October 2005
Environmental Technology
Verification Report
MAN-TECH ASSOCIATES INC.
TITRASIP™ SA SYSTEM
CONTINUOUS MULTI-PARAMETER
WATER QUALITY MONITOR
Prepared by
Battelle
Battelle
'Ihe Business
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THE ENVIRONMENTAL TECHNOLOGY VERIFICATION
PROGRAM
&EPA
U.S. Environmental Protection Agency
Battelle
'fne Business oj Innovation
ETV Joint Verification Statement
TECHNOLOGY TYPE: MULTI-PARAMETER WATER MONITORS FOR
DISTRIBUTION SYSTEMS
APPLICATION:
MONITORING DRINKING WATER QUALITY
TECHNOLOGY NAME: TitraSip™ SA
COMPANY: Man-Tech Associates Inc.
ADDRESS:
WEB SITE:
E-MAIL:
600 Main Street
Tonawanda, New York 14150
www.mantech-inc.com
rmenegotto @ mantech-inc.com
PHONE: 519-763-2145
FAX: 519-763-9995
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 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, financing, permitting, purchase, and use of environmental technologies. Information and ETV
documents are available at www.epa.gov/etv.
ETV works in partnership with recognized standards and testing organizations, with stakeholder groups
(consisting of buyers, vendor organizations, and permitters), and with 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 pre-
paring peer-reviewed reports. All evaluations are conducted in accordance with rigorous quality assurance (QA)
protocols to ensure that data of known and adequate quality are generated and that the results are defensible.
The Advanced Monitoring Systems (AMS) Center, one of six technology areas under ETV, is operated by Battelle
in cooperation with EPA's National Exposure Research Laboratory. The AMS Center evaluated the performance
of the Man-Tech Associates Inc. TitraSip™ SA (Stand-Alone) System in continuously measuring total chlorine,
temperature, conductivity, pH, total alkalinity, and turbidity in drinking water. This verification statement provides
a summary of the test results.
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VERIFICATION TEST DESCRIPTION
The performance of the TitraSip™ was assessed in terms of its accuracy, response to injected contaminants, inter-
unit reproducibility, ease of use, and data acquisition. The verification test was conducted between August 9 and
October 28, 2004, and consisted of three stages, each designed to evaluate a particular performance characteristic
of the TitraSip™. All three stages of the test were conducted using a recirculating pipe loop at the U.S. EPA's Test
and Evaluation Facility in Cincinnati, Ohio.
In the first stage of this verification test, the accuracy of the measurements made by the TitraSip™ units was
evaluated during nine, 4-hour periods of stable water quality conditions by comparing each TitraSip™ unit
measurement to a grab sample result generated each hour using a standard laboratory reference method and then
calculating the percent difference (%D). The second stage of the verification test involved evaluating the response
of the TitraSip™ units to changes in water quality parameters by injecting contaminants (nicotine, arsenic trioxide,
and aldicarb) into the pipe loop. Two injections of three contaminants were made into the recirculating pipe loop
containing finished Cincinnati drinking water. The response of each water quality parameter, whether it was an
increase, decrease, or no change, was documented and is reported here. In the first phase of Stage 3 of the
verification test, the performance of the TitraSip™ units was evaluated during 52 days of continuous operation,
throughout which references samples were collected once daily. The final phase of Stage 3 (which immediately
followed the first phase of Stage 3 and lasted approximately one week) consisted of a two-step evaluation of the
TitraSip™ performance to determine whether this length of operation would negatively impact the results from the
TitraSip™. First, as during Stage 1, a reference grab sample was collected every hour during a 4-hour analysis
period and analyzed using the standard reference methods. Again, this was done to define a formal time period of
stable water quality conditions over which the accuracy of the TitraSip™ could be evaluated. Second, to evaluate
the response of the TitraSip™ to contaminant injection after the extended deployment, the duplicate injection of
aldicarb, which was also included in the Stage 2 testing, was repeated. In addition, a pure E. coli culture, including
the E. coli and the growth medium, was included as a second injected contaminant during Stage 3. Inter-unit
reproducibility was assessed by comparing the results of two identical units operating simultaneously. Ease of use
was documented by technicians who operated and maintained the units, as well as the Battelle Verification Test
Coordinator.
QA oversight of verification testing was provided by Battelle and EPA. Battelle QA staff conducted a technical
systems audit, a performance evaluation audit, and a data quality audit of 10% of the test data.
This verification statement, the full report on which it is based, and the test/QA plan for this verification test are all
available at www.epa.gov/etv/centers/centerl.html.
TECHNOLOGY DESCRIPTION
The following description of the TitraSip™ was provided by the vendor and does not represent verified
information.
The TitraSip™ is designed for multi-parameter water quality testing. The system used for this verification test
analyzed pH (following EPA Method 150.1, including calibration buffers with pHs of 4, 7, and 10), conductivity
(following Standard Method [SM] 2510, which used a 1,413 microSiemens per centimeter standard for
calibration), total alkalinity (following SM 2320B), total chlorine (following SM 4500-C1 B, with a potentiometric
rather than a color, endpoint), temperature (following EPA Method 170.1), and turbidity (following SM 2130B,
including calibration solutions of 0, 10, and 100 nephelometric turbidity unit polymer standards). Additional water
quality parameters and modules (i.e., autosampler) maybe added. TitraSip™ collects a sample from a free-flowing
source (e.g., overfill cup) into the TitraSip™ Analysis Vessel and automatically completes analysis cycles at set
time intervals (in this case, once every 30 minutes) to complete the analysis for all six water quality parameters
without user intervention. The system includes a personal computer, software, interface, burets, turbidity module,
pump/valve system for adding calibrants and standards, electrodes, overfill sample cup, and TitraSip™ Analysis
Vessel. The system used for this verification test was positioned on a table top equipped with shelving for the
sampling and analysis equipment. The total system was 30 inches high and 36 inches wide, excluding the personal
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computer. Data are automatically collected at the conclusion of each cycle of sample analysis. The PC-Titrate
software controls all aspects of TitraSip™ operation. Data may be viewed directly on the personal computer as
they are acquired or they may be exported as a database or spreadsheet file. The cost of the TitraSip™ used for the
verification test was approximately $30,000. In addition, the calibration reagents cost approximately $220 per
month, preventive maintenance costs approximately $2,797 (parts only) per year, and electrode replacement costs
approximately $1,220 per year, assuming that new electrodes are needed every six months.
VERIFICATION OF PERFORMANCE
Evaluation Parameter
Stage 1—
Accuracy
Stage 2 —
Response to
Injected
Contaminants
Stage 3—
Accuracy During
Extended
Deployment
Stage 3—
Accuracy After
Extended
Deployment
Stage 3—
Response to
Injected
Contaminants
Injection
Summary
Inter-unit
Reproducibility
(Unit 2 vs. Unit 1)
Ease of Use and
Data Acquisition
Units 1 and 2, range
of %D (median)
Nicotine
Arsenic
trioxide
Aldicarb
Reference
TitraSip™
Reference
TitraSip™
Reference
TitraSip™
Units 1 and 2, range
of %D (median)
Unit 1, %D
Unit 2, %D
E. coli
Aldicarb
Reference
TitraSip™
Reference
TitraSip™
Total
Chlorine
-13.2 to
20.6 (7.5)
-
-
-
-
-
-
-18.0 to
30.0 (2.7)
1.0
0.0
-
-
-
-
Tem-
perature
-9.1 to
52.5 (-0.04)
NC
NC
NC
NC
NC
NC
-15.7 to
3.7 (-3.1)
-2.2
-1.9
NC
NC
NC
NC
Conductivity
37.9 to
94.3 (57.5)(a)
NC
NC
+
+(0
NC
NC
-2.8 to
5.2 (0.7)
0.3
1.1
+
+
NC
NC
pH
-2.2 to
5.4 (0.6)
NC
NC
+
+
NC
NC
-4.4 to
0.7 (-1.1)
-1.0
-2.1
-
-
-
-
Total
Alkalinity
3.2 to
30.4(11.5)
NC
NC
+
+
NC
NC
-16.5 to
14.4 (5.7)
-0.4
4.5
+
+
-
-
Turbidity
-65.2 to
0.6 (-45.2)
(b)
(b)
(b)
(b)
(b)
(b)
-96.7 to 155.3
(-37.3)
35.3
41.2
+
(c)
+
(c)
For a reason that is not clear, aldicarb and total alkalinity altered the pH, as measured by the reference
method, during the Stage 3 injections, but not during the Stage 2 injections.
Slope (intercept)
r2
p-value
1.06(0.03)
0.958
0.481
1.06 (-1.22)
0.942
0.915
1.16 (-38.1)
0.896
0.110
0.94 (0.545)
0.981
0.851
0.79(18.1)
0.873
0.149
0.67 (0.104)
0.683
0.449
All sensors generated results that were similar and repeatable between the units.
The TitraSip™ units required daily calibration, which involved operator intervention. Initially, the sample
cell on Unit 1 did not drain completely between pH calibration solutions, but once the drain problem was
resolved, both units functioned properly. Monitor results were recorded once every 30 minutes, which is
the maxiumum data collection frequency.
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Original signed by Gregory A. Mack 10/17/05 Original signed by Andrew P. Avel 1/17/06
Gregory A. Mack Date Andrew P. Avel Date
Assistant Division Manager Acting Director
Energy, Transportation, and Environment Division National Homeland Security Research Center
Battelle U.S. Environmental Protection Agency
NOTICE: ETV verifications are based on an evaluation of technology performance under specific, predetermined
criteria and the appropriate quality assurance procedures. EPA and Battelle 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 commercial product names does not imply endorsement.
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October 2005
Environmental Technology Verification
Report
ETV Advanced Monitoring Systems Center
MAN-TECH ASSOCIATES INC.
TITRASIP™ SA SYSTEM
CONTINUOUS MULTI-PARAMETER
WATER QUALITY MONITOR
by
Ryan James
Amy Dindal
Zachary Willenberg
Karen Riggs
Battelle
Columbus, Ohio 43201
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Notice
The U.S. Environmental Protection Agency (EPA), through its Office of Research and
Development, has financially supported and collaborated in the extramural program described
here. This document has been peer reviewed by the Agency. Mention of trade names or
commercial products does not constitute endorsement or recommendation by the EPA for use.
11
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Foreword
The U.S. Environmental Protection Agency (EPA) is charged by Congress with protecting the
nation's air, water, and land resources. Under a mandate of national environmental laws, the
Agency strives to formulate and implement actions leading to a compatible balance between
human activities and the ability of natural systems to support and nurture life. To meet this
mandate, the EPA's Office of Research and Development provides data and science support that
can be used to solve environmental problems and to build the scientific knowledge base needed
to manage our ecological resources wisely, to understand how pollutants affect our health, and to
prevent or reduce environmental risks.
The Environmental Technology Verification (ETV) Program has been established by the EPA to
verify the performance characteristics of innovative environmental technology across all media
and to report this objective information to permitters, buyers, and users of the technology, thus
accelerating the entrance of new environmental technologies into the marketplace. Verification
organizations oversee and report verification activities based on testing and quality assurance
protocols developed with input from major stakeholders and customer groups associated with the
technology area. ETV consists of six verification centers. Information about each of these
centers can be found on the Internet at http://www.epa.gov/etv/.
Effective verifications of monitoring technologies are needed to assess environmental quality
and to supply cost and performance data to select the most appropriate technology for that
assessment. Under a cooperative agreement, Battelle has received EPA funding to plan,
coordinate, and conduct such verification tests for "Advanced Monitoring Systems for Air,
Water, and Soil" and report the results to the community at large. Information concerning this
specific environmental technology area can be found on the Internet at
http://www.epa.gov/etv/centers/centerl.html.
111
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Acknowledgments
The authors wish to acknowledge the support of all those who helped plan and conduct the
verification test, analyze the data, and prepare this verification report. We would like to thank
Roy Haught and John Hall of the U.S. Environmental Protection Agency's (EPA's) Test and
Evaluation (T&E) Facility (operated by Shaw Environmental, Inc. [Shaw]) in Cincinnati, Ohio,
for hosting the verification test. The U.S. EPA primary contract to Shaw provided significant
support in interfacing the continuous monitors with the pipe loop, as well as facilitating the
experimental plan. The T&E Facility's contribution included providing the reference analyses
and operating the pipe loop, as well as reviewing the test/quality assurance (QA) plan and this
report. In addition, we would like to thank Steve Allgeier of EPA's Office of Water, Gary
Norris and Alan Vette of the EPA National Exposure Research Laboratory, Lisa Olsen of the
U.S. Geological Survey, Matthew Steele of the City of Columbus Water Quality Assurance
Laboratory, and Ron Hunsinger of East Bay Municipal Utility District, who also reviewed the
test/QA plan and/or the report.
IV
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Contents
Page
Notice ii
Foreword iii
Acknowledgments iv
List of Abbreviations viii
1 Background 1
2 Technology Description 2
3 Test Design 4
3.1 Introduction 4
3.2 Test Stages 4
3.2.1 Stage 1, Accuracy 5
3.2.2 Stage 2, Response to Injected Contaminants 5
3.2.3 Stage 3, Extended Deployment 6
3.3 Laboratory Reference and Quality Control Samples 6
3.3.1 Reference Methods 7
3.3.2 Reference Method Quality Control Samples 7
4 Quality Assurance/Quality Control 9
4.1 Audits 9
4.1.1 Performance Evaluation Audit 9
4.1.2 Technical Systems Audit 10
4.1.3 Audit of Data Quality 10
4.2 Quality Assurance/Quality Control Reporting 10
4.3 Data Review 11
5 Statistical Methods 12
5.1 Accuracy 12
5.2 Response to Injected Contaminants 12
5.3 Inter-unit Reproducibility 13
6 Test Results 14
6.1 Accuracy 15
6.2 Response to Injected Contaminants 21
6.3 Extended Deployment 25
6.4 Accuracy and Response to Injected Contaminants After Extended Deployment ... 31
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6.5 Inter-unit Reproducibility 35
6.6 Ease of Use and Data Acquisition 36
7 Performance Summary 38
8 References 39
Figures
Figure 2-1. Man-Tech Associates Inc. TitraSip™ SA 2
Figure 6-1. Stage 2 Contaminant Injection Results for Total Chlorine 22
Figure 6-2. Stage 2 Contaminant Injection Results for pH 23
Figure 6-3. Stage 2 Contaminant Injection Results for Total Alkalinity 23
Figure 6-4. Stage 2 Contaminant Injection Results for Conductivity 24
Figure 6-5. Stage 2 Contaminant Injection Results for Turbidity 24
Figure 6-6. Extended Deployment Results for Total Chlorine 26
Figure 6-7. Extended Deployment Results for pH 26
Figure 6-8. Extended Deployment Results for Total Alkalinity 27
Figure 6-9. Extended Deployment Results for Temperature 27
Figure 6-10. Extended Deployment Results for Conductivity 28
Figure 6-11. Extended Deployment Results for Turbidity 28
Figure 6-12. Stage 3 Contaminant Injection Results for Total Chlorine 32
Figure 6-13. Stage 3 Contaminant Injection Results for Turbidity 33
Figure 6-14. Stage 3 Contaminant Injection Results for pH 34
Figure 6-15. Stage 3 Contaminant Injection Results for Total Alkalinity 34
Figure 6-16. Stage 3 Contaminant Injection Results for Conductivity 35
VI
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Tables
Table 3-1. Reference Methods 7
Table 3-2. Reference Analyses and Quality Control Samples 8
Table 4-1. Performance Evaluation Audit
and Reference Method Duplicate Analysis Results 10
Table 4-2. Summary of Data Recording Process 11
Table 6-1. Summary of Test Stages and Type of Data Presentation 14
Table 6-2a. Accuracy Evaluation Under Various Conditions—Total Chlorine 15
Table 6-2b. Accuracy Evaluation Under Various Conditions—Temperature 16
Table 6-2c. Accuracy Evaluation Under Various Conditions—Conductivity 17
Table 6-2d. Accuracy Evaluation Under Various Conditions—pH 18
Table 6-2e. Accuracy Evaluation Under Various Conditions—Total Alkalinity 19
Table 6-2f. Accuracy Evaluation Under Various Conditions—Turbidity 20
Table 6-3. Effect of Contaminant Injections Prior to Extended Deployment 22
Table 6-4. Accuracy During Extended Deployment 29
Table 6-5. Post-Extended Deployment Results 31
Table 6-6. Effect of Contaminant Injections After Extended Deployment 32
Table 6-7. Inter-unit Reproducibility Evaluation 36
vn
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List of Abbreviations
AMS Advanced Monitoring Systems
cm centimeter
°C degree centigrade
DI deionized
EPA U.S. Environmental Protection Agency
ETV Environmental Technology Verification
|iS/cm microSiemens per centimeter
mg/L milligram per liter
mV millivolt
NIST National Institute of Standards and Technology
ntu nephelometric turbidity unit
%D percent difference
PE performance evaluation
PVC polyvinyl chloride
QA quality assurance
QC quality control
QMP quality management plan
SD standard deviation
SM Standard Method
T&E Test and Evaluation
TSA technical systems audit
Vlll
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Chapter 1
Background
The U.S. Environmental Protection Agency (EPA) supports the Environmental Technology
Verification (ETV) Program to facilitate the deployment of innovative 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 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, financing, permitting, purchase, and use of environmental technologies.
ETV works in partnership with recognized testing organizations; with stakeholder groups
consisting of buyers, vendor organizations, and permitters; and with the full participation of
individual technology developers. The program evaluates the performance of innovative
technologies by developing test plans that are responsive to the needs of stakeholders,
conducting field or laboratory tests (as appropriate), collecting and analyzing data, and preparing
peer-reviewed reports. All evaluations are conducted in accordance with rigorous quality
assurance (QA) protocols to ensure that data of known and adequate quality are generated and
that the results are defensible.
The EPA's National Exposure Research Laboratory and its verification organization partner,
Battelle, operate the Advanced Monitoring Systems (AMS) Center under ETV. The AMS Center
evaluated the performance of the Man-Tech Associates Inc. TitraSip™ SA (Stand-Alone)
System water quality monitor in continuously measuring total chlorine, temperature,
conductivity, pH, total alkalinity, and turbidity in drinking water. Continuous multi-parameter
water monitors for distribution systems were identified as a priority technology verification
category through the AMS Center stakeholder process.
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Chapter 2
Technology Description
The objective of the ETV AMS Center is to verify the performance characteristics of
environmental monitoring technologies for air, water, and soil. This verification report provides
results for the verification testing of the TitraSip™ water quality monitor. Following is a
description of the TitraSip™, based on information provided by the vendor. The information
provided below was not verified in this test.
The TitraSip™ (Figure 2-1) is designed for
multi-parameter water quality testing. The
system used for this verification test
analyzed pH (following EPA Method
150.1,(1) including calibration buffers with
pHs of 4, 7, and 10), conductivity
(following Standard Method [SM] 2510,(2)
which used a 1,413 microSiemens per
centimeter [|iS/cm] standard for calibra-
tion), total alkalinity (following SM
2320B),(3) total chlorine (following SM
4500-C1 B,(4) with a potentiometric rather
than a color, endpoint), temperature
(following EPA Method 170.1),(5) and
turbidity (following SM 2130B,(6) including
calibration solutions of 0, 10, and
Figure 2-1. Man-Tech Associates Inc. TitraSip™
SA
100 nephelometric turbidity unit [ntu] polymer standards). Additional water quality parameters
and modules (i.e., autosampler) may be added.
The TitraSip™ collects a sample from a free-flowing source (e.g., overfill cup) into the
TitraSip™ Analysis Vessel and automatically completes analysis cycles at set time intervals (in
this case, once every 30 minutes to complete the analysis of all six water quality parameters).
Once the analysis is initiated, no user intervention is required. The system includes a personal
computer, software, interface, burets, turbidity module, pump/valve system for adding calibrants
and standards, electrodes, overfill sample cup, and TitraSip™ Analysis Vessel. The system used
for this verification test was positioned on a table top equipped with shelving for the sampling
and analysis equipment. The total system was 30 inches high and 36 inches wide, excluding the
personal computer. Data are automatically collected at the conclusion of each cycle of sample
analysis. The PC-Titrate software controls all aspects of TitraSip™ operation. Data maybe
viewed directly on the personal computer as they are acquired or they may be exported as a
database or spreadsheet file. The cost of the TitraSip™ used for the verification test was
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approximately $30,000. In addition, the calibration reagents cost approximately $220 per month,
preventive maintenance costs approximately $2,797 (parts only) per year, and electrode
replacement costs approximately $1,220 per year, assuming that new electrodes are needed
every six months.
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Chapter 3
Test Design
3.1 Introduction
The multi-parameter water monitors tested consisted of instrument packages that connect to or
are inserted in distribution system pipes for continuous monitoring. Also included in this
technology category were technologies that can be programmed to automatically sample and
analyze distribution system water at regular intervals. The minimum requirement for
participation in this verification test was that the water monitors were able to measure residual
chlorine, as well as at least one other water quality parameter. Residual chlorine is a particularly
important water quality parameter because changes in its concentration can indicate the presence
of contamination within a distribution system, and chlorination is a very common form of water
treatment used by water utilities in the United States.
This verification test was conducted according to procedures specified in the Test/QA Plan for
Verification of Multi-Parameter Water Monitors for Distribution Systems^ and assessed the
performance of the TitraSip™ units for monitoring pH, conductivity, total chlorine, total
alkalinity, turbidity, and temperature in terms of the following:
• Accuracy
• Response to injected contaminants
• Inter-unit reproducibility
• Ease of use and data acquisition.
Accuracy was quantitatively evaluated by comparing the results generated by two TitraSip™
units to results generated by a standard laboratory reference method. Response to injected
contaminants was evaluated qualitatively by observing whether the measured water quality
parameters were affected by the injection of several contaminants. Inter-unit reproducibility was
assessed by comparing the results of two identical TitraSip™ units operating simultaneously.
Ease of use was documented by technicians who operated and maintained the units, as well as
the Battelle Verification Test Coordinator.
3.2 Test Stages
This verification test was conducted between August 9 and October 28, 2004, and consisted of
three stages, each designed to evaluate a particular performance characteristic of the TitraSip™
units. All three stages of the test were conducted using a recirculating pipe loop at the U.S.
EPA's Test and Evaluation (T&E) Facility in Cincinnati, Ohio. The recirculating pipe loop
consisted of ductile iron pipe, 6 inches in diameter and 100 feet long, which contained
approximately 240 gallons of Cincinnati drinking water with a flow rate of approximately
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1 foot/second. The water within the pipe loop had a residence time of approximately 24 hours.
Water from the pipe loop was plumbed to the two TitraSip™ units by a section of 2-inch
polyvinyl chloride (PVC) pipe in series with a shut-off valve with a ribbed nozzle that was
connected to the TitraSip™ overfill cup with a 36-foot [1/4-inch internal diameter] PVC hose
and a hose clamp. Reference samples of approximately 1 liter (enough volume to perform all the
required analyses) to be analyzed by each standard laboratory reference method were collected
from the reference sample collection valve on the PVC pipe leading to them. The reference
sample collection valve was approximately 2 feet from the origin of the PVC valve leading to
the TitraSip™.
3.2.1 Stage 1, Accuracy
During the first stage of this verification test, the accuracy of the measurements made by both
TitraSip™ units was evaluated by comparing the results from each unit to the result generated by
a standard laboratory reference method. Stage 1 testing simulated the characteristics of a variety
of water quality conditions by changing two variables: pH and temperature. Using nine sets of
pH and temperature conditions, this evaluation consisted of separate four-hour testing periods of
continuous analysis, with reference method sampling and analysis every hour. Four sets of
conditions involved varying only the pH by injecting the pipe loop with a steady stream of
sodium bisulfate. Those sets consisted of pHs of approximately 7, 8, and 9 pH units (ambient pH
at the T&E Facility was between 8 and 9) and a temperature between 21 and 23 degrees
centigrade (°C) (T&E Facility ambient during time of testing). Two other sets of conditions
included changing the water temperature to between 12 and 14°C and testing at pHs of
approximately 7 and 8; and two sets at approximately these pHs, but at a temperature of
approximately 27°C. One set (Set 2) was repeated as Set 3. The pipe loop ambient conditions
were analyzed at the start and end of this stage. Prior to each testing period with unique
conditions, the water in the pipe loop was allowed to equilibrate until the pH and temperature
were at the desired level, as determined by the standard reference methods. This equilibration
step took approximately 12 hours from the time the sodium bisulfate was added (to decrease pH)
or the temperature was adjusted.
3.2.2 Stage 2, Response to Injected Contaminants
The second stage of the verification test involved evaluating the response of the TitraSip™ units
to changes in water quality parameters by injecting contaminants into the pipe loop. Two
injections of three contaminants were made into the recirculating pipe loop containing finished
Cincinnati drinking water. Each injection was made over a period of approximately 15 seconds
by connecting the injection tank to the pipe loop's recirculating pump. The three contaminants
were nicotine, arsenic trioxide (adjusted to pH 12 to get it into solution), and aldicarb. With the
exception of the first nicotine injection, each of these contaminants was dissolved in approxi-
mately 5 gallons of pipe loop water that had been dechlorinated using granular carbon filtration
to prevent degradation of the contaminant prior to injection. Upon injection, concentrations of
these contaminants within the pipe loop were approximately 10 milligrams per liter (mg/L). For
the first nicotine injection, however, not enough nicotine to attain this concentration was
available so the available nicotine was dissolved into 2 gallons of the dechlorinated pipe loop
water and injected. The resulting nicotine concentration in the pipe loop was approximately
6 mg/L. Because the qualitative change in water quality parameters was similar for both nicotine
5
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injections despite the concentration difference, it was not necessary to repeat the 10 mg/L
injection of nicotine. For all three sets of injections, a reference sample was collected prior to the
injection and again at 3, 15, and 60 minutes after the injection. The difference between reference
method results occurring before and then again after each injection indicated the directional
change in water quality caused by the injected contaminant. For each injected contaminant, the
results from the TitraSip™ units were evaluated based on how well their directional change
matched that of the reference method result. After each injection, the pipe loop was allowed to
re-equilibrate for at least 12 hours so that each TitraSip™ unit returned to a steady baseline.
Injected contaminants were obtained from Sigma-Aldrich (St. Louis, Missouri) or ChemService
(West Chester, Pennsylvania) and were accompanied by a certificate of analysis provided by the
supplier. Battelle QA staff audited the gravimetric preparation of these solutions.
3.2.3 Stage 3, Extended Deployment
In the first phase of Stage 3 of the verification test, the performance of the TitraSip™ units was
evaluated during 52 days of continuous operation. In Section 6.6, the level of maintenance
required for the TitraSip™ throughout the verification test is discussed. To track the
performance of the TitraSip™ with respect to the reference results, reference samples were
collected and analyzed for the selected parameters at least once per day (excluding weekends
and holidays) for the duration of Stage 3. All continuously measured data were graphed, along
with the results from the reference measurements, to provide a qualitative evaluation of the data.
Throughout the duration of the extended deployment, the average percent difference (%D), as
defined in Section 5.1, between the results from the TitraSip™ units and those from the
reference methods was evaluated.
The final phase of Stage 3 (which immediately followed the first phase of Stage 3 and lasted
approximately one week) consisted of a two-step evaluation of the TitraSip™ unit performance
after the 52-day extended deployment to determine whether this length of operation would
negatively affect the results from the TitraSip™. First, while the TitraSip™ units were
continuously operating (i.e., completing an analysis cycle approximately once every 30 minutes),
a reference sample was collected every hour during a 4-hour analysis period and analyzed using
the standard reference methods. This was done to define a formal time period of stable water
quality conditions for the accuracy of the TitraSip™ to be evaluated. Second, to evaluate the
response of the TitraSip™ to contaminant injection after the extended deployment, the duplicate
injection of aldicarb, which was also included in the Stage 2 testing, was repeated. In addition, a
pure E. coli culture, including the E. coli and the growth medium, was included as a second
injected contaminant during Stage 3. E. coli was intended as an injected contaminant during
Stage 2, but was not available until later in the test. During this contaminant injection component
of Stage 3, reference samples were collected as they were during Stage 2.
3.3 Laboratory Reference and Quality Control Samples
The TitraSip™ units were evaluated by comparing their results with laboratory reference
measurements. The following sections provide an overview of the applicable procedures,
analyses, and methods.
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3.3.1 Reference Methods
To eliminate the possibility of using stagnant water residing in the reference sample collection
valve (dead volume) as the reference samples, the first step in the reference sample collection
procedure included collecting and discarding approximately 1 L of water, which was estimated
to be approximately 10 times the dead volume of a reference sample collector valve. Then, from
the same valve, approximately 1 L of water was collected in a glass beaker and carried directly
to a technician, who immediately began the reference analyses. All the analyses were performed
within minutes of sample collection. The standard laboratory methods used for the reference
analyses are shown in Table 3-1. Also included in the table are method detection limits and
quality control (QC) measurement differences. Battelle technical staff collected the reference
samples, and technical staff at the T&E Facility performed the analyses. The T&E Facility
provided calibrated instrumentation, performed all method QA/QC, and provided calibration
records for all instrumentation. The T&E Facility provided reference sample results immediately
upon the analysis of the reference samples (within one day).
Table 3-1. Reference Methods
Parameter
Method
Reference Instruments
Acceptable
Method Differences for QC
Detection Limit Measurements
pH EPA 150.1(1)
Conductivity SM 2510(2)
Total EPA310.1(8)
alkalinity
Total SM 4500-G(9)
chlorine
Temperature EPA 170.1(5)
Turbidity SM2130B(6)
Corning 320 pH meter
YSI556 multi-parameter
water monitor
Corning 320 pH meter
Hach 2400 portable
spectrophotometer
YSI 556 multi-parameter
water monitor
Hach 21 OOP turbidimeter
NA
2 |iS/cm
20mg/L
0.01 mg/L as C12
NA
0.067 ntu
±0.3 pH units
±25 %D
±25 %D
±25 %D
±1°C
±25 %D
NA = not applicable.
3.3.2 Reference Method Quality Control Samples
As shown in Table 3-2, duplicate reference samples were collected and analyzed once daily
during Stages 1 and 2 and weekly during Stage 3. Also, laboratory blanks consisting of
American Society for Testing and Materials Type n deionized (DI) water were analyzed with the
same frequency. Reference analyses of these blank samples were most important for total
chlorine because it was the only parameter that needed confirmation of the lack of
contamination. For the other parameters, the performance evaluation (PE) audit confirmed the
accuracy of the method and the absence of contamination. Duplicate measurements had to be
within the acceptable differences provided in Table 3-1.
-------
Table 3-2. Reference Analyses and Quality Control Samples
Sampling
Stage Periods (length)
Reference
Sample
Frequency
Reference
Samples
per Period
QC Samples per Total QC
Period Samples
1: Accuracy
9 (4 hours)
One at start, one
every hour
thereafter
One duplicate and
5 one DI water blank
daily
18
0 „ , One pre-in ection;
2: Response to ^ 0 , i ,
• • . , .•, ..... one at 3,15, and
injected 6 (one injection) n .
J J 60 minutes post-
injection
contaminants
One duplicate and
one DI water blank
daily
3: Post-extended
deployment 1 (4 hours) Same as Stage 1
accuracy
Same as Stage 1
12
3: Extended
deployment
1 (52 days)
Once each
weekday
37
One duplicate and
one DI water blank
each week
16
3: Response to
injected 4 (one injection) Same as Stage 2
contaminants
Same as Stage 2
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Chapter 4
Quality Assurance/Quality Control
QA/QC procedures were performed in accordance with the test/QA plan(7) for this verification
test and quality management plan (QMP) for the AMS Center.(10)
4.1 Audits
4.1.1 Performance Evaluation Audit
A PE audit was conducted to assess the quality of the reference measurements made in this
verification test. With the exception of temperature, each type of reference measurement was
compared with a National Institute of Standards and Technology (NIST)-traceable standard
reference water sample. The standard reference water samples had certified values of each water
quality parameter that were unknown to the analyst. These samples were analyzed in the same
manner as the rest of the reference analyses to independently confirm the accuracy of the
reference measurements. The temperature PE audit was performed by comparing two
independent thermometer results. As Table 4-1 shows, all PE audit results were within the
acceptable differences provided in Table 3-1. The percent difference (%D) was calculated using
the following equation:
%D= R~ N xlOO%
where CR is the reference method result, and CN is the NIST value for each respective water
quality parameter (or, for temperature, data from the second thermometer). Other QC data
collected during this verification test were reference method duplicate analysis results, which are
also shown in Table 4-1. With the exception of one duplicate measure of turbidity, all six
parameters were always within the differences defined in Table 3-1. Because pH units are
measured on a logarithmic, rather than a linear, scale, and the measurement of temperature is
extremely precise, the quality control metrics for those two parameters were the absolute units
rather than the percent difference. No corrective action was taken for the one turbidity measure-
ment (55.2%) that was outside the acceptable difference. If this outlier is removed, the upper
range of percent difference was 18.2%, and the average absolute value of differences was 5.4%.
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Table 4-1. Performance Evaluation Audit and Reference Method Duplicate Analysis
Results
Parameter
pH (pH unit)
Conductivity (|iS/cm)
Total chlorine (mg/L)
Temperature (°C)
Total alkalinity (mg/L)
Turbidity (ntu)
NIST Standard
Value
9.26
1,920
4.19
23.80(a)
358
20
PE Audit
Reference
Method
Result
9.18
1,706
3.62
23.80
360
22.3
Difference
-0.08 pH unit
-11.1%
-13.6%
0.00°C
0.6%
11.5%
Duplicate Analysis
Average of
Absolute Values Range of
of Difference Difference
0.04 pH unit 0.0 to 0. 13 pH unit
0.25% -1.9 to 0.7%
2.62% -7.3 to 2.1%
0.02°C -0.18to0.29°C
0.02% -5.6 to 2.9%
7.49% -8.7 to 55. 2%
Since a standard for temperature does not exist, the PE audit for temperature was performed by comparing the
results with those from a second thermometer.
4.1.2 Technical Systems Audit
The Battelle Quality Manager performed a technical systems audit (TSA) to ensure that the
verification test was performed in accordance with the test/QA plan,(7) AMS Center QMP,(8)
published reference methods, and any standard operating procedures used by the T&E Facility.
The TSA noted no adverse findings. A TSA report was prepared, and a copy was distributed to
the EPA AMS Center Quality Manager.
4.1.3 Audit of Data Quality
At least 10% of the data acquired during the verification test was audited. Battelle's Quality
Manager traced the data from the initial acquisition, through reduction and statistical analysis, to
final reporting, to ensure the integrity of the reported results. All calculations performed on the
data undergoing the audit were checked.
4.2 Quality Assurance/Quality Control Reporting
Each assessment and audit was documented in accordance with Sections 3.3.4 of the QMP for
the ETV AMS Center.(8) Once the assessment report was prepared, the Battelle Verification Test
Coordinator ensured that a response was provided for each adverse finding or potential problem
and implemented any necessary follow-up corrective action. The Battelle Quality Manager
ensured that follow-up corrective action was taken. The results of the TSA were sent to the EPA.
10
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4.3 Data Review
Records generated in the verification test were reviewed before these records were used to
calculate, evaluate, or report verification results. Table 4-2 summarizes the types of data
recorded. The review was performed by a technical staff member involved in the verification
test, but not the staff member who originally generated the record.
Table 4-2. Summary of Data Recording Process
Data to Be
Recorded
Dates, times, and
details of test
events
Calibration
information
(TitraSip™ units
and reference
methods)
TitraSip™ units
results
Reference method
procedures
Where Recorded
ETV data sheets
and testing
notebook
ETV data sheets
and testing
notebook
Recorded
electronically by
each unit
ETV laboratory
record books or
data recording
forms
How Often
Recorded
Start/end of test and
at each change of a
test parameter
Upon each
calibration
Recorded as
measurement cycles
were completed
Throughout sample
analysis process
By
Whom
Battelle
and T&E
Facility
Battelle
and T&E
Facility
Battelle
T&E
Facility
Disposition of
Data
Used to
organize/check test
results; manually
incorporated in
data spreadsheets
as necessary
Manually
incorporated in
data spreadsheets
as necessary
Excel files
Transferred to
spreadsheets or
laboratory record
book
11
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Chapter 5
Statistical Methods
The statistical methods presented in this chapter were used to verify the TitraSip™ units'
accuracy, response to injected contaminants, and inter-unit reproducibility.
5.1 Accuracy
Throughout this verification test, results from the TitraSip™ units were compared to the results
obtained from analysis of a grab sample by the reference methods. During Stage 1, the percent
difference (%D) between these two results was calculated using the following equation:
C - C
%D= m *
where CR is the result determined by the reference method and Cm is the result from a TitraSip™
unit; the TitraSip™ unit results were recorded approximately every 30 minutes, whereas
collecting the reference samples took only a few seconds. Therefore, CR was the reference
measurement recorded closest to the time the TitraSip™ sample was collected. Water quality
stability, as well as the stability of each sensor, was evaluated during the four-hour time period
when reference samples were analyzed every hour for each of the parameters. Ideally, if the
result from a TitraSip™ unit and a reference method measurement were the same, there would
be a percent difference of zero. It should be noted that the formula for percent difference is
sensitive to reference results that are small in magnitude. For example, if the reference turbidity
is 0.1 ntu, and the online instrument reads 0.2, the percent difference is 100%. Alternatively, if
the reference turbidity is 1.0 ntu, and the online instrument reads 1.1, the percent difference is
only 10%. During Stages 2 and 3, the TitraSip™ data, graphed with the reference method
results, were visually examined to evaluate the response of the TitraSip™ unit to the injection of
contaminants and their stability over an extended deployment. During the accuracy and
contaminant injection components of Stage 3, the data were evaluated as they were for Stages 1
and 2, respectively.
5.2 Response to Injected Contaminants
To evaluate the response (i.e., the increase or decrease of water quality parameter measured by
the TitraSip™ units) to contaminant injections, the pre- and post-injection reference samples
were graphed as individual data points, along with the continuous measurements. The reference
12
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results showed the effect of each injection on the chemistry of the water in the pipe loop, and the
continuous results from the TitraSip™ unit highlighted its response to such changes.
5.3 Inter-unit Reproducibility
The results obtained from two identical TitraSip™ units were compared to assess inter-unit
reproducibility. Each time a reference sample was collected and analyzed (approximately
127 times throughout this verification test), the results from each TitraSip™ unit were compared
to evaluate whether the two TitraSip™ units were generating similar results. This was done in
two ways. First, the results from one unit were graphed against the results of the other unit. In
this evaluation, a slope of unity and a coefficient of determination (r2) of 1.00 would indicate
ideal inter-unit reproducibility. Slopes above 1.0 may indicate a high bias from Unit 2 (graphed
on the y-axis) or a low bias for Unit 1 with respect to each other. Similarly, slopes below 1.0
may indicate a low bias for Unit 2 or a high bias for Unit 1, again with respect to each other.
Second, the data from each unit were included in a paired t-test, with the assumption that the
data from each unit had equal variances. The t-test calculated the probability of obtaining the
subject results from the two units if there was no significant difference between their results.
Therefore, probability values (p-values) of less than 0.05 indicated a significant difference
between the two units. In addition, the results from both units were graphed together for the
Stages 2 and 3 results, allowing a visual comparison.
13
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Chapter 6
Test Results
As mentioned previously, this verification test was conducted in three stages that focused on
three different aspects of multi-parameter water monitors for distribution systems. The three
stages are summarized in Table 6-1. The first stage consisted of an evaluation (with varied pHs
and temperatures) of the accuracy of each TitraSip™ unit sensor: total chlorine, temperature,
conductivity, pH, total alkalinity, and turbidity. The second stage of the verification test
consisted of an evaluation of the response of the TitraSip™ units to the injection of several
contaminants into the pipe loop. The third stage consisted of deploying the TitraSip™ unit for
52 consecutive days with minimal intervention for maintenance. In addition, contaminant
injections were performed at the close of Stage 3 to confirm that the TitraSip™ units were still
responsive to contaminant injection after the extended deployment. Two TitraSip™ units were
tested to evaluate inter-unit reproducibility. In addition, required maintenance and operational
characteristics were documented throughout the verification test. This chapter provides the
results of the three testing stages, the inter-unit reproducibility data, and ease of use information.
Table 6-1. Summary of Test Stages and Type of Data Presentation
Stage Summary
Data Presentation
1 Accuracy when pH and temperature
were varied
Table of percent differences between
TitraSip™ units and reference
measurements
Response to contaminant injection
Graphs of TitraSip™ unit measurements and
reference measurements, table showing the
effect of injections on both reference and
TitraSip™ measurements
Extended deployment with minimal
maintenance along with post-extended
deployment accuracy and response to
contaminant injections
Graphs of TitraSip™ unit measurements
with reference measurements, table showing
average percent differences throughout
extended deployment, table showing the
effect of injections on both reference and
TitraSip™ measurements
14
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6.1 Accuracy
Tables 6-2a-f list the data from the accuracy evaluation performed during the first stage of the
verification test. During four-hour periods, the water quality conditions were held stable, and
reference samples were collected and analyzed five times, once at the start of the designated test
period and four times at one-hour increments thereafter. In evaluating accuracy in each four-hour
period, measurements from each reference sample were compared with the TitraSip™
measurement taken closest to the time of the reference sample collection and analysis. For each
unit, this approach resulted in five paired TitraSip™ and reference results for each of the nine
sets of water conditions used to simulate pH and temperature variations at a water utility. The
average and standard deviations of these five results are shown in the tables below, as well as the
percent difference between the average results from both TitraSip™ units and the average of the
reference results.
Table 6-2a. Accuracy Evaluation Under Various Conditions—Total Chlorine
Set
1
2
3
4
5
6
7
8
9
Reference
Unitl
Average (SD) Average (SD)
Conditions [mg/L] [mg/L]
ambient pH,
ambient temperature
decreased pH, ambient
temperature
decreased pH, ambient
temperature
decreased pH, ambient
temperature
ambient pH, decreased
temperature
decreased pH, decreased
temperature
ambient pH, increased
temperature
decreased pH, increased
temperature
ambient pH, ambient
temperature
0.97 (0.07)
0.86 (0.02)
0.73 (0.01)
0.38 (0.03)
0.51 (0.08)
1.56(0.05)
0.69 (0.01)
0.65 (0.07)
0.98 (0.02)
0.96 (0.03)
0.88 (0.04)
0.82 (0.04)
0.44 (0.03)
0.56 (0.04)
1.59(0.06)
0.69 (0.06)
0.63 (0.02)
0.94 (0.02)
Unit 2
Average (SD)
% D [mg/L]
-1.0 1.17(0.08)
2.3 0.93 (0.13)
12.3 0.81 (0.06)
15.8 0.33 (0.06)
9.8 0.58 (0.02)
1.9 1.78(0.03)
0.0 0.74(a)(0.03)
-3.1 0.70(0.06)
-4.1 1.05 (0.09)
%D
20.6
8.1
11.0
-13.2
13.7
14.1
7.2
7.7
7.1
One result was 3.07 mg/L. This was clearly an outlier due to air bubbles in the buret, so it was removed from the
calculation of the percent difference.
15
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Table 6-2b. Accuracy Evaluation Under Various Conditions—Temperature
Set
1
2
3
4
5
6
7
8
9
Reference
Unitl
Average (SD) Average (SD)
Conditions [°C] [°C]
ambient pH,
ambient temperature
decreased pH, ambient
temperature
decreased pH, ambient
temperature
decreased pH, ambient
temperature
ambient pH, decreased
temperature(a)
decreased pH,
decreased temperature(a)
ambient pH, increased
temperature
decreased pH, increased
temperature
ambient pH, ambient
temperature
22.66 (0.33)
22.73 (0.23)
21.66(0.08)
21.93(0.15)
13.82 (0.44)
12.63 (0.26)
26.60 (0.27)
26.69 (0.23)
22.79 (0.21)
23.85 (0.99)
23.21 (0.77)
20.12(0.51)
20.31 (0.30)
21.08(0.33)
18.99 (0.90)
24.33 (0.59)
24.26 (0.99)
22.85 (0.51)
%D
5.3
2.1
-7.1
-7.4
52.5
50.4
-8.5
-9.1
0.3
Unit 2
Average (SD)
23.62(1.11)
23.64 (0.45)
20.24 (0.61)
20.37 (0.14)
18.82 (0.26)
17.88 (1.02)
24.90 (0.59)
24.82 (0.97)
22.71 (0.59)
%D
4.2
4.0
-6.6
-7.1
36.2
41.6
-6.4
-7.0
-0.4
ised percent differences were likely due to equilibration with the ambient air temperature en route to the
continuous monitor. Prior to analysis by the TitraSip™, the water had traveled through 36 feet of 1/4-inch
diameter tubing. During the decreased temperature condition, this maximized heat transfer to the water from
ambient air; and vice versa during the increased temperature condition.
16
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Table 6-2c. Accuracy Evaluation Under Various Conditions—Conductivity
(a)
Set
1
2
3
4
5
6
7
8
9
Conditions
ambient pH,
ambient temperature
decreased pH, ambient
temperature
decreased pH, ambient
temperature
decreased pH, ambient
temperature
ambient pH, decreased
temperature
decreased pH,
decreased temperature
ambient pH, increased
temperature
decreased pH, increased
temperature
ambient pH, ambient
temperature
Reference
Average (SD)
[|j,S/cm]
451 (1)
484 (10)
503 (60)
694 (12)
412(1)
501 (10)
447 (1)
529 (2)
442 (1)
Unitl
Average (SD)
[US/cm]
622 (23)
763 (40)
825 (202)
1,056(35)
593 (6)
761 (16)
656 (10)
778 (14)
644 (9)
%D
37.9
57.6
64.0
52.2
43.9
51.9
46.8
47.1
45.7
Unit 2
Average (SD)
[[iS/cm]
702 (3)
803 (22)
791 (3)
1,107(15)
729 (2)
924 (22)
851 (5)
1,028(5)
793 (3)
%D
55.7
65.9
57.3
59.5
76.9
84.4
90.4
94.3
79.4
(a) AftAr tTiic ctQaA nf tTiA A7
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Table
Set
1
2
3
4
5
6
7
8
9
6-2d. Accuracy Evaluation Under Various Conditions — pH
Conditions
ambient pH,
ambient temperature
decreased pH, ambient
temperature
decreased pH, ambient
temperature
decreased pH, ambient
temperature
ambient pH, decreased
temperature
decreased pH, decreased
temperature
ambient pH, increased
temperature
decreased pH, increased
temperature
ambient pH, ambient
temperature
Reference
Average (SD)
[pH unit]
8.76 (0.02)
7.56 (0.41)
7.17 (0.40)
6.70 (0.22)
8.18 (0.36)
7.31 (0.08)
8.12 (0.23)
7.49 (0.25)
8.56 (0.19)
Unitl
Average (SD)
[pH unit]
8.66 (0.04)
7.81 (0.10)
7.53 (0.06)
6.55 (0.06)
8.40 (0.03)
7.25 (0.08)
8.25 (0.03)
7.38 (0.04)
8.61 (0.02)
%D
-1.1
3.3
5.0
-2.2
2.7
-0.8
1.6
-1.5
0.6
Unit 2
Average (SD)
[pH unit]
8.74 (0.02)
7.87(0.10)
7.56 (0.03)
6.65 (0.07)
8.40 (0.01)
7.34 (0.09)
8.29 (0.01)
7.52 (0.02)
8.61 (0.01)
%D
-0.2
4.1
5.4
-0.7
2.7
0.4
2.1
0.4
0.6
18
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Table 6-2e. Accuracy Evaluation Under Various Conditions—Total Alkalinity
Set
Conditions
Reference
Average (SD)
[mg/L]
Unitl
Unit 2
Average (SD) Average (SD)
[mg/L] % D [mg/L] % D
1 ambient pH, 82.73(1.51)
ambient temperature
2 decreased pH, ambient 71.52(1.18)
temperature
3 decreased pH, ambient 64.56 (0.54)
temperature
4 decreased pH, ambient 39.84(2.31)
temperature
5 ambient pH, decreased 72.72(1.58)
temperature
6 decreased pH, decreased 59.84 (2.62)
temperature
7 ambient pH, increased 72.24 (0.36)
temperature
8 decreased pH, increased 60.64(0.61)
temperature
9 ambient pH, ambient 81.52(0.59)
temperature
107.88(1.60) 30.4 92.11(0.17) 11.3
73.82(0.62) 3.2 80.06(0.81) 11.9
66.86(0.21) 3.6 73.38(0.15) 13.7
41.27(2.00) 3.6 44.91(1.92) 12.7
78.74(0.16) 8.3 81.26(0.11) 11.7
64.46(2.15) 7.7 66.77(2.06) 11.6
79.54(4.09) 10.1 83.30(0.25) 15.3
64.25 (0.59) 6.0 69.06 (0.39) 13.9
86.71(0.39) 6.4 92.74(0.23)
19
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Table 6-2f. Accuracy Evaluation Under Various Conditions—Turbidity
Reference
Unit 1 Unit 2
Average (SD) Average (SD) Average (SD)
Set Conditions [ntu] [ntu] %D [ntu] %D
1 ambient pH, 1.27(0.95) 0.48(0.20) -62.2 0.53(0.06) -58.3
ambient temperature
2 decreased pH, ambient 1.14(0.40) 0.55(0.20) -51.8 0.61(0.15) -46.5
temperature
3 decreased pH, ambient 0.97(0.33) 0.70(a) (0.09) -27.8 0.54(0.10) -44.3
temperature
4 decreased pH, ambient 1.54(0.20) 1.55(0.10) 0.6 1.18(0.04) -23.4
temperature
5 ambient pH, decreased 0.89(0.41) 0.52(0.40) -41.6 0.33(0.05) -62.9
temperature
6 decreased pH, decreased 0.99(0.21) 0.55(0.05) -44.4 0.60(0.04) -39.4
temperature
7 ambient pH, increased 0.92(0.16) 0.48(0.08) -47.8 0.57(0.14) -38.0
temperature
8 decreased pH, increased 1.00(0.35) 0.54(0.09) -46.0 0.56(0.04) -44.0
temperature
9 ambient pH, ambient 0.46(0.11) 0.16(0.04) -65.2 0.19(0.06) -58.7
temperature
-------
both the TitraSip™ and the reference method used calibration solutions ranging from less than
1 ntu to 100 ntu. Because of the low turbidity in the tested water, calibration solutions more
focused on low turbidity may have improved agreement between the two measurements. In
addition, the turbidity and total chlorine had one result that was clearly outlying and, therefore,
was removed as noted on the appropriate table. After removing one outlier, the total chlorine
percent differences were all less than 21%. For total alkalinity, there was one percent difference
of 30.4%, but the rest of the sets resulted in percent differences of 15% or less. The range of
percent differences for temperature also was always less than 10%, except during decreased
temperature conditions. Because the TitraSip™ units were titrated on a 4-foot by 6-foot table,
they had to be located one floor below the reference sample collection valve. The water sample
traveled to the TitraSip™ in a tube that was approximately 36 feet from the PVC pipe connected
to the pipe loop and that had an internal diameter of 1/4 inch. Because the water was in contact
with the large surface area of the tubing, heat transfer from the ambient air was maximized, thus
increasing the temperature of the water and most likely contributing to the positive percent
differences. The temperature percent differences from the other test conditions were not as large,
probably because the difference between the ambient air and increased water temperatures was
not as great as the difference between the ambient air and decreased water temperatures.
The standard deviations of the reference and continuous measurements collected during each test
period were, with few exceptions, very small with respect to the average result. In only a few
instances was the standard deviation greater than 5% of the average result. The only exception to
this was for turbidity, which was not controlled as part of the verification test, but was dependent
on events occurring within the Cincinnati water utility. Also, small changes corresponded to
rather large relative changes because of the low turbidity of the Cincinnati water. This shows
that the water conditions during the test periods were very stable and that there was very little
variability in the sensors themselves. The results were not remarkably different among the
various sets; therefore, the TitraSip™ unit performance did not seem to be dependent on the
water conditions.
6.2 Response to Injected Contaminants
Six injections of contaminants were performed during the second stage of this verification test;
i.e., duplicate injections of nicotine, arsenic trioxide, and aldicarb. As Table 6-3 shows, only the
total chlorine measurement was visibly affected by all three contaminants. In the table, the
directional change of each reference and TitraSip™ measurement is given.
Figures 6-1 through 6-5 show the response of total chlorine, pH, alkalinity, conductivity, and
turbidity. The blue and yellow lines on the figure represent the measurements made by each
TitraSip™ unit, and the magenta data points represent the results from the laboratory reference
method. Because accuracy was the focus of the first stage of verification testing, percent
differences between the TitraSip™ units and the reference method results are not presented here;
however, the reference method results are included in these graphs to confirm that the
fluctuations in the continuous results are due to changes in water chemistry as the result of the
injected contaminants. The figure is divided with vertical lines that define the approximate time
period for each injection. Each injection time period defined on the figure is approximately
24 hours, but the times vary depending on when chlorine was added to restore the system to
21
-------
Table 6-3. Effect of Contaminant Injections Prior to Extended Deployment
Nicotine
Parameter
Total chlorine
Temperature
Conductivity
pH
Total alkalinity
Turbidity
Reference
-
NC
NC
NC
NC
(b)
TitraSip™
-
NC
NC
NC
NC
(b)
Arsenic Trioxide
Reference
-
NC
+
+
+
(b)
TitraSip™
-
NC
+(a)
+
+
(b)
Aldicarb
Reference
-
NC
NC
NC
NC
(b)
TitraSip™
-
CN
NC
NC
NC
(b)
-------
9.5-
9-
8.5-
8
7.5-
7-
6.5 -
R
Nicotine 1
if^-Nn^-y-
Nicotine 2
4
Arsenic 1
*
*
Arsenic 2
I
,1*
K.-
Aldicarb 1
&
Aidicarb 2
M
4*
Figure 6-2. Stage 2 Contaminant Injection Results for pH
100
90-
80
70-
60
B. 50
40
30-
20-
10-
0-
Nicotine 1
Nicotine 2
»_»*
Arsenic 1 Arsenic 2 Aldicart) 1
Aldicarb 2
Figure 6-3. Stage 2 Contaminant Injection Results for Total Alkalinity
23
-------
0)
y
Ł
IUUU
900 -
800
700
600
500 -
400 -
300 -
200 -
100 -
n
Nicotine 1
1
•
1
|v-v
Nicotine 2
L-
4
Arsenic 1
->*-
Arsenic 2
AM cart) 1
Alriicarb 2
Figure 6-4. Stage 2 Contaminant Injection Results for Conductivity
,\_N
Figure 6-5. Stage 2 Contaminant Injection Results for Turbidity
24
-------
pre-injection conditions. The contaminant that was injected and whether it was the first or
second replicate are shown at the top of each section of the figure. For each injection, at least
four reference sample results were collected and are included in this figure. The first occurred
within approximately one hour prior to contaminant injection during a period of stable water
quality conditions. The next three reference data points were from samples collected 3, 15, and
60 minutes after contaminant injection. For some of the injections, another reference sample was
collected the following day to show that the pipe loop system had recovered or was in the
process of recovering after the injection. This final reference data point also served as the first
reference sample collected for some of the injections, representing the stable baseline just prior
to injection. Each of the reference measurement results are shown; but, because the TitraSip™
only collected data every 30 minutes, they are not aligned perfectly with the times of their
analyses. They are aligned with the closest TitraSip™ analysis time.
Prior to the injections, the total chlorine level was between 0.9 and 1.3 mg/L and within 10% to
20% of the reference measurement. After injection, the total chlorine level, as measured by the
reference method, dropped to between 0.5 and 0.2 mg/L for nicotine and to nearly 0 mg/L for
arsenic and aldicarb. Upon the injection of nicotine, the chlorine level decreased to
approximately 0.5 mg/L. For the other four injections, the TitraSip™ units immediately dropped
to a concentration of nearly 0 mg/L, as had the laboratory reference method. After each
injection, the total chlorine level in the pipe loop system was restored to approximately
pre-injection conditions by adding sodium hypochlorite. This is shown in Figure 6-1 by the
rapidly increasing total chlorine measurements after the low point was reached.
The pH and total alkalinity were affected by the arsenic trioxide injection. The conductivity
reference measurement increased slightly upon injection of arsenic trioxide. That increase was
measured by both TitraSip™ units during the first injection, but only by Unit 2 during the
second injection. In addition, the effect of the injections on turbidity was not clear for the
reference method or for the TitraSip™. For all the injections except the second arsenic injection,
the level of turbidity measured by the reference method decreased from the time the pre-
injection reference sample was collected until the subsequent reference samples were collected
and analyzed. This suggests that 1) the contaminant injections did not increase the turbidity in
the flowing water or, 2) that the uncertainty in the reference measurements was too large to
determine whether turbidity was significantly affected. In any case, any change in turbidity due
to the injections was not clear from the TitraSip™ measurements because of this overall
uncertainty in the background turbidity measurements.
6.3 Extended Deployment
Figures 6-6 through 6-11 show the continuous measurements from both TitraSip™ units during
the 52-day extended deployment stage of the verification test. Those measurements are
represented by the blue and yellow lines, while the results of the reference samples, collected
once daily throughout this deployment, are represented by the magenta symbols. The x-axis on
each figure represents the period of time between September 1, 2004, and October 22, 2004, and
the y-axis gives the results of each water quality measurement. Data points were recorded every
30 minutes during the verification test; and, for the extended deployment figures, all data points
were depicted.
25
-------
Figure 6-6. Extended Deployment Results for Total Chlorine
S.5 -
8 -
7 -
6.5-
Event#1
Event #2
Figure 6-7. Extended Deployment Results for pH
26
-------
Duiation of Static 3 52 days
-8. Extended Deployment Results for Total Alkalinity
^.u
26 -
24 -
22 -
O
$ 20-
a
I* 18
16 -
14 -
12 -
10 -
P Event #1
y* A'VV U[\/ft
* V' ^y^:\V^>f^*J>rr-:-
' '"'""' ,;' ' \
Duration of Stage 3 52 days
— Unitl
• Reference
Unit 2
Figure 6-9. Extended Deployment Results for Temperature
27
-------
600
500
^
c
41
400 -
300 -
W
p
200
100 -
0
Figure 6-10. Extended Deployment Results for Conductivity
8
7
6
5
4
3
I
*' V *
— Unitl
* Reference
Unit 2
Figure 6-11. Extended Deployment Results for Turbidity
28
-------
The objective of this stage of the verification test was to evaluate the performance of the
TitraSip™ unit over an extended period of time with minimal intervention to simulate a situation
in which the units may be deployed at a remote location. The continuous trace was visually
evaluated to see whether any aspects of the data were noteworthy. A second, more quantitative,
evaluation was then performed to indicate the accuracy of the extended deployment measure-
ments. This evaluation, much like the accuracy evaluation conducted during the first stage of
testing, included calculating the percent differences between the average continuous measure-
ments and average reference sample results throughout the extended deployment, as well as the
standard deviation of each of those measurements. The standard deviation of the results provided
a means to evaluate the stability of the water conditions during Stage 3, as well as how the
standard deviations of the continuous measurements differed from the standard deviations of the
reference measurements. Similar relative standard deviations between the continuous and
reference measurements indicate that the variability was mostly dependent on the water
conditions and not due to systematic variability in the TitraSip™ unit results. (Note that the
reference results were only generated during business hours, so any fluctuations occurring during
off hours are not reflected in the standard deviation of the reference results. Because of this, total
chlorine, a parameter that varied at times during weekends when the supply of chlorine ran low,
might have been expected to have a larger variability than other more stable parameters.)
Table 6-4 lists the percent differences, along with the average and standard deviations of the
reference and continuous results during the extended deployment. The range and median (see the
footnote in Section 6.1 for direction on intepreting the median) percent difference for each water
quality parameter, as measured for each reference sample analyzed during the extended
deployment, are also given.
Table 6-4. Accuracy During Extended Deployment
Parameter
Total chlorine(b)
Temperature
Conductivity
PH
Reference
Average (SD)(a)
1.05(0.10)
22.81 (0.35)
352 (55)
8.73 (0.07)
Unitl
Average (SD)(a)
1.08(0.12)
21.88(1.07)
336 (58)
8.60(0.12)
%D
2.9
-4.1
1.2
-1.5
Unit 2
Average (SD)(a)
1.08(0.12)
22.01 (1.12)
335 (56)
8.62(0.10)
%D
2.9
-3.5
0.9
-1.3
Both Units %D
Range (median)
-18.0 to 30.0 (2.7)
-15.7 to 3.7 (-3.1)
-2.8 to 5.2 (0.7)
-4.4 to 0.7 (-1.1)
Total alkalinity 66.86(7.71) 68.99(8.46) 3.2 71.61(8.32) 7.1 -16.5 to 14.4 (5.7)
Turbidity 0.74(1.57) 0.42(1.09) -43.2 0.35(1.04) -52.7 -96.7 to 155.3 (-37.3)
-------
chlorine concentration, as measured by the reference method, was 1.05 ± 0.10 mg/L, while both
TitraSip™ units measured an average of 1.08 mg/L ± 0.12.
The extended deployment pH results are shown in Figure 6-7. With the exception of one
negative spike (pH Event #1 in Figure 6-7), the pH measurements from both units tracked each
other and the reference measurements fairly well early in Stage 3. Unit 2 continued tracking the
reference measurements rather well, while the Unit 1 pH measurements became extremely
variable over the next several days (pH Event #2). Man-Tech determined that, during the
calibration routine, the TitraSip™ Analysis Vessel on Unit 1 was not draining properly,
preventing calibration reagent from emptying completely from the TitraSip™ Analysis Vessel
prior to adding the next calibration reagent, thus invalidating the calibration and causing the
variable results. During a service visit, Man-Tech determined that broken glass from the
temperature probe was obstructing the drain. The temperature probe apparently broke when the
system was installed. The temperature results was not affected; but when the glass was removed,
the performance of the pH electrode became steadier; and both units tracked one another and the
reference method well. The average pH, as measured by the reference method, was 8.73 ± 0.07,
and the averages for Units 1 and 2, respectively, were 8.60 ± 0.12 and 8.62 ± 0.10. Overall,
during the extended deployment, the percent difference for the pH sensor ranged from -4.4 to
0.7, with a median of -1.1.
As shown in Figure 6-8, the total alkalinity results for both units tracked one another and the
reference results. However, there was a brief period of high variability in Unit 1 near the start
and middle of the stage (total alkalinity Events #1 and #2 in Figure 6-8), which subsided quickly
Because pH is the critical measurement in determining alkalinity, this variability probably
corresponded with the aforementioned pH electrode calibration problem. One other aspect of the
alkalinity data to note is that the Unit 2 results were consistently biased slightly high with respect
to Unit 1.
The temperature results for Units 1 and 2 varied regularly because the test was conducted in a
facility where the water temperature was heavily affected by the outdoor temperature; therefore,
the water temperature changed as a function of the high and low temperatures for the day. As
shown in Figure 6-9, as Stage 3 progressed, the temperature results from both units became
slightly lower with respect to the reference results (temperature Event #1 in Figure 6-9) probably
because the Man-Tech units were located near an outside door that was often opened, while the
reference measurement was performed on the second floor of the T&E Facility, where the
ambient air temperature was not affected as much by the outdoor temperature.
As shown in Figure 6-10, the TitraSip™ units had a few low conductivity spikes (conductivity
Event #1 in Figure 6-10), but the conductivity measurements from both units tracked the
reference measurements very well. Figure 6-11 shows that, in the early part of Stage 3, the
turbidity measurements were generally lower than the reference method measurement; however,
this improved during the second half of the stage. The reason for this improvement was not
apparent. One other item of note on Figure 6-11 is the high turbidity event about one-third of the
way through the stage (turbidity Event #1 in Figure 6-11). The event was caused by an unknown
occurrence in the Cincinnati water system. The reference result matched the TitraSip™ result
rather well during that event.
30
-------
6.4 Accuracy and Response to Injected Contaminants After Extended Deployment
After the 52-day deployment of the TitraSip™ units, their performance was evaluated during a
4-hour period of ambient pH and temperature during which reference samples were collected
hourly. The results of this evaluation are given in Table 6-5. With the exception of the
conductivity measurement, the percent differences determined after the extended deployment for
total chlorine, total alkalinity, turbidity, temperature, and pH were not considerably different
from those determined during Stage 1. Because the TitraSip™ units were routinely calibrated, it
was not expected that the extended deployment would negatively affect their results. However,
as discussed in Section 6.1, Man-Tech introduced a new calibration procedure for the
conductivity meter after the Stage 1 testing. Prior to using the new procedure, the difference
between the TitraSip™ and the reference method was at least 40%; afterwards, it improved to
less than 5%.
Table 6-5. Post-Extended Deployment Results
Parameter
Total chlorine
Temperature
Conductivity
PH
Total alkalinity
Turbidity
Reference
Average (SD)(a)
1.03 (0.03)
22.66(0.16)
356(1)
8.59 (0.01)
77 (0.83)
0.17(0.02)
Unitl
Average (SD)(a)
1.04(0.01)
22.16(0.09)
357 (2)
8.50(0.01)
76.73 (0.12)
0.23(0.11)
%D
1.0
-2.2
0.3
-1.0
-0.4
35.3
Unit 2
Average (SD)(a)
1.03 (0.03)
22.23 (0.06)
360 (2)
8.41 (0.09)
80.49 (0.66)
0.24 (0.06)
%D
0.0
-1.9
1.1
-2.1
4.5
41.2
1 Total chlorine, mg/L; temperature, °C; conductivity, pH, pH units; |^S/cm; total alkalinity, mg/L; turbidity, ntu.
A second evaluation of the response to injected contaminants after the extended deployment
used four contaminants. Two were a repeat of the aldicarb injections performed during Stage 2
and two were injections of E. coli, which was not available for injection during the earlier stage
of the test. Table 6-6 shows the directional change of each reference and TitraSip™
measurement in response to the contaminant injections. In general, total chlorine was visibly
affected (through visual observation of both the reference and continuous data) by all four
injections. As shown in Figure 6-12, the reference result in each case was a drop to nearly 0
mg/L of chlorine almost immediately upon injection, but the TitraSip™ measurements did not
drop as low as the reference result during the E. coli injection. Both units only reached
approximately 0.4 or 0.5 mg/L. However, for the first aldicarb injection, both units responded in
the same direction as the reference method. For the last aldicarb injection, Unit 1 responded as it
had for the first injection, but the Unit 2 data were lost because of an operator error during the
downloading process.
As Figure 6-13 shows, turbidity visually appeared to be affected by the first and last injection,
but the results were not as clear for the middle two injections. The reference response to both
E. coli injections and the final aldicarb injection indicated increases in turbidity between the pre-
injection reference sample and the subsequent reference samples, specifically, the E. coli and
31
-------
Table 6-6. Effect of Contaminant Injections After Extended Deployment
Parameter
E. coli
Aldicarb
Reference TitraSip™ Reference TitraSip™
Total chlorine -
Temperature NC NC NC
Conductivity + + NC
pH
Total alkalinity + +
(a)
Turbidity + +
-
NC
NC
-
-
(a)
-------
Figure 6-13. Stage 3 Contaminant Injection Results for Turbidity
aldicarb injections produced changes of 0.82, 0.12, 0.43, and 1.03 ntu, respectively. Because of
the inherent turbidity of an E. coli culture, it was expected that turbidity would be consistently
responsive to that contaminant. Also, because aldicarb was completely dissolved, it was not
expected to increase the turbidity of the water upon injection. However, the conditions
surrounding the injection of both contaminants, such as the potential co-injection of air bubbles,
may have affected the turbidity as much as or more than the contaminant itself. Regardless of
what caused the variations in turbidity, the continuous monitor tracked the relative magnitude of
the change in turbidity rather well for the first E. coli injection and the final aldicarb injection
(data only available for one monitor); but, for the other two injections, the uncertainty of the
background made it difficult to determine if a change occurred.
Figures 6-14 through 6-16 show the effect of the injections on pH, total alkalinity, and
conductivity. The pH was clearly affected by both E. coli injections (as shown by both the
reference and continuous measurements) and, to a lesser extent, by the aldicarb injections. This
was also the case for total alkalinity. Both E. coli injections produced rather sharp downward
spikes in pH and upward spikes in total alkalinity and conductivity. Note that a second E. coli
injection was performed by T&E facility staff (not a part of the ETV test) immediately after the
second E. coli injection. Its effect is observed in all three of these measurements. There was a
downward trend in pH and total alkalinity (for both the reference and TitraSip™ measurement)
during the aldicarb injection. Aldicarb had not altered the pH or total alkalinity during the
Stage 2 injections, so this result was unexpected.
33
-------
8.7
8.6
8.5
8.4
8-3
8.2
8.1
8
7.9
E. coin
E coll 2
Aldicart 3
Aldicart) 4
Figure 6-14. Stage 3 Contaminant Injection Results for pH
Figure 6-15. Stage 3 Contaminant Injection Results for Total
Alkalinity
34
-------
390
E coll1
350
Eco*'2 Aldicarb 3
Aldicarti 4
Each section of this figure represents the time between contaminant injection
and the sensor's return to a baseline measurement (approximately 24 hours)
Figure 6-16. Stage 3 Contaminant Injection Results for Conductivity
6.5 Inter-unit Reproducibility
Two TitraSip™ units were compared throughout the verification test to determine whether they
generated results that were similar to one another. This was done using the TitraSip™ data
collected whenever a reference sample was collected throughout the verification test. Two
evaluations were performed to make this comparison. First, the results from Unit 2 were graphed
on the y-axis, those from Unit 1 were graphed on the x-axis, and a line was fitted to the data.
Second, a t-test assuming equal variances was performed on those same data. For the linear
regression analysis, if both TitraSip™ units reported the identical result, the slope of such a
regression would be unity (1), the intercept zero (0), and the coefficient of determination (r2) 1.0.
The slope can indicate whether the results are biased in one direction or the other, while the
coefficient of determination provides a measure of the variability of the results. The t-test shows
whether the sensors generated statistically similar data. Small p-values (<0.05 at a 5%
confidence level) would suggest that the results from the two units are significantly different
from one another. Table 6-7 gives the slope, intercept, and coefficient of determination for the
inter-unit reproducibility evaluation and the p-value for the t-test performed for each sensor.
As shown in Table 6-7, the pH, temperature, and total chlorine results had coefficients of
determination greater than 0.94 and slopes within 6% of unity, indicating that their results were
very similar and repeatable. Confirming that evaluation, the t-test p-values for the same three
parameters were 0.85, 0.92, and 0.48, respectively, indicating that each unit was generating
statistically similar results. The conductivity sensors had a coefficient of determination greater
than 0.89, indicating that these data were highly correlated with one another; however, the slope
values were approximately 9% and 16% from unity. This reflected the tendency of Unit 1 to
35
-------
Table 6-7. Inter-unit Reproducibility Evaluation
Parameter
Conductivity
pH
Total alkalinity
Turbidity
Temperature
Total chlorine
Slope
1.16
0.94
0.79
0.67
1.06
1.06
Intercept
-38.1
0.545
18.1
0.104
-1.22
0.03
r2
0.896
0.981
0.873
0.683
0.942
0.958
t-test p- value
0.110
0.851
0.149
0.449
0.915
0.481
experience negative spikes throughout the verification test. However, the difference between the
two units was not consistent enough to cause the t-test to indicate a significant difference
between the two units.
The total alkalinity and turbidity results from both units were not statistically different from one
another. Therefore, none of the water quality parameter measurements of the TitraSip™ units
were significantly different. These results were confirmed through visual observation of the
figures throughout Chapter 6 because, when graphed, the data from both units were usually
almost superimposed on each other. The only exception was total alkalinity, for which Unit 2
measurements were consistently higher than Unit 1; but, because of the variability of the Unit 1
measurements, they were not significantly different from each other.
6.6 Ease of Use and Data Acquisition
The TitraSip™ units required daily calibration by the verification staff. Once each day, the
controller was manually rebooted, and an automatic "prime and purge" routine was performed to
prepare the units for the upcoming day's analyses. Analysis routines for the following 24 hours
were programmed at this time. Other daily tasks included checking the levels of total chlorine
and total alkalinity titration reagents and calibration standards for the pH, conductivity, and
turbidity meters. The pH and conductivity meters were calibrated daily by using another
automatic routine, while the turbidity meter was only calibrated once per week. Because the
TitraSip™ units collect a sample from the flowing stream and then perform analyses on that
water sample (conductivity, temperature, pH, turbidity, total alkalinity simultaneously, followed
a few minutes later by total chlorine), they generate a complete set of results approximately
every 30 minutes. Therefore, that is the maximum data collection frequency. These results were
stored in a database that was downloaded into a delimited text file for import into Microsoft®
Excel. The software used to program the calibration and analysis routines was easy to use. Note
that this equipment appeared to be a bench-top instrument (as opposed to a field-deployable
instrument that attaches to a wall).
A month-long period during Stage 3 required in-depth troubleshooting of Unit 1. Initially, the
sample cell on that unit would not drain completely between analyses of separate pH calibration
solutions. The most obvious way in which the problem made itself known was through
decreased pH results (see Figure 6-3) and occasional very high outlying total chlorine results.
Failed conductivity calibrations also made the problem evident. Because the TitraSip™ units
each use a single sample cell for every analysis, any residual sample from a previous calibration
or rinse solution can skew the results of subsequent analyses. The ETV staff worked with the
36
-------
Man-Tech staff to resolve the drain problems. Once resolved, both TitraSip™ units functioned
properly through the end of the verification test. Note that the method for conductivity
calibration was altered near the beginning of Stage 2 of the verification test. This greatly
decreased the percent differences of the conductivity results for the rest of the test.
37
-------
Chapter 7
Performance Summary
Evaluation Parameter
Stage 1 —
Accuracy
Stage 2—
Response to
Injected
Contaminants
Stage 3 —
Accuracy During
Extended
Deployment
Stage 3—
Accuracy After
Extended
Deployment
Stage 3 —
Response to
Injected
Contaminants
Injection
Summary
Inter-unit
Reproducibility
(Unit 2 vs. Unit 1)
Units 1 and 2, range
of %D (median)
Nicotine
Arsenic
trioxide
Aldicarb
Reference
TitraSip™
Reference
TitraSip™
Reference
TitraSip™
Units 1 and 2, range
of %D (median)
Unit 1, %D
Unit 2, %D
E. coli
Aldicarb
Reference
TitraSip™
Reference
TitraSip™
Total
Chlorine
-13.2 to
20.6 (7.5)
-
-
-
-
-
-
-18.0 to
30.0 (2.7)
1.0
0.0
-
-
-
-
Tem-
perature
-9.1 to
52.5 (-0.04)
NC
NC
NC
NC
NC
NC
-15.7 to
3.7 (-3.1)
-2.2
-1.9
NC
NC
NC
NC
Conductivity
37.9 to
94.3 (57.5)(a)
NC
NC
+
+(0
NC
NC
-2.8 to
5.2 (0.7)
0.3
1.1
+
+
NC
NC
pH
-2.2 to
5.4 (0.6)
NC
NC
+
+
NC
NC
-4.4 to
0.7 (-1.1)
-1.0
-2.1
-
-
-
-
Total
Alkalinity
3.2 to
30.4(11.5)
NC
NC
+
+
NC
NC
-16.5 to
14.4 (5.7)
-0.4
4.5
+
+
-
-
Turbidity
-65.2 to
0.6 (-45.2)
(b)
(b)
(b)
(b)
(b)
(b)
-96.7 to 155.3
(-37.3)
35.3
41.2
+
(c)
+
(c)
For a reason that is not clear, aldicarb and total alkalinity altered the pH, as measured by the reference
method, during the Stage 3 injections, but not during the Stage 2 injections.
Slope (intercept)
r2
p-value
1.06 (0.03)
0.958
0.481
1.06 (-1.22)
0.942
0.915
1.16 (-38.1)
0.896
0.110
0.94 (0.545)
0.981
0.851
0.79(18.1)
0.873
0.149
0.67(0.104)
0.683
0.449
All sensors generated results that were similar and repeatable between the units.
Ease of Use and
Data Acquisition
The TitraSip™ units required daily calibration, which involved operator intervention. Initially, the sample
cell on Unit 1 did not drain completely between pH calibration solutions, but once the drain problem was
resolved, both units functioned properly. Monitor results were recorded once every 30 minutes, which is
the maximum data collection frequency.
Calibration procedure for the conductivity meter was changed after Stage 1, resulting in much lower percent
differences throughout the remainder of the verification test.
Relatively large uncertainties in the reference and continuous measurements made it difficult to determine a
significant change.
Duplicate injection results did not agree.
+/- = Parameter measurement increased/decreased upon injection.
NC = No obvious change was noted through a visual inspection of the data.
(b)
(c)
38
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Chapter 8
References
1. U.S. EPA, EPA Method 150.1, pH, in Methods for Chemical Analysis of Water and Wastes,
EPA/600/4-79-020, March 1983.
2. American Public Health Association, et al., SM 2510, Conductivity, in Standard Methods for
the Examination of Water and Wastewater, April 13, 2004.
3. American Public Health Association, et al., SM 2320B, Alkalinity by titration, in Standard
Methods for the Examination of Water and Wastewater, April 13, 2004.
4. American Public Health Association, et al., SM 4500-C1 B, Chloride by silver nitrate
titration, in Standard Methods for the Examination of Water and Wastewater, April 13, 2004.
5. U.S. EPA, EPA Method 170.1, Temperature, in Methods for Chemical Analysis of Water and
Wastes, EPA/600/4-79-020, March 1983.
6. American Public Health Association, et al., SM 2130B, Turbidity, nephelometric, in
Standard Methods for the Examination of Water and Wastewater, April 13, 2004.
7. Test/QA Plan for Verification of Multi-Parameter Water Monitors for Distribution Systems,
Battelle, Columbus, Ohio, August 2004.
8. U.S. EPA, EPA Method 310.1B, Alkalinity—Titrimetric, pH 4.5, in Methods for Chemical
Analysis of Water and Wastes, EPA/600/4-79-020, March 1983.
9. American Public Health Association, et al., SM 4500-G, Residual Chlorine, in Standard
Methods for the Examination of Water and Wastewater, 19th Edition, Washington, D.C.,
1997.
10. Quality Management Plan (QMP)for the ETV Advanced Monitoring Systems Center,
Version 5.0, U.S. EPA Environmental Technology Verification Program, Battelle,
Columbus, Ohio, March 2004.
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