Abstract for: Exploring the Effect of Uncertainty and Dynamics in Material Flows in the Circular WEEE Supply Chain

Waste Electrical and Electronic Equipment (WEEE) contains numerous critical and scarce materials that have significant environmental impacts if not properly recovered. Uncertainty in WEEE flows, due to informal flows, product retention, and variations in material composition, undermines the effectiveness of recycling, preventing targets from being met. Dynamic interactions further compound the sources of uncertainty. To address these challenges, this study proposes a novel stochastic system dynamics model that integrates system dynamics with uncertainty to capture informal flows, WEEE material compositions, and product lifetimes. The methods used include indirect estimation techniques, Hierarchical Weibull, and Bayesian hierarchical Dirichlet distributions. By embedding stochasticity directly into the feedback structure, the model aims to capture how the system handles multiple sources of uncertainty at the same time, and how this affects policy outcomes.