Location And Optimization Of Municipal Waste Collection And Disposal Facilities Considering Uncertainty And Outsourcing

With increasing amount of waste, waste collection and disposal process bring sizable cost to both government and residents. Also, waste colleting facilities would do disservice to nearby resident. So layout of waste-collecting and waste-disposing facilities is a topic with practical meaning.This thesis studied the location of municipal wastes collection and disposal facilities in a three-echelon network, which consists of collection units, transfer stations and terminal facilities. Two bi-objective models were built separately to solve problems under the hypotheses with and without waste separation, both pursuing logistics cost minimization and disservice minimization. Furthermore, robust optimization models were developed considering uncertainty and outsourcing.As oil price perturbation, traffic jam, and vehicle problem make it difficult to precisely estimate the unit cost of waste transportation, this thesis employed an interval-based robust optimization method to develop robust optimization model considering cost uncertainty. The cost is assumed to be perturb within a closed interval, following an unknown while symmetric distribution. The study was conducted under both not separating and separating waste hypotheses.Also, the amount of waste produced by residents varies with season alternation, government policy change, and the public awareness degree of environment problem. These perturbations may make the solution achieved by determined model less attractive, even infeasible. Thus, three scenarios were considered to represent possible realization of actual waste amount. In the meantime, two different recourse actions-transfer station outsourcing and resident area outsourcing-were studied and analyzed. All the mathematical models were mixed-integer linear programming problems, and they were solved by LINGO11.0.