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Keywords:

  • COD;
  • landfill leachate;
  • electro-coagulation;
  • iron electrode;
  • electro-Fenton process

Abstract

The removal of chemical oxygen demand (COD) from landfill leachate by electro-coagulation (EC) using iron sacrificial anode has been investigated. The process performance is analyzed in terms of COD removal efficiency and the important cost-related parameters such as electrode and energy consumptions, as a function of initial pH, conductivity, current density, and operation time. The optimum COD removal (65.85%) was obtained with typical operating conditions: current density, 30 mA/cm2; operation time, 180 min; conductivity, 16.4 ms/cm; and initial pH, 6.54. At these conditions, the electrode and energy consumptions during the electrolysis were determined as 0.418 kg COD/kg Al and 11.092 kWh/kg COD, respectively. In addition, the EC and Fenton processes are applied together referred to as the electro-Fenton process in the literature for the removal of COD from landfill leachate and effect of operation time and hydrogen peroxide concentration is examined. The process was very fast in the first 15 min, and then it slowed down till it was complete in 60 min. An optimum COD removal efficiency of 74.21% was obtained at 5000 ppm hydrogen peroxide dosage and 60 min. © 2010 American Institute of Chemical Engineers Environ Prog, 2012