Opal Group Inc.

Prewitt Site Remediation

ARCO/El Paso Natural Gas

Prewitt, NM

Contaminated source materials, contaminated ground water and NAPLs in fractured bedrock required remediation at this former 70-acre crude oil refinery 20 miles from Grants, New Mexico. Remediation consisted of first removing the source materials and subsequently extracting and treating NAPLs and groundwater from fractured sandstone underlying the site. Opal's personnel excavated near-surface lead, asbestos and petroleum hydrocarbon wastes from the West Pits and Separator areas for both on-site treatment and off-site disposal. A total of 377 cubic yards [yd3] of Asbestos-Containing Materials [ACM], 3,830 tons of lead-contaminated soils, and 207 tons of stabilized separator sludge and contaminated debris were removed. Opal's personnel constructed a landfarm and treated oil-contaminated soils as part of the source removal.

The ground water remedy included the installation of 53 Soil Vapor Extraction / Ground Water (SVE/GW) wells in the NAPL source areas to extract, treat and reinject approximately 5,000 gallons of water per day. An estimated 54,736 gallons of NAPL was removed from three underlying fractured sandstone units along with hydrocarbon-contaminated ground water.

The subsurface system was comprised of 35 pumping wells and three air injection wells in the South NAPL Area, ten SVE/GW pumping wells and three air injection/air sparging wells in the North NAPL Area, eight SVE/GW pumping wells in Miscellaneous NAPL Areas. The treatment systems included 1) two liquid ring vacuum pumps, 2) extensive compressed air systems for pneumatic pumps, air injection and instrumentation; 3) an oil water separator, 4) an air stripping unit, 5) a Thermal Catalytic Oxidizing Unit (TOU), 6) Granulated Activated Carbon Units (GACs) for final polishing of treated ground water, 7) a shallow injection discharge system for disposal of treated water, and 8) extensive instrumentation and controls.


Type of Work: Excavation, Lead, Asbestos, Petroleum Hydrocarbons, Pump and Treat, SVE

Size: 60,000 gallons

Services: Environmental Remediation

Related Projects: Excavation and Landfill Construction, Excavation and Landfill Design/ Oversight, Excavation and Landfill Design/Build, Landfill Construction