Description: An innovative passive treatment system was installed as part of a larger Public-Private Partnership effort among the US Army Corps of Engineers, PA DEP BAMR, PA Game Commission, Elk County Conservation District, Bennetts Branch Watershed Association, P&N Coal, and others to restore the Dents Run Watershed. At the PA3895 site, an innovative passive treatment system was designed by BioMost, Inc to treat several abandoned mine discharges in Porcupine Hollow, one of the most polluted tributaries to Dents Run. The system contains one of the first, if not the first, instance of intentionally constructing low pH iron oxidation and precipitation channels that utilize naturally occurring iron oxidizing bacteria to remove iron at low pH. In addition, the system used an alkaline iron mine discharge to help treat the extremely acidic metal bearing discharges.