Use of Anaerobic Sludge Microbial Consortia in a Microbial Fuel Cell Biosensor for Biochemical Oxygen Demand Measurement

Abstract Effective management of wastewater treatment plants often require real-time measurements of Biochemical Oxygen Demand (BOD). The conventional methods for determining Biochemical Oxygen Demand (BOD) are often time-consuming, labor-intensive and prone to inaccuracies. Microbial Fuel Cells (MFCs) have emerged as a viable alternative technology for BOD measurement, offering real-time monitoring capability. This study developed a cost-effective dual-chamber MFC with graphite felt electrodes and a CMI-7000 membrane, inoculated with a microbial consortia grown from anaerobic sludge at optimal conditions (35 °C, pH 7, 1000 Ω external resistance). After one month of biofilm formation, the MFC produced 600 mV. Voltage outputs were measured at six BOD5 concentrations (36 to 583 mg/L) in synthetic wastewater, showing a strong linear correlation between BOD5 concentrations and voltage outputs. The MFC was also tested with five domestic wastewater samples, and BOD5 values derived from the voltage-BOD correlation were within 2.5% to 11% of conventional laboratory results. These findings confirm the potential of MFC-based biosensors as an efficient and accurate tool for real-time wastewater monitoring.