Study of a theoretical approach to bioprocess modeling for the performance of an anaerobic digester

Anaerobic digestion represents one of the major challenges of sustainable development and circular economy in the concept "from waste to energy". Given the great diversity of organic waste, its development requires the optimization of co-digestion. Hence the need to develop simple tools to characterize substrates and to predict the performance of digesters in order to optimize their operation. In this work, an approach based on a simple mathematical model to be able to calculate the biogas yield was studied. The models studied (AM2 and ADM1), serve as a basis for the development of monitoring and regulation strategies, offering more or less detailed levels of description of the digestion process. We have identified a difference in complexity between these two models explained by the different objectives for which they were developed. Thus, our study aims to propose a theoretical approach to the modeling of bioprocesses by choosing between the two aforementioned models. The objective being to provide a certain ease to the biogas producer and designer of digesters in the rural world, the simple model chosen is justified by intermediate stages of lesser importance than the final stage of methanogenesis. Thus, the information collected and estimated can subsequently be used for control strategies to optimize the operation of the digester, or they can be used by monitoring and diagnostic systems. This model will give a synthetic vision of anaerobic digestion, which limits its use to the modeling of the treatment of simple effluents. On the other hand, its formulation will allow a thorough mathematical analysis, and its simple structure would be well suited to the development of control strategies or monitoring procedures.