You are here:
Developing Life Cycle Models for Managing Plastics – Understanding Material Flows, Processes, and Potential Consequences
Citation:
Smith, Raymond L. Developing Life Cycle Models for Managing Plastics – Understanding Material Flows, Processes, and Potential Consequences. Board of Scientific Counselors, Sustainable and Healthy Communities, Waste and Sustainable Materials Management Research, NA, October 28, 2021.
Impact/Purpose:
The work presented is based on research aimed at supporting Sustainable Materials Management in EPA’s Office of Resource Conservation and Recovery. Municipal Solid Waste (MSW) is a post-consumer material stream where certain components are recycled. Determining the current flows of plastics through Material Recovery Facilities (MRF), recycling processes, and conversion into products can raise awareness of these streams of interest. From the analysis one can consider where post-consumer plastic ends up. In this work Polyethylene Terephthalate (PET) was studied as an example. The analysis considers what fraction is recycled? What products are recycled? And into what products is it made? Knowledge about these flows can support efforts in Sustainable Materials Management, where individual generation, recycling, composting, combustion with energy recovery, and landfilling flows are tracked within the non-hazardous waste management hierarchy.
Description:
As efforts are made towards establishing a circular economy that engages in activities that maintain resources at their highest values for as long as possible, an important aspect is understanding the systems which allow recycling to occur. In this presentation a common plastic, polyethylene terephthalate, i.e., PET or plastic #1, has been studied because it is recycled at relatively high rates in the U.S. as compared to other plastics. A material flow analysis is described for PET resin showing materials collected, reclaimed for flake, and converted into items with recycled content. Imports/exports, reclaimer residue, and disposal with mismanaged waste are all shown for U.S. flows of PET. Barriers to recycling PET exist in the collecting, sorting, reclaiming, and converting steps, and this presentation describes some of them. This effort also models sorting at material recovery facilities (MRF) and reclaimers, with detailed descriptions of the material streams involved, to characterize the resource use and emissions from these operations that are key processes in the recycling system. Example results include greenhouse gas intensities of 8.58 kg CO2 equivalents per ton of MRF feed and 103.7 kg CO2 equivalents per ton of reclaimer PET bale feed. The results can be used in system analyses for various scenarios and as inputs in economic input-output and life cycle assessments.