The composition of landfill leachate is complex due to the conditions within a landfill and treatment methods must be based on the actual characteristics of the leachate. This book, therefore, investigates various operating conditions for minimizing required Fenton reagents and sludge disposal and maximizing chemical oxygen demand as well as colour removal from the leachate. A number of combined treatment processes are also developed in order to maximize the removal of organic compounds through the most appropriate one. Samples were collected from Matuail landfill site, one of the major landfill sites of Dhaka City Corporation. Conventional extended aeration process which is widely practiced for the present leachate treatment system of Matuail landfill site, has not achieved the satisfactory level of organic content removal due to a great extent of non-biodegradable organic compounds contained in landfill leachate. This research has suggested that not only biological aeration is enough to treat Matuail landfill leachate to the desired level but also further chemical treatment with Fenton reagent gives satisfactory results for treating the heavily polluted leachate.