Complex Treatment of Drainage from Tailing Pond of Hydrometallurgical Plant Processed Uranium Ore

Abstract

Since 1990, the mining and processing of uranium ore have undergone a process of liquidation in Bulgaria. From the tailing pond of the uranium hydrometallurgical plant located in Buhavo, 30 km northeast of Sofia in Southwestern Bulgaria, up to 140 m3 of wastewater polluted with natural radionuclides, sulfate and manganese ions have been drained each day. In a period of experimental work, a biotechnological system with three biobasins (wetlands type), has been constructed to treat tailing pond drainage; this was put into operation in June 1994 (patent pending in Europe). The present work demonstrates the potential of the biotechnological system for removing radioactive and toxic contaminants from the drainage. The results obtained have indicated that improvement in water quality was definitely realised. For instance, by using natural, biological, chemical and physical processes at a retention time (RT) of 36 hours, between 8 to 18% of sulfate ions were removed from the drainage. These processes succeeded best in removing radium-226 (94 to 99%) and uranium (57 to 77%) from the tailing pond.