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Mathematical model parameters for the methanogenic degradation of propylene glycol were estimated in a sequential manner by means of an optimization technique. Model parameters determined from an initial experimental data set using one bioreactor were then verified with the results from a second bioreactor. The proposed methodology is a useful tool to obtain model parameters for continuous flow reactors with completely mixed regime. Abbrevations:S – substrate concentration (mg COD l-1); Sin – influent substrate concentration (mg COD l-1); DL – dilution rate (day-1); κ – stoichiometric coefficients (ND); nx – number of microbial species (ND); XS – fixed biomass concentration (mg biomass l-1); XL – suspended biomass concentration of (mg biomass l-1); kd – decay rate of biomass (day-1); bS – specific detachment rate of biofilm (day-1); μ – specific growth rate of biomass (day-1); μm – maximum specific growth rate of biomass (day-1); KS – half saturation constant (mg COD l-1); KI – inhibition constant (mg COD l-1). [ABSTRACT FROM AUTHOR]

Bed segregation in a fluidized bed bioreactor profoundly influenced biofilm thickness and microbial activities of the biofilm along the bed height. Bioparticles coated with a thin biofilm, observed at the bottom of the reactor, had a higher specific activity in propylene glycol and n-propanol degradation than in thick biofilms developed at the top of the reactor. Although no significant difference was observed in specific activity for propionate and acetate along the reactor flow axis, more total propionate and acetate conversion occurred in regions of thicker biofilm accumulation. [ABSTRACT FROM AUTHOR]