Optimal scheduling of consecutive landfill operations with recycling

A mathematical mode is presented to determine the optimal operation of consecutive landfills while incorporating recycling programs. The model is capable of handling currently available landfills as well as numerous proposed future landfills. Model sensitivity analysis is performed by varying the capacities of present and future landfills, in addition to conventional objective function sensitivity analysis and right-hand-side sensitivity. In addition, the model incorporates the possible utilization of recycling programs. The model is driven by overall long-term costs of operation. The optimization model indicates landfill use characteristics throughout the planning horizon, including the times at which landfills are closed and opened and the amount of waste that is diverted to recycling. Model solutions also indicates that recycling options may be implemented even though recycling costs exceed the cost of the current disposal option, in order to extend the lifespan of less expensive landfills and to defer more expensive future landfills.