Innovative electrochemical system for landfill leachate treatment: Determination of treatment efficiency on laboratory-scale reactor

Landfill leachate wastewater contains abundant recalcitrant organic contaminants, nutrient, and ionic compounds. This wastewater recently provides challenges regarding treatment efficiency, particularly when implementing conventional biological processes. One of the innovative technologies to enhance the efficiency is electrochemical processes combined with possible photovoltaic (PV) cell as a renewable and sustainable energy supply. This study aims to determine the removal efficiency of organic compounds (as COD), ammonium-nitrogen, and dissolved solids contained in leachate using a laboratory-scale electrochemical reactor. The reactor was separated by ionic membranes with two batch recirculation systems, i.e., concentrate, and anode-to-cathode recirculation at a constant flow rate of 5 mL.sec-1. Borondoped-diamond anode and stainless-steel cathode were used in the reactor, by applying a constant cell voltage of 20 and 25V for 8 hours without using PV and 6 hours using PV. The removal efficiency was determined each hour on 2-L sample volume with three different contaminant loads. At the final effluents of treatment using PV, the COD removal was 44-53% (i.e., 0.7-2 g), achieved between 0.73-1.75 Ah.L-1 (i.e., 40.51-177.63 and 50.49-77.75Wh.g-1 COD at constant voltage of 20V and 25V, respectively). Similarly, the ammonium removal was up to 76% (i.e., 0.5 g ~ 442 Wh.g-1 NH +). At higher contaminant loads, the energy required for electro-oxidation was decreased due to the increased conductivity. Therefore, this electrochemical system is adequate as an alternative treatment of “strong leachate”, applying sustainable energy supply.