Showing papers on "Biofilm published in 1980"

Model of steady-state-biofilm kinetics

Abstract: A steady-state biofilm is defined as one that has neither net growth nor decay over time. The model, developed for steady-state-biofilm kinetics with a single substrate, couples the flux of substrate into a biofilm to the mass (or thickness) of biofilm that would exist at steady-state for a given bulk substrate concentration. Based on kinetic and energetic constraints, this model predicts for a single substrate that a steady-state bulk concentration, Smin, exists below which a steady-state biofilm cannot exist. Thus, in the absence of adsorption of bacteria from the bulk water and for substrate concentration below Smin, substrate flux and biofilm thickness are zero. Equations are provided for calculating the steady-state substrate flux and biofilm thickness for S greater than Smin. An example is provided to demonstrate the use of the steadystate model.

Evaluation of steady-state-biofilm kinetics

Abstract: Laboratory-scale biofilm reactors were used to evaluate a model of the kinetics of steady-state biofilm and the concept that there is a minimum concentration, Smin, below which no steady-state activity can occur. With acetate as the ratelimiting substrate, the steady-state concept of Smin was verified for naturally grown biofilms. Substrate removal and biofilm thickness declined rapidly as the substrate concentration approached Smin, which was 0.66 mg/liter for acetate. Using independently derived kinetic parameters, the model of steady-state-biofilm kinetics successfully predicted substrate utilization and biofilm thickness without the need for fitting factors. The results imply that organic materials may persist in water and wastewater, in part, because they are too low in concentration to supply sufficient energy to sustain the microorganisms.