Background Although recycling rates have increased in Europe much waste is still landfilled, especially in Mediterranean and Eastern European countries. Landfills present long-term threats to soil, air, groundwater and surface water. This is mainly due to leachates, the liquid fraction continuously produced from solid waste that is dispersed when rainfall percolates through it. Approximately 10 m3 of leachate is generated per 115 tonnes of solid waste, and landfills can keep producing leachates up to 50 years after their closure. Although leachate composition varies, it is invariably hazardous to some extent – with potential ecotoxicological effects on terrestrial ecosystems and humans. In the absence of on-site treatment, leachate is circulated back into the waste, resulting in a more concentrated liquid that has a bad odour and attracts disease-spreading flies, creating bigger potential ecological and health risks and unpleasant working conditions. Without treatment, the leachate is also transported to sewer systems or wastewater treatment plants (WWTPs). Due to its high organic and ammonium concentrations, leachates cause extra loading in treatment plants, requiring additional chemical and energy consumption to comply with effluent limits. Moreover, due to the high metal content in leachate, the sludge generated may not be suitable for agricultural applications. The problems are most acute in smaller WWTPs, where leachate is less diluted with municipal sewage. Leachate treatment techniques remain expensive and technically inefficient. Objectives The LIFE LEACHLESS project aims to demonstrate the technical and economic feasibility of an innovative and cost-efficient technology for leachate treatment, based on solar evaporation/condensation and forward osmosis. The project prototype will have a treatment capacity of 15 m3/day of leachate, and will be tested in Botarell (Spain) and Athens (Greece). The new technology permits the on-site treatment of leachate, removing 100% of the pollutants (including emerging pollutants) and avoiding costly and energy-consuming effluent transport to municipal WWTPs. The final solid residue (sludge) will be used in the manufacture of ceramic products as a waste-to-resource strategy. The project promotes water resource management in line with the Water Framework Directive by enabling managers of landfills and waste treatment centres to achieve good qualitative and quantitative status for effluents. By reducing energy consumption and valorising the sludge, the project is also fully in line with the objectives of the EU 7th Environment Action Programme (EAP) regarding the transformation of the EU into a resource-efficient and low-carbon economy; the EAP also prioritises the more efficient use of water resources. Finally, the project will improve the operation of landfills and reduce their associated environmental impacts, thus contributing to the Landfill Directive. Expected results: A high-quality final effluent obtained that is 100% free of pathogens and xenobiotic compounds and that can be reused or discharged into watercourses; Reduced cost of leachate treatment by over 80%, when comparing with a traditional leachate treatment plant, by using solar radiation, biomass and residual heat as energy sources; 80 to 90% reduction of the environmental impact associated with leachate streams proceeding from waste disposal in landfills or waste treatment centres; Elimination of the need to transport leachate to municipal WWTPs and thereby eliminate associated transport costs, carbon footprint and the risk of emerging pollutants entering the overall water circuit; A technology applicable in EU countries with the highest volume of municipal waste sent to landfill, which also generate the most leachate. These countries (e.g. Spain, Greece, Italy, Portugal and Malta) are among those with the higher number of sunlight hours, which favours the operation of the technology; Valorisation of 100% of the by-products generated in the process. The amount of sludge generated as a by-product is very low (1-3% of the total volume of leachate), but it can be valorised for the ceramic industry; 60% reduction of the leachate storage reservoir size in landfills and waste treatment plants, thus removing pollution at source; A network of contacts for disseminating good practices and project results, and extending the project scope; Two replication studies for transferring the project findings in two ‘follower facilities’ (in Spain and Greece) and one in Pordenone’s landfill in Italy when the project is completed; Authorities able to increase the competitiveness and improve environmental legislation through better management of leachate; and Dissemination of the project results at national and international level through the dissemination plan and networking activities.