Post treatment of ICEAS-biologically landfill leachate using electrochemical oxidation with Ti/BDD and Ti/RuO2 anodes

Leachate is known with high concentration of organic substances and nitrogen, which are extremely toxic to the environment. Recently, electrochemical oxidation has received much attention on account of its low cost, feasibility, environmental friendliness, and excellent in contaminants removal in wastewater. The present study reported the first time treatment of biologically leachate (after continuous flow sequencing batch reactor (CFSBR) or Intermittent Cycle Extended Aeration System (ICEAS) digestion) electrochemical oxidation using Ti/BDD and Ti/RuO2 anodes. Effects of varying operational conditions of the electrochemical oxidation process: current density, reaction time, pH, and flow rate on the pollutant removal efficiencies and energy consumptions, were studied. Final results revealed that low pH favors high organic substance removal efficiencies, but restricts low ammonium removal efficiencies, and vice versa. When using a Ti/BDD anode, COD, TOC, NH4+-N and total Nitrogen (TN) elimination rates achieved highest were 95.17%, 91.89%, 81.18% and 63.54%, respectively; while, with Ti/RuO2 anode, they were 92.57%, 78.76%, 97.85% and 72.12% at 83 mA cm(-2) and 8 h. Ti/BDD anode showed less energy consumption and better pollutant removal efficiencies than the Ti/RuO2 anode, except for the NH4+-N and TN parameters. After treatment, the effluent matched with the Vietnamese discharge standards for landfill leachate effluent QCVN 25:2009/BTNMT. (C) 2020 Elsevier B.V. All rights reserved.