Optimal Waste Load Model in Karoon River with the Pollution Loading Loss Analysis

The optimal managment of pollutants discharged into the rivers plays a critical role in improving water quality. In this paper, a new method is developed for Cost-based waste-load allocation (C-WLA) modeling with trade-off between the cost of treatment at loading points and the loss of pollution at the points of withdrawal from the river system. For this purpose, the qualitative simulation model (MIKE11) is coupled with Particle Swarm Optimization (PSO) algorithm. The model is applied to the Karoon River system. At the first step, the sum of treatment cost and loading damage of TDS pollutant was estimated in the river system. Then, with insights into the impacts of the trade-off policy between treatment cost of dischargers and pollutant load loss, optimal treatment percentages and optimal concentration threshold limit were determined in a monthly base and for one year. The results demonstrated that the C-WLA model has the good efficiency in managing the TDS pollutant, so that, the sum of the costs and losses is minimized at $48.99 million with optimal concentration threshold limit of 2450 mg/l at the discharge points and with an average of 17.85% of the optimal treatment at the loading points.