Study of the treatment of leachate after biodigestion using Electro-fenton method

Abstract

Leachate contains many non-biodegradable organic compounds and nutrients with high concentrations, especially from urban waste landfills with long operating times (> 10 years), which affects the human health and environmental quality. Electro-Fenton is one of the advanced oxidation processes (AOPs) that has been recently studied for the treatment of many persistent organic compounds in water. In this study, post-biological leachate (continuous flow biological tank) was treated using Electro-Fenton method with heterogeneous catalysts as Iron (II) Sulfide and Iron Oxide on two electrodes Ti/IrO2-Ta2O5 and Ti/RuO2. The effect of different pH conditions on the pollutant removal efficiency in landfill leachate was studied. The results show that Ti/IrO2-Ta2O5 electrode and Iron (II) Sulfide catalyst obtain better leachate treatment performance than the others under the same experimental conditions. The heterogeneous Electro-Fenton process was capable of removing 71% of chemical oxygen demand (COD), 88% of total organic carbon (TOC), 89% of total nitrogen (TN), 93% of ammonium nitrogen N-NH4 + and 99% color at Ti/IrO2-Ta2O5 electrode and Iron (II) Sulfide catalyst at a pH 3, current density 333 mA/cm2 after 90 minutes of electrolysis. The results showed that the Electro-Fenton method capable effective treatment of pollutants in the post-biological leachate in the future.