Comparison of carbon dioxide emissions for two landfill capping layers

Geosynthetics are commonly employed in landfill applications to provide containment in the capping layer, also referred to as a cover system. This paper presents a case study that compares the CO2 emissions produced from a compacted clay landfill cap as compared to one incorporating geosynthetics. The Life Cycle Analysis boundaries set for this case study were of cradle to end of construction, and including all processes from sourcing of materials through to the end of construction. As-built data provided by the contractors and manufacturers was used to calculate the carbon footprint of each solution. Comparison showed the geosynthetic solution to be more sustainable. However, deficiencies in standard database values revealed inconsistencies and a value for the embodied carbon of clay was calculated using primary data. The embodied carbon value calculated from primary data was much lower than the one initially employed and hence made the clay solution more sustainable where materials were locally available.