March 2001
NSF 01/26/EPADW395
Environmental Technology
Verification Report
Removal of Arsenic
Watermark Technologies, LLC
eVOX® Model 5
Prepared by
®
NSF International
Under a Cooperative Agreement with
U.S. Environmental Protection Agency
eiVetVeiV
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THE ENVIRONMENTAL TECHNOLOGY VERIFICATION
PROGRAM
&EPA
I'KUliK VM ^
ETV
U.S. Emironmental Protection Agency NSF International
ETV Joint Verification Statement
TECHNOLOGY TYPE:
CHEMICAL COAGULATION/FILTRATION SYSTEM USED
IN PACKAGED DRINKING WATER TREATMENT
SYSTEMS
APPLICATION:
REMOVAL OF ARSENIC
TECHNOLOGY NAME:
eVOX® MODEL 5
COMPANY:
WATERMARK TECHNOLOGIES, LLC
ADDRESS:
12753 SOUTH 125 EAST PHONE: (801)816-1800
DRAPER, UTAH 84020 FAX: (801) 816-0388
EMAIL:
infofajw atermarktechnologies.net
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 substantially 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; stakeholders groups which
consist 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 Treatment Systems
(DWTS) pilot, one of 12 technology areas under ETV. The DWTS pilot recently evaluated the
performance of a Chemical Coagulation/Filtration system used in package drinking water treatment
system applications. This verification statement provides a summary of the test results for the Watermark
Technologies, LLC eVox® Model 5 Coagulation/Filtration System. Cartwright, Olsen & Associates, an
NSF-qualified field testing organization (FTO), performed the verification testing.
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ABSTRACT
Verification testing of the Watermark Technologies, LLC eVox® Model 5 Coagulation/Filtration System
(Watermark eVox® Model 5) was conducted at the Park City, Utah, Spiro Tunnel Water Filtration Plant
from April 11 to April 26, 2000. The source water was groundwater from an abandoned silver mine,
representing one of the sources of drinking water for the City of Park City, Utah. Verification testing was
conducted at the operating conditions specified by the manufacturer. Ferric chloride (FeCt) and sodium
hypochlorite (NaOCl) were metered into the feedwater supply at a rate of 0.094 gallons per hour (gph) of
0.7% FeCl3 and 0.005 gph of 0.42% of NaOCl to effect coagulation. When operated under the designed
conditions at this site, the Watermark eVox® Model 5, removed each arsenic (As) species [total As,
dissolved As and As (V)], from the feedwater supply to an average concentration of less than 4.7 |Jg/L.
TECHNOLOGY DESCRIPTION
The Watermark eVox® Model 5 uses ferric hydroxide [Fe(OH)3] (converted from FeCl3) to react with the
soluble As to produce an insoluble precipitate that can be removed with a backwashing media filter. The
Watermark eVox® Model 5 consists of metering pumps to feed FeCl3and NaOCl into the feedwater
stream, a retention tank to facilitate coagulation, and a repressurization pump to feed coagulated water to
a multi-media filter to continuously remove the precipitated As. The multi-media filter consisted of a 6"
diameter column with a 6" depth of lA" pea gravel, a 6" layer of 8 - 12 mesh course garnet, and a 24"
layer of 60 mesh fine garnet. At four-hour intervals, a timer initiated a five-minute backwashing sequence
utilizing raw water and consisting of a four-minute backwash at 20 gpm per square foot of surface area,
followed by one minute for media settling.
The Watermark eVox® Model 5 is designed for small system applications; this sized unit would serve 15
- 20 people. The test unit is self-contained, skid-mounted and easily transportable by truck. The only
connections required are an inlet line for pressurized feedwater, outlet line for filtrate, drain line for
backwash water, and an electrical connection. The footprint of the unit is approximately 12 ft2 (1.1 m2).
VERIFICATION TESTING DESCRIPTION
Test Site
The verification testing site was the Park City Spiro Tunnel Water Filtration Plant in Park City, Utah. The
source water was the Spiro Tunnel Bulkhead water, which is considered a groundwater source under the
State of Utah source water protection program. Water is developed from water bearing fissures in an
abandoned silver mine tunnel. A five-foot bulkhead built approximately two miles into the tunnel holds
back the water and creates a reservoir. Water is piped from this reservoir to the treatment plant through a
12-inch diameter pipe. The water is considered stable with respect to quality and quantity, and is known
to contain As.
Methods and Procedures
Temperature, pH, turbidity (both on-line and bench-top), and dissolved oxygen analyses were conducted
on both the feedwater and filtrate streams at least once per day at the test site in accordance to Standard
Methods for the Examination of Water and Wastewater, 18th edition (APHA, et. al., 1992). The State of
Utah, Department of Health, Division of Laboratory Services performed analyses daily for alkalinity,
antimony and speciated As [total, dissolved, As (III) and As (V)] on both the feedwater and filtrate
streams. The As speciation procedure (see Appendix C of the Final Report) involved filling containers as
follows: bottle A - as collected; bottle B - filtered through a 0.45|a, filter; and bottle C - portion of the
solution from bottle B run through an ion exchange resin for As (V) removal.
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The Division of Laboratory Services also analyzed hardness, total organic carbon (TOC), UV254
absorbency, aluminum, iron (Fe), manganese, sulfate, and algae (chlorophyll A) on a weekly basis. These
parameters were also measured on a more frequent basis during the verification performance where
eleven sets of samples were collected over a 48-hour period.
VERIFICATION OF PERFORMANCE
System Operation
Verification testing was conducted under manufacturer's specified operating conditions. The flow rate of
the system ranged between 1.0 and 1.1 gpm with a total backwash volume of 16 gallons produced every
four hours during the backwashing operation.
The system initially operated for 24 hours without coagulation chemicals (FeCtand NaOCl). At the end
of this initial operation period, the metering pumps were activated and the coagulant chemicals of
FeCl3and NaOCl were fed into the system. This coagulant addition continued, with only one brief
interruption, for another 328.5 hours.
Evaluation of the required concentration of FeCl3 necessary for optimum As removal was carried out by
means of a simple series of jar tests conducted at the end of March prior to the initiation of the ETV
testing period. Water from the Park City Bulkhead supply source was introduced into the Watermark
eVox® Model 5 treatment equipment with increasing amounts of FeChadded. The samples were then
analyzed during the incremental addition of FeClj. The results were used to determine the FeCl3 injection
concentration for the ETV testing period at approximately 3 mg/L (as Fe).
The Watermark eVox® Model 5 was set to automatically backwash every four hours (based on a timer
setting). The on-line turbidimeter alarm was set to initiate when the filtrate turbidity reached 0.5 NTU.
Based on data gathered during initial operations, it was determined that the backwashing frequency
should be every four hours. Backwash cycles were automatically initiated and controlled with a
timer/controller. This frequency was maintained throughout the duration of the test.
Arsenic Removal
During initial operations, without coagulation chemicals, the media filter removed approximately 49% of
the total As in the feedwater stream and approximately 11.5% of dissolved As was removed. Because Fe
is present in the tunnel water, and this supply is exposed to the air, it is suspected that the resulting
[Fe(OH)3] reacted with a portion of the total As in the feedwater stream forming the insoluble [Fe(OH)3] /
As complex, which was almost 93% removed by the media filter.
During the test period, while coagulant chemicals were being fed to the feedwater stream, approximately
95% of the average total As concentration was removed by this system, with all but two of the filtrate
concentration readings at 2 |jg/L or less. The Watermark eVox® Model 5 removed approximately 89% of
the average dissolved As in the feed water and all of the filtrate samples were at or below 4 |Jg/L, except
for two instances. Almost all of the dissolved As was found as the As (V) species and this species was
removed to an average of 4 |jg/L in the filtrate. The As (III) species was detected near the detection limit
(quantitative at 2 |Jg/L) in the feed water and at the qualitative detection limit (0.5 |Jg/L) in the filtrate. A
summary of the concentrations of As species in both the feedwater and filtrate streams is presented in the
following table.
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Arsenic Data Summary (April 12 - April 26,2000)
based on 22 samples
Feedwater (|Jg/L)
Filtrate (|Jg/L)
Total Arsenic
Average
77.6
4.1
Minimum
60.9
1.2
Maximum
146.0
34.5
Standard Deviation
16.8
8.5
95% Confidence
70.6, 84.6
0.6, 7.6
Dissolved Arsenic
Average
42.0
4.7
Minimum
37.4
1.4
Maximum
45.9
32.6
Standard Deviation
2.5
7.5
95% Confidence
41.0, 43.1
1.5, 7.8
Arsenic (III)
Average
2.5
0.7
Minimum
2.1
<0.5*
Maximum
3.6
1.0
Standard Deviation
0.4
0.2
Confidence Interval
2.4, 2.7
0.6*, 0.8
Arsenic (V)
Average
39.5
4.0
Minimum
35.2
0.9
Maximum
43.8
31.6
Standard Deviation
2.6
7.4
95% Confidence
38.4, 40.6
0.9, 7.1
*A11 readings at the MDL for As (III) (<0.5 |Jg/L) were used as that number in
calculations.
Note: the reliability of the low-level data (MDL of 0.1 |jg/L to approximately 2 |Jg/L)
should be considered only qualitative (not quantitative).
Iron Removal
Fe in the feedwater stream was at an average concentration of 0.268 mg/L and was consistently removed
to below detection limits (<0.02 mg/L) in all samples collected.
Turbidity
Turbidity measurements made both with on-line turbidimeters and the bench-top instrument showed
significant turbidity reduction by the Watermark eVox® Model 5 (in excess of 90%). On-line feedwater
turbidity readings during the testing period averaged 1.51 NTU, compared to the bench-top turbidity
average of 1.66 NTU. The on-line filtrate turbidity readings for the testing period averaged 0.060 NTU,
compared to the bench-top average of 0.13 NTU. Although there was a lack of complete agreement
between the instruments in the measurement of filtrate turbidity, the trend was consistent.
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Operation and Maintenance Results
Testing was initiated at 16:30 hours on April 11, 2000, and except for approximately one hour on April
14 (when a new feed pump was installed), the system ran continuously until 09:00 hours on April 26,
2000. On April 20, 2000, a pinhole leak occurred in the FeCl3 discharge tubing line from the metering
pump, which was quickly repaired. On six occasions, the on-line turbidimeter alarm was initiated,
signaling a filtrate turbidity reading exceeding 0.5 NTU. This always occurred during or immediately
following the automatic backwashing activity, and the alarm shut off automatically within five minutes.
It was concluded that this was due to the generation of turbidity during backwashing with incomplete
settling and no rinse prior to the system returning to operation. By adjusting the backwashing sequence to
allow for complete settling, this problem can be eliminated.
The electrical power used was 110VAC, single phase, 20A service. The power was recorded on an
Amprobe Kilowatt/Hour (kWh) Meter (non-demand). The total power consumed was 359 kWh. The
total quantity of filtrate produced was 23,265 gallons. Total quantity of NaOCl consumed was 0.13
gallons of 5.25% bleach. Total quantity of FeCl3 consumed was 0.67 gallons of a 32.5% FeCl3 solution
All of the sludge from the backwashing operations was collected in a drum, and over the 352.5 hours of
the test, a total of 18.9 liters of a 1% solids concentration was obtained. This is equivalent to 2.1 x 10"6
gallons of sludge produced (100% basis) per gallon of filtrate produced.
Original Signed by
E. Timothy Oppelt 04/18/01
E. Timothy Oppelt Date
Director
National Risk Management Research Laboratory
Office of Research and Development
United States Environmental Protection Agency
Original Signed by
Gordon Bellen 04/27/01
Gordon Bellen Date
Vice President
Federal Programs
NSF International
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 a NSF Certification of the specific product mentioned herein.
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Availability of Supporting Documents
Copies of the ETV Protocol for Equipment Verification Testing for Arsenic Removal
dated March 30, 2000, the Verification Statement, and the Verification Report (NSF
Report #01/26/EPADW395) are available from the following sources:
(NOTE: Appendices are not included in the Verification Report. Appendices are
available from NSF upon request.)
1. Drinking Water Systems ETV Pilot 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
01/26/EPADW395 The accompanying notice is an integral part of this verification statement. March 2001
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March 2001
Environmental Technology Verification Report
Removal of Arsenic
from Drinking Water
Watermark Technologies, LLC
eVox® Model 5
Coagulation/Filtration System
Prepared for
NSF International
Ann Arbor, MI 48105
Prepared by
Cartwright, Olsen and Associates, LLC
Cedar, Minnesota 55011
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. CR 824815. This verification effort was supported by the Drinking Water Treatment Systems Pilot
operating under the Environmental Technology Verification (ETV) Program. This document has been
peer reviewed and reviewed by NSF and EPA and recommended for public release.
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Foreword
The following is the final report on an Environmental Technology Verification (ETV) test performed for
NSF International (NSF) and the United States Environmental Protection Agency (EPA) by Cartwright,
Olsen & Associates, LLC (COA) in cooperation with Watermark Technologies, LLC. The test was
conducted during March and April of 2000 at the Spiro Tunnel Water Filtration Plant, Park City, Utah.
Throughout its history, the EPA has evaluated the effectiveness of innovative technologies to protect
human health and the environment. A new EPA program, the Environmental Technology Verification
Program (ETV) was developed to verify the performance of innovative technical solutions to
environmental pollution or human health threats. ETV was created to substantially accelerate the
entrance of new environmental technologies into the domestic and international marketplace.
Verifiable, high quality data on the performance of new technologies is made available to regulators,
developers, consulting engineers, and those in the public health and environmental protection industries.
This encourages more rapid availability of approaches to better protect the environment.
The EPA has partnered with NSF, an independent, not-for-profit testing and certification organization
dedicated to public health, safety and protection of the environment, to verify performance of small
drinking water systems that serve small communities under the Drinking Water Treatment Systems
(DWTS) ETV Pilot. 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 will meet this goal by working with manufacturers and NSF-qualified Field Testing
Organizations (FTO) to conduct verification testing under the approved protocols. Cartwright, Olsen &
Associates is one such FTO.
The ETV DWTS is being conducted by NSF with participation of manufacturers, under the sponsorship
of the EPA Office of Research and Development, National Risk Management Research Laboratory,
Water Supply and Water Resources Division, Cincinnati, Ohio. It is important to note that verification
of the equipment does not mean that 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.
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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 x
Acknowledgments xi
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 3
1.2.6 Park City Municipal Corporation, Spiro Tunnel Water Filtration Plant 4
1.3 Verification Testing Site 4
1.3.1 Arsenic Chemistry 7
1.3.2 Health Concerns 7
1.3.3 Regulatory 7
1.3.4 Water Source 8
Chapter 2 Equipment Description and Operating Processes 9
2.1 Historical Background 9
2.2 Equipment Description 10
2.3 Operating Process 16
Chapter 3 Methods and Procedures 18
3.1 Experimental Design 18
3.1.1 Objectives 18
3.1.1.1 Evaluation of Stated Equipment Capabilities 18
3.1.1.2 Evaluation of Equipment Performance Relative To Water Quality Regulations 18
3.1.1.3 Evaluation of Operational and Maintenance Requirements 18
3.1.1.4 Evaluation of Equipment Characteristics 19
3.2 Verification Testing Schedule 19
3.3 Initial Operations 19
3.3.1. Water Quality Characteristics 20
3.3.2.1 Feed Water Characteristics 20
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Table of Contents, continued
Section Page
3.3.2.2 Water Quality Data Collection and Analysis 20
3.3.2 Initial Test Runs 21
3.3.2.1 Coagulant Chemistry 21
3.3.2.2 Filter Loading Rate 21
3.4 Verification Task Procedures 21
3.4.1 Task 1 - Verification Testing Runs And Routine Equipment Operation 22
3.4.2 Task 2 - Feed And Finished Water Quality Characterization 22
3.4.3 Task 3 - Documentation of Operating Conditions and Treatment Equipment Performance24
3.4.4 Task 4 - Arsenic Removal 25
3.5 Recording Data 25
3.5.1 Objectives 26
3.5.2 Procedures 26
3.5.2.1 Log Books 26
3.5.2.2 Photographs 27
3.5.2.3 Chain of Custody 27
3.6 Calculation of Data Quality Indicators 27
3.6.1 Representativeness 27
3.6.2 Statistical Uncertainty 27
3.6.3 Accuracy 28
3.6.4 Precision 28
3.7 Equipment 28
3.7.1 Equipment Operations 28
3.7.2 Analytical Equipment 29
3.8 QA/QC Procedures 29
3.8.1 QA/QC Verifications 29
3.8.2 On-Site Analytical Method 30
3.8.2.1 pH 30
3.8.2.2 Temperature 30
3.8.2.3 Turbidity 30
3.8.2.4 True Color 31
3.8.2.5 Total Chlorine 31
3.8.2.6 Particle Free Water (PFW) 31
3.8.2.7 Pressure Gauges 31
3.8.3 Off- Site Analysis for Chemical and Biological Samples 31
3.8.3.1 Organic Parameters, Total Organic Carbon and UV254 Ab sorbance 31
3.8.3.2 Algae (Chlorophyll) Samples 31
3.8.3.3 Inorganic Samples 32
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Table of Contents, continued
Section Page
Chapter 4 Results and Discussion 33
4.1 Introduction 33
4.2 Initial Operations Results 33
4.2.1 Characterization of Influent Water 33
4.2.2 Initial Test Runs 33
4.2.2.1 Coagulant Chemistry 38
4.2.2.2 Coagulant Dosage 38
4.2.3 Filter Run Times 39
4.2.4 Backwashing Frequency 39
4.3 Verification Testing Results 39
4.3.1 Task 1 - Verification Testing Runs And Routine Equipment Operation 39
4.3.2 Task 2 - Feed and Finished Water Quality Characterization 46
4.3.3 Task 3: Documentation of Operating Conditions and Treatment Equipment Performance55
4.3.4 Task 4: Arsenic Removal Results 57
4.4 Results of Equipment Characterization 63
4.4.1 Qualitative Factors 63
4.4.1.1 Susceptibility to Changes in Environmental Conditions 63
4.4.1.2 Operational Reliability 63
4.4.1.3 Equipment Safety 64
4.4.2 Quantitative F actors 64
4.4.2.1 Electrical Power 64
4.4.2.2 Consumables 64
4.4.2.3 Waste Disposal 65
4.4.2.4 Length of Operating Cycle 65
4.5 QA/QC Results 65
4.5.1 Arsenic Speciation and Analysis 65
4.5.2 Data Correctness 66
4.5.2.1 Representativeness 66
4.5.2.2 Statistical Uncertainty 66
4.5.2.3 Accuracy 66
4.5.2.4 Precision 67
4.5.3 Daily QA/QC Results 67
4.5.4 Results Of QA/QC Verifications At The Start Of Each Testing Period 67
4.5.4.1 Tubing 67
4.5.4.2 Thermometer 67
4.5.4.3 Turbidimeters 68
4.5.4.4 True Color 69
4.5.4.5 Total Chlorine 70
4.5.4.6 Pressure Gauges 70
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Table of Contents, continued
Section Page
4.5.4.7 Metering Pump 70
4.5.4.8 Flow Rates 70
4.5.5 OIF- Site Analysis for Chemical and Biological Samples 70
4.5.5.1 Organic Parameters, Total Organic Carbon and UV254 Ab sorbance 70
4.5.5.2 Algae (Chlorophyll) Samples 70
4.5.5.3 Inorganic Samples 71
Chapter 5 References 72
Table Page
Table 1-1. Historical Spiro Tunnel Bulkhead Water Quality Parameters 5
Table 1-2. Selected Inorganic Arsenic Compounds 8
Table 2-1. Maximum and Minimum Operating Conditions 16
Table 2-2. Watermark eVox® Model 5 Coagulation/Filtration System Filtrate Characteristics 16
Table 3-1. Analytical Data Collection Schedule 23
Table 3-2. Operational Data Collection Schedule 24
Table 3-3. Filtration Performance Capability Objectives 25
Table 4-1. Initial Testing without Coagulant Chemicals (April 11, 2000) 34
Table 4-2. Arsenic Data Summaries (no coagulation chemicals) (April 11, 2000) 35
Table 4-3. Total Arsenic Removal Summary (no coagulation chemicals) (April 11, 2000) 35
Table 4-4. Dissolved Arsenic Removal Summary (no coagulation chemicals)
(April 11,2000) 36
Table 4-5. Insoluble Arsenic Removal Summary (no coagulation chemicals)
(April 11,2000) 37
Table 4-6. Chemical Injection Concentrations 38
Table 4-7. Sources, Strengths, Dilution And Flow Rates Of The Coagulant Chemicals 38
Table 4-8. Daily Temperature Data (April 12 - April 26, 2000) 40
Table 4-9. Temperature Data Summary (April 12 - April 26, 2000) 40
Table 4-10. Daily pH Data (April 12 - April 26, 2000) 42
Table 4-11. Daily pH Data Summary (April 11 - April 26, 2000) 42
Table 4-12. Daily Bench-Top Turbidity Data (NTU) (April 12 - April 26, 2000) 43
Table 4-13. Bench-Top Turbidity Data Summary (April 12 - April 26, 2000) 44
Table 4-14. Daily Dissolved Oxygen Data (mg/L) (April 12 - April 26, 2000) 45
Table 4-15. Daily Dissolved Oxygen Data Summary (April 12 - April 26, 2000) 45
Table 4-16. Continuous Turbidity Data Summary (April 12 - April 26, 2000) 46
Table 4-17. Iron Concentrations (April 21 - April 26, 2000) 47
Table 4-18. Iron Data Summary (April 21 - April 26, 2000) 48
Table 4-19. Alkalinity Daily Measurements (April 12 - April 26, 2000) 48
Table 4-20. Alkalinity Data Summary (April 12 - April 26, 2000) 48
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Table of Contents, continued
Table Page
Table 4-21. Antimony Daily Measurements (April 12 - April 26, 2000) 49
Table 4-22. Antimony Data Summary (April 12 - April 26, 2000) 50
Table 4-23. Arsenic Data Measurements (April 12 - April 26, 2000) 51
Table 4-24. Arsenic Data Summary (April 12 - April 26, 2000) 52
Table 4-25. Pressure Drop Data Summary (April 12 - April 26, 2000) 56
Table 4-26. Task 4 Arsenic Data Summary (April 24 - April 26, 2000) 58
Table 4-27. Task 4 Analytical Data for Antimony, Alkalinity, Chlorophyll A and Total Iron (April 24 -
April 26, 2000) 60
Table 4-28. Task 4 Analytical Data for Temperature, pH and Chlorine
(April 24- April 26, 2000) 61
Table 4-29. Task 4 Analytical Data for On-line Turbidity and Bench-Top Turbidity
(April 24 - April 26, 2000) 61
Table 4-30. Task 4 Dissolved Oxygen Data (April 24 - April 26, 2000) 62
Table 4-31. Task 4 Analytical Data - Miscellaneous Parameters (April 24 - April 26, 2000) 62
Table 4-32. Bench-Top Turbidimeter Calibration Verification Data (using 0.4 NTU standard) 69
Table 4-33. Bench-Top Turbidimeter Calibration Verification Data Summary 69
Figure Page
Figure 1-1. Schematic of Spiro Tunnel Water Filtration Plant 6
Figure 2-1. Watermark eVox® Coagulation/Filtration System Schematic 12
Figure 2-2. Illustration of the Watermark eVox® Coagulation/Filtration System 13
Figure 4-1. Total Arsenic Concentrations For Initial Testing Period (no coagulation chemicals) (April
11, 2000) 35
Figure 4-2. Dissolved Arsenic Concentrations For Initial Testing Period (no coagulation chemicals)
(April 11,2000) 36
Figure 4-3. Insoluble Arsenic Concentrations For Initial Testing Period (no coagulation chemicals)
(April 11,2000) 37
Figure 4-4. Antimony Concentration vs. Time (no coagulant chemicals) (April 11, 2000) 37
Figure 4-5. Daily Temperature Data vs. Time (April 12 - April 26, 2000) 41
Figure 4-6. Daily pH Data vs. Time (April 12 - April 26, 2000) 43
Figure 4-7. Daily Bench-Top Turbidity Data vs. Time (April 12 - April 26, 2000) 44
Figure 4-8. Daily Dissolved Oxygen Data vs. Time (April 12 - April 26, 2000) 46
Figure 4-9. Continuous Turbidity vs. Time (April 12 - April 26, 2000) 47
Figure 4-10. Alkalinity vs. Time (April 12 - April 26, 2000) 49
Figure 4-11. Antimony vs. Time (April 12 - April 26, 2000) 50
Figure 4-12. Total Arsenic vs. Time (April 12 - April 26, 2000) 53
Figure 4-13. Dissolved Arsenic vs. Time (April 12 - April 26, 2000) 53
Figure 4-14. Arsenic (HI) vs. Time (April 12 - April 26, 2000) 54
Figure 4-15. Arsenic (V) vs. Time (April 12 - April 26, 2000) 55
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Table of Contents, continued
Figure Page
Figure 4-16. Pressure Drop vs. Run Time (April 12 - April 26, 2000) 57
Figure 4-17. Task 4 Total Arsenic vs. Time (April 24- April 26, 2000) 58
Figure 4-18. Task 4 Dissolved Arsenic vs. Time (April 24- April 26, 2000) 59
Figure 4-19. Task 4 Arsenic (HI) vs. Time (April 24- April 26, 2000) 59
Figure 4-20. Task 4 Arsenic (V) vs. Time (April 24- April 26, 2000) 60
Photographs Page
Photograph 1 - Front view of the Watermark eVox® Coagulation/Filtration System 14
Photograph 2 -View of the Watermark eVox® Coagulation/Filtration System 15
Appendices
A. State of Utah Division Epidemiology and Laboratory Services QA/QC Manual
B. Historical Water Quality Data For Park City, Utah
C. Operations & Maintenance Manual For Watermark eVox® Coagulation/Filtration System
D. Arsenic Speciation Procedure
E. Analytical Reports
F. Certification of Calibration for Pressure Gauge & Bench-Top Turbidimeter
G. On-Site Logbook
H. QA/QC Procedures, Data, and Discussion
IX
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Abbreviations and Acronyms
APHA
AWWA
°C
COA
EPA
ESWTR
ETV
FOD
ft2
FTO
gpm
ICR
L
\i
\igJL
m2
m3/d
MCL
MCLG
MDL
mg/L
mL
NIST
NSF
NTU
PFW
ppb
psi
PVC
QA
QC
SM
SWTR
TDS
TOC
Ten State's Standards
UV254
WEF
WHO
American Public Health Association
American Water Works Association
Degrees Celsius
Cartwright, Olsen and Associates, LLC
U.S. Environmental Protection Agency
Enhanced Surface Water Treatment Rule
Environmental Technology Verification
Field Operations Document
Square foot (feet)
Field Testing Organization
Gallon(s) per minute
Information Collection Rule
Liters
Micron(s)
Microgram(s) per liter (ppb)
Square meter(s)
Cubic meter(s) per day
Maximum Contaminant Level
Maximum Contaminant Level Goal
Mnimum Detection Limit
Milligram(s) per liter
Mlliliter(s)
National Institute of Standards and Technology
NSF International, formerly known as the National Sanitation Foundation
Nephelometric turbidity unit(s)
Particle Free Water
Parts per billion (|_ig/L)
Pound(s) per square inch
Polyvinyl chloride
Quality assurance
Quality control
Standard Methods for the Examination of Water and Wastewater
Surface Water Treatment Rule
Total dissolved solids
Total Organic Carbon
Great Lakes-Upper Mississippi River Board of State Public Health and
Environmental Managers, Recommended Standards for Water Works.
Ultraviolet light absorbance at 254 nanometers
Water Environment Federation
World Health Organization
x
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Acknowledgments
The Field Testing Organization, Cartwright, Olsen & Associates (COA), 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.
Cartwright, Olsen & Associates, LLC
19406 East Bethel Blvd.
Cedar, Minnesota 55011
Phone: (952) 854-4911
Fax(952)854-6964
E-mail: cartwrightconsul@cs.com
Contact: Peter Cartwright, PE.
The laboratory that conducted the analytical work of this study was:
State of Utah
Department of Health
Division of Laboratory Services
46 Medical Drive
Salt Lake City, Utah 84113-1105
Phone: (801) 536-4204
Fax (801) 615-5311
Contact: Larry P. Scanlan, Environmental Scientist m
The Manufacturer of the Equipment was:
Watermark Technologies, LLC
12753 South 125 East
Draper, Utah 84020
Phone: (801)816-1800
Fax (801) 816-0388
E- mail: info@watermarktechnologies.net
Contact: Mark Hashimoto
COA wishes to thank NSF International, especially Mr. Bruce Bartley, Project Manger, and Ms. Carol
Becker and Ms. Kristie Wilhelm, Environmental Engineers, for providing guidance and program
management.
COA is especially indebted to the following individuals at the Spiro Tunnel Water Treatment Plant: John
A. Lind, Assistant Public Works Director, Richard W. Hilbert, Assistant Public Superintendent, Leo
XI
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Williams for his invaluable assistance in monitoring and sample collection speciation, and Jay Glazier and
Scott Clayburn for their assistance to Mr. Williams.
Mr. Larry Scanlan, Environmental Scientist, State of Utah, Department of Environmental Quality,
Division of Drinking Water, deserves special recognition for obtaining and regenerating the anion resin
used for arsenic speciation.
Dr. Zenon Pawlak, Chief of the Radiochem and Metals Lab, Division of Laboratory Services, was
invaluable in his coordination of all laboratory analyses and processing of the resulting data. Wayne
Pierce, Director of the Bureau of Environmental Chemistry and Toxicology, Division of Laboratory
Services, is thanked for his able supervision of all analytical activities.
Xll
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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 substantially 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; stakeholders groups
which consist 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 (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 Treatment Systems
(DWTS) pilot, one of 12 technology areas under ETV. The DWTS pilot evaluated the performance of
the Watermark Technologies, LLC, eVox® Model 5 Coagulation/Filtration System, which is a
backwashable depth filtration system used in package drinking water treatment system applications.
This document provides the verification test results for the Watermark filter system.
1.2 Testing Participants and Responsibilities
The ETV testing of the Watermark Filter System was a cooperative effort between the following
participants:
NSF International
Cartwright, 01 sen & Associates, LLC
Watermark Technologies, LLC
State of Utah Division of Drinking Water Laboratory
U.S. Environmental Protection Agency
Park City Municipal Corporation, Spiro Tunnel Water Filtration Plant
The following is a brief description of each ETV participant and their roles and responsibilities.
1
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1.2.1 NSF International
NSF is a not-for-profit standards and certification organization dedicated to public health safety and 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 that 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 and primary quality oversight of the verification testing. NSF arranged an
inspection of the field analytical and data gathering and recording procedures on April 17 and 18, 2000.
NSF reviewed the Field Operations Document (FOD) to assure its conformance with the pertinent
ETV generic protocol and test plan. NSF also conducted a review or this report and coordinated the
EPA and technical reviews of this report.
Contact Information:
NSF International
789 N. Dixboro Rd.
Ann Arbor, MI 48105
Phone: 734-769-8010
Fax: 734-769-0109
Contact: Bruce Bartley, Project Manager
E-mail: bartley@nsf.org
1.2.2 Field Testing Organization
Cartwright, Olsen & Associates, (COA), a Limited Liability Company, conducted the verification
testing of Watermark eVox® Model 5 Coagulation/Filtration System. COA is a NSF-qualified Field
Testing Organization (FTO) for the Drinking Water Treatment System ETV pilot project.
COA was responsible for conducting the -verification testing. COA provided all needed logistical
support, established a communications network, and scheduled and coordinated activities of all
participants. COA determined that the testing location and feed water conditions were such that the
verification testing could meet its stated objectives. COA prepared the FOD, oversaw the pilot testing,
managed, evaluated, interpreted and reported on the data generated by the testing, as well as evaluated
and reported on the performance of the technology.
COA conducted the onsite analyses and data recording during the testing. Oversight of the daily tests
was provided by Peter Cartwright, of COA.
Contact Information:
Cartwright, Olsen & Associates, LLC
19406 East Bethel Blvd.
2
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Cedar, MN 55011
Contact: Peter Cartwright, P.E., Project Manager
Phone: (952) 854-4911
Fax(952)854-6964
E-mail: cartwrightconsul@cs.com
1.2.3 Manufacturer
The treatment system is manufactured by Watermark Technologies, LLC, a water treatment company.
Watermark Technologies, LLC is a small company based in Salt Lake City, Utah and is dedicated to
the development and marketing of arsenic removal technologies.
Watermark was responsible for supplying a field-ready eVox® Model 5 Coagulation/Filtration System
equipped with all necessary components including treatment equipment, instrumentation and controls
and an operations and maintenance manual. Watermark was responsible for providing logistical and
technical support as needed as well as providing technical assistance to COA during operation and
monitoring of the equipment undergoing field verification testing.
Contact Information:
Watermark Technologies, LLC
12753 South 125 East
Draper, Utah 84020
Phone: (801) 816-1800 Fax (801) 816-0388
Contact: Mark Hashimoto, Chief Executive
E- mail: info@watermarktechnologies.net
1.2.4 Analytical Laboratory
All chemical analyses were performed by the State of Utah Division of Drinking Water Laboratory.
These analyses were made under the direct supervision of Larry P. Scanlan, Environmental Scientist m.
Contact Information:
State of Utah Division of Drinking Water Laboratory
Phone: (801) 536-4204: Fax (801) 615-5311
Contact: Larry P. Scanlan, Environmental Scientist m
E-mail: lscanlan@dep.state.ut.us
The QA/QC manual for this laboratory is located in Appendix A.
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. CR 824815. This verification effort was supported by
3
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the Drinking Water Treatment Systems Pilot operating under the ETV Program. This document was
peer reviewed for technical and quality control content by the EPA.
1.2.6 Park City Municipal Corporation, Spiro Tunnel Water Filtration Plant
Park City Municipal Corporation personnel performed non-supervisory labor associated with the
operation and monitoring of equipment under direct supervision of Peter Cartwright. These activities
included collecting operating data and collection of analytical samples and speciation of arsenic samples.
Contact Information:
Park City Municipal Corporation
445 Marsac Avenue
P.O. Box 1480
Park City, Utah 84060
Contact: Jerry Gibbs, Public Works Director
Phone: (435) 615-5310: Fax (435) 615-4904
The address of the testing site is:
Spiro Tunnel Water Filtration Plant
1884 Three Kings Drive
Park City, Utah 84060
Contact: Rich Hilbert
Phone: (435) 615-5321: Fax (435) 658-9022
1.3 Verification Testing Site
The site selected for challenge testing of the Watermark eVox® Model 5 Coagulation/Filtration System
was the Park City Spiro Tunnel Water Filtration Plant, 1884 Three Kings Drive, Park City, Utah
84060.
The Park City Municipal Corporation has direct access to Spiro Tunnel Bulkhead water. This water
source was used for verification testing. Historical (non-ETV verified water) data at the intake location
are summarized in Table 1-1. A schematic of the Spiro Tunnel Water Filtration Plant is attached as
Figure 1-1.
4
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Table 1-1. Historical Spiro Tunnel Bulkhead Water Quality Parameters
Parameter
Minimum
Maximum
pH
7.3
8.2
Total dissolved solids (TDS) (mg/L)
520
660
Arsenic (Total As) (pg/L)
4
225
Turbidity (NTU)
1
4
Total alkalinity (mg/L asHC03")
17.4
152
Total hardness (mg/L)
420
680
Iron (mg/L)
0.07
2.7
Calcium (mg/L as Ca)
106
160
Chloride (mg/L)
1
10
Sulfate (mg/L)
259
450
Manganese (mg/L)
5
30
Antimony (pg/L)
6
12
Beryllium (pg/L)
<1
5
Cadmium (jag/L)
<1
5
Cyanide (pg/L)
<2
5
Nitrite (N02") (|ug/L)
<0.01
<0.02
Nitrate (N03") (jag/L)
<0.02
8.15
Selenium (pg/L)
<1
<5
Thallium (pg/L)
<2
<500
Mercury (pg/L)
<0.02
<1.1
5
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r
LtCtHO
—RAit «wifn
FIMStt *AICT
BACX WA94 WATER
PU«€ **101
PARK CITY MUNICIPAL CORPORATION
HXHOT 1WTON AM> PfEATOfl EHGKEIMG SP1R0 TUNNEL WATER FILTRATION PLANT
facilities schematic
Figure 1-1. Schematic of Spiro Tunnel Water Filtration Plant
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Influent water quality to the Watermark eVox® Model 5 Coagulation/Filtration System was verified and
documented as a function of the Initial Operations tasks and are detailed in Chapter 4, Results and
Discussions.
Backwash water generated during the verification testing was quantified, sampled and discharged to the
Snyderville Sewer Improvement District. A discharge permit was not required.
1.3.1 Arsenic Chemistry
Arsenic is the 20th most abundant element in the earth's crust and is a component of over 245 minerals.
Because the physical appearance of arsenic resembles that of a metal, it is classified as a metalloid and
is located in group Va of the Periodic Table. It readily forms both oxide and sulfide compounds in the
environment.
Arsenic also enters the environment as the result of both manufacturing and natural processes. Arsenic
trioxide (As203) is formed during smelting operations and has created significant air and land pollution
problems. Arsenic also is released through the burning of certain fossil fuels and volcanic eruptions.
In natural waters, soluble arsenic is virtually always present in the oxidation states of either of +3(m) or
+5(V) valence. An organic species (methylated) has been detected; however, concentrations of this
organic compound rarely exceed 1 part per billion (ppb) and it is considered of little or no significance
as a drinking water contaminant.
In oxygenated waters, the As (V) valence is dominant, existing in the anionic forms of H2As04", HAs04=
and As043. In waters containing little or no oxygen (anoxic), As (III) exists in the nonionic form,
H3As03 below a pH of 9.22, and the anionic form, H2As03~ at a pH above 9.22.
1.3.2 Health Concerns
Arsenic has significant notoriety as a poison, even featured in a stage play, "Arsenic and Old Lace".
Recent studies have indicated that arsenic in drinking water is more dangerous than previously thought,
with risks to exposure comparable to that of radon and second hand tobacco smoke. In humans,
ingested arsenic can cause liver, lung, kidney, bladder and skin cancers. Arsenite [As (m)] is
significantly more toxic than arsenate [As (V)].
1.3.3 Regulatory
The newly established USEPA Maximum Contaminant Level (MCL) for arsenic in drinking water is 10
ug/L, with a Maximum Contaminant Level Goal (MCLG) of 0. The World Health Organization
(WHO) has established a provisional arsenic limit of 10 ppb.
7
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The Table 1-2 lists the properties of selected inorganic arsenic compounds.
Table 1-2. Selected Inorganic Arsenic Compounds
Property Arsenic Arsenic Trioxide Sodium Trioxide Sodium Arsenate
Synonyms
Arsenic black,
colloidal arsenic,
gray arsenic
Arsenic oxide, arsenious
acid, arsenious oxide,
white arsenic
Disodium arsenate,
sodium biarsenate,
arsenic acid disodium
salt
Arsenious acid
sodium salt, sodium
metaarsenite
Chemical formula
As
A.S2O3 (As406)
Na2HAs04
NaAs04
Molecular weight
74.92
197.84
185.91
129.91
Valence state
0
3
5
3
Water Solubility
Insoluble
Soluble
37 g/L at 20°C. 101 g/L at
100°C
Soluble
Very Soluble
1.3.4 Water Source
The Spiro Tunnel Bulkhead source is considered a groundwater source under the State of Utah source
protection program. It is located atN40° 41' 20.8" and Will0 31' 25.0". Water is developed from
water bearing fissures in an abandoned silver mine tunnel at approximately 13,6000 feet into the tunnel,
a five-foot high bulkhead has been constructed to hold back a quantity of water. This water exits the
tunnel through a 12" diameter pipe at a flow rate of 1,150 gpm, and enters the treatment plant, which is
located about 300 yards away. The tunnel is located 1,000 feet or more under remote unoccupied
forest in a mountainous region, and the tunnel entrance is approximately 50 feet below the bulkhead.
There is no use of manmade chemicals on ground above this source.
The water source used for this test is known as the Spiro Tunnel Bulkhead source, is stable with respect
to quality and quantity. Because this water source contains arsenic, for the municipal supply, it is
currently diluted with the treatment plant finished water to form a blend that meets the present arsenic
standard. For this test, only the untreated, unblended Spiro Tunnel Bulkhead supply was used.
The filtration plant was built in February, 1993, has nominal capacity of 1,000 gpm, and is designed to
remove iron, manganese, and arsenic from the raw water. This source is one of five active sources
serving the municipality: 2 tunnels, 2 deep wells, and a spring. The water system serves 6,500 residents,
and as much as 20,000 people per day during the winter season.
Spiro Tunnel Bulkhead water quality before treatment is listed in Table 1-1. These data are historical
and not ETV verified. This table is a summary of water quality data contained in Appendix B.
8
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Chapter 2
Equipment Description and Operating Processes
2.1 Historical Background
The highly respected filtration scientist, Appiah Amirthqarajah, once wrote, "It is ironic that filtration fails
when pretreatment fails, and theory also fails when pretreatment fails." At the same time he commented,
"Chemical pretreatment with particle destabilization is the single most important factor for the production
of the best quality filtered water" (Amirtharajah, 1988).
Particles in colloidal suspensions, where electrostatic forces keep the particles dispersed, have proven
to be a challenge to depth filtration. In many cases, chemical pretreatment, by agglomerating the
particles into larger floe, will allow solids separation of water matrices that otherwise resist filtration.
Large water treatment systems have long employed coagulation, fiocculation, settling and filtration for
the production of quality water. Small systems have been more reluctant to build treatment plants that
use coagulation because of the higher level of operator training required and the need for continuous
monitoring. With the soon to be implemented Interim Enhanced Surface Water Treatment Rules
(IESWTR), and revised arsenic MCL, coagulation may be a suitable technology for smaller systems
allowing them to meet tough new standards with a modest increase in cost.
Only in recent times have we been able to quantify the collection of material within the filter bed,
especially the particulate matter that lies below our visual capabilities. We now know that particles that
we cannot see can also be removed by filtration. Still under investigation, however, are the mechanisms
through which particulate matter is accumulated within the filter media.
It has been assumed that along with simple straining, which is the physical capture of a mass too large to
move through the pores between the media granules, small particles are captured through other
attachment mechanisms. Most of those mechanisms involve a surface charge attraction of the particle to
granulated media and as a result, many experiments have been performed to both better understand the
process and to seek methods to improve it. Some particles are also assumed to be collected by impact
on the surface of the filter media granules; while the actual mechanisms are not clearly understood,
straining is certainly among them.
The most common filtration system used in municipal treatment is the gravity filter, which uses the weight
or head of the water to force it through the filter at very low flow rates. Normal gravity filters, often
called "rapid" sand filters, have a normal flow rate of 3 gpm per square foot of surface, or less. Other
filters, such as slow sand filters, have even slower service flow rates.
Also included among rapid sand filters are pressure filters, where the water is forced through a media
bed by high head pressures and where the media are contained in a pressure vessel. They have long
been used for iron and manganese removal, but have not been as readily accepted for surface water
9
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treatment (Ten State's Standards, 1992). The advantages—especially to small systems—of rapid sand
pressure filters are many. They are relatively passive treatment systems, involve minimal operator
attention, are low in cost and long lived. Of concern, however, is whether pressure filters can capture
and contain particles that are small, and more importantly, contaminants that may pose a threat to public
health, such as arsenic.
Of the several treatment regimens that incorporate coagulation are those that include a settling basin,
where the floe is allowed to settle by gravity and the supernatant decanted and filtered. This is a scheme
common to municipal gravity filter systems. The Watermark Coagulation and Filtration System is a
Direct Filtration System, where the coagulant is added to the raw water in a constant stream, mixed in a
mixing chamber, and then the solids separated through backwashable granulated media filtration.
Because the process stream is slow (approximately 1 gpm), filtration can be accomplished with an off-
the-shelf pressure vessel. The process rate of 1.1 gpm allows for a daily total of 1,584 gallons; thus it is
well suited to small system requirements where waters must be treated to reduce arsenic levels.
Watermark Technologies, LLC has successfully piloted several filtration systems that employ
coagulation as pretreatment.
The primary issue here was whether the Watermark eVox® Model 5 Coagulation/Filtration System
could effectively reduce the total concentration of arsenic to meet the revised arsenic MCL of 10 |LxgfL.
The operation of this equipment is more technically sophisticated than a filter alone, and required more
extensive training in the proper dosing of coagulating chemistry; therefore, the state and municipal health
authorities may have requirements for operation beyond those of a filter. Watermark Technologies,
LLC, requires no special licensing, and will offer operator training upon equipment installation and start-
up.
The wastewater produced by the Park City Municipal Corporation is directed to the raw water wet
well.
2.2 Equipment Description
This environmental technology verification (ETV) test is designed to challenge the Watermark eVox®
Model 5 Coagulation/Filtration System to convert soluble arsenic into an insoluble precipitate and to
remove the precipitate at flow rates of 1 gpm (5 gpm/ft2). Watermark expected that the filter system
would achieve a total arsenic concentration of less than 5|j,g/L, from an influent stream containing up to
90 |j,g/L of arsenic.
The Watermark eVox® Model 5 System included the following components, described in order of
process water flow: Sodium hypochlorite injection into feed water supply via metering pump —> Ferric
chloride injection into feedwater supply via metering pump^ On-line static mixer-^ Flow controls
Retention tank^ Repressurization pump^ Filtration-^ Flow control.
10
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The coagulant chemicals are chlorine plus ferric chloride, injected separately into the feedwater stream
by LMI metering pumps, followed by a reaction module and holding reservoir to facilitate coagulation
The eVox® Model 5 Coagulation/Filtration System utilizes chlorine and ferric chloride (FeCl,) to
convert the arsenate to an insoluble precipitate which is removed by the multimedia filter.
The chemicals are thoroughly mixed in a chemical reaction module of proprietary design, and the
retention tank (holding reservoir) is a 3.7 gallon cylindrical container. In the Park City Spiro Tunnel
Bulkhead Municipal Water Supply, almost all of the arsenic is in the soluble arsenate (V) form (see
ChemTech-Ford letter in Appendix B).
The multimedia filter vessel is six inches in diameter with a six inch deep base of Vi" pea gravel, 6" layer
of 8-12 mesh coarse garnet, and a 24" layer of 60 mesh (0.25 mm) fine garnet.
Figure 2-1 is a schematic of the Watermark System and Figure 2-2 provides additional detail of the
complete Watermark eVox® Model 5 Coagulation/Filtration System. Photograph 1 is a view of the
Watermark eVox® Model 5 Coagulation/Filtration System and Photograph 2 illustrates the coagulant
chemicals and metering pumps.
11
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Raw Water
Retention
Tank
Repressurization
Pump
Pressure Gauge
Pressure Gauge CH
Backwash
Filter Vessel
Flow Meter
Sample Tap
Sanitary Waste
Filtrate
In-Line Turbidimeter —
Figure 2-1. Watermark eVox® Coagulation/Filtration System Schematic
12
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Legend
Pressure Gauge
Solenoid Valve
eVox Chemical Reaction
Module
Inlet Water Source
Chemical Tank
Chemical Pump
Chemical Tank
Chemical Pump
Figure 2-2. Illustration of the Watermark eVox® Coagulation/Filtration System
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Photograph 1 - Front view of the Watermark eVox® Coagulation/Filtration System
-------
Photograph 2 - View of the Watermark eVox® Coagulation/Filtration System
-------
The Watermark eVox® Model 5 Coagulation/Filtration System is designed for small system
applications. The tanks can be made of fiberglass or of steel. The piping is Schedule 80 PVC.
Polyethylene or PVC tanks are used for the reaction tanks and to hold the coagulant chemicals.
Table 2-1 lists the maximum and minimum influent conditions.
Table 2-1. Maximum and Minimum Operating Conditions
Parameter Unit
Inlet flow rate - maximum 1.1 gpm
Inlet flow rate - minimum 0 gpm
Maximum static pressure 100 psi
Minimum inlet dynamic pressure 30 psi
Maximum temperature 90°F (32°C)
Minimum temperature 35°F (1.7°C)
Maximum inlet turbidity 8 NTU
The Watermark eVox® Model 5 Coagulation/Filtration System will produce the following filtrate
characteristics, as listed in Table 2-2.
Table 2-2. Watermark eVox® Model 5 Coagulation/Filtration System Filtrate Characteristics
Parameter Unit
Expected pressure drop
5 psi
Minimum outlet pressure
25 psi
High pH
pH 9
Low pH
pH 6
Maximum temperature
90°F (32°C)
Minimum temperature
35°F (1.7°C)
Normal outlet turbidity
0.10 NTU
Maximum allowable outlet turbidity
0.50 NTU
2.3 Operating Process
The Watermark eVox® Model 5 Coagulation/Filtration System is designed to automatically backwash
(with raw water) under any of the following conditions:
Effluent Turbidity 0.5 or greater (adjustable)
Run Time 4 hours (adjustable)
By Manual Initiation
The usual backwash sequence based on run time is as follows:
Duration Activity
1. 3 hours, 55 minutes filtration
2. 4 minutes backwash at 20 gpm/sq/ft bed area
3. 1 minute system off while media settles
16
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The Watermark eVox® Model 5 Coagulation/Filtration System assumes a finished water storage tank
and intermittent flows, which are common to small system requirements. Several of the control functions
can be initiated by sensors in the storage tank. One such is the return to on-line filtration, initiated when
a storage tank reaches a pre-established low level. The verification study did not employ a storage tank
as the system ran continuously during the verification period.
The Watermark eVox® Model 5 Coagulation/Filtration System claims to achieve an effluent stream
containing less than 5 |j,g/L total arsenic from an influent stream containing up to 225 |j,g/L of total
arsenic at a flow rate of 1.1 gpm (5.5 gpm/ft2 filter bed surface area).
Following are the Watermark eVox® Model 5 Coagulation/Filtration System installation requirements:
• Room temperature range
• Voltage/frequency/amperage
• Ceiling Height
50-120°F
120/220/480 v/60 Hz/ 30 amps
8 feet
17
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Chapter 3
Methods and Procedures
3.1 Experimental Design
This verification study was designed to provide accurate information regarding the performance of the
Watermark eVox® Model 5 drinking water treatment system. Due to the unpredictability of
environmental conditions and mechanical equipment performance, this document should not be viewed
in the same light as scientific research conducted in a controlled laboratory setting.
3.1.1 Objectives
The verification testing was undertaken to evaluate the performance of the Watermark eVox® Model 5
System for arsenic reduction. Specifically evaluated were Watermark's stated equipment capabilities
and equipment performance relative to the removal of arsenic to help communities meet the new MCL.
3.1.1.1 Evaluation of Stated Equipment Capabilities
This ETV study was undertaken to demonstrate the manufacturer's claim that the Watermark eVox®
Model 5 System is capable of producing a filtrate stream containing a maximum of 5 |ig/L total arsenic
at a flow rate of 5-6 gpm/ft2 filter bed surface area from an influent stream containing a maximum of 90
|ig/L total arsenic.
3.1.1.2 Evaluation of Equipment Performance Relative To Water Quality Regulations
With the revised arsenic MCL established at 10 |_ig/L, with an MCLG of 0 |_ig/L, it is expected that the
search for alternative arsenic removal technologies will grow significantly.
3.1.1.3 Evaluation of Operational and Maintenance Requirements
An overall evaluation of the operational requirements for the treatment system was undertaken as part of
this verification. This evaluation was qualitative in nature. The manufacturer's Operations and
Maintenance (O&M) manual, experiences, and events that occurred during the verification period were
used to develop a subjective judgment of the operational requirements of this system. The O&M
manual is attached to this report as Appendix C.
Verification testing also evaluated the maintenance requirements of the treatment system. Not all of the
system's maintenance requirements were necessary due to the short duration of the testing cycle. The
O&M manual details various maintenance activities and their frequencies.
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3.1.1.4 Evaluation of Equipment Characteristics
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 testing cycle creates difficulty
in reliably identifying some of the qualitative, quantitative operational and cost factors. The quantitative
factors examined during the verification were operational aspects of the Watermark eVox® Model 5
System, for example, the measurement of head loss, as well as other factors that might impact
performance. The qualitative factors examined during the verification testing process included the
dosing requirement of the coagulant chemical. Power consumption, waste disposal, and operations and
maintenance issues, and the effect of each on the length of the operating cycle are also addressed. The
operating conditions were recorded to allow reasonable prediction of performance under other, similar
conditions.
3.2 Verification Testing Schedule
After Initial Operations, the Watermark eVox® Model 5 drinking water treatment was operated
continuously for a minimum of 320 hours (the equivalent of 13 full days plus one 8-hour work shift) from
April 12, 2000 until April 26, 2000. During this time, the coagulation and filtration package treatment
equipment operated continuously from start-up until turbidity breakthrough or terminal head loss was
attained. Interruptions in filtration occurred only as needed for backwashing of the filter.
The duration of each filter run and the number of gallons of water produced per square foot of filter area
were recorded in the operational results.
During routine equipment operation, the package water treatment equipment was operated to meet the
system demands and water quality requirements.
3.3 Initial Operations
The objective of the Initial Operations was to establish operational data including coagulant dosage,
filter run times and backwashing schedules, and to qualify the equipment for performance with the
selected source water.
Initial operations allowed Watermark to refine the unit's operating procedures and to make operational
adjustments as needed to successfully treat the source water. Coagulant chemistry and optimum
dosages were determined as well as the relationship between filtrate turbidity and total arsenic
concentration in the filtrate.
The major operating parameters examined during initial operations were coagulant chemistry, filter
loading rate, pressures and flow rates.
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3.3.1. Water Quality Characteristics
3.3.2.1 Feed Water Characteristics
Specifically, the water quality characteristics that were recorded and analyzed were:
Turbidity
Temperature
• pH
• Total Alkalinity
Total Hardness
Total Organic Carbon
Ultraviolet light absorbance at 254 nanometers (UV254)
True Color
Arsenic (concentration by species)
Algae
• Iron
Manganese
• Aluminum
Sulfate
• Antimony
Dissolved Oxygen
3.3.2.2 Water Quality Data Collection and Analysis
Although not required by the Test Plan and not stated in the FOD, analytical samples were collected
daily from the influent (feed) and effluent (filtrate) streams and speciated in order for the State
Laboratory to measure total arsenic, dissolved arsenic, As m and As V, as well as antimony. The
arsenic speciation procedure is detailed in Appendix D; and involved filling containers as follows: bottle
A - as collected; bottle B - filtered through a 0.45 |j, filter; bottle C - portion of the solution from bottle
B run through an ion exchange resin for As (V) removal.
Daily samples were taken beginning on April 11, during Initial Operations and through April 23. On
April 24, Task 4 activities commenced, wherein 11 analytical samples were collected during a 48-hour
period. The entire test was completed on April 26, 2000.
The parameters, which were analyzed as part of this testing and the sampling frequency, are presented
in Table 3-1, Section 3.4. Daily on-site analyses were recorded in the Operations Logbook; semi-
weekly analyses were recorded in the Operations Logbook and also recorded on separate laboratory
report sheets. These data are summarized in Chapter 4, Results and Discussions, and the data
spreadsheets are attached to this report as Appendix E.
Both the feedwater and filtrate streams were sampled for each parameter.
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3.3.2 Initial Test Runs
Before runs were made in which chlorine and coagulant were used, the package plant equipment was
operated with uncoagulated feed water for one 24-hour run. The samples were collected from the feed
water and the filter effluent at 0, 6, 12, 18 and 24 hours of operation to determine if arsenic losses occur
through the system.
3.3.2.1 Coagulant Chemistry
Optimization of coagulant chemistry is dependent on chemical composition and temperature of he
source water. Accordingly, it was of critical importance that coagulant chemistry be studied and tested
prior to performance verification. This was first accomplished with testing to identify suitable coagulant
chemicals, dosage and contact time. Once this testing was complete, initial test runs were performed to
both terminal head loss and turbidity breakthrough. The manufacturer utilized ferric chloride as the
coagulant and used their test unit to optimize the FeCl, dosage. Sodium hypochlorite (NaOCl) was
selected as the oxidant and the dosage of that chemical was optimized at the same time. Information on
these Initial Operations activities is detailed in Appendix B.
3.3.2.2 Filter Loading Rate
Initial filter runs were performed to both terminal headloss and turbidity breakthrough. Total filtered
water volume was measured and the character of finished water was evaluated throughout each filter
run. Terminal head loss was established at 12-psi delta P across the filter. Turbidity breakthrough was
considered reached when the turbidity in the effluent water was 0.50 Nephelometric turbidity unit
(NTU). Backwashing using raw water was initiated manually when turbidity breakthrough occurred.
Filters were backwashed until the waste stream ran clear, as determined by turbidity of 5 NTU or less.
Filters were run in a rinse-to-waste cycle for a minimum of two bed volumes before a filter was returned
to service. Filter service flow rate was established at 5.5 gpm/ft2. Backwash flow rate was established
at 20 gpm/ft2, all within original manufacturer operating specifications for the equipment under test.
Upon return to service, the filter ripening period was monitored and timed. These data were used to
better understand time requirements for backwash, rinse and especially the expected duration of service
run cycles during the testing and verification period.
A four-hour time interval was established for automatic backwashing throughout the duration of the test.
3.4 Verification Task Procedures
The procedures for each task of verification testing were developed in accordance with the
requirements of the EPA/NSF Protocol for Equipment Verification Testing For Arsenic Removal
(EPA/NSF, 2000) and approved in the FOD (dated April, 2000). The Verification Tasks were as
follows:
Task 1 - Verification Testing Runs and Routine Equipment Operation
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Task 2 - Feed and Finished Water Quality Characterization
Task 3 - Documentation of Operating Conditions and Treatment Equipment Performance
Task 4 - Arsenic Contaminant Removal Testing
Detailed descriptions of each task are provided in the following sections.
3.4.1 Task 1 - Verification Testing Runs And Routine Equipment Operation
The objective of this task was to operate the equipment provided by Watermark for the 13.33 day
period and assess its ability to meet water quality goals and other performance characteristics specified
the Manufacturer.
Verification testing consisted of continuous evaluation of the treatment system, using the most successful
treatment parameters defined in Initial Operations. After the Initial Operations period, the total
verification testing was conducted over a period of slightly more than the required 13.33 days (320
hours). During this period, the feed water quality was consistent with the Manufacturer's statement of
performance capability of the equipment. Feed water quality (turbidity and temperature) during this
period ranged from 1.1 to 7.22 NTU (based on on-line turbidimeter readings), and 8.9 to 10.6°C.
Temperature, turbidity, other feed water quality parameters such as algae, natural organic matter, pH,
alkalinity and hardness can influence coagulant chemistry and filtration. In order to offer a "worst case"
challenge to the equipment under test, no attempt was made to lower the turbidity or raise the
temperature of the incoming feed water.
The ETV protocol required the equipment to be run continuously with coagulant chemistry for 13.33
days. This period began on April 12, 2000 at 17:30 and the testing was completed on April 26, 2000
at 0900. During a 24 hour period immediately prior to this run, the system was operated without
coagulant chemistry and analytical samples collected at time 0, 6 hours, 12 hours, 18 hours and 24
hours of operation to determine arsenic and antimony losses (if any) within the system. On-line
coagulation chemistry was monitored by comparing turbidity levels measured at feedwater and filter
effluent. The Watermark eVox® Model 5 System control functions allowed for differing conditions to
indicate the requirement for backwash. These conditions included turbidity breakthrough, filter headloss
and time.
Standard operating parameters for filtration, backwash, and coagulant feed were established through the
use of the manufacturer's O&M Manual and during initial operations of the treatment system. The unit
was then operated under those conditions and operational data were collected according to the
schedule presented in Table 3-1.
3.4.2 Task 2 - Feed And Finished Water Quality Characterization
This task identified the water quality matrices of the influent water and effluent water and the
composition of the removed particulate material, with the relationships to the terminal headloss and/or
22
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turbidity breakthrough point. This information was used to evaluate performance of the water treatment
equipment relative to stated performance goals. Feedwater and finished water parameters were
analyzed and recorded during the verification period according to the schedule in Table 3-1.
Table 3-1. Analytical Data Collection Schedule
Parameter
Facility
Standard Methods' Number or
EPA
Minimum
other method reference
Method2
Frequency
Temperature (°C)
On-site
2550 B
Daily
pH
On-site
4500-Lr B
150.1/150.2
3
Total Alkalinity (mg/L)
Lab
2320 B
Daily
Total Hardness (mg/L)
Lab
200.74
Weekly
Total Organic Carbon (mg/L)
Lab
5310B
Weekly
UV254 Absorbance (cm"1)
Lab
5910 B
Weekly
Turbidity (NTU)
On-site
2130 B/Method 2
180.1
Daily
Aluminum (mg/L)
Lab
200.7
Weekly
Iron (mg/L)
Lab
200.7
Weekly
Manganese (mg/L)
Lab
200.7
Weekly
Suspended Solids in Backwash
Lab
160.2
Task 4
Water (mg/L)
Algae (ng/1)
Lab
10200H
Weekly5
Sulfate (mg/L)
Lab
375.2
Weekly
Dissolved Oxygen (mg/L)
On-site
4500
2120 B (Hach Company
Daily
True Color (TCU)
On-site
modification of SM 2120 measured
in spectrophotometer at 455 nm)
Weekly
Arsenic Concentration and
Lab
200.8
Task 4
Species (|_im)
Antimony (|_im)
Lab
200.8
Task 4
Notes:
'Standard Methods source: 18th Edition of Standard Methods for the Examination of Water and Wastewater, 1992
American Water Works Association.
2 EPA Methods source: EPA Office of Ground Water and Drinking Water. EPA Methods are available from the
National Technical Information Services (NTIS).
3Once per 8 hours during runs with (when test system was staffed) no arsenic sampling. Each time arsenic samples
were taken, coagulant water pH was measured.
Calculated by adding together calcium and magnesium
5Weekly or once during each set of treatment conditions for which arsenic sampling was done.
All data collecting and analytical testing was performed in accordance with the procedures and
protocols established in Standard Methods for the Examination of Water and Wastewater, 18th
Edition (SM) or EPA approved methods. Water sampling ports were located on the feedwater supply
and on the filter effluent.
Turbidity monitors were both continuous and bench. The continuous (on-line) turbidity meter was
checked daily against a bench turbidimeter that was checked against turbidity standards. The bench
turbidimeter was checked against secondary standards with each use. The turbidity instruments for this
study included a HACH Model 17200 (on-line) and a HACH P2100 (bench).
23
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Evaluation of water quality in this task was related to manufacturer's claims of performance for the
Watermark eVox® Model 5 Coagulation/Filtration System, as stated in Section 3.1.1.1, Evaluation of
Stated Equipment Capabilities.
3.4.3 Task 3 - Documentation of Operating Conditions and Treatment Equipment
Performance
During each day of verification testing while the equipment was staffed, operating conditions were
documented. This documentation included description of pretreatment chemistry for coagulation and
such treatment equipment operating data, as flow rate, pressure drop (filter head loss) and backwash
frequency and volume.
Treatment equipment operating parameters for both pretreatment and filtration were monitored and
recorded on a routine basis. Data on filter head loss and backwashing were also collected, as well as
electrical energy consumed by the treatment equipment. Operational data were read and recorded for
each day of the testing cycle. The operational parameters and frequency of the readings are listed in
Table 3-2 below.
Table 3-2. Operational Data Collection Schedule
Operating Data Action
Chemicals Used
Chemical Type, Feed
Volume and Dosage
Feedwater Flow and
Filter Flow
Filter Head Loss
Filtered Water
Production
Filter Backwash
Suspended Solids in
Washwater
Electrical Power
Hours Operated Per
Day
Record on a daily basis.
Type: supplier, commercial and dilution for stock solution to be fed.
Check every two hours. Refill as needed, note volumes and time of refill. Maintain all
calculations on coagulant chemical solution preparation and all data on coagulant
chemicals as purchased from supplier or chemical manufacturer. Calculate the
chemical dosage for each filter run in which arsenic challenge testing was carried out.
Check and record every two hours. Adjust when flow >10% above or below goal.
Record flows before and after adjustment.
Record initial clean bed total head loss at start of filter run. Record total head loss
every two hours. Record terminal head loss at end of filtration.
Record gallons of water produced per square foot of filter bed area for each filter run.
(This figure is the product of filtration rate (gpm/ft2) and length of filter run in minutes
performed at a constant rate).
Record time and durations of each filter backwashing.
Record water volume used to backwash filter.
This requirement is replaced by the process of running all backwash water though a
filter press and measuring total solids in the filter cake at the completion of testing.
Record meter reading once per day.
Record in logbook at end of day or at beginning of first shift on each following
workday.
Note: All Parameters were checked only during times when pilot plant was staffed.
Manufacturer operating performance criteria to which collected data were compared are presented in
Table 3-3.
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Table 3-3 below summarizes the operational objectives of this ETV test.
Table 3-3. Filtration Performance Capability Objectives
Characteristic Definition
Criteria
Initial turbidity Filtrate turbidity at 15 minutes into run
Operating turbidity Turbidity from matured filter
0.1 NTU or less
0.2 NTU or less
0.3 NTU or less in 95% of all samples, or
All turbidity
All data taken at equal intervals
in all data from continuous
turbidimeters
4 hours minimum
Water production Volume of water during a filter run
1,292.5 gallons per sq. ft. (258.5 gallons)
3.4.4 Task 4 - Arsenic Removal
The objective of this task was to evaluate arsenic removal during verification testing by measuring
arsenic concentration naturally present in the feedwater as well as arsenic concentration in the filtrate.
This portion of the study was of central importance, as it measured the effectiveness of the Watermark
eVox® Model 5 Coagulation/Filtration System for arsenic removal.
A task involving a total of 48 hours of operation with collection of 11 arsenic and antimony samples was
conducted to provide statistically verifiable arsenic removal data. This task was initiated immediately at
the conclusion of the 279.5-hour Task 1 activity.
Water quality samples were collected from the plant feed water supply and the filter effluent water
sampling ports. Samples were collected after the treatment plant had been in operation for a total of
three (3) theoretical detention times (the theoretical detention time is the volume of water held in the
treatment equipment divided by the rate of flow) as measured through the pretreatment process up to
the filter. The theoretical detention time ranged from 50 to 70 minutes. Arsenic samples were collected
at time zero and at 1, 3 and 6 hours past time zero. Thereafter arsenic samples were collected once
every 6 hours thereafter until the filter run had lasted 48 hours from time zero. This resulted in collection
of 11 sets of arsenic samples in a 48-hour filter run. During the sampling event, one 250-mL sample
was collected at each sampling location and speciated on-site to allow Laboratory determination of total
arsenic, dissolved arsenic, As (HI) and As (V). Total chlorine concentration of the treated water was
also measured at the same time each sample was collected.
3.5 Recording Data
The water quality parameters and operating data were maintained in the Operations Logbook. All
readings were manually logged.
Also recorded were the following:
Type of chemical added and concentration
Water type (feedwater, filtrate)
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Documentation of study events was facilitated through the use of logbooks, notebooks, photographs,
data sheets and chain of custody forms. Data handling is a critical component of any equipment
evaluation testing. Care in handling data assures that the results are accurate and verifiable. Accurate
sample analysis is meaningless without verifying that the numbers are being entered into spreadsheets
and reports accurately and that the results are statistically valid.
The data management system used in the verification-testing program involved the use of computer
spreadsheet software and manual recording methods for recording operational parameters. The
following describes how data were managed for each parameter.
3.5.1 Objectives
The objective was to tabulate the collected data for completeness and accuracy, and to permit ready
retrieval for analysis and reporting. In addition, the use of computer spreadsheets allowed manipulation
of the data for arrangement into forms, useful for evaluation. A second objective was the statistical
analysis of the data as described in the "NSF/EPA ETV Protocol for Equipment Verification Testing for
Arsenic Removal" (EPA/NSF 2000).
3.5.2 Procedures
The above data handling procedures were used for all aspects of the verification test. Procedures
existed for the use of the log books used for recording the operational data, the documentation of
photographs taken during the study, the use of chain of custody forms, the gathering of on-line
measurements, and the method for performing statistical analyses.
3.5.2.1 Log Books
Data were collected by COA in bound logbooks, a laboratory notebook and on computer generated
charts from the appropriate testing instruments. There was a single field logbook containing all on-site
operating data, which remained cn site and contained instrument readings, on-site analyses and any
comments concerning the test run with respect to either the nature of the feedwater or the operation of
the equipment.
Each page of the notebook was sequentially numbered and identified as Watermark ETV Test. Each
completed page was signed by the on-duty FTO staff. Errors were crossed out with a single line and
initialed. Deviations from the FOD whether by error or by a change in the conditions of either the test
equipment or the water conditions were noted in the notebook. The notebook included a carbon copy
of each page. The original notebook was stored on-site, and the carbon copy sheets retained by the
FTO. This not only eased referencing of the original data, but offered protection of the original record
of results.
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3.5.2.2 Photographs
Photographs were taken with a camera and were utilized by COA to select the most appropriate
photographs for this report.
3.5.2.3 Chain of Custody
Original chain of custody forms traveled with the samples (copies of which are attached as Appendix
E).
3.6 Calculation of Data Quality Indicators
3.6.1 Representativeness
Water quality parameter samples were taken as indicated in Table 3-1. Off-site samples were collected
in accordance with SM 1060B, held and preserved according to SM 5010, and delivered to the
laboratory for analysis. On-site samples were taken utilizing SM 1060B sampling techniques.
3.6.2 Statistical Uncertainty
Statistical 95% confidence calculations were performed for arsenic data, and confidence intervals
determined by taking three discrete samples of arsenic at one operating set during the testing period.
Sampling requirements are noted below in the work plan below. The formula used for confidence
calculations follows:
confidence interval =X + tn-1,1-— (S !-fn)
' 2
S = standard deviation
n = number of measurements in data set
t = distribution value with n-1 degrees of freedom
a = the significance level defined for 95% confidence as: 1- 0.95 = 0.05.
95% confidence interval =X ± tn-\ o 975 (S / -Jfi)
Statistical 95% confidence calculations were also performed for critical water quality data. The above
confidence calculations were used for these water quality data, and results are presented in Chapter 4,
Task 2, Feed and Finished Water Quality Characterization.
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3.6.3 Accuracy
For water quality parameters, the accuracy referred to the difference between the sample result and the
true or reference value. Care in sampling, calibration and standardization of instrumentation and
consistency in analytical technique ensured accuracy.
The pressure gauges used were NIST-traceable standard gauges. Performance evaluation was
established by calibration of instruments used on-site and by conformance to SM and EPA protocols.
3.6.4 Precision
Precision was the measure of the degree of consistency from test to test, and was assured by
replication. In the case of on-site testing for water quality, precision was ensured by multiple tests and
averaging; for single reading parameters, such as pressure and flow rates, precision was ensured by
redundant readings from operator to operator. Travel blanks were not required for this testing.
3.7 Equipment
In order to assure data validity, the EPA/NSF Verification Testing Plan procedures were followed.
This ensured the accurate documentation of both water quality and equipment performance. Strict
adherence to these procedures resulted in verifiable performance of equipment. A summary of how the
Watermark system testing and analytical equipment was operated during the verification testing is
presented in this section.
3.7.1 Equipment Operations
The operating process for the Watermark eVox® Model 5 System is described in the Operations
Manual (Appendix B), which was maintained on site.
In summary, the system works by the injection of sodium hypochlorite into the water stream followed by
the injection of ferric chloride. The ferric chloride is oxidized by the sodium hypochlorite to ferric
hydroxide. Based on studies by Clifford, et al, the arsenic removal mechanism can be modeled as an
adsorption phenomenon. A ligand exchange process dominates, and in the presence of ionic arsenic, an
arsenate ion replaces an hydroxide ion in the structure of the ferric hydroxide and this arsenic compound
precipitates with the insoluble ferric hydroxide.
The insoluble ferric hydroxide is filtered out of the water stream by the multimedia filter, which is
automatically backwashed, based on a timer interval or initiated by either turbidity breakthrough or
terminal headloss.
Residence time to ensure a complete chemical reaction between the ferric chloride, sodium hypochlorite
and arsenic ion was accomplished by a retention tank located between the chemical injection pumps
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and the filter unit. At the operating rate of 1.1 gpm, the residence time in the retention tank (holding
reservoir) was 3.3 minutes.
3.7.2 Analytical Equipment
The following analytical equipment was used on-site during the verification testing:
• A Hach 2100P portable turbidimeter (serial number 000100024023) was used for benchtop
turbidity analyses. A Certificate of Conformance for this meter is located in Appendix F.
Pressure gauge was a National Institute of Standards and Technology (NIST) traceable pressure
gauge (Ametek Model number 1980L, Certification number 0084-6). There were two pressure
gauge quick-connect fittings on the system, located on the inlet and outlet of the filter vessel. The
Certificate of Calibration for this gauge is located in Appendix F.
RadioShack Model No: 63-1009A indoor-outdoor thermometer was used for the measurement
of temperature. This RadioShack thermometer was calibrated against a NIST-traceable
Thermometer (Tel-Tru model 0054-5).
A rotometer [(Blue and White model F40750-LN16 (0 to 10 gpm)] was used to measure flow
rates.
On-line turbidity measurements were taken with a HACH 17200 turbidimeter.
Chlorine measurements were taken with a HACH 2010 spectrophotometer.
Dissolved oxygen measurements were taken with a Hach "sension 8" dissolved oxygen meter,
serial no. 990900000112.
pH measurements were taken with an Oakton pH/mV/°C meter, part no. 35615-00.
3.8 QA/QC Procedures
The objective of the Quality Assurance/Quality Control (QA/QC) was to control the methods and
instrumentation procedures such that the data were not subject to corruption. Adherence to analytical
methods as published in SM and EPA Methods was assured. Moreover, instrumentation and standard
reagents were referenced to NIST. Instruments used to gather data were standardized and calibrated in
accordance with the schedules noted below.
3.8.1 QA/QC Verifications
Daily QA/QC Verifications included:
On-line turbidimeter readings standardized against a calibrated bench turbidimeter, which was
calibrated against secondary standards with each use.
pH meter calibration was verified at pH 4, 7 and 10 with NIST-traceable pH buffers
QA/QC Verifications at the beginning of each testing period included:
Cleaning and re-calibration of on-line turbidimeters;
Pressure gauges with NIST-traceable gauge;
Inspection of turbidimeter tubing for unimpeded flow and integrity.
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Calibration of test unit flow meter using "bucket and stopwatch" method. Although this activity
was performed on April 26, 2000, in error, it was not recorded in the Laboratory Notebook.
Further descriptions of these verification procedures are provided below.
3.8.2 On-Site Analytical Method
Specific Instrumentation methods for on-site QA/QC accuracy were as follows:
3.8.2.1 pH
Analyses were made by SM 4500-H+, A three-point calibration with NIST-traceable pH buffers was
performed daily. Between tests, the pH probe was kept wet in KC1 solution. For on-site determination
of pH, field procedures were used to limit absorbance of carbon dioxide to avoid skewing results by
poorly buffered water.
pH measurements do not lend themselves to "blank" analyses. Duplicates were run once a day.
Performance evaluation samples were analyzed during the testing period. Results of the duplicates and
performance evaluation were recorded. The unit was also calibrated against a standardized pH
instrument in the State of Utah Laboratory and found to be within 5% accuracy.
3.8.2.2 Temperature
Temperatures were measured in accordance with SM 2550, at least once per day. The thermometer
read in 0.1° C increments and calibrated by the State of Utah Laboratory as well as against a NIST-
traceable thermometer.
3.8.2.3 Turbidity
The turbidimeters remained on during the duration of the testing period. On-line and bench top
turbidimeters were used, and the bench top turbidimeter was the calibration standard for tie test.
Manufacturer's procedures for maintenance were followed and the schedules for maintenance and
cleaning noted in the logbook. All glassware was dedicated and cleaned with lint free tissues to prevent
scouring or deposits on the cells. The calibration of the bench-top turbidimeter (Hach 21 OOP) was
verified on March 15, 2000, using Hach StablCal® Standards (Stabilized Formizin Turbidity
Standards) of 800, 100, 20 and <0.1 NTU. On a weekly basis, the instrument calibration was verified
using secondary standards of Hach Gelex measuring 526, 52.2 and 4.87 NTU. Another secondary
standard, measuring 0.4 NTU was used to verily calibration before every use. SM2130 was employed
for measurement of turbidity.
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3.8.2.4 True Color
True color was measured in accordance with SM 2120 at 455nm wavelength with a Hach DR2010
spectrophotometer.
3.8.2.5 Total Chlorine
Total chlorine measurements were made in accordance with SM 4500 on a Hach DR2000
spectrophotometer which was standardized with each set of measurements in accordance with the
method.
3.8.2.6 Particle Free Water (PFW)
The State of Utah, Department of Health, Division of Laboratory Services, provided water for our use
at the site. The ultra-pure water was brought from the Laboratory in new, transparent, polyethylene
one-gallon bottles marked and dedicated for this purpose.
This water was prepared by treating with reverse osmosis, followed by exchange deionization resins.
3.8.2.7 Pressure Gauges
The pressure gauge for this study was a glycerin-filled, NIST-traceable and calibrated against an
Ametek Model 1980L Gauge (0- 60 psig).
3.8.3 Off-Site Analysis for Chemical and Biological Samples
3.8.3.1 Organic Parameters, Total Organic Carbon and UV254 Absorbance
Samples for these analyses were collected in glass bottles supplied by the State of Utah Laboratory and
delivered to the Laboratory by COA at least twice a week. Metals samples were collected in acidified
bottles and all samples held for no more than three days at 4°C prior to delivery to the Laboratory in
accordance with SM 5010B and SM 1060. This processing procedure is reflected in the chain of
custody forms located in Appendix E. Table 3-1 lists the SM number used for these tests.
3.8.3.2 Algae (Chlorophyll) Samples
Samples were collected in opaque containers supplied by the State Laboratory and kept at 0°C in the
on-site refrigerator prior to delivery to the laboratory. Table 3-1 lists the sampling frequency and SM
number used.
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3.8.3.3 Inorganic Samples
Inorganic samples were collected, held in the refrigerator at 4°C, and shipped in accordance with SM
3010B and C and 1060 and EPA §136.3, 40 CFR Ch.l. Proper bottles and preservatives, where
required (iron and manganese for example) were used. Although the travel time was brief, samples
were shipped in coolers at 4° C. The appropriate SM and EPA test methods and minimum testing
frequencies are listed in Table 3-1.
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Chapter 4
Results and Discussion
4.1 Introduction
Complete verification testing of the Watermark eVox® Model 5 Coagulation/Filtration System, which
occurred at the Park City Spiro Tunnel Water Filtration Plant, commenced on April 11, 2000, and
concluded on April 26, 2000.
This section of the verification report presents the results of the Initial Operations period as well as the
Verification Testing period and a discussion of the results. Results and discussions of the following are
included: initial operations, verification tasks, and QA/QC.
4.2 Initial Operations Results
An Initial Operations period allowed COA and Watermark to refine the unit's operating procedures
and to make operational adjustments as needed to successfully treat the source water. The primary
goals of the Initial Operations period were to establish an optimum process of coagulant chemistry,
coagulant dosage, filter run times and backwashing frequency.
4.2.1 Characterization of Influent Water
Historical untreated surface water quality data that were obtained from Park City Municipal
Corporation showed that the Spiro Tunnel Bulkhead water exhibited the following characteristics as
shown in Table 1-1. Review of these historical data indicated that the technology should be suitable for
this site.
4.2.2 Initial Test Runs
The Test Plan required that an initial test run be performed with uncoagulated feed water, and that
samples be collected after 6, 12, 18 and 24 hours of operation. This activity was intended to determine
if arsenic is removed from the system in the absence of coagulant chemicals. Tables 4-1 through 4-5
and Figures 4-1 through 4-3 provide the analytical results of this Initial Operations activity for a number
of parameters.
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Table 4-1. Initial Testing without Coagulant
Parameter
Chemicals (April 11,2000)
Hour 0 Hour 6
Hour 12
Hour 18
Hour 24
As (total) (ug/L)
Feedwater 78.1
Filtrate 37.3
As (dissolved) (ug/L)
Feedwater 38.8
Filtrate 30.2
As (insoluble) (ng/L)
1 Feedwater 39.3
2 Filtrate 7.1
As (III) (ng/L)
Feedwater 2.5
Filtrate <0.5*
As (V) (ug/L)
Feedwater 36.3
Filtrate 29.7
Antimony (|Jg/L)
Feedwater 9.2
Filtrate 10.4
In-Line Continuous Turbidity (NTU)
Feedwater 1.64
Filtrate 0.107
Bench Turbidity (NTU)
Feedwater 2.43
Filtrate 0.23
Alkalinity (mg/L)
Feedwater 144
Filtrate 145
Temperature (°C)
Feedwater 8.9
Filtrate 9.9
pH
Feedwater 7.39
Filtrate 7.42
Dissolved Oxygen (mg/L)
Feedwater 6.09
Filtrate 6.16
70.6
36.2
38.3
35.5
32.3
0.7
2.7
2.5
35.6
33
9.0
8.9
1.67
0.10
142
145
9.7
9.9
7.36
7.43
6.26
6.47
71.3
35.3
39.5
34.2
31.8
1.1
2.7
2
36.8
32.2
9.1
8.9
1.82
0.07
1.68
0.13
146
146
10.9
9.9
7.30
7.37
5.59
5.83
68.9
37.7
38.5
35.9
30.4
1.8
2.7
2.6
35.8
33.3
8.7
9.0
1.73
0.059
1.63
0.13
144
145
8.9
10.0
7.30
7.39
5.91
5.75
75.2
38.7
40.4
37.3
34.8
1.4
2.4
1.9
38
35.4
9.1
9.0
1.77
0.057
1.69
0.15
146
146
8.9
10.0
7.30
7.40
6.28
5.78
*A11 readings at the MDL were used as that number in calculations.
1 Feedwater Insoluble As = Total Feedwater As - Dissolved Feedwater As
2 Filtrate Insoluble As = Total Filtrate As - Dissolved Filtrate As
34
-------
Table 4-2 summarizes the arsenic species from Table 4-1.
Table 4-2. Arsenic Data Summaries (no coagulation chemicals) (April 11,2000)
As (total) (ng/L) As (dissolved) As (insoluble) (ng/L) As III (ng/L) As V (jxg/L)
(Hg/L)
Feedwater Filtrate Feedwater Filtrate Feedwater Filtrate Feedwater Filtrate Feedwater Filtrate
Average
72.8
37.0
39.1
34.6
33.7
2.4
2.6
1.9
36.5
32.7
Min.
68.9
35.3
38.3
30.2
30.4
0.7
2.4
<0.5*
35.6
29.7
Max.
78.1
38.7
40.4
37.3
39.3
7.1
2.7
2.6
38
35.4
Std. Dev
3.7
1.3
0.9
2.7
3.5
2.6
0.1
0.8
1.0
2.1
95% CI
69.5,76.1 35.9, 38.2
38.3, 39.9
32.2, 37.0
30.7, 36.8
0.1,4.7
2.5,2.7
1.2, 2.6
35.7, 37.3
30.9,
34.5
* All readings at the Minimum Detection Limit (MDL) for Arsenic III of (<0.5 (ig/L) were used as that number in
calculations.
Note: The reliability of the low level (MDL of 0.1 ng/L to approximately 2 (xg/L) should be considered as only
qualitative (not quantitative).
Figure 4-1 demonstrates reduction in total arsenic concentrations during the 24-hour Initial Operations
period.
o>
o
80
70
60
50
40
30
20
10
0
-1 1 1—
6 12 18
Hour of Initial Test Run
24
¦As Total Feedwater*
¦As Total Filtrate
Figure 4-1. Total Arsenic Concentrations For Initial Testing Period (no coagulation chemicals) (April 11,2000)
Average removal for Total As for the 24-hour Initial Operations period are provided in Table 4-3:
Table 4-3. Total Arsenic Removal Summary (no coagulation chemicals) (April 11,2000)
Average
72.8
37.0
Minimum
68.9
35.3
Maximum
78.1
38.7
Standard Deviation
3.7
1.3
95% Confidence Interval
69.5, 76.1
35.9, 38.2
35
-------
Figure 4-2 illustrates the dissolved arsenic concentrations during the Initial Operations period. As
shown in this figure, the data suggest that there is very little removal of dissolved arsenic by the filter
alone without the addition of coagulation chemicals.
40
nr
o>
30
3-
o
£
20
0)
j"
<
10
0
—t-
-o-
-1 1 1—
6 12 18
Hour of Initial Test Run
24
H—As (dissolved) Feedwater —~—As (dissolved) Filtrate
Figure 4-2. Dissolved Arsenic Concentrations For Initial Testing Period (no coagulation chemicals) (April 11,
2000)
Average removal for dissolved arsenic for the 24-hour Initial Operations period are provided in table 4-
4:
Table 4-4. Dissolved Arsenic Removal Summary (no coagulation chemicals) (April 11,2000)
Dissolved As in Feedwater (|ig/L) Dissolved As in Filtrate (|ig/L)
Average
Minimum
Maximum
Standard Deviation
95 % Confidence Interval
39.1
38.3
40.4
0.9
38.3, 39.9
34.6
30.2
37.3
2.7
32.2, 37.0
The average dissolved As concentration in the filtrate stream is somewhat lower than that in the
feedwater stream. While this reduction is minimal, it is greater than expected.
Figure 4-3 illustrates the insoluble arsenic concentrations during the Initial Operations period. As shown
in this figure, the data suggest significant removal of insoluble arsenic by the filter alone without the
addition of coagulation chemicals.
It is postulated that the iron present in the feedwater supply oxidizes in the presence of air and forms an
insoluble complex with a portion of the arsenic in the feedwater supply. This accounts for the average
reduction in insoluble arsenic from an average of 33.7 |jg/L in the feedwater to an average of 2.4 |_tg/L
in the filtrate (Table 4-5).
36
-------
IT 30
O)
3r
.2 20
£
0)
£
< 10
=X:
6
zX:
-X-
12
Hour of Initial Test Run
18
24
¦As (insoluble) Feedwater —X —As (insoluble) Filtrate
Figure 4-3. Insoluble Arsenic Concentrations For Initial Testing Period (no coagulation chemicals) (April 11,
2000)
Table 4-5. Insoluble Arsenic Removal Summary (no coagulation chemicals) (April 11,2000)
Average
33.7
2.4
Minimum
30.4
0.7
Maximum
39.3
7.1
Standard Deviation
3.5
2.6
95 % Confidence Interval
30.7, 36.8
0.1,4.7
Figure 4-4 illustrates the antimony concentrations in both feedwater and filtrate streams during the initial
run when no coagulant chemicals were added. Review of this figure suggests very little removal of
antimony by the Watermark unit.
Figure 4-1. Antimony Concentration vs. Time (no coagulant chemicals) (April 11, 2000)
37
-------
4.2.2.1 Coagulant Chemistry
Evaluation of the required concentration of FeCl, necessary for optimum arsenic removal was carried
out by means of a simple series of jar tests conducted on February 22, 2000, prior to the initiation of
the ETV testing period. Water from the Park City Bulkhead supply source containing an average of 80
Hg/L total As was introduced into the eVox® treatment equipment with increasing amounts of ferric
chloride added. This average total As was verified by Mr. Ron Fuller (Consultant to Watermark
Technologies LLC). The samples were then analyzed and the results were used to fix the ferric chloride
injection concentration for the ETV testing period at approximately 3 mg/L (as Fe).
Table 4-6. Chemical Injection Concentrations
Concentration of Iron Added (mg/L as Fe) Residual Chlorine (mg/L as Cl2) Filtrate Total Arsenic (|ig/L)
1
1
6.6
1.5
1
4.5
2
1
2
2.3
1.25
2
3
0.37
1.3
3.6
1.18
0.5
4
1.37
1.1
It had already been determined that the major component necessary for arsenic reduction in the
Bulkhead water supply was iron, and that little additional oxidation enhancement was required.
However, the Park City water sources had experienced historical fluctuations in the concentration of
arsenic as well as other elements; it was therefore decided by the manufacturer to maintain a residual
chlorine concentration of 1 mg/L as an insurance measure against the need for unforeseen oxidation
requirements.
To achieve the desired outlet pressure from the feedwater pump, the flow rate was 2 gpm. This is the
flow into which the coagulant chemicals were metered. The feedwater flow rate that was directed into
the Watermark eVox® Model 5 Coagulation/Filtration System was 1.1 gpm, with the reminder of the
feedwater flow, containing ferric chloride and sodium hypochlorite, directed to the Snyderville Sewer
Improvement District.
4.2.2.2 Coagulant Dosage
The sources, strengths, dilution and flow rates of the coagulant chemicals were established as follows:
Table 4-7. Sources, Strengths, Dilution And Flow Rates Of The Coagulant Chemicals
Parameter Sodium Hypochlorite
Ferric Chloride
Source
Whirl Brand (Grocery Store)
Thatcher Chemical
Strength (as supplied)
5.25%
32.5%
Dilution* (as fed)
0.42%
0.7%
Metering Rate
0.005 gph
0.094 gph
Feedwater Concentration (at 1.1 gpm)
0.175 mg/L (as NaOCl)
5.48 mg/L (as FeCl3)
*Plant Tap Water
38
-------
The above parameters were maintained throughout the duration of the test.
4.2.3 Filter Run Times
The Watermark eVox® Model 5 Coagulation/Filtration System was set to automatically backwash
every four hours (based on a timer setting). The on-line turbidimeter alarm was set to initiate when the
filtrate turbidity reached 0.5 NTU. On six occasions, the alarm was activated, but it automatically shut
off in less than five minutes on each occasion. Based on observations made by the equipment operator,
and recorded in the laboratory notebook, filtrate turbidity exceeded 0.5 NTU on April 16, 18, 21 and
22 for a short period. In each case this occurred immediately after timer activated backwashing, and
recovered in less than five minutes. No adjustments were made to the filter run schedule; however, the
control system can be adjusted to allow for a longer settling time, thereby eliminating this problem.
4.2.4 Backwashing Frequency
Based on data gathered during Initial Operations, it was determined that the backwashing frequency
should be every four hours. Backwash cycles were automatically initiated and controlled with a
timer/controller. This frequency was maintained throughout the duration of the test. Raw feedwater
was used as the source of the backwash water.
4.3 Verification Testing Results
4.3.1 Task 1 - Verification Testing Runs And Routine Equipment Operation
Automatic coagulant feeding was initiated at 1730 on April 12, 2000, immediately at the conclusion of
the 24-hour Initial Testing period.
On April 14, it was noticed that the feedwater pump was emitting extraneous sounds that suggested the
potential of eventual pump failure. It was suspected that the bearings on this pump were beginning to
fail, therefore from 0750 to 0840, the unit was shut down and a replacement pump (a Teel multistage
centrifugal pump) was installed.
At 0130 on April 20, 2000, a leak in the tubing from the FeCl, metering pump into the static mixer was
observed. It was repaired with tape, but at approximately 0940, a leak around the tape was observed.
The tubing was cut off at that point and reinserted into the pump discharge.
At least once per day, the following parameters were measured on-site on both the feedwater and
filtrate streams:
• Temperature
• pH
• Bench-Top Turbidity
• Dissolved Oxygen
• Total Chlorine
39
-------
Daily temperature readings for the verification testing period are listed in Table 4-8.
Table 4-8. Daily Temperature Data (April 12- April 26,2000)
Date Time , Temperature (°C)
Feedwater Filtrate
4/12/00
1900
9.0
10.0
4/13/00
1135
9.3
10.1
4/14/00
0900
8.9
10.0
4/14/00
1445
8.9
8.5
4/15/00
1345
8.9
10.0
4/15/00
1630
8.9
10.0
4/16/00
0830
8.9
10.0
4/17/00
0800
8.9
10.0
4/17/00
0845
8.9
10.0
4/18/00
1345
9.4
10.8
4/19/00
1245
9.3
10.4
4/20/00
0830
9.2
10.2
4/21/00
1030
9.2
10.2
4/22/00
0930
9.3
10.3
4/23/00
1000
10.6
9.7
4/24/00
900
9.7
10.7
4/24/00
1000
9.6
10.7
4/24/00
1200
9.3
9.8
4/24/00
1500
9.6
10.6
4/24/00
2100
9.9
10.1
4/25/00
300
9.6
10.5
4/25/00
900
9.7
10.5
4/25/00
1500
9.7
10.7
4/25/00
2100
9.7
10.7
4/26/00
300
9.7
10.6
4/26/00
900
9.6
10.5
These data are summarized and plotted in the following tables and figures. Note that the multiple
readings for temperature as required for Task 4 for the period of April 24 through 26 are included in the
graphs as additional data points.
Table 4-9. Temperature Data Summary (April 12- April 26,2000)
Feed (°C) Filtrate (°C)
Average 9.4 10.2
Minimum 8.9 8.5
Maximum 10.6 10.8
Standard Deviation 0.4 0.5
95% Confidence Interval 9.2, 9.5 10.0,10.4
Note that there is approximately a 1°C increase in temperature from the feed to the filtrate stream as
shown in Figure 4-5. This increase is likely due to the residence time in the equipment, which was
installed in an area where the ambient temperature was maintained by the facility at approximately 70°F
(21° C).
40
-------
12.0
10.0 0—a
o
o
d>
1.
3
re
i.
a>
Q.
E
a>
6.0
4.0
2.0
e
0.0 H 1 1 1 1 1 1 1 1 1 1 1 1 1
///////////////
Date
•Feedwater —0—Filtrate
Figure 4-5. Daily Temperature Data vs. Time (April 12- April 26,2000)
Daily pH measurements taken during the verification testing period are shown in Table 4-10.
41
-------
Table 4-10. Daily pH Data (April 12- April 26,2000)
Date Time Feedwater
Filtrate
Coagulated
Feedwater
4/12/00
1900
7.31
7.19
-
4/13/00
1135
7.32
7.23
-
4/14/00
0900
7.33
7.22
7.14
4/14/00
1445
7.38
7.22
7.10
4/15/00
1345
7.27
7.07
-
4/15/00
1630
7.26
7.15
7.09
4/15/00
1900
7.21
7.12
7.08
4/16/00
0800
7.23
7.15
7.10
4/16/00
1600
7.27
7.17
7.14
4/17/00
0845
7.24
7.16
7.18
4/18/00
0920
7.21
7.09
7.14
4/18/00
2000
7.22
7.10
7.06
4/19/00
1700
7.27
7.17
-
4/20/00
0830
7.33
7.43
-
4/21/00
1030
7.31
7.22
-
4/21/00
1845
7.25
7.15
-
4/22/00
0930
7.32
7.27
-
4/22/00
2200
7.24
7.19
-
4/23/00
1000
7.31
7.18
-
4/23/00
1920
7.29
7.18
-
4/24/00
900
7.33
7.23
-
4/24/00
1000
7.33
7.37
-
4/24/00
1200
7.29
7.17
-
4/24/00
1500
7.38
7.26
-
4/24/00
2100
7.34
7.22
-
4/25/00
300
7.33
7.17
-
4/25/00
900
7.33
7.25
-
4/25/00
1500
7.35
7.22
-
4/25/00
2100
7.34
7.20
-
4/26/00
300
7.31
7.18
-
4/26/00
900
7.29
7.19
-
- No measurement taken
The filtrate pH is virtually always lower than the feedwater pH. This is likely due to the addition of
acidic ferric chloride to effect coagulation. This is underscored by the pH data in Table 4-1 that show
that without ferric chloride, the average filtrate pH was higher than that of the feedwater.
Table 4-11. Daily pH Data Summary (April 11 - April 26,2000)
Feed
Filtrate
Coagulated Feedwater
Average
7.30
7.20
7.11
Minimum
7.21
7.07
7.06
Maximum
7.38
7.43
7.18
Standard Deviation
0.05
0.07
0.04
95% Confidence Interval
7.28,7.31
7.17,7.22
7.09,7.14
The multiple readings for pH as required for Task 4 for the period of April 24 through 26 are included
in Figure 4-6 as additional data points.
42
-------
Date
—•— Feedwater —o— Filtrate —ii— Coagulated Feedwater
Figure 4-6. Daily pH Data vs. Time (April 12- April 26,2000)
Table 4-12 lists the Bench-Top turbidity readings for the testing period.
Table 4-12. Daily Bench-Top Turbidity Data (NTU) (April 12- April 26,2000)
Date Time Feedwater (NTU) Filtrate (NTU)
4/12/00
1900
1.69
0.12
4/13/00
1135
1.73
0.29
4/14/00
900
1.71
0.21
4/14/00
1445
1.52
0.19
4/15/00
1630
1.38
0.09
4/16/00
830
1.71
0.13
4/17/00
845
1.67
0.09
4/18/00
1345
1.4
-
4/19/00
1245
1.64
0.09
4/20/00
830
1.65
0.09
4/21/00
1030
4.27
0.09
4/22/00
930
1.41
0.08
4/23/00
1000
1.50
0.11
4/24/00
900
1.53
0.12
4/24/00
1000
1.52
0.60
4/24/00
1200
1.44
0.06
4/24/00
1500
1.56
0.09
4/24/00
2100
1.76
0.09
4/25/00
300
1.42
0.07
4/25/00
900
1.45
0.09
4/25/00
1500
1.48
0.06
4/25/00
2100
1.47
0.08
4/26/00
300
1.47
0.07
4/26/00
900
1.49
0.11
From the Table 4-12 data, it is obvious that the multimedia filter in the test unit substantially reduced
particulate material in the feedwater.
43
-------
Table 4-13. Bench-Top Turbidity Data Summary (April 12- April 26,2000)
Feed (NTU) Filtrate (NTU)
Average 1.66 0.13
Minimum 1.38 0.06
Maximum 4.27 0.60
Standard Deviation 0.57 0.12
95% Confidence Interval 1.43. 1.89 0.08. 0.18
Note that multiple readings for the bench-top turbidity data as required for Task 4 for the period of
April 24 through 26 are included in the graphs as additional data points
On April 21, 2000 the bench-top turbidity reading on the feedwater stream was very high (4.27 NTU
verses an average concentration of 1.66 NTU). On the same date the plant continuous turbidimeter
readings peaked at 2.24 NTU (as compared to an average of 1.51 NTU). Also on April 21, 2000, the
total arsenic concentration in the feedwater stream peaked at 146 |j,g/L (verses an average
concentration of 77.6 |_ig/L), The insoluble arsenic in this stream is approximately 106 |j,g/L (146-
40.1). From the above, it is apparent that a disturbance in the tunnel created the turbidity spike which
carried out additional arsenic, probably complexed with ferric hydroxide in the insoluble complex.
Figure 4-7. Daily Bench-Top Turbidity Data vs. Time (April 12- April 26,2000)
Turbidity as shown in Figure 4-7 was substantially reduced by the multimedia filter in the Watermark
eVox® Model 5 Coagulation/Filtration System. The April 21, 2000, turbidity spike had no effect on
the filtrate turbidity reading for that day.
44
-------
Table 4-14 shows the daily measurements for dissolved oxygen.
Table 4-14. Daily Dissolved Oxygen Data (mg/L) (April 12- April 26,2000)
Date Time Feedwater (mg/L) Filtrate (mg/L)
4/12/00
1900
6.71
6.28
4/13/00
1135
6.42
5.72
4/14/00
900
5.66
6.14
4/14/00
1445
5.53
5.59
4/15/00
1630
6.19
6.12
4/16/00
830
5.26
5.81
4/17/00
845
5.54
5.77
4/18/00
1345
5.07
5.32
4/19/00
1245
5.29
5.76
4/20/00
830
5.51
5.37
4/21/00
1030
5.75
6.23
4/22/00
930
5.66
5.77
4/23/00
1000
5.31
6.16
4/24/00
900
6.02
6.02
4/24/00
1000
5.63
6.21
4/24/00
1200
5.84
5.67
4/24/00
1500
6.35
6.75
4/24/00
2100
5.90
6.37
4/25/00
300
5.66
5.72
4/25/00
900
6.48
5.91
4/25/00
1500
6.54
6.68
4/25/00
2100
5.80
5.65
4/26/00
300
6.48
7.02
4/26/00
900
6.27
6.42
Table 4-15. Daily Dissolved Oxygen Data Summary (April 12 —
April 26,2000)
Feed (mg/L)
Filtrate (mg/L)
Average
5.87
6.02
Minimum
5.07
5.32
Maximum
6.71
7.02
Standard Deviation
0.46
0.43
95% Confidence Interval
5.68,6.06
5.84, 6.19
Note that multiple readings for the dissolved oxygen data as required for Task 4 for the period of April
24 through 26 are included in the graphs as additional data points.
45
-------
Figure 4-8. Daily Dissolved Oxygen Data vs. Time (April 12- April 26,2000)
There does not appear to be substantial differences in dissolved oxygen concentration between
feedwater and filtrate streams.
4.3.2 Task 2 - Feed and Finished Water Quality Characterization
Continuous turbidity data from the wall-mounted plant turbidimeter on the feedwater stream, and from
the Watermark turbidimeter on the filtrate stream (Appendix E) are summarized in Table 4-16 and
plotted in Figure 4-9. On-line feedwater turbidity readings during the testing period averaged 1.51
NTU, compared to the bench-top turbidity average of 1.66 NTU. The on-line filtrate turbidity readings
for the testing period averaged 0.060 NTU, compared to the bench-top average of 0.13 NTU. The
Watermark filtrate turbidimeter was shut down for repair parts of each of the days of April 18, 19 and
24.
Table 4-16. Continuous Turbidity Data Summary (April 12- April 26,2000)
Feed (NTU) Filtrate (NTU)
Average
1.51
0.059
Minimum
0.99
0.018
Maximum
2.55
0.455
Standard Deviation
0.37
0.097
95% Confidence Interval
1.44,1.57
0.042,0.077
46
-------
Feedwater(NTU) Filtrate (NTU)
Figure 4-9. Continuous Turbidity vs. Time (April 12- April 26, 2000)
Based on the average turbidity data from Table 4-16, feedwater turbidity was reduced by 96% by the
Watermark eVox® Model 5 Coagulation/Filtration System. Although aberrations in turbidity
measurements in the filtrate stream are expected to be minimal, the accuracy of the on-line turbidimeter
data on the low readings in the filtrate stream is called into question and addressed in Section 4.5.3.3.
Table 4-17. Iron Concentrations (April 21 - April 26,2000)
Date Time Feedwater Iron (mg/L) Filtrate Iron (mg/L)
4/21/00
1030
0.756
0.0216
4/22/00
0930
0.244
0.0233
4/23/00
0910
0.225
<0.02
4/24/00
0900
0.231
<0.02
4/24/00
1000
0.235
<0.02
4/24/00
1200
0.343
<0.02
4/24/00
1500
0.25
<0.02
4/24/00
2100
0.286
<0.02
4/25/00
0300
0.236
<0.02
4/25/00
0900
0.238
<0.02
4/25/00
1500
0.358
<0.02
4/25/00
2100
0.234
<0.02
4/26/00
0300
0.275
<0.02
4/26/00
0900
0.26
<0.021
47
-------
Table 4-18. Iron Data Summary (April 21-
April 26,2000)
Feedwater (mg/L)
Filtrate (mg/L)
Average
0.298
0.020
Minimum
0.225
0.02
Maximum
0.756
0.0233
Standard Deviation
0.138
0.001
95% Confidence Interval
0.226, 0.370
0.020,0.021
*A11 readings at the MDL for Arsenic III (0.02 mg/L) were used as that number in calculations.
It is apparent from Table 4-18 that the Watermark System has removed almost all of the iron in the
feedwater, even though FeCl, was injected as a coagulant.
On a daily basis, samples were taken and the laboratory measured the concentrations of the alkalinity
and antimony. Tables 4-19 and 4-20 list the raw data and provide a summary of the alkalinity, and
Figure 4-10 is a plot of alkalinity data over the test period.
Table 4-19. Alkalinity Daily Measurements (April 12- April 26,2000)
Date Time Feedwater (mg/L) Filtrate (mg/L)
4/13/00
1135
146
137
4/14/00
1445
142
137
4/15/00
1345
144
137
4/16/00
1000
145
137
4/17/00
1400
144
135
4/18/00
900
141
138
4/19/00
1130
146
137
4/20/00
830
142
148
4/21/00
1030
146
140
4/22/00
930
144
137
4/23/00
900
144
137
4/24/00
900
145
136
4/24/00
1000
143
144
4/24/00
1200
144
138
4/24/00
1500
144
139
4/24/00
2100
144
136
4/25/00
300
147
139
4/25/00
900
145
137
4/25/00
1500
146
137
4/25/00
2100
144
136
4/26/00
300
145
138
4/26/00
900
144
139
Table 4-20. Alkalinity Data Summary (April 12
- April 26,2000)
Feedwater (mg/L)
Filtrate (mg/L)
Average
144
138
Minimum
141
135
Maximum
147
148
Standard Deviation
1.5
2.9
95% Confidence Interval
144, 145
137,139
48
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The multiple readings for the alkalinity data as required for Task 4 for the period of April 24 through 26
are included in the tables and graph as additional data points.
Date
—•— Feedwater —o— Filtrate
Figure 4-10. Alkalinity vs. Time (April 12- April 26, 2000)
Although the average alkalinity measurement of the filtrate stream is approximately 4% less than the
feedwater stream, it is apparent that alkalinity is not effectively removed by this technology.
Antimony data generated during the testing are listed in the following tables and graph. Table 4-21 lists
the daily measurements for antimony for the verification testing period.
Table 4-21. Antimony Daily Measurements (April 12-
Date Time
April 26,2000)
Feedwater (|ig/L)
Filtrate (ng/L)
4/13/00
1135
9.2
9.0
4/14/00
1445
8.9
8.4
4/15/00
1345
8.9
8.5
4/16/00
1000
9.4
8.4
4/17/00
1400
9.4
9.1
4/18/00
900
9.3
8.9
4/19/00
1130
9.4
8.7
4/20/00
830
9.4
9.1
4/21/00
1030
9.2
8.7
4/22/00
930
9.1
9.0
4/23/00
900
9.4
8.9
4/24/00
900
8.9
8.5
4/24/00
1000
8.9
8.8
4/24/00
1200
9.3
8.7
4/24/00
1500
9.0
8.5
4/24/00
2100
8.9
8.5
4/25/00
300
8.8
8.4
4/25/00
900
8.8
8.5
4/25/00
1500
8.7
8.5
4/25/00
2100
9.0
8.6
4/26/00
300
9.0
8.6
4/26/00
900
9.1
8.7
49
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Table 4-22. Antimony Data Summary (April 12-
April 26,2000)
Feedwater (jag/L)
Filtrate (jag/L)
Average
9.1
8.7
Minimum
8.7
8.4
Maximum
9.4
9.1
Standard Deviation
0.2
0.2
95% Confidence Interval
9.0, 9.2
8.6, 8.8
The multiple readings for the antimony data as required for Task 4 for the period of April 24 through 26
are included in the tables and graph as the additional data points.
Date
—I— Feedwater —o— Filtrate
Figure 4-11. Antimony vs. Time (April 12- April 26,2000)
From the above data, it is evident that, although there is a slight reduction, antimony is not effectively
removed by this process.
Sample measurements for Arsenic (Total, Dissolved, HI, and V) for the testing period are listed below
in Table 4-23.
50
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Table 4-23. Arsenic Data Measurements (April 12- April 26,2000)
Total As (ng/L)
Dissolved As (pg/L)
As (III) ((-ig/L)
As (V) (ng/L)
Date
Time
Feedwater
Filtrate
Feedwater
Filtrate
Feedwater
Filtrate
Feedwater
Filtrate
4/13/00
1135
73.8
1.8
40.4
1.8
2.5
<0.5*
37.9
1.3
4/14/00
1445
60.9
1.2
37.4
1.7
2.2
<0.5*
35.2
1.2
4/15/00
1345
66.8
1.3
40.1
1.7
2.2
<0.5*
37.9
1.2
4/16/00
1000
74.8
1.3
42
1.6
2.4
<0.5*
39.6
1.1
4/17/00
1400
82.7
1.4
40.1
2
2.4
<0.5*
37.7
1.5
4/18/00
900
65.3
1.2
37.8
1.4
2.3
<0.5*
35.5
0.9
4/19/00
1130
87.2
1.3
40
1.7
2.1
<0.5*
37.9
1.2
4/20/00
950
80
34.5
40.8
32.6
2.8
1
38
31.6
4/21/00
1030
146
1.7
40.1
2.1
2.7
0.9
37.4
1.2
4/22/00
930
73.7
25.2
40.3
21.9
3.2
0.9
37.1
21
4/23/00
910
75.1
1.7
41.8
2.2
2.7
0.9
39.1
1.3
4/24/00
900
69.8
1.8
40.6
2.2
2.5
0.8
38.1
1.4
4/24/00
1000
71.8
1.9
43
2.3
3
0.9
40
1.4
4/24/00
1200
89.4
1.6
42.6
2.1
3.6
0.9
39
1.2
4/24/00
1500
72.7
1.5
42.9
1.9
3
0.9
39.9
1
4/24/00
2100
76.6
2
43.5
2.6
2.6
0.8
40.9
1.8
4/25/00
300
70.2
1.4
45.4
3.2
2.4
1
43
2.2
4/25/00
900
70.6
1.4
45.8
3.4
2.2
<0.5*
43.6
2.9
4/25/00
1500
84.7
1.3
43
3.5
2.4
<0.5*
40.6
3
4/25/00
2100
69.6
1.8
45.9
3.7
2.1
<0.5*
43.8
3.2
4/26/00
300
71.4
1.3
45.3
3.5
2.1
<0.5*
43.2
3
4/26/00
900
74.1
1.8
45.7
4
2.4
<0.5*
43.3
3.5
* MDL for Arsenic III (<0.5 |ig/L).
Note: the reliability of the low-level data (MDL of 0.5 jag/L to approximately 2|ig/L) should be considered only
qualitative (not quantitative).
Samples tested for Arsenic (Total, Dissolved, IE, and V) in the coagulated feedwater (sample taken
immediately prior to the retention tank) on April 18, 2000 at 0900 are not shown in corresponding
Table 4-24 summary, or graphed in corresponding arsenic Figures 4-12 through 4-15. Data were
collected as an indicator of the process operations and are in addition to the ETV Protocol. These data
are available in Appendix G.
A closer inspection of the dissolved arsenic data in Table 4-23 shows that there is an inconsistency
between the dissolved arsenic results and the total arsenic results shown for the filtrate. The total arsenic
results are all lower than the dissolved arsenic concentrations. This obviously cannot be an accurate
result. The feedwater and concentrate data show in all cases that the total arsenic is higher than the
dissolved arsenic. The concentration in these streams is much higher suggesting that the problem only
occurs at concentrations near the detection limit. This data would suggest that the problem is related to
interference in the analysis at very low concentrations.
Given this inconsistency, the State of Utah laboratory was asked to review the data and attempt to
explain the possible cause of the discrepancy. Their findings are presented in their entirety in Appendix
H. The basic cause of the problem, in their opinion, appears to be that the use of sulfuric acid in the
preservation process for the dissolved arsenic samples causes a positive interference in the ICP-MS
analysis. This positive interference is relatively small (a few tenths of a p.g/1; typically 0.4-0.6 |_ig/l), but at
51
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the low concentrations being measured in the permeate this positive interference is significant. Therefore,
the dissolved arsenic results appear to be biased high. This positive bias results in an understating of the
removal percentage for the dissolved arsenic in the feed water.
The NSF quality control review of the data suggested that a higher quantitation limit maybe more
appropriate for the arsenic analysis. For more information, see Section 4.5.1 of this report.
A slight break in the FeCL3 metering pump discharge line, discovered very early in the morning of April
20, 2000, resulted in some leakage of the FeCl, solution. Although repaired by 0945, the arsenic
samples collected at approximately 0950 show extremely high readings for Total As, Dissolved As and
As(V) in the filtrate stream. These high readings are suspected to be the result of insufficient FeCl,
coagulant chemical injection.
Table 4-24. Arsenic Data Summary (Anril 12- Anril 26.2000)
Feedwater (u.g/L) Filtrate (u.g/L)
Total Arsenic
Average
77.6
4.1
Minimum
60.9
1.2
Maximum
146.0
34.5
Standard Deviation
16.8
8.5
95% Confidence Interval
70.6, 84.6
0.6,7.6
Dissolved Arsenic
Average
42.0
4.7
Minimum
37.4
1.4
Maximum
45.9
32.6
Standard Deviation
2.5
7.5
95% Confidence Interval
41.0, 43.1
1.5,7.8
Arsenic (III)
Average
2.5
0.7
Minimum
2.1
<0.5*
Maximum
3.6
1.0
Standard Deviation
0.4
0.2
95% Confidence Interval
2.4, 2.7
0.6*, 0.8
Arsenic (V)
Average
39.5
4.0
Minimum
35.2
0.9
Maximum
43.8
31.6
Standard Deviation
2.6
7.4
95% Confidence Interval
38.4.40.6
0.9. 7.1
*A11 readings at the MDL for Arsenic III (<0.5 jag/L) were used as that number in calculations.
Note: the reliability of the low-level data (MDL of 0.1 jxg/L to approximately 2|ig/L) should be considered only
qualitative (not quantitative).
Total arsenic readings as required for Task 4 for the period of April 24 through 26 are included in
Figure 4-12 as additional data points.
52
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Figure 4-12. Total Arsenic vs. Time (April 12- April 26,2000)
Based on average total arsenic data in Table 4-24, almost 95% of this contaminant was removed. In
addition, with the exception of 2 readings, all filtrate concentrations of total arsenic were at 2 |j,g/L or
below.
The multiple readings for the dissolved arsenic data as required for Task 4 for the period of April 24
through 26 are included in Figure 4-13 as additional data points
//////////////
Date
H— Feedwater —o— Filtrate
Figure 4-13. Dissolved Arsenic vs. Time (April 12- April 26,2000)
53
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Based on average dissolved arsenic values in Table 4-24, almost 89% of this species was removed by
the Watermark eVox® Model 5 Coagulation/Filtration System. With the exception of 2 data points1,
all of the filtrate readings are at or below 4 |jg/L.
Sample collections for Arsenic m as required for Task 4 during the period of April 24 through 26 are
included in Figure 4-14 as additional data points.
Figure 4-14. Arsenic (IE) vs. Time (April 12- April 26,2000)
Although calculations indicate that 72% removal of As m occurred in this test, the uncertainty
associated with the analytical measurements of concentrations at or below the quantitative detection limit
calls into question the accuracy of this removal percentage.
Sample collection and measurement of Arsenic V as required for Task 4 during the period of April 24
through 26 are included in Figure 4-15.
1 A slight break in the FeCL3 metering pump discharge line, discovered very early in the morning of April 20, 2000, resulted in some
leakage of the FeCl3 solution. Although repaired by 0945, the arsenic samples collected at approximately 0950 show extremely high
readings for Total As, Dissolved As and As(V) in the filtrate stream. These high readings are suspected to be the result of insufficient
FeCl3 coagulant chemical injection.
54
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Date
—•— Feedwater —o— Filtrate
Figure 4-15. Arsenic (V) vs. Time (April 12- April 26,2000)
With the exception of 2 data points2 and based on the average data from Table 4-24, the filtrate
concentration of As V exhibited substantial removal (89.9%). Although it is evident that removal of As
V occurred in this test, the uncertainty associated with the analytical measurements of concentrations, at
or below the quantitative detection limit, such as what was experienced in this test, precludes calculation
of accurate removal percentages.
4.3.3 Task 3: Documentation of Operating Conditions and Treatment Equipment
Performance
The Watermark eVox® Model 5 Coagulation/Filtration System is designed to automatically backwash
based on a preset time interval. For this test, the manufacturer chose a four-hour interval with
backwashing to be initiated at five minutes before the hours of midnight, 4 AM, 8 AM, Noon, 4 PM
and 8 PM every day throughout the duration of the test period.
The actual backwashing sequence involved four minutes of media backwash followed by one minute of
media settling during which no water was flowing.
An audio/visual alarm was connected to the filtrate on-line turbidimeter to be activated when the reading
reached 0.5 NTU. On April 13 at 0746, the alarm went off and the unit was backwashed by push
button initiation. The alarm was reset to activate when the turbidimeter read 0.20 NTU, but was
o
A slight break in the FeCL3 metering pump discharge line, discovered very early in the morning of April 20, 2000, resulted in some
leakage of the FeCl3 solution. Although repaired by 0945, the arsenic samples collected at approximately 0950 show extremely high
readings for Total As, Dissolved As and As(V) in the filtrate stream. These high readings are suspected to be the result of insufficient
FeCl3 coagulant chemical injection.
55
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quickly reset to 0.50 NTU upon observation that it went off too frequently; on five or more occasions,
the alarm went off just after the media settling period as service flow was initiated, but never for more
than a five minute duration. It was determined that there was a small quantity of suspended solids left in
the bottom of the filter vessel which passed out with the filtrate upon initiation of service flow after the
backwash cycle. Programming the system to allow media setting prior to initiation of the service cycle
can eliminate this problem.
The service flow rate of the filter was maintained at an almost constant 1.1 gpm with an operating time
of 235 minutes between backwashing; the total quantity of water processed between backwashing
episodes was 258.5 gallons. As expected, the pressure drop across the media filter increased during
the interval between backwashing episodes, but never exceeded 5.0 psig, except for one reading of 9.5
psig. Table 4-25 is a summary of the pressure drop data over the duration of the test, and Figure 4-16
is a graphical representation. The time of each backwashing episode is also indicated.
The April 20 and 22 data for total arsenic, dissolved arsenic and arsenic (V) in the filtrate stream
indicate unusually high concentrations. The following items were noted from the laboratory (field)
notebook: 1). On April 20 at 0130 a leak in the FeCK metering pump discharge was noticed and the
hole was covered by tape. At 0940, the FeCK solution was observed to be leaking slightly around the
tape, so the tubing was cut at that point and reinserted into the discharge side of the pump. Analytical
samples were taken at 0950. It is possible that an insufficient concentration of FeCK solution was fed
into the system during that time. 2). On April 22, 2 batches of FeCK solution and 1 batch of Q2
solution were added to the feed tanks at 0830, however, there was no evidence that either solution had
run out prior to this activity.
When total arsenic is compared to dissolved arsenic in table 4-24 an average of 54% of the total
arsenic in the feedwater was dissolved. Additionally, from the same table, it can be calculated that an
average of 94% of the dissolved arsenic in the feedwater was in the arsenic (V) form. Because of the
relative ease of oxidation of arsenic (m) to arsenic (V) and the presence of chlorine (an oxidizer) in the
coagulation process, it is expected that most of the arsenic (in) was oxidized to arsenic (V) prior to the
filtration step.
Table 4-25. Pressure Drop Data Summary (April 12 - April 26,2000)
AP (psig)
Average
2.7
Minimum
0.5
Maximum
9.5
Standard Deviation
1.1
95% Confidence Interval
2.5,2.9
Figure 4-16 shows the hours of operation, starting with the initiation of coagulation feed, and noting
instantaneous pressure drop and backwash episodes.
56
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Figure 4-16. Pressure Drop vs. Run Time (April 12- April 26,2000)
With one exception (205.5 hours into the ran), the pressure drop across the filter bed was maintained at
5 psig or less.
Backwashing with raw water was performed at a rate of 20 gpm/ft2 of bed surface area for four minutes
every four hours. Based on the fact that 258.5 gallons of water were processed between backwashing
episodes, each of which utilized 16 gallons of backwash water, water recovery can be calculated by the
following formula:
Vo recovery = -
258.5-16
258.5
xl00 = 93.8% recovery
4.3.4 Task 4: Arsenic Removal Results
The Test Plan required that samples be collected from both the feedwater and filtrate streams for
analyses of speciated arsenic in particular. Samples were collected at time zero and at 1, 3, 6 hours and
every six hours thereafter for a total of 48 hours. In addition to arsenic, the samples were analyzed by
the Laboratory for the following parameters: Alkalinity; Algae (Chlorophyll A); Iron and Antimony.
Results are presented in table 4-26.
57
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Table 4-26. Task 4 Arsenic Data Summary (April 24- April 26,2000)
Total As (|xg/L)
Dissolved As (|xg/L)
As (III)*
: (Hg/L)
As (V) (ng/L)
Feedwater
Filtrate
Feedwater
Filtrate
Feedwater
Filtrate
Feedwater
Filtrate
Average
74.6
1.6
44.0
2.9
2.6
0.7
41.4
2.2
Minimum
69.6
1.3
40.6
1.9
2.1
<0.5*
38.1
1
Maximum
89.4
2.0
45.9
4
3.6
1.0
43.8
3.5
Std. Dev.
6.6
0.3
1.7
0.7
0.5
0.2
2.0
0.9
95% CI
70.8, 78.5
1.5,1.8
42.9,45.0
2.5, 3.4
2.3,2.8
0.6, 0.8
40.2,42.6
1.7,2.8
*A11 readings at the MDL for Arsenic III (<0.5 |xg/L) were used as that number in calculations.
Note: the reliability of the low-level data (MDL of 0.1 |xg/L to approximately 2 |xg/L) should be considered only
qualitative (not quantitative).
Because the Watermark eVox® Model 5 Coagulation/Filtration System ran continuously and the Task
4 activity involved only more frequent sampling than during the previous portion of the testing, it is not
surprising that most of the analytical results are very close to those obtained over the whole testing
period, during the Task 2 activity (Section 4.3.2) and summarized in Table 4-24. The filtrate stream
readings of total arsenic and dissolved arsenic in Table 4-26 would show much closer agreement to
those in Table 4-24 if the readings for the data of 4/20/00 and 4/22/00 are not included. These data
are suspected to be the result of either a leak in the FeCl, feedline or mislabeled sample containers. In
addition, the reliability of all filtrate readings near the MDL is called into question, as explained in
Section 4.3.2.
Figures 4-17 through 4-20 are plots of each arsenic species for Task 4 activities.
1200 1 500 21 00 300 900 1 500 21 00 300 900
4/24/00 4/24/00 4/24/00 4/25/00 4/25/00 4/25/00 4/25/00 4/26/00 4/26/00
Date & Time
H— Feedwater —o— Filtrate
Figure 4-17. Task 4 Total Arsenic vs. Time (April 24- April 26,2000)
58
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50
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£ 30
C
o
o
(A
b
20
10
900 1000 1200 1500 2100 300 900 1500 2100 300 900
4/24/00 4/24/00 4/24/00 4/24/00 4/24/00 4/25/00 4/25/00 4/25/00 4/25/00 4/26/00 4/26/00
Date & Time
¦ Feedwater
¦Filtrate
Figure 4-18. Task 4 Dissolved Arsenic vs. Time (April 24-April 26,2000)
Feedwater —o—Filtrate
Figure 4-19. Task 4 Arsenic (III) vs. Time (April 24- April 26,2000)
59
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0
900 1 000 1200 1500 21 00 300 900 1500 21 00 300 900
4/24/00 4/24/00 4/24/00 4/24/00 4/24/00 4/25/00 4/25/00 4/25/00 4/25/00 4/26/00 4/26/00
Date & Time
—•—Feedwater —o—Filtrate
Figure 4-20. Task 4 Arsenic (V) vs. Time (April 24- April 26,2000)
Results for samples analyzed by the Laboratory for the Alkalinity, Algae (Chlorophyll A); Iron and
Antimony are shown in Table 4-27.
Table 4-27. Task 4 Analytical Data Summary for Antimony, Alkalinity, Chlorophyll A and Total Iron (April 24-
April 26,2000)
Antimony (ng/L) Alkalinity (mg/L) Chlorophyll A (ng/L) Total Iron (mg/L)*
Feedwater Filtrate Feedwater Filtrate Feedwater Filtrate Feedwater Filtrate (prior to
FeCl3 addition)
Average
8.9
8.6
145
138
0.6
0.3
0.268
0.02
Minimum
8.7
8.4
143
136
0.3
0.3
0.231
<0.02
Maximum
9.3
8.8
147
144
0.8
0.3
0.358
0.021
Std. Dev.
0.2
0.1
1
2
0.4
0.0
0.045
0.00
95% Confidence
8.8, 9.0
8.5, 8.6
144,145
137,140
0.1, 1.0
NA
0.241,0.294
NA
Interval
*A11 readings for Total Iron at the MDL (0.02 mg/L) were used at that number in calculations.
NA because Standard Deviation = 0
The test indicated that antimony is not removed by the system.
Alkalinity was slightly removed (4.8% reduction from feedwater to filtrate on average), which may be
attributed to the slight reduction in pH from feedwater to filtrate, as well as the addition of sodium
hypochlorite to the feedwater.
60
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Chlorophyll A concentrations were expected to be minimal in the feedwater because it is groundwater.
Chlorophyll concentrations in the feedwater and filtrate streams were identical over the entire test, with
one exception, a reading of 0.8 |j,g/L on 4/26/00.
Total iron concentrations in the feedwater streams were removed to the MDL in the filtrate stream.
Table 4-28 provides a summary of Task 4 testing results for temperature, pH and total chlorine.
Table 4-28. Task 4 Analytical Data for Temperature, pH and Chlorine (April 24- April 26,2000)
Temperature (°C) pH Total Chlorine (mg/L)
Feedwater Filtrate Feedwater Filtrate Feedwater Filtrate
Average
9.6
10.5
7.33
7.22
1.61
Minimum
9.3
9.8
7.29
7.17
1.42
Maximum
9.9
10.7
7.38
7.37
1.82
Std. Dev.
0.1
0.3
0.03
0.06
0.12
95% Confidence
9.6, 9.7
10.3,10.7
7.31,7.34
7.19,7.26
1.54,1.68
Interval
- = No reading was taken
The filtrate temperature averages less than 0.1 C higher than the feedwater temperature. This increase
apparently the result of the residence time of the water in the treatment system located inside a heated
building.
The pH of the filtrate stream averaged slightly more than 0.01 unit less than that of the feedwater stream.
This slight reduction is probably due to the addition of ferric chloride coagulant, which is acidic.
Chlorine, in the form of sodium hypochlorite, was added to the feedwater to oxidize all As (m) to As
(V). Table 4-28 is a summary of the residual chlorine in the filtrate stream after oxidization.
Table 4-29 summarizes all of the turbidity readings for the feedwater and filtrate streams.
Table 4-29. Task 4 Analytical Data Summary for On-line Turbidity and Bench-Top Turbidity (April 24- April 26,
2000)
On-line (Continuous) Turbidity (NTU) Bench-Top Turbidity (NTU)
Feedwater Filtrate Feedwater Filtrate
Average
1.18
0.021
1.51
0.13
Minimum
0.99
0.019
1.42
0.06
Maximum
1.66
0.025
1.76
0.60
Std. Dev.
0.16
0.002
0.09
0.16
95% Confidence Interval
1.12, 1.25
0.020,0.021
1.45,1.56
0.04, 0.22
Turbidity readings were made with both on-line (continuous) turbidimeters and a manual bench-top
turbidimeter. There was fairly close agreement between the on-line and bench-top instruments on the
feedwater turbidity data; however, a substantial difference between the two on the filtrate stream data.
An explanation for this is offered in QA/QC Results, Section 4.5.3.3. Table 4-29 does illustrate that
turbidity is significantly reduced by this system.
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Table 4-30 shows the Dissolved Oxygen measured during Task 4 activities.
Table 4-30. Task 4 Dissolved Oxygen Data (April 24- April 26,2000)
Feedwater (mg/L) Filtrate (mg/L)
Average
6.09
6.22
Minimum
5.63
5.65
Maximum
6.54
7.02
Std. Dev.
0.35
0.47
95% Confidence Interval
5.88,6.29
5.94, 6.50
Table 4-30 indicates that this system had no significant effect on the dissolved oxygen concentration in
the feedwater stream.
Table 4-31 shows the miscellaneous parameters that were measured by the State of Utah Laboratory
as part of Task 4 activities.
Table 4-31. Task 4 Analytical Data - Miscellaneous Parameters (April 24 - April 26,2000)
Date
Time
Parameter
Units
Feedwater
Filtrate
4/24/00
0900
TOC
mg/L
<0.5*
<0.5
4/26/00
0900
TOC
mg/L
<0.5*
<0.5
4/24/00
0900
UV254 Absorbance
cm"1
0.007
0.006
4/26/00
0900
UV254 Absorbance
cm"1
0.005
0.007
4/24/00
0900
Hardness*
mg/L
443
439
4/26/00
0900
Hardness
mg/L
441
446
4/24/00
0900
Aluminum
mg/L
<0.030**
<0.030**
4/26/00
0900
Aluminum
mg/L
<0.030**
<0.030**
4/24/00
0900
Manganese
mg/L
0.0134
<0.0050**
4/26/00
0900
Manganese
mg/L
0.0163
<0.0050**
4/24/00
0900
Sulfate
mg/L
277.0
272
4/26/00
0900
Sulfate
mg/L
281.0
273.0
4/26/00
0900
Silica (total)
mg/L
19.6
19.7
4/26/00
0900
Silica (dissolved)
mg/L
19.3
19.1
* Hardness calculated from laboratory readings of calcium and magnesium using SM for the Analysis of Water and
Wastewater (18th Ed, Method 2340B)
** Sample reported below the MDL.
As an indication of the extremely low organic content of this water, Total Organic Carbon (TOC)
measurements were below the detection limit and UV254 Absorbance data were very low.
Hardness and sulfate parameters appeared to be unaffected by the coagulation/filtration process;
aluminum levels were below the detection limit in both the feedwater and filtrate streams, and
manganese appears to have precipitated out, more than likely as manganese hydroxide.
Since the concentration of manganese in the feedwater was less than 10% of the iron concentration,
manganese probably had little or no effect on arsenic removal. The iron present in the feedwater was of
sufficient concentration to react with the arsenic, particularly in the presence of chlorine, which oxidized
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the iron to the ferric form. The addition of ferric chloride ensured that there would be an excess of iron
to complete the coagulation process.
From Table 4-31, it is evident that neither total or dissolved silica concentrations were affected by the
Watermark system.
4.4 Results of Equipment Characterization
During the verification testing, the factors associated with the qualitative, quantitative and cost
characteristics of the Watermark eVox® Model 5 Coagulation/Filtration System were identified, within
the limits of the short duration of the test.
4.4.1 Qualitative Factors
The qualitative factors examined were the susceptibility of the equipment to environmental condition
changes, operational reliability and equipment safety.
4.4.1.1 Susceptibility to Changes in Environmental Conditions
Changes in environmental conditions that cause changes in feedwater quality can affect the performance
of coagulation/filtration systems.
The optimum performance of any coagulant chemistry is a function of many chemical and environmental
variables such as pH, temperature, ORP level and any chemical constituents which might interfere with
the formation of the ferric hydroxide/arsenic complex. This has resulted in the requirement for the Initial
Operations period of the verification testing program wherein the coagulant chemistries and dosages
were optimized.
Since the source was groundwater, even though ambient conditions were changing, the feedwater
temperature remained relatively unchanged throughout the test. Also, the equipment was located
indoors, so it was unaffected by weather changes.
4.4.1.2 Operational Reliability
The equipment ran continuously throughout the duration of the test, with only a 50-minute interruption
for feed pump replacement on April 14, 2000. On April 20, 2000, a pinhole leak occurred in the FeCl,
discharge tubing line from the metering pump. This was quickly repaired (refer to Section 4.3.2 for
more detail).
Once flows, pressures and backwash conditions were established during the Initial Operations period,
no adjustments were made throughout the duration of the test.
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4.4.1.3 Equipment Safety
Evaluation of the safety of the treatment system was done by examination of the components of the
system and identification of hazards associated with these components. A judgment as to the safety of
the treatment system was made from these evaluations.
There are safety hazards associated with electrical service and pressurized water. The electrical service
was connected by a qualified electrical contractor according to local code requirements and did not
present an unusual safety risk. Based on the pressure data recorded during the test, the water pressure
inside the treatment system was relatively low (<40 psi) and did not present an unusual safety risk. (See
Appendix G).
The coagulation chemicals, sodium hypochlorite and ferric chloride, are considered hazardous;
however, safe handling procedures (as outlined in the MSDS) were followed when replenishing the feed
tanks and no problems were encountered.
No injuries or accidents occurred during the testing.
4.4.2 Quantitative Factors
Quantitative Factors examined during the verification testing were power, consumables, waste disposal
and length of operating cycle.
4.4.2.1 Electrical Power
The electrical power used was 110VAC, single phase, 20A service. The power was recorded on an
Amprobe Kilowatt/Hour Meter (non-demand). The total power consumed was 359 kWh.
4.4.2.2 Consumables
• Total quantity of filtrate produced:
1.1 gpm x 60 min/hr x 352.5 hr = 23, 265 gallons.
• Total quantity of sodium hypochlorite consumed:
0.005 gph x 328.5 hr = 1.64 gallons of 0.42% bleach = 0.13 gallons of 5.25% bleach.
1.64 x 0.0042 = 0.0069 gallons (100% NaOCl basis) 23,265 gallons of filtrate = 3 x
10 7 gallons of 100% sodium hypochlorite per gallon of filtrate produced.
• Total quantity of ferric chloride consumed:
0.094 gph x 328.5 = 30.879 gallons of 0.7% FeCl, = 0.67 gallons of 32.5% FeCl,
30.879 x 0.007 = 0.22 gallons (100% FeCl, basis) 21,681 gallons of filtrate = 1 x 10"
5 gallons of 100%) FeCl, per gallon of filtrate produced.
The above data do not include the water, ferric chloride and sodium hypochlorite directed to the drain in
order to maintain the optimum feed pump pressure.
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4.4.2.3 Waste Disposal
The waste generated during the verification testing period was the backwash stream at approximately
16 gallons per episode. Since the system backwash was activated by a timer set for four (4) hour
intervals and the total test period was 352.5 hours, a total of 88 backwashes occurred, producing a
total volume of 1408 gallons. Because it is not representative of the operating characteristics of a
treatment system used in an actual drinking water application, the excess feedwater flow discussed
above is not included in the above calculation.
The backwash effluent collection tank was equipped with a level oontrol and timer that allowed the
precipitate to settle into an approximate 1,500-gallon reservoir at the bottom of the tank prior to
automatically pumping the supernatant liquid out and to the Snyderville Sewer Improvement District for
discharge. The settling time allowed for each backwashing episode was two hours. Over the total test
period (352.5 hours), a total of 18.9 L of a 1% sludge was collected, equivalent to 2.1 x 10 6 gallons of
sludge (100% basis) per gallon of filtrate.
4.4.2.4 Length of Operating Cycle
The four-hour automatic backwash cycle was the primary determinant of operating run length. With
one exception, at the beginning of the test, all backwashing episodes were initiated by the four-hour
timer.
4.5 QA/QC Results
The objective cf this task is to assure the high quality and integrity of all measurements of operational
and water quality parameters during the ETV project. QA/QC verifications were recorded in the
laboratory logbooks. The results of QA/QC verification performed on on-line instrumentation, hand-
held instruments and the analytical Laboratory are presented below, and a detailed discussion of the
QA/QC procedures and apparent discrepancies is in Appendix H.
4.5.1 Arsenic Speciation and Analysis
On a daily basis, feed, concentrate and permeate samples were collected and speciated on-site. All
samples were then delivered to the State Laboratory for analysis. The laboratory analyzed for total
arsenic, dissolved arsenic and As(III). As(V) data were obtained by subtracting As(m) readings from
the dissolved arsenic figure.
In almost all permeate samples, the dissolved arsenic figures were higher than the total arsenic figures.
The State Laboratory investigated this anomaly in detail and postulates that the presence of 1he H2S04
preservative in bottle b (bottles a and c had HN03 preservative) affected the accuracy of the ICP-MS
analytical equipment. This explanation, arsenic speciation protocol and Laboratory QA/QC procedures
are detailed in Appendix H.
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The Quality Control review by NSF raised the question of whether or not the laboratory could actually
document a reporting limit of 0.5 mg/L for total arsenic, dissolved arsenic and the arsenic species. The
reviewer indicated that in the review comments that sulfate interference had not been proven in his
opinion. It was also stated that a reporting limit (actual quantitation limit) is typically 10 - 30 times the
MDL. Therefore, a reporting of limit of 3 - 5 mg/L maybe more appropriate. At this level, all of the
data would be reported as "less than values" for the filtrate and the difference between the total and
dissolved arsenic would be eliminated.
4.5.2 Data Correctness
Data correctness refers to data quality, for which there are four indicators:
• Representativeness
• Statistical Uncertainty
• Accuracy
• Precision
Calculation of all of the above data quality indicators was outlined in the Chapter 3, Methods &
Procedures. All water quality samples were collected according to the sampling procedures specified
by the EPA/NSF ETV protocols, which ensured the representativeness of the samples.
4.5.2.1 Representativeness
Operational parameters graphs and discussions are included under Task 3 - Documentation of
Operations Conditions and Treatment Equipment Performance. Testing equipment verification is
presented below in discussions in Daily QA/QC Results and Results of QA/QC Verification At The
Start Of Each Testing Period.
4.5.2.2 Statistical Uncertainty
Ninety-five percent confidence intervals were calculated for the water quality parameters of the
Watermark eVox® Model 5 Coagulation/Filtration System as presented in the water sample summary
tables in the discussion of Task 2 - Feed and Finished Water Quality Characterization.
4.5.2.3 Accuracy
For this ETV study, accuracy refers to the difference between the sample result and the true or
reference value. Calculations of data accuracy were made to ensure the accuracy of the testing
equipment in this study. Accuracy of testing equipment verification is presented below in discussions on
Daily QA/QC Results and Results of QA/QC Verification At The Start Of Each Testing Period.
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4.5.2.4 Precision
Precision is a measure of the degree of consistency from test to test, and can be measured by
replication. For single reading parameters, such as pressure and flow rates, precision was ensured by
redundant readings from operator to operator. Calibration procedures for those on-site parameters
consequential to the testing (bench-top turbidity and pH) are presented in discussions on Daily QA/QC
Results and Results of QA/QC Verification At The Start Of Each Testing Period.
4.5.3 Daily QA/QC Results
The on-line feedwater turbidity readings were checked daily against the bench-top turbidimeter. The
readout from the HF Scientific, Inc., Micro 200 on-line influent turbidity averaged 1.51 NTU during the
verification period of April 12 through April 26, 2000; the average from the Hach 21 OOP benchtop
turbidimeter was 1.66 NTU. The discrepancy between the two turbidimeters (on-line and benchtop) of
1.51 NTU and 1.66 NTU is acceptable and within limits (further discussions in Section 4.5.3.3).
The on-line filtrate turbidity readings were checked daily against the bench-top turbidimeter. The
readout from the Hach Model 1720D on-line influent turbidity averaged 0.060 NTU during the
verification period of April 12 through April 26, 2000; the average from the Hach 21 OOP benchtop
turbidimeter was 0.13 NTU. This discrepancy is further explained in Section 4.5.3.3.
The pH meter was calibrated daily against NIST-traceable pH buffers at 7.00 and 10.00 daily. The pH
meter was a Cole Palmer Oaktron® WD-35615 Series. The pH calibration buffers were Oakton pH
Singles 7.00 (model #35653-02), and pH Singles 10.00 (model #35653-03). pH was measured from
filtrate and feedwater water sample tap.
4.5.4 Results Of QA/QC Verifications At The Start Of Each Testing Period
4.5.4.1 Tubing
The tubing and all water lines used on the treatment system were inspected before verification testing
began (April 11, 2000). The tubing and lines were good condition and replacements were not
necessary. Documentation of this activity was inadvertently omitted from the Laboratory Notebook.
The tubing associated with the in-line plant turbidimeters were inspected with every calibration by the
personnel of the water treatment plant.
4.5.4.2 Thermometer
Temperatures were measured in accordance with SM 2550, on the feed and filtrate streams, with a
Radio Shack model No. 63- 1009A digital indoor-outdoor thermometer. This instrument read in 0.1°C
increments and was calibrated by the State of Utah Laboratory as well as in an ice bath and against a
NIST-traceable Thermometer (Tel-Tru model 0054-5).
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4.5.4.3 Turbidimeters
Both on-line and bench top turbidimeters were used during the Watermark eVox® Model 5
Coagulation/Filtration System ETV test.
Two on-line turbidimeters were utilized:
1) A wall mounted HF Scientific, Inc., Micro 200 turbidimeter was used to continuously measure
turbidity of the feedwater. This instrument was cleaned and calibrated at the beginning of the
verification testing period by Spiro Water Tunnel Filtration Plant personnel with standards of 0.01,
0.10, 10.0 and 100.0 NTU, and then cleaned and calibrated weekly, or after a significant turbidity
spike.
2) A Hach Model 1720D turbidimeter purchased new for this test, mounted on the filtrate stream, and
calibrated initially and weekly with standard solutions of 0.04, 0.40 and 4.0 NTU.
A new Hach 21 OOP turbidimeter was utilized to measure grab samples of both feedwater and filtrate at
least once per day. The instrument calibration was verified on March 15, 2000, with primary standards
of 800, 100, 20 and <0.1 NTU, weekly with secondary standards measuring 526, 52.2, 4.87 NTU,
and with another secondary standard of 0.4 NTU with every use.
Discrepancies between the on-line and bench-top instruments were noted, particularly in the filtrate
samples, as indicated in Table 4-29. Several explanations for these are offered which include:
1) Difference in the analytical techniques between the on-line and bench-top turbidimeters:
The bench-top turbidimeter uses a glass cuvette to hold the sample; this cuvette can present some
optical difficulties for this instrument. The on-line turbidimeter has no cuvette to present a possible
interference with the optics of the instrument. The low level of turbidity can create analytical
difficulties, particularly for the bench-top/ Manufacturer's specifications state that stray light
interference is less than 0.02 NTU. Stray light nterference approaching this level at the low
turbidity levels tested could account for the differences in the readings.
2) Geologic activity in the Spiro Tunnel caused short-term turbidity spikes in the feedwater, which may
have affected the accuracy of the on-line plant turbidimeter between routine cleanings. For
example, a turbidity spike occurred at 0300 on April 2, 2000, which shut the filtration plant down
(the alarm/shutdown turbidity level was set at 5.0 NTU). The turbidimeter was cleaned and
returned to service.
3) Although attempts were made to collect bench-top turbidity samples at the same time that on-line
turbidimeter readings were made, the logistics of the sampling locations resulting in small time
differences may have resulted in slight changes in water quality between these events.
4) During Task 4 activities, when a total of 11 readings were taken in a 48-hour period, the calibration
verification data were recorded with every bench-top turbidimeter reading. In addition, some
calibration verification readings were taken by filling the same cuvette twice and comparing the two
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readings of the same standard solution (0.4 NTU). These data are listed in Table 4-32 and
summarized in Table 4-33.
Table 4-32. Bench-Top Turbidimeter Calibration Verification Data (using 0.4 NTU standard)
Date
Time
Reading (NTU)
4/24/00
0900
0.37
1000
0.36
1200
0.36
1500
0.34
2100
0.35
4/25/00
0300
0.35
0900
0.34
1500
0.30, 0.36 (same cuvette)
2100
0.34, 0.33 (same cuvette)
4/26/00
0300
0.33, 0.30 (same cuvette)
0900
0.31, 0.30 (same cuvette)
Table 4-33. Bench-Top Turbidimeter Calibration Verification Data Summary
Reading (NTU)
Average 0.34
Minimum 0.30
Maximum 0.37
Standard Deviation 0.02
95% Confidence Interval 0.32,0.35
4.5.4.4 True Color
True color was measured in accordance with SM 2120 at 455nm wavelength with a Hach DR2010
spectrophotometer. Altogether 17 samples were measured; the reading varied from -4 to +3 PtCo
color units and seven were negative numbers. The Hach standard solution (500 PtCo color units) was
diluted with ultrapure water to produce a solution that should read 1.0 PtCo color units; however,
readings on this aliquot varied from -2 to 1.0. The same results were obtained when both ultrapure
water and distilled water were tested alone. The conclusions drawn from the above were:
1) The Hach DR2010 unit cannot accurately measure color below a level of 2 PtCo color
units.
2) Since the water source is groundwater and low in organics, the true color is expected to be
very low, and in this case, below the accuracy of the instrument.
Further evidence of the low organics concentration is supplied by the fact that all TOC analyses were
below the minimum detection limit of 0.5 mg/L and all UV254 absorbance readings were below 0.024
units.
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4.5.4.5 Total Chlorine
Total chlorine measurements were made in accordance with SM 4500 on a Hach DR2000
spectrophotometer which was standardized with each set of measurements in accordance with the
Method. The Test Plan required that the total chlorine be measured during Task 4 activities when
samples were collected and other parameters measured. Since the feedwater was unchlorinated, and
chlorine was added during the coagulation process, only the filtrate contained chlorine which was
measured on-site and listed in Table 4-28.
4.5.4.6 Pressure Gauges
The pressure gauge used for this study was a glycerin-filled, NIST-traceable Ametek Model 1980L
Gauge (0-60 psig). The inlet and outlet pressure gauge fittings were equipped with quick-connect
fittings and the above gauge was inserted into these fittings for each reading. The certificate of
calibration for this gauge is located in Appendix F.
4.5.4.7 Metering Pump
On April 26, 2000, at the completion of the testing, the chemical feed pump flow and stroke settings
were verified and documented in the Laboratory Notebook. Flow rates were verified volumetrically
with a graduated cylinder and stopwatch. A 1,000 mL graduated cylinder was used for the pump
injecting coagulant (Ferric Chloride) and the sodium hypochlorite metering pump.
4.5.4.8FlowRates
The "bucket and stopwatch" method for calibrating the flow meters was utilized. Unfortunately, this
activity was not recorded in the Laboratory Notebook.
4.5.5 Off-Site Analysis for Chemical and Biological Samples
QA/QC procedures for laboratory analysis were based on SM, 18th Ed., (APFLA, 1992) and EPA
Methods for Chemical Analysis of Water and Wastes, (EPA, 1995).
4.5.5.1 Organic Parameters, Total Organic Carbon and UV254 Absorbance
Samples for these analyses were collected in glass bottles supplied by the State of Utah Laboratory and
delivered to the Laboratory by COA. Although the Test Plan required only one analysis of these
parameters, two analyses were made of each during the Task 4 activities and are listed in Table 4-27.
4.5.5.2 Algae (Chlorophyll) Samples
Samples were collected in opaque containers supplied by the State Laboratory and kept at 0°C in the
on-site refrigerator prior to delivery to the laboratory.
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4.5.5.3 Inorganic Samples
Inorganic samples were collected, held in the refrigerator at 4°C, and shipped in accordance with SM
3010B and C and 1060 and EPA §136.3, 40 CFR Chapter 1. Proper bottles and preservatives,
where required (iron and manganese for example) were used. Although the travel time was brief,
samples were shipped in coolers at 4°C.
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Chapter 5
References
Adin, A. and Rebhum, M. A model to predict concentration and headloss profiles in filtration. Journal
AWWA, 444-453 (1977).
Amirtharajah, A. "Some theoretical and conceptual views of filtration", American Water Works
Association Seminar Proceedings, American Water Works Association, Denver CO, 21-26 1988.
Amirtharajah, A. and O' Melia, C.R., Coagulation Processes: Destabilization, Mixing and Flocculation,
in Water Quality and Treatment, AWWA, Denver CO. pp. 269-365.
ANSI/AWWA B100-89, AWWA Standard for Filtering Material, American Water Works
Association, Denver, CO, 1989.
American Public Health Association, American Water Works Association, Water Environmental
Federation, Standard Methods for the Examination of Water and Wastewater, 18th Edition,
APHA, AWWA, WEF, Washington D C, 1992.
American Water Works Association, Operational Control of Coagulation and Filtration
Processes, Manual of Water Supply Practices M37, American Water Works Association, Denver,
CO, 1992.
Badger, T.J., Bergemamann, E.P., Smith, P.K., Datta, R. Chromatography Aids in Arsenic Removal,
Water Technology, 66-71 (1999).
Cheng, R.C., Liang, S, Want, H.C., Beuhler, M.D. Enhanced Coagulation For Arsenic Removal
Journal AWWA, 79-90 (1994).
Cleasby, John L. Filtration in Water Quality and Treatment Journal AWWA, 455-560 (1990).
Cleasby, J. L. Williamson, M.M., & Bauman, E.R. Effect of filtration rate changes on quality,
American Water Works Association, 869-880 1963.
Cleasby, J.L. Approaches to a filterability index for granular filters American Water Works
Association, 372-381, Aug. 1969.
Clifford, D., Ghurye, G., Tripp, A., Tong, J., Field Studies on Arsenic Removal In Albuquerque,
New Mexico Using The University Of Houston/EPA Mobile Drinking Water Treatment Research
Facility Department of Civil and Environmental Engineering, University of Houston, TX, 1998.
72
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Edwards, M., Chemistry of Arsenic Removal During Coagulation and Fe-MN Oxidation Journal
AWWA, 64-78 (1994).
Gibbs, J.W., Scanlan, L.P. "Arsenic Removal In The 1990's: Full Scale Experience From Park City,
Utah", Presentation at the American Water Works Association, Water Quality Technology
Conference, November 1994.
Great Lakes-Upper Mississippi River Board of State Public Health and Environmental Managers,
Recommended Standards for Water Works, (Commonly referred to as the Ten State's Standards,
TSS) Health Education Services, Albany NY, 1992.
Kiminski, J.C. Correspondence in New England Journal, of Medicine 331 (22): 1529-1530 (1994).
O' Melia, C.R., Gray, K.A., and Tao, C. Polymeric Inorganic Coagulants, AWWARF, Denver, CO,
1989.
Pontius, F.W., Brown, K.G., Chen, C.J. Health Implications of Arsenic in Drinking Water Journal
AWWA, 52-63 (1994).
Russo, R. POU/POE Technologies Available For Arsenic Removal Water Technology 72-77 (1998)
U.S. Environmental Protection Agency/NSF International. ETV Protocol of Equipment Verification
Testing For Arsenic Removal, EPA/NSF, January 18, 2000.
U.S. Environmental Protection Agency/NSF International. EPA Test Plan: NSF Equipment
Verification Testing Plan Coagulation and Filtration for Removal of Arsenic, EPA/NSF, January
18, 2000.
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