Many cities in the U.S. are faced with the problem of combined sewer overflows (CSOs). Combined sewers carry a mixture of municipal sewage and storm runoff. During storm conditions, the capacity of such sewers (and/or the associated treatment plants) may be exceeded and the combined sewage must be released to the environment untreated. Real-time control of the combined sewage conveyance system is a potential low cost solution to the problem. Regulating gates and pumps can be manipulated to maximize storage of peak loads within the system to minimize the CSOs during each storm event. The problem described above is the design of a control algorithm for a large-scale system. The PI plans to adapt Model Predictive Control (MPC) strategies and develop a control scheme for the Metropolitan West Seattle sewage collection system. The ultimate test of his control scheme will be on this real, full scale facility. Specifically the project involves: (1) optimization of the dynamic response of a plant in which there are many manipulated variables and many output variables, (2) forecasting of unmeasured plant disturbances, (3) accounting for inequality constraints on most output variables, and (4) incorporating plant dynamics that include integrator states, nonlinear characteristics, and lags and time delays.
