A robust optimization method for integrating on-site medical waste treatment in rural areas with centralized treatment in urban areas

Rural healthcare facilities generate medical waste (MW) and current practice routes this waste to centralized treatment plants in urban areas. Advances in on-site equipment have made local treatment of rural MW feasible, but no systematic framework exists for coordinating on-site and centralized treatment in an integrated urban-rural system. This study is the first to formulate on-site treatment as a mode-choice decision jointly optimized with centralized treatment across urban and rural areas under transportation cost uncertainty. A multi-objective robust optimization model is developed to minimize cost, risk, and carbon emissions, evaluating three centralized technologies and two on-site treatment options. Results show that on-site treatment reduces system risk and carbon emissions. The robust model yields more conservative cost estimates than its deterministic counterpart while achieving lower risk and emissions by retaining more on-site treatment selections. Combining centralized and on-site treatment withstands larger surges in MW generation than centralized treatment alone, offering resilience for public health emergencies. Incineration is the most cost-effective centralized technology despite the highest emissions, while microwave sterilization is the cheapest on-site option and high-temperature steam sterilization yields the lowest emissions. This study offers a practical decision-making tool for the integrated management of urban-rural MW systems with centralized and on-site treatment under uncertainty.