The consideration of long-term emissions from landfills within life-cycle assessment

Within a product system of a life-cycle assessment (LCA), solid waste landfills should be treated as processes, because they are considered to be a part of the technical system. Hence, their inputs and outputs should be included in the life-cycle inventory analysis and evaluated within the life-cycle impact assessment. The aim of this paper is to discuss the consideration of emissions from solid waste landfills within the LCA framework and to investigate the uncertainties in existing modelling approaches. Based on this analysis the main limitations are discussed and recommendations for incorporating long-term emissions from landfills in LCA are made. It is emphasized that the lack of consideration of spatial and temporal characteristics of long-term emissions turns out to be an important source of uncertainty when modelling the environmental impact of landfills. For toxicity categories in particular, the life-cycle impact assessment might be the dominant source of uncertainty. However, in order to understand the reliability of LCA results with respect to landfill emissions, quantitative uncertainty should be routinely included in LCA studies and sources of uncertainty need to be thoroughly discussed.