The exploitation of lignite deposits is linked with the necessity of lowering the groundwater table and dewatering the mine of precipitation. A large percentage of the discharge waters requires purification prior to delivery of receiving streams. The chief pollutants of these waters are the oxygen demand, and occasionally high iron. Purification of these waters is limited, as a rule, to a reduction in suspended matter and turbidity. The method most commonly used is sedimentation in large sedimentation basins. For some difficult to purify mine waters and during periods of adverse atmospheric conditions, this technology does not produce satisfactory results. To improve sedimentation basin efficiency studies were conducted using flocculants. The dependence of purification on the length of fast mixing, flocculant dose rates, and concentration of solutions employed were evaluated. The laboratory results were verified in a pilot scale sedimentation basin. The scope of the research included studies of the hydraulics of the sedimentation basin and investigations of flocculant application. The relationships between the dose of flocculant and time of retention and the reduction of suspended solids, turbidity, oxygen demand and other chemical parameters were made. Results of pilot tests confirmed the usability of cationic polyelectrolites in purification of mine waters.

"April 1979." "Contract 05-534-3." "Project Officer Ronald Hill, Resource Extraction and Handling Division." Includes bibliographical references.