THE ENVIRONMENTAL TECHNOLOGY VERIFICATION
PROGRAM
oEPA
U.S. Environmental Protection Agency
NSF International
ETV Joint Verification Statement
TECHNOLOGY TYPE: POINT-OF-USE DRINKING WATER TREATMENT
SYSTEM
APPLICATION: REMOVAL OF MICROBIAL CONTAMINATION AGENTS
IN DRINKING WATER
PRODUCT NAME: SEARS KENMORE ULTRAFILTER 500
VENDOR: SEARS ROEBUCK, AND COMPANY
MANUFACTURER: ECOWATER SYSTEMS, INCORPORATED
ADDRESS: 1890 WOODLANE DRIVE PHONE: 1-800-808-9899
WOODBURY,MN 55125 FAX: 651-739-5293
EMAIL: INFO@ECOWATER.COM
NSF International (NSF) manages the Drinking Water Systems (DWS) Center under the U.S.
Environmental Protection Agency's (EPA) Environmental Technology Verification (ETV) Program. The
DWS Center recently evaluated the performance of the Sears Kenmore Ultrafilter 500 point-of-use (POU)
reverse osmosis (RO) drinking water treatment system. NSF performed all of the testing activities and
also authored the verification report and this verification statement. The verification report contains a
comprehensive description of the test.
EPA created the ETV Program 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 accelerating the acceptance and use of improved and
more 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, permitting,
purchase, and use of environmental technologies.
ETV works in partnership with recognized standards and testing organizations, stakeholder groups
(consisting of buyers, vendor organizations, and permitters), and 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.
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ABSTRACT
The Sears Kenmore Ultrafilter 500 RO system was tested for removal of bacteria and viruses at NSF's
Drinking Water Treatment Systems Laboratory. EcoWater Systems submitted ten units for testing, which
were split into two groups of five. One group received 25 days of conditioning prior to challenge testing,
while the second group was tested immediately. Both groups were identically challenged. The challenge
organisms were the bacteriophage viruses fr, MS2, and Phi X 174, and the bacteria Brevundimonas
diminuta and Hydrogenophaga pseudoflava. The test units were challenged at two different inlet
pressures - 40 and 80 pounds per square inch, gauge (psig). The virus challenges were conducted at three
different pH settings (6, 7.5, and 9) to assess whether pH influences the performance of the test units.
The bacteria challenges were conducted only at pH 7.5.
The log 10 reduction data is shown in Tables 2 through 5. The test units removed all challenge organisms
to less-than-detectible levels in all challenges but the pH 9, 80 psig challenge. The data does not show
whether conditioning, inlet pressure or pH influenced bacteria and virus removal.
TECHNOLOGY DESCRIPTION
The following technology description was provided by the manufacturer and has not been verified.
The Ultrafilter 500 is a three-stage POU drinking water treatment system. In addition to the RO
membrane, the system employs carbon filtration. The first stage of treatment is carbon filtration to
remove chlorine as well as suspended particles such as silt, dirt, and rust. The second stage is the RO
membrane, which removes a wide variety of contaminants. The RO treated water is sent to the storage
tank. When the user opens the faucet, the water leaves the storage tank and travels through a second
carbon filter that removes any remaining tastes and odors before it is dispensed. The Ultrafilter 500 is
designed to produce approximately five gallons of wastewater for every gallon of treated water.
The test units were evaluated without the carbon filters in place to eliminate the possibility that these
filters could temporarily trap a portion of the challenge organisms, causing a positive bias of system
performance.
VERIFICATION TESTING DESCRIPTION
Test Site
The testing site was the Drinking Water Treatment Systems Laboratory at NSF in Ann Arbor, Michigan.
A description of the test apparatus can be found in the test/QA plan and verification report. The testing
was conducted in January through March of 2004.
Methods and Procedures
The testing methods and procedures are detailed in the Test/QA Plan for Verification Testing of the Sears
Kenmore Ultrafilter 500 Point-of-Use Drinking Water Treatment System for Removal of Microbial
Contamination Agents. Ten Ultrafilter 500 systems were tested for bacteria and virus removal
performance using the bacteriophage viruses fr, MS2, and Phi X 174, and the bacteria B. diminuta and H.
pseudoflava. The challenge organisms were chosen because they are smaller than most other viruses and
bacteria, and so provide a conservative estimate of performance.
The test units were randomly split into two groups of five. One group was conditioned for 25 days by
operating the units daily using the test water without challenge organisms. The second group was
NSF 04/14/EPADWCTR The accompanying notice is an integral part of this verification statement. September 2004
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challenged without receiving the 25-day conditioning period. The test units were challenged at both 40
and 80 psig inlet pressure. The test water for the bacteria challenges was set to pH 7.5 ± 0.5, while the
virus challenges were conducted at pH 6.0 ± 0.5, 7.5 ± 0.5, and 9.0 ± 0.5. The challenge schedule is
shown in Table 1. The different challenge conditions were intended to evaluate whether inlet pressure or
pH influenced bacteria and virus removal. However, the test water chemistry gave it little buffering
capacity, which made it difficult to keep the pH below 6.5 for the pH 6.0 virus challenges. As a result,
the pH was above 6.5 for three of the four pH 6.0 virus challenges.
Table 1. Challenge Schedule
Day Surrogate Challenge pH Inlet Pressure (psig)
1
2
o
3
4
5
6
7
8
9
10
H. pseudoflava
H. pseudoflava
B. diminuta
B. diminuta
All Viruses
All Viruses
All Viruses
All Viruses
All Viruses
All Viruses
7.5 ±0.5
7.5 ±0.5
7.5 ±0.5
7.5 ±0.5
*6.0±0.5
*6.0±0.5
7.5 ±0.5
7.5 ±0.5
9.0 ±0.5
9.0 ±0.5
40 ±3
80 ±3
40 ±3
80 ±3
40 ±3
80 ±3
40 ±3
80 ±3
40 ±3
80 ±3
*actual pH ranged from 6.7 - 6.9 in three of four days.
On each challenge day, the test units were operated for one tank-fill period (approximately two hours).
The end of this period was evident through engagement of each system's automatic shutoff mechanism,
which causes the flow of reject water to cease. Influent water samples were collected at the beginning
and end of each challenge period. After each test unit ceased operation, the entire contents of the product
water storage tank were emptied into a sterile container, and a subsample was collected for
microbiological analysis. All samples were enumerated in triplicate. Following each challenge period,
the test units were flushed by operating them for one tank-fill period using the test water without
challenge organisms.
VERIFICATION OF PERFORMANCE
Tables 2 and 3 show the bacteria reduction data for the unconditioned units and conditioned units,
respectively. In all challenges for both sets of test units, the bacteria were removed to less than detectible
levels (< 1 CFU/lOOmL). The predominance of non-detectable results does not allow any evaluation of
whether conditioning, inlet pressure or pH influenced the bacteria reduction performance of the RO
membranes.
Tables 4 and 5 show the virus reduction data for the unconditioned units and conditioned units,
respectively. In all challenges but the pH 9, 80 psig challenge, both sets of test units removed all three
viruses to less than detectible levels (< 1 PFU/mL). The maximum mean effluent count for the pH 9, 80
psig challenges was 11 PFU/mL, which corresponds to the 3.0 logio reduction of fr for unconditioned unit
3. As with the bacteria, the predominance of non-detectable results does not allow an evaluation of the
effect of conditioning, inlet pressure, or pH on RO membrane performance. Complete descriptions of the
verification testing results are included in the verification report.
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pH
7.5
7.5
PH
7.5
7.5
Table 2. Bacteria Log Reduction Data for Unconditioned Units
Logic T _ , ,.
Pressure Challenge Influent Logio Reduction
(psig) Organisms Challenge Unit 1 Unit 2 Unit 3 Unit 4 Unit 5
40 H. pseudoflava 6.6
B. diminuta 6.4
80 H. pseudoflava 6.0
B. diminuta 6.6
All effluents non-detect
Log reductions equal to influents
All effluents non-detect
Log reductions equal to influents
Table 3. Bacteria Log Reduction Data for Conditioned Units
Logic T _ , ,.
Pressure Challenge Influent Logic Reduction
(psig) Organisms Challenge Unit 1 Unit 2 Unit 3 Unit 4 Unit 5
40 H. pseudoflava 6.6
B. diminuta 7.1
80 H. pseudoflava 6.0
B. diminuta 6.8
Table 4. Virus Logio Reduction Data
Challenge Conditions
Target Measured Pressure Challenge Logio Influent
pH pH (psig) Organisms Challenge
6.0 + 0.5
6.0 + 0.5
7.5+0.5
7.5+0.5
9.0 + 0.5
9.0 + 0.5
fr 5.0
6.86 40 MS2 4.8
Phi X 174 4.5
fr 5.4
6.88 80 MS2 5.2
Phi X 174 4.0
fr 4.3
7.69 40 MS2 5.0
Phi X 174 5.3
fr 4.0
7.91 80 MS2 4.9
Phi X 174 4.4
fr 5.3
8.71 40 MS2 5.1
Phi X 174 4.4
fr 4.1
8.67 80 MS2 3.9
Phi X 174 3.7
All effluents non-detect
Log reductions equal to influents
All effluents non-detect
Log reductions equal to influents
for Unconditioned Units
Logic Reduction
Unit 1 Unit 2 Unit 3 Unit 4 Unit 5
All effluents non-detect
Log reductions equal to influents
All effluents non-detect
Log reductions equal to influents
All effluents non-detect
Log reductions equal to influents
All effluents non-detect
Log reductions equal to influents
All effluents non-detect
Log reductions equal to influents
3.8 3.6 3.0 4.1 4.1
3.9 3.6 2.9 3.9 3.9
3.7 3.7 3.7 3.7 3.7
NSF 04/14/EPADWCTR
The accompanying notice is an integral part of this verification statement. September 2004
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Table 5. Virus Logio Reduction Data for Conditioned Units
Challenge Conditions Log10 Reduction
Target Measured Pressure Challenge Log10 Influent
pH pH (psig) Organisms Challenge Unit 1 Unit 2 Unit 3 Unit 4 Unit 5
6.0 + 0.5 6.48
6.0 + 0.5 6.69
7.5+0.5 7.45
7.5+0.5 7.56
9.0 + 0.5 8.73
9.0 + 0.5 8.73
fr
40 MS2
Phi X 174
fr
80 MS2
Phi X 174
fr
40 MS2
Phi X 174
fr
80 MS2
Phi X 174
fr
40 MS2
Phi X 174
fr
80 MS2
Phi X 174
4.8
4.5
3.8
4 5
4.4
4.2
5 3
5.0
4.3
4 9
4.7
3.9
5 6
5.4
3.8
5.1
4.8
4.5
Log
Log
Log
Log
Log
5.1
4.5
4.5
All effluents non-detect
; reductions equal to influents
All effluents non-detect
; reductions equal to influents
All effluents non-detect
; reductions equal to influents
All effluents non-detect
; reductions equal to influents
All effluents non-detect
; reductions equal to influents
4.6 5.1 5.1 5.1
4.3 4.8 4.8 4.5
4.5 4.5 4.5 4.5
Quality Assurance/Quality Control (QA/QC)
NSF provided technical and quality assurance oversight of the verification testing as described in the
verification report, including an audit of nearly 100% of the data. NSF personnel also conducted a
technical systems audit during testing to ensure the testing was in compliance with the test plan. A
complete description of the QA/QC procedures is provided in the verification report.
Orginal signed by
E. Timothy Oppelt
09/20/04
Orginal signed by
Gordon Bellen
09/23/04
E. Timothy Oppelt Date
Director
National Homeland Security Research Center
United States Environmental Protection
Agency
Gordon Bellen
Vice President
Research
NSF International
Date
NOTICE: Verifications are based on an evaluation of technology performance under specific,
predetermined criteria and the appropriate quality assurance procedures. EPA and NSF 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 corporate names, trade
names, or commercial products does not constitute endorsement or recommendation for use of
specific products. This report is not an NSF Certification of the specific product mentioned
herein.
NSF 04/14/EPADWCTR
The accompanying notice is an integral part of this verification statement. September 2004
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Availability of Supporting Documents
Copies of the test protocol, the verification statement, and the verification report (NSF
report # NSF 04/14/EPADWCTR) are available from the following sources:
(NOTE: Appendices are not included in the verification report. Appendices are available
from NSF upon request.)
1. ETV Drinking Water Systems Center Manager (order hard copy)
NSF International
P.O. Box 130140
Ann Arbor, Michigan 48113-0140
2. NSF web site: http://www.nsf.org/etv (electronic copy)
3. EPA web site: http://www.epa.gov/etv (electronic copy
NSF 04/14/EPADWCTR The accompanying notice is an integral part of this verification statement. September 2004
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