The Challenge
For 30 years, the DEP diverted water from the abandoned Barnes and Tucker mines (including Lancashire No. 15 Mine) from the Susquehanna River basin for treatment in a system that discharged into the Ohio River watershed. BAMR sought a solution that would restore flow to the Susquehanna River at the request of the Susquehanna River Basin Commission.
The Solution
The team of Veolia Water Technologies and Michael Baker Corporation was selected to design a 10.5-MGD acid mine drainage (AMD) treatment system utilizing Veolia's DenseSludge™ technology, along with a mine dewatering pump station.
The DenseSludge process reduces the volume of sludge for disposal and reduces treatment costs. Using standard equipment, the process relies on sludge recirculation techniques based on Veolia's process expertise to create sludge containing 25% solids, as compared to 2 to 4% achieved by conventional processes. As a result, the sludge volume is reduced by about 90%. In addition, with acidic waters, the sludge recirculation reduces lime usage and its associated cost.
Veolia was responsible for treatability testing, the mine water pumping and piping system, treatment process development including equipment specifications, general plant layout, specific structural, mechanical and electrical details related to the equipment selected, pumping and piping systems for the sludge disposal to boreholes, and instrumentation/controls for the entire project. Baker was responsible for overall project management, surveying, development of a plan for subdivision of property, wetlands delineation and permitting, hydraulic modeling, geotechnical and site civil work, building architectural design, utilities and specific structural, mechanic and electrical details.
The effluent from the treatment facility consistently meets the limits specified in Pennsylvania Code, Title 25, PA DEP Chapter 87 Subpart 102, Group A. Initially the treatment plant influent was acidic, but within a few months of plant operation, the influent water quality became net alkaline, taking on the characteristics of the greater mine pool. The improved influent water quality enabled BAMR and the Office of Surface Mining to enhance the system operation by adding a hydrogen peroxide treatment step that eliminates lime usage, minimizes sludge generation and reduces operating costs by an estimated $212,500 per year.
The Client
The Pennsylvania Department of Environmental Protection (PA DEP), Bureau of Abandoned Mine Reclamation (BAMR) is responsible for resolving problems that have resulted from past coal mining practices, including mining-impacted water supplies, in accordance with the Surface Mining Control and Reclamation Act (SMCRA) of 1977.
Key Benefits
- The 10.5-MGD effluent restored about 25 miles of the Susquehanna River.
- To benefit agriculture, the increased flow was earmarked to replace the amount of water used by farmers during low flow periods. Susquehanna River Basin Commission regulations require consumptive water users to compensate for their use.
- When treating acidic mine water, the DenseSludge process reduces alkali usage and its associated cost.
- Sludge generation is typically reduced by 90%, and the drier sludge reduces the volume of water that returns to the mine pool for re-treatment.