2.1. A MIP model for the strategic planning of a SWM system
The possible configurations of a SWM system to be designed at
the strategic level can be represented by a directed graph G ¼ ðV; AÞ in which the vertex set V may be partitioned into four subsets:
VO representing sources, VS modeling potential transfer stations,
VP describing processing facilities (incinerators, waste-to-energy
plants, etc.), and VL representing landfills, disposal facilities and
markets for recycled products and energy. Arcs in set A correspond
to feasible shipments between sites (Fig. 1).