Estimation and optimal control design of a biological wastewater treatmentprocess

This paper deals with the on-line estimation and optimal control of a biolo gical wastewater treatment process. The objective of the; control is to for ce the residual substrate and the dissolved oxygen concentrations to track a given reference model despite the disturbances and system parameter uncer tainties. The control law is based on one step ahead prediction of the cont rolled variables and minimization of an appropriate quadratic cost function . The technique is based on direct exploitation of the nonlinear model repr esenting the wastewater treatment process and is coupled with an asymptotic estimator for on-line tracking of simultaneously unavailable states and ti me varying parameters. The estimated variables are used in the explicit des ign of the control algorithm according to certainty equivalence principle. A simulation study subject to measurement noise and abrupt jumps in the kin etic parameters shows the feasibility and robustness of the control strateg y. (C) 1999 IMACS/Elsevier Science B.V. All rights reserved.