Organic fractions influence on biogas generation from potato residues. Kinetic model generalization

• The effect of different organic fractions on the anaerobic degradation process was studied.
• The variable that most affects the whole degradation process is the total organic load.
• A generalized model that considers fluctuations on feed was developed and fitted.
• The capability of the model to predict the process behavior after was demonstrated.

Bioenergy production as methane is being increasingly used to process low value by-products or not commercial wastes, in particular those which contain high levels of biodegradable organic matter such as potato residue. This work is a continuation of a previous one, which details the characterization and development of a kinetic model for its biodegradation. The knowledge of the effect of different fed organic fractions on the kinetics allows the development of kinetic models that predict the behavior of the degradation after a fluctuation in the feed characteristics. Information about the influence of each variable over different process stages was found and a generalized model was developed in concordance. It considers: substrate inhibition in the hydrolysis step and uncompetitive inhibition by total organic load in the stage of degradation of the biodegradable soluble material, and the yield of methane. Furthermore, the biomass influence was taken into account on each stage. This generalized model has been successfully able to predict the evolution of the different species throughout the whole range of conditions studied with a single set of parameters.