Nonlinear identification of an anaerobic digestion process

Anaerobic digestion in bioreactors is an important technology for environmental friendly treatment of organic waste. To optimize and control such processes accurate dynamic models of the process are needed. Unfortunately, modeling of anaerobic digestion often results in high order nonlinear models with many unknown parameters, a fact that complicates controller design. This paper attempts to circumvent this problem, by application of new recursive system identification techniques, thereby radically reducing the degree of the models and the number of parameters. Experiments show that a second order nonlinear model is sufficient for accurate modeling of the system