A fed batch membraneless microbial electrolysis cell (MEC) was investigated for treating combined leachate and dairy wastewater at an applied voltage 0.8 V and hydraulic retention time (HRT) of 48 h. The COD (chemical oxygen demand) removal and energy recovery was tested by running several cycles of MEC with increasing ratios of leachate to dairy wastewater. With an increase in percentage of simulated leachate, MEC performance in terms of current generation, COD removal efficiency and hydrogen production showed a gradual decrease. A sudden drop in reactor performance was noticed when the concentration of leachate was increased from 14 to 16% corresponding to an increase in Organic Load Rate (OLR) from 23.89gCOD/m(3)/d to 24gCOD/m(3)/d. A continued operation of MEC at an OLR of 24gCOD/m(3)/d for ten continuous cycles resulted in COD removal efficiency of 73% and hydrogen production of 15 mL/L/d with current density of 10 A/m(2) and a power density of 80 mW/cm(2). (c) 2020 Elsevier Ltd. All rights reserved.