September 2009
NSF 09/31/EPADWCTR
EPA/600/R-09/108
Environmental Technology
Verification Report
Removal of Microbial Contaminants in
Drinking Water
Siemens Corporation
Memcor® L20V 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: MEMCOR® L20V 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 Memcor® L20V ultrafiltration (UF)
module for removal of microbial contaminants under controlled laboratory challenge conditions. The
challenge tests were conducted atNSF's testing laboratory in Ann Arbor, MI. Testing of the Siemens
Memcor® L20V ultrafiltration 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 09/31/EPADWCTR The accompanying notice is an integral part of this verification statement. September 2009
VS-i
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ABSTRACT
The Siemens Memcor L20V UF module was tested for removal of 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). B. atrophaeus served as a surrogate for
Cryptosporidium oocysts. Five modules from five different production lots were challenged with both
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 L20V equates to approximately 22.8
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-iEsi) 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
B. atrophaeus
MS2
Method 1
6.89
2.49
Method 2
6.89
2.50
Method 3
6.81
2.22
PRODUCT DESCRIPTION
The Memcor L20V UF membrane module is a member of the Memcor XP line of products. The module
measures 4.7 inches in diameter by 70.9 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 L20V modules were tested for removal of microorganisms using endospores of the bacteria Bacillus
atrophaeus (ATCC 9372, deposited as Bacillus subtilis var. niger), and MS-2 coliphage virus (ATCC
15597-B1). B. atrophaeus served as a surrogate for Cryptosporidium oocysts, as well as other bacteria.
B. atrophaeus endospores are ellipsoidal (football shaped), with an average diameter of 0.8 (im, and an
average length of 1.8 (im. A full discussion of the rationale for using Bacillus endospores as a surrogate
for Cryptosporidium can be found in the verification report. 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 nm in diameter. Separate challenge tests were conducted for each
challenge organism, so each module was tested twice 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
NSF 09/31/EPADWCTR
The accompanying notice is an integral part of this verification statement. September 2009
VS-ii
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was added in sufficient quantity to provide alkalinity at a target of 100 ± 10 mg/L as calcium carbonate.
The pH was then lowered with hydrochloric acid to a target range of 7.5 ± 0.5.
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 Particulate 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 22.8 gallons per minute (gpm) for the L20V
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 for five-minute periods using a peristaltic pump at each sampling point. The injection
point was downstream of the pilot unit's feed tank, as shown in Figure 2-1. 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. At the end of each challenge test, a second
pressure decay test was conducted to confirm membrane integrity.
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 equilibirum
(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 CP pilot unit with only one membrane cartridge in place is 8 gallons,
not including the unit's feed tank. The microbial challenges were conducted at approximately 22.8 gpm,
so over 68 gallons of spiked feed water passed through the membranes prior to sample collection, well
over the equilibrium volume.
VERIFICATION OF PERFORMANCE
The LT2ESWTR and MFGM specify that an 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
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).
NSF 09/31/EPADWCTR The accompanying notice is an integral part of this verification statement. September 2009
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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 0.08 psig/min, indicating that there were no membrane integrity
issues during the tests.
B. atrophaeus Reduction
The LT2ESWTR indicates a maximum challenge concentration to achieve a reduction of 6.5 logic
(3.16xl06 CFU/100 mL). The B. atrophaeus feed concentrations for these tests ranged from 6.5xl06 to
1.7xl07 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.TEST for each method is in bold font. The LT2ESWTR specifies
that the maximum possible LRVc-iEsi awarded to a membrane product is 6.5 logic, but the LRV above
6.5 are still presented here.
No B. atrophaeus endospores were found in any of the filtrate samples for the Modules 1 and 2, but B.
atrophaeus at only 1 CFU/100 mL was found in some of the filtrate samples for Modules 3, 4, and 5.
Endospores were also found in the flush samples for Modules 3 and 4, at 1 and 3 CFU/100 mL,
respectively. Therefore, the observed filtrate counts could be due to low level contamination of the pilot
unit by the challenge organism. Since all filtrate samples were either 1 or <1 CPU, the filtrate log
transformations are all 0.0. This makes the LRV simply a function of the log of the challenge
concentration. The flow rates measured during the B. atrophaeus challenges translated into fluxes
ranging from 79.5 to 80.9 gfd.
Table VS-ii. B. atrophaeus LRV Calculations
Module #
Module 1
Module 2
Module 3
Module 4
Module 5
Method 1
6.89(1)
6.90
6.91
7.00
7.07
Method 2
6.89(1)
6.90
6.91
7.00
7.07
Method 3
6.81(1)
6.89
6.90
6.99
6.97
(1) LRVc-TEsi under these two methods should be capped at 6.5.
MS-2 Reduction
The MS-2 feed concentrations ranged from 2.5xl04 PFU/mL to 7.4xl04 PFU/mL. The LRV for MS-2
reduction are shown in Table VS-iii. The LRVc-TEST for each method is in bold font. The maximum
individual filtrate count was 212 PFU/mL for Module 2 at start-up. The flow rates measured during the
MS-2 challenges translated into fluxes ranging from 79.2 to 80.6 gfd.
Table VS-iii. MS-2 LRV Calculations
Module #
Module 1
Module 2
Module 3
Module 4
Module 5
Method 1
3.26
2.58
2.49
2.70
2.84
Method 2
3.28
2.58
2.50
2.70
2.84
Method 3
2.84
2.32
2.22
2.39
2.65
NSF 09/31/EPADWCTR
The accompanying notice is an integral part of this verification statement. September 2009
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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 Original signed by Robert Ferguson 11/05/09
Sally Gutierrez Date Robert Ferguson Date
Director Vice President
National Risk Management Research Water Systems
Laboratory NSF International
Office of Research and Development
United States Environmental Protection
Agency
NOTICE: Verifications are based on an evaluation of technology performance under specific,
predetermined criteria and the appropriate quality assurance procedures. EPA and NSF make no
expressed or implied warranties as to the performance of the technology and do not certify that a
technology will always operate as verified. The end-user is solely responsible for complying with
any and all applicable federal, state, and local requirements. Mention of corporate names, trade
names, or commercial products does not constitute endorsement or recommendation for use of
specific products. This report is not an NSF Certification of the specific product mentioned
herein.
Availability of Supporting Documents
Copies of the test protocol, the verification statement, and the verification report (NSF
report # NSF 09/31/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 09/31/EPADWCTR The accompanying notice is an integral part of this verification statement. September 2009
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September 2009
Environmental Technology Verification Report
Removal of Microbial Contaminants in Drinking Water
Siemens Corporation
Memcor® L20V 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 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 vi
Abbreviations and Acronyms vii
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 L20V 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 B. atrophaeus Challenge Tests 11
4.2.1 Choosing LRVc-xEsx from the Averages of the Individual LRV Calculations 11
4.2.2 LRVc-TEsx Calculated from the Mean Feed and Filtrate Counts 11
4.2.3 Choosing LRVc-xEsx from the Individual Sample Point LRV Calculations 11
4.3 MS-2 Challenge Tests 12
4.3.1 Choosing LRVc-xEsx from the Averages of the Individual LRV Calculations 13
4.3.2 LRVc-xEsx Calculated from the Mean Feed and Filtrate Counts 13
4.3.3 Choosing LRVc-xEsx from the Individual Sample Point LRV Calculations 14
4.4 Operational Data and Water Quality Data for All Challenges 14
Chapter 5 Quality Assurance/Quality Control 16
5.1 Introduction 16
5.2 Test Procedure QA/QC 16
5.3 Sample Handling 16
5.4 Chemistry Laboratory QA/QC 16
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5.5 Microbiology Laboratory QA/QC 16
5.5.1 Growth Media Positive Controls 16
5.5.2 Negative Controls 16
5.6 Documentation 17
5.7 Data Review 17
5.8 Data Quality Indicators 17
5.8.1 Representativeness 17
5.8.2 Accuracy 17
5.8.3 Precision 18
5.8.4 Completeness 18
Chapter 6 References 20
Appendices
Appendix A Test/Quality Assurance Proj ect Plan
Appendix B Bacillus Endospores as a Surrogate for C. parvum Oocysts
Appendix C Triplicate Challenge Organism Counts
List of Tables
Table 2-1. L20V 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 10
Table 4-2. B. atrophaeus Challenge Results 12
Table 4-3. B. atrophaeus LRVc-xEsx from Individual LRVs 12
Table 4-4. MS-2 Challenge Results 13
Table 4-5. MS-2 LRVC-xEsx Calculated from the Mean Feed and Filtrate Counts 14
Table 4-6. MS-2 LRVC-xEsx from Individual LRVs 14
Table 4-7. Operation Data 15
Table 4-8. Water Chemistry Data 15
Table 5-1. Completeness Requirements 18
List of Figures
Figure 2-1. Siemens Memcor CP pilot unit 4
VI
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Abbreviations and Acronyms
ATCC American Type Culture Collection
°C degrees Celsius
CPU colony forming units
cm centimeter
DWS Drinking Water Systems
EPM Elecgtrophoretic Mobility
ETV Environmental Technology Verification
°F degrees Fahrenheit
ft foot(feet)
gfd gallons per square foot per day
gpm gallons per minute
in inch
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
vn
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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 Memcor® L20V 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 L20V Membrane Module Description
The Memcor L20V UF membrane module is a member of the Memcor CP line of products. The
module measures 4.7 inches in diameter by 70.9 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. L20V 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))
70.9 in (1800 mm)
0.04 urn
0.1 urn
410 square feet (ft2) (38 square meters (m2))
>32 - 104 Fahrenheit (°F) (>0 - 40 Celcius (°C))
113°F(45°C)
21.7 pounds per square inch, gauge (psig) (150 kilopascals (kPa))
2-10
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Table 2-2. Serial Numbers of Tested Modules
Module
1
2
3
4
5
Batch Number
32893
11207
32879
33340
33272
Identification Number
WJ790145
WK7AU519
WK79K74W
WJ7AR22M
WK7AJ62G
Serial Number
388733
394401
388250
393995
392393
2.3 Pilot Unit Used for Testing
Siemens supplied a pilot unit for testing along with the membrane cartridges. A photo of a
representative pilot unit is shown below as Figure 2-1. The pilot unit holds two membrane
cartridges, but only one cartridge was tested at a time. The valves allowing water to pass
through the other cartridge housing was 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.
location of injection port
location of feed sample tap
Figure 2-1 Siemens Memcor CP pilot unit.
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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 accuracy of the flow meter
was verified 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, as shown in Figure 2-1.
The distance between the two points was not measured, but it was assumed that the feed pump
provided sufficient mixing of the water.
-------
Chapter 3
Methods and Procedures
3.1 Introduction
The challenge tests were conducted in July 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 L20V modules were tested for removal of microorganisms using the MS-2 coliphage virus,
and endospores of the bacteria Bacillus atrophaeus (American Type Culture Collection, ATCC
number 9372, deposited as Bacillus subtilis var. niger). B. atrophaeus was used as a surrogate
for Cryptosporidium parvum and other protozoan oocysts. 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 jim, and
an average length of 1.8 |im. The LT2ESWTR allows the use of a surrogate for C. parvum for
challenge testing to obtain C. parvum removal credits, provided the surrogate is conservative.
The suitability of using B. atrophaeus as a surrogate for Cryptosporidium was demonstrated in
the ETV verification testing of the Siemens L10V module. For that verification test, no C.
parvum was detected in the filtrate samples for any of the five different modules tested, but B.
atrophaeus was detected in the filtrate samples for three of the five modules, albeit at less than
1.0 logic per 100 mL. 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); and
• B. atrophaeus - IxlO6 to 5xl06 colony forming units (CPU) per lOOmL.
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.
The MS-2 stock suspension was purchased from Biological Consulting Services of North
Florida, Inc. B. atrophaeus was purchased from Presque Isle Cultures.
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 25°C;
• 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 ± 10 mg/L as calcium
carbonate. The pH was then lowered with hydrochloric acid to a target range of 7.5 ± 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 two 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 housing was
closed off. The target flux for membrane operation was 80 gallons per square foot per day (gfd)
at 20 °C, which, for the L20V, equals a flow rate of 22.8 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
twice. 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 22.8 gpm if necessary, and collected a flush sample 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 for five-minute periods using a peristaltic pump at
each sampling point. The injection point was downstream of the pilot unit's feed tank, as shown
in Figure 2-1. 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. At the end of each challenge test, a second pressure decay test was conducted to
confirm membrane integrity.
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 CP pilot unit with
only one membrane cartridge in place is 8 gallons, not including the unit's feed tank. The
microbial challenges were conducted at approximately 22.8 gpm, so over 68 gallons of spiked
feed water passed through the membranes prior to sample collection, well over the equilibrium
volume.
3.6 Analytical Methods
A list of laboratory analytical methods can be found in Table 3.1. All samples for MS-2 and B.
atrophaeus and 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
Method
USEPA310.2
SM2 4500-H+
SM 2540 C
SM 4500-C1 G
SM2130
NSF 555
SM92186
NSF
Reporting
Limit
5mg/L
NA
5mg/L
0.05 mg/L
0.1 NTU4
1 PFU/mL
1 CFU/100 mL
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
(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 July 24, 2008 to July 30, 2008. One module was tested
per day, with separate 30-minute challenge tests each for MS-2 and B. atrophaeus.
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 also logic 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 three triplicate counts were non-detect for the
organism. 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 0.08 psig/min, indicating that there were no membrane integrity issues
during the tests.
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
0.07
0.06
0.08
0.07
0.07
Post-Test
0.06
0.07
0.06
0.06
0.07
B. atrophaeus Pressure Decay Data (psig/min)
Pre-Test
0.06
0.07
0.06
0.06
0.07
Post-Test
0.06
0.06
0.07
0.06
0.07
10
-------
4.2 B. atrophaeus Challenge Tests
The B. atrophaeus challenge results are displayed in Table 4-2. 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 logic (3.16xl06 CFU/100 mL), so that the
maximum LRVc-xEsx awarded to a membrane product is 6.5 logio. The B. atrophaeus feed
concentrations for these tests ranged from 6.5xl06 to 1.7xl07 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 any of the filtrate samples for Modules 1 and 2, but one endospore
was found in the Module 3 30-minute sample, and one endospore per sample was found for all of
the Module 4 and 5 filtrate samples. Endospores were also found in the flush samples for
Modules 3 and 4, at 1 and 3 CFU/100 mL, respectively. The modules were tested in order from
1 to 5, so the fact that all of the Module 1 and 2 filtrate samples were clean, but not those for
Modules 3, 4, and 5 suggests that perhaps the pilot unit became contaminated during the module
change-outs. Even though endospores were detected in the filtrate samples, the counts of only 1
CFU/lOOmL give logic transformations of 0.0. This makes the LRV values a function of the
feed concentration. All LRV 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 LRV above 6.5 are still presented here.
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 LRVs for each module. Using this approach, the lowest LRV, and
thus the LRVc-xEsx, is 6.89 for Module 1.
4.2.2 LRVc-xEsx 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. For the B. atrophaeus tests, all of the log transformations of the mean feed and filtrate
counts (data not shown) equaled the overall mean log values shown in Table 4-2. Therefore,
LRVc-xEsx under this approach is also 6.89, from Module 1.
4.2.3 Choosing LRVc-xEsx from the Individual Sample Point LRV Calculations
In 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 4-3. Under
this approach, the LRVc-xEsx is 6.81, from Module 1.
11
-------
Table 4-2. 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)
—
6.5xl06
S.lxlO6
8.9xl06
7.8xl06
—
7.8xl06
7.7xl06
8.4xl06
S.OxlO6
—
8.4xl06
S.lxlO6
7.9xl06
S.lxlO6
—
l.OxlO7
l.OxlO7
9.7xl06
9.9xl06
—
1.7xl07
l.OxlO7
9.4xl06
1.2xl07
Log10
—
6.81
6.91
6.95
6.89
—
6.89
6.89
6.92
6.90
—
6.92
6.91
6.90
6.91
—
7.00
7.00
6.99
7.00
—
7.23
7.00
6.97
7.07
Filtrate
Geometric Mean
(CFU/100 mL)
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
1
<1
<1
1
1
3
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
—
6.81
6.91
6.95
6.89
6.89
6.89
6.92
6.90
6.92
6.91
6.90
6.91
7.00
7.00
6.99
7.00
7.23
7.00
6.97
7.07
Table 4-3. B. atrophaeus LRVc-TEsx from Individual LRVs
Module Number
Module 1
Module 2
Module 3
Module 4
Module 5
LRVc-TEST
6.81
6.89
6.90
6.99
6.97
4.3 MS-2 Challenge Tests
Table 4-4 presents the MS-2 challenge data. All mean feed counts exceeded the target of IxlO4
PFU/mL. The maximum observed overall mean filtrate count was!40 PFU/mL for Module 2.
The highest individual filtrate count was 212 PFU/mL for the Module 2 3-minute sample.
12
-------
Table 4-4. 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)
—
3.8xl04
4.4xl04
2.9xl04
3.6xl04
—
4.5xl04
6.3xl04
5.6xl04
5.4xl04
—
3.3xl04
4.1xl04
5.0xl04
4.1xl04
—
2.5xl04
3.3xl04
3.7xl04
3.1xl04
—
5.4xl04
5.5xl04
7.4xl04
6.0xl04
Log10
—
4.58
4.64
4.46
4.56
—
4.65
4.80
4.75
4.73
—
4.52
4.61
4.70
4.61
—
4.40
4.52
4.57
4.50
—
4.73
4.74
4.87
4.78
Filtrate
Geometric Mean
(PFU/mL)
<1
19
9
42
19
<1
212
136
95
140
<1
200
127
84
129
<1
103
47
48
61
<1
121
84
64
87
Log10
—
1.28
0.95
1.62
1.25
—
2.33
2.13
1.98
2.14
—
2.30
2.10
1.92
2.10
—
2.01
1.67
1.68
1.78
—
2.08
1.93
1.81
1.94
LRV
—
3.30
3.69
2.84
3.26
2.32
2.67
2.77
2.58
2.22
2.51
2.78
2.49
2.39
2.85
2.89
2.70
2.65
2.81
3.06
2.84
4.3.1 Choosing LRVc-TEsx from the Averages of the Individual LRV Calculations
In Table 4-4, the LRV numbers in the "Overall Mean" rows are the geometric mean calculations
of the individual sample point LRVs for each module. Using this approach, the lowest LRV, and
thus the LRVc-TEsx, is 2.49 for Module 3.
4.3.2 LRVc-TEST 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 4-4 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 4-5.
Under this approach, the LRVs for Modules 1 and 3 differ from the approach in Section 4.3.1.
Module 3 still gives the LRVC.TEST, at 2.50.
13
-------
Table 4-5. 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)
3.6xl04
5.4xl04
4.1xl04
S.lxlO4
6.0xl04
Log10
4.56
4.73
4.61
4.49
4.78
Filtrate
Geometric Mean
(PFU/mL)
19
140
129
61
87
Log10
1.28
2.15
2.11
1.79
1.94
LRV
3.28
2.58
2.50
2.70
2.84
4.3.3 Choosing LRVc-xEsx from the Individual Sample Point LRV Calculations
In Table 4-4, the LRVs for the feed and filtrate pair at each sample point are given in the last
column of the table. The lowest individual LRVs for each module are listed in Table 4-6. Under
this approach, the LRVc-xEsx is 2.22, from Module 3.
Table 4-6. MS-2 LRVC-xEsx from Individual LRVs
Module Number
Module 1
Module 2
Module 3
Module 4
Module 5
IjlvVc-TEST
2.84
2.32
2.22
2.39
2.65
4.4 Operational Data and Water Quality Data for All Challenges
The pilot unit operational data is presented in Table 4-7. The filtrate flow rate recordings ranged
from 22.56 to 23.02 gpm. Note that the flow rate was controlled 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. Siemens' maximum trans-
membrane pressure of 21.7 psig was not exceeded at any time during testing.
The water chemistry data is displayed in Table 4-8. 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 ± 10 mg/L. Two of the pH measurements
were slightly above the maximum target pH of 8.0.
14
-------
Table 4-7. 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.
B. atrophaeus Challenges
Module 1
Module 2
Module 3
Module 4
Module 5
07/24/08
07/25/08
07/28/08
07/29/08
07/30/08
22.89
22.64
22.77
22.71
22.86
23.02
22.87
22.94
22.87
22.96
80.4
79.5
80.0
79.8
80.3
80.9
80.3
80.6
80.3
80.6
36.8
37.9
43.4
35.2
35.2
41.4
39.4
49.0
35.5
35.9
26.6
28.5
33.7
24.7
24.6
30.0
29.6
38.2
24.8
24.9
MS-2 Challenges
Module 1
Module 2
Module 3
Module 4
Module 5
07/24/08
07/25/08
07/28/08
07/29/08
07/30/08
22.62
22.86
22.56
22.96
22.87
22.86
22.86
22.89
22.92
22.94
79.4
80.3
79.2
80.6
80.3
80.3
80.3
80.4
80.5
80.6
39.9
36.4
40.9
35.9
35.1
40.9
39.2
48.3
35.8
35.7
29.1
27.7
31.8
25.2
24.6
29.7
29.6
37.9
25.0
24.8
Table 4-8. Water Chemistry Data
Module #
Date
Alkalinity
(mg/L
CaC03)
PH
Temp. (°C)
Total
Chlorine
(mg/L)
TDS (mg/L)
Turbidity
(NTU)
B. atrophaeus Challenges
Module 1
Module 2
Module 3
Module 4
Module 5
07/24/08
07/25/08
07/28/08
07/29/08
07/30/08
100
100
94
89
88
8.04
7.83
7.79
7.83
7.82
24.3
25.0
23.2
24.9
24.3
O.05
O.05
O.05
O.05
O.05
100
110
110
110
100
0.27
0.15
0.19
0.27
0.20
MS-2 Challenges
Module 1
Module 2
Module 3
Module 4
Module 5
07/24/08
07/25/08
07/28/08
07/29/08
07/30/08
100
98
93
93
91
7.99
8.06
7.84
7.80
7.86
24.1
25.1
23.1
24.9
24.3
O.05
O.05
O.05
O.05
O.05
110
110
110
110
110
0.25
0.24
0.18
0.30
0.26
15
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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
16
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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™ Excel® 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
17
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Accuracy of the benchtop 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%
18
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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, and all
planned operational data readings were collected. This gives a completeness of 100% for all
parameters.
19
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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
20
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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
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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 Membrane Filtration Guidance Manual (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 KH^PC^).
They found that increasing the buffer concentration also increases the EPM toward a positive
B-l
-------
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
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
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4. ETV Test Data Comparing Bacillus endospores and C. parvum
During the Siemens L10V verification test, the membranes were challenged with both B.
atrophaeus and C. parvum so that removal of both organisms could be compared. No C. parvum
was detected in the filtrate samples for any of the five L10V modules tested, but B. atrophaeus
was detected in the filtrate samples for three of the five modules, albeit at less than 1.0 logio per
100 mL. The test data is presented in Tables B-l and B-2.
Table B-l. Siemens L10V C. parvum Challenge Results
Module
Number
Module 1
Module 2
Module 3
Module 4
Module 5
Sample Point
3 Minutes
1 5 Minutes
30 Minutes
Overall Mean
3 Minutes
1 5 Minutes
30 Minutes
Overall Mean
3 Minutes
1 5 Minutes
30 Minutes
Overall Mean
3 Minutes
1 5 Minutes
30 Minutes
Overall Mean
3 Minutes
1 5 Minutes
30 Minutes
Overall Mean
Feed
Geometric Mean
(Oocysts/L)
e.oxio'
7.5xl05
5.7x10'
6.4x10'
3.2xl05
5.8xl05
5.8xl05
4.8x10'
4.8xl05
5.8xl05
4.1xl05
4.9xl05
4.8xl05
4.7x10'
4.7x10'
4.7x10'
5.2x10'
4.7x10'
5.1x10'
5.0x10'
Log™
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
Log™
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
B-3
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Table B-2. Siemens L10V B. atrophaeus Challenge Results
Module 1
Module 2
Module 3
Module 4
Module 5
Sample Point
3 Minutes
1 5 Minutes
30 Minutes
Overall Mean
3 Minutes
1 5 Minutes
30 Minutes
Overall Mean
3 Minutes
1 5 Minutes
30 Minutes
Overall Mean
3 Minutes
1 5 Minutes
30 Minutes
Overall Mean
3 Minutes
1 5 Minutes
30 Minutes
Overall Mean
Feed
Geometric Mean
(CFU/100 mL)
l.OxlO7
9.3xl06
9.0x10°
9.4xl06
6.0xl06
7.5x10"
8.1x10"
7.1x10"
9.9x10"
l.OxlO7
9.6x10"
9.8x10"
l.OSxlO7
6.2x10"
9.7x10"
8.7x10"
6.3x10"
7.4x10"
8.0x10"
7.2x10"
Log™
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)
2
1
4
2
<1
3
<1
1
<1
<1
<1
<1
<1
6
2
2
<1
<1
<1
<1
Logio
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
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-4
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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
—
4.2E+04
4.7E+04
3.1E+04
—
6.9E+04
8.1E+04
5.3E+04
—
2.8E+04
4.7E+04
6.1E+04
—
2.4E+04
4.0E+04
3.0E+04
—
6.3E+04
6.6E+04
6.9E+04
Count 2
—
3.8E+04
5.2E+04
2.6E+04
—
2.9E+04
5.3E+04
5.6E+04
—
4.0E+04
4.0E+04
5.1E+04
—
2.5E+04
2.7E+04
4.8E+04
—
4.4E+04
5.1E+04
7.8E+04
Count 3
—
3.5E+04
3.6E+04
2.9E+04
—
4.6E+04
5.7E+04
6.0E+04
—
3.3E+04
3.7E+04
4.0E+04
—
2.6E+04
3.4E+04
3.5E+04
—
5.8E+04
4.9E+04
7.4E+04
Filtrate (PFU/mL)
Count 1
<1
15
8
39
<1
231
132
80
<1
212
96
73
<1
105
43
38
<1
116
65
52
Count 2
<1
21
5
46
<1
209
129
111
<1
180
120
66
<1
96
34
74
<1
104
79
66
Count 3
<1
21
16
42
<1
197
147
96
<1
210
177
121
<1
109
69
40
<1
148
117
77
Table C-2. B. atrophaeus 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 (CFU/lOOmL)
Count 1
—
6.9E+06
7.6E+06
9.8E+06
—
7.8E+06
6.8E+06
7.6E+06
—
7.4E+06
7.5E+06
7.8E+06
—
1.1E+07
9.4E+06
l.OE+07
—
4.7E+07
9.7E+06
9.8E+06
Count 2
—
6.6E+06
LA
LA
—
9.0E+06
7.1E+06
7.5E+06
—
8.6E+06
8.5E+06
7.1E+06
—
1.1E+07
9.9E+06
9.3E+06
—
9.5E+06
9.5E+06
7.9E+06
Count 3
—
6.1E+06
8.7E+06
8.1E+06
—
6.7E+06
9.3E+06
l.OE+07
—
9.3E+06
8.2E+06
9.0E+06
—
9.5E+06
1.1E+07
9.6E+06
—
l.OE+07
1.1E+07
1.1E+07
Filtrate (CFU/lOOmL)
Count 1
<1
<1
<1
<1
<1
<1
<1
<1
1
<1
<1
1
6
1
1
<1
2
1
1
2
Count 2
<1
<1
<1
<1
<1
<1
<1
<1
1
<1
<1
<1
1
<1
2
1
1
<1
<1
<1
Count 3
<1
<1
<1
<1
<1
<1
<1
<1
1
<1
<1
<1
3
<1
<1
1
<1
<1
<1
<1
C-l
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