit voltage of approximately 12 V, with each individual cell contributing about 0.814–1.09 V, together confirming the effectiveness of the low-cost electrode materials and the microbial activity. The study also revealed that the external resistance and electrode spacing played crucial roles in minimizing the internal losses and enhancing the electron flow through the circuit. The selection of inexpensive yet conductive electrode materials contributed to the cost-effectiveness and scalability of the system. Furthermore, the MFC maintained a stable voltage generation across multiple operational cycles, highlighting its potential for long-term use. These findings underscore the importance of strategic design and optimization for improving MFC performance, making it a viable candidate for renewable energy generation in conjunction with wastewater management. This study contributes to the advancement of MFC technologies for real-world decentralized energy solutions.