Waste Flow, Recycling, and Greenhouse Gas Emissions: a Case Study of the Comparative Environmental Impact of Recycling Approaches on a College Campus

Abstract

Municipal solid waste flow was modeled and measured at the U.S. Naval Academy to understand not only the movement of waste, but also the policies and economic incentives that have led to the current waste management plan at the Academy. The study contains four primary thrusts: regulatory policies, waste production and recycling levels, collection and sorting processes, and disposal and material recovery. Waste hauling data for a one-year period in 2017-2018 showed that the institution generated approximately 300 tons of total waste each month and recycled approximately 11-15% of that waste. From directly measuring waste across campus, approximately 36% of the non-recyclable waste stream contains recyclable materials. Most recyclable materials that ended up in the non-recyclable waste stream were plastics and cans, and came from academic spaces. However, a test academic space that gave access to waste bins only conjoined with recycling bins showed a substantial reduction in recycling infiltrating the non-recyclable waste stream. The study also shows how the handling of waste has evolved over recent years. Since the mid-2000s, the Academy has shifted to relying on contractors to sort and transport waste. Currently, five private contracting agencies are utilized in the waste flow stream after materials leave the Academy. To assess environmental impact, a life cycle assessment model was constructed based on the movement of waste to estimate the possible effects of the current recycling program on carbon equivalent emissions. The results indicate that current practices result in over 500 metric tons of carbon equivalent savings over the long-term during the one-year measurement period. The model also shows that by reducing recycling infiltrates into the waste stream, an additional 1000 metric tons of carbon equivalent savings are possible. Economic incentives were evaluated at each of the four sections of the waste process model, and analysis suggests that focusing on behavioral change strategies at the waste generation and initial collection and sorting levels holds the best promise for increasing levels of recycling, reducing landfilled waste, and reducing net carbon emissions in accordance with DOD policy goals.