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Scope of Services Provided:
- Remedial Investigation
- Free Product Recovery
- Vacuum Extraction
- OxyVACSM
- Groundwater Monitoring
- On-site Gas Chromatograph
- OSHA-trained Personnel
Role: Prime to Owner
Date Completed: November 1990
Hydrocarbon contamination was detected in a tract adjacent to this petroleum
refinery in September 1988. As a result of the contamination, Terra
Vac was contracted by the owner to perform a remedial investigation,
and to remediate the hydrocarbon-impacted soils. Gasoline, diesel and
jet fuel had been identified in the contaminant plume.
Terra Vac began the remedial investigation in May 1989 by installing
a total of 72 wells (a combination of groundwater monitoring and vacuum
extraction wells) within and around the refinery to determine the source
of the hydrocarbons and to delineate the extent of the subsurface hydrocarbon
plume. Additionally, Terra Vac performed aquifer testing to determine
its hydraulic characteristics.
The subsurface was characterized as a relatively homogeneous, thin,
upper layer of clayey silt and fine sandy silt, from 4 to 8 feet below
the ground surface. Beneath the upper soil layer was a lower layer of
medium-to-coarse grained sands which varied from 30 to 60 feet in thickness.
The depth to groundwater varied from 25 to 30 feet in the investigation
area.
Samples taken during the remedial investigation showed that the groundwater
and soils were impacted by hydrocarbons characterized as a mixture of
gasoline, diesel and jet fuel as well as some heavy oils. The hydrocarbon
plume in the groundwater was estimated to be one mile in length. The
lateral and vertical extent of the hydrocarbons in the soil was extensive.
The extent of the contamination was attributed to multiple sources and
the transmissivity of the groundwater aquifer. The remedial investigation
showed that the hydrocarbon concentrations were a result of transport
along the surface of the water table. The data was used to identify
several likely sources on the site.
Terra Vac installed a pilot vacuum extraction system to remove free
product, provide source control, and capture vapors prior to their release
to the atmosphere. Terra Vac also mobilized a catalytic oxidation unit
to treat all extracted vapors.
Over an operating period of 20 days, this pilot system removed over
10,000 pounds of hydrocarbons (equivalent to 1,430 gallons of gasoline)
at a flowrate of 1,000 standard cubic feet per minute. The measured
radius of influence from the extraction wells was approximately 80 feet.
Based on this initial pilot test, the system was expanded in December
1988 and again in May 1989. Remediation activities at this site continued
until November 1990 and recovered a total of 204,000 pounds of hydrocarbons
over a 25-month operating period. In addition, the presence of liquid-phase
hydrocarbons were substantially reduced.
Scope of Services Provided:
- Remedial Investigation RI/FS Report
- Feasibility Testing Design
- Vacuum Extraction
- Spray Aeration Water Treatment
- On-site Gas Chromatograph
Role: Prime to Owner
Date Completed: March 1988
The Upjohn Superfund site in Barceloneta, Puerto Rico was the first,
and as of April 1992, the only Superfund site to have soils completely
cleaned (over a 30 month period) by the vacuum extraction (VE) technology.
The contaminant removed from this site was predominantly carbon tetrachloride
(CCl4) which leaked from an underground storage tank located in an industrial
tank farm. Contamination was found as deep as 300 feet in the unsaturated
zone and had already reached the aquifer when the subsurface investigation
had begun.
The subsurface at the site consisted of a karst limestone, containing
a primary drinking water aquifer. The typical subsurface profile of
the area contained surface deposits from 40 to more than 200 feet, consisting
of residual silt and clay. Soil hydraulic conductivities ranged from
10E-5 to 10E-7 cm/sec. Beneath this formation were limestone formations
which contained the unconfined aquifer. The water table was at a depth
of 300 feet.
As groundwater recovery operations were initiated to control migration
within the aquifer, a pilot vacuum extraction system (VES) consisting
of three wells was designed and installed to determine the radius of
influence of the extraction well and to test the efficacy of the innovative
system. After seeing extraction rates of raise to 250 pounds per day,
additional wells were installed to complete the full-scale system that
was used at the site.
Terra Vac's founder, Mr. James Malot, was instrumental in the design
and implementation of the VES at this site. The full-scale system included
31 VE wells and six vacuum extraction units. The VES was capable of
up to 29.9 inches of mercury and a total of 1,000 cubic feet per mintute.
Nearly 18,000 gallons of CCl4 were recovered during the remediation.
An additional 8,000 gallons were extracted during a pilot study operated
from January 1983 to April 1984. The total volume of soil treated at
this site was over 1,000,000 cubic yards, and the VE process was credited
with remediating 90% of the original spill volume.
The site was closed in March 1988 when three months of operations occurred
with non-detect levels of CCl4 in the extracted air stream. EPA confirmed
lab results showed less than 0.01 parts per million in the soils. Initial
soil concentrations had been in excess of 2,000 ppm.
The success seen at this site and other concurrent applications resulted
in Mr. Malot and Upjohn applying for and receiving two patents for the
process of VE to remove volatile organic compounds from the subsurface.
Scope of Services Provided:
- Environmental Assessment
- Remedial Investigation
- Dual Vacuum Extraction
- Vacuum Extraction
- Tank Removal
- Source Control
- Vapor Phase Carbon
- OSHA-trained Personnel
- Groundwater Treatment
- On-site Gas Chromatograph
Role: Prime to Owner
Date Completed: February 1994
Contamination at this operating dry cleaning plant resulted from the
release of chlorinated solvents, primarily tetrachloroethylene (PCE,
PERK), to the soils under the plant. The groundwater also was impacted
by the overlying soil contamination. Site characteristics included 20
feet (6 meters) of sandy soils overlying bedrock, and groundwater was
approximately eight feet (2.4 meters) below ground surface.
The cleanup was conducted under an Interim Measure (IM) to establish
source control through the remediation of the site soils. The cleanup
goals for the soils were 500 µg/kg [parts per billion (ppb)] with groundwater
to be cleaned to 3 mg/l [parts per million (ppm)]. PCE cleanup was completed
in-situ, without excavation.
To minimize the remediation time and overall project costs, Terra Vac
implemented a phased remedial approach for the site. Terra Vac's scope
of work completed the assessment/investigation while implementing dual
vacuum extraction (DVE), a proven technology for remediating PCE-contaminated
sites. This integrated approach enabled Terra Vac to provide the most
rapid and cost effective remediation of the client's site. Terra Vac
began operations in March 1993 with the removal of a 5,000-gallon (20,000-liter)
heating oil tank. The system for the IM used five DVE wells to address
the contamination under the building. All DVE wells were placed below
grade around the perimeter of the building to minimize impacts on parking
and pedestrian traffic.
Operation of the DVE remediation system commenced in August 1993. In
the first three months of operations, 200 pounds (90 kg) of PCE were
removed. All extracted vapors were treated through the dry cleaner's
on-site activated carbon/steam regeneration facility until a decline
in the vapor-phase concentrations led to the demobilization of the vacuum
extraction equipment in December of 1993. Approximately 240 pounds (110
kg) of PCE were removed from the site. All extracted groundwater was
treated with liquid phase activated carbon prior to discharge to a storm
drain. Terra Vac continued groundwater treatment until February 1994.
Scope of Services Provided:
Role: Prime to Owner
Date Completed: Ongoing
Subsurface contamination of this former airline terminal resulted from
the release of jet fuel to the subsurface due to spills and leaks associated
with the hydrant fueling system, and to a lesser degree from underground
storage tanks containing motor fuel, heating oil and ethylene glycol.
The site is covered by 1 to 1.5 feet (30 - 45 cm) of reinforced concrete,
with the subsurface comprised of fine to medium sands and trace quantities
of silt. This stratigraphy is present at depths ranging from 11 to 14
feet (3.3 - 4.2 m) below grade and is underlain by a thin, low permeability,
clayey-peat layer. The depth to groundwater ranges from 6 to 8 feet
(1.8 - 2.4 m) below grade. Free product is also present floating on
the groundwater table.
Terra Vac is under contract to design, construct, operate and maintain
a high vacuum, dual phase extraction system (HVDPE) to address contaminated
soils and recover free product found at several locations at the site.
The project consists of two phases. Phase I required the rapid mobilization
and construction of the system to meet the owners' construction schedule.
The construction of the Phase I system is complete. Startup was in July
1994. As a result of the HVDPE system effectively dewatering the saturated
zone, Terra Vac has instituted a bioventing system [BIOVACSM] system
to address semi-volatile compounds in the subsurface.
The Phase I recovery system consists of two separate systems, including
a total of 51 HVDPE wells outfitted with jet pumps, 29 air injection
wells for groundwater sparging and/or bioventing, two 50 horsepower
(37.5 KW) high vacuum extraction units capable of 1,000 standard cubic
feet per minute (scfm) [1.650 normal cubic meters per hour] airflow,
and a vacuum extraction unit for air injection. The off-gas treatment
systems consist of a catalytic oxidation unit capable of 1,000 scfm
air flow and four 1,000-pound (300 kg) vapor phase, granulated activated
carbon canisters.
The major components of the groundwater treatment system include liquid/vapor
separators, product recovery tanks, iron oxidation tanks, inclined plane
clarifiers, sludge holding tanks, centralized groundwater recovery equalization
tanks, a 100 gpm (23 m3/h) air stripper and six 1,000-pound (300 m)
liquid phase granulated activated carbon canisters.
A data acquisition system is also on-line to monitor the vacuum, air
flow, pressure (pumps) and levels of sludge and/or free product. The
data acquisition system also notifies Terra Vac in the event of a system
or component shutdown or malfunction.
The Phase II system, which is currently under design, will be comparable
in size to the Phase I system. The Phase II system will be constructed
after contractors complete the demolition of the terminal building.
The construction of the Phase II system is currently scheduled to commence
in the Spring of 1995.
Scope of Services Provided:
Role: Prime Contractor to Seller
Contamination Type: Gasoline
Date Completed: July, 1994
Terra VacÕs remediation system was designed for removal of gasoline
from soil and ground water beneath a vacant gas station during construction
of a new commercial building at the site. All subsurface piping and
well head locations wer precisely surveyed and placed >4 feet deep
to prevent interference with future building foundations, footings,
etc. Once building construction began, direct access to well heads was
prohibited, consequently, remote well heads and manifold systems were
designed for individual well head control and monitoring from a point
outside of the building footprint.
Terra VacÕs proprietary automatic entrainment devices, designed for
maintenance-free extraction of gasoline contaminated vapors and ground
water, were installed in 21 Dual Vacuum Extraction (DVE) wells located
beneath the building footprint. A second well casing was additionally
installed in three DVE wells for extraction of shallow soil vapor contaminants.
Remediation system components included a 40 horsepower vacuum extraction
unit capable of 500 SCFM air flow; a 200 gallon vapor/liquid separator
equipped with an internal air sparging device; and a 200 pound liquid
phase carbon bed capable of up to 10 gallons per minute of water flow.
As water quality levels prior to the carbon polish system never exceeded
discharge requirements, the carbon polish system was taken off-line
after three months of operations. Contaminant recovery was conducted
at an average well head vacuum of 5 inches of mercury and an averge
airflow of 20-40 standard cubic feet per minute per DVE well. Above
ground components of the water treatment system were equipped with tank
heater, heat tape, and pipe insulation to prevent freezing during winter
operations.
During five months of remediation system operation, approximately 5,000
lbs of gasoline were extracted. One well containing free product was
reduced to a ground water concentration of 36 ug/L of benzene in just
21 days. In spite of intermittent down time due to system damage by
the building construction contractor, the auto entrainment devices operated
flawlessly. Regulatory site closure is pending based on a year of ground
water monitoring.
Scope of Services Provided:
- Ground Water Pump Tests
- Activated Carbon System
- Design of Ex situ Treatment Cells/Liners
- Soil Gas Surveys
- OxyVACSM
- Vacuum Extraction
- Dual Vacuum Extraction
- Ground Water Monitoring System
- Underground Well Installation
- Integrated Ground Water Extraction and Treatment Systems
- On-site Process Control
- OSHA Trained Personnel
Role: Prime Contractor to Owner
Date Started: February 1990
Between September 1988 and February 1990, Terra Vac was contracted to
test the efficacy of the dual vacuum extraction process in cleaning
waste yard soils containing high levels of chlorinated VOCs. The area
was being considered for commercial development and required immediate
attention under a tight schedule.
The soils at the site were highly heterogeneous, consisting predominantly
of clays and chemical wastes resembling chalk deposits (e.g., calcium
carbonates, oxides and sulfates), Permeabilities ranged from 10E-4 to
10E-8 cm/sec. Contaminants included TCE, tetrachloroethane, methylene
chloride and vinyl chloride.
A short, one-week pilot program was conducted and consisted of five
DVE wells and the associated activated carbon water treatment systems.
This pilot was immediately expanded to evaluate ex situ vacuum extraction
of stockpiled soils in cells designed by Terra Vac, and variations of
ground water extraction integrated with DVE. The integrated system consisted
of horizontal subsurface recovery networks as well as a wellpoint recovery
network. Operation of the ground water treatment system was also significantly
upgraded to treat up to 60 gpm of influent.
While several systems of varying size were installed and operated during
the course of the three-month operating period, ultimately, three main
vacuum extraction systems were designed, constructed and operated by
Terra Vac: one for the treatment of excavated and stockpiled soils for
ex situ treatment, one for the DVE wells and dewatering wellpoints,
and one for a horizontal DVE trench recovery network. This network consisted
of 15 trenches ranging from 200 to 4,000 feet in length.
The full-scale vacuum extraction system consisted of 12 vacuum extraction
units operating at a design flow rate of 3,000 SCFM at 14" Hg and
achieved extraction rates of up to 400 pounds per day. Extracted vapors
were primarily treated with a multiple stage activated carbon system,
but was complemented late in the project by a catalytic oxidation unit.
In a three-month operating period, approximately 9,000 pounds of chlorinated
VOCs were extracted and treated, representing an 80 percent reduction
in the soil concentrations. An additional 1.5 million gallons of ground
water were treated, resulting in removal of approximately 750 pounds
of VOCs from the aqueous phase. After this operating period, the soils
were determined to be treated to acceptable risk levels. This resulted
in the NYSDEC approving the excavation of the soils to allow for the
construction of the foundation for a shopping center.
Scope of Services Provided:
Role: Prime Contractor to Client
Date Started: April 1992
Terra Vac is providing the client with remedial services to clean-up
their San Jose site impacted with SHELLSOL, NAPHTHA and Freon. The site
consists of a complex lithological setting soil and groundwater impacted
with semi-volatile organic compounds and solvents.
The remedial system incorporates pneumatic soil fracturing, hot air
injection, Dual Vacuum Extraction and vapor extraction technologies.
The remedial system includes, 3-40 Hp vacuum extraction blowers, 30
VE wells, 40 Dual Vacuum Extraction wells and 20 Hot Air Injection wells.
The injected air stream will be heated to 650 degrees Fahrenheit by
electric heater banks. These innovative technologies have increased
contaminant mass extraction rates by more than 10-fold.
Scope of Services Provided:
Role: Subcontractor to A/E firm
Date Started: January 1993
Terra Vac's Western Region is currently involved in the cleanup of a
large chlorinated plume under an aerospace facility in California. The
site has a complex lithology (heterogeneous soils, perched water, etc.)
with contamination as deep as 120 feet. Additional constraints include
the location of the chemical plume under two buildings that required
the installation of all wells below grade.
A pilot soil vacuum extraction project was completed in September 1991
and consisted of 11 wells within four borings at the site. Terra Vac
has recovered over 20,000 pounds of vapor phase chlorinated organic
compounds over the one-year operating period.
Based on the success seen during the pilot a total of 120 wells have
been constructed within 50 borings at the site. The complexity of the
lithology will required up to three wells per boring. All extracted
vapors will be treated with an activated carbon system prior to discharge.
To date 3,000 pounds of vapor-phase chlorinated organic compounds have
been removed.
Scope of Services Provided:
- Vacuum Extraction
- Vapor Phase Carbon
- On-site Gas Chromatograph
- On-site Laboratory
- OSHA-trained Personnel
Role: Prime to Owner
Date Completed: August 1991
During demolition activities in 1988, chlorinated hydrocarbon contamination
was discovered in the soils at this former dry cleaning facility. A
subsequent site investigation confirmed the presence of chlorinated
hydrocarbons in both the subsurface soils and the groundwater. Further
investigation to delineate the plume also identified the presence of
petroleum hydrocarbons.
Based upon the site assessment reports, Terra Vac designed a two-phase
vacuum extraction system (VES). Phase I, a pilot to demonstrate the
feasibility of the technology, consisted of three vacuum extraction
(VE) wells, a vacuum extraction unit, a vapor/liquid separator and two
1,000-pound vapor carbon treatment units. This design took advantage
of the depressed water table caused by California Department of Transportation's
dewatering system. Phase II, implemented upon approval of Phase I results,
expanded the system to full-scale with the addition of four wells.
The system operated from April 1991 through August 1991, removing approximately
1,200 pounds of both petroleum and chlorinated hydrocarbons. The extracted
vapor concentrations were reduced 90 to 99% from initial levels.
Laboratory analyses of soil samples taken from confirmatory borings
showed the effective remediation of the soils. Tetrachloroethylene (PCE)
was reduced to levels of 0.26 parts per million (ppm) or less in the
soil. All final borings showed either no detectable levels of aromatic
hydrocarbons or amounts far below Santa Barbara County LUFT Program
cleanup levels. Only one sample showed a total petroleum hydrocarbons
value slightly higher than the 100 ppm target (120 ppm).
Scope of Services Provided:
Role: Prime to Owner
Date Completed: Ongoing
Terra Vac is operating under contract from a major petroleum distribution
company to design, install and operate a vacuum extraction system to
remediate soils and groundwater impacted by petroleum hydrocarbons,
principally diesel and gasoline. The contamination occurs over a 58,000
square foot area at this site. Groundwater with free product is found
at 15 feet below ground surface. The soils at the site have permeabilities
as low as 1 x 10-6 cm/sec and consist of saprolites.
Prior to initiating the construction at the site, Terra Vac performed
groundwater modeling to determine the design parameters for the full-scale
system. A Corrective Action Plan was also devised and submitted to the
State Regulatory Agency for approval.
The remedial system consists of 19 dual vacuum extraction (DVE) wells,
a 40 horsepower vacuum extraction unit capable of 15 inches of mercury
at 750 standard cubic feet/minute (scfm) airflow, a catalytic oxidation
unit capable of handling 1,000 scfm airflow, and a groundwater treatment
system consisting of an oil/water separator with a shallow tray air
stripper capable of treating 20 gallons per minute followed by polishing
with liquid phase activated carbon.
Terra Vac completed installation and start-up of the full-scale system
in October 1994. Initial vapor-phase VOC extraction rates were as great
as 900 pounds per day. Over 80 gallons of liquid-phase petroleum product
were recovered during the first week of operations. By the end of December
1994, Terra Vac had removed over 32,000 pounds (approximately 5,000
gallons) of VOCs with the DVE system. Operations are continuing in 1995.
Scope of Services Provided:
Role: Subcontractor to Client
Date Completed: Ongoing
Terra Vac is operatin a full scale vapor extraction and bioventing system
at a former firefighting training area (Burn Pit) at Marshall Army Airfield.
The site was once used to train military personnel in fighting a variety
of fires. This included fixed wing and rotary wing aircraft. The types
of fuels used at this location were JP-4, AVGAS, and MOGAS. The mixture
of fuels used for fire training have resulted in contamination of soils
by several volatile organic compounds (VOCs). The list includes benzene,
toluene, ethyl-benzene, xylenes, and solvents such as PCE, TCE, TCA,
DCA and methyl ethyl ketone (MEK). The site soil is a silty clay.
The remediation system includes a network of soil vacuum extraction
wells, separate piping manifold systems, air/water separators, a 10
hp vacuum extraction blower and vapor phase granulated carbon adsorption
vessels.
The bioventing system consists of sparge and vapor extraction wells.
An air compressor injects air into the subsurface. The sparge well is
surrounded by a series of vacuum wells which removes vapors to the carbon
treatment vessels.
Carbon inlet concentrations for this system in the first 26 days of
operation were between 1,300 and 1,800 ug/l. The system initially generated
approximately 14 pounds of VOCs per day. The bioventing system is averaging
900 to 1,100 pounds of VOCs per day.
Scope of Services Provided:
Role: Prime to Owner
Date Completed: Ongoing
Terra Vac was selected in early 1992 as the Emergency Response Contractor
to manage the remediation of soils and groundwater contaminated with
gasoline from a ruptured pipeline. The contamination occurred over a
2 acre area, and required the rapid mobilization of equipment and resources
to provide source control at the impacted area. Remedial investigation
and groundwater monitoring is being performed in conjunction with the
remedial action. Terra Vac also prepared and submitted the necessary
documents for the approval of the remedial action plan currently underway
at the site.
The remedial system at the site currently consists of 23 vertical dual
vacuum extraction (DVE) wells, eight horizontal soil vacuum extraction
(SVE) trenches and two groundwater extraction wells. Extracted groundwater
is being transferred to an oil/water separator for free product recovery
prior to its transfer to an air stripper. Extracted vapors are treated
by a catalytic oxidation unit capable of treating 1,000 standard cubic
feet per minute.
During the 24-month operating period, Terra Vac has extracted and treated
over 11 million gallons of groundwater, from which 1,000 gallons of
free product have been recovered. Additionally, over 17,000 pounds of
vapor-phase product have been recovered.
This phased remedial approach, i.e., construction concurrent with investigation,
is critical to the rapid and cost effective cleanup of sites under an
emergency situation.
This page and contents © Copyright 2001 by Terra Vac Corporation. ALL
RIGHTS RESERVED
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