EPA/600/R-09/144
December 2009
Arsenic Removal from Drinking Water
by Iron Removal and Adsorptive Media
U.S. EPA Demonstration Project at Stewart, MN
Final Performance Evaluation Report
by
Wendy E. Condit
Abraham S.C. Chen
Lili Wang
Anbo Wang
Battelle
Columbus, OH 43201-2693
Contract No. 68-C-00-185
Task Order No. 0029
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 was funded by the United States Environmental Protection Agency
(EPA) under Task Order 0029 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 U.S. Environmental Protection Agency (EPA) is charged by Congress with protecting the nation's
land, air, and water resources. Under a mandate of national environmental laws, the Agency strives to
formulate and implement actions leading to a compatible balance between human activities and the ability
of natural systems to support and nurture life. To meet this mandate, EPA's research program is
providing data and technical support for solving environmental problems today and building a science
knowledge base necessary to manage our ecological resources wisely, understand how pollutants affect
our health, and prevent or reduce environmental risks in the future.
The National Risk Management Research Laboratory (NRMRL) is the Agency's center for investigation
of technological and management approaches for preventing and reducing risks from pollution that
threaten human health and the environment. The focus of the Laboratory's research program is on
methods and their cost-effectiveness for prevention and control of pollution to air, land, water, and
subsurface resources; protection of water quality in public water systems; remediation of contaminated
sites, sediments, and 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 from the 1-year U.S.
Environmental Protection Agency (EPA) arsenic-removal technology demonstration project at the
Stewart, MN, facility. The main objective of the project was to evaluate the effectiveness of Siemens'
Type IIAERALATER® system for iron removal, as well as AdEdge Technologies' Arsenic Package Unit
(APU)-300 system for subsequent arsenic removal, whose effectiveness was evaluated based on its ability
to remove arsenic to below the new arsenic maximum contaminant level (MCL) of 10 |og/L. This project
also (1) evaluated the reliability of the treatment system for use at small water facilities, (2) determined
the required system operation and maintenance (O&M) and operator skill levels, (3) characterized process
residuals generated by the treatment process, and (4) determined the capital and O&M cost of the
technology. The types of data collected included system operation, water quality (both across the
treatment train and in the distribution system), process residuals, and capital and O&M cost.
The 250 gal/min (gpm) treatment system consisted of an AERALATER® pretreatment unit and an arsenic
package unit (APU)-300 arsenic removal unit. Used for iron removal, the 11-ft x 26-ft carbon-steel
AERALATER® package unit was composed of an aeration tower, a detention tank, and a four-cell gravity
filter in one stacked circular configuration. The effluent from the gravity filter was subsequently polished
with AD-33 media, an iron-based adsorptive media developed by Bayer AG for arsenic removal. The
APU-300 system consisted of two skid-mounted 63-in x 86-in fiberglass vessels configured in parallel.
Each vessel contained 64 ft3 of pelletized AD-33 media supported by gravel underbedding.
The treatment system began routine operation on February 2, 2006. Through the end of the performance
evaluation study on February 28, 2007, the system treated approximately 20,441,000 gal of water with an
average run time of 4.7 hr/day. The average daily demand was 52,418 gal. Water to the treatment system
was supplied by two wells (Wells No. 3 and 4), each operating at an average flowrate of 191 and 184
gpm, respectively, on an alternating basis. These reduced flowrates resulted in longer detention times (45
to 46 min versus the design value of 34 min) within the AERALATER® detention tank and lower
hydraulic loading rates (2.0 to 1.9 gpm/ft2 versus the design value of 2.6 gpm/ft2) to the gravity filter. The
corresponding flowrates measured through the APU-300 system also resulted in longer empty bed contact
time (EBCT) (5.4 min compared to the design value of 3.8 min) in each vessel. No significant
operational or mechanical issues were experienced during the 1-year performance evaluation study
period. However, 4 months after the end of the performance evaluation study, the operator reported
biofouling of the AERALATER® filter that necessitated the use of chlorine to clean the filter media and
re-injection of a previously selected, but later abandoned oxidant (sodium permanganate [NaMnO4]), to
oxidize soluble As(III).
The source water contained 31.4 to 56.4 |og/L of total arsenic, with soluble As(III) at an average
concentration of 35.3 |og/L as the predominant species. To oxidize soluble As(III), NaMnO4 was selected
due to the presence of elevated total organic carbon (TOC) (6.4 mg/L on average) and ammonia levels
(1.6 mg/L [as N] on average) in raw water. Based on February 2, 2006, data, 90% of soluble As(III) was
oxidized to soluble As(V) when NaMnO4 was added prior to aeration. Soluble As(V) was then adsorbed
onto and/or co-precipitated with iron solids, resulting in 57% soluble As(V) removal. The arsenic-laden
iron solids were effectively removed by the gravity filter, achieving approximately 60% total arsenic and
100% total iron removal. The remaining arsenic was present mostly as soluble As(V) at 26.4 |o,g/L (on
average), which was subsequently removed by AD-33 media. The elevated soluble As(V) in the gravity
filter effluent was most likely caused by the relatively high levels of pH (7.9 on average), competing
anions (such as phosphorous [301 |o,g/L (as P) on average] and silica [25.1 mg/L (as SiO2) on average]),
and TOC in source water.
IV
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After one week of operation, NaMnO4 addition was inadvertently discontinued due to problems with the
chemical feed pump. It was subsequently decided to operate the system without NaMnO4 addition due to
the discovery of microbial-mediated As(III) oxidation processes and elevated manganese levels (e.g.,
127 |og/L on February 2, 2006) in the gravity filter effluent. The elevated manganese concentrations in
the gravity filter effluent were attributed to the formation of colloidal MnO2 in the presence of TOC
(Knocke et al., 1991). Elevated manganese levels have been shown to be detrimental to AD-33 media
based on studies at other EPA demonstration sites, where high manganese loadings were found to coat
and/or foul AD-33 media in the presence of chlorine (Oxenham et al., 2005).
Without NaMnO4 addition, the total arsenic removal rate averaged 34%, and the iron removal rate was
100% across the gravity filter. The oxidation of Fe(II) was accomplished through aeration. It also was
observed that the oxidation of soluble As(III) to soluble As(V) was occurring at a rate of over 94% across
the gravity filter via naturally occurring microbial-mediated processes, with only 1.6 (ig/L of soluble
As(III) in the filter effluent (on average). Nitrification also was observed within the gravity filter, but was
not related to the microbially mediated processes as noted. The soluble As(V) concentration averaged
26.4 |o,g/L after the gravity filter, which is comparable to the vendor's design estimate of 20 to 27 |o,g/L of
arsenic after the gravity filter and before the AD-33 adsorption system. Therefore, the arsenic removal
rate without NaMnO4 was within the vendor's design basis of 30% to 50% across the gravity filter.
With or without the addition of NaMnO4, soluble As(V) remained above 10 |o,g/L in the gravity filter
effluent, thus requiring further treatment with the APU-300 unit. The arsenic concentration in the APU-
300 system effluent was below 10 (ig/L during the 1-year performance study. Based on compliance
samples collected after the end of the study and average daily production values, the AD-33 media run
length was estimated at 25,300 bed volumes (BV) of water, which was only 31% of the vendor-projected
APU-300 capacity of 82,500 BV. As discussed above, the total arsenic-removal efficiency of the gravity
filter was reduced from approximately 60% to 34% after discontinuing NaMnO4 addition, which shifted
the burden of arsenic removal from the gravity filter to the downstream adsorption vessels. However, as
mentioned above, the average concentration of soluble As(V) (26.4 |og/L) in the gravity filter effluent
(without NaMnO4 addition) was close to the design basis of 20 to 27 |o,g/L in the influent to the APU-300
system. Therefore, the reason for the discrepancy in run length was attributed, in part, to competition
from elevated total phosphorous in the source water, which was not accounted for in the vendor's run-
length estimate. Biofouling in the adsorption vessels also might have contributed to the short run length.
AERALATER® backwash was manually initiated weekly by the operator. The APU-300 system was
backwashed manually four times during the 1-year performance evaluation study. Approximately
406,400 gal of wastewater, or 2% of the quantity of the treated water, was generated during the 1-year
performance study from the AERALATER®. The AERALATER® backwash wastewater contained, on
average, 87 mg/L of total suspended solids (TSS), 38 mg/L of iron, 343 |o,g/L of arsenic, and 57 |o,g/L of
manganase, with the majority existing as particulate. The average amount of solids discharged per
backwash cycle was approximately 5.5 Ib, which was composed of 2.4 Ib of elemental iron, 0.002 Ib of
elemental manganese, and 0.02 Ib of elemental arsenic. In addition, 25,415 gal of wastewater were
generated by the APU-300 unit, or 0.1% of the quantity of treated water.
Comparison of the distribution system sampling results before and after system startup showed a
significant decrease in arsenic concentration from an average of 31.2 to 6.1 (ig/L. The arsenic
concentrations in the distribution system, however, were generally higher than those following the AD-33
adsorption vessels. Desorption and resuspension of arsenic that previously accumulated on the
distribution pipe surfaces was the probable reason for the higher concentration in the distribution system.
Iron concentration in the distribution system was significantly reduced, while manganese levels appeared
to remain the same after system startup. Both lead and copper concentrations in the distribution system
were significantly lower than their action levels.
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The capital investment for the system was $367,838: consisting of $273,873 for equipment, $16,520 for
site engineering, and $77,445 for installation, shakedown, and startup. Using the system's rated capacity
of 250 gpm or 360,000 gal/day (gpd), the capital cost was $1,471 pergpm of design capacity ($1.02/gpd).
This calculation did not include the cost of the building to house the treatment system. The O&M cost
consisted primarily of the media replacement cost, which was estimated by the vendor at $41,370, to
change out the AD-33 media. Media changeout did not occur during the performance evaluation period.
The O&M cost is presented as a function of potential media run length in this report.
VI
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CONTENTS
DISCLAIMER ii
FOREWORD iii
ABSTRACT iv
FIGURES viii
TABLES ix
ABBREVIATIONS AND ACRONYMS x
ACKNOWLEDGMENTS xiii
1.0 INTRODUCTION 1
1.1 Background 1
1.2 Treatment Technologies for Arsenic Removal 2
1.3 Project Objectives 2
2.0 SUMMARY AND CONCLUSIONS 5
3.0 MATERIALS AND METHODS 7
3.1 General Project Approach 7
3.2 System O&M and Cost Data Collection 8
3.3 Sample Collection Procedures and Schedules 9
3.3.1 Source Water 9
3.3.2 Treatment Plant Water 9
3.3.3 Backwash Wastewater 9
3.3.4 Distribution System Water 12
3.3.5 Residual Solids 12
3.4 Sampling Logistics 12
3.4.1 Preparation of Arsenic Speciation Kits 12
3.4.2 Preparation of Sampling Coolers 12
3.4.3 Sample Shipping and Handling 13
3.5 Analytical Procedures 13
4.0 RESULTS AND DISCUSSION 14
4.1 Facility Description 14
4.1.1 Source-Water Quality 17
4.1.2 Treated-Water Quality and Distribution System 19
4.2 Treatment Process Description 19
4.3 Treatment System Installation 26
4.3.1 Permitting 26
4.3.2 Building Construction 26
4.3.3 System Installation, Shakedown, and Startup 26
4.4 System Operation 28
4.4.1 AERALATER® Operations 28
4.4.2 APU-300 Operations 29
4.4.3 Backwash Operations 29
4.4.4 Residual Management 31
4.4.5 Reliability and Simplicity of Operation 31
4.4.5.1 Pre- and Post-Treatment Requirements 31
4.4.5.2 System Automation 32
4.4.5.3 Operator Skill Requirements 32
4.4.5.4 Preventive Maintenance Activities 32
4.4.5.5 Chemical-Handling and Inventory Requirements 32
vii
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4.5 System Performance 33
4.5.1 Treatment Plant 33
4.5.1.1 Arsenic 33
4.5.1.2 Iron 41
4.5.1.3 Manganese 42
4.5.1.4 pH, DO, andORP 43
4.5.1.5 Ammonia and Nitrate 44
4.5.1.6 Other Water Quality Parameters 46
4.5.2 Backwash Wastewater Sampling 46
4.5.3 Distribution System Water Sampling 48
4.6 System Cost 51
4.6.1 Capital Cost 52
4.6.2 Operation and Maintenance Cost 52
5.0 REFERENCES 56
APPENDIX A: OPERATIONAL DATA
APPENDIX B: ANALYTICAL DATA TABLES
FIGURES
Figure 3-1. Process Flow Diagram and Sampling Schedule and Locations 11
Figure 4-1. Wellhead 3 at Stewart, Minnesota 14
Figure 4-2. Wellhead 4 at Stewart, Minnesota 15
Figure 4-3. Existing Chemical Addition Equipment at Stewart, Minnesota 15
Figure 4-4. Existing Chemical Addition and Entry Piping with Flow Totalizer and Pressure
Gauge at Stewart, Minnesota 16
Figure 4-5. A 65,000-gal Water Tower at Stewart, Minnesota 16
Figure 4-6. Schematic of AERALATER® and APU-3 00 Systems at Stewart, Minnesota 20
Figure 4-7. AERALATER® and APU-300 Systems at Stewart, Minnesota 20
Figure 4-8. Schematic of Type II AERALATER® System 24
Figure 4-9. Schematic of APU-300 System 25
Figure 4-10. Building with AERLATER® Tower, Backwash Sump, and Backwash Wastewater
Holding Tanks at Stewart, Minnesota 27
Figure 4-11. Off-Loading and Placement of AERALATER® Unit at Stewart, Minnesota 27
Figure 4-12. Instantaneous Flowrates Through Adsorption Vessels A and B 30
Figure 4-13. Arsenic Speciation Results at Wellhead (IN), After Contact Tank (AC), After
Filtration (AF), and After Vessels A and B Combined (TT) 37
Figure 4-14. Total Arsenic Concentrations vs. Throughput 39
Figure 4-15. Biogeochemical Cycle of Arsenic 41
Figure 4-16. Total Iron Concentrations vs. Bed Volumes 42
Figure 4-17. Total Manganese Concentrations vs. Bed Volumes 43
Figure 4-18. Decreases/Increases in Ammonia/Nitrate Across AERALATER® Filter and AD-33
Adsorption Vessels 45
Figure 4-19. Comparsion of Total Arsenic Concentrations in Distribution System Water and
APU-300 System Effluent 51
Figure 4-20. Media Replacement and O&M Cost for AERALATER® and APU-300 Systems at
Stewart, Minnesota 55
Vlll
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TABLES
Table 1-1. Summary of Rounds 1 and 2 Arsenic-Removal Demonstration Sites 3
Table 3-1. Pre-demonstration and Demonstration Study Activities and Completion Dates 7
Table 3-2. Evaluation Objectives and Supporting Data Collection Activities 8
Table 3-3. Sampling Locations, Schedules and Analyses 10
Table 4-1. City of Stewart, Minnesota, Water Quality Data 18
Table 4-2. Physical and Chemical Properties of AD-33 Media 21
Table 4-3. Design Specifications of Type IIAERALATER® and APU-3 00 Systems 23
Table 4-4. Summary of Treatment System Operation at Stewart, Minnesota 28
Table 4-5. Summary of Backwash Operations at Stewart, Minnesota 30
Table 4-6. Summary of Arsenic, Iron, and Manganese Analytical Results 34
Table 4-7. Summary of Other Water Quality Parameter Measurements 35
Table 4-8. AERALATER® Filter Backwash Wastewater Sampling Results 47
Table 4-9. AERALATER® Filter Backwash Solids Total Metal Results 47
Table 4-10. APU-300 Adsorption Vessels Backwash Wastewater Sampling Results 48
Table 4-11. Distribution System Sampling Results 49
Table 4-12. Capital Investment Cost for Siemens and AdEdge Treatment Systems 53
Table 4-13. O&M Cost for City of Stewart, Minnesota Treatment System 54
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ABBREVIATIONS AND ACRONYMS
AAL American Analytical Laboratories
Al aluminum
AM adsorptive media
APU arsenic package unit
As arsenic
ATS Aquatic Treatment Systems
BET Brunauer, Emmett, and Teller Method
bgs below ground surface
BV bed volume (s)
Ca calcium
CAO chemolithoautotrophic arsenite oxidizer
C/F coagulation/filtration
cfm cubic foot per minute
Cl chlorine
CRF capital recovery factor
Cu copper
DBF disinfection byproducts
DO dissolved oxygen
DOM dissolved organic matter
EBCT empty bed contact time
EPA U.S. Environmental Protection Agency
F fluoride
Fe iron
FedEx Federal Express
GCSP Greene County Southern Plant
GFH granular ferric hydroxide
gpd gallons per day
gpm gallons per minute
gph gallons per hour
FŁAA5 haloacetic acids
FŁAO heterotrophic arsenite oxidizers
HIX hybrid ion exchanger
H2SO4 sulfuric acid
hp horsepower
ICP-MS inductively coupled plasma-mass spectrometry
ID identification
IX ion exchange
kgal kilo gallons
KMnO4 potassium permanganate
LCR (EPA) Lead and Copper Rule
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MCL maximum contaminant level
MEI Magnesium Elektron, Inc.
MDH Minnesota Department of Health
MDL method detection limit
Mg magnesium
jam micrometer
Mn manganese
mV millivolts
Na sodium
NA not applicable
ND not detected
NS not sampled
NSF NSF International
NTU nephelometric turbidity units
O&M operation and maintenance
OIT Oregon Institute of Technology
ORD Office of Research and Development
ORP oxidation-reduction potential
P&ID process and instrumentation diagram
Pb lead
pCi pico curie
psi pounds per square inch
PLC programmable logic controller
PO4 orthophosphate
POE point of entry
POU point of use
PVC polyvinyl chloride
QA quality assurance
QA/QC quality assurance/quality control
QAPP Quality Assurance Project Plan
RO reverse osmosis
RPD relative percent difference
Sb antimony
SDWA Safe Drinking Water Act
SiO2 silica
SMCL secondary maximum contaminant level
SO4 sulfate
STS Severn Trent Services
TCLP Toxicity Characteristic Leaching Procedure
TDH total dynamic head
TDS total dissolved solids
THM trihalomethanes
TOC total organic carbon
TSS total suspended solids
XI
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V vanadium
VOC volatile organic compound
xn
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ACKNOWLEDGMENTS
The authors wish to extend their sincere appreciation to Mr. Michael Richards of the City of Stewart in
Minnesota. Mr. Richards monitored the treatment system and collected samples from the treatment and
distribution systems on a regular schedule throughout this study period. This performance evaluation
would not have been possible without his support and dedication.
xin
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1.0 INTRODUCTION
1.1 Background
The Safe Drinking Water Act (SDWA) mandates that U.S. 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). 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 required 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, onsite 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 Round 1 of this EPA-sponsored demonstration program to provide information on their
water systems. In June 2002, EPA selected 17 of the 115 candidate sites to host the demonstration
studies.
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 it determined
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.
In 2003, EPA initiated Round 2 arsenic technology demonstration projects that were partially funded with
Congressional add-on funding to the EPA budget. In June 2003, EPA selected 32 potential demonstration
sites. The community water system at the City of Stewart in Minnesota was one of those selected.
In September 2003, EPA again solicited proposals from engineering firms and vendors for arsenic-
removal technologies. EPA received 148 technical proposals for the 32 host sites, with each site
receiving from two to eight proposals. In April 2004, EPA convened another technical panel to review
the proposals and provide recommendations to EPA; the number of proposals per site ranged from none
(for two sites) to a maximum of four. Final selection of the treatment technology at sites receiving at least
one proposal was made, again through a joint effort by EPA, the state regulators, and the host site. Since
then, four sites have withdrawn from the demonstration program, reducing the number of sites to 28.
Two technologies were selected for demonstration at the Stewart, MN, facility, including Siemens'
(formerly known as USFilter) Type IIAERALATER® for iron removal, followed by AdEdge
Technologies' AD-33 adsorptive media for arsenic removal.
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As of December 2009, 39 of the 40 systems were operational, and the performance evaluation of 34
systems was completed.
1.2 Treatment Technologies for Arsenic Removal
The technologies selected for the Rounds 1 and 2 demonstration host sites included 25 adsorptive media
(AM) systems (the Oregon Institute of Technology [OIT] site has three AM systems); 13
coagulation/filtration (C/F) systems; two ion exchange (IX) systems; 17 point-of-use (POU) units
(including nine under-the-sink reverse osmosis [RO] units at the Sunset Ranch Development site and
eight AM units at the OIT site); and one system modification. Table 1-1 summarizes the locations,
technologies, vendors, system flowrates, and key source-water-quality parameters (including As, Fe, and
pH) at the 40 demonstration sites. An overview of the technology selection and system design for the 12
Round 1 demonstration sites and the associated capital costs is provided in two EPA reports (Wang et al.,
2004; Chen et al., 2004), which are posted on the EPA Web site at
http://www.epa.gov/ORD/NRMRL/wswrd/dw/arsenic/index.html.
1.3 Project Objectives
The objective of the arsenic demonstration program is to conduct 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
• Characterize process residuals produced by the technologies
• Determine the capital and O&M cost of the technologies.
This report summarizes the performance of the Siemens' Type IIAERALATER® and AdEdge Arsenic
Package Unit (APU)-300 systems at Stewart, MN, during February 2, 2006, through February 28, 2007.
The types of data collected included system operation, water quality (both across the treatment train and
in the distribution system), residuals, and capital and O&M cost.
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Table 1-1. Summary of Rounds 1 and 2 Arsenic-Removal Demonstration Sites
Demonstration
Location
Site Name
Technology (Media)
Vendor
Design
Flow rate
(gpm)
Source Water Quality
As
(MS/L)
Fe
(MS/L)
PH
(S.U.)
Northeast/Ohio
Wales, ME
Bow,NH
Goffstown, NH
Rollinsford, NH
Dummerston, VT
Felton, DE
Stevensville, MD
Houghton, NY(d)
Newark, OH
Springfield, OH
Springbrook Mobile Home Park
White Rock Water Company
Orchard Highlands Subdivision
Rollinsford Water and Sewer District
Charette Mobile Home Park
Town of Felton
Queen Anne's County
Town of Caneadea
Buckeye Lake Head Start Building
Chateau Estates Mobile Home Park
AM (A/I Complex)
AM(G2)
AM(E33)
AM(E33)
AM (A/I Complex)
C/F (Macrolite)
AM(E33)
C/F (Macrolite)
AM (ARM 200)
AM(E33)
ATS
ADI
AdEdge
AdEdge
ATS
Kinetico
STS
Kinetico
Kinetico
AdEdge
14
70(b)
10
100
22
375
300
550
10
250(e)
38W
39
33
36W
30
30W
19(a)
27W
15W
25W
<25
<25
<25
46
<25
48
270(c)
l,806(c)
1,312W
1,615W
8.6
7.7
6.9
8.2
7.9
8.2
7.3
7.6
7.6
7.3
Great Lakes/Interior Plains
Brown City, MI
Pentwater, MI
Sandusky, MI
Delavan, WI
Greenville, WI
Climax, MN
Sabin, MN
Sauk Centre, MN
Stewart, MN
Lidgerwood, ND
City of Brown City
Village of Pentwater
City of Sandusky
Vintage on the Ponds
Town of Greenville
City of Climax
City of Sabin
Big Sauk Lake Mobile Home Park
City of Stewart
City of Lidgerwood
AM(E33)
C/F (Macrolite)
C/F (Aeralater)
C/F (Macrolite)
C/F (Macrolite)
C/F (Macrolite)
C/F (Macrolite)
C/F (Macrolite)
C/F&AM(E33)
Process Modification
STS
Kinetico
Siemens
Kinetico
Kinetico
Kinetico
Kinetico
Kinetico
AdEdge
Kinetico
640
400
340W
40
375
140
250
20
250
250
14w
13W
16W
20W
17
39W
34
25W
42W
146W
127(c)
466W
l,387(c)
l,499(c)
7827(c)
546(c)
l,470(c)
3,078(c)
1,344W
1,325W
7.3
6.9
6.9
7.5
7.3
7.4
7.3
7.1
7.7
7.2
Midwest/Southwest
Amaudville, LA
Alvin, TX
Bruni, TX
Wellman, TX
Anthony, NM
Nambe Pueblo, NM
Taos, NM
Rimrock, AZ
Tohono O'odham
Nation, AZ
Valley Vista, AZ
United Water Systems
Oak Manor Municipal Utility District
Webb Consolidated Independent School
District
City of Wellman
Desert Sands Mutual Domestic Water
Consumers Association
Nambe Pueblo Tribe
Town of Taos
Arizona Water Company
Tohono O'odham Utility Authority
Arizona Water Company
C/F (Macrolite)
AM(E33)
AM(E33)
AM(E33)
AM(E33)
AM(E33)
AM(E33)
AM(E33)
AM(E33)
AM (AAFS50/ARM 200)
Kinetico
STS
AdEdge
AdEdge
STS
AdEdge
STS
AdEdge
AdEdge
Kinetico
770(e)
150
40
100
320
145
450
90(b)
50
37
35W
19w
56(a)
45
23(a)
33
14
50
32
41
2,068(c)
95
<25
<25
39
<25
59
170
<25
<25
7.0
7.8
8.0
7.7
7.7
8.5
9.5
7.2
8.2
7.8
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Table 1-1. Summary of Rounds 1 and 2 Arsenic-Removal Demonstration Sites (Continued)
Demonstration
Location
Site Name
Technology (Media)
Vendor
Design
Flow rate
(gpm)
Source Water Quality
As
(ug/L)
Fe
(Mg/L)
PH
(S.U.)
Far West
Three Forks, MT
Fruitland, ID
Homedale, ID
Okanogan, WA
Klamath Falls, OR
Vale, OR
Reno, NV
Susanville, CA
Lake Isabella, CA
Tehachapi, CA
City of Three Forks
City of Fruitland
Sunset Ranch Development
City of Okanogan
Oregon Institute of Technology
City of Vale
South Truckee Meadows General
Improvement District
Richmond School District
Upper Bodfish Well Cffi-A
Golden Hills Community Service District
C/F (Macrolite)
IX (A300E)
POU RO(1)
C/F (Electromedia-I)
POE AM (Adsorbsia/ARM 200/ArsenXnp)
and POU AM (ARM 200)(g)
IX (Arsenex II)
AM (GFH/Kemiron)
AM (A/I Complex)
AM(HIX)
AM (Isolux)
Kinetico
Kinetico
Kinetico
Filtronics
Kinetico
Kinetico
Siemens
ATS
VEETech
MEI
250
250
75gpd
750
60/60/30
525
350
12
50
150
64
44
52
18
33
17
39
37W
35
15
<25
<25
134
69w
<25
<25
<25
125
125
<25
7.5
7.4
7.5
8.0
7.9
7.5
7.4
7.5
7.5
6.9
AM = adsorptive media process; C/F = coagulation/filtration; HTX = hybrid ion exchanger; IX = ion exchange process; RO = reverse osmosis
ATS = Aquatic Treatment Systems; MEI = Magnesium Elektron, Inc.; STS = Severn Trent Services.
(a) Arsenic existing mostly as As(III).
(b) Design flowrate reduced by 50% due to system reconfiguration from parallel to series operation.
(c) Iron existing mostly as Fe(II).
(d) Withdrew from program in 2007. Selected originally to replace Village of Lyman, NE site, which withdrew from program in June 2006.
(e) Facilities upgraded systems in Springfield, OH, from 150 to 250 gpm; Sandusky, MI, from 210 to 340 gpm; and Amaudville, LA, from 385 to 770 gpm.
(f) Including nine residential units.
(g) Including eight under-the-sink units.
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2.0 SUMMARY AND CONCLUSIONS
The Siemens AERALATER® and AdEdge Technologies AD-33 APU-300 units were installed and have
operated at Stewart, MN, since February 2, 2006. Based on the information collected during the 1-year
performance evaluation study from February 2, 2006 to February 28, 2007, the following conclusions
were drawn relating to the overall objectives of the treatment technology demonstration study.
Performance of the arsenic removal technology:
• Aeration was effective in oxidizing soluble iron, converting 100% of it to iron solids.
However, aeration was only minimally effective in oxidizing soluble As(III), converting
25.8% (on average) of soluble As(III) to soluble As(V) and particulate arsenic.
• NaMnO4was effective in oxidizing As(III), converting over 90% of soluble As(III) to soluble
As(V) and particulate arsenic. Of the As(V) in the contact section of the AERALATER®,
only 57% became attached to iron solids formed during the preoxidation step, presumably via
adsorption and co-precipitation. The relatively low As(V) removal rate was most likely the
result of the relatively elevated pH (i.e., 7.9), competing anions (such as 301 (ig/L of total
phosphorous [as P] and 25.1 mg/L of Si [as SiO2]), and total organic carbon [TOC] (6.4
mg/L) in source water.
• NaMnO4 addition resulted in elevated manganese levels in the gravity filter effluent, which
were attributed to colloidal MnO2 formation in the presence of high TOC levels.
• Upon discontinuation of NaMnO4 addition, naturally occurring microbial-mediated pathways
were thought to be responsible for the oxidation of over 94% of soluble As(III) within the
AERALATER® filter, leaving only 1.6 (ig/L of soluble As(III) in the filter effluent.
Nitrification also occurred within the gravity filter and AD-33 adsorption vessels. Oxygen,
instead of nitrate, was believed to be the electron acceptor for the microbial-mediated As(III)
oxidation processes observed.
• The AERALATER® filter was highly effective in removing particulate matter. Without
NaMnO4 addition, 34% of total arsenic was removed, compared to 60% removed with
NaMnO4 addition. Aeration alone in the AERALATER® system was sufficient to
accomplish complete iron removal. No particulate iron breakthrough was observed from the
AERALATER® filter, suggesting adequate filter backwash frequency.
• AD-33 media effectively removed arsenic to below 10 (ig/L during the 1-year performance
study. Based on compliance samples collected after the end of the study and average daily
production values, the media run length was estimated at 25,300 bed volumes (BV), which
was only 31% of the vendor-projected run length of 82,500 BV. Competition from
phosphorous in source water might have contributed, in part, to the short run length.
• Due to biofouling in the gravity filter and APU-300 system, the city used chlorine after the
demonstration study to restore the hydraulic capacity of the gravity filter; NaMnO4 addition
was re-started, along with a blending scheme to send only a portion of the gravity-filter-
treated water to the APU-300 system.
• The treatment system improved the water quality in the distribution system with considerable
decreases in arsenic (from 31.2 to 6.1 |og/L) and iron (from 376 to 112 |o,g/L) concentrations.
However, arsenic concentrations were higher in the distribution system than in the treatment
plant effluent, suggesting desorption and resuspension of arsenic from pipe surfaces.
Required system operation and maintenance and operator's skill levels:
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• Daily operation of the system did not require additional skills beyond those necessary to
operate existing water-supply equipment. The daily demand on the operator was only 10
min/day for routine operations.
• Because the system was backwashed only once a week, manual backwash was acceptable to
the plant operator. The time required was 31 min per backwash event.
• Biofouling, observed 4 months after the end of the study period, required using chlorine to
clean up the gravity filter. NaMnO4 addition alone could not control biofouling and some
periodic chlorination would be required. The high TOC and ammonia levels at the site
limited the use of chlorine on a continual basis due to the potential for disinfection by-
products (DBF) formation.
Characteristics of residuals produced by the technology:
• Residuals produced by operation of the treatment system included only backwash wastewater
from the AERALATER® gravity filter and the AD-33 adsorption vessels. The media was not
replaced during the 1-year performance evaluation study.
• The amount of wastewater produced was equivalent to about 2.1% of the amount of water
treated (406,400 gal or 2% from the AERALATER® and 25,415 gal or 0.1% from the APU-
300 unit).
• The amount of solids produced per filter backwash cycle was 5.5 Ib, which included 2.4 Ib of
elemental iron, 0.02 Ib of elemental arsenic, and 0.002 Ib of elemental manganese.
Cost-effectiveness of the technology:
• The capital investment for the system was $367,838: $273,873 for equipment, $16,520 for
site engineering, and $77,445 for installation, shakedown, and startup. The building cost
incurred by the City of Stewart was not included in the capital investment cost.
• Using the system's rated capacity of 250 gpm, or 360,000 gpd, the capital cost was
$l,471/gpm ($1.02/gpd) of design capacity.
• Although not incurred during the 1-year performance study, the AD-33 media
replacement cost would be the majority of the O&M cost for the system and was
estimated to be $41,370.
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3.0 MATERIALS AND METHODS
3.1
General Project Approach
Table 3-1 summarizes the pre-demonstration and demonstration study activities and completion dates.
Following the pre-demonstration activities, the performance evaluation study of the treatment system
began on February 2, 2006. Table 3-2 summarizes the types of data collected and considered as part of
the technology evaluation process. The overall system performance was evaluated based on its ability to
consistently remove arsenic to below the target MCL of 10 |o,g/L through the collection of water samples
across the treatment train. The reliability of the system was evaluated by tracking the unscheduled system
downtime and the frequency and extent of repair and replacement. The plant operator recorded
unscheduled downtime and repair information on a Repair and Maintenance Log Sheet.
Table 3-1. Pre-demonstration and Demonstration Study Activities
and Completion Dates
Activity
Introductory Meeting Held
Draft Letter of Understanding Issued
Final Letter of Understanding Issued
Request for Quotation Issued to Vendor
Vendor Quotation Received
Purchase Order Established
Letter Report Issued
Engineering Package Submitted to MDH
System Permit Granted by MDH
Building Construction Permit Granted
Building Construction Begun
APU-300 Unit Shipped/ Arrived
AERALATER® Shipped/Arrived
System Installation/Shakedown Completed
Study Plan Issued
Performance Evaluation Begun
Building Construction Completed
Performance Evaluation Ended
Date
08/30/04
11/18/04
12/10/04
01/21/05
03/15/05
03/29/05
03/09/05
03/21/05
06/20/05
06/13/05
07/01/05
09/06/05
09/16/05
01/18/06
01/24/06
02/02/06
02/09/06
02/28/07
MDH = Minnesota Department of Health.
The O&M and operator skill requirements 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 system staffing requirements were recorded on an Operator Labor Hour Log Sheet.
The quantity of aqueous and solid residuals generated was estimated by tracking the volume of backwash
wastewater produced during each backwash cycle and the need to replace the media upon arsenic
breakthrough. Backwash wastewater was sampled and analyzed for chemical characteristics.
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Table 3-2. Evaluation Objectives and Supporting Data Collection Activities
Evaluation Objective
Performance
Reliability
System O&M and Operator
Skill Requirements
Residual Management
Cost-Effectiveness
Data Collection
-Ability to consistently meet 10 (og/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 preventative maintenance including number, frequency,
and complexity of tasks
-Chemical handling and inventory requirements
-General knowledge needed for relevant chemical processes and health and
safety practices
-Quantity and characteristics of aqueous and solid residuals generated by
system operation
-Capital cost for equipment, engineering, and installation
-O&M cost for chemical usage, electricity consumption, and labor
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 tracking the capital
cost for the equipment, engineering, and installation, as well as the O&M cost for media replacement and
disposal, chemical supply, electricity use, and labor.
3.2
System O&M and Cost Data Collection
The plant operator performed daily, weekly, and monthly system O&M and data collection following the
instructions provided by the vendor and Battelle. On a daily basis (including Saturdays and Sundays), the
plant operator recorded system operational data, such as pressure, flowrate, totalizer, and hour meter
readings on a Daily System Operation Log Sheet and conducted visual inspections to ensure normal
system operations. If any problem occurred, the plant operator contacted the Battelle Study Lead, who
determined if the vendor needed to be contacted for troubleshooting. The plant operator recorded all
relevant information, including the problems encountered, course of action taken, materials and supplies
used, and associated cost and labor incurred, on a Repair and Maintenance Log Sheet. On a weekly basis,
the plant operator measured several water quality parameters onsite, including temperature, pH, dissolved
oxygen (DO), and oxidation-reduction potential (ORP), and recorded the data on a Weekly Onsite Water
Quality Parameters Log Sheet. Weekly backwash data also were recorded on a Backwash Log Sheet.
The capital cost for the arsenic-removal system consisted of the expenditure for equipment, site
engineering, and system installation. The O&M cost consisted of the expenditure for media replacement,
electricity consumption, and labor. Electricity consumption was determined from utility bills. Labor for
various activities, such as routine system O&M, troubleshooting and repairs, and demonstration-related
work, were tracked using an Operator Labor Hour Log Sheet. Routine system O&M included activities
such as completing field logs, 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 the cost analysis.
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3.3 Sample Collection Procedures and Schedules
To evaluate system performance, samples were collected from the wellhead, across the treatment plant,
during backwash of Type II AERALATER® and AD-33 adsorption vessels, and from the distribution
system. Table 3-3 provides the sampling schedules and analytes measured during each sampling event.
Figure 3-1 presents a flow diagram of the treatment system along with the analytes and schedules at each
sampling location. Specific sampling 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, 2004). Appendix A of the QAPP describes the procedure for arsenic
speciation.
3.3.1 Source Water. During the initial visit to the site, source-water samples were collected and
speciated using an arsenic speciation kit as described in Section 3.4.1. The sample tap was flushed for
several minutes before sampling; special care was taken to avoid agitation, which might cause unwanted
oxidation. Table 3-3 lists analytes for the source-water samples.
3.3.2 Treatment Plant Water. During the system performance evaluation study, the plant
operator collected samples weekly, on a 4-week cycle, for onsite and offsite analyses. For the first week
of each 4-week cycle, samples taken at the wellhead (IN), after the contact tank (AC), after
AERALATOR® gravity filter (AF), and at the combined effluent of Vessels A and B (TT), were speciated
onsite and analyzed for the analytes listed in Table 3-3. For the next 3 weeks, samples were collected at
IN, AC, AF, and after Vessels A (TA) and B (TB) and were analyzed for the analytes listed in Table 3-3.
Over the 1-year demonstration study, two changes were made to the sampling schedules as follows:
• Before April 25, 2006, the monthly speciation sample at the TT location was
collected from either the TA or TB sampling tap due to absence of a combined
effluent sample tap at the time.
• After December 18, 2006, the sampling frequency was reduced to monthly speciation
sampling at IN, AC, AF, and TT locations through the end of the performance evaluation
study.
3.3.3 Backwash Wastewater. AERALATER® backwash wastewater samples were collected
monthly by the plant operator. Grab samples were collected monthly from March 1, 2006, to August 23,
2006. Because of the absence of a sampling tap on the backwash wastewater discharge line, grab samples
were taken directly from the backwash wastewater discharge sump. One aliquot was collected as is and
the other filtered onsite with 0.45-(im disc filters. Since September 20, 2006, composite samples were
collected monthly, using a revised procedure to allow collection of more representative samples during
backwash. A 1/40-horsepower (hp) recirculation submersible water pump was used to collect a
slipstream of water from the backwash wastewater sump to a 50-gal container over the duration of
backwash for filter cells 1 and 2, respectively. At the end of each backwash cycle, the content in the
container was mixed thoroughly, and composite samples were collected and filtered onsite with 0.45-(im
disc filters. Table 3-3 lists analytes for the backwash wastewater samples.
The APU-300 system was backwashed manually four times during the performance evaluation study
period, with one set of composite backwash wastewater samples collected. Tubing connected to the tap
on the discharge line of each adsorption vessel directed a portion of backwash wastewater from each
vessel at about 1 gpm into a clean, 32-gal container throughout the entire backwash. After the content in
the container was thoroughly mixed, composite samples were collected and/or filtered onsite with 0.45-
(im disc filters. Table 3-3 lists analytes for the adsorption vessels backwash samples.
-------
Table 3-3. Sampling Locations, Schedules, and Analyses
Sample Type
Source Water
Treatment Plant
Water
AERALATER®
Filter
Backwash
Wastewater
AERALATER®
Filter
Backwash
Solids
APU-300
Backwash
Wastewater
Distribution
Water
Sample
Locations'3'
IN
IN, AC,
AF, TA,
andTB
IN, AC,
AF, and TT
At
backwash
discharge
sump
At
backwash
discharge
sump
At
backwash
discharge
line
Three non-
LCR
residences
No. of
Samples
1
5
4
2
2
2
3
Frequency
Once
(during
initial site
visit)
Weekly
Monthly
Monthly
Once
Once
Monthly
Analytes
Onsite: pH, temperature,
DO, and ORP
Off site:
As (total and soluble),
As(III), As(V),
Fe (total and soluble),
Mn (total and soluble),
U (total and soluble),
V (total and soluble),
Na, Ca, Mg, Cl, F, NO3,
NO2, NH3, SO4, SiO2, PO4,
Ra-226, Ra-228, TDS,
TOC, alkalinity, and
turbidity
Onsite: pH, temperature,
DO, and ORP
Offsite: As (total),
Fe (total), Mn (total),
P (total), SiO2, alkalinity,
and turbidity
Same as weekly analytes
shown above plus the
following:
Offsite: As (soluble),
As(III), As(V), Fe (soluble),
Mn (soluble), Ca, Mg, F,
NO3, NH3, SO4, and TOC
As (total and soluble),
Fe (total and soluble),
Mn (total and soluble),
pH, TDS, and TSS
TCLP metals and total Al,
As, Ba, Ca, Cd, Cu, Fe, Mg,
Mn, Ni, P, Pb, Sb, Si, V,
andZn
As (total and soluble),
Fe (total and soluble),
Mn (total and soluble),
pH, TDS, and TSS
Total As, Fe, Mn, Cu, and
Pb, pH, and alkalinity
Sampling
Date
08/30/04
Appendix B
Appendix Btb)
Table 4-8
02/28/07
01/17/07
Table 4-1 lw
(a) Abbreviation corresponding to sample locations in Figure 3-1: IN = at wellhead; AC = after contact
tank; AF = after gravity filter; TA = after Vessel A; TB = after Vessel B; TT = after Vessels A and B
combined; and BW = at backwash wastewater discharge line.
(b) Sampling events before 04/25/06 were taken from TA or TB tap due to the absence of combined
effluent sample tap.
(c) Four sampling events were performed before system startup.
LCR = Lead and Copper Rule; TCLP = toxicity characteristic leaching procedure
10
-------
Monthly
pHW, temperature^, DOW, ORP(a),
As (total and soluble), As (III),
As (V), Fe (total and soluble),
Mn (total and soluble), Ca, Mg, F,
NO3, SO4, SiO2, P (total), NH3,
TOC, turbidity, alkalinity
HW, temperature^, DO^, ORP^,
As (total and soluble), As (III),
As (V), Fe (total and soluble),
Mn (total and soluble), Ca, Mg,
F, NO3, SO4, SiO2, P (total), NH3,
TOC, turbidity, alkalinity
HW, temperature^, DO^, ORP^,
As (total and soluble), As (III),
As (V), Fe (total and soluble),
Mn (total and soluble), Ca, Mg,
F, NO3, SO4, SiO2, P (total), NH3,
TOC, turbidity, alkalinity
pH, TDS, TSS,
As (total and soluble),
Fe (total and soluble),
Mn (total and soluble)
pH, TDS, TSS,
As (total and soluble),
Fe (total and soluble),
Mn (total and soluble)
HW, temperature^, DO
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3.3.4 Distribution System Water. Samples were collected from the distribution system to
determine the impact of the arsenic treatment system on its water chemistry, specifically, the arsenic,
lead, and copper levels. Prior to system startup from February to May 2005, four sets of baseline
distribution water samples were collected from three residences within the distribution system. Following
system startup, distribution system sampling continued monthly at the same three locations.
The distribution system water samples were taken following an instruction sheet developed by Battelle
according to the Lead and Copper Rule Reporting Guidance for Public Water Systems (EPA, 2002).
First-draw samples were collected from cold-water faucets that had not been used for at least 6 hours to
ensure that stagnant water was sampled. The sampler recorded the date and time of last water use before
sampling, as well as the date and time of sample collection for calculation of the stagnation time. The
samples were analyzed for the analytes listed in Table 3-3. Arsenic speciation was not performed on the
distribution water samples.
3.3.5 Residual Solids. Residual solids included backwash solids and spent-media samples.
AERALATER® backwash solids samples were collected once on February 28, 2007, after the solids
settled in the 32-gal backwash containers and the supernatant carefully decanted. The samples were air-
dried, acid-digested, and analyzed for Al, As, Ba, Ca, Cd, Cu, Fe, Mg, Mn, Ni, P, Pb, Sb, Si, V, and Zn.
No backwash solids samples were collected during the backwash of the APU-300 unit, since the unit was
only backwashed four times during the 1-year performance evaluation study. Because the adsorption
media was not changed out during the performance evaluation study, no media samples were collected
and analyzed.
3.4 Sampling Logistics
All sampling logistics, including arsenic speciation kits preparation, sample cooler preparation, and
sampling shipping and handling, are discussed below.
3.4.1 Preparation of Arsenic Speciation Kits. The arsenic field speciation method uses 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, 2004).
3.4.2 Preparation of Sample 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, 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, the 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
labeled bottles for each sampling location were placed separately in a Ziplock® bag (each corresponding
to a specific sample location) and packed in the cooler. When needed, the sample cooler also included
bottles for the distribution system sampling.
In addition, all sampling- and shipping-related materials, such as disposable gloves, sampling instructions,
chain-of-custody forms, pre-paid/pre-addressed FedEx air bills, and bubble wrap, were placed in each
cooler. The chain-of-custody forms and airbills were completed except for the operator's signature and
the sample dates and times. After preparation, sample coolers were sent to the site via FedEx for the
following week's sampling event.
12
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3.4.3 Sample Shipping and Handling. After sample collection, samples for offsite analyses were
packed carefully in the original coolers with wet ice and shipped to Battelle. Upon receipt, the sample
custodian checked sample IDs against the chain-of-custody forms and verified that all samples indicated
on the forms were included and intact. The Battelle Study Lead addressed discrepancies noted by the
sample custodian with the plant operator. The shipment and receipt of all coolers by Battelle were
recorded on a cooler tracking log.
Samples for metal analyses were stored and analyzed at Battelie's inductively coupled plasma-mass
spectrometry (ICP-MS) laboratory. Samples for other water quality parameters 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 to Battelle for this
demonstration study. 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
The analytical procedures described in Section 4.0 of the EPA-endorsed QAPP (Battelle, 2003) were
followed by Battelle 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 (20% relative percent difference [RPD], 80 to 120% percent recovery, and 80% completeness). The
QA data associated with each analyte will be presented and evaluated in a QA/QC Summary Report to be
prepared under separate cover upon completion of the Arsenic Demonstration Project.
Field measurements of pH, temperature, DO, and ORP were conducted by the plant operator using a
VWR Symphony SP90M5 handheld multimeter, 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, plastic beaker and placed the SP90M5 probe in the beaker until a
stable value was obtained.
13
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4.0 RESULTS AND DISCUSSION
4.1
Facility Description
The water treatment system at Stewart, MN, supplies drinking water to approximately 600 community
members. The water source is groundwater from two wells (Wells No. 3 and 4). Wellheads 3 and 4 are
shown in Figures 4-1 and 4-2, respectively. The static water level of the wells ranges from 20 to 30 ft
below ground surface (bgs). Each well is 8 in in diameter and extends to a depth of approximately 370 ft
bgs. Well No. 3 has a 50-ft screen length and is equipped with a 20-hp submersible pump with a capacity
of approximately 350 gpm. Well No. 4 has a 52-ft screen length and a 15-hp submersible pump with a
capacity of approximately 275 gpm. Prior to the performance evaluation study, the average daily demand
was 52,420 gpd. Use of these two wells was alternated automatically based on the water tower level.
Typically, each well ran for about 12,000 to 15,000 gal per cycle.
The pre-existing treatment consisted of chlorination, fluoridation, and polyphosphate addition.
Chlorination was accomplished with a gas chlorine feed system to provide chlorine residuals in the
distribution system. The target residual level was 1.1 mg/L for total chlorine (as C12). The water also was
fluoridated to a target level of 1.3 mg/L. Blended polyphosphates were added for iron sequestration and
corrosion control. Figure 4-3 shows the chemical feed pumps and associated tanks within the pump
house. Figure 4-4 shows the entry piping from Wells No. 3 and 4 and the tubing from the chemical feed
pumps. As described in Section 4-2, the pre-existing equipment shown in Figures 4-3 and 4-4 was
replaced with new equipment of similar sizes as part of the pre- and post-treatment. The treated water
was stored in a nearby 65,000-gal water tower, as shown in Figure 4-5.
Figure 4-1. Wellhead 3 at Stewart, Minnesota (near orange flag in center of photo)
14
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Figure 4-2. Wellhead 4 at Stewart, Minnesota (in front of small brown shed)
Figure 4-3. Existing Chemical Addition Equipment at Stewart, Minnesota
15
-------
Figure 4-4. Existing Chemical Addition and Entry Piping with Flow Totalizer and
Pressure Gauge at Stewart, Minnesota
Figure 4-5. A 65,000-gal Water Tower at Stewart, Minnesota
16
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4.1.1 Source-Water Quality. Battelle collected source-water samples from Well No. 3 on August
30, 2004 for detailed water quality characterization; Table 3-3 shows the analytes of interest. In addition,
pH, temperature, DO, and ORP were measured onsite using a VWR Symphony SP90M5 handheld
multimeter. The source water also was filtered for soluble arsenic, iron, manganese, uranium, and
vanadium and speciated for As(III) and As(V) using the field speciation method modified by Battelle
from Edwards, et al. (1998). Table 4-1 presents the analytical results from the source-water sampling
event and compares them to historic data taken by the facility.
The proposed treatment train for the City of Stewart included oxidation with potassium permanganate
(KMnO4), iron removal using gravity filtration, and arsenic adsorption with AD-33 media. Several
factors were anticipated to play a role in the pretreatment process for iron removal, including natural iron
concentration, pH, turbidity, natural organic matter, ammonia, anions, and cations. Factors that may
affect arsenic removal via adsorption include arsenic concentration, arsenic speciation, pH, and other
competing anions.
Arsenic. Total arsenic concentrations in source water ranged from 39.0 to 41.7 |o,g/L. Based on August
30, 2004, sampling results from Well No. 3, out of 41.7 |o,g/L of total arsenic, 31.9 |o,g/L existed as soluble
As(III), 1.0 |o,g/L as soluble As(V), and 8.8 |o,g/L as particulate As. Therefore, soluble As(III) was the
predominating species (about 76%) in groundwater. The proposed treatment process was to use KMnO4,
as originally designed, but was switched to NaMnO4 just before system startup by the city in order to
oxidize soluble As(III) to soluble As(V) prior to iron removal and AD-33 adsorption. Oxidant addition
was discontinued after the discovery of a naturally occurring oxidation process developed within the
AERALATER® filter (see detailed discussion in Section 4.5.1.1). Upon oxidation, soluble As(V) was
removed via adsorption onto and/or co-precipitation with iron solids during the iron-removal pretreatment
step. The remaining As(V) was then removed via adsorption onto the AD-33 media.
Iron and Manganese. In general, adsorptive media technologies are best suited to source water with
relatively low iron levels (i.e., less than 300 |o,g/L, which is the secondary maximum contaminant level
[SMCL] for iron). Above 300 |o,g/L, taste, odor, and color problems can occur in treated water, along
with an increased potential for fouling of the adsorption system. The proposed treatment process at
Stewart, MN, relied on aeration and gravity filtration to remove elevated levels of iron in source water.
This iron removal process also resulted in the removal of some As(V) in the water. Iron concentrations in
source water ranged from 1,344 to 1,400 |o,g/L, which existed almost entirely as soluble iron. Total
manganese in source water ranged from 24 to 27 |og/L, which was below the SMCL of 50 |o,g/L.
pH. pH values of source water ranged from 7.7 to 7.8, which were near the upper end of the target range
of 6.0 to 8.0 for optimal arsenic adsorption onto the AD-33 media.
TOC and Ammonia. The source water contained elevated levels of TOC (ranging from 6.8 to 7.2 mg/L)
and ammonia (at 1.7 mg/L). To avoid the formation of DBFs and high chlorine consumption, the
treatment process used NaMnO4, instead of chlorine, for As(III) oxidation. However, as mentioned
above, oxidant addition was later discontinued because iron removal was accomplished through aeration
and As(III) oxidation was attained via a naturally occurring process.
Competing Anions. The adsorption of arsenic onto iron solids and AD-33 media also may be influenced
by the presence of competing anions such as silica, sulfate, and phosphate. At the Stewart, MN, site,
silica levels ranged from 24.0 to 26.6 mg/L (as SiO2) and sulfate levels ranged from <5 to 7.4 mg/L.
These concentrations were low enough that they did not pose a significant problem for effective arsenic
adsorption. The orthophosphate level was 0.02 mg/L; however, as discussed in Section 4.5.1.6, the total
phosphorous
17
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Table 4-1. City of Stewart, Minnesota, Water Quality Data
Parameter
Sampling Date
pH
DO
ORP
Alkalinity (as CaCO3)
Hardness (as CaCO3)
Turbidity
TDS
TOC
Total N (Nitrate + Nitrite)
Nitrate (as N)
Nitrite (as N)
Ammonia (as N)
Chloride
Fluoride
Sulfate
Silica (as SiO2)
Orthophosphate (as PO4)
As (total)
As (soluble)
As (paniculate)
As(III)
As(V)
Fe (total)
Fe (soluble)
Mn (total)
Mn (soluble)
U (total)
U (soluble)
V (total)
V (soluble)
Na
Ca
Mg
Ra-226
Ra-228
Gross-Alpha
Gross-Beta
Radon
Unit
S.U.
mg/L
mV
mg/L(a)
mg/Lw
NTU
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
mg/L
mg/L
mg/L
pCi/L
pCi/L
pCi/L
pCi/L
pCi/L
Source Water
Utility
Data(a)
Not Specified
7.8
NS
NS
415
230
NS
NS
6.8
NS
NS
NS
NS
6.5
NS
7.4
24.0
0.02
39.0
NS
NS
39
0.1
1,400
NS
24.0
NS
NS
NS
NS
NS
87
46
28
NS
NS
NS
NS
NS
Battelle
Data*11'
08/30/04
7.7
2.2
-86
424
246
7
462
7.2
NS
0.04
0.01
1.7
7.2
0.4
<5.0
26.6
0.1
41.7
32.9
8.8
31.9
1.0
1,344
1,359
27.0
28.0
0.1
0.1
0.1
0.1
87
56
26
<1.0
<1.0
NS
NS
NS
Historic Utility
Distribution
Water Data(c)
10/16/01-10/18/04
7.7-7.8
NS
NS
410-420
<240
-------
level was elevated at 0.90 mg/L (as PO4) and could compete with arsenic for available adsorption sites
onto iron solids and AD-33 media.
Other Water Quality Parameters. Alkalinity, hardness, sodium, and total dissolved solids (TDS) levels
in source water were all elevated. Alkalinity values ranged from 415 to 424 mg/L (as CaCO3); hardness
values ranged from 230 to 246 mg/L (as CaCO3); and sodium and TDS concentrations (in the August 30,
2004, sample) were 87 and 462 mg/L. Other water quality parameters, including nitrate, nitrite, chloride,
fluoride, uranium, and vanadium, were below their respective detection limits or SMCLs. Radium was
measured at less than the detection limit of < 1.0 pCi/L.
4.1.2 Treated-Water Quality and Distribution System. Historic water samples were taken from
both Wells No. 3 and 4, but following chlorination, fluoridation, and polyphosphate addition; therefore,
the analytical results obtained from the Minnesota Department of Health (MDH) are included in Table 4-
1 as distribution water data. These water samples were collected from residences, businesses (stores), city
hall, and the treatment plant from October 16, 2001, through October 18, 2004.
Historic arsenic levels detected within the distribution system ranged from 34.0 to 43.0 (ig/L; iron levels
ranged from 1,200 to 1,500 (ig/L, and manganese levels ranged from 22 to 25 (ig/L. These concentrations
were similar to those measured in source water. Results of other water quality parameters measured
historically also were very close to those found in the source-water samples collected by the facility and
Battelle.
The distribution system at Stewart, MN is supplied only by Wells No. 3 and 4. Water from Wells No. 3
and 4 is blended within the distribution system and the 65,000-gal water tower. Based on the distribution
system blueprint, the mains for the water distribution system are primarily constructed of 6-in to 8-in cast
iron. Other connections within the distribution system include 3/t-in to 2-in galvanized iron, 2-in copper,
and 2-in polyvinyl chloride (PVC) piping. Three locations were selected for both baseline and
distribution system sampling after system startup. The locations were selected as part of the city's
historic sampling network for LCR. Compliance samples also included quarterly sampling for arsenic,
coliform, total chlorine residual, and fluoride and annual sampling for nitrate, volatile organic compounds
(VOCs), trihalomethanes (THMs), haloacetic acids (HAA5), turbidity, TOC, alkalinity, and
radionuclides.
4.2 Treatment Process Description
The 250-gpm treatment system at Stewart, MN, consisted of pre-treatment for iron removal, followed by
adsorption with AD-33 media for arsenic removal (Figure 4-6). This section provides a detailed
description of the Siemens Type IIAERALATER® system for iron removal and AdEdge APU-300
system for arsenic adsorption.
Due to elevated iron levels in source water, the adsorption system was preceded by a Siemens Type II
AERALATER® system for iron (and some arsenic) removal via oxidation and filtration. Figure 4-7
shows the 11-ft-diameter AERALATER® system, which is a packaged unit for oxidation, detention, and
gravity filtration. The AERALATER® system included an aeration chamber, a detention tank, and four
filter cells. The treatment processes were permanganate oxidation (with the oxidant added at inlet piping
to the AERALATER® system), aeration, adsorption/co-precipitation of As(V) onto/with iron solids, and
gravity filtration with anthracite and silica sand. The filtration media are approved for use in drinking-
water applications under NSF International (NSF) Standard 61. More details on the Siemens' Type II
AERALATER® system are provided below.
19
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Explanation
Liquid Process Line
Backwash Line
Pumped
to Sewer
Figure 4-6. Schematic of AERALATER® and APU-300 Systems at Stewart, Minnesota
Figure 4-7. AERALATER® (left) and APU-300 Systems (right) at Stewart, Minnesota
20
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The soluble As(V) that remained in the treated water after the AERALATER® system was further treated
by the AdEdge APU-300 system. Designed for arsenic removal for small systems in the flow range of 10
to 300 gpm, the APU series is a fixed-bed adsorption system. As groundwater is pumped through fixed-
bed pressure vessels, soluble arsenic is adsorbed onto the media, thus reducing the soluble arsenic
concentration to below 10 (ig/L MCL. The APU-300 adsorption system consisted of two 63-in-diameter,
86-in-tall vessels configured in parallel (see Figure 4-7). Each vessel contained 64 ft3 of pelletized
Bayoxide® E33 media (branded as AD-33 by AdEdge). This iron-based adsorptive media was developed
by Bayer AG for the removal of arsenic from drinking-water supplies. Table 4-2 presents the physical
and chemical properties of the media. The AD-33 media is delivered in a dry crystalline form and listed
by NSF under Standard 61 for use in drinking water applications. AD-33 is available in both granular and
pelletized forms. The pelletized media used at the Stewart, MN site is 25% denser than the granular
media (35 vs. 28 lb/ft3). Both media are reported by the vendor to have similar arsenic adsorption
capacities on a per pound basis. After reaching its capacity, the spent media would be removed and
disposed of as nonhazardous waste after passing EPA's toxicity characteristic leaching procedure (TCLP)
test. The media life depends on the arsenic concentration, pH, and concentrations of interfering ions in
the influent water.
Table 4-2. Physical and Chemical Properties of AD-33 Media
Parameter
Value
Physical Properties
Matrix
Physical Form
Color
Bulk Density (Ib/fV)
BET Surface Area (m2/g)(a)
Attrition (%)(a)
Moisture Content (%)
Particle Size Distribution
(U.S. Standard Mesh)
Crystal Size (A)w
Crystal Phase(a)
Iron oxide/Hydroxide
Dry pelletized media
Amber/rust
35
142
0.3
5% by weight
14 x 18
70
a-FeOOH
Chemical Analysis"'
Constituents
FeOOH
CaO
MgO
MnO
S03
Na2O
Ti02
Si02
A1203
P205
Cl
Weight (%)
90.1
0.27
1.00
0.11
0.13
0.12
0.11
0.06
0.05
0.02
0.01
Note: BET = Brunauer, Emmett, and Teller Method.
(a) For dry granular media.
Data Source: Bayer AG.
21
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Table 4-3 presents design features of the treatment system at Stewart, MN. The major process
components of the treatment system are described as follows:
• Intake. Source water was pumped from Wells No. 3 and 4 alternately, and fed into the entry
piping of the Siemens Type II AERALATER® unit. The well pumps were turned on and off
based on the low- and high-level settings of 23 and 27 ft of water, respectively, in the water
tower.
• Oxidation. The original design called for the use of a 2% KMnO4 solution at a target dosage
of 0.5 mg/L (as Mn) to oxidize As(III) and Fe(II). Before system startup, modifications were
made by the city to use a 20% NaMnO4 solution instead. The NaMnO4 solution was fed into
the system with a 1 gal/hr (gph) electronic positive displacement metering pump. In addition
to the metering pump with adjustable stroke length and speed, the chemical feed system
included a 150-gal polyethylene day tank and a 1/3-hp propeller tank mixer. The addition of
NaMnO4 was discontinued at the initial stage of the performance evaluation study (around
February 14, 2006) because oxidation of As(III) was accomplished via naturally mediated
processes without the use of any oxidant.
• Iron Removal. Siemens' Type II AERALATER® was used as a pretreatment step for iron
removal. Constructed of carbon steel, the 11-ft-diameter package unit was designed to allow
oxidation, detention, and gravity filtration to all occur in a single unit. The system
components were assembled in a stacked circular configuration, with an aeration chamber on
the top, a detention tank in the middle, and four filter cells in the base (Figure 4-8). Details of
these process components are described below:
o Aeration. Air for the aluminum aeration unit was supplied by a !/2-hp induced-draft air
blower with a capacity of 855 ft3/min (cfm) at a 3/8-in static pressure. The influent water
was aerated as it passed over a network of 1 %-in PVC slats supported by a stainless-steel
grid.
o Contact. The 11-ft-diameter by 11.5-ft-high steel detention tank provided 34 min of
contact time to improve the formation of filterable iron floes. The total detention time of
34 min was based on the total volume of 8,550 gal in the detention tank, the freeboard
above the filter, and the design flowrate of 250 gpm.
o Filtration. The four filter cells sitting at the base of the circular unit had a total cross-
sectional area of 95 ft2. Therefore, operating the system at the design flowrate of 250
gpm would result in a hydraulic loading rate of 2.6 gpm/ft2. The filtration bed in each
filter cell consisted of one each 12-in layer of 0.6 to 0.8 mm anthracite and 0.45 to 0.55
mm sand, which were supported by a 14-in layer of gravel underbedding. A steel plate
underdrain with media-retaining strainers was located under the gravel.
o Backwash. The filter cells were backwashed manually once per week to remove filtered
particles from the filter media (the system did not have automatic backwash capabilities).
Each cell was backwashed individually at 285 gpm (or 12 gpm/ft2) using filtered water
from the other cells. To initiate the manual backwash, the influent valve on the first cell
was closed and the corresponding backwash valve was opened. The backwash was
continued until visual observation indicated that the backwash wastewater had reached a
"light straw" color. As a result, the duration of the backwash varied based on operator
observations. Upon completion, the backwash valve was closed and the influent valve on
the first cell was re-opened. The same procedure was followed for the remaining filter
22
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Table 4-3. Design Specifications of Type II AERALATER® and APU-300 Systems
Parameter
Value
Remarks
Preoxidation
Oxidant
2%KMnO4
Changed to 20% NaMnO4 by city
before system startup
AERALA TER® System
Design Flowrate (gpm)
AERALATER® Diameter (ft)
AERALATER® Height (ft)
Aerator Cross-Sectional Area (ft2)
Detention Tank Size (ft)
Detention Tank Volume (gal)
Detention Time (min)
Media Volume (ft3)
Hydraulic Loading Rate to Filter (gpm/ft2)
Backwash Flowrate (gpm)
Backwash Hydraulic Loading (gpm/ft2)
Backwash Frequency (time/week)
Backwash Duration (min)
Wastewater Production (gal/filter cell)
250
11
26
95
11D x 11. 5H
8,550
34
190
2.6
285
12
1
0
~o
2,250
-
-
-
-
Including freeboard above filter
-
24-inbed depth (12-in anthracite and
12-in sand)
-
-
-
Variable based on visual observation
Per vendor estimate
APU-300 Adsorbers
Vessel Size (in)
Cross-Sectional Area (ft2/vessel)
Number of Vessels
Configuration
Media Type
Media Volume (ft3)
Pressure Drop (psi)
63 D x 86 H
21.6
2
Parallel
AD-33
128
4 psi
-
Based on 62-in inner diameter
-
-
Pelletized media
36-in bed depth or 64 ft3/vessel
Across a clean bed
APU-3QQ Service
Design Flowrate (gpm)
Hydraulic Loading (gpm/ft2)
EBCT (min)
Estimated Working Capacity (BV)
Throughput to Breakthrough (gal)
Average Use Rate (gal/day)
Estimated Media Life (month)
250
5.8
3.8
82,500
79,000,000
48,600
53
-
-
-
Projected by vendor, 1 BV = 958 gal
-
-
Estimated frequency of change-out at
13. 5% utilization
APU-300 Backwash
Pressure Differential Setpoint (psi)
Backwash Flowrate (gpm)
Backwash Hydraulic Loading Rate (gpm/ft2)
Backwash Frequency (per quarter)
Backwash Duration (min/vessel)
Fast Rinse Duration (min/vessel)
Wastewater Production (gal/vessel)
10
200
9.3
1
15
5
4,000
-
-
Per vendor recommendations
-
-
-
23
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11 '-0" Diameter Type II Aeralater
Waterwash Style Unit
Level Control
Float
6" Influent Connection
8" Cell Influent Valve, Lever Operated
8" Backwash Waste Valve
8" Backwash Waste Pipe
8" Backwash Waste Drop Pipe
Ground Surface
CONCEPTUAL
FRONT/SIDE COMBINATION
ELEVATION VIEW
FS AERALATOR02.CDR
NOT TO SCALE
Drain to Waste
Figure 4-8. Schematic of Type II AERALATER* System (based on general
arrangement drawing provided by Siemens)
cells. All filter cells had to be backwashed on the same day to ensure consistent filter
performance. After all four cells were backwashed, the system effluent valve was re-
opened and the system returned to service. The backwash wastewater produced was
discharged to a sump and then drained by gravity to two backwash wastewater holding
tanks before being pumped to the sewer system.
Adsorption. The AdEdge APU-300 system was fed by two 15-hp vertical end suction high-
service pumps to provide pressurized flow to the water tower rated at 210 gpm at 145 ft total
dynamic head (TDH). The high-service pumps were controlled to start and stop operations
based on the water level in the AERALATER® detention tank. The APU-300 adsorption
system consisted of two 63-in-diameter, 86-in-tall vessels configured in parallel, each
containing 64 ft3 of pelletized AD-33 media supported by gravel underbedding. Figure 4-9
shows the schematic of the APU-300 system. The adsorption vessels were constructed of
composite fiberglass with a polyethylene liner and rated for 150 pounds per square inch (psi)
working pressure. The system was skid-mounted and piped to a valve rack mounted on a
polyurethane-coated, welded frame. The service, backwash, and media replacement are
described in more detail below.
o Service. Water flowed downward through the packed AD-33 media beds. Flow to each
vessel was measured and totalized to record the volume of water treated. The pressure
differential through each vessel also was monitored. Based on a design flowrate of 250
gpm, the empty bed contact time (EBCT) for each vessel was 3.8 min, and the hydraulic
loading to each vessel was approximately 5.8 gpm/ft2.
24
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System
Feed
Inlet
\m
Explanation
(FM) Flow Monitor/Sensor
(p) Pressure Gauge
P®( Butterfly Valve with Electric Actuator
(DP) Differential Pressure Gauge
System
Outlet
System
~~*" Backwash
PROCFLOW01.CDR
Figure 4-9. Schematic of APU-300 System (Based on Process and
Instrumentation Diagram Provided by AdEdge)
o Backwash. Based on a set time period or a set pressure differential, the adsorption
vessels were taken off-line one at a time for a manual backwash, using source water from
the wells. The system was equipped with an automatic backwash trigger based on time
or differential pressure, but this feature was disabled. The purpose of the backwash was
to remove particulates and media fines built up in the beds and to uncompress the media
beds. While one vessel was backwashed, the other vessel remained in service. Each
vessel was backwashed at a flowrate of approximately 200 gpm (or 9.3 gpm/ft2). The
backwash wastewater generated was discharged to a sump and then drained by gravity to
two 13,000-gal backwash wastewater holding tanks before being pumped to the sewer
system. Each holding tank was equipped with a 3-hp submersible centrifugal sludge
pump rated for 50 gpm at 20 ft TDH.
o Media Replacement. During the performance evaluation study, the adsorption media
was not exhausted, so the media was not replaced. When the AD-33 media arsenic
removal capacity is exhausted, the spent media will be removed from the vessels and
disposed offsite. Virgin media is then loaded back into each vessel. Based on the
vendor's estimate, the media will be changed out after treating approximately 79 million
gal or 82,500 BV, given influent arsenic concentrations from 20 to 27 |o,g/L.
• Post-Treatment Chemical Feed. After the APU-300 system, the treated water underwent
post-chlorination, fluoridation, and polyphosphate addition. Post-chlorination was carried out
with a gas chlorine injection system, which consisted of two 150-lb chlorine gas cylinders, a
digital, dual-cylinder scale rated for a capacity of 349 Ib, a flow controller, and a 3-hp
chlorine booster pump. Post-chlorination helped maintain a target total chlorine residual
level of 1.1 mg/L (as C12) in the distribution system. Fluoride was added at a target level of
1.3 mg/L, using a 0.58-gph maximum capacity, electronic, positive-displacement metering
pump and a 65-gal polyethylene storage tank. Blended polyphosphates were added with a
25
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0.58-gph maximum capacity, electronic, positive-displacement metering and a 50-gal
polyethylene storage tank for corrosion control.
4.3 Treatment System Installation
4.3.1 Permitting. The system engineering package, prepared by AdEdge and Bolton & Menk,
Inc., included (1) a system design report and associated general arrangement as well as piping and
instrumentation diagrams (P&IDs) for the Type II AERALATER® and APU-300 systems; (2) electrical
and mechanical drawings and component specifications, and (3) building construction drawings detailing
connections from the system to the entry piping and the city's water and sanitary sewer systems. The
engineering package was certified by a Professional Engineer registered in the State of Minnesota and
submitted to MDH for review and approval on March 21, 2005. After MDH's review comments were
incorporated, the revised package was resubmitted on May 20, 2005. MDH issued a water supply
construction permit on June 20, 2005, and system fabrication began thereafter.
4.3.2 Building Construction. The city applied for building construction permit, which was issued
on June 13, 2005. Building construction began on July 1, 2005, and was completed on February 9, 2006.
The concrete block building had a 55.3-ft * 24.7-ft footprint with a sidewall height of 14 ft (see Figure 4-
10). The AERALATER® aeration tower protrudes through the building roof where two 16-in-diameter
access hatches also were installed for adsorptive media loading. In addition to housing the treatment
system, the building contains a fluoride room, a chemical room, a bathroom, and some office/laboratory
space. Wastewater discharge is facilitated with a 4-ft x 2-ft x 2-ft (120 gal) underground sump that
empties by gravity into two 12,500-gal, pre-cast concrete holding tanks. Each holding tank is equipped
with a 2-hp sump pump with a design capacity of 50 gpm for transferring backwash wastewater to the
sanitary sewer system.
4.3.3 System Installation, Shakedown, and Startup. Although building construction was
ongoing, the site was prepared for delivery of the treatment systems by September 2005. Both units were
shipped and arrived prior to roof construction to facilitate placement of the units in the building. The
APU-300 system arrived on September 6, 2005, and the AERALATER® system arrived on September 16,
2005. The vendor, through its subcontractor, off-loaded and installed the systems, including connections
to the entry and distribution piping and electrical interlocks. Figure 4-11 shows the off-loading of the
AERALATER® unit by crane.
Subsequent to the treatment system delivery, construction work to finish the building and associated
piping and electrical infrastructure continued through February 9, 2006. Siemens arrived onsite for
mechanical checkout of the AERALATER® installation on January 4, 2006. AdEdge was onsite from
January 4 to 11, 2006, for mechanical checkout of the APU-300 installation and startup activities,
including hydraulic testing, media loading, initial backwashing, and system disinfection. After the
bacteriological test results were received and passed, the systems began to operate manually, with the
treated water sent to the distribution system starting on January 18, 2006. Manual operation of the
systems continued until the city's contractor completed the electrical wiring and control setpoints for the
well pumps and high-service pumps. The operator began to record operational data on January 30, 2006.
Battelle staff traveled to Stewart, MN to perform system inspections and operator training from February
1 to 3, 2006, with the first set of treatment plant samples taken on February 2, 2006. A punch list was
identified during the trip and later forwarded to AdEdge on February 16, 2006. The issues to be
addressed included replacement of a headless gauge on the AERALATER® system; installation of a
combined effluent sample tap downstream of the APU-300 system and upstream of post-chlorination;
disabling of the APU-300 system automatic backwash; calibration of flow meters for the APU-300
26
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Figure 4-10. Building with AERALATER® Tower (top), Backwash Sump (bottom left),
and Backwash Wastewater Holding Tanks (bottom right) at Stewart, Minnesota
Figure 4-11. Off-Loading and Placement of AERALATER® Unit at Stewart, Minnesota
27
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System; and changes of combined flow totalizer programmable logic controller (PLC) programming for
the APU-300 system. The vendor subsequently resolved these issues by August 2006.
4.4
System Operation
System operation data were tabulated and are attached as Appendix A. Key parameters are summarized
in Table 4-4. From February 2, 2006, to February 28, 2007, the system operated for 1,821 hr, producing
20,441,000 gal based on wellhead flow totalizer readings. The wells were operated on an alternating
basis, with Well No.3 operating for 908 hr and Well No. 4 for 913 hr. The average daily demand was
52,418 gal, and the average operation time was 4.7 hr/day. Given the full design capacity of 250 gpm
(360,000 gpd), this represents an average hydraulic utilization rate of 15% on a daily basis. The system
operation is discussed below in terms of the hydraulic performance of the AERALATER® and APU-300
systems.
Table 4-4. Summary of Treatment System Operation at Stewart, Minnesota
Operational Parameter
Operational Period
Wellhead Operations
Total Operating Time (hr)
Average Operating Time (hr/day)
Throughput (kgal)
Average Demand (gpd)
AERALATER" Iron Removal Operations
Average Flowrate [Range] (gpm)(a)
Average Detention Time [Range] (min)
Average Filtration Rate [Range] (gpm/ft2)
Average Ap across Filter (ft H2O)
Average Throughput Between Backwash [Range]
(kgal)
Average Run Time Between Backwash [Range] (hr)
Average Backwash Frequency [Range]
(day /backwash)
APU-300 Adsorption Operations
Throughput (kgal)
Throughput (BV)
Average Flowrate [Range] (gpm)(b)
Average EBCT [Range] (min)
Ap across tank/system (psi)
Values
February 2, 2006 to February 28, 2007
Well No.3
908
2.33
10,421
26,700
Well No.3
191 [100-217]
45 [39-86]
2.0 [1.1-2.3]
-
—
-
—
Tank A
10,181
21,264
88 [66-104]
5.4 [4.6-7.2]
0
Well No.4
913
2.34
10,020
25,718
Well No.4
184 [127-248]
46 [34-67]
1.9 [1.3-2.6]
-
—
-
—
TankB
10,289
21,489
88 [62-103]
5.4 [4.6-7.7]
0
Total
1821
4.7
20,441
52,418
Total
-
-
-
<1.5
368 [138-739]
33 [13-68]
7 [3-15]
Total
20,470
21,377
176 [128-207]
5.4 [4.6-7.5]
Ito2
(a) Average flowrate based on readings of individual wellhead mechanical flow totalizers and hour meter.
(b) Average flowrate based on weekly readings of instantaneous flowrate from each vessel using digital
paddlewheel flow meters.
4.4.1 AERALATER® Operations. With an average flowrate of 188 gpm between the two wells,
the AERALATER® system was run at approximately 75% of its full design capacity of 250 gpm. The
flowrate to the AERALATER® system varied slightly, based on which well pump was operational. When
Well No. 3 was operational, flowrate readings ranged from 100 to 217 gpm and averaged 191 gpm. At
these flowrates, the detention times ranged from 39 to 86 min and averaged 45 min (compared to a design
value of 34 min); the hydraulic loading rates to the filter ranged from 1.1 to 2.3 gpm/ft2 and averaged 2.0
gpm/ft2 (compared to the design value of 2.6 gpm/ft2). When Well No. 4 was operational, the flowrate
readings ranged from 127 to 248 gpm and averaged 184 gpm. This corresponded to a detention time of
28
-------
34 to 67 min (averaged 46 min) and a hydraulic loading rate of 1.3 to 2.6 gpm/ft2 (averaged 1.9 gpm/ft2).
In general, the detention time was longer and the hydraulic loading rate was lower than the respective
design values.
During the 1-year performance study, 54 backwash events took place. The operator manually
backwashed the AERALATER® system approximately once per week, with the number of days per
backwash ranging from 3 to 15. During the filter run cycles, less than 1.5 ft of water head loss was
measured across the filter media beds. The run times between two consecutive backwash events ranged
from 13 to 68 hr, and the average run time was 33 hr. The throughput between two consecutive backwash
events ranged from 138,100 to 739,000 gal, and the average throughput was 368,000 gal. The throughput
to the filter varied, based on the amount of run time required to meet the water demand during the week.
4.4.2 APU-300 Operations. The APU-300 system processed approximately 20,470 kgal, or
21,377 BV of water, from February 2, 2006, through February 28, 2007, based on readings from the
individual digital paddle-wheel flow totalizers installed on the effluent piping downstream from the
adsorption vessels. In general, the throughput readings obtained via the paddle-wheel flow totalizers were
consistent with those from the totalizers at the wellheads, with relative error within 2.1%, given the
wellhead throughput and estimated backwash wastewater volume. Based on the readings for the
individual vessels, Vessel A processed 21,264 BV (10,181,000 gal) of water and Vessel B processed
21,489 BV (10,289,000 gal).
Each week, the operator recorded the instantaneous flowrates through Vessels A and B based on the
digital paddlewheel flow meter for each vessel. As shown in Figure 4-12, the flowrates through Vessels
A and B were generally at the same level. The average flowrate was 88 gpm for both Vessels A and B,
indicating balanced flow between them. According to the flowrates measured, the system operated at
approximately 70% of its design capacity. The EBCTs for both Vessels A and B averaged 5.4 min, which
is higher than the design value of 3.8 min. Throughout the performance evaluation study, the differential
pressure across the adsorption system remained low at 1.0 to 2.0 psi, indicating effective particulate
removal by the AERALATER® system. The four manual backwash events conducted during the
performance evaluation study are discussed in detail below.
4.4.3 Backwash Operations. Both the AERALATER® and APU-300 systems required backwash.
Because the AERALATER® system was used as pre-treatment to remove iron particles, it was
backwashed as often as once per week. The APU-300 system did not experience elevated differential
pressures above the 10-psi setpoint; it was, therefore, backwashed only four times during the 1-year
performance evaluation study. Both units used treated water for backwash. Table 4-5 summarizes key
operational parameters related to system backwash for both systems.
The 54 manual backwash events of the AERALATER® system generated approximately 406,400 gal of
backwash wastewater, based on the readings obtained via the wellhead totalizer readings before and after
backwash. The amount of wastewater produced represents 2% of the volume of water processed during
this time period. The average backwash flowrate was 215 gpm, or 9.1 gpm/ft2, which was about 25%
lower than the design value of 285 gpm or 12 gpm/ft2. The duration for each backwash event (for all four
cells) ranged from 15 to 60 min and averaged 36 min, which is slightly higher than the vendor-provided
value of 8 min/cell or 32 min/event. The backwash duration varied because backwash was manually
controlled by the operator based on visual observations of the color of backwash wastewater. The
backwash was discontinued when the backwash wastewater had reached a "light straw" color. The
average amount of wastewater produced was 7,619 gal per backwash event, compared to 9,000 gal per
event specified by the vendor.
29
-------
Q.
U>
120
100
Figure 4-12. Instantaneous Flowrates Through Adsorption Vessels A and B
Table 4-5. Summary of Backwash Operations at Stewart, Minnesota
Parameter
Value
AERALATER® Backwash Operations
Total Number of Backwash Events
Total Volume of Backwash Wastewater Produced (gal)
Average Frequency of Backwash [Range] (day)
Average Flowrate [Range] (gpm)
Average Hydraulic Loading Rate [Range] (gpm/ft2)
Average Duration [Range] (min)
Average Backwash Wastewater Volume [Range] (gal/event)
54
406,400
7 [3-15]
215 [157-387]
9.1 [6.6-16.3]
36 [15-60]
7,619 [3,600-12,400]
APU-300 Backwash Operations
Total Number of Backwash Events
Total Volume of Backwash Wastewater (gal)(a)
Average Backwash Wastewater Volume [Range] (gal/vessel)(b)
4
25,415
2,963 [2,578-3,392]
(a) Backwash wastewater volumes, including fast rinse water.
(b) Calculations do not include Vessel A backwash that was initiated and then
halted on February 2, 2006.
The recommended AD-33 media backwash frequency was once every 45 days. The system was equipped
with an automatic backwash control that initiated backwash either by a 45-day time trigger or by a
differential pressure trigger set at 10 psi across each vessel. Because of the process control configuration
of the well pumps and high-service pumps, the automatic backwash feature was disabled. Per
communication with the operator during the startup trip in February 2006, it was determined that there
was no wiring connection between the APU-3 PLC and the city's PLC that controlled the well pumps and
30
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high-service pumps. Therefore, if an automatic backwash was called for while the well pumps and high-
service pumps were off, adequate flow would not be available to the APU-300 units to accomplish the
backwash. For this reason, the automatic backwash capability was disabled in the PLC on February 2,
2006, and the operator performed each backwash of the APU-300 unit with a manual trigger. The four
manual backwashes occurred on February 2, February 22, and October 12, 2006, and on January 16, 2007
as described below.
The backwash on February 2, 2006, occurred during startup activities to confirm proper installation and
setup of the system. During this event, it was noted that further adjustments were required to the PLC
settings and to the backwash flowrate to meet design specifications. During the backwash of Vessel A, a
higher than specified backwash flowrate of greater than 275 gpm (or 13 gpm/ft2) was noted, along with
visual observation of media loss discharged through the backwash line. Shortly after initiation of
backwash, the operator throttled back the flowrate to approximately 181 gpm (or 8.6 gpm/ft2), a value
below the design flowrate of 200 gpm (or 9.5 gpm/ft2). It also was noted that the backwash and fast rinse
time setpoints required adjustment in the PLC. Therefore, the backwash of Vessel A was halted after 28
min to make these adjustments. The backwash time was changed from 1,200 sec (20 min) to 900 sec (15
min) to match the design value of 15 min. The fast rinse time also was adjusted from 1,500 sec (25 min)
to 180 sec (3 min) to be closer to the 5-min design value. During this backwash, Vessels A and B
generated 4,668 and 2,979 gal of wastewater, respectively. The operator subsequently performed manual
backwash events on February 22, 2006, October 12, 2006, and January 16, 2007 that generated 3,026,
2,857, and 2,578 gal of wastewater from Vessel A, respectively, and 2,799, 3,392, and 3,116 gal of
wastewater from Vessel B, respectively. Except for Vessel A on February 2, 2006, backwash produced
smaller amounts of wastewater than the design value of 4,000 gal/vessel. During the 1-year system
operation, backwash of the adsorption vessels produced 25,415 gal of wastewater, which represents
0.12% of the total amount of water processed.
4.4.4 Residual Management. The residuals produced by the treatment system at Stewart, MN
included backwash wastewater produced from the gravity filter and adsorption vessels. The wastewater
produced was discharged to the building sump, which emptied by gravity to two holding tanks before
being pumped to the sanitary sewer. The total volume of wastewater produced was 431,815 gal, which
represents a wastewater generation rate of approximately 2.1%. The AD-33 media was not exhausted
during the 1-year performance evaluation study, so there were no residuals associated with spent media.
4.4.5 Reliability and Simplicity of Operation. No significant scheduled or unscheduled
downtime was required during the 1-year performance evaluation study. The simplicity of system
operation and operator skill requirements is discussed, including pre- and post treatment requirements,
levels of system automation, operator skill requirements, preventive maintenance activities, and frequency
of chemical/media handling and inventory requirements.
4.4.5.1 Pre- and Post-Treatment Requirements. Due to the high TOC and ammonia levels in source
water, KMnO4, instead of chlorine, was originally selected to oxidize As(III) and Fe(II). However, prior
to system startup, the operator indicated his preference of using liquid NaMnO4 instead of powdered
KMnO4. Subsequently, a modification of the initial design was implemented by the city in December
2005 to include the use of a 20% liquid NaMnO4 solution with a 1-gph chemical-metering pump. To
achieve the target dosage, the chemical-metering pump operated with a 25% stroke and 2.5% speed
settings. Based on measurements with a calibration cylinder, these settings corresponded to a 0.092-gph
application rate, equivalent to only 9.2% of the pump's maximum capacity. The pump size and low
settings contributed to difficulties in controlling the NaMnO4 dose, and the pump appeared to have lost
prime after February 2, 2006. Without NaMnO4 injection, it was observed that iron continued to be
removed, presumably by aeration and that As(III) continued to be oxidized to As(V) via unidentified
31
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processes within the AERALATER® gravity filter (see Section 4.5.1.1). No post-treatment requirements
existed related to the arsenic-removal system.
4.4.5.2 System Automation. The wellhead and high-service pumps were automatically controlled by
a PLC installed by the city. The AERALATER® system did not require significant automation other than
the level sensors in the detention tank that controlled operation of the high-service pumps. The
AERALATER® system did not include automatic backwash triggers, which could be added as a system
upgrade. Because the system needed to be backwashed only weekly, the lack of automation for the
gravity filter backwash was not a significant inconvenience. However, this lack of automation would
likely be an issue at a site requiring more frequent backwash. As noted in Section 4.4.3, it was necessary
to disable the automatic backwash capability of the APU-300 system. It was determined that there was no
wiring connection between the APU-300 PLC and the city's PLC that controlled the well pumps and
high-service pumps. Therefore, if an automatic backwash was called for while the well pumps and high-
service pumps were off, there would not be adequate flow to the adsorption vessels to accomplish the
backwash. The city decided not to pursue a change to the control system and to manually backwash the
adsorption vessels when required.
4.4.5.3 Operator Skill Requirements. Under normal operating conditions, the daily demand on the
operator was approximately 10 min for visual inspection of the system and recording on filed log sheets
of operational data such as pressure, volume, and flowrate. The manual backwash operations required an
average of 31 min of the operator's time once per week. This is equivalent to approximately 1.7 hr of
labor per week. The operator also performed routine weekly and monthly maintenance according to the
users' manual to ensure proper system operation. Normal operation of the system did not appear to
require additional skills beyond those necessary to operate the existing water supply equipment.
The state of Minnesota has five water operator certificate class levels (A, B, C, D, and E with A being the
highest). The certificate levels are based on education, experience, and system characteristics, such as
water source, treatment processes, water storage volume, number of wells, and population affected. The
water operator for the City of Stewart has a Class C certificate. Class C requires a high school diploma or
equivalent with at least 3 years of experience in operating Class A, B, or C system or a bachelor's degree
from an accredited institution with at least 1 year of experience in operating a Class A, B, C, or D system.
4.4.5.4 Preventive Maintenance Activities. Recommended maintenance activities for the
AERALATER® system include annual inspection of the aerator internals and slats to monitor iron build-
up and perform cleaning if necessary; a complete interior inspection every 2 years by Siemens; and
mechanical and electrical aerator blower checks if performance issues arise. Preventive maintenance
tasks for the APU-300 system recommended by the vendor include monthly inspection of the control
panel; quarterly checking and calibration of flow meters; biannual inspection of actuator housings, fuses,
relays, and pressure gauges; and annual inspection of the butterfly valves. The vendor recommended
checking the actuators at each backwash event to ensure that the valves were opening and closing in the
proper sequence. Further, inspection of the adsorber laterals and replacement of the underbedding gravel
were recommended to be concurrent with the media replacement. During the 1-year performance
evaluation study, two relays that controlled the electrically actuated values on the APU-300 system were
replaced, using spare relays in the PLC panel. No other significant repair and maintenance activities were
reported during the period.
4.4.5.5 Chemical-Handling and Inventory Requirements. No chemical-handling requirements were
necessary because iron removal occurred by aeration, and because oxidation of As(III) to As(V) was
occurring within the AERALATER® filter (see Section 4.5.1.1). Chemical handling of NaMnO4 was
required only initially from January 18 to February 2, 2006, during the system shakedown stage.
32
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4.5 System Performance
The performance of the AERALATER® and APU-300 systems was evaluated based on analyses of water
samples collected from the treatment plant, system backwash, and distribution system.
4.5.1 Treatment Plant. The treatment plant water was sampled at six locations (IN, AC, AF, TA,
TB, and TT) on 49 occasions (including three duplicate events) with field speciation performed during 13
of the 49 occasions. Field-speciation samples were collected at the IN, AC, AF, and TT sampling
locations monthly. Table 4-6 summaries analytical results for arsenic, iron, and manganese. Table 4-7
summarizes results of the other water quality parameters. These tables include data from all 49 sampling
occasions, except for those collected at AC, AF, TA, TB, and TT on February 2, 2006, when NaMnO4
was added. The February 2, 2006, results are included in Appendix B, which contains a complete set of
analytical data. Results of the water samples collected throughout the treatment plant are discussed
below.
4.5.1.1 Arsenic. Figure 4-13 contains four bar charts showing the concentrations of total As,
particulate As, soluble As(III), and soluble As(V) at the IN, AC, AF, and TT sampling locations for each
speciation sampling event. Total arsenic concentrations in source water ranged from 31.4 to 56.4 |o,g/L
with 27.6 to 44.0 |o,g/L existing as soluble As(III). Therefore, As(III) was the predominant species.
Lower levels of soluble As(V) and particulate arsenic also were present, averaging 5.1 and 6.4 |o,g/L,
respectively. Total arsenic concentrations measured during the performance evaluation study varied in a
wider range than those measured historically (39.0 to 41.7 |og/L), as shown in Table 4-1.
Arsenic Removal with NaMnO4 Addition. Upon completion of shakedown, the treatment system was
operated with NaMnO4 addition for soluble As(III) and Fe(II) oxidation. However, the addition was
disrupted due to loss of prime within 1 week after the first sampling and speciation event on February 2,
2006, based on the measurements of solution level and consumption rate in the chemical day tank.
For the sampling event on February 2, 2006, out of 52.3 |o,g/L of total arsenic in source water, 39.8 |o,g/L
were present as soluble As(III). At 1,240 |o,g/L, iron existed almost entirely as soluble iron. The soluble
As(III) and Fe(II) concentrations were decreased to 4.2 and < 25 |og/L, respectively, following NaMnO4
preoxidation, aeration, and detention. About 0.51 mg/L of NaMnO4 (as Mn) was believed to have been
added to source water based on the difference in total manganese concentrations between the IN and AC
sampling locations. This amount was close to the stoichiometrically estimated dosage of 0.42 mg/L (as
Mn) based on the February 2, 2006, source-water data. Therefore, the amount of NaMnO4 added should
be sufficient to oxidize most, if not all, As(III) and Fe(II) in source water. It should be noted, however,
that the NaMnO4 target dosage was estimated based mainly on the levels of soluble As, Fe, and Mn in
source water (see data in Appendix B) and that the elevated TOC level at 6.7 mg/L could add to the
oxidant demand (see Section 4.5.1.3). The As(V) thus formed, along with the pre-existing As(V), was
adsorbed onto and/or co-precipitated with the iron solids formed during the preoxidation step, resulting in
31.1 ng/L of particulate arsenic after the detention tank.
The February 2, 2006, results also showed the presence of 17.0 (ig/L of soluble As(V) after the detention
tank, indicating incomplete As(V) removal by the naturally occurring iron in source water. The
concentration ratio of soluble iron to soluble arsenic in source water was 26:1 on February 2, 2006, which
was over the 20:1 target ratio for more effective As(V) removal via the iron-removal process (Sorg,
2002). The relatively inefficient As(V) removal observed might have been caused by the relatively high
pH value (8.2) and the presence in source water of competing anions (1.0 mg/L of total phosphorous [as
PO4] and 27.6 mg/L of Si [as SiO2]) and TOC (6.7 mg/L). All could adversely impact the soluble As(V)
removal by natural iron solids.
33
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Table 4-6. Summary of Arsenic, Iron, and Manganese Analytical Results
Parameter
As (total)
As (soluble)
As (participate)
As (III) (soluble)
As (V) (soluble)
Fe (total)
Fe (soluble)
Mn (total)
Mn (soluble)
Sampling
Location(ac)
IN
AC
AF
TA
TB
TT
IN
AC
AF
TA
TB
TT
IN
AC
AF
TA
TB
TT
IN
AC
AF
TA
TB
TT
IN
AC
AF
TA
TB
TT
IN
AC
AF
TA
TB
TT
IN
AC
AF
TA
TB
TT
IN
AC
AF
TA
TB
TT
IN
AC
AF
TA
TB
TT
Number of
Samples
49
48
48
38
36
10
13
12
12
2
0
10
13
12
12
2
0
10
13
12
12
2
0
10
13
12
12
2
0
10
49
48
48
38
36
10
13
12
12
2
0
10
49
48
48
38
36
10
13
12
12
2
0
10
Concentration (|J.g/L)
Minimum
31.4
29.9
19.8
0.4
0.3
<0.1
34.1
32.5
21.9
0.4
NA
<0.1
0.5
<0.1
0.1
<0.1
NA
0.1
27.6
21.7
O.I
0.6
NA
O.I
1.4
6.1
21.8
0.1
NA
0.1
993
919
<25
<25
<25
<25
412
<25
<25
<25
NA
<25
19.6
20.3
21.9
10.7
7.2
22.9
20.3
20.3
22.0
17.5
NA
23.5
Maximum
56.4
56.9
42.7
7.4
9.2
9.8
48.9
44.9
37.4
0.5
NA
8.6
14.0
14.8
12.3
0.3
NA
1.2
44.0
30.8
6.6
1.7
NA
1.1
11.7
23.2
30.8
0.1
NA
7.5
1,491
1,309
29.2
337
524
<25
1,335
68.5
<25
<25
NA
<25
44.3
31.4
47.8
31.2
33.2
34.2
29.7
25.6
41.3
26.0
NA
35.1
Average
44.8
43.8
29.0
_(t>)
_(t>)
_(b)
40.4
36.6
28.0
_(t>)
NA
_(t>)
6.4
10.2
4.2
0.2
NA
0.3
35.3
26.2
1.6
_(t>)
NA
_(t>)
5.1
10.4
26.4
_(b)
NA
_(t>)
1,188
1,142
<25
<25
26.7
<25
922
<25
<25
<25
NA
<25
23.6
23.7
27.5
24.8
25.8
26.5
24.0
23.4
26.5
21.8
NA
26.8
Standard
Deviation
7.1
6.3
5.2
_(t>)
_(t>)
Jf>)
4.7
3.8
3.9
_(t>)
NA
_(t>)
3.9
4.1
4.2
0.2
NA
0.4
5.6
2.6
1.8
_(t>)
NA
(b)
2.9
4.2
2.9
(b)
NA
_(t>)
110
88.8
3.2
52.6
85.3
NA
283
16.9
NA
NA
NA
NA
3.5
1.9
5.7
4.2
5.2
3.4
2.4
1.7
5.2
6.1
NA
3.3
(a) See Table 3-3.
(b) Average and standard deviation not meaningful
(c) Not including results for AC, AF, TA, TB, and
addition.
NA = not applicable.
for arsenic breakthrough data.
TT from the February 2, 2006, sampling event with NaMnO4
34
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Table 4-7. Summary of Other Water Quality Parameter Measurements
Parameter
Alkalinity
(as CaCO3)
Ammonia (as N)
Fluoride
Sulfate
Nitrate (as N)
Total P (as P)
Silica (as SiO2)
Turbidity
TOC
PH
Sampling
Location(ab)
IN
AC
AF
TA
TB
TT
IN
AC
AF
TA
TB
TT
IN
AC
AF
TA
TT
IN
AC
AF
TA
TT
IN
AC
AF
TA
TB
TT
IN
AC
AF
TA
TB
TT
IN
AC
AF
TA
TB
TT
IN
AC
AF
TA
TB
TT
IN
AC
AF
TA
TT
IN
AC
AF
TA
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
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
|ig/L
|ig/L
|ig/L
Mg/L
|ig/L
Mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
NTU
NTU
NTU
NTU
NTU
NTU
mg/L
mg/L
mg/L
mg/L
mg/L
S.U.
S.U.
S.U.
S.U.
Sample
Count
49
48
48
38
36
10
29
28
28
19
17
9
13
12
12
2
10
13
12
12
2
10
30
29
29
19
17
10
49
48
48
38
36
10
49
48
47
38
36
10
49
48
48
38
36
10
11
11
11
1
9
46
45
45
35
Concentration
Minimum
408
410
403
400
367
416
1.0
1.1
0.9
0.6
0.4
1.0
0.3
0.3
0.2
0.4
0.2
<1
<1
<1
<1
<1
<0.05
0.05
O.05
<0.05
0.2
0.3
80.9
247
89.3
<10
<10
<10
23.1
23.1
23.0
23.3
23.5
23.7
4.1
7.1
0.3
0.2
0.2
0.4
6.2
6.2
3.8
6.1
3.1
7.4
7.8
7.7
7.8
Maximum
485
487
476
474
470
469
1.9
1.9
1.7
1.4
1.3
2.3
1.0
0.6
0.6
0.4
0.8
<1
<1
<1
<1
<1
<0.05
0.1
1.5
1.7
1.6
1.4
350
344
158
246
336
111
28.3
28.2
28.1
28.3
28.6
27.0
15.0
15.0
8.3
2.2
3.5
1.3
6.7
7.0
7.0
6.1
6.7
8.2
8.6
8.9
8.4
Average
435
436
436
431
430
438
1.6
1.6
1.4
1.1
1.1
1.2
0.5
0.5
0.5
0.4
0.5
<1
<1
<1
<1
<1
<0.05
0.05
0.3
0.5
0.5
0.5
301
295
112
26.4
33.0
37.2
25.1
25.0
24.9
25.1
25.0
25.2
6.5
9.2
0.9
0.8
0.9
0.8
6.4
6.5
6.2
6.1
6.1
7.9
8.3
8.1
8.2
Standard
Deviation
18.8
19.3
17.1
18.1
21.0
20.0
0.2
0.2
0.2
0.2
0.2
0.4
0.2
0.1
0.1
0.0
0.2
NA
NA
NA
NA
NA
0.0
0.0
0.3
0.4
0.3
0.4
40.9
24.1
13.2
40.1
55.0
32.8
1.1
0.9
1.1
1.0
1.1
1.0
2.0
1.5
1.1
0.4
0.7
0.3
0.2
0.3
0.9
NA
1.2
0.2
0.2
0.2
0.1
35
-------
Table 4-7. Summary of Other Water Quality Parameter Measurements (Continued)
Parameter
pH (Con't)
Temperature
DO
ORP
Total Hardness
(as CaCO3)
Ca Hardness
(as CaCO3)
Mg Hardness
(as CaCO3)
Sampling
Location(ab)
TB
TT
IN
AC
AF
TA
TB
TT
IN
AC
AF
TA
TB
TT
IN
AC
AF
TA
TB
TT
IN
AC
AF
TA
TT
IN
AC
AF
TA
TT
IN
AC
AF
TA
TT
Unit
S.U.
s.u.
°c
°c
°c
°c
°c
°c
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mV
mV
mV
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
mg/L
Sample
Count
33
10
46
45
45
35
33
10
45
43
43
33
31
10
46
45
45
35
33
10
13
12
12
2
10
13
12
12
2
10
13
12
12
2
10
Concentration
Minimum
7.9
7.7
10.1
10.1
10.5
10.6
10.5
10.8
0.5
3.8
1.6
1.5
1.7
2.2
-36.6
39.7
36.6
24.9
23.5
80.0
200
189
206
209
205
88.2
94.8
97.2
103
95.2
94.0
93.9
92.7
105
94.9
Maximum
8.4
8.3
16.6
13.8
19.3
14.3
15.4
13.5
2.2
7.2
4.9
6.2
5.7
6.8
404
360
386
323
321
297
238
236
242
210
247
127
130
134
104
137
118
118
117
106
119
Average
8.2
8.1
11.7
11.4
12.0
12.0
12.3
11.9
1.2
5.0
2.6
2.7
2.7
3.0
216
207
186
158
150
173
218
216
219
210
222
112
111
113
104
115
107
105
107
106
107
Standard
Deviation
0.1
0.2
1.2
0.9
1.5
1.1
1.2
0.7
0.5
0.7
0.8
0.9
0.8
1.4
129
82.0
78.0
72.0
68.8
68.9
13.0
14.4
10.3
0.6
13.3
10.6
11.7
10.0
0.1
11.5
8.6
8.1
6.6
0.7
6.9
(a) See Table 3-3.
(b) Not including results for AC, AF, TA, TB, and TT from the February 2, 2006, sampling event with NaMnO4 addition.
NA = not applicable.
36
-------
Arsenic Speciation at the Wellhead (IN)
60
3 50 -
1
^4
-------
The results on February 2, 2006, also indicated that the gravity filter was highly effective in removing
particulate matter, leaving only 2.7 |o,g/L of particulate arsenic and less than the detection limit of iron in
the filter effluent. Also present in the filter effluent were 17.2 |o,g/L of soluble As(V) and 1.3 |o,g/L of
soluble As(III). As expected, soluble As(V) in the filter influent was left essentially untreated. However,
soluble As(III) concentrations were reduced from 4.2 to 1.3 |o,g/L across the filter bed. Conversion of
soluble As(III) to soluble As(V) in the gravity filter also was observed during the subsequent sampling
events after the addition of NaMnO4 had been inadvertently discontinued due to a pump issue. This
unexpected finding is discussed in the following paragraphs. With NaMnO4 addition, the gravity filter
achieved removal of approximately 60% total arsenic and nearly 100% total iron.
Arsenic Removal Without NaMnO4 Addition. As noted above, after the sampling event on February 2,
2006, the NaMnO4 metering pump lost prime, thus inadvertently discontinuing NaMnO4 addition for
soluble As(III) oxidation. The disruption of chemical addition was confirmed by both the lack of
chemical consumption in the NaMnO4 day tank and the decrease in Mn concentrations in the AC samples
taken after the detention tank starting from the second sampling event on February 14, 2006.
As typified by the results of the first speciation event on February 27, 2006, since discontinuation of
NaMnO4 addition, very little soluble As(III) conversion occurred via aeration, with 34.2 |o,g/L in source
water and 26.4 |o,g/L following aeration and detention. This observation was consistent with the general
notion that aeration was not effective in oxidizing soluble As(III) (Ghurye and Clifford, 2001).
Nonetheless, some soluble As(III) oxidation still occurred, with soluble As(V) concentrations increasing
from 1.4 to 6.1 |o,g/L and particulate arsenic concentrations from 3.2 to 8.9 |o,g/L after aeration and
detention. The amount of particulate arsenic formed via aeration was 5.7 |og/L (i.e., the difference of 3.2
and 8.9 |o,g/L on February 27, 2006), compared to 22.6 |o,g/L (i.e., the difference of 8.5 and 31.1 |o,g/L)
formed following NaMnO4 preoxidation and aeration on February 2, 2006. Note that the levels of soluble
iron in the February 2 and 27, 2006, source-water samples were comparable at 1,159 and 855 (ig/L,
respectively.
As discussed in the Design Manual for the Removal of Arsenic from Drinking Water Supplies by Iron
Removal Process (Hoffman, et al., 2006), the use of a chemical oxidant and the point of chemical oxidant
addition are critical to optimize arsenic removal via the iron-removal process. Research has shown that
iron particles formed in the presence of soluble As(V), like the case of preoxidation with NaMnO4, had
more capacity to remove soluble As(V) than pre-formed iron particles, as with the case of aeration.
Edwards (1994) reported that pre-formed iron hydroxides only reached one-fifth to one-sixth of the
maximum adsorption density for iron hydroxides formed in the presence of soluble As(V). The
differences in adsorption densities were attributed to certain mechanisms (i.e., strictly surface adsorption
versus adsorption and co-precipitation). Lytle and Snoeyink (2003) also observed that arsenic removal
was lower with pre-formed iron solids, as opposed to the ideal case of oxidizing both soluble Fe(II) and
As(III) at the same time. Consequently, the oxidation of iron and arsenic should occur at the same time to
achieve optimal arsenic removal.
The February 27, 2006, speciation results also showed that even without the use of NaMnO4, most soluble
As(III) in the filter influent was oxidized to soluble As(V) within the gravity filter, with the soluble As(V)
concentration elevated to 22.4 |o,g/L and particulate arsenic reduced to <0.01 |o,g/L in the filter effluent.
The amount of soluble As(V) in the filter effluent suggested that a portion of the soluble As(V) formed in
the filter, along with that already existing in the filter influent, was removed, presumably by attaching to
the iron solids accumulating in the filter. Removal of soluble As(V) also was observed during all but one
(on February 27, 2007) subsequent speciation event, with removal rates ranging from 13% to 51% and
averaging 26%. These soluble As(V) removal rates were lower than the 57% As(V) removal rate
38
-------
achieved on February 2, 2006, following NaMnO4 preoxidation. Adsorption of As(V) on pre-formed iron
solids, as discussed above, probably explains why the removal rates were lower.
The gravity filter was effective in removing particulate iron, as indicated by less than the MDL of iron in
the filter effluent throughout the performance evaluation study (except for one sampling event on June 6,
2006). The gravity filter removed approximately 59% of particulate arsenic, leaving only 4.2 Lig/L (on
average) in the filter effluent (Table 4-6). Because soluble As(III) was oxidized to soluble As(V) in the
filter under natural conditions and due to elevated manganese levels in the filter effluent in the presence
of high TOC, it was decided to continue the study without NaMnO4 addition (see Section 4.5.1.3).
In summary, after the use of NaMnO4 was discontinued, the average soluble As(III) and soluble As(V)
concentrations following the detention tank (AC) were 26.2 and 10.4 |o,g/L, respectively (Table 4-6). The
average soluble As(III) level after the gravity filter (AF) decreased to 1.6 |o,g/L, and As(V) increased to
26.4 ng/L. The aeration step in the AERALATER® unit converted approximately 26% (on average) of
As(III) to As(V). Across the gravity filter, approximately 94% of As(III) was oxidized to As(V) via
naturally occurring microbial-mediated processes. As shown by Figure 4-14, approximately 34% (on
average) of total arsenic was removed by the gravity filter, lower than the 60% from the single sampling
event on February 2, 2006, with NaMnO4 addition. Arsenic exiting the gravity filter was removed by the
AD-33 media in the APU-300 system.
The arsenic breakthrough curves for the two adsorption vessels and the entire system are presented in
Figure 4-14, with total arsenic concentrations plotted against throughput in BV at the IN, AC, AF, TA,
TB, and TT locations. As expected, arsenic concentrations in the adsorption vessel effluent (TA, TB, and
TT) increased gradually (except for one measurement at approximately 10,000 BV), with total arsenic
concentrations measured below the MCL of 10 Lig/L during the 1-year performance evaluation study.
60
so
_ 40 -
30
o
o
20
10-
-IN
-AC
-AF
-TA
-TB
As MCL = 10 ng/L
10 15
Bed Volume of Water Treated (x 1000)
Figure 4-14. Total Arsenic Concentrations vs. Throughput
39
-------
At the end of the study, the total arsenic concentration was 9.8 (ig/L in system effluent (February 27,
2007). The city took two more compliance samples after the end of the study, with total arsenic
concentrations at 7.0 (ig/L at around 22,400 BV on March 19, 2007, and at 11 (ig/L at around 26,300 BV
on May 29, 2007. Extrapolating from the average daily production of 52,418 gpd, the arsenic
breakthrough above 10 (ig/L most likely occurred at 25,300 BV, which was only 31% of the vendor's
projected capacity of 82,500 BV (Table 4-3).
As discussed above, the total arsenic removal efficiency of the gravity filter was reduced from
approximately 60% to 34% after stopping NaMnO4 injection, which shifted the burden of arsenic removal
from the gravity filter to the downstream adsorption vessels. The vendor's estimate of 82,500 BV was
based on expected removal across the gravity filter of 30% to 50%, which would result in influent arsenic
concentrations of 22 to 31 |o,g/L to the APU-300 treatment system. This design basis is comparable to the
26.4-|o,g/L As(V) concentration from the filter effluent (without NaMnO4 addition). Therefore, the
discrepancy observed in media run length would have been caused by factors such as competing ions (like
total phosphorous) in the source water, which were not accounted for in the vendor's run-length estimate
(see Section 4.5.1.6).
Microbial-Mediated As(III) Oxidation. Since the NaMnO4 addition ended, soluble As(III) was
unexpectedly oxidized to soluble As(V) in the gravity filter, apparently via certain natural pathways.
Figure 4-15 shows the biogeochemical cycle of arsenic as it is transformed between the As(III) and As(V)
states in the environment. This transformation often is mediated by microbial activities. Several
researchers have reported the presence of As(III)-oxidizing bacteria in surface and groundwater
(Oremland and Stolz, 2003; Battaglia-Brunet et al., 2002; Hambsch et al., 1995), with over 30 strains of
microorganisms identified. These microorganisms are categorized in two groups (heterotrophic arsenite
oxidizers [FŁAOs] and chemolithoautotrophic arsenite oxidizers [CAOs]) based on the pathways involved
in arsenite oxidation. The term heterotroph means that the microbe uses organic carbon substrates for its
biomass growth, while the term autotroph means that the microbe uses inorganic carbon (e.g. CO2) for its
biomass growth. These two types of microorganisms oxidize As(III) through the following mechanisms
(Oremland and Stoltz, 2003):
• Heterotrophic Arsenite Oxidizers. The FŁAOs primarily oxidize As(III) as a detoxification
reaction that converts As(III) to As(V) at the cell membrane. This helps inhibit its entry into
the cellular structure. This reaction does not create energy or biomass for the FŁAO microbe.
• Chemolithoautotrophic Arsenite Oxidizers. The CAOs use As(III) as an electron donor to
reduce oxygen or nitrate and use the energy to fix CO2 into biomass. The term
chemolithoautotroph refers to the microbe that uses chemical reactions for energy ("chemo")
and uses inorganic electron donors ("litho") to fix CO2 into biomass ("autotroph").
Under a separate task order, researchers at EPA and Battelle observed similar naturally-occurring As(III)
oxidation processes in a gravity sand filter following aeration at the Greene County Southern Plant
(GCSP) in Beaver Creek, OH. Source water at the plant contained 45.9 and 2,280 |o,g/L of total arsenic
and iron, both existing almost entirely in the soluble form. Upon aeration and filtration, As(III)
concentrations were reduced from 37.2 |og/L (on average) in the filter influent to 1.2 |og/L (on average) in
the filter effluent. As(V) removal across the filter bed was 77%, much higher than the 26% observed at
the Stewart, MN facility without NaMnO4 preoxidation (Wang, 2006a). Higher As(V) removal at the
GCSP was likely due to the lower pH value at 7.5, which is more favorable for As(V) adsorption onto
iron solids, and the <10 |o,g/L of total phosphorous, which eliminated a source of competing species for
As(V) removal. At the GCSP, the oxidation of As(III) occurred concurrently with nitrification in the
filter bed, which converted almost 100% of the 1.2 mg/L of NH3 (as N) (on average) in the filter influent
to NO3" in the filter effluent (Wang, 2006a; Lytle et al., 2007). However, nitrification
40
-------
CH2O
Mn (IV), ^
N03,
Fe (III)
CO
2 As (V)
2 As (III)
CH2O
Anaerobic
CO,
Figure 4-15. Biogeochemical Cycle of Arsenic (Oremland et al., 2002)
was determined not to be directly responsible for As(III) oxidation under an internally funded research
project at Battelle. The results of this study will be further discussed under Section 4.5.1.5.
At the Stewart, MN site, the average As(III) levels declined from 26.2 |o,g/L in the filter influent to 1.6
Hg/L in the filter effluent. The reduction of DO concentrations from 5.0 mg/L after aeration to 2.6 mg/L
after the filter suggested that oxygen was the most likely electron donor in a biologically mediated
process and that aerobic conditions persist throughout the filter. A portion of DO removal also might be
attributed to the nitrification process that occurred, although this process was shown to be unrelated to the
As(III) oxidation at the GCSP, as described below in Section 4.5.1.5.
4.5.1.2 Iron. Figure 4-16 presents total iron concentrations measured across the treatment train.
Total iron concentrations in source water ranged from 993 to 1,491 |o,g/L and averaged 1,188 |o,g/L,
existing primarily in the soluble form at 922 |o,g/L (on average). The average soluble iron and soluble
arsenic concentrations in source water corresponded to a ratio of 23:1, which was just over the 20:1 target
ratio for more effective arsenic removal (Sorg, 2002). As discussed above, relatively high pH values
and/or high concentrations of competing anion and TOC in source water might affect the arsenic-removal
capacity of the natural iron solids.
Aeration alone in the AERALATER® unit was sufficient to accomplish complete Fe(II) oxidation.
Soluble iron concentrations after aeration and the detention tank were <25 |o,g/L; complete conversion of
soluble iron to particulate iron was achieved. The AERALATER® filter was effective in removing
particulate iron, reducing the iron concentrations to be close to or below the MDL of 25 |o,g/L over the 1-
year study period. No particulate iron breakthrough was observed from the gravity filter, indicating
adequate filtration rate and filter backwash frequency.
Following the APU-300 adsorption vessels, iron levels remained at <25 |o,g/L, with the exception of one
outlier taking place on July 25, 2006, when total iron (as particulate) appeared to break through from
Vessels A and B at 337 and 524 |o,g/L, respectively. It was not clear what had caused the elevated iron
concentrations observed. The system appeared to operate properly at the time, with differential pressure
across the system remaining as low as 1 psi. On the subsequent sampling events, the total iron levels
from Vessels A and B returned to <25 |o,g/L.
41
-------
1,600
1,400
1,200
1,000
m
u
c
o
o
800
600
400
200
-IN
-AC
-AF
-TA
-TB
Fe SMCL = 300 ng/L
10
. O—&A-OAAAOA/
15
20
25
Bed Volume of Water Treated (x 1000)
Figure 4-16. Total Iron Concentrations vs. Bed Volumes
4.5.1.3 Manganese. Manganese concentrations in source water ranged from 19.6 to 44.3 |o,g/L and
averaged 23.6 |og/L. Manganese existed primarily in the soluble form at an average concentration of 24.0
Hg/L. Manganese removal is discussed below for treatment system performance, both with and without
NaMnO4 addition. For the first sampling event on February 2, 2006, the NaMnO4 feed pump was
operational and a total manganese concentration of 541 |o,g/L was measured after preoxidation, aeration,
and detention. The total manganese concentration following the gravity filter (AF) was elevated at 127
Hg/L, existing entirely as soluble manganese. The presence of elevated soluble manganese in the filter
effluent was unexpected, because the amount of NaMnO4 added was very close to the stoichiometric
dosage of 0.42 mg/L (as Mn) for the February 2, 2006, source water, and should have been completely
consumed and converted to MnO2 solids during the preoxidation step.
The detection of "soluble manganese" was probably caused by the presence of high TOC levels in source
water. It is possible that the "soluble manganese" exiting the filter was present in the colloidal form that
penetrated through the gravity filter and the 0.45-(im disc filters during speciation sampling. Researchers
have reported that high levels of dissolved organic matter (DOM) in source water can form fine colloidal
MnO2 particles not filterable by conventional gravity or pressure filters (Knocke et al., 1991). Similar
observation also was made at another EPA arsenic demonstration site at Sauk Centre, MN, where
elevated levels of "soluble manganese" up to 1,062 (ig/L were observed following the contact tank and
Macrolite® pressure filters as the KMnO4dosage was progressively decreased from 3.8 to 1.4 mg/L (as
Mn) due to concerns with overdosing. (Note that similar to the Stewart, MN system, permanganate was
used for the Sauk Centre, MN system to preoxidize as much as 23 and 2,691 (ig/L of As(III) and Fe(II),
respectively, due to the presence of 4.0 mg/L of TOC.) At Sauk Centre, "soluble manganese" eventually
was reduced to as low as 2.5 (ig/L as the KMnO4dosage was increased to 5.6 mg/L (as Mn). Increasing
the KMnO4 dosage probably helped diminish the effect of DOM on Mn(II) oxidation and helped form
more filterable MnO2 particles (Shiao, et al., 2007).
42
-------
At Stewart, elevated manganese concentrations in the gravity filter effluent occurred only with NaMnO4
addition, which took place for about a week. The colloidal manganese present in the gravity filter effluent
was removed by AD-33 media, with its concentration reduced from 127 to 3.7 |o,g/L on February 2, 2006.
Had NaMnO4 addition continued at the same dose rate as on February 2, 2006, the elevated colloidal
manganese levels in the filter effluent could become an issue for media performance. At other EPA
demonstration sites with pre-chlorination, such as Rollinsford, NH, elevated manganese levels were found
to coat and foul AD-33 media (Cumming et al., 2009), resulting in early arsenic breakthrough and short
media run length. The impact of elevated manganese levels on AD-33 media should be minimal because
they occurred for only a very short duration.
After the February 2, 2006, sampling event, when the NaMnO4 feed pump lost prime, manganese levels
after the detention tank (AC) decreased significantly to those in raw water (e.g., at 21 |o,g/L by the next
sampling event on February 14, 2006 [see Figure 4-17]). Total Mn levels exiting the AERALATER®
filter continued to be somewhat elevated relative to filter influent levels during most of the sampling
events throughout the study. From February 14 to April 4, 2006, some manganese was removed by AD-
33 media, and the removal continued for approximately 3,400 BV. Since then, the effluent values have
become equal to, or somewhat higher than, the influent values. These results suggest that AD-33 media
had only a limited capacity for Mn removal (present as Mn2+ ions). As discussed in Section 4.5.1.1, the
NaMnO4 addition was not resumed during the remainder of the performance evaluation study.
200
150
o
.fc 100
o
u
Peak = 541 ng/L at 700
Bed Volumes
10 15
Bed Volume of Water Treated (x 1000)
20
25
Figure 4-17. Total Manganese Concentrations vs. Bed Volumes
4.5.1.4 pH, DO, and ORP. pH values of source water ranged from 7.4 to 8.2 and averaged 7.9. pH
values increased slightly from an average value of 7.9 at the wellhead to 8.3 after the AERALATER®
filter. Aeration probably contributed to this increase in pH. DO levels averaged 1.2 mg/L in source water
and increased to an average value of 5.0 mg/L after aeration. DO concentrations decreased by about 48%
to an average value of 2.6 mg/L across the gravity filter. The aerobic biological processes responsible for
As(III) oxidation and nitrification processes might have consumed some of the DO in the filter influent
43
-------
(Sawyer, et al., 2003). The average DO levels after the APU-300 system were 2.7 mg/L, essentially the
same as those going into the adsorption system. ORP levels averaged 216 mV in source water and 207
mV after aeration and the detention tank. Again, probably due to the biological processes, ORP readings
decreased to 186 mV (on average) after the gravity filter. ORP levels averaged 173 mV in the combined
effluent of the APU-300 system.
4.5.1.5 Ammonia and Nitrate. Twenty-nine sampling events took place for ammonia and 30 for
nitrate during the 1-year performance evaluation study. In source water, ammonia concentrations ranged
from 1.0 to 1.9 mg/L (as N) and averaged 1.6 mg/L (as N); nitrate concentrations were consistently less
than the MDL of 0.05 mg/L (as N). Following aeration and detention, ammonia concentrations remained
essentially unchanged, although up to 0.3 mg/L (as N) concentration differences were observed between
the IN and AC sampling locations. Nitrate concentrations also remained unchanged following aeration
and detention, with all measurements less than 0.05 mg/L (as N), except for one outlier of 0.1 mg/L (as
N) measured at the AC location on December 12, 2006.
Figure 4-18 shows the decreases in ammonia concentration and increases in nitrate concentration across
the gravity filter and AD-33 adsorption vessels versus volume throughput in bed volumes by the system.
After treating 3,100 BV of water (or 69 days after system startup on January 18, 2006), some ammonia
began to be removed by the gravity filter and AD-33 adsorption vessels. Decreases in ammonia
concentration across the gravity filter ranged from 0 to 0.6 mg/L (as N) and averaged 0.3 mg/L (as N).
Decreases in ammonia concentration across the AD-33 adsorption vessels ranged from 0 to 1 mg/L (as N)
and averaged 0.3 mg/L (as N). Nitrate concentrations remained below 0.05 mg/L (as N) until 4,400 BV
of water had been treated (or 97 days after system startup), and then started to increase. Increases in
nitrate concentration across the gravity filter ranged from 0 to 1.5 mg/L (as N) and averaged 0.2 mg/L (as
N). Increases in nitrate concentration across the AD-33 adsorption vessels ranged from 0 to 1.6 mg/L (as
N) and averaged 0.3 mg/L (as N). The concentration changes between ammonia and nitrate across the
gravity filter and AD-33 adsorption vessels appear to follow a stoichiometric relationship.
The decreasing ammonia and DO concentrations and increasing nitrate concentrations indicate that
nitrification was occurring within the gravity filter and AD-33 adsorption vessels approximately 69 to 97
days into system operation. The 69-day timeframe was based on the observation of ammonia removal,
while the 97-day timeframe was based on detectable levels of nitrate in the gravity filter effluent.
Under the aerobic conditions in the AERALATER® filter, nitrifiers, including Nitrosomonas and
Nitrobacters, can convert ammonia to nitrite and then to nitrate following the reaction equations (Sawyer
et al., 2003) as follows:
2NH3 + 3O2 = 2NO2- +2H+ + 2H2O [Nitrosomonas]
2NO2" + O2 = 2NO3 [Nitrobacter]
Through research efforts funded separately by EPA and Battelle, researchers have observed similar
nitrification processes occurring in gravity filters at the GCSP in Beaver Creek, OH, that have a similar
treatment train (i.e., aeration and gravity filtration) to the Stewart, MN, system (Lytle et al., 2007; Wang,
2006). In addition, As(III) to As(V) oxidation also was observed, possibly through biologically-mediated
processes. Based on laboratory column tests conducted with filtered source water and filter media
obtained from the GCSP, it was observed that As(III) oxidation continued to occur even after the
nitrification processes had been completely inhibited by lowering the influent pH values to < 5.0 (Clark et
al., 1977). This suggests that nitrification is not necessary for the microbial-mediated As(III) oxidation to
occur (Wang et al., 2006). The same study also showed that, after the filter media in the column had been
44
-------
Ammonia and Nitrate Concentrations Changes Across the Gravity Filter
Ammonia (Cone, at AF - Cone, at AC)
Nitrate (Cone, at AF - Cone, at AC)
Bed Volume of Water Treated (x 1000)
Ammonia and Nitrate Concentrations Changes Across the Adsorption Vessel A
Ammonia (Cone, at TA - Cone, at AF)
Nitrate (Cone, at TA - Cone, at AF)
Bed Volume of Water Treated (x 1000)
Ammonia and Nitrate Concentrations Changes Across the Adsorption Vessel B
Ammonia (Cone, at TB - Cone, at AF)
Nitrate (Cone, at TB - Cone, at AF)
Bed Volume of Water Treated (x 1000)
Figure 4-18. Decreases/Increases in Ammonia/Nitrate Across AERALATER® Filter
and AD-33 Adsorption Vessels
45
-------
sterilized with HgCl2, the pathways responsible for As(III) oxidation apparently were disrupted, thus
allowing As(III) to break through from the column, with the same amount of As(III) measured in both the
column influent and effluent. Furthermore, because significant nitrification was not observed for 97 days
compared to 40 days for As(III) oxidation, it was very likely that oxygen, instead of nitrate, was the
electron acceptor for the microbial-mediated As(III) oxidation process. As discussed above, there was a
48% DO removal rate across the gravity filter, with approximately 2.6 mg/L of O2 in the filter effluent,
suggesting the persistence of aerobic conditions through the filter.
4.5.1.6 Other Water Quality Parameters. Alkalinity, fluoride, sulfate, silica, TOC, temperature, and
hardness levels remained consistent across the treatment train and were not significantly affected by the
treatment process (Table 4-7). TOC levels were elevated at 6.4 mg/L in source water, and no significant
change was observed across the treatment train. Although high TOC levels might have contributed to the
oxidant demand, they did not appear to have been adsorbed onto iron solids. The orthophosphate level in
the source water was 0.02 mg/L (as PO4) based on historic sampling, and was not considered by the
vendor as a factor impacting the media run length, which was estimated at 82,500 BV. However, the
study results indicate that total phosphorus (as P) was present in source water at levels that lowered the
effectiveness of arsenic removal in both the gravity filter and APU-300 treatment systems. Total P
decreased from an average concentration of 301 |o,g/L (or 0.92 mg/L as PO4) in source water to an average
concentration of 112 and 37.2 ng/L, following the AERALATER® filter and APU-300 system,
respectively. Turbidity also decreased from 6.5 nephelometric turbidity units (NTU) in source water to
<1.0 NTU after the AERALATER® filter and APU-300 system.
4.5.2 Backwash Wastewater Sampling. Table 4-8 presents the analytical results of 13 monthly
backwash wastewater sampling from the two AERALATER® filter cells. pH values of the backwash
wastewater ranged from 7.8 to 8.1 and averaged 7.9; TDS concentrations ranged from 378 to 468 mg/L
and averaged 423 mg/L; TSS concentrations ranged from 28 to 260 mg/L and averaged 87 mg/L. TSS
levels appeared to decline after switching from grab to composite sampling, using a sump pump, on
September 20, 2006.
Concentrations of total arsenic, iron, and manganese ranged from 168 to 844 (ig/L (averaged 343 (ig/L),
17 to 111 mg/L (averaged 38 mg/L), and 34 to 109 (ig/L (averaged 57 (ig/L), respectively, with the
majority existing as particulate. Assuming that 87 mg/L of TSS (i.e., the averaged TSS) was produced in
7,619 gal of backwash wastewater from the AERALATER® filter (Table 4-5), approximately 5.5 Ib of
solids would have been discharged during each backwash event. Based on the average particulate metal
data (311 (ig/L of particulate arsenic, 38 mg/L of particulate iron, and 34 (ig/L of particulate manganese),
the solids discharged would have been composed of 0.02 Ib of arsenic (0.4% by weight), 2.4 Ib of iron
(43.6 % by weight), and 0.002 Ib of manganese (0.04% by weight).
Backwash solids samples were collected on February 28, 2007, from both AERALATER® filter cells.
The samples were analyzed for total metals; results are presented in Table 4-9. Arsenic, iron, and
manganese levels in the solids averaged 0.94 mg/g (or 0.09%), 154 mg/g (or 15.4%), and 0.2 mg/g (or
0.02%), respectively. Based on the backwash wastewater samples collected on February 28, 2007, the
averaged concentrations of particulate arsenic, iron, and manganese were 206, 22,646, and 15.2 (ig/L,
respectively. Assuming that 79.5 mg/L of TSS (i.e., the averaged TSS in the backwash wastewater
samples collected on February 28, 2007) were produced in 7,619 gal of backwash wastewater from the
AERALATER® filter (Table 4-5), arsenic, iron, and manganese contents in the solids were calculated to
be 0.26, 28.5, and 0.02%, respectively. While the calculated manganese content was equivalent to that
based on the backwash solids analysis, the calculated arsenic and iron contents were about three and two
times higher, respectively. The degree of inconsistency is considered reasonable, considering that the
results are from two independent sampling systems (wastewater and backwash solids).
46
-------
Table 4-8. AERALATER® Filter Backwash Wastewater Sampling Results
Sampling Event
No.
1
2
3
4
5
6
7
8
9
10
11
12
13
Date
03/01/06(a)
03/22/06
04/12/06
05/31/06
06/28/06
07/26/06
08/23/06
09/20/06
10/25/06
11/29/06
01/03/07
01/17/07
02/28/07
BW1
Backwash Filter Cell No. 1
in
S.U.
8.1
8.0
8.0
8.0
7.9
7.9
7.9
7.9
7.8
7.8
7.9
7.9
8.0
CO
Q
1—
mg/L
426
432
428
454
430
428
468
454
422
432
392
382
422
CO
CO
mg/L
92
104
28
130
214
126
144
54
54
60
50
58
71
i
U)
-------
During the 1-year performance evaluation study, the APU-300 adsorption vessels were backwashed four
times using the treated water. One set of backwash wastewater samples were collected from the sample
ports located in the backwash effluent discharge lines from each vessel on January 17, 2007. Table 4-10
summarizes the analytical results. The backwash wastewater averaged at 7.9 for pH, 380 mg/L for TDS,
54 mg/L for TSS, 201 (ig/L for total arsenic, 21 mg/L for total iron, and 35 (ig/L for total manganese.
Soluble arsenic concentrations averaged 27.3 |og/L, which was higher than that in the treated water used
for backwash. Therefore, desorption of arsenic from the adsorptive media might occur during backwash.
Soluble iron concentration averaged 55.2 |o,g/L, which also was higher than that in the treated water (<25
Hg/L). In general, the results measured from Vessels A and B were consistent among one another.
Assuming 5,926 gal of backwash wastewater generated from two APU-300 vessels (the average
backwash wastewater generated per backwash event; see Table 4-5) and 54 mg/L of TSS (see Table 4-
10), approximately 2.7 Ib of solids would have been discharged during each backwash event. Based on
the average particulate metal data (174 (ig/L of particulate arsenic, 21.2 mg/L of particulate iron, and 14.3
(ig/L of particulate manganese), the solids discharged would have been composed of 3.9 g of arsenic
(0.32% by weight), 476 g of iron (39.6 % by weight), and 0.32 g of manganese (0.03% by weight).
Table 4-10. APU-300 Adsorption Vessels Backwash Wastewater Sampling Results
Sampling Event
Sample Location
Backwash Vessel No. 1
Backwash Vessel No. 2
Date
1/17/2007
1/17/2007
M
S.U.
7.9
7.9
^
0
H
mg/L
382
378
H
mg/L
58
50
^^
eS
Ł
<
Hg/L
209
193
^
,.0
3
i
<
Hg/L
25.1
29.5
?
^2
3
•c
K =*
Hg/L
184
164
Ł^v
eS
2
o
U.
Hg^
22,112
20,386
/ N
A
3
i
OJ
ti.
Hg/L
66.8
43.6
^3
-g
c/
=
Hg/L
37.1
33.6
3
o
=
Hg/L
20.5
21.6
4.5.3 Distribution System Water Sampling. Distribution system water samples were collected to
determine if water treated by the arsenic removal system would impact the lead, copper, and arsenic
levels and other water chemistry in the distribution system. Prior to system startup, baseline distribution
water samples were collected on February 16, March 16, April 13, and May 18, 2005. Since system
startup, distribution water sampling continued monthly at the same three locations until January 9, 2007.
The samples were analyzed for pH, alkalinity, arsenic, iron, manganese, lead, and copper; Table 4-11
presents the results.
The main differences observed between the baseline samples and samples collected after system startup
were decreases in arsenic concentration at each of the three sampling locations. Arsenic concentrations
were reduced from apre-startup average of 31.2 to a post-startup average of 6.1 |og/L. In Figure 4-19,
arsenic concentrations measured in the distribution system water were compared to those in the treatment
system effluent. In general, total arsenic concentrations in distribution system water were higher than
those in the treatment system effluent. Nonetheless, the concentrations in distribution system water were
still below the MCL for all samples, except for the first sample collected at DS3. Desorption and
resuspension of arsenic previously accumulated on the distribution pipe surface most likely are the
reasons for higher arsenic concentration in the distribution system.
48
-------
Table 4-11. Distribution System Sampling Results
Sampling Event
No.
BL1
BL2
BL3
BL4
1
2
3
4
5
6
7
8
9
10
11
12
Date
02/16/05
03/16/05(b)
04/13/05
05/18/05
02/22/06
03/21/06
04/18/06
05/16/06
06/13/06
07/11/06
08/15/06
09/12/06
10/10/06
11/07/06
12/12/06
01/09/07
DS1
0)
H
C
o
1
M
sS
55
hr
9.0
8.5
8.0
9.0
8.5
7.8
8.5
9.0
M
a.
S.U.
7.6
7.7
7.7
7.7
7.9
7.8
8.0
7.8
Alkalinity
mg/L
436
466
424
428
416
406
438
409
G«
<
Hg/L
27.0
29.3
30.1
30.5
7.8
2.1
3.5
3.1
&
Hg/L
337
404
206
169
<25
<25
<25
<25
I
Hg/L
21.4
21.6
26.5
21.3
10.7
20.9
26.4
26.9
.a
a<
Hg/L
0.8
0.9
1.1
0.5
0.1
0.1
0.1
0.1
U
Hg/L
130
159
202
105
85.4
35.9
70.4
103
Homeowner did not collect sample
8.0
9.0
8.3
7.5
9.0
8.0
9.0
7.6
7.7
7.7
7.6
7.7
7.4
7.7
419
413
451
444
443
426
453
3.2
5.2
5.0
6.6
7.2
9.0
7.4
<25
<25
<25
<25
<25
<25
<25
24.9
27.6
25.4
25.0
24.6
26.6
22.2
0.1
0.3
0.3
0.3
0.1
0.3
0.2
91.7
135
138
145
83.2
125
128
DS2
1>
H
B
o
1
M
sS
55
hr
8.5
10.0(a)
10.0
9.4W
7.0
9.5
9.5
9.8
7.0
7.5
0.1(c)
6.5
8.8
10.0
9.0
8.7
M
a.
S.U.
7.6
7.5
7.7
7.9
7.9
7.8
7.9
7.8
7.7
7.7
7.7
7.7
7.6
7.7
7.6
7.8
Alkalinity
mg/L
414
433
424
428
416
410
438
405
433
415
400
446
437
425
428
440
5«
<
Hg/L
37.2
37.1
31.8
33.8
9.9
4.2
4.1
3.5
4.1
3.9
5.6
4.9
6.9
8.5
8.5
7.3
&
Hg/L
1,317
548
174
193
<25
<25
62.8
<25
<25
<25
<25
<25
<25
<25
<25
<25
S
Hg/L
23.2
23.0
25.9
21.4
11.7
18.0
22.9
28.2
30.2
23.2
28.5
25.5
27.4
25.0
26.1
19.0
A
&
^g/L
19.8
0.1
0.2
0.
0.
0.
0.
0.
0.
0.4
0.1
0.1
0.2
0.1
0.1
0.1
u
Hg/L
0.5
56.3
125
195
179
131
154
106
338
292
241
144
344
345
161
316
-------
Table 4-11. Distribution System Sampling Results (Continued)
Sampling Event
No.
BL1
BL2
BL3
BL4
1
2
o
J
4
5
6
7
8
9
10
11
12
Date
02/16/05
03/16/05tb)
04/13/05
05/18/05
02/22/06
DS3
Stagnation Time
hr
9.0
8.5
8.0
8.3
9.8
03/21/06 8.0
04/18/06
05/16/06
06/13/06
07/11/06
08/15/06
09/12/06
10/10/06
11/07/06
12/12/06
01/09/07
8.8
11.5
8.0
6.3
6.7
12.5
7.8
8.5
10.0
9.0
M
s.u.
7.6
7.7
7.7
7.7
7.9
7.9
7.9
7.7
7.6
7.5
7.7
7.7
7.6
7.6
7.5
7.7
Alkalinity
mg/L
418
433
446
428
420
419
434
405
429
415
425
458
461
445
440
438
t«
•<Ł
Hg/L
27.2
29.8
29.7
30.4
17.8
9.9
4.7
4.7
3.7
3.7
4.7
5.8
6.5
7.0
7.5
6.2
0)
u.
Hg/L
311
197
427
230
<25
250
249
<25
203
45.4
52.1
<25
232
<25
170
138
|
Hg/L
23.6
20.1
25.7
22.3
17.5
20.2
25.3
29.4
30.1
28.4
33.2
29.6
32.4
28.3
33.5
27.0
.a
a.
Hg/L
1.0
0.5
1.4
0.5
<0.1
0.4
0.3
<0.1
<0.1
0.1
0.2
<0.1
0.2
<0.1
0.1
<0.1
u
Hg/L
130
143
162
118
103
177
222
184
226
203
185
187
217
201
188
208
(a) Estimate provided by the homeowner.
(b) DS 1 sampled on 03/22/05 .
(c) Not first draw sample.
Action levels: 15 |ig/L Pb and 1.3 mg/L Cu. BL = baseline sampling; DS =
distribution sampling
-------
Measured pH values ranged from 7.4 to 8.0; alkalinity levels ranged from 400 to 466 mg/L (as CaCO3).
Iron concentrations measured at DS1 and DS2 were <25 |og/L, except for one sample collected at DS2 on
April 18, 2006. Iron concentrations measured at DS3 ranged from <25 to 250 |og/L and averaged
116 |og/L, which was significantly higher than that measured at the system effluent (<25 |og/L). Some
corrosion products might have been washed out of the distribution system during DS3 sampling.
Manganese concentrations averaged 23.0 and 25.2 |og/L before and after system startup, respectively,
which were similar to the levels in the treatment system effluent.
The average lead level was 2.7 jog/L in the baseline samples and 0.2 |o,g/L in the samples taken after
system startup; these concentrations were significantly lower than the action level of 15 |og/L. The
average copper level was 127 |o,g/L in the baseline samples and 177 |o,g/L in the samples taken after
system startup; these concentrations also were significantly lower than the action level of 1,300 |og/L.
The treatment did not appear to impact the lead and copper levels in the distribution system.
5.0
10.0 15.0
Bed Volume of Water Treated (x 1000)
20.0
25.0
4.6
Figure 4-19. Comparsion of Total Arsenic Concentrations in Distribution System Water
and APU-300 System Effluent
System Cost
The cost of the treatment 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 task required tracking capital cost for the
equipment, site engineering, and installation and the O&M cost for media replacement and disposal,
replacement parts, chemical supply, electricity consumption, and labor. These costs do not include the
building cost or instrumentation and control upgrades installed by the City of Stewart.
51
-------
4.6.1 Capital Cost. The capital investment for equipment, site engineering, and installation for the
250-gpm treatment system was $367,838. The equipment cost was $273,873 (or 74.4% of the total
capital investment), which included $125,555 for a Siemens Type II AERALATER® system; $126,482
for a skid-mounted APU-300 system; $17,952 for ancillary equipment; and $3,884 for freight (as shown
in Table 4-12). The Siemens' Type II AERALATER® system included a 11-ft-diameter steel unit (which
was composed of an aerator, a fan, a detention tank, and a four-cell filter for a total of $77,000); process
valves and piping ($32,060); instrumentation and controls ($7,420); 190 ft3 of sand ($8,400); and other
materials ($675). The APU-300 system included two skid-mounted fiberglass vessels ($45,360); process
valves and piping ($19,460); instrumentation and controls ($20,860); 128 ft3 of AD-33 media ($32,000 or
$250/ft3); and $8,802 for other materials.
The engineering cost included the cost for the preparation and submission of an engineering submittal
package, including a process flow diagram of the treatment system, mechanical drawings of the treatment
equipment, a schematic of the equipment footprint as discussed in Section 4.3.1, and attainment of the
required state permit for implementing the system. The engineering cost was $16,520, which was 4.5%
of the total capital investment.
The installation cost included the equipment and labor to unload and install the AERALATER® and skid-
mounted APU-300 systems, perform piping tie-ins and electrical work, and load and backwash the media
in both AERALATER® filter and AD-33 adsorption vessels (see Section 4.3.3). The installation was
performed by AdEdge and a local subcontractor. The installation cost was $77,445, or 21.1% of the total
capital investment.
The capital cost of $367,838 was normalized to $l,471/gpm ($1.02 per gpd) of design capacity, using the
system's rated capacity of 250 gpm (or 360,000 gpd). The capital cost also was converted to an
annualized cost of $34,720/yr using a capital recovery factor (CRF) of 0.09439 based on a 7% interest
rate and a 20-yr return period. Assuming that the system operated 24 hr/day, 7 day/wk at the design
flowrate of 250 gpm to produce 131,400,000 gal/yr, the unit capital cost would be $0.26/1,000 gal.
During the performance evaluation study, the system operated only 4.7 hr/day and produced an average of
19,132,570 gal of water in one year (Table 4-4), so the unit capital cost increased to $1.80/1,000 gal at
this reduced rate of use. These calculations did not include the building construction cost.
4.6.2 Operation and Maintenance Cost. The O&M cost included items such as AD-33 media
replacement and disposal, replacement parts, chemicals, electricity, and labor (see Table 4-13). During
the 1-year study period, there was no chemical cost incurred because NaMnO4 addition was discontinued.
There was no replacement-part cost incurred either because all parts were covered under a 1-year
warranty. Although AD-33 media was not replaced during the 1-year study period, the media
replacement cost would represent the majority of the O&M cost. The vendor estimate was $41,370 for
replacing 128 ft3 media in the two APU-300 vessels. This cost includes new media, gravel underbedding,
labor, travel, equipment rental, and freight. Although the vendor did not provide a cost breakdown for
media profiling and disposal, such cost was assumed to be included in the total cost estimate.
Because media replacement did not take place during the study, the cost per 1,000 gal of water treated
was calculated as a function of projected media run length, using the vendor cost estimate (see Figure 4-
20). At the end of the performance evaluation study, the total arsenic concentration was 9.8 (ig/L in the
system effluent on February 27, 2007. Two more compliance samples were taken by the city after the end
of the study, with total arsenic concentrations at 7.0 (ig/L at about 22,400 BV on March 19, 2007, and at
11 (ig/L at about 26,300 BV on May 29, 2007. Extrapolating from the average daily production of 52,418
gpd, the arsenic breakthrough above 10 (ig/L most likely would occur at 25,300 BV, which was only 31%
52
-------
Table 4-12. Capital Investment Cost for Siemens and AdEdge Treatment Systems
Description
Quantity
Cost
% of Capital
Investment Cost
Equipment
Siemens Type II AERALATER®
11-ft-diameter Steel, Epoxy -Lined Unit, Including
Aerator, Fan, Detention Tank, and Filter
Filter Media (ft3)
Process Valves and Piping
Instrumentation and Controls
Additional Sample Taps
Subtotal
1
190
1
1
1
$77,000
$8,400
$32,060
$7,420
$675
$125,555
—
-
-
-
-
-
AdEdge APU-300 System
63 -in-diameter Fiberglass Vessels on Skid
AD-33 Media (ft3)
Gravel Underbedding
Process Valves and Piping
Instrumentation and Controls
Totalizer for Backwash Line
1-Year O&M Support, O&M Manuals
Subtotal
2
128
1
1
1
2
-
$45,360
$32,000
$1,540
$19,460
$20,860
$2,422
$4,840
$126,482
-
-
-
-
-
-
-
-
Ancillary Equipment
KMnO4 Feed System
Booster Pumps
Motor Controls/MCC/HOA for Pumps
In-Line Mixer
Subtotal
1
2
1
1
$4,192
$6,580
$6,850
$330
$17,952
-
-
-
-
Freight
Freight-AD33 Media (Ib)
Freight-Filter Media (Ib)
Freight-System (Ib)
Freight-Ancillary Equipment
Subtotal
Equipment Total
4,460
10,000
26,000
1
-
$780
$680
$2,112
$312
$3,884
$273,873
-
-
-
-
74.4%
Engineering
Vendor Labor
Vendor Travel
Vendor Material
Subcontractor Labor
Subcontractor Travel
Subcontractor Material
Engineering Total
-
-
-
-
-
-
$4,534
$2,480
$98
$8,400
$420
$588
$16,520
4.5%
Installation
Vendor Labor
Vendor Travel
Subcontractor Mechanical
Subcontractor Electrical
Subcontractor Other Labor
Installation Total
Total Capital Investment
-
-
-
-
-
-
-
$7,920
$3,800
$39,985
$21,890
$3,850
$77,445
$367,838
21.1%
100%
53
-------
of the vendor-projected capacity of 82,500 BV (Table 4-3). The short media life corresponded to a high
medial replacement cost of $1.71/1,000 gal (Figure 4-20).
A comparison of the electrical bills before and after system startup was conducted to estimate the
electrical cost. Before the treatment plant was installed, the utility bill totaled $3,643 from January 1 to
December 31, 2005. After the treatment plant was operational, the utility bill totaled $5,125 from January
1 to December 31, 2006. Therefore, the incremental electricity cost was approximately $0.08/1,000 gal.
Electricity was used mainly for operating the AERALATER® unit.
Routine labor activities for O&M consumed 10 min/day for operational readings and 31 min/week for one
manual backwash event. This is equivalent to 101 min/week (or 1.7 hr/week) on a 7 day/week basis. The
estimated labor cost is $0.08/1,000 gal of water treated, based on this time commitment and a labor rate of
$16.33/hr.
Table 4-13. O&M Cost for City of Stewart, Minnesota Treatment System
Cost Category
Volume Processed (kgal)
Value
20,441
Media Replacement andDis
Media Cost ($/ftj)
Total Media Volume (ft3)
Media Replacement Cost ($)
Gravel Underbedding Cost ($)
Labor, Travel, and Equipment Cost ($)
Freight ($)
Subtotal
Media Replacement and Disposal Cost
($/l,000 gal)
$250
128
$32,000
$1,650
$6,940
$780
$41,370
See Figure 4-20
Assumptions
Through February 28, 2007
posal
Vendor quote
Two vessels
Vendor quote
Vendor quote
Vendor quote
Vendor quote
Vendor quote
Based on media run length at 10 |ag/L
arsenic breakthrough
Replacement Parts
Replacement Parts Cost ($)
Labor and Travel Cost ($)
Equipment Replacement Cost ($/l,000 gal)
$0.00
$0.00
$0.00
Cost related to parts replacement was
negligible during 1-year study period
-
-
Chemical Usage
Chemical Cost ($)
$0.00
No chemicals required after NaMnO4
oxidation discontinued.
Electricity
Estimated Incremental Electricity Cost ($/yr)
Incremental Cost ($/l,000 gal)
$1,482
$0.08
Based on utility bills
Annual system throughput = 19,133 kgal
Labor
Average Weekly Labor (hr)
Annual Labor Cost ($/yr)
Labor Cost ($/l, 000 gal)
Total O&M Cost/1,000 gal
1.7
$1,444
$0.08
See Figure 4-20
10 min/day, plus 3 1 min manual backwash
Average labor rate = 16.33/hr
Annual system throughput = 19,133 kgal
-
54
-------
o
o
$4.00
$3.75
$3.50
$3.25
$3.00
$2.75
$2.50
$2.25
$2.00
$1.75
$1.50
$1.25
$1.00
$0.75
$0.50
$0.25
$0.00
O&M cost
- Media replacement cost
0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150
Media Working Capacity, Bed Volumes (xlOOO)
Figure 4-20. Media Replacement and O&M Cost for AERALATER8
and APU-300 Systems at Stewart, Minnesota
55
-------
5.0 REFERENCES
Battaglia-Brunet, F., M.C. Dictor, and F. Garrido. 2002. "An Arsenic(III)-Oxidizing Bacterial
Population: Selection, Characterization, and Performance in Reactors." J. Applied Microbiology,
93(4): 656-67.
Battelle. 2004. Quality Assurance Project Plan for Evaluation of Arsenic Removal Technology.
Prepared under Contract No. 68-C-00-185, Task Order No. 0029, for U.S. Environmental
Protection Agency, National Risk Management Research Laboratory, Cincinnati, OH.
Chen, A.S.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.
Clark, J.W., W. Viessman, and M.J. Hammer. 1977. Water Supply and Pollution Control. Third
Edition. Thomas Y. Crowell Company, Inc., New York, NY.
Cumming, L.J., A.S.C. Chen, and L. Wang. 2009. Arsenic Removal from Drinking Water by Adsorptive
Media. EPA Demonstration Project at Rollinsford, NH: Final Performance Evaluation Report.
EPA/600/R-09/017. U.S. Environmental Protection Agency, National Risk Management
Research Laboratory, Cincinnati, OH.
Edwards, M. 1994. "Chemistry of Arsenic Removal during Coagulation and Fe-Mn Oxidation."
JAWWA, 86(9): 64.
Edwards, M., S. Patel, L. McNeill, H. Chen, M. Frey, A.D. Eaton, RC. Antweiler, and H.E. Taylor.
1998. "Considerations in As Analysis and Speciation." JAWWA, 90(3): 103-113.
EPA. 2003. "Minor Clarification of the National Primary Drinking Water Regulation for Arsenic."
Federal Register, 40 CFRPart 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 Part 9, 141, and 142.
Ghurye, G. and D. Clifford. 2001. Laboratory Study on the Oxidation of Arsenic III to Arsenic V.
EPA/600/R-01/021. U.S. Environmental Protection Agency, National Risk Management
Research Laboratory, Cincinnati, OH.
Hambsch, B., B. Raue, and H.J. Brauch. 1995. "Determination of Arsenic(III) for the Investigation of
the Microbial Oxidation of Arsenic(III) to Arsenic(V)." Acta Hydrochimica et Hydrobiologica,
23(4): 166-172.
Hoffman, G., D. Lytle, T.J. Sorg, A.S.C. Chen, and L.Wang. 2006. Design Manual. Removal of
Arsenic from Drinking Water Supplies by Iron Removal Process. EPA/600/R-06/030. U.S.
Environmental Protection Agency, National Risk Management Research Laboratory, Cincinnati,
OH.
56
-------
Knocke, W. R, J.E. Van Venschoten, M.J. Kearney, A.W. Soborski, and D.A. Reckhow. 1991.
"Kinetics of Manganese and Iron Oxidation by Potassium Permanganate and Chlorine Dioxide."
JAWWA, 83(6): 80-87.
Lytle, D.A., and V.L. Snoeyink. 2003. "The Effect of Dissolved Inorganic Carbon on the Properties of
Iron Colloidal Suspensions." J. Water Supply: Res. and Tech. AQUA, 52(3): 165-180.
Lytle, D.A., T. J. Sorg, C. Muhlen, L. Wang, M. Rahrig, and K. French. 2007. "Biological Nitrification in
a Full-scale and Pilot-scale Iron Removal Drinking Water Treatment Plant." J. Water Supply:
Res. and Tech. AQUA, 56(2): 125-136.
Oremland, R.S., S.E. Hoeft, J.M. Santini, N. Bano, R.A. Hollibaugh, and J.T. Hollibaugh. 2002.
"Anaerobic Oxidation of Arsenite in Mono Lake Water and by a Facultative, Arsenite-Oxidizing
Chemoautotroph, Strain MLHE-1." Applied and Environmental Microbiology, 68(10): 4795-
4802.
Oremland, R.S. and J.F. Stolz. 2003. "The Ecology of Arsenic." Science, 300(5): 939-944.
Oxenham, J., Chen, A.S.C, and L. Wang. 2005. Arsenic Removal from Drinking Water by Adsorptive
Media. EPA Demonstration Project at Rollinsford, NH: Six-Month Evaluation Report.
EPA/600/R-05/116. U.S. Environmental Protection Agency, National Risk Management
Research Laboratory, Cincinnati, OH.
Sawyer, C.N., P.L. McCarty, and G.F. Parkin. 2003. Chemistry for Environmental Engineering and
Science. 5th Edition. McGraw-Hill Companies, Inc., New York, NY.
Shiao, H.T., W.E. Condit, and A.S.C. Chen. 2007. Arsenic Removal from Drinking Water by Iron
Removal. EPA Demonstration Project at Big Sauk Lake Mobile Home Park in Sauk Centre, MN.
Six Month Evaluation Report. EPA/600/R-07/048. U.S. Environmental Protection Agency,
National Risk Management Research Laboratory, Cincinnati, OH.
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.
Wang, L. 2006. Long-Term Performance of Full-Scale Water Treatment Systems at Greene County,
Ohio Evaluation of Treatment Technology for the Removal of Arsenic from Drinking Water.
Letter Report for Contract No. 68-C-00-185, Task Order No. 20. U.S. Environmental Protection
Agency, National Risk Management Research Laboratory, Cincinnati, OH.
Wang, L., A.S.C. Chen, L. N. Tong, and A. Paolucci. 2006. Evaluation ofAs(III) Oxidation via
Microbial-MediatedProcesses. Report preapred under Battelle's Internal Research and
Development Program for Fiscal Year 2006, Columbus, OH.
57
-------
APPENDIX A
OPERATIONAL DATA
-------
Table A-l. US EPA Arsenic Demonstration Project at Stewart, MN - Daily System Operation Log Sheet
Week
No.
1
2
3
4
5
6
7
8
9
10
Day of
Week
Mon
Tue
Wed
Thu
Fri
Sat
Sun
Mon
Tue
Wed
Thu
Fri
Sat
Sun
Mon
Tue
Wed
Thu
Fri
Sat
Sun
Mon
Tue
Wed
Thu
Fri
Sat
Sun
Mon
Tue
Wed
Thu
Fri
Sat
Sun
Mon
Tue
Wed
Thu
Fri
Sat
Sun
Mon
Tue
Wed
Thu
Fri
Sat
Sun
Mon
Tue
Wed
Thu
Fri
Sat
Sun
Mon
Tue
Wed
Thu
Fri
Sat
Sun
Mon
Tue
Wed
Thu
Fri
Sat
Sun
Date
01/30/0607:35
01/31/0607:00
02/01/06 07:30
02/02/06 06:30
02/03/0608:10
02/04/0608:15
02/05/06 08:50
02/06/0608:15
02/07/0607:10
02/08/06 08:35
02/09/06 08:00
02/10/0609:10
02/11/0608:10
02/12/0608:15
02/13/0607:15
02/14/0607:30
02/15/0607:30
02/16/0607:35
02/17/0608:00
02/18/0609:00
02/19/0608:30
02/20/06 09:00
02/21/06 08:00
02/22/06 08:45
02/23/06 07:30
02/24/06 07:50
02/25/0608:15
02/26/06 09:30
02/27/06 06:30
02/28/0610:15
03/01/0607:15
03/02/0608:15
03/03/06 07:45
03/04/06 08:30
03/05/06 08:30
03/06/06 06:40
03/07/06 07:00
03/08/06 08:00
03/09/06 07:50
03/10/0607:30
03/11/0610:00
03/12/0609:15
03/13/0607:10
03/14/0606:30
03/15/0607:45
03/16/0607:15
03/17/0607:50
03/18/0606:45
03/19/0607:30
03/20/06 07:30
03/21/06 07:00
03/22/06 10:00
03/23/06 07:30
03/24/06 07:30
03/25/06 07:30
03/26/06 09:30
03/27/06 07:30
03/28/0606:15
03/29/06 06:55
03/30/06 08:30
03/31/06 06:55
04/01/0611:30
04/02/06 09:40
04/03/06 07:30
04/04/06 07:30
04/05/06 07:30
04/06/0607:10
04/07/06 07:30
04/08/06 07:00
04/09/06 07:30
Op
Hours
Mrs
NA
.1
.9
.0
.2
.8
.0
.0
.1
.9
.0
.7
.9
.9
.8
.9
.7
.9
.9
.8
.0
.0
.8
.8
.8
.9
.8
.7
.7
.0
.9
.9
.9
.4
.7
.2
.1
.0
.0
.9
.8
.4
.4
.8
.7
.3
.6
.8
.6
.9
.9
.8
.3
.8
.0
.0
.0
.0
.1
.0
.0
.6
.0
.1
.0
.3
.1
.9
.7
.7
Well 3
Gallon
Usage
gal
NA
12,800
44,400
23,000
39,000
21,700
22,700
23,700
1 1 ,800
22,900
23,100
20,300
22,000
1 1 ,000
22,400
21,900
20,800
22,600
1 1 ,500
21,500
23,000
24,100
22,300
21,100
21,100
1 1 ,600
34,000
20,700
20,500
23,900
22,400
21,800
22,200
16,800
10,480
33,620
24,900
23,200
23,400
21,900
22,100
16,800
16,500
21,700
20,500
16,200
44,000
20,700
20,300
22,300
10,800
21,700
16,100
19,700
23,500
22,900
23,000
23,700
12,300
23,400
23,100
30,700
22,700
23,800
23,700
25,600
12,300
22,600
21,000
19,900
Average
Flow rate
gpm
NA
194
190
192
203
201
189
198
179
201
193
199
193
204
207
192
204
198
213
199
192
201
206
195
195
215
202
203
201
199
196
191
195
200
103
255
198
193
195
192
205
200
196
201
201
208
204
192
211
196
200
201
206
182
196
191
192
198
186
195
193
197
189
189
198
186
186
198
206
195
Op
Hours
Mrs
NA
.0
.1
.7
.8
.5
.9
.8
.7
.7
.3
.6
.0
.6
.9
.0
.1
.1
.6
.7
.0
.0
.2
.2
.4
.9
.0
.5
.8
.9
.9
.7
.8
.7
.8
.7
.9
.8
.7
.1
.9
.1
.9
.0
.0
.0
.0
.0
.1
.1
.9
.1
.4
.8
.6
.1
.1
.8
.7
.8
.0
.7
.9
.9
.9
.8
.8
.9
.0
.3
Well 4
Gallon
Usage
gal
NA
0.0
23,900
19,800
12,600
37,300
21,500
20,500
19,300
20,000
15,300
28,300
17,400
21,000
22,200
22,300
12,200
22,800
21,600
26,700
22,100
21,600
23,900
14,200
27,400
20,900
22,300
16,600
19,200
22,100
10,400
31,400
20,100
19,200
14,480
26,320
21,300
21,100
19,400
12,700
33,700
22,500
21,500
22,100
1 1 ,200
22,400
21,500
1 1 ,300
23,600
23,000
21,500
22,800
27,500
20,000
18,400
23,100
12,700
20,800
19,400
20,000
1 1 ,400
31,400
10,200
21,300
21,400
21,000
19,600
33,100
1 1 ,400
25,300
Average
Flowrate
gpm
NA
NA
0
94
5
4
9
0
9
6
6
1
0
5
5
6
5
1
8
2
84
0
1
7
0
3
6
84
78
94
3
94
6
8
34
8
7
5
0
2
94
9
9
84
7
7
9
8
7
3
9
1
1
5
2
3
2
3
0
5
0
94
9
7
8
94
1
0
0
3
AERALATER
Backwash
Yes/No
No
Yes
No
Yes
No
No
No
No
No
No
No
No
No
No
No
No
No
No
Yes
No
No
No
No
No
No
Yes
No
No
No
No
Yes
No
No
No
No
No
No
No
No
Yes
No
No
No
No
No
Yes
No
No
No
No
No
Yes
No
No
No
No
No
No
No
No
Yes
No
No
No
No
No
Yes
No
No
No
Vessel A
Flow Rate
gpm
92
92
92
NA
NA
92
92
NA
NA
NA
NA
NA
88
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
82
NA
NA
NA
NA
NA
NA
NA
0
NA
NA
NA
NA
NA
NA
NA
NA
103
NA
NA
NA
NA
NA
NA
104
NA
NA
NA
101
NA
NA
104
NA
NA
NA
NA
NA
NA
91
NA
NA
NA
NA
NA
Vessel A
Service
Totalizer
gal
282,600
288,114
318,183
337,773
365,977
384,714
406,021
426,860
442,802
463,684
480,412
502,250
532,156
541,319
563,172
585,122
601,420
623,167
639,994
661,073
682,816
704,779
726,872
742,579
763,415
778,326
797,262
814,936
835,831
856,567
872,014
971,158
992,853
1,000,897
1,031,633
1,054,674
1,007,817
1,100,817
1,119,988
1,140,465
1,163,976
1,181,234
1,203,680
1,226,174
1,242,433
1,259,485
1,291,047
1,307,759
1,330,633
1,350,435
16,886
40,391
56,671
79,796
99,025
123,300
144,965
168,523
185,370
208,268
226,074
254,724
272,088
295,966
316,719
344,520
361,684
385,893
403,723
427,592
Cumulative
Bed
Volumes
BV
590
602
665
705
764
804
848
892
925
968
1,003
1,049
1,111
1,131
,176
,222
,256
,302
,337
,381
,426
,472
,518
,551
,594
,626
,665
,702
,746
,789
,821
,028
,074
,090
,155
,203
,105
,299
,339
,382
,431
,467
,514
,561
,595
,631
,697
,731
,779
,821
,856
,905
,939
,987
,027
,078
,123
,173
,208
,256
,293
,353
,389
,439
,482
,540
,576
,627
,664
,714
Vessel B
Flow Rate
gpm
91
91
91
NA
NA
91
91
NA
NA
NA
NA
NA
70
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
78
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
98
NA
NA
NA
NA
NA
NA
103
NA
NA
NA
98
NA
NA
103
NA
NA
NA
NA
NA
NA
86
NA
NA
NA
NA
NA
Vessel B
Service
Totalizer
gal
275,090
280,488
309,822
328,931
355,460
372,554
391,931
410,436
424,496
443,020
457,596
476,125
492,894
507,614
525,767
544,109
557,855
576,526
591,015
609,618
628,969
648,622
668,540
682,802
702,735
717,060
735,356
752,279
772,329
792,207
806,985
924,367
945,645
961,433
983,608
1,006,104
1,029,016
,051,005
,069,653
,089,401
,112,105
,128,707
,150,212
,171,717
,187,240
,203,462
,233,215
,248,624
,269,754
,291,692
16,535
39,553
55,448
77,927
96,604
120,078
140,960
163,674
179,924
201,978
219,063
246,480
263,018
285,813
305,684
332,196
348,582
371,649
388,618
411,311
Cumulative
Bed Volumes
BV
575
586
647
687
742
778
819
857
887
925
956
994
,029
,060
,098
,136
,165
,204
,234
,273
,314
,355
,396
,426
,468
,498
,536
,571
,613
,655
,685
,931
,975
2,008
2,054
2,101
2,149
2,195
2,234
2,275
2,323
2,357
2,402
2,447
2,480
2,514
2,576
2,608
2,652
2,698
2,732
2,780
2,814
2,861
2,900
2,949
2,992
3,040
3,074
3,120
3,155
3,213
3,247
3,295
3,336
3,392
3,426
3,474
3,510
3,557
Combined
Backwash
Totalizer
gal
0
0
0
0
64
64
64
6^7
64
64
64
64
64
64
64
64
64
64
64
64
64
6^7
64
64
,4 2
,4 2
,4 2
,4 2
3,472
,472
,472
,472
,472
,472
,472
,472
,472
,472
,472
,472
,472
,472
,472
,472
,472
,472
,472
,472
,472
3,. 72
-------
Table A-l. US EPA Arsenic Demonstration Project at Stewart, MN - Daily System Operation Log Sheet (Continued)
>
Week
No.
11
12
13
14
15
17
18
19
20
Day of
Week
Mon
Tue
Wed
Thu
Fri
Sat
Sun
Mon
Tue
Thu
Fri
Sat
Sun
Mon
Tue
Wed
Thu
Fri
Sat
Sun
Mon
Tue
Wed
Thu
Sat
Sun
Mon
Tue
Wed
Thu
Fri
Sat
Sun
Mon
Tue
Wed
Fri
Sat
Sun
Mon
Tue
Wed
Thu
Fri
Sat
Sun
Mon
Tue
Wed
Thu
Fri
Sat
Sun
Mon
Tue
Wed
Thu
Fri
Sat
Sun
Mon
Tue
Wed
Thu
Fri
Sat
Sun
Date
04/10/0608:00
04/11/0607:30
04/12/0607:30
04/13/0607:00
04/14/0607:00
04/15/0607:50
04/16/0610:30
04/17/0607:15
04/18/0606:45
04/20/06 07:30
04/21/06 07:30
04/22/06 08:00
04/23/06 08:00
04/24/06 07:30
04/25/06 09:30
04/26/06 07:30
04/27/06 07:30
04/28/06 06:50
04/29/06 08:50
04/30/0610:00
05/01/06 07:30
05/02/06 08:30
05/03/06 07:30
05/04/06 07:30
05/06/06 09:00
05/07/06 07:30
05/08/06 07:30
05/09/06 08:35
05/10/0607:30
05/11/0607:10
05/12/0607:00
05/13/0606:00
05/14/0607:50
05/15/0608:10
05/16/0607:30
05/17/0607:30
05/19/0607:30
05/20/06 07:45
05/21/0607:15
05/22/06 07:45
05/23/06 07:30
05/24/06 08:00
05/25/06 07:00
05/26/06 07:00
05/27/06 07:30
05/28/06 09:00
05/29/06 09:30
05/30/06 07:00
05/31/0610:00
06/01/0607:30
06/02/06 07:00
06/03/06 07:30
06/04/06 08:30
06/05/0607:15
06/06/0607:15
06/07/06 07:30
06/08/06 08:00
06/09/06 08:00
06/10/0609:00
06/11/0609:00
06/12/0607:30
06/13/0607:00
06/14/0607:10
06/15/0607:20
06/16/0607:00
06/17/0607:30
06/18/0607:45
Op
Hours
Mrs
1.7
1.8
1.0
2.5
1.5
2.3
1.9
0.9
2.6
2.1
2.0
2.2
1.1
2.3
3.2
2.3
2.2
1.8
1.8
1.8
1.9
1.6
1.4
2.0
2.1
2.0
2.4
1.6
2.0
2.0
2.9
1.8
1.8
2.0
2.1
2.1
2.0
1.0
1.9
2.6
2.3
3.0
2.1
3.1
3.3
2.5
2.8
3.8
3.2
3.4
3.1
3.2
3.6
2.2
2.7
2.1
3.1
3.3
2.8
2.0
2.0
2.4
2.9
1.9
2.2
1.4
3.6
Well 3
Gallon
Usage
gal
20,400
22,700
11,200
30,700
18,400
27,700
22,100
11,500
30,700
24,600
22,400
24,700
12,400
25,800
34,700
25,400
25,100
21,700
21,300
21,200
2,700
38,800
16,900
23,800
24,100
24,000
28,500
19,500
23,600
23,900
34,300
20,300
19,800
23,000
23,500
22,800
22,400
11,600
23,100
30,000
25,700
33,300
23,100
35,500
36,500
28,100
31,200
40,600
35,800
39,400
36,300
38,600
42,600
25,400
32,000
24,100
37,100
39,000
33,400
23,500
23,800
29,500
33,000
23,500
23,700
16,000
39,800
Average
Flowrate
gpm
200
210
187
205
204
201
194
213
197
195
187
187
188
187
181
184
190
201
197
196
24
404
201
198
191
200
198
203
197
199
197
188
183
192
187
181
187
193
203
192
186
185
183
191
184
187
186
178
186
193
195
201
197
192
198
191
199
197
199
196
198
205
190
206
180
190
184
Op
Hours
Mrs
2.2
2.2
2.0
1.9
1.9
2.0
2.2
2.1
2.5
1.4
1.5
1.9
1.8
1.8
1.8
1.8
2.0
2.5
2.2
2.3
2.2
2.2
2.0
2.1
2.0
2.2
2.1
1.9
2.2
2.1
1.1
1.9
1.7
2.0
1.9
2.0
2.0
3.7
2.2
3.1
1.8
1.9
2.0
1.7
2.0
3.2
2.0
2.2
3.5
2.3
2.7
3.8
5.8
1.6
3.7
2.1
3.5
3.3
2.1
2.1
2.2
2.3
4.1
2.1
2.6
2.9
2.3
Well 4
Gallon
Usage
gal
23,700
24,000
22,200
21,800
17,500
19,600
24,600
22,600
28,800
16,300
16,600
21,400
20,900
20,100
21,100
20,900
22,300
27,800
23,800
25,300
24,800
23,700
22,800
22,900
23,000
23,700
23,500
22,700
22,300
23,200
12,100
22,600
18,400
24,100
21,000
22,700
23,000
42,000
23,200
35,100
21,200
21,000
22,400
19,600
22,300
36,700
22,700
25,800
39,000
NA
NA
40,800
62,000
16,300
40,100
22,700
38,300
34,400
23,500
23,600
23,800
24,900
43,700
23,400
30,700
32,200
25,900
Average
Flowrate
gpm
80
82
85
91
54
63
86
79
92
94
84
88
94
86
95
94
86
85
80
83
88
80
90
82
92
80
87
99
69
84
83
98
80
01
84
89
92
89
76
89
96
84
87
92
86
91
89
95
86
NA
NA
79
78
70
81
80
82
74
87
87
80
80
78
86
97
85
88
AERALATER
Backwash
Yes/No
No
No
Yes
No
No
No
No
No
No
No
No
No
No
No
No
No
Yes
No
No
No
No
No
No
Yes
No
No
No
No
No
Yes
No
No
No
No
No
No
Yes
No
No
No
No
No
Yes
No
No
No
No
No
Yes
No
No
No
No
No
No
No
No
Yes
No
No
No
No
No
Yes
No
No
No
Vessel A
Flow Rate
gpm
NA
86
NA
NA
NA
NA
NA
NA
99
NA
NA
81
NA
NA
89
NA
NA
NA
NA
NA
95
99
NA
NA
NA
NA
NA
97
NA
NA
NA
NA
NA
NA
91
NA
NA
NA
NA
NA
NA
88
NA
NA
NA
NA
NA
82
NA
NA
NA
NA
NA
NA
NA
NA
NA
95
NA
NA
NA
95
NA
NA
NA
NA
NA
Vessel A
Service
Totalizer
gal
450,987
474,931
493,225
517,323
523,009
542,452
567,273
585,508
611,098
660,342
683,851
706,158
725,593
749,547
778,661
802,861
824,698
847,633
871,240
895,354
917,086
939,085
962,737
986,918
1,036,423
1,061,862
1,086,995
1,112,269
1,134,854
1,159,259
1,178,114
1,197,538
1,220,387
1,244,073
1,267,795
1,291,456
1,338,976
1,361,859
1,386,140
1,419,448
1,443,607
1,468,540
1,482,626
1,517,547
1,545,234
1,578,619
1,608,016
1,640,353
NA
1,710,216
1,743,905
1,781,981
1,838,375
1,859,633
1,896,516
1,920,563
1,956,062
1,993,408
2,018,564
2,042,466
2,066,750
2,092,388
2,133,607
2,157,420
2,180,588
2,205,255
2,238,756
Cumulative
Bed
Volumes
BV
3,762
3,813
3,851
3,901
3,913
3,954
4,005
4,043
4,097
4,200
4,249
4,295
4,336
4,386
4,447
4,497
4,543
4,591
4,640
4,691
4,736
4,782
4,831
4,882
4,985
5,038
5,091
5,144
5,191
5,242
5,281
5,322
5,369
5,419
5,468
5,518
5,617
5,665
5,716
5,785
5,836
5,888
5,917
5,990
6,048
6,118
6,179
6,247
NA
6,393
6,463
6,542
6,660
6,705
6,782
6,832
6,906
6,984
7,037
7,086
7,137
7,191
7,277
7,327
7,375
7,427
7,496
Vessel B
Flow Rate
gpm
NA
83
NA
NA
NA
NA
NA
NA
95
NA
NA
98
NA
NA
85
NA
NA
NA
NA
NA
92
96
NA
NA
NA
NA
NA
94
NA
NA
NA
NA
NA
NA
90
NA
NA
NA
NA
NA
NA
86
NA
NA
NA
NA
NA
81
NA
NA
NA
NA
NA
NA
NA
NA
NA
95
NA
NA
NA
96
NA
NA
NA
NA
NA
Vessel B
Service
Totalizer
gal
433,564
456,451
473,753
496,698
528,566
559,093
581,256
598,270
622,415
668,800
691,123
712,438
730,996
753,989
782,073
804,962
825,800
847,801
870,491
893,704
914,659
935,859
958,668
982,085
1,029,783
1,054,119
1,078,116
1,102,292
1,123,876
1,147,312
1,165,472
1,184,169
1,206,143
1,229,005
1,251,991
1,274,925
1,321,122
1,343,381
1,367,029
1,399,559
1,423,099
1,447,450
1,470,959
1,495,225
1,522,268
1,554,878
1,583,589
1,615,279
NA
1,683,814
1,716,927
1,754,425
1,810,012
1,831,041
1,867,421
1,891,195
1,926,446
1,963,490
1,988,497
2,012,255
2,036,415
2,061,868
2,102,710
2,126,215
2,149,056
2,173,412
2,206,522
Cumulative
Bed Volumes
BV
,603
,651
,687
,735
,802
,866
,912
,947
,998
,095
,141
,186
,225
,273
,331
,379
,423
,469
,516
,564
,608
,653
,700
,749
,849
,900
,950
,000
,045
,094
,132
,171
,217
,265
,313
,361
,457
,504
,553
,621
,670
,721
,770
,821
,877
,945
,005
,072
NA
,215
,284
,362
,478
,522
,598
,648
,721
,799
,851
,901
,951
,004
,090
,139
,186
,237
,306
Combined
Backwash
Totalizer
gal
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
-------
Table A-l. US EPA Arsenic Demonstration Project at Stewart, MN - Daily System Operation Log Sheet (Continued)
>
Week
No.
22
23
25
26
27
28
29
30
Day of
Week
Mon
Tue
Wed
Fri
Sat
Sun
Mon
Tue
Wed
Thu
Fri
Sat
Sun
Mon
Wed
Thu
Fri
Sat
Sun
Mon
Tue
Wed
Fri
Sat
Sun
Mon
Tue
Wed
Thu
Fri
Sun
Mon
Tue
Wed
Thu
Sat
Sun
Mon
Tue
Wed
Thu
Fri
Sat
Sun
Mon
Tue
Wed
Thu
Fri
Sat
Sun
Mon
Tue
Wed
Thu
Fri
Sat
Sun
Mon
Tue
Wed
Thu
Fri
Sun
Date
06/19/0607:30
06/20/06 09:30
06/21/06 07:00
06/23/06 07:30
06/24/06 09:30
06/25/06 08:40
06/26/06 07:00
06/27/06 07:30
06/28/06 07:30
06/29/06 07:00
06/30/06 07:00
07/01/06 08:00
07/02/06 08:00
07/03/06 07:00
07/05/06 07:00
07/06/06 07:00
07/07/06 07:30
07/08/06 07:00
07/09/06 08:30
07/10/0607:30
07/11/0607:30
07/12/0607:45
07/14/0607:30
07/15/0607:30
07/16/0608:00
07/17/0607:30
07/18/0607:30
07/19/0607:00
07/20/06 07:00
07/21/06 07:00
07/23/0610:10
07/24/0607:15
07/25/06 07:00
07/26/06 06:20
07/27/06 07:00
07/29/0608:15
07/30/06 08:45
07/31/06 06:30
08/01/06 09:30
08/02/06 07:30
08/03/06 07:45
08/04/06 06:30
08/05/0610:00
08/06/06 09:30
08/07/06 07:00
08/08/06 07:00
08/09/06 07:00
08/10/0607:00
08/11/0606:45
08/12/0616:00
08/13/0618:00
08/14/0609:00
08/15/0608:00
08/16/0607:15
08/17/0607:45
08/18/0607:00
08/19/0607:30
08/20/06 08:30
08/21/06 07:30
08/22/06 07:00
08/23/06 07:30
08/24/06 07:30
08/25/06 07:00
08/27/06 09:00
Op
Hours
Mrs
1.2
3.5
2.4
3.3
5.3
0.2
2.2
2.9
2.2
1.8
2.1
2.1
3.3
2.1
3.1
2.7
3.5
2.4
5.3
2.6
4.4
3.3
2.8
4.3
3.0
3.6
5.2
2.0
3.5
3.2
2.8
3.3
2.8
3.6
4.2
2.6
4.3
2.0
4.0
3.3
3.4
2.2
2.3
2.2
2.4
2.9
3.1
4.3
3.3
1.4
1.5
2.3
3.0
2.3
3.7
1.6
3.1
1.7
3.1
3.1
2.4
2.2
Well 3
Gallon
Usage
gal
13,500
38,800
26,600
38,700
38,500
25,900
26,100
34,900
25,000
22,100
25,000
24,700
40,000
23,500
36,400
31,300
41,900
27,100
61,700
29,400
50,700
36,100
30,900
50,000
33,600
38,100
55,100
22,000
36,400
36,500
31,400
36,400
33,400
43,200
50,300
32,600
48,000
22,500
43,800
37,500
37,700
25,000
25,600
24,500
26,600
32,300
33,800
47,600
37,400
17,800
17,600
25,000
36,100
24,200
42,200
18,400
33,400
19,900
36,400
34,500
26,700
25,100
Average
Flowrate
gpm
188
185
185
195
121
2158
198
201
189
205
198
196
202
187
196
193
200
188
194
188
192
182
184
194
187
176
177
183
173
190
187
184
199
200
200
209
186
188
183
189
185
189
186
186
185
186
182
184
189
212
196
181
201
175
190
192
180
195
196
185
185
190
Op
Hours
Mrs
1.9
2.0
1.9
3.3
4.5
2.1
2.3
2.2
2.6
3.6
7.9
4.0
2.4
3.1
3.4
3.4
3.4
5.6
2.6
4.4
7.7
3.4
2.9
5.0
2.1
5.8
3.3
2.1
4.8
3.2
2.9
5.9
4.0
6.6
5.7
4.6
5.4
2.0
2.1
3.6
2.1
2.2
2.2
2.1
3.3
2.1
2.0
1.5
3.4
1.7
2.3
1.7
4.2
1.7
2.4
2.8
1.5
2.7
3.0
2.0
2.0
1.2
Well 4
Gallon
Usage
gal
19,600
25,200
20,800
36,800
48,600
22,600
24,200
24,000
27,800
40,200
87,300
43,000
25,400
32,600
36,100
36,600
35,400
57,700
27,600
46,900
77,400
36,800
31,800
51,200
24,400
63,500
36,700
23,400
50,800
32,500
28,700
58,700
42,400
73,800
59,800
48,500
57,600
22,500
24,200
40,800
23,400
24,600
25,200
24,400
36,700
23,100
23,600
16,300
37,600
18,000
25,300
18,100
45,600
19,800
27,100
30,400
18,000
29,000
31,900
22,500
22,500
13,400
Average
Flowrate
gpm
72
10
82
86
80
79
75
82
78
86
84
79
76
75
77
79
73
74
72
77
78
68
80
83
71
94
82
85
86
76
69
65
66
77
86
75
76
78
88
92
89
86
86
91
94
85
83
97
81
84
76
83
77
81
94
88
81
00
79
77
88
88
86
AERALATER
Backwash
Yes/No
No
No
No
No
No
No
No
No
Yes
No
No
No
No
No
No
Yes
No
No
No
No
No
Yes
No
No
No
No
No
No
No
Yes
No
No
No
Yes
No
No
No
Yes
No
No
Yes
No
No
No
No
No
No
No
Yes
No
No
No
No
No
No
Yes
No
No
No
No
Yes
No
No
No
Vessel A
Flow Rate
gpm
NA
95
NA
NA
NA
NA
NA
94
NA
NA
NA
NA
94
NA
NA
NA
85
NA
NA
NA
NA
NA
NA
80
NA
93
NA
73
83
81
NA
81
NA
NA
NA
NA
NA
NA
82
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
82
92
NA
90
NA
NA
NA
NA
NA
NA
NA
NA
NA
Vessel A
Service
Totalizer
gal
,256,658
,287,962
,312,303
,378,811
,423,121
,448,429
,474,481
,501,625
,531,793
,557,220
,616,173
,651,423
,681,050
,714,077
,786,863
,823,623
,865,948
,908,966
,953,202
,998,101
,038,652
,105,202
,156,849
,186,370
,241,639
,268,449
,320,042
,366,506
,388,565
,433,666
,506,408
,537,286
,589,635
,626,432
,678,340
,789,942
,847,814
,887,370
,931,228
,954,306
,987,471
,021,061
,050,664
,074,924
,099,546
,123,342
,152,384
,179,343
,206,219
,233,613
,270,098
,286,018
,305,719
,329,626
,366,564
,389,862
,418,264
,442,142
,467,129
,491,132
,524,068
,547,599
,571,422
,623,548
Cumulative
Bed
Volumes
BV
7,534
,599
,650
,789
,882
,934
,989
8,046
8,109
8,162
8,285
8,358
8,420
8,489
8,641
8,718
8,806
8,896
8,989
9,082
9,167
9,306
9,414
9,476
9,591
9,647
9,755
9,852
9,898
9,992
10,144
10,209
10,318
10,395
10,503
10,736
10,857
10,940
11,031
11,080
11,149
11,219
11,281
11,332
11,383
1 1 ,433
1 1 ,493
11,550
11,606
11,663
11,739
11,772
11,814
1 1 ,864
11,941
11,989
12,049
12,099
12,151
12,201
12,270
12,319
12,369
12,477
Vessel B
Flow Rate
gpm
NA
95
NA
NA
NA
NA
NA
92
NA
NA
NA
NA
92
NA
NA
NA
81
NA
NA
NA
NA
NA
78
NA
91
NA
71
77
74
NA
87
NA
NA
NA
NA
NA
NA
88
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
87
97
NA
96
NA
NA
NA
NA
NA
NA
NA
NA
NA
Vessel B
Service
Totalizer
gal
2,224,265
2,255,247
2,279,162
2,344,822
2,388,127
2,412,780
2,438,009
2,464,389
2,493,682
2,518,338
2,575,296
2,609,067
2,637,568
2,669,270
2,739,016
2,774,146
2,814,596
2,855,521
2,897,540
2,940,264
2,978,660
3,041,629
3,140,070
3,192,592
3,218,007
3,266,629
3,310,241
3,330,963
3,373,384
3,442,266
3,471,541
3,520,970
3,560,844
3,616,274
3,735,249
3,796,925
3,838,985
3,885,665
3,910,153
3,945,340
3,980,997
4,012,254
4,038,023
4,064,110
4,089,310
4,120,097
4,148,629
4,177,094
4,206,006
4,244,537
4,261,380
4,282,131
4,307,316
4,346,263
4,370,755
4,400,660
4,425,746
4,451,964
4,477,139
4,512,252
4,537,138
4,562,312
4,617,376
Cumulative
Bed Volumes
BV
7,344
7,408
7,458
7,595
7,686
7,737
7,790
7,845
7,906
7,958
8,077
8,147
8,207
8,27
8,41
8,49
8,57
8,66
8,75
8,83
8,91
9,05
9,25
9,36
9,41
9,52
9,61
9,65
9,74
9,88
9,94
10,0
10,1
10,2
10,499
10,628
10,716
10,814
10,865
10,938
11,013
11,078
11,132
11,186
11,239
11,303
11,363
11,422
11,483
11,563
11,598
11,642
11,694
11,776
11,827
11,889
11,942
11,996
12,049
12,122
12,174
12,227
12,342
Combined
Backwash
Totalizer
gal
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
-------
Table A-l. US EPA Arsenic Demonstration Project at Stewart, MN - Daily System Operation Log Sheet (Continued)
>
Week
No.
33
34
35
36
37
38
39
40
Day of
Week
Mon
Wed
Fri
Sat
Sun
Mon
Tue
Wed
Fri
Sat
Sun
Mon
Tue
Wed
Thu
Fri
Sat
Sun
Mon
Tue
Wed
Thu
Fri
Sat
Sun
Mon
Tue
Wed
Thu
Fri
Sat
Sun
Mon
Tue
Wed
Thu
Fri
Sat
Sun
Mon
Tue
Wed
Thu
Fri
Sat
Sun
Tue
Wed
Thu
Fri
Sat
Sun
Mon
Tue
Wed
Thu
Fri
Sat
Mon
Tue
Wed
Thu
Fri
Sat
Sun
Date
08/28/06 07:00
08/30/06 07:00
09/01/06 07:00
09/02/0610:00
09/03/06 08:30
09/04/0616:20
09/05/06 07:00
09/06/06 07:20
09/08/0607:15
09/09/06 09:30
09/10/0608:30
09/11/0607:30
09/12/0607:30
09/13/0607:30
09/14/0607:30
09/15/0607:30
09/16/0610:00
09/17/0608:30
09/18/0607:15
09/19/0607:45
09/20/06 07:30
09/21/06 07:00
09/22/06 07:30
09/23/06 08:45
09/24/06 08:00
09/25/06 07:30
09/26/06 07:30
09/27/06 07:30
09/28/06 07:05
09/29/06 08:30
09/30/06 08:30
10/01/0608:30
10/02/0607:30
10/03/0607:30
10/04/0607:00
10/05/0607:30
10/06/0607:30
10/07/0608:15
10/08/0608:00
10/09/0607:30
10/10/0608:00
10/11/0607:30
10/12/0607:30
10/13/0607:35
10/14/0609:00
10/15/0610:00
10/17/0607:30
10/18/0607:30
10/19/0607:30
10/20/0607:30
10/21/0608:30
10/22/0609:30
10/23/0607:30
10/24/0608:00
10/25/0607:45
10/26/0607:45
10/27/0607:30
10/28/0608:30
10/30/0607:30
10/31/0607:30
11/01/0607:30
11/02/0607:30
11/03/0608:30
11/04/0609:00
11/05/0608:00
Op
Hours
Mrs
2.4
3.1
3.6
1.9
1.9
3.1
1.0
2.0
2.2
3.8
2.3
2.3
3.2
2.3
2.1
2.1
1.3
4.2
2.2
2.8
2.9
2.4
2.2
2.3
2.4
2.7
2.7
2.5
2.5
3.0
1.9
1.9
2.2
2.0
1.9
2.1
2.0
3.2
2.2
2.3
2.1
2.8
2.5
2.1
2.8
2.5
2.3
2.3
2.3
3.7
2.3
2.4
1.7
2.8
2.0
3.3
2.2
2.2
2.3
2.4
1.4
2.2
2.1
1.0
2.1
Well 3
Gallon
Usage
gal
26,500
34,600
41,900
22,500
23,500
36,800
11,600
24,000
26,500
43,900
25,400
25,500
37,100
27,000
25,200
25,000
40,100
25,200
26,400
33,500
33,000
25,800
24,900
25,500
26,900
29,100
31,000
27,400
27,100
34,800
23,000
23,000
25,100
23,700
23,000
24,200
23,300
39,100
25,800
26,200
25,400
31,800
27,100
23,400
30,400
28,100
25,400
25,800
25,100
43,800
25,000
26,300
20,200
30,400
22,000
37,000
24,800
24,400
26,000
26,500
14,200
24,700
25,000
12,300
25,000
Average
Flowrate
gpm
184
186
194
197
206
198
193
200
201
193
184
185
193
196
200
198
514
100
200
199
190
179
189
185
187
180
191
183
181
193
202
202
190
198
202
192
194
204
195
190
202
189
181
186
181
187
184
187
182
197
181
183
198
181
183
187
188
185
188
184
169
187
198
205
198
Op
Hours
Mrs
2.3
1.6
1.8
3.8
1.3
3.9
2.6
2.4
2.3
2.1
1.5
2.5
1.4
2.4
2.6
2.6
2.2
2.3
2.4
2.4
1.5
3.3
2.8
2.7
2.2
2.2
1.9
1.9
2.1
2.5
1.2
2.5
2.6
2.6
2.4
3.0
2.2
2.3
2.4
2.4
2.3
1.6
2.0
3.5
2.0
1.9
2.0
1.2
2.1
1.0
2.1
2.0
2.0
1.9
2.0
2.0
1.3
1.9
2.1
1.6
2.6
1.1
3.7
2.3
2.2
Well 4
Gallon
Usage
gal
26,700
18,600
19,300
40,500
14,500
41,200
27,000
25,800
25,000
23,100
16,800
28,300
15,900
25,700
27,000
27,500
24,200
25,300
24,900
25,600
17,700
37,500
31,400
30,000
25,300
24,400
19,700
22,500
22,800
26,500
12,700
26,400
28,400
26,600
25,700
31,900
23,100
24,400
25,400
25,400
24,700
17,100
23,000
40,800
21,800
21,500
21,600
13,800
23,200
12,000
22,900
22,600
22,900
21,500
21,900
22,100
15,100
21,500
24,100
22,800
24,700
12,400
40,600
24,400
24,100
Average
Flowrate
gpm
93
94
79
78
86
76
73
79
81
83
87
89
89
78
73
76
83
83
73
78
97
89
87
85
92
85
73
97
81
77
76
76
82
71
78
77
75
77
76
76
79
78
92
94
82
89
80
92
84
00
82
88
91
89
83
84
94
89
91
37
58
88
83
77
83
AERALATER
Backwash
Yes/No
No
No
No
No
No
No
No
No
Yes
No
No
No
No
No
No
Yes
No
No
No
No
Yes
No
No
No
No
No
No
No
Yes
No
No
No
No
No
No
No
Yes
No
No
No
No
No
Yes
No
No
No
No
No
Yes
No
No
No
No
No
Yes
No
No
No
No
No
No
Yes
No
No
No
Vessel A
Flow Rate
gpm
NA
NA
NA
NA
NA
NA
75
NA
NA
NA
NA
90
NA
NA
NA
NA
NA
NA
NA
NA
NA
94
89
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
66
NA
NA
NA
NA
NA
NA
NA
NA
NA
82
82
NA
NA
NA
NA
NA
77
NA
NA
NA
NA
NA
Vessel A
Service
Totalizer
gal
4,649,404
4,704,979
4,754,716
4,783,164
4,803,906
4,842,202
4,859,118
4,885,510
4,935,085
4,960,553
4,978,709
5,030,173
5,058,919
5,084,510
5,110,226
5,134,156
5,158,965
5,184,212
5,213,280
5,238,085
5,264,714
5,289,585
5,317,432
5,372,295
5,397,300
5,421,918
5,446,642
5,469,349
5,489,679
5,514,331
5,540,988
5,616,794
5,641,709
5,667,122
5,692,665
5,718,486
5,743,486
5,767,870
5,792,876
5,814,027
5,842,318
5,863,478
5,905,041
5,926,979
5,950,583
5,969,846
5,993,082
6,014,351
6,034,892
6,060,136
6,082,981
6,108,243
6,126,056
6,149,901
6,197,559
6,218,629
6,240,430
6,247,805
6,273,152
6,290,878
6,314,727
Cumulative
Bed
Volumes
BV
12,531
12,647
12,751
12,811
12,854
12,934
12,969
13,025
13,128
13,181
13,219
13,327
13,387
13,440
13,494
13,544
13,596
13,648
13,709
13,761
13,817
13,869
13,927
14,041
14,093
14,145
14,197
14,244
14,286
14,338
14,394
14,552
14,604
14,657
14,710
14,764
14,817
14,867
14,920
14,964
15,023
15,067
15,154
15,200
15,249
15,289
15,338
15,382
15,425
15,478
15,526
15,578
15,616
15,665
15,765
15,809
15,854
15,870
15,923
15,960
16,010
Vessel B
Flow Rate
gpm
NA
NA
NA
NA
NA
NA
78
NA
NA
NA
NA
95
74
NA
NA
NA
NA
NA
NA
NA
NA
NA
96
92
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
62
NA
NA
NA
NA
NA
NA
NA
NA
NA
88
84
NA
NA
NA
NA
NA
82
NA
NA
NA
NA
NA
Vessel B
Service
Totalizer
gal
4,644,690
4,703,289
4,755,705
4,785,766
4,807,442
4,847,659
4,865,409
4,893,021
4,944,965
4,971,585
4,990,503
5,017,808
5,044,147
5,074,043
5,100,619
5,127,319
5,152,109
5,177,736
5,203,764
5,233,731
5,259,243
5,286,536
5,311,932
5,340,316
5,366,361
5,396,063
5,421,417
5,446,356
5,471,373
5,494,310
5,514,713
5,539,446
5,566,197
5,642,154
5,667,047
5,692,419
5,717,853
5,743,537
5,768,379
5,792,618
5,817,482
5,839,531
5,869,381
5,891,781
5,935,705
5,958,833
5,983,698
6,004,074
6,028,582
6,051,052
6,072,703
6,099,276
6,123,298
6,150,054
6,168,942
6,194,237
6,244,816
6,267,203
6,282,890
6,301,808
6,328,679
6,347,436
6,372,691
Cumulative
Bed Volumes
BV
2,399
2,521
2,631
2,694
2,739
2,823
2,860
2,918
3,026
3,082
3,121
3,178
3,233
3,296
3,351
3,407
3,459
3,512
3,567
3,629
3,682
3,739
3,792
3,852
3,906
3,968
4,021
4,073
4,126
4,173
4,216
4,268
4,324
4,427
4,482
4,534
4,587
4,640
4,694
4,746
4,796
4,848
4,894
4,957
5,004
5,095
5,144
5,196
5,238
5,289
5,336
5,381
5,437
5,487
5,543
5,582
5,635
5,741
5,788
5,820
5,860
5,916
5,955
6,008
Combined
Backwash
Totalizer
gal
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
6,249
6,249
6,249
6,249
6,249
6,249
6,249
6,249
6,249
6,430
6,430
6,430
6,447
6,447
6,447
6,447
6,447
6,447
6,447
-------
Table A-l. US EPA Arsenic Demonstration Project at Stewart, MN - Daily System Operation Log Sheet (Continued)
>
Week
No.
41
42
43
44
45
46
47
48
49
50
Day of
Week
Mon
Tue
Wed
Thu
Fri
Sat
Sun
Mon
Tue
Wed
Thu
Fri
Sat
Sun
Mon
Tue
Wed
Thu
Fri
Sat
Sun
Mon
Tue
Wed
Thu
Fri
Sat
Sun
Mon
Tue
Wed
Thu
Fri
Sat
Sun
Mon
Tue
Wed
Thu
Fri
Sat
Sun
Mon
Tue
Thu
Fri
Sat
Sun
Mon
Tue
Wed
Thu
Fri
Sat
Sun
Mon
Wed
Thu
Fri
Sat
Sun
Mon
Tue
Wed
Thu
Fri
Sat
Sun
Date
11/06/0608:00
11/07/0607:30
11/08/0607:00
11/09/0608:00
11/10/0608:00
11/11/0610:30
11/12/0610:30
11/13/0608:00
11/14/0608:30
11/15/0607:30
11/16/0607:45
11/17/0607:30
11/18/0607:45
11/19/0607:45
11/20/0607:30
11/21/0607:30
11/22/0607:30
11/23/0610:30
11/24/0606:00
11/25/0614:00
11/26/0605:00
11/27/0607:30
11/28/0607:00
11/29/0607:30
11/30/0607:30
12/01/0607:15
12/02/0608:30
12/03/0608:15
12/04/0607:30
12/05/0607:30
12/06/0607:30
12/07/0607:30
12/08/0607:30
12/09/0608:00
12/10/0609:00
12/11/0607:30
12/12/0608:30
12/13/0607:30
12/14/0607:30
12/15/0607:30
12/16/0608:45
12/17/0608:30
12/18/0607:30
12/19/0607:45
12/21/0608:00
12/22/0607:00
12/23/0609:00
12/24/0609:00
12/25/0610:15
12/26/0607:45
12/27/0607:30
12/28/0607:00
12/29/0607:30
12/30/0607:00
12/31/0607:45
01/01/07 08:00
01/03/0707:30
01/04/0707:30
01/05/0708:00
01/06/0709:00
01/07/0709:30
01/08/0707:45
01/09/0707:30
01/10/0707:30
01/11/0707:30
01/12/0708:00
01/13/0708:06
01/14/0707:30
Op
Hours
Mrs
2.3
2.8
1.9
5.0
2.3
2.4
2.3
2.4
2.4
2.3
1.7
2.1
3.1
2.3
2.0
1.8
2.4
2.0
1.0
3.2
1.0
2.0
1.5
2.3
3.4
2.3
2.5
1.2
2.5
2.3
2.8
1.3
3.5
2.1
1.9
2.0
2.3
2.3
1.6
3.1
1.9
1.6
1.7
1.1
2.0
1.3
1.4
3.4
2.5
1.2
2.3
2.3
1.1
2.1
2.0
1.1
2.1
1.2
2.6
2.4
2.3
2.7
1.1
2.7
2.3
1.3
1.7
2.3
Well 3
Gallon
Usage
gal
26,500
33,400
22,900
55,900
25,600
26,000
25,800
26,300
26,500
25,100
19,900
23,700
36,300
25,100
23,300
18,600
26,300
23,800
11,500
38,100
11,500
23,800
17,900
26,000
39,400
25,200
27,000
13,500
27,300
25,400
31,400
14,200
39,800
23,900
21,800
19,900
25,800
25,400
18,100
35,600
23,300
19,200
19,300
12,100
23,300
13,900
26,600
25,800
27,400
13,000
26,700
25,000
12,700
24,500
23,300
13,300
24,000
13,600
28,100
26,000
25,400
28,800
14,300
26,600
25,200
11,200
22,000
26,000
Average
Flowrate
gpm
92
99
01
86
86
81
87
83
84
82
95
88
95
82
94
72
83
98
92
98
92
98
99
88
93
83
80
87
82
84
87
82
90
90
91
66
87
84
89
91
04
00
89
83
94
78
17
26
83
81
93
81
92
94
94
02
90
89
80
81
84
78
17
64
83
44
16
88
Op
Hours
Mrs
2.4
2.3
2.5
2.1
2.2
3.4
2.2
1.8
2.7
1.1
2.1
2.0
1.0
2.2
2.1
1.9
1.1
4.1
2.1
2.2
1.3
2.6
2.3
1.7
1.2
1.9
2.0
1.9
2.3
1.0
1.0
2.0
1.4
1.8
2.0
2.1
2.1
1.1
2.1
2.4
1.3
2.0
2.8
2.9
2.0
3.2
2.0
1.1
2.2
2.0
1.2
1.9
3.3
1.2
2.4
2.5
1.3
3.0
2.0
1.5
1.8
2.3
2.1
1.9
1.5
4.1
1.8
2.3
Well 4
Gallon
Usage
gal
25,700
24,300
26,000
23,600
25,400
36,700
24,600
21,100
29,900
11,900
23,100
20,000
12,000
23,700
24,000
21,100
11,800
45,100
22,700
24,000
12,800
27,600
24,800
18,200
13,300
21,300
22,200
21,600
24,500
11,500
11,700
21,500
16,400
19,200
23,200
22,300
23,400
12,400
23,200
25,500
13,800
26,200
24,500
31,300
20,900
36,100
22,500
11,700
23,800
22,600
13,500
22,000
36,100
32,700
5,500
26,000
13,700
33,600
22,500
16,200
19,500
25,100
23,200
21,000
16,300
46,300
18,000
24,900
Average
Flowrate
gpm
78
76
73
87
92
80
86
95
85
80
83
67
00
80
90
85
79
83
80
82
64
77
80
78
85
87
85
89
78
92
95
79
95
78
93
77
86
88
84
77
77
18
46
80
74
88
88
77
80
88
88
93
82
54
8
73
76
87
88
80
81
82
84
84
81
88
67
80
AERALATER
Backwash
Yes/No
No
No
Yes
No
No
No
No
No
No
No
No
Yes
No
No
No
No
Yes
No
No
No
No
No
No
Yes
No
No
No
No
No
No
No
Yes
No
No
No
No
No
No
Yes
No
No
No
No
No
Yes
No
No
No
No
No
No
Yes
No
No
No
No
Yes
No
No
No
No
No
No
No
Yes
No
No
No
Vessel A
Flow Rate
gpm
NA
91
NA
NA
NA
NA
NA
NA
NA
NA
79
NA
NA
NA
80
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
80
NA
75
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
85
NA
NA
NA
NA
Vessel A
Service
Totalizer
gal
,340,012
,365,280
,390,768
,424,924
,449,596
,480,200
,504,631
,524,741
,554,910
,572,786
,590,890
,612,353
,631,462
,653,106
,675,241
,697,361
,715,751
,741,457
,759,689
,789,513
,801,400
,826,262
,844,536
,868,432
,886,644
,910,219
,931,555
,951,304
,974,963
,994,294
,015,027
,032,541
,051,448
,074,538
,093,470
,116,957
,140,603
,159,335
,176,913
,200,035
,220,901
,240,063
,264,327
,285,802
,327,734
,346,710
,370,532
,388,756
,413,759
,431,065
,449,779
,473,442
,492,463
,510,508
,534,239
,558,362
,596,685
,614,782
,639,143
,657,387
,681,237
,706,459
,725,499
,745,624
,768,374
,791,514
,809,733
,834,171
Cumulative
Bed
Volumes
BV
1 ,062
1 ,115
1 ,168
1 ,240
1 ,291
1 ,355
1 ,406
1 ,448
1 ,511
1 ,549
1 ,586
1 ,631
1 ,671
1 ,716
1 ,763
1 ,809
1 ,847
1 ,901
1 ,939
1 ,001
1 ,026
1 ,078
1 ,116
1 ,166
1 ,204
1 ,253
1 ,298
1 ,339
1 ,389
1 ,429
1 ,472
1 ,509
1 ,548
1 ,597
1 ,636
1 ,685
1 ,735
1 ,774
1 ,810
1 ,859
1 ,902
17,942
17,993
18,038
18,125
18,165
18,215
18,253
18,305
18,341
18,380
18,430
18,469
18,507
18,557
18,607
18,687
18,725
18,776
18,814
18,864
18,916
18,956
18,998
19,046
19,094
19,132
19,183
Vessel B
Flow Rate
gpm
NA
97
NA
NA
NA
NA
NA
NA
NA
NA
84
NA
NA
NA
85
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
82
NA
78
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
88
NA
NA
NA
NA
Vessel B
Service
Totalizer
gal
6,399,479
6,426,258
6,452,897
6,489,356
6,515,446
6,547,814
6,573,623
6,594,873
6,626,737
6,645,596
6,664,733
6,687,376
6,707,501
6,730,357
6,753,700
6,774,971
6,796,312
6,823,364
6,842,510
6,873,854
6,886,323
6,912,404
6,931,532
6,956,573
6,975,600
7,000,183
7,022,460
7,043,023
7,067,677
7,087,749
7,109,289
7,127,515
7,147,116
7,171,010
7,190,628
7,214,884
7,239,317
7,258,613
7,276,767
7,300,620
7,322,035
7,341,717
7,366,572
7,388,564
7,431,556
7,450,993
7,475,324
7,493,909
7,519,454
7,537,148
7,556,249
7,580,422
7,599,831
7,618,282
7,642,535
7,662,075
7,706,492
7,725,065
7,750,075
7,768,803
7,793,350
7,819,370
7,838,990
7,859,768
7,883,250
7,907,230
7,926,089
7,951,464
Cumulative
BedV umes
B
6 64
6 20
6 76
6 52
6 06
6 74
6 28
6 72
6 39
6 78
6 18
6 65
6 07
6 55
6,804
6,848
6,893
6,949
6,989
7,055
7,081
7,135
7,175
7,228
7,267
7,319
7,365
7,408
7,460
7,502
7,546
7,585
7,626
7,675
7,716
7,767
7,818
7,858
7,896
7,946
7,991
8,032
8,084
8,130
8,220
8,260
8,311
8,350
8,403
8,440
8,480
8,531
8,571
8,610
8,660
8,701
8,794
8,833
8,885
8,924
8,975
9,030
9,071
9,114
9,163
9,213
9,252
9,305
Combined
Backwash
Totalizer
gal
6,447
6,447
6,447
6,447
6,447
6,447
6,447
6,447
6,447
6,447
6,447
6,447
6,447
6,447
6,447
6,447
6,447
6,447
6,447
6,447
6,447
6,447
6,447
6,447
6,447
6,447
6,447
6,447
6,447
6,447
6,447
6,447
6,447
6,447
6,447
6,447
6,447
6,447
6,447
6,447
6,447
6,447
6,447
6,447
6,447
6,447
6,447
6,447
6,447
6,447
6,447
6,447
6,447
6,447
6,447
6,447
6,447
6,447
6,447
6,447
6,447
6,447
6,447
6,447
6,447
6,447
6,447
6,447
-------
Table A-l. US EPA Arsenic Demonstration Project at Stewart, MN - Daily System Operation Log Sheet (Continued)
Week
No.
51
52
53
54
55
56
57
Day of
Week
Mon
Tue
Wed
Thu
Fri
Sat
Sun
Mon
Tue
Wed
Thu
Fri
Sat
Sun
Mon
Tue
Wed
Thu
Fri
Sat
Sun
Mon
Tue
Wed
Thu
Fri
Sat
Sun
Mon
Tue
Wed
Thu
Fri
Sat
Sun
Mon
Tue
Wed
Thu
Fri
Sat
Sun
Tue
Wed
Date
01/15/0708:00
01/16/0708:30
01/17/0707:30
01/18/0707:00
01/19/0707:00
01/20/07 07:00
01/21/0708:00
01/22/07 08:00
01/23/07 07:30
01/24/07 07:30
01/25/07 07:30
01/26/07 07:30
01/27/07 08:00
01/28/07 08:00
01/29/07 08:00
01/30/07 07:30
01/31/07 07:30
02/01/0707:10
02/02/07 07:30
02/03/07 08:00
02/04/07 09:00
02/05/07 07:30
02/06/07 10:00
02/07/07 08:00
02/08/07 07:30
02/09/07 07:30
02/10/0707:30
02/11/0707:30
02/12/0700:00
02/13/0700:00
02/14/0700:00
02/15/0700:00
02/16/0700:00
02/17/0700:00
02/18/0700:00
02/19/0700:00
02/20/07 00:00
02/21/0700:00
02/22/07 00:00
02/23/07 00:00
02/24/07 00:00
02/25/07 00:00
02/27/07 07:00
02/28/07 07:00
Well 3
Op
Hours
Mrs
2.1
2.0
2.0
2.8
3.8
2.3
2.4
2.4
2.6
1.6
2.2
2.5
2.4
2.9
2.2
2.3
2.3
1.6
1.9
1.9
1.9
2.1
1.6
2.4
2.0
1.7
2.7
1.7
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
1.8
Gallon
Usage
gal
25,200
23,200
23,100
34,000
43,700
25,500
25,600
26,600
28,100
18,100
24,000
26,700
26,900
31,000
25,100
25,400
24,500
18,000
21,900
22,700
14,100
33,100
19,600
27,500
23,500
18,500
30,500
19,900
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
20,500
Average
Flowrate
gpm
200
193
193
202
192
185
178
185
180
189
182
178
187
178
190
184
178
187
192
199
124
263
204
191
196
181
188
195
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
190
Well 4
Op
Hours
Mrs
2.7
3.3
2.1
1.9
1.5
2.1
2.5
2.2
2.1
2.0
2.0
2.9
2.0
1.6
1.8
2.2
2.5
1.8
3.4
2.3
2.4
2.2
2.6
2.3
2.4
3.2
1.6
2.1
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
2.0
Gallon
Usage
gal
27,400
25,200
31,300
19,800
16,200
23,400
27,800
24,500
23,300
22,700
22,000
33,300
23,100
12,500
24,500
25,000
26,500
21,800
36,700
24,200
25,600
24,300
26,900
25,000
25,000
35,900
17,900
24,400
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
21,200
Average
Flowrate
gpm
169
127
248
174
180
186
185
186
185
189
183
191
193
130
227
189
177
202
180
175
178
184
172
181
174
187
186
194
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
177
AERALATER
Backwash
Yes/No
No
No
Yes
No
No
No
No
No
No
No
Yes
No
No
No
No
No
No
Yes
No
No
No
No
No
No
Yes
No
No
No
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
No
Yes
Vessel A
Flow Rate
gpm
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
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
Vessel A
Service
Totalizer
gal
7,856,720
7,882,406
7,905,111
7,923,716
7,951,674
7,975,078
8,000,617
8,025,044
8,048,103
8,066,929
8,090,760
8,113,365
8,137,246
8,159,132
8,182,649
8,206,499
8,227,971
8,248,826
8,272,385
8,293,484
8,317,470
8,338,083
8,363,100
8,387,479
8,411,013
8,430,179
8,454,253
8,473,187
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
8,809,984
8,830,297
Cumulative
Bed
Volumes
BV
19,230
19,284
19,331
19,370
19,429
19,477
19,531
19,582
19,630
19,669
19,719
19,766
19,816
19,862
19,911
19,961
20,006
20,049
20,098
20,143
20,193
20,236
20,288
20,339
20,388
20,428
20,478
20,518
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
21,221
21,264
Vessel B
Flow Rate
gpm
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
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
Vessel B
Service
Totalizer
gal
7,974,918
8,001,600
8,026,114
8,045,976
8,075,798
8,100,718
8,127,937
8,153,942
8,178,516
8,198,537
8,223,881
8,247,962
8,273,380
8,296,642
8,321,656
8,347,013
8,369,902
8,392,027
8,417,008
8,439,166
8,464,709
8,485,921
8,512,083
8,537,627
8,562,223
8,582,259
8,607,397
8,627,153
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
8,976,131
8,996,994
Cumulative
Bed Volumes
BV
19,354
19,410
19,461
19,503
19,565
19,617
19,674
19,728
19,780
19,822
19,874
19,925
19,978
20,026
20,079
20,132
20,179
20,226
20,278
20,324
20,377
20,422
20,476
20,530
20,581
20,623
20,675
20,717
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
21,446
21,489
Combined
Backwash
Totalizer
gal
6,447
6,447
6,447
6,447
6,447
6,447
6,447
12,141
12,141
12,141
12,141
12,141
12,141
12,141
12,141
12,141
12,141
12,141
12,141
12,141
12,141
12,141
12,141
12,141
12,141
12,141
12,141
12,141
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
12,141
12,141
>
Highlighted columns indicate calculated values.
NA = data not available.
-------
APPENDIX B
ANALYTICAL DATA TABLES
-------
Table B-l. Analytical Results from Long-Term Sampling at Stewart, MN (Continued)
Table B-l. Analytical Results from Long-Term Sampling at Stewart, MN
Sampling Date
Sampling Location
Parameter Unit
Bed Volume (103)
Alkalinity (as CaCOg)
Ammonia (as N)
-luoride
Sulfate
titrate (as N)
Total P (as P)
Silica (as SiO2)
Turbidity
roc
>H
Temperature
DO
ORP
Total Hardness (as CaCO3)
Ca Hardness (as CaCOg)
Mg Hardness (as CaCOg)
As (total)
As (soluble)
As (particulate)
As (III)
As(V)
Fe (total)
:e (soluble)
Mn (total)
i/ln (soluble)
BV
mg/L
mg/L
mg/L
mg/L
mg/L
ug/L
mg/L
NTU
mg/L
S.U.
°C
mg/L
mV
mg/L
mg/L
mg/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
02/02/06'°'
IN
423
1.7
0.3
<1
<0.05
317
27.6
7.3
6.7
8.2
11.4
1.1
-36.6
211
112
98.9
52.3
43.8
8.5
39.8
4.0
1,240
1,159
29.4
29.7
AC
432
1.9
0.3
<1
<0.05
294
25.6
4.3
7.1
8.2
11.8
7.9
250
209
113
95.4
52.4
21.3
31.1
4.2
17.0
1,202
<25
541
118
AF
427
1.7
0.3
<1
<0.05
95.8
24.9
0.9
6.8
8.4
12.4
5.0
203
206
113
93.6
21.2
18.5
2.7
1.3
17.2
<25
<25
127
138
TB
0.7
432
1.7
0.3
<1
<0.05
<10
24.1
2.0
NAW
8.2
10.9
4.8
256
214
113
101
0.3
0.2
<0.1
0.9
<0.1
<25
<25
3.7
3.6
02/14/06
IN
421
-
-
304
25.6
7.9
-
7.6
11.4
1.1
35.2
-
-
36.9
-
-
1,144
21.3
-
AC
442
-
-
275
26.9
15
-
7.9
11.4
NA(b)
128
-
-
33.5
-
1,044
21.0
-
AF
417
-
-
89.3
25.7
1.4
-
7.9
12.4
NA(b)
166
-
-
22.6
-
<25
47.4
-
TA
1.2
438
-
-
<10
24.4
1.7
-
7.9
13.1
NA(b)
175
-
-
0.4
-
<25
10.7
-
TB
1.1
421
-
-
<10
25.4
1.8
-
7.9
13.4
NA(b)
179
-
-
0.3
-
<25
7.2
-
02/21/06
IN
-
-
294
26.3
6.5
-
7.6
12.9
NA(b)
294
-
-
42.7
-
1,238
24.5
-
AC
-
289
25.7
15
-
8.3
10.5
NA(b)
341
-
-
43.8
-
1,205
25.4
-
AF
-
106
25.0
1.1
-
8.3
11.7
NA(b)
333
-
-
27.1
-
<25
47.8
-
TA
1.5
-
<10
25.3
0.8
-
8.2
12.1
NA(b)
323
-
-
0.6
-
<25
14.2
-
TB
1.4
-
<10
24.8
0.9
-
8.4
12.2
NA(b)
321
-
-
0.5
-
<25
11.2
-
02/27/06'°'
IN
1.0
0.4
<1
<0.05
290
26.5
9.2
6.3
7.4
10.6
1.3
271
226
109
117
38.7
35.6
3.2
34.2
1.4
1,193
855
24.3
24.7
AC
1.1
0.4
<1
<0.05
306
24.6
9.6
6.7
7.9
11.5
6.0
273
224
110
114
41.4
32.5
8.9
26.4
6.1
1,192
<25
26.5
24.8
AF
1.1
0.4
<1
<0.05
101
23.0
0.7
6.3
7.7
11.9
4.0
176
212
105
107
24.0
24.4
<0.1
2.0
22.4
<25
<25
40.5
41.3
TA
1.7
1.1
0.4
<1
<0.05
<10
23.8
1.0
NAW
7.8
12.5
3.4
177
210
103
106
0.7
0.4
0.3
1.7
<0.1
<25
<25
17.1
17.5
03/06/06
IN
-
290
24.6
7.1
-
7.7
10.5
1.8
300
-
-
39.7
-
1,202
24.3
-
AC
-
296
24.6
8.9
-
8.3
10.1
6.3
288
-
-
41.8
-
1,185
31.4
-
AF
-
101
24.2
1.5
-
8.0
11.6
3.2
281
-
-
24.8
-
<25
37.2
-
TA
2.2
-
<10
23.7
1.6
-
8.0
11.8
3.6
289
-
-
0.7
-
<25
18.2
-
TB
2.1
-
<10
24.1
3.5
-
8.1
11.4
3.4
307
-
-
0.6
-
<25
20.1
-
(a) TOC sample bottle broke during transit, (b) Operator recorded DO readings as percentage therefore no reading available, (c) TT sample tap is not present. Sample taken from individual vessel for speciation week.
IN = Influent, AC = after gravity filtration; TA = after tank A; TB = after tank B; TT = after combined effluent
NA = not available.
-------
Table B-l. Analytical Results from Long-Term Sampling at Stewart, MN (Continued)
Sampling Date
Sampling Location
Parameter Unit
Bed Volume (103)
Alkalinity (as CaCO3)
Ammonia (as N)
rluoride
Sulfate
Mitrate (as N)
Total P (as P)
Silica (as SiO2)
Turbidity
roc
)H
Temperature
DO
ORP
Total Hardness (as CaCO3)
Ca Hardness (as CaCO3)
Mg Hardness (as CaCO3)
As (total)
As (soluble)
As (particulate)
As (III)
As(V)
Fe (total)
re (soluble)
Mn (total)
\/ln (soluble)
BV
mg/L
mg/L
mg/L
mg/L
mg/L
M9/L
mg/L
NTU
mg/L
S.U.
°C
mg/L
mV
mg/L
mg/L
mg/L
M9/L
M9/L
M9/L
M9/L
M9/L
M9/L
M9/L
M9/L
M9/L
03/14/06
IN
-
422
-
-
-
-
296
23.3
6.1
7.9
12.5
1.1
284
49.3
-
-
-
1,157
-
23.0
AC
-
422
-
-
-
-
281
23.1
8.6
8.2
10.9
6.2
291
48.4
-
-
-
1,168
-
24.1
AF
-
422
-
-
-
-
105
23
0.9
8.1
11.3
3.1
268
30.3
-
-
-
<25
-
33.4
TA
2.6
426
-
-
-
-
<10
23.3
0.8
8.1
10.8
3.9
212
0.6
-
-
-
<25
-
21.2
TB
2.4
426
-
-
-
-
<10
23.5
1.2
8.1
11.8
3.4
188
0.7
-
-
-
<25
-
23.4
03/21/06
IN
-
419
-
-
-
-
313
24.5
11
7.9
16.6
0.8
216
37.2
-
-
-
1,155
-
44.3
AC
-
419
-
-
-
-
315
24.5
9.3
8.3
11.0
5.7
237
38.9
-
-
-
1,139
-
25.0
AF
-
423
-
-
-
-
116
25.1
0.9
8.1
12.6
2.2
249
25.0
-
-
-
<25
-
31.5
TA
2.9
423
-
-
-
-
<10
25.1
0.7
8.2
11.5
2.4
168
0.5
-
-
-
<25
-
23.6
TB
2.7
423
-
-
-
-
<10
25.2
0.6
8.2
11.5
2.7
154
0.5
-
-
-
<25
-
25.8
03/28/06
IN
-
408
1.7
0.4
<1
<0.05
80.9
24.8
5.9
6.2
8.1
12.7
0.6
281
229
117
112
36.5
36.0
0.5
33.4
2.5
1,096
412
19.8
22.8
AC
-
416
1.7
0.4
<1
<0.05
304
25
9.9
6.2
8.3
11.0
5.5
266
213
107
106
41.4
33.3
8.1
24.4
8.9
1,176
<25
23.2
23.2
AF
-
412
1.6
0.4
<1
<0.05
117
-
1
6.2
8.3
11.1
4.9
195
206
102
103
30.2
29.2
1.0
2.9
26.4
<25
<25
28.0
28.8
TA
3.2
416
1.4
0.4
<1
<0.05
<10
24.3
0.6
6.1
8.3
11.1
4.7
158
209
104
105
0.5
0.5
<0.1
0.6
<0.1
<25
<25
25.3
26.0
04/04/06
IN
-
414
-
-
-
-
297
25.1
6.3
8.0
12.2
0.5
8.9
37.1
-
-
-
1,077
-
21.5
AC
-
410
-
-
-
-
290
24.5
8.7
8.4
13.1
5.2
146
37.6
-
-
-
1,059
-
22.9
AF
-
410
-
-
-
-
110
25.5
0.7
8.2
13.6
1.6
148
25.2
-
-
-
<25
-
29.5
TA
3.5
414
-
-
-
-
<10
25.2
0.8
8.2
14.3
2.4
140
0.5
-
-
-
<25
-
26.4
TB
3.3
414
-
-
-
-
<10
25.6
1.1
8.2
15.4
1.9
146
0.5
-
-
-
<25
-
28.3
IN = Influent, AC = after gravity filtration; TA = after tank A; TB = after tank B; TT = after combined effluent
NA = not available.
-------
Table B-l. Analytical Results from Long-Term Sampling at Stewart, MN (Continued)
Sampling Date
Sampling Location
Parameter Unit
Bed Volume (103)
Alkalinity (as CaCO3)
Ammonia (as N)
rluoride
Sulfate
Mitrate (as N)
Total P (as P)
Silica (as SiO2)
Turbidity
roc
3H
Temperature
DO
ORP
Total Hardness (as CaCO3)
Ca Hardness (as CaCO3)
Mg Hardness (as CaCO3)
As (total)
As (soluble)
As (particulate)
As (III)
As(V)
Fe (total)
re (soluble)
Mn (total)
\/ln (soluble)
BV
mg/L
mg/L
mg/L
mg/L
mg/L
M9/L
mg/L
NTU
mg/L
S.U.
°C
mg/L
mV
mg/L
mg/L
mg/L
M9/L
M9/L
M9/L
M9/L
M9/L
M9/L
M9/L
M9/L
M9/L
04/11/06|a)
IN
-
440
-
-
-
-
294
24.1
9.4
7.8
13.0
0.6
21.4
41.8
-
-
-
-
1,175
-
23.1
AC
-
440
-
-
-
-
265
24.4
8.9
8.1
11.5
4.2
210
39.7
-
-
-
-
1,179
-
24.2
AF
-
448
-
-
-
-
94.8
25.1
0.9
8.1
12.9
1.8
186
30.3
-
-
-
-
<25
-
31.9
TA
3.8
440
-
-
-
-
<10
25.1
1.0
8.1
14.0
1.9
168
0.9
-
-
-
-
<25
-
30.5
TB
3.7
435
-
-
-
-
<10
25.2
0.7
8.1
14.1
2.3
118
0.9
-
-
-
-
<25
-
33.2
04/18/06
IN
-
435
448
-
-
-
-
287
289
24.6
24.9
5.0
5.8
8.0
14.2
0.7
89.7
39.0
38.9
-
-
-
-
1,197
1,200
-
23.3
23.6
AC
-
444
435
-
-
-
-
289
291
25.1
25.5
8.8
8.6
8.4
12.7
5.0
213
39.1
39.6
-
-
-
-
1,163
1,156
-
23.8
23.8
AF
-
440
431
-
-
-
-
113
113
23.3
24.3
0.7
0.6
8.2
13.3
2.2
216
22.5
22.5
-
-
-
-
<25
<25
-
28.5
28.2
TA
4.1
444
440
-
-
-
-
11.5
10.9
25.1
24.9
0.5
0.7
8.2
13.8
2.9
164
0.6
0.6
-
-
-
-
<25
<25
-
27.9
28.5
TB
4.0
431
444
-
-
-
-
<10
<10
24.2
24.5
0.4
0.6
8.2
13.3
2.9
160
0.7
0.7
-
-
-
-
<25
<25
-
30.2
30.6
04/25/06
IN
-
423
1.6
0.5
<1
<0.05
296
25.9
4.3
6.2
8.1
12.6
0.6
119
205
111
94.0
39.5
34.1
5.4
27.9
6.2
1,181
931
24.0
24.6
AC
-
415
1.4
0.5
<1
<0.05
289
24.6
7.6
6.2
8.4
12.1
5.1
161
214
118
96.4
43.6
44.9
<0.1
21.7
23.2
1,277
<25
27.7
25.6
AF
-
431
1.3
0.4
<1
0.2
107
25.1
0.5
6.3
8.2
13.8
1.8
229
218
120
99.0
23.1
21.9
1.2
<0.1
21.8
<25
<25
30.4
30.9
TT
4.4
427
1.0
0.4
<1
0.3
<10
24.8
0.6
6.1
8.2
11.7
2.4
152
221
122
99.8
<0.1
<0.1
<0.1
<0.1
<0.1
<25
<25
34.2
35.1
05/02/06
IN
-
421
-
-
-
-
264
25.9
4.6
8.0
10.2
0.5
16.8
36.6
-
-
-
-
1,088
-
22.2
AC
-
420
-
-
-
-
254
25.7
8.3
8.3
10.3
5.0
349
36.1
-
-
-
-
1,063
-
22.6
AF
-
432
-
-
-
-
97.0
25.5
0.6
8.2
10.5
1.9
251
30.8
-
-
-
-
<25
-
29.6
TA
4.8
412
-
-
-
-
<10
26.2
0.4
8.2
10.8
2.5
198
0.7
-
-
-
-
<25
-
28.2
TB
4.7
412
-
-
-
-
<10
26.2
0.8
8.2
10.8
2.1
195
0.9
-
-
-
-
<25
-
32.3
(a) Water quality measurements taken on 04/10/06.
IN = Influent, AC = after gravity filtration; TA = after tank A; TB = after tank B; TT = after combined effluent
NA = not available.
-------
Table B-l. Analytical Results from Long-Term Sampling at Stewart, MN (Continued)
Sampling Date
Sampling Location
Parameter Unit
Bed Volume (103)
Alkalinity (as CaCO3)
Ammonia (as N)
rluoride
Sulfate
Mitrate (as N)
Total P (as P)
Silica (as SiO2)
Turbidity
roc
3H
Temperature
DO
ORP
Total Hardness (as CaCO3)
Ca Hardness (as CaCO3)
Mg Hardness (as CaCO3)
As (total)
As (soluble)
As (particulate)
As (III)
As(V)
Fe (total)
re (soluble)
Mn (total)
\/ln (soluble)
BV
mg/L
mg/L
mg/L
mg/L
mg/L
M9/L
mg/L
NTU
mg/L
S.U.
°C
mg/L
mV
mg/L
mg/L
mg/L
M9/L
M9/L
M9/L
M9/L
M9/L
M9/L
M9/L
M9/L
M9/L
05/09/06|a)
IN
-
410
-
-
-
-
272
25.5
4.1
8.0
11.8
1.5
78.1
35.5
-
-
-
-
1,027
-
21.0
AC
-
419
-
-
-
-
255
26
8.3
8.3
11.0
4.8
140
35.9
-
-
-
-
1,081
-
24.5
AF
-
423
-
-
-
-
90.1
25.9
0.7
8.2
11.0
2.5
170
21.5
-
-
-
-
<25
-
29.7
TA
5.1
423
-
-
-
-
<10
26.3
0.6
8.2
10.6
2.6
168
0.7
-
-
-
-
<25
-
31.2
TB
5.0
410
-
-
-
-
<10
26.3
0.7
8.2
10.5
2.7
165
0.8
-
-
-
-
<25
-
32.9
05/16/06
IN
-
422
-
-
-
-
287
26.3
5.5
8.0
11.0
0.8
-1.4
40.3
-
-
-
-
1,311
-
25.1
AC
-
434
-
-
-
-
282
26.8
8.1
8.2
10.8
5.3
140
40.1
-
-
-
-
1,235
-
25.7
AF
-
426
-
-
-
-
93.3
25.2
0.6
8.9
11.1
2.2
119
21.2
-
-
-
-
<25
-
28.5
TA
5.5
409
-
-
-
-
<10
26
0.4
8.1
10.9
2.0
112
0.5
-
-
-
-
<25
-
30.7
TB
5.3
422
-
-
-
-
<10
26.2
0.7
8.1
11.5
2.2
117
0.7
-
-
-
-
<25
-
32.0
05/24/06
IN
-
414
1.6
0.5
<1
<0.05
289
25.2
4.9
6.3
7.5
12.6
1.1
71.3
200
101
98.8
45.2
41.8
3.3
35.7
6.2
1,057
784
20.3
20.7
AC
-
423
1.6
0.5
<1
<0.05
292
24.5
9.1
6.3
7.8
11.6
5.0
248
189
95.0
93.9
47.2
33.7
13.6
25.5
8.2
1,019
<25
21.8
20.3
AF
-
423
1.5
0.5
<1
0.1
128
24.9
0.7
6.5
7.7
19.3
2.5
386
217
109
108
38.7
26.7
12.0
0.5
26.2
<25
<25
25.1
22.0
TT
5.8
419
1.2
0.5
<1
0.3
<10
25.2
0.7
6.6
7.7
11.7
2.5
150
222
110
111
1.1
1.0
<0.1
0.6
0.3
<25
<25
29.4
28.7
05/30/06
IN
-
424
-
-
-
-
292
24.5
4.3
8.2
10.9
1.9
265
35.7
-
-
-
-
1,063
-
20.3
AC
-
420
-
-
-
-
278
24.4
9.7
8.5
11.5
4.9
340
33.6
-
-
-
-
983
-
20.3
AF
-
420
-
-
-
-
114
24.2
0.6
8.4
11.2
3.8
308
19.8
-
-
-
-
<25
-
21.9
TA
6.2
400
-
-
-
-
25.3
24.5
0.4
8.4
11.4
3.6
300
0.7
-
-
-
-
<25
-
24.6
TB
6.1
367
-
-
-
-
26.7
24.1
1.0
8.4
11.5
3.7
297
0.9
-
-
-
-
<25
-
26.4
(a) Operator turned off potassium permanganate pump after sampling event on 05/09/06.
IN = Influent, AC = after gravity filtration; TA = after tank A; TB = after tank B; TT = after combined effluent
NA = not available.
-------
Table B-l. Analytical Results from Long-Term Sampling at Stewart, MN (Continued)
Sampling Date
Sampling Location
Parameter Unit
Bed Volume (103)
Alkalinity (as CaCO3)
Ammonia (as N)
rluoride
Sulfate
Mitrate (as N)
Total P (as P)
Silica (as SiO2)
Turbidity
roc
PH
Temperature
DO
ORP
Total Hardness (as CaCO3)
Ca Hardness (as CaCO3)
Mg Hardness (as CaCO3)
As (total)
As (soluble)
As (particulate)
As (III)
As(V)
Fe (total)
re (soluble)
Mn (total)
\/ln (soluble)
BV
mg/L
mg/L
mg/L
mg/L
mg/L
M9/L
mg/L
NTU
mg/L
S.U.
°C
mg/L
mV
mg/L
mg/L
mg/L
M9/L
M9/L
M9/L
M9/L
M9/L
M9/L
M9/L
M9/L
M9/L
06/06/06
IN
-
422
-
-
-
-
344
25.7
15.0
8.0
10.9
1.9
316
42.2
-
-
-
-
1,491
-
23.0
AC
-
435
-
-
-
-
264
25.5
9.9
8.2
12.1
3.8
222
37.4
-
-
-
-
1,037
-
21.6
AF
-
431
-
-
-
-
122
25.4
0.7
8.2
11.4
4.2
203
28.6
-
-
-
-
27
-
27.6
TA
6.8
435
-
-
-
-
13.4
26.1
1.2
8.2
11.3
3.1
137
1.1
-
-
-
-
<25
-
27.2
TB
6.6
422
-
-
-
-
18.1
26.1
1.1
8.2
11.2
3.1
139
1.5
-
-
-
-
<25
-
30.6
06/13/06
IN
-
429
-
-
-
-
344
27.0
6.2
8.0
11.4
0.7
337
51.1
-
-
-
-
1,104
-
23.5
AC
-
416
-
-
-
-
338
26.8
8.5
8.3
10.6
5.6
319
50.3
-
-
-
-
1,111
-
24.1
AF
-
433
-
-
-
-
125
26.9
0.6
8.1
11.2
2.1
269
30.4
-
-
-
-
<25
-
26.5
TA
7.2
454
-
-
-
-
<10
27.1
0.5
8.1
11.6
2.5
273
1.1
-
-
-
-
<25
-
28.2
TB
7.0
441
-
-
-
-
14.7
27.0
1.0
8.1
12.6
3.0
259
1.9
-
-
-
-
<25
-
29.2
06/20/06|a|
IN
-
454
1.8
0.6
<1
<0.05
318
28.3
7.6
NA|bl
7.9
11.2
1.1
378
237
119
117
50.9
44.6
6.3
40.7
3.9
1,351
1,335
25.5
26.1
AC
-
416
1.6
0.5
<1
<0.05
312
26.1
8.5
NA|b)
8.3
11.0
4.3
256
236
118
118
45.5
37.3
8.2
27.3
10.0
1,276
68
25.3
25.2
AF
-
425
1.2
0.6
<1
0.3
123
26.6
0.9
NA|b|
8.3
11.2
2.4
190
235
118
117
29.0
25.8
3.2
1.3
24.5
<25
<25
25.5
24.7
TT
7.5
421
1.2
0.6
<1
0.5
14.9
27.0
0.9
NA|bl
8.1
11.4
2.7
195
240
120
119
1.4
1.2
0.2
0.4
0.9
<25
<25
28.3
27.6
06/27/06
IN
-
421
1.6
-
-
<0.05
289
26.8
4.6
8.0
10.1
0.7
404
40.6
-
-
-
-
1,090
-
23.8
AC
-
417
1.3
-
-
<0.05
288
26.1
8.8
8.3
10.4
4.7
209
39.2
-
-
-
-
1,061
-
24.2
AF
-
417
1.5
-
-
0.1
115
26.2
0.7
8.2
11.0
1.7
154
27.9
-
-
-
-
<25
-
26.5
TA
8.0
417
1.0
-
-
0.2
14.2
26.7
0.6
8.2
11.6
2.7
156
1.7
-
-
-
-
<25
-
29.0
TB
7.8
417
1.1
-
-
0.2
17.3
26.5
0.8
8.2
11.5
2.6
154
1.7
-
-
-
-
<25
-
30.4
(a) Operator no longer taking on-site oxidant measurements, (b) Sample analysis failed laboratory QA/QC check.
IN = Influent, AC = after gravity filtration; TA = after tank A; TB = after tank B; TT = after combined effluent
NA = not available.
-------
Table B-l. Analytical Results from Long-Term Sampling at Stewart, MN (Continued)
Sampling Date
Sampling Location
Parameter Unit
Bed Volume (103)
Alkalinity (as CaCO3)
Ammonia (as N)
rluoride
Sulfate
Mitrate (as N)
Total P (as P)
Silica (as SiO2)
Turbidity
roc
3H
Temperature
DO
ORP
Total Hardness (as CaCO3)
Ca Hardness (as CaCO3)
Mg Hardness (as CaCO3)
As (total)
As (soluble)
As (particulate)
As (III)
As(V)
Fe (total)
re (soluble)
Mn (total)
\/ln (soluble)
BV
mg/L
mg/L
mg/L
mg/L
mg/L
M9/L
mg/L
NTU
mg/L
S.U.
°C
mg/L
mV
mg/L
mg/L
mg/L
M9/L
M9/L
M9/L
M9/L
M9/L
M9/L
M9/L
M9/L
M9/L
07/05/06
IN
-
431
1.2
-
-
<0.05
288
24.9
5.3
8.1
11.0
1.7
311
46.1
-
-
-
-
1,321
-
25.8
AC
-
419
1.2
-
-
<0.05
288
24.4
8.4
8.2
10.8
5.0
170
45.5
-
-
-
-
1,305
-
26.1
AF
-
419
0.9
-
-
0.4
101
25.5
1.1
8.2
11.0
3.8
166
26.5
-
-
-
-
<25
-
26.1
TA
8.6
410
0.7
-
-
0.5
<10
25.2
0.8
8.2
11.1
2.6
140
2.7
-
-
-
-
<25
-
27.7
TB
8.4
406
0.9
-
-
0.6
15.8
24.3
0.6
8.2
11.7
2.9
134
2.1
-
-
-
-
<25
-
27.5
07/11/06
IN
-
427
419
NA
-
-
NA
263
291
25.0
25.3
4.2
5.5
8.0
10.9
1.0
163
36.7
38.7
-
-
-
-
993
1,075
-
20.9
21.9
AC
-
423
419
NA
-
-
NA
284
288
24.6
24.1
8.6
8.6
8.3
11.0
7.2
172
38.2
39.1
-
-
-
-
1,056
1,076
-
21.5
22.5
AF
-
423
419
NA
-
-
NA
107
115
24.6
25.8
0.5
0.5
8.2
11.6
3.2
236
26.2
28.7
-
-
-
-
<25
<25
-
23.1
24.5
TA
9.2
419
423
NA
-
-
NA
22.4
26.2
25.8
25.2
0.5
0.6
8.1
12.1
3.3
229
2.1
2.1
-
-
-
-
<25
<25
-
25.1
25.2
TB
8.9
423
419
NA
-
-
NA
29.3
22.9
25.5
25.4
0.3
0.5
8.1
12.1
3.8
179
2.6
2.1
-
-
-
-
<25
<25
-
26.0
23.0
07/18/06
IN
-
439
1.6
0.5
<1
<0.05
350
25.0
6.9
6.4
8.0
10.8
1.6
343
210
116
94.3
43.4
39.4
4.0
32.3
7.0
1,197
852
23.2
23.4
AC
-
447
1.9
0.5
<1
<0.05
307
24.7
10.0
6.6
8.2
11.5
5.2
288
195
96.6
98.0
43.0
33.9
9.1
25.6
8.3
1,230
<25
24.7
24.3
AF
-
439
1.3
0.5
<1
0.2
124
25.0
1.0
6.5
8.2
11.0
2.7
261
224
113
110
38.4
26.1
12.3
0.6
25.6
<25
<25
23.6
23.5
TT
9.6
416
1.2
0.5
<1
0.4
19.9
24.8
0.4
6.5
8.2
10.8
2.5
264
206
104
102
2.3
3.0
<0.1
0.5
2.5
<25
<25
26.4
26.7
07/25/06
IN
-
421
1.7
-
-
<0.05
344
25.0
8.0
8.0
10.2
0.5
371
56.4
-
-
-
-
1,312
-
23.9
AC
-
421
1.9
-
-
<0.05
344
25.7
12.0
8.3
10.8
5.0
267
56.9
-
-
-
-
1,309
-
25.0
AF
-
425
1.4
-
-
<0.05
126
24.9
1.0
8.2
10.6
1.9
156
32.9
-
-
-
-
<25
-
26.1
TA(b)
10.3
421
0.6
-
-
0.7
246
25.8
2.2
8.2""
11.7|a)
62(=)
137|a)
7.4
-
-
-
-
337
-
26.9
TB(b)
10.1
417
0.4
-
-
1.6
336
25.6
3.2
8.2
11.5
5.7
175
9.2
-
-
-
-
524
-
27.5
(a) Water quality measurements taken at sampling location TT.
(b) 07/25/06 TA and TB samples rerun with similar results for As, Fe, and Mn
IN = Influent, AC = after gravity filtration; TA = after tank A; TB = after tank B; TT = after combined effluent
NA = not available.
-------
Table B-l. Analytical Results from Long-Term Sampling at Stewart, MN (Continued)
Sampling Date
Sampling Location
Parameter Unit
Bed Volume (103)
Alkalinity (as CaCO3)
Ammonia (as N)
rluoride
Sulfate
Mitrate (as N)
Total P (as P)
Silica (as SiO2)
Turbidity
roc
PH
Temperature
DO
ORP
Total Hardness (as CaCO3)
Ca Hardness (as CaCO3)
Mg Hardness (as CaCO3)
As (total)
As (soluble)
As (particulate)
As (III)
As(V)
Fe (total)
re (soluble)
Mn (total)
\/ln (soluble)
BV
mg/L
mg/L
mg/L
mg/L
mg/L
M9/L
mg/L
NTU
mg/L
S.U.
°C
mg/L
mV
mg/L
mg/L
mg/L
M9/L
M9/L
M9/L
M9/L
M9/L
M9/L
M9/L
M9/L
M9/L
08/01/06
IN
-
416
1.9
-
-
<0.05
322
27.8
5.3
8.1
10.7
0.6
111
52.3
-
-
-
-
1,121
-
22.3
AC
-
416
1.6
-
-
<0.05
293
28.2
7.5
8.3
12.0
4.4
95.9
44.1
-
-
-
-
1,070
-
22.9
AF
-
412
1.2
-
-
0.4
99.8
28.1
0.4
8.2
11.9
3.1
108
27.3
-
-
-
-
<25
-
24.9
TA
11.0
407
1.0
-
-
1.7'"
20.7
28.3
0.4
8.2
11.5
2.1
88.7
2.8
-
-
-
-
<25
-
25.2
TB
10.8
412
1.0
-
-
0.3
23.9
28.6
0.3
8.2
11.7
2.2
83.9
3.3
-
-
-
-
<25
-
26.2
08/07/06
IN
-
428
1.9
-
-
<0.05
327
24.2
5.5
8.0
11.4
1.1
56.1
56.0
-
-
-
-
1,277
-
24.3
AC
-
424
1.6
-
-
<0.05
315
23.9
9.0
8.3
11.3
4.0
118
51.1
-
-
-
-
1,224
-
23.8
AF
-
424
1.7
-
-
0.1
110
23.9
0.4
8.2
11.7
1.6
103
36.1
-
-
-
-
<25
-
24.1
TA
11.4
416
1.1
-
-
0.5
12.1
24
0.2
8.2
12.3
1.5
94.5
3.0
-
-
-
-
<25
-
24.8
TB
11.2
416
1.2
-
-
0.3
17.4
24.2
0.2
8.2
12.2
2.0
99.7
3.4
-
-
-
-
<25
-
25.4
08/1 5/06
IN
-
421
1.4
-
-
<0.05
312
24.8
6.7
8.1
11.0
1.4
130
38.0
-
-
-
-
1,196
-
22.3
AC
-
434
1.7
-
-
<0.05
313
24.9
8.7
8.4
10.3
4.4
64.5
38.5
-
-
-
-
1,157
-
22.5
AF
-
442
1.7
-
-
0.2
106
24.8
0.3
8.2
10.9
1.8
59.9
27.9
-
-
-
-
<25
-
24.4
TA
11.8
413
1.0
-
-
0.6
12.5
24.1
0.4
8.2
11.3
2.3
65.8
2.0
-
-
-
-
<25
-
22.9
TB
11.6
417
1.2
-
-
0.5
18.7
24.9
0.3
8.2
11.4
2.1
73.7
2.4
-
-
-
-
<25
-
24.3
08/21/06
IN
-
422
1.8
0.4
<1
<0.05
302
24.4
7.8
6.6
8.1
10.4
0.8
268
226
123
103
54.0
46.2
7.8
44.0
2.2
1,310
1,325
24.5
24.0
AC
-
457
1.8
0.4
<1
<0.05
298
24.9
8.5
6.6
8.3
10.7
4.9
191
224
122
102
53.1
40.5
12.7
30.7
9.7
1,292
<25
24.8
23.9
AF
-
403
1.2
0.4
<1
0.4
126
23.3
8.3
3.8|bl
8.2
11.5
2.1
113
219
118
101
36.1
29.2
6.8
0.7
28.6
<25
<25
23.8
24.2
TT
12.1
424
1.0
0.4
<1
0.5
29.1
24.4
1.2
31(b)
8.2
12.2
2.4
89.6
219
115
105
2.8
2.5
0.4
0.7
1.8
<25
<25
25.9
25.9
(a) 08/01/06 TA sample was rerun with similar result for nitrate.
(b) Low effluent TOC levels. Results confirmed with laboratory.
IN = Influent, AC = after gravity filtration; TA = after tank A; TB = after tank B; TT = after combined effluent
NA = not available.
-------
Table B-l. Analytical Results from Long-Term Sampling at Stewart, MN (Continued)
Sampling Date
Sampling Location
Parameter Unit
Bed Volume (103)
Alkalinity (as CaCO3)
Ammonia (as N)
rluoride
Sulfate
Mitrate (as N)
Total P (as P)
Silica (as SiO2)
Turbidity
roc
3H
Temperature
DO
ORP
Total Hardness (as CaCO3)
Ca Hardness (as CaCO3)
Mg Hardness (as CaCO3)
As (total)
As (soluble)
As (particulate)
As (III)
As(V)
Fe (total)
re (soluble)
Mn (total)
\/ln (soluble)
BV
mg/L
mg/L
mg/L
mg/L
mg/L
M9/L
mg/L
NTU
mg/L
S.U.
°C
mg/L
mV
mg/L
mg/L
mg/L
M9/L
M9/L
M9/L
M9/L
M9/L
M9/L
M9/L
M9/L
M9/L
09/05/06
IN
-
474
1.9
-
-
<0.05
299
23.8
5.8
8.1
11.3
1.6
230
43.0
-
-
-
1,187
-
24.9
AC
-
476
1.8
-
-
<0.05
295
24.0
11.0
8.3
11.3
4.0
123
42.6
-
-
-
1,162
-
24.7
AF
-
456
1.5
-
-
0.2
115
23.6
0.8
8.2
11.3
2.6
77.2
26.4
-
-
-
<25
-
23.8
TA
13.0
474
1.3
-
-
0.4
26.3
24.2
0.6
8.2
11.7
2.3
76.1
2.8
-
-
-
<25
-
25.3
TB
12.9
460
1.3
-
-
0.4
30.2
23.7
0.9
8.2
12.4
2.4
83.7
3.2
-
-
-
<25
-
25.6
09/12/06
IN
-
436
1.8
-
-
<0.05
299
24.3
5.2
7.7
10.1
0.7
337
47.2
-
-
-
1,151
-
22.7
AC
-
438
1.6
-
-
<0.05
288
24.7
9.1
8.4
10.2
5.9
193
46.1
-
-
-
1,091
-
22.2
AF
-
441
1.7
-
-
0.1
107
24.2
0.5
8.2
10.8
2.0
199
27.9
-
-
-
<25
-
23.6
TA
13.3
438
1.2
-
-
0.2
25.1
24.5
0.5
8.2
11.2
1.9
104
3.4
-
-
-
<25
-
24.6
TB
13.2
443
1.3
-
-
0.3
27.1
24.2
0.4
8.2
11.7
1.7
103
3.6
-
-
-
<25
-
25.5
09/19/06
IN
-
434
1.6
0.3
<1
<0.05
285
25.9
6.6
6.7
8.0
12.0
1.3
-8.6
204
101
103
39.7
35.6
4.1
28.4
7.2
1,030
925
19.6
20.3
AC
-
439
1.5
0.3
<1
<0.05
292
25.8
7.1
7.0
8.4
12.8
4.5
78.5
210
104
106
41.0
33.5
7.5
25.0
8.5
1,045
<25
20.3
20.3
AF
-
453
1.3
0.2
<1
0.2
105
27
0.3
7.0
8.2
11.8
2.5
89.3
218
107
111
26.1
26.1
<0.1
1.8
24.4
<25
<25
23.2
23.6
TT
13.7
448
1.1
0.2
<1
0.3
22.3
26.7
0.4
6.6
8.2
11.8
2.2
80
215
106
109
2.9
2.8
<0.1
0.1
2.7
<25
<25
22.9
23.5
09/26/06
IN
-
443
1.6
-
-
<0.05
270
24.4
6.3
7.9
10.8
1.2
126
31.4
-
-
-
1,108
-
21.5
AC
-
440
1.7
-
-
<0.05
264
24.2
7.4
8.1
10.5
4.5
121
29.9
-
-
-
1,080
-
21.8
AF
-
454
1.3
-
-
0.3
102
24.7
0.3
8.2
10.6
1.7
101
20.5
-
-
-
<25
-
24.0
TA
14.1
440
0.9
-
-
0.6
35.1
24.2
0.5
8.2
10.8
1.9
84.1
2.8
-
-
-
<25
-
25.8
TB
14.0
433
0.8
-
-
0.6
42.8
23.9
0.2
8.2
11.0
2.2
92.2
3.4
-
-
-
<25
-
26.1
IN = Influent, AC = after gravity filtration; TA = after tank A; TB = after tank B; TT = after combined effluent
NA = not available.
-------
Table B-l. Analytical Results from Long-Term Sampling at Stewart, MN (Continued)
Sampling Date
Sampling Location
Parameter Unit
Bed Volume (103)
Alkalinity (as CaCO3)
Ammonia (as N)
Fluoride
Sulfate
Nitrate (as N)
Total P (as P)
Silica (as SiO2)
Turbidity
TOC
pH
Temperature
DO
ORP
Total Hardness (as CaCO3)
Ca Hardness (as CaCO3)
Mg Hardness (as CaCO3)
As (total)
As (soluble)
As (particulate)
As (III)
As(V)
Fe (total)
Fe (soluble)
Mn (total)
Win (soluble)
BV
mg/L
mg/L
mg/L
mg/L
mg/L
M9/L
mg/L
NTU
mg/L
S.U.
°C
mg/L
mV
mg/L
mg/L
mg/L
M9/L
M9/L
M9/L
M9/L
M9/L
M9/L
M9/L
M9/L
M9/L
10/03/06
IN
-
438
1.7
-
-
<0.05
322
24.3
4.4
-
8.0
10.8
1.2
303
-
-
-
51.6
-
-
-
-
1,132
-
23.4
-
AC
-
452
1.9
-
-
<0.05
326
25.0
8.9
-
8.4
10.7
4.6
39.7
-
-
-
52.3
-
-
-
-
1,126
-
23.6
-
AF
-
449
1.5
-
-
0.3
124
24.5
0.3
-
8.2
11.0
1.8
36.6
-
-
-
31.0
-
-
-
-
<25
-
23.1
-
TA
14.4
429
1.1
-
-
0.7
43.2
24.6
0.5
-
8.3
11.2
3.0
24.9
-
-
-
3.7
-
-
-
-
<25
-
23.5
-
TB
14.4
445
1.0
-
-
0.6
49.1
24.3
0.6
-
8.3
11.3
2.4
23.5
-
-
-
4.2
-
-
-
-
<25
-
24.3
-
10/10/06
IN
-
466
442
NA(a)
-
-
NA(a)
325
339
25.3
25.9
7.1
6.9
-
7.8
11.0
1.9
300
-
-
-
54.9
54.0
-
-
-
-
1,273
1,262
-
25.7
25.6
-
AC
-
448
450
NA(a)
-
-
NA<"
329
340
24.4
24.7
9.2
9.8
-
8.3
10.5
4.9
258
-
-
-
49.7
50.1
-
-
-
-
1,168
1,120
-
24.5
24.2
-
AF
-
459
448
NA(a)
-
-
NA(a)
117
122
25.3
25.0
0.7
0.9
-
8.2
10.8
1.9
239
-
-
-
29.7
31.2
-
-
-
-
<25
29
-
26.3
26.2
-
TA
14.8
433
442
NA(a)
-
-
NA(a)
34.6
39.7
24.8
25.9
0.4
0.6
-
8.2
11.2
1.9
168
-
-
-
4.4
4.4
-
-
-
-
<25
<25
-
25.6
27.8
-
TB
14.7
452
463
NA(a)
-
-
NA(a)
42.2
43.1
25.2
24.1
0.5
1.0
-
8.2
11.5
1.9
151
-
-
-
4.8
4.8
-
-
-
-
<25
<25
-
26.6
26.9
-
10/17/06
IN
-
455
1.9
0.5
<1
<0.05
347
24.3
7.1
6.7
8.0
11.9
2.0
303
206
88.2
118
53.4
39.3
14.0
27.6
11.7
1,021
478
23.3
23.0
AC
-
457
1.9
0.6
<1
<0.05
341
25.0
11.0
6.7
8.4
12.1
5.5
230
211
94.8
116
52.6
37.8
14.8
27.1
10.8
1,045
<25
23.5
23.2
AF
-
446
1.6
0.5
<1
1.5«"
131
24.4
1.2
6.9
8.2
13.4
3.6
161
211
97.2
114
32.6
29.9
2.7
1.3
28.6
<25
<25
23.7
24.5
TT
15.1
469
23<=>
0.5
<1
1.4*'
52.5
25.1
1.1
6.7
8.3
13.5
4.0
154
205
95.2
110
5.6
4.9
0.6
0.9
4.0
<25
<25
23.8
24.5
10/24/06
IN
-
442
1.5
-
-
<0.05
331
23.1
7.5
-
8.1
12.9
1.5
293
-
-
-
56.2
-
-
-
-
1,110
-
21.9
-
AC
-
470
1.5
-
-
<0.05
321
25.2
9.5
-
8.3
11.6
4.8
312
-
-
-
54.1
-
-
-
-
1,105
-
22.6
-
AF
-
465
1.3
-
-
0.2
123
25.1
0.9
-
8.3
11.6
2.7
273
-
-
-
37.7
-
-
-
-
<25
-
24.8
-
TA
15.5
446
1.1
-
-
0.5
43.7
25.0
1.5
-
8.2
12.2
2.1
265
-
-
-
5.4
-
-
-
-
<25
-
23.9
-
TB
15.4
470
1.1
-
-
0.4
49.4
24.8
1.1
-
8.2
12.6
1.9
142
-
-
-
5.9
-
-
-
-
<25
-
24.6
-
(a) Sample bottles not included in cooler per COC.
(b) Samples showed non-detect (<0.05 mg/L) during first analyses. Rerun values are reported, (c) Not able to rerun sample due to discard.
IN = Influent, AC = after gravity filtration; TA = after tank A; TB = after tank B; TT = after combined effluent
NA = not available.
-------
Table B-l. Analytical Results from Long-Term Sampling at Stewart, MN (Continued)
Sampling Date
Sampling Location
Parameter Unit
Bed Volume (103)
Alkalinity (as CaCO3)
Ammonia (as N)
=luoride
Sulfate
\litrate (as N)
Total P (as P)
Silica (as SiO2)
Turbidity
roc
)H
"emperature
DO
ORP
Total Hardness (as CaCO3)
Ca Hardness (as CaCO3)
Mg Hardness (as CaCO3)
As (total)
As (soluble)
As (particulate)
As (III)
As(V)
Fe (total)
re (soluble)
Mn (total)
\/ln (soluble)
BV
mg/L
mg/L
mg/L
mg/L
mg/L
Mg/L
mg/L
NTU
mg/L
S.U.
°C
mg/L
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
10/31/06
IN
-
463
1.5
-
0.05
349
23.5
6.5
-
8.1
11.2
1.7
350
-
-
-
49.1
-
-
-
1,227
23.0
AC
456
1.5
-
-
<0.05
338
24.3
9.0
-
8.6
10.6
5.1
146
46.2
-
-
-
-
1,189
22.6
AF
460
1.0
-
0.4
131
24.2
1.0
8.2
12.4
2.0
161
28.9
-
-
<25
-
28.1
TA
15.8
469
1.0
0.4
51.8
24.5
1.1
8.3
12.4
3.5
159
-
-
-
4.3
<25
-
24.5
TB
15.8
465
1.0
0.4
61.2
25.1
2.3
-
8.3
12.7
3.1
145
-
-
-
5.0
-
-
<25
25.3
11/07/06
IN
457
1.6
-
-
<0.05
316
23.8
11.0
-
8.0
12.1
0.7
248
52.8
-
-
-
-
1,179
23.7
AC
447
1.5
-
-
0.05
301
24.9
9.3
8.3
12.2
4.5
242
50.3
-
-
1,120
-
22.9
AF
-
462
1.4
0.2
120
24.5
1.1
8.3
13.0
3.1
90.2
37.4
<25
-
25.4
TA
16.1
470
1.2
0.2
49.0
25.3
1.1
8.2
13.6
2.0
86.8
-
-
-
5.0
-
<25
-
25.1
TB
16.1
466
1.2
-
-
0.3
58.9
24.1
1.1
-
8.3
14.3
3.0
96.9
-
-
-
6.1
-
-
-
<25
25.4
11/14/06
IN
445
1.6
-
-
0.05
333
24.8
5.7
-
7.9
13.8
1.3
114
53.5
-
-
-
1,255
23.6
AC
443
1.7
-
0.05
304
24.7
10.0
8.3
13.8
5.0
121
50.4
-
1,162
-
23.0
AF
-
445
1.5
0.2
118
24.8
1.0
8.3
13.9
4.0
109
-
-
-
33.1
<25
-
22.5
TA
16.5
433
1.1
-
0.4
50.4
24.7
1.3
-
8.3
14.1
3.3
90.6
-
-
-
5.6
-
-
<25
22.9
TB
16.5
435
1.2
-
-
0.4
56.7
24.4
1.0
-
8.3
14.6
3.4
73.1
5.8
-
-
-
-
<25
23.4
11/28/06
IN
474
1.6
-
-
0.05
275
24.2
6.7
7.6
11.1
2.0
230
41.6
-
-
1,127
-
21.4
AC
-
474
1.7
0.05
256
24.2
9.0
8.1
13.0
4.7
226
-
-
-
38.5
1,088
-
21.5
AF
-
476
1.2
0.3
99.4
23.8
0.7
-
7.9
13.1
1.9
216
-
-
-
25.7
-
<25
29.8
TA
17.1
442
1.2
-
-
0.4
38.4
24.9
1.2
-
8.0
12.2
1.8
216
-
-
-
4.0
-
-
-
-
<25
23.0
TB
17.2
436
1.1
-
-
0.4
49.2
24.5
1.1
-
8.0
12.3
2.0
193
4.9
-
-
-
<25
24.5
Cd
o
IN = Influent, AC = after gravity filtration; TA = after tank A; TB = after tank B; TT = after combined effluent
NA = not available.
-------
Table B-l. Analytical Results from Long-Term Sampling at Stewart, MN (Continued)
Sampling Date
Sampling Location
Parameter Unit
Bed Volume (103)
Alkalinity (as CaCO3)
Ammonia (as N)
Fluoride
Sulfate
titrate (as N)
Total P (as P)
Silica (as SiO2)
Turbidity
roc
)H
Temperature
DO
ORP
Total Hardness (as CaCO3)
Ca Hardness (as CaCO3)
Mg Hardness (as CaCO3)
As (total)
As (soluble)
As (particulate)
As (III)
As(V)
Fe (total)
:e (soluble)
Mn (total)
\/ln (soluble)
BV
mg/L
mg/L
mg/L
mg/L
mg/L
M9/L
mg/L
NTU
mg/L
S.U.
°C
mg/L
mV
mg/L
mg/L
mg/L
M9/L
M9/L
M9/L
M9/L
M9/L
M9/L
M9/L
M9/L
M9/L
12/05/06
IN
449
NA(a)
1.0
<1
<0.05
340
24.0
5.8
6.4
7.9
10.9
2.0
295
220
108
112
52.9
43.3
9.5
36.8
6.6
1,208
894
23.2
24.3
AC
455
NAM
0.4
<1
<0.05
281
23.6
8.2
6.3
8.2
10.3
5.0
252
214
118
95.3
52.2
38.0
14.3
26.9
11.1
1,209
<25
23.9
23.4
AF
447
NAM
0.5
<1
0.7
107
23.4
0.8
6.3
7.9
11.2
2.7
235
213
121
92.7
33.3
28.9
4.4
0.9
28.0
<25
<25
25.0
26.0
TT
17.5
439
NA(a)
0.8
<1
0.7
48.0
23.7
1.3
6.4
8.0
11.4
2.3
201
215
120
94.9
5.7
5.3
0.4
0.6
4.7
<25
<25
24.2
25.8
12/12/06
IN
457
1.7
-
-
<0.05
252
24.4
6.5
7.9
13.4
0.8
346
-
41.1
-
-
-
1,146
22.4
-
AC
448
1.9
-
-
0.1
247
24.9
9.5
8.2
12.9
5.4
93.4
-
42.1
-
-
-
1,137
22.4
-
AF
442
1.6
-
-
0.2
97.7
24.0
0.3
8.0
13.3
2.4
89.1
-
28.3
-
-
-
<25
23.0
-
TA
17.7
446
1.4
-
-
0.3
54.1
24.2
0.3
8.0
13.7
2.3
78.6
-
5.9
-
-
-
<25
24.4
-
TB
17.8
432
1.3
-
-
0.3
43.9
24.1
0.5
8.0
14.3
2.8
84.8
-
4.9
-
-
-
<25
22.8
-
12/18/06
IN
469
1.6
-
-
<0.05
280
26.1
5.7
7.8
12.6
1.1
215
-
42.6
-
-
-
1,298
23.8
-
AC
461
1.8
-
-
<0.05
270
25.4
10.0
8.2
12.6
4.5
171
-
41.2
-
-
-
1,224
23.2
-
AF
457
1.6
-
-
0.1
91.8
26.0
0.7
8.0
12.9
3.2
133
-
33.5
-
-
-
<25
25.1
-
TA
18.0
455
1.2
-
-
0.4
26.6
24.6
0.6
7.9
13.9
2.1
105
-
4.6
-
-
-
<25
23.8
-
TB
18.1
455
1.2
-
-
0.4
33.3
25.3
1.0
8.0
14.1
2.6
114
-
5.2
-
-
-
<25
24.1
-
01/03/07
IN
485
1.7
0.5
<1
<0.05
306
25.1
7.4
6.3
7.7
12.1
2.2
361
226
122
104
53.5
48.9
4.6
43.7
5.2
1,438
1,202
24.3
24.9
AC
487
1.7
0.4
<1
<0.05
290
25.2
8.1
6.7
8.1
12.1
5.5
360
226
120
106
53.1
40.3
12.8
30.8
9.5
1,298
36
24.2
23.7
AF
463
1.1
0.4
<1
0.5
119
24.8
0.9
6.3
7.9
11.5
3.6
299
213
107
106
32.8
30.8
1.9
0.6
30.2
<25
<25
22.5
23.6
TT
18.7
469
1.0
0.5
<1
0.6
64.0
24.8
0.7
6.5
7.9
12.3
6.8
297
227
118
110
5.8
5.6
0.3
0.3
5.2
<25
<25
24.7
24.2
02/27/07
IN
445
1.8
0.6
<1
<0.05
337
24.6
4.8
6.5
7.6
11.5
1.0
389
238
127
112
48.6
36.4
12.2
34.7
1.6
1,427
829
22.7
22.9
AC
445
1.7
0.5
<1
<0.05
307
24.6
8.3
6.6
7.8
11.5
4.3
186
235
130
105
46.4
34.1
12.3
23.7
10.4
919
<25
23.5
23.4
AF
447
1.7
0.6
<1
0.1
158
24.5
1.0
6.6
7.8
10.9
3.2
169
242
134
108
42.7
37.4
5.3
6.6
30.8
<25
<25
25.4
25.5
TT
21.3
450
1.2
0.6
<1
0.3
111
25.1
0.7
6.7
7.7
12.2
2.4
143
247
137
110
9.8
8.6
1.2
1.1
7.5
<25
<25
25.5
26.3
(a) Operator did not take ammonia samples on 12/05/06.
IN = Influent, AC = after gravity filtration; TA = after tank A; TB = after tank B; TT = after combined effluent
NA = not available.
------- |