BIOLOGICAL DESULFURIZATION OF ESTONIAN OIL-SHALE

Pretreatment of Estonian oil shale by thermophilic Sulfolobus acidocal darius and mesophilic Thiobacillus ferrooxidans in order to remove ino rganic sulphur compounds (pyrite) has been studied. Shake flask experi ments showed bacterial growth on the internal pyrite of the shale and no substrate toxicity. The bioreactor experiments demonstrated that th e oxidation of pyrite by S. acidocaldarius is especially fast (96 % in four days). However, to evaluate the economic feasibility of the proc ess, the high acid consumption of this oil shale has to be taken into consideration.