In the present study, the effects of electrode surface area, proton exchange membrane area, and volume of the anodic chamber were investigated on the performance of five different dual chamber microbial fuel cells (MFC) using synthetic wastewater toward wastewater treatment coupled electricity generation. In the batch mode, the five different MFC's were operated with the anodic chamber volumes of 93-890 mL, 17.33-56.77 cm electrode surface area, obtained volumetric power densities of 137.72-58.13 mW/m, and unit area power densities ranging from 27.04 to 11.94 mW/m. Fed-batch studies were done with the MFC having 740 mL anodic chamber volume at different wastewater COD concentrations. The power density per unit area increased from 22.93 mW/m to 36.25 cm when the distance between electrodes was reduced from 10 to 6 cm. A maximum volumetric power density of 135.21 mW/m has been attained with a 6 cm electrode distance with the accomplished COD reduction of 93.21%. The presence of biofilm on the anode has been visualized through the SEM images. The higher COD concentration of wastewater and the fed-batch operation resulted in increased power output and wastewater treatment efficiency.