Nanoscale Zero-Valent Iron Technology for Source Remediation

Site Name:

Hunters Point Shipyard, Naval Air Station Jacksonville, and Naval Air Engineering Station Lakehurst

Location:

Hunters Point Shipyard: San Francisco, California;
Naval Air Station Jacksonville: Jacksonville, Florida;
Naval Air Engineering Station Lakehurst: Lakehurst, New Jersey

Period of
Operation:

Not Documented

Cleanup
Type:

Field Demonstration

Technology:
Hunter Point Shipyard
-- Two zero-valent iron (ZVI) injection studies were conducted, one in the source area and the other in the groundwater plume.
-- In the first study, 16,000 lbs of micron-sized ZVI powder was mixed with tap water to produce an iron slurry (265 grams per Liter [g/L]). The iron slurry was then injected into the dense non-aqueous phase liquid (DNAPL) source zone by pneumatic fracturing, using nitrogen as the carrier gas.
-- In the second study, 72,650 lbs of microscale ZVI was made into a 300 g/L slurry with tap water and was injected into a region of less contamination next to the DNAPL source using pneumatic fracturing.

Naval Air Station Jacksonville
-- 300 lbs of bimetallic nanoscale particles (BNP) was mixed with water drawn from an extraction well to produce an iron slurry (4.5 to 10 g/L).
-- The slurry was injected into the subsurface by a combination of direct push and closed-loop recirculation wells.
-- Injection was conducted first at 10 "hot spot” locations and the recirculation wells were used to distribute the slurry to the rest of the suspected source zone.

Naval Air Engineering Station Lakehurst
-- 300 lbs of BNP was mixed with water drawn from an extraction well and from a fire hydrant to produce a dilute iron slurry (2 g/L).
-- The slurry was injected in to the subsurface using direct push technology.
-- Injections were done at 10 “hot spot” locations in the Northern Plume and at five locations in the Southern Plume.

Cleanup Authority:
-- Hunter Point Shipyard: Navy
-- Naval Air Station Jacksonville: CERCLA
-- Naval Air Engineering Station Lakehurst: Navy

Contacts:
Not Documented

Contaminants:
Hunters Pont Shipyard
First study (source area, groundwater):
-- Volatiles-Halogenated: TCE (88,000 µg/L, maximum); PCE; cis-1,2-DCE; vinyl chloride; total chlorinated ethenes; chloroform; and carbon tetrachloride.

Second study (downgradient area, groundwater):
-- Volatiles-Halogenated: TCE; cis-1,2-DCE; vinyl chloride.

Naval Air Station Jacksonville
Soil:
-- Volatiles-Halogenated: 1,1,1-TCA (25,300 µg/kg, maximum); PCE (4,360 µg/kg, maximum); and TCE (60,100 µg/kg, maximum).

Groundwater:
-- Volatiles-Halogenated: PCE (173 µg/L, maximum); TCE (5,520 µg/L, maximum); and cis-1,2-DCE (1,350 µg/L, maximum).

Naval Air Engineering Station Lakehurst:
Groundwater:
-- Volatiles-Halogenated: PCE; TCE; 1,1,1-TCA; cis-DCE; and vinyl chloride.

Waste Source:
-- Hunters Point Shipyard: Leakage from an underground storage tank (UST) and the associated floor drain and underground piping; a grease trap and associated cleanout and underground piping; and five steel dip tanks from a former paint shop.
-- Naval Air Station Jacksonville: Leakage from two USTs.
-- Naval Air Engineering Station Lakehurst: Not provided.

Type/Quantity of Media Treated:
-- Hunters Point Shipyard: First study, treatment zone covered an area of 1,818 ft². Second study, treatment zoned covered an area of approximately 8,700 ft².
-- Naval Air Station Jacksonville: Groundwater (Quantity not provided).
-- Naval Air Engineering Station Lakehurst: Northern groundwater plume — approximately 8,470 ft²; Southern groundwater plume — approximately 4,350 ft².

Purpose/Significance of Application:
A field demonstration of various NZVI technologies was conducted to determine their effectiveness in treating source areas contaminated primarily with TCE, PCE, DCE, and vinyl chloride.

Regulatory Requirements/Cleanup Goals:
-- Hunters Point Shipyard: Not provided.
-- Naval Air Station Jacksonville: Reduce the total site contaminated mass by 40 to 50%.
-- Naval Air Engineering Station Lakehurst: Not provided.

Results:
Hunters Point Shipyard:
First study:
-- TCE levels declined sharply in all monitoring wells in the treatment zone without any significant formation of cis-1,2-DCE and vinyl chloride.
-- Sharp declines in oxygen-release potential (ORP) and noticeable increases in pH supported the contention that strongly reducing condition suitable for abiotic reduction of CVOCs was created.
-- Pneumatic fracturing combined with liquid atomization injection of the ZVI slurry was successful in distributing ZVI through most of the target treatment zone.
-- Injecting at shallow depths may lead to nitrogen and slurry seeping up to the ground surface.

Second study:
-- TCE and DCE were reduced rapidly in the treatment zone wells.

Naval Air Station Jacksonville:
-- Within five weeks after injection, concentrations of parent VOCs were reduced by 65 to 99%.
-- ORP reduction was experienced in most of the source zone monitoring wells, indicating that the direct push and recirculation methods of injection worked relatively well.
-- The injection did not create the strongly reducing conditions necessary to generate substantial abiotic degradation of TCE.

Naval Air Engineering Station Lakehurst:
-- TCE and PCE concentrations were reduced on average by 79% and 83%, respectively.
-- The average decrease in total VOC concentrations was 74%.
-- Monitoring data was unable to determine what caused reductions in the CVOC concentrations.

Cost Factors:
Hunters Point Shipyard:
-- Total cost for the first study was $289,300. This included costs for mobilization, equipment and supplies (ZVI cost $32,500), labor, drilling services, sampling and analysis including waste disposal, and other miscellaneous costs.
-- For the second study the total cost was $1,390,000. This included $770,000 for materials, equipment, field labor for the injection, and waste characterization and disposal; $452,000 for baseline and post-injection groundwater sampling and analysis; and $168,000 for project management, data management, and reporting.

Naval Air Station Jacksonville:
-- The approximate total cost reported for the field demonstration was $259,000 with an additional $153,000 for administrative tasks such as project management, work plan development, and a bench scale study. The field demonstration total cost included cost from mobilization, monitoring well installation, injection/circulation events (NZVI cost $37,000), sampling and analysis as well as waste disposal, and other miscellaneous costs.

Naval Air Engineering Station Lakehurst:
-- The approximate total cost reported for the field demonstration was $255,500 which included monitoring well installation, baseline sampling, nanoscale iron injection, six-month post injection sampling, and reporting results.

Description:
Hunters Point Shipyard:
Hunters Point is situated on a long promontory located in the southeastern portion of San Francisco County and extends eastward into the San Francisco Bay. From 1869 through 1986, it operated as a ship repair, maintenance, and commercial facility. In 1991, the Navy designated Hunters Point for closure under the federal Base Closure and Realignment Act. Hunters Point was divided into six separate geographic parcels (Parcels A through F) to facilitate the closure process. The first and second ZVI demonstrations were performed at Site RU-C4 in Parcel C, which is located in the eastern portion of Hunters Point. The groundwater plume at Site RU-C4 had been contaminated with chlorinated solvents, primarily TCE.

The first ZVI injection was conducted in the source area of the contamination. The treatment zone covered an area of 1,818 ft². The total cost of the first study was $289,300. The second ZVI injection was conducted in the groundwater plume. The approximate treatment area was 8,700 ft². The total cost for the second injection project was $1,390,000.

Naval Air Station Jacksonville:
Naval Air Station (NAS) Jacksonville is located in Duval County, Florida and has been used for Navy operations since 1940. The demonstration site, H1K, was located in the interior portion of the facility and contained two USTs. The USTs previously received waste solvents and other substances from a wash rack, manhole and other operations. The tanks and associated pipelines were removed and capped in 1994. Cleanup of H1K is managed under CERCLA, and the groundwater monitoring program is managed under RCRA.

In 2000 and 2001, an Interim Remedial Action consisting of chemical oxidation was conducted in the source area. In March 2002, a site characterization sampling effort was performed to redefine the extent of contamination. The horizontal extent of contamination is approximately 1,450 ft² with a thickness of 18 ft (saturated zone), resulting in a total volume of 967 cubic yards of soil.

Iron slurry was injected into the subsurface by a combination of direct push and closed-loop recirculation wells. Within five weeks after injection, concentrations of parent VOCs were reduced by 65 to 99%. The approximate total cost reported for the field demonstration was $259,000, with an additional $153,000 for administrative tasks.

Naval Air Engineering Station Lakehurst:
Naval Air Engineering Station Lakehurst is located in Jackson and Manchester Townships, Ocean County, New Jersey, 14 miles inland from the Atlantic Ocean. The facility covers 7,383 acres and is within the Pinelands National Reserve.

The demonstration project involved two areas with the highest groundwater contaminant concentrations within the northern plume and the southern plume, Areas I and J. The contamination vertically extends 70 ft below the groundwater table. The largest amount of contamination is located in the zone from 45 to 60 ft below the groundwater table.

A bench-scale treatability study in 2001 and a pilot test study in 2003 were performed at the facility to evaluate the feasibility of using BNP as an in situ remediation technology to reduce or eliminate the contaminants at Areas I and J. This preliminary testing showed that BNP had the potential to perform better than NZVI without any catalyst coating. 10 injections of BNP were conducted in the northern plume and five injections were conducted in the southern plume. The approximate total cost for the field demonstration was $255,500.