Plastic recycling in a circular economy; determining environmental performance through an LCA matrix model approach.

To ensure a circular economy for plastics, insights in the environmental impacts of recycling and optimal recycling choices for specific plastic polymers are crucial. This was obtained by determining the environmental performance of 10 selected recycling technologies with varying TRL levels, using the chemical properties of the top 25 produced polymers in Europe. The results were collected in a life cycle assessment (LCA) 'matrix' model. To simulate realistic plastic recycling challenges, case studies of PE/PP foils from municipal waste and ABS plastic with brominated flame retardants were developed, to be used as an addition to the LCA matrix model results. Potential emission reduction was assessed by combining LCA matrix outcomes with European polymer demand data. The LCA matrix model illustrates that potential environmental performance of recycling technologies varied strongly per polymer type and did not always follow the state-of-the-art recycling hierarchy. Commodity plastics performed well with tertiary recycling technologies, such as gasification and pyrolysis to monomers; secondary mechanical recycling was outperformed. A focus on primary recycling is environmentally beneficial for most engineering and high performance plastics. To enhance the performance of primary recycling technologies, a higher purity and improved sorting is required. As demonstrated in the case studies, low sorting efficiencies due to impurities reduces positive environmental impacts. Hence, optimal environmental performance of recycling is obtained where pre-treatment (sorting, cleaning) is adapted to the recycling technology. According to the model, recycling the 15 most demanded polymers in Europe reduces CO2 emissions from plastics by 73% or 200 Mtonne CO2 eq.

Sources, transport, and accumulation of different types of plastic litter in aquatic environments: A review study.

Types of plastic waste in different aquatic environments were assessed to obtain a global framework of plastic waste transport and accumulation, relevant for plastic pollution mitigation strategies in aquatic environments. Packaging and consumer products were the most encountered product categories in rivers, while fishery items dominated in the oceanic environment. Plastics from electronics, building and construction, and transport were barely observed. For polymers, polyethylene and polypropylene contributed most to pollution in all environments. The highest diversity in polymer composition was found in oceanic and freshwater sediments. It is therefore argued that a large fraction of plastic waste accumulates here. This confirms that plastic waste transport and accumulation patterns were most affected by the density, surface area, and size of plastics. Only thick-walled, larger plastic debris from low-density polymers are transported through currents from rivers to ocean, while the larger fraction of plastic litter is likely retained in sediments or beaches.