THE ENVIRONMENTAL TECHNOLOGY VERIFICATION
PROGRAM
&EPA
U.S. Environmental Protection Agency
NSF International
ETV Joint Verification Statement
TECHNOLOGY TYPE: POINT-OF-USE DRINKING WATER TREATMENT
SYSTEM
APPLICATION: REMOVAL OF MICROBIAL CONTAMINANTS IN
DRINKING WATER
PRODUCT NAME: WATTS PREMIER WP-4V
VENDOR: WATTS PREMIER
ADDRESS: 1725 WEST WILLIAMS DR.
SUITE C-20
PHOENIX, AZ 85027
PHONE: 800-752-5582
INTERNET http://www.wattspremier.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 Watts Premier WP-4V 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 Watts Premier WP-4V four-stage POU RO system was tested for removal of bacteria and viruses at
NSF's Drinking Water Treatment Systems Laboratory. Five systems were challenged with the
bacteriophage viruses fir and MS2, and the bacteria Brevundimonas diminuta. The virus challenges were
conducted at three different pH settings (6, 7.5, and 9) to assess whether pH influences the performance of
the RO membrane. The bacteria challenges were conducted only at pH 7.5.
The challenge concentrations ranged from 3.8 to 5.0 logs for the viruses, and 6.4 to 7.2 logs for the
bacteria. The log reductions ranged from 1.3 to 6.4 logic for B. diminuta, with an average of 2.1 Iogi0.
The virus log reductions ranged from 1.4 to 3.6 logio for fir, and 1.2 to 3.7 logio for MS2. The average
virus logio reductions were 2.5 and 2.7, respectively. The virus challenge data does not indicate that the
pH of the challenge water influenced removal by the RO membrane. See Table VS-2 below for the
complete log reduction data.
TECHNOLOGY DESCRIPTION
The following technology description was provided by the manufacturer and has not been verified.
The WP-4V is a four-stage POU drinking water treatment system using sediment filtration, activated
carbon filtration, and reverse osmosis. Treated water is stored in a three-gallon storage tank. The WP-4V
is certified by NSF to NSF/ANSI Standard 58 - Reverse Osmosis Drinking Water Treatment Systems. It
has a certified production rate of 9.06 gallons per day.
Incoming water first passes through a sediment filter to remove particulate matter, such as rust and silt,
and then through a carbon filter to remove chlorine or other contaminants. The third stage of treatment is
the reverse osmosis membrane, which removes a wide variety of inorganic and larger molecular weight
organic contaminants, and also protozoan cysts such as Cryptosporidium and Giardia. The permeate
water is sent to a 3-gallon maximum capacity storage tank. Upon leaving the storage tank, the water
passes through a second carbon filter to remove organic chemicals and other taste and odor causing
substances before dispensing through the faucet. The pre-membrane carbon and sediment filters were not
tested, because they are only designed to remove chlorine and particulate matter to protect the RO
membrane.
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 June and July of 2005.
Methods and Procedures
The testing methods and procedures are detailed in the Test/QA Plan for Verification Testing of the Watts
Premier WP-4V Point-of-Use Drinking Water Treatment System for Removal of Microbial
Contamination Agents. Five WP-4V systems were tested for bacteria and virus removal performance
using the bacteriophage viruses fir and MS2, and the bacteria Brevundimonas diminuta. The challenge
organisms were chosen because they are smaller than most other viruses and bacteria, and so provide a
conservative estimate of performance. NSF also used a genetically engineered strain of B. diminuta. The
NSF Microbiology Laboratory inserted into a culture of B. diminuta strain 19146 a gene conferring
resistance to the antibiotic kanamycin. This allowed the Microbiology Laboratory to use a growth media
NSF 06/12b/EPADWCTR The accompanying notice is an integral part of this verification statement. July 2006
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amended with 50 jog/mL of kanamycin to prohibit heterotrophic plate count (HPC) bacteria in the treated
water samples from growing along with the kanamycin resistant B. diminuta.
Five systems were evaluated. The systems were installed on a test rig and conditioned according to the
vendor's instructions (fill the storage tanks and dispensing the contents to a drain three times), and then
were conditioned for another five days. Prior to testing, the systems were evaluated for reduction of total
dissolved solids (TDS) to ensure that the systems undergoing testing were representative of the expected
performance of the system.
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 VS-1. The
virus challenges were conducted at different pH settings to evaluate whether the surface charges of the
viruses influenced their removal through electrostatic forces versus mechanical filtration. Viruses have
different surface charges, or different strengths of negative or positive charge, depending on their
isoelectric point and the pH of the water. The isoelectric point is the pH at which the virus surface is
neutrally charged. MS2's isoelectric point is pH 3.9, and fr's is pH 8.9. In solutions above the isoelectric
point, the virus is negatively charged. Below the isoelectric point, the virus is positively charged.
Table VS-1. Challenge Schedule
Day Surrogate Challenge pH
1 B. diminuta 7.5 ± 0.5
2 fr and MS2 6.0 ± 0.5
3 fr and MS2 7.5 ± 0.5
4 Kanamycin Resistant B. diminuta 7.5 ± 0.5
5 fr and MS2 9.0 ± 0.5
For each challenge, the systems were operated for one tank-fill period (approximately four to five 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 system ceased operation, the contents of the product water
storage tanks were emptied into sterile containers, and samples were collected for microbiological
analysis. All samples were enumerated in triplicate. Following each challenge period, the systems were
flushed by operating them for one tank-fill period using water without challenge organisms.
VERIFICATION OF PERFORMANCE
As discussed above, the systems were first subjected to a TDS reduction test to verify that the RO
membranes would perform as expected. The observed TDS reduction ranged from 89% to 96%. The
certified TDS reduction for the WP-4V is 97%.
The bacteria and virus logio reduction data is presented in Table VS-2. The logio reduction of B. diminuta
("normal" and kanamycin resistant B. diminuta combined) ranged from 1.3 to 6.4, with an average logio
reduction of 1.9. The challenge organisms were detected in the effluent samples for all test units but Unit
2 for the "normal" B. diminuta challenge. Since the Unit 2 effluent count for kanamycin resistant B.
diminuta was 4.3 logio, and all other effluent samples had bacteria counts greater than 4 logio (data not
shown), it is possible that there was a sampling or analytical error associated with the Unit 2 "normal" B.
diminuta sample. Therefore, that sample was not included in the mean logio reduction calculation for the
bacteria.
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The virus challenge data showed similar performance. The logio reduction of the fir virus ranged from 1.4
to 3.6, with an overall mean of 2.5. The logic reduction of MS2 ranged from 1.2 to 3.7, with an overall
mean of 2.6. A visual comparison of the logio reductions versus the challenge water pH shows the mean
logio reductions decreasing with increasing pH. However, an examination of the 95% confidence
intervals around the means (see verification report for data) shows that the decreases are not statistically
significant.
The minimum observed log reductions equal removal of 95% of B. diminuta, and 94% of the viruses.
Table VS-2. Bacteria and Virus Log Reduction Data
Initial Final Log10 „ . . ,, T _ , ..
Measured Measured Challenge Influent Geometric Mean Loglo Reduction
Target pH pH pH Organisms Challenge Unit 1 Unit 2 Unit 3 Unit 4 Unit 5
7.5+0.5 7.6 7.8 B. diminuta 6.4 1.8
Kanamycin
7.5 + 0.5 7.5 7.8 Resistant 7.2 1.4
B. diminuta
6.0 ±0.5 6.1 6.5 fr 3.9 1.8
MS2 3.8 2.3
7.5 ±0.5 7.5 7.7 fr 4.5 1.9
MS2 4.2 1.7
9.0 ±0.5 8.9 9.0 fr 5.0 1.4
MS2 4.6 1.2
*Number not included in mean log reduction calculation.
6.4* 1.3 1.5 1.6
2.9 2.6 2.6 3.1
3.1 3.6 3.4 3.0
3.4 3.7 3.6 2.9
2.4 2.3 3.1 2.8
2.4 2.4 3.4 3.2
2.3 2.1 2.3 2.6
2.4 2.0 2.3 3.0
Overall Means: B. diminuta
fr
MS2
QUALITY ASSURANCE/QUALITY CONTROL (QA/QC)
NSF provided technical and quality assurance oversight of the verification testing as described in
verification report, including a review of nearly 100% of the data. NSF personnel also conducted
technical systems audit during testing to ensure the testing was in compliance with the test plan.
complete description of the QA/QC procedures is provided in the verification report.
Mean
1.5
2.4
2.9
3.1
2.5
2.5
2.1
2.1
1.9
2.5
2.6
the
a
A
NSF 06/12b/EPADWCTR
The accompanying notice is an integral part of this verification statement.
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July 2006
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Original signed by Sally Gutierrez 08/11/06 Original signed by Robert Ferguson 08/23/06
Sally Gutierrez Date Robert Ferguson Date
Director Vice President
National Risk Management Research Laboratory Water Systems
Office of Research and Development NSF International
United States Environmental Protection Agency
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.
Availability of Supporting Documents
Copies of the test protocol, the verification statement, and the verification report (NSF
report # NSF 06/12b/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. Electronic PDF copy
NSF web site: http://www.nsf.org/etv
EPA web site: http://www.epa.gov/etv
NSF 06/12b/EPADWCTR The accompanying notice is an integral part of this verification statement. July 2006
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