Performance of mediator-less and membrane-less microbial fuel cell (ML–MFC) was evaluated to treat synthetic wastewater and actual sewage. The ML–MFC gave COD and BOD removal efficiencies of 88% and 87%, respectively, and TKN removal was around 45–50%. Biomass granulation was observed in the anode compartment of ML–MFC. Effect of distance between the electrodes and total surface area of anode on electricity production was evaluated under variable external resistance. Maximum power density of 10.9 and 10.13 mW/m2 was observed at lower spacing between the electrodes (20 cm) and for lesser surface area of the anode, respectively. With variation in the carbon source in the feed, variation in power production was observed.