Modeling of hydrogen behavior and reduced product formation following perturbation with hydrogenic substrate in a methanogenic reactor

The purposes of this study are to develop a non-steady state model which can express hydrogen behavior and reduced products formation in a perturbed methanogenic CSTR and to investigate energetic and kinetic interaction such as hydrogen transfer between H₂ producers and consumers. Smith and McCarty (1989a, 1989b) obtained interesting experimental results on transient responses of the perturbed mixed-culture methanogenic CSTR receiving ethanol and propionate. In an experiment with a sudden addition of propionate and ethanol at steady state, they observed highly elevated H₂ pressure and formation of reduced products such as propanol and longer chained VFAs. The model was applied to the perturbation experiment introducing a new concept of H₂ transport between bacterial groups. Different H₂ concentrations are defined by making a hydrogen transport within a colony of H₂ producers and consumers. The modified model expressed the sudden change of H₂ pressure and the formation of the reduced intermediate products which brought relatively low H₂ concentration. Once kinetics and energetic of biochemical reactions are given, the model could be available for transient processes and for better understanding of interactions Between H₂ producers and consumers.