September 2009
NSF 09/30/EPADWCTR
EPA/600/R-09/109
Environmental Technology
Verification Report
Removal of Microbial Contaminants in
Drinking Water
Siemens Corporation
Memcorฎ L10V Ultrafiltration Module
Prepared by
NSF International
Under a Cooperative Agreement with
U.S. Environmental Protection Agency
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THE ENVIRONMENTAL TECHNOLOGY VERIFICATION
PROGRAM
oEPA
ET
V^lVl
V
U.S. Environmental Protection Agency
NSF International
ETV Joint Verification Statement
TECHNOLOGY TYPE: ULTRAFILTRATION
APPLICATION: REMOVAL OF MICROBIAL CONTAMINANTS
PRODUCT NAME: MEMCORฎ L10V ULTRAFILTRATION MODULE
VENDOR: SIEMENS WATER TECHNOLOGIES CORPORATION
ADDRESS: 181 THORN HILL ROAD
WARRENDALE, PA 15086
PHONE: 724-772-0044
EMAIL: INFORMATION.WATER@SIEMENS.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 Siemens Memcorฎ L10V ultrafiltration (UF)
module for removal of microbial contaminants under controlled laboratory challenge conditions. The
challenge tests were conducted at NSF's testing laboratory in Ann Arbor, MI. Testing of the Siemens
Memcorฎ L10V UF membrane module was conducted to verify microbial reduction performance under
the membrane challenge requirements of the USEPA Long Term 2 Enhanced Surface Water Treatment
Rule (LT2ESWTR).
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 09/30/EPADWCTR The accompanying notice is an integral part of this verification statement. August 2009
VS-i
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ABSTRACT
The Siemens Memcor L10V UF module was tested for removal of Cryptosporidium parvum oocysts,
endospores of the bacteria Bacillus atrophaeus, and the MS2 coliphage virus according to the
requirements of the EPA Long-Term 2 Enhanced Surface Water Treatment Rule (LT2ESWTR). Five
modules from five different production lots were challenged by all three organisms. Separate challenges
were conducted for each organism. The modules were operated at a target flux of 80 gallons per square
foot per day (gfd), which for the L10V equates to approximately 14 gallons per minute (gpm).
The LT2ESWTR specifies that log removal values (LRV) be calculated for each module for each
organism, and then one LRV for each organism (LRVc-TEsi) be assigned from the set of LRV. However,
the rule does not specify how the LRVC_TEST should be determined, instead, three different methods are
suggested. All three methods were used to assign LRV for this verification. See the Verification of
Performance section below for descriptions of each method. The LRVC.TEST for each method are
presented in Table VS-i.
Table VS-i. LRVC-TEsx for Each Organism
Challenge
Organism
C. parvum
B. atrophaeus
MS2
Method 1
5.67
6.56
2.07
Method 2
5.67
6.64
2.08
Method 3
5.51
5.99
1.94
PRODUCT DESCRIPTION
The Memcor L10V UF membrane module is a member of the Memcor XP line of products. The module
measures 4.7 inches in diameter by 45.5 inches in length. The membrane fibers are made of
polyvinylidene fluoride (PVDF). Water flow through the membrane fibers is outside to inside. The
modules operate in a dead-end mode, with no reject stream. The nominal pore size is 0.04 (im.
Siemens supplied five modules from five different production runs for testing. The modules were tested
in a pilot unit supplied by Siemens.
VERIFICATION TEST DESCRIPTION
Challenge Organisms
The L10V modules were tested for removal of microorganisms using live C. parvum oocysts, endospores
of the bacteria 5. atrophaeus (ATCC 9372, deposited as Bacillus subtilis var. niger), and MS-2 coliphage
virus (ATCC 15597-B1). B. atrophaeus was selected for evaluation as a possible surrogate for C. parvum,
due to the high cost and lack of availability of suitable numbers of C. parvum for challenge testing. Virus
reduction was evaluated using MS-2 for possible virus removal credits. MS-2 is considered a suitable
surrogate for pathogenic viruses because of its small size, at 24 nm in diameter. Separate challenge tests
were conducted for each challenge organism, so each module was tested three times over the course of the
testing activities.
Test Site and Challenge Water
The microbial challenge tests were conducted at NSF's testing laboratory in Ann Arbor, MI. Local tap
water was treated by carbon filtration, reverse osmosis, ultraviolet disinfection, and deionization to make
the base water for the tests. A water supply tank was filled with the base water, and sodium bicarbonate
was added in sufficient quantity to provide alkalinity at a target of 100 ฑ 10 mg/L as calcium carbonate.
The pH was then lowered with hydrochloric acid to a target range of 7.5 ฑ 0.5.
NSF 09/30/EPADWCTR
The accompanying notice is an integral part of this verification statement. September 2009
VS-ii
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Methods and Procedures
The tests followed the procedures described in the Test/QA Plan for the Microbial Seeding Challenge
Study of the Siemens Memcor L10V, L20V, and S10V Ultrafiltration Modules. The challenge protocol
was adapted from the ETV Protocol for Equipment Verification Testing for Physical Removal of
Microbiological and Paniculate Contaminants, and the USEPA Membrane Filtration Guidance Manual
(MFGM).
The pilot unit holds three modules, but each module was tested separately. Each module was tested in the
same housing. The other two housings were closed off. The target flux for the tests was 80 gallons per
square foot per day (gfd), which equals a flow rate of 14 gallons per minute (gpm) for the L10V module.
Before and after each challenge test, the modules were subjected to a two minute pressure decay test
using the program in the pilot unit's programmable logic controller (PLC). Siemens defined a passing
pressure decay test as less than or equal to 1.5 psi per minute. The PLC gives a warning message if this
decay rate is exceeded.
Prior to the start of each challenge test, the module and pilot unit were flushed for approximately two
minutes, and at the end of the flush a negative control sample was collected from the filtrate sample tap.
The duration of each microbial challenge test was 30 minutes. Feed and filtrate grab samples were
collected for challenge organism enumeration after three minutes of operation, after 15 minutes of
operation, and after 30 minutes of operation. The challenge organisms were intermittently injected into
the feed stream using a peristaltic pump at each sampling point. The injection point was downstream of
the pilot unit's feed tank, as shown in Figure 2.2. The injection time for MS-2 and B. atrophaeus was
approximately 5 minutes. During each injection period, the challenge organism was fed to the feed
stream for at least 3 minutes prior to collection of the feed and filtrate samples during the fourth and/or
fifth minutes. The injection time for C. parvum was only three minutes, due to the cost and limited
availability of live oocysts. The feed and filtrate samples for the C. parvum challenges were collected
during the third minute of injection.
The MFGM suggests that feed and filtrate samples not be collected until at least three hold-up volumes of
water containing the challenge organism have passed through the membrane to establish equilibrium.
The hold-up volume is defined as the "unfiltered test solution volume that would remain in the system on
the feed side of the membrane at the end of the test." Siemens has calculated that the hold-up volume for
the Memcor XP pilot unit with only one membrane cartridge in place is 7 gallons, not including the unit's
feed tank. These challenges were conducted at flow rates of approximately 14 gpm, so for both
organisms the equilibrium requirement was met prior to sample collection. For the B. atrophaeus
challenges, 42 gallons of the spiked test water passed through the membranes prior to sample collection.
For the C. parvum challenges, 28 gallons of spiked test water passed through the membranes prior to
sample collection.
VERIFICATION OF PERFORMANCE
The MS-2 challenges were conducted first on all five cartridges, followed by B. atrophaeus and then C.
parvum. However, the MS-2 challenges for Modules 2 and 3 were re-run in between the B. atrophaeus
and C. parvum challenges. The Module 2 challenge was run again because the MS-2 feed counts at 15
minutes were low. The Module 3 challenge was re-run because the pre-test flush sample had high MS-2
counts. Note that no MS-2 was detected in the retest flush sample.
The LT2ESWTR and MFGM specify that a LRV for the test (LRVc-TEsi) be calculated for each module
tested, and that the LRV for each module are then combined to yield a single LRVC.TEST for the product.
If fewer than 20 modules are tested, as was the case for this verification, the LRVC.TEST is simply the
NSF 09/30/EPADWCTR The accompanying notice is an integral part of this verification statement. September 2009
VS-iii
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lowest LRV for the individual modules. However, the rule does not specify a method to calculate LRVC.
TEST for each module. Suggested options in the MFGM include the following: calculating a LRV for each
feed/filtrate sample pair, then calculating the average of the LRV (Method 1); averaging all of the feed
and filtrate counts, and then calculating a single LRV for the module (Method 2); or calculating a LRV
for each feed/filtrate sample pair, and then selecting the LRV for the module as the lowest (most
conservative of the three options, Method 3).
All three approaches for calculating the LRV are reported here. Note the LT2ESWTR and MFGM do not
specify whether the averages should be calculated as the arithmetic mean or geometric mean. For this
verification, geometric means were calculated.
All pressure decay rates were below 0.06 psig/min, indicating that there were no membrane integrity
issues during the tests.
C. parvum Reduction
The C. parvum feed concentrations ranged from 3.2xl05 to 7.5xl05 oocysts/L. The C. parvum LRV from
the three different calculation methods are presented in Table VS-i. The LRVC_TEST for each method is in
bold font. All filtrate samples were negative for C. parvum, so the LRVs are simply a function of the
measured feed concentrations. The flow rates measured during the C. parvum challenges translated into
fluxes ranging from 79.4 to 81.9 gfd.
Table VS-i. C. parvum LRV Calculations
Module #
Module 1
Module 2
Module 3
Module 4
Module 5
Method 1
5.81
5.68
5.68
5.67
5.70
Method 2
5.81
5.68
5.69
5.67
5.70
Method 3
5.76
5.51
5.61
5.67
5.67
B. atrophaeus Reduction
The LT2ESWTR indicates a maximum challenge concentration to achieve a reduction of 6.5 logio
(3.16xl06 CPU/100 mL). The B. atrophaeus feed concentrations for these tests ranged from 6.0xl06 to
l.lxlO7 CFU/100 mL, taking into account the expected percent recovery of the challenge organism,
which is typically less than 100%.
The B. atrophaeus LRV from the three different calculation methods are presented in Table VS-ii. The
LRVc-TEsi for each method is in bold font. The LT2ESWTR specifies that the maximum possible LRVC.
TEST awarded to a membrane product is 6.5 logio, but the LRV above 6.5 are still presented here. The
for Methods 1 and 2 are above 6.5, while that for Method 3 falls below 6.5, at 5.99.
Table VS-ii. B. atrophaeus LRV Calculations
Module #
Module 1
Module 2
Module 3
Module 4
Module 5
Method 1
6.67
6.69
6.99
6.56(1)
6.86
Method 2
6.67
6.85
6.99
6.64(1)
6.86
Method 3
6.35
6.38
6.98
5.99
6.80
(1) LRVc-TEsi under these two methods should be capped at 6.5.
NSF 09/30/EPADWCTR
The accompanying notice is an integral part of this verification statement. September 2009
VS-iv
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No B. atrophaeus endospores were found in any of the filtrate samples for the Modules 3 and 5, but B.
atrophaeus was found in some of the filtrate samples for the other modules. The maximum observed
filtrate count for all modules was 6 CFU/100 mL. The flow rates measured during the B. atrophaeus
challenges translated into fluxes ranging from 80.2 to 84.0 gfd.
While the LRV for the B. atrophaeus challenges are higher than those for the C. parvum challenges, this
observation is a function of the high feed concentrations of the organisms. B. atrophaeus can be
considered to be a conservative surrogate for C. parvum because the endospores were found in the filtrate
samples for three of the five modules tested, while no C. parvum was found in any filtrate samples. Other
rationale for B. atrophaeus as a surrogate for C. parvum can be found in the full verification report.
MS-2 Reduction
The MS-2 feed concentrations ranged from 9.7xl03 PFU/mL to 7.8xl04 PFU/mL. The LRV for MS-2
reduction are shown in Table VS-iii. The LRVc-iEsi for each method is in bold font. The maximum
individual filtrate count was 187 PFU/mL for Module 2 at start-up. The flow rates measured during the
MS-2 challenges translated into fluxes ranging from 80.6 to 83.7 gfd.
Table VS-iii. MS-2 LRV Calculations
Module #
Module 1
Module 2
Module 3
Module 4
Module 5
Method 1
2.88
2.07
2.65
2.57
2.32
Method 2
2.88
2.08
2.66
2.58
2.33
Method 3
2.83
1.94
2.42
2.26
2.09
QUALITY ASSURANCE/QUALITY CONTROL (QA/QC)
NSF provided technical and quality assurance oversight of the verification testing as described in the
verification report, including a review of 100% of the data. NSF QA personnel also conducted a technical
systems audit during testing to ensure the testing was in compliance with the test plan. A complete
description of the QA/QC procedures is provided in the verification report.
Original signed by Sally Gutierrez 09/30/09
Sally Gutierrez Date
Director
National Risk Management Research
Laboratory
Office of Research and Development
United States Environmental Protection
Agency
Original signed by Robert Ferguson 11/05/09
Robert Ferguson Date
Vice President
Water Systems
NSF International
NSF 09/30/EPADWCTR
The accompanying notice is an integral part of this verification statement. September 2009
VS-v
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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 09/30/EPADWCTR) are available from the following sources:
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/info/etv
EPA web site: http://www.epa.gov/etv
NSF 09/30/EPADWCTR The accompanying notice is an integral part of this verification statement. September 2009
VS-vi
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September 2009
Environmental Technology Verification Report
Removal of Microbial Contaminants in Drinking Water
Siemens Corporation
Memcorฎ L10V Ultrafiltration Module
Prepared by:
Mike Blumenstein, Senior Project Manager
Bruce Bartley, Technical Manager
NSF International
Ann Arbor, Michigan 48105
and
Jeffrey Q. Adams, Project Officer
National Risk Management Research Laboratory
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
Under a cooperative agreement with the U.S. Environmental Protection Agency
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Notice
The U.S. Environmental Protection Agency, through its Office of Research and Development,
funded and managed, or partially funded and collaborated in, the research described herein. It
has been subjected to the Agency's peer and administrative review and has been approved for
publication. Any opinions expressed in this report are those of the author(s) and do not
necessarily reflect the views of the Agency, therefore, no official endorsement should be inferred.
Any mention of trade names or commercial products does not constitute endorsement or
recommendation for use.
11
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Foreword
The EPA is charged by Congress with protecting the nation's air, water, and land 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, the EPA's Office of Research and
Development provides data and science support that can be used to solve environmental
problems and to build the scientific knowledge base needed to manage our ecological resources
wisely, to understand how pollutants affect our health, and to prevent or reduce environmental
risks.
The Environmental Technology Verification (ETV) Program has been established by the EPA to
verify the performance characteristics of innovative environmental technology across all media
and to report this objective information to permitters, buyers, and users of the technology, thus
substantially accelerating the entrance of new environmental technologies into the marketplace.
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 six 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 has received EPA funding to plan, coordinate,
and conduct technology verification studies for the ETV "Drinking Water Systems Center" and
report the results to the community at large. The DWS Center has targeted drinking water
concerns such as arsenic reduction, microbiological contaminants, particulate removal,
disinfection by-products, radionuclides, and numerous chemical contaminants. Information
concerning specific environmental technology areas can be found on the internet at
http://www.epa.gov/nrmrl/std/etv/verifications.html.
in
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Acknowledgments
The authors wish to acknowledge the support of all those who helped plan and conduct the
verification test, analyze the data, and prepare this report. We sincerely appreciate the
involvement and support of all staff from the NSF testing laboratory who were involved with
testing activities for this verification. In particular, we would like to thank Mr. Sal Aridi, P.E.,
laboratory manager, and Mr. Kevin Schaefer, the testing engineer for this project. The NSF
Microbiology Laboratory analyzed all of the feed and filtrate samples for the tests. From this
laboratory, the authors would like to thank Robert Donofrio, PhD, Director of the NSF
Microbiology Laboratory, Robin Bechanko, Senior Microbiologist, and Kathy O'Malley,
Microbiologist. From the NSF QA Department, the authors wish to thank Joe Terrell,
Supervisor of QA and Safety, for auditing the tests and also reviewing all of the test data.
Finally, we would like to thank Richard Sakaji, PhD of the East Bay Municipal Utility District,
Patrick Cook of the Michigan Department of Environmental Quality, and Jonathan Pressman of
the U.S. EPA, for their reviews of this verification report.
IV
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Table of Contents
Verification Statement VS-i
Title Page i
Notice ii
Foreword iii
Acknowledgements iv
Table of Contents v
List of Tables vi
List of Figures vii
Abbreviations and Acronyms viii
Chapter 1 Introduction 1
1.1 ETV Program Purpose and Operation 1
1.2 Purpose of Verification 1
1.3 Testing Participants and Responsibilities 2
1.3.1 NSF International 2
1.3.2 U.S. Environmental Protection Agency 2
1.3.3 Siemens Corporation 2
Chapter 2 Product Description 3
2.1 UF Membrane General Description 3
2.2 Memcor LI0V Membrane Module Description 3
2.3 Pilot Unit Used for Testing 4
Chapter 3 Methods and Procedures 6
3.1 Introduction 6
3.2 Challenge Organisms 6
3.3 UF Module Integrity Tests 7
3.4 Test Water Composition 7
3.5 Challenge Test Procedure 7
3.6 Analytical Methods 8
Chapter 4 Results and Discussion 10
4.1 Pressure Decay Test Results 10
4.2 C. parvum Challenge Tests 11
4.2.1 Choosing LRVc-xEsx from the Averages of the Individual LRV Calculations 12
4.2.2 LRVc-TEsx Calculated from the Mean Feed and Filtrate Counts 12
4.2.3 Choosing LRVc-xEsx from the Individual Sample Point LRV Calculations 12
4.3 B. atrophaeus Challenge Tests 13
4.3.1 Choosing LRVc-xEsx from the Averages of the Individual LRV Calculations 14
4.3.2 LRVc-xEsx Calculated from the Mean Feed and Filtrate Counts 14
4.3.3 Choosing LRVc-xEsx from the Individual Sample Point LRV Calculations 14
4.3.4 B. atrophaeus as a Surrogate for C. parvum 15
4.4 MS-2 Challenge Tests 15
4.4.1 Choosing LRVc-xEsx from the Averages of the Individual LRV Calculations 16
4.4.2 LRVc-xEsx Calculated from the Mean Feed and Filtrate Counts 16
4.4.3 Choosing LRVc-xEsx from the Individual Sample Point LRV Calculations 16
4.5 Operational Data and Water Quality Data for All Challenges 17
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Chapter 5 Quality Assurance/Quality Control 19
5.1 Introduction 19
5.2 Test Procedure QA/QC 19
5.3 Sample Handling 19
5.4 Chemistry Laboratory QA/QC 19
5.5 Microbiology Laboratory QA/QC 19
5.5.1 Growth Media Positive Controls 19
5.5.2 Negative Controls 19
5.6 Documentation 20
5.7 Data Review 20
5.8 Data Quality Indicators 20
5.8.1 Representativeness 20
5.8.2 Accuracy 20
5.8.3 Precision 21
5.8.4 Completeness 21
Chapter 6 References 23
Appendices
Appendix A Test/Quality Assurance Project Plan
Appendix B Bacillus Endospores as a Surrogate for C. parvum Oocysts
Appendix C Triplicate Challenge Organism Counts
List of Tables
Table 2-1. L10V Specifications 3
Table 2-2. Serial Numbers of Tested Modules 4
Table 3-1. Analytical Methods for Laboratory Analyses 9
Table 4-1. Pressure Decay Data 11
Table 4-2. C. parvum Challenge Results 11
Table 4-3. C. parvum LRVc-xEsx Calculated from the Mean Feed and Filtrate Counts 12
Table 4-4. C. parvum LRVC-xEsx from Individual LRVs 12
Table 4-5. B. atrophaeus Challenge Results 13
Table 4-6. B. atrophaeus LRVc-xEsx Calculated from the Mean Feed and Filtrate Counts 14
Table 4-7. B. atrophaeus LRVc-xEsx from Individual LRVs 14
Table 4-8. MS-2 Challenge Results 15
Table 4-9. MS-2 LRVC-xEsx Calculated from the Mean Feed and Filtrate Counts 16
Table 4-10. MS-2 LRVC-xEsx from Individual LRVs 16
Table 4-11. Operation Data 17
Table 4-12. Water Chemistry Data 18
Table 5-1. Completeness Requirements 21
VI
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List of Figures
Figure 2-1. Siemens Memcor XP pilot unit used for testing the UF modules 4
Figure 2-2. Challenge organism injection point and feed sample tap on pilot unit 5
vn
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Abbreviations and Acronyms
ATCC American Type Culture Collection
ฐC degrees Celsius
CPU colony forming units
cm centimeter
DWS Drinking Water Systems
EPM Electrophoretic Mobility
ETV Environmental Technology Verification
ฐF degrees Fahrenheit
ft foot(feet)
gfd gallons per square foot per day
gpm gallons per minute
in inch(es)
kPa kilopascals
L liter
LRV log removal value
LT2ESWTR Long Term 2 Enhanced Surface Water Treatment Rule
m meter
MFGM Membrane Filtration Guidance Manual
mg milligram
min minute
mL milliliter
mm millimeter
mM millimolar
MWCO molecular weight cutoff
NM not measured
NSF NSF International (formerly known as National Sanitation Foundation)
NTU Nephelometric Turbidity Unit
ORD Office of Research and Development
PFU plaque forming unit
PLC programmable logic controller
psig pounds per square inch, gauge
PVDF polyvinylidene fluoride
QA quality assurance
QC quality control
RPD relative percent difference
SM Standard Methods for the Examination of Water and Wastewater
TDS total dissolved solids
TOC total organic carbon
UF ultrafiltration
ug microgram
jam microns
uS microsiemens
USEPA U. S. Environmental Protection Agency
Vlll
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Chapter 1
Introduction
1.1 ETV Program Purpose and Operation
The U.S. Environmental Protection Agency (USEPA) 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;
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 USEPA has partnered with NSF International (NSF) under the ETV Drinking Water
Systems (DWS) Center to verify performance of drinking water treatment 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 USEPA. Rather, it recognizes
that the performance of the equipment has been determined and verified by these organizations
under conditions specified in ETV protocols and test plans.
1.2 Purpose of Verification
Testing of the Siemens Memcorฎ L10V ultrafiltration (UF) membrane module was conducted to
verify microbial reduction performance under the membrane challenge requirements of the
USEPA Long Term 2 Enhanced Surface Water Treatment Rule (LT2ESWTR). Please note that
this verification only addresses the challenge testing requirement of the LT2ESWTR, not direct
integrity testing or continuous indirect monitoring.
Please also note that this verification does not address long-term performance, or performance
over the life of the membrane. This verification test did not evaluate cleaning of the membranes,
nor any other maintenance and operation.
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1.3 Testing Participants and Responsibilities
The following is a brief description of each of the ETV participants and their roles and
responsibilities.
1.3.1 NSF International
NSF is an independent, not-for-profit organization dedicated to public health and safety, and to
protection of the environment. Founded in 1944 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 USEPA partnered with NSF to verify the performance of drinking
water treatment systems through the USEPA's ETV Program.
NSF performed all verification testing activities at its Ann Arbor, MI 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: NSF International
789 N. Dixboro Road
Ann Arbor, MI 48105
Phone: 734-769-8010
Fax: 734-769-0109
Contact: Mr. Bruce Bartley, Project Manager
Email: bartley@nsf.org
1.3.2 U.S. Environmental Protection Agency
USEPA, through its Office of Research and Development (ORD), has financially supported and
collaborated with NSF under Cooperative Agreement No. CR-833980-01. This verification
effort was supported by the DWS Center operating under the ETV Program. This document has
been peer-reviewed, reviewed by USEPA, and recommended for public release.
1.3.3 Siemens Corporation
Siemens Corporation supplied the tested membrane modules, and also a pilot testing unit in
which the membranes were tested. Siemens was also responsible for providing logistical and
technical support, as needed.
Contact: Siemens Water Technologies Corp.
725 Wooten Road
Colorado Springs, CO, 80915
Phone: +1 (719) 622-5326
Fax: +1 (719) 622-5399
Contact: Mr. Aaron Balczewski, Director of Process Technology, Memcor Products
Email: Aaron.Balczewski(3)siemens.com
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Chapter 2
Product Description
2.1 UF Membrane General Description
UF membranes remove contaminants from water through sieving based on the size of the
membrane pores relative to the physical size of the contaminant. A common arrangement for the
membranes is in hollow fibers, with the fibers "potted" in a resin. The flow of water through the
fibers can be either "inside-out" or "outside-in". UF membranes can be classified by pore size or
the molecular weight cutoff (MWCO) point. Pore sizes generally range from 0.01 to 0.05
microns (nm). Typical MWCO points are 10,000 to 500,000 Daltons, with 100,000 being a
common MWCO rating for drinking water treatment. With these specifications, UF membranes
can remove viruses, bacteria, and protozoan cysts, as well as large molecules such as proteins,
and suspended solids.
2.2 Memcor L10V Membrane Module Description
The Memcor LI 0V UF membrane module is a member of the Memcor XP line of products. The
module measures 4.7 inches in diameter by 45.5 inches in length. The membrane fibers are
made of polyvinylidene fluoride (PVDF). Water flow through the membrane fibers is outside to
inside. The modules operate in a dead-end mode, with no reject stream. The module
specifications are listed below in Table 2-1. The identification numbers and serial numbers for
the tested modules are listed in Table 2-2. Five modules from five different production lots were
submitted by Siemens for testing. The assigned module numbers in Table 2-2 correspond to the
module numbers in the Results and Discussion chapter.
Table 2-1. L10V Specifications
Parameter
Dimensions:
Cartridge outside diameter
Cartridge length
Nominal membrane pore size
Maximum membrane pore size
Average active membrane area (outer)
Operating Limits:
Operating temperature range
Maximum temperature
Max. transmembrane pressure
Operating pH range
Specification
4.7 inches (in) (119 millimeters (mm))
45.5 in (1157 mm)
0.04 urn
0.1 urn
252 square feet (ft2) (23.4 square meters (m2))
>32 - 104 Fahrenheit (ฐF) (>0 - 40 Celcius (ฐC))
113ฐF(45ฐC)
21.7 pounds per square inch, gauge (psig) (150 kilopascals )kPa))
2-10
-------
Table 2-2. Serial Numbers of Tested Modules
Module
1
2
3
4
5
Batch Number
33970
33602
33976
33900
33899
Identification Number
WM81B41Y
WL7BU33C
WM81G13L
WM7C552V
WM81324E
Serial Number
404932
397681
404817
403135
404385
2.3 Pilot Unit Used for Testing
Siemens supplied a pilot unit for testing along with the membrane cartridges. A diagram of the
pilot unit is shown below as Figure 2-1. The pilot unit holds three membrane cartridges, but only
one cartridge was tested at a time. The valves allowing water to pass through the other two
cartridge housings were closed off. The pilot unit programmable logic controller (PLC) includes
an automatic pressure decay test program. This program was used to evaluate the integrity of the
membranes before and after each microbial challenge test. The pilot unit automatic backflush
feature was disabled for the tests.
Figure 2-1. Siemens Memcor XP pilot unit used for testing the UF modules.
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The target flow rate was entered into the PLC, and the PLC then controlled the flow through the
pilot unit using internal pumps and pneumatic valves. However, the filtrate flow data presented
in the results and discussion chapter was collected from an NSF installed flow meter (Great
Plains Industries model A109GNA100NA10) on the filtrate line. The flow meter was calibrated
immediately prior to testing. The feed and filtrate pressure readings were taken from pressure
transducers already on the pilot unit. These pressure transducers were verified by an NSF
calibration officer prior to testing.
The feed water minus the challenge organism was pumped from NSF's feed tank into the pilot
unit's break tank using a pump belonging to NSF. From the break tank, the pilot unit feed pump
pulled water out of the break tank and sent it through the membrane module being tested. The
USEPA Membrane Filtration Guidance Manual (EPA 815-R-06-009) calls for the challenge
organism injection point to be more than ten pipe diameters upstream from the feed water sample
tap. Due to the compact design of the pilot unit, the challenge organism suspension was injected
using a peristaltic pump immediately upstream from the membrane feed pump, and the feed
sample tap was installed immediately downstream of the feed pump. The distance between the
two points was not measured, but it was assumed that the feed pump provided sufficient mixing
of the water. Figure 2-2 shows the injection point and the feed sample tap in relation to the feed
pump.
injection port
feed pump
sample tap
Figure 2-2. Challenge organism injection point and feed sample tap on pilot unit.
-------
Chapter 3
Methods and Procedures
3.1 Introduction
The challenge tests were conducted in May of 2008. The tests followed the procedures described
in the Test/QA Plan for the Microbial Seeding Challenge Study of the Siemens Memcor L10V,
L20V, and S10V Ultrafiltration Modules. The challenge protocol was adapted from the ETV
Protocol for Equipment Verification Testing for Physical Removal of Microbiological and
Particulate Contaminants, and the USEPA Membrane Filtration Guidance Manual (MFGM).
Note that the MFGM references the ETV protocol as an acceptable protocol for testing
membrane products according the to the USEPA requirements. The test/QA plan is included
with this report as Appendix A.
3.2 Challenge Organisms
The L10V modules were tested for removal of microorganisms using live Cryptosporidium
parvum oocysts, endospores of the bacteria Bacillus atrophaeus (American Type Culture
Collection, ATCC number 9372, deposited as Bacillus subtilis var. niger), and MS-2 coliphage
virus (ATCC 15597-B1). B. atrophaeus was selected for evaluation as a possible surrogate for C.
parvum, due to the high cost and lack of availability of suitable numbers of C. parvum for
challenge testing. The strain of B. atrophaeus used for testing yields orange colonies with a
distinctive morphology on trypicase soy agar (TSA), so it can be distinguished from wild-type
endospores that could be present as contamination. B. atrophaeus endospores are ellipsoidal
(football shaped), with an average diameter of 0.8 jam, and an average length of 1.8 jim. The
suitability of using B. atrophaeus as a surrogate for C. parvum for future verification tests was
evaluated by challenging the L10V modules with both organisms, and comparing the results.
See Appendix B for further discussion regarding the use of Bacillus endospores as a surrogate
for Cryptosporidium.
Virus removal testing was conducted using MS-2 for possible virus removal credits. MS-2 is
considered a suitable surrogate for pathogenic viruses because of its small size, at 24 nanometers
in diameter.
The challenge organism suspensions were injected into the feed water stream at a sufficient rate
to achieve the following target concentrations:
MS-2 - IxlO4 to IxlO5 plaque forming units per milliliter(PFU/mL);
B. atrophaeus - IxlO6 to 5xl06 colony forming units (CPU) per lOOmL; and
C. parvum - IxlO5 to IxlO6 oocysts per liter (L).
The MFGM calls for the maximum challenge concentration to be 6.5 logic above the organism's
detection limit (3.16x106). The goal for the B. atrophaeus challenges was to be able to measure
log reductions greater than six, so it was necessary to set the upper bound of the target range at
higher than 3.16xl06 CFU/100 mL to ensure that greater than IxlO6 CFU/100 mL were
measured in the feed samples.
-------
Note that the original target concentration for C. parvum was greater than IxlO6 oocysts/L.
However, using this target concentration was not possible due to the cost and the difficultly
acquiring the number of oocysts that would have been required.
The MS-2 stock suspension was purchased from Biological Consulting Services of North
Florida, Inc. B. atrophaeus was purchased from Presque Isle Cultures. The C. parvum oocysts
were purchased from Sterling Parasitology Lab.
3.3 UF Module Integrity Tests
Before and after each challenge test, each module was subjected to a two minute pressure decay
test using the program in the pilot unit's PLC. Siemens defined a passing pressure decay test as
less than or equal to 1.5 psig per minute (min). The PLC gives a warning message if this decay
rate is exceeded.
3.4 Test Water Composition
Local tap water was treated by carbon filtration, reverse osmosis, ultraviolet disinfection, and
deionization to make the base water for the tests. The base water has the following quality
control (QC) requirements for use in the NSF testing laboratory:
Conductivity <2 microsiemens (|o,S) per centimeter (cm) at 25ฐC;
Total organic carbon <100 micrograms (|o,g) per L;
Total chlorine <0.05 milligrams (mg) per L; and
Heterotrophic bacteria plate count <100 CFU/mL.
Of the above parameters, only total chlorine was measured specifically for this verification. The
other parameters are measured periodically by NSF as part of the internal quality assurance
(QA)/QC program for test water quality.
A 4,000-gallon water supply tank was filled with the base water, and sodium bicarbonate was
added in sufficient quantity to provide alkalinity at a target of 100 ฑ 10 mg/L as calcium
carbonate. The pH was then lowered with hydrochloric acid to a target range of 7.5 ฑ 0.5.
Feed samples were collected prior to each challenge period for analysis of total chlorine,
alkalinity, pH, temperature, total dissolved solids, and turbidity. These samples were collected
prior to addition of the challenge organism.
3.5 Challenge Test Procedure
The pilot unit holds three modules, but each module was tested separately, as discussed above in
Section 2.3. Each module was tested in the same cartridge housing. The other two housings
were closed off. The target flux for membrane operation was 80 gallons per square foot per day
(gfd) at 20 ฐC, which, for the L10V, equals a flow rate of 14 gallons per minute (gpm).
The modules were "brand new" when challenged. There was no seasoning period, or other
period of operation prior to the tests to allow any sort of a cake layer to build up. Testing new
modules represented a worse case field operation scenario.
-------
Separate challenge tests were conducted for each challenge organism, so each module was tested
three times over the course of the testing activities. Each module was installed in the membrane
chamber, and then the test engineer started operation of the pilot unit and allowed the PLC to run
through a start-up sequence of operations. Once normal filtration had started, the engineer
started a pressure decay test. After the pressure decay test was complete, the normal filtration
mode resumed. At this time, the engineer adjusted the flow rate to 14 gpm if necessary, and
collected a flush sample from the filtrate sample tap. At the end of each challenge test, a second
pressure decay test was conducted to confirm membrane integrity.
The duration of each microbial challenge test was 30 minutes. Feed and filtrate grab samples
were collected for challenge organism enumeration after three minutes of operation, after 15
minutes of operation, and after 30 minutes of operation. The challenge organisms were
intermittently injected into the feed stream using a peristaltic pump at each sampling point. The
injection point was downstream of the pilot unit's feed tank, as shown in Figure 2.2. The
injection time for MS-2 and B. atrophaeus was approximately 5 minutes. During each injection
period, the challenge organism was fed to the feed stream for at least 3 minutes prior to
collection of the feed and filtrate samples during the fourth and/or fifth minutes. The injection
time for C. parvum was only three minutes, due to the cost and limited availability of live
oocysts. The feed and filtrate samples for the C. parvum challenges were collected during the
third minute of injection.
The MFGM suggests that feed and filtrate samples not be collected until at least three hold-up
volumes of water containing the challenge organism have passed through the membrane, to
establish equilibrium (equilibrium volume). The hold-up volume is defined as the "unfiltered
test solution volume that would remain in the system on the feed side of the membrane at the end
of the test." Siemens has calculated that the hold-up volume for the Memcor XP pilot unit with
only one membrane cartridge in place is 7 gallons, not including the unit's feed tank. These
challenges were conducted at flow rates of approximately 14 gpm, so for both organisms the
equilibrium requirement was met prior to sample collection. For the B. atrophaeus challenges,
42 gallons of the spiked test water passed through the membranes prior to sample collection. For
the C. parvum challenges, 28 gallons of spiked test water passed through the membranes prior to
sample collection.
3.6 Analytical Methods
A list of laboratory analytical methods can be found in Table 3-1. All samples for challenge
organism enumeration were analyzed in triplicate.
The following are the analytical instruments used for water quality measurements:
Alkalinity - SmartChem Discrete Analyzer;
pH - Orion EA 940 pH/ISE meter;
Temperature - Fluke 51 II digital thermometer;
Total Chlorine - Hach DR/2010 spectrophotometer using AccuVac vials; and
Turbidity - Hach 21 OOP turbidimeter.
-------
Table 3-1. Analytical Methods for Laboratory Analyses
Parameter
Alkalinity (total, as CaCO3)
pH
Total Dissolved Solids (TDS)
Total Chlorine
Turbidity
MS-2
B. atrophaeus
Cryptosporidium Oocysts
Method
USEPA310.2
SM2 4500-H+
SM 2540 C
SM 4500-C1 G
SM2130
NSF 555
SM92186
USEPA 1623
NSF
Reporting
Limit
5mg/L
NA
5mg/L
0.05 mg/L
0.1 NTU4
1 PFU/mL
1 CFU/100 mL
1 oocyst/L
Lab
Accuracy
(% Recovery)
90-110
NA
90-110
90-110
95-105
Lab
Precision
(o/oRPD1)
<13
<10
<10
<10
Hold Time
14 days
none3
7 days
none3
none3
30 hours
30 hours
72 hours
(1) RPD = Relative Percent Deviation
(2) SM = Standard Methods
(3) Immediate analysis required
(4) NTU = Nephelometric Turbidity Unit
(5) Method published in NSF/ANSI Standard 55 - Ultraviolet Microbiological Water Treatment Systems. Method is similar to
EPA Method 1601.
(6) TSA was substituted for nutrient agar in SM 9218 so that the challenge endospores could be distinguished from wild-type
endospores. TSA gives orange colonies with a distinctive morphology.
-------
Chapter 4
Results and Discussion
The challenge tests were conducted from May 13, 2008 to May 28, 2008. The MS-2 challenges
were conducted first on all five cartridges, followed by B. atrophaeus and then C. parvum.
However, the MS-2 challenges for Modules 2 and 3 were re-run in between the B. atrophaeus
and C. parvum challenges. The Module 2 challenge was run again because the MS-2 feed counts
at 15 minutes were low. The Module 3 challenge was re-run because the pre-test flush sample
had high MS-2 counts. Note that no MS-2 was detected in the retest flush sample.
For presentation of the challenge organism data in this chapter, the observed triplicate counts
were averaged by calculating geometric means, as suggested for microbial enumeration data in
SM 9020. The mean counts were logio transformed for the purpose of calculating log removal
values (LRV). Samples with no organisms found were treated as 1 per unit volume for the
purpose of calculating the means, unless all triplicate analyses had no organisms found. The
triplicate counts for each sample are presented in Appendix C.
The LT2ESWTR and MFGM specify that an LRV for the test (LRVC-TEsx) be calculated for each
module tested, and that the LRVs for each module are then combined to yield a single LRVc-xEsx
for the product. If fewer than 20 modules are tested, as was the case for this verification, the
LRVc-xEsx is simply the lowest LRV for the individual modules. However, the rule does not
specify a method to calculate LRVC-xEsx for each module. Suggested options in the MFGM
include:
Calculate a LRV for each feed/filtrate sample pair, calculate the average of the LRV;
Average all of the feed and filtrate counts, and then calculate a single LRV for the
module; or
Calculate a LRV for each feed/filtrate sample pair, select the LRV for the module as the
lowest (most conservative of the three options).
In this section, all three approaches will be used to calculate the LRV for each module. Note the
LT2ESWTR and MFGM do not specify whether the averages should be calculated as the
arithmetic mean or geometric mean. Since the triplicate counts were averaged by calculating
geometric means, so too do the LRV calculations use geometric mean.
4.1 Pressure Decay Test Results
The pre-test and post-test pressure decay test results are presented in Table 4-1. All pressure
decay rates were below 0.06 psig/min, indicating that there were no membrane integrity issues
during the tests.
10
-------
Table 4-1. Pressure Decay Data
Module*
Module 1
Module 2
Module 3
Module 4
Module 5
MS-2 Pressure Decay
Data (psig/min)
Pre-Test
0.05
0.05
0.06
0.06
0.05
Post-Test
0.05
0.04
0.04
0.04
0.05
B. atrophaeus Pressure
Decay Data (psig/min)
Pre-Test
0.05
0.04
0.05
0.04
0.05
Post-Test
0.05
0.04
0.04
0.04
0.04
C. parvum Pressure
Decay Data (psig/min)
Pre-Test
0.06
0.04
0.05
0.05
0.05
Post-Test
0.05
0.03
0.06
0.04
NM1
(1) Not measured
4.2 C. parvum Challenge Tests
The C. parvum challenge data is presented in Table 4-2. All mean feed counts exceeded the
target concentration of IxlO5 oocysts/L. No C. parvum was found in any of the filtrate samples,
so the LRVc-TEsx for C. parvum is then simply a function of the feed concentrations.
Table 4-2. C. parvum Challenge Results
Module
Number
Module 1
Module 2
Module 3
Module 4
Module 5
Sample
Point
Flush
2 Minutes
15 Minutes
30 Minutes
Overall Mean
Flush
2 Minutes
15 Minutes
30 Minutes
Overall Mean
Flush
2 Minutes
15 Minutes
30 Minutes
Overall Mean
Flush
2 Minutes
15 Minutes
30 Minutes
Overall Mean
Flush
2 Minutes
15 Minutes
30 Minutes
Overall Mean
Feed
Geometric Mean
(Oocysts/L)
6.0xl05
7.5xl05
5.7xl05
6.4xl05
3.2xl05
5.8xl05
5.8xl05
4.8xl05
4.8xl05
5.8xl05
4.1xl05
4.9xl05
4.8xl05
4.7xl05
4.7xl05
4.7xl05
5.2xl05
4.7xl05
5.1xl05
5.0xl05
Log10
5.78
5.88
5.76
5.81
5.51
5.76
5.76
5.68
5.68
5.76
5.61
5.68
5.68
5.67
5.67
5.67
5.71
5.67
5.71
5.70
Filtrate
Geometric Mean
(Oocysts/L)
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
Log10
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
LRV
5.78
5.88
5.76
5.81
5.51
5.76
5.76
5.68
5.68
5.76
5.61
5.68
5.68
5.67
5.67
5.67
5.71
5.67
5.71
5.70
11
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4.2.1 Choosing LRVC-xEsx from the Averages of the Individual LRV Calculations
In Table 4-2, the LRV numbers in the "Overall Mean" rows are the geometric mean calculations
of the individual sample point LRV for each module. Using this approach, the lowest LRV, and
thus the LRVc-TEsx, is 5.67 for Module 4.
4.2.2 LRVc-TEsx Calculated from the Mean Feed and Filtrate Counts
Using this approach, log values need to be calculated for each overall mean feed and filtrate
count. In most cases these log values will be equal to the overall mean log values presented in
Table 4-2 as the mean of the individual logic values. However, in some instances, the log of the
overall mean feed or filtrate count will differ slightly from that calculated from the individual log
values. The log transformations of the overall mean feed and filtrate counts are presented in
Table 4-3. A comparison of the log values in Table 4-3 with the overall mean log values in
Table 4-2 shows that only one number is different. The log of the feed count for Module 3 is
5.69, whereas the geometric mean of the individual log values is 5.68. Under this approach the
LRVc-TEsx is still 5.67.
Table 4-3. C. parvum LRVc-xEsx Calculated from the Mean Feed and Filtrate Counts
Module Number
Module 1
Module 2
Module 3
Module 4
Module 5
Feed
Geometric Mean
(Oocysts/L)
6.4xl05
4.8xl05
4.9xl05
4.7xl05
5.0xl05
Log10
5.81
5.68
5.69
5.67
5.70
Filtrate
Geometric Mean
(Oocysts/L)
<1
<1
<1
<1
<1
Log10
0.0
0.0
0.0
0.0
0.0
LRV
5.81
5.68
5.69
5.67
5.70
4.2.3 Choosing LRVc-xEsx from the Individual Sample Point LRV Calculations
Looking back to Table 4-2, the LRV for the feed and filtrate pair at each sample point are given
in the last column of the table. The lowest individual LRV for each module are listed in Table 4-
4. Under this approach, the LRVc-xEsx is 5.51.
Table 4-4. C. parvum LRVc-xEsx from Individual LRVs
Module Number
Module 1
Module 2
Module 3
Module 4
Module 5
LRVc-TEST
5.76
5.51
5.61
5.67
5.67
12
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4.3 B. atrophaeus Challenge Tests
The B. atrophaeus challenge results are displayed in Table 4-5. All mean feed counts exceeded
the target concentration of IxlO6 CFU/100 mL. The LT2ESWTR indicates a maximum
challenge concentration to achieve a reduction of 6.5 logio (3.16xl06 CFU/100 mL), so that the
maximum LRVc-iEsx awarded to a membrane product is 6.5 logic. The B. atrophaeus feed
concentrations for these tests ranged from 6.0xl06 to l.lxlO7 CFU/100 mL. This takes into
account the expected percent recovery of the challenge organism, which is typically less than
100%.
No B. atrophaeus was found in any of the filtrate samples for the Module 3 and 5 tests, but
endospores were found in the filtrate samples at levels less than 1 logio for Modules 1, 2, and 4.
Note that 1 CFU/100 mL was found in the Module 1 and Module 4 flush samples. The modules
were not tested in order, Module 5 was challenged first on May 15, 2008, followed by Module 4
later that day, and Modules 1 through 3 on May 16. Since none of the Module 5 filtrate samples
had any detectible B. atrophaeus endospores, but the Module 4 flush sample and two of the
filtrate samples did, it is possible that pilot unit contamination is occurring during the module
changeouts.
Table 4-5. B. atrophaeus Challenge Results
Module 1
Module 2
Module 3
Module 4
Module 5
Sample
Point
Flush
3 Minutes
15 Minutes
30 Minutes
Overall Mean
Flush
3 Minutes
15 Minutes
30 Minutes
Overall Mean
Flush
3 Minutes
15 Minutes
30 Minutes
Overall Mean
Flush
3 Minutes
15 Minutes
30 Minutes
Overall Mean
Flush
3 Minutes
15 Minutes
30 Minutes
Overall Mean
Feed
Geometric Mean
(CFU/100 mL)
l.OxlO7
9.3xl06
9.0xl06
9.4xl06
6.0xl06
7.5xl06
S.lxlO6
7.1xl06
9.9xl06
l.OxlO7
9.6xl06
9.8xl06
l.OSxlO7
6.2xl06
9.7xl06
8.7xl06
6.3xl06
7.4xl06
S.OxlO6
7.2xl06
Logio
7.00
6.97
6.95
6.97
6.78
6.88
6.91
6.85
7.00
7.00
6.98
6.99
7.03
6.79
6.99
6.94
6.80
6.87
6.90
6.86
Filtrate
Geometric Mean
(CFU/100 mL)
1
2
1
4
2
<1
<1
3
<1
1
<1
<1
<1
<1
<1
1
<1
6
2
2
<1
<1
<1
<1
<1
Log10
0.3
0.0
0.6
0.3
0.0
0.5
0.0
0.2
0.0
0.0
0.0
0.0
0.0
0.8
0.3
0.4
0.0
0.0
0.0
0.0
LRV
6.70
6.97
6.35
6.67
6.78
6.38
6.91
6.69
7.00
7.00
6.98
6.99
7.03
5.99
6.69
6.56
6.80
6.87
6.90
6.86
13
-------
In spite of the filtrate endospore counts, most LRVs are above 6.5, no matter which of the
calculation methods is used. The LT2ESWTR specifies that the maximum possible LRVc-xEsx
awarded to a membrane product is 6.5 logic, but the LRVs above 6.5 are still presented here.
4.3.1 Choosing LRVC-xEsx from the Averages of the Individual LRV Calculations
In Table 4-5, the LRV numbers in the "Overall Mean" rows are the geometric mean calculations
of the individual sample point LRV for each module. Using this approach, the lowest LRV, and
thus the LRVc-TEsx, is 6.56 for Module 4.
4.3.2 LRVc-TEsx Calculated from the Mean Feed and Filtrate Counts
Using this approach, log values need to be calculated for each overall mean feed and filtrate
count. In most cases these log values will be equal to the overall mean log values presented in
Table 4-5 as the mean of the individual logic values. However, in some instances, the log of the
overall mean feed or filtrate count will differ slightly from that calculated from the individual log
values. The log transformations of the overall mean feed and filtrate counts are presented in
Table 4-6. Under this approach, the LRV for Modules 2 and 4 differ from the approach in
Section 4.3.1. Module 4 still gives the LRVC-xEsx, at 6.64.
Table 4-6. B. atrophaeus LRVc-xEsx Calculated from the Mean Feed and Filtrate Counts
Module Number
Module 1
Module 2
Module 3
Module 4
Module 5
Feed
Geometric Mean
(CFU/100 mL)
9.4xl06
7.1xl06
9.8xl06
8.7xl06
7.2xl06
Log10
6.97
6.85
6.99
6.94
6.86
Filtrate
Geometric Mean
(CFU/100 mL)
2
1
<1
2
<1
Log10
0.3
0.0
0.0
0.3
0.0
LRV
6.67
6.85
6.99
6.64
6.86
4.3.3 Choosing LRVc-TEsx from the Individual Sample Point LRV Calculations
Looking back to Table 4-5, the LRV for the feed and filtrate pair at each sample point are given
in the last column of the table. The lowest individual LRV for each module are listed in Table 4-
7. Under this approach, the LRVc-xEsx is 5.99, from Module 4.
Table 4-7. B. atrophaeus LRVc-xEsx from Individual LRVs
Module Number
Module 1
Module 2
Module 3
Module 4
Module 5
LJvVc-TEST
6.35
6.38
6.98
5.99
6.80
14
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4.3.4 B. atrophaeus as a Surrogate for C. parvum
As discussed in Section 3.2, B. atrophaeus was evaluated for use as a surrogate test organism for
C. parvum. Since B. atrophaeus is smaller than Cryptosporidium, it is expected that removal of
the bacteria would be either equal to, or lower than removal of Cryptosporidium. A comparison
of the filtrate sample data in Tables 4-2 and 4-5 shows that while no C. parvum was found in any
samples, B. atrophaeus was detected in filtrate samples for three of the five modules tested. The
LRV for the B. atrophaeus challenges are higher than those for the C. parvum challenges, but
this observation is simply a function of the feed concentrations of the organisms. Therefore, B.
atrophaeus can be considered to be a conservative surrogate for C. parvum.
4.4 MS-2 Challenge Tests
Table 4-8 presents the MS-2 challenge data. All mean feed counts exceeded the target of IxlO4
PFU/mL, except for Module 3 at 30 minutes, which was 9.70xl03 PFU/mL. The maximum
observed overall mean filtrate count was 156 PFU/mL for Module 2. The highest individual
sample filtrate count was 187 PFU/mL from the Module 2 3-minute sample. Under all three
approaches to determine the LRVc-xEsx described below, Module 2 gives the LRVc-xEsx for MS-
2 removal.
Table 4-8. MS-2 Challenge Results
Module 1
Module 2
Module 3
Module 4
Module 5
Sample
Point
Flush
3 Minutes
15 Minutes
30 Minutes
Overall Mean
Flush
3 Minutes
15 Minutes
30 Minutes
Overall Mean
Flush
3 Minutes
15 Minutes
30 Minutes
Overall Mean
Flush
3 Minutes
15 Minutes
30 Minutes
Overall Mean
Flush
3 Minutes
15 Minutes
30 Minutes
Overall Mean
Feed
Geometric Mean
(PFU/mL)
4.3xl04
7.8xl04
7.2xl04
6.2xl04
2.4xl04
1.2xl04
2.2xl04
1.9xl04
1.72xl04
1.54xl04
9.70xl03
1.37xl04
2.7xl04
l.OxlO4
1.40xl04
1.6xl04
3.0xl04
1.3xl04
1.58xl04
l.SxlO4
Log10
4.63
4.89
4.86
4.79
4.38
4.08
4.34
4.26
4.24
4.19
3.99
4.14
4.43
4.00
4.15
4.19
4.48
4.11
4.20
4.26
Filtrate
Geometric Mean
(PFU/mL)
<1
58
88
108
82
<1
187
139
147
156
<1
66
50
8
30
<1
42
55
30
41
<1
101
104
61
86
Log10
1.76
1.95
2.03
1.91
2.27
2.14
2.17
2.19
1.82
1.69
0.91
1.48
1.62
1.74
1.47
1.61
2.00
2.02
1.79
1.93
LRV
2.87
2.94
2.83
2.88
2.11
1.94
2.17
2.07
2.42
2.50
3.08
2.65
2.81
2.26
2.68
2.57
2.48
2.09
2.41
2.32
15
-------
4.4.1 Choosing LRVC-xEsx from the Averages of the Individual LRV Calculations
In Table 4-8, the LRV numbers in the "Overall Mean" rows are the geometric mean calculations
of the individual sample point LRV for each module. Using this approach, the lowest LRV, and
thus the LRVc-TEsx, is 2.07 for Module 2.
4.4.2 LRVc-TEsx Calculated from the Mean Feed and Filtrate Counts
Using this approach, each overall mean feed and filtrate count needs to be log transformed. In
most cases these log values will be equal to the overall mean log values presented in Table 4-8 as
the mean of the individual logic values. However, in some instances, the log of the overall mean
feed or filtrate count will differ slightly from that calculated from the individual log values. The
log transformations of the overall mean feed and filtrate counts are presented in Table 4-9.
Under this approach, the LRV for Modules 2, 3, 4, and 5 differ from the approach in Section
4.4.1. Module 2 still gives the LRVC.TEST, at 2.08.
Table 4-9. MS-2 LRVC-xEsx Calculated from the Mean Feed and Filtrate Counts
Module Number
Module 1
Module 2
Module 3
Module 4
Module 5
Feed
Geometric Mean
(PFU/mL)
6.2xl04
1.9xl04
1.37xl04
1.6xl04
l.SxlO4
Log10
4.79
4.27
4.14
4.19
4.26
Filtrate
Geometric Mean
(PFU/mL)
82
156
30
41
86
Log10
1.91
2.19
1.48
1.61
1.93
LRV
2.88
2.08
2.66
2.58
2.33
4.4.3 Choosing LRVc-xEsx from the Individual Sample Point LRV Calculations
Looking back to Table 4-8, the LRVs for the feed and filtrate pair at each sample point are given
in the last column of the table. The lowest individual LRV for each module are listed in Table 4-
10. Under this approach, the LRVc-xEsx is 1.94, from Module 2.
Table 4-10. MS-2 LRVC-xEsx from Individual LRVs
Module Number
Module 1
Module 2
Module 3
Module 4
Module 5
LRVc-TEST
2.83
1.94
2.42
2.26
2.09
16
-------
4.5 Operational Data and Water Quality Data for All Challenges
The pilot unit operational data is presented in Table 4-11. The filtrate flow rates were above the
target flow rate of 14 gpm for all of the MS-2 and B. atrophaeus challenges, but this may have
been due to the pilot unit's internal flow meter being inaccurate. The flow rate had to be
controlled at 14 gpm using the pilot unit's PLC, which was receiving flow rate data from the
internal flow meter. However, the flow rate measurements were taken on the filtrate line outside
the pilot unit using a laboratory flow meter that had been calibrated prior to the start of testing.
The feed and filtrate pressure measurements were made using the existing pressure transducers
on the pilot unit. The accuracy of these transducers was verified by an NSF Calibration Officer
prior to testing. Note that the feed and filtrate pressures were much higher for the C. parvum
challenges than for the MS-2 and B. atrophaeus challenges. The pilot unit controlled the applied
pressure on the membranes. It is not known why this occurred. The testing engineer did not
note any changes in the operation of the pilot unit prior to the C. parvum challenges. The
Module 3 MS-2 retest was conducted the morning of 05/21/08, and the feed pressure was
approximately 12 psig. The first C. parvum challenge, that for Module 3, was conducted during
the afternoon of 05/21/08, and the start-up feed pressure was 26.7 psig. Siemens does not give a
maximum feed pressure on the specifications sheet for the L10V module, only a maximum trans-
membrane pressure of 21.7 psig, which was not exceeded at any time during testing. In any
event, the higher feed pressure did not appear to affect membrane performance, since all filtrate
samples were clear of C. parvum.
Table 4-11. Operation Data
Module #
Date
Filtrate Flow Rate
(gpm)
OMin.
30 Min.
Flux
(gfd)
OMin | 30 Min
Feed Pressure
(psig)
OMin.
30 Min.
Filtrate Pressure
(psig)
OMin.
30 Min.
MS-2 Challenges
Module 1
Module 2
Module 3
Module 4
Module 5
05/13/08
05/19/08
05/21/08
05/15/08
05/15/08
14.10
14.65
14.40
14.45
14.57
14.37
14.14
14.14
14.42
14.24
80.6
83.7
82.3
82.6
83.3
82.1
80.8
80.8
82.4
81.4
10.4
13.3
12.3
12.7
11.4
10.5
12.4
11.6
12.2
10.7
6.1
6.5
6.4
6.7
6.5
6.1
5.8
5.8
6.2
5.9
B. atrophaeus Challenges
Module 1
Module 2
Module 3
Module 4
Module 5
05/16/08
05/16/08
05/16/08
05/15/08
05/15/08
14.47
14.09
14.26
14.58
14.70
14.06
14.04
14.24
14.29
14.57
82.7
80.5
81.5
83.3
84.0
80.3
80.2
81.4
81.7
83.3
10.3
13.0
12.0
12.5
11.7
10.5
12.7
12.0
12.0
10.9
6.1
6.4
6.1
6.6
6.8
6.0
6.0
6.1
5.9
6.0
C. parvum Challenges
Module 1
Module 2
Module 3
Module 4
Module 5
05/28/08
05/28/08
05/21/08
05/22/08
05/27/08
14.34
13.89
14.07
14.06
13.93
14.24
13.89
13.96
13.97
13.89
81.9
79.4
80.4
80.3
79.6
81.4
79.4
79.8
79.8
79.4
26.2
26.1
26.7
26.1
25.8
26.2
27.3
24.8
26.5
25.8
22.0
20.0
21.3
20.7
21.4
21.9
21.1
19.4
20.8
21.5
17
-------
The water chemistry data is displayed in Table 4-12. Of the water quality parameters reported,
only alkalinity and pH had target ranges specified in the test/QA plan. All alkalinity
measurements were within the target range of 100 ฑ 10 mg/L. Four of the pH measurements
were above the maximum target pH of 8.0. The maximum observed pH was 8.30 for the Module
4 MS-2 challenge.
Table 4-12. Water Chemistry Data
Module #
Date
Alkalinity
(mg/L
CaC03)
PH
Temp. (ฐC)
Total
Chlorine
(mg/L)
TDS (mg/L)
Turbidity
(NTU)
MS-2 Challenges
Module 1
Module 2
Module 3
Module 4
Module 5
05/13/08
05/19/08
05/21/08
05/15/08
05/15/08
100
96
100
100
100
8.21
7.81
7.90
8.30
8.28
23.2
23.1
23.8
22.8
23.1
0.05
0.05
0.05
0.05
0.05
110
100
110
110
120
0.19
0.17
0.11
0.11
0.19
B. atrophaeus Challenges
Module 1
Module 2
Module 3
Module 4
Module 5
05/16/08
05/16/08
05/16/08
05/15/08
05/15/08
100
99
98
100
110
7.79
7.77
7.81
8.00
8.26
22.9
22.8
22.6
23.5
23.2
0.05
0.05
0.05
0.05
0.05
110
110
110
130
120
0.15
0.12
0.09
0.16
0.19
C. parvum Challenges
Module 1
Module 2
Module 3
Module 4
Module 5
05/28/08
05/28/08
05/21/08
05/22/08
05/27/08
94
94
96
91
96
7.71
7.74
7.46
7.44
7.54
23.2
23.6
23.0
23.7
25.5
0.05
0.05
0.05
0.05
0.05
100
110
110
110
100
0.12
0.12
0.16
0.13
0.20
18
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Chapter 5
Quality Assurance/Quality Control
5.1 Introduction
An important aspect of verification testing is the QA/QC procedures and requirements. Careful
adherence to the procedures ensured that the data presented in this report was of sound quality,
defensible, and representative of the equipment performance. The primary areas of evaluation
were representativeness, accuracy, precision, and completeness.
Because this ETV was conducted at the NSF testing lab, all laboratory activities were conducted
in accordance with the provisions of the NSF International Laboratories Quality Assurance
Manual.
5.2 Test Procedure QA/QC
NSF testing laboratory staff conducted the tests by following a USEPA-approved test/Q A plan
created specifically for this verification (Appendix A). NSF QA Department staff performed an
audit during testing to ensure the proper procedures were followed. The audit yielded no
significant findings.
5.3 Sample Handling
All samples analyzed by the NSF Chemistry and Microbiology Laboratories were labeled with
unique identification numbers. All samples were analyzed within allowable holding times.
5.4 Chemistry Laboratory QA/QC
The calibrations of all analytical instruments and the analyses of all parameters complied with
the QA/QC provisions of the NSF International Laboratories Quality Assurance Manual.
The NSF QA/QC requirements are all compliant with those given in the USEPA method or
Standard Method for the parameter. Also, every analytical method has an NSF standard
operating procedure.
5.5 Microbiology Laboratory QA/QC
5.5.1 Growth Media Positive Controls
All media were 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 was an absence of growth in the positive response check.
5.5.2 Negative Controls
For each sample batch processed, an unused membrane filter and a blank with 100 mL of
buffered, sterilized dilution water was filtered through the membrane were also placed onto the
19
-------
appropriate media and incubated with the samples as negative controls. No growth was observed
on any blanks.
5.6 Documentation
All laboratory activities were documented using specially prepared laboratory bench sheets and
NSF laboratory reports. Data from the bench sheets and laboratory reports were entered into
Microsoft Excelฎ spreadsheets. These spreadsheets were used to calculate the geometric
means and logic reductions. One hundred percent of the data entered into the spreadsheets was
checked by a reviewer to confirm all data and calculations were correct.
5.7 Data Review
NSF QA/QC staff reviewed the raw data records for compliance with QA/QC requirements. As
required in the ETV Quality Management Plan, NSF ETV staff checked at least 10% of the data
in the NSF laboratory reports against the lab bench sheets.
5.8 Data Quality Indicators
The quality of data generated for this ETV is established through four indicators of data quality:
representativeness, accuracy, precision, and completeness.
5.8.1 Representativeness
Representativeness refers to the degree to which the data accurately and precisely represent the
expected performance of the UF membranes under normal use conditions. The membrane
modules were tested in a Siemens pilot unit, at the flux specified by Siemens.
Representativeness was ensured by consistent execution of the test protocol for each challenge,
including timing of sample collection, sampling procedures, and sample preservation.
Representativeness was also ensured by using each analytical method at its optimum capability
to provide results that represent the most accurate and precise measurement it is capable of
achieving.
5.8.2 Accuracy
Accuracy was quantified as the percent recovery of the parameter in a sample of known quantity.
Accuracy was measured through use of both matrix spikes of a known quantity and certified
standards during calibration of an instrument.
The following equation was used to calculate percent recovery:
Percent ReCOVery = 100 X [(Xknown - Xmeasured)/Xknown]
where: Xkn0wn = known concentration of the measured parameter
= measured concentration of parameter
20
-------
Accuracy of the bench-top chlorine, pH, and turbidity meters was checked daily during the
calibration procedures using certified check standards. Alkalinity and TDS were analyzed in
batches. Certified QC standards and/or matrix spikes were run with each batch.
The percent recoveries of all matrix spikes and standards were within the allowable limits for all
analytical methods.
5.8.3 Precision
Precision refers to the degree of mutual agreement among individual measurements and provides
an estimate of random error. One sample per batch was analyzed in duplicate for the TDS
measurements. At least one out of every ten samples for alkalinity was analyzed in duplicate.
Duplicate municipal drinking water samples were analyzed for pH, total chlorine, and turbidity
as part of the daily calibration process. Precision of duplicate analyses was measured by use of
the following equation to calculate RPD:
RPD =
x200
where:
S1 = sample analysis result; and
(5*2 = sample duplicate analysis result.
All RPD were within NSF's established allowable limits for each parameter. Please note that
samples from this evaluation for alkalinity and TDS were batched with other non-ETV samples.
The duplicate analysis requirements apply to the whole batch, not just the samples from this
ETV.
5.8.4 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, as presented in Table 5-1.
Table 5-1. Completeness Requirements
Number of Samples per Parameter and/or Method
0-10
11-50
>50
Percent Completeness
80%
90%
95%
21
-------
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.
All planned samples were collected for challenge organism and water chemistry analysis. One
planned pressure decay test out of 30 was not conducted - the post-challenge pressure decay test
for the Module 5 C. parvum challenge. This gives a completeness percentage of 97, which meets
the completeness requirement in Table 5-1.
22
-------
Chapter 6
References
APHA, AWWA, and WEF (2005). Standard Methods for the Examination of Water and
Wastewater, 21st Edition.
NSF International (2007). NSF/ANSI Standard 55 - Ultraviolet Microbiological Water
Treatment Systems.
USEPA (2005). Membrane Filtration Guidance Manual (EPA 815-R-06-009).
USEPA and NSF International (2005). ETVProtocolfor Equipment Verification Testing for
Physical Removal of Microbiological and Paniculate Contaminants
23
-------
Appendix A
Test/Quality Assurance Project Plan
Contact Mr. Bruce Bartley at 734-769-5148 or bartley@nsf.org for a copy of this document.
A-l
-------
Appendix B
Bacillus Endospores as a Surrogate for C. parvum Oocysts
The EPA LT2ESWTR allows the use of a surrogate for C. parvum, provided the surrogate is
conservative. The EPA MFGM specifically discusses Bacillus subtilis as a surrogate, but states
"Because there is limited data currently available regarding the use of Bacillus subtilis in
membrane challenge studies, a characterization of this organism would be necessary to
determine whether it could be used as a Cryptosporidium surrogate..." The MFGM also states
"Based on the size.. .Bacillus subtilis could potentially be considered a conservative
surrogate.. .pending a comparison of other characteristics (e.g., shape, surface charge, etc.)..."
1. Organism Size and Shape
C. parvum is spherical in shape, while Bacillus endospores are ellipsoidal in shape (football
shaped). C. parvum has a diameter of 4-6 jim. Bacillus endospores are approximately 0.8 jim in
diameter, and 1.8 jim in length. Therefore, Bacillus endospores are a conservative surrogate for
C. parvum, no matter what the orientation of the endospore is when it impacts the test
membrane.
Baltus et. al. (2008) studied membrane rejection of bacteria and viruses with different length vs.
diameter aspect ratios. They theorized, based on a transport model for rod-shaped particles, that
rejection would improve as the aspect ratio (length vs. diameter) increased for a fixed particle
volume. However, their experimental results contradicted this, with similar rejection rates for
particles with a range of aspect ratios. The model assumed that particles would impact the
membrane with equal frequency for all particle orientations. They theorize that instead, an end-
on orientation was favored for transport of the particles in the water stream. They concluded that
microorganism removal by membranes could be conservatively estimated using only the rod
diameter in transport models. These findings add an additional safety factor to using Bacillus
endospores as a surrogate for C. parvum.
2. Electrophoretic Mobility and Isoelectric Point
A suitable surrogate should have a surface charge similar to C. parvum, as measured through the
isoelectric point and electrophoretic mobility (EPM). The isoelectric point is the pH at which the
particle has a neutral surface charge in an aqueous environment. Below this point the particle
has a net positive charge, above it a net negative charge. Many studies have pegged the
isoelectric point of C. parvum between pH values of 2 and 4, thus it would have a negative
surface charge in the neutral pH range. The isoelectric point can be found by measuring the
EPM of the particle at various pH values. The pH where the EPM is zero is classified as the
isoelectric point.
Lytle et. al. (2002) measured the EPM of both C. parvum and B. subtilis endospores in solutions
of increasing buffer concentration (0.915 millimolar (mM) 9.15 mM, and 91.5 mM KH2PO4).
They found that increasing the buffer concentration also increases the EPM toward a positive
value. The buffer concentration of the test water for the Siemens tests was approximately 1 mM.
Therefore, the 0.915 mM data from this study should be the most accurate representation of the
B-l
-------
C. parvum and B. subtilis EPM for the ETV tests. In 0.915 mM solutions at pH values between
7 and 8, they observed EPM of approximately -2.2 to -2.6 jim cm V"1 s"1 for C. parvum, and -1.9
to -2.2 |im cm V'V1 for B. subtilis. For B. subtilis, the researchers did not measure an isoelectric
point at any buffer concentration. For C. parvum, they did find an isoelectric point at a pH
around 2.5, but only for the 9.15 mM solution. For both organisms, the 0.915 mM solution
generally gave lower (more negative) EPM values than the solutions with higher buffering
capacity.
3. Aggregation
The NSF Microbiology Laboratory microscopically examined a sample of the B. atrophaeus
stock solutions purchased for the tests. The sample was suspended in sterile, buffered, deionized
water and stirred at moderate speed for 15 minutes. The estimated cell density was IxlO9
CFU/100 mL, which is approximately 100 times higher than the suspensions injected into the
pilot units to challenge the UF membranes. Figure 1 is a photograph of the B. atrophaeus
endospores in the sample. The magnification is lOOOx oil immersion with differential
interference contrast microscopy. No evidence of endospore aggregation was found.
Figure B-l. Mono-dispersed B. atrophaeus endospores used for challenge tests.
B-2
-------
References
Baltus, R. E., A. R. Badireddy, W. Xu, and S. Chellam (2009). Analysis of Configurational
Effects on Hindered Convection of Nonspherical Bacteria and Viruses across Microfiltration
Membranes. Industrial and Engineering Chemistry Research. In press.
Brush, C. F., M. F. Walter, L. J. Anguish, and W. C. Ghiorse (1998). Influence of Pretreatment
and Experimental Conditions on Electrophoretic Mobility and Hydrophobicity of
Cryptosporidium parvum Oocysts. Applied and Environmental Microbiology. 64: 4439-4445.
Butkus, M. A., J. T. Bays, and M. P. Labare (2003). Influence of Surface Characteristics on the
Stability of Cryptosporidium parvum Oocysts. Applied and Environmental Microbiology. 69:
3819-3825.
Lytle, D. A., C. H. Johnson, and E. W. Rice (2002). A Systematic Comparison of the
Electrokinetic Properties of Environmentally Important Microorganisms in Water. Colloids and
Surfaces B: Biointerfaces. 24: 91-101.
B-3
-------
Appendix C
Challenge Organism Triplicate Counts
Table C-l. MS-2 Triplicate Count Data
Module
Module 1
Module 2
Module 3
Module 4
Module 5
Sample
Flush
3 Minutes
1 5 Minutes
30 Minutes
Flush
3 Minutes
1 5 Minutes
30 Minutes
Flush
3 Minutes
1 5 Minutes
30 Minutes
Flush
3 Minutes
1 5 Minutes
30 Minutes
Flush
3 Minutes
1 5 Minutes
30 Minutes
Feed (PFU/mL)
Count 1
4.8E+04
7.3E+04
6.2E+04
2.10E+04
1.20E+04
1.60E+04
1.37E+04
1.46E+04
7.50E+03
2.8E+04
8.7E+03
1.19E+04
2.6E+04
9.2E+03
1.11E+04
Count 2
3.3E+04
9.0E+04
6.8E+04
3.30E+04
1.30E+04
1.80E+04
1.60E+04
1.44E+04
9.50E+03
3.3E+04
1.12E+04
1.46E+04
3.2E+04
9.6E+03
1.42E+04
Count 3
4.9E+04
7.2E+04
8.8E+04
1.90E+04
l.OOE+04
3.70E+04
2.34E+04
1.74E+04
1.29E+04
2.2E+04
1.16E+04
1.59E+04
3.1E+04
2.23E+04
2.48E+04
Filtrate (PFU/mL)
Count 1
<1
58
93
192
<1
222
135
131
<1
49
28
3
<1
48
50
42
<1
101
79
45
Count 2
<1
45
104
141
<1
142
155
147
<1
58
62
10
<1
35
81
26
<1
68
88
41
Count 3
<1
74
71
46
<1
209
129
164
<1
103
70
18
<1
43
42
24
<1
148
162
123
Table C-2. B. atrophaeus Triplicate Count Data
Module
Module 1
Module 2
Module 3
Module 4
Module 5
Sample
Flush
3 Minutes
15 Minutes
30 Minutes
Flush
3 Minutes
15 Minutes
30 Minutes
Flush
3 Minutes
15 Minutes
30 Minutes
Flush
3 Minutes
15 Minutes
30 Minutes
Flush
3 Minutes
15 Minutes
30 Minutes
Feed (CFU/mL)
Count 1
9.2E+06
8.4E+06
8.7E+06
3.5E+06
7.6E+06
8.2E+06
l.OE+07
9.3E+06
9.3E+06
1.17E+07
6.7E+06
9.4E+06
6.5E+06
7.0E+06
7.1E+06
Count 2
l.OE+07
9.4E+06
9.5E+06
7.5E+06
7.0E+06
8.3E+06
1.1E+07
l.OE+07
1.1E+07
1.02E+07
7.1E+06
9.5E+06
6.1E+06
7.5E+06
7.8E+06
Count 3
1.1E+07
l.OE+07
8.9E+06
8.4E+06
7.9E+06
7.9E+06
9.0E+06
1.1E+07
8.7E+06
1.06E+07
5.1E+06
l.OE+07
6.3E+06
7.7E+06
9.3E+06
Filtrate (CFU/lOOmL)
Count 1
<1
1
3
5
<1
<1
2
<1
<1
<1
<1
<1
2
<1
9
7
<1
<1
<1
<1
Count 2
1
3
<1
6
<1
<1
4
<1
<1
<1
<1
<1
1
<1
6
1
<1
<1
<1
<1
Count 3
1
3
<1
2
<1
<1
2
<1
<1
<1
<1
<1
<1
<1
4
2
<1
<1
<1
<1
C-l
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Table C-3. C. parvum Triplicate Count Data
Module
Module 1
Module 2
Module 3
Module 4
Module 5
Sample
Flush
3 Minutes
15 Minutes
30 Minutes
Flush
3 Minutes
15 Minutes
30 Minutes
Flush
3 Minutes
15 Minutes
30 Minutes
Flush
3 Minutes
15 Minutes
30 Minutes
Flush
3 Minutes
15 Minutes
30 Minutes
Feed (oocysts/L)
Count 1
4.4E+05
5.9E+05
5.7E+05
3.8E+05
7.3E+05
6.7E+05
5.2E+05
7.3E+05
4.8E+05
4.0E+05
4.8E+05
5.0E+05
4.7E+05
3.8E+05
5.7E+05
Count 2
7.0E+05
9.3E+05
4.6E+05
2.8E+05
3.9E+05
5.1E+05
3.7E+05
4.6E+05
4.2E+05
4.5E+05
5.2E+05
4.2E+05
5.9E+05
4.7E+05
5.0E+05
Count 3
7.0E+05
7.8E+05
7.0E+05
3.2E+05
6.8E+05
5.8E+05
5.6E+05
5.8E+05
3.3E+05
6.0E+05
4.2E+05
4.8E+05
5.0E+05
5.8E+05
4.6E+05
Filtrate (oocysts/L)
Count 1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
Count 2
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
Count 3
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
C-2
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