In this study, the feasibility of electrochemical oxidation of the aqueous oxalic acid solution has been investigated in an electrochemical reactor with SPE and simultaneous hydrogen production has been observed. Experiments were conducted to examine the effects of applied current density, flow rate of solution, pH of the solution, the concentration of supporting electrolyte, the temperature of the solution, types of the electrode and membrane material on removal efficiency. As a result of the studies oxalic acid as COD at the original pH can be treated to meet discharge limits at ambient temperature without any pH adjustment with low energy consumption. COD removal efficiency of 97% has been achieved by using titanium oxide coated with iridium oxide as anode. Since there is no need to use liquid electrolyte in this type of reactor, aqueous oxalic acid solution can be oxidized without adding any supporting electrolyte such as Na2SO4. (C) 2008 Elsevier B.V. All rights reserved.