The U.S. Bureau of Mines conducted a laboratory study to determine if sulfate-reducing ecosystems can effectively treat acid mine drainage in the presence and absence of calcareous substrates. Four anaerobic mesocosms (20 l) were created in the laboratory by inundating carboys containing spent mushroom compost and allowing native species of fermentative organisms and sulfate-reducing bacteria to become established. The mushroom compost in two carboys was underlain by calcareous gravel; the other two carboys contained a noncalcareous gravel substrate. Simulated acid mine drainage was passed through each carboy, and samples of the inflow and outflow were analyzed to determine ph, acidity, alkalinity, and concentrations of iron, manganese, sulfate, and calcium. At influent ph 4 to 5, about 90 pct of the iron and 80 pct of the manganese were removed with a single pass through the mesocosms. At influent ph 2.5 to 3.5, About 80 pct of the iron and 50 pct of the manganese were removed. About 55 pct of the sulfate was removed irrespective of influent ph. All effluents from the mesocosms exhibited a circumneutral ph and had slight net alkalinity. The presence or absence of a calcareous substrate did not significantly affect the ph and alkalinity of the effluents or the quantity of iron and sulfate removed. However, mesocosms with calcareous substrates were more effective in removing manganese. Results of this study indicate that existing anaerobic organisms will remain active in the presence of acid mine drainage and significantly improve water quality.
Proceeds, 9th Ann. W. V. Surface Mine Drainage Task Force Symp., Morgantown, West Virginia, 4/25-26/89