EN
A packed-bed bioreactor with activated-carbon particles as a carrier matrix material inoculated with Thiobacillus ferroxidans was operated at a pH 1.30 to convert ferrous sulfate to ferric sulfate.The experimental variables were dillution rate, medium composition and Fe (I) ion concentration.The reactors were operated within a dillution rate range of 0.013 to 0.560/h and within a ferrous sulfate concentration range of 20 to 40 g/l.The aeration rate was 5-7 l/h.It was showed that replacement of the 9k medium with tap water had no negative effect on iron oxidation process.