Assessing the sustainability of composite liner systems for municipal solid waste landfills

Municipal solid waste landfills require liner systems to prevent leachate migration into the environment. Liner selection typically focuses on engineering performance, cost, and ease of construction, with limited emphasis on sustainability. This study assessed the sustainability of four composite liner systems using the triple bottom line approach, considering environmental, economic, and social impacts, along with technical equivalence based on leachate infiltration rates. The four systems analyzed were: (1) geomembrane (GM) over compacted clay liner (CCL) (GM/CCL), (2) GM over geosynthetic clay liner (GCL) (GM/GCL), (3) GM over soil mixed with lime and cement (SA) (GM/SA), and (4) GM over fly ash mixed with bentonite (FAB) (GM/FAB). Life cycle stages–material extraction, construction, monitoring, and disposal–were evaluated. The study focused on DeKalb County Landfill in DeKalb, Illinois, USA, with environmental impacts quantified using the Eco-Indicator 99 and TRACI methods in SimaPro 8.0.1. Results showed that GM/FAB was the most sustainable liner in terms of environmental impact and second in economic and social considerations. However, GM/GCL was the most preferred based on economic and social impacts.