Water Quality Goal Management Based On A Simulation Modelcoupled With Optimization

China has a huge population,a small amout ofper-capita and unbalanced distribution water resource,people use itunreasonablyand the pollutionis serious.Our country's water environment management concept is total volume control method and short of the target of ecological environment protection.There are more management departments,and the mangement is very confused and complicated,then there aredispute at the cross boundary section because of the different administrative areas.So the technology should achieve the goal of water environment quality standard and function in watershed.Mathematic models have played an important role in pollution control.Hydrodynamic and water quality modelshave been used to describepollution migration and transformation processes in water bodies,optimization models have been widely used to allocate pollution loads.The simulation model is the constraint condition for the optimization model,that can constitute simulation optimization model,but its modeloutputshave ongoing issues.A risk-explicit interval linear program(REILP)is a computationally efficient approach to solving problems of optimal waste load allocation.However,theREILP model cannot discriminate between different pollution sources,when it is used forequitable waste load allocation.This study proposes an improved simulation-optimization approach to solve problems of pollution load allocationl with an equity objectiveand constraint condtions added,which resulted in a lower system aspiration level,alower risk level,and a higher pollution load reduction ratio,this improved simulation-optimization approach can apply to any watershed.With the improved approach,decision makers can choose a tradeoff between the pollution load reduction ratio,pollution risk and reduced equityin the discharge points.This paper rearches the Jiangsu and Shanghai transboundary zone,Taipu River and Wusong River.The data is monitored from January to Decmber in 2013 exceeding pollutant need to be reduced in the transboundary control section.The improved simulation-optimization approach applies to Su-Hu transboundary zone,the exceeding indices are chemical oxygendemand(CODMn)and total nitrogen(TN).To ensure that the indices arenot excessivein the transboundary control section,the approach can compute the exceeding indices values which are allocated to different towns,then it can achieve volume control.Compared to the original REILP model,the best system aspiration is a lower levelrank order,the reduction of oxygendemand(CODMn)and total nitrogen(TN)is more,the risk level is lower.The reduction rates between all discharge pointsachieve equtiy in different the system aspiration level;the proportion of the pollution reduction ratio of discharge points andthe average pollution reduction ratio,that equals the proportion of pollution load of discharge points and the average pollution load.The Wusong River is different with the Taipu River,it has two tributaries,when it uses the original REILP model,the reduction ratio is not the highest.But when it uses the improved simulation-optimization approach,the regularitiesof the normalized total load reduction,normalized risk level and equity among all discharege pointsare the same as the Taipu River.