September 2004
NSF04/16/EPADWCTR
EPA/600/R-04/186
Environmental Technology
Verification Report
Removal of Arsenic in Drinking Water
Watts Premier
M-Series M-15,000 Reverse
Osmosis Treatment System
Prepared by
NSF International
Under a Cooperative Agreement with
U.S. Environmental Protection Agency
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THE ENVIRONMENTAL TECHNOLOGY VERIFICATION
PROGRAM
ET
>O
v
U.S. Environmental Protection Agency NSF International
ETV Joint Verification Statement
TECHNOLOGY TYPE: MEMBRANE FILTRATION USED IN DRINKING WATER
TREATMENT SYSTEMS
APPLICATION: REMOVAL OF ARSENIC
TECHNOLOGY NAME: WATTS PREMIER M-SERIES M-15,000 REVERSE
OSMOSIS (RO) TREATMENT SYSTEM
COMPANY: WATTS PREMIER
ADDRESS: 1725 W. WILLIAMS DRIVE, #C-20 PHONE: (623)505-1514
PHOENIX, ARIZONA 85027 FAX: (623)931-0191
WEB SITE: www.wattspremier.com
EMAIL: murphysp@wattsind.com
The U.S. Environmental Protection Agency (EPA) supports 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, 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 International (NSF) in cooperation with the EPA operates the Drinking Water Systems (DWS)
Center, one of seven technology areas under the ETV Program. The DWS Center recently evaluated the
performance of a membrane separations system for the reduction of arsenic in drinking water. This
verification statement provides a summary of the test results for the Watts Premier MSeries Ml5,000
Reverse Osmosis (RO) Treatment System. MWH, an NSF-qualified field testing organization (FTO),
performed the verification testing. The verification report contains a comprehensive description of the
test.
04/16/EPADWCTR The accompanying notice is an integral part of this verification statement. September 2004
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ABSTRACT
Verification testing of the Watts Premier M-Series M-15,000 RO Treatment System was conducted over a
31-day period from April 26, 2004, through May 26, 2004. This test was conducted at the Coachella
Valley Water District (CVWD) Well 7802 in Thermal, California. The source water was a chlorinated
groundwater supply. Based on the manufacturer's recommendations, the unit was operated at an average
inlet pressure of 135 pounds per square inch (psi), water recovery of 53%, flux of 34 gallons per square-
foot per day (gfd), and a specific flux of approximately 0.36 gfd/psi at 25 degrees Celsius (°C). The total
arsenic (As) concentration in the feed water averaged 14 micrograms per liter (ug/L) during the testing
period. The M-15,000 RO Treatment System reduced the arsenic levels to below detection (1.0 ug/L) for
all but the last two samples, which were 1.4 and 1.2 ug/L. Six sets of samples were speciated and the
dominant form of arsenic was As(V).
The system operated for 27 days of the 31-day verification period, with three system shut downs due to
operational issues associated with the pre-filter. The verification study indicated that arsenic can be
removed by the M-15,000 RO Treatment System, but depending on the source water characteristics, the
appropriate pre-filter selection is important to prevent clogging of the pre-filters.
TECHNOLOGY DESCRIPTION
The following technology description was provided by the manufacturer and has not been verified.
The M-15,000 RO Treatment System contains six pressure vessels, each containing one 4" x 40"
membrane module. Each stainless steel pressure vessel is four inches (10 cm) in diameter and
approximately 45 inches (110 cm) long. The M-15,000 RO Treatment System is a skid-mounted unit that
is constructed with a carbon steel frame and powder coating. The verification unit is 37 %" (length) x 28
%" (depth) x 53 1A>" (height) and requires a minimum of 18" clearance on all sides for servicing, 40"
clearance on top, and a floor sink drain of 1 1A" diameter within 10' of the processing unit. The main
components of the RO unit are a 3 Hp feed pump, carbon bloc (for removal of chlorine) or sediment pre-
filter pretreatment, six pressure vessels, and an in-line conductivity meter. The M-15,000 RO Treatment
System unit may use either a carbon pretreatment for removal of chlorine or a sediment pre-filter as
standard equipment for the system. The membranes are not tolerant of chlorine and, therefore, when the
system is used on a chlorinated water source, the carbon pretreatment should be used.
VERIFICATION TESTING DESCRIPTION
Test Site
The verification testing site was the CVWD Well 7802 located in Thermal, California. The feed water for
the verification study was a chlorinated source, with an average free chlorine residual of 0.47 milligrams
per liter (mg/L). The chlorine enters the distribution system at the discharge manifold, and was fed from
a Hammond's tablet feeder using calcium hypochlorite tablets as the chlorine source. The average feed
water quality during the verification testing is provided in the table below.
In addition to being a suitable fit for water quality, the site also had sufficient access (1 acre site); full
electrical supply with backup diesel powered generator; 6' privacy/security wall; all utilities readily
available including raw water supply, power, and a drain (blow-off structure) for the discharge of the
water from the ETV verification testing; and safety facilities, including an emergency shower and
eyewash.
04/16/EPADWCTR The accompanying notice is an integral part of this verification statement. September 2004
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Total Arsenic
Dissolved Arsenic
As (III)
As(V)1
TOC
Calcium
Chloride
Hardness
Alkalinity
Free Chlorine
Total Chlorine
pH2
Temperature
Mg/L
Mg/L
Mg/L
Mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
--
°C
27
5
5
5
5
5
5
5
5
18
18
27
54
14
14
3.7
11
<0.50
4.8
8.5
18
83
0.47
0.51
9.213
27.5
Turbidity
Conductivity
TDS
TSS
Manganese
Iron
Barium
Silica
Fluoride
Sulfate
Chromium
Vanadium
NTU3
umoh/cm
mg/L
mg/L
Mg/L
mg/L
Mg/L
mg/L
mg/L
mg/L
Mg/L
Mg/L
5
54
27
5
5
5
5
5
5
5
5
5
0.40
231
140
<10
<2.0
0.019
7.1
15
0.80
20
13
49
Average Feed Water Quality during Verification Testing
#of
Parameter Units Samples Average Parameter
Units
#of
Samples
Average
1 As (V) is a calculated value.
3 pH is reported as the median, not the average.
3 Nephelometric Turbidity Unit(s).
Methods and Procedures
Water quality was monitored from three water streams: feed water, permeate, and concentrate.
Conductivity, pH, turbidity, chlorine (free and total), temperature, alkalinity, hardness analyses were
conducted on-site, using equipment set up in the pump house at CVWD Well 7802 and in accordance
with Standard Methods for the Examination of Water and Wastewater, 2Cfh edition. Conductivity and
feed water temperature were monitored twice per day, while pH was monitored once per day. Alkalinity,
hardness, chlorine, and turbidity were monitored once per week on-site using methods approved by NSF.
The following additional samples were sent to MWH Laboratories for analysis: arsenic (total, dissolved,
and As+3), total suspended solids (TSS), total dissolved solids (TDS), total organic carbon (TOC), silica,
barium, calcium, chloride, sulfate, iron, manganese, fluoride, chromium, and vanadium. Total arsenic
and TDS samples were collected once per day; dissolved arsenic, As+3, TSS, TDS, TOC, silica, barium,
calcium, chloride, sulfate, iron, manganese, fluoride, chromium, and vanadium samples were collected
once per week. One sample was collected during the verification test for silt density index (SDI) analysis.
Complete descriptions of the verification testing results and quality assurance/quality control procedures
are included in the verification report.
VERIFICATION OF PERFORMANCE
System Operation
RO is a pressure-driven process, with the pressure used for separation by allowing fresh water to move
through a membrane, leaving various dissolved constituents of the water behind. In the M-l5,000 RO
Treatment System, feed water is initially passed through a pre-filter (sediment filter or carbon bloc for
chlorine removal) to remove particles that have the potential to damage the membrane. There is a
sampling port just prior to the pre-filter to collect the feed water samples. After passing through the pre-
filter, the feed water is blended with re-circulated concentrate water and is then referred to as the inlet
water. The inlet water is then sent through a booster pump and after leaving the discharge side of the
pump, the water line is split and feeds the two separate banks of membranes (six membranes in total),
starting with membrane 1 and 4. For the first bank of membranes, concentrate from membrane 1 feeds
membrane 2 and concentrate from membrane 2 feeds membrane 3. For the second bank of membranes,
concentrate from membrane 4 feeds membrane 5 and concentrate from membrane 5 feeds membrane 6.
04/16/EPADWCTR
The accompanying notice is an integral part of this verification statement.
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September 2004
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Permeate from all membranes is collected from the bottom of the housing and exits the unit as drinking
water. There is a permeate sample port for each of the six membranes, as well as the blended permeate
from all six of the membranes. During the verification test, permeate samples were collected from the
blended permeate sample port. Concentrate from membranes 3 and 6 is split, some being purged to waste
and some re-circulating back to the head of the system, just after the pre-filter where it is blended with the
feed water to create the inlet water. The concentrate that is re-circulated back to the head of the system is
referred to as recycle water.
The M-15,000 RO Treatment System was set up in accordance with the manufacturer's recommendations
the week prior to the verification test. The unit was tested to make sure all systems were operating in
accordance with their recommended ranges. Based on discussions between the FTO and the
manufacturer, the set points were adjusted to achieve a 50% permeate recovery. Once the set points were
adjusted, the system flow rates were stable for the remainder of the verification period. The feed water
pressure was stable throughout the testing period, however, the inlet pressure varied from 102 to 145 psi,
due to clogging of the carbon bloc pre-filter. Once the pre-filter was replaced with a sediment filter, the
inlet pressures stabilized (140 to 150 psi) for the remainder of the verification testing.
Water Quality Results
The M-15,000 RO Treatment System removed the feed water total arsenic from 14 ug/L (on average) to
non-detectable levels (<1.0 ug/L) for all but the last two samples collected, which were 1.4 and 1.2 ug/L.
As shown in the figure below, the unit was able to produce a consistent, high quality permeate with total
arsenic levels below 1.0 ug/L in 95% of the samples over the range of feed water of 12 to 16 ug/L.
Throughout most of the verification test, the total arsenic mass balance was very close, with the exception
of April 29, 2004, and May 10, 2004, where the arsenic concentration in the concentrate stream was
significantly higher (greater than the 95% confidence interval), at 84 ug/L and 38 ug/L respectively. The
permeate conductivity and TDS slowly increased throughout the verification testing, starting around 6.4
umoh/cm and increasing to 76.6 umoh/cm for conductivity and starting at <10 mg/L and increasing to 45
mg/L for TDS. During the verification testing, a total of five weekly samples were collected for inorganic
analyses. Based on these five samples, the M-15,000 RO Treatment System removed on average: >72%
barium, >79% calcium, 85% fluoride, 85% chloride, >92% chromium, >90% sulfate, >93% vanadium,
38% iron, and 62% silica. Manganese was also sampled and analyzed during the verification testing, but
the percent removal could not be determined due to non-detectable (<2 ug/L) levels for all of the feed
water and permeate samples.
04/16/EPADWCTR The accompanying notice is an integral part of this verification statement. September 2004
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-n Concentrate
Feed Water
-O Permeate
Verificatin Testing Date
Temporal Plot of Total Arsenic
Operation and Maintenance Results
The system ran continuously for 27 of the 31-day verification testing period. For one 4-day period, the
system was shut down due to operational issues. Clogging of the carbon bloc pre-filter is believed to be
the cause of the shut down. The unit automatically shut down on two separate occasions, also believed to
be related to clogging of the carbon bloc pre-filter. On May 13, 2004 the carbon bloc pre-filter was
replaced with a 20-micron sediment pre-filter. The system ran continuously after the sediment filter was
installed, until the end of the verification testing on May 26, 2004, when the system was manually shut
down.
Quarterly maintenance was conducted upon completion of the verification testing. The maintenance
procedure took approximately 45 minutes to change out the O-rings on the pre-filter and brine line, and
replace the pre-filter and two of the six RO membranes. Upon completion of the maintenance procedures,
the system was started back up and both water quality and operational conditions were recorded. The
specific flux immediately prior to the maintenance was 0.34 gfd/psi and upon start up after the
maintenance was 0.33 gfd/psi, thus a 97% recovery of specific flux was achieved upon completion of the
maintenance procedures.
04/16/EPADWCTR
The accompanying notice is an integral part of this verification statement.
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September 2004
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Consumables and Waste Generation
There were no "consumable" chemical items used for the verification testing; however, the pre-filter to
the system would be a consumable product and would have to be disposed of as solid waste. The
concentrate waste stream produced from the verification test was blended back with the permeate water
for an equivalent water quality to the feed water from the CVWD Well 7802. This water was then sent to
a blow-off structure for disposal. The estimated concentrate production rate was 17,300 gallons per day,
based on the targeted 50% permeate recovery.
Quality Assurance/Quality Control
NSF provided technical and quality assurance oversight of the verification testing as described in the
verification report, including an audit of nearly 100% of the data. NSF 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
Lawrence W. Reiter
09/30/04
Original Signed by
Gordon Bellen
09/30/04
Lawrence W. Reiter Date
Acting Director
National Risk Management Research Laboratory
Office of Research and Development
United States Environmental Protection Agency
Gordon Bellen
Vice President
Research
NSF International
Date
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 ETV Protocol for Equipment Verification Testing for Arsenic Removal
dated September 2003, the ETV Protocol for Equipment Verification Testing for Removal
of Inorganic Constituents dated April 2002, the verification statement, and the
verification report (NSF Report # 04/16/EPADWCTR) are available from the following
sources:
(NOTE: Appendices are not included in the verification report. Appendices are available
from NSF upon request.)
1. ETV Drinking Water Systems Center Manager (order hard copy)
NSF International
P.O. Box 130140
Ann Arbor, Michigan 48113-0140
2. NSF web site: http://www.nsf. org/etv (electronic copy)
3. EPA web site: http://www. epa.gov/etv (electronic copy)
04/16/EPADWCTR
The accompanying notice is an integral part of this verification statement. September 2004
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September 2004
Environmental Technology Verification Report
Removal of Arsenic in Drinking Water
Watts Premier M-Series
M-15,000 Reverse Osmosis Treatment System
Prepared for:
NSF International
Ann Arbor, Michigan 48105
Prepared by:
MWH
Pasadena, CA 91101
Under a cooperative agreement with the U.S. Environmental Protection Agency
Jeffrey Q. Adams, Project Officer
National Risk Management Research Laboratory
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
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Notice
The U.S. Environmental Protection Agency (EPA), through its Office of Research and
Development, has financially supported and collaborated with NSF International (NSF) under
Cooperative Agreement No. R-82833301. This verification effort was supported by the Drinking
Water Systems (DWS) Center, operating under the Environmental Technology Verification
(ETV) Program. This document has been peer reviewed, reviewed by NSF and EPA, and
recommended for public release.
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Foreword
The U.S. Environmental Protection Agency (EPA) is charged by Congress with
protecting the Nation's land, air, and water resources. Under a mandate of national
environmental laws, the Agency strives to formulate and implement actions leading to a
compatible balance between human activities and the ability of natural systems to support and
nurture life. To meet this mandate, EPA's research program is providing data and technical
support for solving environmental problems today and building a science knowledge base
necessary to manage our ecological resources wisely, understand how pollutants affect our
health, and prevent or reduce environmental risks in the future.
The National Risk Management Research Laboratory (NRMRL) is the Agency's center
for investigation of technological and management approaches for preventing and reducing risks
from pollution that threaten human health and the environment. The focus of the Laboratory's
research program is on methods and their cost-effectiveness for prevention and control of
pollution to air, land, water, and subsurface resources; protection of water quality in public water
systems; remediation of contaminated sites, sediments and ground water; prevention and control
of indoor air pollution; and restoration of ecosystems. NRMRL collaborates with both public
and private sector partners to foster technologies that reduce the cost of compliance and to
anticipate emerging problems. NRMRL's research provides solutions to environmental problems
by: developing and promoting technologies that protect and improve the environment; advancing
scientific and engineering information to support regulatory and policy decisions; and providing
the technical support and information transfer to ensure implementation of environmental
regulations and strategies at the national, state, and community levels.
This publication has been produced as part of the Laboratory's strategic long-term
research plan. It is published and made available by EPA's Office of Research and Development
to assist the user community and to link researchers with their clients.
Lawrence W. Reiter, Acting Director
National Risk Management Research Laboratory
in
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Table of Contents
Section Page
Verification Statement VS-i
Title Page i
Notice ii
Foreword iii
Table of Contents iv
Abbreviations and Acronyms ix
Acknowledgements x
Chapter 1 Introduction 1
1.1 ETV Purpose and Program Operation 1
1.2 Testing Participants and Responsibilities 1
1.2.1 NSF International 2
1.2.2 Field Testing Organization 2
1.2.3 Manufacturer 3
1.2.4 Analytical Laboratory 3
1.2.5 U.S. Environmental Protection Agency 4
1.3 Verification Testing Site 4
1.3.1 Source Water 4
1.3.2 Pilot Effluent Discharge 5
1.3.3 Discharge Permits 5
Chapter 2 Equipment Description and Operating Processes 6
2.1 Equipment Description 6
2.2 Operating Process 10
Chapter 3 Methods and Procedures 13
3.1 Quantitative and Qualitative Evaluation Criteria 13
3.2 Key Treated Water Quality Parameters 13
3.2.1 Key Groundwater Quality Parameters the Equipment is Designed to Address 13
3.2.2 Key Treated Water Quality Parameters for Evaluating Equipment Performance ...14
3.3 Calculations 14
3.3.1 Calculation of Statistical Uncertainty 14
3.3.2 Calculation and Definition of Operational Parameters 15
3.4 Testing Schedule 19
3.5 Operation and Maintenance 20
3.6 Field Operations Procedures 20
3.7 Environmental Technology Verification Testing Plan 20
3.7.1 Task 1: Membrane Operation 21
3.7.2 Task 2: Cleaning Efficiency 21
3.7.3 Task 3: Feed Water and Treated Water Quality Monitoring 21
3.7.4 Task 4: Data Handling Protocol 22
3.7.5 Task 5: Quality Assurance Project Plan (QAPP) 22
3.8 Task 1: Membrane Optimization 22
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Table of Contents (continued)
Section Page
3.8.1 Experimental Objectives 23
3.8.2 Work Plan 23
3.8.3 Analytical Schedule 24
3.8.4 Evaluation Criteria and Minimum Reporting Criteria 24
3.9 Task 2: Cleaning Efficiency 25
3.9.1 Experimental Objectives 25
3.9.2 Work Plan 25
3.9.3 Analytical Schedule 26
3.9.4 Evaluation Criteria and Minimum Reporting Criteria 26
3.10 Task 3: Water Quality Monitoring 27
3.10.1 Experimental Objectives 27
3.10.2 Work Plan 28
3.10.3 Analytical Schedule 28
3.10.4 Evaluation Criteria And Minimum Reporting Criteria 29
3.11 Task 4: Data Handling Protocol 29
3.11.1 Experimental Objectives 30
3.11.2 Work Plan 30
3.12 Task 5: Quality Assurance Project Plan (QAPP) 31
3.12.1 Experimental Objectives 31
3.12.2 Work Plan 31
3.12.3 Monthly QA/QC Verification 31
3.12.4 Data Correctness 31
3.12.4.1 Representativeness 32
3.12.4.2 Statistical Uncertainty 36
3.12.4.3 Methodology for Measurement of Precision and Accuracy 37
3.12.4.4 Completeness 41
3.12.5 Calculation of Indictors of Data Quality 41
3.12.6 Corrective Action Plan 42
3.13 Operation And Maintenance 43
3.13.1 Operation 43
3.13.2 Maintenance 44
3.13.3 Operability 45
Chapter 4 Results and Discussion 46
4.1 Introduction 46
4.2 Task 1: Membrane Operation 46
4.2.1 General Operational Performance 41
4.2.1.1 Feed Water, Permeate, Concentrate, and Recycle Flow Rates 47
4.2.1.2 Membrane Element Inlet and Feed Water Pressures 50
4.2.1.3 Water Recovery and Recycle Ratio 53
4.2.1.4 Feed Water Temperature 55
4.2.1.5 Flux, Specific Flux, Net Driving Pressure, and Osmotic Pressure 56
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Table of Contents (continued)
Section Page
4.2.2 Power Consumption 62
4.2.3 Consumables and Waste Generation 63
4.3 Task 2: Cleaning Efficiency 63
4.3.1 Measurement of Membrane Performance - Post Quarterly O&M Procedures 65
4.3.2 Review of Watts Premier Operation and Maintenance Manual 67
4.4 Task 3: Feed Water And Treated Water Quality Monitoring 67
4.4.1 Percent Removal Of Inorganic Chemical Constituents 75
4.4.2 Percent Removal Of Organic Constituents 80
4.4.2.1 Mass Balance for Total Arsenic 81
4.4.2.2 Limiting Salt Concentrations 82
4.4.3 Removal of TSS 83
4.4.4 SDI 84
4.4.5 LSI 84
4.5 Task 4: Data Handling Protocol 83
4.6 Task 5: Quality Assurance/Quality Control Results 83
4.6.1 Precision 83
4.6.2 Accuracy 88
4.6.3 Off-Site Analysis of Samples 90
4.6.3.1 Inorganic Samples 95
4.6.3.2 Organic Samples 95
4.6.4 Completeness 90
4.6.5 NSF Field Inspection 90
Chapter 5 References 97
Chapter 6 Vendor Comments 98
Table
Table 1-1: Average Feed Water Quality during Verification Testing 4
Table 2-1: Membrane Plant Design Criteria Reporting Items 9
Table 2-2: Membrane Element Characteristics 9
Table 2-3: Watts Premier M-l 5,000 RO Treatment System Specifications 11
Table 3-1: Quantitative and Qualitative Evaluation Criteria 13
Table 3-2: Operating Range of Watts Premier RO Membrane 14
Table 3-3: Key Treated Water Quality Parameters 14
Table 3-4: Equipment Operational Characteristics to be Evaluated in Each Task 22
Table 3-5: Frequency and Type of Operating Data 24
Table 3-6: Sampling Schedule and Methods for Feed, Permeate, & Concentrate Water 27
Table 3-7: Methodology for Measurement of Precision and Accuracy 37
Table 3-8: Laboratory Water Quality Indicators 39
Table 3-9: On-Site Water Quality Analysis Indicators 40
Table 3-10: Methodology for Use of Method Blanks 40
Table 3-11: Completeness Objectives Based on Sample Frequency 41
VI
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Table of Contents (continued)
Table
Page
Table 3-12: Corrective Action Plan [[[ 43
Table 4-1: Feed Water, Permeate, Concentrate and Recycle Flow Rates ..................................... 49
Table 4-2: Feed Water, Inlet, Back Pressure, and Tank Pressures ............................................... 52
Table 4-3: Water Recovery and Recycle Ratio [[[ 54
Table 4-4: Feed Water Temperature [[[ 55
Table 4-5: Daily Flux Data [[[ 57
Table 4-6: Daily Specific Flux Data at 25°C [[[ 58
Table 4-7: Osmotic Pressure Gradient [[[ 60
Table 4-8: Net Driving Pressure [[[ 62
Table 4-9: Power Totalizer for M-l 5,000 RO Treatment System ................................................ 63
Table 4-10: Pre-and Post-Maintenance Specific Flux Recoveries ............................................... 66
Table 4-11: Maintenance Efficiency Indicators [[[ 66
Table 4-12: Pre and Post O&M Feed Water, Permeate, and Concentrate Water Quality ............ 67
Table 4-13: Daily Feed Water, Concentrate, Permeate, and Total Arsenic Data ......................... 69
Table 4-14: Daily Feed Water, Concentrate, Permeate, and TDS ................................................ 71
Table 4- 15 Daily pH Analysis [[[ 72
Table 4-16: Daily Conductivity Analysis [[[ 73
Table 4-17: On-site Weekly Water Quality Monitoring [[[ 74
Table 4-18: On-site Free and Total Chlorine Monitoring [[[ 75
Table 4-19: Weekly Speciated Arsenic Analyses [[[ 76
Table 4-20: Weekly Analytical Parameters and Percent Removal ............................................... 77
Table 4-21: Percent Removal of Organic Constituents [[[ 80
Table 4-22: Daily Total Arsenic Mass Balance [[[ 82
Table 4-23: Solubility Products of Limiting Salt Concentrations ................................................ 83
Table 4-24: Removal of Total Suspended Solids [[[ 84
Table4-25: LSI Calculations (April 26, 2004) [[[ 85
Table 4-26: Weekly Off-site Analytical Precision [[[ 87
Table 4-27: On-site Analytical Precision [[[ 88
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Table of Contents (continued)
Figure Page
Figure 4-4: Temporal plot of flux verses time 56
Figure 4-5: Specific flux at 25°C verses time 58
Figure 4-6: Osmotic pressure gradient verses time 59
Figure 4-7: Temporal profile of net driving pressure 61
Figure 4-8: Temporal plot of total arsenic 68
Figure 4-9: Temporal plot of TDS 70
Figure 4-10: Temporal plot of silica 78
Figure 4-11: Temporal plot of fluoride 78
Figure 4-12: Temporal plot of iron 79
Figure 4-13: Temporal plot of chloride 79
Figure 4-14: Temporal plot of sulfate 80
Figure 4-15: Daily total arsenic mass balance 81
Photograph Page
Photograph 1: Permeate and Concentrate Discharge Lines 5
Photograph 2: Watts Premier M-15,000 RO Treatment System at CVWD Well 7802 8
Photograph 3: Pre-Filter to Watts Premier M-15,000 RO Treatment System 10
Photograph 4: Watts Premier M-15,000 RO Treatment System Pre-filters 64
Photograph 5: Membrane RO Number 6 - Post Verification Testing 65
Appendices
Appendix A: Watts Premier M-Series M-15,000 RO Treatment System O&M Manual
Appendix B: On-Site Arsenic Speciation Procedures
Appendix C: On-Site Logbook
Appendix D: Analytical Data from MWH Laboratories
Appendix E: Analytical Data and Procedures from SDI Analysis
Vlll
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Abbreviations and Acronyms
AM morning
As arsenic
As (III) arsenite
As (V) arsenate
ASTM American Society of Testing and Materials
°C degree Celsius
CVWD Coachella Valley Water District
°F degree Fahrenheit
EPA Environmental Protection Agency
ETV environmental technology verification
Ft feet
FTO field testing organization
gfd gallons per square-foot per day
gfd/psi gallons per square-foot per day per pounds per square inch
gpd gallons per day
gpm gallon per minute
LCS laboratory control sample
LFM laboratory fortified matrix
LSI Langelier Saturation Index
MB method blank
mL milliliter
mg/L milligram
MRL minimum reporting limit
NDP net driving pressure
NELAC National Environmental Laboratory Accreditation Conference
NIST National Institute of Standards and Technology
NRMRL National Risk Management Research Laboratory
NSF NSF International (formerly known as the National Sanitation Foundation)
NTU nephelometric turbidity unit(s)
O&M operation and maintenance
p pressure
PM evening
psi pounds per square inch
psig gauge pressure
PSTP Product Specific Test Plan
Q flow rate
QAPP Quality Assurance Project Plan
RO reverse osmosis
RPD Relative percent difference
SDI silt density index
T temperature
TDS total dissolved solids
TOC total organic carbon
TSS total suspended solids
ug microgram
IX
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Acknowledgments
The field testing organization (FTO), MWH, was responsible for all elements in the testing
sequence, including collection of samples, calibration and verification of instruments, data
collection and analysis, data management, data interpretation, and the preparation of this report.
MWH
300 N. Lake Ave, Suite 1200
Pasadena, California 91101
Contact Person: Thomas Gillogly, Ph.D.
The laboratory selected for analytical work for this study was:
MWH Laboratories
750 Royal Oaks Lane, Suite 100
Monrovia, California 91016
Contact Person: Andrew Eaton, Ph.D.
The manufacturer of the equipment was:
Watts Premier
1725 W. Williams Drive, #C-20
Phoenix, Arizona 85027
Contact Person: Shannon Murphy
MWH wishes to thank NSF International (NSF), especially Mr. Bruce Bartley, Project Manager,
and Mrs. Angela Beach, Project Coordinator, for providing guidance and program management.
MWH also wishes to thank the Coachella Valley Water District (CVWD) for providing the site
for verification testing including providing assistance in connecting to the water system and all
necessary utilities (water, sewer, and electrical).
NSF wishes to thank Mr. Dale Scherger, Environmental Consultant, Scherger Associates, for
providing technical guidance.
Mr. Shannon Murphy and Mr. Adam Nelson, Watts Premier, are to be commended for providing
the treatment system and the excellent technical and product expertise.
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Chapter 1
Introduction
1.1 ETV Purpose And Program Operation
The U.S. Environmental Protection Agency (EPA) has created the Environmental Technology
Verification (ETV) Program to facilitate the deployment of innovative or improved
environmental technologies through performance verification and dissemination of information.
The goal of the ETV Program is to further environmental protection by accelerating the
acceptance and use of improved and more cost-effective technologies. ETV seeks to achieve this
goal by providing high-quality, peer-reviewed data on technology performance to those involved
in the design, distribution, permitting, purchase, and use of environmental technologies.
ETV works in partnership with recognized standards and testing organizations; with stakeholder
groups consisting of buyers, vendor organizations, and permitters; and with the full participation
of individual technology developers. The program evaluates the performance of innovative
technologies by developing test plans responsive to the needs of stakeholders, conducting field
demonstrations, 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.
The EPA has partnered with NSF International (NSF) under the ETV Drinking Water Systems
(DWS) Center to verify the performance of small drinking water systems that serve small
communities. A goal of verification testing is to enhance and facilitate the acceptance of small
drinking water treatment equipment by state drinking water regulatory officials and consulting
engineers, while reducing the need for testing of equipment at each location where the
equipment's use is contemplated. NSF meets this goal by working with manufacturers and NSF-
qualified Field Testing Organizations (FTOs) to conduct verification testing under the approved
protocols. It is important to note that verification of the equipment does not mean the equipment
is "certified" by NSF or "accepted" by EPA. Rather, it recognizes that the performance of the
equipment has been determined and verified by these organizations for those conditions tested by
the FTO.
The ETV DWS Center evaluated the performance of the Watts Premier M-Series M-15,000
Reverse Osmosis (RO) Treatment System, which is a membrane technology used in drinking
water treatment system applications. The verification test evaluated the ability of the RO system
to remove arsenic from drinking water under specific feed water quality and conditions. This
document provides the verification test results for the M-15,000 RO Treatment System.
1.2 Testing Participants And Responsibilities
The ETV testing of the M-15,000 RO Treatment System was a cooperative effort among the
following participants:
NSF International
MWH
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Watts Premier
MWH Laboratories
U.S. Environmental Protection Agency
The following is a brief description of all of the ETV participants and their roles and
responsibilities.
1.2.1 NSF International
NSF is an independent, not-for-profit testing and certification organization dedicated to public
health and safety and to the protection of the environment. Founded in 1946 and located in Ann
Arbor, Michigan, NSF has been instrumental in the development of consensus standards for the
protection of public health and the environment. NSF also provides testing and certification
services to ensure products bearing the NSF Name, Logo and/or Mark meet those standards. The
EPA partnered with NSF to verify the performance of drinking water treatment systems through
the EPA's ETV Program.
NSF provided technical oversight of the verification testing and conducted an audit of the field
analytical data gathering and recording procedures. NSF also provided review of the Product
Specific Test Plan (PSTP) as well as this report.
Contact Information:
NSF International
789 N. Dixboro Road
Ann Arbor, MI 48105
Phone: (734) 769-8010
Fax: (734)769-0109
Contact: Bruce Bartley, Project Manager
Email: bartley@nsf.org
1.2.2 Field Testing Organization
MWH, an environmental engineering consulting firm, conducted the verification testing of the
M-15,000 RO Treatment System. MWH is an NSF-qualified FTO for the ETV DWS Center.
The FTO was responsible for conducting the verification testing for 31 calendar days. The FTO
provided all needed logistical support, established a communications network, and scheduled and
coordinated activities of all participants. The FTO was responsible for ensuring the testing
location and feed water conditions were such that the verification testing could meet its stated
objectives. The FTO prepared the PSTP; oversaw the pilot testing; managed, evaluated,
interpreted, and reported on the data generated by the testing; and evaluated and reported on the
performance of the technology.
FTO employees conducted the on-site analyses and data recording during the testing. The FTO's
project engineer and project manager provided oversight of the daily tests.
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Contact Information:
MWH
300 N. Lake Avenue, Suite 1200
Pasadena, CA 91101
Phone: (626) 568-6010
Fax: (626) 568-6015
Contact Person: Thomas Gillogly, Ph.D
Email: Thomas.Gillogly@MWHGlobal.com
1.2.3 Manufacturer
The treatment system is manufactured by Watts Premier, a water treatment equipment
manufacturer and supplier. The manufacturer was responsible for supplying a field-ready M-
15,000 RO Treatment System equipped with all necessary components, including treatment
equipment, instrumentation and controls and an operation and maintenance (O&M) manual. The
manufacturer was responsible for providing logistical and technical support, as needed, as well
as technical assistance to the FTO during operation and monitoring of the equipment undergoing
field verification testing.
Contact Information:
Watts Premier
1725 W. Williams Drive, #C-20
Phoenix, Arizona 85027
Phone: (623)505-1514
Fax: (623)931-0191
Contact Person: Shannon Murphy
Email: murphysp@wattsind.com
1.2.4 A nalytical Laboratory
The specific responsibilities of the water quality analytical staff, MWH Laboratory, were to
provide all off-site water quality analyses prescribed in the PSTP according to the Quality
Assurance/Quality Control (QA/QC) and the protocols contained therein, provide reports with
the analytical results to the data manager, and provide detailed information on the analytical
procedures implemented.
Contact Information:
MWH Laboratories
750 Royal Oaks, Suite 100
Monrovia, CA 91016
Phone: (626)386-1100
Fax: (626)386-1101
Contact Person: Andrew Eaton, Ph.D.
Email: Andrew.Eaton@MWHGlobal.com
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1.2.5 U.S. Environmental Protection Agency
The EPA, through its Office of Research and Development, has financially supported and
collaborated with NSF under Cooperative Agreement No. R-82833301. This verification effort
was supported by the DWS Center operating under the ETV Program. This document has been
peer reviewed, reviewed by NSF and EPA, and recommended for public release.
1.3 Verification Testing Site
The test site selected for the verification testing of the M-15,000 RO Treatment System was the
Coachella Valley Water District's (CVWD) Well 7802 located in Thermal, California. The
following sections provide additional information on the test site (source water characteristics
and discharge method).
1.3.1 Source Water
The feed water used during the verification study was a chlorinated source, with an average free
chlorine residual of 0.47 milligrams per liter (mg/L). The chlorine enters the distribution system
at the discharge manifold, and was fed from a Hammond's tablet feeder using calcium
hypochlorite tablets as the chlorine source. A summary of the average feed water quality values
from the 27 days of operation during the verification testing is presented in Table 1-1. Complete
descriptions of the verification testing results and quality assurance/quality control procedures
are included in Chapters 3 and 4.
Table 1-1: Average Feed Water Quality during Verification Testing
Parameter
Total Arsenic
Dissolved Arsenic
Arsenite (As (III))
Arsenate (As(V))1
Total Organic
Carbon (TOC)
Calcium
Chloride
Hardness
Alkalinity
Free Chlorine
Total Chlorine
pH2
Temperature
Number of
Units Samples
Mg/L
Mg/L
Mg/L
Mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
--
°C
27
5
5
5
5
5
5
5
5
18
18
27
54
Average
14
14
3.7
11
<0.50
4.8
8.5
18
83
0.47
0.51
9.21
27.5
Parameter
Turbidity
Conductivity
Total Dissolved
Solids (TDS)
Total Suspended
Solids (TSS)
Manganese
Iron
Barium
Silica
Fluoride
Sulfate
Chromium
Vanadium
Number of
Units Samples
NTU3
umoh/cm
mg/L
mg/L
Mg/L
mg/L
Mg/L
mg/L
mg/L
mg/L
Mg/L
Mg/L
5
24
27
5
5
5
5
5
5
5
5
5
Average
0.40
231
140
<10
<2.0
0.019
7.1
15
0.80
20
13
49
As (V) is a calculated value.
pH is reported as the median, not the average.
Nephelometric Turbidity Unit(s).
-------
1.3.2 Pilot Effluent Discharge
All treated water (RO permeate) and waste (RO concentrate) were blended back together and
sent to a blow-off drain for disposal, see clear 1-inch flexible tubing in Photograph 1. The
blended water produced from the equipment being tested was not anticipated to adversely impact
the environment, as the quality of the blended water was equivalent to the well's raw water
quality, with the exception of chlorine. The blow-off drain had sufficient capacity to accept the
blended water (treated and concentrate) flow rate for the duration of the study. De-chlorination
tablets were added to the drain where the water from the verification unit was discharging.
Permeate and concentrate
discharge lines
Photograph 1: Permeate and Concentrate Discharge Lines
1.3.3 Discharge Permits
No discharge permits were necessary for this verification study.
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Chapter 2
Equipment Description and Operating Processes
2.1 Equipment Description
The equipment tested in the ETV was the M-15,000 RO Treatment System. The M-15,000 RO
Treatment System verification unit contains six pressure vessels, each containing one 4" x 40"
membrane module. Each stainless steel pressure vessel is 4 inches (10 cm) in diameter and
approximately 45 inches (110 cm) long. A schematic of the system is shown in Figure 2-1 and a
photograph of the unit is shown in Photograph 2, which specifically shows the panel mounted
flow meters, pressure gauges, recirculation needle valve, and individual membrane sample ports.
531/2
-283/4-
fl5P
n
V230VAC/15A
,,-Water Supply Utility Connection (cold = 1" NPT)
/ ,-Permeate Connection (1" NPT)
/
oncentrate / Drain (1.25" NPT minimum)
Figure 2-1: Watts Premier M-Series M-15,000 RO Treatment System.
The feed water is initially passed through a pre-filter (sediment filter or carbon bloc for chlorine
removal) to remove particles that have the potential to damage the membrane. There is a
sampling port just prior to the pre-filter to collect the feed water samples. After passing through
the pre-filter, the feed water is blended with re-circulated concentrate water and is then referred
to as the inlet water. The inlet water is then sent through a booster pump and after leaving the
discharge side of the pump, the water line is split and feeds the two separate banks of membranes
-------
(three membranes per bank, six membranes in total), starting with membrane 1 and 4. For the
first bank of membranes, concentrate from membrane 1 feeds membrane 2 and concentrate from
membrane 2 feeds membrane 3. For the second bank of membranes, concentrate from
membrane 4 feeds membrane 5 and concentrate from membrane 5 feeds membrane 6. Permeate
from all membranes is collected from the bottom of the housing and exits the unit as drinking
water. There is a permeate sample port for each of the six membranes, as well as the blended
permeate from all six of the membranes. During the verification test, permeate samples were
collected from the blended permeate sample port. Concentrate from membranes 3 and 6 is split,
some being purged to waste and some re-circulating back to the head of the system, just after the
pre-filter where it is blended with the feed water to create the inlet water. The concentrate that is
re-circulated back to the head of the system is referred to as recycle water. A process flow
diagram of the flow streams through the M-15,000 RO Treatment System is presented in Figure
2-2.
Figure 2-2: Watts Premier M-15,000 RO Treatment System process flow diagram and
sample locations.
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Photograph 2: Watts Premier M-15,000 RO Treatment System at CVWD Well 7802
The recycle rate was determined during the initial shake down period, but was expected to be
75% at 130 to 150 pounds per square inch (psi) (based on the manufacturer's experience) and
was manually adjusted through a recirculation needle control valve. For a standard M-15,000
RO Treatment System, recycle ratio is not a measured operational parameter. For the verification
study, the recycle flow rate was monitored through a flow meter (not a standard part) located on
the recycle water line in order to calculate the recycle ratio and determine the tne osmotic
gradient across the membranes.
The qualitative, quantitative and cost factors of the tested equipment were identified, in so far as
possible, during the verification testing. The relatively short duration of the study created
difficulty in reliably identifying some of these factors. The qualitative factors examined during
the verification were operational aspects of the M-15,000 RO Treatment System; for example,
susceptibility to changes in environmental conditions, operational requirements and equipment
safety, as well as other factors that might impact performance. The quantitative factors
examined during the verification testing process were costs associated with the system, such as
power, filter cartridge replacement, cost of operation and disposal costs. The operating
conditions were recorded in the project logbook. Specific information regarding the membrane
plant design criteria and membrane element characteristics may be found on Table 2-1 and Table
2-2.
8
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Table 2-1: Membrane Plant Design Criteria Reporting Items
Parameter
Value
Number of Stages
Number of Pressure Vessels in Stage 1
Number of Pressure Vessels in Stage 2
Number of Membrane Elements per Pressure Vessel
Recovery per Stage (%)
Recovery for System
Design Flux
Pressure Loss per Element
Pressure Loss in Stage Entrance and Exit
Feed Stream IDS (mg/L)
IDS rejection
Rejection of Specific Inorganic Constituents
2
1
6
1
NA1
50%
12gfd2
6 psi
ISOpsi
Based on Influent Water Quality
95-99%
80-99%
1 NA = Not available.
2 Gallons per square -foot per day.
Table 2-2: Membrane Element Characteristics
Parameter
Value
Membrane Manufacturer
Membrane Element Model Number
Size of Element Used in Study
Active Membrane Surface Area per Element
Molecular Weight Cut-Off
Membrane Material Construction
Membrane Hydrophobicity
Reported Membrane Charge
Spacer Thickness
Scroll Width
Design Pressure
Design Flux at Design Pressure
Variability of Design Flux
Design Specific Flux at 25 °C
Standard Testing Recovery
Standard Testing pH
Standard Testing Temperature
Design Cross-Flow Velocity
Maximum Flow Rate to an Element
Minimum Flow Rate to an Element
Required Feed Flow to Permeate Flow Ratio
Maximum Element Recovery
Rejection of Reference Solute and Conditions of Test (e.g., Solute type and
concentration)
Variability of Rejection of Reference Solute
Acceptable Range of Operating Pressures (psi, bar)
Acceptable Range of Operating pH Values
Typical Pressure Drop across a Single Element
Maximum Permissible Silt Density Index (SDI)
Maximum Permissible Turbidity
Chlorine/Oxidant Tolerance
Suggested Cleaning Procedures
Applied
M-T4040 ALE
4" X 40"
82ft2
80- lOODaltons
Dow Filmtec
Hydrophobic
Negative
31 mil
38 inches
ISOpsi
34gfd
± 15%
0.24 gfd/psi
50-75%
8
25°C
0.6ft/s
16 gallons per minute (gpm)
4 gpm
1:5
75%
80-99%
-0%, +1%
Dependent on Water Temperature
2- 11
6 psi
4
1 NTU
With Carbon Pre -Filter
M-l 5,000 RO Treatment System
has a self-flush procedure.
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2.2 Operating Process
RO is a pressure-driven process, with the pressure used for separation by allowing fresh water to
move through a membrane, leaving various dissolved constituents of the water behind.
Scientists have explored this concept since the turn of the century, but commercialization for
desalting water for municipal purposes has occurred in only the last 30 to 40 years.
For this separation process, water from a pressurized saline solution is separated from the
dissolved inorganic and organic compounds by flowing through a membrane. No heating or
phase change is necessary for this separation. The major energy required for desalting is for
pressurizing the feed water. The saline feed water is pumped into a closed vessel where it is
pressurized against the membrane. As a portion of the water passes through the membrane, the
remaining feed water increases in salt content. At the same time, a portion of this feed water is
discharged without passing through the membrane.
The amount of water that can be passed through the membrane is frequently controlled to avoid
problems with precipitation of super-saturated salts and increased osmotic pressure across the
membranes. The amount of the feed water discharged to waste in the concentrate stream varies
from 15 to 70% of the feed low, depending on the inorganic composition of the feed water,
pressure, and type of membrane. The RO membranes vary in their ability to reject the passage
of inorganics, including the various arsenic compounds detected in the environment.
As this treatment does not destroy arsenic, the total mass of arsenic exiting the system equals the
mass entering the system. Consequently, the amount of arsenic that has been "removed" from
the permeate (treated water) can be found in the wasted concentrate.
Referring to Figure 2-1, the M-15,000 RO Treatment System used in the verification testing
included:
3 Hp single phase motor and stainless steel centrifugal pump,
Pre-filter for removal of small debris (sediment, rust, and other suspended solids) and
residual chlorine (first 18 days of testing) and a cartridge pre-treatment filter (last 13 days
of testing) (see Photograph 3),
Panel mounted flow meters (to monitor permeate, concentrate, and recycle flow),
Recycled water flow meter (not a standard part for the M-15,000 RO Treatment System)
located on the recycle line prior to cartridge pre-filter,
Manual recirculation needle control valve,
Panel mounted digital conductivity meter (permeate water),
Membrane test ports,
Glycerin filled pressure gages (used to monitor inlet and feed water pressure),
Six stainless steel pressure vessels, and
Six 4" x 40" RO modules.
10
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Photograph 3: Pre-Filter to Watts Premier M-15,000 RO Treatment System
The inlet and feed water pressure were monitored by the glycerin filled pressure gages that had a
range of 0 to 300 psi. The permeate and concentrate flow rates were measured by the panel
mounted flow meters that had a range of 0-20 gpm. The recycle flow meter also had a range of 0
to 20 gpm.
Specific feed water operating parameters, electrical and drain requirements, as well as additional
specifications for the M-15,000 RO Treatment System are presented in Table 2-3.
Table 2-3: Watts Premier M-15,000 RO Treatment System Specifications
Specifications
M-15,000 RO System
Dry Weight
Wet Weight
Feed Water Parameters
Temperature
Max Feed Flow Rate
pH
Maximum Hardness
Maximum TDS
Maximum Iron
Pressure
Drain Connection Requirements
Floor Sink Minimum within 10' of RO system
Electrical Requirements
RO Processor Optional 220V
Delivery Pump
950 Ibs
4900 Ibs
35tolOO°F
24 gpm
2 to 11
290 mg/L
2500 mg/L
0.1 mg/L
50 to 150 gauge pressure (psig)
1 %" connection
220 volts/11.5 amps
115 volts/12.4 amps
The flow rate was regulated by a flow meter and control valve to maintain a constant flow, which
were mounted on the RO control panel. Raw water was supplied to the verification testing unit
11
-------
using a pressurized feed line (approximately 80 to 90 psi) and a 3 Hp centrifugal pump was used
to increase the pressure to the RO operating conditions of -150 psi. The raw water
(approximately at 24 gpm) was first passed through a 20" carbon bloc pre-filter to remove any
small debris, other suspended solid particles, and residual chlorine. The carbon pre-filter was
replaced with a 20-micron sediment pre-filter (20 inch, Watts Premier Big Blue pleated sediment
filter; the Watts Premier poly spun sediment filter model number WP204020 may also be used)
after 18 days of operation, due to a high replacement rate (approximately every 7 days) of the
carbon pre-filter.
12
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Chapter 3
Methods and Procedures
3.1 Quantitative and Qualitative Evaluation Criteria
The objectives of the ETV were to evaluate the equipment in the following areas:
Performance relative to the manufacturer's (Watts Premier) stated range of equipment
capabilities,
The impacts on performance of variations in feed water quality (such as TDS, hardness,
temperature, pH, alkalinity and iron),
The logistical, human and economic resources necessary to operate the equipment, and
The reliability, ruggedness, cost factors, range of usefulness and ease of operation of the
equipment.
In order to address these objectives, the ETV employed the quantitative and qualitative factors
listed in Table 3-1 in evaluating the RO equipment performance.
Table 3-1: Quantitative and Qualitative Evaluation Criteria
Quantitative Factors Qualitative Factors
Flux Ease of operation
Feed water recovery Safety
Finished water quality Susceptibility to environmental conditions
Range of feed water quality that were treated Ruggedness
successfully Impact of operator experience on successful
Power consumption operation
Maintenance requirements Portability of equipment
Required level of operator attention Modular nature of equipment (ease of capacity
Spatial requirements expansion)
Feed flow requirements
Discharge requirements
Waste disposal
The primary applications of RO are the removal of dissolved inorganic and organic
contaminants. In the case of this ETV test, the primary application was arsenic removal.
3.2 Key Treated Water Quality Parameters
3.2.1 Key Groundwater Quality Parameters the Equipment is Designed to Address
The operating range of the manufacturer's RO membrane is summarized in Table 3-2.
13
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Table 3-2: Operating Range of Watts Premier RO Membrane
Parameter Range
Arsenic Less than 350
IDS Less than 2,500 mg/L
Hardness Less than 290 mg/L
Iron Less than 0.1 mg/L
pH 2 to 11
Chlorine exposure Not chlorine tolerant without a carbon filter (which was
included during a portion of the study)
1 For verification testing, the range of arsenic was anticipated to be < 50 (ig/L.
3.2.2 Key Treated Water Quality Parameters for Evaluating Equipment Performance
Key treated water quality parameters that were employed for evaluation of the manufacturer's
RO system equipment are listed in Table 3-3.
Table 3-3: Key Treated Water Quality Parameters
Water Quality Inorganic Parameters Other Parameters
Temperature Arsenic Langelier Saturation Index (LSI)
Alkalinity Conductivity SDI
Hardness Silica
pH Fluoride
Turbidity Iron
TOC Manganese
Chloride Sulfate
Free and Total Chlorine Chromium
Vanadium
TDS
TSS
Calcium
Barium
3.3 Calculations
3.3.1 Calculation of Statistical Uncertainty
The count, average, minimum, and maximum values were tabulated for all data sets. For the
water quality parameters described above, 95% confidence intervals were calculated for
parameters with more than eight data points. The following equation was used for confidence
interval calculation:
Confidence Interval = X +1
where: X = sample mean;
S = sample standard deviation;
14
-------
n = number of independent measurements included in the data set; and
t = Student's t distribution value with n-1 degrees of freedom;
oc= significance level, defined for 95% confidence as: 1-0.95 = 0.05.
According to the 95% confidence interval approach, the a term is defined to have the value of
0.05, thus simplifying the equation for the 95% confidence interval in the following manner:
( s^
95% Confidence Interval = X ±tn_l0975\ =
With input of the analytical results for pertinent water quality parameters into the 95%
confidence interval equation, the output is presented as the sample mean value plus or minus the
second term. The results of this statistical calculation are presented as a range of values falling
within the 95% confidence interval.
3. 3. 2 Calculation and Definition of Operational Parameters
The following are definitions used in the calculations presented within this section:
Permeate water is defined as the water produced by the RO membrane process.
Feed water is defined as the water introduced to the membrane element (no recycled water).
Inlet water is the combination of the feed water and the recycled concentrate water.
Concentrate water is the concentrated waste stream produce by the RO membrane process.
Recycled water is a portion of the concentrate water recirculated back through the RO membrane
process, blended with feed water entering into membranes 1 and 4.
Permeate flux is the flow of permeate divided by the surface area of the membrane.
Permeate flux was calculated according to the following formula:
(3D
where: Jt = permeate flux at time t (gfd)
Qp = permeate flow (gallons per day (gpd))
S = membrane surface area (ft2)
15
-------
Temperature Adjustment for Flux Calculation: Temperature corrections to 25°C for permeate
flux and specific flux were made to correct for the variation of water viscosity with temperature.
The following empirically derived equation was used to provide temperature corrections for
specific flux calculations:
-0.0239(1-25)
rt (at 25 °C) =
(3.2)
where: Jt = permeate flux at time t (gfd, L/(h-m2))
Qp = permeate flow (gpd, L/h)
S = membrane surface area (ft2,
T = temperature of the feed water (°C)
m2)
Net Driving Pressure: The Net Driving Pressure is the pressure available to drive water
through the membrane, equal to the average feed pressure (average of feed pressure and
concentrate pressure) minus the differential osmotic pressure, minus the permeate pressure:
NDP =
(Pf+Pc)
(3.3)
where: NDP = net driving pressure for solvent transport across the membrane (psi, bar)
Pf = inlet pressure to the feed side of the membrane (psi, bar)
Pc = concentrate pressure on the concentrate side of the membrane (psi, bar)
Pp = permeate pressure on the treated water side of the membrane (psi, bar)
ATI = osmotic pressure (psi)
Osmotic Pressure Gradient: The term osmotic pressure gradient refers to the difference in
osmotic pressure generated across the membrane barrier as a result of different concentrations of
dissolved salts. The following equation provides an estimate of the osmotic pressure across the
semi-permeable membrane through generic use of the difference in TDS concentrations on either
side of the membrane:
+TDSC)'
-TDS
I psi
100
mg
(3.4)
where: TDSi = inlet water (feed water + recycled water) TDS concentration (mg/L)
TDSC = concentrate TDS concentration (mg/L)
TDSP= permeate TDS concentration (mg/L)
The inlet water (feed water plus recycled water) characteristics were calculated based on the feed
water, permeate, and concentrate TDS and conductivity.
16
-------
Note that the different proportions of monovalent and multivalent ions composing the TDS will
influence the actual osmotic pressure, with lower unit pressures resulting from multivalent
species. The osmotic pressure ratio of 1 psi per 100 mg/L is based upon TDS largely composed
of sodium chloride. In contrast, for TDS composed of multivalent ions, the ratio is closer to 0.5
psi per 100 mg/L TDS. This was accounted for during verification testing.
Specific Flux: The term specific flux is used to refer to permeate flux that has been normalized
for the net driving pressure. The equation used for calculation of specific flux is given by the
formula provided below. Specific flux is usually discussed with use of flux values that have
been temperature-adjusted to 25°C:
(3.5)
where: NDP = net driving pressure for solvent transport across the membrane (psi, bar)
Jt = permeate flux at time t (gfd, L/(h-m2)). Temperature- corrected flux values were
employed.
Water Recovery: The recovery of feed water as permeate water is given as the ratio of
permeate flow to feed water flow:
Yo System Recovery = 100
(3.6)
where: Qf = feed water flow to the membrane (gpm, L/h)
Qp = permeate flow (gpm, L/h)
Recycle Ratio: The recycle ratio represents the ratio of the recycle flow from the membrane
concentrate to the total flow of water that is used as feed water flow to the membrane. This ratio
provides an idea of the recirculation pumping that is applied to the membrane system to reduce
membrane fouling and specific flux decline.
Q,
RecycleRation=
(37)
where: Qr = recycle water flow rate (gpm)
Qf = feed water flow rate (gpm)
17
-------
Solute Rejection: Solute rejection is controlled by a number of operational variables that must
be reported at the time of water sample collection. Bulk rejection of a targeted inorganic
chemical contaminant were calculated by the following equation:
% Solute Rejection = 100
(3.8)
where: Cf = feed water concentration of specific constituent (mg/L)
Cp = permeate concentration of specific constituent (mg/L)
Note: the feed water concentration does not include the recycled water.
Solvent and Solute Mass Balance: Calculation of solvent mass balance was performed during
Task 1 in order to verify the reliability of flow measurements through the membrane.
Calculation of solute mass balance across the membrane system was performed as part of Task 3
in order to estimate the concentration of total arsenic at the membrane surface.
Qf=QP + Qcw (3.9)
QfCf=QpCp + QcwCc (3.10)
where: Qf = feed water flow to the membrane (gpm, L/h)
Qp = permeate flow (gpm, L/h)
Qcw = concentrate (wastewater) flow (gpm, L/h)
Cf = feed water concentration of specific constituent (mg/L)
Cp = permeate concentration of specific constituent (mg/L)
Cf = concentrate concentration of specific constituent (mg/L)
Solubility Product: Calculation of the solubility product of selected sparingly soluble salts was
performed to determine if there were operational limitations caused by the accumulation of
limiting salts at the membrane surface. Textbook equilibrium values of the solubility product
were compared with solubility values calculated from the results of experimental verification
testing, as determined from use of the following equation:
(3.H)
where: Ksp = solubility product for the limiting salt being considered
y = free ion activity coefficient for the ion considered (i.e., A or B)
[A] = molar solution concentration of the anion A for sparingly soluble salt AxBy
[B] = solution concentration of the anion B
x, y = stiochiometric coefficients for the precipitation reaction of A and B
18
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Mean Activity Coefficient: The mean activity coefficients for each of the salt constituents were
estimated for the concentrated solutions as a function of the ionic strength:
lagyAJI= -0.509-
(3.12)
where: y = free ion activity coefficient for the ion considered (i.e., A or B)
ZA = ion charge of anion A
ZB = ion charge of cation B
(j, = ionic strength
Ionic Strength: A simple approximation of the ionic strength was calculated based upon the
concentration of the IDS in the feed water stream:
(3.13)
where: (J, = ionic strength
IDS = total dissolved solids concentration (mg/L)
3.4 Testing Schedule
The ETV schedule is presented in Figure 3-1. The testing took place over a total period of
approximately eight weeks beginning during the second week of April 2004, and ending in late
May 2004. The five tasks are described in further detail in Sections 3.7 and 4.1.
Task
1
2
3
4
5
Descrintion
Preparation, Coordination, and Setup
Membrane Operation
Cleaning Efficiency
Feedwater and Treated Water Quality Monitoring
Data Handling Protocol
Quality Assurance Project Plan
Year - 2004
12-Acr 19-Acr 26-Acr 3-Mav 10-Mav 17-Mav 24-Mav 7-Jun
I
I
Figure 3-1: RO verification testing schedule.
Verification testing activities included equipment set-up, initial operation, verification operation,
membrane cleaning, and sampling and analysis. Initial operations were conducted so that
equipment could tested and to be sure it is functioning as intended.
19
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3.5 Operation and Maintenance
The manufacturer's operation and maintenance (O&M) documentation for the M-15,000 RO
Treatment System was reviewed prior to the verification testing. The O&M manual for the M-
15,000 RO Treatment System may be found in Appendix A of this report. In addition, the
following aspects of operability are addressed in this report:
Fluctuation of flow rates and pressures through membrane unit - the time interval at
which resetting is needed (i.e., how long can feed pumps hold on a set value for the feed
rate?)
Presence of devices to aid the operator with flow control adjustment?
Was transmembrane pressure measurement provided?
Was recycle ratio measurement provided?
Was feed water recovery measurement provided?
Was rate of flow of raw water measured?
Did the plant have an indicator if the sediment pre-filter was changed ahead of scheduled
quarterly maintenance schedule?
Did the carbon pre-filter adequately remove chlorine?
3.6 Field Operations Procedures
Testing of the M-15,000 RO Treatment System was conducted by an NSF-qualified FTO, MWH.
Water quality analytical work that was carried out as a part of the verification testing plan, was
conducted by MWH Laboratories. All arsenic analyses were conducted by MWH Laboratory.
Field analytical work was performed by MWH field personnel using field laboratory equipment
and procedures for pH, temperature, conductivity, chlorine, turbidity, alkalinity, and hardness.
The verification unit was operated 24 hours a day, seven days a week with staff on-site each day
to operate the verification unit and collect water quality data during one eight-hour shift. Tasks
performed by the operations staff are described in detail below.
3.7 Environmental Technology Verification Testing Plan
The following section provides a brief overview of the tasks included in the initial
characterization tests and the tasks included in the M-15,000 RO Treatment System verification
testing plan. The verification tasks included:
Task 1: Membrane Operation
Task 2: Cleaning Efficiency
Task 3: Feed water and Treated Water Quality Monitoring
Task 4: Data Handling Protocol
Task 5: Quality Assurance Project Plan (QAPP)
Verification testing activities included equipment set-up, initial operation, verification operation,
and sampling and analysis. Initial operations were conducted so that equipment could be tested
20
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to be sure it was functioning as intended. An overview of each task is provided below with
detailed information following this section of the report.
3.7.1 Task 1: Membrane Operation
The objective of this task was to evaluate the RO membrane system operation. System
performance was evaluated relative to the stated water quality goals specified by the
manufacturer. Membrane productivity, rate of specific flux decline, and rejection capabilities
were evaluated at one set of operating conditions for the testing period.
3.7.2 Task 2: Cleaning Efficiency
The objective of this task was to evaluate the efficiency of the membrane cleaning procedures
recommended by the manufacturer. Watts Premier recommends replacement of the RO modules
based upon efficiencies of TDS reduction per module. TDS reduction of the membranes would
need to be monitored in order to determine if replacement of the membranes is necessary. Watts
has stated that the M-15,000 RO Treatment System has a built in flushing procedure; however,
since the verification test was run continuously, the system did not go through this flushing
procedure. However, at the conclusion of the testing period, the cartridge sediment pre-filter and
RO module O-rings were replaced according to the manufacturer's recommended quarterly
maintenance procedures. While not part of the quarterly maintenance procedures, two of the
membranes (membrane number 5 and 6) were also replaced during the maintenance procedures.
The operational performance following these maintenance procedures was recorded and
presented in Chapter 4 of this report.
3.7.3 Task 3: Feed Water and Treated Water Quality Monitoring
The objective of this task was to evaluate the quality of water produced by the membrane system
and the removal of inorganic chemical contaminants achieved by the membrane system at the
specified operational conditions. Monitoring of the water quality parameters included the
following: arsenic (total, dissolved and As (III)), pH, feed water temperature, chloride,
conductivity, calcium, barium, hardness, chlorine, TDS, alkalinity, LSI, turbidity, TSS, silica,
fluoride, iron, manganese, sulfate, chromium, vanadium, TOC and SDL Water quality produced
was evaluated in relation to feed water quality and operational conditions. Mass balances were
calculated to determine the accumulation of limiting salts on the membrane surface. Post-
treatment capabilities of the equipment were also evaluated for arsenic (total, As+3, and
dissolved), pH adjustment, corrosion control, and removal of carbon dioxide from the permeate.
An overview of the equipment operational and production characteristics evaluated for each task
of the verification testing is provided in Table 3-4.
21
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Table 3-4: Equipment Operational Characteristics to be Evaluated in Each Task
Equipment Operational Characteristic to be Evaluated Task
1.
2
3.
4.
5.
6.
7.
8.
9.
10.
11.
Feed water flow rate
Permeate flow rate
Concentrate flow rate
Inlet and Outlet pressures to membrane element
Permeate pressure
Feed water temperature
Recycle Ratio
Power consumption
Permeate stream characterization
Calculation of limiting salt concentrations
Waste stream characterization and range of waste stream flow rates
1
1
1
1
1
1
1
1
3
o
J
1 and 3
3.7.4 Task 4: Data Handling Protocol
The objective of this task was to establish an effective field protocol for data management at the
field operations site and for data transmission between the FTO and NSF during verification
testing. Prior to the beginning of field testing, the database or spreadsheet design were
developed by the FTO and reviewed and approved by NSF. This insured that the required data
was collected during the testing, and that results could be effectively transmitted to NSF for
review.
3.7.5 Task 5: Quality Assurance Project Plan (QAPP)
An important aspect of verification testing is the Quality Assurance Project Plan (QAPP)
developed for QA/QC. The objective of this task was to assure accurate measurement of
operational and water quality parameters during membrane equipment verification testing.
3.8 Task 1: Membrane Operation
Membrane operation was evaluated in Task 1, with quantification of temperature-corrected rate
of specific flux decline and water recoveries. The rates of specific flux decline were used to
demonstrate membrane performance at the specific operating conditions to be verified.
Monitoring in Task 1 was focused on determination of the system operational characteristics
(e.g., arsenic removal, flux, temperature-corrected specific flux, recovery, etc.). An NSF field
inspection of equipment operations, sampling, and field analysis procedures was carried out
during the initial test runs in Task 1 (results presented in Chapter 4).
Rate of temperature-corrected specific flux decline is a function of water quality and operational
strategy. Many additional factors influence specific flux decline with RO membranes including
membrane compaction, inorganic scaling, particulate or organic fouling, biofouling, and other
factors. In this task, specific flux decline was monitored to evaluate operational trends.
Chemical characterization of the feed waters and permeate water stream with calculation of
membrane rejection capabilities were performed as part of Task 3. Additionally, calculation of
the operational limitations caused by limiting salt concentrations was also performed in Task 3.
22
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3.8.1 Experimental Objectives
The objectives of Task 1 were to demonstrate the following: 1) the appropriate operational
conditions for the membrane equipment; 2) the feed water recovery achieved by the membrane
equipment at the designated operational conditions; and 3) tie rate of specific flux decline
observed over extended membrane filtration operation during the testing period. This task was
also intended to provide operational power consumption information that could be used to
develop cost estimates for O&M of the equipment. Complete chemical and physical
characterization of the feed waters and treated waters produced by the system, with calculation
of limiting salt concentrations, were performed as part of Task 3.
It should be noted that the objective of this task was not process optimization, but rather
verification of membrane operation at the operating conditions specified by the FTO, as pertains
to permeate flux and transmembrane pressure.
3.8.2 Work Plan
Site preparation, coordination, mobilization and start-up of equipment were performed prior to
the initiation of Task 1 testing. Furthermore, the RO membrane treatment system had achieved a
condition of steady-state operation prior to the start of Task 1 testing.
After set-up and shakedown of the membrane equipment, RO operation was established at a
specific flux of 0.38 gfd/psi with a feed water recovery of 69%. It was intended that the
membrane system would be operated continuously for a minimum of one month. However, the
system automatically shut itself down twice during the verification testing, and was not in
operation for a total of four days during the verification testing period. The system was operated
for a total of 27 days during the verification test. A summary of the operational parameters
recorded during Task 1 and the minimum frequency of monitoring are presented in Table 3-5. A
summary of the water recovery and specific flux may be found in Tables 4-3 (Section 4.2.1.3)
and Table 4-6 (Section 4.2.1.5) respectively.
Samples were collected from lab valves mounted on the panel coming from Vi" ball valves teed
into the permeate line (permeate), 1" bulk fittings mounted on the top of the unit (concentrate),
1" port on the top of the unit (inlet), and a 1" housing on the side of the panel (feed water). The
inlet and feed water pressure were monitored by the glycerin filled pressure gages that have a
range of 0 to 300 psi, and the permeate and concentrate flow rates were measured by the panel
mounted flow meters that have a range of 1 to 20 gpm. For a standard M-15,000 RO Treatment
System, the recycle ratio is not a measured operational parameter. However, for the purpose of
verification testing, a flow meter was placed on the recycle line to calculate the recycle ratio.
23
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Table 3-5: Frequency and Type of Operating Data
Operational Parameter
Action, Monitoring Frequency
Feed Water, Permeate, Recycle, and Concentrate Flow
Rates
Membrane Element Inlet and Feed Water Pressures
Recovery
Recycle Ratio
IDS Concentration in Feed water, Concentrate,
Permeate
Feed water Temperature
Horsepower and Efficiency of Motors, and Consumed
Amperage for RO Treatment
Concentrate Composition For Disposal
Checked and recorded twice daily. Adjusted when 10%
above or below target. Recorded both before and after
adjustment. The feed water flow rate was monitored
twice daily by summing the permeate and concentrate
flow rates.
Checked and recorded twice daily.
Calculated and recorded twice daily. Adjusted when
10% above or below target.
Calculated and recorded twice daily. Adjusted when
10% above or below target.
Calculation of osmotic pressure gradient on a daily
basis.
Recorded twice daily.
Provided record of pumping requirements, current draw
to motors on cumulative basis, power factor and
recorded daily from a power totalizer.
Sampled waste stream once per week during the 31 -day
testing period.
When a specific flux decline of 20% occurred before the operating period was completed,
adjustments to the operational strategy were made (such as a decrease in nominal flux or
recovery). Decisions on which adjustments were made were based upon the manufacturer's
experience and consultation with the FTO conducting the study.
3.8.3 Analytical Schedule
Measurement of membrane performance parameters were monitored a minimum of 2 times per
day, as indicated in Table 3-5. Temperature measurements were made on a daily basis in order
to provide data for temperature correction of specific flux and for reporting of solute rejection
(addressed in Task 3).
Power use for the operation of the RO system was monitored with a power totalizer. Power
measurements were recorded daily by MWH during the verification test.
The characteristics of feed waters used during the testing period were explicitly reported with the
compiled results from membrane flux, specific flux and recovery monitoring. The TDS
concentrations in the inlet water (combined feed water and recycled water), permeate and
concentrate streams were used to calculate the osmotic pressure gradient (Equation 3.4) across
the membrane on a daily basis. Osmotic pressure gradient value was used to calculate net
driving pressure and specific flux on a daily basis.
3.8.4 Evaluation Criteria and Minimum Reporting Criteria
General operational performance (provided in Chapter 4):
=> Graph of specific flux normalized to 25°C (Equation 3.5) vs. time over the
verification testing period.
24
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=> Temporal profile of net driving pressure normalized to 25°C (Equation 3.3) over
the verification testing period.
=> Temporal profile of water recovery (Equation 3.6) over the verification testing
period. One temporal profile graph has been provided for the water quality
evaluated.
=> Temporal profile of the concentrate flow and other waste stream flows produced
during the verification testing period.
Power consumption (provided in Chapter 4):
=> A table of horsepower requirements, motor efficiency and consumed amperage for
the testing period has been provided, as measured for the set of operational
conditions during the verification testing period.
Concentrate stream characterization (See Chapter 4, Task 3 for the water quality
characteristics of the concentrate, permeate, and feed water):
=> A table of concentrate stream quality parameters measured during the verification
testing period has been provided.
3.9 Task 2: Cleaning Efficiency
While no chemical cleaning procedure was provided by the manufacturer, regularly scheduled
maintenance of the system includes quarterly replacement of the pre-filter and RO module O-
rings, and replacement of the BD modules based on efficiencies of TDS reduction per filter
module. At the end of the testing period, the cartridge sediment pre-filter and RO module O-
rings were replaced. In addition to replacing the pre-filter and RO module O-rings, two of the
membranes were replaced (membrane number 5 and 6). Measurement of membrane
performance parameters following this maintenance were recorded and presented in Chapter 4.
3.9.1 Experimental Objectives
The objective of this task was to evaluate the manufacturer's recommended maintenance
procedures for ensuring reasonable operational parameters are maintained during throughout the
treatment life of the membrane modules. This task was considered a "proof of concept" effort,
not an optimization effort.
3.9.2 Work Plan
The membrane system has the potential to experience specific flux decline during the membrane
test run conducted for Task 1. If a 20% decline of specific flux were detected, the modules were
to be replaced and the system would then undergo the recommended maintenance procedures
specified by the manufacturer. Following the maintenance procedures, the system was restarted
and the initial conditions of specific flux, recovery and inorganics (arsenic) rejection capabilities
were tested.
As the manufacturer recommends replacement of fouled modules, no chemical cleaning
procedures were provided. Furthermore, since chemical cleanings are not recommended,
disposal of spent cleaning agents is not relevant.
25
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3.9.3 Analytical Schedule
Flow rates, pressures, recovery, and temperature data were collected immediately prior to and
immediately after performing any manufacturer's scheduled quarterly or annual maintenance
procedures. Based on this information, any changes in the temperature adjusted specific flux
were determined. Two primary indicators of conventional cleaning efficiency and restoration of
membrane productivity were examined in this task:
1) The immediate recovery of membrane productivity, as expressed by the ratio between the
final specific flux ralue of the current filtration run (Jtmf) and the initial specific flux (Jtm;)
measured for the subsequent filtration run:
"/
% Recovery of specific Flux =100
tm /
(3.14)
where: Jtmf = Final specific flux (gfd/psi, L/(h-m2)/bar) at end of the previous run
Jtmi = Initial specific flux (gfd/psi, L/(h-m2)/bar) at the beginning of the current
run.
2) The loss of specific flux capabilities, as expressed by the ratio between the initial specific
flux for any given filtration run (Jtmi) divided by the original specific flux measured at the
initiation of operation for the first filtration run in a series (Jtmio):
% Loss of Original specific Flux =100
Jt,
(3.15)
where: Jtmio = Original Specific flux (gfd/psi, L/(h-m2)/bar) measured at the initiation of
membrane testing.
3.9.4 Evaluation Criteria and Minimum Reporting Requirements
The minimum reporting requirements include presentation of the following results
Specific flux recovery:
=> A table is provided in Chapter 4 of post maintenance specific flux recoveries
during the period of operation.
Maintenance efficiency:
=> A table is provided in Chapter 4 of the maintenance efficiency indicators
described above for the maintenance procedures performed during the period of
operation.
Assessment of irreversible loss of specific flux and estimation of usable membrane life
for costing purposes.
26
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3.10 Task 3: Water Quality Monitoring
The water quality data for the feed water (chlorinated groundwater), the membrane permeate and
concentrate streams were collected during the verification testing as part of Task 1. A list of the
water quality parameters monitored during equipment verification testing is provided in Table 3-
6.
Table 3-6: Sampling Schedule and Methods for Feed, Permeate, & Concentrate Water
Parameter
Arsenic (total)
Arsenic (As+3 and dissolved)
pH
Conductivity
TDS
Alkalinity
Hardness
LSI
Turbidity
Temperature (feed only)
TSS
Silica
Calcium
Barium
Fluoride
Iron
Manganese
Sulfate
Chlonde
Chromium
Vanadium
TOC
SDI4
Chlorine (total and free)5
Frequency1
I/day
I/week
I/day
2/day
I/day
I/week
I/week
1 /month
I/week
2/day
I/week
I/week
I/week
I/week
I/week
I/week
I/week
I/week
I/week
I/week
I/week
I/week
1 /month
4/week
Facility
Laboratory
Laboratory
On-site
On-site
Laboratory
On-site
On-site
By Calculation
On-site
On-site
Laboratory
Laboratory
Laboratory
Laboratory
Laboratory
Laboratory
Laboratory
Laboratory
Laboratory
Laboratory
Laboratory
Laboratory
Laboratory
On-site
Standard
Method2
4500-H+ B
2510 B
2540 C
2130 B
2550
2540 D
4500 FC
5310 C
ASTM
D4189-95
EPA
Method3
200.8
200.8
200.7
200.7
200.8
200.7
200.8
300.0
300.0
200.8
200.8
Hach
Method
8221
8226
8167 (total)
8021 (free)
1 The verification plant was staffed seven days per week.
2 Standard Methods 20th Edition.
^ "IVTptliork for trip Fiptprminfltio-
n of IVTptnls in
Fnvironmpritfll Siarr
mlp^-Sliirvnlpmpr
it T" FPA/finn/i
R-Q4/111 Mnv 1 QQ4
Available at (NTIS) PB95-125472.
4 SDI was analyzed on the feed water only.
5 Total and free chlorine were monitored prior to the pre-filter and after the first membrane to monitor the chlorine removal.
3.10.1 Experimental Objectives
The objective of this task was to assess the treatment capability of the membrane equipment to
remove arsenic based on water quality conditions at the site. Mass balances were performed as
part of this task in order to evaluate the concentration of rejected species at the membrane
surface during membrane operation. Calculation of the recovery limitation caused by limiting
salts was performed to determine the impact of feed water quality on membrane operation. The
count, average, minimum, and maximum values were tabulated for all data sets. Statistical
analysis (standard deviation and confidence intervals), were performed on all analytes with eight
27
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or more discrete samples collected over the verification period. The median, minimum,
maximum, and count were presented for each pH data set.
3.10.2 Work Plan
Monitoring of water quality parameters in the feed water, permeate and concentrate water
streams allowed the calculation of percent rejection of the measured parameters and targeted
inorganic chemical contaminants for the specific operational conditions evaluated. Estimation of
the percent rejection of arsenic (total) was based upon the equation for solute rejection provided
in the Section 3.3.2, Equation 3.8.
Many of the water quality parameters described in this task were measured on-site by the NSF-
qualified FTO. Analysis of the remaining water quality parameters were performed by MWH
Laboratories, a state certified laboratory. The methods used for measurement of water quality
parameters are identified in Table 3-6. A number of the analytical methods utilized in this study
for on-site monitoring of feed, permeate, and concentrate water qualities are further described in
Task 5, Quality Assurance Project Plan. These analytical methods include pH, conductivity,
turbidity, alkalinity, hardness, chlorine, and temperature.
For the water quality parameters submitted to MWH Laboratories, water samples were collected
in appropriate containers (containing necessary preservatives as applicable) prepared by MWH
Laboratories. These samples were then preserved, stored, shipped, and analyzed in accordance
with appropriate procedures and holding times.
3.10.3 Analytical Schedule
Feed Water, Permeate and Concentrate Characterization
During the testing period, the feed water, permeate and concentrate water streams were
characterized at a single set of operating conditions. The water quality monitoring requirements
are provided in Table 3-6.
Water Quality Sample Collection
Water quality data were collected at the specified intervals during each testing period. The
monitoring frequency for the water quality parameters is provided in Table 3-6. To the extent
possible, analyses for inorganic water quality parameters were performed on water sample
aliquots obtained simultaneously from the same sampling location, in order to ensure the
maximum degree of comparability between water quality analytes.
The TDS concentrations in the feed water, permeate and concentrate streams were used to
calculate the ionic strength of the feed water and concentrate streams, as well as osmotic pressure
gradient across the membrane on a daily basis (see Chapter 4). Osmotic pressure gradient value
was then used for calculation of net driving pressure and specific flux on a daily basis. Mass
balances for specified water quality parameters [arsenic (total, As+3, and dissolved), silica,
fluoride, iron, manganese, chloride, barium, calcium and sulfate] were then calculated once per
week. Calculation of the potential for recovery limitation based upon limiting salt concentrations
was performed once per week.
28
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3.10.4 Evaluation Criteria and Minimum Reporting Criteria
Percent removal of inorganic chemical constituents were developed and the following are
presented in Chapter 4:
=> A temporal plot showing concentrations of target inorganic constituents (arsenic,
silica, fluoride, iron, chloride and sulfate) and TDS in the feed water, permeate
and concentrate water streams over the period of operation is presented. A
temporal plot of the manganese concentrations was not presented as all results
(feed water, permeate, and concentrate) were below the minimum reporting limit
(MRL)of2.0ng/L.
=> A table with weekly values of percent removal of target inorganic constituents
[arsenic (total, As+3, As+5 and dissolved), silica, fluoride, iron, manganese,
chloride, barium, calcium and sulfate] and other pertinent water quality
parameters (chromium and vanadium) for the period of operation is presented.
The equations shown in Section 3.3.2 were used to determine percent removal of
all pertinent water quality parameters for verification testing.
=> Mass balances through the membrane testing system for total arsenic were
conducted. The mass balance equation presented in the Section 3.3.2 was used to
calculate the mass of inorganic constituents in different water streams.
=> Limiting salt concentrations (via solubility product calculation Equation 3.11)
were calculated for specific water quality constituents (CaCCh, BaSO/t, and
CaSO/t) once per week. The equation for solubility product calculation as
presented in Section 3.3.2 (Equation 3.11) were used to compare with standard
Solubility Product values to determine if the salt concentration is posing a
limitation to operational system recovery.
Individual water quality and removal goals specified by the manufacturer:
=> Feed, permeate and concentrate concentrations of any measured water quality
parameters are provided in tabular form for the period of operation.
Removal of TSS and Turbidity:
=> A table of feed, permeate, and concentrate water measurements are presented for
TSS during the period of operation.
=> A table of feed, permeate, and concentrate water turbidity measurements are
presented for the period of operation.
3.11 Task 4: Data Handling Protocol
The data management system used in the verification testing involved the use of both computer
spreadsheets and manual recording (on-site logbook) of operational parameters for the
membrane equipment on a daily basis. All field activities were thoroughly documented. Field
documentation included field notebooks, photographs, field data sheets, and chain-of-custody
forms. The following guidelines were followed:
Field notes were kept in a bound logbook,
Field logbook was used to record all water treatment equipment operating data,
Each page was sequentially numbered,
Each page was labeled with the project name and number,
29
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Completed pages were signed and dated by the individual responsible for the entries, and
Errors had one line drawn through them and this line was initialed and dated.
All photographs were logged in the field logbook. These entries included the time, date, and
subject of the photograph, and identified the photographer.
Original field sheets and chain-of-custody forms accompanied all samples shipped to the
analytical laboratory. Copies of field sheets and chain-of-custody forms for all samples are
included in Appendix C.
3.11.1 Experimental Objectives
The objectives of this task were: 1) to establish a viable structure for the recording and
transmission of field testing data such that the FTO provided sufficient and reliable data to NSF
for verification purposes, and 2) to develop a statistical analysis of the data, as described in the
document "EPA/NSF ETV Protocol for Equipment Verification Testing for Removal Of
Inorganic Constituents: Requirements For All Studies" and "EPA/NSF ETV Protocol for
Equipment Verification Testing for Arsenic Removal: Requirements For All Studies."
3.11.2 Work Plan
FTO operators recorded data and calculations by hand in laboratory notebooks. Daily
measurements were recorded on specially prepared data log sheets as appropriate. The original
notebooks were stored on-site; and electronic copies were forwarded to the project manager of
the FTO at least once per week during the testing period. Operating logs included a description
of the membrane equipment (description of test runs, names of visitors, description of any
problems or issues, etc.); such descriptions were provided in addition to experimental
calculations and other items.
A database for the project was set up in the form of custom-designed spreadsheets. The
spreadsheets were capable of storing and manipulating each monitored water quality and
operational parameter from each task, each sampling location, and each sampling time. All data
from the laboratory notebook and data log sheets were entered into the appropriate spreadsheet.
Data entry was conducted on-site by the designated field testing operators. All recorded
calculations were also checked at this time. Following data entry, the spreadsheets were printed
out and the printouts were checked against the handwritten data sheet. Any corrections were
noted on the hard copies and corrected on the screen, and then a corrected version of the
spreadsheet was printed out. Each step of the verification process was initialed by the field
testing operator performing the entry or verification step.
Data from MWH Laboratory were received and reviewed by the field-testing operator. These
data were entered into the data spreadsheets, corrected, and verified in the same manner as the
field data. As available, electronic data storage and retrieval capabilities were employed in order
to maximize data collection and minimize labor hours required for monitoring.
30
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3.12 Task 5: Quality Assurance Project Plan (QAPP)
QA/QC of the operation of the membrane equipment and the measured water quality parameters
were maintained during verification testing through a quality assurance project plan (QAPP) as
described in this section.
3.12.1 Experimental Objectives
The objective of this task was to maintain strict QA/QC methods and procedures during
verification testing. Maintenance of strict QA/QC procedures was important, in that if a question
arose when analyzing or interpreting data collected for a given experiment, it was possible to
verify exact conditions at the time of testing. The elements of the Quality Assurance Project
Plan for the ETV included:
Work Plan,
Monthly QA/QC Verifications,
Data Correctness,
Calculation of Indicators of Data Quality, and
Corrective Action Plan.
3.12.2 Work Plan
Equipment flow rates were measured and recorded on a daily basis. A routine daily walk through
during testing was established to verify that each piece of equipment or instrumentation was
operating properly. In-line monitoring equipment such as flow meters, etc. were checked to
confirm that the readout matches with the actual measurement (i.e. flow rate).
3.12.3 Monthly QA/QC Verifications
The monthly QA/QC verifications included:
Differential pressure transmitters (verify gauge readings and electrical signal using a
pressure meter) and
Tubing (verify good condition of all tubing and connections; replace if necessary).
3.12.4 Data Correctness
Data correctness refers to data quality, for which there are five indicators:
Representativeness,
Statistical Uncertainly,
Precision,
Accuracy, and
Completeness.
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3.12.4.1 Representativeness
As specified by NSF, representativeness of water quality samples for the ETV were ensured by
executing consistent sample collection procedures, including:
Sample locations,
Timing of sample collection, and
Analytical methods, sampling procedures, sample preservation, packaging and transport.
Sample Locations
Sample locations for the Ml5,000 RO Treatment System included the feed water, permeate
(treated water), and concentrate. Only one specific sample tap was used at each of these sample
locations.
Timing of Sample Collection
In the RO verification study, the timing of sample collection was not as critical as in, for
example, a granular media filtration verification study in which the filter run time can influence
the quality of water produced by the filter. For the BD verification study, there is no filter
maturation time, stable period of filter operation, or turbidity breakthrough period. To the extent
possible, analyses for inorganic water quality parameters were performed on water sample
aliquots obtained simultaneously from the same sampling location, in order to ensure the
maximum degree of comparability between water quality analytes.
Analytical Methods, Sampling Procedures, Sample Preservation, Packaging and Transport
The analytical methods and sampling procedures utilized in the verification testing plan for
collecting laboratory samples and for on-site monitoring of feed water, permeate and concentrate
water quality are described below. Field analyses were performed using portable field analytical
equipment. Laboratory samples were collected in bottles prepared by MWH Laboratories with
the appropriate preservative for the analyte. Once collected, the samples were stored in a
refrigerator (4°C) until ready for transport to MWH Laboratories, and the temperature of the
refrigerator were logged daily. The samples were transported in coolers packed with ice. With
the exception of those samples noted in Chapter 4, the samples were analyzed within the
Standard Methods or EPA recommended holding times, if not analyzed on-site.
Samples were collected from lab valves mounted on the panel coming from Vi" ball valves teed
into the permeate line (permeate), 1" bulk fittings mounted on the top of the unit (concentrate),
and a 1" housing on the side of the panel (feed water). To the extent possible, analyses for water
quality parameters were performed on water sample aliquots obtained simultaneously from the
same sampling location, in order to ensure the maximum degree of comparability between water
quality analytes.
Arsenic (Total)
Samples were collected headspace free into polyethylene or borosilicate glass bottles
provided by the analytical laboratory, capped tightly and stored refrigerated. The sample
bottles from the laboratory included the preservative (HNOs) for a holding period of up to
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six months. The samples were analyzed using EPA Method 200.8 within the holding
period of the preserved samples.
Arsenic (As (III) and Dissolved)
Samples were collected on-site and speciated using the procedures (see Appendix B) and
resin columns provided by NSF. The samples were collected in polyethylene bottles
provided by MWH Laboratories (preserved in accordance with the NSF procedures).
The samples were analyzed using EPA Method 200.8 within the holding period of the
preserved samples (six months).
pH
Analyses for pH were performed according to Standard Method 4500-H+B. Samples
were collected and analyzed on-site immediately and the temperature at which the pH
readings were made was recorded. Sample agitation and prolonged exposure to air were
avoided. A three-point calibration of the pH meter used in this study was performed once
per day when the instrument was in use. Certified pH buffers (4.0, 7.0, and 10.0) were
used for the daily calibration. The probe was stored in the appropriate solution defined in
the instrument manual.
Conductivity
Analyses for conductivity were performed according to Standard Method 2510 B.
Samples were collected and analyzed on-site immediately. Sample agitation and
prolonged exposure to air were avoided. A three-point calibration of the conductivity
meter used in verification testing was performed once per day when the instrument is in
use. Certified conductivity solutions (184, 1000, and 1990 umoh/cm) and were used.
The probe was stored in the appropriate solution defined in the instrument manual.
Turbidity
Due to the relatively short holding period of 48-hours, these samples were analyzed on-
site using Standard Method 2130 B with a bench-top turbidimeter. All glassware used
for turbidity measurements were cleaned and handled using lint-free tissues to prevent
scratching. Sample vials were stored inverted to prevent deposits from forming on the
bottom surface of the cell.
The bench-top turbidimeter was calibrated within the expected range of sample
measurements at the beginning of equipment operation and on a weekly basis using
primary turbidity standards of 0.1, 0.5, and 5.0 Nephelometric Turbidity Units (NTU).
The turbidity meter has a range of 0 to 199 NTU. Secondary turbidity standards were
obtained and checked against the primary standards. Secondary standards were used
(4.5, 45.9, and 448 NTU) on a weekly basis to verify calibration of the turbidimeter and
to re-calibrate when more than one turbidity range was used.
The method for collecting grab samples was performed according to the following
protocol: 1) running a slow, steady stream from the sample tap, 2) triple-rinsing a
dedicated sample beaker in this stream, 3) allowing the sample to flow down the side of
the beaker to minimize bubble entrainment, 4) double-rinsing the sample vial with the
sample, 5) carefully pouring from the beaker down the side of the sample vial, 6) wiping
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the sample vial clean, 7) inserting the sample vial into the turbidimeter, and 8) recording
the measured turbidity. There were no issues associated with fogging of the glass vials.
Chlorine
Free and total chlorine were analyzed in the feed water (before the pre-filter) and after the
pre-filter to monitor for chlorine removal. There was no sample port between the pre-
filter and the first membrane; therefore, chlorine was tested after the first membrane.
Analyses for both free and total chlorine were conducted on-site immediately upon
collection of the samples, using Hach's DPD method of analysis, 8167 for total chlorine
and 8021 for free chlorine (both EPA approved methods).
Alkalinity and Hardness
Alkalinity (bicarbonate) and hardness were not target contaminants for arsenic removal
by RO. Thus, they were measured on-site by properly calibrated test kits provided by
Hach. Total alkalinity was measured on-site immediately using Hach's 0.1600 N sulfuric
acid with Hach's titration method (Hach method 8221) with a detection range of 0 to
5,000 mg/L as CaCO3. Total hardness was measured on-site immediately using Hach's
titration method prepared titrants (EDTA Hach method 8226), with a range of 0 to 25,000
mg/LasCaCO3.
All test kits used on-site were calibrated when the equipment was in use, utilizing known
standards at two or more concentration levels. Data obtained with test kits, which utilize
non-standard methods were not used to determine if the system met the applicable
performance criteria.
Temperature
Readings for temperature were conducted on-site immediately after collection in
accordance with Standard Method 2550. Raw water temperatures were obtained twice
daily. The thermometer was a precision thermometer certified by the National Institute
of Standards and Technology (NIST).
TDS
Plastic sample bottles were used, as provided by the analytical laboratory. Analyses were
made as soon as possible due to impracticality of preserving samples, as specified in
Standard Method 2540. Samples were refrigerated until the time of analysis.
TSS
Plastic sample bottles were used, as provided by the analytical laboratory. Analyses were
made as soon as possible due to impracticality of preserving samples, as specified in
Standard Method 2540 D. Samples were refrigerated until the time of analysis.
TOC
Amber glass bottles preserved with H2SO4 were used, as provided by the analytical
laboratory. Analyses were made as soon as possible according to Standard Method 5310
C. Samples were refrigerated until the time of analysis, prior to the 28-day holding
period.
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Iron
Samples were collected headspace free into polyethylene bottles provided by the
analytical laboratory, capped tightly and stored refrigerated. The sample bottles from the
laboratory included the preservative (HNCb) for a holding period of up to six months.
All iron samples were analyzed using EPA Method 200.7 within the holding period of the
preserved samples.
Manganese
Samples were collected headspace free into polyethylene bottles provided by the
analytical laboratory, capped tightly and stored refrigerated. The sample bottles from the
laboratory included the preservative (HNOs) for a holding period of up to six months.
All manganese samples were analyzed using EPA Method 200.8 within the holding
period of the preserved samples.
Sulfate
Samples were collected headspace free into polyethylene bottles provided by the
analytical laboratory, capped tightly and stored refrigerated. All sulfate samples were
analyzed using EPA Method 300.0 within the holding period of the preserved samples.
Chloride
Samples were collected headspace free into polyethylene bottles provided by the
analytical laboratory, capped tightly and stored refrigerated. All chloride samples were
analyzed using EPA Method 300.0 within the holding period of the preserved samples.
Silica
Samples were collected headspace free into polyethylene bottles provided by the
analytical laboratory, capped tightly and stored refrigerated. The sample bottles from the
laboratory included the preservative (HNCb) for a holding period of up to six months.
All silica samples were analyzed using EPA Method 200.7 within the holding period of
the preserved samples.
Chromium
Samples were collected headspace free into polyethylene bottles provided by the
analytical laboratory, capped tightly and stored refrigerated. The sample bottles from the
laboratory included the preservative (HNOs) for a holding period of up to six months.
All chromium samples were analyzed using EPA Method 200.8 within the holding period
of the preserved samples.
Fluoride
Samples were collected headspace free into polyethylene bottles provided by the
analytical laboratory, capped tightly and stored refrigerated. All fluoride samples were
analyzed using Standard Method 4500 FC within the holding period of the preserved
samples (28 days).
Vanadium
Samples were collected headspace free into polyethylene bottles provided by the
analytical laboratory, capped tightly and stored refrigerated. The sample bottles from the
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laboratory included the preservative (HNCb) for a holding period of up to six months.
All vanadium samples were analyzed using EPA Method 200.8 within the holding period
of the preserved samples.
Barium
Samples were collected headspace free into polyethylene bottles provided by the
analytical laboratory, capped tightly and stored refrigerated. The sample bottles from the
laboratory included the preservative (HNOs) for a holding period of up to six months.
All barium samples were analyzed using EPA Method 200.8 within the holding period of
the preserved samples.
Calcium
Samples were collected headspace free into polyethylene bottles provided by the
analytical laboratory, capped tightly and stored refrigerated. The sample bottles from the
laboratory included the preservative (HNOs) for a holding period of up to six months.
All calcium samples were analyzed using EPA Method 200.7 within the holding period
of the preserved samples.
SDI
Sample water was collected in a 5-gallon polyethylene cube-container, headspace free
and shipped overnight to the laboratory for analysis. The American Society of Testing
and Materials (ASTM) test number 4189-95 procedures were followed for the SDI
calculation.
Representativeness of Operational Parameters
As specified by NSF, representativeness for operational parameters entails collecting a
sufficient quantity of data during operation to be able to detect a change in operations.
As specified by NSF, detecting a ±10% change in an operating parameter, such as
pressure, is sufficient. Operational parameters including flow and pressure were recorded
twice per day, which NSF specifies as sufficient for tracking changes in operational
conditions that exceed this 10% range.
Flow Rates
The permeate and concentrate flow rates were verified daily using a calibrated container
and stopwatch method to manually verify the flow rates from the system. While no
adjustments to the panel mounted flow meters was possible, the manual "check" could
verify if the panel mounted flow meters were accurate.
3.12.4.2 Statistical Uncertainty
Statistical uncertainty of the water quality parameters analyzed were evaluated through
calculation of the 95% confidence interval around the sample mean for parameters with eight or
more samples. Description of the confidence interval calculation is provided in Section 3.12.5.
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3.12.4.3 Methodology for Measurement of Precision and Accuracy
Precision and Accuracy for Water Quality Parameters
Tables 3-7 and 3-8 summarize the methodology used in the ETV for the measurement of
precision and accuracy for each water quality analysis performed for the verification study.
Arsenic speciation columns were QA/QC checked by NSF and were provided by NSF for the
verification testing. The sampling location for each duplicate sample was alternated between the
feed water, permeate, and concentrate.
Precision and Accuracy for Operational Parameters
The operational parameters in the ETV included flow rates and pressures. Water flow rates were
verified for all flow meters (located on the permeate and concentrate lines) daily by using a
calibrated container and a stopwatch. The duration of the bucket tests were one minute or
longer, depending on the magnitude of the flow rate.
Spiked Samples
Spiked samples were utilized at MWH laboratory, as presented in Table 3-8. Spiked samples
were applicable for the analyses performed on-site at the treatment system at a 10% frequency,
as presented in Table 3-9.
Table 3-7: Methodology for Measurement of Precision and Accuracy
Parameter
Arsenic (Total)
(report to nearest 1
Mg/L)
pH
(report to nearest 0. 1
pH unit)
Silica
(report to nearest 0. 1
mg/L)
Fluoride
(report to nearest 0. 1
mg/L)
Chromium
(report to nearest 1
Mg/L)
Vanadium
(report to nearest 1
Mg/L)
TOC
(report to nearest 0.5
mg/L)
Chloride
(report to nearest 1
mg/L)
MRL
l.Ong/L
0-14pH
units
0.05 mg/L
0. 1 mg/L
2 Mg/L
10 pg/L
0.5 mg/L
1 mg/L
On-site Duplicate
Frequency
Seven measurements per
week in duplicate (33% of
samples)
Seven measurements per
week in duplicate (33% of
samples)
One sample per week in
duplicate (33% of samples)
One sample per week in
duplicate (33% of samples)
One sample per week in
duplicate (33% of samples)
One sample per week in
duplicate (33% of samples)
One sample per week in
duplicate (33% of samples)
One sample per week in
duplicate (33% of samples)
Acceptable
Precision
30%
10%2
30%
20%
30%
30%
30%
20%
Accuracy
See procedures of MWH
Laboratory (see Table 3-8)
Daily 3-point calibration
with certified pH buffers in
range of measurements
(4.0, 7.0 and 10.0)
See procedures of MWH
Laboratory
(see Table 3 -8)
See procedures of MWH
Laboratory
(see Table 3 -8)
See procedures of MWH
Laboratory
(see Table 3 -8)
See procedures of MWH
Laboratory
(see Table 3 -8)
See procedures of MWH
Laboratory
(see Table 3 -8)
See procedures of MWH
Laboratory
(see Table 3 -8)
37
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Table 3-7: Methodology for Measurement of Precision and Accuracy (continued)
Parameter
MRL
On-site Duplicate
Frequency
Acceptable
Precision
Accuracy
Iron
(report to nearest 0.5
mg/L)
Manganese
(report to nearest 0.5
mg/L)
Sulfate
(report to nearest 1
mg/L)
Temperature
(report to nearest
0.1°C)
Alkalinity
(report to nearest 1
mg/L as CaCO,)
Hardness
(report to nearest 1
mg/L as CaCO,)
Turbidity
(report to nearest
0.05 mg/L)
Conductivity
(report to nearest 0.1
l_imho/cm)
Barium
(report to nearest 0.5
mg/L)
Calcium
(report to nearest 0.5
mg/L)
TSS
(report to nearest 1
mg/L)
SDI
(report to nearest 1
mg/L)
TDS
(report to nearest 1
mg/L)
0.5 mg/L One sample per week in
duplicate (33% of samples)
0.015 mg/L One sample per week in
duplicate (33% of samples)
2 mg/L One sample per week in
duplicate (33% of samples)
NA Two measurements per
week in duplicate (20% of
samples)
10 mg/L One sample per week in
duplicate (33% of samples)
10 mg/L One sample per week in
duplicate (33% of samples)
0.05NTU One sample per week in
duplicate (33% of samples)
4 |imho/cm Eight samples per week in
duplicate (20% of samples)
2 (ig/L One sample per week in
duplicate (33% of samples)
1 mg/L One sample per week in
duplicate (33% of samples)
4 mg/L One sample per week in
duplicate (33% of samples)
1 One sample per month in
duplicate (100% of samples)
10 mg/L Four samples per week in
duplicate (20% of samples)
30% See procedures of MWH
Laboratory
(see Table 3-8)
30% See procedures of MWH
Laboratory
(see Table 3-8)
20% See procedures of MWH
Laboratory
(see Table 3-8)
10%3 Initial and weekly
verification against a NIST
thermometer.
30% Weekly calibration
verification using known
standards at two
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