Bifurcation analysis of an anaerobic digestion system

This paper presents the bifurcation analysis of an anaerobic digestion model, which includes hydrogen production along with methane production. Analytical expressions of the equilibria are given and the conditions for their occurrence are provided. The analytical developments are validated by means of bifurcation diagrams built with specialized continuation software. Special emphasis is put on revealing the relationship between hydrogen and methane outflow rate. The complex system behavior is illustrated by means of phase portraits.