Mathematical Modeling and Static Characteristics of the Anaerobic Digestion of Organic Wastes with Production of Hydrogen and Methane

In this paper, static characteristics of five different mathematical models of a two-stage anaerobic digestion (AD) process for the sequential production of Н2 and СН4 are derived. Different process variables are described in the considered mathematical models. Each subsequent model describes in more detail the two-step AD process under consideration. The concentration of the influent organic matter is assumed to be the main external disturbance reflected in the models. Changing it leads to a shift of the corresponding static characteristics without changing their essence, but of course the value of the maximum also changes. The obtained specific values of dilution rate in the first bioreactor (D1) and dilution rate in the second bioreactor (D2) are highly dependent on the parameter values in the 5 models considered. On the other hand, the model parameters are dependent on the specific substrate in the AD process. Thus, the values of D1 and D2 are highly dependent on the substrate used.