June 2004
NSF04/12/EPADWCTR
Environmental Technology
Verification Report
Physical Removal of Microbial
Contamination Agents in Drinking Water
Watts Premier
Ultra 5 Reverse Osmosis Drinking Water
Treatment System
Prepared by
NSF International
Under a Cooperative Agreement with
U.S. Environmental Protection Agency
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THE ENVIRONMENTAL TECHNOLOGY VERIFICATION
PROGRAM
oEPA
U.S. Environmental Protection Agency
* J NSF International
ETV Joint Verification Statement
TECHNOLOGY TYPE: POINT-OF-USE REVERSE OSMOSIS DRINKING WATER
TREATMENT SYSTEM
APPLICATION: REMOVAL OF MICROBIAL CONTAMINATION AGENTS IN
DRINKING WATER
PRODUCT NAME: WATTS PREMIER ULTRA 5
COMPANY: WATTS PREMIER, INC.
ADDRESS: 1725 WEST WILLIAMS STREET PHONE: 800-752-5582
PHOENIX, AZ 85027 FAX: 623-931-0191
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, Inc. Ultra 5 point-of-use (POU)
reverse osmosis 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.
NSF 04/12/EPADWCTR The accompanying notice is an integral part of this verification statement. June 2004
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ABSTRACT
The Watts Premier Ultra 5 was tested for removal of bacteria and viruses at NSF's Drinking Water
Treatment Systems Laboratory. Watts Premier submitted ten units, 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. Due to an incorrectly installed shut-off valve on one of the unconditioned units, only
four in this group were tested. Both groups were challenged identically. The challenge organisms were
the 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) with the intent to assess whether pH influenced the performance of the test units. The bacteria
challenges were only conducted at pH 7.5.
In most cases, the test units significantly reduced the challenge organisms, with reductions greater than
4.0 logic. The logio reduction data is shown in Tables 3 through 6. Overall, the performance of the
conditioned units was better than that of the unconditioned units. Also, the unconditioned units exhibited
wider unit-to-unit performance variation than the conditioned units. The logio reduction data does not
conclusively show that inlet pressure or pH influenced test unit performance.
TECHNOLOGY DESCRIPTION
The following technology description was provided by the manufacturer and has not been verified.
The Watts Premier Ultra 5 is a five-stage POU drinking water treatment system. It employs carbon
filtration and reverse osmosis processes to remove contaminants from drinking water. It is sold with a
faucet that is installed at the kitchen sink, and the system itself is installed either under the kitchen sink or
in another location.
During operation, inlet water first passes through a sediment filter, and then through two carbon block
filters. The fourth stage is passage through the reverse osmosis membrane. The portion of the inlet water
that passes through the membrane travels to the product water storage tank. When the user opens the
faucet, the water leaves the storage tank and travels through a final carbon filter before exiting the faucet.
The system is designed to produce approximately 12 gallons of reject water for each gallon of treated
water produced.
The test units were evaluated without the carbon filters or sediment filter 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 during testing.
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/quality assurance (QA) plan and verification
report. The testing was conducted in September and October of 2003.
Methods and Procedures
The testing methods and procedures are detailed in the Test/QA Plan for Verification Testing of the Watts
Premier Ultra 5 Point-of-Use Reverse Osmosis Drinking Water Treatment System for Removal of
Microbial Contamination Agents. Nine test units were verified for bacteria and virus removal
NSF 04/12/EPADWCTR The accompanying notice is an integral part of this verification statement. June 2004
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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.
Watts Premier submitted ten units, which were split into two groups of five according to the performance
of each membrane in the manufacturer's quality control testing. One group was conditioned for 25 days
prior to challenge testing by operating the units daily using the test water without challenge organisms.
The second group was challenged without receiving the 25-day conditioning period. Due to an
incorrectly installed shut-off valve on one of the unconditioned units, only four in this group were tested.
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. The test water for the virus challenges was set at pH 6.0 ± 0.5, 7.5 ±
0.5, and 9.0 ± 0.5. However, it had a low buffering capacity, so the lab technicians had difficulty
maintaining the pH within the 9.0 ± 0.5 range. As a result, the pH for the conditioned units pH 9, 80 psig
challenge was only 7.9. The test water pH values for all other challenges were within the allowable
ranges. These challenge conditions were intended to evaluate whether inlet pressure or pH influences
bacteria and virus removal. Table 1 shows the challenge schedule for the conditioned units, while Table 2
shows the schedule for the unconditioned units. The challenge levels ranged from 3.4 to 6.4 logic for the
viruses, and 6.7 to 8.4 logio for the bacteria.
Table 1. Conditioned Units Challenge Schedule
pH Inlet Pressure
Day Challenge Organism(s) (±0.5 units) (± 3 psig)
1
2
3
4
5
6
7
8
9
10
Day
1
2
3
4
5
6
7
8
9
10
All Viruses
All Viruses
All Viruses
All Viruses
All Viruses
All Viruses
H. pseudoflava
H. pseudoflava
B. diminuta
B. diminuta
Table 2. Unconditioned
Challenge Organism(s)
H. pseudoflava
H. pseudoflava
B. diminuta
B. diminuta
All Viruses
All Viruses
All Viruses
All Viruses
All Viruses
All Viruses
6.0
6.0
7.5
7.5
9.0
9.0
7.5
7.5
7.5
7.5
Units Challenge
pH
(±0.5 units)
7.5
7.5
7.5
7.5
6.0
6.0
7.5
7.5
9.0
9.0
40
80
40
80
40
80
80
40
40
80
Schedule
Inlet Pressure
(± 3 psis)
80
40
40
80
40
80
40
80
40
80
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On each challenge day, the test units were operated for one tank-fill period (approximately six to eight
hours). The end of this period was evident through engagement of the system's automatic shutoff
mechanism, which causes the flow of reject water to cease. At 40 psig, not all of the shut-off mechanisms
engaged after 8 hours of operation due to the low pressure. The storage tanks were nearly full in these
instances, so operation of the units was stopped manually.
Influent water samples were collected at the beginning and end of the 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
The bacteria reduction data are presented in Tables 3 and 4, and the virus reduction data in Tables 5 and
6. An examination of the bacteria reduction data shows that for the five conditioned test units, in only
one case (unit 4 for B. diminuta at pH 7.5, 40 psig) was one of the bacteria species detected in the effluent
samples. In contrast, for the unconditioned units, there were 13 cases out of 16 where the challenge
bacteria were detected in the effluents.
An evaluation of the virus reduction data shows that overall, the conditioned units performed better than
the unconditioned units. The mean logio reductions and mean logio effluent counts are shown in the
bottom right corner of Tables 5 and 6. A comparison of the mean logio effluent counts for the
unconditioned versus conditioned units shows that the conditioned units performed approximately 0.3 to
1.7 logio better than the unconditioned units.
The unit-to-unit performance variation for the unconditioned units was wider than for the conditioned
units, and the performance of each unconditioned unit also varied more from day-to-day. Also, the
unconditioned units had many cases where bacteria reduction performance was less than virus reduction
performance. The reasons for these observations are not known, but the data suggest that conditioning the
systems improves and/or stabilizes their performance. The data does not conclusively show whether inlet
pressure or pH influenced test unit performance.
Table 3. Bacteria Log Reduction Data for Unconditioned Units
Pressure Challenge Log10 Influent Geometric Mean Log10 Reduction
pH (psig) Organisms Challenge Unit 1 Unit 2 Unit 3 Unit 4
7.5
40
H. pseudoflava
B. diminuta
6.9
8.2
4.4
8.2
4.9
3.0
2.2
2.0
1.6
8.2
7.5
80
H. pseudoflava
B. diminuta
6.9
8.1
4.6
3.5
6.6
2.2
1.9
3.3
3.0
8.1
Table 4. Bacteria Log Reduction Data for Conditioned Units
Pressure Challenge Log10 Influent Geometric Mean Log10 Reduction
pH (psig) Organisms Challenge Unit 1 Unit 2 Unit 3 Unit 4 Unit 5
~1~5 40 H. pseudoflava 6J 6J 6J 6J 6J 6.7
B. diminuta 8.3 8.3 8.3 8.3 7.2 8.3
7.5
80
H. pseudoflava
B. diminuta
6.7
8.4
6.7
8.4
6.7
8.4
6.7
8.4
6.7
8.4
6.7
8.4
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Table 5. Virus Log Reduction
Challenge Conditions Logic
Target Actual Pressure Challenge Influent
Data for Unconditioned Units
Geometric Mean Logic Reduction
pH pH (psig) Organisms Challenge Unit 1 Unit 2 Unit 3
6.0 ±0.5 6.5 40 fr
MS2
Phi X 174
6.0 ±0.5 6.2 80 fr
MS2
Phi X 174
7.5 ±0.5 7.6 40 fr
MS2
Phi X 174
7.5 ±0.5 7.7 80 fr
MS2
Phi X 174
9.0 ±0.5 8.7 40 fr
MS2
Phi X 174
9.0 ±0.5 9.0 80 fr
MS2
Phi X 174
6.3
6.1
5.0
5.9
5.8
4.9
5.9
5.6
5.7
5.8
5.7
5.9
5.8
5.6
5.7
6.0
5.7
5.6
fr mean3
MS2 mean3
PhiX
174 mean3
4.8
5.62
5.0
4.5
4.5
4.62
4.0
3.8
3.7
4.6
4.4
4.3
4.4
4.1
3.8
4.6
4.7
4.1
4.5
4.5
4.3
3.1
3.0
2.4
3.2
3.0
2.8
2.9
2.7
2.3
2.5
2.6
2.6
2.9
2.7
2.6
3.5
3.4
3.5
3.0
2.9
2.7
2.9
2.8
2.3
3.3
3.3
2.4
4.9
5.0
5.72
4.3
4.3
3.7
4.2
4.1
3.3
3.7
3.8
3.5
3.9
3.9
3.5
Unit 4
4.6
4.7
5.02
5.9
5.8
4.9
4.4
4.3
4.3
5.5
5.42
5.1
4.8
4.8
4.1
5.1
5.1
4.5
5.1
5.0
4.7
Mean1
3.8
4.0
3.7
4.2
4.2
3.7
4.1
4.0
4.0
4.2
4.2
3.9
4.1
3.9
3.5
4.2
4.3
3.9
4.1
4.1
3.6
Log10
Mean
Effluent
Count
2.5
2.1
1.3
1.7
1.6
1.2
1.8
1.6
1.7
1.6
1.5
2.0
1.7
1.7
2.2
1.8
1.4
1.7
1.9
1.7
1.7
1 The arithmetic mean of all test units for each challenge.
2 Triplicate count had two
"non-detect"
3 The arithmetic mean for all challenges
agar plates.
against
each test unit.
NSF 04/12/EPADWCTR
The accompanying notice is an integral part of this verification statement.
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June 2004
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Table 6. Virus Log Reduction Data for Conditioned Units
Challenge Conditions Log10 Geometric Mean Logic Reduction
Target Actual Pressure Challenge Influent
pH pH (psig) Organisms Challenge Unit 1 Unit 2 Unit 3 Unit 4 Unit 5
6.0 ±0.5 6.5 40 fr 5.1 3.6 4.1 4.0
MS2 4.8 3.2 3.7 3.8
Phi X 174 3.4 3.4 3.4 3.4
6.0 ±0.5 6.4 80 fr 6.1 4.6 4.2 4.3
MS2 6.0 4.6 4.2 4.2
Phi X 174 3.8 3.8 3.8 3.8
7.5 ±0.5 7.5 40 fr 6.4 4.2 4.8 4.7
MS2 6.2 4.2 4.5 4.8
Phi X 174 4.0 3.7 4.02 4.02
7.5 ±0.5 7.3 80 fr 6.3 4.8 5.6 5.6
MS2 6.1 5.2 5.5 5.6
PhiX174 4.1 4.1 4.12 4.1
9.0 ±0.5 8.9 40 fr 6.2 4.4 4.2 4.3
MS2 5.8 4.2 4.0 4.2
PhiX174 4.1 4.1 4.1 4.1
9.0 ±0.5 7.93 80 fr 6.0 4.4 4.9 4.7
MS2 5.9 4.3 5.9 4.8
Phi X 174 4.0 4.0 4.0 4.0
frmean4 4.3 4.6 4.6
MS2mean4 4.3 4.6 4.6
Phi X 174 mean4 3.9 3.9 3.9
1 The arithmetic mean of all test units for each challenge.
2 Triplicate count had two "non-detect" agar plates.
4.8
4.1
3.4
4.7
4.8
3.8
4.8
4.7
4.0
5.3
4.9
4.1
4.3
4.1
4.1
4.7
4.9
4.0
4.8
4.6
3.9
4.0
3.2
3.4
4.6
3.7
3.8
4.2
4.3
3.7
4.8
5.0
4.12
4.3
4.2
4.1
4.6
4.6
4.0
4.4
4.2
3.9
Mean1
4.1
3.6
3.4
4.5
4.3
3.8
4.5
4.5
3.9
5.2
5.2
4.1
4.3
4.1
4.1
4.7
4.9
4.0
4.6
4.4
3.9
Mean
Effluent
Count
1.0
1.2
0.0
1.6
1.7
0.0
1.9
1.7
0.1
1.1
0.9
0.1
1.9
1.7
0.0
1.3
1.0
0.0
1.5
1.4
0.0
3 See section 5.8.3 of verification report for discussion of pH variance.
4 The arithmetic mean for all challenges against each test unit.
QUALITY ASSURANCE/QUALITY CONTROL (QA/QC)
NSF personnel conducted a technical systems audit during testing to
compliance with the test plan. NSF also conducted a data quality audit
the
verification report referenced below for more QA/QC information.
ensure
that
the testing was in
of 100% of the data.
Please see
NSF 04/12/EPADWCTR
The accompanying notice is an integral part of this verification statement.
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Original signed by Original signed by
E. Timothy Oppelt 07/12/04 Gordon Bellen 07/16/04
E. Timothy Oppelt Date Gordon Bellen Date
Director Vice President
National Homeland Security Research Center Research
United States Environmental Protection Agency NSF International
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 a 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
04/12/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/dws/dws reports.html and from
http://www.nsf.org/etv/dws/dwsjroject documents.html (electronic copy)
3. EPA web site: http://www.epa.gov/etv (electronic copy)
NSF 04/12/EPADWCTR The accompanying notice is an integral part of this verification statement. June 2004
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June 2004
Environmental Technology Verification Report
Physical Removal of Microbial Contamination Agents in Drinking
Water
Watts Premier
Ultra 5 Reverse Osmosis Drinking Water Treatment System
Prepared by:
NSF International
Ann Arbor, MI 48105
Under a cooperative agreement with the U.S. Environmental Protection Agency
Jeffrey Q. Adams, Project Officer
National Risk Management Research Laboratory
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
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Notice
The U.S. Environmental Protection Agency (EPA) through its Office of Research and
Development has financially supported and collaborated with NSF International (NSF) under
Cooperative Agreement No. R-82833301. This verification effort was supported by the Drinking
Water Systems (DWS) Center, operating under the Environmental Technology Verification
(ETV) Program. This document has been peer reviewed, reviewed by NSF and EPA, and
recommended for public release.
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Foreword
The U.S. Environmental Protection Agency (EPA) is charged by Congress with protecting the
Nation's land, air, and water resources. Under a mandate of national environmental laws, the
Agency strives to formulate and implement actions leading to a compatible balance between
human activities and the ability of natural systems to support and nurture life. To meet this
mandate, EPA's research program is providing data and technical support for solving
environmental problems today and building a science knowledge base necessary to manage our
ecological resources wisely, understand how pollutants affect our health, and prevent or reduce
environmental risks in the future.
The Environmental Technology Verification (ETV) Program has been established by EPA to
verify the performance characteristics of innovative technologies, and to report this objective
information to permitters, buyers, and users of the technologies. Verification organizations
oversee and report verification activities based on testing and quality assurance protocols
developed with input from major stakeholders and customer groups associated with the
technology area. ETV consists of seven environmental technology centers. Information about
each of these centers can be found on the internet at http://www.epa.gov/etv/.
Under a cooperative agreement, NSF International is partnering with EPA to plan, coordinate,
and conduct verification tests for point-of-use, point-of-entry, and small community water
treatment systems. Further information can be found on the internet at
http://www.epa.gov/etv/centers/center2.html, or http://www.nsf.org/etv.
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Table of Contents
Section Page
Verification Statement VS-i
Title Page i
Notice ii
Foreword iii
Table of Contents iv
List of Tables vi
List of Figures vi
Abbreviations and Acronyms vii
Acknowledgements viii
Chapter 1 Introduction 1
1.1 Environmental Technology Verification (ETV) Purpose and Program Operation 1
1.2 Development of Test/Quality Assurance (QA) Plan 1
1.2.1 Bacteria and Virus Surrogates 2
1.2.2 Inlet Pressure 3
1.2.3 Long-Term Conditioning 3
1.3 Testing Participants and Responsibilities 3
1.3.1 NSF 4
1.3.2 Watts Premier 4
1.3.3 U.S. Environmental Protection Agency 4
Chapter 2 Equipment Description 5
2.1 RO Membrane Operation 5
2.2 Equipment Capabilities 5
2.3 Trade Names 5
2.4 System Components 5
2.5 System Operation 6
2.6 Rate of Waste Production 6
2.7 Equipment Operation Limitations 6
2.8 Operation and Maintenance Requirements 6
Chapter 3 Methods and Procedures 9
3.1 Test Equipment 9
3.1.1 Equipment Selection 9
3.1.2 Test Unit Configuration 9
3.2 Verification Test Procedure 9
3.2.1 Test Rig 9
3.2.2 Test Rig Sanitization 9
3.2.3 Test Water 10
3.2.3.1 Base Water 10
3.2.3.2 Bacteria and Virus Challenges 11
3.2.4 Test Unit Operation 12
3.2.4.1 Test Unit Installation 12
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3.2.4.2 IDS Reduction System Check 12
3.2.4.3 Long-Term Conditioning 12
3.2.4.4 Conditioned Units Challenge Testing 13
3.2.4.5 Unconditioned Units Testing 14
3.3 Analytical Methods 15
3.3.1 Water Quality Analytical Methods 15
3.3.2 Microbiology Methods 15
3.3.2.1 Sample Processing, and Enumeration of Viruses 15
3.3.2.2 Bacteria Cultivation 16
3.3.2.3 Preparation of Bacteria Challenge Suspensions 16
3.3.2.4 Bacteria Sample Processing and Enumeration 16
Chapter 4 Results and Discussion 17
4.1 TDS Reduction 17
4.2 Virus Reduction 17
4.2.1 Unconditioned Scenario versus Conditioning Scenario 20
4.2.2 Inlet Pressure Influence 20
4.2.3 Performance Comparison at Different pH Settings 20
4.3 Bacteria Reduction 20
4.4 Unit-To-Unit Variability 21
Chapters QA/QC 23
5.1 QA/QC Responsibilities 23
5.2 Test Procedure QA/QC 23
5.3 Water Chemistry Analytical Methods QA/QC 23
5.4 Microbiology Laboratory QA/QC 23
5.4.1 Growth Media 23
5.4.2 Bacteria Cell Size 24
5.4.3 Sample Processing and Enumeration 24
5.4.4 Heterotrophic Bacteria Interference 24
5.5 Sample Handling 25
5.6 Documentation 25
5.7 Data Quality Indicators 25
5.7.1 Representativeness 25
5.7.2 Accuracy 25
5.7.3 Precision 25
5.7.4 Statistical Uncertainty 26
5.7.5 Completeness 26
5.7.5.1 Completeness Measurements 27
5.7.5.1.1. Number of Units Tested 27
5.7.5.1.2. pH, Temperature, and Total Chlorine 27
5.7.5.1.3. Microbiological Analyses 27
5.7.5.1.4. TDS 27
5.8 Measurements Outside of the Test/QAPlan Specifications 27
5.8.1 Total Chlorine 27
5.8.2 Temperature 28
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5.8.3 pH 28
Chapter 6 References 29
Chapter 7 Vendor Comments 30
7.1 Section 2.3 Trade Names - Addition 30
7.2 HPC Interference 30
7.3 Conclusion 30
Appendices
Appendix A. Virus and Bacteria Reduction Data
Appendix B. QA/QC Measurements
Appendix C. NSF Drinking Water Systems Laboratory and Chemistry Laboratory Bench
Sheets
Appendix D. Microbiology Laboratory Bench Sheets
Appendix E. NSF LIMS Report
List of Tables
Table 1-1. Virus and Host ATCC Designations 2
Table 3-1. Challenge Schedule for Conditioned Units 13
Table 3-2. Challenge Schedule for Unconditioned Units 15
Table 4-1. Short-Term TDS Reduction Test Results 17
Table 4-2. Virus Log Reduction Data for Unconditioned Units 18
Table 4-3. Virus Log Reduction Data for Conditioned Units 19
Table 4-4. Bacteria Log Reduction Data for Unconditioned Units 21
Table 4-5. Bacteria Log Reduction Data for Conditioned Units 21
Table 4-6. Test Unit Performance Rankings 22
Table 5-1. Completeness Requirements 26
List of Figures
Figure 2-1. Schematic Diagram of the Watts Premier Ultra 5 RO System 7
Figure 2-2. Photograph of the Watts Premier Ultra 5 RO System 8
Figure 3-1. Schematic Diagram of Test Rig 10
Figure 3-2. Test Units Installed on the Test Rig 11
VI
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Abbreviations and Acronyms
ANSI
ASTM
ATCC
°C
CPU
cm
DWS
EPA
ETV
°F
L
mg
ml
nm
NSF
PBDW
PFU
POU
psig
QA
QC
QA/QC
RPD
RO
SOP
IDS
ISA
TSB
Hg
Ml
jam
American National Standards Institute
American Society of Testing Materials
American Type Culture Collection
Degrees Celsius
Colony Forming Unit
Centimeter
Drinking Water Systems
U. S. Environmental Protection Agency
Environmental Technology Verification
Degrees Fahrenheit
Liter
Milligram
Milliliter
Nanometer
NSF International (formerly known as National Sanitation Foundation)
Phosphate-Buffered Dilution Water
Plaque Forming Unit
Point-of-Use
Pounds per Square Inch Gauge
Quality Assurance
Quality Control
Quality Assurance/Quality Control
Relative Percent Deviation
Reverse Osmosis
Standard Operating Procedure
Total Dissolved Solids
Tryptic Soy Agar
Tryptic Soy Broth
Microgram
Microliter
Micrometer
MicroSieman
vn
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Acknowledgments
NSF International was responsible for all elements in the testing sequence, including collection
of samples, calibration and verification of instruments, data collection and analysis, data
management, data interpretation and the preparation of this report.
The Manufacturer of the Equipment was:
Watts Premier Incorporated
1725 West Williams Street
Phoenix, AZ 85027
NSF wishes to thank the members of the expert technical panel for their assistance with
development of the test plan.
Vlll
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Chapter 1
Introduction
1.1 Environmental Technology Verification (ETV) Purpose and Program Operation
The U.S. Environmental Protection Agency (EPA) has created the Environmental Technology
Verification (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; with 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; by
conducting field or laboratory testing, collecting and analyzing data; and by 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 EPA has partnered with NSF International (NSF) under the ETV Drinking Water Systems
(DWS) Center to verify performance of drinking water systems that benefit the public and small
communities. It is important to note that verification of the equipment does not mean the
equipment is "certified" by NSF or "accepted" by EPA. Rather, it recognizes that the
performance of the equipment has been determined and verified by these organizations for those
conditions tested by the FTO.
1.2 Development of Test/Quality Assurance (QA) Plan
As part of the national Homeland Security effort, NSF has developed a test/QA plan under the
EPA ETV program for evaluating point-of-use (POU) reverse osmosis (RO) drinking water
treatment systems for removal of biological contamination agents. This test/QA plan uses
surrogate bacteria and viruses in place of testing with the actual agents of concern.
To assist in this endeavor, NSF assembled an expert technical panel, which recommended the
experimental design and surrogate choices prior to the initiation of testing. Panel members
included experts from the EPA, United States Army, and United States Centers for Disease
Control and Prevention, Division of Parasitic Diseases, as well as a water utility microbiologist,
a university professor, and an independent consultant in the POU drinking water treatment
systems industry.
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By participating in this ETV test, vendors obtain EPA and NSF verified third-party test data
indicating potential user protection against intentional biological contamination of potable water.
POU RO systems are not typically marketed as water purifiers that remove bacteria and viruses
from drinking water, but they may still remove significant numbers of the microorganisms, thus
offering the user a significant level of protection. The verifications serve to notify the public of
the possible level of protection against biological contamination agents afforded to them by the
use of verified systems.
The test/QA plan called for testing ten Watts Premier Ultra 5 units with a standard test water
containing bacterial or viral surrogates. The virus challenges were conducted with the water set
to pH values of 6, 7.5, and 9, while the bacteria challenges were conducted at pH 7.5 only. The
systems were also challenged at both 40 and 80 pounds per square inch, gauge (psig). The test
units were subjected to challenge scenarios that were unique combinations of the challenge
organisms, pH, and inlet water pressure. Five units were challenged immediately after
completion of the manufacturer's installation and conditioning instructions, while the other five
underwent a 25-day conditioning period prior to being challenged with the surrogates.
1.2.1 Bacteria and Virus Surrogates
The expert technical panel recommended that NSF and the EPA use the bacteria Brevundimonas
diminuta (American Type Culture Collection (ATCC) strain 19146, formerly Pseudomonas
diminutd), and Hydrogenophaga pseudoflava (ATCC strain 33668) as surrogates for bacterial
agents. These surrogates were chosen based on their small sizes, as the smallest identified
bacterium of concern can be as small as 0.2 jam in diameter. H. pseudoflava has a minimum
diameter of 0.1 to 0.2 jam, while B. diminuta has a minimum diameter of 0.2 to 0.3 jam (please
note that these minimum diameters were not obtained during this study. See Section 5.4.2 for
discussion). B. diminuta is the accepted bacteria of choice for testing filters and membranes
designed to remove bacteria. It is used in the American Society of Testing Materials (ASTM)
"Standard Test Method for Retention Characteristics of 0.2-|o,m Membrane Filters Used in
Routine Filtration Procedures for the Evaluation of Microbiological Water Quality" (2001).
The virus surrogates were the bacteriophages MS2, Phi X 174, and fr. The ATCC designation
and host Escherichia coli strain for each virus is given Table 1-1.
Table 1-1. Virus and Host ATCC Designations
Virus ATCC Designation Host E. coli ATCC Strain
MS2
Phi X 174
fr
15597-B1
13706-B1
15767-B1
15597
13706
19853
The expert technical panel recommended these viruses based on their small sizes and isoelectric
points. The isoelectric point is the pH at which the virus surface is neutrally charged. MS2 is 24
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nm in diameter with an isoelectric point at pH 3.9, Phi X 174 is 27 nm in diameter with an
isoelectric point at pH 6.6, and fr is 19 nm in diameter with an isoelectric point at pH 8.9. With
varying isoelectric points, the viruses have different surface charges, or different strengths of
negative or positive charge, depending on the pH. In solutions above the isoelectric point, the
virus is negatively charged. Below the isoelectric point, the virus is positively charged. Using
different pH settings for the virus challenges allowed an evaluation of whether electrostatic
forces enhance virus retention in mechanical filtration scenarios. The pH 6 and 9 settings were
chosen because they are just beyond the upper and lower boundaries for allowable pH in the
EPA National Secondary Drinking Water Regulations. The pH 7.5 setting was chosen because it
is the midpoint between the boundaries.
The bacteria reduction challenges were performed only at pH 7.5, because the expert panel
believed that bacteria cell size and mass are too large for electrostatic interactions to play a
significant role.
1.2.2 Inlet Pressure
The bacteria and virus challenge tests were performed at dynamic inlet pressures of both 40 and
80 psig to evaluate whether inlet pressure affects microorganism rejection by RO membranes.
Forty psig is a worse case scenario for ionic rejection mechanisms, while 80 psig represents a
poorer mechanical filtration scenario. In a typical mechanical filtration scenario, the higher
pressure could push suspended particles further into, and perhaps all the way through, the
filtration media, and it could also distort seals to the point that they leak. However, this may or
may not be the case with RO membranes, since they operate by a different principle.
1.2.3 Long-Term Conditioning
The expert technical panel was presented with anecdotal evidence that RO membrane
performance could be erratic for approximately the first month of operation, so they
recommended that NSF split the test units into two groups, one group to be tested immediately
after installation and completion of the manufacturer's conditioning instructions (hereafter
referred to as "unconditioned units"), and a second group to be tested after a 25 working day
conditioning period (hereafter referred to as "conditioned units").
1.3 Testing Participants and Responsibilities
The ETV testing of the Watts Premier Ultra 5 RO system was a cooperative effort between the
following participants:
NSF
Watts Premier
EPA
The following is a brief description of each of the ETV participants and their roles and
responsibilities.
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1.3.1 NSF
NSF is a not-for-profit organization dedicated to public health and safety, and to the protection of
the environment. Founded in 1946 and located in Ann Arbor, Michigan, NSF has been
instrumental in the development of consensus standards for the protection of public health and
the environment. The EPA partnered with NSF to verify the performance of drinking water
treatment systems through the EPA's ETV Program.
NSF performed all verification testing activities at its Ann Arbor location. NSF prepared the
test/QA plan, performed all testing, managed, evaluated, interpreted, and reported on the data
generated by the testing, and reported on the performance of the technology.
Contact Information:
NSF International
789 N. Dixboro Road
Ann Arbor, MI 48105
Phone: 734-769-8010
Fax: 734-769-0109
Contact: Bruce Bartley, Project Manager
Email: bartley@nsf.org
1.3.2 Watts Premier
The verified system is manufactured by Watts Premier, a division of Watts Water Technologies.
Watts Premier manufactures industrial, food service, point-of-entry, and point-of-use water
treatment systems.
The manufacturer was responsible for supplying the RO systems in accordance with the
equipment selection criteria given in Section 3.1.1, and for providing logistical and technical
support as needed.
Contact Information:
Watts Premier Incorporated
1725 West Williams Drive, C-20
Phoenix, AZ 85027
Phone: 800-752-5582
Fax:623-931-0191
Contact Person: Mr. Bob Maisner
Email: maisnerr@wattsind.com
1.3.3 U.S. Environmental Protection Agency
The EPA, through its Office of Research and Development, has financially supported and
collaborated with NSF under Cooperative Agreement No. R-82833301. This verification effort
was supported by the DWS Center operating under the ETV Program. This document has been
peer-reviewed and reviewed by NSF and EPA, and recommended for public release.
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Chapter 2
Equipment Description
2.1 RO Membrane Operation
Membrane technologies are among the most versatile water treatment processes with regard to
their ability to effectively remove the widest variety of contaminants at the lowest costs. RO
membranes operate by the principal of cross-flow filtration. In this process, the influent water
flows over and parallel to the filter medium and exits the system as reject water. Under pressure,
a portion of the water in the bulk solution diffuses through the membrane becoming "permeate".
Membrane pore sizes are small enough to reject bacteria and viruses, but the organisms may still
pass through imperfections in the membrane, or pass around the membrane due to microscopic
leaks in the seals
2.2 Equipment Capabilities
The Watts Premier Ultra 5 system is certified by NSF to NSF/ANSI Standard 58 - Reverse
Osmosis Drinking Water Treatment Systems. The system has a certified production rate of 9.06
gallons per day, and an efficiency rating of 8.35%. Efficiency rating as defined in NSF/ANSI
Standard 58 is "a percentage measure of the amount of influent water that is delivered as
permeate under a closed permeate discharge set of actual use conditions." These measurements
are based on system operation at 50 psig inlet pressure, a water temperature of 77 °F, and a total
dissolved solids (TDS) level of 750 mg/L. The amount and quality of treated water produced
varies depending on the inlet pressure, water temperature, and level of TDS. These
measurements were not subject to verification during this study.
2.3 Trade Names
The Ultra 5 is sold under different names at various retail outlets. All of the following models
are identical to the Ultra 5 except in name:
- RO-TFM-5SV
- PUR-TEK
- WATTS-25
- CRO-TFM-5SV
- WATTS PURE WATER RO-5
- DELUXE PLUS
- DELUXE
- AQUA-RITE 5.0
2.4 System Components
The Ultra 5 is a five-stage treatment system. The inlet water first passes through a sediment
filter, and then through two sequential carbon block filters. The fourth stage is passage through
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the RO membrane element. The permeate is sent to a three gallon maximum capacity storage
tank, and the reject water is sent to a drain. The system has an automatic shut-off valve to shut
down the flow of water through the system when the storage tank is nearly full. The fifth stage
of treatment is a granular activated carbon filter downstream of the storage tank. A schematic
drawing of the system is provided in Figure 2-1, and a photo of the system in Figure 2-2.
2.5 System Operation
When the flow of water into the system is started, it will continually produce treated water until
the storage tank is nearly full. When the storage tank is almost full, back-pressure causes an
automatic shut-off device to activate, stopping the flow of water into the system. After a portion
of the product water is dispensed from the storage tank, the shut-off device deactivates, allowing
water to again flow into the system until the storage tank is nearly full. The operational capacity
of the storage tank will vary slightly from unit to unit, and is also affected by the inlet water
pressure.
2.6 Rate of Waste Production
The Ultra 5 system produces approximately 11 gallons of reject water for each gallon of product
water produced, as defined by the efficiency rating parameter in NSF/ANSI Standard 58.
2.7 Equipment Operation Limitations
Watts Premier gives the following limitations for the drinking water to be treated by the system:
• temperature of 40 - 100°F;
• pressure of 40 - 100 psig;
• pHof3-ll;
• Non-detectable iron level;
• hardness of more than 120 mg/L may reduce membrane life expectancy; and
• TDS level should be less than 1800 mg/L.
2.8 Operation and Maintenance Requirements
Watts Premier recommends the following maintenance steps:
• Replacement of the filters upstream from the RO membrane every 6 months;
• Replacement of the carbon filter located downstream of the storage tank annually;
• Annual sanitization of the system with hydrogen peroxide;
• Replacement of the membrane every two to five years, depending on the quality of the
product water (Watts Premier offers free water testing, or a TDS monitor for purchase, to
monitor the product water quality); and
• Periodic storage tank air pressure check.
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Figure 2-1. Schematic Diagram of the Watts Premier Ultra 5 RO System
R*v 1/31/02
* The reverse osmosis system contains a replaceable treatment component, critical for the effective reduction of total
dissolved solids and that the product water shall be tested periodically to verify that the system is performing properly
ltem#
1 a
1 b
2
3 a
3 b
4 a
4 b
5 a
5 b
6 a
6 b
7
8 a
8 b
8 c
9 a
9 b
10 a
10 b
11
12
13
14
15
Part*
100004
100014
104017
101009
100036
110004
110005
113004
113007
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113024
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116001
116002
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119004
119007
122004
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125002
125005
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Description
GAC-IL-6"-1/4F(1M-6)
GAC-IL-10M-1/4 F (PREMIER)
SED-SPUN-10"-5M-CTG(5M-10)
CARBON BLOCK-10"-5M-CTG
GAC 10"-56CulnCPG
•MEM-TFM-18GPD
•MEM-TFM-25 GPD-DRY
LID-BLACK 1/4" FPT UNASSEMBLED
LID-WHITE 1/4" FPT UNASSEMBLED
HOUSING-FILTER 10" BLUE
HOUSING-FILTER 10" WHITE
VESSEL-MEM-HOUSING-RES
FAUCET-AG-CHROME (TF)
FAUCET-AG-WAVE BLK ON SS
FAUCET-AG-WAVE WHT ON SS
TANK-PRES-3 GAL-BLUE
TANK-PRES-3 GAL WHITE
FLOW RESTRICTOR 150 ML
FLOW RESTRICTOR 250 ML
NUT-PL-1/4C-WHITE-CELCON
NUT-PL-1/4C-BLACK-NYLON
CON-PL-1/4CX1/4M
ELB-PL-1/4CX1/8M-90
ELB-PL-1/4CX1/4M-90
Item*
16
17
18
19
20
21
22
23 a
24
25 a
25 b
26
27
28
29
30
31
32
33
34
35
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Part*
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131002
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134007
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Description
UNI-PL-1/4CX1/4C
NUT-BR-1/4C"
SLEEVE-DELRIN-1/4"
INSERT-BR-1/4"
HEX NIPPLE-BR-1/4 HEAVY DUTi
TEE-TANK-BR-1/4CX1/4CX1/4F
VALVE-SHUT OFF 1/4MPT (RES.)
VALVE-ADAPTA VALVE
VALVE-CHECK-PLA-ELBOW1/4CX1/8M
BRACKET-4SV-STEEL-WHITE
BRACKET-5SV-STEEL-WHITE
SCREW-4M 0-3/4" PHIL PANHEAD
SCREW-#10-1" PHIL PANHEAD
CLIP-MTG-MEM-VESSEL
CLIP-DOUBLE-MEM TO IL (OPTIONAL)
DRAIN SADDLE 3/8"
TANK STAND
0-RING FILTER HOUSING
MANUAL 4SV & 5SV PR-14
GREEN TUBING
BLACK TUBING
BLUE TUBING
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Figure 2-2. Photograph of the Watts Premier Ultra 5 RO System
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Chapter 3
Methods and Procedures
3.1 Test Equipment
3.1.1 Equipment Selection
Equipment selection criteria were developed to ensure that the test units were representative of
product variability. Watts Premier supplied ten units from three different production runs. The
RO membranes themselves were also chosen to be representative of product variability. All
membranes are quality control (QC) tested for TDS rejection performance by the membrane
manufacturer. Six membranes were chosen from the middle of the allowable QC performance
range as specified by Watts Premier, two were chosen from the high end of the QC performance
range, and the last two were chosen from the lower end. Note that the actual QC values used by
the manufacturer to establish the range of allowable performance are confidential, and so are not
reported. The ten systems were split into two groups of five as discussed in Section 1.2.3, such
that each group had one high end and one low end membrane, and three membranes from the
middle range.
3.1.2 Test Unit Configuration
The Ultra 5 is sold as a five-stage treatment system, as described in Section 2.4. However, for
the tests described in this report, all filter elements other than the RO membrane were removed
from the units. The pre-membrane and post-membrane filters do not have pore sizes small
enough to remove bacteria or viruses, but could temporarily retain significant numbers of the
organisms through electrostatic interactions, giving a positive bias to the performance data.
Otherwise the systems were operated as sold to the consumer.
3.2 Verification Test Procedure
3.2.1 Test Rig
Each group of five test units was plumbed to a single test station. The test rig used a 500-gallon
polyethylene tank to hold the influent challenge water. See Figure 3-1 for a schematic diagram.
Please note that the units of each group of five were attached to the rig such that all were
plumbed to the same influent feed line. Figure 3-2 shows one group of the test units installed on
the test rig.
3.2.2 Test Rig Sanitization
The test apparatus was sanitized with a sanitization agent prior to the beginning of each test to
keep the heterotrophic bacteria population to a minimum. After sanitization, the test apparatus
was flushed until a less-than-detectable concentration of sanitizing agent was present.
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Figure 3-1. Schematic Diagram of Test Rig
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NOTE 2- Faucet-attached systems and portable systems shall be placed after solenoid valves B and C.
NOTE 3- Solenoid valves shall be controlled by appropriate timer(s).
NOTE 4- Pressure gauges shall be located directly ahead of test units.
NOTE 5- Diameter of plumbing and equipment after test units shall not be less than the diameter at the connection to the unit.
Product water
sampling points
3.2.3 Test Water
3.2.3.1 Base Water
Ann Arbor, Michigan municipal drinking water was deionized to make the base water for the
tests. The base water had the following constraints:
• Conductivity < 2 [iS/cm at 25 °C;
• Total organic carbon < 100 |J,g/L; and
• Heterotrophic bacteria plate count < 10,000 colony forming units (CFU)/100 ml.
The base water was then adjusted to meet the following characteristics:
• Total chlorine < 0.05 mg/L;
• Addition of sodium bicarbonate to achieve an alkalinity (expressed as calcium carbonate)
of 100 ± 5 mg/L prior to pH adjustment;
• pH adjustment with hydrochloric acid or sodium hydroxide to reach a value of 6.0 ± 0.5,
7.5 ± 0.5, or 9.0 ± 0.5 as required by the challenge schedule*; and
• Temperature of 20 ± 2.5 °C.
*Note that the lab technicians experienced difficulty maintaining the pH below 6.5 or above 8.5. See section 4.2.3
and 5.7.5.1.2 for more discussion.
10
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The test water for each challenge was made in 200-gallon volumes. In addition to the above
characteristics, total hardness, TDS, and turbidity were measured daily.
Figure 3-2. Test Units Installed on the Test Rig
3.2.3.2 Bacteria and Virus Challenges
The viruses were purchased from Biological Consulting Services of North Florida, and the
bacteria from ATCC. The viruses were purchased in adequate volumes so that the suspensions
received were added directly to the test water. The bacteria were cultivated at NSF to obtain the
challenge suspensions. Section 3.3.2.3 describes the method used to create the bacteria
challenges.
The targeted influent challenge concentrations for the bacteria were IxlO5 CPU of bacteria per
100 milliliters, or greater. The targeted influent challenge concentration for the viruses was
IxlO4 plaque forming units (PFU) of virus per milliliter, or greater. Phi X 174 is more difficult
to cultivate, and so was supplied at lower concentrations than the other viruses. The suspensions
11
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received for the conditioned units were too low to cost effectively obtain the target challenge
level (3.6xl06 PFU/ml, vs. 6.7xl09 PFU/ml for fr and 2.4xlOn PFU/ml for MS2), so the
challenge levels were on the order of 103 PFU/ml. The suspensions received for unconditioned
units were more concentrated, at 3.7xl08 PFU/ml, so the target challenge level was exceeded.
See Appendix A for the measured influent challenge levels.
The test units were challenged with each bacteria separately, but all three viruses were mixed
together for each virus challenge. After addition of the challenge organism to the base test water,
the resultant challenge water was mixed for a minimum of 30 minutes using a recirculation pump
prior to beginning the test.
3.2.4 Test Unit Operation
3.2.4.1 Test Unit Installation
All test units were installed and conditioned in accordance with Watts Premier's instructions
using the base test water described above at pH 7.5 ± 0.5. The conditioning instructions called
for operating each unit continuously until its storage tank was full. The operation time to fill the
tank varied from unit to unit, but was on average approximately six hours. After this
conditioning period, an effluent sample was collected from each unit as a negative control and
analyzed for the challenge organisms.
3.2.4.2 TDS Reduction System Check
After completion of Watts Premier's conditioning procedure, the test units underwent a one-day
TDS reduction test using the test protocol in NSF/ANSI Standard 58. The Standard 58 test was
modified so that the units were operated continuously for one tank-fill period. Product water
samples were then collected from each storage tank and analyzed for TDS. This test ensured that
the products undergoing verification testing were representative of the expected performance of
the system, and that there were no membrane integrity or membrane seal problems.
The units receiving 25 days of conditioning were tested for TDS reduction prior to the initiation
of the conditioning period. The unconditioned units were tested after completion of all of the
bacteria and virus challenges due to an error in scheduling the testing sequence.
3.2.4.3 Long-Term Conditioning
The five units receiving long-term conditioning were tested first. They were operated using the
test water without surrogate organisms for a period of 25 working days prior to challenge testing.
On each day the units were operated continuously at a dynamic inlet pressure of 80 ± 3 psig for
one tank-fill period. The units then sat idle overnight under pressure, and the tanks were emptied
the next morning prior to resumption of unit operation.
12
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3.2.4.4 Conditioned Units Challenge Testing
Following the conditioning period, the units were challenged according to the schedule in Table
3-1. Prior to the start of the challenge schedule, the test rig was sanitized again as described
above in Section 3.2.2. The test units were taken off-line to prevent sanitizer from entering
them, and the test rig was flushed free of sanitizer before they were reconnected to the rig.
At the end of the day before each challenge, the base test water was prepared as described in
Section 3.2.3.1. The morning of the challenge, the pH was checked and adjusted, if necessary,
and the bacteria or viruses were added as described in Section 3.2.3.2.
The dynamic inlet water pressure for operation was set at either 40 ± 3 or 80 ± 3 psig according
to the challenge schedule.
An influent sample was collected each day at the time test unit operation started. Each test unit
was then operated continuously for one tank-fill period (approximately six to eight hours). In a
couple of cases during the 40 psig challenge periods, the lab technician manually shut-off the
water supply to a unit because the shut-off device did not activate after approximately nine hours
of operation due to the low inlet pressure.
At 40 psig, approximately two gallons of treated water was produced before shut-off, while at 80
psig, approximately three gallons were produced.
After each unit shut off, its storage tank was emptied into a sterile container, and a sub-sample
was collected for challenge organism enumeration. The sub-sample volumes were one liter for
the bacteria challenges, and 150 ml for virus challenges. A second influent sample was collected
after all units ceased operation. All samples were collected in sterile polypropylene bottles, and
were enumerated in triplicate.
Following each day's challenge period, the systems were operated for one tank-fill cycle using
the test water without any test organisms present. This served to flush the systems in-between
challenge periods. The units rested overnight under pressure, and the storage tanks were emptied
the next morning prior to initiation of that day's challenge.
Table 3-1. Challenge Schedule for Conditioned Units
Day Challenge Organism(s) pH Inlet Pressure (psig)
1
2
3
4
5
6
7
8
9
10
All Viruses
All Viruses
All Viruses
All Viruses
All Viruses
All Viruses
H. pseudoflava
H. pseudoflava
B. diminuta
B. diminuta
6.0 ±0.5
6.0 ±0.5
7.5 ±0.5
7.5 ±0.5
9.0 ±0.5
9.0 ±0.5
7.5 ±0.5
7.5 ±0.5
7.5 ±0.5
7.5 ±0.5
40 ±3
80 ±3
40 ±3
80 ±3
40 ±3
80 ±3
80 ±3
40 ±3
40 ±3
80 ±3
13
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3.2.4.5 Unconditioned Units Testing
Challenge testing for the unconditioned units began immediately after completion of the
manufacturer's conditioning instructions. The testing schedule is given below in Table 3-2.
Only four units were tested for this group because one of the units did not operate properly. The
automatic shutoff device was hooked-up incorrectly, causing the influent water to flow directly
into the storage tank. This problem was not noticed until the first day of challenge testing, so the
storage tank was contaminated before it could be corrected.
At the end of the day before each challenge, the base test water was prepared as described in
3.2.3.1. The morning of the challenge, the pH was checked and adjusted, if necessary, and the
bacteria or viruses were added as described in Section 3.2.3.2.
The dynamic inlet water pressure for operation was set at either 40 ± 3 or 80 ± 3 psig according
to the challenge schedule.
Many heterotrophic bacteria were observed on the effluent sample agar plates from the
conditioned units bacteria challenge testing, which made counting the challenge organism
colonies more difficult. The influent samples had very low levels of heterotrophic bacteria due
to the sanitization of the test rigs, but the test units could not be sanitized in the same way. To
evaluate whether the heterotrophic bacteria populations would be lower in the unconditioned
units, since they were being tested only a couple days after being installed on the test rigs, the
bacteria reduction tests were carried out first for this set of units. During testing of both the
conditioned units and unconditioned units, heterotrophic bacteria counts up to 106 CFU/lOOml
were observed in the effluent samples, so the timing of the bacteria challenge tests did not appear
to make a difference. See Section 5.4.4 for more discussion about heterotrophic bacteria.
An influent sample was collected each day at the time test unit operation started. Each test unit
was then operated continuously for eight hours, or the time to fill the storage tank, whichever
came first. An eight-hour maximum operation period was instituted for this group because of the
observed operation times at 40 psig during the conditioned units challenge period. As each unit
shut off, its storage tank was emptied into a sterile container, and a sub-sample was collected for
challenge organism enumeration. The sub-sample volumes were one liter for the bacteria
challenges, and 150 ml for virus challenges. A second influent sample was collected after all
units ceased operation. All samples were collected in sterile polypropylene bottles, and
enumerated in triplicate.
Following each challenge period, the systems were operated for one tank-fill period using the
test water without any test organisms present. This served to flush the systems in between
challenge periods. The units rested overnight under pressure, and the storage tanks were emptied
the next morning prior to initiation of that days challenge period.
14
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Table 3-2. Challenge Schedule for Unconditioned Units
Day Challenge Organism(s) PH Inlet Pressure (psig)
1
2
o
J
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
3.3 Analytical Methods
3.3.1 Water Quality Analytical Methods
The following are the analytical methods used during verification testing. All analyses followed
procedures detailed in NSF Standard Operating Procedures (SOP).
• pH - All pH measurements were made with an Orion Model SA 720 meter. The meter
was operated according to the manufacturer's instructions, which are based on Standard
Method 4500-H+.
• Temperature - Water temperature was measured using an Omega model HH11 digital
thermometer.
• TDS - TDS for the TDS reduction system check test was measured through conductivity
according to Standard Method 2510. An Oakton pH/Conductivity 510 Series meter was
used to analyze the samples from the conditioned units. The samples from the
unconditioned units were measured using a Fisher Scientific Traceable™ Conductivity
Meter. The Fisher meter was purchased between the two sets of challenges, replacing the
Oakton meter.
• Total Chlorine - Total chlorine was measured according to Standard Method 4500-C1 G
with a Hach Model DR/2010 spectrophotometer using AccuVac vials.
3.3.2 Microbiology Methods
3.3.2.1 Sample Processing, and Enumeration of Viruses
The viruses were enumerated using a double agar layer method published in NSF/ANSI Standard
55 - Ultraviolet microbiological water treatment systems, for enumerating MS2. This method is
similar to the double agar layer method in EPA Method 1601.
Four to eighteen hours prior to sample processing, 100 jol of the appropriate host E.coli
suspension was pipetted into a fresh 10 ml of Tryptic Soy Broth (TSB), and incubated at 35 °C.
After incubation, 100 \A volumes of the resulting E. coli culture were transferred to sterile,
capped test tubes.
15
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All samples were enumerated in triplicate. All samples were serially diluted for enumeration,
and the effluent samples were also enumerated directly. One ml volumes of the sample or
dilution were pipetted into the E. coli suspension test tubes. The tubes were vortexed for a
minimum of 30 seconds to "mate" the bacteria and virus, and then 4 ml of molten, tempered TSB
plus 1% agar was added to each tube. These mixtures were then poured over Tryptic Soy Agar
(TSA) plates, and allowed to solidify. The plates were incubated at 35°C for 18-24 hours. Viral
plaques were counted using a Quebec Colony Counter.
3.3.2.2 Bacteria Cultivation
The bacteria were purchased from ATCC and rehydrated with nutrient broth. After 48 hours of
incubation at 30 °C, tubes containing 10 mL of TSB were inoculated with 100 |jL of the nutrient
broth suspension. These tubes were incubated for 48 hours at 30 °C. After this incubation
period, 100 |jL of these suspensions were pipetted into new tubes containing 10 mL of fresh
TSB. These tubes were then also incubated for 48 hours at 30 °C. This process was repeated at
least three times, up to a maximum of 30 times.
3.3.2.3 Preparation of Bacteria Challenge Suspensions
To obtain the challenge suspensions, 1 mL of a 48-hour TSB culture was pipetted onto an
appropriate number of TSA slants. The slants were inoculated at 30 °C for 48 hours. After
inoculation, 5 mL of sterile phosphate buffered dilution water (PBDW) was pipetted onto each
slant, and the agar surfaces were scraped to suspend the cells. The suspensions were then
pipetted out of the slants into an appropriate volume of PBDW. The resulting challenge
suspension was vortexed for approximately 30 seconds to disperse the cells. The challenge
suspensions were refrigerated and added to the tank of test water within one hour. Samples of
the challenge suspension were collected and enumerated according to the method in 3.3.2.4.
3.3.2.4 Bacteria Sample Processing and Enumeration
All samples were enumerated in triplicate using a membrane filtration method based on Standard
Method 9215 D. All samples were serially diluted for enumeration with sterile PBDW, and the
effluent samples were also enumerated directly. One milliliter volumes of the influent sample
dilutions, and 100 ml volumes of either the effluent samples or dilution were pipetted into sterile
vacuum filtration apparatuses, 25 ml of sterile PBDW added, and the suspension vacuum filtered
through sterile 0.1 jam membrane filters. The funnels were then rinsed three times with
approximately 5 ml of PBDW, and the rinse water also suctioned through the filters. The
membrane filters were aseptically removed from the apparatuses and placed onto R2A agar
plates. The plates were incubated at 30°C for 48 hours. Characteristic B. diminuta or H.
pseudoflava colonies were enumerated with a Quebec Colony Counter.
16
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Chapter 4
Results and Discussion
4.1 TDS Reduction
The performance data from the TDS reduction system check test described in 3.2.4.2 are
presented below in Table 4-1. Watts Premier's reported TDS reduction performance for the
Ultra 5 is 96.8%, so the units tested are representative of expected membrane performance.
Table 4-1. Short-Term TDS Reduction Test Results
Unconditioned Units
TDS Percent
(mg/L) Reduction
Influent
Effluents:
Unitl
Unit 2
Units
Unit 4
790
28
32
29
23
96%
96%
96%
97%
Conditioned units
TDS Percent
(mg/L) Reduction
Influent
Effluents:
Unitl
Unit 2
Unit3
Unit 4
Unit5
750
39
33
37
30
35
95%
96%
95%
96%
95%
4.2 Virus Reduction
The virus Iog10 reduction data for each challenge scenario are presented below in Tables 4-2 and
4-3. The influent and effluent virus PFU count data for each individual test unit are given in
Appendix A. The triplicate influent and effluent counts in Appendix A were averaged by
calculating geometric means. The means were then Iog10 transformed and Iog10 reduction values
calculated for each test unit.
Please note that the "non-detect" effluent counts of < 1 PFU/ml were treated as 1 PFU/ml for
geometric mean calculations. Also, if the triplicate enumeration yielded two counts of < 1
PFU/ml and only one count above the detection limit, the geometric mean is footnoted to
indicate this.
17
-------
Table 4-2. Virus Log Reduction Data for Unconditioned Units
Challenge Conditions
Target Actual Pressure Challenge
pH
6.0 ±0.5
6.0 ±0.5
7.5 ±0.5
7.5 ±0.5
9.0 ±0.5
9.0 ±0.5
pH (psig) Organisms
6.5 40 fr
MS2
Phi X 174
6.2 80 fr
MS2
Phi X 174
7.6 40 fr
MS2
Phi X 174
7.7 80 fr
MS2
Phi X 174
8.7 40 fr
MS2
Phi X 174
9.0 80 fr
MS2
Phi X 174
Log10
Influent
Challenge
6.3
6.1
5.0
5.9
5.8
4.9
5.9
5.6
5.7
5.8
5.7
5.9
5.8
5.6
5.7
6.0
5.7
5.6
fr mean3
MS2 mean3
Phi X 174 mean3
i
2
3
The arithmetic mean of all test units
Triplicate count had two
Geometric Mean Lo
Unitl
4.8
5.62
5.0
4.5
4.5
4.62
4.0
3.8
3.7
4.6
4.4
4.3
4.4
4.1
3.8
4.6
4.7
4.1
4.5
4.5
4.3
Unit 2
3.1
3.0
2.4
3.2
3.0
2.8
2.9
2.7
2.3
2.5
2.6
2.6
2.9
2.7
2.6
3.5
3.4
3.5
3.0
2.9
2.7
for each challen
Unit3
2.9
2.8
2.3
3.3
3.3
2.4
4.9
5.0
5.72
4.3
4.3
3.7
4.2
4.1
3.3
3.7
3.8
3.5
3.9
3.9
3.5
ge.
gio Reduction
Unit 4
4.6
4.7
5.02
5.9
5.8
4.9
4.4
4.3
4.3
5.5
5.42
5.1
4.8
4.8
4.1
5.1
5.1
4.5
5.1
5.0
4.7
Mean1
3.8
4.0
3.7
4.2
4.2
3.7
4.1
4.0
4.0
4.2
4.2
3.9
4.1
3.9
3.5
4.2
4.3
3.9
4.1
4.1
3.6
Log10
Mean
Effluent
Count
2.5
2.1
1.3
.7
.6
.2
.8
.6
.7
.6
.5
2.0
1.7
1.7
2.2
.8
.4
.7
.9
.7
.7
"non-detect" agar plates.
18
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Table 4-3. Virus Log Reduction Data for Conditioned Units
Challenge Conditions Logic
Target Actual Pressure Challenge Influent
pH pH (psig) Organisms Challenge
6.0 ±0.5 6.5
6.0 ±0.5 6.4
7.5 ±0.5 7.5
7.5 ±0.5 7.3
9.0 ±0.5 8.9
9.0 ±0.5 7.93
40 fr
MS2
Phi X 174
80 fr
MS2
Phi X 174
40 fr
MS2
Phi X 174
80 fr
MS2
Phi X 174
40 fr
MS2
Phi X 174
80 fr
MS2
Phi X 174
5.1
4.8
3.4
6.1
6.0
3.8
6.4
6.2
4.0
6.3
6.1
4.1
6.2
5.8
4.1
6.0
5.9
4.0
fr mean4
MS2 mean4
Phi X 174 mean4
Geometric Mean Logic Reduction
Unit 1 Unit 2 Unit 3 Unit 4 Unit 5 Mean1
3.6
3.2
3.4
4.6
4.6
3.8
4.2
4.2
3.7
4.8
5.2
4.1
4.4
4.2
4.1
4.4
4.3
4.0
4.3
4.3
3.9
4.1
3.7
3.4
4.2
4.2
3.8
4.8
4.5
4.02
5.6
5.5
4.12
4.2
4.0
4.1
4.9
5.9
4.0
4.6
4.6
3.9
4.0
3.8
3.4
4.3
4.2
3.8
4.7
4.8
4.02
5.6
5.6
4.1
4.3
4.2
4.1
4.7
4.8
4.0
4.6
4.6
3.9
4.8
4.1
3.4
4.7
4.8
3.8
4.8
4.7
4.0
5.3
4.9
4.1
4.3
4.1
4.1
4.7
4.9
4.0
4.8
4.6
3.9
4.0
3.2
3.4
4.6
3.7
3.8
4.2
4.3
3.7
4.8
5.0
4.12
4.3
4.2
4.1
4.6
4.6
4.0
4.4
4.2
3.9
4.1
3.6
3.4
4.5
4.3
3.8
4.5
4.5
3.9
5.2
5.2
4.1
4.3
4.1
4.1
4.7
4.9
4.0
4.6
4.4
3.9
Log10
Mean
Effluent
Count
1.0
1.2
0.0
1.6
1.7
0.0
1.9
1.7
0.1
1.1
0.9
0.1
1.9
1.7
0.0
1.3
1.0
0.0
1.5
1.4
0.0
The arithmetic mean of all test units for each challenge.
2 Triplicate count had two "non-detect" agar plates.
3 See Section 5.8.3 for discussion of pH variance.
4 The arithmetic mean for all challenges against each test unit.
As discussed in Section 3.2.3.2, the Phi X 174 influent challenges for the conditioned units did
not consistently exceed the desired minimum challenge level of IxlO4 PFU/ml (4.0 logs).
Furthermore, the effluent counts were almost all < 1 PFU/ml, so the Iog10 reductions were capped
at 3.4 to 4.1. These data, then, represent a minimum level of performance for the Ultra 5 in
regards to Phi X 174 reduction. The Phi X 174 influent levels for the unconditioned units did
exceed the desired minimum challenge level, and effluent counts at 1 PFU/ml or greater were
recorded in all but one case (unit 4 at pH 6 and 80 psig).
19
-------
4.2.1 Unconditioned Scenario versus Conditioning Scenario
An evaluation of the virus reduction data shows that overall, the conditioned units performed
better than the unconditioned units. The mean logio reductions and mean logio effluent counts
are shown in the bottom right corners of Tables 4-2 and 4-3. A comparison of the mean logio
effluent counts for the unconditioned versus the conditioned units shows that the conditioned
units performed approximately 0.3 to 1.7 logio better than the unconditioned units. However, the
unit-to-unit performance variation for the unconditioned units is wider than for the conditioned
units. Units 1 and 4 consistently performed as well as the conditioned units, while units 2 and 3
did not.
These data indicate that for the Watts Premier Ultra 5, either the systems give better or more
consistent performance with 25 days of conditioning, perhaps due to biofilm and/or scale buildup
on the membranes that serves to partially plug the membrane pore structure, or that units 2 and 3
of the unconditioned group simply did not perform as well as the other seven.
4.2.2 Inlet Pressure Influence
As described in Section 1.2.2, the test units were evaluated at both 40 and 80 psig inlet pressure.
For the conditioned units, there seemed to be a significant increase in performance at 80 psig for
fr and MS2 reduction. Many of the logio reduction numbers at 80 psig are more than 0.5 logs
greater than for the corresponding 40 psig challenge. This trend was not as evident for the
unconditioned units. Again, this could possibly be due to the more inconsistent performance of
this group.
4.2.3 Performance Comparison at Different pH Settings
The test units were also evaluated at three different pH settings: 6.0 ± 0.5, 7.5 ± 0.5, and 9.0 ±
0.5. However, the pH of the challenge water was not measured at the end of each challenge
period as required in the test/QA plan. As a result, the degree of pH drift could not be
determined. Subsequent testing has shown significant pH drift does occur, because the water
chemistry gives it low buffering capacity. Furthermore, the required pH value of 9.0 ± 0.5 was
not obtained for the conditioned units virus challenge testing at pH 9 and 80 psig. The measured
pH was only 7.9. Therefore, no confident comparisons could be made, nor conclusions drawn
about the effect of pH on virus rejection. Inability to maintain the pH in the test water will be
addressed in the next revision of the generic test/QA plan.
4.3 Bacteria Reduction
Presented in Tables 4-4 and 4-5 are the log reduction data for the bacteria challenge portion of
the verification test. The influent and effluent bacteria count data for each individual test unit is
given in Appendix A. As was done for the viruses, the triplicate influent and effluent counts
were averaged by calculating geometric means. The means were then logio transformed and logio
reduction values were calculated for each test unit.
20
-------
Table 4-4. Bacteria Log Reduction Data for Unconditioned Units
Log: o Influent Geometric Mean Logi 0 Reduction
Pressure Challenge Challenge (log/100 ml)
pH (psig) Organisms (log/100 ml) Unit 1 Unit 2 Unit 3 Unit 4
7.5
7.5
40 H. pseudoflava
B. diminuta
80 H. pseudoflava
B. diminuta
6.9
8.2
6.9
8.1
4.4
8.2
4.6
3.5
4.9
3.0
6.6
2.2
2.2
2.0
1.9
3.3
1.6
8.2
3.0
8.1
Table 4-5. Bacteria Log Reduction Data for Conditioned Units
Pressure
pH (psig)
7.5 40
7.5 80
Log10
Influent
Challenge Challenge
Organisms (log/100 ml)
H. pseudoflava
B. diminuta
H. pseudoflava
B. diminuta
6.7
8.3
6.7
8.4
Geometric Mean Logic Reduction
(log/100 ml)
Unitl Unit 2 Unit 3 Unit 4 Unit 5
6.7
8.3
6.7
8.4
6.7
8.3
6.7
8.4
6.7
8.3
6.7
8.4
6.7
7.2
6.7
8.4
6.7
8.3
6.7
8.4
The bacteria data also indicates that conditioning stabilizes and/or improves performance. All
effluent counts for the conditioned units were non-detect for both bacteria, except for unit 4 for
B. diminuta reduction at pH 7.5 and 40 psig. In contrast, for the unconditioned units there were
13 cases out of 16 where the challenge bacteria were detected in the effluents. In addition, the
performance varied from day to day as also observed for the virus challenges. For instance, unit
2 performed well during the H. pseudoflava challenges, with 4.9 and 6.6 logic reductions, but this
unit did not perform as well during the B. diminuta challenges, with reductions of only 2.0 and
3.3 logio In contrast, unit 4 performed much better at B. diminuta reduction (8.1 and 8.2 logic)
than at H. pseudoflava reduction (1.6 and 3.0 Iog10). These results are puzzling, since the two
challenge organisms are similar in size.
Because of the highly variable data from the unconditioned units, and the frequent cases of
nondetectible effluent counts for the conditioned units, no influent pressure comparison is
possible
4.4 Unit-To-Unit Variability
To assess performance between units, and for the same unit through the challenge period, the
performance of the unconditioned units was ranked for each challenge organism. The TDS
reduction results were also ranked to provide a comparison. The rankings are presented below in
Table 4-6. The conditioned units were not ranked, since there was little performance variation
from unit to unit, as can be seen in Table 4-3, and all but one bacteria reduction effluents were at
undetectable levels.
21
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Table 4-6. Performance Rankings for the Unconditioned Test Units
Unitl
Unit 2
Units
Unit 4
H. pseudoflava
Reduction
2
1
4
o
J
B. diminuta
Reduction
2
o
5
4
1
fr
Reduction
2
4
3
1
MS2
Reduction
2
4
3
1
Phi X 174
Reduction
2
4
3
1
TDS
Reduction
2
4
3
1
The rankings are given left to right across the table in the order in which the challenges were
performed. The rankings are very consistent, except for H. pseudoflava reduction. A possible
explanation for this is that this organism was the first challenge, on days one and two before
membrane performance stabilized. Ranking unit performance separately for the two B. diminuta
challenge days (data not shown), shows that on day four the rankings are identical to those for
the viruses and TDS. This indicates that perhaps it takes approximately four days of operation,
or four tank fill cycles (including the manufacturer's recommended conditioning) for system
performance to stabilize.
22
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Chapter 5
QA/QC
5.1 QA/QC Responsibilities
NSF QA/QC staff reviewed the raw data records for compliance with QA/QC requirements and
checked 100% of the data against the reported results in the official lab reports.
5.2 Test Procedure QA/QC
The test procedure followed an NSF SOP created specifically for this ETV test.
5.3 Water Chemistry Analytical Methods QA/QC
• pH - Three point calibration at pH 4, 7, and 10 was conducted daily using traceable
buffers. The calibration is checked with a pH 8 buffer. During the challenge testing
periods, the precision of the instrument was checked by collecting a sample of drinking
water and splitting it into two samples for pH measurement. The relative percent
deviation (RPD) was calculated using the equation in Section 5.7.3. The acceptable RPD
limit was 10%. The daily pH 8 buffer readings and results of the duplicate analyses are
given in Table B-l of Appendix B.
• Temperature - The digital thermometer is calibrated every six months using a Hart
Scientific Model 9105 Dry Well Calibrator.
• Total Chlorine - The instrument was calibrated daily according to the manufacturer's
instructions. During the challenge testing periods, the precision of the instrument was
checked daily by analyzing a sample of municipal drinking water in duplicate. The
samples were diluted by approximately 50% with deionized water, and then split into
subsamples for analysis. The RPD for the two samples was then calculated, with an
acceptable RPD limit of 10%. Results of the duplicate analyses are given in Table B-3 of
Appendix B.
• Total Dissolved Solids - The Oakton 510 Series pFI/Conductivity meter was calibrated
daily using a potassium chloride QC standard. The calibration was checked with a
second potassium chloride QC standard. The Fisher Scientific Traceable™ Conductivity
Meter was calibrated with two potassium chloride standards. A third QC standard was
then used to check the calibration. Ten percent of samples were analyzed in duplicate,
and RPDs were calculated. The acceptable RPD limit was 10%. The calibration check
standard measurements and duplicate analyses are given in Table B-2 of Appendix B.
5.4 Microbiology Laboratory QA/QC
5.4.1 Growth Media
All media was checked for sterility and positive growth response when prepared and when used
for microorganism enumeration. The media was discarded if growth occurred on the sterility
check media, or if there is an absence of growth in the positive response check. All three E. coli
23
-------
hosts for the viruses were plated on ISA and incubated with the virus enumeration plates during
sample enumeration as a second positive growth control. B. diminuta and H. pseudoflava from
the stock cultures were plated on R2A agar and incubated with the bacteria enumeration plates as
positive controls.
5.4.2 Bacteria Cell Size
The theoretical minimum size for B. diminuta and H. pseudoflava cells is 0.2 to 0.3 jam in
diameter, however, the NSF Microbiology Laboratory was not able to achieve that size. The
stock culture was examined microscopically using a stage micrometer, and the observed
diameters were approximately 0.5 jam. To achieve the smallest cell size, the bacteria need to be
grown in a medium such as Saline Lactose Broth that keeps the cells small due to osmotic
pressure constraints. However, this medium is low in nutrients, so the Microbiology Laboratory
had difficulty cultivating the bacteria in high liters. The Microbiology Laboratory instead
cultivated the bacteria in TSB. TSB is more nutrient rich, and as a result yielded larger cells.
The larger cell size may have enhanced the bacteria reduction performance of the test units, so
the bacteria reduction data cannot be used to predict expected performance against bacterial
agents smaller than 0.5 jam. However, the viruses used in this study are much smaller than any
bacteria, so the virus challenges could be considered to be a more conservative challenge than
the smallest size bacteria.
5.4.3 Sample Processing and Enumeration
All samples were enumerated in triplicate. For each sample batch processed, an unused
membrane filter, and a blank with 100 ml of PBDW filtered through the membrane were also
placed onto the appropriate media and incubated with the samples as negative controls. No
growth was observed on any blanks.
5.4.4 Heterotrophic Bacteria Interference
As discussed in Section 3.2.4.5, heterotrophic bacteria also grew with the challenge organisms
on the agar plates for the effluent samples, because the challenge organisms had to be grown on
nonselective media. In many instances, the heterotrophic bacteria were present at levels that
gave up to 250 colonies on the 10"4 dilution plates, and almost confluent lawns on the 10"2
dilution and undiluted sample plates. However, the microbiologists were able to observe and
count the challenge organism colonies on these plates, due to their color and morphology. The
H. pseudoflava and B. diminuta colonies were circular, entire, and convex, whereas the
heterotrophic bacteria colonies were circular, but with slightly undulate edges, and they were flat
or raised, instead of convex. The H. pseudoflava and B. diminuta colonies were also smaller
than most of the heterotrophic colonies. The H. pseudoflava were bright yellow, and the B.
diminuta colonies were an off-white, slightly grayish color. Most of the heterotrophic bacteria
colonies were tan colored.
24
-------
5.5 Sample Handling
All samples analyzed by the NSF Microbiology and Wet Chemistry Laboratories were labeled
with unique ID numbers. These ID numbers appeared on the NSF lab report for the tests. All
water chemistry samples were analyzed within allowable hold times. All samples for bacteria
and virus analysis were processed within one hour of collection.
5.6 Documentation
All laboratory activities were documented using lab bench sheets and NSF laboratory reports.
This documentation can be found in the appendices.
5.7 Data Quality Indicators
The quality of the data generated for this ETV test can be established through five indicators of
data quality: representativeness, accuracy, precision, statistical uncertainty, and completeness.
5.7.1 Representativeness
Representativeness refers to the degree to which the data accurately and precisely represent the
expected performance of the RO system under normal use conditions. Representativeness of the
test units themselves was ensured by using the equipment selection criteria as described in
Section 3.2.1.
The test protocol was designed to be a conservative evaluation of product performance. The test
water was of very low turbidity to minimize the potential of microbial adhesion to suspended
particles, which could enhance apparent log reduction. The surrogates were chosen because of
their small size. The virus surrogate challenges were conducted at different pH values in an
attempt to assess whether pH affects the performance of the RO membrane. RO membrane
performance was also evaluated at both 40 and 80 psig inlet pressure.
5.7.2 Accuracy
Accuracy of the pH and total chlorine measurement instruments was evaluated with calibration
check standards during the daily calibrations. Accuracy of the conductivity meter used for TDS
analyses was measured through the use of QC samples. Accuracy measurements for these
parameters are given in Appendix B.
5.7.3 Precision
Precision refers to the degree of mutual agreement among individual measurements and provides
an estimate of random error. The bacteria and viruses were enumerated in triplicate, although no
precision calculations were made. One sample per batch was analyzed in duplicate for the TDS
measurements. Duplicate municipal drinking water samples were analyzed for pH and total
chlorine as part of the daily calibration process. Precision of the water chemistry duplicate
analyses was measured by use of the following equation to calculate RPD:
25
-------
where:
Sl = sample analysis result; and
S2 = sample duplicate analysis result.
The RPD calculations for individual duplicate pairs are given in the tables in Appendix B. The
duplicate measurements for the two TDS sample batches gave RPD values of 0% and 8.7%. The
RPD values for the pH measurements ranged from 0% to 0.9%, with a mean of 0.3%. The RPD
values for the total chlorine measurements ranged from 0% to 6.3%, with a mean of 1.3%.
5.7.4 Statistical Uncertainty
Statistical uncertainty can be expressed using confidence intervals. No data for this ETV test
was suitable for confidence interval calculations.
5.7.5 Completeness
Completeness is the proportion of valid, acceptable data generated using each method as
compared to the requirements of the test/QA plan. The completeness objective for data
generated during verification testing is based on the number of samples collected and analyzed
for each parameter and/or method.
Table 5-1. Completeness Requirements
Number of Samples per Percent
Parameter and/or Method Completeness
(MO 80%
11-50 90%
> 50 95%
Completeness is defined as follows for all measurements:
%C = (V/T)X100
where:
%C = percent completeness;
V = number of measurements judged valid; and
T = total number of measurements.
26
-------
5.7.5.1 Completeness Measurements
5.7.5.1.1. Number of Units Tested
The test/QA plan called for testing ten units. However, one of the units in the unconditioned
group did not function properly, as discussed in Section 3.2.4.5, so only nine units were tested.
This gives a completeness measure of 90%.
5.7.5.1.2. pH, Temperature, and Total Chlorine
As discussed in Section 4.2.3, the test/QA plan called for measuring pH and the other water
chemistry parameters at the beginning and end of the daily challenge periods. However, pH,
temperature, and total chlorine were only measured at the beginning of the challenge period.
Sixty-five samples should have been measured for these parameters, but only 45 were, giving a
completeness of 69%.
Of the missed analyses, the loss of the pH data was the most crucial. The loss of this data
precluded analysis of the pH drift issue or the effect of pH on test unit performance, as discussed
in Section 4.2.3. However, the lack of this data does not diminish the quality of the bacteria and
virus data itself. The temperature likely did not rise or drop out of the allowable range if it
wasn't already at the beginning of the challenge periods, since the water was kept at room
temperature. The missed total chlorine measurements also are not crucial, since the amount of
chlorine in the test water could not increase above the initial level.
5.7.5.1.3. Microbiological Analyses
One hundred and forty influent and effluent samples were to be collected for microbiological
analysis. However, since only nine units were tested, only 120 samples were collected, for a
completeness of 86%. Likewise, the 140 samples were to yield 924 plate counts for bacteria and
virus enumeration, but the 120 samples collected instead gave 858 plate counts. There was one
plate that gave an invalid result because of a lab accident, so the plate count completeness
measure is 857 out of 924, which gives 93%.
5.7.5.1.4. TDS
Fourteen samples were to be collected for the two TDS challenge system check tests described in
3.2.4.2. However, since only nine units were tested, only thirteen samples were collected. This
gives a completeness measure of 93%.
5.8 Measurements Outside of the Test/QA Plan Specifications
5.8.1 Total Chlorine
The test/QA plan called for the test water to have a total chlorine level below 0.05 mg/L. Of the
45 total chlorine measurements collected during testing, two were above the allowable level.
One was 0.05 mg/L, and the other was 0.07 mg/L. Both of these measurements could be due to
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the instrument's random error, and they both occurred during the 25-day conditioning period, so
they are not significant deviations.
5.8.2 Temperature
The test/QA plan called for the water temperature to be 20 ± 2.5°C. On day 15 of the
conditioning period, the water temperature was measured at 26°C. This is not a significant
deviation. Temperature control was critical during the bacteria challenge periods because of its
effect on organism viability. However, during the conditioning period, the water temperature
only affected the treated water production rate of the test units.
5.8.3 pH
The test water pH for the conditioned units pH 9.0 ± 0.5, 80 psig challenge was only 7.9. As
discussed in Section 4.2.3, the laboratory technicians had difficulty maintaining the pH within
the allowable range due to the low buffering capacity of the test water. This is a significant
deviation from the test/QA plan, but not one that invalidates the virus reduction data. It does,
however, invalidate comparison of the data based on pH.
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Chapter 6
References
American Society of Testing Materials (2001). D 3862-80, Standard Test Method for Retention
Characteristics of 0.2-|j,m Membrane Filters Used in Routine Filtration Procedures for the
Evaluation of Microbiological Water Quality, in Annual Book of'ASTMStandards, Volume
11.01. West Conshohocken, PA. ASTM.
APHA, AWWA and WPCF (1998). Standard Methods for Examination of Water and
Wastewater. 20th ed. Washington, D.C. APHA.
NSF International (2002). NSF/ANSI55-2002, Ultraviolet Microbiological WaterTreatment
Systems. Ann Arbor, NSF International.
NSF International (2002). NSF/ANSI 58 - 2002, Reverse Osmosis Drinking Water Treatment
Systems. Ann Arbor, NSF International.
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Chapter 7
Vendor Comments
Watts Premier submitted the following comments on the DRAFT report to the NSF. These
comments were not included in the body of the text.
7.1 Section 2.3 Trade Names - Addition
Watts Premier has recently launched a new line of point of use reverse osmosis units. Watts
Premier considers the results in this ETV report to also be valid for this new line of products.
The new products use the same filtration components as the Ultra 5, and function at the same
flux, therefore providing the same level of performance. An independent evaluation of the new
products was conducted by NSF's certification program staff. NSF determined that the test
results for the NSF certification of the Ultra 5 under NSF/ANSI Standard 58 can also apply to
the NSF certification of the new devices. Based upon this, the results obtained within this ETV
report are valid for the following additional models:
• WP-5
• KP-5
• RO-5M
• RO5M-50
Watts Premier has also recently launched a line of water purification reverse osmosis units. This
device incorporates a patented microbiological interception filter in addition to the RO
membrane. The test results contained with in this report do not reflect the reduction capabilities
of the purifier reverse osmosis as all filters other than the RO membrane were removed for the
testing in this report.
7.2 HPC Interference
When sampling from auxiliary outlets as observed with in this testing, the EPA recommends
sanitization of the outlet with sodium hypochlorite in order to remove possible HPC sample
contamination originating from the outlet faucet. This sanitization procedure was not conducted
during this testing. Incidental contact with water outlets can significantly alter HPC counts with
in any testing. Additionally, as concluded by the NSF International / World Health Organization
Symposium on HPC Bacteria in Drinking Water, HPC by themselves, do not indicate increased
risks to consumers unless they happen to correspond with sanitary contamination, which is
detectable by other more specific methods.
7.3 Conclusion
The goal of the ETV program is to further environmental protection by accelerating the
acceptance and use of improved and cost-effective technologies. As part of the national
Homeland Security effort, NSF through its ETV program has developed a test/QA plan under the
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EPA ETV program for evaluating POU drinking water treatment systems for removal of
biological contamination agents. This test/QA plan uses surrogate bacteria and viruses in place of
testing with the actual agents of concern.
The verifications serve to inform the public of the possible avenues they can pursue in order to
provide personal protection against biological contamination agents afforded to them by the use
of verified systems. This is accomplished by evaluating the reduction in risk of potential
exposure to biological agents in drinking water treated by the tested system in comparison to
drinking water directly from the public water supply system.
The Watts Premier Ultra 5 and affiliated reverse osmosis systems demonstrated through this
ETV testing removal of 97.4% to 99.9999996% bacteria and 99.5% to 99.9999% viruses from
the drinking water. Higher levels of reduction were obtained when the reverse osmosis systems
were installed and running for 25 days prior to challenging the unit with water contaminants.
Based upon these results, the use of these devices would significantly reduce the risk of exposure
to water borne bacteria and virus in the event there is a contamination incident within the
municipal or private water distribution system.
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