Treatment of acid drainage from a uranium mine by means of a passive system

摘要

Acid drainage waters from an uranium mine were treated by means of a pilot-scale passive system consisting of an anoxic cell and a constructed wetland arranged in a series. The anoxic cell was filled with a mixture of biodegradable solid organic substrates (spent mushroom compost, sawdust and cow manure) and was inhabited by a mixed microbial community consisting of sulphate-reducing bacteria and other metabolically interdependent microorganisms. An efficient removal of the pollutants was achieved in the anoxic cell. The microbial dissimilatory sulphate reduction and the biosorption were the main processes involved in this removal. The effluents from the anoxic cell were enriched in dissolved organic compounds. These compounds were efficiently degraded in the constructed wetland, which was characterized by an abundant water and emergent vegetation and a diverse microflora.