Influence of end-of-life allocation, credits and other methodological issues in LCA of compounds: An in-company circular economy case study on packaging

摘要

The aim of this article is to present a circular economy case study and investigate and discuss effects of end-of-life (EoL) allocation and crediting strategies on the results of this case study. In the case study, replacement of eucalyptus wood sheets, which are used to separate loaded pallets to prevent damaging each other during top storage in the company, by plastic compound alternatives composed of virgin PP, recycled PP and mineral fillers, is studied. When their life time is over, plastic compound sheets are sent to be recycled in the recycling facilities of the company. While performing this comparative LCA, a methodological discussion on how to credit the system in open-loop (OL) and close-loop (CL) recycling is performed. The use of Q factors (quality factors), instead of 1:1 substitution of virgin materials by recycled ones, is recommended and how to define these Q factors is discussed. The use of Q factors based on the mechanical properties of virgin and recycled materials, which is flexural modulus in this case, is recommended. Finally, a formula for the calculation of the Q factor of the compound material leaving the CL recycling after several recycling cycles, is proposed. Results show that, for this case study, plastic compound sheets are environmentally better alternative than eucalyptus wood sheets for most of the environmental impact categories evaluated due to the following reasons: higher number of uses, lower weight, use of recycled PP and mineral fillers, and longer lifetime. However, in two impact categories (resource depletion water and resource depletion mineral, fossils and renewables) eucalyptus wood sheets are found to have slightly better results. For the rest of the impact categories, the difference in the results are so high that different crediting methods do not affect the results in this case; however, they may in others. Among the scenarios evaluated OL recycling with market mix substitution is found to provide the highest impacts. (C) 2018 Elsevier Ltd. All rights reserved.