1987

Kaila, Juha

A mathematical model for strategy evaluation of municipal solid waste management systems has been developed.The basic objective in model development has been to create a tool for practical strategy evaluation applications.The model is more compre hensive than earlier models in taking into account all the functional elements of a waste management system.Thus a wider range of technical alternatives and possible policy decisions and their effects can be analysed.In addition to the general model formulation, costs and performance of functional elements are presented.These include onsite storage of waste, waste collection and transport in collection vehicles, intermediate waste handling, transport between sites and processes, garages, and final disposal. The basic structure of the model is, how ever, flexible in being independent of the detailed cost and performance functions of functional elements.Many different types of cost functions can be used without a need to change the solution algorithm.The solution algorithm is heuristic.For solution search the system has been divided into two interconnected subsysterns.These are the collection and transport system and the processing and disposal system.The solution search is done iteratively by seeking a solution for both subsystems in sequence until the solutions are consistent.The solution algorithm has been tested with data from four different applications and the results have been compared with the best results obtained with other models used in these applications.The algorithm gave good results in all tests.The best result obtained in each example was probably the optimum solution or very close to it.The algorithm is also fast in finding solutions for large problems because the number of iterations in solution search is almost independent of the size of the problem.The model has been applied several times during actual planning processes.In all these cases the use of the model has produced necessary information for further development of plans.One of the cases is described as an example of how the model can be used in practice.