Simultaneous carbon and nitrogen removal using loop configuration microbial fuel cell (MFC) with relatively large size of 5 L was investigated in this study. Four MFC reactors were constructed with a loop configuration to eliminate the pH gradient, and the reactor performance was examined with different separators and cathode materials. The performance of the reactors in terms of electricity generation and contaminant removal rate was examined. Results showed that a maximum power density of 1415.6 mW/m(3) (The empty bed volume of anode chamber) was obtained at a current density of 3258.5 mA/m(3) with cation exchange membrane as separator and graphite felt (Pt coated) as cathode using the piggery wastewater as feed, and the organic removal rate obtained was approximately 0.523 kg COD/m(3)/d (total anode chamber) with nitrogen removal rate of 0.194 kg N/m(3)/d (total cathode chamber). (C) 2013 Elsevier Ltd. All rights reserved.