Stable adaptive controllers for waste treatment by anaerobic digestion

Abstract This paper deals with the control of waste treatment plants by anaerobic digestion. Continuous‐time adaptive schemes are proposed for single‐step (methanization) and two‐step (acidification plus methanization) plants. The stability of the algorithms is demonstated by using Lyapunov functions, in both the disturbance‐free and the bounded disturbance cases. The effectiveness of the algorithms is illustrated by simulation experiments. An important feature of the proposed algorithms is that they do not require any analytical description of the microbial specific growth‐rate.