Advanced treatment of landfill leachate from a sequencing batch reactor (SBR) by electrochemical oxidation process

Abstract

Biologically stabilized landfill leachate usually requires further removal of organic substances and ammonia nitrogen (NH3-N) before final discharge. In this paper, the advanced treatment of landfill leachate pretreated by sequencing batch reactor (SBR) via electrochemical oxidation was carried out in an electrochemical compartment reactor with oxide-coated titanium anode (Ti/TiO2-IrO2). The effect of voltage, chlorine content, initial pH value, and ferrous sulfate (FeSO4) on the removal efficiency of contaminants was investigated systematically. The removal efficiency of organic pollutants and ammonia nitrogen (NH3-N) increased with the increase of voltage, chlorine content and the addition of ferrous iron. The initial pH value has a different effect on the removal of COD and NH3-N. Compared with the traditional electrochemical oxidation, the process with Fe(II/III) is more efficient with low power consumption, and the removal efficiency of organic pollutant is slightly lower when Fe(II) is used. A lower power consumption of 16.6 kWh·(kg COD)–1 indicated the electrochemical oxidation with Fe(II) was a promising alternative for the advanced treatment of leachate.