Leachate is known as a vigorous wastewater in terms of its organic matter and ammonia content. It is a major problem for municipal solid waste (MSW) landfill. It posed threat to surface water and groundwater. This study focusing on the removal of ammonia-nitrogen (NH3-N) by coagulation on a raw leachate sample taken from Rimba Mas municipal solid waste (MSW) landfill. The landfill leachate is tested for COD, colour and NH3N. Morphological features of calcium oxide are studied using XRF and SEM. Optimum dosage of coagulant for ammonia nitrogen removal from MSW leachate is investigated. The method used in this research was coagulant-flocculation treatment: jar test apparatus. The coagulant was conducted using hydrated lime, Ca(OH)2 with varying amount of coagulant to find the optimum dosage for ammonia nitrogen removal. A raw leachate sample taken from Rimba Mas landfill was treated with a different amount of hydrated lime (2, 4, 6, 8, 10 g/L) and 0 as a control to investigate the removal of ammonia nitrogen. The results showed that the pH of leachate (9.09) after treated with hydrated lime is increased when the dosage of hydrated lime is increased. Results showed that the best value of removal efficiency from leachate of colour, COD and NH3N were 54.70%, 56.22% and 85.25% respectively. We can conclude that as the optimum dosage increases, removal efficiency is increases.
