Towards an environmentally sound metric to evaluate post-consumer plastic packaging waste recycling

Abstract

In the recent years, the circular economy (CE) has emerged as an alternative to current linear economic models with prospects of achieving the decoupling of environmental impacts from economic growth. To this end, CE models focus on the permanence of products, materials, and value in the economy, eliminating as much waste as possible. In waste management policy making, traditional indicators, such as recycling rates, are still the norm as demonstrated by the latest binding goals for plastic packaging recycling set by the EU in the Packaging Waste or the Single Use Plastics Directives. However, these have been criticized for overlooking qualitative aspects that are fundamental in the CE. Consequently, several indicators have been proposed as an alternative to monitor this new economic paradigm. Among these are value-based metrics. Economic value contains information about both the quality and the quantity of the specific material or product. In addition, value can be altered using economic instruments, such as taxes, to align value with other relevant environmental or social interests.
The validity of using value-based metrics to evaluate the performance of waste management systems was analysed. Several scenarios for possible configurations of the Dutch post-consumer plastic packaging waste (PCPPW) management network were defined and assessed in terms of technical, economic, and environmental performance. Two technical metrics, intermediate recycling rates (iRR) and recycling rates (RR), and one value-based metric, the circular economy index (CEI), were compared to the environmental and economic performance of the scenarios. The CEI showed a better alignment with all the environmental impact categories than the mass-based metrics. Most importantly, the value-based metric proved capable of capturing the significance of the quality of the recycled plastics in the displacement of primary raw materials, thus fostering high quality recycling over downcycling. However, no correlation was found between the economic performance and the presented indicators. There are multiple business models that achieve good economic performances with diverse environmental, technical, or value-recovery performances. This suggests that current policies are unable to successfully align economic and environmental strategies. More research should be put in defining holistic policies that promote environmental and economically sustainable practices.