THE ENVIRONMENTAL TECHNOLOGY VERIFICATION
PROGRAM
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U.S. Environmental Protection Agency
NSF International
ETV Joint Verification Statement
TECHNOLOGY TYPE: ULTRAFILTRATION
APPLICATION: REMOVAL OF MICROBIAL CONTAMINANTS
PRODUCT NAME: MEMCOR® 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 Memcor® 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
Memcor® 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
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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 ± 10 mg/L as calcium carbonate.
The pH was then lowered with hydrochloric acid to a target range of 7.5 ± 0.5.
NSF 09/30/EPADWCTR
The accompanying notice is an integral part of this verification statement. September 2009
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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
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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
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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
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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
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