Concurrent hydrogen (H-2) production and phosphorus (P) recovery were investigated in dual chamber microbial electrolysis cells (MECs). The aim of the study was to explore and understand the influence of applied voltage and influent COD concentration on concurrent H-2 production and P recovery in MEC. P was efficiently precipitated at the cathode chamber and the precipitated crystals were verified as struvite, using X-ray diffraction and scanning electron microscopy analysis. The maximum P precipitation efficiency achieved by the MEC was 95%, and the maximum H-2 production rate was 0.28 m(3)-H-2/m(3)-d. Response surface methodology showed that applied voltage had a great influence on H-2 production and P recovery, while influent COD concentration had a significant effect on P recovery only. The overall energy recovery in the MEC was low and ranged from 25 +/- 1 to 37 +/- 1.7%. These results confirmed MECs capability for concurrent H-2 production and P recovery. (C) 2017 Elsevier Ltd. All rights reserved.