A reverse logistics network for recycling in Chile: a case in Concepción Sergio Aliaga, Lorena Pradenas and Carlos Contreras-Bolton Departamento de Ingeniería Industrial Universidad de Concepción Concepción 4070409, Chile saliaga@udec.cl, lpradena@udec.cl, carlos.contreras.b@udec.cl Abstract Currently, pollution and poor recycling are global issues. Recycling is a widely used waste-management method throughout the world and contributes to eliminating waste efficiently and reduces the excessive use of natural resources. In this study, an optimized collection system of household recyclable material has been characterized and designed for cities with a low recycling level. To address this task, we propose a mathematical programming model that integrates two decisions, allocation and routing of different varieties of recycled products. First, the distance traveled by each customer and the costs associated with installing smaller collection centers are minimized. Subsequently, to minimize recyclable material transport, a route planning problem is solved by collecting from centers of greater capacity rather than from small centers, according to the traveling salesman problem. To illustrate our approach's usefulness, a numerical example based on the case of Chile's southern city is considered. The results suggest that the developed model is a practical tool for decision-makers in making tactical and operational decisions to reduce recycling costs. Keywords: Recycling logistics, Supply Route optimization. 1. Introduction Currently, pollution and poor recycling are global issues. Given the ease of communications and competition between companies, it has become essential to add value to proposed implementations to compete in the market. Despite the development and diffusion of new technologies occurring at accelerated rates, this is not reflected in the development of appropriate technologies or policies that manage all waste, especially electronic waste generated in developing countries. This issue causes problems in material handling and contamination as well as a greater environmental uncertainty regarding the “end” of many products (Tansel, 2017). Several authors consider recycling as part of the chain, that is, what takes place after the product is no longer used by the consumer, when it reaches the garbage and finally, a landfill, as a growing problem in current societies. Every day, more products are consumed and discarded at an accelerated rate (Johnsen et al., 2014). The global trend with respect to waste generation is shown in Table 1 and currently, the world is generating 2.01 billion tonnes of municipal solid waste annually. Worldwide, waste generated per person per day averages 0.74 kilograms varying from 0.11 to 4.54 kilograms. The amount of global waste is estimated to reach 3.40 billion tonnes by 2050 (Kaza et al., 2018). Recycling is based on obtaining raw material or products from a waste and it can be total or partial, depending on each case. From some materials, it is possible to obtain the raw material to be used differently, whereas others require directly generating a new product. An example of an already used good is a plastic bottle. This bottle can go to the garbage or be recycled and thus acquire a new life cycle. Therefore, recycling contributes to eliminating waste efficiently and reduces the excessive use of natural resources. This process of the reuse of products and materials is known as reverse logistics (Agrawal et al., 2015; Govindan and Soleimani, 2017). The most commonly recycled products are as follows: paper and cardboard, plastics in their multiple varieties and electric/electronic articles. Each of these wastes presents their own complexities of handling and treatment. Generally, recycling involves sorting operations that separate recoverable waste from the others and recycling plants where the wastes are finally recycled and/or stored (Edalatpour et al., 2018; Gold and Seuring, 2011; Heidari et al., Proceedings of the International Conference on Industrial Engineering and Operations Management Sao Paulo, Brazil, April 5 - 8, 2021 © IEOM Society International 2760