The process waters formed in amount of 150 dm3 per ton of retorted oil
shale are directed to the first treatment stage deoiling. Process waters are
deoiled to obtain water-soluble phenols of required quality. These waters are
purified from emulsified oils by the method of countercurrent flow extraction
in the deoiling column. Gasoline fraction of shale oil, boiling to 180 oC,
is used as extractant for emulsified oils [1].
Water with residual oil content of 2040 mg/L and phenol concentration
of 611 g/L enters the next purification stage dephenolation.
Dephenolation process serves two goals: water purification and obtaining
marketable products total water-soluble phenols. It is possible to direct the
dephenolated water for additional extraction of water-soluble phenols from
the shale oil fraction 230320 oC, and to redirect it to dephenolation (with oil
content of 3550 mg/L). It would both increase the yield of water-soluble
phenols and reduce the amount of water given to the biological treatment.
Dephenolated water is led together with industrial and domestic wastewater
to the third stage biological treatment. The effluent is treated in two