A.A. Halim et al. Proceeding of The International Seminar on Chemistry 2008 (pp. 722-728) Jatinangor, 30-31 October 2008 722 Ammoniacal nitrogen and COD removal from semi-aerobic landfill leachate using carbon-mineral composite adsorbent Azhar Abdul Halim* 1 , Hamidi Abdul Aziz 2 , M. Azmi M. Johari 2 , Kamar Shah Ariffin 3 1 Environmental Health Program, Faculty of Allied Health Sciences, Universiti Kebangsaan Malaysia (KKL), Jln. Raja Muda Ab. Aziz, 50300 Kuala Lumpur 2 School of Civil Engineering, Engineering Campus, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang, Malaysia 3 School of Materials and Mineral Resources, Engineering Campus, University Science Malaysia, 14300 Nibong Tebal, Penang, Malaysia *e-mail: azhar_abdul_halim69@yahoo.com Abstract Chemical oxygen demand (COD) and ammoniacal nitrogen were the problematic parameters in landfill leachate treatment. Combination of activated carbon and zeolite as filter medium may reduce this problem. This study was conducted to find treatment alternative by combining the low cost adsorbent such as limestone and rice husk carbon waste and ordinary adsorbent media, activated carbon and zeolite as a single media. All the adsorption media was crushed and sieved to a particle size of 150μm. The optimum ratio was predicted by mean of a batch equilibrium experiments. Ordinary Portland Cement (OPC) was used as a binder at 30 percent by weight. Activated carbon and rice husk carbon was grouped as a hydrophobic media where the optimum ratio was 1:1. Zeolite and limestone was in hydrophilic media group which the best ratio was 3:1. The ratio for hydrophilic and hydrophobic media had been chosen as 7:1 accordingly to adsorption behavior of ammoniacal nitrogen and organic constituents (COD) to the media. The optimum conditions for adsorption batch study were found at pH 7, 200rpm in shaking speed and 90 minutes of contact time. The results showed that the equilibrium data were fitted and favorable adsorption by both of the Langmuir and Freundlich isotherms while Langmuir isotherms was slightly better fitted for ammoniacal nitrogen and Freundlich was good for COD removal in term of regression coefficients (R 2 ). Langmuir adsorption capacities (Q) for ammonia and COD were 43.47mg/g and 256.41mg/g respectively while Freundlich (K F ) were 0.00135mg/g and 0.03891mg/g respectively. Keywords: Composite adsorbent, leachate treatment, physico-chemical treatment, semi-aerobic leachate Introduction Leachate is a liquid formed primarily by the percolation of precipitation water through the open landfill or through the cap of the completed site (Senior, 1995). Leachates may contain large amounts of organic contaminants which can be measured as chemical oxygen demand (COD) and biological oxygen demand (BOD), ammonia, halogenated hydrocarbons suspended solid, significant concentration of heavy metals and inorganic salts (Trebouet et al., 2001; Bagchi, 1990). If not treated and safely disposed, landfill leachate could be a potential source of surface and ground water contamination, as it may percolate through soils and subsoils, causing pollution to receiving waters (Tatsi, et.al. 2003). Most of the landfills do not have leachate treatment facilities. Leachate from this improperly designed landfill may pollute our environment, especially the surface and groundwater. The two major problem of leachate is organic contaminant and ammoniacal nitrogen. Biological treatment of landfill leachates have been shown to be very effective in removing organic matter in early stages (Berruetta & CastrillÓn, 1992) when BOD/COD ratio of the leachate has a high value. This ratio decreases with the age of the landfill (Rodriguez et al., 2000) and the process is less effective with time (Mendez et al., 1989), due to the major present of refractory organic matter. In recent years, due to cost-effectiveness, the great interest has been focused on the preparation of low cost adsorbents as a substitute or reduces activated carbons consumptions. The development of modern technology requires a continuous search for new adsorbents. Carbon–mineral composite adsorbents can be considered as a new type of adsorbent, which may have structures and adsorption properties different from the individual components (Leboda, 1992 & 1993). In the literature mechanical mixing of carbon and mineral adsorbents, addition of carbon particles to the mineral sol before gelation prepares carbon mineral composite adsorbents, and carbonization of organic substances previously bonded to the mineral adsorbent (Leboda, 1992). ISBN 978-979-18962-0-7