Economic and Environmental Analysis a National-Scale, Thermo-Chemical Plastic Upcycling Infrastructure in the United States

Global rates of plastic production demand comprehensive and reliable plastic waste management systems to avoid the worst impacts of terrestrial and marine plastic pollution. However, overall plastic recycling rates remain insufficient, while the bulk of plastic wastes are incinerated, landfilled, or allowed to accumulate in the biosphere.

Traditional plastic recycling by mechanical methods is a mature technology but faces significant inadequacies as a plastic management strategy given that it has been developed only to accept limited types of plastics. This limitation reinforces the parallel need for environmentally damaging disposal methods, such as landfilling and incineration, to accept waste products not fit for mechanical recycling.

A complementary strategy for plastic waste management, known as plastic “upcycling,” uses chemical methods rather than mechanical ones. Upcycling involves a chain of processing technologies: beginning with the sorting and purification of plastic fractions of common recyclable waste streams at municipal recovery facilities (MRFs) and plastic reprocessing facilities (PRFs), plastic wastes undergo a series of chemical conversions including pyrolysis and steam cracking to arrive at pure plastic monomers, which can finally be repolymerized into products (here, low-density polyethylene and polypropylene, or LDPE and PP) with the same properties as virgin plastics.

To date, plastic upcycling has not received sufficient analysis exploring how an upcycling circular economy may be realized. Our study will use a framework to examine the potential for an upcycling system to be instituted at a large scale (the continental US), allowing us to design an upcycling network of facilities that reaches all residential waste producing sources in the continental US. We determine that upcycling provides a vastly more favorable economic picture than current downcycling, in which the value of polymer end-products propagates through the value chain and even provides an opportunity for residential waste producers to be paid for their recycled plastic, and quantify its economic sensitivity to a number of key parameters. Finally, we comment on the potentially favorable environmental performance of upcycling relative to current US plastic disposal methods.