Optimal Facility Locating for Wide-Area Municipal Solid Waste Treatment: A Case Study of Kyoto Prefecture in 2050

Abstract

In this study, we formulated the facility siting plan as a mixed integer programming problem for Kyoto Prefecture in the year 2050, and obtained an approximate solution for the optimal siting. In particular, we focused on the trade-off between economies of scale due to the expansion of the scale of treatment relocation and disadvantages due to longer transportation distances, and performed sensitivity analysis when the unit cost of transportation was varied. Compared to the current 16 facilities, the optimal arrangement resulted in 3 to 6 treatment facilities, and treatment costs were reduced by 15 to 20%. Higher unit transportation costs led to greater consolidation, while lower unit transportation costs tended to lead to decentralization. Under the condition of high unit transportation cost, treatment cost tended to increase as the minimum size of treatment facilities was increased.