Generation of polluted waters from mining wastes in a uranium deposit.

Dump consisting of 9500 tons of rich-in-pyrite mining wastes located in the uranium deposit Curilo, Western Bulgaria, was, after rainfall, an intensive source of acid drainage waters. These waters had a pH in the range of about 1.7-4.

In situ bioremediation of soil contaminated with oil and heavy metals.

An experimental plot of soil contaminated with crude oil and heavy metals (copper, zinc and cadmium) was subjected to bioremediation using the activity of the indigenous soil microflora. The oil was light, rich in paraffins and with a very low content of asphaltene-resinous substances. Copper, zinc and cadmium were present mainly as sulfide minerals but also in forms more amenable to biological and chemical leaching.

Treatment of waters polluted with crude oil and heavy metals by means of a natural wetland.

In the Dolni Dubnik oil deposit, Northern Bulgaria, waters polluted with crude oil and heavy metals (iron, manganese, zinc, cadmium, lead, copper) were treated by means of a natural wetland located in the deposit. The waters had a pH in the range of about 4.5-6.