WI0800219_Other Agency Documents_20110321

DIVISION OF WATER QUALITY
AQUIFER PROTECTION SECTION
August 23, 2024
PERMIT ISSUANCE MEMO
TO: Debra Watts
THROUGH: Thomas Slusser
FROM: David Goodrich
RE: Permit To Inject RegenOx and ORC-A
Marine Corps Base Camp Lejeune SWMU 350
I recommend that Permit Number WI0800219 be issued to Marine Corps Base Camp Lejeune to inject RegenOx
and ORC-A to remediate soils and groundwater contaminated with petroleum hydrocarbons and chlorinated
organic solvents.
SITE DESCRIPTION The site is flat and was occupied by six above -ground storage tanks that were installed
in 1942 and removed in 1993. It was used for fuel transfer from rail cars to tanker trucks to serve the Camp
Lejeune Military Base. It is currently a vacant field that is bounded by a highway to the north and by wooded
areas on the other three sides. There are two schools and a base housing development in the immediate area.
HYDROGEOLOGIC DESCRIPTION The site is situated in the Coastal Plain Province in a coastal area that is
characterized by unconsolidated sediments overlying the Castle Hayne formation, which is encountered at a
depth below 55 feet. The top layers of the injection areas are characterized by clay and clayey silts transitioning
to silt and silty sand, underlain by organic silty clay and poorly graded sand above the Castle Hayne formation.
Ground water is typically encountered at a depth of 4 to 8 feet below the surface of the ground, and the
horizontal hydraulic gradients indicated by wells screened in the shallow, intermediate, and deep aquifer zones
have all been less than 1% (0.01 ft/ft). Vertical hydraulic gradients are usually not a major factor in shallow,
unconfined aquifer settings, however, at this location the average downward (vertical) gradient has been shown
to be on the order of 0.056 ft/ft between the shallow aquifer zone and the intermediate aquifer zone, and 0.001
ft/ft between the intermediate aquifer zone and the deep aquifer zone. Assuming an effective porosity of 10%
and an observed horizontal gradient of 1% with a calculated hydraulic conductivity of 45 ft/day, the horizontal
groundwater velocity is approximately 4.5 feet per day.
EXTENT OF CONTAMINATION The contamination consists of petroleum hydrocarbons and chlorinated
solvents. The contaminated portion of the shallow aquifer is approximately 30 feet thick (maximum), 200 feet
wide (maximum width), and 470 feet long (maximum length, as shown on cross-section Figures 2-3 and 2-4,
and on Figure 4. It is immediately to the west of SWMU 350.
PROPOSED INJECTION The applicant proposes to use RegenOx for an initial tracer event in a single
push point to confirm groundwater flow direction and injection well radius of influence, and then at 75 injection
push points for in situ chemical oxidation at a depth interval of 20 to 35 feet in the most highly contaminated
area. This event will be followed by another injection event using ORC-A at 26 push points (13 in each of two
other areas that are downgradient) at a depth interval of 20 to 35 feet for enhanced aerobic bioremediation. The
remedial injection events (involving 101 injection push points) may be repeated after ten months, pending the
results of the initial injection effort. The total injection volume of the RegenOx solution will be 21,300 gallons
per event, and the ORC-A solution will be 858 gallons per event. Assuming that the shallow aquifer zone has an
effective porosity of 10% and an average saturated thickness of 40 feet, the injection volume total for both
injectants would occupy an aquifer volume of approximately 29,400 cubic feet, or an area of approximately 27
feet squared. The shallow aquifer has a contaminated volume estimated to be approximately 800,000 cubic feet,

and the injectant volume is approximately 4% of this.
HOW IT WORKS RegenOx is an oxidation chemical mixture consisting of a sodium percarbonate /
catalytic formulation with an activator complex that breaks down petroleum hydrocarbons and chlorinated
solvents through chemical oxidation into the end products of carbon dioxide and water. ORC-A is a formulation
of calcium oxyhydroxide and calcium hydroxide that, upon contact with water, produces a controlled release of
molecular oxygen for up to 12 months which supports naturally occurring aerobic biodegradation.
MONITORING Fifteen monitoring wells will be used to assess the effectiveness of the injection
program in the shallow, intermediate, and deep aquifer zones. The wells will be sampled prior to injection and
quarterly thereafter for VOCs by EPA Method 8260B, temperature, conductivity, ORP, pH, DO, and turbidity.
The Wilmington Regional Office concurs with the proposed monitoring plan, as does the Central Office. No
modifications are being made.
EPIDEMIOLOGY On September 5, 2007 and on August 5, 2005, the DHHS' Epidemiology Branch
provided comments on RegenOx and on ORC-Advanced for groundwater remediation activities. Dr. Luanne K.
Williams did not present any information that would preclude the use of these products for injection but did
provide a health risk analysis and worker safety precautions, which are in Part X of the attached permit.
REGIONAL OFFICE COMMENTS Charles Stehman of the Wilmington Regional Office recommends issuance
of this permit. The Regional Office staff pointed out that the site is adjacent to two schools and a large
playground and that precautions should be taken to keep curious children from entering the site during the
injection process. The staff also noted that the consultant should notify the Aquifer Protection Section five
working days prior to the injection activity to allow them the opportunity to inspect the site and observe the
activity. These are addressed in the permit.