EPA/600/R-10/040 

April 2010 

Arsenic Removal from Drinking Water by Adsorptive Media

U.S. EPA Demonstration Project at 

Webb Consolidated Independent School District in Bruni, TX

Final Performance Evaluation Report

by

Shane Williams* 

Abraham S.C. Chen** 

Lili Wang** 

*

Battelle, Columbus, OH 43201-2693 **ALSA Tech, LLC, Columbus, OH 43219-0693 

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, OH 45268 

National Risk Management Research Laboratory

Office of Research and Development

U.S. Environmental Protection Agency 

Cincinnati, OH 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 groundwater; prevention and control of indoor air pollution; and restoration of ecosystems. 

NRMRL collaborates with both public and private sector partners to foster technologies that reduce the 

cost of compliance and 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 and the results obtained from the arsenic removal 

treatment technology demonstration project at the Webb Consolidated Independent School District (Webb 

CISD) in Bruni, TX. The main objective of the project was to evaluate the effectiveness of AdEdge 

Technologies’ AD-33 media in removing arsenic to meet the new arsenic maximum contaminant level 

(MCL) of 10 μg/L. Additionally, this project evaluated 1) the reliability of the treatment system (Arsenic 

Package Unit [APU]-50LL-CS-S-2-AVH), 2) the required system operation and maintenance (O&M) and 

operator skills, and 3) the capital and O&M cost of the technology. The project also characterized the 

water in the distribution system and residuals produced by the treatment process. The types of data 

collected include system operation, water quality (both across the treatment train and in the distribution 

system), process residuals, and capital and O&M cost.

The treatment system consisted of two 42-in × 72-in carbon steel vessels in series configuration, each 

containing approximately 22 ft3 of AD-33 pelletized media, which is an iron-based adsorptive media 

developed by Bayer AG and marketed under the name of AD-33 by AdEdge Technologies. The 

treatment system was designed for a peak flowrate of 40 gal/min (gpm) and an empty bed contact time 

(EBCT) of approximately 4.1 min per vessel. Over the performance evaluation period, the actual average 

flowrate was estimated at 40 gpm (although with quite a bit of fluctuation), based on readings of an hour 

meter interlocked to the well pump and the electromagnetic flow meter/totalizer installed on each 

adsorption vessel. 

As part of the water treatment system, a pH adjustment/control system was used to adjust pH values of 

raw water from as high as 8.3 to a target value of 7.0. A prechlorination system also was used to oxidize 

As(III) to As(V) and maintain a target chlorine residual level of 1.2 mg/L (as Cl2) in the distribution 

system. The pH adjustment/control system consisted of a carbon dioxide (CO2) supply assembly, an 

automatic pH control panel, a CO2 membrane module (that injected CO2 into a CO2 loop), and an inline 

pH probe. The prechlorination system, which was upgraded from the pre-existing system, included a 

chemical feed pump, a sodium hypochlorite (NaOCl) feed tank, and an inject port located downstream of 

the CO2 loop and inline pH probe. 

The treatment system began regular operation on December 8, 2005. The data collected included system 

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

and capital and O&M cost. Between December 8, 2005, and June 29, 2007, the treatment system treated 

5,658,728 gal of water. Since then, a system operator was not available and therefore system 

measurements were sporadic from June 30, 2007 through the end of the system performance evaluation 

on May 15, 2008. Based on an average daily operating time of 4.2 hr/day and total number of operational 

days (i.e., 889 days), the total amount of water treated was estimated at 8,841,000 gal. This estimated

volume throughput was equivalent to 27,000 bed volumes (BV) based on the 44 ft3

 of media in both lead 

and lag vessels.

Since system startup, the treatment system has experienced component failures associated with the pH 

control system and flow meters/totalizers. Leaks were detected in the CO2 supply line; the proportional 

flow control valve malfunctioned; and the inline pH probe failed. There were periods when the pH 

control system was switched from automatic to manual mode until replacement of certain system 

components were performed to address the problems encountered. In addition, errors were encountered 

with the system flow meters/totalizers. On two occasions, the system totalizers reset and began totalizing 

from zero, likely caused by a programming error. In the first few months of the performance evaluation 

study, the issues with the pH control system were resolved and programming updates were prepared to

prevent future totalizer errors. On June 29, 2007, the licensed system operator working for Webb CISD 
v

resigned, which impeded the data collection efforts for the remainder of the system performance 

evaluation. Operational and water quality data provided by Webb CISD after June 29, 2007, were 

collected by a temporary operator who was not formally trained on operating the system. 

Total arsenic concentrations in raw water ranged from 46.0 to 68.7 μg/L. Soluble As(III) was the 

predominating species, ranging from 31.3 to 42.0 μg/L. Chlorine effectively oxidized soluble As(III) to 

soluble As(V), reducing soluble As(III) concentrations to an average value of 1.2 μg/L. At the end of the 

performance evaluation study on May 15, 2008, total arsenic levels in the treated water were 45.4 and 5.2 

μg/L following the lead and lag adsorption vessels, respectively. Concentrations of phosphorus and 

silica, which could interfere with arsenic adsorption by competing with arsenate for adsorption sites, 

ranged from <10.0 to 13.7 mg/L (as P) and from 39.1 to 43.9 mg/L (as SiO2), respectively, in raw water. 

Concentrations of iron, manganese, and other ions in raw water were not high enough to impact arsenic 

removal by the media. 

Comparison of the distribution system sampling results before and after operation of the system showed a 

significant decrease in arsenic concentration (from an average of 68.7 μg/L to an average of 2.4 μg/L). 

The arsenic concentrations in the distribution system were similar to those in the system effluent. Lead 

and copper concentrations appeared to have been affected to some extent by the operation of the treatment 

system. However, the effects were not trendy, with the lead concentrations becoming mostly lower and 

the copper concentrations becoming mostly higher after system startup. 

The capital investment cost of $138,642 included $94,662 for equipment, $24,300 for site engineering, 

and $19,680 for installation. Using the system’s rated capacity of 40 gpm (or 57,600 gal/day [gpd]), the 

capital cost was $3,466/gpm (or $2.41/gpd) of design capacity. The capital cost also was converted to an 

annualized cost of $13,086/yr using a capital recovery factor (CRF) of 0.09439 based on a 7% interest 

rate and a 20-year return period. Assuming that the system operated 24 hours a day, 7 days a week at the 

system design flowrate of 40 gpm to produce 21,024,000 gal of water per year, the unit capital cost would 

be $0.62/1,000 gal. Because the system operated an average of 4.2 hr/day at 40 gpm, producing an 

estimated 3,679,200 gal of water annually, the unit capital cost increased to $3.56/1,000 gal at this 

reduced rate of use. 

The O&M cost included only the cost associated with the adsorption system, such as media replacement 

and disposal, CO2 and chlorine usage, electricity consumption, and labor. Although media replacement 

did not occur during the system performance evaluation, the media replacement cost would have 

represented the majority of the O&M cost and was estimated to be $11,190 to change out one vessel 

(including 22 ft3 AD-33 media and associated labor for media changeout and disposal). 
vi

CONTENTS

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

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

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

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

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

TABLES ..................................................................................................................................................... vii

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

ACKNOWLEDGMENTS ........................................................................................................................... xi

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 ........................................................................................................... 6

3.1 General Project Approach ............................................................................................................. 6

3.2 System O&M and Cost Data Collection ....................................................................................... 7

3.3 Sample Collection Procedures and Schedules .............................................................................. 7

3.3.1 Source Water Sample Collection ..................................................................................... 9

3.3.2 Treatment Plant Water Sample Collection ...................................................................... 9

3.3.3 Backwash Wastewater/Solids and Spent Media Collection ............................................ 9

3.3.4 Distribution System Water Sample Collection ................................................................ 9

3.4 Sampling Logistics ........................................................................................................................ 9

3.4.1 Preparation of Arsenic Speciation Kits ............................................................................ 9

3.4.2 Preparation of Sampling Coolers ................................................................................... 10

3.4.3 Sample Shipping and Handling ..................................................................................... 10

3.5 Analytical Procedures ................................................................................................................. 10

4.0 RESULTS AND DISCUSSION .......................................................................................................... 11

4.1 Facility Description and Pre-existing Treatment System Infrastructure ..................................... 11

4.1.1 Source Water Quality .................................................................................................... 11

4.1.2 Treated Water Quality. .................................................................................................. 14

4.1.3 Distribution System ....................................................................................................... 14

4.2 Treatment Process Description ................................................................................................... 15

4.3 System Installation ...................................................................................................................... 24

4.3.1 Permitting ...................................................................................................................... 24

4.3.2 Building Preparation ...................................................................................................... 24

4.3.3 Installation, Shakedown, and Startup ............................................................................ 24

4.4 System Operation ........................................................................................................................ 26

4.4.1 Operational Parameters .................................................................................................. 26

4.4.2 Residual Management ................................................................................................... 30

4.4.3 System/Operation Reliability and Simplicity ................................................................ 30

4.5 System Performance ................................................................................................................... 32

4.5.1 Treatment Plant Sampling ............................................................................................. 32

4.5.2 Backwash Wastewater Sampling ................................................................................... 39

4.5.3 Distribution System Water Sampling ............................................................................ 39

4.6 System Cost ................................................................................................................................ 41
vii

4.6.1 Capital Cost ................................................................................................................... 41

4.6.2 Operation and Maintenance Cost................................................................................... 42

5.0 REFERENCES .................................................................................................................................... 45

APPENDICES

Appendix A: OPERATIONAL DATA

Appendix B: ANALYTICAL DATA

FIGURES

Figure 4-1. Pre-existing Water Treatment Facility .............................................................................. 11

Figure 4-2. Wellhead at Webb CISD ................................................................................................... 12

Figure 4-3. Pre-existing Chlorine Addition System ............................................................................ 12

Figure 4-4. Process Flow Diagram for the APU-50LL-CS-S-2-AVH System .................................... 17

Figure 4-5. Process Flow Diagram and Sampling Schedules and Locations ...................................... 18

Figure 4-6. Process Diagram of CO2 pH Adjustment System and pH/PID Control Panel .................. 20

Figure 4-7. Carbon Dioxide Gas Flow Control System for pH Adjustment ....................................... 21

Figure 4-8. Chlorination Feed System ................................................................................................. 22

Figure 4-9. Adsorption System Valve Tree and Piping Configuration ............................................... 23

Figure 4-10. Maintenance Shop Building .............................................................................................. 25

Figure 4-11. System Delivery to Site .................................................................................................... 25

Figure 4-12. System Instantaneous and Calculated Flowrates .............................................................. 28

Figure 4-13a. System Operational Pressure Readings ............................................................................ 29

Figure 4-13b. Vessel A Operational Pressure Readings .......................................................................... 29

Figure 4-13c. Vessel B Operational Pressure Readings .......................................................................... 30

Figure 4-14. Concentrations of Various Arsenic Species at IN, AP, TA, and TB Sampling 

Locations ........................................................................................................................... 36

Figure 4-15. Total Arsenic Breakthrough Curves ................................................................................. 37

Figure 4-16. Silica (as SiO2) Breakthrough Curves ............................................................................... 37

Figure 4-17. pH Values Across Treatment Train Versus Throughput ................................................. 38

Figure 4-18. Media Replacement and Other Operation and Maintenance Cost .................................... 44

TABLES

Table 1-1. Summary of Round 1 and Round 2 Arsenic Removal Demonstration Locations, 

Technologies, and Source Water Quality ............................................................................... 3

Table 3-1. Predemonstration Study Activities and Completion Dates .................................................... 6

Table 3-2. Evaluation Objectives and Supporting Data Collection Activities ........................................ 7

Table 3-3. Sampling Schedules and Analytes ......................................................................................... 8

Table 4-1. Water Quality Data for Webb CISD, Bruni, TX .................................................................. 13

Table 4-2. TCEQ Treated Water Quality Data ...................................................................................... 14

Table 4-3. Physical and Chemical Properties of AD-33 Media ............................................................ 15

Table 4-4. Design Specifications for AdEdge APU-50LL-CS-S-2-AVH System ................................ 19

Table 4-5. Properties of Celgard®, X50-215 Microporous Hollow Fiber Membrane ........................... 21

Table 4-6. System Punch-List/Operational Issues ................................................................................. 26

Table 4-7. Summary of APU-50LL-CS-S-2-AVH System Operation .................................................. 27
viii

Table 4-8. Summary of Analytical Results for Arsenic, Iron, and Manganese ..................................... 33

Table 4-9. Summary of Water Quality Parameter Sampling Results .................................................... 34

Table 4-10. Distribution System Sampling Results ................................................................................. 40

Table 4-11. Capital Investment Cost for APU-50LL-CS-S-2-AVH System........................................... 41

Table 4-12. Operation and Maintenance Cost for APU-50LL-CS-S-2-AVH System ............................ 43
ix

ABBREVIATIONS AND ACRONYMS

Δp differential pressure

AAL American Analytical Laboratories

AM adsorptive media 

APU arsenic package unit

As arsenic

ATS Aquatic Treatment Systems

ATSI Applied Technology Systems, Inc.

BET Brunauer, Emmett, and Teller 

BV bed volume 

Ca calcium

C/F coagulation/filtration process 

CISD Consolidated Independent School District 

Cl chlorine

CRF capital recovery factor

Cu copper 

DO dissolved oxygen 

EBCT empty bed contact time 

EPA U.S. Environmental Protection Agency 

F fluorine 

Fe iron 

gpd gallons per day

gph gallons per hour 

gpm gallons per minute 

HDPE high-density polyethylene 

HIX hybrid ion exchanger 

hp horse power 

ICP-MS inductively coupled plasma-mass spectrometry

ID identification

ISFET Ion Sensitive Field Effect Transistor 

IX ion exchange 

LCR Lead and Copper Rule 

MCL maximum contaminant level

MDL method detection limit

MEI Magnesium Elektron, Inc.

Mg magnesium 

Mn manganese

mV millivolts
x

ABBREVIATIONS AND ACRONYMS (Continued)

Na sodium 

NA not analyzed

NaOCl sodium hypochlorite 

NRMRL National Risk Management Research Laboratory

NSF NSF International 

O&M operation and maintenance 

OIT Oregon Institute of Technology 

ORD Office of Research and Development

ORP oxidation-reduction potential 

PID Proportional Integral Derivative

PLC programmable logic controller 

PO4 phosphate 

POU point of use

psi pounds per square inch

PVC polyvinyl chloride 

QAPP Quality Assurance Project Plan

QA/QC quality assurance/quality control 

RO reverse osmosis

RPD relative percent difference

SDWA Safe Drinking Water Act

SiO2 silica

SMCL secondary maximum contaminant level

SO4

2- sulfate

STS Severn Trent Services

TCEQ Texas Commission on Environmental Quality 

TCLP toxicity characteristic leaching procedure

TDS total dissolved solids

U uranium 

V vanadium 

VOC volatile organic compound
xi

ACKNOWLEDGMENTS

The authors wish to extend their sincere appreciation to Webb Consolidated Independent School District 

and to Mr. George Gonzales, who monitored the treatment system and collected samples from the 

treatment and distribution systems throughout this study period. This performance evaluation would not 

have been possible without his efforts. 
1

1.0 INTRODUCTION

1.1 Background 

The Safe Drinking Water Act (SDWA) mandates that the United States Environmental Protection Agency 

(EPA) identify and regulate drinking water contaminants that may have adverse human health effects and 

are known or anticipated to occur in public water supply systems. In 1975 under the SDWA, EPA 

established a maximum contaminant level (MCL) for arsenic at 0.05 mg/L. Amended in 1996, the 

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

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

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

2003, to express the MCL as 0.010 mg/L (10 μg/L) (EPA, 2003). The final rule requires all community 

and non-transient, non-community water systems to comply with the new standard by January 23, 2006. 

In October 2001, EPA announced an initiative for additional research and development of cost-effective 

technologies to help small community water systems (<10,000 customers) meet the new arsenic standard, 

and to provide technical assistance to operators of small systems to reduce compliance cost. 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 from one to six proposals. In April 2003, an independent technical panel 

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

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

reasons, only 12 of the 17 sites were selected for the demonstration program. 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 Webb Consolidated Independent School District (CISD) in Bruni, TX 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. AdEdge Technologies (AdEdge), using the Bayoxide E33 (AD-33) 

media developed by Bayer AG, was selected for demonstration at the Webb CISD site in April 2004. 

As of April 2010, 39 of the 40 systems were operational, and the performance evaluation of 36 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, 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 process modification. Table 1-1 summarizes the locations,

technologies, vendors, system flowrates, and key source water quality parameters (including arsenic, iron, 

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 Round 1 and Round 2 arsenic demonstration program is to conduct 40 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 AdEdge system at the Webb CISD in Bruni, from 

December 8, 2005, through May 15, 2008. The data collected included system operational data, water 

quality data (both across the treatment train and in the distribution system), and capital and preliminary 

O&M cost data.
3

Table 1-1. Summary of Round 1 and Round 2 Arsenic Removal Demonstration

Locations, Technologies, and Source Water Quality

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 Round 1 and Round 2 Arsenic Removal Demonstration

Locations, Technologies, and Source Water Quality (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) Replaced Village of Lyman, NE site which withdrew from program in June 2006.

(f) Facilities upgraded systems in Springfield, OH from 150 to 250 gal/min (gpm), Sandusky, MI from 210 to 340 gpm, and Arnaudville, LA from 385 to 770 gpm. 

(g) Including nine residential units.

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

2.0 SUMMARY AND CONCLUSIONS

AdEdge’s APU-50-LL-CS-S-AVH treatment system with AD-33 pelletized media was installed and has 

operated at the Webb CISD site in Bruni, TX since December 8, 2005. Based on the information 

collected during the system evaluation period, the following summary and conclusion statements are 

provided. 

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

• Chlorine was effective in oxidizing soluble As(III) to soluble As(V). Analytical data 

confirmed that average soluble As(III) concentrations decreased from 37.5 μg/L in raw water 

to 1.2 μg/L after chlorination and that average As(V) concentrations increased 

correspondingly from 15.0 μg/L in raw water to 51.7 μg/L after chlorination. Because very 

little iron was present in raw water, little or no particulate arsenic was produced upon 

chlorination. 

• AD-33 media effectively lowered arsenic concentrations to 5.2 μg/L at the end of the 

performance evaluation study. The volume throughput was estimated at 27,000 bed volumes 

(BV), based on 44 ft3 of media in both lead and lag vessels. 

• The operation of the treatment system significantly lowered arsenic concentrations in the 

distribution system (i.e., from 68.7 to 2.4 μg/L, on average). The treatment system did not 

appear to have impacted lead or copper concentrations in the distribution system. 

Required system O&M and operator skill levels:

• The daily demand on the operator was typically 20 min to visually inspect the system and 

record operational parameters, although additional time and effort was required to 

troubleshoot the problems associated with the CO2 system. 

• Some operational problems related to the CO2 gas flow control system were 

encountered during the system operation. Primary problems included a faulty 

proportioning valve and failure of the inline pH probe. A reoccurring problem 

unrelated to the pH adjustment system was associated with the electromagnetic water 

flow meters/totalizers, which randomly reset to zero. 

• Operation of the system did not appear to require additional skills beyond those 

necessary to operate the existing water supply equipment, with the exception of the 

CO2 and pH control portion of the system. The CO2 system required additional 

operator training and safety awareness. 

Process residuals produced by the technology: 

• The pressure differential (Δp) measured across the media vessels during the system operation 

did not require a backwash. Therefore, no backwash residuals were produced. The average 

pressure drop was 13.9 psi through June 27, 2007. 

Cost-effectiveness of the technology:

• Based on the system’s rated capacity of 40 gpm (or 57,600 gal/day [gpd]), the capital cost 

was $3,466/gpm (or $2.41/gpd) of design capacity. 

• Media replacement and disposal did not occur during system performance 

evaluation; however, the cost to change out one vessel (22 ft3 AD-33 media) was 

estimated to be $11,190, which included the replacement media, spent media 

disposal, shipping, labor, and travel.
6

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 AdEdge treatment system began on December 8, 2005 and ended on May 15, 2008. Table 3-2 

summarizes the types of data collected and considered as part of the technology evaluation process. The 

overall performance of the system was determined based on its ability to consistently remove arsenic to

below the arsenic MCL of 10 μg/L through the collection of water samples across the treatment plant, as 

described in the Study Plan (Battelle, 2005). The reliability of the system was evaluated by tracking the 

unscheduled system downtime and the 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. 

Table 3-1. Predemonstration Study Activities and Completion Dates

Activity Date

Introductory Meeting Held November 15, 2004

Project Planning Meeting Held February 17, 2005

Draft Letter of Understanding Issued February 23, 2005

Final Letter of Understanding Issued March 24, 2005

Request for Quotation Issued to Vendor March 14, 2005

Vendor Quotation Received by Battelle April 1, 2005

Purchase Order Completed and Signed April 18, 2005

Engineering Plans Submitted to TCEQ June 8, 2005

System Permit Issued by TCEQ August 31, 2005

APU System Shipped and Arrived October 13, 2005

System Installation Completed November 19, 2005

System Shakedown Completed November 19, 2005

Final Study Plan Issued November 30, 2005

Performance Evaluation Begun December 8, 2005

TECQ = Texas Commission on Environmental Quality

The O&M and operator skill requirements were evaluated based on a combination of quantitative data 

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

automation, extent of preventive maintenance activities, frequency of chemical and/or media handling and 

inventory, and general knowledge needed for relevant chemical processes and related health and safety 

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

Log Sheet. 

The cost of the system was evaluated based on the capital cost per gpm (or gpd) of design capacity and 

the O&M cost per 1,000 gal of water treated. This requires tracking of the capital cost for equipment, site 

engineering, and installation, as well as the O&M cost for media replacement and disposal, CO2 and 

chlorine consumption, electrical power usage, and labor. Data on Webb CISD’s O&M cost were limited 

to CO2 and chlorine consumption, electricity usage, and labor because media replacement did not take 

place during the system performance evaluation. 
7

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

Evaluation Objectives Data Collection

Performance -Ability to consistently meet 10 μg/L of arsenic MCL 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 system 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 of relevant chemical processes and health and safety 

practices

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

process

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

-O&M cost for media replacement, electricity usage, and labor

3.2 System O&M and Cost Data Collection 

The plant operator performed daily, biweekly, and monthly system O&M and data collection according to 

instructions provided by the vendor and Battelle. On a daily basis, the plant operator recorded system 

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

Operation Log Sheet and conducted visual inspections to ensure normal system operations. If any 

problem occurred, the plant operator would contact 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 action taken, materials and supplies used, and associated cost and 

labor incurred on the Repair and Maintenance Log Sheet. Every other week, the plant operator measured 

pH, temperature, dissolved oxygen (DO), and oxidation-reduction potential (ORP), and recorded the data 

on an Onsite Water Quality Parameters Log Sheet. The Webb CISD operator resigned during the system 

performance evaluation; thus, there is no operational and water quality data after June 29, 2007. 

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. CO2 and chlorine consumption was tracked through daily measurements and recorded on Daily 

System Operation Log Sheets. Electricity consumption was tracked through the onsite electric meter. 

Labor for various activities, such as routine system O&M, system troubleshooting and repair, and 

demonstration-related work, were tracked using an Operator Labor Hour Log Sheet. The routine O&M 

included activities such as completing field logs, replenishing chemical solutions, ordering supplies, 

performing system inspections, and others as recommended by the vendor. The demonstration-related 

work, including activities such as performing field measurements, collecting and shipping samples, and 

communicating with the Battelle Study Lead and vendor, was recorded but not used for the cost analysis.

3.3 Sample Collection Procedures and Schedules

To evaluate the performance of the system, samples were collected from the wellhead, across the 

treatment plant, from the backwash discharge line, and from the distribution system. Table 3-3 provides 
8

Table 3-3. Sampling Schedules and Analytes

Sample 

Type

Sampling

Locations(a)

No. of 

Sampling

Locations Frequency Analytes

Sampling

Date

Source 

Water

At Wellhead (IN) 1 Once during 

initial site 

visit

Onsite: pH, temperature, 

DO, and ORP

Offsite: As (total and 

soluble), As(III), As(V), 

Fe (total and soluble), 

Mn (total and soluble),

U (total and soluble), 

V (total and soluble), 

Na, Ca, Mg, Cl, F, NO3, 

NO2, NH3, SO4, SiO2, 

PO4, turbidity, alkalinity, 

TDS, and TOC

11/15/04

Treatment 

Plant Water

At Wellhead (IN),

after pH 

Adjustment (AP), 

after Lead Vessel 

(TA), and after 

Lag Vessel (TB)

4 First week 

of each fourweek cycle

Onsite: pH, temperature, 

DO, ORP, and Cl2 (free 

and total)(b)

12/08/05, 01/05/06, 

02/01/06, 03/14/06, 

04/11/06, 05/09/06, 

06/06/06, 07/11/06, 

08/02/06, 08/30/06, 

09/28/06, 10/31/06, 

11/28/06, 12/12/06, 

01/22/07

Offsite: As (total and 

soluble), As(III), As(V), 

Fe (total and soluble), 

Mn (total and soluble), 

Ca, Mg, F, NO3, SO4, 

SiO2, P, turbidity, and 

alkalinity

4 Third week 

of each fourweek cycle

Onsite: pH, temperature, 

DO, ORP, and Cl2 (free 

and total)(b)

12/13/05, 01/17/06, 

02/15/06, 02/28/06, 

03/28/06, 04/25/06, 

05/23/06, 

06/20/06, 07/19/06, 

08/16/06, 09/15/06, 

10/11/06, 11/08/06

Offsite: As (total), Fe 

(total), Mn (total), SiO2, 

P, turbidity, and 

alkalinity

4 Monthly(c) Onsite: NA 02/13/07, 03/13/07, 

04/17/07, 05/09/07, 

06/05/07, 09/20/07, 

02/21/08, 04/16/08, 

05/15/08

Offsite: As (total and 

soluble)

d

, As(III), As(V), 

SiO2, and/or P

Distribution 

Water

Three LCR

Locations Within 

School

3 Monthly(d) pH, alkalinity, As, Fe, 

Mn, Pb, and Cu

Baseline and 

monthly sampling:

See Table 4-10

Backwash

Water

Backwash 

Discharge Line 

from Each Vessel

2 Monthly or 

as needed

pH, TDS, TSS,

As (total and soluble),

Fe (total and soluble),

and Mn (total and 

soluble)

NA

(a) Abbreviations in parentheses corresponding to sample locations shown in Figure 4-5.

(b) Except at IN location.

(c) Only As (total) analyzed from 09/20/07 to 05/15/08.

(d) Four baseline sampling events performed from June to September 2005 before system became operational.

LCR = Lead and Copper Rule; NA = not applicable.
9

the sampling schedule and analytes measured during each sampling event. 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).

3.3.1 Source Water Sample Collection. During the initial visit to the site on November 15, 2004, 

one set of source water samples was collected and speciated using an arsenic speciation kit (see Section 

3.4.1). The sample tap was flushed for several minutes before sampling; special care was taken to avoid 

agitation, which might cause unwanted oxidation. Analytes for the source water samples are listed in 

Table 3-3. 

3.3.2 Treatment Plant Water Sample Collection. During the system performance evaluation 

study, biweekly water samples were collected across the treatment train by the plant operator for onsite 

and offsite analyses. Except for a few exceptions, samples were collected during the first week of each 

four-week cycle at the wellhead (IN), after pH adjustment and chlorination (AP), after the lead adsorption 

vessel (TA), and after the lag adsorption vessel (TB) and analyzed for the analytes listed on Table 3-3. 

During the third week of the four-week cycle, samples were taken from the same four locations and 

analyzed for the analyte list shown on Table 3-3. Beginning on Feburary 13, 2007, samples were 

collected from the same four locations on a monthly basis and analyzed for the analytes shown on 

Table 3-3. 

3.3.3 Backwash Wastewater/Solids and Spent Media Collection. Because the system did not 

require backwash during the system performance evaluation, no backwash residuals were produced. 

Further, because media replacement did not take place, there were no spent media samples collected. 

3.3.4 Distribution System Water Sample Collection. Samples were collected from the 

distribution system by the plant operator to determine the impact of the arsenic treatment system on the 

water chemistry in the distribution system, specifically the arsenic, lead, and copper levels. From June to 

September 2005, prior to the startup of the treatment system, four baseline distribution sampling events 

were conducted at three locations within the distribution system. Following startup of the arsenic 

adsorption system, distribution system sampling continued on a monthly basis at the same three locations. 

The three locations selected were sample taps within the Webb CISD that had been included in the Lead 

and Copper Rule (LCR) sampling in the past. The baseline and monthly distribution system samples 

were collected following an instruction sheet developed according to the Lead and Copper Monitoring 

and Reporting Guidance for Public Water Systems (EPA, 2002). The date and time of last water use 

before sampling and the date and time of 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. Analytes for the baseline samples coincided with the monthly 

distribution system water samples as described in Table 3-3. Arsenic speciation was not performed for 

the distribution system water samples.

3.4 Sampling Logistics

All sampling logistics including preparation of arsenic speciation kits and sample coolers, and sample 

shipping and handling are discussed as follows: 

3.4.1 Preparation of Arsenic Speciation Kits. The arsenic field speciation method used an anion 

exchange resin column to separate the soluble arsenic species, As(V) and As(III) (Edwards et al., 1998). 

Resin columns were prepared in batches at Battelle laboratories according to the procedures detailed in 

Appendix A of the EPA-endorsed QAPP (Battelle, 2004). 
10

3.4.2 Preparation of Sampling Coolers. For each sampling event, a sample cooler was prepared 

with the appropriate number and type of sample bottles, disc filters, and/or speciation kits. All sample 

bottles were new and contained appropriate preservatives. Each sample bottle was affixed with a preprinted, color-coded, and waterproof label, consisting of the sample identification (ID), date and time of 

sample collection, collector’s name, site location, sample destination, analysis required, and preservative. 

The sample ID consisted of a two-letter code for the specific water facility, sampling date, a two-letter 

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

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

example, red, orange, yellow, and blue were used to designate sampling locations for IN, AP, TA, and 

TB, respectively. The prelabeled bottles for each sampling location were placed in separate zip-lock bags 

and packed in the cooler. 

 

When appropriate, the sample cooler was packed with bottles for the three distribution system sampling 

locations. In addition, all sampling and shipping-related materials, such as latex gloves, sampling 

instructions, chain-of-custody forms, prepaid FedEx air bills, and bubble wrap, were included. Except for 

the operator’s signature, the chain-of-custody forms and prepaid FedEx air bills had already been 

completed with the required information. The sample coolers were shipped via FedEx to the facility 

approximately 1 week prior to the scheduled sampling date. 

3.4.3 Sample Shipping and Handling. After sample collection, samples for off-site analyses were 

packed carefully in the original coolers with wet ice and shipped to Battelle. Upon receipt, 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 and TCCI Laboratories in 

Lexington, OH, both of which were under contract with Battelle for this demonstration study. The chainof-custody forms remained with the samples from the time of preparation through analysis and final 

disposition. All samples were archived by the appropriate laboratories for the respective duration of the 

required hold time and disposed of properly thereafter. 

3.5 Analytical Procedures

The analytical procedures described in detail in Section 4.0 of the EPA-endorsed QAPP (Battelle, 2004) 

were followed by Battelle ICP-MS, AAL, and TCCI Laboratories. Laboratory quality assuarnce/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 QA data associated with each analyte will be presented and evaluated in a QA/QC Summary 

Report to be prepared under separate cover upon completion of the Arsenic Demonstration Project. 

Field measurements of pH, temperature, DO, and ORP were conducted by the plant operator using a 

VWR Symphony SP90M5 Handheld Multimeter, which was calibrated for pH and DO prior to use 

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

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

collected a water sample in a clean, plastic beaker and placed the Symphony SP90M5 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.
11

4.0 RESULTS AND DISCUSSION

4.1 Facility Description and Pre-existing Treatment System Infrastructure

Located at 619 Avenue F in Bruni, Texas, the Webb CISD water system supplies water to approximately 

230 students and staff members during the academic year. Figure 4-1 shows the pre-existing water 

treatment facility. The water system was served by a single well that is 7-in in diameter and 

approximately 345 ft deep. The supply well, shown in Figure 4-2, was equipped with a 5-horsepower 

(hp), 15-in submersible pump rated for 40 gpm at 300 ft H2O or 130 lb/in2

 (psi). The pre-existing system

typically operated for 6 to 8 hr/day, with an average daily demand of 10,000 gpd and an estimated peak 

daily demand of 15,000 gpd. The pre-existing treatment included only chlorination with a 10% sodium 

hypochlorite (NaOCl) solution to reach a target residual level of 1.2 mg/L (as Cl2). Figure 4-3 shows the 

chlorine addition system at the site. Following chlorination, the treated water was stored in a 15,000-gal 

storage tank located in a fenced area in the immediate vicinity of the well and chlorine addition system. 

Figure 4-1. Pre-existing Water Treatment Facility 

(from Left to Right: Wellhead in front of White Storage Shed, Chlorine Addition 

System in Black Rectangular Box, and White Storage Tank for Treated Water)

4.1.1 Source Water Quality. Source water samples were collected and speciated on November 

15, 2004, for onsite and offsite analyses. The results are presented in Table 4-1 and compared to those 

taken by the facility for the EPA demonstration site selection.

Arsenic. Total arsenic concentrations of source water ranged from 55.6 to 59 μg/L. Based on Battelle’s 

speciation results, out of 55.2 μg/L of soluble arsenic, 19.6 μg/L existed as As(V) and 35.6 μg/L as 

As(III). Therefore, pre-oxidation of As(III) to As(V) prior to adsorption was required. 
12

Figure 4-2. Wellhead at Webb CISD

Figure 4-3. Pre-existing Chlorine Addition System
13

Table 4-1. Water Quality Data for Webb CISD, Bruni, TX

Parameter Unit

Raw Water Treated Water

Facility 

Data(a)

Battelle 

Data

TCEQ

Data

Date - 11/15/04 01/12/98–10/26/04

pH S.U. 8.1 8.0 6.8–8.2

Temperature °C NA 25.3 NA

DO mg/L NA 1.5 NA

ORP mV NA -122 NA

Total Alkalinity (as CaCO3) mg/L 323 325 232–297

Hardness (as CaCO3) mg/L 24.0 23.5 25.0–27.2

Turbidity NTU NA 0.7 NA

TDS mg/L NA 1,060 781–795

TOC mg/L NA 0.9 NA

Nitrate (as N) mg/L NA <0.04 0.3–1.2

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

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

Chloride mg/L 188 130 180–229

Fluoride mg/L NA 1.0 0.7–0.8

Sulfate mg/L 104 98.0 97.4–113

Silica (as SiO2) mg/L NA 42.3 NA

Orthophosphate (as PO4) mg/L NA <0.06 NA

As(total) μg/L 59.0 55.6 75.9–104

As (soluble) μg/L NA 55.2 NA

As (particulate) μg/L NA 0.4 NA

As(III) μg/L NA 35.6 NA

As(V) μg/L NA 19.6 NA

Fe (total) μg/L 27 <25 10–51

Fe (soluble) μg/L NA <25 NA

Mn (total) μg/L 8 4.5 1–8

Mn (soluble) μg/L NA 4.3 NA

U (total) pCi/L NA 10.6 <25

U (soluble) pCi/L NA 10.2 NA

V (total) μg/L NA 4.4 NA

V (soluble) μg/L NA 4.4 NA

Na (total) mg/L 301 333 272–293

Ca (total) mg/L 7 6.1 7.1–8.0

Mg (total) mg/L 2 2.0 1.0–2.3

(a) Provided by facility to EPA for demonstration site selection.

TCEQ = Texas Commission on Environmental Quality

NA = not analyzed

Iron. Iron concentrations in source water were low, typically less than its detection limit of 25 μg/L. In 

general, adsorptive media technologies are best suited to sites with relatively low iron levels (e.g., less 

than 300 μg/L of iron, which is the secondary maximum contaminant level [SMCL] for iron). With 

concentrations greater than 300 μg/L, taste, odor, and color problems can occur in the treated water, along 

with an increased potential for fouling of the adsorption system components with iron particulates.

pH. pH values of raw water were between 8.0 and 8.1. At pH values greater than 8.0 to 8.5, the AM 

vendor recommends that the pH values be lowered to enhance the adsorptive capacity of the media. The 
14

treatment process for the Webb CISD site included a CO2 injection and pH monitoring and control 

module prior to arsenic adsorption. The target pH level after pH adjustment was 7.0. 

Competing Anions. Arsenic adsorption can be influenced by the presence of competing anions such as 

silica and phosphate. Analysis of source water indicated silica levels at 42.3 mg/L and orthophosphate 

levels less than its detection limit (i.e., <0.06 mg/L). The effect of silica on arsenic adsorption was

monitored closely during the demonstration study. 

Other Water Quality Parameters. Other water quality parameters in source water were below their 

respective primary MCLs, including nitrate, nitrite, and ammonia. Also, chloride, fluoride, sulfate, and 

manganese were below their respective SMCLs. Total dissolved solids (TDS) were measured at 1,060 

mg/L, which is above the SMCL of 500 mg/L.

4.1.2 Treated Water Quality. In addition to the source water quality data, Table 4-1 also presents 

historic treated water quality data collected by TCEQ from January 1998 through October 2004. These 

treated water quality data were similar to the source water quality data provided by the facility and 

collected by Battelle. Total arsenic concentrations of the treated water were slightly higher and ranged 

from 75.9 to 104 μg/L. No arsenic speciation data were available for the water following chlorination. 

pH values ranged from 6.8 to 8.2. Additional analytes including several metals and radionuclides are 

summarized in Table 4-2. 

Table 4-2. TCEQ Treated Water Quality Data 

Parameter Unit TCEQ Data

Date 01/12/98–10/26/04

Antimony μg/L 1–4

Barium μg/L 39.7–40

Beryllium μg/L <1

Cadmium μg/L 0.2–1.2

Chromium μg/L <10

Copper μg/L 2.2–7.7

Lead μg/L 1–12

Mercury μg/L <0.4

Nickel μg/L 1–20

Selenium μg/L 8.5–12.7

Silver μg/L 1–10

Thallium μg/L <1

Zinc μg/L <4–20

Gross Alpha pCi/L 26.2–28.3(a)

Gross Beta pCi/L 11.8–12.5

Radium 226 pCi/L <1

Tritium pCi/L 500

(a) over 15 pCi/L MCL

4.1.3 Distribution System. The distribution system was constructed primarily of polyvinyl 

chloride (PVC) piping and some galvanized piping. The piping within the building was copper. The 

distribution system was supplied directly from the 15,000-gal storage tank. The three locations selected 

for distribution sampling included one location each in the middle school, high school, and cafeteria. 

These locations represented the distribution system sampling and also were part of the school’s historic 
15

LCR sampling network. The school also sampled for coliform once a month and volatile organic 

compounds (VOCs), inorganics, nitrate, and radionuclides as directed by the TCEQ, typically once every 

two to three years. 

4.2 Treatment Process Description

The AdEdge arsenic package unit (APU) is a fixed-bed, down-flow adsorption system used for small 

water systems in the flow range of 5 to 100 gpm. The system uses Bayoxide E33 media (branded as AD33 by AdEdge), an iron-based adsorptive media developed by Bayer AG, for the removal of arsenic from 

drinking water supplies. Table 4-3 presents physical and chemical properties of the media. AD-33 media 

is delivered in a dry crystalline form and listed by NSF International (NSF) under Standard 61 for use in 

drinking water applications. The media exist in both granular and pelletized forms, which have similar 

physical and chemical properties, except that pellets are denser than granules (i.e., 35 lb/ft3

 vs. 28 lb/ft3). 

For the Webb CISD site, pellets were selected for use.

Table 4-3. Physical and Chemical Properties of AD-33 Media(a)

Physical Properties

Parameter Value

Matrix Iron oxide composite

Physical form Dry pellets

Color Amber

Bulk Density (lb/ft3) 35

BET Area (m2/g) 142

Attrition (%) 0.3

Moisture Content (%) <15 (by weight)

Particle size distribution (U.S. Standard mesh) 10 × 35 

Crystal Size (Å) 70

Crystal Phase α – FeOOH

Chemical Analysis

Constituents Weight (%)

FeOOH 90.1

CaO 0.27

MgO 1.00

MnO 0.11

SO3 0.13

Na2O 0.12

TiO2 0.11

SiO2 0.06

Al2O3 0.05

P2O5 0.02

Cl 0.01

(a) Provided by AdEdge

BET = Brunauer, Emmett, and Teller

For series operation, when the media in the lead vessel completely exhausts its capacity and/or when the 

effluent from the lag vessel reaches 10 μg/L of arsenic, the spent media in the lead vessel is removed and 

disposed of as a non-hazardous waste if it passes the Toxicity Characteristic Leaching Procedure (TCLP) 

test. The media life depends upon the arsenic concentration, the empty bed contact time (EBCT), the 

mode or variability of operation (on/off), pH, and concentrations of competing ions in source water. 
16

After rebedding, the lead vessel is switched to the lag position and the lag vessel is switched to the lead 

position. In general, the series operation better utilizes the media capacity when compared to the parallel 

operation because the media in the lead vessel may be allowed to exhaust completely prior to change-out. 

During the system performance evaluation, the need for media replacement was never required. At the 

end of the performance evaluation study, the arsenic concentrations in the lead and lag vessels were 45.4 

μg/L and 5.2 μg/L, respectively. 

The arsenic treatment system at the Webb CISD site (specifically referred to as the APU-50LL-CS-S-2-

AVH system) consisted of two vessels (i.e., A and B), operating in series. The piping and valve 

configuration of the pressure vessels allowed electrically actuated butterfly valves to divert raw water 

flow into either Vessel A or Vessel B depending on which was operating as the lead vessel. A simplified 

process flow diagram of the treatment system is shown in Figure 4-4. The system was located in the 

maintenance building, which provided sufficient space available to house the system. Figure 4-5 is a 

generalized process flow sampling diagram of the system that illustrates sampling locations and 

parameters analyzed during the demonstration study. Table 4-4 presents key system design parameters.

The key process steps and major components of the water treatment system include:

• Intake. Raw water was pumped from the supply well and fed to the treatment system. 

• pH adjustment. pH values of raw water were lowered to a target pH value of 7.0 using CO2, 

which was selected for pH adjustment because 1) CO2 is less corrosive than mineral acids, 

such as H2SO4, and 2) when the treated water depressurized after exiting the adsorption 

vessels, some CO2 may degas, thereby raising pH values of the treated water and reducing its 

corrosivity to the distribution piping. 

A Carbon Dioxide Gas Flow Control System manufactured by Applied Technology Systems, 

Inc. (ATSI) in Souderton, PA was used for pH adjustment. Figure 4-6 presents a process 

diagram of the system, which was designed to introduce gaseous CO2 into water in a sidestream configuration, or a CO2 loop. The system, illustrated in Figure 4-7 as a composite of 

photographs, consisted of a liquid CO2 supply assembly, an automatic pH control panel, a 

CO2 membrane assembly, and a pH probe located downstream of the membrane module: 

o Liquid CO2 in two 50-lb cylinders vaporized into gaseous CO2 via a feed vaporizer prior 

to entering the pH control panel. 

o As the CO2 gas flowed to the pH control panel, the gas flowrate was automatically 

controlled and adjusted by a JUMO pH/Proportional Integral Derivative (PID) controller 

and an Alicat mass flowmeter (Figure 4-6) to reach a desired pH setpoint. As an 

alternative, manual regulation of the gas flowrate could also be achieved via the use of a 

three-way ball valve and a rotameter. Further, a solenoid valve interlocked with the well 

pump allowed gas to flow only when the well pump was turned on. 

o After flowing out of the control panel, CO2 was injected into water through a Celgard®

microporous hollow fiber membrane module housed in a 1.5-in stainless steel sanitary 

cross. Table 4-5 lists the properties and specifications of the hollow fiber membrane 

module. The sanitary cross was located in a side stream from the main water line to 

allow only a portion of water to flow through the membrane module to minimize the 

pressure drop. The membrane introduced CO2 gas into the water at a near molecular 

level for rapid mixing/reaction with water to achieve a quick pH response/change. 
17

Figure 4-4. Process Flow Diagram for APU-50LL-CS-S-2-AVH System
18

Figure 4-5. Process Flow Diagram and Sampling Schedules and Locations

LEGEND

LEGEND

Influent

After pH Adjustment

and Chlorination

Vessel A Effluent

DA: Cl2

INFLUENT

Chlorine Disinfection

Unit Process

Process Flow

Backwash Flow

AP

SS

BW

Water Sampling Locations

IN

TB

TA

Vessel B Effluent

Backwash Sampling Location

Sludge Sampling Location

pH(a), temperature(a), DO/ORP(a), 

Cl2 (free and total), As, Fe, Mn, 

SiO2, P, turbidity, alkalinity

BACKWASH

STORAGE

TANK

(12,000 GAL)

INFLUENT

pH ADJUSTMENT –

CO2 INJECTION

Bruni, TX

AD33® Technology

Design Flow: 40 gpm

DISTRIBUTION 

SYSTEM

DA: Cl2

Footnote

(a) On-site analyses

BW

IN

AP

pH, TDS, TSS,

As (total and soluble),

Fe (total and soluble),

Mn (total and soluble) TA

TB

pH(a), temperature(a),

DO/ORP(a), Cl2 (free and total),

As (total and soluble), As (III),

As (V), Fe (total and soluble),

Mn (total and soluble), Ca, Mg,

F, NO3, SO4, SiO2, P,

turbidity, alkalinity

pH(a), temperature(a), 

DO/ORP(a), As (total and 

soluble), As (III), As (V),

Fe (total and soluble),

Mn (total and soluble),

Ca, Mg, F, NO3, SO4, SiO2, P, 

turbidity, alkalinity

pH(a), temperature(a), DO/ORP(a), 

Cl2 (free and total), As, Fe, Mn, 

SiO2, P, turbidity, alkalinity

pH(a), temperature(a), 

DO/ORP(a), As, Fe, Mn,

SiO2, P, turbidity, alkalinity

pH(a), temperature(a),

DO/ORP(a), Cl2 (free and total),

As (total and soluble), As (III),

As (V), Fe (total and soluble),

Mn (total and soluble), Ca, Mg,

F, NO3, SO4, SiO2, P,

turbidity, alkalinity

MEDIA 

VESSEL 

B

MEDIA 

VESSEL 

A

pH(a), temperature(a), DO/ORP(a), 

Cl2 (free and total), As, Fe, Mn, 

SiO2, P, turbidity, alkalinity

pH(a), temperature(a),

DO/ORP(a), Cl2 (free and total),

As (total and soluble), As (III),

As (V), Fe (total and soluble),

Mn (total and soluble), Ca, Mg,

F, NO3, SO4, SiO2, P,

turbidity, alkalinity

STORAGE TANK

(15,000 GAL)

SS TCLP

TO SEWER/

ON-SITE

TREATMENT

AND DISPOSAL

1st Week of 4-week Cycle

3rd Week of 4-week Cycle
19

Table 4-4. Design Specifications for AdEdge APU-50LL-CS-S-2-AVH System

Parameter Value Remarks

Pre-treatment

Target pH Value after Adjustment (S.U.) 7.0 Using CO2

Target Chlorine Residual (as Cl2) 1.2 Using NaClO

Adsorption Vessels

Vessel Size (in) 42 D × 72 H –

Cross-Sectional Area (ft2/vessel) 9.6 –

Number of Vessels 2 –

Configuration Series –

AD-33 Adsorption Media

Media Bed Depth (in) 27.5

Media Quantity (lb) 1,540 770 lb/vessel

Media Volume (ft3) 44 22 ft3/vessel

Media Type AD-33 In pelletized form 

Service

Design Flowrate (gpm) 40 –

Hydraulic Loading Rate (gpm/ft2) 4.2 –

EBCT (min/vessel) 4.1 Based on flowrate of 40 gpm per vessel (8.2 

min total EBCT for both lead and lag vessels) 

Estimated Working Capacity (BV) 46,900 Bed volumes to 10 μg/L total arsenic

breakthrough from lag vessel based on vendor 

estimate

Throughput to Breakthrough (gal) 7,725,000 1 BV = 22 ft3 = 164 gal

Average Use Rate (gal/day) 12,000 Based on 5 hr/day operation at 40 gpm

Estimated Media Life (months) 21.5 Estimated frequency of media change-out from 

lead vessel based on 12,000 gal/day use rate

Backwash

Pressure Differential Set Point (psi) 10 –

Backwash Flowrate (gpm) 90 –

Hydraulic Loading Rate (gpm/ft2) 9.4 –

Backwash Frequency (month/backwash) 3–4 Actual backwash frequency to be determined

Backwash Duration (min/vessel) 20 –

Service-to-Waste Fast Rinse Flowrate (gpm) 90 –

Fast Rinse Duration (min/vessel) 1–4 –

Wastewater Production (gal/vessel) 1,890–2,160 –

o Located downstream from the sanitary cross, a Sentron Ion Sensitive Field Effect 

Transistor (ISFET) type silicon chip sanitary pH probe with automatic temperature 

compensation continuously monitored pH levels of the treated water and sent signals 

back to the pH/PID controller for pH control. 

o Throughout the study, the CO2 pH control system supplied CO2 at approximately 14.2 

ft3

/hr, using about 6.6 lb/day (based on a gas density of 0.117 lb/ft3 and an average

operating time of 4.0 hr/day). The CO2 gas supplied from two 50-lb cylinders provided 

CO2 for about 7.5 days before requiring change-out. 
20

Figure 4-6. Process Diagram of CO2 pH Adjustment System (top) and pH/PID 

Control Panel (bottom) 

Source: Applied Technology Systems, Inc. (ATSI)
21 

 

Figure 4-7. Carbon Dioxide Gas Flow Control System for pH Adjustment

(Clockwise from Top Left: Liquid CO2 Supply Assembly; 

Automatic pH Control Panel; CO2 Membrane Module; Port for pH Probe) 

Table 4-5. Properties of Celgard®, X50-215 Microporous 

Hollow Fiber Membrane 

Parameter Value

Porosity (%) 40

Pore Dimensions (μm) 0.04 × 0.10 

Effective Pore Size (μm) 0.04 

Minimum Burst Strength (psi) 400

Tensile Break Strength (g/filament) ≥300

Average Resistance to Air Flow (Gurley sec) 50 

Axial Direction Shrinkage (%) ≤5

Fiber Internal Diameter, nominal (μm) 220

Fiber Wall Thickness, nominal (μm) 40

Fiber Outer Diameter, nominal (μm) 300

Module Dimensions (in) 1.5 × 3.0 

Data Source: Celgard®
22 

• Prechlorination. The existing chlorination system, as shown in Figure 4-3, was upgraded 

and installed inside the maintenance building along with the APU-50LL-CS-S-2-AVH

system. Chlorine oxidizes As(III) to As(V) prior to the adsorption vessels and provides a 

target residual of 1.2 mg/L (as Cl2) for disinfection in the distribution system. The chlorine 

feed system, illustrated in Figure 4-8, included a solenoid-driven, diaphragm-type metering 

pump with a capacity range of 0.19 to 8.4 gal/hr (gph), a 50-gal high-density polyethylene 

(HDPE) chemical feed tank to store the 10% NaClO solution, and a chlorine injection port. 

Chlorine was injected into the raw water line following the CO2 injection and pH probe, but 

prior to the AP sampling location. Operation of the chlorine feed system was linked to the 

well pump so that chlorine was injected only when the well was on. Chlorine consumption 

was measured using volumetric markings on the outside of the feed tank.

 

Figure 4-8. Chlorination Feed System

(Clockwise from Top Left: Chlorine Metering Pump; 

HDPE Chemical Feed Tank with Secondary Containment; Chlorine Injection Port) 

• Adsorption. The AdEdge APU-50LL-CS-S-2-AVH system consisted of two 42-in × 72-in 

pressure vessels configured in series, each containing 22 ft3 of AD-33 media. The vessels 

were carbon steel construction, skid mounted, and rated for 100-psi working pressure. EBCT 

for the system was 4.1 min in each vessel. The hydraulic loading rate to each vessel was

approximately 4.2 gpm/ft2

, based on the design flowrate of 40 gpm. 

Each pressure vessel was interconnected with schedule 80 PVC piping and five electrically 

actuated butterfly valves, which make up the valve tree shown in Figure 4-9. In addition to 

the 10 butterfly valves, the system had two manual diaphragm valves on the backwash line 
23 

and six isolation ball valves to divert raw water flow into either vessel, which reversed the 

lead/lag vessel configuration. Each valve operated independently and the butterfly valves 

were controlled by a Square D Telemechanique programmable logic controller (PLC) with a 

Magelis G2220 color touch interface screen.

Figure 4-9. Adsorption System Valve Tree and Piping Configuration

• Backwash. The vendor recommended that the APU-50LL-CS-S-2-AVH system be 

backwashed, either manually or automatically, on a regular basis to remove particulates and 

media fines that accumulate in the media beds. Automatic backwash can be initiated by 

either timer or Δp across the vessels. During the backwash cycle, each vessel is backwashed 

individually, while the second vessel remains off-line. Backwash is performed upflow at a

flowrate of 90 gpm to achieve a hydraulic loading rate of about 9.3 gpm/ft2

. Because the 

incoming flowrate from the supply well is insufficient to provide the necessary flow for 

backwash, supplemental water is supplied from the treated water storage tank to the head of 

the system. Each backwash cycle is set to last for about 20 min/vessel of backwash followed 

by 1 to 4 min/vessel of service-to-waste fast rinse, generating a combined total of

approximately 1,890 to 2,160 gal/vessel of wastewater. 

The backwash water produced is pumped to a 12,000-gal fiberglass backwash storage tank

located adjacent to the treated water storage tank (see Figure 4-1). Water from the backwash

storage tank is sent to an onsite wastewater plant and then to a series of four stabilization 

ponds, which provide approximately 120 days of storage capacity. If the storage capacity of 

the stabilization ponds is exceeded, the discharge goes to a normally dry streambed, where it 

ultimately evaporates or percolates into the ground. 
24 

Due to minimal pressure drop across the vessels throughout the study, system backwash was 

not performed throughout the performance evaluation study. The pressure drop and the 

arsenic concentrations across the vessels were monitored regularly.

• Media Replacement. Based on the analytical results from the final sampling event, total 

arsenic concentrations in the treated water were 45.4 and 5.2 μg/L following Tanks A and B, 

respectively. The total arsenic concentration from the lag vessel did not exceed the MCL of 

10 μg/L; therefore, the media in the lead vessel was not replaced during the study period. 

Based on the estimate provided by the vendor, breakthrough of arsenic was expected after 

about 46,900 BV of water treated or about 21.5 months of system operation, assuming an 

average use rate of 5 hr/day operation at 40 gpm. 

4.3 System Installation 

The installation of the APU system was completed by AdEdge on November 19, 2005. The following 

briefly summarizes some of the predemonstration activities, including permitting, building preparation, 

and system offloading, installation, shakedown, and startup. 

4.3.1 Permitting. An exception submittal package was submitted to TCEQ by Webb CISD on 

April 18, 2005, requesting an exception to use data from an alternative site in lieu of conducting an onsite 

pilot study as required under Title 30 Texas Administrative Code (30 TAC) §290.42(g). The exception 

submittal included a written description of the treatment technology along with a schematic of the system 

and relevant pilot- and full-scale data. In addition, a permit application submittal package including a 

process flow diagram of the treatment system, mechanical drawings of the treatment equipment, and a 

schematic of the building footprint and equipment layout also was submitted to TCEQ for permit 

approval on April 18, 2005. TCEQ requested supplemental information, in a response letter dated June 3, 

2005, to complete its review of the request. In response, supplementary data were provided by the vendor 

on July 14, 2005, Battelle on August 22, 2005, and Southwest Engineers, Inc. on August 29, 2005. Based 

on a review of the submitted data (which included revised engineering plans and specifications, dated 

August 19, 2005) and discussions with the vendor, Battelle, and EPA, TCEQ granted an exception request 

and approval to construct the arsenic removal treatment system on August 31, 2005. 

4.3.2 Building Preparation. The existing maintenance shop building as shown in Figure 4-10 had 

adequate space to house the planned arsenic treatment system. The maintenance building is a single-story 

metal structure with concrete flooring. Additional preparation required the installation of a lockable wire 

cage enclosure around the treatment system.

4.3.3 Installation, Shakedown, and Startup. The treatment system arrived onsite on October 13, 

2005. Figure 4-11 shows a photograph of the system arriving at the site. AdEdge and ATSI were onsite 

for the system installation during the week of November 14, 2005. ATSI performed the installation and 

shakedown of the carbon dioxide gas flow control system for pH adjustment. Meanwhile, AdEdge and 

the local operator performed the arsenic treatment system installation and shakedown work, which 

included hydraulic testing, media loading (by hand), and media backwash. The system officially went 

online and was put into regular service on December 7, 2005. Battelle was onsite on December 8 and 9, 

2005, to inspect the system and provide training to the operator for sampling and data collection. As a

result of the system inspections, a punch-list of items was identified, some of which were quickly 

resolved and did not affect system operations or data collection, although several problems related to the 

pH adjustment system and the media vessel flow meters surfaced throughout the system performance 

evaluation. Table 4-6 summarizes the items identified and corrective actions taken. In addition, these 

problems are discussed in detail in Section 4.4.3. 

 
25 

Figure 4-10. Maintenance Shop Building 

Figure 4-11. System Delivery to Site 
26 

Table 4-6. System Punch-List/Operational Issues

Item 

No.

Punch-List/ 

Operational Issues Corrective Action(s) Taken

Resolution 

Date

1 Well pump hour meter not provided • Installed hour meter for well pump 01/09/06

2 Leak in CO2 supply system • Checked and tightened all connections 

and fittings

01/11/06

3 Flow totalizer for Vessels A and B 

reset to zero 

• Vendor notified

• No corrective action taken 

01/12/06

4 Inline pH probe reporting pH >8 • Flushed pH probe by-pass line and 

increased flowrate through by-pass line

03/13/06

5 Malfunctioning proportioning valve 

restricted CO2 injection

• Replaced proportioning valve 04/24/06

6 Inline pH probe not reporting pH 

reading

• Replaced pH probe 05/30/06

02/22/06

7 Flow totalizer for Vessels A and B 

reset to zero

• Vendor notified

• Problem due to a programming error; a 

flash memory card with necessary 

programming updates provided by 

vendor

05/23/06

06/15/06

TBD = to be determined 

4.4 System Operation

4.4.1 Operational Parameters. The operational parameters for the system performance 

evaluation were tabulated and are attached as Appendix A. Key parameters are summarized in Table 4-7. 

From December 8, 2005, through May 15, 2008, the system operated for a total of 3,725 hr. Due to lack 

of a well pump hour meter from system startup through January 9, 2006 and due to the departure of the 

Webb CISD APU system operator from June 29, 2007 through the end of the performance evaluation 

study, no daily operating time was recorded during these time intervals. (Other operational data were not 

collected either since June 29, 2007.) Because the well and the system operated for 2,246 hr in 536 days 

from January 10, 2006, through June 29, 2007 (or 4.19 hr/day), the total operating time throughout the 

entire study period was estimated by multiplying the daily average of 4.19 hr/day by the total number of 

days, i.e., 889 days. 

Due to the fact that the system supplied water to Webb CISD (a school), the daily operation times and 

throughput values during the weekends and summer breaks were anticipated to be low. However, 

investigation of time and throughput during these times did not reveal reductions. On the contrary, daily 

operating time and throughput measurements increased significantly during the summer months. 

Increased time and throughput during the summer months were caused by summer irrigation. 

From December 8, 2005, through June 29, 2007, the amount of water treated by the system was 5,658,728 

gal (or 9,945 gals/day). The system ran for 889 days during the performance evaluation study; the 

estimated throughput through May 15, 2008 was 8,841,000 gal, or 27,000 BV (1 BV = 44 ft3 of media in 

both lead and lag vessels). 
27 

Table 4-7. Summary of APU-50LL-CS-S-2-AVH System Operation

Operational Parameter Actual Estimated

Duration 12/08/05–06/29/09 12/08/05–05/15/08

Cumulative Operating Time (hr) 2,246(a) 3,725

Average Daily Operating Time (hr) 4.19 4.19

Throughput (gal) 5,658,728 8,841,100

Throughput (BV)(b) 17,200 27,000

Average (Range) of Calculated Flowrate (gpm) Vessel A 

40.4 (5–92)(a,c)

Vessel B 

40.0 (6–88)(a,c)

–

Average (Range) of EBCT per Vessel (min)(d) Vessel A 

4.1 (1.8–32.9)

Vessel B 

4.1 (1.9–27.4)

–

Average (Range) of EBCT for System (min) 8.2 –

Average (Range) of System Inlet Pressure (psi) 42.0 (32–64) NA

Average (Range) of System Outlet Pressure (psi) 28.6 (16–54) NA

Average (Range) of ∆p across System (psi) 13.9 (2–22) NA

Average (Range) of ∆p across Vessel A (psi) 5.7 (1–9) NA

Average (Range) of ∆p across Vessel B (psi) 5.3 (0–8) NA

(a) From January 10, 2006, through June 29, 2007.

(b) Calculated based on 44 ft3 of media in one vessel. 

(c) Not including two outliers on January 29 and 30, 2007.

(d) Calculated based on 22 ft3 of media in one vessel. 

Flowrates of the system were tracked by instantaneous flowrate readings from the electromagnetic flow 

meter/totalizer on each adsorption vessel, and calculated flowrate values based on hour meter and flow 

totalizer readings from the same electromagnetic flow meters/totalizers and a pre-existing positive 

displacement type master totalizer installed at the wellhead. As shown in Figure 4-12, the instantaneous 

readings for Vessels A and B, denoted by “■” and “▲,” respectively, were significantly higher than the 

corresponding calculated values, denoted by “□” and “Δ,” respectively, with an average value of 51 gpm 

for the instantaneous readings and 42 gpm for the calculated values. In addition, the calculated values 

based on the electromagnetic flow meters/totalizers were significantly higher than those based on the 

master totalizer (denoted by “♦” in the figure). Although the results produced by the master totalizer were 

closer to the design flowrate of 40 gpm, the calculated values by the electromagnetic flow meters/ 

totalizers were used as system flowrates. This was based on the belief that readings from the 

factory-calibrated electromagnetic flow meters/totalizers were more reliable than those from the master 

totalizer, for which little information was available regarding its accuracy and installation specifications. 

Therefore, for performance evaluation purposes, the data produced by the electromagnetic flow 

meter/totalizer on the lag vessel were used to determine system flowrates and total volume treated.

Figure 4-12 also identifies flowrate data that were not consistent with normal operations and caused by an 

unintentional resetting of the electromagnetic flow meters/totalizers on two separate occasions. Detailed 

discussions regarding the resetting of the totalizers are provided in Section 4.4.3. 
28 

0

10

20

30

40

50

60

70

80

90

100

01/09/06 03/25/06 06/08/06 08/22/06 11/05/06 01/19/07 04/04/07 06/18/07

Flowrate (gpm)

Totalizer Average Flowrate

Vessel A (Lead) Instantaneous Flowrate

Vessel A (Lead) Average Flowrate

Vessel B (Lag) Instantaneous Flowrate

Vessel B (Lag) Average Flowrate

Figure 4-12. System Instantaneous and Calculated Flowrates

At the end of the study, the system treated approximately 8,841,000 gal of water. The amount of water 

treated was equivalent to approximately 27,000 BV based on the 44 ft3 of media in both lead and lag 

vessels. Calculated flowrates through Vessels A and B averaged 40.4 and 40.0 gpm, respectively, which 

was very close to the design value (Table 4-4) derived from the 40-gpm supply well flowrate based on the 

pump curve provided by the facility. Based on the average calculated flowrate to the vessels, the EBCT 

was 4.1 min per vessel. Due to the fluctuating flowrates observed, the EBCTs varied for the lead and lag 

vessels from 1.8 and 32.9 min and from 1.9 to 27.4 min, respectively.

 

The APU system pressure readings were monitored at the system inlet and outlet and between the lead 

and lag vessels. Average Δp readings across the treatment train, lead vessel, and lag vessel for the first 

month of system operation were 10, 3, and 4 psi, respectively. On June 29, 2007, average Δp readings 

across the treatment train, lead vessel, and lag vessel were 12, 9, and 6 psi, respectively. As such, 

minimal pressure increase was observed after 2,384 hr of system operation or after treating 5,658,726 gal 

of water. As a result, no media backwash was performed during the system performance evaluation. 

Figure 4-13a presents the system operational pressures, inlet, outlet, and differential. Figure 4-13b 

presents Vessel A operational pressures, inlet, outlet, and differential. Figure 4-13c presents Vessel B 

operational pressures, inlet, outlet, and differential. 
29 

Operational System Pressure at Bruni, TX Arsenic Demonstration Site

0

10

20

30

40

50

60

70

12/08/05 02/26/06 05/17/06 08/05/06 10/24/06 01/12/07 04/02/07 06/21/07

Pressure (psi)

System Inlet Pressure System Outlet Pressure System Differential Pressure (calculated)

Figure 4-13a. System Operational Pressure Readings

Vessel A Pressure at Bruni, TX Arsenic Demonstration Site

0

10

20

30

40

50

60

70

12/08/05 02/26/06 05/17/06 08/05/06 10/24/06 01/12/07 04/02/07 06/21/07

Pressure (psi)

Vessel A (Lead) Inlet Pressure Vessel A (Lead) Outlet Pressure Vessel A (Lead) Differential Pressure (reading)

Figure 4-13b. Vessel A Operational Pressure Readings 
30 

Vessel B Pressure at Bruni, TX Arsenic Demonstration Site

0

10

20

30

40

50

60

70

12/08/05 02/26/06 05/17/06 08/05/06 10/24/06 01/12/07 04/02/07 06/21/07

Pressure (psi)

Vessel B (Lag) Inlet Pressure Vessel B (Lag) Outlet Pressure Vessel B (Lag) Differential Pressure (reading)

Figure 4-13c. Vessel B Operational Pressure Readings

4.4.2 Residual Management. No residuals were produced because neither backwash nor media 

replacement was required during the evaluation period. 

4.4.3 System/Operation Reliability and Simplicity. Operational irregularities experienced during 

the demonstration study were related to the pH adjustment system and the adsorption vessel flow 

meters/totalizers. 

As described in Section 4.2, pH adjustment using a CO2 gas flow control system was a process 

component. On January 11, 2006, leaks were detected in the CO2 system, resulting in an additional 

change-out of a CO2 gas cylinder during the sixth week of system operations. The leaks were tracked to 

the supply line where loose fittings were discovered. During the week of March 13, 2006 (the 15th week 

of operation), the proportional flow control valve that regulated the CO2 injection rate began operating 

improperly. The failure caused pH levels after pH adjustment to remain higher than desired, as indicated 

by the inline probe readings, which averaged 7.8 during that week of operation. The pH control system 

was switched from the automatic to manual mode until the control valve was replaced on April 24, 2006. 

On May 3, 2006, the digital screen on the JUMO pH/PID controller was not displaying the pH 

measurement. A replacement inline pH probe was installed on May 30, 2006, which restored the digital 

display on the JUMO pH/PID controller. The CO2 system failed to consistently adjust pH values to the 

target value of 7.0, with the values varying between 6.5 and 8.2. Following the replacement of the faulty 

inline pH probe on May 30, 2006, the average pH was 7.2. 

On two separate occasions on January 12, 2006, and May 23, 2006, both electromagnetic flow 

meters/totalizers malfunctioned, causing the meters to reset and begin totalizing from zero. The failure 

was thought to have been caused by a programming error. After being contacted, the vendor provided a 
31 

flash memory card with the necessary programming updates, which was integrated by the operator on 

June 15, 2006, to prevent future reoccurrences of the problems.

The system O&M and operator skill requirements are discussed below in relation to pre- and posttreatment requirements, levels of system automation, operator skill requirements, preventive maintenance 

activities, and frequency of chemical/media handling and inventory requirements.

Pre- and Post-Treatment Requirements. Two pre-treatment processes were required at the Webb CISD 

site, i.e., pH adjustment and prechlorination. CO2 was used to lower pH values of raw water from as high 

as 8.2 (Table 4-1) to a target value of 7.0 in order to maintain effective adsorption by the AD-33 media. 

The CO2 injection point and inline pH probe used to monitor and control the adjusted pH levels were 

installed upstream of the chlorine injection point. O&M of the pH adjustment system required routine 

system pressure checks and regular change-out of the CO2 supply bottles as pressure was depleted. The 

operator also recorded daily pH readings from the inline probe and performed calibration of the pH probe, 

as needed. The use of CO2 for pH adjustment also required safety training for and awareness by the 

operator, due to potential hazards. 

For prechlorination, the existing chlorination system was upgraded and installed inside the maintenance 

building, which housed the APU-50LL-CS-S-2-AVH system. The upgraded chlorination system, as 

discussed in Section 4.2 and shown on Figure 4-8, utilized a 10% NaOCl solution to reach a target 

residual level of 1.2 mg/L (as Cl2). The upgraded chlorination system did not require maintenance or 

skills other than those required by the previous system. The operator monitored chlorine tank levels, 

consumption rates, and residual chlorine levels. 

System Automation. The system was fitted with automated controls that would allow for the backwash 

cycle to be controlled automatically. The system also was equipped with an automated carbon dioxide 

gas flow control system, which included a liquid CO2 supply assembly, an automatic pH control panel, a 

CO2 membrane module, and an inline pH probe located downstream of the membrane module. Each 

media vessel was equipped with five electrically actuated butterfly valves, which were controlled by a 

Square D Telemechanique PLC with a Magelis G2220 color touch interface screen. Although not 

automated, the system also was equipped with six isolation ball valves to allow for reversible lead/lag 

configuration. 

The automated portion of the system did not require regular O&M; however operator awareness and an 

ability to detect unusual system measurements were necessary when troubleshooting system automation 

failures. The equipment vendor provided hands-on training and a supplemental operations manual to the 

operator. 

Operator Skill Requirements. The skill requirements to operate the system demanded a higher level of 

awareness and attention than the previous system. The system offered increased operational flexibility, 

which, in turn, required increased monitoring of system parameters. The operator’s knowledge of the 

system limitations and typical operational parameters were key to achieve system performance objectives. 

The operator was onsite typically five times a week and spent approximately 20 min each day to perform 

visual inspections and record the system operating parameters on the daily log sheets. The basis for the 

operator skills began with onsite training and a thorough review of the system operations manual; 

however, increased knowledge and invaluable system troubleshooting skills were gained through handson operational experience. 

TCEQ requires that the operator of the treatment system hold at least a Class D TCEQ waterworks 

operator license. The TCEQ public water system operator certifications are classified by Class A through 

D. Licensing eligibility requirements are based on education, experience, and related training. The 
32 

minimum requirements for a Class D license are high school graduate or GED and 20 hr of related 

training. Licensing requirements incrementally increase with each licensing level, with Class A being the 

highest requiring the most education, experience, and training.

Preventive Maintenance Activities. Preventive maintenance tasks included periodic checks of flow

meters and pressure gauges and inspection of system piping and valves. Checking the CO2 cylinders and 

supply lines for leaks and adequate pressure and calibrating the inline pH probe also were performed. 

Typically, the operator performed these duties while onsite for routine activities. 

Chemical/Media Handling and Inventory Requirements. NaOCl was used for prechlorination; the 

operator ordered chemicals as done prior to the installation of the APU-50LL-CS-S-2-AVH system. CO2 

used for pH adjustment was ordered on an as needed basis. Typically, four 50-lb cylinders were used per 

month. As the CO2 cylinders were delivered to the site by the CO2 supplier, empty cylinders were 

returned for reuse. 

4.5 System Performance

The performance of the system was evaluated based on analyses of water samples collected from raw and 

treated water and distribution system. 

4.5.1 Treatment Plant Sampling. Table 4-8 summarizes the analytical results of arsenic, iron, 

and manganese concentrations measured at the four sampling locations across the treatment train. 

Table 4-9 summarizes the results of other water quality parameters. Appendix B contains a complete set 

of analytical results through the system performance evaluation. The results of the water samples 

collected throughout the treatment plant are discussed below.

Arsenic. Treatment plant water samples were collected on 40 occasions (including three duplicate 

samples collected during three regular sampling events), with field speciation performed during 20 of the 

40 occasions at IN, AP, TA, and TB sampling locations. Figure 4-14 contains four bar charts showing the 

concentrations of particulate arsenic, soluble As(III), and soluble As(V) for each speciation event. 

Total arsenic concentrations in raw water ranged from 46.0 to 68.7 μg/L and averaged 57.6 μg/L. Soluble 

As(III) was the predominating species, ranging from 31.3 to 42.0 μg/L and averaging 37.5 μg/L. Soluble 

As(V) also was present in source water, ranging from 6.1 to 23.8 μg/L and averaging 15.0 μg/L. 

Particulate arsenic concentrations were lower, ranging from <0.1 to 12.3 μg/L and averaging 5.7 μg/L. 

The arsenic concentrations measured were consistent with those collected previously during source water 

sampling (Table 4-1). 

Chlorine effectively oxidized As(III) to As(V) prior to the adsorption vessels. After chlorination the 

average soluble As(III) and soluble As(V) concentrations were 1.2 and 51.7 μg/L, respectively. Free and 

total chlorine residuals were monitored at the AP and TB sampling locations to ensure that the target 

chlorine residual levels were properly maintained for disinfection purposes. Free chlorine levels at the 

AP location ranged from 0.4 to 2.0 mg/L (as Cl2) and averaged 0.9 mg/L (as Cl2); total chlorine levels 

ranged from 0.6 to 2.1 mg/L (as Cl2) and averaged 1.2 mg/L (as Cl2) (Table 4-9). The residual chlorine 

levels measured at the TB location were similar to those measured at the AP location, indicating little or 

no chlorine demand through the AD-33 vessels.
33 

Table 4-8. Summary of Analytical Results for Arsenic, Iron, and Manganese

Parameter

Sample 

Location Unit

Sample 

Count

Concentration Standard 

Minimum Maximum Average Deviation

As (total) IN μg/L 39 46.0 68.7 57.6 5.3

AP μg/L 40 47.4 88.4 59.2 7.1

TA μg/L 40 1.0 45.4 5.5 8.0

TB μg/L 40 0.2 16.9 2.0 2.7

As 

(soluble)

IN μg/L 20 44.6 56.5 52.5 3.3

AP μg/L 20 44.5 61.0 52.9 3.7

TA μg/L 20 0.8 7.7 -

(a) -(a)

TB μg/L 20 0.1 2.9 -

(a) -(a)

As 

(particulate)

IN μg/L 20 0.1 12.3 5.7 3.4

AP μg/L 20 1.2 14.6 6.5 3.5

TA μg/L 20 0.1 1.3 -

(a) -(a)

TB μg/L 20 0.1 1.8 -

(a) -(a)

As(III)

IN μg/L 20 31.3 42.0 37.5 3.1

AP μg/L 20 0.4 3.3 1.2 0.8

TA μg/L 20 0.2 2.9 -

(a) -(a)

TB μg/L 20 0.1 2.4 -

(a) -(a)

As(V)

IN μg/L 20 6.1 23.8 15.0 3.9

AP μg/L 20 43.3 57.7 51.7 3.5

TA μg/L 20 0.1 7.3 -

(a) -(a)

TB μg/L 20 0.1 1.6 -

(a) -(a)

Fe (total)

IN μg/L 33 <25 163 31.8 35.1

AP μg/L 33 <25 190 <25 32.7

TA μg/L 33 <25 40.3 <25 7.6

TB μg/L 33 <25 44 <25 5.5

Fe (soluble)

IN μg/L 17 <25 133.7 <25 30.7

AP μg/L 17 <25 62.2 <25 13.0

TA μg/L 17 <25 35.3 <25 6.9

TB μg/L 17 <25 28.2 <25 3.8

Mn (total)

IN μg/L 33 2.6 14.7 5.1 2.8

AP μg/L 33 2.9 13.6 4.0 1.9

TA μg/L 33 <0.1 3.2 0.5 0.7

TB μg/L 33 <0.1 5.0 0.4 1.0

Mn 

(soluble)

IN μg/L 17 2.6 14.5 4.9 2.8

AP μg/L 17 2.9 5.2 3.6 0.8

TA μg/L 17 <0.1 3.3 0.5 0.8

TB μg/L 17 <0.1 5.1 0.6 1.3

One-half of detection limit used for samples with concentrations less than detection limit for 

calculations. 

(a) Statistics not provided; see Figure 4-15 for arsenic breakthrough curves. 
34 

Table 4-9. Summary of Water Quality Parameter Sampling Results 

Parameter

Sample 

Location Unit

Sample 

Count

Concentration Standard 

Minimum Maximum Average Deviation

Alkalinity 

(as CaCO3) 

IN mg/L 33 305 357 327 14.1

AP mg/L 33 302 357 329 15.6

TA mg/L 33 275 368 326 17.6

TB mg/L 32 312 402 334 21.3

Fluoride

IN mg/L 17 0.2 1.1 0.7 0.2

AP mg/L 17 0.5 1.8 0.9 0.3

TA mg/L 17 0.4 1.5 0.8 0.3

TB mg/L 17 0.1 1.3 0.8 0.3

Sulfate

IN mg/L 17 91.0 137 110 11.2

AP mg/L 17 102 131 110 7.8

TA mg/L 17 98.0 142 114 12.5

TB mg/L 17 83.0 136 113 12.9

Nitrate

(as N)

IN mg/L 17 <0.05 <0.05 <0.05 -

AP mg/L 17 <0.05 <0.05 <0.05 -

TA mg/L 17 <0.05 <0.05 <0.05 -

TB mg/L 17 <0.05 <0.05 <0.05 -

P 

(as P)

IN μg/L 32 <10 13.7 <10 2.3

AP μg/L 32 <10 20.4 <10 3.1

TA μg/L 32 <10 <10 <10 0.0

TB μg/L 32 <10 10.8 <10 1.0

Silica 

(as SiO2) 

IN mg/L 33 39.1 43.9 41.5 1.2

AP mg/L 33 39.4 44.9 41.7 1.1

TA mg/L 33 13.5 50.6 40.3 6.2

TB mg/L 33 1.7 95.8 39.9 13.9

Turbidity

IN NTU 33 0.1 1.2 0.6 0.3

AP NTU 33 0.1 1.5 0.5 0.3

TA NTU 33 0.1 1.9 0.5 0.4

TB NTU 32 0.1 2.0 0.5 0.4

pH

IN S.U. 21 8.0 8.3 8.2 0.1

AP S.U. 21 7.1 8.1 7.4 0.3

TA S.U. 21 7.0 7.8 7.3 0.2

TB S.U. 21 7.0 7.7 7.3 0.2

Temperature

IN °C 21 21.3 27.1 25.6 1.4

AP °C 20 21.2 27.2 25.9 1.5

TA °C 20 21.4 27.5 25.7 1.7

TB °C 19 21.2 27.4 25.5 2.0

Dissolved 

Oxygen

IN mg/L 18 1.1 3.3 2.0 0.7

AP mg/L 18 1.4 4.1 2.1 0.6

TA mg/L 18 0.9 3.4 1.9 0.5

TB mg/L 18 1.3 3.5 2.0 0.5

ORP

IN mV 18 234 378 278 38.5

AP mV 18 309 679 524 83.7

TA mV 18 337 690 578 98.0

TB mV 18 312 700 588 115

Free 

Chlorine 

(as CL2) 

IN mg/L 0 - - - -

AP mg/L 20 0.4 2.0 0.9 0.4

TA mg/L 0 - - - -

TB mg/L 18 0.4 1.7 0.9 0.4
35 

Table 4-9. Summary of Water Quality Parameter Sampling Results (Continued)

Parameter

Sample 

Location Unit

Sample 

Count

Concentration Standard 

Minimum Maximum Average Deviation

Total 

Chlorine 

(as CL2) 

IN mg/L 0 - - - -

AP mg/L 19 0.6 2.1 1.2 0.4

TA mg/L 0 - - - -

TB mg/L 18 0.5 2.1 1.1 0.5

Total 

Hardness 

(as CaCO3) 

IN mg/L 17 17.1 31.6 23.9 3.9

AP mg/L 17 19.1 30.1 23.8 3.6

TA mg/L 17 11.6 33.0 23.8 5.5

TB mg/L 17 14.3 64.4 28.9 14.0

Ca 

Hardness 

(as CaCO3) 

IN mg/L 17 11.3 22.7 16.4 3.5

AP mg/L 17 11.9 22.8 16.4 3.3

TA mg/L 17 7.6 25.1 16.4 4.3

TB mg/L 17 9.9 48.3 19.9 9.9

Mg 

Hardness 

(as CaCO3) 

IN mg/L 17 5.8 9.3 7.5 0.9

AP mg/L 17 5.3 9.1 7.4 0.9

TA mg/L 17 4.0 13.4 7.4 2.2

TB mg/L 17 3.3 23.3 9.0 5.2

One-half of detection limit used for samples with concentrations less than detection limit for 

calculations. 

The total arsenic breakthrough curves shown in Figure 4-15 indicate that the lead vessel removed the 

majority of arsenic existing predominately as As(V) following chlorination. Total arsenic concentrations 

following the lead vessel reached just below 10 μg/L (i.e., 9.6 μg/L) after treating approximately 41,000 

BV of water (based on the 22 ft3 of media in the lead vessel), which represents approximately 87% of the 

working capacity projected by the vendor (Table 4-4). Afterwards, total arsenic concentrations continued 

to ramp higher and reached 45.4 μg/L by the end of the performance evaluation study. By then, the 

system had treated an estimated 8,841,000 gal of water (see discussion in Section 4.4.1), equivalent to 

27,000 BV based on the 44 ft3 of media in both lead and lag vessel. At this point, arsenic breakthrough 

following the lag vessel, based on the laboratory analysis of water samples collected on May 15, 2008, 

was 5.2 μg/L, which was still below the 10-μg/L MCL. 

Competing Anions. Phosphate and silica, which might influence arsenic adsorption, were measured at 

the four sampling locations across the treatment train through March 13, 2007. Phosphorus was not 

detected during almost all sampling events; however, on February 13, 2007, the phosphorus 

concentrations measured at IN, AP, TA and TB were 190, 214, 203, and 167 mg/, respectively. It was not 

clear why the phosphorus concentrations were significantly elevated during this sampling event and, 

therefore, were considered as outliers and removed from data analyses. Silica concentrations in raw water 

ranged from 39.1 to 43.9 mg/L and averaged 41.5 mg/L. Significant silica concentration reductions 

(96%, 85%, and 24%, respectively) were noted in TA and TB samples collected during the first three 

weeks of system operations, indicating removal by the media. Following the third week of operation the 

maximum silica concentration reduction was less than 10%. Figure 4-16 presents the silica breakthrough 

curves from the treatment train. 
36

Figure 4-14. Concentrations of Various Arsenic Species at IN, AP, TA, and TB Sampling Locations

Arsenic Species at the Wellhead (IN)

0

10

20

30

40

50

60

70

80

12/08/0501/05/0602/01/0603/14/0604/11/0605/09/0606/06/0607/11/0608/02/0608/30/0609/28/0610/31/0611/28/0612/12/0601/22/0702/13/0703/13/0704/17/0705/09/0706/05/07

Date

As Concentration (μg/L)

As (particulate) As(III) As(V)

Arsenic Species after pH Adjustment and Chlorination (AP)

0

10

20

30

40

50

60

70

80

12/08/0512/13/0501/17/06

02/28/0604/11/06

05/09/06

06/06/06

07/11/0608/02/0608/30/0609/28/0610/31/06

11/28/06

12/12/0601/22/0702/13/07

03/13/07

04/17/07

05/09/07

06/05/07

Date

As Concentration (μg/L)

As (particulate) As(III) As(V)

Arsenic Species after Vessel A (TA)

0

10

20

30

40

50

60

70

80

12/08/0501/05/0602/01/0603/14/0604/11/0605/09/0606/06/0607/11/0608/02/0608/30/0609/28/0610/31/0611/28/0612/12/0601/22/0702/13/0703/13/0704/17/0705/09/0706/05/07

Date

As Concentration (μg/L)

As (particulate) As(III) As(V)

Arsenic Species after Vessel B (TB)

0

10

20

30

40

50

60

70

80

12/08/05

01/05/06

02/01/0603/14/0604/11/0605/09/0606/06/0607/11/0608/02/0608/30/06

09/28/06

10/31/06

11/28/06

12/12/06

01/22/0702/13/07

03/13/07

04/17/07

05/09/07

06/05/07

Date

As Concentration (μg/L)

As (particulate) As(III) As(V)
37

Total As vs. Bed Volume

0

10

20

30

40

50

60

70

80

90

100

0 5 10 15 20 25 30 35 40 45 50 55

Bed Volume (103)

As Concentration μg/L

At Wellhead (IN) After pH Adjustment and Chlorination (AP)

Lead Vessel TA Lag Vessel TB

Figure 4-15. Total Arsenic Breakthrough Curves 

(Based on 22 ft3 of Media in One Vessel)

Silica vs Bed Volume

0

20

40

60

80

100

0 5 10 15 20 25 30

Bad Volume 103

Silica (mg/L)

At Wellhead (IN) After pH Adjustment and Chlorination (AP)

Lead Vessel TA Lag Vessel B

Figure 4-16. Silica (as SiO2) Breakthrough Curves 

(Based on 22 ft3

 of Media in Each Vessel)
38

Iron and Manganese. Iron and manganese were analyzed through January 22, 2007. The average total 

iron concentration in raw water was 31.8 μg/L (Table 4-8). Average total iron concentrations across the 

treatment train were below the detection limit of 25 μg/L. Total manganese levels in raw water also were 

low, ranging from 2.6 to 14.7 μg/L and averaging 5.1 μg/L. Manganese existed primarily in the soluble 

form even after chlorination. Total manganese levels were reduced to an average of 0.5 and 0.4 μg/L

following the lead and lag vessels, respectively. 

Other Water Quality Parameters. As shown in Table 4-9, pH values of raw water measured at the IN 

sample location varied from 8.0 to 8.3 and averaged 8.2. pH values, following CO2 injection for pH 

adjustment, at the AP location, varied from 7.1 to 8.1 and averaged 7.4. A pH value of 7.0 at the AP 

location prior to the adsorption media was desirable, which, in general, would result in a greater arsenic 

removal capacity. Figure 4-17 presents the pH values measured throughout the treatment train. 

On two separate occasions (January 5 and 17, 2006), the pH values as measured with a portable VWR 

Symphony handheld meter were not reduced following CO2 injection, as indicated by the third and fourth 

sets of IN (denoted by “♦”) and AP data points (denoted by “■”) shown in Figure 4-17. In contrast, the 

pH values (denoted by “●”) measured at the AP location by the inline pH probe were consistently over 

1.0 unit less than those measured at the same location by the VWR meter. pH measurements prior to and 

following these two isolated events suggest that pH values measured by the VWR meter on January 5 and 

17, 2006, most likely were the result of instrument or measurement errors.

6.0

6.5

7.0

7.5

8.0

8.5

0 5 10 15 20 25 30 35

pH

Bed Volume 103

pH vs Bed Volume

At Wellhead (IN) After pH Adjustment and Chlorination (AP)

Lead Vessel TA Lag Vessel TB

Inline pH Adjustment

CO2 Proportioning Valve Malfunctioned

CO2 system operated in manual 

mode until proportioning value 

was replaced. Inline pH probe failure.

Figure 4-17. pH Values Across Treatment Train Versus Throughput 

(Based on 22 ft3

 of Media in Each Vessel)
39

Except for the two time periods when the CO2 system was set in the manual mode prior to the 

replacement of the proportioning valve and after Vessel A had reached approximately 25,000 BV of 

throughput, pH values measured by the VWR meter were significantly lower than those measured by the 

inline pH probe, with the pH values varying from 7.2 to 7.6 and averaging 7.4 using the VWR probe, and 

varying from 6.5 to 7.6 and averaging 7.0 using the inline probe. The variations observed might be due to 

degassing of dissolved CO2 when the water samples were collected from the AP location, thus resulting in 

elevated readings measured by the portable VWR meter. An inline pH probe failure occurred early May 

2006 (Figure 4-17) and a replacement probe was installed on May 30, 2006, at approximately 12,000 BV. 

The replacement of the inline probe did not appear to have narrowed the differences between the two 

measurements.

Alkalinity, reported as CaCO3, ranged from 305 to 357 mg/L and averaged 327 mg/L in raw water. As 

expected, alkalinity after pH adjustment and adsorption remained essentially unchanged at 326 to 334 

mg/L (on average), since carbon dioxide, instead of mineral acids, was used for pH adjustment. 

The treatment plant water samples were analyzed for hardness only on speciation weeks. Total hardness, 

reported as CaCO3, ranged from 17.1 to 31.6 mg/L and averaged 23.9 mg/L in raw water. Total hardness 

existed primarily as calcium hardness. Total hardness remained unchanged at 23.8 to 28.9 mg/L, on 

average, following pH adjustment and adsorption. 

Sulfate concentrations in raw water ranged from 91.0 to 137 mg/L and averaged 110 mg/L. After pH 

adjustment and adsorption, sulfate levels remained unchanged at 113 to 114 mg/L (on average). Fluoride 

results ranged from 0.1 to 1.5 mg/L following the treatment vessels. The results indicated that the 

adsorptive media did not affect the amount of fluoride in water after treatment. 

Average DO levels ranged from 1.9 to 2.1 mg/L throughout the treatment train. ORP readings averaged 

278 mV in raw water, but increased to an average of 524 mV after chlorination. 

4.5.2 Backwash Wastewater Sampling. Backwash was not performed during the system 

performance evaluation.

4.5.3 Distribution System Water Sampling. Prior to the installation/operation of the treatment 

system, baseline distribution system water samples were collected from the middle school, high school, 

and cafeteria on June 15, July 21, August 24, and September 19, 2005. Following the installation of the 

treatment system, distribution system water sampling continued on a monthly basis at the same three 

locations, with samples collected from January through December 2006. The results of the distribution 

system sampling are summarized on Table 4-10. 

The most noticeable change in the distribution system samples since the system began operation was a 

decrease in arsenic concentration. Baseline arsenic concentrations ranged from 49.6 to 99.9 μg/L and 

averaged 68.7 μg/L for all three sampling locations. After the performance evaluation began, arsenic 

concentrations were reduced to ≤5.0 μg/L (or 2.4 μg/L on average), which were similar to the arsenic 

concentrations in the system effluent.

Lead concentrations ranged from 0.3 to 4.0 μg/L, with none of the samples exceeding the action level of 

15 μg/L. Copper concentrations ranged from 6.5 to 604 μg/L, with no samples exceeding the 1,300 μg/L 

action level. Measured pH values ranged from 7.4 to 8.1 and averaged 7.7, which were 0.4 units higher 

than the avearge pH value immediately after the adsorption vessels. Compared to an average value of 8.2 

before the treatment sytem became operational, the lowered pH values appeared to have some effects on 

the lead and copper concentrations in the distribution system. However, the effects did not follow a trend, 

with the lead concentrations becoming mostly lower (decreasing from 1.3 to 0.8 μg/L [on average] at the 
40

Table 4-10. Distribution System Sampling Results

Sampling Events 

Location Middle School High School Cafeteria Sampling Date Stagnation Time (hr) pHAlkalinity As Fe Mn PbCu Stagnation Time (hr) pHAlkalinity As Fe Mn PbCu Stagnation Time (hr) pHAlkalinity As Fe

MnPbCu

BL1 06/15/05 14.5 8.3 334 52.0 <25 1.9 1.9 114 14.8 8.3 330 53.0 <25 1.2 2.3 115 15.0 8.3 330 77.7 <25 5.9 11.5 381

BL2 07/21/05 15.0 8.1 330 54.4 70.9 13.5 1.2 7.3 15.3 8.2 330 79.2 32.8 6.0 2.0 44.8 15.5 8.1 330 53.3 <25 6.8 2.9 106

BL3 08/24/05 15.6 8.2 317 83.1 <25 2.2 0.3 23.9 15.7 8.2 321 85.8 <25 1.2 0.9 72.5 15.8 8.2 321 84.7 <25 2.1 0.3 23.2

BL4 09/19/05 13.0 8.1 330 49.6 <25 3.3 1.9 40.1 13.3 8.1 330 51.4 <25 1.5 1.5 77.3 13.5 8.1 326 99.9 <25 2.4 1.9 44.4

1 01/05/06 14.8 7.7 343 2.1 <25 <0.1 0.8 209 14.5 7.7 348 3.5 <25 2.4 2.3 308 15.0 7.6 334 1.4 <25 <0.1 0.5 15.4

2 02/01/06 15.0 7.9 312 3.4 <25 0.4 0.3 119 15.2 8.1 312 4.4 <25 0.2 0.8 214 15.0 8.1 312 3.8 <25 0.6 0.6 250

3 03/14/06 15.0 7.6 310 1.4 <25 0.8 0.9 278 15.2 7.8 314 2.0 <25 0.8 1.8 259 15.3 7.8 318 1.3 <25 0.9 0.9 19.7

4 04/11/06 15.3 7.9 323 3.1 <25 0.3 1.0 113 15.0 7.9 311 5.0 <25 0.6 1.6 337 15.2 7.9 315 3.6 <25 0.3 0.8 16.0

5 05/09/06 10.8 7.6 326 1.3 <25 0.3 0.4 86.3 14.8 7.7 331 2.0 <25 0.7 0.7 164 14.7 7.7 322 1.2 <25 0.1 0.4 6.5

6 06/06/06 14.7 7.8 305 1.0 <25 0.1 1.0 234 14.8 7.7 309 2.0 <25 1.9 0.7 565 14.6 8.0 322 0.7 <25 0.2 0.6 14.9

7 07/19/06 NA(a) 7.9 319 1.2 <25 2.8 1.4 237 14.3 7.9 319 1.9 <25 4.8 2.0 316 15.3 8.0 315 0.9 <25 0.5 1.8 24.1

8 08/16/06 Operator did not take sample, building is not being used. 15.0 7.7 310 1.7 <25 0.6 2.0 96.6 16.3 7.7 306 1.5 <25 <0.1 0.8 16.0

9 09/15/06 Operator did not take sample, building is not being used. 15.8 7.7 328 1.5 <25 <0.1 3.3 322 15.5 7.8 337 0.8 <25 <0.1 1.0 26.2

10 10/11/06 Operator did not take sample, building is not being used. 15.5 7.5 344 1.5 <25 0.3 4.0 538 15.7 7.5 349 1.1 26.0 0.1 1.9 74.4

11 11/08/06 Operator did not take sample, building is not being used. 15.6 7.4 353 4.3 <25 0.4 1.8 604 14.5 7.3 343 3.8 <25 0.1 2.5 116

12 12/12/06 Operator did not take sample, building is not being used. 15.0 7.4 335 1.5 <25 0.4 2.5 427 16.3 7.4 341 1.4 <25 0.6 1.7 60.8

Lead action level = 15 μg/L; copper action level = 1.3 mg/L 

μg/L as unit for all analytes except for pH (S.U.) and alkalinity (mg/L [as CaCO3]).

BL = Baseline Sampling; NA = Not Available
41

middle school and from 4.2 to 1.1 μg/L [on average] at the cafeteria) and the copper concentrations 

becoming mostly higher (increasing from 46.3 to 182.3 μg/L [on average] at the middle school and from 

77.4 to 345.9 μg/L [on average] at the high school).

Alkalinity levels ranged from 305 to 353 mg/L (as CaCO3). Iron was detected in one of the samples; 

manganese concentrations ranged from <0.1 to 4.8 μg/L. The arsenic treatment system did not seem to 

affect these water quality parameters in the distribution system. 

4.6 System Cost

System cost is evaluated based on the capital cost per gpm (or gpd) of the design capacity and the O&M 

cost per 1,000 gal of water treated. The capital cost includes the cost for equipment, site engineering, and 

installation. The O&M cost includes the cost for media replacement and disposal, electrical power use, 

and labor. 

4.6.1 Capital Cost. The capital investment for equipment, site engineering, and installation of the 

treatment system was $138,642 (see Table 4-11). The equipment cost was $94,662 (or 68% of the total 

capital investment), which included $55,566 for the skid-mounted APU-50LL-CS-S-2-AVH unit, 

$21,516 for the CO2 pH control system, $13,200 for the AD-33 media ($300/ft3 or $8.57/lb to fill two 

vessels), $2,580 for shipping, and $1,800 for labor. 

Table 4-11. Capital Investment Cost for APU-50LL-CS-S-2-AVH System

Description Quantity Cost

% of Capital 

Investment

Equipment Cost

APU Skid-Mounted System (Unit) 1 $55,566 –

CO2 pH Control System 1 $21,516 –

AD-33 Media (ft3) 44 $13,200 –

Shipping – $2,580 –

Vendor Labor – $1,800 –

Equipment Total – $94,662 68

Engineering Cost

Vendor Labor/Travel – $11,800 –

Subcontractor Labor/Travel – $12,500 –

Engineering Total – $24,300 18

Installation Cost

Subcontractor Labor – $12,574 –

Vendor Labor – $4,860 –

Vendor/ Subcontractor Travel – $2,246 –

Installation Total – $19,680 14

Total Capital Investment – $138,642 100

The engineering cost included the cost for preparing three submittal packages for the exception request, 

permit application, and supplemental information for the permit (see Section 4.3.1). The engineering cost 

was $24,300, or 18% of the total capital investment.

The installation cost included the equipment and labor to unload and install the skid-mounted unit, 

perform piping tie-ins and electrical work, load, and backwash the media, perform system shakedown and 
42

startup, and conduct operator training. The installation cost was $19,680, or 14% of the total capital 

investment.

The total capital cost of $138,642 was normalized to the system’s rated capacity of 40 gpm (57,600 gpd), 

which resulted in $3,466/gpm of design capacity ($2.41/gpd). The capital cost also was converted to an 

annualized cost of $13,086/yr using a capital recovery factor (CRF) of 0.09439 based on a 7% interest 

rate and a 20-year return period. Assuming that the system operated 24 hours a day, 7 days a week at the 

system design flowrate of 40 gpm to produce 21,024,000 gal of water per year, the unit capital cost would 

be $0.62/1,000 gal. Because the system operated an average of 4.2 hr/day at approximately 40 gpm (see 

Table 4-7), producing an estimated 8,841,100 gal of water during the performance evaluation study or 

3,679,200 gal of water annually, the unit capital cost increased to $3.56/1,000 gal at this reduced rate of 

use.

4.6.2 Operation and Maintenance Cost. The O&M cost included the cost for such items as 

media replacement and disposal, CO2 usage, electricity consumption, and labor (Table 4-12). Although 

media replacement did not occur during the system performance evaluation, the media replacement cost 

would have represented the majority of the O&M cost and was estimated to be $11,190 to change out the 

lead vessel. This media change-out cost would have included the cost for media, underbedding, freight, 

labor, travel, spent media analysis, and media disposal fee. This cost was used to estimate the media 

replacement cost per 1,000 gal of water treated as a function of the projected lead vessel media run length 

at the 10 μg/L arsenic breakthrough from the lag vessel (Figure 4-18).

The chemical cost associated with system operation included the cost for NaClO for prechlorination and 

CO2 gas for pH adjustment. NaClO had already been used at the site prior to the installation of the APU

unit for disinfection purposes prior to distribution. The presence of the APU system did not affect the use 

rate of the NaClO solution. Therefore, the incremental chemical cost for chlorine was negligible. The 

50-lb CO2 cylinder was replaced four times a month during the system performance evaluation. Each 

change-out cost $31.52, which included the replacement and delivery charges. The CO2 cost for the study 

period was $3,656 or $0.41/1,000 gal of water treated. The calculated annual CO2 cost, including 

delivery, was $1,513.

Comparison of electrical bills supplied by the utility prior to system installation and since startup did not 

indicate a noticeable increase in power consumption. Therefore, electrical cost associated with operation 

of the system was assumed to be negligible.

Under normal operating conditions, routine labor activities to operate and maintain the system consumed 

20 min per day, 5 days per week, as noted in Section 4.4.3. The labor cost for the performance evaluation 

study was $4,045 or $0.46/1,000 gal of water treated. The calculated annual labor cost was $1,690. 

Therefore, the estimated labor cost was $0.46/1,000 gal of water treated. This estimation assumed that 

maintenance and operational procedures were consistently performed through the completion of the 

system performance evaluation. 
43

Table 4-12. Operation and Maintenance Cost for APU-50LL-CS-S-2-AVH System

Cost Category Value Assumptions

Estimated Volume Processed (gal) 8,841,000 889 total operational days

Media Replacement and Disposal Cost

Media Replacement ($) $6,600 $300/ft3 for 22 ft3 (one media vessel)

Underbedding and Freight for 

Media and Gravel Shipping ($)

$330

Travel and per diem ($) $1,000

Vendor and Subcontractor Labor ($) $2,160

Media Disposal ($) $1,100 Including spent media analysis

Subtotal $11,190

Media Replacement and Disposal 

($/1,000 gal)

See Figure 

4-18 

Based upon lead vessel media run length at 10-

μg/L arsenic breakthrough from lag vessel

CO2 Usage

Annual CO2 cost ($) $1,513 Based on CO2 consumption (50-lb cylinders) 

and delivery

Unit CO2 Cost ($/1,000 gal) $0.41

Electricity Cost

Electricity ($/1,000 gal) $0.001 Electrical cost assumed negligible

Labor Cost

Average Weekly Labor (min) 100 20 min/day, 5 day/week

Annual Labor Cost ($) $1,690 Labor rate = $19.50/hr

Unit Labor Cost ($/1,000 gal) $0.46

Total O&M Cost/1,000 gal See Figure 

4-18

Media replace cost (based upon lead vessel 

media run length at 10-μg/L arsenic 

breakthrough from lag vessel) + $0.41 (CO2

cost) + $0.46 (labor cost)
44

$0.00

$0.50

$1.00

$1.50

$2.00

$2.50

$3.00

$3.50

$4.00

$4.50

$5.00

$5.50

$6.00

$6.50

$7.00

$7.50

$8.00

$8.50

0 10 20 30 40 50 60 70 80 90 100

Media Working Capacity, Bed Volumes (x1000)

Cost ($/1,000 gal)

O&M cost

Media replacement cost

Note: One bed volume equals 22 ft3 (165 gal)

Figure 4-18. Media Replacement and Other Operation and Maintenance Cost
45

5.0 REFERENCES

Battelle. 2004. Revised 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. 2005. Final System Performance Evaluation Study Plan: U.S. EPA Demonstration of Arsenic 

Removal Technology at the Webb Consolidated Independent School District in Bruni, Texas. 

Prepared under Contract No. 68-C-00-185, Task Order No. 0029 for U.S. Environmental 

Protection Agency, National Risk Management Research Laboratory, Cincinnati, OH. 

Chen, A.S.C., L. Wang, J. Oxenham, and W. Condit. 2004. Capital Costs of Arsenic Removal

Technologies: U.S. EPA Arsenic Removal Technology Demonstration Program Round 1. 

EPA/600/R-04/201. U.S. Environmental Protection Agency, National Risk Management 

Research Laboratory, Cincinnati, OH. 

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. 2001. National Primary Drinking Water Regulations: Arsenic and Clarifications to Compliance 

and New Source Contaminants Monitoring. Fed. Register, 40 CFR Parts 9, 141, and 142. 

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, DC. 

EPA. 2003. Minor Clarification of the National Primary Drinking Water Regulation for Arsenic. 

Federal Register, 40 CFR Part 141.

Wang, L., W. Condit, and A. 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. 
APPENDIX A

OPERATIONAL DATA
A-1

Table A-1. EPA Arsenic Demonstration Project at Bruni, TX — Daily System Operation Log Sheet
A-2

Table A-1. EPA Arsenic Demonstration Project at Bruni, TX — Daily System Operation Log Sheet
A-3

Table A-1. EPA Arsenic Demonstration Project at Bruni, TX — Daily System Operation Log Sheet
A-4

Table A-1. EPA Arsenic Demonstration Project at Bruni, TX — Daily System Operation Log Sheet
A-5

Table A-1. EPA Arsenic Demonstration Project at Bruni, TX — Daily System Operation Log Sheet
A-6

Table A-1. EPA Arsenic Demonstration Project at Bruni, TX — Daily System Operation Log Sheet
A-7

Table A-1. EPA Arsenic Demonstration Project at Bruni, TX — Daily System Operation Log Sheet
A-8

Table A-1. EPA Arsenic Demonstration Project at Bruni, TX — Daily System Operation Log Sheet
A-9

Table A-1. EPA Arsenic Demonstration Project at Bruni, TX — Daily System Operation Log Sheet
A-10

Table A-1. EPA Arsenic Demonstration Project at Bruni, TX — Daily System Operation Log Sheet

(a) Bed volume = 44 ft3 or 328 gal (equivalent to volume of media in two vessels). NA = not available

(b) Totalizer or Vessel A re-set on 01/12/06, 05/23/06, 06/15/06, 01/26/07, and 02/02/07. Light green highlight indicates calculated value

(c) Totalizer for Vessel B re-set on 01/12/06, 05/26/06, 06/15/06, 01/26/07, and 02/02/07. Red highlight indicates system or well pump not operating 

(d) Starting 08/10/06, totalizer readings for Vessels A and B are from gal since last backwash reading. Orange highlight indicates parameter cannot be measured

(e) Estimated master totalizer readings due to suspicious reported data. or is otherwise suspect

(f) Operational data not collected week of November 20, 2006.

(h) Operational data not collected week of December 18th and 25th 2006 due to holidays. 
APPENDIX B 

ANALYTICAL DATA
B-1

Table B-1. Analytical Results from Treatment Plant Sampling at Bruni, TX 

Sampling Date 12/08/05(a) 12/13/05(b) 01/05/06 01/17/06 02/01/06

Sampling Location IN AP TA TB IN AP TA TB IN AP TA TB IN AP TA TB IN AP TA TB

Parameter Unit

Bed Volume 10^3 - - NA NA - - 0.2 0.2 - - 0.6 0.6 - - 1.2 1.2 - - 2.0 2.0

Alkalinity (CaCO3) mg/L

317 321 330 352 326 330 330 321 334 334 312 312 334 330 321 312 320 320 342 325

- - - - - - - - - - - - - - - - - - - - 

Fluoride mg/L 0.5 0.6 0.5 0.4 - - - - 0.5 0.6 0.6 0.7 - - - - 0.5 0.6 0.5 0.6

Sulfate mg/L 104 104 103 100 - - - - 104 104 112 114 - - - - 105 104 98 103

Nitrate (as N) mg/L <0.05 <0.05 <0.05 <0.05 - - - - <0.05 <0.05 <0.05 <0.05 - - - - <0.05 <0.05 <0.05 <0.05

Total P (as PO4) mg/L

0.03 0.1 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03

- - - - - - - - - - - - - - - - - - - - 

Silica (as SiO2) mg/L

41.8 41.5 13.5 1.7 43.3 43.5 25.7 6.4 41.7 42.3 34.2 31.8 43.8 42.8 39.9 39.6 41.7 42.6 41.6 38.9

- - - - - - - - - - - - - - - - - - - - 

Turbidity NTU

0.3 <0.1 <0.1 <0.1 <0.1 0.1 0.2 0.2 0.2 0.4 0.2 0.2 1.1 0.4 0.6 0.3 0.7 0.3 0.2 0.3

- - - - - - - - - - - - - - - - - - - - 

pH S.U. 8.2 7.4 7.1 7.3 8.2 7.2 7.2 7.2 8.1 8.1 7.4 7.3 8.0 8.0 7.1 7.1 8.1 7.1 7.3 7.4

Temperature 0C 26.6 26.7 24.8 24.7 24.1 24.0 24.0 23.0 23.5 23.5 23.2 23.1 25.7 25.9 25.1 24.2 26.7 26.5 26.2 26.2

DO mg/L 1.8 2.3 0.9 1.3 1.5 1.5 1.8 2.0 2.1 2.2 2.1 2.0 2.4 1.6 1.5 1.4 1.3 1.4 1.5 1.3

ORP mV 325 679 387 371 379 592 499 425 234 533 671 686 257 538 690 700 239 465 605 680

Free Chlorine (as 

Cl2) mg/L - 1.0 0.1 - - 0.6 - - - 2.0 - 1.5 - 1.5 - 1.7 - 1.6 - 1.7

Total Chlorine (as 

Cl2) mg/L - 1.6 0.3 - - - - - - 2.1 - 2.1 - 1.8 - 1.7 - 1.5 - 1.7

Total Hardness

(as CaCO3) mg/L 17.1 19.3 27.9 47.2 - - - - 19.4 19.1 11.6 15.8 - - - - 23.7 22.2 33.0 17.1

Ca Hardness (as 

CaCO3) mg/L 11.3 13.4 17.2 29.4 - - - - 12.0 11.9 7.6 9.9 - - - - 17.0 16.9 25.1 13.8

Mg Hardness (as 

CaCO3) mg/L 5.8 5.9 10.7 17.9 - - - - 7.4 7.2 4.0 5.9 - - - - 6.7 5.3 7.9 3.3

As (total) μg/L

51.4 62.2 3.9 4.0 55.7 55.8 3.6 3.5 51.5 60.1 1.8 1.5 58.8 60.4 4.6 6.3 61.4 56.2 3.4 2.8

- - - - - - - - - - - - - - - - - - - - 

As (soluble) μg/L 53.1 61.0 3.4 2.2 - - - - 56.5 51.3 1.3 1.3 - - - - 54.3 50.8 3.0 2.9

As (particulate) μg/L <0.1 1.2 0.5 1.8 - - - - <0.1 8.7 0.4 0.2 - - - - 7.1 5.4 0.4 <0.1

As (III) μg/L 35.8 3.3 2.9 1.6 - - - - 40.4 1.5 1.2 1.2 - - - - 40.8 3.1 2.9 2.4

As (V) μg/L 17.3 57.7 0.6 0.5 - - - - 16.1 49.8 0.2 <0.1 - - - - 13.5 47.7 0.1 0.5

Fe (total) μg/L

<25 <25 <25 <25 <25 <25 <25 <25 <25 <25 <25 <25 28.8 <25 <25 <25 <25 <25 <25 <25

- - - - - - - - - - - - - - - - - - - - 

Fe (soluble) μg/L <25 <25 <25 <25 - - - - <25 <25 <25 <25 - - - - <25 <25 <25 <25

Mn (total) μg/L

4.3 4.3 1.8 5.0 3.7 3.4 1.1 1.1 3.9 3.3 <0.1 <0.1 4.5 4.4 0.5 0.2 3.2 3.4 <0.1 <0.1

- - - - - - - - - - - - - - - - - - - - 

Mn (soluble) μg/L 4.2 3.4 1.6 5.1 - - - - 3.7 3.3 <0.1 0.2 - - - - 3.6 3.5 <0.1 <0.1

(a) Chlorine measurements taken on 12/09/05. 

(b) Water quality measurements taken on 12/15/05.

IN = at wellhead; AP = after pH adjustment; TA = after Tank A; TB = after Tank B.

NA = not available.
B-2

Table B-1. Analytical Results from Treatment Plant Sampling at Bruni, TX (Continued)

Sampling Date 02/15/06 02/28/06(a) 03/14/06 03/28/06(b) 04/11/06(c)

Sampling Location IN AP TA TB IN AP TA TB IN AP TA TB IN AP TA TB IN AP TA TB

Parameter Unit

Bed Volume 10^3 - - 2.8 2.8 - - 3.3 3.3 - - 3.6 3.6 - - 4.7 4.7 - - 6.0 6.0

Alkalinity

(CaCO3) mg/L

324 324 316 328 322 314 322 335 314 310 322 327 325 321 325 325 311 307 315 315

- - - - 314 318 310 327 - - - - - - - - - - - - 

Fluoride mg/L - - - - - - - - 0.7 0.8 0.8 0.8 - - - - 0.7 0.8 0.8 0.8

Sulfate mg/L - - - - - - - - 107 107 106 106 - - - - 106 106 107 108

Nitrate (as N) mg/L - - - - - - - - <0.05 <0.05 <0.05 <0.05 - - - - <0.05 <0.05 <0.05 <0.05

Total P (as PO4) mg/L

<0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.01 <0.01 <0.01 <0.01 - - - - <0.01 <0.01 <0.01 <0.01

- - - - <0.03 <0.03 <0.03 <0.03 - - - - - - - - - - - - 

Silica (as SiO2) mg/L

41.5 42.3 43.3 40.2 40.6 41.6 41.8 41.3 41.5 40.6 41.1 38.7 41.7 42.1 42.6 42.1 40.9 40.2 40.5 42.7

- - - - 40.7 41.0 41.5 41.2 - - - - - - - - - - - - 

Turbidity NTU

1.0 1.5 1.1 2.0 0.4 0.2 0.2 0.2 0.6 0.4 0.3 0.7 0.9 0.9 0.9 0.8 0.7 0.5 0.5 0.6

- - - - 0.4 0.2 0.3 0.2 - - - - - - - - - - - - 

pH S.U. 8.1 7.2 7.3 7.2 NA NA NA NA 8.2 7.3 7.3 7.3 8.2 7.5 7.6 7.5 NA NA NA NA

Temperature 0C 26.7 26.9 27.0 27.1 NA NA NA NA 26.3 26.7 26.5 26.6 26.5 27.2 27.4 27.4 NA NA NA NA

DO mg/L 1.1 1.6 1.5 2.1 NA NA NA NA 1.6 1.7 1.3 2.3 1.5 1.8 1.8 1.9 NA NA NA NA

ORP mV 258 546 631 663 NA NA NA NA 238 569 657 662 259 309 532 587 NA NA NA NA

Free Chlorine

(as Cl2) mg/L - 0.6 - 0.9 - NA - NA - 0.8 - 1.0 - 0.5 - 0.9 - NA - NA

Total Chlorine

(as Cl2) mg/L - 0.7 - 1.0 - NA - NA - 1.1 - 1.2 - 1.2 - 1.0 - NA - NA

Total Hardness

(as CaCO3) mg/L - - - - - - - - 20.1 21.2 22.2 24.2 - - - - 30.1 30.0 27.9 29.6

Ca Hardness (as 

CaCO3) mg/L - - - - - - - - 13.3 13.9 14.3 15.6 - - - - 22.7 22.8 21.3 22.6

Mg Hardness (as 

CaCO3) mg/L - - - - - - - - 6.8 7.3 8.0 8.5 - - - - 7.4 7.2 6.6 6.9

As (total) μg/L

61.2 64.4 4.2 3.9 61.8 61.9 2.7 2.2 60.3 62.3 2.2 1.7 46.2 50.2 1.4 1.1 55.4 57.2 1.0 0.6

- - - - 57.6 57.4 2.6 2.4 - - - - - - - - - - - - 

As (soluble) μg/L - - - - - - - - 51.9 53.5 1.5 1.5 - - - - 51.5 51.6 0.8 0.6

As (particulate) μg/L - - - - - - - - 8.3 8.9 0.7 0.2 - - - - 3.8 5.6 0.2 <0.1

As (III) μg/L - - - - - - - - 38.7 1.9 1.3 1.3 - - - - 36.5 0.5 0.5 0.4

As (V) μg/L - - - - - - - - 13.2 51.6 0.2 0.2 - - - - 15.0 51.1 0.3 0.2

Fe (total) μg/L

<25 <25 <25 <25 <25 <25 <25 <25 <25 <25 <25 <25 <25 <25 <25 <25 <25 <25 <25 <25

- - - - <25 <25 <25 <25 - - - - - - - - - - - - 

Fe (soluble) μg/L - - - - - - - - <25 <25 <25 <25 - - - - <25 <25 <25 <25

Mn (total) μg/L

3.2 3.1 0.6 0.3 5.1 3.2 <0.1 <0.1 4.1 3.2 0.3 0.2 4.9 3.7 0.3 0.1 3.5 3.5 <0.1 <0.1

- - - - 5.4 4.6 <0.1 <0.1 - - - - - - - - - - - - 

Mn (soluble) μg/L - - - - - - - - 4.1 3.1 0.3 0.2 - - - - 3.6 3.4 <0.1 <0.1

(a) Water quality parameters not measured. 

(b) Water quality measurements taken on 04/05/06. 
B-3

Table B-1. Analytical Results from Treatment Plant Sampling at Bruni, TX (Continued)

(c) Water quality measurements taken on 04/20/06. 

(d) Water quality measurements taken on 05/04/06. 

(e) Water quality measurements taken on 05/12/06. 

(f) Water quality measurements taken on 06/01/06. 

(g) Water quality measurements taken on 06/19/06. 

Sampling Date 04/25/06(c) 05/09/06(d) 05/23/06(e) 06/06/06(f) 06/20/06(g)

Sampling Location IN AP TA TB IN AP TA TB IN AP TA TB IN AP TA TB IN AP TA TB

Parameter Unit

Bed Volume 10^3 - - 7.7 3.8 - - 9.4 4.7 - - 11.0 5.5 - - 12.1 6.0 - - 14.2 7.1

Alkalinity

(CaCO3) mg/L

331 344 331 344 310 306 294 314 313 326 338 318 305 318 313 318 318 318 330 330

- - - - - - - - - - - - - - - - - - - - 

Fluoride mg/L - - - - 0.9 1.2 1.5 1.0 - - - - 0.7 0.8 0.8 0.8 - - - - 

Sulfate mg/L - - - - 111 112 113 113 - - - - 107 112 114 136 - - - - 

Nitrate (as N) mg/L - - - - <0.05 <0.05 <0.05 <0.05 - - - - <0.05 <0.05 <0.05 <0.05 - - - - 

Total P (as PO4) mg/L

<10 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10

- - - - - - - - - - - - - - - - - - - - 

Silica (as SiO2) mg/L

40.8 40.8 41.3 41.2 41.8 42.3 42.7 42.1 42.8 41.6 41.7 38.1 43.9 43.2 44.4 45.3 43.9 44.9 45.6 41.0

- - - - - - - - - - - - - - - - - - - - 

Turbidity NTU

0.2 0.2 0.7 0.1 0.2 0.2 0.2 0.3 0.3 0.5 0.3 0.2 0.6 0.5 0.7 0.8 0.7 0.7 0.6 0.6

- - - - - - - - - - - - - - - - - - - - 

pH S.U. 8.2 7.4 7.3 7.4 8.1 7.2 7.3 7.3 8.3 7.6 7.5 7.5 8.2 7.3 7.2 7.3 8.2 7.6 7.6 7.5

Temperature 0C 26.5 26.3 26.7 26.6 27.1 27.2 27.5 27.3 21.3 21.2 21.4 21.4 26.4 26.6 27.1 27.1 26.7 26.6 26.9 26.7

DO mg/L 1.3 1.6 1.6 2.0 1.3 1.8 2.1 2.4 3.1 4.1 3.4 3.5 2.1 2.6 2.1 2.2 1.7 2.6 2.1 1.9

ORP mV 327 603 650 623 279 499 610 643 271 546 597 636 299 537 594 620 234 476 516 533

Free Chlorine

(as Cl2) mg/L - 0.8 - 0.7 - 1.1 - 1.5 - 0.5 - 0.6 - 0.9 - 0.7 - 0.9 - 0.6

Total Chlorine

(as Cl2) mg/L - 1.1 - 0.8 - 1.2 - 1.5 - 0.8 - 0.7 - 0.9 - 0.8 - 1.0 - 0.6

Total Hardness

(as CaCO3) mg/L - - - - 28.6 29.3 26.8 29.8 - - - - 20.2 19.8 21.0 20.5 - - - - 

Ca Hardness (as 

CaCO3) mg/L - - - - 19.7 20.2 18.3 21.1 - - - - 12.4 12.2 13.0 12.7 - - - - 

Mg Hardness (as 

CaCO3) mg/L - - - - 9.0 9.1 8.5 8.8 - - - - 7.8 7.6 8.0 7.8 - - - - 

As (total) μg/L

56.5 59.5 1.1 0.9 62.9 63.8 1.0 0.6 54.8 50.4 1.3 0.6 58.5 57.6 1.1 0.8 67.3 66.4 3.8 1.0

- - - - - - - - - - - - - - - - - - - - 

As (soluble) μg/L - - - - 54.3 55.4 0.8 0.6 - - - - 52.3 51.6 1.1 0.8 - - - - 

As (particulate) μg/L - - - - 8.6 8.4 0.2 <0.1 - - - - 6.2 6.1 <0.1 <0.1 - - - - 

As (III) μg/L - - - - 40.2 0.7 0.5 0.5 - - - - 37.0 0.8 0.7 0.6 - - - - 

As (V) μg/L - - - - 14.1 54.6 0.3 0.1 - - - - 15.3 50.8 0.5 0.2 - - - - 

Fe (total) μg/L

<25 <25 <25 <25 <25 <25 <25 <25 28 <25 <25 <25 <25 <25 <25 <25 <25 <25 <25 <25

- - - - - - - - - - - - - - - - - - - - 

Fe (soluble) μg/L - - - - <25 <25 <25 <25 - - - - <25 <25 <25 <25 - - - - 

Mn (total) μg/L

3.1 2.9 <0.1 <0.1 3.3 3.1 <0.1 <0.1 3.9 2.9 <0.1 <0.1 2.6 3.0 <0.1 0.1 4.9 3.7 0.5 0.4

- - - - - - - - - - - - - - - - - - - - 

Mn (soluble) μg/L - - - - 3.3 3.1 <0.1 <0.1 - - - - 2.6 3.0 <0.1 <0.1 - - - - 
B-4

Table B-1. Analytical Results from Treatment Plant Sampling at Bruni, TX (Continued)

(c) Water quality measurements taken on 07/24/06.

(d) Water quality measurements taken on 08/14/06.

(e) Water quality measurements taken on 08/31/06. 

Sampling Date 07/11/06 07/19/06(c) 08/02/06 08/16/06(d) 08/30/06(e)

Sampling Location IN AP TA TB IN AP TA TB IN AP TA TB IN AP TA TB IN AP TA TB

Parameter Unit

Bed Volume 10^3 - - 15.5 7.8 - - 16.4 8.2 - - 18.1 9.0 - - 20.3 10.2 - - 22.6 11.3

Alkalinity

(CaCO3) mg/L

320 324 328 NA 319 315 319 315 316 320 312 312 310 302 298 314 342 353 340 351

- - - - 315 315 319 315 - - - - - - - - - - - - 

Fluoride mg/L 0.8 1.0 1.0 1.0 - - - - 1.1 1.3 1.3 1.3 - - - - 0.2 0.9 0.9 0.9

Sulfate mg/L 137 108 106 110 - - - - 91 107 110 112 - - - - 129 131 140 132

Nitrate (as N) mg/L <0.05 <0.05 <0.05 <0.05 - - - - <0.05 <0.05 <0.05 <0.05 - - - - <0.05 <0.05 <0.05 <0.05

Total P (as PO4) mg/L

<10 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10

- - - - <10 <10 <10 <10 - - - - - - - - - - - - 

Silica (as SiO2) mg/L

42.3 42.2 42.1 42.0 41.2 41.6 39.9 40.2 40.2 40.9 38.9 37.6 42.3 42.5 41.7 43.8 39.1 39.4 39.2 39.9

- - - - 41.4 41.6 39.7 39.7 - - - - - - - - - - - - 

Turbidity NTU

1.0 0.5 0.6 NA 0.4 0.2 0.2 0.3 0.2 0.2 0.2 0.2 0.5 0.3 0.1 0.2 0.4 0.2 0.4 0.3

- - - - 0.4 0.1 0.2 0.3 - - - - - - - - - - - - 

pH S.U. NA NA NA NA 8.1 7.4 7.8 7.7 NA NA NA NA 8.2 7.3 7.3 7.5 8.1 7.3 7.3 7.3

Temperature 0C NA NA NA NA 26.3 26.8 27.0 27.0 NA NA NA NA 26.3 27.0 26.9 27.1 25.8 26.3 26.4 26.4

DO mg/L NA NA NA NA 2.3 2.5 2.2 2.4 NA NA NA NA 2.4 2.2 2.3 2.2 3.3 2.4 2.3 2.3

ORP mV NA NA NA NA 310 390 337 312 NA NA NA NA 292 478 507 493 259 603 618 621 

Free Chlorine

(as Cl2) mg/L - NA - NA - 0.6 - 0.4 - NA - NA - 0.8 - 0.4 - 0.8 - 0.6

Total Chlorine

(as Cl2) mg/L - NA - NA - 0.7 - 0.5 - NA - NA - 0.8 - 0.5 - 1.2 - 1.0

Total Hardness

(as CaCO3) mg/L 20.0 20.4 19.7 18.7 - - - - 25.3 23.9 16.9 17.9 - - - - 24.5 24.9 21.9 25.1

Ca Hardness (as 

CaCO3) mg/L 12.6 12.8 12.6 12.1 - - - - 18.1 16.4 11.9 12.2 - - - - 17.1 17.6 15.4 16.9

Mg Hardness (as 

CaCO3) mg/L 7.4 7.6 7.1 6.6 - - - - 7.2 7.5 5.0 5.8 - - - - 7.4 7.3 6.5 8.2

As (total) μg/L

54.8 56.4 2.4 0.8 60.2 61.3 2.6 0.8 63.9 64.0 8.7 0.5 50.6 51.6 3.3 1.1 68.7 69.3 6.4 1.3

- - - - 61.8 60.2 2.4 0.8 - - - - - - - - - - - - 

As (soluble) μg/L 50.4 52.0 2.0 0.7 - - - - 54.4 56.9 7.7 0.4 - - - - 56.4 56.5 5.3 1.3

As (particulate) μg/L 4.4 4.4 0.4 <0.1 - - - - 9.5 7.1 1.0 <0.1 - - - - 12.3 12.7 1.1 <0.1

As (III) μg/L 34.2 0.7 0.7 0.6 - - - - 40.7 0.5 0.4 0.4 - - - - 42.0 1.2 1.1 1.0

As (V) μg/L 16.2 51.3 1.3 0.1 - - - - 13.7 56.4 7.3 <0.1 - - - - 14.4 55.4 4.2 0.3

Fe (total) μg/L

49 <25 <25 <25 <25 <25 <25 <25 <25 <25 <25 <25 <25 <25 <25 <25 <25 <25 <25 <25

- - - - <25 <25 <25 <25 - - - - - - - - - - - - 

Fe (soluble) μg/L 38 <25 <25 <25 - - - - <25 <25 <25 <25 - - - - <25 <25 <25 <25

Mn (total) μg/L

6.0 4.0 0.7 0.6 3.7 3.2 0.2 0.1 3.5 3.4 0.1 0.1 3.4 3.1 0.2 0.1 3.4 3.4 0.2 <0.1

- - - - 3.7 3.0 0.2 0.1 - - - - - - - - - - - - 

Mn (soluble) μg/L 5.4 3.4 0.1 <0.1 - - - - 3.5 3.2 0.2 0.2 - - - - 3.5 3.4 0.2 <0.1
B-5

Table B-1. Analytical Results from Treatment Plant Sampling at Bruni, TX (Continued)

(c)Water quality measurements taken on 11/10/06.

Sampling Date 09/15/06 09/28/06 10/11/06 10/31/06 11/08/06(c)

Sampling Location IN AP TA TB IN AP TA TB IN AP TA TB IN AP TA TB IN AP TA TB

Parameter Unit

Bed Volume 10^3 - - 24.0 12.0 - - 24.4 12.2 - - 25.0 12.5 - - 25.6 12.8 - - 26.2 13.1

Alkalinity

(CaCO3) mg/L

335 337 342 342 344 347 331 349 355 353 349 349 350 352 342 361 340 345 336 349

- - - - - - - - 349 349 331 344 - - - - - - - - 

Fluoride mg/L - - - - 0.5 0.5 0.5 0.5 - - - - 0.7 0.7 0.9 0.7 - - - - 

Sulfate mg/L - - - - 105 102 104 105 - - - - 117 117 120 117 - - - - 

Nitrate (as N) mg/L - - - - <0.05 <0.05 <0.05 <0.05 - - - - <0.05 <0.05 <0.05 <0.05 - - - - 

Total P (as PO4) mg/L

<10 <10 <10 <10 <10 10.0 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10

- - - - - - - - <10 <10 <10 <10 - - - - - - - - 

Silica (as SiO2) mg/L

41.7 41.3 42.5 44.3 40.5 39.9 40.2 41.8 39.6 42.7 41.8 42.6 40.5 40.5 42.6 48.5 39.9 40.1 39.8 41.3

- - - - - - - - 42.2 42.0 41.1 41.7 - - - - - - - - 

Turbidity NTU

0.4 0.9 0.5 0.4 0.3 0.3 0.4 0.4 1.2 0.6 0.5 0.4 1.1 0.7 0.6 0.7 0.8 0.8 1.3 1.2

- - - - - - - - 1.0 0.8 0.7 0.8 - - - - - - - - 

pH S.U. NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA 8.2 7.2 7.3 7.2

Temperature 0C NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA 26.3 26.9 26.8 26.8

DO mg/L NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA 3.0 1.9 2.3 1.8

ORP mV NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA 284 507 646 646

Free Chlorine

(as Cl2) mg/L - NA - NA - NA - NA - NA - NA - NA - NA - 0.9 - 0.7

Total Chlorine

(as Cl2) mg/L - NA - NA - NA - NA - NA - NA - NA - NA - 1.8 - 1.1

Total Hardness

(as CaCO3) mg/L - - - - 25.7 26.8 26.9 30.1 - - - - 23.9 24.0 27.3 41.2 - - - - 

Ca Hardness (as 

CaCO3) mg/L - - - - 18.7 19.3 19.4 21.8 - - - - 16.7 16.7 20.6 32.5 - - - - 

Mg Hardness (as 

CaCO3) mg/L - - - - 7.0 7.5 7.6 8.3 - - - - 7.2 7.3 6.7 8.7 - - - - 

As (total) μg/L

53.1 51.6 4.8 1.0 56.4 58.1 3.2 1.1 53.9 53.0 3.5 1.1 58.7 58.6 2.8 0.6 62.0 64.0 4.4 2.1

- - - - - - - - 50.5 51.1 3.2 1.1 - - - - - - - - 

As (soluble) μg/L - - - - 52.3 53.1 3.2 1.0 - - - - 53.4 53.0 2.3 0.6 - - - - 

As (particulate) μg/L - - - - 4.1 5.0 <0.1 <0.1 - - - - 5.3 5.7 0.6 <0.1 - - - - 

As (III) μg/L - - - - 37.9 0.9 0.7 0.5 - - - - 36.9 0.7 0.4 0.3 - - - - 

As (V) μg/L - - - - 14.4 52.3 2.5 0.5 - - - - 16.5 52.3 1.9 0.2 - - - - 

Fe (total) μg/L

76 190 29 <25 163 <25 29.6 <25 79 <25 <25 <25 <25 <25 <25 <25 46 <25 <25 <25

- - - - - - - - 113 <25 <25 <25 - - - - - - - - 

Fe (soluble) μg/L - - - - 134 <25 <25 <25 - - - - <25 <25 <25 <25 - - - - 

Mn (total) μg/L

2.9 13.6 <0.1 <0.1 14.7 3.5 0.6 0.3 10.1 4.0 0.9 <0.1 6.3 3.3 0.8 0.3 8.6 4.7 0.5 0.2

- - - - - - - - 12.3 3.6 0.9 <0.1 - - - - - - - - 

Mn (soluble) μg/L - - - - 14.5 3.5 0.5 0.2 - - - - 6.1 3.1 0.5 0.2 - - - - 
B-6

Table B-1. Analytical Results from Treatment Plant Sampling at Bruni, TX (Continued)

(c) Water quality measurements taken on 12/04/06.

(d) Water quality measurements taken on 01/17/07.

(e) Only As speciation samples collected starting 02/13/07. 

(f) Water quality measurements taken on 02/09/07. 

 

Sampling Date 11/28/06(c) 12/12/06 01/22/07(d) 02/13/07(e,f) 03/13/07

Sampling Location IN AP TA TB IN AP TA TB IN AP TA TB IN AP TA TB IN AP TA TB

Parameter Unit

Bed Volume 10^3 - - 26.8 13.4 - - 27.1 13.6 - - 28.0 14.0 - - 28.7 14.4 - - 30.0 15.0

Alkalinity

(CaCO3) mg/L

357 357 368 402 325 339 337 331 335 339 339 328 - - - - - - - - 

- - - - - - - - - - - - - - - - - - - - 

Fluoride mg/L 0.8 0.8 0.8 0.7 0.6 0.8 0.8 0.8 0.8 1.0 0.9 0.9 - - - - - - - - 

Sulfate mg/L 122 125 129 124 110 111 109 108 96 104 121 127 - - - - - - - - 

Nitrate (as N) mg/L <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 - - - - - - - - 

Total P (as PO4) mg/L

<10 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10 190 214 203 167 13.7 12.5 5 10.8

- - - - - - - - - - - - - - - - - - - - 

Silica (as SiO2) mg/L

41.9 41.2 47.0 25.0 41.6 41.8 40.9 40.7 40.6 40.8 38.6 37.8 41.8 42.8 40.7 42.4 41.0 41.4 50.6 95.8

- - - - - - - - - - - - - - - - - - - - 

Turbidity NTU

0.8 0.8 0.7 0.6 0.2 0.1 0.2 0.2 0.5 0.6 0.5 0.4 - - - - - - - - 

- - - - - - - - - - - - - - - - - - - - 

pH S.U. 8.2 7.4 7.0 7.0 NA NA NA NA 8.3 7.6 7.1 7.2 8.3 7.4 7.0 7.1 NA NA NA NA

Temperature 0C 24.5 25.3 22.4 21.2 NA NA NA NA 25.0 25.0 25.0 25.0 25.0 NM NM NM NA NA NA NA

DO mg/L 2.2 1.7 2.1 2.0 NA NA NA NA NM NM NM NM NM NM NM NM NA NA NA NA

ORP mV 264 563 666 678 NA NA NA NA NM NM NM NM NM NM NM NM NA NA NA NA

Free Chlorine

(as Cl2) mg/L - 0.4 - 0.5 - NA - NA - NM - NM - 0.8 - 1.0 - NA - NA

Total Chlorine

(as Cl2) mg/L - 0.6 - 1.8 - NA - NA - NM - NM - 1.0 - 1.1 - NA - NA

Total Hardness

(as CaCO3) mg/L 24.8 21.9 31.1 49.9 23.7 23.0 25.1 22.3 21.9 22.0 17.0 14.3 - - - - - - - - 

Ca Hardness (as 

CaCO3) mg/L 15.8 13.8 17.7 26.6 16.0 15.7 17.2 15.3 14.6 14.7 11.7 10.0 - - - - - - - - 

Mg Hardness (as 

CaCO3) mg/L 9.0 8.1 13.4 23.3 7.7 7.2 8.0 7.0 7.4 7.3 5.2 4.3 - - - - - - - - 

As (total) μg/L

46.0 47.4 4.0 1.5 59.0 58.8 3.4 1.3 58.4 63.6 5.2 1.7 55.7 53.7 1.1 2.3 60.2 61.0 3.2 1.1

- - - - - - - - - - - - - - - - - - - - 

As (soluble) μg/L 44.6 44.5 3.8 0.7 55.2 56.3 3.1 1.3 55.1 56.3 4.7 1.8 51.6 51.2 0.8 2.0 53.7 52.2 1.9 1.0

As (particulate) μg/L 1.4 2.9 0.2 0.8 3.8 2.5 0.3 <0.1 3.3 7.3 0.4 <0.1 4.1 2.5 0.3 0.2 6.5 8.7 1.3 <0.1

As (III) μg/L 32.5 1.1 1.0 0.6 37.8 1.4 1.1 0.9 31.3 1.7 1.6 1.5 41.6 0.9 0.6 0.5 34.1 0.9 0.6 0.9

As (V) μg/L 12.1 43.3 2.7 0.2 17.5 54.9 2.1 0.4 23.8 54.6 3.1 0.4 10.0 50.3 0.2 1.6 19.7 51.4 1.3 0.1

Fe (total) μg/L

<25 67 40 <25 53 43 <25 <25 <25 <25 <25 <25 - - - - - - - - 

- - - - - - - - - - - - - - - - - - - - 

Fe (soluble) μg/L <25 62 31 <25 <25 33 <25 <25 <25 <25 <25 <25 - - - - - - - - 

Mn (total) μg/L

3.8 5.2 1.3 0.3 4.9 4.7 0.8 0.3 4.4 3.0 0.2 <0.1 - - - - - - - - 

- - - - - - - - - - - - - - - - - - - - 

Mn (soluble) μg/L 3.8 5.2 1.2 0.2 4.6 4.6 0.6 0.2 4.5 2.9 0.4 0.3 - - - - - - - - 
B-7

Table B-1. Analytical Results from Treatment Plant Sampling at Bruni, TX (Continued)

(c) Operational data no longer available from operator. Bed volumes estimated based on historical measurements.

(d) IN sample taken on 02/24/08. 

Sampling Date 04/17/07 05/09/07 06/05/07 09/20/07 02/21/08(d)

Sampling Location IN AP TA TB IN AP TA TB IN AP TA TB IN AP TA TB IN AP TA TB

Parameter Unit

Bed Volume 10^3 - - 30.8 15.4 - - 32.2 16.1 - - 33.1 16.6 - - 41.0(c) 20.5(c) - - 50.4(c) 25.2(c)

Alkalinity

(CaCO3) mg/L - - - - - - - - - - - - - - - - - - - - 

- - - - - - - - - - - - - - - - - - - - 

Fluoride mg/L - - - - - - - - - - - - - - - - - - - - 

Sulfate mg/L - - - - - - - - - - - - - - - - - - - - 

Nitrate (as N) mg/L - - - - - - - - - - - - - - - - - - - - 

Total P (as PO4) mg/L - - - - - - - - - - - - - - - - - - - - 

- - - - - - - - - - - - - - - - - - - - 

Silica (as SiO2) mg/L - - - - - - - - - - - - - - - - - - - - 

- - - - - - - - - - - - - - - - - - - - 

Turbidity NTU - - - - - - - - - - - - - - - - - - - - 

- - - - - - - - - - - - - - - - - - - - 

pH S.U. NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA

Temperature 0C NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA

DO mg/L NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA

ORP mV NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA

Free Chlorine

(as Cl2) mg/L - NA - NA - NA - NA - NA - NA - NA - NA - NA - NA

Total Chlorine

(as Cl2) mg/L - NA - NA - NA - NA - NA - NA - NA - NA - NA - NA

Total Hardness

(as CaCO3) mg/L - - - - - - - - - - - - - - - - - - - - 

Ca Hardness (as 

CaCO3) mg/L - - - - - - - - - - - - - - - - - - - - 

Mg Hardness (as 

CaCO3) mg/L - - - - - - - - - - - - - - - - - - - - 

As (total) μg/L

67.5 69.1 4.7 1.5 54.2 59.4 5.7 2.0 51.3 49.8 3.5 0.2 NA 56.1 9.6 1.2 60.4 88.4 17.5 16.9

- - - - - - - - - - - - - - - - - - - - 

As (soluble) μg/L 55.8 54.4 3.8 1.3 46.4 49.7 5.2 2.4 46.4 46.7 3.2 0.1 - - - - - - - - 

As (particulate) μg/L 11.8 14.6 0.9 0.2 7.8 9.7 0.5 <0.1 4.9 3.0 0.3 <0.1 - - - - - - - - 

As (III) μg/L 35.3 1.2 0.9 0.9 35.4 1.2 1.3 1.8 40.4 0.4 0.2 <0.1 - - - - - - - - 

As (V) μg/L 20.5 53.2 2.8 0.4 11.0 48.5 3.9 0.6 6.1 46.4 3.0 <0.1 - - - - - - - - 

Fe (total) μg/L - - - - - - - - - - - - - - - - - - - - 

- - - - - - - - - - - - - - - - - - - - 

Fe (soluble) μg/L - - - - - - - - - - - - - - - - - - - - 

Mn (total) μg/L - - - - - - - - - - - - - - - - - - - - 

- - - - - - - - - - - - - - - - - - - - 

Mn (soluble) μg/L - - - - - - - - - - - - - - - - - - - - 
B-8

Table B-1. Analytical Results from Treatment Plant Sampling at Bruni, TX (Continued)

(c) Operational data no longer available from operator. Bed volumes estimated based on historical measurements. 

Sampling Date 04/16/08 05/15/08

Sampling Location IN AP TA TB IN AP TA TB

Parameter Unit

Bed Volume 10^3 - - 53.7(c) 26.7(c) - - 54.7(c) 27.4(c)

Alkalinity

(CaCO3) mg/L - - - - - - - - 

- - - - - - - - 

Fluoride mg/L - - - - - - - - 

Sulfate mg/L - - - - - - - - 

Nitrate (as N) mg/L - - - - - - - - 

Total P (as PO4) mg/L - - - - - 

- 

- - - 

- - - - - - - 

Silica (as SiO2) mg/L - - - - - - - - 

- - - - - - - - 

Turbidity NTU - - - - - - - - 

- - - - - - - - 

pH S.U. NA NA NA NA NA NA NA NA

Temperature 0C NA NA NA NA NA NA NA NA

DO mg/L NA NA NA NA NA NA NA NA

ORP mV NA NA NA NA NA NA NA NA

Free Chlorine

(as Cl2) mg/L - NA - NA - NA - NA

Total Chlorine

(as Cl2) mg/L - NA - NA - NA - NA

Total Hardness

(as CaCO3) mg/L - - - - - - - - 

Ca Hardness (as 

CaCO3) mg/L - - - - - - - - 

Mg Hardness (as 

CaCO3) mg/L - - - - - - - - 

As (total) μg/L 59.2 57.2 27.6 0.8 59.9 57.7 45.4 5.2

- - - - - - - - 

As (soluble) μg/L - - - - - - - - 

As (particulate) μg/L - - - - - - - - 

As (III) μg/L - - - - - - - - 

As (V) μg/L - - - - - - - - 

Fe (total) μg/L - - - - - - - - 

- - - - - - - - 

Fe (soluble) μg/L - - - - - - - - 

Mn (total) μg/L - - - - - - - - 

- - - - - - - - 

Mn (soluble) μg/L - - - - - - - -