The environmental impacts of municipal solid waste landfills in Europe: A life cycle assessment of proper reference cases to support decision making.

In Europe, 23% of the generated municipal solid waste (MSW) was landfilled in 2017. Despite the landfill targets which define waste and landfill requirements, there is still high variability in the waste management performance between EU Member States. Aim of the study was to give an overview of the variability of environmental impacts of MSW sanitary landfills in Europe in relation to the different levels of implementation of the requirements. Life cycle assessment (LCA) was adopted as tool to define the impacts of the different landfill conditions over a 100-year period. Based on previous studies, consistent methodological choices were made to allow comparability of the results. Four reference cases were defined based on average bulk MSW compositions to represent the European conditions, with L values of 18, 61, 90 and 138 [m CH/t waste]. Furthermore, multiple scenario analysis was used to increase the relevance of the assessment and address the variability of site-specific factors, such as waste composition, climatic conditions and landfill management, which influence the impacts of landfills. Results of the study showed the range of potential impacts in Europe in relation to the variation of influencing factors, with values for climate change ranging from 124 to 841 kg CO2 eq., and with environmental savings obtained for categories such as ecotoxicity and human toxicity for scenarios with landfill gas - to - energy (LFGTE) solutions. The results emphasized the dependence of landfill impacts on waste composition, but also on the LFG treatment and climatic conditions. The outcome of the study also highlight how low amounts of biodegradable fractions reduce the impacts of landfills, as well as their variability in relation to leachate production rates or LFG treatment solutions. Therefore the overall results support the current targets and requirements reported in the Waste Directive 2008/98/EC, Circular Economy package and Landfill Directive 1999/31/EC.