Life cycle assessment of a shrub willow evapotranspiration cover compared with conventional clay and geosynthetic covers in Upstate New York

Abstract

The establishment of landfill covers consumes substantial amounts of fuels and materials that contribute to greenhouse gas emissions and fossil fuel depletion (FFD). This study compared the global warming impact (GWI) and FFD of a shrub willow evapotranspiration (ET), conventional clay, and geosynthetic cover using life cycle assessment (LCA). The willow ET cover is a carbon-negative system with a total GWI of -13,206 kgCO_2eq ha^-1 over 30 years, while the GWI of clay (194,916 kgCO_2eq ha^-1) and geosynthetic covers (260,212 kgCO_2eq ha^-1) were substantial. Willow's ability to store carbon in coarse roots and stools creates the opportunity for negative carbon emissions. The FFD impact of the willow ET cover (75,303 MJ surplus ha^-1) is 4.7 times lower than the clay cover and 7.7 times lower than the geosynthetic cover. Sensitivity and uncertainty analyses indicated that the GWI of the willow ET cover was less than zero for all scenarios, and the GWI and FFD of the geosynthetic cover were the highest. Willow ET covers can protect human health and the environment, reduce greenhouse gas emissions by sequestering carbon, and provide a source of wood chips that could be used for renewable energy or other applications.

Keywords: Clay cover; Evapotranspiration; Evapotranspiration cover; Geosynthetic cover; Global warming impact; Landfill covers; Life cycle assessment; Phytoremediation, Green remediation; Shrub willow; Willow, Salix.