NAPL Oil Recovery at Active Industrial Facility

At a glance

Location: New Jersey

Geology: Silty sand

Contaminant(s): Heavy petroleum, LNAPL

ETEC Solution(s): PetroSolv

Unique challenge(s): Active business, Mixed contaminant types

Site Summary

On a challenging active industrial site with two distinct areas containing diesel free-product and motor oil, we achieved goals for the site using our PetroSolv™ surfactant product. A 2-week Surfactant Injection/Extraction event was planned in a way to maximize pore volume flushes/exchanges. A total of 8,000 gallons of surfactant solution was injected, and 15,000 gallons of fluid was extracted. Three months later, no NAPL was found in either area.

Site conditions and remedial goal

This active power plant facility had 2 distinct NAPL areas. Area 1 contained ~0.5’ diesel free product, likely from overfill of adjacent generator.  Area 2 contained ~3.0’ used motor oil from used oil drum storage area. Monitoring wells and soil borings were installed in each area to delineate NAPL plume. Manual bailing and several mobile High Vacuum Recovery (HVR) events had already been applied to wells in Area 1 and Area 2, but NAPL persisted.

ETEC Solution

ETEC performed a 2-week Surfactant Injection/Extraction Event in Area 1 & Area 2.  3,000 gallons of surfactant solution was injected into Area 1, and 5,000 gallons of into Area 2. The surfactant injection was combined with simultaneous groundwater extraction from key wells continuously (8-hours a day) for 4 days to optimize in-situ contact with the NAPL-impacted smear zone. Injection or extraction was rotated between different wells to optimize subsurface surfactant contact and distribution.

Fluid recovery was performed during the second week of activities using two separate submersible extraction pump systems (6-pump controllers) supplied by ETEC. The goal was to ensure optimum recovery of injected surfactant fluid and emulsified NAPL mass. The two extraction systems maximized pore volume flushes/exchanges.  In total, 5,000 gallons of fluid was recovered from Area 1, and 10,000 gallons of fluid from Area 2.

Remedial outcome

By the end of extraction event, fuel odor had decreased dramatically, confirming contact and capture. A significant layer of NAPL was observed in the aboveground frac tank (used for temporary storage of extracted fluid), indicating successful capture of NAPL mass in Area 1 and Area 2.

When testing three months following the injection event, no NAPL was detected in Area 1 or Area 2.

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