The parameters affecting steady state power generation for a lab-scale up-flow microbial fuel cell (UMFC) were studied. Single batch of domestic wastewater substrate was initially fed to the UMFC to determine the time span of maximum anaerobic bacterial activity by monitoring their lag, growth and death phases. This was performed indirectly by recording the variations in volumetric electric power with time. The UMFC was then operated using the batches of substrate, fed sequentially from anaerobic basins when the previously estimated time span showed the maximum activity of bacteria in the basin. At the maximum bacterial activity, the UMFC could continuously generate constant volumetric power of approximately 5.31 +/- 0.12 W m(-3). The effects of organic loading rate, flow rate and pH of the domestic wastewater on the voltage and volumetric electric current were also investigated. The results showed that increasing the organic loading rate and flow rate at neutral pH enhanced the voltage. A higher power could be generated using the UMFC for domestic wastewater treatment, as compared to the other works. (c) 2012 Elsevier Ltd. All rights reserved.