Environmental and economic implications of U.S. postconsumer plastic waste management

Abstract

• US post-consumer plastic waste is explored using integrated process-based approach. • Low collection rates are economically unfavorable and do not lead to GHG savings. • Improvements in energy recovery, fuel recovery and recycling processes are needed. • A business-as-usual increase in collection volume does not lead to intended savings. • Design for recycling practices needed to maximize end-of-life recovery. With only 8.4% of end-of-life plastics collected for recycling in 2017, management of postconsumer plastic waste in the U.S. has raised significant concerns. We present an integrated approach to assess the environmental benefits and economic implications of plastic waste management by interfacing collection and sorting with process-based treatment models for energy recovery, fuel recovery and mechanical recycling. Three composite treatment scenarios are analyzed under various techno-economic contexts to understand the key drivers of greenhouse gas (GHG) emissions/savings and economic viability. At current collection volumes, both net GHG savings and net annual revenue are unfavorable. Scaling collection rates from the current level to a hypothetical 100% exposes inefficiencies beyond the collection bottleneck and results in net GHG emissions. We find that a business-as-usual increase in collection volume alone would be insufficient to offset GHG emissions and is uneconomical. We quantify the potential found in improving waste-to-energy efficiencies, developing high-yield plastics-to-fuel pathways and incorporating design for recycling considerations. From an economic standpoint, external market factors such as sale price of electricity, fuels and virgin resins are critical to financial viability of treatment processes. This analysis also allows us to appropriately assess the magnitude of investment and type of policy efforts needed to address the problem. To effectively collect and treat 100% of all U.S. postconsumer plastic waste, an upfront investment of 17–21 Billion USD is estimated. This approach underscores the importance of a systems perspective that acknowledges the complexity of the postconsumer plastic waste stream to sustainably achieve plastic waste management objectives.