Advanced control of a wastewater treatment plant

The aim of this paper is to design a multivariable H-infinity controller for a wastewater treatment plant. The use of advanced control strategies for such processes is necessary because wastewater plants have a nonlinear behavior and are extremely sensitive to the influent flow and load. Nonlinear mathematical models usually present a higher accuracy than the linear mathematical models, but due to their complexity, are difficult to use in control system design stages. The present approach uses a simple linear model of the process; an operational model that describes its most important properties. The use of an advanced control algorithm like H∞ robust design method, that takes into account the model uncertainties, came as a solution to counter act the simplifications introduced by using the operational mathematical model. The assessment of the developed control system is done by numerical simulation using the Matlab/SIMULINK environment.