Use of Abandoned Mine Drainage for the Development of Unconventional Gas Resources

Abstract

Wastewater generated by natural gas extraction from Marcellus Shale activities and abandoned mine drainage (AMD) are the two most significant environmental concerns in Pennsylvania for their potential impacts on surface and groundwater. Reuse of Marcellus Shale wastewater for hydraulic fracturing represent an innovative solution that reduces potential environmental impacts of this industry. Because abundant AMD sources exist in the vicinity of shale gas extraction sites, it would be beneficial to utilize AMD as makeup water for hydraulic fracturing operation and reduce the impacts of this legacy issue from another energy-related industry in the region. This approach would alleviate demand for fresh water by the gas industry, reduce environmental impact of AMD, reduce the cost of water transportation for hydraulic fracturing, reduce the greenhouse gas emissions by the gas industry and reduce the cost of wastewater treatment before reuse for hydraulic fracturing. However, this approach has never before been tried by the unconventional gas industry and barriers to implementation range from technical issues to regulatory concerns. Technical issues include compatibility with fracturing chemicals, excessive scaling and biological growth in the well, and management of solid waste that would be generated by mixing these water sources. Regulatory issues include liability for perpetual AMD treatment that is implied by current regulations. These issues are discussed together with potential solutions based on original studies and review of the literature.