EVALUATION OF THE EFFICIENCY OF MEASURES FOR SULPHIDIC MINE WASTE MITIGATION

To control the environmentally detrimental impact of acid rock drainag e, two different countermeasures, layers of acid-buffering materials a nd sodium dodecyl sulphate addition, were tested for their efficiency in laboratory percolation experiments. In the experiment with a layer of calcium bentonite, only the iron output was reduced. The experiment s with layers of concrete grains demonstrated a decrease of the microb ial activity as well as a precipitation of heavy-metal ions, whereas t he cell numbers did not decrease. Furthermore, finely grained concrete (1-5 mm) formed a water-tight hard-pan (self-sealing layer). In the e xperiment with 1 mM sodium dodecyl sulphate, all the microorganisms we re killed and hence metal sulphide dissolution was stopped. With 0.1 m M sodium dodecyl sulphate only a short, transient inhibition of leachi ng was achieved. The bacteria remained alive.