In Situ Treatment of Acid Mine Drainage by Sulphate Reducing Bacteria

摘要

The aim of this in-situ treatment is to use flooded open pits and mine shafts as largereactors to treat AMD with sulphate reducing bacteria. In this treatment method, bacterialgrowth and metabolism are stimulated directly in the contaminated water body and themine itself is used as a sedimentation basin for metal sulphide sludge formed byprecipitation. In order to promote bacterial growth liquid, manure or other anaerobicsludge is added into the open pit or underground mine. The study was conducted in the laboratory and two closed mine areas in Finland. First, aseries of laboratory tests were done in order to investigate the amount of bacteria neededand the effect of environmental conditions, such as low temperature and availablenutrients and organic material in the bacterial activity and treatment efficiency. A full-scale application was started in Kangasjarvi open pit. So far, clear bacterial action hasbeen observed, but the start up of the full scale action requires a few years. The secondtest site was Kotalahti mine, where the results have been very promising; the pH value ofmine water has increased and the metals and sulphate have been precipitated almostcompletely.