Universal optimization of water quality management strategy

Although many optimization models for water quality problems have been developed, methodology for judging the necessity of applying them is scarcely worked out. The universal optimization scheme presented here is to determine a management strategy for controlling water quality in a generic body of water. Dynamics of a water quality index is represented by an ordinary differential equation, and a linear system model is deduced. The H∞ control theory, which summarizes system stabilization and error minimization, is applied to a generalized water quality control problem including the linear system model. A class of H∞ controllers is identified, and a temporal discretization scheme for a controller is proposed. Three application examples demonstrate the conception of universal optimization and the validity of its implementation using an H∞ controller.