Review on Landfill Leachate Treatments

Problem Statement: Sanitary landfilling is the most common way to eliminate solid urban wastes. An important problem associated to landfills is the production of leachates. This study is a review of landfill leachate treatments. Approach: The advantages and disadvantages of the various existing leachate treatments discussed under the items: (i) Leachate channeling (combined treatment with domestic sewage, recycling) (ii) Biological processing (aerobic and anaerobic) (iii) Chemical/physical treatment (flotation, coagulation/flocculation, chemical precipitation, adsorption, ammonium stripping, chemical oxidation, ion exchange and electrochemical treatment) (iv) Membrane filtration (microfiltration, ultrafiltration, nanofiltration and reverse osmosis). Conclusion: The major fraction of old or biologically treated leachate was large recalcitrant organic molecules that are not easy removed during biological treatment. So that, in order to meet strict quality standards for direct discharge of leachate into the surface water, a development of integrated methods of treatment, a combination of biological, chemical, physical and membrane process steps, were required. Today, the use of membrane technologies, more especially Reverse Osmosis (RO), either as a main step in a landfill leachate treatment chain or as single post-treatment step had shown to be an indispensable means of achieving purification.