Environmental Engineering and Remediation
Remedial Design and Remediation

Operational Unit 1 (OU-1) Leading Edge of Plume Area (LEPA)

Marine Corps Air Station (MCAS) Yuma, AZ

The OU-1 LEPA of MCAS Yuma was a National Priority List (NPL) site. Groundwater contaminated with chlorinated solvents was historically extracted and treated using a Vertical Circulation Treatment (VCT) System. The VCT system filtered the groundwater using granular activated carbon prior to re-injection. In December of 2005, groundwater cleanup objectives were achieved at the LEPA; therefore, the VCT system was shut down.

Subsequent groundwater sampling, however, indicated that contaminant levels at the site were increasing. Therefore, it became the objective of MCAS Yuma, the Department of the Navy, the U.S. Environmental Protection Agency, and the Arizona Department of Environmental Quality to begin operating the system again. The LEPA was targeted to prevent contaminated groundwater from migrating off-site.

GCE was contracted by Naval Facilities Engineering Command Southwest (NAVFAC SW) to complete all maintenance and repairs required to return the system to operational status. GCE'S staff of fully trained professionals began this project by completing an Accident Prevention Plan. Once approved by the Navy Environmental Health Center and the NAVFAC SW safety officer, GCE began full scale field activities. The Scope of Work included sampling and replacement of the spent carbon; inspection, abandonment, and replacement of extraction and injection wells; replacement of submersible and transfer pumps, and replacement of all system filters and meters. Upon successful repair and upgrade of the system, GCE was contracted through NAVFAC SW to operate and maintain the VCT.

GCE's full-service capabilities allowed us to satisfy the needs of MCAS Yuma and NAVFAC SW, from safety document preparation, through construction, and operation/maintenance of this critical groundwater remediation system.