Optimizing Sustainable PET Plastic Supply Chain Model with Reverse Logistics Waste Tracking System

The world’s extensive production and consumption of single-use polyethylene terephthalate (PET) plastics contribute to land pollution, resource depletion, and greenhouse gas emissions (GHG). These problems are primarily driven by the high use of fossil fuels, excessive energy consumption, and improper disposal practices. Addressing these challenges necessitates the adoption of sustainable alternatives within the PET plastic supply chain (SC). This study develops a sustainable SC model between a PET bottle manufacturer and a zoological park retailer, incorporating reverse logistics and emission reduction. The model implements a deposit refund system (DRS) to encourage customers to return used bottles and a waste tracking system (WTS) to achieve 100% recovery of unreturned bottles. Additionally, the model incorporates green technology to reduce emissions and carbon cap-and-trade (CAT) to cap pollution and promote cleaner production. The expected integrated profit per unit of time is maximized with optimal cycle time, green technology investment, and waste tracking investment. The concavity of the integrated profit is demonstrated using the Hessian matrix method. The numerical examples, comparative analysis, sensitivity analysis, and managerial insights are presented to validate the model, explore the impact of sustainable practices, and derive practical implications. The results demonstrated that implementing green technology increased profit by 1.73% and implementing WTS increased profit by 1.26% while also reducing emissions. The implementation of DRS resulted in a 14.58% increase in profit. The study shows that integrating DRS, WTS, green technology, and carbon CAT in the PET supply chain reduces environmental impact while improving profitability, offering valuable guidance for sustainable policy and managerial decisions.