Seminar series – Dr Ana Torres

The current extract-make-use-dispose paradigm throughout product supply chains has enormous environmental and socioeconomic impacts, including climate change, biodiversity loss, depletion of natural resources, and pollution. Policymakers and industry practitioners have suggested the Circular Economy (CE) to solve these challenges. CE aims to re-design current processing/ consumption practices to eliminate waste and pollution, circulate products and materials at their highest value, and regenerate nature. Although conceptually simple, the development of CE networks is hindered by the lack of scientific guidance on how to implement and evaluate the effectiveness of CE initiatives.

This talk will present the results of recent projects related to the advancement of our understanding of CE networks. During the first part of the talk, I will discuss a generalized superstructure-based optimization framework for designing and optimizing circular economy (CE) networks under multi-criteria decision-making. We apply the proposed framework to a case study of the polyethylene terephthalate (PET) supply chain, considering various waste valorization pathways.

In the second part of the talk, I will present the advances on the dynamic modeling of CE networks.  Dynamic modeling is needed as some CE initiatives, such as product reuse, evolve over time, so steady-state models are unsuitable.  We start by proposing a dynamic model for a generalized actor, then derive specific models for five actors (a manufacturer, consumer, material recovery facility (MRF), recycling facility, and the Earth), and combine them to form a prototypical circular SC network. We apply this framework to the supply chain for plastic packaging to assess the effects of slowdown-the-loop initiatives, such as product reuse, and close-the-loop initiatives, such as increased recycling.