Cost-effective activated carbon (AC) material was investigated for the development of gas-diffusion cathode employed in membraneless single chamber microbial fuel cells (SCMFCs) treating different feeding solutions. The electrocatalytic activity of AC cathodes was monitored in synthetic wastewater containing phosphate buffer saline solution and sodium acetate (PBS and NaOAc) and compared with several types of wastewaters (e.g. fresh urine (FU), hydrolysed urine (HU), wastewater and sodium acetate (WW + NaOAc) and raw wastewater (WW)). Solution conductivity and pH significantly affected the cathode and the SCMFCs performance. Synthetic wastewater (PBS) outperformed real wastewater in terms of cathode current and SCMFC power output. The results showed that the SCMFCs fed with urine generated 3 times higher power densities than those with raw WW and 25% higher than those with WW + NaOAc, most likely due to the high amount of electrons generated from organic substances. Chemical analysis showed that nutrient concentrations remained the same in the SCMFCs fed with PBS, but decreased 40% in those fed with urine. High power generation associated with phosphorus removal underlines the possibility of using urine as a feedstock for MFCs in real wastewater treatment processes. Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.