Australian Journal of Basic and Applied Sciences, 7(8): 263-268, 2013 ISSN 1991-8178 Corresponding Author: Zawawi Daud, Faculty of Civil and Environmental Engineering E-mail: zawawi@uthm.edu.my 263 Optimization of COD and Colour Removal From Landfill Leachate by Electro-Fenton Method 1 Zawawi Daud, 1 Nur Fatihah Muhamad Hanafi, 2 Halizah Awang 1 Faculty of Civil and Environmental Engineering 2 Faculty of Technical and Vocational Education Universiti Tun Hussein Onn Malaysia, 86400 Batu Pahat, Johor, MALAYSIA Abstract: The contamination of untreated leachate effluent is a potential source to effect of soil, surface and groundwater.In this study, the treatment of landfill leachate by electro-Fenton (EF) method was studied. The objectives of the study are to determine the optimum current density, the optimum treatment time, the optimum pH, the optimum hydrogen peroxide (H 2 O 2 ) dosage and the optimum ferrous sulphate heptahydrate (FeSO 4 •7H 2 O) dosage of landfill leachate samples using aluminium electrode. From the results, it is verified that electro-Fenton method (EF) can used efficiently to degrade leachate organics. The best removal efficiencies were obtained when current density value is 200 A/m 2 , treatment time is 25 min and pH value is 4. The optimum dose of hydrogen peroxide (H 2 O 2 ) is 800 mg/L which was obtained 78% and 96% of COD and colour removal efficiency respectively. The optimum ferrous ion (Fe 2+ ) is 1000 mg/L which was obtained 75% and 94% of COD and colour removal efficiency respectively. Key words: landfill leachate, electro-Fenton, COD, colour, aluminium electrodes INTRODUCTION Recently, the industrial and commercial growth in many countries has been affected in the increases of both municipal and industrial solid waste generations. Percentage composition of solid waste is different between areas because it is influenced by several factors such as location, community attitudes, frequency of collection, legal systems, population characteristics, socio-economic and lifestyle. Up to 95% of solid waste generated worldwide is currently disposed in landfill (Bohdziewicz and Kwarciak, 2008). Leachate is a high strength wastewater which has been recognized as one of the most concerned pollution sources. Landfill leachate is the hazardous and heavily polluted wastewater, formed as a result of percolation of rainwater and moisture through solid waste in the landfill site (Bohdziewicz and Kwarciak, 2008; Amuda, 2006). Landfill leachate contain high load of organic matter, high content ammonia nitrogen, heavy metals, inorganic salts and chlorinated organic. The composition of leachate depends on age of landfill, hydrogeology of the site, quality and quantity of solid waste, site climate, season, biological and chemical processes occurring in the landfill and the amount of precipitation and percolation of rainwater, landfill morpology, waste depth, landfill condition and operation of facilities (Li et al., 2010). Lately, advanced oxidation processes (AOPs) have been studies because of their ability to generate radical intermediate compounds. The radical intermediate compounds contain highly oxidative species which are capability to oxidize toxic pollutants into harmless species. Technologies of oxidation processes such as Fenton oxidation, photo-oxidation and electro-oxidation are recurrently applied to increase efficiency of electro-chemical methods in order for degradation and decolourization of wastewater. Today, there has been an increases focus on the use of electro-chemical methods which can produce OH• as the main oxidizing agent ( Brillas et al., 2000; Kraft et al., 2003; Mohajeri et al., 2010). One of the promising of ability to degrade pollutants effectively is electro-Fenton (EF). Electro-fenton (EF) method has been applied with combination of fenton oxidation and electrochemical are carried out together and each of them is a powerful treatment method (Atmaca, 2009; Brillas and Casado, 2002; Mohajeri et al., 2010). This process is use of electrically assisted Fenton reaction will produce more OH• radicals and the oxidation of the organics to CO 2 can be enhanced in the same period (Mohajeri et al., 2010; Liu et al., 2007). Normally, there are two different electro-Fenton (EF) applications. In the first one the Fenton’s reagents (Fe (II) and H 2 O 2 ) are added to the reactor from outside and inert electrodes having high catalytic activity are used as anode material. In the second one, H 2 O 2 is added from outside and Fe (II) is provided from sacrificial cast iron anodes. In the electro- Fenton process, hydrogen peroxide (H 2 O 2 ) is produced in the required amount from the electrochemical reduction of oxygen. Hydroxyl free radical is generated by interaction of H 2 O 2 with ferrous salts namely the Fenton reagent. The objective of this study was to examine the efficiency of electro-Fenton process for removal of COD and colour from landfill leachate. The experiments involved with the determination of current density, treatment time, pH, dose of hydrogen peroxide (H 2 O 2 ) and ferrous sulphate heptahydrate (FeSO 4 •7H 2 O) on identification