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Presented at the NABS Annual meeting, Pittsburgh, Pennsylvania, 2002
in Restoration Ecology
THE LONGEVITY AND LONG-TERM EFFECTIVENESS OF PASSIVE TREATMENT SYSTEMS IN REMOVING METALS AND ACIDITY FROM ACID MINE DISCHARGES.
M.A. Schrecengost, B. George, T.O. Morrow, and A.M. Turner. Department of Biology, Clarion University, Clarion, PA 16214
Acid mine drainage (AMD) is a large contributor to the degradation of water-quality in Pennsylvania's streams. AMD discharges can be very acidic and contain high concentrations of dissolved metals, iron, aluminum and manganese. Passive treatment systems are designed to remove metals and add alkalinity to the polluted discharges over a long-term basis by channeling the discharges through anoxic limestone drains and artificial wetlands. Previous studies have shown that passive treatment systems are effective at removing contaminates from discharges, but there is little information on their longevity and long-term effectiveness. We evaluated the long-term performance of eight systems ranging in age from six to eleven years, installed in the Mill Creek watershed of western Pennsylvania. Water samples, collected periodically since the installation of each system, were tested for acidity, alkalinity, iron, aluminum, manganese, and sulfates. The efficiency of five of the eight systems monitored remained fairly constant over time while two diminished. However, one system's efficiency progressively increased. Efficiency of the systems may be improved with the implementation of periodic maintenance. Based on data collected, passive treatment systems are able to remain effective over a period of at least eleven years.
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