A Simulation-Based Optimization Approach for Water Quality Management of Xiangxihe River Under Uncertainty

A simulation-based interval quadratic programming (IQP) method was developed for river water quality management, where uncertainties associated with water quality parameters, cost functions, and environmental requirements were described as interval values. IQP was applied to a real-case study of the Xiangxihe River, China. A multisegment simulation model of one river with one tributary was used to generate water-quality transformation matrices and vectors, which were used to establish the river water quality constraints; in addition, the cost function of wastewater treatment were expressed as quadratic form. System cost, wastewater treatment efficiencies, and river pollution situations were analyzed under two scenarios and three criteria. A number of cost-effective schemes were generated by adjusting different combinations of decision variables within their solution intervals. Results can help decision makers generate alternatives between wastewater treatment cost and stream water quality requirement under uncertainty.