Effect of Flow Rate on Electrochemical Oxidation of Landfill Leachate Using DSA and BDD Anode

Abstract

The leachate produced in municipal mixed waste landfill contains mostly organic pollutants in various forms. Biological treatment that popularly applied for the treatment only capable of removing biodegradable portion of the organics whilst the recalcitrant parts will leave the system untreated. Therefore, a pretreatment prior to biological process to increase biodegradability of leachate is essential. The physicochemical method such as electrochemical oxidation is an appropriate pretreatment alternative because it has high efficiency in degrading such pollutants. The purpose of this study was to examine the effect of flow rate (1.5 and 5 mL s-1) and anodes (boron-doped diamond (BDD) and dimensionally stable anode (DSA)) on the efficiency of electrochemical oxidation process to degrade leachate. The parameters analyzed were COD, BOD, ratio of BOD5/COD (biodegradability index, BI), TDS and pH. The results showed that the increase in BI when BDD and DSA used were 0.386 and 0.179, respectively. The best COD removal was achieved by BDD and DSA at current density of 30 mA cm-2 with the flow rate of 5 mL s-1. BDD could remove 83 % COD (1.56 g) while DSA 68 % (1.08 g) with specific energy consumption of 0.00268 kWh g-1 and 0.00186 kWh g-1, respectively.