An incremental model to assess the environmental impact of cap cover systems on MSW landfill emissions
Résumé
Landfill cap covers are designed to contain fugitive methane emissions and to prevent uncontrolled leachate infiltration. The objective of this paper is to propose a method for assessing their impact on the mitigation of landfill greenhouse gas emissions using a new dedicated model (IMAGE-Landfill) that takes into account the different steps of landfill management history as well as the incremental methane production from the different cells. In particular, different collection and oxidation efficiencies are considered depending on the landfill operation, on its life step and on the chosen cap cover system. Two different theoretical single cell case studies and one real-scale landfill were used to calibrate the IMAGE-Landfill model. The results highlight that, depending on the selected cap cover lining system, the potential greenhouse gas emissions may be divided by a factor 2.5-7, even if no energy is recovered from the collected methane. This model is a useful tool for landfill operators to model methane production, but also to select the most appropriate cover type for each step of the landfill lifetime. Finally, this research appeals for a better consideration of environmental impacts when designing landfill barriers.