A multi-objective mathematical model for the operations planning of a reverse logistics facility and an application

In today's world, the materials that are recycled or remanufactured, especially electronic waste, provide a solution for declining natural resources. Because of the rapid increase in consumption in the developing countries, searching for new naturel sources or reusing the existing resources is gaining importance and become one of the trend topics. Reverse logistics activities are inevitable for companies that want to prevent environmental pollution due to harmful wastes and to obtain economic advantages by evaluating these wastes. Regulations that are implemented in many developed countries and soon to be implemented in Turkey, will also make reverse logistic activities compulsory. Due to the ambiguous parameters involved, in the reverse logistics chain, which has a rather complex structure than a conventional supply chain, obtaining positive results is quite difficult. Reverse logistics, includes all operations related to the collection, assessment, recovery and disposal of these wastes in an appropriate way. Many studies have been carried out to optimize collection and transportation costs, which are considered the most important expense items in logistics. In this thesis, refrigerators are examined in particular, composition and recyclability rates of them evaluated to calculate the financial gain and disposal costs of hazardous parts. While the dangerous refrigerants used in the refrigerators are banned all over the world, there are still refrigerators in the market that contain these and other dangerous gases and liquids. Authorized special firms provide firms suitable disposal of these hazardous materials generally for money. This is also burden for reverse logistics companies. In this study, a multi-objective, multi-product and multi-period MILP mathematical model for a reverse logistics firm was proposed. Under various constraints, whether to collect products from the specified regions, determining the required source amounts and inventory decisions were discussed. In addition, Sensitivity analysis was conducted with various scrap prices to have better understanding.