EN
A packed-bed bioreactors with activated carbon particles as a cerrier for iron-oxidizing bacteria was used for ferrous sulfate oxidation.The bioreactors were operated continuously for about 2 weeks.The experimental variables were: dillution rate, pH, medium composition and Fe(II) ions concentration.It was found that the efficiency of iron oxidation depended on the dilution rate and the medium pH.As dilution rate increased, the oxidation rate was decreased but at the same time reacto productivity was improved.The highest kinetic performance achieved in single stage fermentation related to the Fe(II) oxidation was over 90% when D was below 0.2/h.The pH optimum was 1.3. At higher pH values a ferric iron precipitation was accelerated.It was showed thet replacement of the 8K medium with tap water has not had a negative effect on iron oxidation process.