Introduction: Leachate contamination is one of the major problems caused by landfilling. high concentrations of COD and existence of toxic compounds in landfill leachate and makes it difficult for direct biodegradation. This study aims to optimize the operational parameters of electro-Fenton process for COD removal from landfill leachate in Tehran.

Materials & methods: The experiments were performed at bench scale using a batch reactor. Treatment of landfill leachate by electro-Fenton (E-Fenton) method was carried out in an electrolytic reactor. Moreover, the effect of operations such as reaction time, initial pH, initial H₂O₂ concentration, electrical current on the efficiency of E-Fenton process were investigated.

Findings: The results revealed that (E-Fenton) process can be used for the efficient treatment of landfill leachate applying the proper operating conditions. The best removal efficiency was obtained within 30 min with constant DC current value of 4.9 mA /cm², H₂O₂ concentration is 1.5gL⁻¹ and the initial pH value is 3. COD removal of 87.2% was obtained in these operational conditions.

Discussion & conclusions: According to the obtained results, E-Fenton technology is able to produce sufficient amounts of advanced oxidants in situ to degrade great COD of leachate. In addition, (E-Fenton) process has been reported as one of the most appropriate pretreatment systems for degradation COD of leachate concentrates. This process  improve biodegradability of the landfill leachate.