Life Cycle Assessment of Polypropylene from WEEE: Utilizing the Circular Footprint Formula for Environmental Evaluation

The urban stock of waste electrical and electronic equipment plastics (WEEEP) is significantly rising. However, less than 8% is recycled, while recyclates make up only about 3% of plastics applied in new electrical and electronic equipment. Life Cycle Assessments (LCA) can quantify the environmental implications inextricably linked with both primary and secondary production of plastics. LCA scholars, however, widely acknowledge that modelling recycling in LCA presents significant methodological challenges that can affect accuracy and comparability of results. Particularly, the inherent dual purpose of recycling - treatment of waste and production of secondary raw materials - creates ambiguity for allocation of environmental burdens and credits. The Circular Footprint Formula (CFF) aims to standardize allocation of impacts throughout the lifecycle. The formula is based on 19 parameters which require extensive data and is criticized for its complexity. This study investigates these two aspects: (1) The environmental impacts from cradle to gate associated with the production of high-quality recycled polypropylene (rPP) sourced from post-consumer WEEEP compared to primary PP is assessed, based on extensive primary and secondary data. (2) The CFF is applied to the rPP case, and 19 parameters are evaluated for 5 scenarios. The LCA results show a savings potential of 45% for rPP compared to primary PP for Global Warming Potential, and '100% for fossil resource use as well as further benefits for several environmental impact categories including Ozone Depletion, Human Toxicity and Acidification. Environmental impacts assessed with the CFF highlight the savings potential of increased collection, recycling rate, recycate quality and recycling yield. However, a significant uncertainty of CFF results remains due to the absence of reliable data. This renders CFF calculations prone to imprecision and misinterpretation.