In this paper, we discuss a case study regarding transfer stations siting in a Solid Waste Management System, building a multi-criteria model potentially adequate to the involvement of multiple actors. A Decision Support System (DSS), named SABILOC ([1]), integrating an Interactive Bi-objective Integer Programming Module and a Multi-attribute Module is used. The last module allows an a posteriori more detailed analysis of the solutions selected during the first module. Furthermore, the DSS includes meaningful graphical tools and integrates a Geographic Information System (GIS).