A mathematical model for the municipal solid waste location-routing problem with intermediate transfer stations

© 2015 Asefi, Lim and Maghrebi. Municipal solid waste management is one of the challenging issues in mega cities due to various interrelated factors such as operational costs and environmental concerns. Cost, as one of the most significant constraints of municipal solid waste management can be effectively economized by efficient planning approaches. Considering diverse waste types in an integrated municipal solid waste system, a mathematical model of the location-routing problem is formulated and solved in this study in order to minimize the total cost of transportation and facility establishment. The main aim of the proposed model is to optimize the locations of the waste management system's facilities including transfer stations, treatment centres, recycling centres and disposal centres, and identify the optimal routes to and from the facilities. A case study of the location-routing problem in New South Wales, Australia, is investigated and analysed. Twenty five districts are selected to represent the whole state of New South Wales for the analysis. Twenty-four districts are also assumed to be candidate locations for each of the six types of the system's facilities which leads to a network with 24*6 potential location nodes i.e. 24^6 possible solutions. The presented application in this study is by far the largest size of the network among the related studies in the literature