A Proposition for an Expanded Modelling Approach for Dealing with Multifunctional Waste Output Systems in Life Cycle Assessment: Bridging the Gap Between Circular Economic Product Design Strategies and Societal Goals

Reduce, reuse, recycling, and energy-recovery are core strategies proposed for moving towards a circular economy. Therefore, it is important to evaluate if and how these strategies contribute to the circular economy. Life cycle assessment (LCA) is often proposed for evaluating the environmental performance of resource and environmental mitigation strategies from a product perspective to inform value chain actors and societal policy makers. However, there are disagreements in LCA on how to distribute the environmental burdens and potential benefits of recycling, reuse, and energy-recovery between the products that provide or use secondary material flows. Additionally, it is disputed how well the product perspective informs societal decisions. This dispute has led to many suggested modelling approaches, which often lead to different results for the same reuse, recycling, and energy recovery scenarios. This thesis studies the consequences of different end-of-life modelling approaches for understanding the environmental implications of recycling and reuse. An expanded LCA modelling approach is proposed for environmentally evaluating reuse and recycling aimed at bridging its current informational gap for informing both value chain actors and societal decision makers.