Optimal operation of a system of waste water treatment facilities

The problem of specifying an operating policy for a system of waste treatment plants is considered within the framework of modern control theory. The policy determines the percentage of Biochemical Oxygen Demand (BOD) which must be removed from each plant at each point in time and which minimizes the total operating costs in the system subject to penalty functions on the separation of the actual water quality from the stream standards. The system equations have been developed and the control law obtained for different types of penalty functions.