CLEANING METHOD OF CERTEJ MINE WATERS, IN ORDER TO DISCHARGE THEM IN EFFLUENTS.

Mining activities for underground and surface extraction of useful minerals generate a change in local hydrostatic levels, requiring the drainage of the resulted water. Owing to water contact with the existing mineralization, mine waters are generally loaded with suspended material and heavy metal ions and have an acid pH. The mine waters continue to be polluting factors for that area and for water courses, even if the mining activity is closed. Therefore is particularly important to study the limitation of polluting effects of mine waters and if possible, the recovery of useful metals from them. The paper goal is to present the characteristics of mine waters from Certej mining area, the suitable techniques for mine water cleaning and finally, some results of a first research stage, applying a method of mine water treatment based on the co-precipitation of heavy metal ions with lime. The research has revealed the conditions in which heavy metal ion content decrease can be realized in order to meet the quality conditions for waters discharged in natural receptors. Except the lead ions (that have the content within the allowed limits) the efficiency of heavy metal ion content reduction was of over 93%, in the determined working conditions. It has been established the requirement for the flocculent dosage and consumption in the precipitate decantation phase and the aeration of clean water, to reduce its alkalinity under the allowed limit (pH=8.5). [ABSTRACT FROM AUTHOR]