The Effects of Salinity, pH and Temperature on the Performance of a Microbial Fuel Cell

Abstract

In order to develop microbial fuel cells (MFCs) as a wastewater treatment technology, it is necessary to investigate the performance of these systems under various operating conditions. This study investigated the effect of salinity, pH and temperature on the performance of a dual chamber MFC. All experiments were conducted in batch mode using synthetic wastewater as a medium (based on approximately 0.55 gCOD/L glucose). The performance was evaluated in terms of chemical oxygen demand (COD) removal efficiency, coulombic efficiency (CE) and power production. Good electrochemical performance (Pmax 66 mW/m2) and COD removal efficiency (70 %) were maintained up to a salinity of 4.1 g/L, but Pmax decreased by 92 % and COD removal by 25.3 %, as the salinity was raised to 6.7 g/L. The optimum CE (13 %) was achieved at 4.1 g/L. Maximum power density was improved by 37 % (Pmax 50.6 mW/m2) as the pH of the anolyte was increased from 6 to 9, while the optimum CE (15 %) was achieved at pH 7. Moreover, maximum power density and CE were both improved by 64 % (Pmax 59 mW/m2) and 211 % (CE 14 %), when the operating temperature was raised from 24 to 35 °C. The COD removal efficiency remained approximately constant (75–80 %) for all pH and temperature changes. These results indicate the great influence of salinity, pH and temperature on MFC performance in terms of power generation and wastewater treatment.