CONICET | Buscador de Institutos y Recursos Humanos

This work deals with an experimental and theoretical investigation of fluidized bed anaerobic biofilm reactors (FBABRs). The bioreactors are modeled as dynamic three-phase systems. Biochemical transformations are assumed occurring only in the fluidized bed zone but not in the free-support material zone. The biofilm process model is coupled to the system hydrodynamic model through the biofilm detachment rate; which is assumed as a first-order function of the energy dissipation parameter. Non-active biomass is considered as particulate material subject to hydrolysis. The model includes a scheme of complex substrate degradation and kinetic parameters selected from literature. The experimental set-up consists of two mesophilic (36±1ºC) lab-scale FBABRs with sand as inert support for biofilm development. The experimental protocol is based on step-type disturbances applied on the inlet substrate concentration (glucose and acetic acid) and on the feed flow rate considering the criterion of maximum efficiency as the reactor loading rate switching. The predicted and measured responses of the total and soluble chemical oxygen demands, volatile fatty acid concentrations, biogas production rate and pH are investigated. Regarding hydrodynamic and fluidization aspects, variations of the bed expansion due to disturbances on the inlet flow rate and the biofilm growth are measured. The empirical values of the rate coefficients for the biofilm detachment model are estimated.