&EPA
United States
Environmental Protection
Agency
Office of
Research and Development
Cincinnati, OH 45268
EPA/540/R-95/500a
July 1995
SITE Technology Capsule
Unterdruck-Verdampfer- Brunnen
Technology (UVB)
Vacuum Vaporizing Well
Introduction
In 1980, the U.S. Congress passed tie Comprehensive
Environmental Response, Compensation, and Liability Act
(CERCLA), also known as Superfund, committed to
protecting human health and the environment from
uncontrolled hazardous wastes sites. CERCLA was
amended by the Superfund Amendments and
Reauthorization Act (SARA) in 1986 - amendments that
emphasize the achievement of long term effectiveness
and permanence of remedies at Superfund sites. SARA
mandates implementing permanent solutions and using
alternative treatment technologies or resource recovery
technologies, to the maximum extent possible, to clean
up hazardous waste sites.
State and federal agencies, as well as private parties,
are now exploring a growing number of innovative
technologies for treating hazardous wastes. The sites on
the National Priorities List total more than 1,200 and
comprise a broad spectrum of physical, chemical, and
environmental conditions requiring varying types of
remediation. The U.S. Environmental Protection Agency
(EPA) has focused on policy, technical, and informational
issues related to exploring and applying new remediation
technologies applicable to Superfund sites. One such
initiative is EPA's Superfund Innovative Technology
Evaluation (SITE) program, which was established to
accelerate development, demonstration, and use of
innovative technologies for site cleanups. EPA SITE
Technology Capsules summarize the latest information
available on selected innovative treatment and site
remediation technologies and related issues. These
capsules are designed to help EPA remedial project
managers, EPA on-scene coordinators, contractors, and
other site cleanup managers understand the types of data
needed to effectively evaluate a technology's applicability
for cleaning up Superfund sites.
This capsule provides information on the Unterdruck-
Verdampfer-Brunnen (UVB) in situ groundwater
remediation technology, a technology developed to remove
volatile organic compounds (VOCs) from groundwater. The
UVB system is a patented technology. The developer
and patent holder is IEG mbH of Germany, and the United
States license holder is IEG™ Technologies Corporation
(IEG). The UVB process was evaluated under EPA's SITE
program between April 1993 and May 1994 at Site 31,
March Air Force Base (AFB) California, where groundwater
was contaminated with solvents, including
trichloroethylene (TCE). Information in this capsule
emphasizes specific site characteristics and results of
the SITE field demonstration at March AFB. Results
obtained independently by the developer at other sites in
the United States and Germany are summarized in the
Technology Status section. This capsule presents the
following information:
• Abstract
• Technology description
• Technology applicability
SUPERFUND INNOVATIVE
TECHNOLOGY EVALUATION
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• Technology limitations
• Process residuals
• Site requirements
• Performance data
• Technology status
Sources of further information
Abstract
The UVB technology is an in situ groundwater remediation
technology for aquifers contaminated with compounds
amenable to air stripping, and is an alternative method to
pump-and-treat remediation of groundwater. The UVB
technology is designed to remove VOCs from groundwater
by transferring the contaminants from the aqueous phase
to the gaseous phase and subsequently treating the
resulting air stream through carbon adsorption units.
The developer and patent holder is IEG mbH of Germany,
the U.S. license holder is IEG® Technologies Corporation.
The UVB system consists of a single well with two
hydraulically separated screened intervals installed within
a single permeable zone. Pumping in the lower section
followed by in situ air stripping and reinfiltration in the
upper section creates a recirculation pattern of groundwater
in the surrounding aquifer. The continuous flushing of the
saturated zone with recirculated treated water facilitates
the partitioning of adsorbed, absorbed, and free liquid
contaminants to the dissolved phase through increased
dissolution, diffusion, and desorption. Increased
partitioning through these processes is driven by increased
groundwater flow rates within the system's radius of
circulation cell and increased concentration gradient
established by the reinfiltration and recircuiation of treated
water in the aquifer.
Where applicable, the UVB technology provides an
effective long-term solution to aquifer remediation by
removing contaminants in the saturated zone without
extracting groundwater, lowering the groundwater table,
and generating wastewater typical of pump and treat
systems. Additionally, once the UVB treatment system
is installed and balanced, it requires minimal support from
on-site personnel. The UVB technology was evaluated
under the SITE program at Site 31, March AFB, where
groundwater was contaminated with solvents including
TCE.
The demonstration evaluated the reduction of TCE
concentrations in the groundwater discharged from the
treatment system, the radius of circulation cell of the
system, and the reduction of TCE concentrations in the
groundwater within the system's radius of circulation cell.
The study results showed that the UVB system removed
TCE from the groundwater by an average of greater than
94 percent. The mean TCE concentration in water
discharged from the system was approximately 3
micrograms per liter (/L/g/L) with the 95 percent upper
confidence limit calculated to be approximately 6 /L/g/L.
The study also indicated that the radius of circulation cell
was 40 feet in the downgradient direction and may extend
as far as 83 feet based on modeling of the radius of
circulation cell in the alluvial aquifer at March AFB by the
developer. The radius of circulation cell is largely
controlled by the hydrogeologic characteristics of the
aquifer and, to a lesser extent, UVB system design. TCE
concentrations within the aquifer were reduced laterally
by approximately 52 percent in the radius of circulation
cell during the 12-month pilot study.
Technology Description
One of the UVB technology designs is an in situ
groundwater remediation technology that combines air-
lift pumping and air stripping to remove VOCs from
groundwater. A properly installed UVB system consists
of a single well with two hydraulically separated screened
intervals installed within a single permeable zone
(Figures 1, 2 and 3). The air-lift pumping occurs in
response to negative pressure introduced at the wellhead
by a blower. This blower creates a vacuum that draws
water into the well through the lower screened portion of
the well. Simultaneously, air stripping occurs as ambient
air (also flowing in response to the vacuum) is introduced
through a sieve plate located within the upper screened
section of the well, causing air bubbles to form in the
water pulled into the well. The rising air bubbles provide
the air-lift pump effect that moves water toward the top of
the well and draws water into the lower screened section
of the well. This pumping effect is supplemented by a
submersible pump that ensures that water flows from
bottom to top in the well. As the air bubbles rise through
the water column, volatile compounds are transferred from
the aqueous to the gaseous phase. The rising air transports
volatile compounds to the top of the well casing, where
they are removed by the blower. The blower effluent is
treated before discharge using a carbon adsorption unit.
The transfer of volatile compounds is further enhanced
by a stripping reactor located immediately above the sieve
plate. The stripping reactor consists of a fluted and
channelized column that facilitates the transfer of volatile
compounds to the gas phase by increasing the contact
time between the two phases and by minimizing the
coalescence of air bubbles. The overall stripping zone of
the UVB system extends from the sieve plate to the top
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Carbon Adsorption Units
Blower
Well
Centerline
K-
Monitoring Well
Ambient Air
40 Feet-X
60 Feet-X
Monitoring Well
Inner Cluster
Monitoring Wells
Vapor Monitoring Well
85 Feet-X
Outer Cluster
Monitoring Wells
Groundwater
Intake
Groundwater
Table
T
Saturated Zone
CONCEPTUAL DIAGRAM
—». Groundwater flow
NOT TO SCALE
Figure 1: The Unterdruck-Verdampfer-Brunnen Well
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Fresh Air Intake
To Blower -L.
Ground Surface
inch
Monitoring Weils (W2 & W3)
with Stainless Steei Screen
(40 ft to 55 ft)
1 PVC 2 inch Deep
Monitoring Weil (W1)
with Stainless Steel Screen
(69.7 ft to 79.7 ft)
Unsaturcted
Zone
\ Vacuum
. . \Extraction
Approximate X,
Groundwater Level %>>
3 Double—cosed Screens
and 1 Bridge-Slot Screen
(41.2 ft to 55 ft) ^<
Saturated
Zone
Steel Casing
(55 ft to 69.7 ft)
3 Bridge-Slot Screens
(69.7 ft to 81.7 ft)
Sump
(81.7 ft to 83.7 ft)
24 In. Diameter
Figure 2: The As-Built Unterdruck-Verdampter-Bmnnen Configuration
NOT TO SCALE
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Frash Air Intake
To Blower '
Internal Cantrailzers
Double-Wai!
Stripper Reactor
Pinhoie Plate
Pump
Packer
Water Intake
HOPE - High Density Polyethylene
NOT TO SCALE
Figure 3: The As-Built Unterdruck-Vardampfer-Brunnen Internal Components
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of the water column. To maximize volatilization in the
stripping zone, the sieve plate and stripping reactor are
positioned at a depth that optimizes the reach of the
stripping zone and the volume of air flow into the system.
The down-well components of the UVB system have been
designed with leveling ballast that allows the system to
be free floating. This feature allows the system to
compensate for fluctuations in groundwater elevation
during operation and, thereby, maintain maximum
volatilization.
Once the upward stream of water leaves the stripping
reactor, the water falls back through the well casing and
returns to the aquifer through the upper well screen. This
return flow to the aquifer, coupled with inflow at the well
bottom, circulates groundwater around the UVB well. The
extent of the circulation pattern is known as the radius of
circulation cell, which determines the volume of water
affected by the UVB system.
The radius of circulation cell and the shape of the circulation
pattern are directly related to the properties of the aquifer.
The circulation pattern is further modified by natural
groundwater flow that skews the pattern in the
downgradient direction. Numerical simulations of the UVB
operation indicates that the radius of circulation cell is
largely controlled by anisotropy (horizontal [Kh] and vertical
[Kv] hydraulic conductivity), heterogeneity, aquifer
thickness and, to a lesser extent, well design. In general,
changes that favor horizontal flow over vertical flow such
as a small ratio of screen length to aquifer thickness,
anisotropy, horizontal heterogeneities such as low
permeability layers, or increased aquifer thickness will
increase the radius of circulation cell. As a general rule,
the developer estimates the system's radius of circulation
cell to be approximately 2.5 times the distance between
the upper and lower screen intervals.
Groundwater within the radius of circulation cell includes
both treated and untreated water. A portion of the treated
water discharged to the upper screen is recaptured within
the circulation cell. Treated water not captured by the
system leaves the circulation cell in the downgradient
direction. The percentage of treated water recycled within
the UVB system (IEG estimates that it can be up to 90
percent) is related to the radius of circulation cell and is a
function of the ratio of Kh/Kv. The larger the radius of
circulation cell and the larger the Kh to Kv ratio values,
the smaller the percentage of recycled water for a given
aquifer. The recycled treated water dilutes influent
contaminant concentrations.
Technology Applicability
The UVB technology's applicability was evaluated based
on the nine criteria used for decision making in the
Superfund feasibility study process. Results of the
evaluation are summarized in Table 1. In general, the UVB
technology is applicable for treatment of dissolved phase
volatile compounds in groundwater. The developer claims
that other UVB system configurations allow for treatment
of semi- and non-volatile contaminants and nitrates. In
addition, the chemical and physical dynamics established
by the recirculation of treated water make this technology
suited for remediation of contaminant source areas. The
technology employs readily available equipment and
materials and the material handling requirements and site
support requirements are minimal.
The UVB system demonstrated for the SITE program was
designed to remove VOCs from the groundwater, in
particular TCE and 1,1-dichloroethene (DCE). The
developer claims that the technology can also clean up
aquifers contaminated with other organic compounds,
including volatile and semivolatile hydrocarbons.
According to the developer, the UVB technology in some
cases is also capable of simultaneous recovery of soil
gas from the vadose zone and treatment of contaminated
groundwater from the aquifer as a result of the in situ
vacuum. For soil gas recovery, the upper screened portion
of the UVB well is completed from below the water table
to above the capillary zone. Although the developer claims
that the UVB technology reduces VOCs from soil gas in
the vadose zone, the technology was evaluated only for
its effects in the saturated zone.
Technology Limitations
The UVB technology has limitations in areas with very
shallow groundwater (less than 5 ft.). In such areas, it
may be difficult to establish a stripping zone long enough
to remove contaminants from the aqueous phase. The
technology has further limitations in thin aquifers (less
than 10 ft.); the saturated zone must be of sufficient
thickness to allow proper installation of the system. In
addition, the thickness of the saturated zone affects the
radius of circulation cell; the smaller the aquifer
thicknesses, the smaller the radius of circulation cell.
The majority of water being drawn from the aquifer into
the lower screen section is treated water reinf iltrated from
the upper section. This recirculation of cleaned water
significantly decreases the contaminant levels in the water
treated by the system. As the UVB system continues to
operate, the circulation cell grows until a steady state is
reached. As the circulation cell grows, the amount of
recirculated water increases causing a further decrease
of contaminant levels in the water treated by the system.
High concentrations of volatile compounds may require
more than one pass through the system to achieve
remediation goals. This may initially be a problem since
a portion of the treated water is not captured by the system
and leaves the circulation cell in the downgradient direction.
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Table 1: Feasibility Study Evaluation Criteria for the UVB Technology
CRITERION
UVB TECHNOLOGY PERFORMANCE
Overall Protection of The technology eliminates contaminants in groundwater and prevents further
Human Health and the migration of those contaminants with minimal exposure to on-site workers and
Environment the community. Air emissions are reduced by using carbon adsorption units.
Compliance with
Federal ARARs
Long-Term
Effectiveness and
Permanence
Reduction of Toxicity,
Mobility, or Volume
Through Treatment
Compliance with chemical-, location-, and action-specific ARARs must be
determined on a site-specific basis. Compliance with chemical-specific ARARs
depends on (1) treatment efficiency of the UVB system, (2) influent
contaminant concentrations, and (3) the amount of treated groundwater
recirculated within the system.
Contaminants are permanently removed from the groundwater. Treatment
residuals (for example, activated carbon) require proper off-site treatment and
disposal.
Contaminant mobility is initially increased, which facilitates the long-term
remediation of the groundwater within the system's radius of influence. The
movement of contaminants toward the UVB system within the system's
capture zone prevents further migration of those contaminants and ultimately
reduces the volume of contaminants in the groundwater.
5 Short-Term
Effectiveness
6 Implementability
During site preparation and installation of the treatment system, no adverse
impacts to the community, workers, or the environment are anticipated.
Short-term risks to workers, the community, and the environment are
presented by increased mobility of contaminants during the initial start-up
phase of the system and from the system's air stream. Adverse impacts from
the air stream are mitigated by passing the emissions through carbon
adsorption units before discharge to the ambient air. The time requirements for
treatment using the UVB system depends on site conditions and may require
several years.
The site must be accessible to large trucks. The entire system requires about
100-700 square feet (average 300). Services and supplies required include a
drill rig, off-gas treatment system, laboratory analysis, and electrical utilities.
7 Cost
Capital costs for installation of a single unit are estimated to be $180,000, and
annual operation and maintenance costs estimated to be $72,000.
8 Community
Acceptance
The small risks presented to the community along with the permanent removal
of the contaminants make public acceptance of the technology likely.
9 State Acceptance State acceptance is anticipated because the UV system uses
well-documented and widely accepted processes for the removal of VOCs
from groundwater and for treatment of the process air emissions. State
regulatory agencies may require permits to operate the treatment system, for
air emissions, and to store contaminated soil cuttings and purge water for
greater than 90 days.
ARAR - Applicable or relevant and appropriate requirements
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However, as the UVB circulation cell is established, the
influent concentrations should be diluted to below levels
requiring more than one pass, thereby limiting the potential
migration of contaminants above target concentrations
from the system.
Process Residuals
The materials handling requirements for the UVB system
include managing spent granular activated carbon, drilling
wastes, purge water, and decontamination wastes
generated during installation, operation, and monitoring of
the treatment system. Spent carbon generated during
treatment of the system air effluent will either be disposed
of or regenerated by the carbon vendor. Tine drilling wastes
are produced during installation of the system well. The
drilling waste can be managed either in 55-gallon drums
or in roll-off type debris bins. Disposal options for this
waste depend on local requirements and on the presence
or absence of contaminants. The options may range from
on-site disposal to disposal in a hazardous waste or
commercial waste landfill.
Purge water is generated during development and sampling
of the groundwater monitoring wells. Purge water can be
managed in 55-gallon drums. Disposal options again
depend on local restrictions and on the presence or
absence of contaminants. Options range from surface
discharge through a National Pollutant Discharge
Elimination System (NPDES) outfall, to disposal through
a Publicly Owned Treatment Works (POTW), to treatment
and disposal at a permitted hazardous waste facility.
Decontamination wastes are generated during installation
and sampling activities. Decontamination wastes
generated during installation include decontamination water
and may include a decontamination pac for the drill rig.
The solid decontamination wastes can be managed in roll-
off type debris boxes, and the liquid wastes can be
managed in 55-gallon drums. Disposal options are similar
to those for drilling wastes and purge water.
Site Requirements
A UVB treatment system consists of several major
components: an 8, 10, 16, or 24-inch dual screen well,
well packer, submersible pump, sieve plate, stripping
reactor, blower, and carbon filter units. A drill rig is required
to install the system well. Once the well has been
completed, the treatment system can be operational within
1 day if all necessary equipment, utilities, and supplies
are available.
The site support requirements needed for the UVB system
are space to set up the carbon adsorption units and
electricity. The system requires standard 120/240 volts
(200 amperes). An electrical pole, a 480-vott transformer,
and electrical hookup between the supply lines, pole, and
the UVB treatment system are necessary to supply power.
The space requirements for the above-ground components
of the UVB system including the UVB system well, off-
gas treatment units, blower, and piping used during the
SITE demonstration are approximately 500 square feet.
Other requirements for installation and routine monitoring
of the system include access roads for equipment
transport, security fencing, and decontamination fluids for
drilling and sampling.
Performance Data
The SITE demonstration for the UVB technology was
designed with three primary and seven secondary
objectives to provide potential users of the technology
with the necessary information to assess the applicability
of the UVB system at other contaminated sites.
Demonstration program objectives were achieved by
collecting groundwater and soil gas samples, as well as
UVB system process air stream samples over a 12-month
period. To meet the objectives, data were collected in
three phases: baseline sampling, long-term sampling, and
dye trace sampling. Baseline and long-term sampling
included the collection of groundwater samples from eight
monitoring wells, a soil gas sample from the soil vapor
monitoring well, and air samples from the three UVB
process air streams both before UVB system startup and
monthly thereafter. In addition, a dye trace study was
conducted to evaluate the system's radius of circulation
cell. This study included the introduction of fluorescent
dye into the groundwater and the subsequent monitoring
of 13 groundwater wells for the presence of dye three times
a week over a 4-month period.
The conclusions of the UVB SITE demonstration at March
AFB are presented below by project objective.
Primary Objectives:
P1 Determine the concentration to which the UVB
technology reduces TCE and DCE in groundwater
discharged from the treatment system.
The UVB effectively removed target compounds from the
groundwater as indicated by the analytical results
presented in Table 2. During the demonstration, TCE
concentrations in samples from the influent well ranged
from 14 jL/g/L to 220 jug/L with an arithmetic mean of
approximately 56 /L/g/L. The UVB system reduced TCE
in the groundwater discharged from the treatment system
to below 5 ug/L in nine out of the 10 monthly monitoring
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events and on average by greater than 94 percent during
the period in which the system operated without apparent
maintenance problems. The mean concentration of TCE
in the water discharged from the system was
approximately 3 ug/L; however, the 95 percent upper
confidence limit for TCE in the treated groundwater was
calculated to be approximately 6/jg/L
The UVB system reduced DCE to less than 1 ji/g/L. in
groundwater discharged from the treatment system;
however, the system's ability to remove DCE cannot be
meaningfully estimated due to the low (less than 4/jg/L)
influent concentration of DCE.
P2 Estimate the radius of circulation cell of the
groundwater treatment system.
The radius of circulation cell of the groundwater treatment
system was estimated by both direct and indirect methods.
The radius of circulation cell was directly measured by
conducting a dye trace study. Based on the dye trace
study, the radius of circulation cell was measured to be at
least 40 feet in the downgradient direction. However, no
dye was observed in wells located 40 feet upgradient or
cross gradient of the UVB system. The radius of circulation
cell was indirectly evaluated by (1) modeling the
groundwater flow, and (2) analyzing aquifer pump test data.
Groundwater flow modeling results conducted by the
developer indicate a radius of circulation cell of 83 feet.
Analysis of aquifer pump test data indicates a radius of
circulation cell of about 60 feet for a traditioned pumping
well near this UVB system. An attempt was made to
indirectly evaluate the radius of circulation eel! using
variations of target compound concentrations and
fluctuations of dissolved oxygen in surrounding
groundwater monitoring wells. However, these methods
did not provide a reliable or conclusive estimate of the
radius of circulation cell due to variables independent of
the UVB system.
P3 Determine whether TCE and DCE concentrations
have been reduced in groundwater (both vertically
and horizontally) within the radius of circulation
cell of the UVB system over the course of the
pilot study.
Based on the demonstration results presented in Table 2,
TCE concentrations in samples from the shallow and
intermediate zone wells were reduced both vertically and
laterally except in the intermediate outer cluster well, which
showed an increase in concentration, TCE concentrations
have been reduced laterally by an average of
approximately 52 percent in samples from the shallow and
intermediate zones of the aquifer No reduction of TCE
was observed in samples from the deep zone, which could
be due to limited duration of monitoring in this zone.
Secondary Objectives:
S1 /Assess homogenization of the groundwater within
the zone of influence.
A convergence and stabilization of TCE concentrations
was observed in samples from the shallow and
intermediate zones of the aquifer, which suggest
homogenization of contaminant concentrations in the
groundwater.
S2 Document selected aquifer geochemical
characteristics that may be affected by oxygenation
and recirculation of treated groundwater.
No clear trends in the field parameters, general chemistry,
or dissolved metals results were observed that would
indicate significant precipitation of dissolved metals,
changes in dissolved organic carbon, or the presence of
dissolved salts caused by the increase in oxygen in
groundwater.
S3 Determine whether the treatment system induces
a vacuum in the vadosezone that suggests vapor
transport.
Although the developer claims that the UVB system has
applications to cleanup of both groundwater and soil gas,
the system installed at Site 31 was designed to remove
halogenated hydrocarbons from the groundwater only. The
VOC concentrations and vacuum measurements in the
vapor monitoring well indicate that transport of
contaminants was not significantly affected by operation
of the UVB system as currently designed. Changes in
system design and operating parameters may lead to
significant transport of contaminants in the vadose zone.
S4 Estimate the capital and operating costs of
constructing a single treatment unit to remediate
groundwater contaminated with TCE and DCE.
Costs are highly site specific. EPA estimates that one-
time capital costs for a single treatment unit are $180,000;
variable annual operation and maintenance costs for the
first year were estimated to be $72,000, and for subsequent
years, $42,000. Based on these estimates, the total cost
for operating a single UVB system for 1 year was calculated
to be $260,000. Since the time required to remediate an
aquifer is site-specific, costs have been estimated for
operation of a UVB system over a range of time for
comparison purposes. Therefore, the cost to operate a
single UVB system was calculated to be $340,000 for 3
years, $440,000 for 5 years, and $710,000 for 10 years.
Additionally, the costs for treatment per 1,000 gallons of
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Table 2: Aquifer Trichloroethene Concentration Summary
Well Description
Baseline 1ST 2NO 3HD
Trichloroethene Concentration (upA)
4™ 5Tn 6™ 7™ 8TH
9™ 10™ 11™ 12™
Wl Intermediate
System Well
22* 57 60 220 35 31 30 22 34
31
14
26 110
W2 Shallow 1'
System Well
16 2.4
38*
Percent Reduction'
NC >98 >98 93 93 87 >97 >95 -12 94 93 95 41
PW1 Shallow Inner 530
Cluster Well
500 440 6?0 608 530 540 600 600 530 30Q 330 340
PW2 Intermediate Inner 750
Cluster Well
1,000 1.900 2,000 1,100 1.200 910 800 620 340 280 240 270
PW3 Deep Inner Cluster 100
Well
130 180 310 230 200 250 NA NA NA NA NA NA
PW4 Shallow Outer 650 760 760 680 818 980 1,100 1,600 1.400 970 300 340 290
Cluster Well
PW5 Intermediate Outer 120 270 310 390 330 350 450 640 360 310 230 210 210
Cluster Well
PW6 Deep Outer Cluster 110 130 110 130 92 140 150 NA NA NA NA NA NA
Well
Concentration affected by water added during drilling and well installation.
1 Percent reduction = [[C (w-l) - C (w.2)] / C (w.t)J x 100; where C (w.t) = deep well concentration and C (w.2) = shallow well concentration
* Concentration affected by system maintenance problems; therefore, results were not used to evaluate primary objectives.
ug/L Micrograms per liter
< Less than
> Greater than
NC Not calculated
NA Not analyzed
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groundwater were estimated to be $260 for 1 year, $110
for 3 years, $88 for 5 years, and $71 for 10 years. The
cost of treatment per 1,000 gallons refers to the amount
of groundwater pumped through the system. Potential
users of the treatment technology should be aware that
typically 60 to 90 percent of the water pumped through
the system is recirculated water. A more detailed document,
the Innovative Technology Evaluation Report (ITER)
contains information on the assumption for these cost
figures.
S5 Document pre- and post-treatment off-gas volatile
organic contaminant levels.
The results from air monitoring of the UVB treatment
system indicated that low concentrations of TCE were
removed from the groundwater. TCE concentrations
reduced by the UVB system correlate to trends observed
in target compound concentrations in the inner cluster
monitoring wells (that is, increasing concentration from
the baseline event to the third monthly monitoring event
with a subsequent decrease in concentrations).
S6 Document system operating parameters.
The temperature of the internal monitoring ports ranged
from 18.5 to 44.7 degrees Celsius; the relative humidity
ranged from 27 to 100 percent; the vacuum pressure
ranged from 13.81 to 15.03 pounds per square inch
absolute; the air flow ranged from 100 to 898 standard
cubic feet per minute; the air velocity ranged from 1,109
to 9,999 feet per minute; and the discharge through the
UVB system was estimated by the developer to be
approximately 22 gallons per minute
S7 Evaluate the presence of aerobic biological
activity in the saturated and vadose zones.
Carbon dioxide concentrations measured in the vapor
monitoring well indicate that carbon dioxide has increased
by more than 2 percent since baseline monitoring. Several
fluctuations in O2 level were observed; however, there
was no evidence of a downward trend of these
concentrations. The minor changes in CO2 and O2
measured suggest that bioactivity in the soil and
groundwater was not significantly enhanced by operation
of the UVB system.
Additionally, CO2 concentrations measured at the UVB
system's intake and after the blower reveal minor
fluctuations of relative CO2 concentration. These results
also suggest that bioactivity due to increased dissolved
oxygen levels in the groundwater was not significantly
enhanced by operation of the UVB system.
Technology Status
Since its introduction in 1986, the UVB technology has
been applied at some 80 sites in Europe. No U.S.
installation of a UVB system has required an NPDES
permit to date. A UVB system was first installed at a
U.S. site in September 1992; currently, there are 22 UVB
systems operating in eight states.
A more detailed document, the ITER, contains more
information on this documentation, the developer has
provided four select case studies that document operation
of the UVB system at sites in the U.S. and Germany. Two
of the cases are from sites in Germany and involve the
remediation of chlorinated hydrocarbons (TCE, 1,1,1-
trichloroethane, and dichloromethane) in the groundwater.
The two cases from the U.S. document the remediation
of groundwater contaminated with benzene, toluene,
ethylbenzene, and xylene at an underground storage tank
site in Troutman, North Carolina, and Weston's
interpretation of the data collected during but independent
of this SITE demonstration.
Sources of Further Information
For further information, contact:
U.S. EPA Project Manager:
Ms. Michelle Simon
U.S. Environmental Protection Agency
26 West Martin Luther King Drive
Cincinnati, OH 45268
513-569-7469
FAX: 513-569-7676
Technology Developer:
I EG Technologies Corporation
Dr. Eric Klingel
1833-D Cross Beam Drive
Charlotte, NC 28217
704-357-6090
FAX: 704-357-6111
March AFB Demonstration Partner:
Roy F. Weston, Inc.
Mr. Jeff Bannon
14724 Ventura Blvd., Suite 1000
Sherman Oaks, CA 91403
(818)971-4900
Fax: (818)971-4901
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