A system dynamics model proposal to determine the impact of industrial solid waste recycling on environmental and economic performance

The pressure to be sustainable and the increasing awareness of sustainable development have led enterprises to redesign traditional supply chains that focus more on profitability and cost. With the goal of creating a sustainable supply chain of enterprises, the need to evaluate their waste as a resource has become more important. It has been observed in the literature that there is no comprehensive theory for recycling of solid wastes with manufacturer responsibility and as a result of pursuing the impact on the supply chain performance. In this thesis, it is aimed to propose a model that reveals the effects of industrial waste recycling on the sustainable supply chain performance. It is also aimed to determine and compare the effects of plastic, glass, steel and aluminum recycling on sustainable supply chain performance. In the second part of the study; it is aimed to examine the results to be achieved by the implementation of similar ones in our country based on the recycling incentive systems implemented in many countries for sustainable development goals. In this scenario, it is also aimed to evaluate the effects of the recycling incentive system separately on plastic, glass, steel and aluminum material wastes, and to decide on the product groups that contribute the most. The system dynamics approach was used in the thesis due to the need to model the complexity inherent in the recycling system, analyze the relationships between variables, and evaluate different scenarios. The data in the study were obtained from both the experts in the sector and the literature. Primary data was obtained by interviewing experts from 16 recycling companies from six different cities. In addition, for the weights of the sustainability criteria needed in the model, a multi-method approach was preferred by using the Best Worst Method. At this stage, the application was carried out with 10 experts from each product group and a total of 40 decision makers. When the study findings are evaluated for two years, the contribution of plastic recycling on sustainability performance has reached 39%, glass recycling 31%, steel recycling 44% and aluminum recycling 47%. In terms of water consumption, the biggest contribution rate of recycling is in the glass product group, while its least contribution rate is in the plastic product group. In terms of energy consumption and greenhouse gas emission, the largest contribution rate of recycling is in the aluminum product group, while its least contribution rate is in the glass product group. In terms of economic sustainability, steel recycling gave the highest contribution rate on both the profitability, which includes the opportunity cost, and the total cost. In the case of the implementation of waste incentive systems, the results vary for different purposes and therefore the scenario outputs are evaluated in multiple stages. However, it is seen as a better option for policy makers to prioritize aluminum recycling due to the higher benefits it will provide to both environmental and economic sustainability performance in many ways.