skip to main content

Seneca Landfill Completes Acid Mine Treatment System


This summer, Seneca Landfill, Inc. (Seneca) completed construction of an acid mine treatment system in Washington Township, Butler County on PA State Game Lands #95. The area was abandoned and left unreclaimed following past coal mining activity on the property. Acid Mine Drainage (AMD) from a seep known as SR89 was discharging directly into Slippery Rock Creek, polluting the water and damaging the aquatic ecosystem.

As part of a wetland mitigation project at Seneca Landfill, Seneca agreed to take the lead to clean up and mitigate one of the largest untreated AMD flows impacting the Slippery Rock Creek.

The 10-acre passive treatment system project incorporated the following elements:

  • Removal of over 3,000 yards of iron matting and contaminated soils.

  • Construction and stabilization of over 900 feet of stormwater collection ditches.

  • Construction of over 800 feet of limestone-lined, terraced, iron formation channels used for low pH iron removal.

  • Construction of a Jennings-style vertical flow treatment pond filled with a mixture of environmentally-friendly treatment media including over 1,000 yards of limestone, 500 yards of mushroom manure, and 1,000 yards of wood chips.

  • Removal and grading of over 60,000 cubic yards of soil as part of the construction and regrading of the site.

  • Construction of a final settling pond/wetland prior to discharge to Slippery Rock Creek.

The project has already proven successful at neutralizing the water in the area, raising the pH to around 7.0 from readings in the range of 3.0 earlier this year. The treatment system will continue to greatly improve the water quality of Slippery Rock Creek and bring relief to the ecosystems surrounding it.  

“We have been a family-owned business for over 60 years operating in Butler County and are proud to do our part in helping improve the water quality of the Slippery Rock Watershed,” said Edward R. Vogel, Vice President. 

Partners in the project included the Pennsylvania Department of Environmental Protection, Butler County Conservation District, Slippery Rock Watershed Coalition, PA Game Commission, Stream Restoration, Inc., D&S Excavation, and BAI Group. For more information, visit the Slippery Rock Watershed Coalition website.