Optimal strategy to sort plastic waste considering economic feasibility to increase recycling efficiency

In this study, we suggested an optimal strategy to sort plastic waste to improve recycling efficiency considering economic feasibility. To derive the optimal sorting strategy, we developed a novel optimization model that considers the overall cost, which is sorting cost minus the revenue obtained by selling the recycling plastic from the sorting cost. Then we used the developed model to identify the optimal strategy to sort plastic waste in mixed-integer programming that minimizes the overall cost of plastic waste sorting systems. We also conducted a sensitivity analysis to analyze the extent to which the results obtained can change under different conditions. The optimization results, identify that the plastics in the optimal sorting strategy are of four types: LDPE, HDPE, PP, and PVC. This optimal sorting strategy increase the overall sorting efficiency slightly by 4 wt%, but considering the revenue obtained by selling the recycled plastic the strategy significantly decreased the overall sorting cost by 69.28 % compared to the conventional case. The developed model can determine the optimal strategy to sort plastic waste considering economic improvement. Therefore, the results allow increase in plastic recycling by minimizing the overall cost of the sorting system.