(84ap) Economic and Environmental Assessment of Plastic Sorting and Recycling: A Multi-Period Approach

Plastic recycling rate reveal low rates compared to production, disposal, incineration rate, largely due to the inadequacy of effective sorting processes [1]. Consequently, plastics are often disposed of through incineration and landfilling, leading to increased greenhouse gas emissions and environmental pollution. Despite several studies that have mathematically approached plastic sorting processes and integrated them with recycling processes for economic and environmental impact comparisons, research applying multi-periods remains scarce.[2]

This study aims to develop an integrated model that considers the growing amount of waste plastic affected by multi-periods and optimizes the benefits of the sorting and recycling processes. A mixed-integer linear programming problem is employed to solve the selection combinations of sorting order and recycling processes for each type of plastic, such as material recycling through pelletization for PET, pyrolysis oil through pyrolysis for LDPE and HDPE, and energy recovery through incineration for other synthetic resins[3]. By combining the sorting process with recycling processes based on sorting order, the study conducts a comparative analysis through several case studies to identify the optimal benefits.

Economic evaluations reveal that when the amount of plastic waste to be processed is minimal, the number of sorting machines has the most significant impact on the objective function. However, as the amount of waste increases, the recycling rate becomes more influential than the number of machines. Environmental evaluations indicate that higher recycling rates result in increased CO2 emissions due to greater electricity consumption from the operation of more machines and longer operation times. To address the trade-off between economic and environmental factors, the study selects the optimal model through case studies.

Literature cited:

[1] Geyer, Roland, Jenna R. Jambeck, and Kara Lavender Law. "Production, use, and fate of all plastics ever made." Science advances 3.7 (2017): e1700782.

[2] Lee, Jaewon, et al. "Multiobjective Optimization of Plastic Waste Sorting and Recycling Processes Considering Economic Profit and CO2 Emissions Using Nondominated Sorting Genetic Algorithm II." ACS Sustainable Chemistry & Engineering 10.40 (2022): 13325-13334.

[3] Basuhi, R., et al. "Environmental and economic implications of US postconsumer plastic waste management." Resources, Conservation and Recycling 167 (2021): 105391.