Linearizing control of the anaerobic digestion with addition of acetate (control of the anaerobic digestion)

In this paper the principle of linearizing control was applied to anaerobic digestion of organic wastes with addition of a stimulating substance (acetate). The objective consisted of regulating the biogas flow rate in the case of variations of the inlet organic pollutant. For this purpose, a new control input was introduced in the fourth order model of the process, which reflects the acetate addition. Laboratory experiments were done with step changes of this new input. New values of the model coefficients were obtained. Input-output characteristics and optimal steady states were derived analytically using different optimality criteria. The results obtained may be useful for industrial biogas plants operating with mixtures of organic wastes, where organic waste rich in acetate (e.g., vinasse) will be added as a stimulating substance.