THE ENVIRONMENTAL TECHNOLOGY VERIFICATION
PROGRAM
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Sandia
National
ETV JOINT VERIFICATION STATEMENT
TECHNOLOGY TYPE: GROUNDWATER SAMPLING TECHNOLOGIES
APPLICATION: VOC-CONTAMINATED WATER SAMPLING
TECHNOLOGY NAME: Well Wizard Dedicated Sampling System — Models T1200M
and T1250
COMPANY: QED Environmental Systems Inc.
ADDRESS: 6095 Jackson Road PHONE: (800) 624-2026
Ann Arbor, MI 48106 FAX: (313) 995-1170
WEBSITE: www.micropurge.com
EMAIL: info@qedenv.com
The U.S. Environmental Protection Agency (EPA) has created the Environmental Technology
Verification Program (ETV) to facilitate the deployment of innovative or improved environmental
technologies through performance verification and dissemination of information. The goal of the ETV
Program is to further environmental protection by substantially accelerating the acceptance and use of
improved and cost-effective technologies. ETV seeks to achieve this goal by providing high-quality,
peer-reviewed data on technology performance to those involved in the design, distribution, financing,
permitting, purchase, and use of environmental technologies.
ETV works in partnership with recognized standards and testing organizations and stakeholder groups
consisting of regulators, buyers, and vendor organizations, with the full participation of individual
technology developers. The program evaluates the performance of innovative technologies by
developing test plans that are responsive to the needs of stakeholders, conducting field or laboratory tests
(as appropriate), collecting and analyzing data, and preparing peer-reviewed reports. All evaluations are
conducted in accordance with rigorous quality assurance protocols to ensure that data of known and
adequate quality are generated and that the results are defensible.
The Site Characterization and Monitoring Technologies Pilot, one of 12 technology areas under ETV, is
administered by EPA's National Exposure Research Laboratory. Sandia National Laboratories, a
Department of Energy laboratory, is one of the verification testing organizations within the ETV Site
Characterization and Monitoring Pilot. Sandia collaborated with personnel from the US Geological
Survey (USGS) to conduct a verification study of groundwater sampling technologies. This verification
statement provides a summary of the results from a verification test of the Well Wizard bladder pumps
and pneumatic controller manufactured by QED Environmental Systems Inc.
EPA-VS-SCM-41 The accompanying notice is an integral part of this verification statement. August 2000
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DEMONSTRATION DESCRIPTION
In August 1999, the performance of six groundwater sampling devices was evaluated at the US
Geological Survey Hydrological Instrumentation Facility at the National Aeronautics and Space
Administration (NASA) Stennis Space Center in southwestern Mississippi. Each technology was
independently evaluated in order to assess its performance in the collection of volatile organic
compound- (VOC) contaminated water.
The verification test design incorporated the use of a 5-inch-diameter, 100-foot standpipe at the USGS
facility. The standpipe, serving as an "aboveground" well, was filled with tap water spiked with various
concentration levels of six target volatile organic compounds. The target compounds (1,2-
dichloroethane, 1,1-dichloroethene, trichloroethene, benzene, 1,1,2-trichloroethane, and
tetrachloroethene) were chosen to represent the range of VOC volatility likely to be encountered in
normal sampler use. Water sampling ports along the exterior of the standpipe were used to collect
reference samples at the same time that groundwater sampling technologies collected samples from the
interior of the pipe. A total of seven trials were carried out at the standpipe. The trials included the
collection of low (-20 |Jg/L) and high (-200 |Jg/L) concentrations of the six target VOCs in water at
sampler depths ranging from 17 to 91 feet. A blank sampling trial and an optional "clean-through-dirty"
test were also included in the test matrix. The "clean-through-dirty" test was included to investigate the
potential of contaminant carryover as a sampler is lowered through a "dirty" (high VOC concentration)
layer of water in order to sample an underlying "clean" (low VOC concentration) layer. The test was
optional for samplers such as the Well Wizard dedicated sampling system, which is designed for
permanent deployment in a single monitoring well.
The standpipe trials were supplemented with additional trials at groundwater monitoring wells in the
vicinity of VOC-contaminated groundwater at the NASA Stennis facility. The sampling devices were
deployed in a number of 2-inch and 4-inch wells, along with colocated submersible electric gear pumps
as reference samplers. The principal contaminant at the onsite monitoring wells was trichloroethene.
The onsite monitoring provided an opportunity to observe the operation of the sampling system under
typical field-use conditions.
All technology and reference samples were analyzed by two identical field-portable gas chromatograph-
mass spectrometer (GC/MS) systems that were located at the test site during the verification tests. The
GC/MS analytical method used was a variation of EPA Method 8260 purge-and-trap GC/MS,
incorporating a headspace sampling system in lieu of a purge-and-trap unit. The overall performance of
the groundwater sampling technologies was assessed by evaluating sampler precision and comparability
with reference samples. Other logistical aspects of field deployment and potential applications of the
technology were also considered in the evaluation.
Details of the demonstration, including an evaluation of the sampler's performance, may be found in the
report entitled Environmental Technology Verification Report: QED Environmental Systems Inc. Well
Wizard Dedicated Sampling System, EPA/600/R-00/062.
TECHNOLOGY DESCRIPTION
The Well Wizard is a bladder pump consisting of an internal flexible bladder that is positioned within a
rigid stainless steel pump body. The inner bladder is equipped with one-way inlet and outlet valves and
passively fills with water when the pump is at depth in the well as a result of the hydrostatic pressure
exerted by the surrounding water column. Following the fill cycle, compressed air or nitrogen from a
cylinder or compressor at the wellhead is driven down to the pump through tubing to compress the bladder,
thus driving the water sample up to the surface through a second tubing line. The pumping sequence
consists of repeated fill-compress cycles, using a pneumatic controller positioned at the wellhead. The
controller is used to vary the duration and frequency of the fill-compress cycles in order to deliver the
EPA-VS-SCM-41 The accompanying notice is an integral part of this verification statement. August 2000
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desired sample flow rate at the wellhead. The bladder design offers the advantage of minimizing sample
turbulence, which can result in loss of VOCs in the sample, as well as eliminating contact of the water
sample with the compressed air or nitrogen used to lift the sample to the surface.
QED Environmental offers a complete line of bladder pumps manufactured with various materials. Two
pumps tested during this evaluation were the Model T1220M and the T1250. These two pumps were
essentially the same in design and construction materials with differences only in pump length—the Model
1220 was 1.04 m in length and the 1250 was 0.38 m in length. Both pumps use polytetrafluoroethylene
(Teflon) for the bladder material and 316 stainless steel for the pump body, fittings, and intake screen. The
external diameter of both pumps was 3.8 cm (1.5 inches). The pump intake stainless steel screen mesh size
was 0.25 mm (0.01 inch). Both pumps have a maximum lift capacity of 90 m (300 feet), and flow rates are
adjustable from less than 100 mL/min to over 5 L/min, depending on pump lift.
The QED Model 400 controller is a microprocessor-based controller and was used to control the flow of
compressed nitrogen, obtained from a cylinder at the wellhead, to the bladder pump. The controller has a
weatherproof keypad and a liquid crystal display and is packaged in a durable case that can be hand carried.
The controller has overall dimensions of 18 x 14 x 7.5 inches and a weight of 17 pounds. Drive gas for the
bladder pump can be delivered from compressed gas cylinders or from a field-portable gasoline- or electric-
powered compressor.
Costs for the two bladder pumps tested range from $525 to $650 each and the controller is priced at $2,595.
Teflon-lined polyethylene tubing is also a requirement for most VOC sampling applications and is priced at
$3.30 per foot.
The Model T1220M and T1250 differ only in size. The pumps were used interchangeably in the study and
their performance results are combined. Hereafter, the two pump models are simply referred to as the Well
Wizard sampler.
VERIFICATION OF PERFORMANCE
The following performance characteristics of the Well Wizard dedicated sampling system were
observed:
Precision: The precision of the sampler was determined through the collection of a series of replicate
samples from 4 standpipe trials using low (-20 |Jg/L) and high (-200 |Jg/L) VOC concentrations at 17-
foot and 91-foot collection depths. Each trial included 6 target VOCs for a total of 24 cases. Well
Wizard sampler precision, represented by the relative standard deviation, for all compounds at all
concentrations and sampling depths evaluated in this study, ranged from 3.9 to 19.7%, with a median
value of 7.7%. In 14 cases the relative standard deviation of the Well Wizard samples was greater than
the reference, with Well Wizard precision less than or equal to reference sample precision in the other 10
cases. The F-ratio test was used to assess whether the observed precision differences were statistically
significant. Test results showed that precision differences between Well Wizard and reference samples
were statistically insignificant at the 95% confidence level in 22 of the 24 cases.
Comparability with a Reference: Well Wizard results from the standpipe trials were compared with
results obtained from reference samples collected at the same time. Both Well Wizard and reference
samples were analyzed by the same analytical method using the same GC/MS system. Sampler
comparability is expressed as percent difference relative to the reference data. Sampler differences for
all target VOCs at all concentrations and sampler depths in this study ranged from -17 to 20%, with a
median difference of 1%. The t-test for two sample means was used to assess whether the differences
between Well Wizard and reference sample results were statistically significant. These tests showed that
in 22 of 24 trials, differences were statistically indistinguishable from 0% at the 95% confidence level.
Statistically significant Well Wizard negative bias did not exceed 17%.
EPA-VS-SCM-41 The accompanying notice is an integral part of this verification statement. August 2000
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Versatility: Sampler versatility is the consistency with which the sampler performed over the range of
target compound volatility, concentration level, and sampling depth. Well Wizard performance did not
vary with changes in compound, concentration, or sampler depth. Thus, the Well Wizard is regarded as
a widely versatile sampling device and applicable for sampling the types of VOCs likely to be
encountered under actual field conditions.
Logistical Requirements: The sampler can be deployed and operated in the field by one person. A half-
day of training is generally adequate to become proficient in the use of the system. The system requires
a source of compressed air or nitrogen at the wellhead, such as a compressed gas cylinder or a gas- or
electric-powered compressor. The bladder pumps are designed for dedicated use in a single monitoring
well and are not intended for portable use.
Overall Evaluation: The results of this verification test show that the Well Wizard bladder pump and
associated pneumatic controller can be used to collect VOC-contaminated water samples that are
statistically comparable to reference samples when analyzed with a common analytical method. The
system is designed for use in well-sampling programs that incorporate low-volume purge methodologies.
As with any technology selection, the user must determine if this technology is appropriate for the
application and the project data quality objectives. For more information on this and other verified
technologies, visit the ETV web site at http://www.epa.gov/etv.
Gary J. Foley, Ph.D.
Director
National Exposure Research Laboratory
Office of Research and Development
Samuel G. Varnado
Director
Energy and Critical Infrastructure Center
Sandia National Laboratories
NOTICE: EPA verifications are based on evaluations of technology performance under specific, predetermined
criteria and appropriate quality assurance procedures. The EPA and SNL make no expressed or implied
warranties as to the performance of the technology and do not certify that a technology will always operate as
verified. The end user is solely responsible for complying with any and all applicable federal, state, and local
requirements. Mention of commercial product names does not imply endorsement.
EPA-VS-SCM-41 The accompanying notice is an integral part of this verification statement.
August 2000
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