COD, NH3 and color removal from landfill leachate

Abstract

Leachate is the term used for the liquid produced by the action of “leaching” when water percolates through any permeable material other than through landfilled wastes. Leachate causes harm in many ways. Special care is required for their efficient treatment and disposal. Coagulation/flocculation is an essential process in water and industrial wastewater treatment. The aim of this study was to examine the percentage removal of chemical oxygen demand (COD), ammonia (NH3) and colour using coagulation-flocculation process as a pre-treatment followed by the effect of ZnO as a final treatment. Jar-test experiments were employed in order to determine the optimum conditions for coagulant dosage and pH. Moringa oleifera was tested as a coagulant which has coagulant properties for treating water and wastewater. The optimum dosage of Moringa oleifera was found to be effectively in treating leachate at 20 mL with the optimum pH was found at pH 2. The optimum condition was applied to determine the removal of COD, NH3 and color using the addition of zinc oxide (ZnO) as final treatment under sun exposure. Addition of ZnO as a catalyst was found to give a significant effect and enhancing the removal of COD, NH3 and color from landfill leachate samples. The optimum dosage of ZnO was found at 0.2g with the optimum contact time was found at 60th minutes. The results indicate that Moringa oleifera and ZnO can be used effectively in leachate treatment systems, especially for removing chemical oxygen demand (COD), ammonia (NH3) and colour.