BENCH AND PILOT SCALE TEST RESULTS PASSIVE TREATMENT OF ACID MINE DRAINAGE (AMD) AT THE FRAN COAL MINE, PA

The Fran Site is a 37-acre reclaimed surface coal mine in Clinton County, PA. Residual seepage from this site is reportedly the “worst AMD in the State of Pennsylvania”; only about 40 gpm of peak flow is enough to affect nearly six miles of three otherwise pristine streams which are tributaries of the Susquehanna River. The Fran Mine AMD is similar to acid rock drainage from metal mines in that it contains elevated concentrations of iron and aluminum as well as other heavy metals such as copper, zinc, cadmium, cobalt, chromium, and nickel and has acidity on the order of grams per liter. Experience has shown that AMD with these characteristics is amenable to a passive treatment technology that uses sulfate reducing bacteria to precipitate the heavy metals as sulfides and the aluminum as a hydroxy-sulfate mineral phase. Spearheaded by funding provided by the Allegheny Mountain Chapter of Trout Unlimited and other sources, bench and pilot scale tests of sulfate reducing bioreactors (SRBR’s) revealed that this innovative technology could successfully treat the Fran AMD without plugging with aluminum hydroxide. The design of a full-scale SRBR system is currently underway based on the bench and pilot scale experience.