Restoration of Stream Water Degraded by Acid Mine Drainage
ProblemAcidic, metal-laden drainage from abandoned coal mines is common in Appalachia and has a negative effect on aquatic resources including degradation of habitat and loss of important recreational fisheries. In Pennsylvania, the 3,000 miles of streams degraded by AMD create an estimated annual loss of $67 million in revenue associated with sport fishing. The cost for correcting the AMD-related problems with currently available technology is estimated to be $5 billion to $15 billion. Research at the USGS Leetown Science Center (LSC) in West Virginia has resulted in the development of a new AMD treatment technique to assist in stream restoration efforts. This new technology integrates fluidized-bed reactors with carbon-dioxide adsorption and desorption to circumvent problems that limit the effectiveness of limestone as an acid- neutralizing reagent (figure 1).
CollaboratorsUSGS-BRD worked with the National Park Service (NPS), the Freshwater Institute, and the Pennsylvania Department of Environmental Protection (PaDEP) with funds from the State Partnership Grant Program.
ActivitiesField tests of the fluidized-bed reactor technology were conducted to establish the effects of the treatment process on acid-sensitive aquatic invertebrates and fish at LSC's Research and Development Laboratory in Wellsboro, Pa. Field tests also were conducted at the PaDEP Toby Creek mine drainage treatment plant (Elk County) under the State Partnership Grant Program. An additional field test was conducted at the NPS Friendship Hill Historic Site (Fayette County) using NPS funds. Here performance of a large-scale system over an extended period of time was evaluated, as was the effect of treatment on stream biology. Studies at the site identify improved methods for heavy metal separation and sludge thickening.
Laboratory and field test results are documented in the following reports: "Carbon dioxide pretreatment of AMD for limestone diversion wells" (Watten, 1996, in Proceedings of the 17th Annual Meeting of the Surface Mine Drainage Task Force, Morgantown, WV) and "Physiological and Behavioral Responses of Stonefly Nymphs to Enhanced Limestone Treatment of Acid Mine Drainage" (Cole and others, 2001), in Water Research 35(3):625-632. U.S. patents 5,863,422 and 5,914,046 were awarded for "Process and apparatus for carbon dioxide pretreatment and accelerated limestone dissolution for treatment of acidified water," (Watten, 1999, U.S. Department of Commerce, Washington, D.C.).
Project ChiefBarnaby Watten