This book presents a review of the current status of the treatment of leachates generated in sanitary landfills (RESA) in Colombia, taking into account the negative environmental impact generated as a result of the discharge of leachates, which directly affect water sources. A diagnosis was carried out that showed the existence of 144 RESA in Colombia. In addition, based on the application of a filter that took into account the variables of number of inhabitants, number of tons of waste generated and flow of leachate generated, it was determined that 17 of these WASW were suitable as an object of study. Of these, according to the applicable regulations and the latest characterizations carried out by control entities, all are above the permissible limits for leachate discharge, generating negative impacts on some bodies of water mainly due to the presence of highly toxic pollutants such as cadmium, chromium, lead, bromine, zinc and mercury. Based on the above, the most efficient treatments for the removal of this type of pollutants currently used in Colombia were compared.