An undetected breach in an underground gasoline pipeline resulted in the release of more than 120,000 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.
Piedmont Geologic was onsite within one day of notification and began gasoline recovery and groundwater remediation activities within three 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. 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. An interim mobile dual-phase vacuum extraction system was activated at the site to recover gasoline from monitoring wells as the groundwater assessment proceeded. Remote sensing techniques, including Laser Induced Fluorescence (LIF) were employed to guide placement of monitoring and recovery wells. Aquifer and gasoline bail-down 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. Design, permitting, and installation of a full-scale total fluids extraction (TFE) and soil vacuum extraction (SVE) system was completed within one year of the release discovery.
• Halt seepage of gasoline on water table to Ohio River
• Identify the lateral and vertical spread of contamination resulting from the release
• Identify potential impact on nearby municipal water wells
• Design, install and operate a full-scale remediation system to mitigate the entire three acre contaminant plume.
Additionally, the client did not own any of the properties impacted by the release, which necessitated need for execution of access and remediation agreements with property owners to facilitate rapid response measures. Complex fluvial geological deposits required precise placement of monitoring and recovery wells to prevent cross-contamination between shallow and deeper aquifers.
Seepage of gasoline to the Ohio River was mitigated in less-than 2-months following the release discovery and initiation of riverbank free-product recovery efforts. Complete abatement of free- product throughout the 4-acre extent of the free-product plume on the water table occurred within 18-months of startup of the full-scale system, in conjunction with the recovery of approximately 120,000-gallons of free product. An air sparging system was then installed to augment the rate of dissolved-phase contaminant remediation, resulting in an approximately 90%+ reduction in the areal extent of the dissolved-phase contaminant plume over a 2-year period. Piedmont Geologic is now working with KDEP to develop a risk-based management plan for remaining site groundwater contamination, which will allow long-term development plans for the site property to proceed. State and Federal regulatory authorities have expressed satisfaction regarding the effectiveness of Piedmont Geologic’s efforts at the site. The pipeline owner has avoided additional regulatory fines as a result of Piedmont Geologic’s rapid response. Ongoing remediation and monitoring will move the site towards closure status.