Nonlinear adaptive stabilizing control of an anaerobic digestion model with unknown kinetics

In this paper, we consider a nonlinear model of a biological wastewater treatment process, on the basis of two microbial populations and two substrates. The model, described by a four-dimensional dynamic system, is known to be practically validated and reliable. We propose a feedback control law for asymptotic stabilization of the closed-loop system towards a previously chosen operating point. A numerical extremum seeking algorithm is applied to stabilize the dynamics towards an equilibrium point with maximal methane flow rate. Computer simulations are reported to illustrate the theoretical results. Copyright (C) 2011 John Wiley & Sons, Ltd.