MO.3.C || Circularity and Life Cycle Aspects of Recycling Technologies

Schwarz, Anna; Ligthart, Tom; van Harmelen, Toon

In a circular economy, recycling of plastics is required to reduce pressure and negative impacts on the environment. To enable this, optimal recycling choices for plastic products from an environmental perspective has to be determined. Life Cycle Assessment (LCA) was used to determine and compare the environmental performance of ten different recycling technologies with varying technology readiness levels (TRLs). This was executed using the ecoinvent database in combination with state-of the-art recycling data and the chemical properties of the top 25 produced polymers in Europe. The results were collected in an LCA ‘matrix’ model. On top of this theoretical model, case studies were developed, to demonstrate the applicability of the LCA matrix model to state-of-the-art plastic recycling challenges. The first case study included PE/PP foils from municipal waste and the second ABS plastic with brominated flame retardants. The LCA matrix model illustrated that potential environmental performance of recycling technologies varied strongly per polymer type and did not always follow the determined recycling hierarchy. Commodity plastics performed well with tertiary recycling technologies, such as gasification and pyrolysis to monomers; secondary mechanical recycling was environmentally outperformed. Focusing on material preservation through primary recycling is environmentally beneficial for most engineering and high performance plastics. To enhance the performance of primary recycling technologies, a higher purity of plastic waste is required, to be obtained through improved sorting or using low TRL technologies such as dissolution. As demonstrated in the case studies, low sorting efficiencies increase the environmental impacts, as significant quantities are lost for recycling and incinerated. Hence, optimal environmental performance of recycling is obtained where pre-treatment is adapted to waste stream polymer types and their optimal recycling technology.