Fuzzy Simulation-Optimization Model for Waste Load Allocation

Document Type : Research Paper


1 Grad. Student of Environmental Engineering, Iran University of Science and Technology

2 Professor, Faculty of Civil Engineering, Iran University of Science and Technology

3 Ph.D, Student of Water Resources Management, Iran University of Science and Technology


This paper present simulation-optimization models for waste load allocation from multiple point sources which include uncertainty due to vagueness of the parameters and goals. This model employs fuzzy sets with appropriate membership functions to deal with uncertainties due to vagueness. The fuzzy waste load allocation model (FWLAM) incorporate QUAL2E as a water quality simulation model and Genetic Algorithm (GA) as an optimization tool to find the optimal combination of the fraction removal level to the dischargers and pollution control agency (PCA). Penalty functions are employed to control the violations in the system.  The results demonstrate that the goal of PCA to achieve the best water quality and the goal of the dischargers to use the full assimilative capacity of the river have not been satisfied completely and a compromise solution between these goals is provided. This fuzzy optimization model with genetic algorithm has been used for a hypothetical problem. Results demonstrate a very suitable convergence of proposed optimization algorithm to the global optima.


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