Tracking substrate trajectories in continuous aerobic wastewater reactors via nonlinear PI controllers

Abstract

This work addresses the problem of robust tracking of the substrate concentration in a continuous bioreactor in an industrial wastewater treatment plant of an oil refinery. The entire nonlinear operating region of the process was approached by several linear models. The suggested global controller is designed considering an average between the linear single controllers designed for each operating region. The averaging methodology is conducted via interpolation, considering Gaussian distributions as the interpolating functions. The robust properties of the global controller are shown by employing a Lyapunov function. The corresponding performance of the proposed methodology is illustrated via numerical simulations.