A nonlinear observer for activated sludge wastewater treatment process: Invariant observer

AbstractAbstractAn activated sludge wastewater treatment process model is concerned in this paper. In order to estimate the variables that cannot be measured online, an invariant observer for activated sludge wastewater treatment process is presented. The invariant observer can measure biomass concentration, substrate concentration and dissolved oxygen concentration in high accuracy and rapidity. Meanwhile it can be structured by means of typical form, and its robust convergence property is verified by theoretical analysis and numerical simulations (matlab).