ABSTRACT
Microbial oxidation of ferrous iron may be a viable alternative method of producing ferric sulfate, which is a reagent used for removal of H(2)S from biogas. The paper introduces a kinetic study of the biological oxidation of ferrous iron by Thiobacillus ferrooxidans immobilized on biomass support particles (BSP) composed of polyurethane foam. On the basis of the data obtained, a mathematical model for the bioreactor was subsequently developed. In the model described here, the microorganisms adhere by reversible physical adsorption to the ferric precipitates that are formed on the BSP. The model can also be considered as an expression for the erosion of microorganisms immobilized due to the agitation of the medium by aeration.
Subject(s)
Biofilms , Bioreactors/microbiology , Ferrous Compounds/metabolism , Iron/metabolism , Models, Chemical , Thiobacillus/metabolism , Adsorption , Bacterial Adhesion , Biomass , Chemical Precipitation , Culture Media/metabolism , Ferric Compounds/metabolism , Kinetics , Logistic Models , Oxidation-Reduction , Oxygen/metabolism , Substrate Specificity , Thiobacillus/classification , Thiobacillus/growth & developmentABSTRACT
A variation on Ramsay's method for microbial protein determination has been developed in order to quantify Thiobacillus ferrooxidans attached to ferric precipitates or in aqueous suspensions containing such precipitates. Some modifications have been introduced to provide a method that is more sensitive, simple and rapid. A linear standard curve is presented to permit a direct correlation between the protein concentration (mg/l) and the cell concentration (10(6) cells/ml). An application of this method has been demonstrated in the quantification of biomass immobilized on the surface of polyurethane foam particles in a packed bed reactor, several experiments having been conducted to establish the best conditions for the quantification studies.