A review of the role of hydrogen in past and current modelling approaches to anaerobic digestion processes

Anaerobic digestion is a consolidated technology for effective waste (water) treatment and biogas production. Despite many reported studies, the complex dynamic behaviour of the process is not completely understood, hindering its full exploitation. In particular, process start-up is delicate and disturbances can deviate the process from its expected course of operation. There is evidence in literature that hydrogen might play an important role, as an early indicating factor of dynamic behavioural changes. The objective of this article is to review the existing literature on mathematical modelling of anaerobic digestion, with a special emphasis on how the dynamics of hydrogen has been considered in existing models and how it could potentially be further exploited in future work.