Hazardous Waste Removal : A transportation/Transshipment Problem


Click here for spreadsheet

Tab "Unrestricted" Cost = $75,000
1000 tons of hazardous wase need to be removed from Hate Canal, and 1500 tons need to be removed from 4 Mile island. 
The waste is removed from the site by truck. 
The trucks can carry the material directly to one of the two disposal sites Yucky Mountain or NIMBY,
or to one of three transshipment sites (Dirty Depot, Smelly Station, or Junk Junction) to be loaded on trains to the disposal sites. 

Tab "Route"  Cost =  $83,500
The "Channel Capacity" matrix shows the maximum amount of hazardous waste that is permitted to travel over each transportation link.
The route capacity constraints are "simple upper bounds" so their shadow proces show up in the sensitivity report as reduced costs.  If we could increase capacity of a route whose capacity is binding, this would redice out total cost..

Tab "Node" Cost =  $80,000
The "Max to" column shows the maximum amount of waste that can be accepted temporarily at each transshipment point and the amount of waste that can be accepted permanently at each disposal site.

Tab "Route and Node"  Cost =  $89,750
This spreadsheet applies both the channel and the node constraints, hence the higher (but more realistic) total cost.

Tab "Warehouse Location"  Cost =  $114,500
Now we can only use two of the three trans shipment points.  We need to decide which two using "mixed integer linear programming."