Planning of three-level facilities network for collection and recycling of E-waste: A MILP-based modelling approach

Abstract

The collection and recycling of E-waste are vital for the economy, the environment, and public health. From a financial perspective, planning the necessary E-waste facilities, including the collection centres and recycling centres, can be a challenging and laborious undertaking. The E-waste recycling facilities network planning problem involves three types of facilities related to different stages. Firstly, E-waste generated from households is collected at a location known as a collection point, from where it is transported to collection centres where it is sorted into several product groups, and lastly, it is sent to relevant recycling facilities. The recovered materials in recycling facilities are then forwarded to original manufacturers for reuse, while hazardous waste is dumped in landfills. The capacity and location decisions of recycling facilities are strategic and important as it involves huge capital investment, and they should be far from residential areas. Furthermore, to reduce transportation costs, these facilities should be located nearby collection centres and landfills. So, to reduce the overall E-waste recycling cost, the decision regarding the number and location of all three facilities plays an important role.In this study, the planning problem of determining the optimal number and location of collection points, collection centres, and recycling centres, as well as the flow of E-waste to these facilities, has been tackled by proposing a mixed-integer linear programming (MILP) formulation. The objective is to minimise the overall cost associated with these operations. The costs include the transportation cost and the cost of establishing all types of E-waste facilities. The application of the model has been demonstrated using a numerical example. The numerical case has been solved using GUROBI 8.0.1 optimisation solver. This study provides a framework to plan an effective and efficient network of E-waste facilities at minimum cost and lesser environmental impact.