Performance of microbial fuel cells in treating petroleum refinery wastewater

A high level of chemical energy is contained in petroleum refinery wastewater (PRW). In this study, the per-formance of microbial fuel cell (MFC) treating PRW is investigated in various MFC reactor configurations by studying the removal rate of chemical oxygen demand (COD) from wastewater and the generation of electricity. The effect of different hydraulic retention times (HRTs) with a selected external resistance and the effect of catholyte of different pHs were investigated in batch and continuous mode of operations using single chamber and dual chamber MFCs. The results of continuous modes of operation in dual-chamber MFC indicated that the efficiency of COD removal in treating PRW reached 84.40 %. The bioelectricity generation in terms of voltage and current output of MFC was observed to be higher in continuous mode dual chamber operation with cathodic aeration. The highest obtained cell voltage of 762 mV and the highest volumetric power density of 328.26 mW/ m(3) were reached in continuously operated dual-chamber MFC at HRT of 16 h. The highest current density obtained was 79.2 mA/m(2). This study indicates that the performance of MFC treating PRW is promising and continuous mode can be employed for treating PRW with simultaneous generation of electricity.