Ben Amos will present “Characterization & Remediation of CCR-Impacted Groundwater” at 8 a.m. PDT on October 26, 2021. Ben’s coauthor is Lane Dorman, Geosyntec.Stephanie Jones Cushing will present “In Situ Flushing – A Counter-Intuitive Groundwater Remedy at CCR Sites” at 10:30 a.m. PDT on October 26, 2021.
Ben Amos is a Principal Remedial Design Engineer based in Georgia with more than 11 years of experience focused on soil and groundwater remediation and the management of groundwater risks at large, complex sites, including those in the utility sector. His technical experience involves contaminant fate and transport in porous and fractured media, site investigation and characterization, and the selection, design, implementation and interpretation of innovative in situ remediation technologies for the treatment of a broad suite of contaminants, including chlorinated solvents, explosives, energetics, and inorganic constituents such as coal combustion residuals (CCR).
Stephanie Jones Cushing is an Environmental Engineer based in Washington, D.C. Stephanie has contributed to characterization, monitoring, and remedial action projects as related to USEPA’s Final Rule for regulation of coal combustion residuals. She has also conducted research using bacterial source tracking to model and predict the performance of watershed protection measures in Pennington County, South Dakota.
EUEC facilitates information exchange and fosters cooperation between industry, government, and regulators for the protection of our environment and energy security. EUECVirtual, held October 26-28, 2021, will serve as a preview for the organization’s March 10-11, 2022 annual conference, which will be held in-person and virtually at the Westin La Paloma Resort in Tucson, Arizona.
Geosyntec Participation
Characterization and Remediation of CCR-Impacted Groundwater
Presenter: Ben Amos, Geosyntec
Date and Time: Oct. 26, 2021 at 8:00 a.m. PDT
High resolution site characterization (HRSC) of groundwater downgradient of a suspected CCR impoundment release was performed using multiple tools to evaluate CCR groundwater impacts and serve as the basis for selecting and designing a groundwater remedy. HRSC at this CCR facility included: 1) surface geophysical surveys using electrical resistivity imaging (ERI) around CCR impoundments to evaluate zones of elevated specific conductivity as an indicator of CCR groundwater impacts; and 2) direct push technology (DPT) investigations for collection of relative hydraulic conductivity, real-time vertical profiles of electrical conductivity (EC), and depth-discreet groundwater samples. Once a conceptual site model was developed, a groundwater extraction system was designed, constructed, and brought online to address identified CCR impacts. The remedial system included installation of nine extraction wells with a total flow rate up to 250 gallons per minute. Due to concentrations of groundwater constituents, corrosion/scaling issues were predicted by geochemical modeling and subsequently observed during system operation. The potential for scaling was addressed through system design and as part of routine system operation/maintenance. Since system startup, routine groundwater monitoring indicates substantial declines in groundwater concentrations.
In Situ Flushing – A Counter-Intuitive Groundwater Remedy at CCR Sites
Presenter: Stephanie Jones Cushing, Geosyntec
Date and Time: Oct. 26, 2021 at 10:30 a.m. PDT
Many coal combustion residuals (CCR) disposal units regulated by the Federal CCR Rule will require Corrective Actions as statistically significant levels (SSLs) of Appendix IV constituents are detected above groundwater protective standards (GWPS) during Assessment Monitoring. The CCR Rule imposes stringent performance standards for Corrective Actions with the point of compliance (POC) at the edge of the CCR unit. Pump and treat (P&T) technologies might be necessary, or already in place, at some of these facilities. However, traditional P&T technologies are limited in their capacity to address unsaturated zones and lower permeability areas containing residual pore water with dissolved and sorbed constituent mass, such as between capped CCR units and the lowered groundwater table induced by pumping. When P&T systems are shut off and the groundwater table rebounds, these unsaturated zones and lower permeability areas may act as secondary sources of constituents to groundwater which could lead to detections above GWPS and additional Corrective Actions. Unlike traditional P&T technologies, in situ flushing targets unsaturated zones and lower permeability areas with clean water injection wells that mobilize residual pore water with constituent mass toward capture wells. In situ flushing has recently been embraced at a large CCR disposal site to mitigate unsaturated zones and lower permeability areas below CCR units from acting as secondary sources after P&T systems are shut off.
More Information
About the event: euec.com/2021-euec-virtual-october-1st/
About EUEC: (Appears to be no freestanding website for org)
For consultation regarding CCR-impacted sites, contact Ben at bamos@geosyntec.com or Stephanie at scushing@geosyntec.com.
Learn more about Ben: www.geosyntec.com/people/benjamin-amos
Learn more about Stephanie: www.linkedin.com/in/stephanie-jones-cushing-3b6826112/
