The Client retained Geosyntec to lead the implementation of a Remedial Design/Remedial Action (RD/RA) for a Superfund site at the location of a former manufacturing operation. Primary chemicals of concern at the site were polychlorinated biphenyl (PCB) in soil and perchloroethylene (PCE) in groundwater. The work was performed to meet the requirements of a Record of Decision, under the review and approval of the U.S. EPA Region IV and the North Carolina Department of Natural Resources (NCDNR) Division of Waste Management.
Geosyntec’s Scope of Services
Geosyntec led the project team in developing the design documentation for the soil and groundwater remediation. A discharge wetland on site contains a federally-endangered plant species that is sensitive to small changes in the water table elevation. The U.S. Fish and Wildlife Service recognized that the planned pump-and-treat system could have a negative impact to the sensitive plant. Therefore, one of our primary design objectives was to maximize hydraulic containment of the plume while minimizing drawdown at the wetland.
Geosyntec’s design investigative activities included: i) surface geophysical and soil gas surveys; soil, ii) groundwater, surface water and sediment sampling, iii) wetland assessments, and iv) a bioremediation treatability study. Our remedial activities included soil excavation (with relocation of residents), landfill capping, and groundwater extraction and treatment. On behalf of our client, Geosyntec assisted in regulatory negotiations with the U.S. EPA Region IV and the NCDNR Division of Waste Management.
Geosyntec used a three-dimensional groundwater model to develop the optimum groundwater extraction design that provided hydraulic containment while minimizing potential impacts to wetlands and a federally-endangered plant species. The total number of wells and extraction rates were significantly less than the initial design by others which was intended for full hydraulic containment. The groundwater treatment system was designed and constructed to reuse treated water in the manufacturing facility to optimize the use of natural resources. Geosyntec continues to perform treatment system operation and maintenance, performance monitoring, and system optimization