Leachate generated from an old landfill in Taiping, Perak, Malaysia contains high colour, COD, iron and ammoniacal nitrogen. Activated carbon limestone mixture was used as a primary treatment process. More than 86 of colour and COD, 95 of iron, and 48 of ammoniacal nitrogen were removed by a mixture of activated carbon and limestone (15:25 by volume) in the batch study compared with 70, 80 and 90 respectively, by column study on the first five days. Both Langmuir and Freundlich isotherms had fitted well with the experimental data. The adsorption kinetics followed the pseudo-second-order model indicating that chemisorption or ion exchange was the rate-controlling step in the adsorption. Copyright © 2009, Inderscience Publishers.