Application of life cycle assessment for solid waste management at a higher education institution

Waste is an increasingly significant challenge in climate sustainability, contributing 3-5% of the total global greenhouse gas emissions. As institutions and organizations strive to reduce emissions and set sustainability targets, the waste sector offers a valuable opportunity to reduce environmental impacts. To begin effective emission reduction efforts, accurate accounting to identify hotspots is needed to make informed decisions. This case study addresses the gap in accounting Scope 3 waste emissions at a university level at the University of Wisconsin-Madison using a process-based lifecycle assessment approach and comparing results with other widely used Scope 3 models. Results indicated that landfilled municipal solid waste consistently contributed most significantly to global warming potential and eutrophication potential impacts, followed by comingled recycling. Scrap metal recycling and aluminum provided the largest offsets within the waste stream. The uncertainty analysis showed wide confidence intervals, and the sensitivity analysis identified certain categories as highly influential. When compared with the standard Scope 3 calculation tools, the total emissions estimated through the process-based LCA were most like those produced by the Economic Input-Output life cycle assessment and the Sustainability Indicator Management Analysis Platform models. With respect to the results of the process-based LCA on a per kilogram of waste handled basis the global warming potential impacts were 0.47 kg CO2e (2020), 0.41 (2021), 0.43 (2022), and 0.46 (2023). Consequently, on a per kilogram of waste handled basis the EP impacts were 8.47∗10^-3 kg N eq (2020), 7.56∗10^-3 (2021), 7.50∗10^-3 (2022), and 8.17∗10^-3 (2023).