EPA/600/R-09/113

October 2009

Arsenic Removal from Drinking Water by Coagulation/Filtration

U.S. EP A Demonstration Project at City of Three Forks, MT

Final Performance Evaluation Report

by

Abraham S.C. Chen

Brian J. Yates

Wendy E. Condit

Lili 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 
ii

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. 
iii

FOREWORD

The U.S. Environmental Protection Agency (EPA) is charged by Congress with protecting the Nation’s 

land, air, and water resources. Under a mandate of national environmental laws, the Agency strives to 

formulate and implement actions leading to a compatible balance between human activities and the ability 

of natural systems to support and nurture life. To meet this mandate, EPA’s research program is 

providing data and technical support for solving environmental problems today and building a science 

knowledge base necessary to manage our ecological resources wisely, understand how pollutants affect 

our health, and prevent or reduce environmental risks in the future.

The National Risk Management Research Laboratory (NRMRL) is the Agency’s center for investigation 

of technological and management approaches for preventing and reducing risks from pollution that 

threaten human health and the environment. The focus of the Laboratory’s research program is on 

methods and their cost-effectiveness for prevention and control of pollution to air, land, water, and 

subsurface resources; protection of water quality in public water systems; remediation of contaminated 

sites, sediments and ground water; prevention and control of indoor air pollution; and restoration of 

ecosystems. NRMRL collaborates with both public and private sector partners to foster technologies that 

reduce the cost of compliance and to anticipate emerging problems. NRMRL’s research provides 

solutions to environmental problems by: developing and promoting technologies that protect and improve 

the environment; advancing scientific and engineering information to support regulatory and policy 

decisions; and providing the technical support and information transfer to ensure implementation of 

environmental regulations and strategies at the national, state, and community levels.

This publication has been produced as part of the Laboratory’s strategic long-term research plan. It is 

published and made available by EPA’s Office of Research and Development to assist the user 

community and to link researchers with their clients.

Sally Gutierrez, Director

National Risk Management Research Laboratory
iv

ABSTRACT

This report documents the activities performed during and the results obtained from the arsenic removal 

treatment technology demonstration project at the City of Three Forks, MT facility. The objectives of the 

project were to evaluate: 1) the effectiveness of Kinetico’s FM-248-AS Arsenic Removal System using 

Macrolite® media in removing arsenic to meet the maximum contaminant level (MCL) of 10 μg/L, 2) the

reliability of the treatment system for use at small water facilities, 3) the required system operation and 

maintenance (O&M) and operator skill levels, and 4) the capital and O&M cost of the technology. The 

project also characterized water in the distribution system and residuals generated by the treatment 

process. The types of data collected included system operation, water quality, process residuals, and 

capital and O&M cost.

After review and approval of the engineering plan by the State, the FM-248-AS treatment system was 

installed and became operational on October 30, 2006. The system consisted of two 63-in × 86-in fiber 

reinforced plastic (FRP) contact tanks and two 48-in × 72-in FRP pressure filtration vessels, both

configured in parallel. Each pressure filtration vessel was loaded with 25 ft3 of Macrolite® media to 

which filtration rates up to 10.0 gpm/ft2

was applied. During the performance evaluation study from 

November 27, 2006, and February 8, 2008, the system operated at an average flowrate of 206 gal/min 

(gpm) for 8.9 hr/day, producing 30,499,000 gal of water. This average flowrate corresponded to an 

average contact time of 6.2 min and an average filtration rate of 8.0 gpm/ft2

. 

Problems encountered during the performance evaluation study included programmable logic controller 

(PLC) settings, arsenic and iron particulate breakthrough, and increased differential pressure across the 

media beds, which led to shorter useful run lengths and more frequent backwashing. The actions taken to 

address these problems are detailed in this report.

Source water from Well 2 had an average pH value of 7.5 and contained 59.8 μg/L to 96.7 μg/L of total 

arsenic, 46.8 to 50.8 mg/L of silica (as SiO2), and 17.1 to 53.7 μg/L of phosphorus (as P). The 

predominant soluble arsenic species was As(V) with an average concentration of 74.5 μg/L. Total iron 

concentrations were below the method reporting limit, therefore, in order to make the planned 

coagulation/filtration process work, an iron addition system was installed to provide iron for soluble 

As(V) removal. The amounts of iron added ranged from 1.1 to 2.5 mg/L (as Fe), compared to the target

dosage of 2.0 mg/L (as Fe). 

After the contact tanks, most soluble As(V) was converted to particulate arsenic, presumably via 

adsorption and coprecipitation. As much as 10.6 μg/L of soluble As(V), however, remained in the 

contact tank effluent. Higher iron dosages appear to have very little effect on additional soluble As(V) 

removal. Silica and phosphorus in the raw water might have competed with arsenic for available 

adsorptive sites, thus rendering the coagulation process less effective. The use of higher iron dosages also 

increased solid loading to the pressure filters, causing premature breakthrough of arsenic-laden particles 

within 2 to 4 hr of filter runs. 

Filter effluent samples taken during the first three weeks of system operation contained 17.3 to 30.6 μg/L

of total arsenic and 236 to 936 μg/L of total iron. Of the total amount of total arsenic measured, 23.5

μg/L, on average, existed as particulate arsenic. All iron existed in the particulate form. These results 

suggest that arsenic-laden particles broke through the pressure filters during the filter runs. To examine 

breakthrough characteristics and methods to improve the filter performance, several special studies, 

including some jar tests, were conducted, which included the use of a higher iron dose, implementation of

a finer Macrolite® media size fraction, and addition of a polymer/coagulant aid. However, only a 
v

blending scheme using water from Wells 5, 6, 8, and 9 was successful in reducing arsenic concentrations 

to below the MCL.

In general, filter backwash was triggered manually three times a week (i.e., Monday, Wednesday, and 

Friday) for the first five months and then automatically 5 times a week by the 8 hr run time setpoint. 

Approximately 1,173,000 gal of wastewater, or 3.8% of the amount of water treated, was generated 

during the study. However, because the useful filter run length (i.e., the maximum filter run length that

consistently yielded <10 μg/L total arsenic and <300 μg/L total iron in the effluent) was much shorter

than the actual filter run lengths observed during the study, the percentage of processed water used for

backwashing would have been much higher than 3.8% had the useful filter run length been implemented 

throughout the study. The backwash wastewater contained between 310 mg/L and 388 mg/L of total 

dissolved solids (TDS) and between 130 mg/L and 328 mg/L of total suspended solids (TSS). On 

average, approximately 0.06 lb of arsenic, 1.6 lb of iron, and 0.006 lb of manganese were discharged 

during each backwash event.

The capital investment for the treatment system was $305,447, consisting of $168,142 for equipment, 

$53,435 for site engineering, and $83,870 for installation, shakedown, and startup. Using the system’s 

rated capacity of 250 gpm (or 360,000 gal/day [gpd]), the capital cost was $1,222/gpm (or $0.85/gpd). 

This calculation does not include the cost of the building to house the treatment system. O&M cost, 

estimated at $0.18/1,000 gal, included only the incremental cost for chemicals, electricity, and labor.
vi

CONTENTS

DISCLAIMER..............................................................................................................................................ii

FOREWORD...............................................................................................................................................iii

ABSTRACT................................................................................................................................................. iv

APPENDICES ............................................................................................................................................vii

FIGURES....................................................................................................................................................vii

TABLES ....................................................................................................................................................viii

ABBREVIATIONS AND ACRONYMS ....................................................................................................ix

ACKNOWLEDGMENTS ..........................................................................................................................xii

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 ....................................................................... 8

3.3.1 Source Water........................................................................................................... 11

3.3.2 Treatment Plant Water ............................................................................................ 11

3.3.3 Backwash Wastewater ............................................................................................ 11

3.3.4 Distribution System Water...................................................................................... 11

3.3.5 Residual Solids........................................................................................................ 11

3.4 Special Studies..................................................................................................................... 12

3.5 Sampling Logistics............................................................................................................... 13

3.5.1 Preparation of Arsenic Speciation Kits................................................................... 13

3.5.2 Preparation of Sampling Coolers............................................................................ 13

3.5.3 Sample Shipping and Handling............................................................................... 14

3.6 Analytical Procedures .......................................................................................................... 14

4.0: RESULTS AND DISCUSSION......................................................................................................... 15

4.1 Site Description.................................................................................................................... 15

4.1.1 Pre-existing Facility ................................................................................................ 15

4.1.2 Source Water Quality.............................................................................................. 16

4.1.3 Distribution System................................................................................................. 18

4.2 Treatment Process Description ............................................................................................ 19

4.3 Treatment System Installation.............................................................................................. 25

4.3.1 System Permitting................................................................................................... 25

4.3.2 Building Construction ............................................................................................. 26

4.3.3 System Installation, Startup, and Shakedown ......................................................... 26

4.4 System Operation................................................................................................................. 27

4.4.1 Service Operation.................................................................................................... 27

4.4.2 Chlorine and Iron Additions.................................................................................... 32

4.4.3 Backwash Operation ............................................................................................... 33

4.4.3.1 PLC Settings. .......................................................................................... 35

4.4.3.2 Backwash Flowrates............................................................................... 35

4.4.4 Residual Management............................................................................................. 35
vii

4.4.5 Reliability and Simplicity of Operation .................................................................. 36

4.4.5.1 Pre- and Post-Treatment Requirements.................................................. 36

4.4.5.2 System Automation ................................................................................ 36

4.4.5.3 Operator Skill Requirements .................................................................. 36

4.4.5.4 Preventative Maintenance Activities...................................................... 36

4.4.5.5 Chemical Handling and Inventory Requirements................................... 36

4.5 System Performance............................................................................................................. 37

4.5.1 Treatment Plant Sampling....................................................................................... 37

4.5.1.1 Arsenic and Iron ..................................................................................... 37

4.5.1.2 Manganese .............................................................................................. 43

4.5.1.3 Chlorine Residual ................................................................................... 43

4.5.1.4 Other Water Quality Parameters............................................................. 43

4.5.2 Special Studies........................................................................................................ 43

4.5.2.1 Effect of Δp and Filter Run Time ........................................................... 43

4.5.2.2 Effect of Higher Iron Dosage.................................................................. 44

4.5.2.3 Effect of Media Size Fraction................................................................. 45

4.5.2.4 Effect of Polymers/Coagulants Aids....................................................... 46

4.5.3 Backwash Wastewater Sampling ............................................................................ 49

4.5.4 Distribution System Water Sampling...................................................................... 51

4.6 System Cost.......................................................................................................................... 51

4.6.1 Capital Cost............................................................................................................. 53

4.6.2 O&M Cost............................................................................................................... 54

Section 5.0: REFERENCES ...................................................................................................................... 55

APPENDICES

Appendix A: OPERATIONAL DATA

Appendix B: ANALYTICAL DATA TABLES

FIGURES

Figure 3-1. Process Flow Diagram and Sampling Schedule and Locations........................................... 10

Figure 4-1. Pre-existing Well 2 Pump House ......................................................................................... 15

Figure 4-2. Interior Piping of Well 2 Pump House................................................................................. 16

Figure 4-3. One-million Gallon Water Tank by Treatment Building ..................................................... 19

Figure 4-4. Schematic of Kinetico’s Macrolite® Arsenic Removal System ........................................... 20

Figure 4-5. Chemical Feed Systems ....................................................................................................... 22

Figure 4-6. Contact Tanks with Inlet and Exit Piping ............................................................................ 23

Figure 4-7. Filtration Vessels and Valve Rack ....................................................................................... 23

Figure 4-8. HachTM Turbidimeter for Control of Backwash Duration.................................................... 24

Figure 4-9. Backwash Recycle System................................................................................................... 25

Figure 4-10. Treatment System Building.................................................................................................. 26

Figure 4-11. Treatment System Delivery at Three Forks, MT Site .......................................................... 27

Figure 4-12. Relocation of IN Sampling Location and Chemical Inject Points ....................................... 29

Figure 4-13. Differential Pressure vs. Filter Run Time ............................................................................ 31

Figure 4-14. Vessels A and B Service Time between Backwash Cycles ................................................. 32

Figure 4-15. Chlorine and Ferric Chloride Dosages Over Time............................................................... 33

Figure 4-16. Backwash Frequency Histogram.......................................................................................... 34
viii

Figure 4-17. Arsenic Speciation Results................................................................................................... 41

Figure 4-18. Total Arsenic Concentrations across Treatment Train......................................................... 42

Figure 4-19. Total Iron Concentrations across Treatment Train .............................................................. 42

Figure 4-20. Total Arsenic and Iron Levels with Use of a Higher Iron Dosage....................................... 44

Figure 4-21. Total Arsenic Breakthrough from Filters with 40/60 Mesh Media Only and 40/60 

and 70/80 Mesh Amendment ............................................................................................... 46

Figure 4-22. Total Arsenic and Iron Levels with Use of C-05 Blend....................................................... 47

Figure 4-23. Δp vs. Run Time with Use of C-05 Blend ........................................................................... 48

TABLES

Table 1-1. Summary of Arsenic Removal Demonstration Sites.............................................................. 3

Table 3-1. Predemonstration Study Activities and Completion Dates.................................................... 7

Table 3-2. Evaluation Objectives and Supporting Data Collection Activities........................................ 8

Table 3-3. Sampling Schedule and Analyses .......................................................................................... 9

Table 3-4. Coagulant Aids Jar-Tested by Hawkins............................................................................... 13

Table 4-1. Three Forks, MT Well 2 Source Water Data ....................................................................... 17

Table 4-2. Three Forks, MT Historic Water Quality Data .................................................................... 18

Table 4-3. Properties of 40/60 Mesh Macrolite® Media........................................................................ 20

Table 4-4. Design Specifications of Macrolite® System ....................................................................... 21

Table 4-5. System Inspection Punch-List Items.................................................................................... 28

Table 4-6. Treatment System Operational Parameters.......................................................................... 30

Table 4-7. Unscheduled System Downtime .......................................................................................... 30

Table 4-8. Summary of PLC Settings for Backwash Operations.......................................................... 34

Table 4-9. Summary of Arsenic, Iron, and Manganese Analytical Results........................................... 38

Table 4-10. Summary of Other Water Quality Parameter Results.......................................................... 39

Table 4-11. C-05 FeCl3/Polymer Blend Jar Test Results........................................................................ 47

Table 4-12. Jar Test Results with Alum and Various Polymers.............................................................. 49

Table 4-13. Backwash Wastewater Sampling Test Results..................................................................... 50

Table 4-14. Comparison of Soluble Arsenic and Iron Concentrations in Backwash Wastewater .......... 51

Table 4-15. Distribution System Sampling Results................................................................................. 52

Table 4-16. Capital Investment for FM-248-AS Treatment System ....................................................... 53

Table 4-17. O&M Cost for FM-248-AS Treatment System.................................................................... 54
ix

ABBREVIATIONS AND ACRONYMS

∆p differential pressure

μg/L micrograms per liter

μm micrometers

AAL American Analytical Laboratories

AL polyaluminum hydroxychloride

AM adsorptive media

Al Aluminum

As arsenic

ATS Aquatic Treatment Systems

bgs below ground surface

C/F coagulation/filtration

Ca calcium

CaCO3 calcium carbonate

Cd cadmium

Cl chlorine

Cu copper

DO dissolved oxygen

EPA U.S. Environmental Protection Agency

F fluoride

Fe iron

FeCl3 ferric chloride

FRP fiberglass reinforced plastic

FTW filter-to-waste

gpd gallons per day

gph gallons per hour

gpm gallons per minute

HDPE high-density polyethylene

HIX hybrid ion exchanger

hp horsepower

ICP-MS inductively coupled plasma-mass spectrometry

ID identification

IN wellhead sampling location

IX ion exchange

LCR (EPA) Lead and Copper Rule

MCL maximum contaminant level

MDL method detection limit

MEI Magnesium Elektron, Inc.
x

Mg magnesium

Mn manganese

MT DEQ Montana Department of Environmental Quality

mV millivolts

Na sodium

NA not analyzed

NaOCl sodium hypochlorite

ND not detected

Ni nickel

NTU nephelometric turbidity units

O&M operation and maintenance

OIP operator interface panel

OIT Oregon Institute of Technology

ORD Office of Research and Development

ORP oxidation-reduction potential

P phosphorus

P&ID piping and instrumentation diagram

Pb lead

PD polydiallyldimethylammonium chloride

psi pounds per square inch

psig pounds per square inch gauge

PLC programmable logic controller

PO4 phosphate

POU point-of-use

PVC polyvinyl chloride

PY polyquaternary amine

QA/QC quality assurance/quality control

QAPP Quality Assurance Project Plan

RPD relative percent difference

rpm rotations per minute

RO reverse osmosis

SCADA system control and data acquisition

SDWA Safe Drinking Water Act

SiO2 silica

SMCL secondary maximum contaminant level

SO4 sulfate

SOC synthetic organic compounds

STS Severn Trent Services

TA Vessel A sampling location

TB Vessel B sampling location

TCLP toxicity characteristics leaching procedure

TDH total dynamic head

TDS total dissolved solids
xi

TOC total organic carbon

TSS total suspended solids

TT combined Vessel A and Vessel B sampling location

U uranium

UPS uninterruptible power supply

V vanadium

VOC volatile organic compounds

Zn zinc
xii

ACKNOWLEDGMENTS

The authors wish to extend their sincere appreciation to Mr. Randy Johnson of the City of Three Forks, 

MT. Mr. Johnson monitored the treatment system and collected samples from the treatment and 

distribution systems on a regular schedule throughout the study. This performance evaluation would not 

have been possible without his support and dedication.

Ms. Julia Valigore was the Battelle Study Lead from the inception of this demonstration project through 

July 2007. She is currently pursuing a doctoral degree at the University of Canterbury in New Zealand.
1

1.0 INTRODUCTION

1.1 Background

The Safe Drinking Water Act (SDWA) mandates that the 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 (As) at 0.05 mg/L. Amended in 1996, the 

SDWA required that EPA develop an arsenic research strategy and publish a proposal to revise the 

arsenic MCL by January 2000. On January 18, 2001, EPA finalized the arsenic MCL at 0.01 mg/L (EPA, 

2001). In order to clarify the implementation of the original rule, EPA revised the rule text on March 25, 

2003, to express the MCL as 0.010 mg/L (10 μg/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 out of 115 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 one to six proposals. In April 2003, an independent technical panel 

reviewed the proposals and provided its recommendations to EPA on the technologies that it determined 

were acceptable for the demonstration at each site. Because of funding limitations and other technical 

reasons, only 12 of the 17 sites were selected for the demonstration project. Using the information 

provided by the review panel, EPA, in cooperation with the host sites and the drinking water programs of 

the respective states, selected one technical proposal for each site. 

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, and the community water system in the City of Three Forks, MT 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, another technical panel was convened by EPA to 

review the proposals and provide recommendations to EPA with the number of proposals per site ranging 

from none (for two sites) to a maximum of four. The final selection of the treatment technology at the 

sites that received 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. Kinetico’s Macrolite® Arsenic Removal Technology was selected for 

demonstration at the Three Forks facility. 

As of September 2009, 39 of the 40 systems were operational, and the performance evaluation of 33

systems was completed.
2

1.2 Treatment Technologies for Arsenic Removal

The technologies selected for the Round 1 and Round 2 demonstration host sites include 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, and 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, iron 

[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 cost 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 Kinetico system at the City of Three Forks in Montana

from November 27, 2006, to February 8, 2008. The types of data collected include system operation,

water quality (both across the treatment train and in the distribution system), residuals, and capital and 

preliminary O&M cost. 
3

Table 1-1. Summary of Arsenic Removal Demonstration Sites

Demonstration 

Location Site Name Technology (Media) Vendor

Design 

Flowrate 

(gpm)

Source Water Quality

As 

(μg/L)

Fe

(μg/L)

pH

(S.U.)

Northeast/Ohio

Wales, ME Springbrook Mobile Home Park AM (A/I Complex) ATS 14 38(a) <25 8.6

Bow, NH White Rock Water Company AM (G2) ADI 70(b) 39 <25 7.7

Goffstown, NH Orchard Highlands Subdivision AM (E33) AdEdge 10 33 <25 6.9

Rollinsford, NH Rollinsford Water and Sewer District AM (E33) AdEdge 100 36(a) 46 8.2

Dummerston, VT Charette Mobile Home Park AM (A/I Complex) ATS 22 30 <25 7.9

Felton, DE Town of Felton C/F (Macrolite) Kinetico 375 30(a) 48 8.2

Stevensville, MD Queen Anne’s County AM (E33) STS 300 19(a) 270(c) 7.3

Houghton, NY(d) Town of Caneadea C/F (Macrolite) Kinetico 550 27(a) 1,806(c) 7.6

Newark, OH Buckeye Lake Head Start Building AM (ARM 200) Kinetico 10 15(a) 1,312(c) 7.6

Springfield, OH Chateau Estates Mobile Home Park AM (E33) AdEdge 250(e) 25(a) 1,615(c) 7.3

Great Lakes/Interior Plains

Brown City, MI City of Brown City AM (E33) STS 640 14(a) 127(c) 7.3

Pentwater, MI Village of Pentwater C/F (Macrolite) Kinetico 400 13(a) 466(c) 6.9

Sandusky, MI City of Sandusky C/F (Aeralater) Siemens 340(e) 16(a) 1,387(c) 6.9

Delavan, WI Vintage on the Ponds C/F (Macrolite) Kinetico 40 20(a) 1,499(c) 7.5

Greenville, WI Town of Greenville C/F (Macrolite) Kinetico 375 17 7827(c) 7.3

Climax, MN City of Climax C/F (Macrolite) Kinetico 140 39(a) 546(c) 7.4

Sabin, MN City of Sabin C/F (Macrolite) Kinetico 250 34 1,470(c) 7.3

Sauk Centre, MN Big Sauk Lake Mobile Home Park C/F (Macrolite) Kinetico 20 25(a) 3,078(c) 7.1

Stewart, MN City of Stewart C/F&AM (E33) AdEdge 250 42(a) 1,344(c) 7.7

Lidgerwood, ND City of Lidgerwood Process Modification Kinetico 250 146(a) 1,325(c) 7.2

Midwest/Southwest

Arnaudville, LA United Water Systems C/F (Macrolite) Kinetico 770(e) 35(a) 2,068(c) 7.0

Alvin, TX Oak Manor Municipal Utility District AM (E33) STS 150 19(a) 95 7.8

Bruni, TX

Webb Consolidated Independent School 

District AM (E33) AdEdge 40 56(a) <25 8.0

Wellman, TX City of Wellman AM (E33) AdEdge 100 45 <25 7.7

Anthony, NM

Desert Sands Mutual Domestic Water 

Consumers Association AM (E33) STS 320 23(a) 39 7.7

Nambe Pueblo, NM Nambe Pueblo Tribe AM (E33) AdEdge 145 33 <25 8.5

Taos, NM Town of Taos AM (E33) STS 450 14 59 9.5

Rimrock, AZ Arizona Water Company AM (E33) AdEdge 90(b) 50 170 7.2

Tohono O'odham 

Nation, AZ Tohono O’odham Utility Authority AM (E33) AdEdge 50 32 <25 8.2

Valley Vista, AZ Arizona Water Company AM (AAFS50/ARM 200) Kinetico 37 41 <25 7.8
4

Table 1-1. Summary of Arsenic Removal Demonstration Sites (Continued)

Demonstration 

Location Site Name Technology (Media) Vendor

Design 

Flowrate 

(gpm)

Source Water Quality

As 

(μg/L)

Fe

(μg/L)

pH

(S.U.)

Far West

Three Forks, MT City of Three Forks C/F (Macrolite) Kinetico 250 64 <25 7.5

Fruitland, ID City of Fruitland IX (A300E) Kinetico 250 44 <25 7.4

Homedale, ID Sunset Ranch Development POU RO(f) Kinetico 75 gpd 52 134 7.5

Okanogan, WA City of Okanogan C/F (Electromedia-I) Filtronics 750 18 69(c) 8.0

Klamath Falls, OR Oregon Institute of Technology

POE AM (Adsorbsia/ARM 200/ArsenXnp) 

and POU AM (ARM 200)(g) Kinetico 60/60/30 33 <25 7.9

Vale, OR City of Vale IX (Arsenex II) Kinetico 525 17 <25 7.5

Reno, NV

South Truckee Meadows General 

Improvement District AM (GFH/Kemiron) Siemens 350 39 <25 7.4

Susanville, CA Richmond School District AM (A/I Complex) ATS 12 37(a) 125 7.5

Lake Isabella, CA Upper Bodfish Well CH2-A AM (HIX) VEETech 50 35 125 7.5

Tehachapi, CA

Golden Hills Community Service 

District AM (Isolux) MEI 150 15 <25 6.9

AM = adsorptive media process; C/F = coagulation/filtration; HIX = 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 Arnaudville, LA from 385 to 770 gpm. 

(f) Including nine residential units.

(g) Including eight under-the-sink units.
5

2.0 SUMMARY AND CONCLUSIONS

Based on the information collected from November 27, 2006, to February 8, 2008, the following 

summary and conclusions are provided relating to the overall objectives of the treatment technology 

demonstration study. 

Performance of the arsenic removal technology for use on small systems:

• Operating at 8 gpm/ft2

, Kinetico’s FM-248-AS Arsenic Removal System with Macrolite®

media can remove arsenic to below its MCL of 10 μg/L. However, above MCL levels of 

arsenic, present in both soluble and particulate forms, can break through the filters within 2 hr

of service time, rendering the filtration process ineffective.

• The use of ferric chloride (FeCl3) coagulant can reduce levels of soluble arsenic, present 

predominantly as As(V), after the contact tanks. However, close to or above MCL levels of 

soluble arsenic remain untreated in the contact tank effluent. Increasing the iron dosage to as 

much as 2.5 mg/L (at 31:1 Fe:As ratio) does not appear to be effective in improving the 

treatment results. The poor treatment results might have been caused by the presence of 

silica (at 48.5 mg/L [as SiO2]) and phosphorus, which competed with As(V) for available 

adsorptive sites on iron solids.

• Increasing iron dosage also increases solids loading to the pressure filters, causing premature 

breakthrough of arsenic-laden iron solids from the pressure filters. The use of an organic

polymer, C-05 FeCl3/polymer blend, does not appear to be effective in improving the filter 

performance. The use of C-05 caused clogging to the filters, as evidenced by an increase in 

differential pressure (Δp) buildup rate (i.e., 1.4 to 1.6 psi/hr versus 1.0 psi/hr with the use of 

FeCl3 alone) and several backwash alarms (resulting from the inability to achieve a preset

turbidity threshold within the maximum backwash time).

• The use of a smaller media size fraction (70/80 mesh vs. 40/60 mesh) does not appear to be 

effective in improving the filter’s ability to remove arsenic-laden iron particles.

• Blending with water from other available wells is capable of reducing arsenic concentrations 

to below MCL levels.

Required system O&M and operator skill levels:

• The daily demand on the operator was short, averaging 30 min for routine O&M.

• A significant amount of time and effort was required to adjust and monitor the chemical feed 

system for coagulation/filtration. 

Characteristics of residuals produced by the technology:

• Approximately 3,700 gal of wastewater were produced during each backwash event for both 

vessels. The wastewater contained 0.06 lb of arsenic, 1.6 lb of iron, and 0.006 lb of 

manganese, most of which existed in the particulate form as part of the 4.6 lb of solids 

discharged to the sewer.

• Soluble arsenic and iron concentrations in the backwash wastewater were high (i.e., 10.5 to 

50.4 μg/L for arsenic and 120 to 846 μg/L for iron) when compared with those measured at 

the rest of the arsenic demonstration sites. The soluble metals measured may include 

dispersed colloidal particles due to the presence of elevated silica in water.
6

Capital and O&M cost of the technology:

• The capital investment for the system was $305,447, consisting of $168,142 for equipment, 

$53,435 for site engineering, and $83,870 for installation, shakedown, and startup. 

• The unit capital cost was $1,222/gpm (or $0.85/gpd) based on a 250-gpm design capacity. 

This calculation does not reflect the building cost as it was funded by the City.

• The O&M cost was $0.18/1,000 gal including incremental cost for chemicals, electricity, and 

labor. 
7

3.0 MATERIALS AND METHODS

3.1 General Project Approach

Following the predemonstration activities summarized in Table 3-1, the performance evaluation study of 

the Kinetico treatment system began on November 27, 2006, and operational data collection ended on 

February 8, 2008. Table 3-2 summarizes the types of data collected and considered as part of the

technology evaluation process. The overall system performance was based on its ability to consistently 

remove arsenic to below the target MCL of 10 μg/L through the collection of water samples across the 

treatment train, as described in the Study Plan (Battelle, 2006). The reliability of the system was 

evaluated by tracking the unscheduled system downtime and frequency and extent of repair and 

replacement. The unscheduled downtime and repair information were recorded by the plant operator on a 

Repair and Maintenance Log Sheet. 

The O&M and operator skill requirements were assessed through quantitative data analysis and 

qualitative observational considerations, including the need for pre- and/or post-treatment, level of system 

automation, extent of preventative maintenance activities, frequency of chemical handling and inventory,

and general knowledge needed for relevant chemical processes and related health and safety practices. 

The staffing requirements for the system operation were recorded on an Operator Labor Hour Log Sheet. 

The quantity of aqueous and solid residuals generated was estimated by tracking the volume of backwash 

water produced during each backwash cycle. Backwash wastewater was sampled and analyzed for 

chemical characteristics. 

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 equipment, engineering, and installation, as well as the O&M cost for media replacement and 

disposal, chemical supply, electricity usage, and labor. 

Table 3-1. Predemonstration Study Activities and Completion Dates

Activity Date

Introductory Meeting Held November 30, 2004

Project Planning Meeting Held April 5, 2005

Draft Letter of Understanding Issued April 12, 2005

Final Letter of Understanding Issued April 22, 2005

Request for Quotation Issued to Vendor April 22, 2005

Vendor Quotation Received May 19, 2005

Purchase Order Established June 8, 2005

Letter Report Issued June 15, 2005

Engineering Package Submitted to MT DEQ November 2, 2005

Study Plan Issued September 14, 2005

System Permit Granted by MT DEQ January 26, 2006

Building Construction Permit Granted by MT DEQ April 7, 2006

Building Construction Began April 13, 2006

FM-248-AS System Shipped/Delivered May 24/30, 2006

System Installation Completed June 5, 2006

Building Completed July 31, 2006

System Shakedown Completed October 30, 2006

Performance Evaluation Began November 27, 2006

MT DEQ = Montana Department of Environmental Quality
8

Table 3-2. Evaluation Objectives and Supporting Data Collection Activities

Evaluation Objective Data Collection

Performance -Ability to consistently meet 10 μg/L of arsenic in treated water

Reliability -Unscheduled system downtime

-Frequency and extent of repairs including a description of problems, materials

and supplies needed, and associated labor and cost

System O&M and Operator 

Skill Requirements

-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

Residual Management -Quantity and characteristics of aqueous and solid residuals generated by 

system operation

System Cost -Capital cost for equipment, engineering, and installation

-O&M cost for chemical usage, electricity consumption, 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 according to 

instructions provided by the vendor and Battelle. As long as possible, the plant operator recorded daily 

system operational data, such as pressure, flowrate, totalizer, and hour meter readings on a Daily System 

Operation Log Sheet, checked the sodium hypochlorite (NaOCl) and FeCl3 levels, 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 should be contacted for troubleshooting. The plant 

operator recorded all relevant information, including the problem encountered, course of actions taken, 

materials and supplies used, and associated cost and labor incurred, on the Repair and Maintenance Log 

Sheet. On a weekly basis, the plant operator measured several water quality parameters onsite, including 

temperature, pH, dissolved oxygen (DO), oxidation-reduction potential (ORP), and residual chlorine, and 

recorded them on a Weekly Onsite Water Quality Parameters Log Sheet. Monthly backwash data also 

were recorded on a Backwash Log Sheet.

The capital cost for the arsenic removal system consisted of the cost for equipment, site engineering, and 

system installation. The O&M cost consisted of the cost for chemical usage, electricity consumption, and 

labor. Consumption of NaOCl and FeCl3 was tracked on the Daily System Operation Log Sheet. 

Electricity consumption was determined from utility bills. Labor for various activities, such as routine 

system O&M, troubleshooting and repairs, and demonstration-related work, was tracked using an 

Operator Labor Hour Log Sheet. The routine system O&M included activities such as completing field 

logs, replenishing chemical solutions, ordering supplies, performing system inspections, and others as 

recommended by the vendor. Labor hours 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, were recorded, but not used for the cost analysis.

3.3 Sample Collection Procedures and Schedules

To evaluate system performance, samples were collected at the wellhead, across the treatment plant, 

during Macrolite® filter backwash, and from the distribution system. Table 3-3 provides the sampling 

schedule and analytes measured during each sampling event. Figure 3-1 presents a flow diagram of the
9

Table 3-3. Sampling Schedule and Analyses

Sample 

Type

Sample 

Locations

(a)

No. of 

Samples Frequency Analytes

Collection 

Date(s) and 

Results

Source 

Water

IN 1 Once Onsite: pH, 

temperature, DO, and 

ORP

Offsite: As(III), As(V),

As (total and soluble), 

Fe (total and soluble), 

Mn (total and soluble), 

U (total and soluble), 

V (total and soluble), 

Na, Ca, Mg, Cl, F, NO2, 

NO3, NH3, SO4, SiO2, 

PO4, alkalinity, 

turbidity, TDS, and 

TOC 

Table 4-1

Treatment 

Plant Water

IN, AC, 

TA, and TB 

4 Weekly

(nonspeciation 

sampling)

Onsite: pH, 

temperature, DO, ORP, 

and Cl2 (total and free)

Offsite: As (total), 

Fe (total), Mn (total), 

SiO2, P (total), 

alkalinity, and turbidity

Appendix B

IN, AC, and 

TT

3 Monthly

(speciation 

sampling)

Onsite: pH, 

temperature, DO, ORP, 

and Cl2 (total and free)

Offsite: As(III), As(V), 

As (total and soluble), 

Fe (total and soluble), 

Mn (total and soluble), 

Ca, Mg, F, NO3, SO4,

SiO2, P (total), 

alkalinity, and turbidity 

Appendix B

Backwash 

Wastewater

Discharge 

Line

2 Monthly As (total and soluble), 

Fe (total and soluble), 

Mn (total and soluble), 

TDS, TSS, and pH 

Table 4-13

Residual 

Sludge

Discharge 

Area

2–3 Once TCLP metals and

total Al, As, Ca, Cd, 

Cu, Fe, Mg, Mn, Ni, P, 

Pb, Si, and Zn

Not 

Sampled

Distribution 

Water

One 

Residence 

and Two 

NonResidences

3 Monthly As (total), Fe (total), 

Mn (total), Cu, Pb, pH, 

and alkalinity

Table 4-15

(a) IN = at wellhead; AC = after contact tanks; TA = after Vessel A; TB = after Vessel B; 

TT = after filter effluent combined

TCLP = toxicity characteristics leaching procedure; TDS = total dissolved solids; TOC = 

total organic carbon; TSS = total suspended solids
10

FILTER

TANK

A

FILTER

TANK

B

INFLUENT

(WELL 2) Three Forks, MT

Macrolite® Arsenic Removal System

Design Flow: 250 gpm

TCLP metals, Al 

(total), As, Ca, Cd, 

Cu, Fe, Mg, Mn, Ni, 

P, Pb, Si and Zn

SANITARY SEWER

TO LAGOON

DISTRIBUTION 

SYSTEM

Weekly (non-speciation sampling)

Monthly (speciation sampling)

Footnote

(a) On-site analyses

pH, TDS, turbidity,

As (total, soluble),

Fe (total, soluble),

Mn (total, soluble)

TA TB

IN

TT

AC

pH(a)

, temperature(a)

, DO(a)

, ORP(a)

, 

As (total), Fe (total), Mn (total), SiO2, 

P (Total), alkalinity and turbidity

LEGEND

LEGEND

INFLUENT Unit Process

IN At Well Head

BW Backwash Sampling Location

SS Sludge Sampling Location

Process Flow

Backwash Flow

DA: Cl2 Chlorine Disinfection

TT After Filter Effluent Combined

AC After Contact Tanks

TB After Tank B

TA After Tank A

Water Sampling Locations

pH(a)

, temperature(a), DO(a)

, ORP(a)

,

Cl2 (total and free), As speciation, Fe 

(total and soluble), Mn (total and 

soluble), Ca, Mg, F, NO3, SO4, SiO2,

P (total), alkalinity, and turbidity 

BW

CONTACT 

TANKS

pH(a)

, temperature(a)

, DO(a)

, ORP(a)

, 

Cl2 (total and free)(a)

, As (total), Fe 

(total), Mn (total), SiO2, P (total), 

alkalinity and turbidity

DA: FeCl3

BACKWASH

RECYCLE TANK

SS

10%

90%

BAG

FILTER

DA: Cl2

RECYCLE

PUMP

pH(a)

, temperature(a)

, DO(a)

, ORP(a)

,

As speciation, Fe (total and soluble), Mn (total 

and soluble), Ca, Mg, F, NO3, SO4, SiO2, 

P (total), alkalinity, and turbidity 

pH(a)

, temperature(a)

, DO(a)

, ORP(a)

,

Cl2 (total and free), As speciation, Fe 

(total and soluble), Mn (total and 

soluble), Ca, Mg, F, NO3, SO4, SiO2,

P (total), alkalinity, and turbidity 

pH(a)

, temperature(a)

, DO(a)

, ORP(a)

, 

Cl2 (total and free)(a)

, As (total), Fe 

(total), Mn (total), SiO2, P (total), 

alkalinity and turbidity

FILTER

TANK

A

FILTER

TANK

B

INFLUENT

(WELL 2) Three Forks, MT

Macrolite® Arsenic Removal System

Design Flow: 250 gpm

TCLP metals, Al 

(total), As, Ca, Cd, 

Cu, Fe, Mg, Mn, Ni, 

P, Pb, Si and Zn

SANITARY SEWER

TO LAGOON

DISTRIBUTION 

SYSTEM

Weekly (non-speciation sampling)

Monthly (speciation sampling)

Footnote

(a) On-site analyses

pH, TDS, turbidity,

As (total, soluble),

Fe (total, soluble),

Mn (total, soluble)

TA TB

IN

TT

AC

pH(a)

, temperature(a)

, DO(a)

, ORP(a)

, 

As (total), Fe (total), Mn (total), SiO2, 

P (Total), alkalinity and turbidity

LEGEND

LEGEND

INFLUENT Unit Process

IN At Well Head

BW Backwash Sampling Location

SS Sludge Sampling Location

Process Flow

Backwash Flow

DA: Cl2 Chlorine Disinfection

TT After Filter Effluent Combined

AC After Contact Tanks

TB After Tank B

TA After Tank A

Water Sampling Locations

pH(a)

, temperature(a), DO(a)

, ORP(a)

,

Cl2 (total and free), As speciation, Fe 

(total and soluble), Mn (total and 

soluble), Ca, Mg, F, NO3, SO4, SiO2,

P (total), alkalinity, and turbidity 

BW

CONTACT 

TANKS

pH(a)

, temperature(a)

, DO(a)

, ORP(a)

, 

Cl2 (total and free)(a)

, As (total), Fe 

(total), Mn (total), SiO2, P (total), 

alkalinity and turbidity

DA: FeCl3

BACKWASH

RECYCLE TANK

SS

10%

90%

BAG

FILTER

DA: Cl2

RECYCLE

PUMP

pH(a)

, temperature(a)

, DO(a)

, ORP(a)

,

As speciation, Fe (total and soluble), Mn (total 

and soluble), Ca, Mg, F, NO3, SO4, SiO2, 

P (total), alkalinity, and turbidity 

pH(a)

, temperature(a)

, DO(a)

, ORP(a)

,

Cl2 (total and free), As speciation, Fe 

(total and soluble), Mn (total and 

soluble), Ca, Mg, F, NO3, SO4, SiO2,

P (total), alkalinity, and turbidity 

pH(a)

, temperature(a)

, DO(a)

, ORP(a)

, 

Cl2 (total and free)(a)

, As (total), Fe 

(total), Mn (total), SiO2, P (total), 

alkalinity and turbidity

Figure 3-1. Process Flow Diagram and Sampling Schedule and Locations
11

treatment system along with the analytes and schedule for 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). 

The procedure for arsenic speciation is described in Appendix A of the QAPP.

3.3.1 Source Water. During the initial site visit, one set of source water samples was collected 

and speciated using an arsenic speciation kit (Section 3.5.1). The sample tap was flushed for several

minutes before sampling; special care was taken to avoid agitation, which might cause unwanted 

oxidation. Analytes for the source water samples are listed in Table 3-3.

3.3.2 Treatment Plant Water. The initial plan was for the plant operator to collect treatment 

plant water samples weekly, on a four-week cycle, for on- and offsite analyses. For the first week of each 

four-week cycle, samples were collected at the wellhead (IN), after the contact tanks (AC), and after the 

effluent from the two filtration vessels combined (TT), and speciated onsite and analyzed for the analytes 

listed under speciation sampling in Table 3-3. On the second, third, and fourth weeks of the four-week 

cycle, samples were collected at IN, AC, after Vessel A (TA), and after Vessel B (TB) and analyzed for 

the analytes listed under non-speciation sampling in Table 3-3. Sampling following this schedule was 

only conducted in November to December 2006, and March to April 2007. Due to earlier-than-expected 

particulate iron and arsenic breakthrough in the filter effluent, this sampling schedule was discontinued 

and a series of special studies under varying process conditions was conducted as described in 

Section 3.4.

3.3.3 Backwash Wastewater. Five sets of backwash water samples were collected by the plant 

operator from December 2006 to April 2007. Tubing, connected to the tap on the discharge line of each 

vessel, directed a portion of backwash wastewater at about 1 gpm into a clean, 32-gal container over the 

entire backwash duration from each vessel. After the content in the container was thoroughly mixed, 

composite samples were collected and/or filtered onsite with 0.45-μm disc filters. Analytes for the 

backwash samples are listed in Table 3-3.

3.3.4 Distribution System Water. Prior to system startup from June to September 2005, four 

monthly baseline distribution water samples were collected from two non-residences and one residence 

that had been included in the City’s Lead and Copper Rule (LCR) sampling. Among others, the samples 

were analyzed for arsenic, lead, and copper. Following system startup, distribution system water 

sampling continued on a monthly basis at the same three locations from December 2006 to January 2008.

Homeowners collected samples following an instruction sheet developed according to the Lead and 

Copper Monitoring and Reporting Guidance for Public Water Systems (EPA, 2002). The dates and times

of last water usage before sampling and of actual sample collection were recorded for calculation of the 

stagnation time. All samples were collected from a cold-water faucet that had not been used for at least 6 

hr to ensure that stagnant water was sampled.

The distribution system water sampling might not achieve the intended results because the Well 2 treated 

water had been blended with source water from Wells 5, 6, 8, and 9, which contained little or no arsenic. 

Nonetheless, the sampling proceeded as planned. 

3.3.5 Residual Solids. Residual solids produced by the treatment process consisted of only

backwash wastewater solids. Residual solids were not sampled due to the request of the operator to end 

the study after February 8, 2008 prior to sample collection.
12

3.4 Special Studies

A series of special studies was conducted to improve the performance of the pressure filters for iron and 

arsenic removal. The studies were necessary because the analytical results from the first three weeks of 

treatment plant sampling (i.e., from November 29 through December 12, 2006) indicated significantly 

elevated arsenic and iron concentrations in the filter effluent. The studies performed involved:

• Filter run-length with the use of higher iron doses. A filter run length study was 

conducted on December 20, 2006, and then on January 10, 2007. The December 20 

study involved collecting treatment plant water samples from all four sampling 

locations at 1 and 4 hr of service time and analyzing the samples for total arsenic, 

iron, and manganese. The January 10 study encompassed the collection of similar 

water samples at approximately 1.0, 2.0, and 4.0 hr and the analysis of the samples 

for all five onsite analytes (Table 3-3) and total and/or soluble arsenic, iron, and 

manganese. The iron dosages applied during the two studies were 1.8 and 2.2 mg/L 

(as Fe), respectively. Regular sampling as outlined in Table 3-3 was temporarily 

suspended from December 12, 2006, to March 21, 2007.

• Use of a finer filter media size fraction. Because a significant amount of arsenicladen iron particles continued to prematurely break through the pressure filters, the 

top 6-in of the filter media at 40/60 mesh was replaced with a 6-in layer of finer 

media at 70/80 mesh. Upon completion of the media replacement on March 13, 

2007, regular sampling as outlined in Table 3-3 resumed on March 21, 2007, and 

lasted until April 25, 2007. 

• Use of an iron/organic polymer blend. Analytical results collected between March 21 and 

April 25, 2007, revealed that the media bed modification failed to produce the anticipated 

result and that a significant amount of particulate iron and arsenic continued to penetrate 

through the pressure filters. Efforts were then made to determine if the use of a coagulant aid 

might help form more filterable flocs, thereby improving the filter performance. An iron/

polymer mixture (C-05, a blend of 38% FeCl3 with an organic polymer; the amount and type 

of the polymer were unknown) was recommended by Kinetico to replace the FeCl3, so that no 

additional feed equipment would be needed for separate polymer addition. 

To evaluate iron and polymer dosages, 12 jar tests were performed by Kinetico on June 4, 

2007. Source water collected from the IN location was dosed with three free chlorine 

dosages, i.e., 0.5, 1.0, and 1.5 mg/L (as Cl2), and four C-05 dosages, i.e., 1.0, 1.5, 2.0, and 2.5 

mg/L (as Fe). After mixing for 8 min, supernatant in each jar was filtered with 0.45-μm disc 

filters before being analyzed for arsenic and iron. 

The use of C-05 in the full-scale system was started on July 6, 2007 with the chlorine and C05 blend dosages set at 1.5 mg/L (as Cl2) and 2.5 mg/L (as Fe), respectively. (The C-05 

blend was delivered to the injection point by ramping up the feed pump stroke length by 

about 10% to account for the polymer content in the blend.) A run-length study was carried 

out on July 17, 2007, with filter effluent samples collected at approximately 3, 6, and 10 hr 

and analyzed for arsenic and iron. Because of lack of improvement to the filter effluent, the 

use of C-05 blend was discontinued in August 2007.

While awaiting the implementation of C-05 iron/polymer blend, regular sampling as outlined

in Table 3-3 was suspended again from April 25, 2007 to July 17, 2007. Afterwards, regular 

sampling was suspended indefinitely. 
13

• Use of other coagulant aids. On October 30, 2007, eight jar tests were conducted onsite by a 

chemical supplier, Hawkins, to further investigate the use of coagulant aids, including alum 

and seven polymer blends, on coagulation of arsenic and iron particulates. The jar tests were 

performed because the use of the C-05 blend resulted in minimal, if any, improvement to the 

filter effluent. Water, collected from the AC location containing 2.2 mg/L of iron (as Fe),

was dosed with a varying amount of the coagulant aids listed in Table 3-4. After mixing for 

20 min, supernatant from each jar was filtered with 0.45-μm disc filters before being 

analyzed for arsenic and iron. The use of these coagulant aids was never implemented at the 

site because of concerns over media fouling by the facility operator. 

For each run length study, rise of Δp across the pressure filters was carefully monitored, along with 

particulate iron and arsenic concentrations, against incremental filter run times. These studies allowed for 

the evaluation of filter performance between consecutive backwash events. The results of the run length 

studies and associated jar tests are discussed in Section 4.5.2.

During the special study period, the City began to increase the blending ratio between treated water from 

Well 2 and raw water from other wells to meet the 10-μg/L arsenic MCL within the distribution system. 

Table 3-4. Coagulant Aids Jar-Tested by Hawkins

Polymer Description

Unit Cost

($/gal)

Dosage

(mg/L)

Aqua Hawk 427 Polymer blend (AL/PD/PY) $10.6l 1

Aqua Hawk 6527 PD $11.33 1

Aqua Hawk 6547 PD $16.04 1

Alum NA NA 10

Aqua Hawk 9827 Long chain polymer NA 0.2

Aqua Hawk 9827 Long chain polymer NA 0.5

Aqua Hawk 9847 Long chain polymer NA 0.2

Aqua Hawk 9847 Long chain polymer NA 0.5

AL = Polyaluminum hydroxychloride

PD = Polydiallyldimethylammonium chloride

PY = Polyquaternary amine

3.5 Sampling Logistics

3.5.1 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 QAPP (Battelle, 2004).

3.5.2 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 preprinted, colored-coded 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 demonstration site, the sampling date, a two-letter code 

for a specific sampling location, and a one-letter code designating the arsenic speciation bottle (if 
14

necessary). The sampling locations at the treatment plant were color-coded for easy identification. The 

labeled bottles were separated by sampling location, placed in Zip-lock® bags, and packed into the cooler. 

In addition, all sampling- and shipping-related materials, such as disposable gloves, sampling instructions, 

chain-of-custody forms, prepaid/addressed FedEx air bills, and bubble wrap, were included. The chain-ofcustody forms and air bills were complete except for the operator’s signature and the sample dates and 

times. After preparation, the sample cooler was sent to the site via FedEx for the following week’s 

sampling event. 

3.5.3 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 verified that all samples indicated on the chain-of-custody forms were included and intact. 

Sample IDs were checked against the chain-of-custody forms, and the samples were logged into the 

laboratory sample receipt log. Discrepancies noted by the sample custodian were addressed with the plant 

operator by the Battelle Study Lead. 

Samples for metal analyses were stored at Battelle’s inductively coupled plasma-mass spectrometry (ICPMS) laboratory. Samples for other water quality analyses were packed in separate coolers and picked up 

by couriers from American Analytical Laboratories (AAL) in Columbus, OH; TCCI Laboratories in New 

Lexington, OH; and/or Belmont Labs in Englewood, OH, all of which were under contract with 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. 

3.6 Analytical Procedures

The analytical procedures described in Section 4.0 of the QAPP (Battelle, 2004) were followed by 

Battelle ICP-MS, AAL, TCCI Laboratories, and Belmont Labs. Laboratory quality assurance/quality 

control (QA/QC) of all methods followed the prescribed guidelines. Data quality in terms of precision, 

accuracy, method detection limits (MDLs), and completeness met the criteria established in the QAPP (i.e., 

relative percent difference [RPD] of 20%, percent recovery of 80% to 120%, and completeness of 80%). 

The quality assurance 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 

WTW Multi 340i handheld field meter, which was calibrated for pH and DO prior to use following the 

procedures provided in the user’s manual. The ORP probe also was checked for accuracy by measuring 

the ORP of a standard solution and comparing it to the expected value. The plant operator collected a 

water sample in a clean, plastic beaker and placed the probe in the beaker until a stable value was 

obtained. The plant operator also performed free and total chlorine measurements using Hach chlorine 

test kits following the user’s manual.

 
4.0 RESULTS AND DISCUSSION

4.1 Site Description

4.1.1 Pre-existing Facility. The City of Three Forks had a population of approximately 2,000 

residents. The water system was supplied by five wells (Wells 2, 5, 6, 8, and 9), which had a maximum 

combined capacity of 1,200,000 gpd. Located near the Jefferson River, Wells 5, 6, 8, and 9 did not 

contain elevated levels of arsenic and were used by the City to meet the daily water demand of

approximately 120,000 gpd. Well 2, located adjacent to an active pasture at Connor’s Ranch, drew water 

from the Madison River, which was rich in arsenic from the upflow of geothermal water at Yellowstone 

National Park. Therefore, Well 2 was designated for this demonstration study. Prior to startup of the 

arsenic treatment system, Well 2 had been used only in the summer for cemetery irrigation for 5 to 8 

hr/day and 3 day/week. After startup, the treated water from Well 2 also was used to supply water to the 

distribution system.

Well 2 was 12.5-in in diameter and 150 ft deep with a screened interval extending from 75.5 to 150 ft 

below ground surface (bgs). The static water table was at 18 ft bgs. Well 2 was equipped with a 30-

horsepower (hp) submersible pump rated for 250 gpm at 85 psi of total dynamic head (TDH). Figure 4-1 

shows the pre-existing Well 2 pump house, which housed the wellhead piping, a pressure gauge, and a 

sample tap (Figure 4-2). Raw water from Well 2 was not treated prior to the demonstration study. 

An onsite sewer system discharged wastewater into a lagoon and then the Madison River during the 

summer months. Designed to serve a population of 2,200 people, the lagoon was composed of two 7-acre 

cells with depths ranging from 3.5 to 5 ft.

Figure 4-1. Pre-existing Well 2 Pump House
16

Figure 4-2. Interior Piping of Well 2 Pump House

4.1.2 Source Water Quality. Samples of Well 2 water were collected by Battelle on November 

30, 2004, during the introductory meeting for this demonstration project. The source water was filtered 

for soluble arsenic, iron, manganese, uranium, and vanadium, and then speciated for As(III) and As(V) 

using the field speciation method modified from Edwards (1998) by Battelle (Wang et al., 2000). In

addition, pH, temperature, DO, and ORP were measured onsite using a WTW Multi 340i field meter.

Table 4-1 summarizes the analytical results of the Well 2 source water sampling and those provided by 

the facility for the demonstration site selection and by the selected technology vendor (Kinetico). 

Historical data collected by MT DEQ from July 1993 through July 1998 also are included in the table. 

Overall, Battelle’s data are comparable to those provided by other parties with the exception of a few 

parameters provided by the facility. Well 2 had not been sampled by MT DEQ since 1998 as it was not

used as a drinking water well nor connected to the City’ distribution system.

The treatment system for the Three Forks site included iron addition, adsorption/coprecipitation, and 

Macrolite® pressure filtration. Several factors, such as arsenic speciation, iron concentration, pH, 
17

Table 4-1. Three Forks, MT Well 2 Source Water Data

Parameter Unit

Facility

Data

Kinetico

Data

Battelle

Data

MT DEQ

Data(a)

Date NA 10/22/03 11/30/04 07/07/93–07/21/98

pH S.U. 7.4 7.4 7.5 NA

Temperature °C NA NA 11.3 NA

DO mg/L NA NA 5.2 NA

ORP mV NA NA 62 NA

Total Alkalinity (as CaCO3) mg/L NA 236 260 NA

Hardness (as CaCO3) mg/L 246 185 205 NA

Turbidity NTU NA NA 0.2 NA

TDS mg/L 692 NA 292 NA

TOC mg/L 65(b) NA 0.8 NA

Nitrate (as N) mg/L 11.5 <1.0 0.4 0.42

Nitrite (as N) mg/L NA NA <0.01 <0.005

Ammonia (as N) mg/L NA NA <0.05 NA

Chloride mg/L 19.0 19.7 17.0 NA

Fluoride mg/L NA 2.2 2.2 0.2–2.4

Sulfate mg/L NA 18 18 23

Silica (as SiO2) mg/L 49.0 49.2 48.7 NA

Orthophosphate (as P) mg/L 0.86 <0.5 <0.06 NA

As (total) μg/L 72.0 85.0 64.3 60–78

As (total soluble) μg/L NA NA 63.7 NA

As (particulate) μg/L NA NA 0.6 NA

As(III) μg/L NA NA 1.3 NA

As(V) μg/L NA NA 62.4 NA

Fe (total) μg/L <30 <30 <25 NA

Fe (soluble) μg/L NA NA <25 NA

Mn (total) μg/L NA <10 <0.1 NA

Mn (soluble) μg/L NA NA <0.1 NA

U (total) μg/L NA NA 3.6 NA

U (soluble) μg/L NA NA 3.8 NA

V (total) μg/L NA NA 8.0 NA

V (soluble) μg/L NA NA 8.4 NA

Na (total) mg/L NA 47.0 43.9 NA

Ca (total) mg/L NA 52.0 59.3 NA

Mg (total) mg/L 13.1 13.5 13.7 NA

(a) MT DEQ historical data collected from 1993 through 1998 tabulated in Table 4-2.

(b) Data questionable.

NA = not analyzed

turbidity, total organic carbon (TOC), and competitive anions, may affect the system performance. The 

results of the source water assessment and implications for water treatment are discussed below.

Arsenic. Total arsenic concentrations ranged from 60 to 85 μg/L. Based on the November 30, 2004, 

speciation results, arsenic existed almost entirely in the soluble form. Of the soluble fraction, 1.3 μg/L 

existed as As(III) and 62.4 μg/L as As(V). Therefore, As(V) was the predominant species and 

prechlorination for the oxidation of As(III) to As(V) was not required for treatment. Prechlorination was 

used for disinfection purposes through the treatment system and to maintain chlorine residuals in the 

distribution system.
18

The presence of As(V) as the predominant species is consistent with the relatively high DO level of 5.2 

mg/L measured for the same sample. The ORP reading was 62 mV, somewhat lower than what would be 

expected for an oxidizing water. ORP readings were carefully monitored during the performance 

evaluation study.

Iron and Manganese. The source water did not contain detectable levels of iron or manganese. 

Therefore, adsorptive media would be ideal candidates for this source water. However, because of 

concerns over the O&M cost, the City decided to choose coagulation/filtration using FeCl3 rather than 

adsorptive media. For effective arsenic removal via the coagulation/filtration process, the iron 

concentration should be 20 times the arsenic concentration (Sorg, 2002). The treatment process relied

upon adsorption and coprecipitation of As(V) onto/with iron solids.

Other Water Quality Parameters. The pH range of 7.4 to 7.5 was within the target range of 5.5 to 8.5 

for arsenic removal via adsorption/coprecipitation onto/with iron solids. Results of other water quality 

parameters shown in Table 4-1 are comparable with exception to the results provided by the facility for 

nitrate (i.e., 11.5 mg/L), orthophosphate (i.e., 0.86 mg/L), total dissolved solids (TDS) (i.e., 692 mg/L), 

and TOC (i.e., 65 mg/L). These values are all significantly higher than those provided by other parties. 

The extremely high TOC was believed to be an error. 

The raw water also was sampled by MT DEQ for heavy metals, such as antimony, barium, beryllium, 

cadmium, chromium, mercury, nickel, selenium, and thallium (see Table 4-2). These metals were not 

detected except for antimony (i.e., 0.003 mg/L) and barium (i.e., 0.02 mg/L) on one occasion.

Table 4-2. Three Forks, MT Historic Water Quality Data

Parameter Unit Well 2 Raw Water Data

Date 07/07/93 07/05/94 09/20/94 09/11/95 06/19/96 07/21/98

Nitrate (as N) mg/L NA NA NA NA 0.42 NA

Nitrite (as N) mg/L NA NA NA NA ND NA

Nitrate + Nitrite (as N) mg/L 0.52 ND 0.13 0.19 0.42 0.44

Fluoride mg/L 2.4 NA NA NA 0.2 NA

Sulfate mg/L 23 NA NA NA 23 NA

Antimony mg/L 0.003 NA NA NA ND NA

Arsenic mg/L 0.06 NA NA NA 0.078 NA

Barium mg/L 0.02 NA NA NA ND NA

Beryllium mg/L ND NA NA NA ND NA

Cadmium mg/L ND NA NA NA ND NA

Chromium mg/L ND NA NA NA ND NA

Mercury mg/L ND NA NA NA ND NA

Nickel mg/L ND NA NA NA ND NA

Selenium mg/L ND NA NA NA ND NA

Thallium mg/L ND NA NA NA ND NA

Source: MT DEQ.

NA = not analyzed; ND = not detected

4.1.3 Distribution System. The distribution system for the City of Three Forks consisted of an 8-

mile closed distribution line supplied by Wells 5, 6, 8, and 9 prior to the demonstration study. The 

distribution system was extended to include Well 2 after startup of the arsenic treatment system. 

According to the utility operator, the distribution system piping was a combination of 6-, 8-, 10-, and 12-

in ductile iron, polyvinyl chloride (PVC), and asbestos cement. The service lines were galvanized, 
19

copper, and polyethylene piping. Well water was pumped into a 1,000,000-gal water tank (Figure 4-3)

immediately adjacent to the treatment building for storage and distribution. The three locations that were

selected for monthly baseline and distribution system water sampling were impacted by all five wells.

The City of Three Forks sampled water from the distribution system for several parameters: monthly at 

two residences for bacterial analysis; once every three years at 10 residences for LCR analysis; and once 

every nine years for asbestos analysis. Wells 5, 6, 8, and 9 also were sampled yearly for nitrate and 

nitrite; once every three years for arsenic, volatile organic compounds (VOCs), synthetic organic 

compounds (SOCs), inorganics, and periodically for radionuclides.

Figure 4-3. One-million Gallon Water Tank by Treatment Building

4.2 Treatment Process Description

The arsenic treatment system installed was a Kinetico coagulation/filtration system that included 

Macrolite® pressure filtration. Macrolite® is a ceramic media manufactured by Kinetico approved for use 

in drinking water applications under NSF International (NSF) Standard 61. As claimed by the vendor, the 

spherical, low density and chemically inert media is designed to allow for filtration rates up to 10 gpm/ft2

. 

The physical properties of this media are summarized in Table 4-3.

Figure 4-4 is a schematic of the Macrolite® FM-248-AS arsenic removal system. The treatment system 

was composed of two chemical feed systems for chlorine and FeCl3, two contact tanks (arranged in 

parallel), two pressure filtration vessels (arranged in parallel), and associated instrumentation to monitor 

inlet and outlet pressure, system flowrate, backwash flowrate, and backwash wastewater turbidity. The 

system also was equipped with a central control panel that housed a touch screen operator
20

Table 4-3. Properties of 40/60 Mesh Macrolite® Media

Property Value

Color Taupe, Brown, Grey

Thermal Stability (

o

F) 2000 

Uniformity Coefficient 1.1

Sphere Size Range (in) 0.014–0.009 

Bulk Density (g/cm3 or lb/ft3) 0.86 or 54 

Specific Gravity 2.05

interface panel (OIP), a programmable logic controller (PLC), a modem, and an uninterruptible power 

supply (UPS). The Allen Bradley PLC automatically controlled the system by actuating PVC pneumatic 

valves using a 7.5-hp compressor depending on various inputs and outputs of the system and 

corresponding PLC setpoints. The system featured schedule 80 PVC solvent bonded plumbing and all 

necessary isolation and check valves and sampling ports. The system’s design specifications are 

summarized in Table 4-4.

Figure 4-4. Schematic of Kinetico’s Macrolite® Arsenic Removal System

The treatment technology includes the following major process steps and system components:

• Intake. Raw water was pumped from Well 2, which was equipped with a 30-hp submersible 

pump rated for 250 gpm at 85 psi TDH to the distribution system. The well pump was 

controlled by a pair of high/low level sensors in the 1,000,000-gal water storage tank. 

• Chlorination. The prechlorination system was used for disinfection purposes through the 

treatment system and to maintain a total chlorine residual level of approximately 0.9 mg/L (as 

Cl2) in the distribution system. MT DEQ requires that a minimum of 0.2 to 0.5 mg/L (as Cl2) 
21

Table 4-4. Design Specifications of Macrolite® System

Parameter Value Remarks

Influent Specifications

Peak Flowrate (gpm) 250 –

Arsenic Concentration (μg/L) ≤ 90 –

Iron Concentration (μg/L) <25 –

Pretreatment

Chlorine Residual (mg/L [as Cl2]) 0.9 From 12.5% NaOCl stock

Iron Addition (mg/L) 2.0 From 35% FeCl3 stock (diluted 1:4)

Contact

Number of Tanks 2 –

Configuration Parallel –

Tank Size (in) 63 D × 86 H –

Contact time (min) 5 –

Filtration

Number of Vessels 2 –

Configuration Parallel –

Vessel Size (in) 48 D × 72 H –

Media Volume (ft3/vessel) 25 –

Media Bed Depth (in) 24 –

Peak Filtration Rate (gpm/ft2) 10 –

Backwash

Pressure Drop (psi) 10–12 Across a clean bed

Initiating Pressure (psi) 20 Across bed at end of filter run

Initiating Standby Time (hr) 48 –

Initiating Service Time (hr) 24 –

Hydraulic Loading Rate (gpm/ft2) 8–10 100 to 125 gpm

Duration (min/vessel) 10–15 –

Turbidity Setpoint (NTU) 10 To terminate backwash

Wastewater Production (gal/event) 2,000–3,750 From backwashing both vessels

Effluent Specifications

 Peak Flowrate (gpm) 250 Typically expected

 Maximum Daily Production (gpd) 360,000 Based on peak flowrate, 24 hr/day

 Hydraulic Utilization (%) 6–21 Estimate based on expected demand(a)

 Arsenic Concentration (μg/L) <10 –

 Iron Concentration (μg/L) <25 –

(a) Operation of approximately 10 hr/week during winter and 35 hr/week during summer.

of free chlorine residuals be maintained at distant points of a distribution system. The 

chlorine feed system (Figure 4-5) consisted of a 55-gal high-density polyethylene (HDPE) 

day tank containing a 12.5% NaOCl solution, a 0.04-hp chemical feed pump (LMI B711-

490HI model) with a maximum flowrate of 1.6 gal/hr (gph), a maximum pressure of 150 psi, 

and a 66-gal polyethylene spill containment pallet (U.S. Plastic model 2316). The feed pump 

was energized only when the well pump was on.

• Iron Addition. FeCl3 was added at a target dosage of approximately 2.0 mg/L (as Fe) to 

remove soluble As(V). The FeCl3 feed system consisted of a 55-gal HDPE day tank 

containing a solution mixed from a 35% FeCl3 stock, a 1/20-hp, 1,550 rotations per minute 

(rpm) overhead mixer (Pulsafeeder model J40456-F-M-TE-H/WRD/Vinyl), and a chemical 

feed pump (Pulsatron LPH5MA-VTC3-XXX) rated at 3.15 gph nominal flowrate and 150 psi 

maximum pressure.
22

Figure 4-5. Chemical Feed Systems

The iron and chlorine addition systems shared the same spill containment pallet as shown in 

Figure 4-5. The chemical feed pump was energized only when the Well 2 pump was on.

• Adsorption/Coprecipitation. Two 63-in × 86-in FRP tanks arranged in parallel provided 5 

min of contact time to enhance the formation of arsenic-laden iron solids prior to pressure 

filtration. Each 1,160-gal tank had a 6-in top and a 6-in bottom flange connecting to the exit 

and inlet piping, respectively, for an upflow configuration. Figure 4-6 shows the two contact

tanks along with the inlet and exit piping.

• Pressure Filtration. Removal of arsenic-laden iron particles from the contact tank effluent 

was achieved via downflow filtration through two 48-in × 72-in FRP pressure filtration 

vessels configured in parallel. The vessels were floor mounted and piped to a valve rack 

mounted on a welded, stainless steel frame (Figure 4-7). Each filtration vessel was filled with 

approximately 24 in (or 25 ft3

) of 40/60 mesh Macrolite® media supported by fine garnet 

underbedding filled to 1 in above a stainless steel wedge-wire underdrain with 0.006-in slots. 

The flow through each vessel was regulated to 125 gpm with a flow-limiting device. The 

normal system operation with both vessels online provided a total system flowrate of 250 

gpm. 
23

Figure 4-6. Contact Tanks with Inlet and Exit Piping

Figure 4-7. Filtration Vessels and Valve Rack
24

• Filter Backwash. At a 10-gpm/ft2 loading rate and a 24-in bed depth, the anticipated 

pressure drop across a clean Macrolite® filter bed was 10 to 12 psi. The filters were

automatically backwashed in succession in an upflow mode based on a service time, a 

standby time, or a Δp setpoint. Initial design specified that during each backwash cycle, 

water was drained from the first filtration vessel, which was then sparged with air at 150 psi 

for 2 min using a Speedaire Model 1WD61 air compressor. After a 25-min settling period, 

the filtration vessel was backwashed with treated water from the distribution system until the 

backwash wastewater reached a desired turbidity threshold setpoint (e.g., 20 nephelometric 

turbidity units [NTU]) as measured by an inline HachTM turbidimeter (Figure 4-8). These 

design values were altered throughout the course of the demonstration study as discussed in 

Section 4.4.3.1. The filtration vessel then underwent a filter-to-waste rinse before returning 

to service, and the second filtration vessel was backwashed thereafter. Shortly after system 

startup, it was determined that a booster pump needed to be installed to achieve the required 

backwash pressure from the treated water line due to the treatment system being constructed 

at the same elevation as the 1,000,000-gallon storage tank. To remedy this, a 7.5-hp booster 

pump (Blador 11SH model) was installed.

Figure 4-8. HachTM Turbidimeter for Control of Backwash Duration

As originally designed, the backwash wastewater was discharged to a recycling tank. The 

backwash recycle system (Figure 4-9) consisted of a 92-in diameter, 3,000 gal cone-shapedbottom holding tank and a 5-hp Blador G&L pump (Model SSV). Upon completion of a

backwash, wastewater in the backwash wastewater tank was allowed to settle for a period of 

time (Section 4.4.3.1) before the supernatant was pumped at 100 to 120 gpm through a 20-in,

5-μm bag filter back to the head of the treatment train. Two weeks after commencement of 
25

the performance evaluation study, the City installed piping and a manual diverter valve to 

drain the recycle tank supernatant directly to the sewer. This was done to help 

isolate/identify factors that adversely affected the treatment results (i.e., apparent 

breakthrough of soluble As[V] and arsenic-laden iron particles from the filters) observed 

during the first two weeks of system operations. Wastewater recycling was never put back 

into service throughout the remainder of the evaluation study. Had recycling been 

implemented as designed, the sludge that settled and accumulated in the recycle tank would 

be removed periodically from the bottom of the tank through a sludge removal port.

Figure 4-9. Backwash Recycle System

• Water Storage and Distribution. After leaving the treatment train, the treated water was 

transferred into the 1,000,000-gal storage tank located next to the treatment building. The 

stored effluent was allowed to flow to the distribution system based on demand. 

4.3 Treatment System Installation

4.3.1 System Permitting. The system engineering package, prepared by Kinetico and its 

subcontractor, Morrison Maierle, Inc., included a system design report, a general arrangement and piping 

and instrumentation diagram (P&ID), electrical and mechanical drawings and component specifications, 
26

and building construction drawings detailing connections from the system to the inlet piping and the 

City’s water and sanitary sewer systems. The engineering package was certified by a Professional 

Engineer registered in the State of Montana and submitted to MT DEQ for review and approval on 

November 2, 2005. A water supply construction permit was issued by MT DEQ on January 26, 2006. 

The permit approval letter required that a complete set of record drawings be signed, stamped, certified 

(that the system was constructed in accordance with approved plans and specifications), and submitted to 

MT DEQ within 90 days following completion of the construction. 

4.3.2 Building Construction. A permit for building construction was approved by MT DEQ on 

April 7, 2006. Construction began on April 13, 2006 and was completed on July 31, 2006. The building 

was 15 ft × 29 ft with sidewall and roof peak heights of 17 and 22 ft, respectively. The foundation had a 

102-in-depth overlain with a 6-in concrete slab. Wastewater discharge was facilitated with a 1,500-gal 

underground sump that emptied by gravity into the sanitary sewer. In addition to electrical and plumbing 

connections, a phone line also was installed to enable the equipment vendor to dial into the modem in the 

control panel for any troubleshooting. Figure 4-10 shows photographs of the constructed building.

Figure 4-10. Treatment System Building

4.3.3 System Installation, Startup, and Shakedown. The treatment system was delivered to the 

site on May 30, 2006 (see Figure 4-11). The vendor, through its subcontractor, performed the off-loading 

and installation of the system, including connections to the entry and distribution piping and electrical 

interlocking. System installation, hydraulic testing, and media loading were completed on June 5, 2006, 

but system startup and shakedown were delayed due to the absence of power to the building; power 

connection was completed on June 26, 2006. Startup/shakedown activities began on July 11, 2006, but 

ended prematurely due to insufficient pressure in the treated waterline for backwash (Section 4.2). A 20-
27

hp Goulds 11SH model booster pump was then procured and installed by the City under Kinetico’s

guidance and became operational on October 25, 2006. Kinetico technicians remained onsite to perform 

system startup and shakedown, which lasted until October 30, 2006. The shakedown and startup 

activities included PLC testing, instrument calibration, prolonged backwashing to remove Macrolite®

media fines, chlorine disinfection and residual testing, and operator training on system O&M. 

Two Battelle staff members traveled to the site to perform system inspections and operator training on 

sample and data collection on November 28 and 29, 2006. As a result of the system inspections, several 

punch-list items were identified and are summarized in Table 4-5. 

Figure 4-11. Treatment System Delivery at Three Forks, MT Site

4.4 System Operation

4.4.1 Service Operation. System operational parameters are tabulated and attached as Appendix 

A with key parameters summarized in Table 4-6. The performance evaluation study began on November 

27, 2006, and ended on February 8, 2008, with the treatment plant treating approximately 30,499,000 gal 

of water. The amount of water treated was based on readings from a flow meter/totalizer installed at the 

effluent side of the pressure filters.

Through the study period, the system operated for a total of 2,543 hr, based on well pump hour meter 

readings from November 27, 2006, to February 16, 2007, and filter run time from February 16, 2007, to 

February 8, 2008. The system operated for 2 to 7 days per week for a total of 284 days, excluding some

weekends and weekdays when the system was not operating (see Appendix A) and some weekdays when 
28

Table 4-5. System Inspection Punch-List Items

Item 

No. Punch-List Item Description Corrective Action(s) Taken

Resolution 

Date

1 Check programming to determine 

cause for Vessel A’s returning to 

service only after reaching 45 min 

delay time following backwashing 

• Programming checked; Vessel A returned to 

service upon completion of backwashing

12/01/06

2 Check/revise maximum backwash 

time programming

• Programming checked, no further action required 12/01/06

3 Adjust recycle flowrate and low 

backwash flowrate setpoint to meet 

State requirements and provide 

effective backwashing

• Recycle flowrate reduced from 44 to 20 gpm

• Low backwash flowrate setpoint increased from 

20 to 100 gpm

12/01/06

4 Adjust delay time for backwash 

wastewater recycling 

• Increased delay time from 45 to 240 min to allow 

for settling of backwash solids

12/08/06

5 Repipe influent piping (Figure 4-

12), which was not installed per 

Drawing 2-1251-01

• Raw water sample tap relocated to >10 ft from 

chemical addition points; Chlorine and ferric 

chloride injection points relocated further 

downstream (Figure 4-12)

12/11/06

6 Reset differential pressure setpoint 

to 25 psi

• A differential pressure trigger lockout added to 

allow for increased differential pressure during 

backwash

12/11/06

7 Adjust/improve backwash water 

recycling programming

• Further explanation given on PLC/alarm interface

• Total maximum backwash time reduced to 20 min 

12/15/06

8 Repair air relief valves, which 

leaked water constantly

• Gaskets of air relief valves replaced 12/15/06

9 Repair leaky recycle piping • Piping repaired by City 12/15/06

the system or Well 2 was taken offline for repair and/or maintenance (see Table 4-7). To curb the 

elevated arsenic concentrations in the pressure filter effluent, the City implemented an increased blending 

scenario by reducing the operating schedule for Well 2 from 5–7 day/week to only 3 day/week on 

Mondays, Wednesdays, and Fridays. The average daily operating time was 8.9 hr/day, representing a 

daily use rate of 37%. With 30,499,000 gal of water treated, the average daily demand was 107,400 gpd, 

compared to 120,000 gpd reported by the facility prior to this demonstration study. 

System flowrates were tracked by both instantaneous readings of the flow meter/totalizer installed at the 

effluent side of the pressure filters and calculated values based on readings of the flow totalizer and well 

hour meter or filter run time. As shown in Table 4-6, instantaneous flowrate readings ranged from 140 to

216 gpm and averaged 202 gpm, which is comparable to the calculated value of 206 gpm, but 19.2% 

lower than the design value of 250 gpm. As a result, the average contact time in the two contact tanks 

increased from the design value of 5 to 6.2 min and the average filtration rate through each pressure filter 

decreased from the design value to 10.0 to 8.0 gpm/ft2

. 

Contact time was initially recommended by the vendor for 5 min, which was determined to be sufficient 

to contact arsenic with precipitating iron particles and allow iron flocs to form. However, competition 

from silicates for available adsorptive sites as well as interaction of Fe(III) with silicates that cause the 

formation of soluble polymers and highly dispersed colloids (Iler, 1979; Robinson, et al., 1992) might 

have led to greater contact time needs than provided by the treatment system design. In addition, despite 

lower than the designed hydraulic loading at 8.0 gpm/ft2 (compared to the design value of 10 gpm/ft2

), 

breakthrough of both iron and arsenic particulates was experienced (see Section 4.5.2).
Figure 4-12. Relocation of IN Sampling Location and Chemical Inject Points
Table 4-6. Treatment System Operational Parameters

Parameter

11/27/06–02/08/08

Average [Range]

Pretreatment

NaOCl Dosage (mg/L [as Cl2]) 2.4 [0.3–7.1]

FeCl3 Dosage (mg/L [as Fe]) 2.1 [0.2–6.1]

Coagulation/Filtration

Total Operating Time (hr) 2,543

Total Operating Days (day) 284

Average Daily Operating Time (hr) 8.9

Throughput (gal) 30,499,000

Average Daily Demand (gal) 107,400

Instantaneous Flowrate (gpm) 202 [140–216]

Calculated Flowrate (gpm) 206 [77–261]

Contact Time (min) 6.2 [5.8–8.9]

Filtration Rate (gpm/ft2) 8.0 [5.6–8.6]

∆p across Each Filtration Vessel (psi) 12 [5.0–31]

∆p across System (psi) 25 [19–44]

Filter Run Time between Backwash Cycles (hr) 8.3 [0.1–21.1]

Throughput between Backwash Cycles (gal/event) 101,325 [1,128–580,376]

Backwash

Frequency (occurrence/vessel/day) 1 [0–5]

Number of Cycles (Vessel A/Vessel B) 301/303

Flowrate (gpm)(a,b) 114 [85–133]

Hydraulic Loading Rate (gpm/ft2) 9.1 [6.7–10.6]

Duration (min/vessel) 10 [9–13]

Backwash Volume (gal/vessel/cycle) 1,167 [1,100–1,300]

Filter to Waste Volume (gal/vessel/cycle) 700

Wastewater Produced (gal/vessel/cycle) 1,867 [1,800–2,000]

(a) Average of both vessels’ calculated backwash flowrate. Outlier of 44 gpm 

on 12/11/06 removed from calculations.

(b) Outlier of 44 gpm backwash lasting for 27 and 25 min for Vessels A and B, 

respectively, removed from average calculation.

Table 4-7. Unscheduled System Downtime

Date

Number of Days 

with System 

off/down

Cause(s) of System

off/down

12/13/06 1 Influent piping modifications and recycling 

tank piped to sewer

02/14/07 1 Communication between plant and well down

02/15/07 0 Coaxial cable replacement and hand switches 

added to well (system remained online)

05/22–23/07 2 Well 2 offline for repairs

05/28–29/07 2 Well 2 offline for repairs

07/08–09/07 2 A 480 V, 65 amp breaker at Well 2 broken due 

to storm

08/25–27/07 3 Plant and Well 2 shut down due to low 

backwash flow alarm

01/14–21/08 7 Well 2 offline for repairs

Total 18
31

Δp readings ranged from 5 to 31 psi across each filter and from 19 to 44 psi across the system. As 

expected, Δp readings increased with increasing duration of the filter runs (Figure 4-13), presumably 

caused by the buildup of arsenic-laden iron solids within the filter media. Figure 4-13 also presents data 

for the Δp behavior with the filter runs using polymer amended systems (Section 4.5.2). It does not 

appear from these data that polymer addition significantly altered the trend of pressure drop with filter run 

time during the filter service cycles. Data in Figure 4-13 also indicate that backwash was effective in 

restoring the filters, as evidenced by the relatively low differential pressure readings, i.e., 5 to 8 psi, 

immediately after backwashing. Backwash will be further discussed in Section 4.4.3. 

Filter run times between backwash cycles ranged from 0.1 to 21.1 hr and averaged 8.3 hr (Figure 4-14). 

The corresponding throughputs ranged from 1,128 to 580,376 gal/event and averaged 101,325 gal/event. 

Each backwash cycle consumed an average of 3,734 gal of treated water, which represents 3.8% of the 

average throughput between backwash cycles. These numbers are based on the time in service between 

backwash cycles and the average daily flowrate (taken from the totalizer) from that day. 

0

10

20

30

40

50

60

0 2 4 6 8 10 12 14 16 18 20

Run Time Since Last Backwash (hr)

dP Across Tank (psig)

TA with FeCl3

TB with FeCl3

TA with FeCl3/Polymer Blend

TB with FeCl3/Polymer Blend

Figure 4-13. Differential Pressure vs. Filter Run Time
32

0

5

10

15

20

25

10/10/0611/29/06

1/18/07

3/9/07

4/28/07

6/17/07

8/6/07

9/25/07

11/14/07

1/3/08

2/22/08

4/12/08

Date

Run Time (hr)

Tank A Tank B

Figure 4-14. Vessels A and B Service Time between Backwash Cycles

4.4.2 Chlorine and Iron Additions. Chemical pretreatments consisted of prechlorination and iron 

addition. Prechlorination was used for disinfection purposes; chlorine dosages ranged from 0.3 to 7.1 

mg/L (as Cl2) and averaged 2.4 mg/L (as Cl2) (Table 4-6 and Figure 4-15). Iron addition was used for 

As(V) removal. A 35% FeCl3 stock solution was diluted with a volume ratio of 1:4 and then fed prior to 

the contact tanks. Throughout the study period, iron dosages ranged from 0.2 to 6.1 mg/L (as Fe) and 

averaged 2.1 mg/L (as Fe), compared to the target dosage of 2.0 mg/L (as Fe) (Table 4-6 and Figure 4-

15). Chlorine and iron dosages were calculated based on daily chemical consumption (by changes of 

solution levels in the respective chemical day tanks) and daily flow.

As shown in Figure 4-15, extensive scattering of chemical dosages was observed during both NaOCl and 

FeCl3 additions. Because the speed and stroke length settings of the chemical feed pumps were seldom 

adjusted, more consistent dosages should have been achieved especially with relatively constant system 

flowrates experienced during the study period. Therefore, the scattering observed was believed to be due 

mainly to inconsistencies or inaccuracies in solution level measurements, which could significantly 

impact the calculated dosages. Chemical consumption and dosage data could be better obtained by the 

use of a drum scale.
33

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

10/10/0611/29/0601/18/0703/09/0704/28/0706/17/0708/06/0709/25/0711/14/0701/03/0802/22/0804/12/08

Date

Chemical Dose (mg/L)

FeCl3 (mg/L as Fe)

NaClO (mg/L as Cl2)

Figure 4-15. Chlorine and Ferric Chloride Dosages Over Time

4.4.3 Backwash Operation. As noted in Section 4.2, backwash could be initiated by a service run 

time, a standby time, or a Δp setpoint. The vendor recommended in the original design documentation 

that backwash be initiated: (1) when Δp across a single filter had reached 20 psi, (2) after the system had 

achieved 24 hr of service time, or (3) after the system had sat idle for 48 hr, whichever occurred first. 

Since system startup, these and several other settings had been adjusted a number of times based on 

system performance and filter effluent water quality data. Further, backwash cycles were manually 

initiated during the first five months of system operation and manual backwash was discontinued on April 

16, 2007. Table 4-8 summarizes adjustments to PLC settings throughout the study period. 

Since system startup, Vessels A and B were backwashed 301 and 303 times, respectively. Among the 

284 days when the system was operational, Vessels A and B were backwashed once a day for 207 and 

202 days, respectively. There were days when the vessels were either not backwashed (31 and 34 days, 

respectively), or backwashed two times a day (43 and 44 days, respectively) or even three times a day 

(three days each). On February 5, 2007 when the operator tried to initiate backwash from offsite, Vessel 

B was backwashed consecutively for five times due to unknown control issues with the City’s system 

control and data acquisition (SCADA) system. The system had to be restarted to resume normal 

operations. Figure 4-16 shows a backwash frequency histogram.

The backwash duration for each filter was affected by the minimum and maximum backwash time 

settings and the ability of backwash wastewater to meet the turbidity threshold setting as measured by the

in-line HachTM turbidimeter. If backwash wastewater failed to meet the set threshold value prior to

reaching the maximum backwash time, the backwash failure alarm had to be acknowledged and a 

successful backwash cycle completed before the vessel could return to the service mode. Each backwash

was followed by a 3-min filter-to-waste (FTW) step to rinse off any left-over particles from the filter. 
34

Table 4-8. Summary of PLC Settings for Backwash Operations

Parameter (for Each Vessel)

Date of Adjustments

11/03/06(a)11/14/0611/22/0611/29/0612/01/0612/07/0612/08/0604/16/0707/17/0707/24/0707/30/0708/08/0708/20/07

Drain Time (min) 5 5 5 5 5 5 5 5 5 5 5 5 5

Service Time Trigger (hr) 24 20 20 20 20 20 20 8 24 24 5 8 6

Standby Time Trigger (hr) 48 72 80 80 80 80 96 96 96 96 96 96 96

∆p Trigger (psi) 40 40 40 40 40 25 25 25 25 25 25 25 25

Minimum Backwash Time (min) 15 10 10 10 10 10 10 10 10 10 10 10 10

Maximum Backwash Time (min) 45 25 25 25 25 20 20 20 20 20 20 20 20

Turbidity Threshold (NTU) 12 12 15 15 15 15 20 20 20 25 30 30 30

Low Flowrate Threshold (gpm) 20 20 100 100 100 100 100 100 100 100 100 100 100

Filter-to-Waste Time (min) 3 3 3 3 3 3 3 3 3 3 3 3 3

Recycle Pump Run Time Delay (min) 25 25 45 45 240 45 240 240 240 240 240 240 240

Recycle Pump Flowrate (gpm) 44 44 44 20 44 20 20 20 20 20 20 20 20

(a) Initial field settings set by vendor technicians during system shakedown and startup.

0

50

100

150

200

250

Backwashes per Day

Number of Occurances

Tank A 31 207 43 3 0 0

Tank B 34 202 44 3 0 1

10 21 32 34 54 65

Figure 4-16. Backwash Frequency Histogram

The amount of backwash wastewater produced ranged from 1,100 to 1,300 gal/vessel and averaged 1,167 

gal/vessel. This amount reflects an average backwash flowrate of 114 gpm and an average backwash 

duration of 10 min (compared to the design values of 100 to 125 gpm and 10 to 15 min, respectively). 

Including an additional 700 gal/vessel produced during the 3-min FTW step, the total amount of 
35

wastewater produced was 1,867 gal/vessel or 3,734 gal for both vessels. One backwash occurred on 

February 11, 2007 and lasted for 27 and 25 min for Vessels A and B, respectively and, therefore, was not 

included in the average calculation for the wastewater produced. The total amount of wastewater 

produced was equivalent to 3.8% of the amount of water treated. However, as discussed in Section 4.5.2, 

because the useful filter run length (i.e., the maximum filter run length which consistently yielded <10 

μg/L total arsenic and <300 μg/L total iron in the effluent) was much shorter than the actual filter run 

lengths observed during the study, the percentage of processed water used for backwashing would have

been much higher than 3.8% had the useful filter run length been implemented throughout the study.

4.4.3.1 PLC Settings. As shown in Table 4-8, the initial backwash PLC settings set by vendor 

technicians on November 3, 2006 during system shakedown and startup were quite different from those in 

the original design documentation and those for several similar Macrolite® pressure filtration systems 

already operational at other arsenic demonstration sites (Condit and Chen, 2006; Condit and Chen, 2008; 

Valigore et al., 2008a). Six subsequent modifications were made on November 14, 22, and 29, 2006, as 

well as December 1, 7, and 8, 2006, by the facility operator and the vendor based on Battelle’s punch-list 

items summarized during the November 28 and 29, 2006, trip to the facility. The modifications made 

included:

• Decreasing the setpoint for the Δp trigger to 25 psi to more closely match the original design 

value.

• Decreasing the setpoint for the service time trigger to 20 hr to reduce particulate 

breakthrough from the filters. 

• Increasing the setpoint for the standby time trigger to 96 hr to reduce the number of backwash 

cycles triggered based on standby time.

• Decreasing the maximum backwash time to 20 min and increasing the turbidity threshold to 

20 NTU to reduce wastewater production.

• Increasing the low flowrate threshold to 100 gpm to more closely match the intended 

backwash flowrate of 100 to 125 gpm.

The facility operator decided to manually initiate backwash on a daily basis during the first five months of 

system operation; automatic backwash triggers were utilized only after April 16, 2007. On November 29, 

2006, it was noticed that Vessel A after a backwash cycle would not return to service until it had reached 

the 45-min recycle pump delay time. This programming problem was resolved by the vendor through 

dialing to the PLC.

Since April 16, 2007, other changes to the PLC were made, including 1) temporarily increasing the 

setpoint for the service time trigger to 24 hr to accommodate a special study on the use of the C-05 

iron/organic polymer blend, and then decreasing the setpoint to 5 to 6 hr to continue to address issues 

with particulate breakthrough, and 2) increasing the turbidity threshold from 20 to 30 NTU due to filter 

clogging caused by C-05 dosing.

4.4.3.2 Backwash Flowrates. Backwash flowrates ranged from 85 to 133 gpm and averaged 114 

gpm, which was within the range of the design values of 100 to 125 gpm. There were only two backwash 

instances where the backwash times were over 13 min and thus, the backwash flowrates were considered

sufficient for the backwash operation. 

4.4.4 Residual Management. Residuals produced by the Macrolite® Arsenic Removal System 

included backwash wastewater and FTW rinse water, which contained arsenic-laden solids. Backwash 
36

wastewater was analyzed for metals. As originally designed, 10% of the wastewater would be discharged 

via the sewer to a lagoon used for irrigation and the other 90% of the wastewater would be reclaimed after 

being passed through a bag filter. In June 2006, Battelle considered installing an additional totalizer after 

a three-way valve on the backwash recycle line in order to quantify the amounts of recycled water. 

Because the City decided to discharge the backwash wastewater directly to the lagoon via the sewer, the 

totalizer was not installed. 

4.4.5 Reliability and Simplicity of Operation. Inability to achieve acceptable arsenic removal 

due to inefficient coagulation/filtration of arsenic-laden particles, and backwash-related issues including 

PLC settings were the primary sources of concern during the study. The filter performance issues were 

not successfully resolved and the treatment system was not able to achieve the 10-μg/L arsenic MCL 

within reasonable service run lengths. Therefore, the City relied primarily on a blending scheme to meet 

the 10-μg/L MCL prior to entering the distribution system.

4.4.5.1 Pre- and Post-Treatment Requirements. Pretreatment consisted of the addition of chlorine 

and ferric chloride. Although unnecessary due to the oxidizing nature of source water, prechlorination 

was used for disinfection and maintaining a total chlorine residual in the distribution system. Iron 

addition, using a 35% FeCl3 stock (diluted 1:4) solution, was required to remove arsenic. Iron was added 

upstream of the contact tank within the treatment plant where solution levels were tracked daily.

4.4.5.2 System Automation. The treatment system was automatically controlled by the PLC in the 

central control panel. The control panel contained a modem and a touch screen OIP that facilitated 

monitoring of system parameters, changing of system setpoints, and checking the alarm status. Service 

time, standby time, and ∆p settings (Table 4-8) automatically determined when the filters were 

backwashed. The touch screen OIP also enabled the operator to manually initiate the backwash sequence. 

4.4.5.3 Operator Skill Requirements. Under normal operating conditions, the daily demand on the 

operator was about 30 min for visual inspection of the system and recording of operational parameters, 

such as pressure, volume, flowrate, and chemical usage on field log sheets. After receiving proper 

training during the system startup, the operator understood the PLC, knew how to use the touch screen 

OIP, and was able to work with the vendor to troubleshoot problems and perform minor onsite repairs. 

MT DEQ has five certification classes for water system operators (first to fifth class). First class covers 

all operators in operation of a system treating surface water using chemical coagulation, filtration and 

disinfection serving more than 20,000 people. Fifth class covers operators in operation of a system 

treating well water serving fewer than 100 people, with or without disinfection. The Three Forks operator 

possesses the third class certification, which covers operation of a system treating well water serving 

greater than 2,500 people with or without disinfection. 

4.4.5.4 Preventative Maintenance Activities. The vendor recommended several routine maintenance 

activities to prolong the integrity of the treatment system (Kinetico, 2006). Daily preventative 

maintenance tasks included recording pressures, flowrates, chemical drum levels, and visually checking 

for leaks, overheating components, proper manual valve positioning and pumps lubricant levels, and any 

unusual conditions. The vendor recommended weekly checking for trends in the recorded data that might 

indicate a decline in system performance, and semi-annually servicing and inspecting ancillary equipment 

and replacing worn components. Cleaning and replacement of sensors and replacement of o-ring seals 

and gaskets of valves were performed as needed.

4.4.5.5 Chemical Handling and Inventory Requirements. Chlorine and iron addition were required 

for disinfection and effective arsenic removal, respectively. The operator tracked the use of the chemical 

solutions daily (by volume), coordinated the supplies, and refilled the day tanks as needed. A 15% 
37

NaOCl solution, supplied in 55-gal drums by Hawkins, was transferred to the day tank and injected 

without dilution. A 35% FeCl3 stock solution, supplied in 350 lb drums by Hawkins, was diluted 1:4 in 

the 55-gal day tank prior to injection into raw water. The speed and stroke settings of the chemical pumps

were adjusted, as needed, to acquire the target chlorine residuals (as measured regularly with a Hach 

pocket colorimeter) and iron concentrations after the contact tanks. 

4.5 System Performance

The performance of the Macrolite® FM-248-AS Arsenic Removal System was evaluated based on 

analyses of water samples collected from the treatment plant, backwash line, and distribution system.

4.5.1 Treatment Plant Sampling. The treatment plant water was sampled on 11 occasions,

including one duplicate and three speciation sampling events, during the study. A complete set of the 

analytical results is tabulated and included in Appendix B. Table 4-9 summarizes the results for arsenic, 

iron, and manganese. Table 4-10 summarizes the results for other water quality parameters. The results 

of the water samples collected across the treatment plant are discussed below.

4.5.1.1 Arsenic and Iron. Figure 4-17 presents the results of three speciation events taken across the 

treatment train (at IN, AC, and TT locations). Figure 4-18 shows total arsenic concentrations measured 

across the treatment train. Total arsenic concentrations in raw water ranged from 59.8 to 96.7 μg/L and 

averaged 84.0 μg/L. Of the soluble fraction, As(V) was the predominant species averaging 74.5 μg/L 

with low levels of As(III) also present at 0.7 μg/L (on average). Comparatively low levels of particulate 

arsenic were present, averaging 4.2 μg/L.

Similar to the observation made during the initial site visit on November 30, 2004, source water from 

Well 2 was rather oxidizing, with DO concentrations ranging from 2.1 to 3.3 mg/L and averaging 2.6 

mg/L and ORP readings ranging from 239 to 334 mV and averaging 272 mV. These DO and ORP data 

support the speciation results, which indicate the presence of primarily soluble As(V). DO levels 

remained relatively constant throughout the treatment plant at 2.2 to 2.4 mg/L (on average). ORP 

readings increased significantly to 342 mV (on average) after chlorination and remained relatively 

constant thereafter at 330 to 400 mV.

Soluble As(V) and As(III) after the contact tanks averaged 8.7 μg/L and 0.8 μg/L, respectively. Following 

iron addition (Figure 4-19) and contact tanks, the majority of arsenic was present, as expected, in the 

particulate form at 71.3 μg/L as a result of adsorption and/or coprecipitation of As(V) with iron solids. 

The close-to-10 μg/L soluble As(V) concentrations measured after the contact tanks suggest the need for 

more iron, which, presumably, would produce more iron solids and shorten already short filter run times, 

as discussed in Section 4.5.2. 

The results of the first three weeks of treatment plant sampling indicated that total arsenic concentrations 

were only reduced to the range of 17.3 to 30.6 μg/L, significantly higher than the 10 μg/L MCL. Based 

on the November 29, 2006 speciation results, of the 28.3 μg/L total arsenic, 23.5 μg/L existed as 

particulate arsenic and 4.8 as soluble arsenic. This, together with the 936 μg/L particulate iron measured 

in the same sample, suggests breakthrough of arsenic-laden iron particles from the pressure filters. In 

light of the unsatisfactory treatment results, the regular sampling schedule was temporarily suspended and 

a series of special studies was carried out to determine the needs for process modifications to improve the 

filter performance. The results of the special studies are described in Section 4.5.2, including filter media 

run length, use of a higher iron dosage, use of a finer filter media size fraction, use of a C-05 iron/polymer 

blend, and use of other coagulant aids.
38

Table 4-9. Summary of Arsenic, Iron, and Manganese Analytical Results

Parameter

Sample 

Location Unit

Sample 

Count

Concentration Standard 

Minimum Maximum Average Deviation

As (total)

IN μg/L 11 59.8 96.7 84.0 12.4

AC μg/L 11 61.2 95.0 -

(a) -(a)

TA μg/L 8 8.4 22.4 -

(a) -(a)

TB μg/L 8 8.2 30.6 -

(a) -(a)

TT μg/L 3 16.8 28.3 -

(a) -(a)

As (soluble)

IN μg/L 4 59.7 85.5 76.8 11.6

AC μg/L 4 5.9 11.7 -

(a) -(a)

TA μg/L 1 4.4 4.4 -

(a) -(a)

TB μg/L 1 3.8 3.8 -

(a) -(a)

TT μg/L 3 4.8 7.2 -

(a) -(a)

As (particulate)

IN μg/L 4 0.1 10.3 4.2 5.0

AC μg/L 4 55.4 79.8 -

(a) -(a)

TA μg/L 1 4.0 4.0 -

(a) -(a)

TB μg/L 1 4.5 4.5 -

(a) -(a)

TT μg/L 3 9.6 23.5 -

(a) -(a)

As (III)

IN μg/L 3 0.1 1.4 0.7 0.7

AC μg/L 3 0.1 1.3 -

(a) -(a)

TT μg/L 3 0.1 1.6 -

(a) -(a)

As (V)

IN μg/L 3 59.0 85.4 74.5 13.7

AC μg/L 3 5.0 10.6 -

(a) -(a)

TT μg/L 3 3.2 6.0 -

(a) -(a)

Fe (total)

IN μg/L 11 <25 <25 <25 0

AC μg/L 11 1,153 2,502 -

(a) -(a)

TA μg/L 8 111 323 -

(a) -(a)

TB μg/L 8 96.1 561 -

(a) -(a)

TT μg/L 3 225 936 -

(a) -(a)

Fe (soluble)

IN μg/L 4 <25 <25 <25 0

AC μg/L 4 <25 41.5 -

(a) -(a)

TA μg/L 1 <25 <25 -

(a) -

(a)

TB μg/L 1 <25 <25 -

(a) -

(a)

TT μg/L 3 <25 <25 -

(a) -

(a)

Mn (total)

IN μg/L 10 <0.1 0.1 <0.1 0.0

AC μg/L 10 8 15 10 2.2

TA μg/L 7 0.5 6 3 1.5

TB μg/L 7 0.6 7 3 2.1

TT μg/L 3 3.2 9 5 3

Mn (soluble)

IN μg/L 3 <0.1 0.4 0.2 0.2

AC μg/L 3 3.1 6 4 1.8

TT μg/L 3 2.6 5 3 1

(a) Statistics not meaningful for data obtained under three separate sets of process conditions.
Table 4-10. Summary of Other Water Quality Parameter Results

Parameter

Sample 

Location Unit

Sample 

Count

Concentration Standard 

Minimum Maximum Average Deviation

Alkalinity 

(as CaCO3)

IN mg/L 10 266.0 297.0 284.5 10.4

AC mg/L 10 267.0 302.0 280.8 11.1

TA mg/L 7 265.0 295.0 281.0 9.6

TB mg/L 7 267.0 291.0 279.9 10.1

TT mg/L 3 262.0 288.0 278.0 14.0

Fluoride

IN mg/L 3 2.1 3.0 2.4 0.5

AC mg/L 3 2.1 3.1 2.5 0.6

TA mg/L 0 NS NS NS NS

TB mg/L 0 NS NS NS NS

TT mg/L 3 2.2 3.0 2.5 0.5

Sulfate

IN mg/L 3 20.0 22.0 21.0 1.0

AC mg/L 3 20.0 22.0 20.7 1.2

TA mg/L 0 NS NS NS NS

TB mg/L 0 NS NS NS NS

TT mg/L 3 20.0 22.0 21.0 1.0

Nitrate 

(as N)

IN mg/L 3 0.3 0.4 0.3 0.0

AC mg/L 3 0.3 0.4 0.4 0.1

TA mg/L 0 NS NS NS NS

TB mg/L 0 NS NS NS NS

TT mg/L 3 0.3 0.3 0.3 0.0

Total P 

(as P)

IN μg/L 9 17.1 53.7 32.8 12.3

AC μg/L 10 5.0 53.5 29.9 14.2

TA μg/L 7 5.0 15.6 -

(a) -(a)

TB μg/L 7 5.0 14.8 -

(a) -(a)

TT μg/L 3 11.0 18.6 -

(a) -(a)

Silica 

(as SiO2)

IN mg/L 10 46.8 50.8 48.5 1.3

AC mg/L 10 46.4 51.0 48.7 1.4

TA mg/L 7 45.6 49.2 47.4 1.4

TB mg/L 7 45.6 49.1 47.1 1.3

TT mg/L 3 47.8 50.3 49.2 1.3

Turbidity

IN NTU 9 0.1 1.1 0.5 0.3

AC NTU 10 0.6 3.3 -

(a) -(a)

TA NTU 7 0.3 1.5 -

(a) -(a)

TB NTU 7 0.3 0.9 -

(a) -(a)

TT NTU 3 0.4 0.9 0.7 0.3

Total 

Organic 

Carbon

IN mg/L 1 1.7 1.7 NA NA

AC mg/L 1 0.5 0.5 NA NA

TA mg/L 0 NS NS NS NS

TB mg/L 0 NS NS NS NS

TT mg/L 1 0.5 0.5 0.5 -

pH

IN S.U. 10 7.3 7.8 7.5 0.2

AC S.U. 10 7.1 7.9 7.5 0.3

TA S.U. 7 7.1 7.9 7.5 0.3

TB S.U. 7 7.1 8.0 7.5 0.4

TT S.U. 3 7.2 7.9 7.6 0.4

Temperature

IN °C 10 10.7 15.7 12.6 1.4

AC °C 10 10.5 15.7 12.3 1.6

TA °C 7 10.3 13.4 11.8 1.1

TB °C 7 10.4 13.3 11.8 1.1
Table 4-10. Summary of Other Water Quality Parameter Results (Continued)

40

Parameter

Sample 

Location Unit

Sample 

Count

Concentration Standard 

Minimum Maximum Average Deviation

Temperature 

(Cont) TT °C 3 11.1 15.8 13.2 2.4

Dissolved 

Oxygen

IN mg/L 9 2.1 3.3 2.6 0.4

AC mg/L 9 1.7 3.9 2.4 0.7

TA mg/L 6 1.6 2.9 2.4 0.4

TB mg/L 6 1.5 2.8 2.2 0.6

TT mg/L 3 2.0 3.1 2.4 0.6

ORP

IN mV 10 239.1 334.6 272.3 36.7

AC mV 10 280.7 506.9 341.9 80.1

TA mV 7 313.6 523.1 389.3 87.6

TB mV 7 312.7 548.1 400.1 96.3

TT mV 3 307.6 362.6 330.4 28.7

Free 

Chlorine 

(as Cl2)

AC mg/L 10 0.4 3.2 0.9 0.8

TA mg/L 7 0.4 3.1 1.0 1.0

TB mg/L 7 0.5 2.7 1.0 0.8

TT mg/L 3 0.6 0.8 0.7 0.1

Total 

Chlorine 

(as Cl2)

AC mg/L 10 0.4 3.2 0.9 0.8

TA mg/L 7 0.4 2.8 0.9 0.9

TB mg/L 7 0.5 3.1 1.0 1.0

TT mg/L 3 0.6 1.0 0.8 0.2

Total 

Hardness (as 

CaCO3)

IN mg/L 3 180.7 222.2 199.4 21.1

AC mg/L 3 183.7 247.6 211.2 32.9

TA mg/L 0 NS NS NS NS

TB mg/L 0 NS NS NS NS

TT mg/L 3 177.8 255.7 215.4 39.0

Ca Hardness 

(as CaCO3)

IN mg/L 3 128.4 167.4 146.8 19.6

AC mg/L 3 131.6 195.9 159.7 32.9

TA mg/L 0 NS NS NS NS

TB mg/L 0 NS NS NS NS

TT mg/L 3 128.5 204.1 163.4 38.1

Mg 

Hardness 

(as CaCO3)

IN mg/L 3 50.6 54.8 52.6 2.1

AC mg/L 3 51.0 52.1 51.6 0.6

TA mg/L 0 NS NS NS NS

TB mg/L 0 NS NS NS NS

TT mg/L 3 49.3 55.1 52.0 2.9

NA = not available; NS = not sampled

Figure 4-19 presents total iron concentrations measured across the treatment train. Iron was required 

because the facility decided to use the coagulation/filtration process rather than adsorptive media to 

remove arsenic. The addition of FeCl3 before the contact tanks resulted in total iron concentrations 

ranging from 1,153 μg/L to 2,502 μg/L and averaging 1,834 μg/L. Of the total iron, more than 98% was 

in the insoluble form based on the use of 0.45 μm disc filters during speciation sampling. Care must be 

taken in evaluating these data, however, since the presence of silica can cause the formation of dispersed 

colloidal material, which may penetrate through the 0.45 μm disc filters and be considered as particulates 

(Meng et al., 2000). Silica was present in the Three Forks source water at, on average, 48.5 mg/L (as 

SiO2). 
41

Arsenic Speciation at the Wellhead (IN)

0

10

20

30

40

50

60

70

80

90

100

11/29/2006 3/21/2007 4/18/2007

Date

As Concentration (μg/L)

As (particulate)

As (III)

As (V)

Arsenic Speciation after Chlorination (AC)

0

10

20

30

40

50

60

70

80

90

100

11/29/06 03/21/07 04/18/07

Date

As Concentration (μg/L)

As (particulate)

As (III)

As (V)

Arsenic Speciation after Total Combined Effluent (TT)

0

10

20

30

40

50

60

70

80

90

100

11/29/06 03/21/07 04/18/07

Date

As Concentration (μg/L)

As (particulate)

As (III)

As (V)

Figure 4-17. Arsenic Speciation Results
42

IN

AC

TA

TB

TT

0

10

20

30

40

50

60

70

80

90

100

10/10/0611/29/0601/18/0703/09/0704/28/0706/17/0708/06/07

Date

As Concentration (

μg/L)

As MCL = 10 

Figure 4-18. Total Arsenic Concentrations across Treatment Train

0

500

1000

1500

2000

2500

3000

10/10/0611/29/0601/18/0703/09/0704/28/0706/17/0708/06/0709/25/07

Date

Fe Concentration (μg/L)

IN

AC

TA

TB

TT

Fe SMCL = 300 μg/L

Figure 4-19. Total Iron Concentrations across Treatment Train
43

The removal of soluble arsenic onto iron solids also can be impacted by elevated pH and the presence of 

competing anions such as silica and phosphorus. pH values across the treatment train remained relatively 

constant at 7.5 (on average) (Table 4-10) and thus, should not have any major impact on arsenic removal. 

Silica begins to inhibit arsenic removal by ferric hydroxide at concentrations above 1 mg/L (Meng et al., 

2000). At 48.5 mg/L, silica might have caused lower than expected soluble arsenic removal in the contact 

tanks. Phosphorus at 32.8 μg/L (as P) also might compete with As(V) for available adsorption sites on 

iron solids.

4.5.1.2 Manganese. Manganese concentrations in raw water were <0.1 μg/L during all sampling 

events. Both total and soluble manganese (Mn) concentrations increased after the contact tanks,

averaging 10 and 4 μg/L, respectively. This is thought to be due to impurities in the chemicals used. 

Because the pressure filters removed only particulates, manganese levels after the pressure filters were 

lower on average at 5.0 μg/L. Studies have found that incomplete oxidation of Mn(II) occurs using free 

chlorine at pH values less than 8.5 (Knocke et al., 1987 and 1990; Condit and Chen, 2006; McCall et al., 

2007). 

4.5.1.3 Chlorine Residual. Total chlorine residuals remained relatively constant at 0.8 to 1.0 mg/L

(as Cl2) (on average) throughout the treatment train. Of these total chlorine levels, almost all existed as 

free chlorine, indicating the absence of ammonia in source water.

4.5.1.4 Other Water Quality Parameters. Alkalinity, fluoride, sulfate, nitrate, temperature, and 

hardness levels remained relatively constant across the treatment train and were not affected by the 

treatment process (Table 4-10). TOC, however, was removed with 1.7 mg/L in raw water, but only 0.5 

mg/L after the contact tanks and pressure filters. It is known that TOC can be removed via coagulation/ 

filtration with iron solids. 

4.5.2 Special Studies. Several special studies were carried out in an attempt to improve the

performance of the pressure filters. Key parameters investigated included buildup of Δp across the filters

over run time as well as arsenic and iron concentrations in the filter effluent. The studies included the use 

of a higher iron dosage, a finer filter media size fraction, and various coagulant aids/polymers. For the 

duration of the special study period, in order to achieve the 10-μg/L MCL, the City implemented a 

blending scenario with other wells to reduce the effect of high arsenic concentrations from Well 2. This 

involved reducing the operating schedule for Well 2 to three days per week (i.e., Monday, Wednesday 

and Friday). The blending resulted in arsenic concentrations between 4.4 and 8.6 μg/L prior to entering 

the distribution system.

4.5.2.1 Effect of Δp and Filter Run Time. A special study was carried out on December 20, 2006 to 

evaluate buildup of Δp across the filters over run time. With the addition of 1.8 mg/L of iron, Δp values 

across the pressure filters were 6 to 8 psi at 1 hr and 9 to 11 psi at 4 hr. This corresponds to a buildup rate 

of 1 psi/hr. Total arsenic concentrations in the filter effluent ranged from 8.1 to 8.3 μg/L at 1 hr and from 

12.3 to 15.5 μg/L at 4 hr. Coinciding with the increase in total arsenic concentration was an increase in 

total iron concentration (i.e., from <25 μg/L at 1 hr to as high as 176 μg/L at 4 hr). These results indicate

that the pressure filters can produce treatment effluent that meet the 10-μg/L MCL, but that their useful

run lengths can be very short, i.e., <4 hr. Because speciation was not performed during the study, it was 

not clear if the arsenic that broke through the filters was present in the soluble or particulate form. If a 

significant amount of arsenic indeed was present in the soluble form (like what was observed during the 

first three months of regular sampling [Section 4.5.1.1]), there would be value to add more iron to achieve

better soluble As(V) removal prior to pressure filtration. Conversely, the use of a higher iron dosage 

would inevitably produce more iron solids, which could further shorten useful run lengths, thus rendering 

the pressure filtration process virtually infeasible.
44

4.5.2.2 Effect of Higher Iron Dosage. For this special study (conducted on January 10, 2007) the 

FeCl3 dosage was increased from 1.8 to 2.2 mg/L (as Fe). The objective was to determine the effect of a 

higher iron dosage on total and soluble arsenic removal as well as particulate iron breakthrough. The

increase in iron dosage appears to have very little impact on the Δp buildup rate (data not shown), with a 

Δp buildup rate of 1 psi/hr observed for both filters. For Vessel A, arsenic levels increased from 7.6 and 

6.8 μg/L (at 1.4 hr) to 8.8 and 6.0 μg/L (at 2.4 hr) and to 11.9 and 6.4 μg/L (at 4.4 hr) for total and soluble 

arsenic, respectively. For Vessel B, arsenic levels increased from 10.8 and 6.2 μg/L (at 1.0 hr) to 11.8

and 6.2 μg/L (at 2.0 hr) and to 17.5 and 6.2 μg/L (at 4.0 hr) for total and soluble arsenic, respectively. 

The data illustrate that even at a higher iron dose, a significant amount of the total arsenic in the treated 

water was in the soluble form. As discussed in Section 4.5.1.1, silica and, to a lesser extent, phosphorus, 

might compete with arsenic for available adsorptive sites on iron solids, making removal of soluble 

arsenic less effective. Silica is also known to form complexes with arsenic in the colloidal size range,

which is small enough to pass through 0.45 μm filters and thus increase the apparent soluble arsenic 

concentration. As the filter run continued, particulate arsenic began to break through the filters, with 

concentrations increasing from 0.8 and 4.6 μg/L (at 1.4 hr) to 2.8 and 5.6 μg/L (at 2.4 hr) and to 5.5 and 

11.3 μg/L (at 4.4 hr) for Vessels A and B, respectively. The entirety of the iron breakthrough was in the 

particulate form, illustrating breakthrough of arsenic-laden iron solids.

0

2

4

6

8

10

12

14

16

18

20

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

Elapsed Time (hr)

Total As Concentration (ug/L)

0

50

100

150

200

250

300

350

400

Total Fe Concentration (ug/L)

Tank A (Total As)

Tank B (Total As)

Tank A (Total Fe)

Tank B (Total Fe)

Figure 4-20. Total Arsenic and Iron Levels with Use of a Higher Iron Dosage

While increasing the iron dosage from 1.8 to 2.2 mg/L (as Fe) (or increasing the Fe:As ratio from 22:1 to 

27:1) was not particularly effective in completely removing soluble arsenic from the contact tank and 

pressure filter effluent, it resulted in increased solids loading and increased particulate breakthrough from 

the pressure filters. A significant amount of particulate iron broke through the filters even within 1 hr of 
45

filter run time and greater than 10 μg/L of arsenic breakthrough occurred within 2 hr of filter run time, 

thus reducing the useful filter runtime under these operational conditions. As such, it was evident that 

increasing the iron dosage most likely would not produce better treatment results and that other treatment 

strategies needed to be developed to improve filter performance. 

4.5.2.3 Effect of Media Size Fraction. After consulting with the vendor, a decision was made to 

modify the filter beds by replacing a 6-in layer of the 40/60 mesh Macrolite® media with an equivalent 

amount of finer media, i.e., 70/80 mesh, in an attempt to achieve better particulate removal by the filters. 

After the media replacement on March 13, 2007, both vessels were backwashed to <5 NTU. After this, 

regular sampling as outlined in Table 3-3 resumed, with the treatment plant water samples collected in 

seven occasions (including one duplicate and two speciation sampling events) during March 21 and April 

25, 2007. Regular sampling was suspended again on April 25, 2007 due to poor filter performance. 

Analytical results as presented in Figures 4-17 through 4-20 and Appendix B indicated the following:

• With the addition of 1.8 mg/L of iron (as Fe) (on average), soluble arsenic concentrations 

were reduced from 80.4–85.5 at the influent sample tap to 10.7–11.7 μg/L after the contact 

tanks and to 5.8–7.2 μg/L after the pressure filters, with the soluble arsenic existing primarily 

as As[V] based on the March 21 and April 18, 2007, speciation sampling results. The 

speciation results also showed that particulate arsenic concentrations increased significantly 

to 78.7–79.8 μg/L after the contact tanks. These results were consistent with those obtained 

during the first three weeks of regular sampling (Section 4.5.1.1) and the above-mentioned

special studies (Sections 4.5.2.1 and 4.5.2.2). 

• After pressure filtration, total arsenic concentrations were reduced to 12.3–22.8 μg/L (or 16.1 

μg/L on average) (Appendix B), which were somewhat lower than those observed during the 

first three weeks of regular sampling, but very close to those collected at approximately 4 hr 

during the above-mentioned special studies. Of the 16.9-μg/L (on average) total arsenic 

measured during the two speciation sampling events, 6.5 μg/L existed as soluble arsenic and 

10.4 μg/L as particulate arsenic. These results again were similar to those collected during 

the above-mentioned special studies. Figure 4-21 displays the total arsenic breakthrough 

based on the filter run length for regular sampling events before (vessels with only 40/60 

mesh) and after (vessels with 40/60 mesh and 70/80 mesh) media replacement. There 

appears to be no benefit in total arsenic reduction resulting from the media replacement.

• Even after media replacement, >10-μg/L arsenic breakthrough was observed even less than 2 

hr. This is similar to what was found during the previous special study. Thus, the useful 

filter run length was not affected by the media replacement.

• 134 to 338 μg/L of total ion was measured in the filter effluent, with almost all existing in the 

particulate form. These results also were similar to those collected during the abovementioned special studies. 

The results obtained during this study period clearly suggest that the media bed modification failed to 

effectively remove arsenic-laden particles to below the MCL levels, which, in conjunction with the 

soluble arsenic, pushed the arsenic concentrations in the filter effluent well beyond the MCL level. 
46

0

5

10

15

20

25

30

35

0 2 4 6 8 10 12 14

Filter Run Length (hr)

Total As Cocnentration (ug/L)

TA with only 40/60 mesh

TA with 40/60 and 70/80 mesh

TB with only 40/60 mesh

TB with 40/60 and 70/80 mesh

Figure 4-21. Total Arsenic Breakthrough from Filters with 40/60 Mesh Media 

Only and 40/60 and 70/80 Mesh Amendment

4.5.2.4 Effect of Polymers/Coagulant Aids. The use of polymers/coagulant aids was then tested to 

determine their effects on particulate removal. A series of jar test was carried out by the vendor on June 

4, 2007 to determine the optimum chlorine and iron/polymer dose when applying an iron/organic polymer 

mixture named C-05. The results of the jar tests are presented in Table 4-11. As shown in the table, 

arsenic removal to below 10 μg/L might be achieved only with the use of 2.5 mg/L (as Fe) of the C-05 

blend. (Note that the impact of chlorine dosage on the treatment results appears to be minimal). At this 

dosage, the Fe:As ratio was 31:1, which is higher than the 22:1 and 27:1 ratios used for the abovementioned special studies. Not including the particulate arsenic that might break through the filters, the

use of the C-05 blend would produce a filter effluent containing 9 μg/L of arsenic, at best. 

Nonetheless, the use of the C-05 blend was implemented at the site on July 6, 2007 with a special run 

length study carried out on July 17, 2007. Figures 4-22 and 4-23 compare the results of this special study 

with those of an above-mentioned special study discussed in Section 4.5.2.2. By injecting 1.5 mg/L (as 

Cl2) of chlorine and 2.5 mg/L (as Fe) of C-05, total arsenic levels increased from 8.2–8.4 μg/L (at 2.7 hr) 

to 14.9–15.4 μg/L (at 5.3–5.7 hr) and to 22.9–24.3 μg/L (at 9.4–9.6 hr). Total iron concentrations 

increased from 96.1–111 μg/L (at 2.7 hr) to 332–358 μg/L (at 5.3–5.7 hr) to 547–614 μg/L (at 9.4–9.6 hr). 

The results collected at 2.7 and 5.3–5.7 hr were close to those of the previous special study collected at 

2.0–2.4 and 4.0–4.4 hr, respectively, indicating little or no improvement in filter performance with the use 

of the C-05 blend. Throughout the special study, soluble arsenic concentrations in the filter effluent were 

relatively constant at 3.8–4.5 μg/L and the total iron was in particulate form. These results further support 

the observation that minimum improvement, if any, was achieved with the use of the C-05 blend, 

although this special study does show somewhat increased soluble arsenic removal over the previous 

special study for iron addition.
47

Table 4-11. C-05 FeCl3/Polymer Blend Jar Test Results

Sample 

No.

Chlorine

Dosage

(mg/L 

as [Cl2])

C-05 

Blend

Dosage

(mg/L 

[as Fe])

Filtered

Concentration

Iron

(μg/L)

Arsenic

(μg/L)

0 0 0 <0.03 81

1 0.5 1.0 <0.03 34

2 0.5 1.5 <0.03 24

3 0.5 2.0 <0.03 14

4 0.5 2.5 <0.03 10

5 1.0 1.0 <0.03 35

6 1.0 1.5 <0.03 21

7 1.0 2.0 <0.03 18

8 1.0 2.5 <0.03 10

9 1.5 1.0 <0.03 33

10 1.5 1.5 <0.03 24

11 1.5 2.0 <0.03 13

12 1.5 2.5 <0.03 9

0

5

10

15

20

25

0 2 4 6 8 10 12

Run Time (hr)

Total As Concentration (ug/L)

0

200

400

600

800

1000

Total Fe Concentration (ug/L)

TA As w/ FeCl3 TA As w/ FeCl3/Polymer

TB As w/ FeCl3 TB As w/ FeCl3/Polymer

TA Fe w/ FeCl3 TA Fe w/ FeCl3/Polymer

TB Fe w/ FeCl3 TB Fe w/ FeCl3/Polymer

Figure 4-22. Total Arsenic and Iron Levels with Use of C-05 Blend
48

Figure 4-23 shows the effect of the C-05 blend on Δp buildup over filter run time. For Vessel A, Δp

levels increased from 13 to 23 psi after 6.9 hr. For Vessel B, Δp levels increased from 11 to 22 psi after 

6.7 hr. This corresponds to a Δp buildup rate of 1.4 to 1.6 psi/hr, which is higher than the 1.0 psi/hr 

buildup rate with the use of FeCl3 alone. The initial Δp levels after 2.7 hr of operation at 11 to 13 psi also 

were relatively elevated. It was noticed that the use of C-05 not only failed to produce lower levels of 

arsenic and iron in the filter effluent, but also promoted clogging of the filters. This was evidenced by 

several backwash alarms resulting from the inability to achieve the 20 NTU turbidity threshold within the 

maximum backwash time of 20 min. This resulted in a progressive increase in the turbidity threshold 

setting in the PLC from 20 to 25 and to 30 NTU in late July 2007 (Table 4-8). One disadvantage noted 

was that the coupled iron and polymer dosing with one chemical feed apparatus provided less flexibility 

in optimizing the polymer dose to avoid overdosing and clogging of the filters.

 

On August 1, 2007, FeCl3 addition was resumed pending investigation into other coagulation approaches.

0

5

10

15

20

25

0 2 4 6 8 10 12

Run Time (hr)

dP across Tank (psi)

TA w/ FeCl3

TB w/ FeCl3

TA w/ FeCl3/Polymer

TB w/ FeCl3/Polymer

Figure 4-23. Δp vs. Run Time with Use of C-05 Blend

A chemical supplier, Hawkins, was contacted and agreed to perform a series of jar tests to evaluate the 

effects of alum and several organic polymers on the filter performance. The results summarized in Table 

4-12 indicate that the use of alum or organic polymer(s) can achieve below the arsenic MCL-level of 

treatment results (i.e., 6.2 to 7.3), although any particulate breakthrough can easily push the effluent 

levels over the MCL. AquaHawk 427 at a 1 mg/L dosage was recommended by Hawkins based upon its

lower cost and the lowest soluble arsenic concentration in the jar test supernatant. The polyacrylamide 

polymers were not considered due to the need for a special make-up system and vendor’s concerns over 

the compatibility of the polymers with Macrolite® media. Alum was eliminated from further consideration 

due to the high dosage at 10 mg/L. In November 2007, the operator elected not to install a separate 

chemical feed system for polymer dosing and the alternate AquaHawk 427 polymer was not further tested 

in the treatment plant.
49

Table 4-12. Jar Test Results with Alum and Various Polymers

Polymer Ingredient (s)

Unit Cost

($/gal)

Polymer 

Dosage

(mg/L)

Filtered 

Concentration

Iron

(μg/L)

Arsenic

(μg/L)

AquaHawk 427 Polymer Blend [AL/PD/PY] $10.69 1.0 <25 6.2

AquaHawk 6527 PD $11.33 1.0 <25 6.7

AquaHawk 6547 PD $16.04 1.0 <25 6.7

Alum NA NA 10 <25 6.6

Aqua Hawk 9827 Long Chain Polymer NA 0.2 <25 6.8

Aqua Hawk 9827 Long Chain Polymer NA 0.5 <25 7.3

Aqua Hawk 9847 Long Chain Polymer NA 0.2 <25 7.3

Aqua Hawk 9847 Long Chain Polymer NA 0.5 <25 7.3

AL = Polyaluminum hydroxychloride

PD = Polydiallyldimethylammonium chloride

PY = Polyquaternary amine

4.5.3 Backwash Wastewater Sampling. Table 4-13 presents the analytical results from five 

monthly backwash wastewater sampling events. The backwash wastewater quality was similar for both 

vessels, indicating that the two vessels performed relatively consistently. For all events, the backwash 

wastewater had a pH of 7.2 to 7.5, with the majority of metals existing in the particulate form. The 

backwash wastewater samples collected from Events 1 to 4 were characteristic of normal operating 

conditions with iron addition. TDS ranged from 310 to 388 mg/L and averaged 350 mg/L; TSS ranged 

from 130 to 328 mg/L and averaged 235 mg/L. Concentrations of total arsenic, iron, and manganese 

ranged from 2,162 to 3,672 μg/L, 62,299 to 107,914 μg/L, and 202 to 411 μg/L, respectively. Assuming 

that these average results existed during the production of 1,167 gal/vessel of backwash wastewater, 

approximately 0.06 lb of arsenic, 1.6 lb of iron, and 0.006 lb of manganese were discharged from both 

filtration vessels during each backwash event. Of the amount discharged, some arsenic, iron, and 

manganese existed in the soluble form, including 10.5 to 50.4 μg/L of arsenic, 120 to 846 μg/L of iron, 

and 2.3 to 6.2 μg/L of manganese. The soluble arsenic and iron concentrations in the backwash 

wastewater were high when compared with those measured at most of the arsenic demonstration sites 

(Table 4-14). Because the presence of elevated silica (at 48.5 mg/L [as SiO2] on average in Well 2 water) 

could cause the formation of dispersed colloidal material, which might penetrate through the 0.45 μm disc 

filters and be considered as particulate (Meng et al., 2000), some of the “soluble” arsenic and iron might, 

in fact, exist as colloidal particles. 
50

Table 4-13. Backwash Wastewater Sampling Test Results

Sampling Event

BW1 BW2

Filter Vessel A Filter Vessel B

pHTDSTSSAs (total)

As (soluble)As (particulate)Fe (total)Fe (soluble)Mn (total)

Mn (soluble)pHTDSTSSAs (total)

As (soluble)As (particulate)Fe (total)Fe (soluble)Mn (total)

Mn (soluble)

No. Date S.U. mg/L mg/L μg/L μg/L μg/L μg/L μg/L μg/L μg/L S.U. mg/L mg/L μg/L μg/L μg/L μg/L μg/L μg/L μg/L

1 12/11/06 7.2 354 240 2,643 14.3 2,629 63,925 124 247 2.6 7.2 334 328 3,320 15.1 3,305 81,756 147 325 2.6

2 01/17/07(a) 7.4 310 205 3,200 13.4 3,187 93,131 176 327 2.7 7.4 334 130 2,561 21.5 2,540 75,082 370 259 3.3

3 02/21/07 7.4 350 206 2,426 29.7 2,396 69,396 513 225 4.6 7.4 348 192 2,162 50.4 2,112 62,299 846 202 6.2

4 03/20/07 7.4 388 266 3,474 10.5 3,464 96,403 120 349 2.3 7.4 384 312 3,672 22.1 3,650 107,914 391 411 3.7

5 04/25/07(b) 7.5 374 60 679 13.3 666 20,784 147 82.0 3.2 7.5 374 78 964 12.3 952 28,768 123 112 1.9

TDS = total dissolved solids; TSS = total suspended solids

(a) Backwash water recycling discontinued since 12/13/06.

(b) Lower concentrations due to shorter service run.

Note: Sampling generally conducted after 8 to 12 hr run time.
51

Table 4-14. Comparison of Soluble Arsenic and Iron Concentrations in Backwash Wastewater

Demonstration 

Location Arsenic Removal Technology

SiO2

Concentration

in Raw Water(a)

(mg/L)

Soluble Concentration in 

Backwash Wastewater(a)

As

(μg/L)

Fe

(μg/L)

Reno, NV

(Cumming et al., 2009)

GFH adsorptive media 72.6 (51.5–95.1) 15.7 (15.4–15.9) 29.7 (<25–34.0)

Three Forks, MT Coagulation/Macrolite® filtration with 

chlorine and iron addition

48.5 (46.8–50.8) 20.3 (10.5–50.4) 296 (120–846)

Bruni, TX

(Williams et al., 2007)

AD-33 adsorptive media 41.9 (40.6–43.9) NA NA

Arnaudville, LA Iron removal/Macrolite® filtration with 

chlorine (or KMnO4) and iron addition

41.0 (38.4–43.5) 18.0 (13.0–28.3) 44.2 (<25–81.2)

Lidgerwood, ND

(Condit et al., 2006)

Coagulation/sand filtration with 

iron/KMnO4/polymer addition

31.2 (29.0–34.2) 9.8 (7.5–11.9) < 25

Sabin, MN

(Condit et al., 2008)

Iron removal/Macrolite® filtration with 

chlorine addition

30.3 (28.5–32.5) 15.5 (6.1–27.6) 405 (67.3–827)

Climax, MN

(Condit et al., 2006)

Coagulation/Macrolite® filtration with 

chlorine and iron addition

28.7 (16.8–39.2) 12.4 (6.4–25.6) 119 (<25–771)

Sandusky, MI

(Valigore et al., 2008b)

Iron removal/AERALATER® Type II 

sand filtration with chlorine addition

12.0 (11.2–13.5) 3.2 (0.7–7.0) 86.1 (<25–196)

Pentwater, MI

(Valigore et al., 2008a)

Coagulation/Macrolite® filtration with 

chlorine and iron addition

11.2 (10.1–13.2) 8.8 (6.5–11.4) 157 (48.5–263)

(a) Data presented including average and range (in parentheses).

4.5.4 Distribution System Water Sampling. Table 4-15 summarizes the results of the 

distribution system sampling events. Before system startup, total arsenic concentrations in the baseline 

samples ranged from 4.0 to 11.6 μg/L and averaged 6.1 μg/L. Because Well 2 was used only for 

cemetery irrigation, the baseline sampling results reflect mainly the quality of Wells 5, 6, 8, and 9 water, 

which, as discussed in Section 4.1.1, did not contain elevated levels of arsenic. After system startup, total 

arsenic concentrations across the three distribution system sampling locations ranged from 0.9 to 14.9 

μg/L and averaged 6.8 μg/L, which is much lower than the 17.7 μg/L (on average) of the treated water 

samples collected during November 29, 2006, and July 17, 2007. This is due to the blending of the 

treated Well No. 2 water with source water from Wells No. 5, 6, 8, and 9 with low levels of arsenic. 

After the treatment system began operation, arsenic concentrations decreased at DS3 from an average 

baseline value of 5.3 to 4.2 μg/L. In contrast, arsenic concentrations increased slightly at both DS1 (from 

an average baseline value of 6.3 to 8.3 μg/L) and DS2 (from an average baseline value of 6.8 to 8.2 

μg/L). Samples at the DS3 location exhibited lower arsenic concentrations (about half of the average 

readings at DS1 and DS3), while exhibiting higher iron and manganese levels. 

Alkalinity, pH, and lead concentrations remained fairly consistent before and after system startup. 

Copper concentrations increased significantly from 45.6 to 176 μg/L (on average) at DS1 and from 44.2 

to 205 (on average) at DS3. At DS2, its concentrations decreased slightly from 153 to 142 μg/L. All 

concentrations were lower than the action level of 1.3 mg/L for copper.

4.6 System Cost

The system cost 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. Capital cost of the treatment system included cost for 

equipment, site engineering, and system installation, shakedown, and startup. O&M cost included cost 
52

Table 4-15. Distribution System Sampling Results

Sampling

Event

DS1 DS2 DS3(a)

Non-Residence Non-Residence LCR

Stagnation Time

pHAlkalinityAsFeMnPbCu

StagnationTime

pHAlkalinityAsFeMnPbCu

Stagnation Time

pHAlkalinityAsFeMnPbCu

No. Date hr S.U. mg/L μg/L μg/L μg/L μg/L μg/L hr S.U. mg/L μg/L μg/L μg/L μg/L μg/L hr S.U. mg/L μg/L μg/L μg/L μg/L μg/L

BL1 06/20/05(b) 12.8 7.7 308 9.1 33.6 42.0 0.4 54.3 39.8 7.6 308 11.6 74.3 60.7 4.4 284 8.0 7.7 308 7.0 114 88.2 0.2 16.7

BL2 07/19/05 8.5 7.5 299 5.3 106 59.3 0.5 53.3 8.5 7.4 299 4.6 62.4 85.6 0.8 110 7.0 7.6 308 4.5 256 197 0.5 49.9

BL3 08/16/05 9.5 7.7 308 5.2 <25 71.5 0.3 49.2 10.5 7.5 308 5.7 231 103 0.9 116 9.0 7.5 321 5.6 <25 145 0.6 67.7

BL4 09/20/05(c) 10.0 7.5 308 5.7 <25 56.1 0.3 25.6 11.0 7.5 295 5.4 90.0 99.1 0.2 102 6.2 7.6 304 4.0 86.4 147 0.3 42.4

1 12/13/06 9.0 7.4 311 8.9 <25 10.0 0.4 837 NA 7.3 287 11.7 43.8 20.9 0.7 141 9.0 7.3 280 10.8 36.0 18.1 <0.1 5.5

2 01/17/07(d) 11.0 7.5 304 6.9 <25 12.4 0.2 67.7 9.0 7.5 311 8.6 27.0 42.3 0.6 131 7.5 7.7 313 4.4 <25 52.5 0.5 482

3 02/21/07 9.5 7.6 328 10.8 28.0 28.0 0.5 60.6 9.5 7.6 336 13.0 79.8 56.0 0.9 218 7.5 7.7 353 13.0 77.4 82.2 1.9 531

4 03/20/07 11.0 7.6 332 7.0 27.1 31.4 0.3 225 9.0 7.5 322 5.3 <25 49.8 0.5 118 7.0 7.8 335 2.0 39.2 94.9 0.2 163

5 04/17/07 11.5 7.6 319 7.4 39.9 25.9 <0.1 29.9 9.5 7.6 319 6.7 50.7 58.0 <0.1 33.3 7.5 7.8 321 1.2 105 162 0.2 95.2

6 05/23/07 10.3 7.5 312 6.5 <25 18.5 0.2 433 11.5 7.5 310 5.8 <25 34.9 0.4 238 6.5 7.8 310 1.5 38.2 122 0.2 104

7 06/14/07(e) 10.3 7.7 320 8.0 <25 27.6 0.4 278 11.0 7.7 310 9.4 <25 28.4 0.2 45.2 6.5 7.7 310 3.3 <25 59.5 0.2 270

8 07/17/07 10.0 7.7 305 14.9 57.0 115 0.9 80.5 10.0 7.5 293 10.7 28.7 32.2 2.7 333 6.5 7.9 315 5.2 48.8 94.7 <0.1 628

9 09/17/07 12.5 7.6 301 12.8 <25 10.2 0.6 23.8 11.0 7.7 292 1.7 44.5 7.7 0.6 31.5 6.5 7.7 320 2.2 <25 77.6 0.4 20.8

10 10/17/07 11.3 7.5 294 7.2 27.2 17.6 0.2 63.1 11.0 7.6 308 8.7 62.4 55.6 0.5 132 6.5 7.6 300 0.9 <25 0.4 0.5 95.9

11 11/15/07 13.3 7.6 303 8.8 <25 15.5 0.1 81.9 11.0 7.6 287 8.6 <25 8.0 0.5 149 7.5 7.6 313 5.2 <25 18.3 0.2 74.0

12 12/11/07 13.3 7.6 294 7.2 <25 14.9 0.2 99.1 10.8 7.5 287 8.1 28.5 13.8 0.4 177 6.5 7.4 292 2.7 <25 13.2 0.2 44.7

13 01/15/08 13.8 7.5 281 1.7 41.4 22.2 0.6 9.4 10.0 7.8 308 8.9 168 67.8 0.4 93 6.0 7.8 302 2.4 143 142 0.3 154

(a) BL samples collected at a separate sampling location.

(b) DS1, DS2, and DS3 samples switched during sampling; correct results displayed. 

(c) DS3 sample collected on 09/19/05. 

(d) Increased distribution system blending scenario initiated since 01/01/07.

(e) Stagnation time, pH, and alkalinity measured on 06/19/07.

BL = baseline sampling; NA = data not available

Lead action level = 15 μg/L; copper action level = 1.3 mg/L

Alkalinity measured in mg/L (as CaCO3).
53

for chemicals, electricity, and labor. Cost associated with the building including the sump, sanitary sewer 

connections, and water system telemetry was not included in the capital cost because it was not included 

in the scope of this demonstration project and was funded separately by the City. 

4.6.1 Capital Cost. The capital investment for the FM-248-AS system was $305,447 (Table 4-16). 

The equipment cost was $168,142 (or 55% of the total capital investment), which included cost for a 

chlorine and an iron addition system, two contact tanks, two pressure vessels each loaded with 25 ft3 of 

Macrolite® media, instrumentation and controls, miscellaneous materials and supplies, labor, and system 

warranty. The system warranty cost covered the cost for repair and replacement of defective system 

components and installation workmanship for 12 months after system startup. 

Table 4-16. Capital Investment for FM-248-AS Treatment System

Description Cost

% of Capital 

Investment Cost

Equipment

Tanks, Valves, and Piping $79,349 –

Macrolite® Media (50 ft3) $10,939 –

Instrumentation and Controls $21,970 –

Air Scour System $5,373 –

Iron Addition System $6,454 –

Additional Sample Taps and Totalizers/Meters $1,717 –

Labor $35,311 –

Freight $7,029 –

Equipment Total $168,142 55%

Engineering

Labor $40,810 –

Subcontractor $12,625 –

Engineering Total $53,435 18%

Installation, Shakedown, and Startup 

Labor $14,000 –

Subcontractor $66,000 –

Travel $3,870 –

Installation, Shakedown, and Startup $83,870 27%

Total Capital Investment $305,447 100%

The site engineering cost covered the cost for preparing the required permit application submittal, 

including a process design report, a general arrangement drawing, P&IDs, electrical diagrams, 

interconnecting piping layouts, tank fill details, and a schematic of the PLC panel, and obtaining the 

required permit approval from MT DEQ. The engineering cost of $53,435 was 18% of the total capital 

investment.

The installation, shakedown, and startup cost covered the labor and materials required to unload, install, 

and test the system for proper operation. All installation activities were performed by the vendor’s 

subcontractor, and startup and shakedown activities were performed by the vendor with the operator’s 

assistance. The installation, startup, and shakedown cost of $83,870 was 27% of the total capital 

investment.
54

The total capital cost of $305,447 was normalized to $1,222/gpm ($0.85/gpd) of design capacity using the 

system’s rated capacity of 250 gpm (or 360,000 gpd). The total capital cost also was converted to an 

annualized cost of $28,831/yr using a capital recovery factor 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/week at the design flowrate of 

250 gpm to produce 131,400,000 gal/yr, the unit capital cost would be $0.22/1,000 gal. During the first 

year, the system produced approximately 27,234,000 gal of water, so the unit capital cost increased to 

$1.06/1,000 gal. 

A 371⁄3 ft × 331⁄3 ft building with a sidewall height of 16 ft was constructed by the City to house the 

treatment system (Section 4.4.2). Not included in the capital cost, the total cost of the building and 

supporting utilities, which were sized for two treatment systems, was approximately $120,000.

4.6.2 O&M Cost. O&M cost included chemical usage, electricity consumption, and labor for a 

combined unit cost of $0.18/1,000 gal (Table 4-17). No cost was incurred for repairs because the system 

was under warranty. Since chlorination was used only for disinfection purposes, the O&M cost only 

includes the incremental chemical cost for iron addition at $0.016/1,000 gal. Electrical power 

consumption was calculated based on the difference between the average monthly cost from electric bills 

before and after building construction and system startup. The difference in cost was approximately 

$209.50/month or $0.006/1,000 gal of water treated. Based on this time commitment and a labor rate of 

$19.63/hr, the labor cost was $0.16/1,000 gal of water treated.

Table 4-17. O&M Cost for FM-248-AS Treatment System

Category Value Remarks

Volume Processed (1,000 gal) 31,147 From 11/27/06 through 2/08/08

Chemical Usage

37–42% FeCl3 Unit Cost ($/lb) $0.34 Supplied in 600 lb drums including tax, 

surcharges, and drum deposit

FeCl3 Consumption (1b/1,000 gal) 0.048

Chemical Cost ($/1,000 gal) $0.016

Electricity Consumption

Electricity Cost ($/month) $209.50 Average incremental consumption after 

system startup; including building 

heating and lighting

Electricity Cost ($/1,000 gal) $0.006

Labor

Labor (hr/week) 4.7 30 min/day, 5 day/week

Labor Cost ($/1,000 gal) $0.16 Labor rate = $19.63/hr

Total O&M Cost ($/1,000 gal) $0.18 Including FeCl3 usage
55

5.0. REFERENCES

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.

Battelle. 2006. System Performance Evaluation Study Plan: U.S. EPA Arsenic Removal Technology 

Demonstration at City of Three Forks, MT. 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.L. Oxenham, and W.E. 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.

Condit, W.E. and A.S.C. Chen. 2006. Arsenic Removal from Drinking Water by Iron Removal, U.S. EPA 

Demonstration Project at Climax, MN, Final Performance Evaluation Report. EPA/600/R06/152. U.S. Environmental Protection Agency, National Risk Management Research 

Laboratory, Cincinnati, OH. 

Condit, W.E., A.S.C. Chen, and L. Wang. 2006. Arsenic Removal from Drinking Water by Process 

Modifications to Coagulation/Filtration, U.S. EPA Demonstration Project at Lidgerwood, ND,

Final Evaluation Report. EPA/600/R-06/159. U.S. Environmental Protection Agency, National 

Risk Management Research Laboratory, Cincinnati, OH. 

Condit, W.E. and A.S.C. Chen. 2008. Arsenic Removal from Drinking Water by Iron Removal, U.S. EPA 

Demonstration Project at Sabin, MN, Six-Month Evaluation Report. EPA/600/R-08/005. U.S. 

Environmental Protection Agency, National Risk Management Research Laboratory, Cincinnati, 

OH. 

Cumming, L.J., A.S.C. Chen, and L. Wang. 2009. Arsenic and Antimony Removal from Drinking Water 

by Adsorptive Media, U.S. EPA Demonstration Project at South Truckee Meadows General 

Improvement District (STMGID), NV, Final Performance Evaluation Report. EPA/600/R-09/016. 

U.S. Environmental Protection Agency, National Risk Management Research Laboratory, 

Cincinnati, OH.

Edwards, M., S. Patel, L. McNeill, H. Chen, M. Frey, A.D. Eaton, R.C. Antweiler, and H.E. Taylor.

1998. “Considerations in As Analysis and Speciation.” J. AWWA, 90(3): 103-113.

EPA. 2003. Minor Clarification of the National Primary Drinking Water Regulation for Arsenic. 

Federal Register, 40 CFR Part 141.

EPA. 2002. Lead and Copper Monitoring and Reporting Guidance for Public Water Systems. 

EPA/816/R-02/009. U.S. Environmental Protection Agency, Office of Water, Washington, D.C. 

EPA. 2001. National Primary Drinking Water Regulations: Arsenic and Clarifications to Compliance 

and New Source Contaminants Monitoring. Federal Register, 40 CFR Parts 9, 141, and 142. 

Iler, R.K. 1979. The Chemistry of Silica. Wiley-Interscience, New York.
56

Kinetico. 2006. The City of Three Forks, MT: Installation Manual; Suppliers Literature; and Operation 

and Maintenance Manual, Macrolite FM-248-AS Arsenic Removal System. Newbury, OH.

Knocke, W.R., R.C. Hoehn, and R.L. Sinsabaugh. 1987. “Using Alternative Oxidants to Remove 

Dissolved Manganese From Waters Laden With Organics.” J. AWWA, 79(3): 75-79.

Knocke, W.R., J.E. Van Benschoten, M. Kearney, A. Soborski, and D.A. Reckhow. 1990. “Alternative 

Oxidants for the Removal of Soluble Iron and Mn.” AWWA Research Foundation, Denver, CO.

Meng, X., S. Bang, and G.P. Korfiatis. 2000. “Effects of Silicate, Sulfate and Carbonate on Arsenic 

Removal by Ferric Chloride.” Water Research, 34(4): 1255-1261

McCall S.E., A.S.C. Chen, and L. Wang. 2007. Arsenic Removal from Drinking Water by Adsorptive 

Media, U.S. EPA Demonstration Project at Chateau Estates Mobile Home Park in Springfield, 

OH, Final Performance Evaluation Report. EPA/600/R-07/072. U.S. Environmental Protection 

Agency, National Risk Management Research Laboratory, Cincinnati, OH.

Robinson, R.B., Reed, G.D. and Frazier, B. 1992. “Iron and Manganese Sequestration Facilities Using 

Sodium Silicate” J. AWWA, 84(2): 77-82

Sorg, T.J. 2002. “Iron Treatment for Arsenic Removal Neglected.” Opflow, 28(11): 15.

Valigore, J.M., A.S.C. Chen, W.E. Condit, and L. Wang. 2008a. Arsenic Removal from Drinking Water 

by Coagulation/Filtration, U.S. EPA Demonstration Project at Village of Pentwater, MI, Final 

Performance Evaluation Report. EPA/600/R-08/011. U.S. Environmental Protection Agency, 

National Risk Management Research Laboratory, Cincinnati, OH. 

Valigore, J.M., A.S.C. Chen, W.E. Condit, and L. Wang. 2008b. Arsenic Removal from Drinking Water 

by Iron Removal, U.S. EPA Demonstration Project at City of Sandusky, MI, Final Performance 

Evaluation Report. EPA/600/R-08/007. U.S. Environmental Protection Agency, National Risk 

Management Research Laboratory, Cincinnati, OH.

Wang, L., A.S.C. Chen, and K.A. Fields. 2000. Arsenic Removal from Drinking Water by Ion Exchange 

and Activated Alumina Plants. EPA/600/R-00/088. U.S. Environmental Protection Agency, 

National Risk Management Research Laboratory, Cincinnati, OH. 

Wang, L., W.E. 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.

Williams, S., A.S.C. Chen, and L. Wang. 2007. Arsenic Removal from Drinking Water by Adsorptive 

Media, U.S. EPA Demonstration Project at Webb Consolidated Independent School District in 

Bruni, TX, Six-Month Evaluation Report. EPA/600/R-07/049. U.S. Environmental Protection 

Agency, National Risk Management Research Laboratory, Cincinnati, OH.
APPENDIX A

OPERATIONAL DATA
A1

US EPA Arsenic Demonstration Project at Three Forks, MT - Daily System Operation

Week 

No. Day Date Time

Run Time

12.5%

Cl2

Tank

Level

35% 

FeCl3

Tank 

Level

Pressure Filtration

Flow

rate

Totalizer to 

Distribution Backwash

Run Time Since 

Last BW

Totalizer Daily

Inlet TA TB Outlet

Daily 

Flow

Cal

Flow 

rate

Tank 

A

Tank 

B

Daily 

Volume

Vessel 

A

Vessel 

B

Vessel 

A

Vessel 

B

Vessel 

A

Vessel 

B

hr hr hr hr in in psig psig psig psig gpm kgal gpm No. No. kgal hr hr

1

Mon 11/27/06 5:50 NA NA 9.3 9.3 26.0 14.0 44 17 29 12 188 99 177 14 13 1.0 17.0 4.5

Tue 11/28/06 7:30 NA NA 12.3 12.3 31.0 33.0 45 26 21 12 185 141 191 15 13 1.0 8.2 11.9

Wed 11/29/06 7:30 NA NA 10.8 10.8 30.0 29.0 45 19 29 12 185 118 182 15 14 1.0 NA 13.5

Thu 11/30/06 6:30 NA NA 10.7 10.7 28.5 24.3 43 28 20 12 188 50 NA 16 14 1.3 4.3 17.8

Fri 12/01/06 7:00 NA NA 11.3 11.3 27.5 19.0 43 21 27 12 189 125 184 16 15 1.4 15.4 8.5

2

Mon 12/04/06 5:00 NA NA 10.3 10.3 26.3 14.3 45 23 21 12 186 116 188 17 15 1.0 9.9 18.9

Tue 12/05/06 4:30 NA NA 13.0 13.0 25.0 31.0 39 28 23 12 200 143 183 18 16 2.6 2.3 12.4

Wed 12/06/06 6:00 NA NA 13.3 13.3 23.3 25.3 41 21 29 12 195 174 218 18 17 1.1 15.5 5.7

Thu 12/07/06 5:30 NA NA 11.7 11.7 22.0 19.8 42 27 22 12 191 132 187 19 17 1.3 6.9 17.3

Fri 12/08/06 4:00 NA NA 12.2 12.2 20.5 14.0 42 26 22 12 192 136 186 20 18 2.6 3.5 8.9

3

Mon 12/11/06 5:30 NA NA 13.9 13.9 19.0 32.0 38 25 22 12 200 159 190 21 19 3.2 5.7 11.5

Tue 12/12/06 7:30 NA NA 12.5 12.5 17.3 27.3 39 25 25 12 198 148 197 22 20 2.3 8.1 9.2

Thu 12/14/06 6:00 NA NA 8.7 8.7 26.5 23.5 40 21 29 12 195 93 178 22 21 1.1 16.3 4.6

Fri 12/15/06 6:00 NA NA 11.8 11.8 25.3 19.0 41 24 24 12 193 135 190 23 21 0.9 10.4 16.3

4

Mon 12/18/06 5:00 NA NA 11.6 11.6 24.0 34.0 37 23 24 12 199 132 190 24 22 NA 7.5 8.0

Tue 12/19/06 6:00 NA NA 12.5 12.5 22.5 29.3 40 23 26 12 196 143 191 25 23 4.9 11.8 11.3

Wed 12/20/06 6:00 NA NA 11.4 11.4 21.3 25.0 35 25 27 12 207 124 182 26 24 2.4 2.7 2.2

Thu 12/21/06 6:00 NA NA 11.6 11.6 19.8 34.0 40 23 26 12 195 133 191 27 25 2.3 11.1 10.5

Fri 12/22/06 6:30 NA NA 12.0 12.0 18.5 29.8 35 25 27 12 205 131 181 28 26 2.3 2.5 2.1

5

Tue 12/26/06 5:00 NA NA 11.9 11.9 17.0 25.3 56 25 27 12 190 136 190 28 26 0.0 14.1 14.0

Wed 12/27/06 6:00 NA NA 12.9 12.9 15.5 20.3 41 23 25 12 191 150 193 29 27 2.1 12.7 12.3

Thu 12/28/06 6:00 NA NA 11.8 11.8 14.0 15.5 36 25 27 12 204 129 183 30 28 2.3 4.0 3.7

Fri 12/29/06 7:30 NA NA 11.8 11.8 12.5 10.5 43 22 25 12 189 133 188 30 28 0.0 15.8 15.4

6

Mon 01/01/07 6:00 NA NA 10.3 10.3 36.5 34.0 38 22 24 12 200 117 189 31 29 2.3 9.4 8.9

Wed 01/03/07 7:00 NA NA 8.9 8.9 35.3 31.0 37 22 24 12 200 102 191 32 30 2.3 8.3 7.9

Fri 01/05/07 7:00 NA NA 8.3 8.3 34.8 27.8 38 22 24 12 200 98 196 33 31 2.2 7.9 7.5

7

Mon 01/08/07 7:00 NA NA 9.9 9.9 33.8 24.3 37 22 24 12 200 100 169 34 32 NA 8.1 7.7

Wed 01/10/07 6:00 NA NA 8.2 8.2 32.8 22.5 38 22 24 12 196 109 222 35 33 2.6 9.0 8.5

Fri 01/12/07 6:00 NA NA 8.7 8.7 32.0 16.3 38 22 24 12 200 98 188 36 34 4.2 7.9 7.5

8

Mon 01/15/07 5:00 NA NA 9.2 9.2 31.0 35.0 38 22 24 12 200 107 194 37 35 2.3 8.7 8.3

Wed 01/17/07 7:00 NA NA 9.2 9.2 30.0 31.5 37 23 24 12 200 105 190 38 36 2.3 8.5 8.1

Fri 01/19/07 7:00 NA NA 10.0 10.0 29.0 27.8 36 22 25 12 200 114 190 39 37 2.2 7.5 6.9

9

Mon 01/22/07 4:30 NA NA 8.6 8.6 28.0 24.3 38 22 24 12 200 101 196 40 38 2.3 8.1 7.8

Wed 01/24/07 7:30 NA NA 9.1 9.1 27.0 20.5 38 22 24 12 198 130 239 41 39 2.4 8.7 8.2

Fri 01/26/07 6:30 NA NA 9.2 9.2 25.8 17.0 38 22 24 12 200 105 190 42 40 2.3 8.5 8.1

10

Mon 01/29/07 5:15 NA NA 9.4 9.4 24.8 12.5 38 22 24 12 200 109 193 43 41 2.3 8.8 8.4

Wed 01/31/07 7:15 NA NA 10.2 10.2 23.5 34.0 37 23 24 12 200 118 192 44 42 2.3 9.6 9.1

Fri 02/02/07 7:00 NA NA 9.9 9.9 22.3 30.3 38 23 24 12 200 115 193 45 43 2.3 9.4 8.9
US EPA Arsenic Demonstration Project at Three Forks, MT - Daily System Operation (Continued)

A2

Week 

No. Day Date Time

Run Time

12.5%

Cl2

Tank

Level

35% 

FeCl3

Tank 

Level

Pressure Filtration

Flow

rate

Totalizer to 

Distribution Backwash

Run Time Since 

Last BW

Totalizer Daily

Inlet TA TB Outlet

Daily 

Flow

Cal

Flow 

rate

Tank 

A

Tank 

B

Daily 

Volume

Vessel 

A

Vessel 

B

Vessel 

A

Vessel 

B

Vessel 

A

Vessel 

B

hr hr hr hr in in psig psig psig psig gpm kgal gpm No. No. kgal hr hr

11

Mon 02/05/07 5:45 NA NA 9.9 9.9 21.0 26.3 38 22 24 12 199 116 195 46 44 2.3 9.5 8.7

Wed 02/07/07 7:20 NA NA 9.8 9.8 19.8 22.5 37 22 24 12 200 108 184 47 49 5.5 9.0 7.5

Fri 02/09/07 6:15 NA NA 9.6 9.6 18.5 18.5 37 23 24 12 200 111 192 48 49 2.3 9.1 8.6

12 Mon 02/12/07 5:30 NA NA 10.3 10.3 17.3 14.0 39 21 24 12 196 121 195 49 50 2.3 9.9 9.0

Fri 02/16/07 6:30 NA NA 10.0 10.0 16.0 27.0 39 22 23 12 197 116 NA 50 51 2.3 9.5 8.8

13

Mon 02/19/07 6:15 8.1 8.0 8.1 8.0 15.0 23.5 37 22 24 12 201 99 NA 51 52 2.2 8.0 7.6

Wed 02/21/07 6:15 16.5 16.5 8.4 8.5 13.8 19.8 37 22 24 12 200 104 204 52 53 2.2 8.4 7.7

Fri 02/23/07 6:10 25.2 25.2 8.7 8.7 12.5 15.8 36 22 25 12 202 107 205 53 54 2.2 7.0 6.4

14

Mon 02/26/07 7:15 33.4 33.6 8.2 8.4 11.0 12.0 37 22 24 12 199 102 205 54 55 2.3 8.3 7.5

Wed 02/28/07 7:00 41.7 41.8 8.3 8.2 21.3 33.5 37 23 24 12 202 101 204 55 56 2.3 8.2 7.8

Fri 03/02/07 6:15 49.8 49.9 8.1 8.1 20.0 30.0 37 22 24 12 199 100 206 56 57 2.3 8.0 7.6

15

Mon 03/05/07 5:00 58.0 58.2 8.2 8.3 19.0 26.8 37 22 24 12 202 101 204 57 58 2.2 7.0 6.6

Wed 03/07/07 7:00 67.4 67.6 9.4 9.4 18.0 22.5 38 22 24 12 198 115 203 58 59 2.1 9.4 9.0

Fri 03/09/07 7:00 77.1 77.2 9.7 9.6 16.8 18.5 38 22 24 12 200 117 201 59 60 2.3 9.6 9.0

16

Mon 03/12/07 5:30 87.0 87.2 9.9 10.0 15.3 14.0 38 22 24 12 198 121 202 60 61 2.4 9.9 9.4

Wed 03/14/07 7:15 98.4 99.6 11.4 12.4 13.8 31.8 32 25 26 12 212 138 193 61 62 2.2 11.4 10.9

Fri 03/16/07 7:35 105.1 105.0 6.7 5.4 34.8 29.0 37 23 23 12 201 84 231 62 63 2.4 6.7 6.1

17

Mon 03/19/07 5:30 115.9 115.7 10.8 10.7 33.5 24.5 40 22 22 12 195 124 191 63 64 2.3 10.3 9.8

Tue 03/20/07 7:25 127.3 127.5 11.4 11.8 32.3 19.5 43 23 25 12 190 141 202 64 65 2.3 11.8 11.4

Wed 03/21/07 4:00 127.5 129.6 0.2 2.1 32.0 18.8 33 24 26 12 210 19 281 65 66 2.4 1.2 0.8

Fri 03/23/07 7:00 142.0 142.4 14.5 12.8 30.5 34.8 43 22 22 12 189 158 193 66 67 2.3 13.4 13.0

18

Mon 03/26/07 5:00 152.0 152.4 10.0 10.0 29.3 30.8 40 21 23 12 196 120 200 67 68 2.3 10.0 9.6

Wed 03/28/07 5:00 163.7 164.1 11.7 11.7 28.0 26.0 41 22 22 12 190 139 198 68 69 2.3 11.7 10.9

Fri 03/30/07 7:00 175.4 175.9 11.7 11.8 26.5 20.5 42 21 23 12 191 139 197 69 70 2.3 11.8 11.4

19

Mon 04/02/07 5:30 185.7 186.1 10.3 10.2 25.5 16.5 40 23 22 12 194 123 200 70 71 2.2 10.2 9.8

Wed 04/04/07 6:00 196.7 197.1 11.0 11.0 24.0 11.3 40 22 22 12 194 154 234 71 72 2.3 11.0 10.6

Fri 04/06/07 7:30 207.6 208.1 10.9 11.0 23.0 35.5 39 22 24 12 197 128 195 72 73 2.3 8.1 7.7

20

Mon 04/09/07 5:00 217.9 218.5 10.3 10.4 21.8 30.3 41 21 23 12 194 124 199 73 74 2.4 10.3 7.8

Wed 04/11/07 4:30 230.0 230.8 12.1 12.3 20.3 25.5 41 21 24 12 191 144 197 74 75 2.2 12.1 11.8

Fri 04/13/07 5:30 241.6 242.4 11.6 11.6 18.8 20.3 41 21 23 12 191 137 197 75 76 2.3 11.5 11.2

21

Mon 04/16/07 4:45 253.7 254.4 12.1 12.0 17.5 15.0 42 22 22 12 191 144 199 76 77 2.4 12.1 11.6

Wed 04/18/07 5:30 264.2 264.9 10.5 10.5 34.0 32.8 33 24 25 12 209 128 203 78 79 4.7 2.3 1.9

Fri 04/20/07 6:00 277.1 277.8 12.9 12.9 31.8 27.3 37 23 23 12 200 154 199 79 80 2.3 7.1 6.7

22

Mon 04/23/07 5:00 289.2 290.5 12.1 12.7 30.5 21.8 35 23 25 12 205 154 207 81 82 4.8 3.5 3.2

Tue 04/24/07 7:30 303.1 302.9 13.9 12.4 28.8 16.0 33 22 24 12 205 152 192 83 84 4.9 4.2 3.7

Wed 04/25/07 7:30 307.9 305.8 4.8 2.9 27.8 12.8 35 25 26 12 204 83 361 84 85 2.2 1.9 1.6

Thu 04/26/07 11:00 317.6 318.6 9.7 12.8 26.5 34.0 34 27 29 12 207 107 158 86 87 4.8 0.4 0.0

Fri 04/27/07 11:00 323.7 324.7 6.1 6.1 25.8 31.5 42 22 22 12 196 72 196 86 87 0.0 6.5 6.1

Sat 04/28/07 10:00 329.8 330.8 6.1 6.1 25.0 28.8 37 23 23 12 198 74 202 87 88 2.3 4.5 4.1

Sun 04/29/07 11:00 337.1 338.1 7.3 7.3 23.8 25.8 37 22 22 12 201 87 199 88 89 2.4 3.7 3.3
US EPA Arsenic Demonstration Project at Three Forks, MT - Daily System Operation (Continued)

A3

Week 

No. Day Date Time

Run Time

12.5%

Cl2

Tank

Level

35% 

FeCl3

Tank 

Level

Pressure Filtration

Flow

rate

Totalizer to 

Distribution Backwash

Run Time Since 

Last BW

Totalizer Daily

Inlet TA TB Outlet

Daily 

Flow

Cal

Flow 

rate

Tank 

A

Tank 

B

Daily 

Volume

Vessel 

A

Vessel 

B

Vessel 

A

Vessel 

B

Vessel 

A

Vessel 

B

hr hr hr hr in in psig psig psig psig gpm kgal gpm No. No. kgal hr hr

23

Mon 04/30/07 10:30 344.7 345.7 7.6 7.6 22.5 22.3 37 23 24 12 201 92 201 89 90 2.3 3.2 2.8

Tue 05/01/07 10:45 352.4 353.9 7.7 8.2 21.5 18.8 36 22 22 12 203 99 207 90 91 2.3 3.3 2.9

Wed 05/02/07 11:00 360.5 361.8 8.1 7.9 20.3 15.0 37 23 22 12 204 95 198 91 92 2.4 3.1 2.7

Thu 05/03/07 12:00 367.0 368.0 6.5 6.2 19.3 36.3 33 25 26 12 208 79 208 92 93 2.3 2.0 1.0

Fri 05/04/07 11:30 374.0 375.0 7.0 7.0 18.0 33.5 34 27 28 12 209 84 200 93 94 2.4 1.0 0.0

Sat 05/05/07 12:15 379.5 380.5 5.5 5.5 17.3 31.5 36 24 25 12 200 61 184 93 94 0.0 5.6 5.2

Sun 05/06/07 11:25 385.6 386.6 6.1 6.1 16.5 29.0 35 24 26 12 203 74 203 94 95 2.4 3.6 3.2

24

Mon 05/07/07 10:30 395.8 396.8 10.2 10.2 14.8 24.5 37 24 26 12 201 122 199 95 96 1.9 5.7 5.3

Tue 05/08/07 6:15 404.9 405.9 9.1 9.1 33.8 34.0 37 25 25 12 200 110 201 96 97 2.9 6.7 6.3

Wed 05/09/07 7:30 413.8 414.8 8.9 8.9 32.8 30.5 38 23 25 12 197 106 198 97 98 2.3 7.5 7.1

Thu 05/10/07 8:00 424.1 425.1 10.3 10.3 31.3 26.0 33 25 26 12 208 126 204 99 100 4.9 1.6 1.2

Fri 05/11/07 8:00 430.3 431.4 6.2 6.3 30.5 23.5 37 24 24 12 196 73 195 99 100 0.0 7.8 7.5

Sat 05/12/07 8:20 436.0 437.5 5.7 6.1 29.5 34.3 37 24 26 12 202 74 208 100 101 2.3 5.7 5.3

Sun 05/13/07 7:15 445.6 446.7 9.6 9.2 28.3 30.5 37 23 25 12 198 111 198 101 102 2.2 6.9 6.5

25

Mon 05/14/07 7:45 457.1 458.2 11.5 11.5 26.8 25.5 34 25 26 12 205 139 202 103 104 4.6 2.2 1.8

Tue 05/15/07 8:00 466.6 467.7 9.5 9.5 34.5 32.0 35 25 26 12 204 138 241 104 105 2.4 3.6 3.2

Wed 05/16/07 7:30 472.2 473.3 5.6 5.6 33.8 29.8 33 25 26 12 209 68 203 105 106 2.4 1.1 0.7

Thu 05/17/07 8:00 484.5 485.6 12.3 12.3 32.0 24.5 37 24 25 12 200 147 199 106 107 2.4 5.3 4.9

Fri 05/18/07 8:00 491.3 492.3 6.8 6.7 31.0 21.5 35 24 26 12 205 81 201 107 108 2.4 4.0 3.5

Sat 05/19/07 8:00 501.8 502.8 10.5 10.5 29.8 33.0 36 24 25 12 198 125 198 108 109 2.4 6.4 5.9

Sun 05/20/07 8:00 512.7 513.7 10.9 10.9 28.3 29.0 32 25 26 12 208 124 189 110 111 4.7 0.5 0.1

26

Mon 05/21/07 8:00 522.2 523.3 9.5 9.6 27.5 32.5 34 25 26 12 205 121 211 111 112 2.4 2.5 2.1

Thu 05/24/07 7:00 531.2 532.2 9.0 8.9 26.3 29.0 35 25 26 12 204 108 200 112 113 2.4 3.4 2.9

Sat 05/26/07 5:00 541.3 542.4 10.1 10.2 24.8 24.5 37 24 25 12 202 121 199 113 114 2.4 5.4 5.0

Sun 05/27/07 NA 545.3 546.4 4.0 4.0 24.3 22.8 33 25 26 12 206 50 207 114 115 2.3 1.3 0.9

27

Wed 05/30/07 7:00 554.4 555.5 9.1 9.1 23.0 18.5 35 25 26 12 208 110 201 115 116 2.4 2.4 2.0

Thu 05/31/07 7:00 564.4 565.6 10.0 10.1 21.0 33.0 36 25 26 12 201 122 202 116 117 2.4 4.4 3.9

Fri 06/01/07 7:30 574.3 575.3 9.9 9.7 19.8 29.0 36 24 25 12 200 116 197 117 118 2.2 6.0 5.5

Sat 06/02/07 9:00 579.7 580.8 5.4 5.5 18.8 26.5 35 25 26 12 206 67 204 118 119 2.4 3.3 2.9

Sun 06/03/07 7:30 589.4 590.5 9.7 9.7 17.3 22.5 36 24 26 12 203 117 201 119 120 2.3 4.9 4.5

28

Mon 06/04/07 5:00 599.5 600.6 10.1 10.1 15.8 33.8 38 24 25 12 200 121 199 120 121 2.4 6.9 6.5

Tue 06/05/07 6:00 610.0 611.2 10.5 10.6 14.0 29.3 33 26 27 12 209 129 203 122 123 4.7 1.3 0.9

Sat 06/09/07 8:30 620.9 622.0 10.9 10.8 35.3 25.0 36 25 26 12 206 130 200 123 124 2.4 4.0 3.6

Sun 06/10/07 8:00 632.4 633.4 11.5 11.4 34.0 20.0 38 24 26 12 200 138 200 124 125 2.2 7.4 6.9

29

Mon 06/11/07 9:00 640.4 641.4 8.0 8.0 32.8 16.3 36 24 25 12 206 97 202 125 126 2.4 7.3 6.8

Tue 06/12/07 7:00 650.1 651.1 9.7 9.7 31.5 33.3 33 26 27 12 212 120 206 127 128 4.2 0.8 0.3

Wed 06/13/07 7:30 661.2 662.5 11.1 11.4 30.0 28.8 35 25 26 12 206 137 204 128 129 2.9 4.1 3.6

Thu 06/14/07 8:00 672.6 673.6 11.4 11.1 28.3 24.0 39 24 26 12 200 134 199 129 130 2.3 7.1 6.6

Fri 06/15/07 6:45 678.8 678.8 6.2 5.2 27.5 21.0 37 25 26 12 205 78 228 130 131 2.3 5.2 4.8

Sat 06/16/07 8:00 684.4 685.5 5.6 6.7 26.5 32.0 35 25 27 12 211 69 186 131 132 2.4 2.7 2.3

Sun 06/17/07 9:00 696.4 697.2 12.0 11.7 24.8 27.8 38 24 26 12 204 142 200 132 133 2.4 6.7 5.9
US EPA Arsenic Demonstration Project at Three Forks, MT - Daily System Operation (Continued)

A4

Week 

No. Day Date Time

Run Time

12.5%

Cl2

Tank

Level

35% 

FeCl3

Tank 

Level

Pressure Filtration

Flow

rate

Totalizer to 

Distribution Backwash

Run Time Since 

Last BW

Totalizer Daily

Inlet TA TB Outlet

Daily 

Flow

Cal

Flow 

rate

Tank 

A

Tank 

B

Daily 

Volume

Vessel 

A

Vessel 

B

Vessel 

A

Vessel 

B

Vessel 

A

Vessel 

B

hr hr hr hr in in psig psig psig psig gpm kgal gpm No. No. kgal hr hr

30

Mon 06/18/07 7:00 701.7 702.8 5.3 5.6 24.0 24.8 36 26 26 12 207 70 214 133 134 2.3 3.8 3.4

Tue 06/19/07 7:00 711.7 712.8 10.0 10.0 25.8 33.5 37 25 25 12 205 126 211 134 135 2.3 5.7 5.3

Wed 06/20/07 5:30 725.4 724.5 13.7 11.7 24.0 27.0 34 26 27 12 214 138 182 136 137 4.6 1.2 0.8

Thu 06/21/07 6:45 736.2 737.3 10.8 12.8 22.0 23.5 39 24 26 12 201 198 280 137 138 2.4 5.9 5.5

Fri 06/22/07 4:00 747.6 748.7 11.4 11.4 20.3 18.3 34 26 27 12 215 120 175 139 140 4.7 1.1 0.7

Sat 06/23/07 4:30 760.3 761.4 12.7 12.7 18.3 12.3 37 25 27 12 205 154 201 140 141 2.2 5.7 5.3

Sun 06/24/07 6:00 771.4 772.5 11.1 11.1 37.5 32.8 34 26 27 12 216 138 207 142 143 4.6 0.6 0.2

31

Mon 06/25/07 4:30 784.7 786.0 13.3 13.5 35.8 27.3 37 25 26 12 205 165 205 143 144 2.4 6.0 5.7

Tue 06/26/07 4:00 798.1 799.2 13.4 13.2 34.0 21.8 36 26 27 12 210 163 204 145 146 4.9 3.0 2.7

Wed 06/27/07 4:00 809.0 810.0 10.9 10.8 32.5 17.0 37 25 26 12 205 132 202 146 147 2.3 5.8 5.4

Thu 06/28/07 4:00 821.3 822.4 12.3 12.4 30.8 33.5 35 26 27 12 212 152 206 148 149 4.7 2.0 1.6

Fri 06/29/07 4:00 834.4 835.5 13.1 13.1 28.8 28.5 38 24 26 12 200 159 202 149 150 2.4 7.0 6.6

Sat 06/30/07 4:00 849.3 850.1 14.9 14.6 26.5 22.0 37 25 26 12 205 182 205 151 152 4.7 5.7 5.3

Sun 07/01/07 2:30 863.5 864.2 14.2 14.1 24.5 32.3 36 25 26 12 207 173 203 153 154 4.6 3.7 3.3

32

Mon 07/02/07 2:30 877.8 878.9 14.3 14.7 22.5 26.5 34 26 27 12 211 173 199 155 156 4.8 1.8 1.4

Tue 07/03/07 2:30 896.5 897.7 18.7 18.8 19.5 29.8 37 26 27 12 205 228 203 157 158 4.7 4.3 3.9

Wed 07/04/07 2:30 913.9 915.0 17.4 17.3 16.8 22.5 37 25 26 12 206 210 202 159 160 4.5 5.5 5.1

Thu 07/05/07 2:30 928.7 929.8 14.8 14.8 14.3 16.0 36 26 26 12 207 180 203 161 162 4.7 4.1 3.7

Fri 07/06/07 2:30 948.1 949.2 19.4 19.4 33.0 13.3 39 25 26 12 200 234 201 163 164 4.6 7.3 7.0

Sat 07/07/07 2:30 971.0 972.1 22.9 22.9 29.8 28.8 41 25 26 12 198 275 200 166 167 7.1 5.9 5.5

Sun 07/08/07 4:50 993.3 994.3 22.3 22.2 26.8 19.0 39 26 27 12 204 268 200 169 170 7.0 3.9 3.5

33

Tue 07/10/07 2:30 994.0 995.0 0.7 0.7 26.5 37.3 38 25 27 12 203 8 193 169 170 0.0 4.6 4.1

Wed 07/11/07 2:30 1010.4 1011.5 16.4 16.5 24.0 30.5 39 24 26 12 203 221 224 171 172 4.7 4.8 4.4

Thu 07/12/07 2:30 1027.2 1028.3 16.8 16.8 21.5 23.5 39 24 26 12 201 201 199 173 174 4.7 5.4 5.0

Fri 07/13/07 6:00 1032.7 1033.8 5.5 5.5 20.8 21.0 38 26 27 12 205 68 205 174 175 2.4 2.8 2.4

34

Mon 07/16/07 8:30 1043.6 1044.9 10.9 11.1 19.0 16.0 39 25 27 12 199 132 200 175 176 2.2 5.8 5.4

Tue 07/17/07 4:00 1053.5 1054.7 9.9 9.8 17.5 33.5 42 23 26 12 195 116 196 176 177 2.2 7.5 7.1

Wed 07/18/07 8:30 1063.0 1064.1 9.5 9.4 16.0 29.8 34 28 29 12 213 113 200 178 179 4.7 0.4 0.0

Thu 07/19/07 7:30 1068.8 1069.8 5.8 5.7 15.3 27.5 42 25 26 12 195 68 197 178 179 0.0 6.2 5.7

Fri 07/20/07 6:00 1074.6 1075.5 5.8 5.7 14.5 24.5 39 26 27 12 203 70 202 179 180 2.4 3.9 3.5

35

Mon 07/23/07 7:30 1081.7 1082.6 7.1 7.1 13.5 21.5 37 26 27 12 205 86 201 180 181 2.4 2.9 2.5

Tue 07/24/07 6:00 1088.2 1089.1 6.5 6.5 34.8 34.5 35 27 28 12 212 78 199 181 182 2.2 1.3 0.9

Wed 07/25/07 7:30 1098.4 1099.1 10.2 10.0 33.3 30.0 38 26 27 12 204 127 210 183 184 6.2 3.8 3.3

Thu 07/26/07 6:30 1104.7 1105.4 6.3 6.3 32.5 27.3 36 28 28 12 206 76 201 184 185 2.3 2.0 1.5

Fri 07/27/07 6:00 1116.5 1116.2 11.8 10.8 31.3 22.3 39 26 27 12 203 129 190 185 186 2.3 4.7 4.2

36

Mon 07/30/07 9:30 1122.8 1123.6 6.3 7.4 30.5 19.0 31 22 23 12 168.7 89 217 186 187 4.1 3.9 3.4

Tue 07/31/07 8:00 1126.6 1128.5 3.8 4.9 29.8 17.3 37 25 27 12 205 48 184 187 188 2.3 3.6 3.2

Wed 08/01/07 4:30 1135.6 1136.1 9.0 7.6 28.8 18.8 37 26 27 12 205 113 227 189 190 5.3 2.4 2.1

Thu 08/02/07 9:00 1137.8 1138.8 2.2 2.7 28.5 17.5 36 27 27 12 206 27 186 190 191 1.7 2.0 1.6

Fri 08/03/07 6:00 1145.0 1146.0 7.2 7.2 27.5 33.5 36 25 27 12 203 89 206 191 192 2.4 4.2 3.8
US EPA Arsenic Demonstration Project at Three Forks, MT - Daily System Operation (Continued)

A5

Week 

No. Day Date Time

Run Time

12.5%

Cl2

Tank

Level

35% 

FeCl3

Tank 

Level

Pressure Filtration

Flow

rate

Totalizer to 

Distribution Backwash

Run Time Since 

Last BW

Totalizer Daily

Inlet TA TB Outlet

Daily 

Flow

Cal

Flow 

rate

Tank 

A

Tank 

B

Daily 

Volume

Vessel 

A

Vessel 

B

Vessel 

A

Vessel 

B

Vessel 

A

Vessel 

B

hr hr hr hr in in psig psig psig psig gpm kgal gpm No. No. kgal hr hr

37

Mon 08/06/07 7:00 1152.0 1152.9 7.0 6.9 26.8 30.5 35 27 28 12 210 99 237 193 194 4.7 1.0 0.5

Tue 08/07/07 6:00 1163.3 1164.3 11.3 11.4 25.5 26.0 37 26 27 12 203 126 185 194 195 2.2 4.1 3.8

Wed 08/08/07 6:30 1176.4 1177.4 13.1 13.1 23.8 22.5 35 27 28 12 212 159 202 196 197 4.8 1.1 0.7

Thu 08/09/07 6:00 1189.8 1190.8 13.4 13.4 22.0 31.3 39 26 26 12 201 162 202 197 198 2.3 6.4 6.2

Fri 08/10/07 5:30 1201.7 1202.7 11.9 11.9 20.5 26.5 36 27 27 12 210 147 206 199 200 5.3 2.2 1.7

Sat 08/11/07 8:00 1213.6 1214.5 11.9 11.8 18.8 21.5 39 26 26 12 204 141 199 200 201 2.3 5.9 5.4

Sun 08/12/07 6:30 1223.4 1224.3 9.8 9.8 17.5 34.0 40 26 26 12 199 118 201 201 202 2.4 7.6 7.1

38

Mon 08/13/07 6:00 1236.3 1236.2 12.9 11.9 16.0 29.5 36 26 27 12 205 146 196 203 204 4.5 3.3 2.8

Tue 08/14/07 4:00 1247.3 1248.3 11.0 12.1 14.5 24.5 40 25 27 12 199 146 211 204 205 2.2 7.3 6.9

Wed 08/15/07 6:00 1259.5 1260.5 12.2 12.2 12.5 33.0 36 27 27 12 205 149 203 206 207 4.6 3.3 2.9

Thu 08/16/07 4:30 1274.3 1272.3 14.8 11.8 11.0 28.5 39 25 26 12 199 165 207 207 208 2.3 7.0 6.6

Fri 08/17/07 5:30 1285.6 1284.6 11.3 12.3 9.0 23.5 36 26 27 12 205 151 213 209 210 4.7 3.1 2.7

Sat 08/18/07 7:30 1294.6 1295.6 9.0 11.0 30.0 32.5 39 26 27 12 202 132 221 210 211 2.3 6.0 5.6

Sun 08/19/07 11:30 1303.2 1304.4 8.6 8.8 29.0 29.3 39 25 27 12 199 107 204 211 212 3.1 6.5 6.1

39

Mon 08/20/07 5:45 1306.3 1307.3 3.1 2.9 28.5 27.8 35 27 28 12 210 40 219 212 213 4.6 1.5 0.9

Tue 08/21/07 6:00 1317.0 1318.1 10.7 10.8 27.3 34.0 36 26 27 12 207 137 213 215 216 7.2 2.5 2.2

Wed 08/22/07 6:00 1327.6 1325.7 10.6 7.6 26.0 30.0 35 26 28 12 210 131 240 217 218 4.8 1.0 0.6

Thu 08/23/07 6:00 1339.4 1340.6 11.8 14.9 24.5 25.0 34 27 28 12 210 147 183 219 220 4.8 0.7 0.3

Fri 08/24/07 7:00 1351.9 1353.0 12.5 12.4 22.8 19.5 34 27 28 12 209 153 205 221 222 4.7 0.9 0.5

Sat 08/25/07 8:00 1361.7 1362.1 9.8 9.1 21.5 15.5 37 26 27 12 205 118 208 222 223 2.2 4.6 4.2

40 Tue 08/28/07 13:00 1369.8 1370.8 8.1 8.7 20.5 33.5 35 26 28 12 205 98 194 224 225 4.6 0.5 0.0

Wed 08/29/07 6:00 1374.4 1375.3 4.6 4.5 19.8 31.8 37 26 26 12 203 52 192 224 225 0.0 5.1 4.5

41

Tue 09/04/07 5:30 1384.8 1385.7 10.4 10.4 18.5 27.5 36 26 27 12 205 129 207 226 227 4.7 3.3 2.7

Wed 09/05/07 7:00 1393.7 1394.7 8.9 9.0 17.3 23.8 35 26 27 12 205 112 209 228 229 4.7 2.8 2.4

Thu 09/06/07 6:00 1401.6 1402.5 7.9 7.8 16.3 20.5 37 26 26 12 203 96 204 229 230 2.4 4.6 4.2

Fri 09/07/07 6:00 1408.0 1409.0 6.4 6.5 15.3 17.5 37 26 26 12 202 79 204 230 231 2.3 4.9 4.5

42

Mon 09/10/07 5:00 1414.0 1415.0 6.0 6.0 14.3 14.5 38 25 27 12 202 75 209 231 232 2.4 4.8 4.5

Tue 09/11/07 7:00 1421.8 1422.9 7.8 7.9 34.8 34.5 40 25 27 12 200 96 203 232 233 2.4 7.7 7.3

Wed 09/12/07 7:00 1428.0 1429.1 6.2 6.2 34.0 31.8 38 26 26 12 204 77 206 233 234 2.2 5.8 5.4

Thu 09/13/07 9:00 1434.8 1435.9 6.8 6.8 33.0 29.0 37 26 27 12 205 83 204 234 236 2.4 4.5 4.1

Fri 09/14/07 6:00 1441.9 1442.8 7.1 6.9 32.3 26.0 37 26 27 12 207 87 208 235 236 2.3 3.5 2.9

Sat 09/15/07 7:30 1449.2 1450.2 7.3 7.4 31.5 22.8 36 26 27 12 207 91 205 236 237 2.3 2.7 2.2

Sun 09/16/07 6:30 1458.2 1459.3 9.0 9.1 30.3 19.0 37 26 27 12 207 110 202 237 238 2.4 3.6 3.2

43

Mon 09/17/07 6:00 1469.5 1470.6 11.3 11.3 29.0 13.8 39 25 27 12 201 136 200 238 239 2.3 6.8 6.4

Tue 09/18/07 7:00 1477.4 1478.5 7.9 7.9 28.0 35.3 40 25 27 12 200 99 208 239 240 2.4 6.6 6.2

Wed 09/19/07 7:00 1485.4 1480.5 8.0 2.0 27.3 32.8 38 26 27 12 204 78 261 240 241 2.3 4.9 4.4

Thu 09/20/07 6:30 1489.9 1491.1 4.5 10.6 26.5 30.0 36 26 28 12 209 77 171 241 242 2.3 3.0 2.6

Fri 09/21/07 7:00 1496.1 1497.2 6.2 6.1 25.5 27.5 35 27 28 12 211 75 204 242 243 2.4 1.0 0.6

Sat 09/22/07 7:00 1501.5 1502.6 5.4 5.4 25.0 35.5 39 26 26 12 202 64 198 242 243 0.0 6.4 5.9

Sun 09/23/07 12:00 1509.4 1511.0 7.9 8.4 24.0 32.5 39 25 27 12 198 103 210 243 244 2.3 6.7 6.3
US EPA Arsenic Demonstration Project at Three Forks, MT - Daily System Operation (Continued)

A6

Week 

No. Day Date Time

Run Time

12.5%

Cl2

Tank

Level

35% 

FeCl3

Tank 

Level

Pressure Filtration

Flow

rate

Totalizer to 

Distribution Backwash

Run Time Since 

Last BW

Totalizer Daily

Inlet TA TB Outlet

Daily 

Flow

Cal

Flow 

rate

Tank 

A

Tank 

B

Daily 

Volume

Vessel 

A

Vessel 

B

Vessel 

A

Vessel 

B

Vessel 

A

Vessel 

B

hr hr hr hr in in psig psig psig psig gpm kgal gpm No. No. kgal hr hr

44

Mon 09/24/07 1:00 1515.3 1516.4 5.9 5.4 23.3 30.0 39 26 27 12 202 67 197 244 245 2.3 4.0 3.6

Tue 09/25/07 6:30 1520.6 1521.8 5.3 5.4 22.5 27.8 35 27 28 12 210 67 207 245 246 2.5 1.2 0.9

Wed 09/26/07 1:30 1531.2 1532.3 10.6 10.5 21.8 23.5 37 26 27 12 203 128 203 246 247 2.3 3.7 3.3

Sun 09/30/07 1:30 1534.9 1536.0 3.7 3.7 20.3 37.3 40 25 25 12 196 43 195 246 247 0.0 7.4 7.0

45

Mon 10/01/07 2:30 1538.3 1539.5 3.4 3.5 19.8 35.8 35 26 27 12 207 67 323 247 248 2.4 2.8 2.4

Tue 10/02/07 6:00 1552.3 1553.4 14.0 13.9 17.5 30.3 35 26 27 12 212 169 202 249 250 4.5 0.5 0.1

Fri 10/05/07 6:00 1558.8 1559.5 6.5 6.1 16.3 27.5 39 25 25 12 197 77 204 249 250 0.0 7.0 6.5

46

Mon 10/08/07 7:30 1565.2 1566.3 6.4 6.8 15.3 25.0 37 24 26 12 202 79 199 250 251 2.4 5.3 4.9

Tue 10/10/07 7:00 1575.1 1576.1 9.9 9.8 13.5 20.5 34 26 27 12 207 122 206 252 253 4.4 1.7 1.3

Fri 10/12/07 7:30 1586.3 1587.3 11.2 11.2 11.5 15.5 37 25 26 12 202 129 193 253 254 2.2 4.8 4.5

47

Mon 10/15/07 5:30 1591.4 1592.5 5.1 5.2 10.8 13.3 34 26 27 12 208 68 220 254 255 2.3 1.9 1.5

Tue 10/17/07 7:00 1599.9 1600.9 8.5 8.4 31.5 34.3 35 26 26 12 206 102 200 255 256 2.4 2.2 1.8

Fri 10/19/07 6:00 1609.9 1610.9 10.0 10.0 29.8 30.3 36 25 26 12 202 120 200 256 257 2.2 4.1 3.7

48

Mon 10/22/07 4:00 1619.6 1620.6 9.7 9.7 28.5 26.3 36 24 26 12 200 116 199 257 258 2.3 5.7 5.3

Tue 10/24/07 6:00 1632.1 1633.1 12.5 12.5 26.8 21.0 34 26 27 12 205 152 203 259 260 4.7 2.0 1.7

Fri 10/26/07 8:00 1639.0 1640.0 6.9 6.9 25.5 18.0 33 26 27 12 210 82 199 260 261 2.3 0.8 0.4

49

Mon 10/29/07 6:00 1648.4 1649.4 9.4 9.4 24.5 13.5 35 26 27 12 205 115 204 261 262 2.3 2.2 1.8

Tue 10/30/07 7:30 1658.7 1659.7 10.3 10.3 22.5 33.5 37 25 26 12 200 123 199 262 263 2.2 4.4 4.0

Wed 10/31/07 6:00 1661.9 1663.0 3.2 3.3 22.3 32.3 39 24 25 12 195 38 193 262 263 0.0 7.6 7.3

Thu 11/01/07 6:00 1666.1 1667.2 4.2 4.2 21.8 30.3 35 25 25 12 204 53 211 263 264 2.4 3.7 3.3

Fri 11/02/07 6:00 1673.0 1674.0 6.9 6.8 20.5 27.5 34 25 26 12 206 83 202 264 265 2.3 2.5 2.1

Sat 11/03/07 6:00 1678.8 1681.0 5.8 7.0 19.3 24.5 33 25 26 12 208 83 215 265 266 2.3 1.3 0.9

Sun 11/04/07 6:00 1687.3 1688.4 8.5 7.4 18.0 21.5 33 26 27 12 208 90 189 266 267 2.4 0.6 0.2

50

Mon 11/05/07 5:30 1693.1 1694.2 5.8 5.8 17.0 18.8 38 24 26 12 200 69 198 266 267 0.0 6.4 6.0

Tue 11/06/07 6:00 1698.8 1699.9 5.7 5.7 16.0 16.3 36 25 26 12 201 69 202 267 268 2.3 4.0 3.6

Wed 11/07/07 6:00 1706.7 1707.7 7.9 7.8 14.8 29.3 35 25 26 12 202 95 201 268 269 2.3 3.8 3.4

Thu 11/08/07 6:00 1712.4 1713.6 5.7 5.9 13.8 26.8 34 26 27 12 207 70 200 269 270 2.4 1.5 1.1

Fri 11/09/07 6:00 1716.7 1717.7 4.3 4.1 13.0 25.0 37 25 25 12 199 49 195 269 270 0.0 5.7 5.2

Sat 11/10/07 6:00 1720.4 1721.6 3.7 3.9 12.5 23.5 34 26 27 12 207 47 207 270 271 2.3 1.4 1.0

Sun 11/11/07 6:00 1724.1 1723.4 3.7 1.8 11.8 21.8 37 24 26 12 199 44 269 270 271 0.0 5.3 4.8

51

Mon 11/12/07 5:30 1728.7 1729.9 4.6 6.5 10.8 19.5 37 24 27 12 207 55 166 271 272 2.3 1.5 1.1

Wed 11/14/07 6:00 1733.9 1735.2 5.2 5.3 32.8 35.8 39 24 26 12 196 62 197 271 272 0.0 6.7 6.5

Thu 11/15/07 6:00 1738.7 1740.0 4.8 4.8 32.0 34.0 36 25 26 12 202 58 202 272 273 2.3 3.4 3.0

Fri 11/16/07 6:00 1744.2 1745.4 5.5 5.4 31.3 32.0 36 26 27 12 208 66 201 273 274 2.4 0.8 0.3

Sat 11/17/07 5:30 1749.9 1751.0 5.7 5.6 30.8 29.8 38 24 25 12 196 67 198 273 274 0.0 6.5 5.9

Sun 11/18/07 5:30 1755.2 1756.3 5.3 5.3 29.8 27.5 39 25 26 12 202 65 203 274 275 2.3 3.7 3.2

52

Mon 11/19/07 5:30 1760.9 1762.2 5.7 5.9 28.8 25.0 34 26 27 12 206 70 200 275 276 2.3 1.4 0.9

Tue 11/20/07 6:00 1765.8 1767.1 4.9 4.9 28.0 23.0 34 24 26 12 197 57 195 275 276 0.0 6.2 5.8

Wed 11/21/07 6:00 1770.0 1771.3 4.2 4.2 27.5 21.0 38 26 26 12 204 52 206 276 277 2.3 2.3 1.9

Thu 11/22/07 5:30 1773.9 1775.2 3.9 3.9 26.8 19.3 38 25 25 12 199 46 196 276 277 0.0 6.2 5.8

Fri 11/23/07 6:00 1781.2 1782.6 7.3 7.4 25.8 16.0 37 25 26 12 198 88 200 277 278 2.4 5.4 5.1

Sat 11/24/07 6:30 1788.1 1789.4 6.9 6.8 24.8 34.8 37 24 26 12 198 83 201 278 279 2.3 4.2 3.8
US EPA Arsenic Demonstration Project at Three Forks, MT - Daily System Operation (Continued)

A7

Week 

No. Day Date Time

Run Time

12.5%

Cl2

Tank

Level

35% 

FeCl3

Tank 

Level

Pressure Filtration

Flow

rate

Totalizer to 

Distribution Backwash

Run Time Since 

Last BW

Totalizer Daily

Inlet TA TB Outlet

Daily 

Flow

Cal

Flow 

rate

Tank 

A

Tank 

B

Daily 

Volume

Vessel 

A

Vessel 

B

Vessel 

A

Vessel 

B

Vessel 

A

Vessel 

B

hr hr hr hr in in psig psig psig psig gpm kgal gpm No. No. kgal hr hr

Sun 11/25/07 5:00 1795.7 1797.0 7.6 7.6 23.5 31.8 36 26 26 12 202 91 200 279 280 2.3 3.7 3.3

53

Mon 11/26/07 5:30 1802.4 1803.8 6.7 6.8 22.5 29.0 35 25 27 12 203 81 199 280 281 2.4 2.4 2.0

Tue 11/27/07 8:00 1815.4 1816.7 13.0 12.9 20.5 23.8 38 25 25 12 197 177 228 281 282 2.0 7.3 6.9

Wed 11/28/07 6:00 1818.8 1821.1 3.4 4.4 19.5 21.5 35 25 26 12 204 54 230 282 283 2.6 3.5 3.1

Thu 11/29/07 6:00 1825.4 1827.2 6.6 6.1 18.8 35.0 34 26 27 12 206 73 193 283 284 2.3 1.6 1.1

Fri 11/30/07 6:00 1829.7 1830.9 4.3 3.7 18.0 33.5 37 25 26 12 197 45 187 283 284 0.0 5.3 4.9

Sat 12/01/07 6:00 1833.7 1834.9 4.0 4.0 17.3 32.0 34 26 27 12 208 48 202 284 285 2.4 1.2 0.7

Sun 12/02/07 5:00 1837.5 1838.7 3.8 3.8 16.8 30.5 37 25 25 12 200 46 200 284 285 0.0 5.0 4.5

54

Mon 12/03/07 5:30 1842.6 1843.9 5.1 5.2 15.8 28.3 37 25 27 12 204 62 201 285 286 2.3 2.0 1.6

Tue 12/04/07 6:00 1848.5 1849.9 5.9 6.0 14.8 25.8 39 23 25 12 194 70 195 285 286 0.0 7.9 7.0

Wed 12/05/07 6:00 1855.0 1856.4 6.5 6.5 13.8 23.0 37 24 26 12 198 79 203 286 287 2.3 6.4 6.0

Thu 12/06/07 6:00 1859.8 1861.1 4.8 4.7 13.0 36.8 35 25 26 12 206 58 204 287 288 2.2 3.0 2.6

Fri 12/07/07 6:00 1866.0 1867.4 6.2 6.3 11.8 34.0 34 25 26 12 208 76 202 288 289 2.3 1.2 0.8

Sat 12/08/07 6:30 1872.9 1874.2 6.9 6.8 33.3 31.5 33 23 25 12 195 81 196 288 289 0.0 8.0 7.6

Sun 12/09/07 6:00 1879.8 1881.1 6.9 6.9 32.3 28.5 38 24 25 12 196 84 204 289 290 2.3 6.9 6.4

55

Mon 12/10/07 6:00 1886.1 1889.1 6.3 8.0 31.3 25.3 36 25 25 12 200 76 177 290 291 2.5 5.0 4.6

Tue 12/11/07 7:00 1892.8 1894.6 6.7 5.5 30.3 23.0 35 25 26 12 202 81 220 291 292 2.2 3.6 3.2

Wed 12/12/07 6:00 1899.1 1900.4 6.3 5.8 29.0 20.0 35 25 26 12 206 77 211 292 293 2.2 1.8 1.4

Fri 12/14/07 8:30 1904.5 1905.8 5.4 5.4 28.5 18.0 34 24 25 12 196 64 196 292 293 0.0 7.2 6.8

56

Mon 12/17/07 5:30 1909.8 1911.1 5.3 5.3 27.5 34.2 37 24 26 12 199 64 203 293 294 2.3 4.4 4.1

Wed 12/19/07 7:00 1915.6 1917.0 5.8 5.9 26.8 32.0 35 25 26 12 203 70 198 294 295 2.3 2.1 1.8

Fri 12/21/07 7:00 1919.6 1921.0 4.0 4.0 26.0 30.5 38 24 26 12 197 47 196 294 295 0.0 6.1 5.9

57

Mon 12/24/07 5:00 1924.5 1925.8 4.9 4.8 25.3 28.3 38 25 26 12 200 59 202 295 296 2.3 2.9 2.4

Wed 12/26/07 8:24 1927.0 1929.0 2.5 3.2 25.0 27.3 38 25 25 12 198 30 174 295 296 0.0 5.5 4.9

Fri 12/28/07 9:00 1933.3 1934.7 6.3 5.7 24.0 24.5 35 24 25 12 201 76 211 296 297 2.5 3.6 3.2

Sat 12/29/07 11:00 1939.9 1941.3 6.6 6.6 22.8 21.8 34 25 26 12 205 80 202 297 298 2.3 2.1 1.8

58

Mon 12/31/07 9:00 1945.3 1946.8 5.4 5.5 21.8 19.3 37 23 24 12 197 63 191 297 298 0.0 7.5 7.2

Wed 01/02/08 9:00 1954.9 1956.4 9.6 9.6 20.3 15.0 32 25 26 12 209 118 204 299 300 4.6 0.9 0.5

Fri 01/04/08 9:00 1964.6 1966.1 9.7 9.7 18.8 33.0 33 24 25 12 205 117 200 300 301 2.4 2.5 2.1

Sat 01/05/08 14:30 1973.8 1975.3 9.2 9.2 17.0 29.5 35 24 26 12 204 110 199 301 302 2.3 3.6 3.2

59

Mon 01/07/08 10:00 1980.9 1982.4 7.1 7.1 15.8 26.5 33 24 25 12 205 86 202 302 303 2.3 2.6 2.2

Wed 01/09/08 13:00 1991.3 1992.8 10.4 10.4 14.0 32.8 35 24 24 12 202 124 199 303 304 2.3 4.9 4.5

Fri 01/11/08 10:30 2001.4 2002.9 10.1 10.1 12.0 28.8 36 23 24 12 200 120 198 304 305 2.2 6.9 6.5

Sat 01/12/08 15:00 2004.5 2011.1 3.1 8.2 10.8 25.3 36 24 24 12 197 98 288 305 306 2.3 6.9 6.5

60 Mon 01/14/08 13:00 2016.1 2017.6 11.6 6.5 9.5 22.5 36 23 25 12 199 81 149 306 307 2.3 5.4 5.8

61

Mon 01/21/08 9:00 2025.8 2027.2 9.7 9.6 7.8 18.3 38 22 24 12 195 114 198 307 308 2.3 6.8 6.5

Wed 01/23/08 9:30 2034.4 2030.9 8.6 3.7 29.0 33.8 36 23 25 12 198 105 283 308 309 2.3 7.5 7.1

Fri 01/25/08 8:00 2042.0 2043.0 7.6 12.1 28.0 30.8 36 23 25 12 198 88 149 309 310 1.9 7.0 6.0

62

Mon 01/28/08 8:00 2049.1 2050.6 7.1 7.6 26.8 27.8 36 23 25 12 202 91 206 310 311 2.7 6.0 5.6

Wed 01/30/08 8:00 2058.5 2060.0 9.4 9.4 25.3 34.5 36 23 24 12 198.7 113 200 311 312 2.3 7.3 6.9

Fri 02/01/08 8:00 2067.8 2068.9 9.3 8.9 24.0 31.0 55 3 33 12 140 108 197 312 313 2.3 0.0 7.7
US EPA Arsenic Demonstration Project at Three Forks, MT - Daily System Operation (Continued)

A8

Week 

No. Day Date Time

Run Time

12.5%

Cl2

Tank

Level

35% 

FeCl3

Tank 

Level

Pressure Filtration

Flow

rate

Totalizer to 

Distribution Backwash

Run Time Since 

Last BW

Totalizer Daily

Inlet TA TB Outlet

Daily 

Flow

Cal

Flow 

rate

Tank 

A

Tank 

B

Daily 

Volume

Vessel 

A

Vessel 

B

Vessel 

A

Vessel 

B

Vessel 

A

Vessel 

B

hr hr hr hr in in psig psig psig psig gpm kgal gpm No. No. kgal hr hr

63 Mon 02/04/08 7:30 2075.9 2077.4 8.1 8.5 22.5 27.5 32 25 26 12 212 104 208 314 315 4.5 0.4 0.4

Fri 02/08/08 6:30 2084.8 2086.3 8.9 8.9 21.0 23.5 32 24 26 12 208 131 245 315 316 2.3 1.2 0.8

Highlighted columns indicate calculated values.

Note: Chemical drums are tapered; Cl2 and FeCl3 levels measured from bottom of drum. 

Note: Backwash wastewater supernatant recycled until 12/12/06. Afterwards, wastewater discharged to sewer.

Note: Run time until 02/16/07 estimated by Well No. 2 Hour Meter.

NA = data not available
APPENDIX B

ANALYTICAL DATA TABLES
B1

Analytical Results from Long-Term Sampling at Three Forks, MT

Parameter Unit

266 270 262 271 271 280 272 279 267 265 267 287 280 284 284 271 275 275

- - - - - - - - - - - - - - - - - -

Fluoride mg/L 3.0 3.1 3.0 - - - - - - - - 2.2 2.1 2.2 - - - -

Sulfate mg/L 21 20 21 - - - - - - - - 20 20 20 - - - -

Nitrate (as N) mg/L 0.4 0.4 0.3 - - - - - - - - 0.3 0.3 0.3 - - - -

17.1 21.3 11.7 <10 <10 <10 <10 22.4 20.8 <10 <10 45.2 44.3 18.6 24.8 22.6 <10 <10

- - - - - - - - - - - - - - - - - -

48.5 48.8 47.8 47.0 47.1 45.9 45.8 47.5 48.0 47.0 46.7 50.8 51.0 50.3 48.2 48.5 47.5 47.9

- - - - - - - - - - - - - - - - - -

0.4 1.8 0.9 0.1 1.8 0.8 0.9 <0.1 1.0 0.3 0.3 1.1 1.9 0.7 0.3 1.6 0.6 0.8

- - - - - - - - - - - - - - - - - -

pH S.U. 7.4 7.7 7.8 7.8 7.3 7.8 7.6 7.3 7.2 7.2 7.3 7.4 7.2 7.2 7.3 7.1 7.1 7.1

Temperature °C 13.3 12.9 12.7 12.7 13.5 12.4 12.5 12.3 12.3 12.4 12.3 15.7 15.7 15.8 12.3 11.8 11.8 11.6

DO mg/L 3.3 2.4 3.1 2.7 3.9 2.7 2.5 NA(b) NA(b) NA(b) NA(b) 2.5 1.8 2.1 2.4 2.1 2.2 2.1

ORP mV 335 281 321 312 468 503 524 262 295 327 313 249 317 363 251 314 384 390

Free Chlorine mg/L - 0.5 0.8 - 0.4 0.4 0.5 - 0.6 0.6 0.5 - 0.6 0.6 - 0.7 0.6 0.7

Total Chlorine mg/L - 0.4 1.0 - 0.5 0.5 0.5 - 0.6 0.5 0.5 - 0.7 0.6 - 0.6 0.6 0.6

Total Hardness (as CaCO3) mg/L 181 184 178 - - - - - - - - 222 248 256 - - - -

Ca Hardness (as CaCO3) mg/L 128 132 129 - - - - - - - - 167 196 204 - - - -

Mg Hardness (as CaCO3) mg/L 52.3 52.1 49.3 - - - - - - - - 54.8 51.7 51.6 - - - -

59.8 61.2 28.3 64.4 72.2 17.3 30.6 78.5 74.1 18.5 25.5 90.7 90.5 16.8 95.1 94.0 13.3 13.0

- - - - - - - - - - - - - - - - - -

As (soluble) μg/L 59.7 5.9 4.8 - - - - - - - - 80.4 11.7 7.2 - - - -

As (particulate) μg/L 0.1 55.4 23.5 - - - - - - - - 10.3 78.7 9.6 - - - -

As (III) μg/L 0.6 0.9 1.6 - - - - - - - - 1.4 1.3 1.2 - - - -

As (V) μg/L 59.0 5.0 3.2 - - - - - - - - 79.0 10.4 6.0 - - - -

<25 2,502 936 <25 1,153 323 561 <25 1,527 236 410 <25 1,604 225 <25 1,754 134 139

- - - - - - - - - - - - - - - - - -

Fe (soluble) μg/L <25 42 <25 - - - - - - - - <25 38 <25 - - - -

<0.1 15.4 8.5 0.1 12.3 5.5 7.2 <0.1 8.5 3.4 4.1 0.1 9.7 3.2 <0.1 7.5 0.5 0.6

- - - - - - - - - - - - - - - - - -

Mn (soluble) μg/L <0.1 6.3 4.9 - - - - - - - - 0.4 3.2 2.7 - - - -

(a) Stroke of iron addition pump reduced from 28 to 21 on 12/08/06. (b) DO probe not operational. (c) Media bed modifications performed 03/13/07.

03/21/07(c) 03/28/07

IN AC TT IN AC TA TB

As (total) μg/L

12/05/06 12/12/06(a)

IN AC TA TB IN AC TA TB

11/29/06

mg/L

Total P (as P) μg/L

AC TT Sampling Location IN

Turbidity NTU

Sampling Date

Mn (total) μg/L

Fe (total) μg/L

Silica (as SiO2) mg/L

Alkalinity (as CaCO3)
B2

Analytical Results from Long-Term Sampling at Three Forks, MT (Continued)

Parameter Unit

282 284 279 274 296 288 286 291 288 288 288 297 302 295 290 - - - -

- - - - - - - - - - - 295 287 287 290 - - - -

Fluoride mg/L - - - - - - - - 2.1 2.2 2.2 - - - - - - - -

Sulfate mg/L - - - - - - - - 22 22 22 - - - - - - - -

Nitrate (as N) mg/L - - - - - - - - 0.3 0.4 0.3 - - - - - - - -

36.5 34.7 <10 <10 53.7 53.5 15.6 14.8 42.9 43.5 11.0 28.0 28.4 <10 <10 - - - -

- - - - - - - - - - - 25.1 25.0 <10 <10 - - - -

46.8 46.4 45.6 45.6 47.4 47.9 47.4 47.0 49.7 50.3 49.5 49.1 49.3 49.2 49.1 - - - -

- - - - - - - - - - - 49.5 49.7 49.2 47.9 - - - -

0.3 1.6 0.8 0.6 0.9 3.3 1.5 0.8 0.5 1.5 0.4 0.3 1.4 0.5 0.4 - - - -

- - - - - - - - - - - 0.4 0.6 0.3 0.7 - - - -

pH S.U. 7.5 7.2 7.2 7.1 7.7 7.9 7.9 7.9 7.4 7.8 7.9 7.7 7.9 7.8 8.0 7.6 7.7 7.7 7.7

Temperature °C 11.3 10.5 10.3 10.5 11.9 11.8 11.7 11.7 11.6 11.1 11.1 10.7 10.5 10.6 10.4 13.7 13.3 13.4 13.3

DO mg/L 3.1 2.7 2.7 2.7 2.2 1.7 1.6 1.7 2.6 2.3 2.0 2.1 1.9 2.5 1.5 3.0 2.6 2.9 2.8

ORP mV 325 355 348 321 242 294 314 353 239 287 308 258 301 327 353 251 507 523 548

Free Chlorine mg/L - 0.5 0.5 0.7 - 0.7 0.6 0.7 - 0.9 0.8 - 1.0 0.9 1.0 - 3.2 3.1 2.7

Total Chlorine mg/L - 0.5 0.4 0.5 - 0.6 0.5 0.6 - 0.9 0.8 - 1.0 1.0 1.0 - 3.2 2.8 3.1

Total Hardness (as CaCO3) mg/L - - - - - - - - 195 202 213 - - - - - - - -

Ca Hardness (as CaCO3) mg/L - - - - - - - - 145 151 157 - - - - - - - -

Mg Hardness (as CaCO3) mg/L - - - - - - - - 50.6 51.0 55.1 - - - - - - - -

92.8 90.5 22.4 22.8 91.1 91.9 16.6 15.6 91.7 90.4 17.0 96.7 95.0 15.5 14.8 80.5 79.6 8.4 8.2

- - - - - - - - - - - 82.9 86.8 12.3 12.5 - - - -

As (soluble) μg/L - - - - - - - - 85.5 10.7 5.8 - - - - 81.7 6.3 4.4 3.8

As (particulate) μg/L - - - - - - - - 6.2 79.8 11.2 - - - - <0.1 73.3 4.0 4.5

As (III) μg/L - - - - - - - - <0.1 <0.1 <0.1 - - - - - - - -

As (V) μg/L - - - - - - - - 85.4 10.6 5.7 - - - - - - - -

<25 1,650 309 338 <25 1,373 161 156 <25 2,277 229 <25 2,053 153 145 <25 2,301 111 96

- - - - - - - - - - - <25 1,990 147 155 - - - -

Fe (soluble) μg/L - - - - - - - - <25 39 <25 - - - - <25 <25 <25 <25

<0.1 9.2 3.0 3.1 <0.1 9.9 2.9 2.9 0.1 10.7 3.5 <0.1 10.1 2.4 2.4 - - - -

- - - - - - - - - - - <0.1 9.6 2.2 2.2 - - - -

Mn (soluble) μg/L - - - - - - - - 0.1 3.1 2.6 - - - - - - - -

(a) Stroke of chlorine addition pump increased from 20 to 30 on 04/16/07. (b) Addition of FeCl3/polymer blend began 07/06/07. Stroke of iron addition pump set at 25. 

Samples collected 2.7 hr after backwash.

07/17/07(b)

IN AC TA TB

04/25/07

IN AC TT

04/18/07(a)

IN AC TA TB

As (total) μg/L

mg/L

Total P (as P) μg/L

Sampling Location

Turbidity NTU

Sampling Date

Mn (total) μg/L

Fe (total) μg/L

Silica (as SiO2) mg/L

Alkalinity (as CaCO3)

04/04/07

IN AC TA TB

04/11/07

IN AC TA TB