Residential Heating Oil Tank Removals at Laurel Bay Military ...

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Residential Heating Oil Tank Removals at Laurel Bay Military ...

Residential Heating Oil Tank

Removals at

Laurel Bay Military Housing

MCAS Beaufort, South Carolina


Overview

‣ Description of Laurel Bay

‣ History of the heating oil tanks

‣ The removal process

‣ Follow up actions


Laurel Bay Military Housing

Laurel Bay military housing (LBMH) is located

approximately 3 miles west of MCAS Beaufort.

‣ LBMH was originally built in the mid 1950s. It is

approximately 1100 acres and consists mostly of

single family military housing.

‣ It is bordered on the west by tidally influenced

salt marshes and the Broad River and on the

north, east and south by forested uplands.


Heating Oil Tank History

‣ 280 gallon heating oil tanks were installed when homes

were built and can be located in the front or back of the

home depending on the design.

Tanks were installed with a concrete pad on top that can

be as much as 12 inches thick.

Tanks were last used in the early 1980s when heating

for the homes was switched to natural gas. Heating for

the homes have since been changed over to geothermal.

‣ After the switch to natural gas a project was completed

in the mid-1980s that abandoned the tanks by pumping

out the tanks and filling with sand.


Heating Oil Tank History (cont.)

‣ Over the years tanks were encountered during utility

work. These tanks were typically removed and soil

samples were collected.

‣ In the early 2000s a Public Private Venture (PPV)

managing partner took over base housing and, as part of

the contract, was responsible for removing tanks that

interfered with housing demolition and renovation

projects.

‣ PPV partner removed tanks from 6 houses and, because

they approached the removal more like a construction

project than an environmental project, a work plan was

developed for tank removals by NAVFAC SE and MCAS

Beaufort that was agreed to by State regulators and PPV

Managing Partner.


Heating Oil Tank History (cont.)

‣ As tanks were removed it was discovered that some

homes had 2, 3 and sometimes 4 tanks.

‣ One tank was typically filled with sand but the other

tanks were either empty or contained water/water fuel

mixture.

‣ Also discovered was that around 70% of the tank sites

had soil contamination above State action levels.

‣ Because of the multiple tank situation and the high

percentage of sites with elevated soil contamination,

MCAS Beaufort determined it would be best to remove

all tanks remaining after PPV partner completed their

removals.


Heating Oil Tank History (cont.)

‣ After PPV Partner removed about 136 tanks

from about 114 home sites they decided to get

out of the tank removal business.

‣ MCAS Beaufort then started to remove the

remaining tanks.

‣ Total tanks removed to date: 562 tanks from 482

houses.

‣ 615 to 719 tanks left in the ground.

‣ Percentage of sites with soil contamination

above State action levels has gone down to

about 54%.


Removal Process

‣ Standard tank

removal.

‣ Excavate enough soil

to remove tank.

‣ Remove concrete

pad, if present

‣ Remove Tank.

‣ Collect soil sample.

‣ Backfill excavation.


Removal Process (cont.)

‣ Slightly more to it due to occupied homes

and previous house renovations.

‣ Prior to 2009 nearly all tanks were

removed from homes that were

unoccupied because of demolition or

renovation.

‣ Renovations included additions, new

sidewalks/driveways, improved

landscaping and new irrigation lines.


Removal Process (cont.)

‣ Renovations resulted in some tanks

located partially or wholly beneath

porches, driveways, sidewalks, flower

beds, or new irrigation lines.

‣ In addition, there are sewer lines in front

yards but no one knows where.


Removal Process (cont.)

‣ At occupied homes the removal process is

slightly more involved.

Tank work can only be done between

0800 and 1600 Monday through Friday.

‣ Residents must be notified prior to tank

removal.

‣ Excavations cannot be left open due to

residential nature of the area.


Removal Process (cont.)

‣ Although we have original plans showing tanks

locations, a magnetometer and push probe are used

to verify tank location since some tanks are not

located where plans show them.

‣ After the tank(s) are located flower beds are

deconstructed or sod is removed.

‣ At the start of removal excavator carefully scrapes

away soil to look for sewer/irrigation lines.

‣ If sewer/irrigation line is found, it is cut and capped.

‣ Excavation then proceeds to the top of the concrete

or top of the tank.


Removal Process (cont.)

‣ If concrete is present it is removed as one piece

(if thin enough) or in pieces if it is too big or too

thick

‣ After the tank is exposed, if it is full of sand it is

removed, wrapped in plastic, and taken to a

landfill.

‣ If tank has not been abandoned, any fluid is

pumped out and properly disposed, tank is

removed, wrapped in plastic, and taken to a lay

down area to be cleaned and delivered to a

recycler.


Removal Process (cont.)

‣ After tank removal, a soil sample is collected from

beneath the fill end and analyzed for

BTEX+naphthalene, and SVOCs.

‣ Excavated soil is returned to the hole and additional

fill is placed in the excavation up to ground level.

‣ If required, sewer/irrigation lines are reconnected,

and flower beds/lawns are reconstructed.

‣ After soil sampling results are received a report is

generated using the State’s UST Closure

Assessment form and is submitted to the SCDHEC.


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Follow-up Actions

‣ For those sites where no soil contamination is detected

or is below State action levels for UST petroleum sites, a

“no further action” determination is warranted for the site.

‣ For regulated UST sites, when soil contamination

exceeds action levels, the State will typically require an

Initial Ground Water Assessment (IGA) that calls for the

installation of a permanent well. Heating Oil USTs are

not regulated, so the IGA is used as a guideline for

further investigations. For Laurel Bay, because the work

is conducted at occupied homes, a temporary well is

installed to minimize disturbance to residents.

‣ SCDHEC’s IGA form is used to report the sampling

results.


Follow-up Actions (cont.)

‣ As with the soil samples, if the ground water results are

below detection limits or action levels then a “no further

action” determination is warranted.

‣ If the ground water results are above action levels then

permanent wells are installed and sampled. Appropriate

corrective actions are then implemented for the site.

‣ At this time all Marine Corps funding received for heating

oil tank work at Laurel Bay is utilized for the removal of

the tanks since the most important aspect of this work is

tank removal. The Navy is expected to take over funding

for follow-up corrective actions in FY12 under the

Environmental Restoration, Navy program.


Lessons Learned

‣ Keep the residents happy. Let them know what

your going to do and when you will be at their

residence. Ensure proper site restoration.

‣ Utilities – Sixty-year old homes are bound to

have underground utilities that no one knows

about or where they are located.

‣ Make sure you have the State on board with

removal/corrective action methodologies.

‣ Make sure PPV partner is aware of their

responsibilities with regard to heating oil tanks.

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