Heuristic and simulation techniques for the scheduling of hazardous waste processing in an integrated treatment facility

The basic strategies for optimizing processing schedules of hazardous waste in an integrated hazardous waste treatment facility are analyzed. Five schedule optimization heuristics were evaluated on six simulation models of hypothetical integrated hazardous waste treatment facilities. The six models represented combinations of one of three unit process configurations and one of two facility operating policies. The heuristics were evaluated with respect to their ability to minimize the average completion time (makespan) of a specified set of jobs. The same five heuristics were applied to a model representing the physical and chemical treatment plant of the Alberta Special Waste Management Corporation. Operation under two operating policies for this case study was evaluated, and the results were compared with the hypothetical model results. Some heuristics were found to be capable of reducing makespans by 13–14% relative to the first in, first out heuristic. Key words: hazardous waste treatment, scheduling, heuristics, simulation modelling.