Cleaning of Acid Mine Drainage from An Uranium Mine By Means of a PassiveTreatment System

Abstract

Acid mine drainage containing uranium, radium, iron and some non-ferrous metal ions were treated under pilot-scale conditions by means of a passive system consisting of an anoxic pond, an alkalinity producing anoxic drain, an aerobic wetland, and an anaerobic cell, arranged in series. In the anoxic pond containing a mixture of cattle manure and straw the content of the dissolved oxygen in the waters was reduced and most of the ferric ions were turned into the ferrous state to avoid deposition of metal precipitates within the subsequent alkalinity producing drain. In this drain the alkalinity of the waters was increased as a result of their contact with crushed limestone under anaerobic conditions. In the aerobic wetland iron was removed as iron hydroxide and radioactive elements were removed mainly by sorption by the emergent vegetation and microbial biomass grown in this wetland. Finally, in the anaerobic cell sulphate and metals were removed and additional alkalinity was produced as a result of the activity of sulphate reducing bacteria.

Keywords:

• Acid mine drainage
• waste water treatment
• passive treatment systems
• constructed wetlands
• sulphate reducing bacteria
• heavy metal ions
• uranium mines