Case Studies
Rapid Response and Remediation for Gasoline Pipeline Release: Ohio River, KY
The Situation:
An undetected breach in an underground gasoline pipeline resulted in the release of more than 200,000 gallons of gasoline to a shallow aquifer. Dispersion of the gasoline plume was resulting in seepage of gasoline to the nearby Ohio River, a major waterway under U.S. Coast Guard jurisdiction. In addition, a deeper aquifer used by the local municipality as the public water supply for approximately 100,000 customers was under threat of groundwater contamination from the gasoline release.
The Challenge:
Piedmont Geologic was tasked with a three-fold rapid-response strategy: 1) cut-off migration of gasoline on the water table to the Ohio River; 2) characterize and mitigate potential impacts to the municipal water supply; and 3) delineate the lateral and vertical distribution of contamination resulting from the gasoline release. Longer-term project challenges included development and implementation of a long-term site corrective action plan to control and mitigate the entire 3+ acre contaminant plume.
The Means:
Piedmont Geologic was onsite within one day of notification and began gasoline recovery and groundwater remediation activities within two days of notification. Initial response actions included installation and commissioning of closely spaced gasoline/groundwater recovery wells along the width of the riverbank seepage area to cut-off further migration of gasoline to the Ohio River. In addition, Piedmont Geologic implemented and managed round-the-clock river seep abatement measures until gasoline seepage to the river subsided due to the effects of the recovery system. A mobile dual-phase vacuum extraction system was activated at the site to recovery gasoline from monitoring wells as the groundwater assessment proceeded. Aquifer and gasoline baildown testing was conducted to determine subsurface gasoline thicknesses and aquifer characteristics. Pump testing of municipal water supply wells was conducted to evaluate potential impacts to the municipal water supply from the site contaminants.
The Result:
A total of approximately 30,000 gallons of gasoline has been recovered through the initial 6 months of site remediation efforts. Seepage of gasoline to the Ohio River has been largely mitigated through the riverbank recovery efforts. One nearby municipal water supply well has been decommissioned as a precautionary measure and pumping of other nearby municipal water supply wells is being closely monitored. State and Federal regulatory authorities have expressed satisfaction regarding the responsiveness and effectiveness of Piedmont Geologic’s efforts at the site.
Future Plans:
Plans are being developed for implementation of a full-scale, long-term, groundwater remediation strategy during the fall of 2009. A combination of remediation technologies is planned, including total fluids recovery, soil vapor recovery, thermal oxidation, and groundwater remediation by natural attenuation.
