EPA/600/R-06/159
December 2006
Arsenic Removal from Drinking Water
by Process Modifications to Coagulation/Filtration
U.S. EPA Demonstration Project at Lidgerwood, ND
Final Evaluation Report
by
Wendy E. Condit
Abraham S.C. Chen
Lili Wang
Battelle
Columbus, OH 43201-2693
Contract No. 68-C-00-185
Task Order No. 0019
for
Thomas J. Sorg
Task Order Manager
Water Supply and Water Resources Division
National Risk Management Research Laboratory
Cincinnati, Ohio 45268
National Risk Management Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
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DISCLAIMER
The work reported in this document is funded by the United States Environmental Protection Agency
(EPA) under Task Order 0019 of Contract 68-C-00-185 to Battelle. It has been subjected to the Agency's
peer and administrative reviews and has been approved for publication as an EPA document. Any
opinions expressed in this paper are those of the author(s) and do not, necessarily, reflect the official
positions and policies of the EPA. Any mention of products or trade names does not constitute
recommendation for use by the EPA.
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FOREWORD
The United States Environmental Protection Agency (EPA) is charged by Congress with protecting the
nation's land, air, and water resources. Under a mandate of national environmental laws, the Agency
strives to formulate and implement actions leading to a compatible balance between human activities and
the ability of natural systems to support and nurture life. To meet this mandate, EPA's research program
is providing data and technical support for solving environmental problems today and building a science
knowledge base necessary to manage our ecological resources wisely, understand how pollutants affect
our health, and prevent or reduce environmental risks in the future.
The National Risk Management Research Laboratory (NRMRL) is the Agency's center for investigation
of technological and management approaches for preventing and reducing risks from pollution that
threaten human health and the environment. The focus of the Laboratory's research program is on
methods and their cost-effectiveness for prevention and control of pollution to air, land, water, and
subsurface resources; protection of water quality in public water systems; remediation of contaminated
sites, sediments and groundwater; prevention and control of indoor air pollution; and restoration of
ecosystems. NRMRL collaborates with both public and private sector partners to foster technologies that
reduce the cost of compliance and anticipate emerging problems. NRMRL's research provides solutions
to environmental problems by developing and promoting technologies that protect and improve the
environment; advancing scientific and engineering information to support regulatory and policy
decisions; and providing the technical support and information transfer to ensure implementation of
environmental regulations and strategies at the national, state, and community levels.
This publication has been produced as part of the Laboratory's strategic long-term research plan. It is
published and made available by EPA's Office of Research and Development to assist the user
community and to link researchers with their clients.
Sally Gutierrez, Director
National Risk Management Research Laboratory
in
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ABSTRACT
This report documents the activities performed and the results obtained for the arsenic removal treatment
technology demonstration project at the Lidgerwood, North Dakota, site. The objectives of the project
were to evaluate: (1) the effectiveness of process modifications to an existing coagulation/gravity
filtration plant in removing arsenic to meet the new arsenic maximum contaminant level (MCL) of 10
Hg/L, (2) the reliability of the treatment system, (3) the required system operation and maintenance
(O&M) and operator skills, and (4) the capital and O&M cost of the technology. The project also
characterized water in the distribution system and process residuals produced by the treatment system.
The pre-existing 250 gal/min (gpm) treatment system consisted of pre-chlorination, forced draft aeration,
KMnO4 oxidation, polymer addition, detention, gravity filtration, post-chlorination, and fluoridation.
Chemicals were added into a rapid mix tank ahead of a 15,000-gal baffled detention tank, which provided
about 60 min of detention time. Afterwards, water flowed into four 7.0 ft x 4.3 ft gravity filter cells, each
containing a 24-in deep bed of manganese dioxide (MnO2)-coated anthrasand filter media manufactured
by General Filter Products. The pre-existing treatment plant reduced total arsenic concentrations to an
average level of 31 |o,g/L in the treated water, thus requiring process modifications to achieve arsenic
levels below the new arsenic MCL.
The process modifications included the installation of an iron addition system and a supplemental
polymer addition system. A series of jar and full-scale process tests were conducted to determine a set of
optimum process conditions, which consisted of the addition of 1.2 mg/L (as Fe) of ferric chloride, 0.3
mg/L of Aqua Hawk 9207 PWG polymer (note that 0.1 mg/L of Aqua Hawk 9207 PWG polymer had
already been added to the rapid mix tank prior to the demonstration study), and 0.5 mg/L of Aqua Hawk
127 polymer. These process conditions were implemented on January 1, 2005, and lasted until July 31,
2005, for the demonstration study.
During the seven-month demonstration study period, the system operated for a total of 1,300 hr with an
average daily operating time of 6.1 hr/day. Based on wellhead totalizer readings, the system treated
approximately 22,102,000 gal of water with an average daily water demand of 89,788 gal during this time
period. The treatment system processed approximately 283 gpm of raw water from the wellhead and 26
gpm of reclaim water from the backwash recovery basin. This is equivalent to a hydraulic loading rate of
about 2.6 gpm/ft2 to the filters.
The gravity filters were backwashed automatically every Monday, Wednesday, and Friday. The median
filter run time was 13.3 hr with durations of run time ranging from 8.7 hr to 27.2 hr between two
consecutive backwash cycles. This is equivalent to a median throughput of 225,834 gal of raw water
without reclaim and a range of 147,726 to 461,856 gal of raw water throughput without reclaim. The
longer filter run times up to 27.2 hr were associated with operations over the weekends (between Fridays
and Mondays). Based on headless measurements, it was determined that the rate of differential pressure
(Ap) buildup across the filters was 2.7 in of H2O/hr. Therefore, in order not to exceed 50 in of H2O
headless during the filter runs, the filter run times should be limited to no longer than 15 hr with a
wellhead flowrate of 283 gpm and a reclaim flowrate of 26 gpm.
Total arsenic levels in raw water ranged from 113 to 158 (ig/L with an average value of 129 (ig/L.
Arsenic was present primarily in the As(III) form at an average value of 125 (ig/L. Total iron levels in
source water averaged 1,344 (ig/L and existed primarily in the soluble form. This amount of soluble iron
corresponded to an iron:arsenic ratio of 9:1 given the average soluble iron and soluble arsenic levels in
raw water. Because this was below the target ratio of 20:1 for effective arsenic removal, supplemental
iron addition was required at an average dose of 1.2 mg/L (as Fe) using a ferric chloride solution.
IV
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After detention and prior to the filter, approximately 38% of arsenic was removed through settling within
the baffled detention tank. Based on the average iron dose of 1.2 mg/L and the total iron levels in the raw
water, approximately 37% of the iron participates also were removed within the baffled detention tank.
After the filters, total arsenic levels were reduced to 6.3 to 14.3 |o,g/L and averaged 8.5 |o,g/L. Arsenic in
the treated water was present primarily as As(V) at an average of 5.7 |o,g/L. Particulate arsenic levels
ranged from <0.1 to 4.9 |o,g/L and averaged 1.1 ng/L. Total iron levels in the treated water (existing
solely as particulates) ranged from <25 to 64 |o,g/L.
Due to particulate arsenic breakthrough (up to 14.3 |o,g/L) from the filters, an increase in backwash
frequency would be required to maintain the filter performance to achieve levels consistently below the
10 |og/L MCL. Additional process modifications were implemented based on recommendations
developed from this demonstration study. The modifications included: (1) installing a 40-gpm backwash
reclaim pump to provide additional capacity for daily backwash, (2) implementing a more frequent
backwash schedule, and (3) reducing the wellhead pump flowrate to lower the hydraulic loading rate to
the filters. The 40-gpm reclaim pump was installed at the plant on October 18, 2005. The wellhead
flowrate was reduced to an average value of 239 gpm, which after including the 40 gpm reclaim flowrate,
would yield a hydraulic loading rate of 2.3 gpm/ft2 to the filters. The operator also performed filter
backwash over the weekends in October 2005 and anticipated performing daily backwash as the water
demand increased in the spring and summer.
The existing plant was backwashed automatically on Mondays, Wednesdays, and Fridays. This backwash
schedule was maintained during the demonstration study period due to the limited capacity for backwash
reclaim given the original plant infrastructure. The rate of backwash water production was approximately
5.5% of the amount of treated water produced. The backwash water contained relatively low levels of
soluble arsenic (i.e., 9.8 |o,g/L on average) and soluble iron (i.e., <25 |o,g/L on average). The solids in the
backwash water contained 7.63E+03 to 1.15E+04 (ig/g of arsenic and 1.99E+05 to 3.07E+05 (ig/g of iron.
The backwash solids passed the Toxicity Characteristic Leaching Procedure (TCLP) test with arsenic in
the leachate at <0.5 mg/L. Only barium at 0.069 mg/L and chromium at 0.054 mg/L were detected in the
leachate. The TCLP regulatory limit set by EPA is 5 mg/L for arsenic, 100 mg/L for barium, and 5 mg/L
for chromium. As such, the backwash solids were non-hazardous and could be accumulated and disposed
of at a landfill.
Arsenic levels in water samples collected from the distribution system averaged 12.1 |o,g/L after process
modifications, which was higher than the average arsenic level of 8.5 |o,g/L in the treated water. The
higher levels in the distribution system might be due to longer filter runs over the weekends or
solubilization, destablization, and/or desorption of arsenic-laden particles/scales within the distribution
system. More frequent backwash as implemented in October 2005 would help to eliminate the longer
filter run times over the weekends. Since the process modifications, iron levels in the distribution system
remained at non-detectable levels at <25 |og/L. Manganese levels were generally lower in the distribution
system samples at 6.7 |o,g/L compared to 17.9 |o,g/L in the treated water. Lead and copper levels in the
distribution system were not affected by the process modifications.
The capital investment cost was $57,038 which included $32,452 for equipment, $5,786 for engineering,
and $18,800 for installation. The capital cost was solely for the new equipment required forthe iron
addition system, second polymer mixer, and reclaim pump. This does not include the cost for the second
polymer feed system because an existing spare chemical feed pump and tank were used. The incremental
O&M cost was estimated at $0.04/1,000 gal based on the supplemental iron and polymer dosages
required to achieve the target process conditions. Including the O&M cost for all chemical supplies (i.e.,
chlorine, potassium permanganate, Aqua Hawk 9207 PWG polymer, Aqua Hawk 127 polymer, and
fluoride), electrical usage, and labor, the total O&M cost was estimated at $0.52/1000 gal of treated
water.
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CONTENTS
DISCLAIMER ii
FOREWORD iii
ABSTRACT iv
APPENDICES vii
FIGURES vii
TABLES viii
ABBREVIATIONS AND ACRONYMS ix
ACKNOWLEDGMENTS xi
Section 1.0: INTRODUCTION 1
1.1 Background 1
1.2 Treatment Technologies for Arsenic Removal 1
1.3 Project Objectives 2
Section 2.0: SUMMARY AND CONCLUSIONS 3
Section 3.0: MATERIALS AND METHODS 5
3.1 General Project Approach 5
3.2 System O&M and Cost Data Collection 6
3.3 Sample Collection Procedures and Schedules 7
3.3.1 Source Water Sample Collection 8
3.3.2 Jar Test and Process Test Procedures 8
3.3.3 Macrolite® Pilot Testing 9
3.3.4 Treatment Plant Water Sample Collection 9
3.3.5 Backwash Water Sample Collection 9
3.3.6 Backwash Solid Sample Collection 9
3.3.7 Distribution System Water Sample Collection 9
3.4 Sampling Logistics 10
3.4.1 Preparation of Arsenic Speciation Kits 10
3.4.2 Preparation of Sampling Coolers 10
3.4.3 Sample Shipping and Handling 10
3.5 Analytical Procedures 11
Section 4.0: RESULTS AND DISCUSSION 12
4.1 Facility Description and Pre-Existing Treatment System Infrastructure 12
4.1.1 Source Water Quality 14
4.1.2 Treated Water Quality 14
4.2 Treatment Process Description 16
4.3 Process Modification 20
4.3.1 Treatment Plant Baseline Sampling 21
4.3.2 Jar and Process Testing for Iron Addition 21
4.3.3 Jar and Process Testing for Polymer Addition 27
4.3.4 Macrolite® Pilot Test Results 27
4.3.5 Summary of Process Modifications 30
4.4 System Operation 30
4.4.1 Operational Parameters 30
4.4.1.1 Differential Pressure and Filter Run Tim 31
4.4.1.2 Filter Backwash 34
4.4.2 Residual Management 34
VI
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4.4.3 System/Operation Reliability and Simplicity 35
4.4.3.1 Pre- and Post-Treatment Requirements and Chemical
Handling/Inventory Requirements 35
4.4.3.2 System Automation 35
4.4.3.3 Operator Skill Requirements 36
4.4.3.4 Preventive Maintenance Activities 36
4.5 System Performance after Process Modification 36
4.5.1 Treatment Plant Sampling 36
4.5.1.1 Arsenic Remova 36
4.5.1.2 Iron Removal 39
4.5.1.3 Manganese Removal 39
4.5.1.4 Other Water Quality Parameters 44
4.5.2 Backwash Water Sampling 44
4.5.3 Distribution System Water Sampling 46
4.6 System Cost 49
4.6.1 Capital Cost 49
4.6.2 Operation and Maintenance Cost 50
Section 5.0: REFERENCES 52
APPENDICES
APPENDIX A: OPERATIONAL DATA A-l
APPENDIX B: ANALYTICAL DATA B-l
FIGURES
Figure 4-1. Pre-Existing Water Treatment Facility at Lidgerwood, ND 12
Figure 4-2. Top View of Pre-Existing Gravity Filter Cells (with Two of Four Cells Shown) 13
Figure 4-3. Pre-Existing Backwash Sludge Holding Tank 13
Figure 4-4. Process Schematic of Coagulation/Gravity Filtration Plant at Lidgerwood, ND 16
Figure 4-5. Process Flow Diagram and Sampling Locations 18
Figure 4-6. New Iron Addition System 19
Figure 4-7. Turbidimeters and DataLogger for Process Measurements 20
Figure 4-8. Total and Soluble Arsenic Levels in Filter Cell No. 4 Effluent Under Baseline
Conditions in February 2004 22
Figure 4-9. Turbidity Readings of Filter Cell No. 4 Effluent under Baseline Conditions in
February 2004 22
Figure 4-10. Results of Jar Tests with Addition of FeCl3 or FeSO4 to Raw Water (Tests
Performed by Battelle) 23
Figure 4-11. Jar Test Results with Addition of FeCl3 or FeSO4 to Water Collected from Rapid
Mix Tank (Test Performed by Battelle) 24
Figure 4- 12a. Jar Test Results for FeSO4 to Clearwell Water (Test Performed by EPA) 25
Figure 4-12b. Jar Test Results for Fe2(SO4)3 to Clearwell Water (Test Performed by EPA) 25
Figure 4-13. Total and Soluble Arsenic in Filter Cell No. 4 Effluent with Supplemental Iron
Addition in July 2004 26
Figure 4-14. Total and Soluble Arsenic Concentrations During Macrolite® Pilot Tests 29
Figure 4-15. Headless Across Macrolite® Filter During Pilot Tests 29
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Figure 4-16. Typical Ap Readings Across Filter Cell No. 4 Under Baseline Conditions in
February 2004 32
Figure 4-17. Typical Ap Readings across Filter Cell No. 4 After Process Modifications in
February 2005 32
Figure 4-18. Total Arsenic Concentrations Across Treatment Train 39
Figure 4-19. Concentrations of Arsenic Species Across Treatment Train 40
Figure 4-20. Total Arsenic Concentrations in Treated Water 42
Figure 4-21. Total Iron Concentrations Across Treatment Train 43
Figure 4-22. Total Manganese Concentrations Across Treatment Train 43
Figure 4-23. Turbidity Readings from Filter Cell No. 4 Effluent in February 2004 (Baseline),
July 2004 (Iron Addition), and February 2005 (Supplemental Iron and Polymer
Additions) 45
TABLES
Table 1-1. Summary of Arsenic Removal Demonstration Technologies and Source Water
Quality Parameters 2
Table 3-1. Completion Dates of Pre-Demonstration Study Activities 5
Table 3-2. Evaluation Objectives and Supporting Data Collection Activities 6
Table 3-3. Sample Collection Schedule and Analyses 7
Table 3-4. Summary of Jar Test Parameters 8
Table 4-1. Lidgerwood, ND Raw and Treated Water Quality Results 15
Table 4-2. Lidgerwood, ND Treated Water Quality Data Collected by EPA on April 30, 2003 15
Table 4-3. Design Specifications for Lidgerwood, ND Coagulation/Gravity Filtration Plant 17
Table 4-4. Analytical Results of Baseline Speciation Samples Taken Across Treatment Train
on January 14,2004 21
Table 4-5. Arsenic and Iron Levels in Filter Cell No. 4 Effluent During Iron Addition Process
Testing 26
Table 4-6. Summary of Polymer Jar Test Results Obtained in August 2004 27
Table 4-7. Summary of Macrolite® Pilot Test Analytical Results 28
Table 4-8. Summary of System Operation at the Lidgerwood, ND Site 31
Table 4-9. Summary of AP Buildup Across Filter Cell No. 4 33
Table 4-10. Summary of Backwash Parameters 35
Table 4-11. Summary of Arsenic, Iron, and Manganese Analytical Results 37
Table 4-12. Summary of Other Water Quality Parameter Analytical Results 38
Table 4-13. Summary of Exceedances of 10 |ag/L during Performance Evaluation Study 42
Table 4-14. Backwash Water Sampling Results 47
Table 4-15. Backwash Solid Sample Total Metal Results 47
Table 4-16. Backwash Solids Sample TCLP Results 47
Table 4-17. Distribution Sampling Results 48
Table 4-18. Summary of Capital Cost for the Lidgerwood, ND Process Modifications 49
Table 4-19. O&M Cost for the Lidgerwood, ND Treatment System 51
Vlll
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ABBREVIATIONS AND ACRONYMS
AAL American Analytical Laboratories
Al aluminum
AM adsorptive media
As arsenic
BL baseline sampling
Ca calcium
C/F coagulation/filtration
Cl chlorine
Cu copper
DO dissolved oxygen
EF Extraction Fluid
EPA U.S. Environmental Protection Agency
F fluoride
Fe iron
GFH granular ferric hydroxide
gpd gallons per day
gph gallons per hour
gpm gallons per minute
hp horsepower
ICP-MS inductively coupled plasma-mass spectrometry
ID identification
IX ion exchange
LCR Lead and Copper Rule
MCL maximum contaminant level
MDL method detection limit
MDWCA Mutual Domestic Water Consumer's Association
Mg magnesium
Mn manganese
mV millivolts
Na sodium
NA not available
ND non-detect
NDDH North Dakota Department of Health
NRMRL National Risk Management Research Laboratory
NS not sampled
NTU nephelometric turbidity units
IX
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O&M operation and maintenance
ORD Office of Research and Development
ORP oxidation-reduction potential
P&ID piping and instrumentation diagrams
PM process modifications
QA quality assurance
QAPP quality assurance project plan
QA/QC quality assurance/quality control
RPD relative percent difference
RPM rotations per minute
Sb antimony
SDWA Safe Drinking Water Act
STMGID South Truckee Meadows General Improvement District
STS Severn Trent Services
TCLP Toxicity Characteristic Leaching Procedure
TDS total dissolved solids
TOC total organic carbon
TSS total suspended solids
V vanadium
WRWC White Rock Water Company
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ACKNOWLEDGMENTS
The authors wish to extend their sincere appreciation to the staff of the Water Department in Lidgerwood,
North Dakota. The Lidgerwood, North Dakota, staff monitored the treatment system daily and collected
samples from the treatment system and distribution system on a regular schedule throughout this study.
This performance evaluation would not have been possible without their efforts.
XI
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Section 1.0: INTRODUCTION
1.1 Background
The Safe Drinking Water Act (SDWA) mandates that the United States Environmental Protection Agency
(EPA) identify and regulate drinking water contaminants that may have adverse human health effects and
that are known or anticipated to occur in public water supply systems. In 1975 under the SDWA, EPA
established a maximum contaminant level (MCL) for arsenic at 0.05 mg/L. Amended in 1996, the
SDWA required that EPA develop an arsenic research strategy and publish a proposal to revise the
arsenic MCL by January 2000. On January 18, 2001, EPA finalized the arsenic MCL at 0.01 mg/L (EPA,
2001). In order to clarify the implementation of the original rule, EPA revised the rule text on March 25,
2003, to express the MCL as 0.010 mg/L (10 (ig/L) (EPA, 2003). The final rule requires all community
and non-transient, non-community water systems to comply with the new standard by January 23, 2006.
In October 2001, EPA announced an initiative for additional research and development of cost-effective
technologies to help small community water systems (<10,000 customers) meet the new arsenic standard,
and to provide technical assistance to operators of small systems in order to reduce compliance costs. As
part of this Arsenic Rule Implementation Research Program, EPA's Office of Research and Development
(ORD) proposed a project to conduct a series of full-scale, on-site demonstrations of arsenic removal
technologies, process modifications, and engineering approaches applicable to small systems. Shortly
thereafter, an announcement was published in the Federal Register requesting water utilities interested in
participating in the first round of this EPA-sponsored demonstration program to provide information on
their water systems. In June 2002, EPA selected 17 sites from a list of 115 sites to be the host sites for the
demonstration studies. The water system in Lidgerwood, North Dakota, was selected as one of the Round
1 host sites for the demonstration program.
In September 2002, EPA solicited proposals from engineering firms and vendors for cost-effective arsenic
removal treatment technologies for the 17 host sites. EPA received 70 technical proposals for the 17 host
sites, with each site receiving from one to six proposals. In April 2003, an independent technical panel
reviewed the proposals and provided its recommendations to EPA on the technologies that it determined
were acceptable for the demonstration at each site. Because of funding limitations and other technical
reasons, only 12 of the 17 sites were selected for the demonstration project. Using the information
provided by the review panel, EPA, in cooperation with the host sites and the drinking water programs of
the respective states, selected one technical proposal for each site. Process modifications to the existing
gravity filtration plant with supplemental iron and polymer additions were selected for the Lidgerwood,
North Dakota, facility. The performance evaluation of the system began on January 1, 2005, and was
completed on July 31, 2005.
1.2 Treatment Technologies for Arsenic Removal
The technologies selected for the 12 Round 1 EPA arsenic removal demonstration host sites include nine
adsorptive media systems, one anion exchange system, one coagulation/filtration (C/F) system, and one
C/F process modifications with iron addition. Table 1-1 summarizes the locations, technologies, vendors,
and key source water quality parameters (including arsenic, iron, and pH) of the 12 demonstration sites.
An overview of the technology selection and system design for the 12 demonstration sites and associated
capital cost is provided in two EPA reports (Chen et al., 2004; Wang et al., 2004), which are posted on the
EPA Web site at http://www.epa.gov/ORD/NRMRL/arsenic/ resource.htm.
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1.3
Project Objectives
The objective of the Round 1 arsenic demonstration program is to conduct 12 full-scale arsenic treatment
technology demonstration studies on the removal of arsenic from drinking water supplies. The specific
objectives are to:
• Evaluate the performance of the arsenic removal technologies for use on small
systems
• Determine the required system operation and maintenance (O&M) and operator
skill levels
• Determine the capital and O&M cost of the technologies
• Characterize process residuals produced by the technologies.
This report summarizes the performance of the process modifications at the gravity filtration plant at
Lidgerwood, North Dakota, from January 1, 2005, through July 31, 2005. The types of data collected
include system operation, water quality (both across the treatment train and in the distribution system),
residuals, and capital and O&M cost.
Table 1-1. Summary of Arsenic Removal Demonstration
Technologies and Source Water Quality Parameters
Demonstration Site
WRWC Public Water
System, NH
Rollinsford, NH
Queen Anne's County, MD
Brown City, MI
Climax, MN
Lidgerwood, ND
Desert Sands MDWCA, NM
Nambe Pueblo, NM
Rimrock, AZ
Valley Vista, AZ
Fruitland, ID
STMGID, NV
Technology
(Media)
AM(G2)
AM(E33)
AM (E33)
AM (E33)
C/F
PM
AM (E33)
AM (E33)
AM (E33)
AM (AAFS50)
IX
AM (GFH)
Vendor
ADI
AdEdge
STS
STS
Kinetico
Kinetico
STS
AdEdge
AdEdge
Kinetico
Kinetico
USFilter
Design
Flowrate
(gpm)
70(a)
100
300
640
140
250
320
145
90(a)
37
250
350
Source Water Quality
As
(Hg/L)
39
36(b)
19(b)
14(b)
39(b)
146(b)
23(b)
33
50
41
44
39
Fe
(Hg/L)
<25
46
270(c)
127oo
546(c)
l,325(c)
39
<25
170
<25
<25
<25
PH
7.7
8.2
7.3
7.3
7.4
7.2
7.7
8.5
7.2
7.8
7.4
7.4
AM = adsorptive media process; C/F = coagulation/filtration; GFH = granular ferric hydroxide; IX = ion
exchange; PM = process modifications; MDWCA = Mutual Domestic Water Consumer's Association; STMGID
= South Truckee Meadows General Improvement District; STS = Severn Trent Services; WRWC = White Rock
Water Company
(a) System reconfigured from parallel to series operation due to a reduced flowrate of 40 gal/min (gpm).
(b) Arsenic existing mostly as As(III).
(c) Iron existing mostly as soluble Fe(II).
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Section 2.0: SUMMARY AND CONCLUSIONS
The following conclusions were made relating to the overall objectives of the treatment technology
demonstration study:
Performance of the arsenic removal technology for use on small systems:
• With supplemental iron and polymer additions (i.e., 1.2 mg/L [as Fe] of ferric chloride,
0.3 mg/L of Aqua Hawk 9207 PWG polymer, and 0.5 mg/L of Aqua Hawk 127
polymer), the MnO2-coated anthrasand gravity filtration system was able to remove
arsenic to <10 (ig/L.
• Chlorine and potassium permanganate (KMnO4) were effective in oxidizing As(III) to
As(V), reducing As(III) concentrations from 125 (ig/L (on average) in raw water to 1.8
(ig/L (on average) after the rapid mix and detention tanks. It was also noted that
approximately 38% of total arsenic was removed through settling in the detention tank.
• Because occasional particulate arsenic breakthrough was observed in the filter effluent,
several operational changes were made including more frequent filter backwash (such as
daily), higher reclaim rates (from 9.2% to 16.7%), and lower hydraulic loading rates
(from 2.6 to 2.3 gpm/ft2), were implemented after the demonstration study period.
• Retrofitting the filters with Macrolite® filter media was not recommended because of the
potential for higher rates of pressure buildup and shorter run times than observed in the
full-scale plant.
Required system O&M and operator skill levels:
• There was no unscheduled downtime during the demonstration study period from
January 1, 2005, to July 31, 2005. However, operational issues were experienced
related to headless buildup on the filter cells and the need for more frequent
backwash. Therefore, several operational changes were implemented in October
2005.
• The weekly demand for operator labor was approximately 11 hr and the O&M of
the system required a significant level of mechanical and electrical skills to
ensure proper operation of pumps, controls, and other system components. The
operator also required a strong working understanding of chemical feed system
O&M for the six chemicals used in pre- and post-treatment.
Process residuals produced by the technology:
• The rate of backwash water generation was 5.5% of the amount of treated water
produced. The backwash solids generated showed no detectable arsenic
concentrations in the leachate from the Toxicity Characteristic Leaching
Procedure (TCLP) and, therefore, were suitable for landfill disposal. Due to the
increased solids loading from the iron addition, the frequency of sludge removal
from the detention tank increased from annually to biannually.
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Cost-effectiveness of the technology:
The capital investment cost was $57,038 which included $32,452 for equipment, $5,786
for engineering, and $18,800 for installation.
The incremental O&M cost was $0.04/1,000 gal based on supplemental iron and polymer
dosages required to achieve the target process conditions. The total O&M cost was
estimated to be $0.52/1000 gal for all chemical supplies (i.e., chlorine, potassium
permanganate, ferric chloride, Aqua Hawk 9207 PWG polymer, Aqua Hawk 127
polymer, and fluoride), electrical consumption, and labor.
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Section 3.0: MATERIALS AND METHODS
3.1
General Project Approach
Prior to the commencement of the performance evaluation study, a number of pre-demonstration activities
were performed as summarized in Table 3-1. Among the activities performed were a series of jar and
process tests that were carried out to establish a process modification approach that evolved to comprise
supplemental iron and polymer additions to the coagulation/gravity filtration system. The performance
evaluation of the process modifications began on January 1, 2005, and ended on July 31, 2005. Table 3-2
summarizes the types of data collected and/or considered as part of the technology evaluation process.
The overall performance of the process modifications was evaluated based on its ability to consistently
remove arsenic to the target MCL of 10 |o,g/L through the collection of weekly and monthly water samples
across the treatment train. The reliability of the process modifications was evaluated by tracking the
unscheduled system downtime and frequency and extent of equipment repair and replacement. The
unscheduled downtime and repair information were recorded by the plant operator on a Repair and
Maintenance Log Sheet.
Table 3-1. Completion Dates of Pre-Demonstration Study Activities
Activity
Introductory Meeting Held
Request for Quotation Issued to Vendor
Vendor Quotation Received by Battelle
Purchase Order Completed and Signed
Letter of Understanding Issued
Letter Report Issued
Engineering Package Submitted to NDDH
Installation Approved by NDDH
Iron Addition System Installed
Iron Addition Jar Tests Completed
Baseline Process Testing Completed
Iron Addition Process Testing Completed
Polymer Addition Jar Tests Completed
Date
07/31/03
08/01/03
09/29/03
10/16/03
08/22/03
10/20/03
11/17/03
12/08/03
01/14/04
01/15/04
03/09/04
07/31/04
08/13/04
NDDH = North Dakota Department of Health
The required system O&M and operator skill levels were evaluated based on a combination of
quantitative data and qualitative considerations, including the need for pre- and/or post-treatment, level of
system automation, extent of preventive maintenance activities, frequency of chemical and/or media
handling and inventory, and general knowledge needed for relevant chemical processes and related health
and safety practices. The staffing requirements for the system operation were recorded on an Operator
Labor Hour Log Sheet.
The cost of the system was evaluated based on the capital cost per gal/min (gpm) (or gal/day [gpd]) of
design capacity and the O&M cost per 1,000 gal of water treated. This task required the tracking of
capital cost for equipment, engineering, and installation, as well as the O&M cost for chemical supply,
electrical power use, and labor.
-------
Table 3-2. Evaluation Objectives and Supporting Data Collection Activities
Evaluation Objectives
Performance
Reliability
System O&M and
Operator Skill
Requirements
Cost-Effectiveness
Residual Management
Data Collection
-Ability to consistently meet 10 ^g/L of arsenic in treated water
-Unscheduled system downtime
-Frequency and extent of repairs including a description of problems,
materials and supplies needed and associated labor and cost
-Pre- and post-treatment requirements
-Level of automation for system operation and data collection
-Staffing requirements including number of operators and laborers
-Task analysis of preventive maintenance including number, frequency, and
complexity of tasks
-Chemical handling and inventory requirements
-General knowledge needed of relevant chemical processes and health and
safety practices
-Capital cost for equipment, engineering, and installation
-O&M cost for chemical usage, electricity consumption, and labor
-Quantity of residuals generated by process
-Characteristics of aqueous and solid residuals
The quantity of aqueous and solid residuals generated was estimated by tracking the amount of backwash
water produced during each backwash cycle. Backwash water was sampled and analyzed for chemical
characteristics.
3.2
System O&M and Cost Data Collection
The plant operator performed daily, weekly, and monthly system O&M and data collection according to
instructions provided by the vendor and Battelle. On a daily basis, the plant operator recorded system
operational data, such as pressure, flowrate, totalizer, and hour meter readings on a Daily System
Operation Log Sheet; the operator also checked levels of various chemicals and conducted visual
inspections to ensure normal system operations. In the event of problems, the plant operator would
contact the Battelle Study Lead, who then would determine if the vendor should be contacted for
troubleshooting. The plant operator recorded all relevant information, including the problem
encountered, course of action taken, materials and supplies used, and associated cost and labor on the
Repair and Maintenance Log Sheet. On a weekly basis, the plant operator measured pH, temperature,
dissolved oxygen (DO), and oxidation-reduction potential (ORP), and recorded the data on a Weekly On-
site Water Quality Parameters Log Sheet.
The capital cost for the process modifications included the cost for equipment, site engineering, and
system installation. The incremental O&M cost consisted primarily of expenses for additional chemicals.
Consumption of ferric chloride and polymer was tracked on the Daily System Operation Log Sheet.
Labor for various activities, such as the routine system O&M, troubleshooting and repair, and demonstra-
tion-related work, was traced using an Operator Labor Hour Log Sheet. The routine O&M included
activities such as completing field logs, replenishing chemical solutions, ordering supplies, performing
system inspections, and others as recommended by the vendor. The labor for demonstration-related work,
including activities such as performing field measurements, collecting and shipping samples, and
communicating with the Battelle Study Lead and the vendor, was recorded, but not used for cost analysis.
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3.3
Sample Collection Procedures and Schedules
To evaluate the effectiveness of the process modifications, samples were collected at the wellhead, across
the treatment plant, during filter backwash, and from the distribution system. Table 3-3 provides the
sampling schedules and analyztes measured during each sampling event (Battelle, 2004). Specific
requirements for analytical methods, sample volumes, containers, preservation, and holding times are
presented in Table 4-1 of the EPA-endorsed Quality Assurance Project Plan (QAPP) (Battelle, 2003).
The procedure for arsenic speciaiton is described in Appendix A of the QAPP.
Table 3-3. Sample Collection Schedule and Analyses
Sample
Type
Source Water
Treatment
Plant Water
Distribution
Water
Backwash
Water
Residual
Sludge
Sample
Locations'3'
At Wellhead (IN)
At Wellhead (IN),
Before Filter (BF),
After Filter (AF),
Post-Chlorination (PC)0
At Wellhead (IN),
Before Filter (BF),
After Filter (AF)
Post-Chlorination (PC)0
Three LCR Residences
At Backwash Discharge
Line from Two Filters
From Backwash Water
Reclaim Tank
No. of
Samples
1
4
3
3
2
2
Frequency
Once (during
initial site
visit)
Weekly
Monthly
Monthly
Monthly
Once
Analytes
As(total), particulate As,
As(III), As(V), Fe (total and
soluble), Mn (total and soluble),
Al (total and soluble), Na, Ca,
Mg, V, Mo, Sb, Cl, F, SO4,
SiO2, PO4, TOC, turbidity, and
alkalinity
On-site: pH, temperature,
DO/ORP, and C12 (free and
total) (at PC location)
Off-site: As (total), Fe (total),
Mn (total), SiO2, PO4, turbidity,
and alkalinity
On-site: pH, temperature,
DO/ORP, and C12 (free and
total) (at PC location).
Off-site: As( total and soluble)
particulate As, As(III), As(V),
Fe (total and soluble), Mn (total
and soluble), Ca, Mg, F, NO3>
SO4, SiO2, PO4, turbidity, and
alkalinity
pH, alkalinity, As (total), Fe
(total), Mn (total), Pb (total),
and Cu (total)
TDS, turbidity, pH, As
(soluble), Fe (soluble), and Mn
(soluble)
TCLP Metals
As(Total)
Date(s) Samples
Collected
07/31/03
01/11/05,01/18/05,
01/25/05, 02/08/05
02/15/05,02/22/05
03/08/05,03/15/05,
03/22/05, 03/29/05,
04/12/05,04/18/05
04/26/05,05/11/05,
05/17/05, 05/24/05,
05/31/05,06/07/05,
06/21/05, 06/28/05,
07/06/05,07/19/05,
07/25/05
01/04/05, 02/01/05
03/01/05, 04/05/05
05/03/05, 06/14/05
07/12/05
Baseline Sampling(b)
12/02/03, 12/17/03
01/06/04, 01/22/04
Monthly Sampling:
01/18/05,02/22/05
03/22/05, 04/06/05
05/03/05, 06/14/05
07/12/05
03/23/05,04/18/05
05/25/05, 06/21/05
07/25/05
11/02/05
(a) Abbreviation corresponding to sample location in Figure 4-6.
(b) Four baseline sampling events performed before system became operational.
(c) PC location analysis only for pH, temperature, C12 (free and total), turbidity, and ICP-MS total and soluble metals. No
monthly arsenic speciation samples.
LCR = Lead and Copper Rule
-------
3.3.1 Source Water Sample Collection. During the initial visit to the site, one set of source water
samples was collected and speciated using an arsenic speciation kit (see Section 3.4.1). The source water
also was measured for pH, temperature, DO, and ORP on site. The sample tap was flushed for several
minutes before sampling; special care was taken to avoid agitation, which might cause unwanted
oxidation. Analytes for the source water samples are listed in Table 3-3.
3.3.2 Jar Test and Process Test Procedures. Prior to the start of the performance evaluation
study, a series of jar and process tests were conducted to determine the process conditions needed to
achieve below 10 |o,g/L of arsenic in the treated water. To determine the supplemental iron dosage, four
jar tests were conducted, each consisting of an iron salt (i.e., ferric chloride [FeCl3] or ferrous sulfate
[FeSO4]) and a water sample taken either at the wellhead or after the rapid mix tank. The water taken
from the rapid mix tank had already been dosed with sodium hypochlorite (NaOCl), potassium
permanganate (KMnO4), and a non-ionic polymer, Aqua Hawk 9207 PWG. Each test consisted of dosing
an iron salt with increasing dosages into a series of six 1-L jars placed on a Phipps & Byrd overhead
stirrer/jar tester with an illuminated base. Table 3-4 summarizes the experimental conditions for these jar
tests. For Tests 1 and 2, NaOCl was added at a dosage of approximately 2.3 mg/L to oxidize As(III) and
Fe(II) in raw water (and Fe[II] added as supplemental iron in Test 2). For Test 4, NaOCl also was added
up to 0.3 mg/L to oxidize Fe(II) added as supplemental iron. pH values were monitored at the beginning
and end of each jar test, but not adjusted during the test. After the specified contact time, the supernatant
in each jar was filtered with 0.45-|o,m disc filters and analyzed for arsenic, iron, and manganese. The
results of the jar tests are summarized in Section 4.3.2.
Table 3-4. Summary of Jar Test Parameters
Parameter
Jarl
Jar 2
Jar 3
Jar 4
Jar 5
Jar 6
Jar Tests with Raw Water
Mix Time (min)
Test 1 : Ferric Chloride, mg/L (as Fe)
Test 2: Ferrous Sulfate, mg/L (as Fe)
30
0
0
30
0.18
0.20
30
0.36
0.41
30
0.54
0.61
30
0.72
0.81
30
0.91
1.02
Jar Tests with Rapid Mix Tank Water
Mix Time (min)
Test 3 : Ferric Chloride, mg/L (as Fe)
Test 4: Ferrous Sulfate, mg/L (as Fe)
60
0
0
60
0.09
0.10
60
0.18
0.20
60
0.27
0.30
60
0.36
0.41
60
0.45
0.51
EPA subsequently conducted four jar tests using water collected from the clearwell. These jar tests
consisted of varying dosages of ferrous sulfate (FeSO4) and ferric sulfate (Fe2[SO4]3). The ferrous iron
dosages ranged from 0.2 to 1.2 mg/L (as Fe) and the ferric iron dosages ranged from 0.2 to 1.2 mg/L (as
Fe). The jars were mixed for 30 min at 20 rotations per minute (RPM). The supernatant was filtered with
both 0.45 and 0.20 jam disc filters and analyzed for arsenic, iron, and manganese. The results of the jar
tests are summarized in Section 4.3.2.
After the jar tests were completed, full-scale process tests began with supplemental iron addition to the
treatment plant. During this timeframe, effluent from Filter Cell No. 4 was monitored on-line on a daily
basis for turbidity and total and soluble arsenic, iron, and manganese to further assess the process
conditions. The results of the process testing are summarized in Section 4.3.2.
Subsequent to the supplemental iron addition process testing, eight jar tests were conducted to select a
supplemental polymer using the Phipps & Byrd jar test apparatus described above. Five polymers, i.e.,
-------
Aqua Hawk 927, Aqua Hawk 9207 PWG, Aqua Hawk 2757, Aqua Hawk 6427, and Aqua Hawk 127,
were tested at concentrations ranging from 0.2 to 10 mg/L. The polymers were dosed into 1-L jars and
mixed with the Phipps & Byrd overhead stirrer/jar tester. The supernatant was filtered with 0.45 jam disc
filters to simulate the performance of the gravity filter media and with 0.22 jam disc filters to analyze for
soluble metals in the gravity filter effluent. The results of these jar tests are presented in Section 4.3.3.
On September 21, 2004, the operator set up an additional polymer feed system to test full-scale plant
operations with the addition of the second polymer selected from the jar tests.
3.3.3 Macrolite* Pilot Testing. A pilot test was performed by the selected equipment vendor,
Kinetico, from March 28 to April 11, 2005, to determine if a potential retrofit of the existing gravity filter
cells with Macrolite® media would result in improved arsenic removal. Macrolite® is a low-density,
spherical, and chemically inert ceramic media. It is designed for high-rate filtration up to 10 gpm/ft2 and
typically used in treatment systems configured with pressurized filter tanks. However, Kinetico has used
Macrolite® media in gravity filter plants for surface water treatment. The pilot test was conducted on-site
using Kinetico's 1-ft2 pilot plant apparatus loaded with 24-in of Macrolite® media. The flowrate to the
pilot plant apparatus was approximately 2.0 gpm, resulting in a 2.0 gpm/ft2 hydraulic loading rate similar
to that (i.e., 2.1 gpm/ft2) of the full-scale gravity filters.
Two different pilot tests were conducted. The first pilot test from April 1 to 3, 2005, consisted of three
individual runs (with Well No. 3 running during the test). Water for the first pilot test was taken from the
top of the filters with the same chemical dosages used on the full-scale plant (e.g. NaOCl, KMnO4, FeCl3,
Aqua Hawk 9207 PWG, and Aqua Hawk 127). The second pilot test from April 8 to 10, 2005, also
consisted of three individual runs and used raw water from Well No. 1 with the addition of only KMnO4
to oxidize iron and arsenic. The test was conducted in order to determine if improved arsenic removal
could be achieved by a Macrolite® filter without the use of supplemental polymers, i.e., Aqua Hawk 9207
PWG, and Aqua Hawk 127, required for the full-scale plant. The pilot unit was backwashed at the end of
the day after each individual run.
3.3.4 Treatment Plant Water Sample Collection. During the system performance evaluation
study, the plant operator collected weekly samples across the treatment train, on a four-week cycle, for
on- and off-site analyses. For the first three weekly events, samples were collected at four locations (i.e.,
at the wellhead [IN], before filter [BF], after filter [AF], and post-chlorination from clearwell [PC]) and
analyzed for the analytes listed under the weekly treatment plant analyte list in Table 3-3. For the fourth
weekly event, samples taken at four locations (i.e., IN, BF, AF, PC) were speciated on-site and analyzed
for the analytes listed under the monthly treatment plant analyte list in Table 3-3.
3.3.5 Backwash Water Sample Collection. Backwash water samples were collected monthly
from two of the four gravity filters. Unfiltered samples were measured on-site for pH and off-site for
total dissolved solids (TDS) and turbidity. Filtered samples using 0.45-(im disc filters were analyzed for
soluble As, Fe, and Mn.
3.3.6 Backwash Solid Sample Collection. Backwash solid samples were collected from 1-gal
plastic jars containing backwash water/solid mixtures collected during a backwash event on October 6,
2005. After solids in the jar were settled and the supernatant was carefully decanted, one aliquot of the
solids/water mixture was taken for TCLP testing. The remaining solid/water mixture was air-dried, acid-
digested, and analyzed for Mg, Al, Si, P, Ca, Fe, Mn, Ni, Cu, Zn, As, Cd, and Pb.
3.3.7 Distribution System Water Sample Collection. Samples were collected from the
distribution system by the plant operator to determine the impact of the process modifications on the
water chemistry in the distribution system - specifically, lead and copper levels. From December 2003 to
January 2004, prior to the startup of the process modifications, four bi-monthly baseline distribution
-------
system sampling events were conducted at three locations within the distribution system. Following the
start-up of the process modifications, distribution system sampling continued on a monthly basis at the
same three locations.
The three homes selected for sampling had been included in the City's Lead and Copper Rule (LCR)
sampling. The samples collected at the LCR locations were taken following an instruction sheet
developed according to the Lead and Copper Monitoring and Reporting Guidance for Public Water
Systems (EPA, 2002). The first draw sample was collected from a cold-water faucet that had not been
used for at least 6 hr to ensure that stagnant water was sampled. The sampler recorded the date and time
of last water use before sampling and the date and time of sample collection for calculation of the
stagnation time. Analytes for the baseline samples coincided with the monthly distribution system water
samples as described in Table 3-3. Arsenic speciation was not performed for the distribution system
water samples.
3.4 Sampling Logistics
All sampling logistics, including arsenic speciation kits preparation, sample cooler preparation, and
sample shipping and handling, are discussed below.
3.4.1 Preparation of Arsenic Speciation Kits. The arsenic field speciation method used an anion
exchange resin column to separate the soluble arsenic species, As(V) and As(III) (Edwards et al., 1998).
Resin columns were prepared in batches at Battelle laboratories according to the procedures detailed in
Appendix A of the EPA-endorsed QAPP (Battelle, 2003).
3.4.2 Preparation of Sampling Coolers. For each sampling event, a sample cooler was prepared
with the appropriate number and type of sample bottles, disc filters, and/or speciation kits. All sample
bottles were new and contained appropriate preservatives. Each sample bottle was affixed with a pre-
printed, colored-coded, and waterproof label, consisting of the sample identification (ID), date and time of
sample collection, collector's name, site location, sample destination, analysis required, and preservative.
The sample ID consisted of a two-letter code for the specific water facility, sampling date, a two-letter
code for a specific sampling location, and a one-letter code designating the arsenic speciation bottle (if
necessary). The sampling locations at the treatment plant were color-coded for easy identification. The
pre-labeled bottles for each sampling location were placed separate in ziplock bags and packed in the
cooler.
When appropriate, the sample cooler was packed with bottles for the three distribution system sampling
locations and/or the two backwash sampling locations (one for each vessel). In addition, a packet
containing all sampling and shipping-related supplies, such as latex gloves, sampling instructions, chain-
of-custody forms, UPS air bills, ice packs, and bubble wrap, was placed in the cooler. Except for the
operator's signature, the chain-of-custody forms and UPS air bills had already been completed with
the required information. The sample coolers were shipped via FedEx to the facility approximately one
week prior to the scheduled sampling date.
3.4.3 Sample Shipping and Handling. After sample collection, samples for off-site analyses were
packed carefully in the original coolers with wet ice and shipped to Battelle. Upon receipt, sample
custodians verified that all samples indicated on the chain-of-custody forms were included and intact.
Sample IDs were checked against the chain-of-custody forms and the samples were logged into the
laboratory sample receipt log. Discrepancies noted by the sample custodian were addressed with the plant
operator by the Battelle Study Lead.
10
-------
Samples for water quality analyses were packed in separate coolers and picked up by couriers from
American Analytical Laboratories (AAL) in Columbus, Ohio, and TCCI Laboratories in New Lexington,
Ohio, both of which were under contract with Battelle for this demonstration study Samples for metal
analyses were stored at Battelle's Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) Laboratory.
The chain-of-custody forms remained with the samples from the time of preparation through analysis and
final disposition. All samples were archived by the appropriate laboratories for the respective duration of
the required hold time and disposed of properly thereafter.
3.5 Analytical Procedures
Field measurements of pH, temperature, DO, and ORP were conducted by the plant operator using a
WTW Multi 340i handheld meter, which was calibrated for pH and DO prior to use following the
procedures provided in the user's manual. The ORP probe also was checked for accuracy by measuring
the ORP of a standard solution and comparing it to the expected value. The plant operator collected a
water sample in a clean 400-mL plastic beaker and placed the Multi 340i probe in the beaker until a stable
value was obtained. The plant operator also performed free and total chlorine measurements using
Hach™ chlorine test kits following the user's manual.
The analytical procedures described in Section 4.0 of the EPA-endorsed QAPP (Battelle, 2003) were
followed by Battelle's ICP-MS Laboratory, AAL, and TCCI Laboratories. Laboratory quality
assurance/quality control (QA/QC) of all methods followed the prescribed guidelines. Data quality in terms
of precision, accuracy, method detection limit (MDL), and completeness met the criteria established in the
QAPP, i.e., relative percent difference (RPD) of 20%, percent recovery of 80% to 120%, and completeness
of 80%. The quality assurance (QA) data associated with each analyte will be presented and evaluated in a
quality assurance/quality control (QA/QC) Summary Report to be prepared under separate cover upon
completion of the Arsenic Demonstration Project.
11
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4.1
Section 4.0: RESULTS AND DISCUSSION
Facility Description and Pre-Existing Treatment System Infrastructure
The water treatment system at Lidgerwood, North Dakota, supplies drinking water to approximately 750
community members. Located on Highway 18 North, the system has a design capacity of 250 gpm to
meet the peak daily demand of 180,000 gpd. Source water is pumped from two 98-ft deep wells (one
each north and south side) alternating on a monthly basis. The pre-existing treatment system housed in
the building shown in Figure 4-1 consists of pre-chlorination, forced draft aeration, KMnO4 oxidation,
polymer coagulant addition, detention, gravity filtration, post-chlorination, and fluoridation. There are
four gravity filter cells filled with MnO2-coated anthrasand. Figure 4-2 shows the top of two of the four
gravity filter cells. The system also is equipped with a backwash reclaim system consisting of an 18,000-
gal backwash water reclaim basin and a !/2-horsepower (hp) reclaim pump. The sludge removed from the
reclaim basin gets stored in a 20-ft diameter by 9-ft and 5-in tall sludge holding tank and excess water
filtered off of the sludge is returned for treatment (Figure 4-3). The treated water is stored in a 30,000-gal
clearwell before being pumped to the 50,000-gal water tower located in town. A detailed description of
the pre-existing treatment plant and subsequent process modifications is provided in Section 4.2.
Figure 4-1. Pre-Existing Water Treatment Facility at Lidgerwood, ND
12
-------
Figure 4-2. Top View of Pre-Existing Gravity Filter Cells (with Two of Four Cells Shown)
Figure 4-3. Pre-Existing Backwash Sludge Holding Tank
13
-------
4.1.1 Source Water Quality. Source water samples were collected on July 31, 2003, and
subsequently analyzed for the analytes listed in Table 3-3. Table 4-1 presents the results of the source
water analyses, along with those provided by the facility to EPA for the demonstration site selection and
those independently collected and analyzed by EPA, North Dakota Department of Health (NDDH), and
the vendor.
As shown in Table 4-1, total arsenic concentrations in source water ranged from 108 to 146.2 ug/L.
Based on Battelle's July 31, 2003, sampling results, 82% of total arsenic existed as As (III) at 120.6 ug/L,
and 14% as particulate As at 20.3 ug/L. Iron concentrations in source water ranged from 1,310 to 1,620
ug/L existing almost completely as soluble iron. A general rule is that the soluble iron concentration
should be at least 20 times the soluble arsenic concentration for effective removal of arsenic onto iron
solids (Sorg, 2002). The results from the July 31, 2003, sampling event indicated that the soluble iron
level was approximately 10 times the soluble arsenic level. Because the natural iron content in source
water was below the target 20:1 Fe:As ratio, the system would require supplemental iron addition to
achieve below 10 ug/L treatment results. The manganese levels were elevated, ranging from 111 to 675
ug/L and existed mainly as soluble manganese. The pH values ranged from 7.2 to 7.5. Hardness ranged
from 435 to 520 mg/L, silica from 27.8 to 32.1 mg/L, and sulfate from 341 to 390 mg/L. Although, silica
and sulfate can compete with arsenic for removal onto iron solids, these concentrations were not high
enough to show significant impact on arsenic removal.
4.1.2 Treated Water Quality. Tables 4-1 and 4-2 summarize the results of treated water samples
collected by Battelle, EPA, and NDDH. In general, treated water samples had lower arsenic, iron, and
manganese concentrations than source water samples, while other parameters remained within the range
of source water concentrations. Table 4-1 shows that arsenic concentrations in the treated water ranged
from 25.7 to 31.1 ug/L from 1998 through 2003. Iron concentrations ranged from below the method
detection limit of ug/L to 109 ug/L (which is below the secondary MCL of 300 ug/L for iron, but
suggests particulate breakthrough from the gravity filters). Manganese concentrations ranged from <10 to
101 ug/L (the secondary MCL for manganese is 50 ug/L).
Table 4-2 presents the analytical results of the water samples collected across the treatment train by EPA
in April 2003. These samples were collected at the wellhead, after aeration/oxidation, before the filters,
after the filters, and after the post-chlorination point. Total arsenic and iron concentrations in source
water were 129 ug/L and 1,390 ug/L, respectively. After prechlorination and aeration, approximately
20% of total arsenic, or 19 ug/L, was present in the soluble form with the remainder existing as
particulate. Iron was present entirely in particulate form after aeration with total iron concentration at
924 ug/L. After the detention tank and before the filters, total arsenic and total iron levels decreased by
approximately 32% and 38%, respectively, indicating that significant settling of particles had been taking
place within the detention tank. After the filters, the total arsenic level was 18 ug/L, which was present
only in the soluble form and somewhat lower than historic levels (i.e., 25.7 to 31.1 ug/L) obtained by
NDDH. There was no particulate arsenic observed in the water sample collected after the filters. Based
on these treated water sampling results, it was determined that supplemental iron would be needed for
further removal of soluble arsenic to reach the arsenic MCL of 10 ug/L.
14
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Table 4-1. Lidgerwood, ND Raw and Treated Water Quality Results
Parameter
Date
PH
Alkalinity (as CaCO3)
Hardness (as CaCO3)
Chloride
Fluoride
Sulfide
Sulfate
Silica (as SiO2)
Orthophosphate (as PO4)
TOC
As (total)
As (soluble)
As (paniculate)
As (III)
As(V)
Fe (total)
Fe (soluble)
Al (total)
Al (soluble)
Mn (total)
Mn (soluble)
V (total)
V (soluble)
Mo (total)
Mo (soluble)
Sb (total)
Sb (soluble)
Na (total)
Ca (total)
Mg (total)
Unit
-
S.U.
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
HB/L
HR/L
^g/L
^g/L
^g/L
^g/L
^g/L
HB/L
HB/L
HB/L
HB/L
HB/L
HB/L
^g/L
^g/L
^g/L
^g/L
mg/L
mg/L
mg/L
Raw Water
Utility
Data
NA
7.5
385
444
36
NS
NS
344
27.8
0.065
NS
108
NS
NS
NS
NS
1,310
NS
NS
NS
544
NS
NS
NS
NS
NS
NS
NS
142
128
29
EPA
Data
09/03/02
NS
NS
435
NS
NS
114
341
28.5
NS
NS
129
NS
NS
NS
NS
1,390
NS
<25
NS
111
NS
NS
NS
NS
NS
<25
NS
147
125
30
Vendor
Data
NA
7.3
368
520
81
0.5
NS
350
32.1
0.1
NS
128
NS
NS
NS
NS
1,620
NS
NS
NS
660
NS
NS
NS
NS
NS
NS
NS
148
147
38
Battelle
Raw
Water
Data
07/31/03
7.2
344
513
82
0.8
NS
390
29.4
0.10
<1.0
146.2
125.9
20.3
120.6
5.3
1,325
1,316
<10
<10
675
665
O.I
O.I
2.7
2.5
0.1
0.1
131
148
35
Treated Water
Battelle
Treated
Water
Data
07/31/03
NS
NS
510
NS
NS
NS
NS
NS
NS
NS
30.5
17.6
12.8
0.1
17.6
69
54
<10
<10
101
14.8
O.I
O.I
5.1
5.3
0.1
0.1
130
147
35
NDDH
Treated
Water
Data
1998 to 2003
6.9-7.4
364 - 403
477-481
58-66
1.3
NS
373-384
NS
NS
NS
25.7-31.1
NS
NS
NS
NS
<10 - 109
NS
<50
NS
<10-46
NS
NS
NS
NS
NS
0.1
NS
160 - 168
136-138
33
NA = not available; ND = non-detect; NS = not sampled
Table 4-2. Lidgerwood, ND Treated Water Quality Data Collected by EPA on April 30, 2003
Sample Location
At Wellhead
After Aeration
Before Filters
After Filters
After Post-Chlorination
As (total)
(Hg/L)
129
97
88
18
21
As (soluble)
(Hg/L)
NS
19
15
22
18
Fe (total)
(Hg/L)
1,390
924
863
<25
<25
Fe (soluble)
(HS/L)
NS
<25
<25
<25
<25
NS = not sampled
15
-------
4.2
Treatment Process Description
Figure 4-4 is a process schematic of the treatment train for the Lidgerwood, North Dakota, plant. The
pre-existing treatment system consisted of pre-chlorination, forced draft aeration, KMnO4 oxidation,
polymer coagulant addition, detention, gravity filtration, post-chlorination, and fluoridation. Table 4-3
summarizes the major components and design parameters. The process modifications included the use of
supplemental iron and polymer additions to enhance arsenic removal by the filters. Figure 4-5 presents a
process flowchart, along with the sampling/analysis schedule, for the process modifications. The major
process steps and system components are presented as follows:
• Pre-Chlorination. A gas chlorine feed system was used to maintain chlorine residuals
and prevent biological growth across the treatment train and oxidize As(III), Fe(II), and
Mn(II) in raw water prior to aeration. The pre-chlorination dosage was targeted at 1.8
mg/L (as C12).
• Aeration. Forced-draft aeration with a 1-hp blower was used to promote the transfer of
oxygen from air to water to further oxidize iron and manganese within the tray aeration
unit.
• Rapid Mixing with KMnO4 Oxidation and Iron and Polymer Additions. A rapid
mix tank was used prior to the detention tank to provide for KMnO4, FeCl3, and polymer
addition into the aerated water. A supplementary oxidation step was provided by the
addition of KMnCk, which was stored in a 50-gal tank and added at a dosage of
approximately 0.7 mg/L. KMnO4 also was used to continuously regenerate the MnO2-
coated anthrasand in the filters. The new FeCl3 addition system consisted of a 1.75 gal/hr
(gph) chemical metering pump, a 60-gal chemical day tank, a tank mixer, and a
secondary containment skid. Figure 4-6 shows the new chemical feed system for FeCl3
that was installed as part of the process modifications.
Tray Aeration Rapid Mix Tank
ci-
Ferric Chloride
Baffled
Filtration
—
—
r
— t
KMnO4 Q}>
Polymer 1 | !.,_
Polymer 2 |V
_
. j^
J
i1""*
.
^
Supernatant
/B
R
r
>
ack
ecc
Ba
>
V
Bac
W
was
vet
sin
—" (4 Cells)
>
kwash
'ater
h\
y
— >
uuuu
I . . . ^
f
I I I I
LlDCiERV^jOGO PLA^
Water Reclaimed
to Rapid Mix Tank
Modification
Sludge
Tank
Sludge to Landfill •*•
Distribution
System
Figure 4-4. Process Schematic of Coagulation/Gravity Filtration Plant at Lidgerwood, ND
16
-------
Table 4-3. Design Specifications for Lidgerwood, ND Coagulation/Gravity Filtration Plant
Parameter
Value
Remarks
Pre- Treatment
Prechlorination Dosage (mg/L [as C12])
Potassium Permanganate Dosage
(mg/L)
Iron Dosage (mg/L [as Fe])
Aqua Hawk 9207 PWG Polymer
Dosage (mg/L)
Aqua Hawk 127 Polymer Dosage
(mg/L)
1.8
0.7
1.0-1.2
0.3
0.5
Based on Jar Test Results
Based on Jar Test Results
Based on Jar Test Results
Contact
Capacity (gal)
Contact Time (min)
15,000
60
At 250 gpm design flowrate
Filtration
Cell Size (ft)
Cell Area (ft2)
Number of Cells
Configuration
Media Quantity (ft3/cell)
Media Type
Design Flowrate (gpm)
Filtration Rate (gpm/ft2)
Ap across Clean Bed (in of H2O)
Maximum Daily Production (gpd)
Hydraulic Utilization (%)
7.0 Lx 4.3 W
30
4
Parallel
60
MnO2-coated
anthrasand
250
2.1
10
360,000
50
24-in bed depth
20/40 mesh
Based on peak flow; 24 hr/day
Estimated based on peak daily
demand(a)
Backwash
Backwash Frequency
Backwash Hydraulic Loading Rate
(gpm/ft2)
Backwash Duration (min/cell)
Wastewater Production (gal/cell)
3 time per week
8.0
10
2,400
Taking place on Monday, Wednesday,
and Friday
Based on 240 gpm backwash flowrate
(a) Based on a historic peak daily demand of 180,000 gpd.
Ferric chloride was added at a target dosage of 1.2 mg/L (as Fe). Two non-ionic
polymers also were added. Aqua Hawk 9207 PWG, a polyacrylamide-based polymer,
had already been added at the plant at a level of approximately 0.10 mg/L prior to this
demonstration study. During this study period, the dosage of this polymer was increased
to 0.3 mg/L at a feed rate of 0.90 gph. The second polymer added during this study
period was Aqua Hawk 127, which is a blended aluminum-based coagulation
chemical/polymer. It was added at a rate of 0.75 gph to reach a target level of 0.5 mg/L.
Both polymers are NSF International-certified for use in drinking water applications.
• Contact Time. The baffled detention tank had a capacity of 15,000 gal and allowed for
approximately 60 min of contact time before gravity filtration.
17
-------
Monthly
H temperature^), DCK3),
As (total and soluble), As (III),
As (V), Fe (total and soluble),
Mn (total and soluble),
Ca, Mg, F, N03, S04, SiO2, PO4,
turbidity, alkalinity
SUPERNATANT WATER
pH, TDS,
turbidity, As (soluble),
Fe (soluble), Mn (soluble)
Process Modification
Lidgerwood, ND
Oxidation/Coagulation/Filtration
Design Flow: 250 gpm
Weekly
pHO), temperature^3), DO), ORP<3),
• As (total), Fe (total), Mn (total),
SiO2, PO4, turbidity, alkalinity
KMnO4
Polymers
FeCl,
L3), temperature1:3), DO^), ORP^,
As (total and soluble), As (III),
As (V), Fe (total and soluble),
Mn (total and soluble),
Ca, Mg, F, N03, S04, SiO2, PO4,
turbidity, alkalinity
BAFFLED
DETENTION TANK
BACKWASH WATER
RECLAIM BASIN
MnO2-COATED
ANTHRASAND
FILTRATION
O), temperature^), OCX3),
As (total and soluble), As (III),
As (V), Fe (total and soluble),
Mn (total and soluble),
Ca, Mg, F, NO3, SO4, SiO2, PO4,
turbidity, alkalinity
S
_o
o
3
GO
S
1
S
(2)
(BF)
(2)
^c)
@
(ss)
DA: C12
INFLUENT
FeCl3
LEGEND
At Wellhead
Before Filter
After Filter
Post-Chlorination
Backwash Sampling Location
Sludge Sampling Location
Chlorine Disinfection
Unit Process
Chemical Added to Unit Process
Process Flow
Backwash Flow
SLUDGE TANK
TCLP,_
As (total)"
\
r
DA: C12
CLEARWELL
pH(a), temperature^), DCKa), ORP(a),
• As (total), Fe (total), Mn (total),
SiO2, PO4, turbidity, alkalinity
pH
-------
Figure 4-6. New Iron Addition System
• Gravity Filtration. Particulate matter in water was removed using four gravity filter
cells, each having a cross-sectional area of 30 ft2 and filled with 24-in of 20 x 40 mesh
MnO2-coated anthrasand (General Filter Products) that was changed out on October 31,
2002. The total cross-sectional area of all four cells was 120 ft2, which yields a hydraulic
loading rate of 2.1 gpm/ft2 at the design flowrate of 250 gpm. This hydraulic loading rate
is consistent with the 2 gpm/ft2 specification for conventional sand filters in the
Recommended Standards for Water Works or Ten State Standards (Great Lakes-Upper
Mississippi River Board of State Sanitary Engineers, 2003). The pressure drop was 10 in
of H2O across the clean filter cell in the service mode. As part of the process
modifications, each filter cell was outfitted with a Hach 1720D low-range turbidimeter
with a power supply and associated interface (see Figure 4-7). In addition, a Foxboro
differential pressure (Ap) cell was placed across the media bed in Filter Cell No. 4 to
monitor the filter cell performance. Data from these devices were recorded and stored by
a Telog data logging system and downloaded once per week by the operator.
• Post-Chlorination. For post-chlorination, free chlorine was targeted at 0.08 mg/L and
total chlorine residual was targeted at 3.4 mg/L. In addition, 1.3 mg/L of fluoride was
added to the treated water prior to distribution.
• Backwash Operation and Reclaim. A clock-based timer was used to trigger a
backwash every Monday, Wednesday, and Friday at 3 AM. Each backwash cycle
19
-------
4.3
included an initial air sparging step (air and water) with an air scour pressure of 3.5 Ib
followed by 12 min of backwash per cell at approximately 240 gpm. The backwash
water produced from each backwash cycle was allowed to settle in an 18,000-gal
backwash water reclaim basin for 6 hr. After the required settling period, the supernatant
was reclaimed to the mixing tank with a !/2-hp reclaim pump at a flowrate of 26 gpm.
This pump was later replaced by a 1-hp reclaim pump to reach a flowrate of 40 gpm to
increase the rate of recycling and allow for daily backwashing of the system, if needed.
The sludge accumulated in the bottom of the reclaim basin was pumped to a 20-ft
diameter by 9-ft, 5-in tall sludge holding tank and then collected for landfill disposal once
every other year. After the process modifications, the frequency of sludge disposal was
increased to once per year.
Figure 4-7. Turbidimeters and DataLogger for Process Measurements
• Clearwell Storage. Before distribution, the treated water was stored in a 30,000-gal
clearwell located underneath the treatment building. The original 16,000-gal clearwell
installed in 1984 was used as a source for backwash and the 30,000-gal clearwell
installed in 1989 was used for distribution water. The treated water was stored in a
50,000-gal water tower in town.
Process Modifications
Prior to the demonstration study period, several steps were taken to determine a set of process conditions
capable of reducing arsenic concentrations to less than the 10 |o,g/L MCL. These pre-demonstration
activities included treatment plant baseline testing, jar tests for iron and polymer additions, and
supplemental iron and polymer addition testing to achieve target conditions in the plant. The results of
these pre-demonstration activities are discussed below. These activities occurred prior to the
commencement of the full-scale performance evaluation study.
20
-------
4.3.1 Treatment Plant Baseline Sampling. Prior to the process modifications, speciation samples
were collected across the treatment train on January 14, 2004. The speciation results presented in
Table 4-4 showed that the ratio of soluble iron to soluble arsenic concentration in raw water was 8:1,
which was well below the target level of 20:1 for effective arsenic removal (EPA, 2001; Sorg, 2002).
Iron and manganese existed entirely in the soluble form. After prechlorination, aeration, and KMnO4
addition, arsenic, iron, and manganese were present primarily in the particulate form. The soluble arsenic
fraction consisted primarily of As(V) at 19.6 (ig/L, suggesting effective oxidation of As(III) to As(V).
Upon exiting the baffled detention tank, 19.4%, 16.7%, and 16.9% of particulate arsenic, iron, and
manganese, respectively, were removed through settling within the detention tank. The total arsenic level
in the filter effluent was 38.2 (ig/L, which was present primarily as As(V). There also was 5.5 (ig/L of
particulate arsenic in the filter effluent. The total arsenic level in the filtered effluent was consistent with
those in the treated water samples colleted by Battelle on July 31, 2003, and by NDDH from 1998
through 2003.
Table 4-4. Analytical Results of Baseline Speciation Samples Taken Across
Treatment Train on January 14, 2004
Parameter
As (total)
As (particulate)
As (soluble)
As (III)
As(V)
Fe (total)
Fe (soluble)
Mn (total)
Mn (soluble)
Free Chlorine (as C12)
Unit
Hg/L
Hg/L
Hg/L
UR/L
Hg/L
Hg/L
Hg/L
Hg/L
Hg/L
mg/L
At
Wellhead
153
13
140
121
19.0
1,053
1,075
668
673
NA
After
Aeration/
Rapid Mixing
145
124
20.6
1.0
19.6
1,025
<25
840
12.7
1.37(a)
Before
Filters
126
100
25.7
0.9
24.8
854
<25
698
1.1
0.92
After
Filters
38.2
5.5
32.7
0.9
31.8
<25
<25
7.8
2.2
0.06
Post-
Chlorination
40.2
7.6
32.6
1.0
31.6
<25
<25
6.1
1.4
0.10(2.20)(b)
(a) Permanganate in water might have interfered with chlorine measurements using Hach meter.
(b) Total chlorine reading in parentheses.
The baseline performance of Filter Cell No. 4 was further evaluated from February 2 through 6, 2004.
Figure 4-8 shows total and soluble arsenic concentrations in the Filter Cell No. 4 effluent during this
period. The filter run times were 14.9 hr from Monday to Wednesday (February 2 to 4, 2004) and 12.9 hr
from Wednesday to Friday (February 4 to 6, 2004).
Total arsenic levels in the filter effluent ranged from 25.8 to 39.7 |o,g/L and existed primarily in the
soluble form. Total iron levels were <25 |o,g/L in all effluent samples. Total manganese concentrations
averaged 3.7 |o,g/L and existed primarily in the soluble form. The presence of soluble arsenic in the filter
effluent confirmed the need for supplemental iron addition. The on-line baseline turbidity readings of the
Filter Cell No. 4 effluent averaged 0.032 nephelometric turbidity units (NTU), indicating effective
particulate removal by the filter (Figure 4-9).
4.3.2 Jar and Process Testing for Iron Addition. A series of jar tests was performed on-site by
Battelle in January 2004 using water taken from the wellhead and rapid mix tank. The jar test procedure
is summarized in Section 3.3.2. The objectives of the jar tests were to: 1) compare the effectiveness of
21
-------
0 -
02/01/04
02/02/04 02/03/04
02/04/04
Date
02/05/04 02/06/04 02/07/04 02/08/04
Figure 4-8. Total and Soluble Arsenic Levels in Filter
Cell No. 4 Effluent Under Baseline Conditions in February 2004
2/1
Baseline
Sampling
M
|
'
J
W F
Backwashes occured on Mondays, Wednesdays, and Fridays
F
M
M I . W F M F
• J i ^ »A.
/04 2/6/04 2/11/04 2/16/04 2/21/04 2/26/04 3/2
* •
!=
Figure 4-9. Turbidity Readings of Filter Cell No. 4
Effluent under Baseline Conditions in February 2004
22
-------
FeCl3 and FeSO4 for arsenic removal; 2) determine the optimal iron salt dosage to enhance arsenic
removal to below 10 |og/L; and 3) determine the effect of different iron addition points prior to the gravity
filters.
Figure 4-10 shows the results of the first and second jar tests with the addition of FeCl3 or FeSO4 to raw
water. With 0.9 to 1.0 mg/L (as Fe) of iron addition, arsenic concentrations were reduced to 16.9 to 26.2
Hg/L and iron concentrations, unexpectedly, to only 83.9 to 210 |o,g/L in 0.45 (im-filtered water. Because
the contents in the jars were in contact with air for at least 30 min and because chlorine residuals were
measured in the jars by the end of tests, it would not have been possible to have soluble iron present in
filtered water. It was, therefore, speculated that some iron particles might have passed through 0.45 jam
disc filters due to smaller sizes of these particles.
40
•
"5)
i
u" 25
loo
< ^
m
n
Ferric Chloride
• FerrousSulfate
^^
N^
V
^^
\^
^^
Note:
Contact Time: SOmin
pH(before): 7.14-7.15
Disc Fill erUsed:0.45nm
0.0
0.2
0.4
0.6
Iron, mg/L
0.8
1.0
1.2
Figure 4-10. Results of Jar Tests with Addition of FeCl3 or FeSO4 to Raw
Water (Tests Performed by Battelle)
Figure 4-11 shows the results of the third and fourth jar tests with the addition of FeCl3 or FeSO4to water
collected from the rapid mix tank. With 0.45 to 0.51 mg/L (as Fe) of iron addition, soluble arsenic
concentrations were reduced to 17.8 to 21.3 |o,g/L. In this case, iron levels were reduced to <25 |o,g/L.
Apparently, the amounts of iron added during each of the four jar tests were not sufficient to remove
soluble arsenic to below 10 |o,g/L.
EPA subsequently conducted a series of jar tests off-site using water collected from the clearwell with
different dosages of FeSO4 and Fe2(SO4)3. Upon completion of the jar tests, both 0.45 and 0.20 jam disc
filters were used to filter the water samples. The results of these jar tests, as shown in Figure 4-12,
indicated that about 1.0 to 1.2 mg/L (as Fe) of iron would be needed to reduce soluble arsenic
23
-------
Arsenic, |ag/L
45
4n
•55
on
m
c
n
Ferric Chloride
• FerrousSulfate
^*-\
^~ * ^^*
Note:
Contact Time: GOmin
pH(before):7.50-7.59
Disc Filter Used: 0.45p.m
0.0
0.1
0.2
0.3
Iron, mg/L
0.4
0.5
0.6
Figure 4-11. Jar Test Results with Addition of FeCl3 or FeSO4 to Water
Collected from Rapid Mix Tank (Test Performed by Battelle)
concentrations to below 10 |o,g/L. The data also showed that using 0.20 jam disc filters resulted in much
lower arsenic concentrations, compared to the data using 0.45 jam disc filters, confirming that some
fractions of arsenic particulate were indeed smaller that 0.45 jam (Lytle, 2005).
The process conditions for supplemental iron addition were determined based on the jar test results
obtained by Battelle and EPA. FeCl3 was selected as the chemical for supplemental iron addition. FeCl3
provided comparable arsenic removal performance to FeSO4 and Fe2(SO4)3 and was readily available
from the City's chemical supplier. FeCl3 was available in a more concentrated form at 35%, which would
be more convenient to use for solution preparation than FeSO4 at 7%. Moreover, the use of FeSO4 or
Fe2(SO4)3 would have contributed to the already elevated sulfate levels (i.e. about 390 mg/L) in the
treated water. Further, FeSO4 has an elevated freeze point compared to FeCl3, which may add complexity
to shipping, storage, and handling, especially under sub-zero ambient conditions in the winter. The
supplemental iron dosage was determined to be between 1.0 to 1.2 mg/L (as Fe) to reduce arsenic below
10 ng/L. The rapid mix tank was selected as the point for the FeCl3 injection.
Supplemental iron addition was tested on the full-scale system from March through July 2004. During
this time period, 142 samples were collected approximately twice per day, five days a week. Table 4-5
summarizes total and soluble arsenic and iron concentrations in the Filter Cell No. 4 effluent with the
addition of 0.6 to 1.1 mg/L (as Fe) of FeCl3 and 0.10 to 0.12 mg/L of Aqua Hawk 9207 PWG (i.e., the
polymer already used at the plant prior to the demonstration study). All soluble arsenic and iron samples
were collected using 0.22 jam disc filters. As shown in the table, average total arsenic levels in the filter
effluent ranged from 16.3 to 23.9 |o,g/L and average total iron levels ranged from 32 to 139 |o,g/L. When
only 0.6 to 0.9 mg/L of iron was added (i.e., from March 9 to June 30, 2004), average soluble arsenic
24
-------
oo o.2 0.-4 0.6 o.e
Iron, mg/L
(pH at 7.67 with 30 mln of contact time)
1.0 1,2
Figure 4-12a. Jar Test Results for FeSO4 to Water Collected from Clearwell
(Test Performed by EPA)
0 0.2 0.4 0.6 US 1.0 1.2
Iron, mg/L
(pH at 7.67 with 30 min of contact time)
Figure 4-12b. Jar Test Results for Fe2(SO4)3 to Water Collected from Clearwell
(Test Performed by EPA)
levels remained high, ranging from 14.0 to 16.5 |ag/L. From July 1 to 31, 2004, as the iron dosage was
increased to 1.1 mg/L (as Fe), the average soluble arsenic level was reduced to 8.7 |ag/L. Particulate
arsenic and iron breakthrough from the filter apparently had caused total arsenic levels in the filter
effluent to exceed the 10 |o,g/L target level.
25
-------
Table 4-5. Arsenic and Iron Levels in Filter Cell No. 4 Effluent
During Iron Addition Process Testing
Test Duration
03/09/04-03/19/04
04/07/04-05/18/04
06/14/04 - 06/30/04(a)
07/01/04-07/31/04
Average
Iron
Dosage
(mg/L
[as Fe])
0.6
0.9
0.9
1.1
Average
Aqua
Hawk
9207PWG
Dosage
(mg/L)
0.10
0.10
0.12
0.12
No. of
Samples
15
60
24
43
Average
As
(total)
(Hg/L)
18.6
23.9
18.5
16.3
Average
As
(soluble)
(Hg/L)
15.1
16.5
14.0
8.7
Average
Fe
(total)
(Hg/L)
32
81
54
139
Average
Fe
(soluble)
(Hg/L)
<25
<25
<25
<25
(a) Aqua Hawk 9207 PWG application rate was increased on June 21, 2004 from approximately
0.10 mg/L to 0.12 mg/L.
Figure 4-13 shows total arsenic levels in the Filter Cell No. 4 effluent from July 1 through 31, 2004, when
an average of 1.1 mg/L of iron was added. Total arsenic levels ranged from 8.2 to 40.1 |o,g/L and
averaged 16.3 |og/L, with the majority of arsenic present as particulate arsenic with levels ranging from
0.2 to 29.7 |og/L. Total iron concentrations ranged from <25 to 557 |o,g/L and averaged 139 |og/L, which
was present entirely in the particulate form (data not shown). These results further demonstrated that iron
particles formed prior to the gravity filters were not effectively removed by the MnO2-coated anthrasand.
The turbidity readings of the filter effluent (that will be discussed further in Section 4.5.1.4) averaged
0.31 NTU during this time period, compared to the average baseline turbidity value of 0.032 NTU.
Nevertheless, the Ap readings recorded just before respective backwash cycles ranged from 25.4 to 44.6 in
of H2O, which were comparable to the baseline levels of 26.2 to 41.4 in of H2O recorded in February
2004. These data will be further discussed in Section 4.4.1.
•a 50-
"o >"o
o o
\ \
Figure 4-13. Total and Soluble Arsenic in Filter Cell No. 4 Effluent with
Supplemental Iron Addition in July 2004
26
-------
4.3.3 Jar and Process Testing for Polymer Addition. A series of jar tests was performed on-site
in August 2004 by the Hawkins Water Treatment Group (the City's chemical supplier) to determine if
supplemental polymer addition could provide improved particulate arsenic and iron removal across the
MnO2-coated anthrasand filters. A total of eight different combinations of polymers were tested. The
results presented in Table 4-6 showed total arsenic levels ranging from 5.8 to 7.3 |o,g/L and soluble arsenic
levels ranging from 5.6 to 7.1 |o,g/L in the treated water. (Note that soluble arsenic samples were filtered
with 0.22 jam disc filters.) The combination of Aqua Hawk 127 at 0.5 mg/L and Aqua Hawk 9207 PWG
at 0.3 mg/L showed both total and soluble iron levels at non-detectable levels and, therefore, was selected
for full-scale plant process testing. The Aqua Hawk 9207 PWG had already been used at the treatment
plant prior to the process modifications, but at a lower dose rate of approximately 0.10 mg/L. Based on
these jar test results and the iron addition process testing, the target process conditions were set at
1.2 mg/L (as Fe) for supplemental FeCl3 addition, 0.5 mg/L for Aqua Hawk 127, and 0.3 mg/L for Aqua
Hawk 9207 PWG. After the polymer jar tests were completed, the results were shared with the project
team and approval was received from NDDH for full-scale plant testing. The operator set up a second
polymer feed system on September 21, 2004.
Table 4-6. Summary of Polymer Jar Test Results Obtained in August 2004
Jar
Test
No.
1
2
3
4
5
6
7
8
Polymer Mix
-------
Table 4-7. Summary of Macrolite® Pilot Test Analytical Results
Test
Run
Time
(hr)
Average
Flowrate
(gpm)
Average
Total As
Influent
(ne/L)
Average
Total As
Effluent
(Hg/L)
Average
Total Fe
Influent
(Hg/L)
Average
Total Fe
Effluent
(Hg/L)
Average
Total Mn
Influent
(Hg/L)
Average
Total Mn
Effluent
(Hg/L)
Test 1: Water before fitter with NaOCl, KMnO4, FeCl3, and polymers
Runl
Run 2
Run3
Ave
8.4
8.6
9.1
8.7
2.00
1.98
2.00
1.99
66.5
72.6
73.1
70.7
7.6
6.0
6.3
6.6
1,287
1,371
1,381
1,346
<25
<25
<25
<25
60.8
61.2
61.6
61.2
75.4
20.5
28.0
41.3
Test 2: Raw water with KMnO4 only
Runl
Run 2
Run3
Ave
10.3
10.2
10.0
10.1
1.99
1.99
1.99
1.99
110
106
102
106
11.4
12.1
11.8
11.8
1,610
1,508
1,396
1,505
<25
<25
<25
<25
1,786
1,637
1,502
1,642
29.2
12.3
43.1
28.2
During the first pilot test, influent total arsenic levels averaged 70.7 |o,g/L and the effluent total arsenic
levels averaged 6.6 |o,g/L. Arsenic in the filter effluent was present almost entirely in the soluble form
with an average value of 6.5 |o,g/L. There were no detections of total iron in the filter effluent. Total
manganese averaged 61.2 |o,g/L in the influent and 41.3 |o,g/L in the effluent. Manganese was present in
both the particulate and soluble form. Soluble manganese levels averaged 38.5 |o,g/L in the influent and
35 |og/L in the effluent. Only particulate manganese was removed by the Macrolite® filter. These data
indicate that the Macrolite® filter media was effective in removing arsenic, iron, and manganese
particulates at 91%, 100%, and 33%, respectively. Soluble manganese was not removed across the filter
as observed with the MnO2-coated anthrasand media.
Figure 4-15 shows the headless versus time for each of the three runs during the first and second pilot
test. During the first pilot test, the Ap readings across a clean filter (right after backwash) ranged from
37.8 to 39.8 in of H2O and the Ap readings across a loaded filter just before backwash ranged from 100.5
to 101 in of H20. This represents an average increase of 62 in of H2O over the duration of filter runs,
which averaged 8.7 hr between consecutive backwash events. Based on the Ap measurements and run
length, the average rate of Ap buildup was 7.1 in of H2O/hr, which was more than 2.5 times higher than
the rate of Ap buildup observed, i.e., 2.7 in of H2O/hr, in the full-scale plant (see Section 4.4.1). If the
system was retrofit with the use of Macrolite® filter media, this higher rate of Ap buildup would have
resulted in the need for more frequent backwashing than already employed at the treatment plant.
During the second pilot test, influent total arsenic levels averaged 106 |o,g/L (see Table 4-7), which was
significantly higher than the influent arsenic level in the first pilot test, due to the particulate arsenic
removal that occurred within the baffled detention tank in the full-scale treatment plant (see Figure 4-14).
Total arsenic levels in the Macrolite® filter effluent averaged 11.8 |o,g/L, which was present entirely in the
soluble form. Supplemental iron was needed to achieve an arsenic level below 10 |og/L, but was not used
during the pilot test due to the vendor's time and equipment constraints. There were no detections of total
iron in the filter effluent. Total manganese levels averaged 1,642 |o,g/L in the influent and 28.2 |o,g/L in
the effluent. The vendor encountered difficulty in controlling the KMnO4 dosage to the pilot test
apparatus and adjustments were made during the pilot test to the KMnO4 dosages. Soluble manganese
levels averaged 50 |o,g/L in the influent and 26.5 |o,g/L in the effluent. These data indicated that the
Macrolite® filter was effective in retaining arsenic, iron, and manganese particulates. However,
supplemental iron addition was required to achieve arsenic levels below 10 |o,g/L.
28
-------
120
110 -
100 -
90 -
40 -
30 -
20 -
10
0 -
03/31/05
Date
Figure 4-14. Total and Soluble Arsenic Concentrations During Macrolite® Pilot Tests
•
•
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Test 2:
Raw Water + KMnO4
04/04/05 04/06/05
Date
Figure 4-15. Headloss Across Macrolite® Filter During Pilot Tests
29
-------
During the second pilot test, the Ap readings across a clean filter ranged from 32.5 to 34.0 in of H2O and
across a loaded filter from 100 to 101.5 in of H20. This represents an average increase of 67.7 in of H2O
over the duration of filter runs, which averaged 10.1 hr between consecutive backwash events. The run
length achieved was only 1.4 hr longer in duration than the first pilot test with supplemental additions of
both iron and polymer. Based on the Ap measurements and run length, the average rate of Ap buildup
was 6.7 in of H2O/hr, which was still significantly higher than the rate of Ap buildup observed (i.e., 2.7 in
of H2O/hr) in the full-scale plant.
Based on the pilot test results, it was determined that a retrofit to the existing gravity filtration plant with
the Macrolite® media would not benefit the system operations. The rate of Ap buildup from 6.7 to 7.1 in
of H2O/hr across the Macrolite® bed represented a significant increase in headless, which would require
much more frequent backwashing of the filters than already necessitated for the full-scale treatment plant.
Further, the initial headless at 36 in of H2O across the clean Macrolite® bed was higher than the 10 in of
H2O initial headless across the MnO2-coated anthrasand bed. The final headless at 101 in of H2O was
also higher than observed in the full-scale plant with the final headless ranging from 29.2 to 91.7 in of
H2O at the end of the filter run cycles. Therefore, the increased rate and magnitude of headless buildup
would necessitate more frequent backwashing with Macrolite® media.
4.3.5 Summary of Process Modifications. The initial process modifications included the
installation of an iron addition system (including a drum scale to measure FeCl3 solution consumption),
four turbidimeters to monitor the turbidity of the effluent from the four filter cells, and a differential
pressure transducer to monitor headless across Filter Cell No. 4. The engineering package for the initial
process modifications, including a process design report, a piping and instrumentation diagram (P&ID), a
general arrangement diagram, a turbidity meter interconnect schematic, and an electrical schematic, was
submitted to NDDH for review on November 17, 2003. A letter from NDDH providing approval to
install the iron addition system was received on December 8, 2003. The primary installation activities
included placing the FeCl3 tank on the drum scale and spill containment deck, mounting the tank mixer
and pump to a wall bracket, and connecting the tubing from the chemical metering pump to the injection
point at the rapid mix tank. The installation activities also included all electrical connections and
calibration of the associated instrumentation including the drum scale, turbidimeters, and differential
pressure transducer. The iron addition system installation was completed on January 14, 2004.
After the iron addition process testing and polymer jar tests were completed in August 2004, a second
polymer addition system was installed on September 21, 2004, for the Aqua Hawk 127 polymer addition.
An existing spare chemical feed pump and tank were used and a new tank mixer was purchased for the
second polymer feed system. Additional changes were later made at the treatment plant based on recom-
mendations developed from the demonstration study results. These changes included: 1) installing a
larger 1-hp backwash reclaim pump to provide a 40 gpm capacity to facilitate daily backwash events,
2) implementing a more frequent backwash schedule, and 3) reducing the wellhead pump rate to more
closely match the design specification for the hydraulic loading rate to the filters. The 40-gpm reclaim
pump was installed at the plant on October 18, 2005. The wellhead flowrate was reduced to an average
value of 239 gpm, which, after including the 40 gpm reclaim flowrate, would yield a hydraulic loading
rate of 2.3 gpm/ft2. The operator also implemented backwashing over the weekends in October 2005 with
daily backwashing to be used as water demand increased in the spring and summer months.
4.4 System Operation
4.4.1 Operational Parameters. Table 4-8 summarizes the operational parameters including
operational time, throughput, flowrate, and differential pressure readings. Detailed daily operational data
are attached as Appendix A. The plant operational data were recorded from January 1, 2005, through
July 31,2005.
30
-------
Table 4-8. Summary of System Operation at Lidgerwood, ND
Parameter
Operational Period
Total Operating Time (hr)
Average Daily Operating Time (hr)
Range of Daily Operating Times (hr)
Throughput from Wells (gal)
Average Daily Demand to Distribution (gpd)
Peak Daily Demand to Distribution (gpd)
Average Well Flowrate (gpm)
Range of Well Flowrates (gpm)
Average Reclaim Flowrate (gpm)
Range of Contact Times in Detention Tank (min)(a)
Range of Hydraulic Loading Rates to Filters (gpm/ft2)(a)
Number of Backwash Events
Median Run Time between Backwash Cycles (hr)
Median Throughput between Backwash Cycles (gal)
Range of Run Times between Backwash Cycles (hr)
Range of Throughputs between Backwash Cycles (gal)
Range of Ap Readings at Beginning of Filter Run (in of H2O)
Range of Ap Readings at End of Filter Run (in of H2O)
Values
01/01/05-07/31/05
1,300
6.1
2.3-12.3
22,102,000
89,788
173,000
283
217-298
26
46-62
2.0-2.7
97
13.3
225,834
8.7-27.2
147,726-461,856
6.4-13.2
29.2-91.7
(a) Well flowrate and reclaim flowrate included for calculations.
From January 1, 2005, through July 31, 2005, the treatment system operated for approximately 1,300 hr,
with an average daily operating time of 6.1 hr/day based on the treatment plant hour meter readings. The
total system throughput was approximately 22,102,000 gal based on the flow totalizer readings. The
average daily demand was approximately 89,788 gal and the peak daily demand occurred on July 22,
2005, at 173,000 gal, which was very close to the historic peak daily demand of 180,000 gal. The
flowrates from the wells ranged from 217 to 298 gpm and averaged 283 gpm based on the plant totalizer
and hour meter readings. The average reclaim rate was 26 gpm for the recovery of backwash water.
These flowrates corresponded to 46 to 62 min, with an average value of 49 min, of contact time within the
baffled detention tank. At these flowrates, the hydraulic loading rates to the filters ranged from 2.0 to
2.7 gpm/ft2, compared to the 2.1 gpm/ft2 design value for the plant. One of the recommendations of the
demonstration study was to decrease the flowrate from the wells to provide for a lower hydraulic loading
rate to the filters.
During the seven-month demonstration period, a total of 97 backwash events took place. The run times
between two consecutive backwash events ranged from 8.7 to 27.2 hr and the corresponding throughputs
from 147,726 to 461,856 gal of raw water (e.g. without reclaim). The median run time value was 13.3 hr
and the corresponding median value of raw water throughput was 225,834 gal between two consecutive
backwash cycles.
4.4.1.1 Differential Pressure and Filter Run Time. A differential pressure transducer was used to
monitor Ap across Filter Cell No. 4 during the filter service cycles. Typical on-line Ap readings are
shown: (1) in Figure 4-16 for baseline conditions before the process modifications in February 2004; and
(2) in Figure 4-17 for conditions after the process modifications (i.e., with supplemental iron and polymer
additions) in February 2005. The data in Figure 4-16 and Figure 4-17 are summarized in part of Table 4-
9.
31
-------
Figure 4-16. Typical Ap Readings Across Filter Cell No. 4 Under
Baseline Conditions in February 2004
Figure 4-17. Typical Ap Readings across Filter Cell No. 4 After
Process Modifications in February 2005
32
-------
Table 4-9. Summary of Ap Buildup Across Filter Cell No. 4
Time
Range of
Apinitial
(inofH2O)
Median
Apinitial
(inofH2O)
Range
Apfinai
(inofH2O)
Median
Apfinai
(inofH2O)
Median
Ap Buildup
(inofH2O)
Range
of
Filter
Run
Times
(hr)
Median
Filter
Run
Time
(hr)
Average
Rate of Ap
Buildup
(in of
H2O/hr)
Under Baseline Conditions in February 2004
02/04
9.8-10.7
10.3
26.2-41.4
29.7
19.0
11.7-23.9
15.2
1.3
After Process modifications from January to July 2005
01/05
02/05
03/05
04/05
05/05
06/05
07/05
9.8-12.5
9.5-12.9
6.4-12.9
9.8-13.2
9.4-12.9(a)
9.4-28.7(a'b)
9.3-12.6
9.9
10.0
10.0
10.2
10.1
9.9
10.0
29.2-66.5
38.9-71.4
32.5-60.0
33.4-89.0
33.5-55.2
41.2-68.8
38.3-91.7
40.4
51.4
42.3
60.8
42.3
49.3
55.2
30.5
41.3
31.9
49.2
32.5
39.0
45.3
11.6-20.0
12.0-20.3
11.5-19.6
10.0-21.0
8.7-17.2
8.8-16.2
10.4-27.2
12.6
14.5
12.7
13.1
11.7
13.6
16.8
2.2
2.8
2.4
3.3
2.7
2.8
2.7
(a) Data from May 20 to 30, 2005, June 8 to June 19, 2005, and June 22 to 30, 2005, were not available due to
problems with downloading files from datalogger.
(b) Including data from June 20 to 21, 2005, during which filter plugging occurred after a run time of 8.8 hr due to
an incomplete filter backwash. These data were not included in the median calculations for the month of June
2005.
These figures show changes in Ap over time with initial Ap readings (Apimtiai) starting at a low level of
approximately 10 in of H2O across a clean bed. Subsequently, Ap increased steadily with each filter run
(note that low level at the water tower triggered three to four filter runs per day) as particulates were
accumulating in the filter bed. The highest Ap readings occurred at the end of the final filter runs just
prior to backwash every Monday, Wednesday, and Friday. As expected, the additional filter runs over the
weekends (i.e., from Fridays to Mondays) resulted in elevated final Ap readings (Apfmal), compared to
those during the weekdays.
To further dissect the Ap data shown in Figure 4-16 and summarized in Table 4-9, 10 sets of Ap readings
representing 10 sets of consecutive filter runs were included under baseline conditions. The Apmitial
readings across the filter ranged from 9.8 to 10.7 in of H2O (with a median value of 10.3 in of H2O)
immediately after backwash and at the start of subsequent filter runs. The Apfinai readings ranged from
26.2 to 41.4 in of H2O (with a median value of 29.7 in of H2O) at the end of filter runs. Slightly higher
Apfinai readings were associated with filter runs over the weekends (between Mondays to Fridays). During
February 2004, the filter run times ranged from 11.7 to 23.9 hr. As such, the rate of Ap buildup across the
filter was approximately 1.3 in of H2O/hr of operation under baseline conditions.
Table 4-9 also summarizes the Ap readings across Filter Cell No. 4 during the demonstration study with
supplemental iron and polymer additions from January to July 2005 including the February 2005 data
presented in Figure 4-17. The Apmitial readings ranged from 6.4 to 13.2 in of H2O (with a median value of
10.0 in of H2O), suggesting that backwash was effective in returning the filter to the initial low headless
conditions. These data also were comparable to those under baseline conditions with a median initial
Apimtiai reading of 10.3 in of H20 in February 2004. There was one event on June 20, 2005, when the
operator reported an incomplete backwash that led to an elevated Apmitiai reading of 28.7 in of H2O. After
amanual backwash on June 21, 2005, the Apmitiai reading returned to 11.7 in of H2O.
33
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The Apfinai readings across the filter cell ranged from 29.2 to 91.7 in of H2O. The higher Apfmai values,
ranging from 41.5 to 91.7 in of H2O, were associated with the additional filter runs and long filter run
times over the weekends, ranging from 11.7 to 27.2 hr and averaging 18.1 hr. The median Apfmai readings
ranged from 40.4 in of H2O in January 2005 to 60.8 in of H2O in April 2005. The median value over the
entire study period was 47.3 in of H2O, compared to a baseline median Apfmai value of 29.7 in of H2O in
February 2004. During the weekdays, the filter run times ranged from 8.7 to 22.7 hr and averaged 13.0
hr. Using the media Ap buildup and median run time for each month, the average rate of Ap buildup was
calculated to be 2.7 in of H2O/hr, which was two times higher than that under the baseline conditions in
February 2004. The higher rate of Ap buildup suggests that the filter bed may need to be backwashed
more often in order to meet the 10 |o,g/L MCL.
One recommendation was to limit the Apfmal to no higher than 50 in of H2O and the filter run time to no
longer than 15 hr. The 15-hr maximum filter run time was derived by dividing 40 in of H2O (i.e.,
assuming Apimtiai at 10 in of H2O) by 2.7 in of H2O/hr (i.e., the average rate of Ap buildup with
supplemental iron and polymer additions and at the well and reclaim flowrates of 283 and 26 gpm,
respectively). This is equivalent to a raw water throughput from the wellhead of 254,700 gal. The filter
run time could be extended to 20.2 hr if the wellhead flowrate was reduced to 210 gpm (with a reclaim
flowrate at 40 gpm) to reach the design value of 250 gpm. The shorter filter run times would require an
increase in backwash frequency, which would result in better plant performance especially in the spring
and summer months as the water demand increases. In order to allow for more frequent (such as daily)
backwash, further modifications to the treatment plant were required as discussed in Section 4.3.5.
4.4.1.2 Filter Backwash. During the demonstration study, the gravity filters were backwashed at
least three times per week using a clock-based timer triggered for Mondays, Wednesdays, and Fridays at
3 AM. The operator could perform a manual backwash, if needed. Backwash samples were collected
during manual backwash events performed on March 23, April 18, May 25, June 21, and July 25, 2005.
The plant also was manually backwashed on June 23, July 5, July 12, July 19, July 24, and July 30, 2005.
The operational parameters associated with the backwash events are summarized in Table 4-10.
From January 1, 2005, to July 31, 2005, 1,206,650 gal of backwash water was generated for reclaim to the
head of the treatment train. This represents a backwash water generation rate of approximately 5.5%
given the total volume of water pumped from the wells during this time period. Based on the backwash
pump hours, the average backwash flowrate was 272 gpm (or 9 gpm/ft2), which was higher than the
design value of 240 gpm (or 8 gpm/ft2). The average duration of each backwash event was 11 min for
each cell or 44 min for all four cells, which generated 2,989 gal from each cell or 11,957 gal from all four
cells. The backwash water was stored in the 18,000-gal backwash reclaim basin to settle for 6 hr before
the supernatant was reclaimed at 26 gpm to the rapid mix tank. At this flowrate, the plant needed over 7.5
hr of filter run time to recycle the approximately 12,000 gal backwash water produced from each
backwash cycle. Recall that the average daily run time of the system was only 6.1 hr, along with the 6-hr
settling time required; this essentially eliminated the possibility of having daily backwash as the plant.
The !/2-hp reclaim pump was replaced on October 18, 2005, with a 1-hp, 40 gpm-rated pump. The
increased flowrate would complete the recycling in 5 hr, thus giving the plant needed flexibility for more
frequent backwash (such as daily) during higher demand times. The 40 gpm reclaim flowrate increased
the reclaim ratio from 9.2% to 16.7%, which was approved by the NDDH on October 5, 2005.
4.4.2 Residual Management. Residuals produced by the operation of the coagulation/gravity
filtration plant included backwash water and sludge. The backwash water was discharged to the reclaim
tank and then reclaimed to the treatment system. As discussed in Section 4.4.1.2, the size of the reclaim
basin at 18,000 gal and the capacity of the reclaim pump at 26 gpm limited the treatment system to
backwashing every other day. The reclaim pump was later replaced with a 40-gpm pump in October
2005. The sludge from the reclaim tank was accumulated in a sludge holding tank and then collected for
34
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Table 4-10. Summary of Backwash Parameters
Backwash Parameters
Number of Backwash Events
Backwash Water Generated for Reclaim (gal)
Backwash Water Generation Rate (% )
Backwash Pump Operation (hr)
Average Backwash Flowrate (gpm)
Average Backwash Duration Per Cell (min)
Average Backwash Water Quantity Generated Per Cell (gal)
Average Backwash Water Quantity Per Cycle (gal)
Average Backwash Reclaim Pump Flowrate (gpm)
Value
97
1,206,650
5.5
73.9
272
11
3,110
12,440
26
landfill disposal once every other year. In addition, due to significant settling of solids prior to the filters,
it was necessary to clean the 15,000-gal baffled detention tank on an annual basis. The frequency of
sludge removal from the sludge holding tank also was increased from annually to biannually after the
process modifications had been implemented.
4.4.3 System/Operation Reliability and Simplicity. The major operational issue encountered
was related to the need to increase the backwash frequency to maintain filter performance as described in
Section 4.4.1. Neither scheduled nor unscheduled downtime had been required since the start of system
operations on January 1, 2005. The required system operation and operator skills are discussed according
to pre- and post-treatment requirements, chemical/media handling and inventory, levels of system
automation, operator skill requirements, and preventive maintenance activities.
4.4.3.1 Pre- and Post-Treatment Requirements and Chemical Handling/Inventory Requirements.
Pre-treatment requirements included prechlorination, aeration, and KMnO4 addition for oxidation of
As(III) and Fe(II), supplemental iron addition to enhance arsenic removal from raw water, and polymer
coagulant addition to enhance filterability of the floes formed. Post-treatment requirements at the site
included post-chlorination and fluoridation. Two additional chemicals, i.e., FeCl3 and Aqua Hawk 127,
were required as part of the process modifications. The operator checked the usage of the FeCl3
chemical consumption with a digital scale each day as part of the routine operational data collection. The
use of the Aqua Hawk 127 was checked daily through monitoring the tank level with a yard stick. The
FeCl3 and second polymer tanks were replenished approximately once per week. Similar to most
coagulation/filtration plants, the existing treatment plant had a high level of pre- and post-treatment
requirements.
4.4.3.2 System Automation. All major functions of the treatment system were automated and would
require only minimal operator oversight and intervention if all functions operated as intended. Automated
processes included system startup in the forward feed mode when the well energized, backwash cycling
based on a calendar frequency, system shutdown when the well pump shut down, and backwash water
reclaim. The automated backwash control clock was replaced prior to the demonstration study on
November 12, 2004 since the original component was no longer functional at the start of the project. One
observation was that the calendar-based backwash clock (e.g. backwash every Monday, Wednesday, and
Friday) did contribute to operational issues by limiting the flexibility associated with increasing the
backwash frequency. A treatment plant automated with backwash events based on throughput, filter run
time, or differential pressure would have been easier to control. The design of the pre-existing treatment
plant and controls limited the frequency of the automatic filter backwash events to every Monday,
Wednesday, and Friday, which impacted filter performance over the longer weekend filter runs.
35
-------
4.4.3.3 Operator Skill Requirements. The skill set required to operate the gravity filtration system
was high and included observation of the process equipment integrity and operating parameters such as
headless, flow, and system alarms. The O&M of the system required a significant level of mechanical
and electrical skills to ensure proper operation of pumps, controls, and other system components. The
operator needed a strong working understanding of chemical feed system O&M. The plant operator was
well versed in the operation of chemical addition systems for prechlorination, KMnO4 addition, and
polymer addition. These tasks included pump setup, maintenance to ensure the pump kept its prime, and
weekly chemical feed solution preparation. These tasks required a solid foundation in water chemistry
and calculations related to drinking water processes. However, the process modifications to add two
additional chemical feed systems did not significantly increase the daily demand on the operator in plant
O&M activities. The additional labor required included replenishing the ferric chloride solution tank and
the second polymer solution tank once per week. Other skills needed included performing O&M
activities such as cleaning and calibrating the filter cell turbidimeters and downloading files from the
Telog data logging system.
4.4.3.4 Preventive Maintenance Activities. Preventive maintenance tasks included daily to monthly
visual inspection of the piping, valves, filter cells, totalizers, and other system components. No
significant repairs were required during the study period. The backwash control clock was replaced prior
to the demonstration study on November 12, 2004, since the original component was no longer functional
at the start of the project. The hour meter for the reclaim pump was replaced on April 27, 2005.
4.5 System Performance after Process Modifications
The performance of the process modifications was evaluated based on analyses of water samples
collected from the treatment plant, backwash lines, and distribution system.
4.5.1 Treatment Plant Sampling. After the target process conditions were established, the
demonstration study began on January 1, 2005, and ended on July 31, 2005. The treatment plant water
was sampled on 31 occasions, including one duplicate sampling event. Field speciation also was
performed for seven of the 31 occasions. Table 4-11 summarizes the arsenic, iron, and manganese
analytical results. Table 4-12 summarizes the results of the other water quality parameters. Appendix B
contains a complete set of analytical results for the seven month duration of system operations. The
results of the water samples collected throughout the treatment plant are discussed below.
4.5.1.1 Arsenic Removal. Figure 4-18 shows the total arsenic levels across the treatment train over
the duration of the study period. Total arsenic levels in raw water ranged from 113 to 158 |o,g/L and
averaged 129 |o,g/L. As(III) was the predominating species with concentrations ranging from 116 to 130
Hg/L and averaged 125 |o,g/L (see bar charts in Figure 4-19 for speciation results). After the detention
tank and prior to the filters, As(III) concentrations ranged from <0.1 to 3.5 |o,g/L and averaged 1.8 |o,g/L,
suggesting effective oxidation of As(III) to As(V) with chlorine and potassium permanganate. After
detention and prior to the filters, total arsenic levels ranged from 59.2 to 105 |o,g/L and averaged 79.5
Hg/L, indicating arsenic removal of 38% through settling within the baffled detention tank. The
remaining arsenic after the detention tank was present primarily in the particulate form with levels
ranging from 52.7 to 98.0 |o,g/L and averaged 72.8 |o,g/L. The As(V) concentrations after the detention
tank averaged 4.1 |o,g/L, which indicated sufficient supplemental iron addition. After Filter Cell No. 4,
total arsenic levels were reduced to 6.3 to 14.3 |o,g/L and averaged 8.5 |o,g/L in the treated water, which
was present primarily in the soluble As(V) form with an average value of 5.7 |o,g/L. Particulate arsenic
levels in the treated water ranged from <0.1 to 4.9 |o,g/L, indicating some penetration of particulates
through the filter bed.
36
-------
Table 4-11. Summary of Arsenic, Iron, and Manganese Analytical Results
Parameter
As (total)
As (soluble)
As (paniculate)
As(III)
As(V)
Fe (total)
Fe (soluble)
Mn (total)
Mn (soluble)
Sampling
Location
IN
BF
AF
PC
IN
BF
AF
PC
IN
BF
AF
PC
IN
BF
AF
IN
BF
AF
IN
BF
AF
PC
IN
BF
AF
PC
IN
BF
AF
PC
IN
BF
AF
PC
Sample
Count
31
31
31
31
7
7
7
7
7
7
7
7
7
7
7
7
7
7
31
31
31
31
7
7
7
6
31
31
31
31
7
7
7
6
Concentration (u.g/L)
Minimum
113
59.2
6.3
6.0
117
4.3
3.7
7.5
<0.1
52.7
<0.
<0.
116
<0.
<0.
<0.
2.9
3.6
737
801
<25
<25
532
<25
<25
<25
567
452
1.1
0.9
598
5.8
1.1
1.2
Maximum
158
105
14.3
14.0
146
7.4
9.0
9.8
9.3
98.0
4.9
0.5
130
3.5
3.1
15.7
5.6
6.8
2,606
2,389
64.0
194
1,524
<25
105
<25
1,067
1,031
146
162
868
31.1
52.1
146
Average
129
79.5
8.5
8.4
132
5.9
7.4
8.4
4.3
72.8
1.1
0.1
125
1.8
1.7
7.0
4.1
5.7
1,344
1,575
<25
<25
1,172
<25
25.8
<25
694
669
15.2
17.9
707
17.2
10.5
28.6
Standard
Deviation
10.0
12.8
1.8
1.9
9.3
1.1
1.8
0.9
4.2
16.6
1.8
0.1
5.1
1.2
1.1
7.0
1.1
1.1
331
284
11.0
44.5
338
0.0
35.1
0.0
103
144
30.2
35.5
105
9.8
18.6
57.8
One-half of the detection limit used for non-detect samples for calculations.
Duplicate samples included in calculations
IN = at wellhead; BF = before filter; AF = after filter; PC = post-chlorination from clear well
Figure 4-20 shows a close up plot of the treated water results from samples taken after the filter (AF) and
after post-chlorination point from the clearwell (PC). The AF samples represent the filter effluent at the
time the sample was taken, while the PC samples represent the composite of the filter effluent in the
clearwell. Total arsenic levels in the treated water ranged from 6.3 to 14.3 |o,g/L and averaged 8.5 |o,g/L
after the filter. Total arsenic levels after post-chlorination ranged from 6.0 to 14.0 |o,g/L and averaged 8.4
Hg/L. There were four exceedances of arsenic above the 10 |o,g/L MCL during the study period, which
occurred on March 1, April 18, June 21, and June 28, 2005 (Table 4-13). Two of the four samples were
taken when Ap across Filter Cell No. 4 was elevated at 68.3 to 68.8 in of H2O. The data suggested that a
more frequent backwash schedule would be required in order to maintain the filter performance for
37
-------
Table 4-12. Summary of Other Water Quality Parameter Analytical Results
Parameter
Alkalinity
(as CaCO3)
Fluoride
Sulfate
Orthophosphate
(as PO4)
Silica
(as SiO2)
Nitrate (as N)
Turbidity
PH
Temperature
Dissolved Oxygen
ORP
Free Chlorine (as C12)
Total Chlorine (as C12)
Total Hardness
(as CaCO3)
Ca Hardness
(as CaCO3)
Mg Hardness
(as CaCO3)
Sampling
Location
IN
BF
AF
PC
IN
BF
AF
IN
BF
AF
IN
BF
AF
PC
IN
BF
AF
PC
IN
BF
AF
IN
BF
AF
PC
IN
BF
AF
PC
IN
BF
AF
PC
IN
BF
AF
IN
BF
AF
PC
PC
IN
BF
AF
PC
IN
BF
AF
PC
IN
BF
AF
PC
Unit
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
NTU
NTU
NTU
NTU
S.U.
S.U.
S.U.
S.U.
°C
°c
°c
°c
mg/L
mg/L
mg/L
mV
mV
mV
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
Sample
Count
31
31
31
24
7
7
7
7
7
7
29
29
29
25
31
31
31
24
7
7
7
31
31
31
24
29
29
29
29
29
29
29
29
21
21
21
28
28
28
28
28
7
7
7
6
7
7
7
6
7
7
7
6
Minimum
352
334
339
348
0.1
0.2
0.2
323
309
309
O.05
<0.05
0.05
O.05
29.0
24.9
28.8
28.6
O.04
O.04
0.04
3.5
3.1
O.I
0.1
7.2
7.2
6.4
7.4
9.3
9.9
10.6
10.5
1.3
4.3
4.3
-37
189
163
0.0
0.3
451
416
403
404
321
290
273
274
118
113
124
125
Maximum
714
682
691
413
0.2
0.6
0.4
385
352
367
O.06
O.06
0.06
O.06
34.2
33.3
33.2
33.1
O.05
0.06
0.15
23.0
14.0
7.1
16.0
7.6
7.5
7.5
7.9
11.2
12.1
12.2
12.3
4.1
6.4
6.4
-11
463
393
0.6
8.0
552
585
567
591
392
414
401
418
159
171
165
173
Average
402
390
388
379
0.2
0.3
0.3
353
336
338
O.05
O.05
0.05
O.05
31.2
30.5
30.5
31.1
O.05
0.05
0.05
15.7
5.2
0.6
1.6
7.3
7.4
7.4
7.5
10.0
10.7
11.1
11.5
2.6
5.4
5.4
-28
334
259
0.1
3.4
499
498
489
497
356
354
345
352
144
144
144
145
Standard
Deviation
63
59
61
19
0.1
0.1
0.1
22
16
23
0.0
0.0
0.0
0.0
1.0
1.8
0.9
0.9
0.00
0.02
0.05
3.8
1.9
1.3
3.9
0.1
0.1
0.2
0.1
0.4
0.4
0.4
0.4
0.8
0.7
0.7
6.3
75
64
0.1
1.4
39.9
67.8
62.3
71.6
27.8
48.7
48.2
52.8
14.4
20.5
15.1
20.8
One-half of the detection limit used for non-detect samples for calculations. Duplicate samples included in calculations.
Detections of orthophosphate removed due to detections in laboratory blank.
38
-------
04/03/05 05/03/05
Date
Figure 4-18. Total Arsenic Concentrations Across Treatment Train
arsenic removal. Further process modifications were required to allow for more frequent backwash at the
treatment plant as discussed in Section 4.3.5.
4.5.1.2 Iron Removal. Figure 4-21 shows the total iron levels across the treatment train over the
duration of the study period. Total iron levels in raw water ranged from 737 to 2,606 |o,g/L and averaged
1,344 |og/L. As shown in Table 4-11, iron in raw water existed primarily in the soluble form with an
average value of 1,172 |o,g/L. Given the average soluble iron and soluble arsenic levels in the source
water, this corresponded to an Fe:As ratio of 9: 1, which was below the target ratio for effective arsenic
removal of 20: 1. Supplemental iron addition was implemented at an average dose of 1.2 mg/L (as Fe)
using a FeCl3 solution. Including the 1 .2 mg/L of iron added to raw water, the average iron concentration
of 1,575 ng/L after the detention tank would represent about 38% of iron removed in the baffled detention
tank. This removal percentage was about two times higher than the 16.7 to 19.47% removal observed
under the baseline conditions on January 14, 2004. The use of dual polymers might have formed more
settleable and filterable particles during treatment. Total iron levels after the filters and after the post-
chlorination point ranged from <25 to 64 |o,g/L and <25 to 194 |og/L, respectively, suggesting leakage of
some iron particles through the filters. However, these iron levels were below the secondary MCL of
300
4.5.1.3 Manganese Removal. Total manganese levels in raw water ranged from 567 to 1,067 |o,g/L
with an average value of 694 |o,g/L (see Table 4-1 1 and Figure 4-22). Manganese in raw water existed
primarily in the soluble form at levels ranging from 598 to 868 |o,g/L and averaging 707 |o,g/L. After
prechlorination, KMnO4 addition, and the detention tank, soluble manganese concentrations decreased to
5.8 to 31.1 |o,g/L with an average value of 17.2 |o,g/L. An average of 98% of the soluble manganese in raw
water was converted to particulate manganese after the detention tank and before the filters. Total
manganese concentrations before the filter ranged from 452 to 1,03 1 |o,g/L, which was present primarily
as particulate manganese. Total and particulate manganese was effectively removed by the filters with its
concentration reduced to an average of 15.2 |o,g/L (with 10.5 |o,g/L as soluble manganese).
39
-------
Arsenic Species at Wellhead (IN)
120-
=
01/04/05 02/01/05 03/01/05 04/05/05 05/03/05 06/14/05
Date
QAs (participate)
• As (V)
D As (III)
07/12/05
160
Arsenic Species before Filter (BF)
40-
04/05/05
Date
Figure 4-19. Concentrations of Arsenic Species Across Treatment Train
40
-------
Arsenic Species after Filter (AF)
12
10 -
o
I «
4 -
2 -
01/04/05 02/01/05 03/01/05
04/05/05
Date
05/03/05 06/14/05 07/12/05
Arsenic Species after Post-Chlorination (PC)
12
10-
o
I «
2 -
n
01/04/05 02/01/05 03/01/05
n
n
04/05/05
Date
05/03/05 06/14/05 07/12/05
Figure 4-19. Concentrations of Arsenic Species across Treatment Train (Continued)
41
-------
After Filter
After Post-Chlorination
01/03/05 02/02/05 03/04/05 04/03/05 05/03/05 06/02/05 07/02/05 08/01/05
Date
Figure 4-20. Total Arsenic Concentrations in Treated Water
Table 4-13. Summary of Exceedances of 10 (ig/L during Performance Evaluation Study
Date
03/01/05
04/18/05(a)
06/21/05(b)
06/28/05
Total
Arsenic
Concentration
(uj/L)
10.3
10.6 [12.5]
14.3
11.4
Apat
Sampling
Event
(inofH2O)
20.6
68.3
68.8
45.1
Filter Run
Time at
Sampling
Event
(hr)
7.3
20.4
7.8
10.4
Throughput
at Sampling
Event
(gal)
123,954
346,392
132,444
176,592
Total Filter
Run
Time
(hr)
12.0
21.0
8.8
14.1
(a) Duplicate sample result in parentheses.
(b) On June 20, 2005, an incomplete backwash led to filter plugging after a run time of 8.8 hr.
The June 21, 2005, sample was taken prior to manual backwash of filters on June 21, 2005.
42
-------
3,000
2,500 -
—•—At Wellhead
-X-Before Filter
-*— After Filter
—•—After Post-Chlorination
£ 1,500
01/03/05 02/02/05
03/04/05
04/03/05 05/03/05
Date
06/02/05 07/02/05
08/01/05
Figure 4-21. Total Iron Concentrations Across Treatment Train
1,200
1,000 -
1
I
o
c
800 -
600 -
400 -
200 -
/
A ?
A /A /
/ \v"Y\*/
1 /\/ V
//
\
V \
^ V
-AtWellhead
-Before Filter
-After Filter
-After Post-Chlorination
-•-=•=
M
/ y\ A
\A
v
01/03/05 02/02/05
03/04/05
04/03/05 05/03/05
Date
06/02/05 07/02/05
08/01/05
Figure 4-22. Total Manganese Concentrations Across Treatment Train
43
-------
Approximately 77% to 100% of the total manganese was removed across the treatment train with an
average 98% removal rate. Among the 30 sampling events, three had total manganese levels above
50 |og/L in filter effluent including January 18, 2005, at 79.1 |o,g/L, March 22, 2005, at 64.2 |o,g/L, and
July 12, 2005, at 146 |o,g/L. On July 12, 2005, the sample was speciated: out of 146 |o,g/L total
manganese, 64% or 93.9 |o,g/L was present as particulate manganese. Soluble manganese after the filter
ranged from 1.1 to 10.7 |o,g/L with one outlier at 52.1 |o,g/L on July 12, 2005. Removal of soluble
manganese was observed across the MnO2-coated anthrasand filter ranging from 52% to 96% based on
the speciation results.
4.5.1.4 Other Water Quality Parameters. As shown in Table 4-12, DO levels were low in raw water
with an average value of 2.6 mg/L. As expected, DO levels increased significantly to an average value of
5.4 mg/L after aeration, rapid mixing, and detention. ORJ3 values also increased significantly after
chlorine addition, aeration, and potassium permanganate addition. The ORP values averaged -28 mV in
raw water, 334 mV after chemical addition and detention, and 259 mV after filtration. The post-
chlorination free chlorine levels averaged 0.1 mg/L (as C12) and the total chlorine levels averaged
3.4 mg/L (as C12). The average pH value of raw water was 7.3 and the average pH value of the treated
water was 7.4, so no significant change in pH occurred across the treatment train. Average alkalinity
values ranged from 379 to 402 mg/L (as CaCO3) across the treatment train. Average total hardness values
ranged from 489 to 499 mg/L (as CaCO3) across the treatment train (the total hardness is the sum of
calcium hardness and magnesium hardness). The water had predominantly calcium hardness. Fluoride
concentrations averaged 0.2 mg/L in raw water and were not affected by the MnO2-coated anthrasand
filtration. No significant levels of nitrate or orthophosphate were detected in raw water. Average sulfate
concentrations ranged from 336 to 353 mg/L across the treatment train. The silica (as SiO2) concentration
remained at approximately 30.5 to 31.2 mg/L across the treatment train.
Figure 4-23 shows the results of turbidity measurements of Filter Cell No. 4 effluent under three sets of
process conditions: 1) baseline conditions before process modifications in February 2004; 2) iron addition
(along with 0.12 mg/L of Aqua Hawk 9207 PWG addition that had been practiced at the plant as part of
the baseline conditions) in July 2004; and 3) supplemental iron (at 1.2 mg/L) and polymer (at 0.3 mg/L of
Aqua Hawk 9207 PWG and 0.5 mg/L of Aqua Hawk 127) additions in February 2005. The average
effluent turbidity was 0.032 NTU under the baseline conditions in February 2004 with little to no
particulate breakthrough from the filter. With the addition of about 1.1 mg/L (as Fe) in July 2004,
effluent turbidity readings increased significantly to 0.015 to 3.58 NTU (averaged 0.31 NTU), which
represented one to two orders of magnitude increase over the baseline readings. The data confirmed
incomplete filtration of particles and, along with the analytical results, further supported the need for
supplemental polymer addition to improve particle filterability by the filter. After second polymer
addition, the removal of particles improved significantly with an average effluent turbidity reading of
0.021 NTU in February 2005, comparable to the baseline value of 0.032 NTU in February 2004.
The effluent turbidity readings averaged 0.030 NTU over the entire study period from January 2005 to
July 2005, suggesting effective particulate removal throughout the duration of all filter runs. However,
the use of the supplemental polymer did result in an increased rate of Ap buildup and filter backwash as
discussed in Section 4.4.1.1.
4.5.2 Backwash Water Sampling. Table 4-14 summarizes the analytical results from five
backwash water sampling events, which took place prior to the October 21, 2005, modification of the
backwash water sampling procedure for inclusion of total suspended solids (TSS) and total metals. The
backwash water samples were analyzed for pH, turbidity, TDS, and soluble As, Fe, and Mn from grab
samples taken during the backwash of two out of the four filter cells. Soluble arsenic concentrations in
the backwash water ranged from 7.5 to 11.9 jog/L and averaged 9.8 |og/L.
44
-------
Backwashes occured on Mondays, Wednesdays, and Fridays
2/15/05
Date
Figure 4-23. Turbidity Readings from Filter Cell No. 4 Effluent in February 2004 (Baseline),
July 2004 (Iron Addition), and February 2005 (Supplemental Iron and Polymer Additions)
45
-------
Table 4-15 presents the results of total metals analysis for two backwash water solid samples (with three
replicates for each sample) collected on October 6, 2005. The iron levels in the solids ranged from
1.99E+05 to 3.07E+05 ng/g and the arsenic levels from 7.63E+03 to 1.15E+04 ng/g. This yields an
Fe:As ratio of 26:1, which is slightly higher than the 20:1 ratio for effective arsenic removal (EPA, 2001;
Sorg, 2002). These data suggest that natural iron solids may have a greater As(V) adsorptive capacity
than iron solids formed from supplemental iron addition.
Table 4-16 shows the TCLP results of the backwash water solids. The samples were filtered through
0.7 jam glass fiber filters. The solid-liquid compositions were 13.8% solid and 86.2% liquid for Sample
BW1 and 16.2% solid and 83.8% liquid for Sample BW2. The filtrates were preserved with HNO3 until
they could be digested for metal analyses. Both samples were found to require Extraction Fluid No. 1
(EF1), which contains 5.7 mL of acetic acid and 64.3 mL of NaOH with a pH of 4.93. Two 10 gram solid
portions of each sample were extracted with EF1 on a rotary agitation device for 18 hr. The solids were
filtered off and discarded. The extracts were digested along with the initial filtrates for metal analyses
according to EPA Methods 200.7 for As, Ba, Cd, Cr, Pb, Se, and Ag and 245.1 for Hg. The results for
each sample were obtained by adding the filtrate and extract results based on their percentage of the
sample. The TCLP results of the backwash solids showed below the detection level of arsenic in the
leachate at <0.5 mg/L. Barium was in the leachate at 0.068 to 0.070 mg/L. Chromium was in the
leachate at 0.052 to 0.055 mg/L. The TCLP regulatory limit set by EPA is 5 mg/L for arsenic, 100 mg/L
for barium, and 5 mg/L for chromium. Therefore, the backwash solids can be disposed of in a landfill.
4.5.3 Distribution System Water Sampling. The results of the distribution system sampling are
summarized in Table 4-17. The duration of the stagnation time before the sampling ranged from 6 to 14
hr and averaged 8 hr. The baseline sample DS3 collected on December 1, 2003, had an extended
stagnation time of 264 hr. Therefore, the results from this sample are not included in the discussion
below.
There was no major change in pH values, which ranged from 7.3 to 7.7 before and 7.4 to 8.2 after the
process modifications. Alkalinity levels ranged from 353 to 403 and from 333 to 401 mg/L (as CaCO3)
before and after process modifications, respectively.
Arsenic concentrations in samples collected before the process modifications ranged from 26.6 to
59.1 ng/L and averaged 39.0 |o,g/L. After the process modifications, arsenic concentrations decreased
significantly to 6.0 to 18.8 |o,g/L (averaged 12.1 |o,g/L) in the samples collected from Events 1 to 7. These
concentrations were higher than those in treated water (i.e. 6.3 to 14.3 |o,g/L and averaged 8.5 |o,g/L) as
shown in Table 4-11. The higher levels of arsenic in the distribution system may be due to: 1) longer
filter runs over the weekends with durations ranging from 18.5 to 20.3 hr might have contributed to
elevated levels of particulate arsenic in the treated water sent to the distribution system, and/or 2)
solubilization, destablization, and/or desorption of arsenic-laden particles/scales might have occurred in
the distribution system (Lytle, 2005). More frequent backwashing as described in Section 4.4.1.2 should
help to eliminate the longer filter runs over the weekend.
Iron concentrations in the baseline samples ranged from <25 to 41 |og/L. Since the process modifications,
iron levels in the distribution system remained at <25 |o,g/L. Manganese levels in the distribution system
samples averaged 12.3 |o,g/L in the baseline samples and decreased to an average of 6.7 |o,g/L after the
process modifications. In general, total managanese levels in the distribution samples were lower than
those in the treated water from the post-chlorination point (averaged 17.9 |og/L). Manganese in the
treated water was present primarily in the soluble form. The lower levels in the distribution system may
be due to further oxidation of Mn(II) after post-chlorination and adsorption and/or coating onto metal
oxide scales in the distribution system.
46
-------
Table 4-14. Backwash Water Sampling Results
Sampling
Event
No.
1
2
3
4
5
Date
03/23/05
04/18/05
05/25/05
06/21/05
07/25/05
BW1
Vessel No. 1
W
o.
s.u.
7.6
7.6
7.2
7.4
7.4
Turbidity
NTU
160
130
110
160
200
<»
mg/L
1,050
1,020
928
986
1,010
As (Soluble)
ug/L
7.5
11.8
8.5
11.9
10.2
Fe (Soluble)
ug/L
<25
<25
<25
<25
<25
£
Mg/L
46.6
8.2
8.9
2.6
2.4
BW2
Vessel No. 2
W
o.
S.U.
7.5
7.6
7.3
7.4
7.4
Turbidity
NTU
31
150
120
200
160
VI
mg/L
1,130
1,540
946
976
984
"o
ug/L
7.7
10.6
7.6
11.4
10.5
Fe (Soluble)
ug/L
<25
<25
<25
<25
<25
!
Ug/L
37.2
20.1
0.8
1.8
0.8
TDS = total dissolved solids
Table 4-15. Backwash Solid Sample Total Metal Results
Metals
Units
Al
As
Ca
Cd
Cu
Fe
Mg
Mn
P
Pb
Ni
Si
Zn
BW1-
Solids A
(Mg/g)
3.05E+03
1.15E+04
5.49E+04
2.80E-01
2.26E+01
3.07E+05
5.51E+03
1.25E+05
3.50E+03
3.19E+00
9.53E+00
2.14E+02
1.78E+02
BW1-
Solids B
(Mg/g)
2.56E+03
7.65E+03
3.98E+04
2.30E-01
1.83E+01
2.00E+05
4.55E+03
8.02E+04
2.99E+03
2.70E+00
7.78E+00
1.02E+02
1.38E+02
BW1-
Solids C
(ng/g)
3.24E+03
9.10E+03
5.05E+04
3.10E-01
2.36E+01
2.38E+05
5.82E+03
9.97E+04
3.61E+03
3.52E+00
9.53E+00
5.84E+02
1.71E+02
Average
(Mg/g)
2.95E+03
9.42E+03
4.84E+04
2.70E-01
2.15E+01
2.49E+05
5.29E-K)3
1.02E-H)5
3.37E+03
3.14E+00
8.95E+00
3.00E-H)2
1.62E+02
BW2-
Solids A
(Mg/g)
2.82E+03
8.02E+03
4.32E+04
2.20E-01
1.97E+01
2.06E+05
5.16E+03
8.55E+04
3.18E+03
2.94E+00
8.74E+00
1.49E+02
1.49E+02
BW2-
Solids B
(ng/g)
2.50E+03
7.63E+03
3.95E+04
2.10E-01
1.84E+01
1.99E+05
4.61E+03
8.72E+04
2.89E+03
2.81E+00
7.66E+00
1.21E+02
1.35E+02
BW2-
Solids C
(ng/g)
2.99E+03
1.05E+04
4.62E+04
2.40E-01
2.14E+01
2.73E+05
5.48E+03
1.14E+05
3.26E+03
3.19E+00
9.36E+00
1.47E+02
1.57E+02
Average
(Mg/g)
2.77E-KJ3
8.73E-KJ3
4.29E+04
2.20E-01
1.98E+01
2.26E-KJ5
5.08E-K)3
9.55E+04
3.11E+03
2.98E+00
8.59E-K)0
1.39E-K)2
1.47E+02
Table 4-16. Backwash Solids Sample TCLP Results
Parameter
As
Ba
Cd
Cr
Pb
Ag
Se
Hg
Unit
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
BW1-10/06/05
<0.5
0.068
<0.05
0.055
<0.1
O.05
<0.3
<0.003
BW2-10/06/05
<0.5
0.070
O.05
0.052
<0.1
<0.05
0.3
O.003
47
-------
Table 4-17. Distribution Sampling Results
=
§
—
ex
•S
oi
cc
BL1
BL2
BL3
BL4
1
2
3
4
5
6
7
ex
i
s «
§ S
ce Q
12/02/03(b)
12/17/03
01/06/04
01/22/04
01/18/05
02/22/05
03/22/05
04/06/05
05/03/05
06/14/05
07/12/05
DSl
,£,
^
QJ
g
H
1
cc
7.0
7.0
7.0
7.0
7.8
7.5
NS
7.0
7.0
7.5
7.0
-
r&
IT]
e.
7.6
7.4
7.5
7.5
7.5
7.8
NS
7.7
7.4
7.5
7.4
0
o
o
a
"M
g
1
•3
^
353
377
387
379
338
392
NS
397
382
374
352
1
1/3
<
32.5
33.4
40.7
47.3
13.9
15.1
NS
18.8
13.9
17.8
18.1
"ex
A
<25
<25
<25
<25
<25
<25
NS
<25
<25
<25
<25
--
A,
§
11.8
6.1
3.6
3.1
2.9
0.8
NS
8.0
1.0
1.0
5.3
A
^
—
2.1
2.0
3.3
4.1
2.9
2.4
NS
4.4
2.7
2.5
0.8
A
9
O
104
89.3
111
126
161
243
NS
352
251
241
107
DS2
,jv
^
QJ
g
H
B
1
cc
7.0
6.7
14.0
8.0
10.0
10.8
9.0
8.8
9.5
6.0
10.8
-
IT]
e.
7.3
7.7
7.7
7.5
7.5
7.4
7.4
7.8
7.4
7.4
7.4
0
o
o
a
"M
g
1
•3
^
370
371
393
399
351
400
355
388
395
392
352
/— \
3.
1/3
^
35.2
32.4
41.9
46.3
11.5
9.8
11.2
14.8
10.6
12.7
13.4
A
26
<25
<25
<25
<25
<25
<25
<25
<25
<25
<25
-
"ex
fi
§
47.1
5.6
9.4
1.4
4.4
1.9
36.3
16.6
1.1
5.8
6.9
A
^
—
56.8
2.0
8.2
2.0
1.7
1.0
3.1
2.5
1.2
1.0
0.2
~ex
A
9
O
198
76.2
142
102
68.4
63.2
93.0
115
78.8
54.2
13.9
DS3(a)
,jv
^
QJ
g
H
9
J
1
CO
264(c)
8.5
7.3
7.5
7.0
7.0
7.0
7.5
7.5
8.5
7.9
-
K
e.
8.1
7.6
7.7
7.8
7.5
7.8
7.4
7.8
7.7
8.2
7.7
0
0
O
S
"ex
g
=
g
^
404
371
379
403
359
382
333
401
377
387
352
/— \
~5x
3.
1/3
^
41.5
26.6
33.5
59.1
6.7
9.9
6.0
7.5
8.8
9.8
12.3
A
31
<25
<25
41
<25
<25
<25
<25
<25
<25
<25
-
"ex
fi
§
33.9
6.2
1.2
39.4
17.2
1.9
5.9
6.6
2.0
4.9
3.2
A
^
—
4.4
3.2
1.8
4.3
5.9
5.1
12.5
2.9
5.0
1.7
2.9
~ex
A
9
O
384
367
333
287
121
279
574
132
263
125
307
(a) Water softener present at this location.
(b) Sample DS3 collected on December 1, 2003.
(c) Stagnation time high due to sample tap not being used over an extended period of time.
NA = not analyzed; BL = baseline sampling
Lead action level =15 ug/L; copper action level =1.3 mg/L
ug/L as units for all analytical parameters except for pH (S.U.) and alkalinity (mg/L [as CaCO3]).
-------
Lead levels in the distribution system during the baseline sampling events ranged from 1.8 to 8.2 |o,g/L
with one outlier at 56.8 |o,g/L exceeding the action level of 15 |o,g/L for lead. After the process
modifications, lead levels ranged from 0.2 to 12.5 |o,g/L with an average value of 3.1 |og/L. Lead levels in
the distribution system did not appear to have been significantly affected by the process modifications.
The copper concentrations in the distribution system averaged 178 |o,g/L before and 182 |o,g/L after
process modifications. The process modifications did not appear to have an impact on copper levels in
the distribution system and no samples exceeded the 1,300 |o,g/L action level for copper.
4.6
System Cost
The cost of the system was evaluated based on the capital cost per gpm (or gpd) of design capacity and
the O&M cost per 1,000 gal of water treated. This included the tracking of capital cost for equipment,
engineering, and installation and O&M cost for chemical supply, electrical power consumption, and
labor. However, the cost associated with the building, sanitary sewer connections, and other discharge-
related infrastructure was not included in the treatment system cost, because it was not included in the
scope of the demonstration project, and was funded previously by the demonstration site.
4.6.1 Capital Cost. The capital investment for the process modifications at Lidgerwood, North
Dakota, was $57,038 (Table 4-18), which included $32,452 for equipment, $5,786 for engineering, and
$18,800 for installation. The capital equipment cost also included freight and sales tax.
Table 4-18. Summary of Capital Cost for the Lidgerwood, ND Process Modifications
Description
Quantity
Cost
% of Capital
Investment Cost
Equipment Cost
Chemical Feed System
Turbidimeter
dP Transmitter
Data Logger
Drum Scale
Other Miscellaneous
Reclaim Pump
Polymer Tank Mixer
Labor
Warranty
Equipment Total
1
4
1
1
1
-
-
-
-
$5,570
$9,567
$1,894
$3,703
$3,940
$1,177
$844
$454
$2,020
$3,283
$32,452
-
-
-
-
-
-
-
-
57%
Engineering Cost
Engineering Total
-
$5,786
10%
Installation Cost
Material
Labor
Travel
Installation Total
Total Capital Investment
-
-
-
-
-
$1,493
$12,307
$5,000
$18,800
$57,038
-
-
-
33%
100%
The equipment cost was $32,452, or 57% of the total capital investment. The primary equipment for the
iron addition system included a 60-gal chemical day tank with secondary containment, a tank mixer, a
chemical metering pump, associated materials such as tubing and fasteners, and warranty. In addition,
49
-------
on-line instrumentation including a Scaletron low-profile drum scale, four Hach 1720D low-range
turbidimeters, a Foxboro differential pressure cell, and a Telog data logging system, was installed at the
plant to track filter cell performance both before and after process modifications. The system warranty
included repair and/or replacement of any equipment or installation workmanship for a period of 12
months after system start-up. The equipment cost also includes the cost of a second polymer mixer and a
new reclaim pump. It does not include the cost of the second polymer feed system since an existing spare
chemical feed pump and tank were used.
The engineering cost ($5,786, or 10% of the total capital cost) included the costs for labor for the
preparation of a process design report and engineering plans including a P&ID, general assembly
drawing, turbidity meter interconnect, and electrical schematics.
The installation cost included the costs for equipment and labor to ship, install, and shakedown the FeCl3
addition system. The primary installation activities included placing the ferric chloride tank on the drum
scale and spill containment deck, mounting the tank mixer and pump to a wall bracket, and connecting the
tubing from the chemical metering pump to the injection point at the rapid mix tank. The installation also
included labor for all electrical connections, as well as connection and calibration of the associated
instrumentation including the drum scale, turbidimeters, and differential pressure cell. The installation
cost was $18,800, or 33% of the total capital cost.
The total capital cost of $57,038 was normalized to the system's rated capacity of 250 gem (360,000 gpd),
which resulted in $228 per gpm ($0.16 per gpd). The total capital cost of $57,038 was converted to an
annualized cost of $5,384/year using a capital recovery factor of 0.09439 based on a 7%
interest rate and a 20-year return. Assuming that the system was operated 24 hours a day, seven days a
week at the design flowrate of 250 gpm to produce 131.4 million gal of water per year, the unit capital
cost would be $0.04/1,000 gal. However, the system was operated an average of 6.1 hr/day and produced
22.1 million gal of water during the seven-month study period. The corresponding annual production
would be approximately 38.2 million gal of water. The unit capital cost was increased to $0.14/1,000 gal
at this reduced rate of production.
4.6.2 Operation and Maintenance Cost. The incremental O&M cost for the process
modifications included primarily costs associated with additional chemical supply for FeCl3 and Aqua
Hawk 127 polymer. The incremental O&M cost from the process modifications was $0.04/1,000 gal as
summarized in Table 4-19. The treatment plant was pre-existing and the process modifications did not
contribute significantly to the operator's labor hours and/or the electrical demand for the entire treatment
plant. The total O&M cost also was estimated to include all chemical supply costs (e.g. NaOCl, KMnO4,
Aqua Hawk 9207 PWG polymer, Aqua Hawk 127 polymer, and fluoride), electrical usage, and labor.
The total O&M was estimated at $0.52/1000 gal of treated water.
50
-------
Table 4-19. O&M Cost for the Lidgerwood, ND Treatment System
Cost Category
Volume Processed (kgal)
Value
22,012
Assumptions
From 01/01/05 to 07/31/05
Incremental Chemical Usage for Process Modifications
FeCl3 Unit Price ($/lb)
FeCl3 Consumption Rate (lb/1,000 gal)
FeCl3 ($/l,000 gal)
Aqua Hawk 127 Unit Price ($/gal)
Aqua Hawk 127 Consumption Rate (gal/1,000 gal)
Aqua Hawk 127 ($71,000 gal)
Total Incremental Chemical Cost/1,000 gal
$0.40
0.08
$0.03
$25.93
5xlO'4
$0.01
$0.04
35% FeCl3 in a 600 Ib drum;
fuel surcharge included.
—
—
Includes fuel surcharge and
container recycle charge
—
—
—
Chemical Usage for Pre-Existing Chemical Feed Systems
Aqua Hawk 9207 PWG Unit Price ($/lb)
Aqua Hawk 9207 PWG Consumption Rate (lb/1,000 gal)
Aqua Hawk 9207 PWG Chemical cost ($/l,000 gal)
Potassium Permanganate Unit Price ($/lb)
Potassium Permanganate Consumption Rate (lb/1,000 gall)
Potassium Permanganate Chemical cost ($/l,000 gal)
Chlorine Unit Price ($/lb)
Chlorine Consumption Rate (lb/1,000 gal)
Chlorine Chemical cost ($/l,000 gal)
Fluoride Unit Price ($/gal)
Fluoride Consumption Rate (lb/1,000 gal)
Fluoride Chemical cost ($/l,000 gal)
Total Pre-Existing Chemical Cost/1,000 gal
$4.37
0.003
$0.01
$3.36
0.010
$0.03
$1.63
0.041
$0.07
$9.11
0.005
$0.04
$0.15
—
—
—
—
—
—
—
—
—
—
—
—
Electricity
Power use ($/l, 000 gal)
$0.03
—
Labor
Average weekly labor (hr)
Labor cost ($/l,000 gal)
Total O&M Cost/1,000 gal
10.7
$0.29
$0.52
Labor rate = $20/hr
—
51
-------
Section 5.0: REFERENCES
Battelle. 2003. Revised Quality Assurance Project Plan for Evaluation of Arsenic Removal Technology.
Prepared under Contract No. 68-C-00-185, Task Order No. 0019, for U.S. Environmental
Protection Agency, National Risk Management Research Laboratory, Cincinnati, OH.
Battelle. 2004. Final System Performance Evaluation Study Plan: U.S. EPA Demonstration of Arsenic
Removal Technology at Lidgerwood, ND. Prepared under Contract No. 68-C-00-185, Task Order
No. 0019 for U.S. Environmental Protection Agency, National Risk Management Research
Laboratory, Cincinnati, OH.
Chen, AS.C., L. Wang, J. Oxenham, and W. Condit. 2004. Capital Costs of Arsenic Removal
Technologies: U.S. EPA Arsenic Removal Technology Demonstration Program Round 1.
EPA/600/R-04/201. U.S. Environmental Protection Agency, National Risk Management
Research Laboratory, Cincinnati, OH.
Edwards, M., S. Patel, L. McNeill, H. Chen, M. Frey, A.D. Eaton, R.C. Antweiler, and H.E. Taylor. 1998.
"Considerations in As Analysis and Speciation." J. AWWA 90(3): 103-113.
EPA. 2003. Minor Clarification of the National Primary Drinking Water Regulation for Arsenic.
Federal Register, 40 CFR Part 141.
EPA. 2002. Lead and Copper Monitoring and Reporting Guidance for Public Water Systems.
EPA/816/R-02/009. U.S. Environmental Protection Agency, Office of Water, Washington, D.C.
EPA. 2001. National Primary Drinking Water Regulations: Arsenic and Clarifications to Compliance
and New Source Contaminants Monitoring. Federal Register, 40 CFR Parts 9, 141, and 142.
Great Lakes-Upper Mississippi River Board of State Sanitary Engineers. 2003. Recommended Standards
for Water Works. Health Education Services. Albany, New York.
Lytle, D. 2005. Coagulation/Filtration: Iron Removal Processes Full-Scale Experience. U.S.
Environmental Protection Agency Workshop on Arsenic Removal from Drinking Water,
Cincinnati, Ohio.
Sorg, T.J. 2002. "Iron Treatment for Arsenic Removal Neglected." Opflow, AWWA, 28(11): 15.
Wang, L., W. Condit, and A.S.C. Chen. 2004. Technology Selection and System Design: U.S. EPA
Arsenic Removal Technology Demonstration Program Round 1. EPA/600/R-05/001. U.S.
Environmental Protection Agency, National Risk Management Research Laboratory, Cincinnati,
OH.
52
-------
APPENDIX A
OPERATIONAL DATA
-------
Table A-l. Daily System Operation Log for Lidgerwood, ND (Page 1 of 5)
Date
01/01/05
01/02/05
01/03/05
01/04/05
01/05/05
01/06/05
01/07/05
01/08/05
01/09/05
01/10/05
01/11/05
01/12/05
01/13/05
01/14/05
01/15/05
01/16/05
01/17/05
01/18/05
01/19/05
01/20/05
01/21/05
01/22/05
01/23/05
01/24/05
01/25/05
01/26/05
01/27/05
01/28/05
01/29/05
01/30/05
01/31/05
02/01/05
02/02/05
02/03/05
02/04/05
02/05/05
02/06/05
02/07/05
02/08/05
02/09/05
02/10/05
02/11/05
02/12/05
02/13/05
02/14/05
02/15/05
02/16/05
02/17/05
02/1 8/05
02/19/05
02/20/05
02/21/05
02/22/05
Daily
Plant
Hours
(hrs)
NA
5.6
5.4
5.2
6.3
5.3
6.7
5.1
4.7
6.7
5
6.4
5.6
5.4
5.8
6.2
5.7
5.2
6.5
5.7
7
6.2
7.4
5.9
5 5
5.6
5.6
7.2
5.6
6.9
6.5
4.5
6.5
5.7
6.8
5.6
6
6.5
5.7
7
6.3
6.8
6.9
4.9
7.6
4.5
6.6
4.5
6.6
4.7
7.4
4.9
5.9
Well #1
(hrs)
NA
NA
NA
5.2
6.4
5.3
6.7
5
4.9
6.7
5
6.4
NA
NA
6.5
6.2
5.8
5.2
6.5
5.7
7
6.3
7.4
5.9
5.6
5.6
5.7
7
5.8
6.9
6.5
4.5
1.0
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
Well #3
(hrs)
NA
5.7
5.4
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
5.6
5.7
6.8
5.7
6
6.5
5.8
6.9
6.5
6.7
7
4.9
7.6
4.5
6.7
4.5
6.6
4.4
7.5
5
6.1
Backwash
Pump #1
(hrs)
NA
0
0
0
0.5
0
0
0
0
0.8
0
0
0
0.8
0
0
0
0
0.7
0.1
0
0
0
0.8
0
0
0
0.7
0
0
0
0
0.7
0
0
0
0
0.8
0
0
0
0.8
0
0
0
0
0.7
0
0
0
0
0.8
0
Backwash
Pump #2
(hrs)
NA
0
0.8
0
0
0
0.7
0
0
0
0
0.8
0
0
0
0
0.8
0
0
0
0.9
0
0
0
0
0.8
0
0
0
0
0.7
0
0
0
0.8
0
0
0
0
0.8
0
NA
0
0
0.7
0
0
0
0.8
0
0
0
0
Reclaim
Pump
(hrs)
NA
3
0.3
5.2
3 2
5.4
1.4
5
3.8
0.3
5
3.4
5.7
3.1
5.9
3
0.5
5.2
3.1
5.7
3.1
6.3
2.9
0
5.5
3.3
5.7
3.3
5.8
3.2
0.3
4.5
4.4
5.7
3.4
5.6
NA
NA
5.8
3.5
6.4
2.4
7
2 2
0.4
4.5
4.4
4.5
4.4
2
NA
NA
5.7
Raw Water
(gal)
98721600
98814200
98902300
98987000
99092700
99181200
99291700
99376000
99456700
99569100
99650500
99757700
99852000
99942200
39600
144400
239500
326700
435400
530800
647400
752400
875100
974400
1066000
116000
1255100
1372100
1468600
1584900
1694600
1770500
1 876700
1969400
2081400
2173400
2272500
2378900
2473300
2587700
2693500
2804000
2916300
2997900
3120800
3194300
3303600
3377700
3486100
3563200
3684000
3765600
3861900
(gpm)
NA
270.8
271.9
271.5
275.3
278.3
274.9
281.0
274.5
279.6
271.3
279.2
NA
NA
249.7
281.7
273.3
279.5
278.7
278.9
277.6
277.8
276.4
280.5
272.6
NA
NA
278.6
277.3
280.9
281.3
281.1
268.2
271.1
274.5
269.0
275.3
272.8
271.3
276.3
271.3
274.9
267.4
277.6
269.5
272.2
271.9
274.4
273.7
292.0
268.4
272.0
263.1
Reclaim Water
(gal)
6806100
6810790
6811190
6819390
6824490
6832910
6835050
6843100
6848840
6849470
6857330
6862640
6871670
6876650
6885830
6890510
6891320
6899640
6904330
6913420
6918110
6928160
6932670
6932670
6941450
6946590
6955600
6960700
6970030
6974770
6975350
6982620
6989320
6998420
7003700
7012660
7017570
7017570
7026760
7032210
7042460
7046110
7057100
7060620
7061170
7068390
7075190
7082430
7089210
7096760
7103280
7103280
7112690
(gpm)
NA
26.1
22 2
26.3
26.6
26.0
25.5
26.8
25.2
35.0
26.2
26.0
26.4
26.8
25.9
26.0
27.0
26.7
25.2
26.6
25.2
26.6
25.9
NA
26.6
26.0
26.3
25.8
26.8
24.7
32.2
26.9
25.4
26.6
25.9
26.7
NA
NA
26.4
26.0
26.7
25.3
26.2
26.7
22.9
26.7
25.8
26.8
25.7
62.9
NA
NA
27.5
Treated
Water
(kgal)
290730
290815
290882
290959
291046
291133
291217
291305
291376
291468
291541
291626
291718
291793
291888
291984
292053
292138
292218
292310
292407
292505
292617
292689
292778
292852
292943
293036
293136
293243
293317
293396
293476
293567
293656
293745
293843
293918
294006
294098
294206
294293
294396
294478
294565
294637
294725
294796
294885
294965
295072
295132
295221
FeCl3
(mg/L)
.41
.54
.42
.33
.37
.38
.24
.33
.48
.46
.14
.24
.18
.26
.36
.37
.30
.21
.26
.19
.12
.12
.34
.25
.12
.18
.15
.14
22
.15
.13
.17
.24
.25
.18
.13
.11
.21
.15
.30
.34
.17
.34
.43
.45
.52
.27
.14
.15
.04
.13
.21
.35
Aqua Hawk
9207 PWG
(mg/L)
0.29
0.31
0.15
0.29
0.29
0.28
0.28
0.29
0.27
0.31
0.28
0.29
0.31
0.30
0.24
0.28
0.26
0.27
0.27
0.26
0.20
0.22
0.25
0.25
0.23
0.25
0.29
0.24
0.27
0.25
0.27
0.26
0.23
0.26
0.24
0.27
0.23
0.25
0.24
0.25
0.28
0.26
0.22
0.26
0.24
0.26
0.26
0.23
0.26
0.27
0.25
0.26
0.25
Aqua Hawk
127 (mg/L)
0.51
0.52
0.49
0.49
0.45
0.51
0.52
0.50
0.48
0.51
0.47
0.64
0.51
0.52
0.54
0.46
0.52
0.51
0.52
0.50
0.48
0.50
0.48
0.49
0.53
0.47
0.46
0.46
0.50
0.45
0.46
0.55
0.47
0.48
0.45
0.50
0.48
0.46
0.47
0.46
0.50
0.50
0.56
0.50
0.48
0.51
0.46
0.48
0.46
0.53
0.50
0.52
0.49
-------
Table A-l. Daily System Operation Log for Lidgerwood, ND (Continued) (Page 2 of 5)
Date
02/23/05
02/24/05
02/25/05
02/26/05
02/27/05
02/28/05
03/01/05
03/02/05
03/03/05
03/04/05
03/05/05
03/06/05
03/07/05
03/08/05
03/09/05
03/10/05
03/1 1/05
03/12/05
03/13/05
03/14/05
03/15/05
03/16/05
03/17/05
03/1 8/05
03/19/05
03/20/05
03/21/05
03/22/05
03/23/05
03/24/05
03/25/05
03/26/05
03/27/05
03/28/05
03/29/05
03/30/05
03/31/05
04/01/05
04/02/05
04/03/05
04/04/05
04/05/05
04/06/05
04/07/05
04/08/05
04/09/05
04/10/05
04/1 1/05
04/12/05
04/13/05
04/14/05
04/15/05
04/16/05
Daily Plant
Hours
(hrs)
5.7
7.3
3.9
5.5
6.2
7.4
5.8
5.6
5.1
5.8
5.7
6.5
6.1
4.8
6.3
5.4
4.5
6.8
5.9
6.2
5.9
5.6
5.9
5.7
6.1
6.4
6.1
5.7
6
7
6.8
6
5.3
6.1
5.6
6.8
5.7
7.2
5
5.3
5.4
7.5
3.9
6.3
8.3
6.6
5.5
6.8
9.7
7
5.8
7
5.6
Well #1
(hrs)
NA
NA
NA
NA
NA
NA
NA
5.4
5.3
5.8
5.7
6.5
6.1
4.8
6.3
5.5
4.6
6.7
6.0
6.2
5.9
5.7
5.9
5.7
6.1
6.5
6.1
5.8
6.0
6.9
7.0
5.9
5.4
6.1
5.6
6.8
5.8
7.2
NA
NA
NA
NA
9.2
6.5
11.6
11.0
11.1
12.2
7.9
1.8
NA
NA
NA
Well #3
(hrs)
5.9
7.2
3.9
5.5
6.3
7.4
5.9
0.1
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
5
5.4
5.4
7.6
2.7
6.3
6.9
6.1
6.5
6.4
9.5
7
5.8
7
5.7
Backwash
Pump #1
(hrs)
0
0
0.6
0
0
0
0
0.7
0
0
0
0
0.8
0
0
0
0
0.8
0
0
0
0.7
0
0
0
0
0.8
0
0
0
0.7
0
0
0.1
0
0.8
0
0
0
0
0.8
0
0
0
0.7
0
0
0
0
0.6
0
0
0
Backwash
Pump #2
(hrs)
0.8
0
0
0
0
0.7
0.1
0
0
0.7
0
0
0
0
0.8
0
0
0
0
NA
NA
0
0
0.6
0
0
0
0
0
0.8
0
0
0
0.5
0
0
0
0.7
0
0
0
0
0
0.9
0
0
0
0.8
0
0
0
0.7
0
Reclaim
Pump
(hrs)
3.5
7.2
1.9
5.5
1.4
0
5.8
3.4
5.4
3.4
5.7
6.5
NA
NA
4.9
5.4
4
3.7
5.4
NA
NA
2.8
5.2
3.4
6
1.1
0
5.8
3.4
4.6
4.4
6
2.9
0
4.2
0
5.8
0.5
5
5.4
3.5
6.2
2.6
4.5
2 2
6.5
5.6
2.5
6.6
NA
NA
NA
NA
Raw Water
(gal)
3958500
4076800
4141100
4231800
4334700
4458100
4554000
4646000
4734300
4830200
4925200
5034000
5136500
5217900
5223400
5414300
5491900
5608100
5705900
5810200
5910500
6005400
6104700
6202900
6303600
6413100
6515400
6613200
6715100
6831700
6948300
7049400
7139200
7242600
7337200
7451800
7546900
7671000
7754800
7843600
7933900
8057900
8105500
8212800
8329400
8434300
8546000
8653600
8816200
8936700
9036000
9156600
9252300
(gpm)
272.9
273.8
274.8
274.8
272.2
ins
270.9
284.0
277.7
275.6
277.8
279.0
280.1
282.6
14.6
578.5
281.2
289.1
271.7
280.4
283.3
277.5
280.5
287.1
275.1
280.8
279.5
281.0
283.1
281.6
277.6
285.6
277.2
282.5
281.5
280.9
273.3
287.3
279.3
274.1
278.7
271.9
293.8
283.9
281.6
286.6
286.4
280.2
285.3
286.9
285.3
287.1
279.8
Reclaim Water
(gal)
7118120
7129590
7132410
7141060
7143260
7143260
7152520
7157680
7166120
7171640
7180800
7191140
7196480
7204260
7211850
7220550
7226760
7232570
7240990
7240990
7250470
7255130
7264230
7269820
7279130
7280840
7280840
7290100
7295340
7302650
7309550
7319020
7323490
7323490
7330090
7330090
7339100
7339810
7347850
7356090
7361440
7371350
7375290
7382470
7385760
7396090
7404930
7408720
7422700
7422700
7431500
7431500
7439940
(gpm)
25.9
26.6
24.7
26.2
26.2
NA
26.6
25.3
26.0
27.1
26.8
26.5
NA
NA
25.8
26.9
25.9
26.2
26.0
NA
NA
Tin
29.2
27.4
25.9
25.9
NA
26.6
25.7
26.5
26.1
26.3
25.7
NA
26.2
NA
25.9
23.7
26.8
25.4
25.5
26.6
25.3
26.6
24.9
26.5
26.3
25.3
35.3
NA
NA
NA
NA
Treated
Water
(kgal)
295301
295416
295462
295549
295640
295732
295826
295895
295984
296055
296141
296236
296309
296392
296470
296558
296638
296723
296817
296893
296989
297062
297157
297242
297337
297430
297504
297598
297692
297785
297879
297982
298059
298141
298226
298311
298409
298491
298569
298648
298728
298827
298881
298960
299050
299153
299253
299332
299496
299579
299674
299772
299856
FeCl3
(mg/L)
.08
.11
.13
.16
.23
.23
.20
.17
.27
.15
.18
.19
.11
.24
.21
.25
.31
22
.31
.27
.26
.23
.21
.28
.18
.21
.15
.16
.13
.09
.23
.36
.35
.30
22
.11
.18
.18
.21
.27
.24
.19
.25
.27
.31
.25
.20
.20
.16
.12
.12
.08
.07
Aqua Hawk
9207 PWG
(mg/L)
0.28
0.27
0.24
0.27
0.28
0.30
0.28
0.27
0.29
0.28
0.28
0.27
0.27
0.17
0.35
0.26
0.28
0.27
0.29
0.30
0.27
0.29
0.29
0.28
0.28
0.29
0.28
0.32
0.27
0.25
0.27
0.27
0.26
0.25
0.33
0.26
0.26
0.26
0.25
0.26
0.28
0.25
0.27
0.26
0.24
0.25
0.25
0.26
0.25
0.23
0.24
0.26
0.25
Aqua Hawk
127 (mg/L)
0.46
0.51
0.43
0.53
0.53
0.48
0.49
0.46
0.53
0.51
0.50
0.49
0.51
0.46
0.50
0.42
0.55
0.45
0.54
0.46
0.47
0.48
0.48
0.51
0.50
0.52
0.50
0.52
0.47
0.54
0.51
0.49
0.54
0.48
0.51
0.53
0.50
0.53
0.53
0.49
0.46
0.47
0.56
0.51
0.50
0.48
0.52
0.49
0.50
0.47
0.52
0.47
0.50
-------
Table A-l. Daily System Operation Log for Lidgerwood, ND (Continued) (Page 3 of 5)
Date
04/17/05
04/1 8/05
04/19/05
04/20/05
04/21/05
04/22/05
04/23/05
04/24/05
04/25/05
04/26/05
04/27/05
04/28/05
04/29/05
04/30/05
05/01/05
05/02/05
05/03/05
05/04/05
05/05/05
05/06/05
05/07/05
05/08/05
05/09/05
05/10/05
05/1 1/05
05/12/05
05/13/05
05/14/05
05/15/05
05/16/05
05/17/05
05/1 8/05
05/19/05
05/20/05
05/21/05
05/22/05
05/23/05
05/24/05
05/25/05
05/26/05
05/27/05
05/28/05
05/29/05
05/30/05
05/31/05
Daily Plant
Hours
(hrs)
7.1
5.4
6.6
6.5
6.3
6.9
5.4
4.8
7.1
3.9
5.5
4.4
5.8
4.5
5.1
6.7
4.8
6.3
6
7.4
5.1
3.8
6.7
4.6
4.5
5.3
5.5
4.3
4.1
6.1
4.3
5.8
4.8
6.2
7.9
10.2
5.8
6.7
3.8
6.8
4.7
6.3
2.3
6.7
5
Well #1
(hrs)
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
6.6
4.9
6.3
6.0
7.5
5.1
3.8
6.7
4.7
4.5
5.3
5.6
4.2
4.2
6.0
4.4
5.8
4.8
6.3
8.0
10.2
5.8
6.7
3.8
6.8
4.8
6.3
2.4
6.7
5.0
Well #3
(hrs)
4.4
8.2
6.6
6.5
6.3
6.9
5.5
4.8
7.1
4
5.4
4.4
5.9
4.5
5.2
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
Backwash
Pump #1
(hrs)
0
0
0.8
0
0
0.8
0
0
0
0
0.7
0
0
0
0
0.8
0
0
0
0.8
0
0
0
0
0
0.7
0
0
0
0.8
0
0
0
0.6
0
0
0
0
0
0.8
0
0
0
0.7
0
Backwash
Pump #2
(hrs)
0
0
0
0.6
0
0
0
0
0.8
0
0
0
0.8
0
0
0
0
0
0
0
0
0
0
0
0
0
0.8
0
0
0
0
0.7
0
0
0
0
0.8
0
0
0
0.8
0
0
0
0
Reclaim
Pump
(hrs)
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
4.1
2.8
5.2
3.8
0
4.2
4.7
5.1
2.9
3.2
4.8
0
4.7
1.8
3.7
3.4
2.3
6.1
0.1
3.8
4.1
4.8
4.8
7
0.3
4
6.4
2.5
4
1.6
7.9
2.4
0.6
5
Raw Water
(gal)
9362300
9469000
9580700
9692500
9800800
9920600
10013800
10096200
10217600
10285500
10377500
10453500
10554400
10632100
10720200
10835700
10921000
11029900
11132900
11261900
11352200
11415600
11532600
11613900
11692100
11783300
11880600
11955800
12027200
12133600
12209000
12309500
12392600
12502300
12640800
12818500
12920200
13037200
13103300
13223000
13305700
13416200
13457300
13574200
13662000
(gpm)
416.7
216.9
282.1
286.7
286.5
289.4
282.4
286.1
285.0
282.9
284.0
287.9
285.0
287.8
282.4
291.7
290.1
288.1
286.1
286.7
295.1
278.1
291.0
288.3
289.6
286.8
289.6
298.4
283.3
295.6
285.6
288.8
288.5
290.2
288.5
290.4
292.2
291.0
289.9
293.4
287.2
292.3
285.4
290.8
292.7
Reclaim Water
(gal)
7443680
7443680
7449690
7449760
7457660
7459650
7467710
7473480
7473480
7479780
7485960
7492590
7497860
7505110
7510960
7510960
7517600
7524590
7532630
7536890
7545020
7549220
7549220
7556450
7559180
7564930
7570120
7576880
7583150
7583200
7589280
7595450
7602900
7609930
7620530
7620960
7626920
7636910
7640630
7647040
7652470
7661760
7665310
7666240
7674120
(gpm)
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
31.4
23.2
25.7
NA
26.3
24.8
26.3
24.5
42.3
14.6
NA
25.6
25.3
25.9
25.4
49.0
17.1
8.3
26.7
25.1
25.9
24.4
25.2
23.9
24.8
26.0
24.8
26.7
56.6
19.6
24.7
25.8
26.3
Treated
Water
(kgal)
299962
300048
300135
300223
300323
300421
300506
300588
300672
300742
300806
300881
300959
301033
301115
301198
301287
301370
301463
301566
301652
301711
301800
301877
301955
302017
302092
302169
302231
302313
302385
302454
302536
302630
302757
302908
302977
303090
303151
303245
303313
303412
303451
303538
303621
FeClj
(mg/L)
.06
.31
.13
.17
.16
.18
.18
.19
.16
.20
.11
.26
.26
.38
.28
.29
.29
.43
.37
.19
.16
.15
.20
.14
.18
.11
.20
.20
.19
.17
.14
.20
.15
.18
.15
.14
.14
.18
.12
.15
.17
.19
.23
.24
.28
Aqua Hawk 9207
PWG (mg/L)
0.23
0.28
0.25
0.27
0.26
0.25
0.26
0.24
0.24
0.24
0.25
0.24
0.24
0.28
0.23
0.26
0.24
0.24
0.25
0.25
0.25
0.24
0.24
0.23
0.26
0.24
0.21
0.24
0.25
0.25
0.24
0.24
0.24
0.26
0.25
0.25
0.24
0.26
0.21
0.26
0.25
0.24
0.25
0.24
0.23
Aqua Hawk
127 (mg/L)
0.44
0.56
0.50
0.50
0.50
0.50
0.50
0.47
0.49
0.47
0.53
0.55
0.48
0.51
0.48
0.50
0.48
0.50
0.51
0.52
0.48
0.48
0.50
0.55
0.50
0.50
0.51
0.49
0.50
0.49
0.50
0.71
0.51
0.53
0.50
0.49
0.49
0.50
0.46
0.53
0.48
0.48
0.51
0.54
0.54
-------
Table A-l. Daily System Operation Log for Lidgerwood, ND (Continued) (Page 4 of 5)
Date
06/01/05
06/02/05
06/03/05
06/04/05
06/05/05
06/06/05
06/07/05
06/08/05
06/09/05
06/10/05
06/11/05
06/12/05
06/13/05
06/14/05
06/15/05
06/16/05
06/17/05
06/1 8/05
06/19/05
06/20/05
06/21/05
06/22/05
06/23/05
06/24/05
06/25/05
06/26/05
06/27/05
06/28/05
06/29/05
06/30/05
07/01/05
07/02/05
07/03/05
07/04/05
07/05/05
07/06/05
07/07/05
07/08/05
07/09/05
07/10/05
07/11/05
07/12/05
07/13/05
07/14/05
07/15/05
07/16/05
07/17/05
07/1 8/05
07/19/05
07/20/05
07/21/05
07/22/05
07/23/05
Daily Plant
Hours
(hrs)
5.1
5.5
5.4
4.9
5.2
5.9
6.2
6.6
4.1
7.5
4.4
4.3
6.1
5.6
4.6
5.2
6.5
4.7
5.8
5.8
5.8
7.5
6.2
7
6.4
5.3
6.6
6
6.6
6
5.8
5.5
4.8
5.6
6.2
5.3
6.2
6.4
4.8
6.7
6.2
7
7.8
5.7
10.2
7.3
8.7
9.8
9.3
10.9
10.1
12.3
8.7
Well #1
(hrs)
5.1
0.9
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
5.5
4.8
5.6
6.3
5.3
6.3
6.3
4.8
6.8
6.2
7.0
7.9
5.7
10.2
NA
16.1
9.8
9.4
10.9
10.2
12.3
8.7
Well #3
(hrs)
NA
4.6
5.3
5
5.2
6
6.2
6.7
4
7.5
4.5
4.2
6.2
5.6
4.6
5.2
6.5
4.8
5.8
5.9
5.8
7.5
6.2
NA
13.5
5.3
NA
NA
6.6
6.2
5.7
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
Backwash
Pump #1
(hrs)
0
0
0.8
0
0
0
0
0.8
0
0
0
0
0.7
0
0
0
0.8
0
0
0
0
1.5
0
0.8
0
0
0.6
0
0
0
0
0.8
0
0
0.7
0
0
0.8
0
0
0
0.8
0
0
0.6
0
0
0
0.6
0
0
0
0
Backwash
Pump #2
(hrs)
0.7
NA
0.9
0
0
0.8
0
0
0
0.8
0
0
0
0
0.6
0
0
0
0
0.7
0
0.2
0.8
0
0.7
0
0
0
0.8
0.9
0
0
0
0.8
0
0
0.7
0
0
0
0.8
0
0.8
0
0
0
0
0.8
0
0.7
0
0
0
Reclaim
Pump
(hrs)
3.7
4.6
4.2
5
5.2
0
5.1
4.5
3.8
4.7
4.7
4.2
4.3
5.2
3.6
5.2
5.3
4.8
4.1
0
3.5
1.4
3.8
4.8
3.8
NA
NA
7.9
5.5
3.8
5.7
3.7
4.8
2.6
3.9
5.3
3.1
3.1
6.9
4.9
0
4.5
6
5.7
2 2
7.9
0
2.3
7.1
0
8.3
0
8.5
Raw Water
(gal)
13752800
13846900
13938600
14023900
14113400
14216600
14321900
14437600
14506100
14635100
14713000
14785500
14892800
14989100
15067900
15157600
15270100
15352400
15451300
15553300
15652200
15782200
15889500
16010700
16120100
16211600
16327000
16429400
16543400
16650400
16749100
16846100
16929300
17027800
17137500
17230700
17340200
17450800
17536700
17654300
17765900
17886400
18023500
18124100
18302700
18432100
18584500
18757700
18920200
19113900
19290600
19507200
19659800
(gpm)
296.7
340.9
288.4
284.3
286.9
286.7
283.1
287.8
285.4
286.7
288.5
287.7
288.4
286.6
285.5
287.5
288.5
285.8
284.2
288.1
284.2
288.9
288.4
NA
135.1
287.7
NA
NA
287.9
287.6
288.6
293.9
288.9
293.2
290.2
293.1
289.7
292.6
298.3
288.2
300.0
286.9
289.2
294.2
291.8
NA
291.7
294.6
288.1
296.2
288.7
293.5
292.3
Reclaim Water
(gal)
7679690
7686950
7693310
7701090
7707800
7707800
7716280
7721360
7727370
7734690
7741770
7748140
7748200
7756150
7761530
7769500
7772860
7772970
7773090
7773090
7773190
7773230
7773320
7780340
7786560
7795040
7795460
7795460
7804270
7810580
7812850
7818870
7826590
7830260
7836640
7844950
7850010
7858300
7866340
7873270
7873270
7880860
7888770
7898130
7904250
7913330
7913330
7920120
7928150
7928280
7941500
7941500
7955190
(gpm)
25.1
26.3
25.2
25.9
21.5
NA
NA
18.8
26.4
26.0
25.1
25.3
0.2
25.5
24.9
25.5
10.6
0.4
0.5
NA
0.5
0.5
0.4
24.4
27.3
NA
NA
NA
26.7
Til
6.6
27.1
26.8
23.5
27.3
26.1
27.2
44.6
19.4
23.6
NA
28.1
22.0
27.4
46.4
19.2
NA
49.2
18.8
NA
26.5
NA
26.8
Treated Water
(kgal)
303696
303784
303847
303931
304015
304096
304188
304282
304344
304449
304529
304593
304677
304761
304820
304908
304991
305073
305165
305258
305341
305423
305513
305620
305708
305795
305884
305971
306062
306147
306234
306313
306386
306474
306561
306650
306734
306820
306911
307013
307105
307204
307316
307412
307561
307683
307812
307949
308082
308240
308400
308573
308720
FeCl3
(mg/L)
.28
.23
.11
.16
.19
.22
.18
.26
.17
.25
.19
.13
.25
.15
.11
.04
.14
.23
.22
.21
.19
.20
.19
.17
.16
22
.21
.14
.15
22
.20
.23
.18
.26
.09
.11
.18
.22
.25
.17
.16
.13
0.42
0.95
0.87
0.86
0.86
0.86
0.82
0.88
0.84
0.84
0.85
Aqua Hawk 9207
PWG (mg/L)
0.27
0.21
0.24
0.24
0.27
0.24
0.24
0.25
0.23
0.23
0.26
0.22
0.28
0.25
0.23
0.22
0.25
0.25
0.24
0.24
0.22
0.25
0.24
0.25
0.23
0.26
NA
0.25
0.25
0.25
0.24
NA
NA
0.23
0.24
0.24
0.25
0.23
0.24
0.24
0.22
0.25
0.24
0.24
0.23
0.24
0.25
0.24
0.24
0.24
0.26
0.26
0.27
Aqua Hawk 127
(mg/L)
0.47
0.51
0.50
0.46
0.49
0.46
0.51
0.47
0.47
0.50
0.46
0.50
0.47
0.57
0.48
0.50
0.45
0.52
0.48
0.50
0.51
0.50
0.51
0.50
0.50
0.47
0.51
0.51
0.48
0.52
0.48
0.49
0.47
0.48
0.53
0.47
0.51
0.50
0.44
0.58
0.50
0.49
0.50
0.49
0.50
0.52
0.49
0.52
0.50
0.53
0.50
0.50
0.50
-------
Table A-l. Daily System Operation Log for Lidgerwood, ND (Continued) (Page 5 of 5)
Date
07/24/05
07/25/05
07/26/05
07/27/05
07/28/05
07/29/05
07/30/05
07/31/05
Daily
Plant
Hours
(hrs)
9.9
6.8
7.8
7.9
5.9
9.3
6.4
10.2
Well #1
(hrs)
10.0
6.8
7.8
7.9
6.0
9.3
6.5
10.1
Well #3
(hrs)
NA
NA
NA
NA
NA
NA
NA
NA
Backwash
Pump #1
(hrs)
0
0
0.8
0
0
0.8
0
0
Backwash
Pump #2
(hrs)
0.8
0
0
0.8
0
0
0
0.7
Reclaim
Pump
(hrs)
7.2
NA
4
0
NA
7.4
6.4
7.3
Raw Water
(gal)
19834600
19954600
20092100
20230600
20336700
20499700
20612300
20791500
(gpm)
291.3
294.1
293.8
292.2
294.7
292.1
288.7
295.7
Reclaim Water
(gal)
7966930
7969760
7969760
7969760
7979460
7981670
7992110
8003920
(gpm)
27.2
NA
NA
NA
NA
5.0
27.2
27.0
Treated
Water
(kgal)
308863
308969
309078
309177
309283
309417
309512
309669
FeCl3
(mg/L)
0.86
0.85
0.84
0.46
0.85
0.82
0.84
0.84
Aqua Hawk
9207 PWG
(mg/L)
0.27
0.26
0.25
0.26
0.25
0.27
0.27
0.26
Aqua Hawk
127 (mg/L)
0.51
0.49
0.49
0.51
0.57
0.51
0.49
0.49
NA = Not Available
>
Lfi
-------
APPENDIX B
ANALYTICAL DATA
-------
Table B-l. Analytical Results from Treatment Plant Sampling at Lidgerwood, ND (Page 1 of 8)
Sampling Date
Sampling Location
Parameter Unit
Alkalinity
Fluoride
Sulfate
NO3 (as N)
Orthophosphate
Silica (as SiO2)
Turbidity
pH
Temperature
DO
ORP
Free Chlorine (as C12)
Total Chlorine (as C12)
Total Hardness
Ca Hardness
Mg Hardness
As (total)
As (soluble)
As (particulate)
As (III)
As(V)
Fe (total)
Fe (soluble)
Mn (total)
Mn (soluble)
mg/Lw
mg/L
mg/L
mg/L
mg/L®
mg/L
NTU
-
°C
mg/L
mV
mg/L
mg/L
mg/L«
mg/L(a)
mg/L«
Hg/L
jig/L
TO/L
Hg/L
Hg/L
tig/L
Hg/L
jig/L
Hg/L
01/04/05
IN
360
0.2
360
<0.04
<0.06
31.5
17
NA(C)
NA(C)
NA(C)
NA(C)
_
_
534
384
149
128
130
<0.1
130
<0.1
1,418
1,356
607
598
BF
372
0.3
340
<0.04
<0.06
31.3
4.8
NA(C)
NA(C)
NA(C)
NA(C)
_
_
539
387
152
72.3
4.9
67.4
0.9
4.0
1,509
<25
609
17.7
AF
351
0.3
330
<0.04
<0.06
31.1
0.4
NA(C)
NA(C)
NA(C)
NA(C)
_
_
551
392
160
7.5
7.5
<0.1
0.9
6.6
<25
<25
2.0
1.5
PC
_
_
_
_
_
_
NA(C)
NA(C)
_
_
NAW
NA(C)
561
395
166
7.5
7.5
<0.1
_
_
<25
<25
2.2
1.2
01/11/05
IN
372
_
_
_
<0.06
31.7
18
7.3
10.7
2.0
NA(C)
_
_
_
_
_
127
_
_
_
1,340
_
667
_
BF
340
_
_
_
<0.06
31.2
5.4
7.4
9.9
5.0
NA(C)
_
_
_
_
_
72.7
_
_
_
1,431
_
638
_
AF
344
_
_
_
<0.06
30.1
0.4
7.5
10.8
5.2
NA(C)
_
_
_
_
_
7.1
_
_
_
<25
_
5.5
_
PC
376
_
_
_
<0.06
31.3
0.4
7.5
11.8
_
_
NA(C)
NA(C)
_
_
_
7.2
_
_
_
<25
_
5.2
_
01/18/05
IN
370
_
_
_
0.2(e)
30.0
18
7.3
10.8
NA(tl)
-11
_
_
_
_
_
125
_
_
_
1,352
_
613
_
BF
366
_
_
_
<0.05
25.6
6.1
7.4
10.6
NA(d)
324
_
_
_
_
_
75.1
_
_
_
1,616
_
500
_
AF
353
_
_
_
<0.05
29.6
O.I
7.5
11.1
NA(d)
253
_
_
_
_
_
7.0
_
_
_
<25
_
79.1
_
PC
374
_
_
_
<0.05
30.2
O.I
7.9
11.6
_
_
0.1
1.8
_
_
_
7.4
_
_
_
<25
_
110
_
01/25/05
IN
388
_
_
_
O.05
29.0
17
7.3
10.2
3.3
-26
_
_
_
_
_
117
_
_
_
1,419
_
567
_
BF
379
_
_
_
<0.05
29.3
5.3
7.4
11.3
6.3
423
_
_
_
_
_
68.9
_
_
_
1,519
_
572
_
AF
361
_
_
_
O.05
29.4
2.0
7.5
12.2
6.1
360
_
_
_
_
_
7.5
_
_
_
43.3
_
34.7
_
PC
384
_
_
_
<0.05
28.6
0.2
7.5
12.2
_
_
0.1
4.1
_
_
_
6.7
_
_
_
<25
_
13.6
_
(a) as CaCOs; (b) as PO4; (c) On-site water quality parameter not measured; (d) DO probe not operational.
IN = at wellhead; BF = before filter; AF = after filter; PC = post-chlorination from clearwell (no speciation or DO/ORP measurements); NA = data not available.
-------
Table B-l. Analytical Results from Treatment Plant Sampling at Lidgerwood, ND (Page 2 of 8)
Sampling Date
Sampling Location
Parameter Unit
Alkalinity
Fluoride
Sulfate
NO3 (as N)
Orthophosphate
Silica (as SiO2)
Turbidity
pH
Temperature
DO
ORP
Free Chlorine (as C12)
Total Chlorine (as C12)
Total Hardness
Ca Hardness
Mg Hardness
As (total)
As (soluble)
As (particulate)
As (III)
As(V)
Fe (total)
Fe (soluble)
Mn (total)
Mn (soluble)
mS/L<*
mg/L
mg/L
mg/L
mg/L*
mg/L
NTU
-
°C
mg/L
mV
mg/L
mg/L
mg/L(a
mg/L(a
mg/L(a
Hg/L
Hg/L
Hg/L
Hg/L
Hg/L
Hg/L
Hg/L
Hg/L
Hg/L
02/01/05
IN
453
0.2
385
<0.05
<0.05
29.6
14
7.3
11.2
1.7
-24
-
-
552
392
159
151
146
4.9
130
15.7
1,097
1,032
824
868
BF
369
0.3
324
<0.05
<0.05
29.1
6.3
7.4
12.1
6.1
395
-
-
585
414
171
59.2
6.6
52.7
2.1
4.4
1,151
<25
637
31.1
AF
355
0.2
316
<0.05
<0.05
29.1
<0.1
7.4
12.2
6.0
340
-
-
567
401
165
7.6
7.4
0.2
2.0
5.4
<25
<25
10.2
10.7
PC
-
-
-
-
-
-
-
7.5
12.3
-
-
0.0
1.4
591
418
173
7.4
7.6
<0.1
-
-
<25
<25
15.7
10.4
02/08/05
IN
401
-
-
-
<0.05
30.9
12
7.3
10.5
1.6
-27
-
-
-
-
-
125
-
-
-
-
967
-
606
-
BF
415
-
-
-
<0.05
30.3
5.4
7.5
11.0
6.0
440
-
-
-
-
-
81.3
-
-
-
-
1,458
-
653
-
AF
406
-
-
-
<0.05
30.5
0.1
7.5
11.5
5.8
353
-
-
-
-
-
8.7
-
-
-
-
<25
-
3.9
-
PC
388
-
-
-
<0.05
31.3
12
7.6
11.0
-
-
0.1
3.5
-
-
-
9.2
-
-
-
-
<25
-
8.4
-
02/15/05
IN
401
-
-
-
<0.05
32.9
13
7.3
9.5
3.4
-23
-
-
-
-
-
131
-
-
-
-
1,024
-
695
-
BF
419
-
-
-
<0.05
30.0
4.9
7.5
10.3
5.8
366
-
-
-
-
-
73.4
-
-
-
-
1,472
-
700
-
AF
410
-
-
-
<0.05
32.0
<0.1
7.5
11.3
5.5
274
-
-
-
-
-
7.8
-
-
-
-
<25
-
3.1
-
PC
401
-
-
-
<0.05
31.7
0.5
7.6
11.2
-
-
0.1
3.9
-
-
-
7.9
-
-
-
-
<25
-
6.9
-
02/22/05
IN
396
-
-
-
<0.05
31.0
18
7.3
9.3
1.8
-29
-
-
-
-
-
126
-
-
-
-
1,252
-
670
-
BF
400
-
-
-
<0.05
29.6
4.9
7.5
10.3
5.7
339
-
-
-
-
-
75.0
-
-
-
-
1,359
-
634
-
AF
400
-
-
-
<0.05
30.3
0.2
7.5
10.8
5.9
275
-
-
-
-
-
8.0
-
-
-
-
<25
-
2.5
-
PC
392
-
-
-
<0.05
30.8
<0.1
7.5
11.0
-
-
0.1
3.4
-
-
-
8.4
-
-
-
-
<25
-
3.0
-
(a) as
s; (b) as PO^ IN = at wellhead; BF = before filter; AF = after filter; PC = post-chlorination from clearwell (no speciation or DO/ORP measurements); NA = data not available.
-------
Table B-l. Analytical Results from Treatment Plant Sampling at Lidgerwood, ND (Page 3 of 8)
Sampling Date
Sampling Location
Parameter Unit
Alkalinity
Fluoride
Sulfate
NO3 (as N)
Orthophosphate
Silica (as SiO2)
Turbidity
pH
Temperature
DO
ORP
Free Chlorine (as C12)
Total Chlorine (as C12)
Total Hardness
Ca Hardness
Mg Hardness
As (total)
As (soluble)
As (particulate)
As (III)
As(V)
Fe (total)
Fe (soluble)
Mn (total)
Mn (soluble)
mg/Lw
mg/L
mg/L
mg/L
mg/L«
mg/L
NTU
-
°C
mg/L
mV
mg/L
mg/L
mg/L(a)
mg/Lw
mg/L(a)
jig/L
jig/L
jig/L
jig/L
jig/L
jig/L
jig/L
jig/L
jig/L
03/01/05
IN
714
0.1
328
0.05
<0.05
31.3
12
7.3
9.5
2.0
-22
-
-
452
321
130
144
135
9.3
124
11.5
1,116
1,124
748
807
BF
682
0.2
331
<0.05
<0.05
24.9
5.4
7.4
10.4
5.4
432
-
-
416
290
126
100
7.4
92.8
1.8
5.6
1,584
<25
714
7.2
AF
691
0.2
332
<0.05
<0.05
30.4
0.4
7.5
10.8
5.7
256
-
-
425
301
124
10.3
8.8
1.6
1.9
6.8
<25
<25
3.4
3.5
PC
-
-
-
-
-
-
-
7.6
10.5
-
-
0.3
0.3
445
317
128
10.3
9.8
0.5
-
-
<25
-
3.5
-
03/08/05
IN
379
-
-
-
<0.05
31.4
19
7.3
9.6
2.7
-29
-
-
-
-
-
158
-
-
-
-
1,503
-
624
-
BF
370
-
-
-
<0.05
31.9
4.0
7.4
10.3
5.3
189
-
-
-
-
-
94.9
-
-
-
-
1,777
-
744
-
AF
370
-
-
-
<0.05
30.8
0.4
7.4
10.6
5.5
163
-
-
-
-
-
9.2
-
-
-
-
<25
-
18.2
-
PC
370
-
-
-
<0.05
31.2
0.4
7.5
10.7
-
-
0.1
2.1
-
-
-
9.2
-
-
-
-
<25
-
15.2
-
03/15/05
IN
384
-
-
-
0.2(c)
34.2
18
7.3
9.7
2.3
-29
-
-
-
-
-
133
-
-
-
-
1,366
-
733
-
BF
366
-
-
-
<0.05
33.3
5.1
7.4
10.5
5.1
456
-
-
-
-
-
84.0
-
-
-
-
1,731
-
830
-
AF
361
-
-
-
<0.05
33.2
0.2
7.4
10.7
5.3
306
-
-
-
-
-
6.3
-
-
-
-
<25
-
5.7
-
PC
366
-
-
-
<0.05
33.1
0.1
7.5
11.0
-
-
0.3
5.2
-
-
-
7.0
-
-
-
-
<25
-
6.1
-
03/22/05
IN
377
-
-
-
<0.05
31.7
13
7.3
9.8
1.3
-33
-
-
-
-
-
132
-
-
-
-
1,517
-
962
-
BF
364
-
-
-
<0.05
30.9
4.4
7.3
10.1
5.0
463
-
-
-
-
-
79.5
-
-
-
-
1,555
-
1,031
-
AF
355
-
-
-
<0.05
30.6
0.9
7.3
10.6
4.8
393
-
-
-
-
-
8.4
-
-
-
-
<25
-
64.2
-
PC
369
-
-
-
<0.05
31.5
1.5
7.4
11.4
-
-
0.2
4.3
-
-
-
8.8
-
-
-
-
29.0
-
76.0
-
(a) as CaCO3; (b) as PO4; (c) Orthophosphate levels non-detect based on total phosphorous data from ICP-MS. This value considered as an outlier and not included in review of the water quality.
IN = at wellhead; BF = before filter; AF = after filter; PC = post-chlorination from clearwell (no speciation or DO/ORP measurements); NA = data not available.
-------
Table B-l. Analytical Results from Treatment Plant Sampling at Lidgerwood, ND (Page 4 of 8)
Sampling Date
Sampling Location
Parameter Unit
Alkalinity
Fluoride
Sulfate
NO3 (as N)
Orthophosphate
Silica (as SiO2)
Turbidity
pH
Temperature
DO
ORP
Free Chlorine (as C12)
Total Chlorine (as C12)
Total Hardness
Ca Hardness
Mg Hardness
As (total)
As (soluble)
As (particulate)
As (III)
As(V)
Fe (total)
Fe (soluble)
Mn (total)
Mn (soluble)
mg/L(1)
mg/L
mg/L
mg/L
mg/L""
mg/L
NTU
-
°C
mg/L
mV
mg/L
mg/L
mg/L*'1
mg/L("
mg/Lw
Hg/L
Hg/L
Hg/L
Hg/L
Hg/L
Hg/L
Hg/L
Hg/L
Hg/L
03/29/05
IN
376
-
-
-
<0.05
31.4
16
7.4
10.0
3.4
-35
-
-
-
-
-
126
-
-
-
-
1,454
-
1,067
-
BF
352
-
-
-
<0.05
31.2
3.1
7.4
11.2
5.1
387
-
-
-
-
-
60.4
-
-
-
-
1,243
-
562
-
AF
352
-
-
-
0.28(tl)
29.3
0.2
7.4
11.4
5.0
383
-
-
-
-
-
7.5
-
-
-
-
<25
-
2.5
-
PC
354
-
-
-
<0.05
30.6
1.3
7.5
11.0
-
-
0.1
8.0(c)
-
-
-
7.1
-
-
-
-
<25
-
28.2
-
04/05/05
IN
418
0.2
323
<0.05
<0.05
31.3
12
7.6
10.2
3.6
-31
-
-
451
333
118
132
124
7.3
125
<0.1
1,163
532
761
762
BF
409
0.6
309
<0.05
<0.05
32.9
5.2
7.4
10.5
4.8
378
-
-
454
322
131
105
6.6
98.0
3.5
3.1
1,700
<25
824
24.6
AF
405
0.4
309
<0.05
<0.05
30.5
0.2
7.4
11.3
4.7
270
-
-
483
345
137
9.2
8.3
0.9
3.1
5.2
<25
<25
1.3
1.1
PC
-
-
-
-
-
-
-
7.5
11.7
-
-
0.1
3.3
467
342
125
7.3
7.9
<0.1
-
<25
<25
5.1
4.9
04/12/05
IN
417
-
-
-
<0.05
32.0
11
7.4
10.1
2.8
-27
-
-
-
-
-
127
-
-
-
-
1,076
-
707
-
BF
404
-
-
-
<0.05
32.1
4.8
7.4
10.6
4.8
248
-
-
-
-
-
86.4
-
-
-
-
1,612
-
709
-
AF
400
-
-
-
<0.05
31.1
0.2
7.4
11.0
4.9
193
-
-
-
-
-
8.0
-
-
-
-
<25
-
2.5
-
PC
413
-
-
-
<0.05
31.6
1.2
7.5
11.8
-
-
0.2
3.9
-
-
-
7.6
-
-
-
-
<25
-
38.6
-
04/18/05
IN
424
422
-
-
-
<0.05
<0.05
32.0
31.9
13
12
7.4
9.9
3.1
-30
-
-
-
-
-
138
114
-
-
-
-
1,209
1,065
-
754
658
-
BF
424
400
-
-
-
<0.05
<0.05
31.4
32.1
5.4
5.7
7.5
10.5
4.6
391
-
-
-
-
-
95.9
94.0
-
-
-
-
1,929
1,787
-
891
908
-
AF
413
400
-
-
-
<0.05
<0.05
31.7
31.3
0.8
0.2
7.5
10.9
4.7
271
-
-
-
-
-
10.6
12.5
-
-
-
-
29.2
29.8
-
11.2
9.9
-
PC
401
400
-
-
-
<0.05
<0.05
31.9
31.7
0.1
0.2
7.6
11.2
-
-
0.1
3.7
-
-
-
13.0
14.0
-
-
-
-
188
194
-
1.6
2 2
-
(a) as CaCO3; (b) as PO4; (c) Chlorine rotometers plugged during prior operations. Total chlorine levels adjusted higher after repair; (d) Orthophosphate levels non-detect based on total phosphorous data from ICP-MS. This value
considered as an outlier and not included in review of the water quality. IN = at wellhead; BF = before filter; AF = after filter; PC = post-chlorination from clearwell (no speciation or DO/ORP measurements); NA = data not
available.
-------
Table B-l. Analytical Results from Treatment Plant Sampling at Lidgerwood, ND (Page 5 of 8)
Sampling Date
Sampling Location
Parameter Unit
Alkalinity
Fluoride
Sulfate
NO3 (as N)
Orthophosphate
Silica (as SiO2)
Turbidity
pH
Temperature
DO
ORP
Free Chlorine (as C12)
Total Chlorine (as C12)
Total Hardness
Ca Hardness
Mg Hardness
As (total)
As (soluble)
As (particulate)
As (III)
As(V)
Fe (total)
Fe (soluble)
Mn (total)
Mn (soluble)
mg/L("
mg/L
mg/L
mg/L
mg/L(b)
mg/L
NTU
-
°C
mg/L
mV
mg/L
mg/L
mg/L(1)
mg/L("
mg/L(1)
Hg/L
Hg/L
Hg/L
Hg/L
Hg/L
Hg/L
Hg/L
Hg/L
Hg/L
04/26/05
IN
422
-
-
-
0.07M
32.6
3.5
7.4
10.1
2 2
-32
-
-
-
-
-
137
-
-
-
-
1,128
-
695
-
BF
405
-
-
-
0.07W
32.0
3.5
7.4
11.0
4.6
363
-
-
-
-
-
70.0
-
-
-
-
1,184
-
495
-
AF
409
-
-
-
<0.05
30.9
0.2
7.4
11.3
4.6
264
-
-
-
-
-
9.9
-
-
-
-
<25
-
4.1
-
PC
408
-
-
-
0.07(d)
32.4
0.3
7.5
11.6
-
-
0.3
4.0
-
-
-
9.7
-
-
-
-
<25
-
6.6
-
05/03/05
IN
408
0.2
372
<0.05
<0.05
31.2
15
7.2
10.1
2 2
-34
-
-
502
351
151
134
137
<0.1
122
14.8
1,557
1,524
668
652
BF
395
0.3
348
<0.05
<0.05
30.5
3.8
7.3
10.7
4.4
334
-
-
504
351
154
64.4
4.3
60.1
1.0
3.3
1,583
<25
535
5.8
AF
408
0.3
367
<0.05
<0.05
30.1
0.3
7.3
11.0
4.3
267
-
-
467
326
141
7.6
7.4
0.3
1.0
6.3
<25
<25
3.1
1.5
PC
-
-
-
-
-
-
-
7.4
11.4
-
-
0.1
4.1
-
-
-
8.4
8.2
0.2
-
-
<25
<25
1.6
1.9
05/11/05
IN
383
-
-
-
<0.05
31
17
7.4
9.7
2.5
-33
-
-
-
-
-
134
-
-
-
-
1,300
-
627
-
BF
370
-
-
-
<0.05
31.4
3.7
7.4
10.6
4.3
315
-
-
-
-
-
82.0
-
-
-
-
1,433
-
538
-
AF
378
-
-
-
<0.05
30.0
0.2
7.4
11.6
4.3
258
-
-
-
-
-
7.3
-
-
-
-
<25
-
1.1
-
PC
365
-
-
-
<0.05
31.3
0.7
7.5
11.8
-
-
0.4
3.7
-
-
-
6.0
-
-
-
-
<25
-
0.9
-
05/17/05
IN
387
-
-
-
<0.05
30.9
15
7.4
10.3
NA(C)
-37
-
-
-
-
-
120
-
-
-
-
1,463
-
646
-
BF
374
-
-
-
<0.05
31.1
4.0
7.3
10.9
NA(C)
254
-
-
-
-
-
67.6
-
-
-
-
1,435
-
509
-
AF
374
-
-
-
<0.05
30.6
0.4
7.4
11.5
NA(C)
185
-
-
-
-
-
6.8
-
-
-
-
<25
-
1.1
-
PC
370
-
-
-
<0.05
31.6
0.3
7.5
12.0
-
-
0.1
2.5
-
-
-
7.0
-
-
-
-
<25
-
1.9
-
(a) as CaCO3; (b) as PO4:
IN = at wellhead; BF =
(c) DO probe
before filter;
not working properly; (d) Orthophosphate levels non-detect based on total phosphorous data from ICP-MS. This value considered as an outlier and not included in review of the water quality.
AF = after filter; PC = post-chlorination from clearwell (no speciation or DO/ORP measurements); NA = data not available.
-------
Table B-l. Analytical Results from Treatment Plant Sampling at Lidgerwood, ND (Page 6 of 8)
Sampling Date
Sampling Location
Parameter Unit
Alkalinity
Fluoride
Sulfate
NO3 (as N)
Orthophosphate
Silica (as SiO2)
Turbidity
pH
Temperature
DO
ORP
Free Chlorine (as C12)
Total Chlorine (as C12)
Total Hardness
Ca Hardness
Mg Hardness
As (total)
As (soluble)
As (particulate)
As (III)
As(V)
Fe (total)
Fe (soluble)
Mn (total)
Mn (soluble)
mg/L*"
mg/L
mg/L
mg/L
mg/L"»
mg/L
NTU
-
°C
mg/L
mV
mg/L
mg/L
mg/L*"
mg/L*"
mg/L*"
Hg/L
Hg/L
Hg/L
Hg/L
Hg/L
Hg/L
Hg/L
Hg/L
Hg/L
05/24/05
IN
384
-
-
-
<0.05
30.8
16
7.3
10.4
NA(C)
-36
-
-
-
-
-
118
-
-
-
-
2,606
-
672
-
BF
366
-
-
-
<0.05
30.5
3.8
7.3
11.1
NA(C)
286
-
-
-
-
-
62.7
-
-
-
-
2,389
-
535
-
AF
375
-
-
-
<0.05
29.8
0.5
7.3
10.8
NA(C)
179
-
-
-
-
-
6.5
-
-
-
-
<25
-
1.6
-
PC
379
-
-
-
<0.05
30.8
0.4
7.4
11.4
-
-
0.2
3.0
-
-
-
6.6
-
-
-
-
<25
-
5.8
-
05/31/05
IN
390
-
-
-
<0.05
31.4
18
7.4
9.7
NA(C)
-35
-
-
-
-
-
113
-
-
-
-
1,476
-
666
-
BF
381
-
-
-
<0.05
30.6
4.5
7.3
10.6
NA(C)
308
-
-
-
-
-
69.4
-
-
-
-
1,625
-
585
-
AF
376
-
-
-
<0.05
29.7
0.3
7.3
10.7
NA(C)
197
-
-
-
-
-
8.3
-
-
-
-
<25
-
4.5
-
PC
372
-
-
-
<0.05
30.9
0.3
7.4
11.4
-
-
0.1
3.0
-
-
-
6.1
-
-
-
-
<25
-
4.1
-
06/07/05
IN
414
-
-
-
<0.05
31.5
23
7.3
9.8
NA(C)
-29
-
-
-
-
-
128
-
-
-
-
737
-
606
-
BF
396
-
-
-
<0.05
31.2
4.3
7.4
11.1
NA(C)
236
-
-
-
-
-
66.1
-
-
-
-
801
-
452
-
AF
427
-
-
-
<0.05
31.1
<0.1
7.3
11.2
NA(C)
294
-
-
-
-
-
8.3
-
-
-
-
<25
-
1.6
-
PC
396
-
-
-
<0.05
31.7
0.1
7.5
11.4
-
-
0.1
3.7
-
-
-
8.1
-
-
-
-
<25
-
1.8
-
06/14/05
IN
414
0.1
355
<0.05
<0.05
32.2
14
7.3
10.1
NA(C)
-31
-
-
481
335
146
139
134
4.8
128
6.2
1,341
1,154
683
617
BF
409
0.2
352
0.1
<0.05
31.5
4.7
7.3
10.7
NA(C)
320
-
-
426
312
113
73.0
5.8
67.2
2.9
2.9
1,370
<25
637
24.2
AF
396
0.2
367
0.2
<0.05
30.8
0.1
7.3
11.3
NA(C)
233
-
-
403
273
130
8.9
9.0
<0.1
3.1
5.9
<25
<25
3.8
3.1
PC
-
-
-
-
-
-
-
7.4
11.8
-
-
0.2
3.5
404
274
130
9.0
9.6
<0.1
-
-
<25
<25
6.7
6.6
(a) as CaCO3. (b) as PO4; (c) DO probe not working properly. IN = at wellhead; BF = before filter; AF = after filter; PC = post-chlorination from clearwell (no speciation or DO/ORP measurements); NA = data not
available.
-------
Table B-l. Analytical Results from Treatment Plant Sampling at Lidgerwood, ND (Page 7 of 8)
Sampling Date
Sampling Location
Parameter Unit
Alkalinity
Fluoride
Sulfate
NO3 (as N)
Orthophosphate
Silica (as SiO2)
Turbidity
pH
Temperature
DO
ORP
Free Chlorine (as C12)
Total Chlorine (as C12)
Total Hardness
Ca Hardness
Mg Hardness
As (total)
As (soluble)
As (particulate)
As (III)
As(V)
Fe (total)
Fe (soluble)
Mn (total)
Mn (soluble)
mg/L("
mg/L
mg/L
mg/L
mg/L*'
mg/L
NTU
-
°C
mg/L
mV
mg/L
mg/L
mg/L<"
mg/L("
mg/L("
Hg/L
Hg/L
Hg/L
Hg/L
Hg/L
Hg/L
Hg/L
Hg/L
Hg/L
06/21/05
IN
396
-
-
-
<0.05
30.4
13
7.3
10.1
NA(C)
-13
-
-
-
-
-
147
-
-
-
-
1,078
-
681
-
BF
387
-
-
-
<0.05
30.2
4.9
7.4
10.5
NA(C)
251
-
-
-
-
-
99.2
-
-
-
-
1,563
-
690
-
AF
396
-
-
-
<0.05
30.3
0.7
6.4
11.2
NA(C)
186
-
-
-
-
-
14.3
-
-
-
-
64.4
-
27.1
-
PC
396
-
-
-
<0.05
30.0
0.3
7.5
11.9
-
-
0.1
2.0
-
-
-
11.6
-
-
-
-
<25
-
8.7
-
06/28/05
IN
396
-
-
-
<0.05
30.8
19
7.4
10.1
NA(C)
-28
-
-
-
-
-
136
-
-
-
-
965
-
657
-
BF
378
-
-
-
<0.05
30.9
14
7.3
10.7
NA(C)
319
-
-
-
-
-
87.7
-
-
-
-
1,340
-
612
-
AF
374
-
-
-
<0.05
30.2
7.1
7.4
11.4
NA(C)
213
-
-
-
-
-
11.4
-
-
-
-
<25
-
3.6
-
PC
374
-
-
-
<0.05
30.5
16
7.5
11.9
-
-
0.6
3.8
-
-
-
10.2
-
-
-
-
<25
-
1.9
-
07/06/05((1)
IN
352
-
-
-
<0.05
31.2
20
7.4
9.8
4.1
-32
-
-
-
-
-
124
-
-
-
-
1,486
-
679
-
BF
352
-
-
-
<0.05
28.8
6.2
7.3
10.5
6.0
284
-
-
-
-
-
92.0
-
-
-
-
1,947
-
789
-
AF
352
-
-
-
<0.05
31.2
0.3
7.3
11.1
6.0
172
-
-
-
-
-
7.0
-
-
-
-
<25
-
4.5
-
PC
352
-
-
-
<0.05
31.2
0.4
7.4
11.9
-
-
0.1
4.0
-
-
-
6.5
-
-
-
-
<25
-
3.3
-
07/12/05
IN
352
<0.1
349
<0.05
<0.05
29.5
20
7.2
10.1
2 2
-34
-
-
526
374
152
125
117
8.3
116
1.0
1,779
1,480
778
647
BF
352
0.2
348
0.06
<0.05
29.3
7.3
7.2
11.1
6.1
190
-
-
564
405
158
77.3
5.7
71.6
<0.1
5.6
1,928
<25
642
9.9
AF
352
0.2
348
0.05
<0.05
28.8
1.2
7.2
11.0
6.1
260
-
-
527
379
148
8.6
3.7
4.9
<0.1
3.6
<25
105
146
52.1
PC
-
-
-
-
-
-
-
7.4
11.5
-
-
0.1
1.4
516
369
147
8.4
8.3
0.1
-
-
<25
<25
162
146
(a) as CaCO3; (b) as PO4; (c) DO probe not working properly; (d) Replacement DO probe received. IN = at wellhead; BF = before filter; AF = after filter; PC = post-chlorination from clearwell (no speciation or DO/ORP
measurements); NA = data not available.
-------
Table B-l. Analytical Results from Treatment Plant Sampling at Lidgerwood, ND (Page 8 of 8)
Sampling Date
Sampling Location
Parameter Unit
Alkalinity
Fluoride
Sulfate
NO3 (as N)
Orthophosphate
Silica (as SiO2)
Turbidity
pH
Temperature
DO
ORP
Free Chlorine (as C12)
Total Chlorine (as C12)
Total Hardness
Ca Hardness
Mg Hardness
As (total)
As (soluble)
As (particulate)
As (III)
As(V)
Fe (total)
Fe (soluble)
Mn (total)
Mn (soluble)
mg/L(1)
mg/L
mg/L
mg/L
mg/L(b)
mg/L
NTU
-
°C
mg/L
mV
mg/L
mg/L
mg/Lw
mg/L(1)
mg/L("
Hg/L
Hg/L
Hg/L
Hg/L
Hg/L
Hg/L
Hg/L
Hg/L
Hg/L
07/19/05
IN
361
-
-
-
<0.05
31.3
20
7.3
9.7
2.5
-22
-
-
-
-
-
119
-
-
-
-
1,472
-
567
-
BF
352
-
-
-
<0.05
31.2
5.3
7.4
10.4
6.4
320
-
-
-
-
-
96.5
-
-
-
-
1,795
-
959
-
AF
352
-
-
-
<0.05
30.3
0.3
7.5
10.9
6.2
215
-
-
-
-
-
9.0
-
-
-
-
<25
-
8.5
-
PC
352
-
-
-
<0.05
31.0
0.2
7.5
11.4
-
-
0.1
4.0
-
-
-
8.4
-
-
-
-
<25
-
5.4
-
07/25/05
IN
361
-
-
-
<0.05
29.8
20
7.4
10.2
3.2
-23
-
-
-
-
-
115
-
-
-
-
1,763
-
687
-
BF
334
-
-
-
<0.05
28.6
4.8
7.5
10.9
6.4
330
-
-
-
-
-
80.0
-
-
-
-
1,776
-
627
-
AF
339
-
-
-
<0.05
29.2
<0.1
7.4
11.1
6.4
228
-
-
-
-
-
8.6
-
-
-
-
<25
-
2.2
-
PC
348
-
-
-
<0.05
29.5
0.4
7.6
11.7
-
-
0.1
4.2
-
-
-
8.1
-
-
-
-
<25
-
2.3
-
(a) as CaCO3; (b) as PO4; I IN = at wellhead; BF =
(no speciation or DO/ORP measurements); NA =
before filter; AF = after filter; PC = post-chlorination from clearwell
data not available.
------- |