Treatment of waters polluted with radioactive elements and heavy metals by means of a laboratory passive system

Waters polluted with toxic heavy metals, radioactive elements, arsenic and sulphates were efficiently treated by means of a laboratory-scale passive system consisting of an anaerobic cell and a constructed wetland. These waters were polluted in a stream receiving leachates from an operating copper tailings dam and other effluents from man-induced activities at the area of Vromos Bay in Bulgaria. The anaerobic cell contained a mixture of horse, cow and sheep manure, spent mushroom compost, wheat straw and sawdust which were used as sources of carbon and energy by different metabolically interdependent microorganisms inhabiting the cell. The microbial dissimilatory sulphate reduction and the sorption on the organic matter were the main processes connected with the removal of pollutants. The effluents from the anaerobic cell were enriched in soluble organic compounds which were degraded in the constructed wetland containing rich microbial and plant cenoses. The effluents from the constructed wetland were suitable for use in the agriculture and industry.