Load Distribution Of Water Pollution In Panjin By System Dynamics Model

With the fast growing economy and over population problem, the stress putting on environment is more and more serious, especially the management of water resources. It is now becoming a global issue worldwide, and the problem of how to find a sustainable solution is of most importance. The water system was a highly complicated and non-linear system which included not only the water amount but also the water quality aspect. System dynamics was actually a powerful science dealing with the non-linear condition and multiple and complex feedback systems. Base on the above understanding, this research introduced system dynamics to simulate the water resource system in Panjin city, and it was carefully considered the water usage for agricultural, industrial and domestic purpose. Hence it showed how the waste load and waste discharge could affect the water resources in quality and quantity.A simulation-based system dynamics (SD) model was developed for allocating the waste load and supporting river quality management. Panjin section of Liaohe River in China was used as a study case to demonstrate the feasibility of the proposed methodology. The whole model building process included the causal relationship between various subsystems, the determination of equations for individual subsystems, the estimation of the parameters and the test the validity of the model.After the completion of building the model for Panjin city, another interesting point made by this research was to determine the total control of waste and waste allocation. The national surface-water environment function zoning of Liaoning Province was presented as a constraint in order to calculate the maximum allowable waste quantity for COD. In order to make sure the water quality for the next intersect, the research proposed a water contamination control programme, by comparing the contamination situation during the dry period, wet period and normal period, the interval of the pollutant distribution amount has been made. In conclude, in dry period, the range for industrial waste discharge was [17.40,23.59] and for agricultural waste discharge was [23.59,36.65]. During flat period, the total agricultural distribution was [22623,39739]. During wet period, because other intersections did not exceed the standard, it was allocated to Yitong River, Qingshui River and Zhaoquan He respectively. It indicated that in different circumstances, the loading of water system perform differently, hence it is important to adopt certain rules for different periods.