EPA/600/R-05/159 

December 2005 

Arsenic Removal from Drinking Water by 

Adsorptive Media 

EPA Demonstration Project at Rimrock, AZ 

Six-Month Evaluation Report 

by 

Lili Wang 

Julia Valigore 

Abraham S.C. Chen 

Battelle 

Columbus, OH 43201-2693 

Contract No. 68-C-00-185 

Task Order No. 0019 

 

for 

Thomas J. Sorg 

Task Order Manager 

Water Supply and Water Resources Division 

National Risk Management Research Laboratory 

Cincinnati, Ohio 45268 

National Risk Management Research Laboratory 

Office of Research and Development 

U.S. Environmental Protection Agency 

Cincinnati, Ohio 45268 
ii
DISCLAIMER 

The work reported in this document was funded by the United States Environmental Protection Agency 

(EPA) under Task Order (TO) 0019 of Contract No. 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.
FOREWORD 

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

community and to link researchers with their clients. 

Sally Gutierrez, Director 

National Risk Management Research Laboratory

iv
ABSTRACT 

This report documents the activities performed and the results obtained from the first six months of the 

arsenic removal treatment technology demonstration project in Rimrock, AZ. The objectives of the 

project are to evaluate: (1) the effectiveness of the AdEdge Arsenic Package Unit-100 (APU-100) AD33TM media system in removing arsenic to meet the new arsenic maximum contaminant level (MCL) of 

10 μg/L, (2) the reliability of the treatment system, (3) the simplicity of required system operation, (4) the 

maintenance (O&M) and operator’s skill levels, and (5) the cost-effectiveness of the technology. The 

project also is characterizing water in the distribution system and process residuals produced by the 

treatment process. The types of data collected included system operation, water quality (both across the 

treatment train and in the distribution system), process residuals, and capital and O&M costs. 

The APU-100 treatment system consisted of two 36-inch-diameter, 72-inch-tall fiberglass-reinforcedplastic (FRP) vessels, each containing 22 ft3

 of AD-33TM media. The media is Bayoxide E33 iron-based 

adsorption media developed by Bayer AG and branded under the name of AD-33TM by AdEdge. The 

system was originally designed to treat 90 gpm of water supplied by two production wells. Due to the 

loss of one well, the treatment flowrate was reduced by more than half, which prompted a change in 

system configuration from parallel to series (lead/lag). Following the conversion to series configuration 

in the field, the APU-100 system with a design capacity of 45 gpm began regular operation on June 24, 

2004. The average flowrate through each vessel was 31.5 gpm, corresponding to an average empty bed 

contact time (EBCT) of 5.2 minutes per vessel and 10.4 minutes for both vessels. 

 

Through the period June 24, 2004 through December 22, 2004, the APU-100 system operated for 12 

hours a day on a timer for a total of 2,172 hours. The system treated approximately 4,109,000 gallons of 

water, or 25,000 bed volumes (BV), which was approximately 38% of the vendor-estimated working 

capacity for adsorptive media. Arsenic breakthrough from the lead and lag vessels was 3 μg/L and 1.3 

μg/L, respectively. Total arsenic concentration in raw water ranged from 48.3 to 81.4 μg/L with As(V) 

being the predominating species, averaging 57.3 μg/L. Prechlorination, although not required for 

oxidation, was performed for disinfection. The residual chlorine measured before and after the treatment 

vessels was comparable, indicating little or no chlorine consumption by the AD-33TM media. 

Concentrations of iron, manganese, silica, orthophosphate, and other ions in raw water were not high 

enough to impact arsenic removal by the media. 

Backwash was performed monthly since August 2004 with raw water at approximately 50 gpm, or 7 

gpm/ft2

. Each vessel was backwashed for 15 minutes, producing between 631 to 910 gallons of water. 

Two sets of backwash water samples were collected during the first six months of system operation. 

Arsenic concentrations in the backwash water from the lead and lag vessels were approximately 48.0 

μg/L and <3.0 μg/L, respectively, indicating that the lead vessel had less capacity to remove arsenic, and 

that the lag vessel was still very effective at removing arsenic during backwash. A backwash recycle loop 

enabled the system to reclaim nearly 100% of the wastewater produced by blending it with the chlorinated 

water at a rate of 0.5 gpm. 

Comparison of the distribution system sampling results before and after operation of the APU-100 system 

began showed a decrease in the average arsenic concentration (from 44.6-55.2 μg/L to 18.8-21.8 μg/L) at 

each of the three sampling locations. However, the concentrations measured after system operation began 

were higher than those at the plant effluent. This was probably caused by the blending of treated water by 

the APU-100 system with untreated water from other wells in the distribution system. Neither lead nor 

copper concentrations appeared to have been affected by the operation of the system. 

v
The capital investment cost of $90,757 includes $66,235 for equipment, $11,372 for site engineering, and 

$13,150 for installation. Using the system’s rated capacity of 45 gpm (or 64,800 gpd), the capital cost 

was $2,017/gpm (or $1.40/gpd) and the equipment-only cost was $1,472/gpm (or $1.02/gpd). These 

calculations did not include the cost of the building construction. 

O&M costs included only incremental costs associated with the APU-100 system, such as media 

replacement and disposal, chemical supply, electricity, and labor. Although not incurred during the first 

six months of operation, the media replacement cost would represent the majority of the O&M cost, and 

was estimated to be $9,940 per vessel. This cost was used to estimate the media replacement cost per 

1,000 gallons of water treated as a function of the projected media run length to the 10-μg/L arsenic 

breakthrough. O&M costs will be refined once the actual throughput and cost at the time of the media 

replacement become available. 

vi
CONTENTS 

FOREWORD ...............................................................................................................................................iv 

ABSTRACT..................................................................................................................................................v 

FIGURES...................................................................................................................................................viii 

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

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

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

1.0 INTRODUCTION .................................................................................................................................1 

1.1 Background...................................................................................................................................1 

1.2 Treatment Technologies for Arsenic Removal.............................................................................1 

1.3 Project Objectives.........................................................................................................................2 

2.0 CONCLUSIONS....................................................................................................................................3 

3.0 MATERIALS AND METHODS...........................................................................................................4 

3.1 General Project Approach.............................................................................................................4 

3.2 System O&M and Cost Data Collection.......................................................................................5

3.3 Sample Collection Procedures and Schedules..............................................................................6 

3.3.1 Source Water Sample Collection.....................................................................................6 

3.3.2 Treatment Plant Water Sample Collection ......................................................................6 

3.3.3 Backwash Water Sample Collection ...............................................................................6 

3.3.4 Residual Solid Sample Collection ...................................................................................6 

3.3.5 Distribution System Water Sample Collection................................................................6 

3.4 Sampling Logistics .......................................................................................................................8 

3.4.1 Preparation of Arsenic Speciation Kits............................................................................8 

3.4.2 Preparation of Sampling Coolers.....................................................................................8 

3.4.3 Sample Shipping and Handling .......................................................................................8 

3.5 Analytical Procedures...................................................................................................................9 

4.0 RESULTS AND DISCUSSION ..........................................................................................................10 

4.1 Facility Description ....................................................................................................................10 

4.1.1 Source Water Quality ....................................................................................................10 

4.1.2 Distribution System .......................................................................................................11 

4.2 Treatment Process Description...................................................................................................12 

4.3 System Installation .....................................................................................................................15 

4.3.1 Permitting ......................................................................................................................15 

4.3.2 System Installation, Shakedown, and Startup................................................................15 

4.3.3 Shed Construction..........................................................................................................18 

4.4 System Operation .......................................................................................................................18 

4.4.1 Operational Parameters..................................................................................................18 

4.4.2 Backwash.......................................................................................................................19 

4.4.3 Residual Management ...................................................................................................19 

4.4.4 System/Operation Reliability and Simplicity ................................................................20 

4.5 System Performance ...................................................................................................................21 

4.5.1 Treatment Plant Sampling .............................................................................................21 

4.5.2 Backwash Water Sampling............................................................................................22 

4.5.3 Distribution System Water Sampling ............................................................................26 

4.6 System Costs...............................................................................................................................28 

vii
4.6.1 Capital Costs..................................................................................................................28 

4.6.2 Operation and Maintenance Costs.................................................................................29 

5.0 REFERENCES ....................................................................................................................................32 

APPENDIX A: OPERATIONAL DATA 

APPENDIX B: ANALYTICAL DATA TABLES 

FIGURES 

Figure 4-1. Pre-Demonstration Site Conditions.........................................................................................10 

Figure 4-2. Schematic of AdEdge APU-100 System with Series Operation.............................................14 

Figure 4-3. Process Flow Diagram and Sampling Locations.....................................................................16

Figure 4-4. Photograph of the APU-100 System .......................................................................................17 

Figure 4-5. Photograph of the Backwash Recycle System ........................................................................17 

Figure 4-6. Sun Shed Structure over the Treatment System......................................................................18 

Figure 4-7. Concentration of Arsenic Species at the Inlet, after Vessel A, and after Vessel B .................25 

Figure 4-8. Total Arsenic Breakthrough Curve .........................................................................................26 

Figure 4-9. Media Replacement and O&M Costs for the Rimrock Treatment System .............................31 

TABLES 

Table 1-1. Summary of Arsenic Removal Demonstration Technologies and Source Water Quality 

Parameters .............................................................................................................................................2 

Table 3-1. Pre-Demonstration Study Activities and Completion Dates ......................................................4 

Table 3-2. Evaluation Objectives and Supporting Data Collection Activities.............................................5 

Table 3-3. Sample Collection Schedule and Analyses.................................................................................7 

Table 4-1. Rimrock, AZ Source Water Quality Data.................................................................................11 

Table 4-2. Rimrock, AZ Distribution System Water Quality Data............................................................12 

Table 4-3. Physical and Chemical Properties of AD-33TM Media.............................................................13 

Table 4-4. Design Features of the APU-100 System .................................................................................15 

Table 4-5. Summary of APU-100 System Operations...............................................................................19 

Table 4-6. Backwash Event Summary.......................................................................................................20 

Table 4-7. Summary of Arsenic, Iron, and Manganese Analytical Results...............................................23 

Table 4-8. Summary of Water Quality Parameter Measurements .............................................................23 

Table 4-9. Backwash Water Sampling Results..........................................................................................26 

Table 4-10. Distribution System Sampling Results ...................................................................................27 

Table 4-11. Summary of Capital Investment Costs ...................................................................................29 

Table 4-12. Summary of O&M Costs........................................................................................................30 

viii
ABBREVIATIONS AND ACRONYMS 

∆p differential pressure 

AA activated alumina 

AAL American Analytical Laboratories 

ADEQ Arizona Department of Environmental Quality 

Al aluminum 

APU arsenic package unit 

As arsenic 

AWC Arizona Water Company 

bgs below ground surface 

BV bed volume(s) 

Ca calcium 

CCR Consumer Confidence Report 

Cl chlorine 

Cu copper 

DO dissolved oxygen 

EBCT empty bed contact time 

EPA U.S. Environmental Protection Agency 

F fluoride 

Fe iron 

FRP fiberglass-reinforced-plastic 

GFH granular ferric hydroxide 

GFO granular ferric oxide 

gpd gallons per day 

gpm gallons per minute 

HDPE high-density polyethylene 

ICP-MS inductively coupled plasma-mass spectrometry 

ID identification 

IX ion exchange 

kwh kilowatt-hour(s) 

LCR (EPA) Lead and Copper Rule 

MCL maximum contaminant level 

MDL method detection limit 

MDWCA Mutual Domestic Water Consumers Association 

Mg magnesium 

mg/L milligrams per liter 

ix
μg/L micrograms per liter 

μm micrometer 

Mn manganese 

mph miles per hour 

mV millivolts 

Na sodium 

NA not applicable 

NaOCl sodium hypochlorite 

ND not detected 

NS not sampled 

NSF NSF International 

NTU nephlemetric turbidity units 

O&M operation and maintenance 

ORD Office of Research and Development 

ORP oxidation-reduction potential 

P&IDs piping and instrumentation diagrams 

Pb lead 

PO4 orthophosphate 

psi pounds per square inch 

PVC polyvinyl chloride 

QA quality assurance 

QA/QC quality assurance/quality control 

QAPP Quality Assurance Project Plan 

RPD relative percent difference 

SDWA Safe Drinking Water Act 

SiO2 silica 

SO4 sulfate 

STMGID South Truckee Meadows General Improvement District 

STS Severn Trent Services 

TCLP Toxicity Characteristic Leaching Procedure 

TDS total dissolved solids 

TO Task Order 

TOC total organic carbon 

x
ACKNOWLEDGMENTS 

The authors wish to extend their sincere appreciation to the staff of the Arizona Water Company (AWC) 

in Phoenix and Sedona, Arizona. The AWC staff monitored the treatment system and collected samples 

from the treatment system and distribution system on a regular schedule throughout this reporting period. 

This performance evaluation would not have been possible without their support and dedication. 

xi
1.0 INTRODUCTION 

1.1 Background 

The Safe Drinking Water Act (SDWA) mandates that U.S. Environmental Protection Agency (EPA) 

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

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

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

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

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

2001). 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 in order to reduce compliance costs. As 

part of this Arsenic Rule Implementation Research Program, EPA’s Office of Research and Development 

(ORD) proposed a project to conduct a series of full-scale, on-site demonstrations of arsenic removal 

technologies, process modifications, and engineering approaches applicable to small systems. Shortly 

thereafter, an announcement was published in the Federal Register requesting water utilities interested in 

participating in the first round of this EPA-sponsored demonstration program to provide information on 

their water systems. In June 2002, EPA selected 17 sites from a list of 115 sites to be the host sites for the 

demonstration studies. The Arizona Water Company (AWC) water system in Rimrock, AZ was selected 

as one of the 17 Round 1 host sites for the demonstration program. 

In September 2002, EPA solicited proposals from engineering firms and vendors for cost-effective arsenic 

removal treatment technologies for the 17 host sites. EPA received 70 technical proposals for the 17 host 

sites, with each site receiving from one to six proposals. In April 2003, an independent technical panel 

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

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

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

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

the respective states, selected one technical proposal for each site. AdEdge, using the Bayoxide E33 

media developed by Bayer AG, was selected for Rimrock. AdEdge has given the E33 media the 

designation “AD-33TM.” 

1.2 Treatment Technologies for Arsenic Removal

The technologies selected for the 12 Round 1 EPA arsenic removal demonstration host sites include nine 

adsorptive media systems, one anion exchange system, one coagulation/filtration system, and one process 

modification with iron addition. Table 1-1 summarizes the locations, technologies, vendors, and key 

source water quality parameters (including arsenic, iron, and pH) of the 12 demonstration sites. The 

technology selection and system design for the 12 demonstration sites have been summarized in an EPA 

report (Wang et al., 2004) posted at the following EPA Web site: http://www.epa.gov/ORD/NRMRL/ 

arsenic/resource.htm. 

1
Table 1-1. Summary of Arsenic Removal Demonstration Technologies and Source 

Water Quality Parameters 

Source Water Quality

Demonstration Site

Technology 

(Media) Vendor

Design 

Flowrate 

(gpm)

As 

(μg/L)

Fe 

(μg/L) pH

Bow, NH AM (G2) ADI 70(a) 39 <25 7.7 

Rollinsford, NH AM (E33) AdEdge 100 36(b) 46 8.2

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

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

Climax, MN C/F Kinetico 140 39(b) 546(c) 7.4 

Lidgerwood, ND SM Kinetico 250 146(b) 1,325(c) 7.2 

Desert Sands MDWCA, NM AM (E33) STS 320 23(b) 39 7.7 

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

Rimrock, AZ AM (E33) AdEdge 90(a) 50 170 7.2 

Valley Vista, AZ AM (AAFS50) Kinetico 37 41 <25 7.8 

Fruitland, ID IX Kinetico 250 44 <25 7.4 

STMGID, NV AM (GFH) USFilter 350 39 <25 7.4 

AM = adsorptive media process; C/F = coagulation/filtration process; IX = ion exchange process; 

SM = system modification; MDWCA = Mutual Domestic Water Consumers Association; 

STMGID = South Truckee Meadows General Improvement District; STS = Severn Trent Services. 

(a) Due to system reconfiguration from parallel to series operation, the design flowrate is reduced by 50%. 

(b) Arsenic exists mostly as As(III). 

(c) Iron exists mostly as soluble Fe(II). 

1.3 Project Objectives 

The objective of the Round 1 arsenic demonstration program is to conduct 12 full-scale arsenic treatment 

technology demonstration studies on the removal of arsenic from drinking water supplies. The specific 

objectives were to: 

• Evaluate the performance of the arsenic removal technologies for use on small 

systems. 

• Determine the simplicity of required system operation and maintenance (O&M) 

and operator’s skill levels. 

• Determine the cost-effectiveness of the technologies. 

• Characterize process residuals produced by the technologies. 

This report summarizes the results gathered during the first six months of the AdEdge system operation 

from June 24 through December 24, 2004. The types of data collected included system operational data, 

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

characterization data, and capital and preliminary O&M cost data. 

2
2.0 CONCLUSIONS 

The AdEdge arsenic package unit (APU)-100 was installed and operated at Rimrock, AZ since June 24, 

2004. Based on the information collected during the first six months of operation, the following 

preliminary conclusions were made relating to the overall project objectives. 

Performance of the arsenic removal technology for use on small systems 

• The APU-100 was effective at reducing As(V) in the raw water from 48.3-81.4 μg/L to less than 

10 μg/L. After treating approximately 4.1 million gallons or 25,000 bed volumes of water, total 

arsenic concentrations in the effluent from the lead and lag vessels were measured at 3 μg/L and 

1.3 μg/L, respectively. 

• The presence of low concentrations of iron, manganese, silica, orthophosphate, and other ions in 

the water did not appear to impact arsenic removal by the AD-33TM media. 

• Little or no chlorine was consumed by the AD-33TM media. 

Simplicity of required system operation and maintenance and operator’s skill levels 

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

record operational parameters. The APU-100 was equipped with automated controls to initiate 

backwash by timer and/or differential pressure. 

• Operation of the APU-100 did not require additional skills beyond those necessary to operate the 

existing water supply equipment. 

Cost-effectiveness of the technology 

• The capital investment for the APU-100 was $90,757, including $66,235 for equipment, $11,372 

for site engineering, and $13,150 for installation. 

• Based on a design capacity of 45 gpm, the capital cost was $2,017/gpm (or $1.40/gpd) and the 

equipment-only cost was $1,472/gpm (or $1.02/gpd), not including the cost for building 

construction. 

• Media replacement cost, although not incurred during the first six months, represents the majority 

of the O&M cost. The media replacement for one vessel was estimated to be $9,940. 

Characteristics of process residuals produced by the technology 

• The APU-100 was backwashed monthly, generating between 1,500 and 1,700 gallons of water. 

Nearly 100% of the wastewater was reclaimed via a backwash recycle system.

• Backwash effluent contained less arsenic than the backwash influent, indicating some arsenic 

removal by the media during backwashing. 

3
3.0 MATERIALS AND METHODS 

3.1 General Project Approach 

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

the AdEdge treatment system began on June 24, 2004. Table 3-2 summarizes the types of data collected 

and/or considered as part of the technology evaluation process. The overall system performance was 

evaluated based on its ability to consistently remove arsenic to below the target MCL of 10 μg/L through 

the collection of weekly/biweekly water samples across the treatment train. The reliability of the system 

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

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

Repair and Maintenance Log Sheet. 

Simplicity of the system operation and the level of operator skill required were evaluated based on a 

combination of quantitative data and qualitative considerations, including any pre-treatment and/or posttreatment requirements, level of system automation, operator skill requirements, task analysis of the 

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

requirements, and general knowledge needed for safety requirements and chemical processes. The 

staffing requirements to maintain the system operation were recorded on an Operator Labor Hour Log 

Sheet. 

The cost-effectiveness of the system was evaluated based on the cost per 1,000 gallons ($/1,000 gallons) 

of water treated. This task required the tracking of capital costs such as equipment, engineering, and 

installation costs, as well as O&M costs for media replacement and disposal, chemical supply, electrical

power use, and labor hours. The capital costs have been detailed in an EPA report (Chen et al., 2004)

Table 3-1. Pre-Demonstration Study Activities and Completion Dates 

Activity Date 

Introductory Meeting Held July 31, 2003 

Request for Quotation Issued to Vendor August 4, 2003 

Draft Letter of Understanding Issued August 13, 2003 

Final Letter of Understanding Issued September 9, 2003 

Vendor Quotation Submitted to Battelle September 9, 2003 

Purchase Order Completed and Signed October 6, 2003 

Letter Report Issued October 17, 2003 

Draft Study Plan Issued November 26, 2003 

Engineering Package Submitted to ADEQ December 11, 2003 

Final Study Plan Issued December 19, 2003 

Approval to Construct Granted by ADEQ February 18, 2004 

Construction Permit Issued by County March 15, 2004 

APU-100 Unit Shipped March 30, 2004 

Initial System Installation and Shakedown Completed April 22, 2004 

Initial Approval of Construction Granted by ADEQ April 29, 2004 

Shed Construction Completed May 21, 2004 

System Re-Configuration Completed May 27, 2004 

Revised Engineering Package Submitted to ADEQ June 1, 2004 

Final Approval of Construction Granted by ADEQ June 15, 2004 

Performance Evaluation Begun June 24, 2004 

4
Table 3-2. Evaluation Objectives and Supporting Data Collection Activities 

Evaluation Objectives Data Collection 

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

Reliability -Unscheduled downtime for system 

-Frequency and extent of repairs to include labor hours, problem description, 

description of materials, and cost of materials 

Simplicity of Operation 

and Operator Skill 

-Pre- and post-treatment requirements 

-Level of system automation for data collection and system operation 

-Staffing requirements including number of operators and labor hours 

-Task analysis of preventative maintenance to include labor hours per month and 

number and complexity of tasks 

-Chemical handling and inventory requirements 

-General knowledge needed of safety requirements and chemical processes 

Cost-Effectiveness -Capital costs including equipment, engineering, and installation 

-O&M costs including chemical and/or media usage, electricity, and labor 

Residual Management -Quantity of the residuals generated by the process 

-Characteristics of the aqueous and solid residuals 

that is posted at the following EPA Web site: http://www.epa.gov/ORD/NRMRL/arsenic/resource.htm. 

Data on O&M costs were limited to chemicals, electricity, and labor hours because media replacement 

did not take place during the six months of operation. 

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

water produced during each backwash event and the need to replace the media upon arsenic breakthrough. 

Backwash water was sampled and analyzed for chemical constituents. 

3.2 System O&M and Cost Data Collection 

The plant operator performed daily, weekly (changed to biweekly since November 3, 2004), and monthly 

system O&M and data collection following the instructions provided by Battelle. The plant operator 

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

System Operation Log Sheet; checked the sodium hypochlorite drum level; and conducted visual 

inspections to ensure normal system operations on a regular basis. If any problems occurred, the plant 

operator would contact the Battelle Study Lead, who then would determine if AdEdge should be 

contacted for troubleshooting. The plant operator recorded all relevant information on the Repair and 

Maintenance Log Sheet. Weekly or biweekly, the plant operator measured water quality parameters, 

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

chlorine and recorded the data on a Weekly On-Site Water Quality Parameters Log Sheet. Monthly 

backwash data also were recorded on a Backwash Log Sheet. 

Capital costs for the APU-100 consisted of costs for equipment, site engineering, and system installation. 

The O&M costs consisted of costs for the media replacement and spent media disposal, chemical and 

electricity consumption, and labor. The sodium hypochlorite consumption was tracked on the Daily 

System Operation Log Sheet. Electrical consumption was estimated from an electric meter. Labor hours 

for various activities, such as the 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 filling field logs, replenishing the sodium hypochlorite solution, ordering 

supplies, performing system inspection, and others as recommended by AdEdge. The demonstrationrelated work included activities such as performing field measurements, collecting and shipping samples, 

5
and communicating with the Battelle Study Lead and AdEdge. The demonstration-related activities were 

recorded but not used for the cost analysis. 

3.3 Sample Collection Procedures and Schedules 

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

distribution system, and adsorptive vessel backwash. Table 3-3 provides the sampling schedule and 

analytes measured during each sampling event. Specific sampling requirements for arsenic speciation, 

analytical methods, sample volumes, containers, preservation, and holding times are presented in Table 4-

1 of the EPA-endorsed Quality Assurance Project Plan (QAPP) (Battelle, 2003). 

3.3.1 Source Water Sample Collection. The plant operator collected one set of source water 

samples from Montezuma Haven Well No. 2 for detailed water quality analyses (see Table 3-3) on 

October 22, 2003. The sample tap was flushed for several minutes before sampling; special care was 

taken to avoid agitation, which might cause unwanted oxidation. An arsenic speciation kit and sample 

bottles with appropriate preservatives were used for sample collection. 

3.3.2 Treatment Plant Water Sample Collection. During the system performance study, the 

plant operator collected water samples across the treatment train in 250-mL plastic bottles containing 

nitric acid preservative for metal analyses and in additional plastic bottles containing appropriate 

preservatives for other water quality analyses. The plant operator also performed on-site arsenic 

speciation using arsenic speciation kits (see Section 3.4.1). For the first four months of the 

demonstration, samples were collected weekly on a four-week cycle at three locations (i.e. the wellhead 

[IN], after the lead vessel [TA], and after the lag vessel [TB]) for on- and off-site analyses. For the first 

week of each four-week cycle, samples were collected, speciated, and analyzed for the analytes listed 

under the monthly treatment plant analyte list (see Table 3-3). For the next three weeks, samples were 

collected and analyzed for the analytes listed under the weekly treatment plant analyte list. Since 

November 3, 2004, the weekly sampling frequency was reduced to biweekly and speciation sampling was 

reduced to bimonthly due to slow arsenic breakthrough in the treated water. Thus, the four-week 

sampling cycle became an eight-week cycle. On-site measurements also were taken after prechlorination 

(AC), in addition to IN, TA, and TB. 

3.3.3 Backwash Water Sample Collection. Backwash water samples were collected on October 

20, 2004 and December 15, 2004 from the sample taps located at the backwash water effluent line from 

each vessel. For each backwash sampling, an unfiltered sample from each vessel was collected in an 

unpreserved 1-gallon wide-mouth high-density polyethylene (HDPE) bottle for water quality analyses, 

and a 60-mL sample filtered on-site with 0.45-μm filters was collected in a 125-mL HDPE bottle 

preserved with nitric acid for metal analyses. Analytes for the backwash samples are listed in Table 3-3. 

3.3.4 Residual Solid Sample Collection. Residual solids including backwash sludge and spent 

media samples were not collected during the initial six months of this demonstration. 

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

distribution system 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 December 2003 to February 

2004, prior to the startup of the treatment system, four sets of baseline distribution water samples were 

collected from three locations within the distribution system. Following the startup of the arsenic 

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

Ideally, the sampling locations selected would have been the historical Lead and Copper Rule (LCR) 

locations served primarily by Well No. 2. However, because the distribution system of Rimrock is 

supplied by Well No. 2 and five other wells, such LCR locations do not exist (see Section 4.1.2). 

6
Table 3-3. Sample Collection Schedule and Analyses 

Sample Type 

Sample 

Locations(a)

No. of 

Samples Frequency Analytes 

Date(s) Samples 

Collected 

Source Water Wellhead (IN) 1 Once As (total, soluble, and 

particulate), As(III), 

As(V), Fe (total and 

soluble), Mn (total and 

soluble), Al (total and 

soluble), Na, Ca, Mg, Cl, 

F, SO4, SiO2, PO4, TOC, 

turbidity, pH, and 

alkalinity. 

10/22/03 

Weekly (b) On-site(c): pH, 

temperature, DO, ORP, 

Cl2 (free and total). 

Off-site: As (total), Fe 

(total), Mn (total), SiO2, 

PO4, turbidity, and 

alkalinity. 

07/07/04, 07/14/04, 

07/21/04, 08/04/04, 

08/11/04, 08/18/04, 

09/01/04, 09/08/04, 

09/15/04, 09/29/04, 

10/06/04, 10/13/04, 

10/27/04, 11/03/04, 

11/17/04, 12/01/04 

Treatment 

Plant Water

Wellhead (IN), 

after the lead 

vessel (TA), 

and after the 

lag vessel (TB) 

3 

Monthly Same as weekly sampling 

(above) plus the following 

off-site: As (soluble and 

particulate), As(III), 

As(V), Fe (soluble), Mn 

(soluble), Ca, Mg, F, 

NO3, and SO4,. 

06/30/04, 07/28/04, 

08/25/04, 09/22/04, 

10/20/04, 12/15/04 

Backwash 

Water 

Backwash 

discharge line 

from each 

vessel 

2 Monthly pH, TDS, turbidity, As 

(soluble), Fe (soluble), 

and Mn (soluble). 

10/20/04, 12/15/04 

Residual 

Solid 

Spent media 

from lead and 

lag vessels and 

backwash 

sludge from 

bag filter 

2-3 Once TCLP metals To be determined 

Distribution 

Water 

Non-LCR 

residences 

served by Well 

No. 2 and 

other wells 

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

Cu, and Pb. 

Baseline sampling: 

12/17/03, 01/06/04, 

01/21/04, 02/05/04, 

Monthly sampling: 

07/28/04, 08/26/04, 

09/22/04, 10/20/04, 

11/17/04, 12/15/04 

(a) The abbreviations in parentheses correspond to the sample locations shown in Figure 4-3. 

(b) Began biweekly sampling on November 3, 2004. 

(c) On-site measurements were performed on samples taken after prechlorination (AC), in addition to IN, TA, 

and TB. Chlorine measurements were not performed at IN. 

(d) Four baseline sampling events were performed from December 2003 to Feburary 2004 before the system 

became operational. 

7
As such, three non-LCR residences that are served by Well No. 2 and other wells were used for the 

distribution system sampling. 

 

For each location, samples were collected in one unpreserved 1-L HDPE wide-mouth bottle for metal 

analyses (preserved with nitric acid in the lab), and one unpreserved 250-mL plastic bottle for water 

quality analyses (see Table 3-3). The samples were collected following an instruction sheet developed 

according to the Lead and Copper Rule Monitoring and Reporting Guidance for Public Water Systems

(EPA, 2002). The homeowners recorded the date and time of last water use before sampling and the date 

and time of sample collection to calculate the stagnation time. All samples were collected from a coldwater faucet that had not been used for at least six hours to ensure that stagnant water was sampled. 

3.4 Sampling Logistics 

All sampling logistics including arsenic speciation kits preparation, sample cooler preparation, and 

sample shipping and handling is discussed as follows. 

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

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

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

Appendix A of the EPA-endorsed QAPP (Battelle, 2003). 

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

appropriate number and type of sample bottles, filters, and/or speciation kits needed. All sample bottles 

were new and contained appropriate preservatives. Each sample bottle was affixed with a pre-printed, 

colored-coded label consisting of the sample identification (ID), date and time of sample collection, 

collector’s name, site location, where to send the sample, analysis required, and preservative. The sample 

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

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

The sampling locations at the treatment plant were color-coded for easy identification. For example, red, 

orange, and yellow were used to designate sampling locations for IN, TA, and TB, respectively. The 

labeled bottles were then separated into ziplock bags by sampling locations and placed in the cooler. 

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

chain-of-custody forms, prepaid and addressed Federal Express air bills, and bubble wrap, were packed 

into the coolers. Except for the operator’s signature and the sample date and time, the chain-of-custody 

forms and prepaid Federal Express air bills were completed with the required information. After preparation, sample coolers were sent to the site via Federal Express for the following week’s sampling event. 

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

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

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

Sample label identifications were checked against the chain-of-custody forms and the samples were 

logged into the laboratory sample receipt log. Discrepancies noted by the sample custodians were 

addressed with the plant operator by the Battelle Study Lead. 

Samples for metal analyses were stored at Battelle’s ICP-MS Laboratory. Samples for other water quality 

analyses were packed in coolers at Battelle and picked up by a courier from Battelle’s subcontract 

laboratories, including AAL in Columbus, OH and TCCI Laboratories in New Lexington, OH. The 

chain-of-custody forms remained with the samples from the time of preparation through analysis and final 

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

required hold time, and disposed of properly thereafter. 

8
3.5 Analytical Procedures 

The analytical procedures described in Section 4.0 of the EPA-endorsed QAPP (Battelle, 2003) were 

followed by the Battelle ICP-MS Laboratory, AAL, and TCCI Laboratories. Field measurements of pH, 

temperature, DO, and ORP were conducted by the plant operator using a WTW Multi 340i handheld 

meter, which was calibrated for pH and DO prior to use following the procedures provided in the user’s 

manual. The ORP probe also was checked by measuring the ORP of the standard solution and comparing 

it to the expected value. The plant operator collected a water sample in a clean plastic beaker and placed 

the WTW probe in the beaker until a stable value was reached. The plant operator also performed free 

and total chlorine measurements using Hach chlorine test kits following the user’s manual. 

Laboratory quality assurance/quality control (QA/QC) of all methods followed the guidelines provided in 

the QAPP (Battelle, 2003). Data quality in terms of precision, accuracy, method detection limit (MDL), and 

completeness met the criteria established in the QAPP (i.e., relative percent difference [RPD] of 20%, 

percent recovery of 80-120%, and completeness of 80%). The quality assurance (QA) data associated with 

each analyte will be presented and evaluated in a QA/QC Summary Report to be prepared under separate 

cover and to be shared with the other 11 demonstration sites included in this project. 

9
4.0 RESULTS AND DISCUSSION 

4.1 Facility Description 

The Montezuma Haven Wells No. 1 and No. 2 in Rimrock, AZ with a combined capacity of 90 gpm were 

selected for this demonstration study. These and five other wells serve a population of 2,556. From the 

summer of 2003 to October 2003, Wells No. 1 and No. 2 were taken off-line for repairs and 

redevelopment. Figure 4-1 shows the site condition in late July 2003. It was later discovered that Well 

No. 1 had become dry and that Well No. 2 produced no more than 35 gpm of water. This reduced 

flowrate prompted a change to the configuration of the adsorption vessels from parallel to series. 

Well No. 2 is 6 inches in diameter and 165 ft deep with an open borehole extending from 80 to 165 ft 

below ground surface (bgs). During the first six months of the study, Well No. 2 operated 12 hours per 

day on a timer, i.e., from 8:00 am to 8:00 pm before November 22, 2004, and from 11:00 pm to 11:00 am 

afterwards (the operating time was adjusted to prevent the system components from being damaged under 

freezing conditions). The actual flowrate from Well No. 2 to the treatment system was approximately 31 

gpm. 

Well No. 3, a 1,000-ft-deep well located at the same site, was drilled in December 2002 and produced a 

flow of 315 gpm. This well became a main supply well and was controlled by level sensors in storage 

tanks. Before entering the distribution system, a 12% sodium hypochlorite solution was used to maintain 

a chlorine residual of about 0.3 mg/L (as Cl2) in the distribution system. 

4.1.1 Source Water Quality. Source water samples were collected for analysis from Well No. 2 

on October 22, 2003. The results of the source water analyses, along with those provided by the facility 

to EPA for the demonstration site selection and those independently collected and analyzed by EPA, are 

presented in Table 4-1. 

Figure 4-1. Pre-Demonstration Site Conditions 

10
Table 4-1. Rimrock, AZ Source Water Quality Data 

Parameter Units 

Facility 

Data(a)

Facility 

Data 

EPA 

Data 

Battelle 

Data 

Sampling Date Not specified 12/30/2002 10/03/2002 10/22/2003 

Well ID Wells No. 1&2 Well No. 3 Wells No. 1&2 Well No. 2 

pH – 7.2 7.6 NS 7.1 

Total Alkalinity mg/L(b) 334 444 374 378 

Total Hardness mg/L(b) 300 NS 330 335 

Chloride mg/L 25.0 NS 30.8 32.0 

Fluoride mg/L NS 0.2 NS 0.5 

Nitrate (as N) mg/L NS 0.1 NS NS 

Sulfate mg/L 13.0 12.2 11.6 9.5 

Silica (as SiO2) mg/L 27.8 NS 26.3 24.8 

Orthophosphate mg/L <0.065(c) NS <0.065 <0.10 

TOC mg/L NS NS NS 3.4(d)

As (total) μg/L 50.0 15.0 52.0 63.6 

As (total soluble) μg/L NS NS NS 64.8 

As (particulate) μg/L NS NS NS <0.10 

As(III) μg/L NS NS NS <0.10 

As(V) μg/L NS NS NS 64.8 

Total Fe μg/L 170(c) NS 170 36 

Soluble Fe μg/L NS NS NS <25 

Total Al μg/L NS NS <25 13 

Soluble Al μg/L NS NS NS <10 

Total Mn μg/L NS NS <0.4 7.5 

Soluble Mn μg/L NS NS NS 8.1 

Total Na mg/L 35.0 93 41.6 40.3 

Total Ca mg/L 69.0 NS 80.2 82.8 

Total Mg mg/L 31.0 NS 31.6 31.0 

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

(b) As CaCO3. 

(c) Provided by EPA. 

(d) Datum is questionable. 

TOC = total organic carbon; NS = not sampled. 

 

Based on the October 22, 2003 sampling results, the total arsenic concentration in Well No. 2 was 63.6 

μg/L, with arsenic existing solely as As(V). Because the arsenic is As(V) and highly adsorbed with AD33TM media, prechlorination upstream of the treatment process was not required. The AD-33TM media 

adsorbs arsenic more effectively at pH values ranging from 6.9 to 9.0, but less effectively at the upper end 

of the range. The source water pH value was 7.1; therefore, pH adjustment was not recommended. 

The adsorption capacity of AD-33TM media can be impacted by high levels of competing ions such as 

silica, phosphate, and fluoride. Concentrations of these ions in the source water appeared to be low 

enough not to affect the media’s adsorption of arsenic. The iron concentration (36 μg/L) in Well No. 2 

water was sufficiently low that pretreatment for iron removal prior to adsorption was not required. 

4.1.2 Distribution System. The distribution system is currently supplied by Montezuma Haven 

Wells No. 2, No. 3, and four other production wells. Well No. 1 is no longer in service. Water from Well 

No. 2 enters the distribution system via a 6-inch-diameter underground main. Chlorinated water from 

11
Well No. 3 enters the distribution system at the fence line of the treatment plant. Well water blends 

within the distribution system and is stored in a 200,000-gallon tank. The distribution transmission main 

is constructed of 6-inch-diameter asbestos cement pipes. 

Water from the distribution system is sampled periodically for state and federal compliance with safe 

drinking water standards. Every month, three samples are collected from the distribution system for 

bacteria analysis. Under the LCR, samples have been collected from customer taps at 14 locations every 

three years. The monitoring results for 2003 are summarized in Table 4-2. 

 

Table 4-2. Rimrock, AZ Distribution System Water Quality Data(a) 

Parameter Units Detected Range 

Alpha emitters pCi/L ND to 3.5 

Arsenic (total) μg/L 20 to 54 

Barium mg/L 0.3 to 0.4 

Chromium μg/L 11 to 15 

Fluoride mg/L 0.2 to 0.4 

Nitrate (as N) mg/L ND to 0.9 

Selenium μg/L 3.2 to 4.2 

Radium-226 pCi/L ND to 0.2 

Sodium mg/L 38 to 45 

Uranium μg/L 1.3 to 4.5 

Copper(b) mg/L 0.43 

Radon(c) pCi/L 60 

(a) All other constituents analyzed for AWC’s Consumer Confidence Report 

(CCR) were under the respective detection limits (AWC, 2004). 

(b) Parameter was sampled in 2002. 

(c) Parameter was sampled in 1999. 

ND = not detected. 

4.2 Treatment Process Description 

The APU-100 system is a fixed-bed, down-flow adsorption system used for small water systems with 

flows typically under 100 gpm. The treatment system uses Bayoxide® E33 granular ferric oxide (GFO) 

adsorptive media developed by Bayer AG for the removal of arsenic from drinking water supplies. This 

media is branded and referred to as AD-33TM by AdEdge. Table 4-3 presents physical and chemical 

properties of the media. AD-33TM is delivered in a dry crystalline form and has received NSF 

International (NSF) approval for use in drinking water under NSF Standard 61. 

The original design of the APU-100 system consisted of two pressure vessels operating in parallel to treat 

an anticipated flowrate of 90 gpm. However, because Well No. 1 was no longer in service, the vessels 

were reconfigured to operate in series to treat half of that flow (i.e., 45 gpm). 

For series operation, when the media in the lead vessel completely exhausts its capacity and/or 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 non-hazardous waste after passing the EPA’s Toxicity Characteristic Leaching Procedure 

(TCLP) test. After new media is loaded into the “lead” vessel, it is switched to the lag position and the 

“lag” vessel is switched to the lead position. The series operation can better utilize the media capacity 

when compared to parallel operation. 

12
Table 4-3. Physical and Chemical Properties of AD-33TM Media 

Physical Properties 

Parameter Value 

Matrix Iron oxide composite 

Physical form Dry granular media 

Color Amber 

Bulk Density (g/cm3) 0.45 

Bulk Density (lb/ft3) 28.1 

BET Area (m2/g) 142 

Attrition (%) 0.3 

Moisture Content (%) <15% by weight 

Particle size distribution 10 x 35 mesh 

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 

 Source: Bayer AG. 

The APU-100 system consists of a bag filter assembly, two pressure vessels arranged in series with hub 

and lateral underdrains, a backwash recycle system, piping with an automated valve assembly, and 

instrumentation and controls such as a flow meters and totalizers, pressure and differential pressure 

gauges, and ball valve sample ports. Figure 4-2 is a simplified instrumentation diagram of the APU-100 

system with series configuration. The design features of the APU-100 system are summarized in Table 4-

4, and a flow diagram along with the sampling/analysis schedule are presented in Figure 4-3. The major 

components of the treatment process are discussed as follows. 

• Intake. Raw water is pumped from Montezuma Haven Well No. 2 at a flowrate of 

approximately 31 gpm. 

• Prechlorination. Although prechlorination was not needed to oxidize the water, a sodium 

hypochlorite feed port was installed on the inlet piping to the treatment system for disinfection. 

A 12% sodium hypochlorite (NaOCl) solution is fed with a metering pump via polyvinyl chloride 

(PVC) tubing. The target residual chlorine in the treated water is 0.3 mg/L (as Cl2). The metering pump is interlocked with the well pump so that both pumps can be on or off at the same time. 

• Bag Filter Filtration. After prechlorination, a 25-μm bag filter with replaceable polypropylene 

felt bags is used to remove any sediment from the intake to protect the treatment equipment.

• Adsorption. The APU-100 system consists of two 36-inch-diameter, 72-inch-tall pressure 

vessels in series configuration, each containing 22 ft3

 of AD-33TM media supported by a gravel 

13
underbed. Although originally proposed to contain 27 ft3

 of media in each vessel, less media was 

loaded to provide additional freeboard for backwash. The vessels are of fiberglass-reinforcedplastic (FRP) construction, rated for 150 psi working pressure, skid mounted, and piped to a valve 

rack mounted on a polyurethane coated, welded steel frame. Based on the actual flowrate of 31 

gpm, the empty bed contact time (EBCT) and hydraulic loading for each vessel are approximately 

5.3 minutes and 4.4 gpm/ft2

, respectively. Figure 4-4 is a photograph of the APU-100 system. 

• Backwash. Based upon a set time or a set pressure differential (Δp), the adsorption vessels are 

taken off line for backwash one at a time using raw water from the well. The purpose of the 

backwash is to remove particulates and/or media fines accumulating in the beds. Backwash may 

be initiated either manually or automatically. Each backwash event produces 8 to 10 BV of 

wastewater. 

• Backwash Water Recycling. Due to the lack of sewer or other wastewater discharge facilities 

on site, a backwash recycle loop was added to the system to reclaim the wastewater. The recycle 

system consists of a 25-μm bag filter, a 3,000-gallon polyethylene tank, and a reclaim pump. 

Wastewater from the storage tank is metered into the system intake between the NaOCl injection 

point and the bag filter at a rate of 0.5 gpm. Figure 4-5 is a photograph of the recycle system. 

Figure 4-2. Schematic of AdEdge APU-100 System with Series Operation 

14
Table 4-4. Design Features of the APU-100 System 

Parameter Parallel Operation(a) Series Operation(b) 

Pretreatement NaOCl NaOCl 

No. of adsorbers 2 2 

Vessel size (inch) 36 D × 72 H 36 D × 72 H 

Type of media AD-33TM AD-33TM

Quantity of media (ft3/vessel) 27 22 

Backwash flowrate (gpm) 56 50 

Backwashing hydraulic loading (gpm/ft2) 8 7 

Backwash frequency, per month 1 1 

Total backwash duration (min) 50-75 30 

Design flowrate (gpm) 90 45 

Actual flowrate (gpm) - 31 

EBCT (min/vessel) 4.5 5.3 

Average use rate (gpd) 50,000 22,320 

Hydraulic utilization (%) 38.6 50.0 

Estimated working capacity (BV) 66,000(c) 66,000(d)

Bed volumes/day (BV/day) 124 (per vessel) 136 (per vessel) 

Estimated gallons to breakthrough (gal) 26,700,000(c) 10,900,000(d)

Estimated media life (months) 17.8 16.2 

Estimated media life (yrs) 1.5 1.3 

(a) Proposed by AdEdge. 

(b) Values were modified due to the system reconfiguration. 

(c) Based on 10-μg/L arsenic breakthrough from both vessels. 

(d) Based on 10-μg/L arsenic breakthrough from lead vessel. 

4.3 System Installation 

Installation of the AdEdge APU-100 system was completed in mid-April 2004. The system was 

reconfigured from parallel to series operation in mid-May. The system installation activities were carried 

out by Fann Environmental (Prescott, AZ) as a subcontractor to AdEdge. 

4.3.1 Permitting. Engineering plans for the system permit application were prepared by AdEdge and 

its subcontractor and submitted to Arizona Department of Environmental Quality (ADEQ) for approval 

on December 11, 2003. The plans included piping and instrumentation diagrams (P&IDs) and 

specifications of the APU-100 system, control panel schematics, equipment cut sheets, and drawings of a 

site plan, treatment plan, and piping plan. After the Approval to Construct was granted on February 18, 

2004, a construction permit was applied for and approved by Yavapai County in mid-March 2004. Upon 

completion of system installation, as-built drawings were submitted to ADEQ and Approval of 

Construction was granted on April 29, 2004. Following the system reconfiguration, updated information 

was submitted to ADEQ and a second approval was granted on June 15, 2004. 

4.3.2 System Installation, Shakedown, and Startup. The APU-100 system was delivered to the 

site on March 30, 2004. AdEdge’s subcontractor performed the off-loading and installation of the system, 

including piping connections to the existing intake and distribution system. The mechanical installation, 

hydraulic testing of the unit (with no media), and media loading were completed on April 20, 2004. Due 

to the loss of Well No. 1, a water line from Well No. 3 was installed to allow additional flow for media 

backwash. During startup, however, some lubricating oil (used to lubricate the pump shaft of Well No. 3) 

15
pH, TDS, turbidity,

As (soluble), Fe (soluble),

Mn (soluble)

MEDIA 

TANK

B

MEDIA 

TANK

A

INFLUENT

(MONTEZUMA HAVEN WELL #2)

BAG FILTER

Monthly

DISTRIBUTION 

SYSTEM

BACKWASH 

RECYCLE TANK

(3,000 gal)

STORAGE TANK

(200,000 gal)

DA: Cl2

Rimrock, AZ

AD-33® Technology

Design Flow: 45 gpm

Weekly

TCLP

BW

SS

Footnote

(a) On-site analyses

TA

TB

IN

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

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

As (V), Fe (total and soluble), pH(a), temperature(a), DO/ORP(a), Mn (total and soluble), As, Fe, Mn, SiO2, PO Ca, Mg, F, NO3, SO4, SiO2, PO 4, 4, turbidity, alkalinity turbidity, alkalinity

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

chlorine(a), As (total and soluble),

As (III), As (V), pH(a), temperature(a), DO/ORP(a),

Fe (total and soluble), chlorine(a), As, Fe, Mn, SiO2, PO4,

Mn (total and soluble), turbidity, alkalinity

Ca, Mg, F, NO3, SO4, SiO2, PO4,

turbidity, alkalinity

RECYCLE PUMP

AC

LEGEND

LEGEND

Influent

After Pre-Chlorination

Tank A Effluent

DA: Cl2 Chlorine Disinfection

BAG FILTER Unit Process

Process Flow

Backwash Flow

AC

SS

nsocatioLng ilpmar SteaW

BW

IN

TB

TA

Tank B Effluent

Backwash Sampling Location

Sludge Sampling Location

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

chlorine(a)

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

chlorine(a)

BAG FILTER

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

chlorine(a), As, Fe, Mn, SiO2, PO4,

turbidity, alkalinity

pH, TDS, turbidity,

As (soluble), Fe (soluble),

Mn (soluble)

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

chlorine(a), As (total and soluble),

As (III), As (V), 

Fe (total and soluble),

Mn (total and soluble),

Ca, Mg, F, NO3, SO4, SiO2, PO4,

turbidity, alkalinity

MEDIA 

TANK

B

MEDIA 

TANK

A

INFLUENT

(MONTEZUMA HAVEN WELL #2)

BAG FILTER

Monthly

DISTRIBUTION 

SYSTEM

BACKWASH 

RECYCLE TANK

(3,000 gal)

STORAGE TANK

(200,000 gal)

DA: Cl2

Rimrock, AZ

AD-33® Technology

Design Flow: 45 gpm

Weekly

TCLP

BW

SS

Footnote

(a) On-site analyses

TA

TB

IN

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

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

As (V), Fe (total and soluble), pH(a), temperature(a), DO/ORP(a), Mn (total and soluble), As, Fe, Mn, SiO2, PO Ca, Mg, F, NO3, SO4, SiO2, PO 4, 4, turbidity, alkalinity turbidity, alkalinity

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

chlorine(a), As (total and soluble),

As (III), As (V), pH(a), temperature(a), DO/ORP(a),

Fe (total and soluble), chlorine(a), As, Fe, Mn, SiO2, PO4,

Mn (total and soluble), turbidity, alkalinity

Ca, Mg, F, NO3, SO4, SiO2, PO4,

turbidity, alkalinity

RECYCLE PUMP

AC

LEGEND

LEGEND

Influent

After Pre-Chlorination

Tank A Effluent

DA: Cl2 Chlorine Disinfection

BAG FILTER Unit Process

Process Flow

Backwash Flow

AC

SS

nsocatioLng ilpmar SteaW

BW

IN

TB

TALEGEND

Tank B Effluent

Backwash Sampling Location

Sludge Sampling Location

LEGEND

Influent

After Pre-Chlorination

Tank A Effluent

DA: Cl2 Chlorine Disinfection

BAG FILTER Unit Process

Process Flow

Backwash Flow

AC

SS

nsocatioLng ilpmar SteaW

BW

IN

TB

TA

Tank B Effluent

Backwash Sampling Location

Sludge Sampling Location

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

chlorine(a)

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

chlorine(a)

BAG FILTER

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

chlorine(a), As, Fe, Mn, SiO2, PO4,

turbidity, alkalinity

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

chlorine(a), As (total and soluble),

As (III), As (V), 

Fe (total and soluble),

Mn (total and soluble),

Ca, Mg, F, NO3, SO4, SiO2, PO4,

turbidity, alkalinity

Figure 4-3. Process Flow Diagram and Sampling Locations

16
Figure 4-4. Photograph of the APU-100 System 

Figure 4-5. Photograph of the Backwash Recycle System 

17
was found in Well No. 3 water, and a decision was made not to use Well No. 3 water for media 

backwash. 

Because of the reduced flowrate (from 90 to 31 gpm), the corresponding EBCT across each vessel would 

have been more than doubled (from 4.5 minutes to 10.6 minutes) if the system configuration remained in 

parallel. To evaluate the system performance close to the originally designed EBCT and to fully utilize 

the media capacity, the vessel configuration was changed to series. The required modifications were 

made in mid-May 2004, and shakedown and startup completed in early June 2004. After the system was 

sanitized and passed bacteria tests, the performance evaluation of the APU-100 system began on June 24, 

2004. 

4.3.3 Shed Construction. After the APU-100 system was installed, a sun shed structure was built 

by AWC over the treatment system in mid-May (Figure 4-6). The dimensions of the shed structure, 

manufactured by Versa-Tube, were 12 ft × 15 ft with a height of 9.5 ft. The shed was constructed with a 

galvanized steel frame anchored to the concrete pad and sheeted with 29-gauge steel that had a specially 

coated surface. The shed was pre-engineered with a 90-mph wind load and a 30-lb/ft2

 snow loading 

capacity. From late-November to mid-December 2004, the sides and ends of the shed structure were 

enclosed with metal covering for the winter. 

Figure 4-6. Sun Shed Structure over the Treatment System 

4.4 System Operation 

4.4.1 Operational Parameters. The operational parameters for the first six months of the system 

operation are tabulated and attached as Appendix A. Key parameters are summarized in Table 4-5. From 

June 24 through December 22, 2004, the APU-100 system operated for 2,172 hours based on 12-hour 

daily operation of Well No. 2. This value represents a utilization rate of 50% over the 27-week period. 

An hour meter was installed on November 4, 2004 to accurately monitor any system downtime due to 

repairs and maintenance. 

18
Table 4-5. Summary of APU-100 System Operations 

Operational Parameter Value 

Period 06/24/04-12/22/04 

Daily Operating Time (hr) 12 

Total Operating Time (hr) 2,172 

Throughput (kgal) 4,109 

Bed Volumes (BV)(a) 25,000 

Average Flowrate (gpm) 31.5 

Range of Flowrate (gpm) 26-34 

Average EBCT (min)(b) 10.4 (5.2 per vessel) 

Range of EBCT (min)(b) 9.8-12.6 (4.9-6.3 per vessel) 

Range of Δp (psi/vessel) 3.5-6.5 

(a) 1 BV = 22 ft3 = 165 gallons. 

(b) Calculated based on 22 ft3 of media per vessel. 

The average system throughput during this 27-week period was approximately 4,109,000 gallons (or 

25,000 BV), which was 3.2% higher than that measured from the wellhead master totalizer (i.e., 

3,982,000 gallons). The flowrate readings ranged from 26 to 34 gpm and averaged 31.5 gpm. The 

average EBCT was 5.2 minutes per vessel and 10.4 minutes for both vessels. 

The Δp across each vessel ranged from 3.5 to 6.5 psi. During the startup, the hydraulic testing performed 

with no media in the vessels measured a pressure loss of 4.3 psi across each vessel at a flowrate of 33 

gpm. Therefore, the media did not cause significant pressure losses. Results of hydraulic testing 

performed for another APU-100 system with similar design for the Rollinsford, NH host site indicated 

that the controller valves were the source of elevated pressure losses (Oxenham et al., 2005). Further, the 

pressure loss across each vessel between two consecutive backwash events did not increase significantly, 

indicating that no or little particulates or media fines were accumulating in the media bed. 

4.4.2 Backwash. The APU-100 system experienced unscheduled backwashes during the first 

several months of operation when the system was set for automatic backwash at 15 psi of Δp or 27 or 28 

days of system operation (Table 4-6). It was suspected that the operation of the nearby well, Well No. 3, 

might have caused the system pressure to spike thereby initiating unscheduled backwashes. Because the 

backwashes occurred when the operator was absent, relevant operational parameters were not recorded. 

In order to monitor the backwash process and facilitate backwash water sampling, the Δp relays were 

disengaged on August 12, 2004 so that the backwash would be controlled solely by a timer. The first set 

of backwash samples was collected on October 20, 2004 when the vessels were manually backwashed. 

After another backwash was missed on November 15, 2004, the timer setting was changed from 27 or 28 

days to 30 days. The second set of backwash samples was collected on December 15, 2004. Backwash 

was performed with raw water at 48-52 gpm, or approximately 7 gpm/ft2

. Each vessel was backwashed 

for 15 minutes, generating between 631 and 910 gallons of water per vessel. 

4.4.3 Residual Management. The backwash recycle loop enabled the system to reclaim nearly 

100% of the wastewater produced by blending it with the chlorinated water at a rate of 0.5 gpm before the 

bag filter assembly. Thus, no liquid residual was generated by the APU-100. The solid residuals 

produced included backwash solids and spent media. The backwash solids were filtered by bag filters, 

which have been replaced and disposed of after each backwash event. The media was not exhausted 

during the first six months of system operation. 

19
Table 4-6. Backwash Event Summary 

Vessel 

Backwash 

Flowrate 

Backwash 

Duration 

Wastewater 

Generated(a)

Recycle 

Volume(a)

Estimated 

Time between 

Backwashes 

Date A/B gpm min gal gal days 

06/26/04 NA 511 NA 

07/15/04 800 779 NA 

07/26/04 869 770 NA 

08/10/04 631 780 NA 

08/23/04 700 530 NA 

09/26/04 

Data not available due to 

unscheduled backwashes. 

800 NA 

09/27/04(b) B 48 15 709 1,479 NA 

10/20/04(b) A 49 15 700 24 

10/20/04(b) B 49 15 800 1,481 23 

11/15/04 764 26 

11/16/04 

Data not available due to 

unscheduled backwashes. 786 1,578 27 

12/15/04(b) A 52 15 800 30 

12/15/04(b) B 52 15 910 1,610 29 

Total 9,269 9,518 

(a) Based on respective flow meter/totalizer readings. 

(b) Manual backwash. 

 NA = not available. 

4.4.4 System/Operation Reliability and Simplicity. The operational issues related to backwash 

were the primary source of concerns during system operations in this six-month reporting period. 

Because the bag filter was installed upstream of the backwash recycle tank (see Figure 4-3), the filter had 

to be replaced after each backwash event. Operations could be simplified if the bag filter was installed 

downstream of the recycle tank, allowing solids to settle prior to the bag filter, and thereby reducing the 

replacement frequency. 

The O&M issues encountered were problems with the chlorine injector, backwash recycle pump, and 

broken inlet and outlet pressure gauges, recycle meter, and backwash totalizer due to unusually cold 

weather in late November. A minimal amount of unscheduled downtime was necessary to repair system 

components. The actual downtime was not calculated due to the lack of an hour meter until November 4, 

2004, but estimated to be no more than 1-2%. 

The simplicity of system operation and operator skill requirements are discussed according to pre- and 

post-treatment requirements, levels of system automation, operator skill requirements, preventative 

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

Pre- and Post-Treatment Requirements. Although not required for treatment, NaOCl was injected 

upstream of the system for disinfection. The prechlorination system was used to provide chlorine 

residuals in water through the adsorption vessels and the distribution system. As such, post-treatment was 

not required at the site. 

System Automation. The APU-100 system is equipped with an automatic backwash control to initiate 

backwash automatically by timer and/or Δp. However, the system experienced several unscheduled 

backwashes from June through September, 2004 as discussed above. Due to the needs for the study such 

20
as filling up logs and collecting backwash samples, the automated backwash control was disabled to allow 

manual backwashes. The system also can recycle the backwash water automatically. 

Operator Skill Requirements. Under normal operating conditions, the skill requirements to operate the 

APU-100 system were minimal. The daily demand on the operator was typically 20 minutes for visual 

inspection of the system and recording of operational parameters on the log sheets. On days when the 

system was backwashed, the operator typically spent approximately two hours on site to complete this 

process. However, if the system was set on automatic backwash, it would not require the operator to be 

present. The operation of the system did not appear to require additional skills beyond those necessary to 

operate the existing water supply equipment. One operator had a Level 4 Distribution Grade and a 

Level 4 Treatment Grade, and the other had a Level 4 Distribution Grade and a Level 3 Treatment Grade. 

Preventative Maintenance Activities. Preventative maintenance tasks recommended by AdEdge included 

daily system inspection and weekly monitoring of the pressure, Δp, and backwash recycle tank level (if 

applicable). Also recommended were the checking of the flowrate, throughput, visual clarity of the 

treated water, bag filters, and performance (i.e. via sample analysis) monthly and the Y-strainers (for 

sediment capture) quarterly. The bag filter before the backwash recycle tank needed replacement after 

every backwash event. All system components were maintained according to the O&M Manual. 

Chemical/Media Handling and Inventory Requirements. Chemical use was not required beyond the 

chlorination system for disinfection. NaOCl consumption varied, but was typically dosed to achieve a 

chlorine residual of 0.3-0.4 mg/L. The chlorine tank was refilled on an as-needed basis. 

4.5 System Performance 

The performance of the APU-100 system was evaluated based on analyses of water samples collected 

from the treatment plant, media backwashing, and distribution system. 

4.5.1 Treatment Plant Sampling. Water samples were collected at three locations throughout the 

treatment train: the inlet (IN), the effluent of the lead vessel (TA), and the effluent of the lag vessel (TB). 

The treatment plant water was sampled on 22 occasions (including two events with duplicate samples 

taken) during the first six months of system operation, with field speciation performed on six of the 22 

occasions. Table 4-7 summarizes the analytical results of critical constituents including arsenic, iron, and 

manganese. On-site water quality measurements including pH, temperature, DO, and ORP were performed at IN, after prechlorination (AC), TA, and TB locations. Chlorine residuals also were measured at 

AC, TA, and TB locations. Table 4-8 summarizes the results of the other water quality parameters. 

Appendix B contains a complete set of analytical results through the first six months of system operation. 

The results of the water samples collected throughout the treatment plant are discussed below. 

Arsenic. Total As concentrations in the raw water ranged from 48.3 to 81.4 μg/L and averaged 61.0 μg/L 

(Table 4-7). As(V) was the predominating species, ranging from 48.0 to 63.2 μg/L and averaging 57.3 

μg/L. Only trace amounts of particulate As and As(III) existed, with average concentrations of 0.9 and 

1.5 μg/L, respectively. Figure 4-7 contains bar charts presenting the concentrations of total As, 

particulate As, As(III), and As(V) at the IN, TA, and TB locations for each speciation sampling event. 

The arsenic concentrations measured during this six-month period were consistent with those in the raw 

water sample collected on October 22, 2003 (Table 4-1). 

The key parameter for evaluating the effectiveness of the APU-100 system was the arsenic concentration 

in the treated water. The arsenic breakthrough curve in Figure 4-8 indicates that the lead vessel (TA) 

removed the majority of arsenic (existing predominantly as As[V]) in the influent water, leaving only 0.7 

21
to 3.0 μg/L to be further polished by the lag vessel. The treated water from the lag vessel contained only 

0.2 to 1.3 μg/L of total arsenic. By the end of the first six months of system operation, the APU-100 

system treated approximately 25,000 BV of water (equivalent to 4,109,000 gallons of water), which was 

about 38% of the vendor-estimated working capacity (66,000 BV as shown in Table 4-4). It must be 

noted, however, that the treatment system was operating with a reduced flowrate and a longer EBCT than 

was originally designed, which might increase the removal capacity of the media. 

As shown in Figure 4-7 and Table 4-7, the particulate As concentrations at the TA and TB locations were 

less than 0.3 μg/L. The average As(III) concentrations were 1.5, 1.4, and 0.7 μg/L at IN, TA, and TB, 

respectively, indicating little or no As(III) removal by the AD-33TM media. It is not clear why up to 2.7 

and 1.3 μg/L of As(III) were measured at TA and TB even in the presence of at least 0.2 mg/L (as Cl2) of 

free chlorine. 

Iron and Manganese. Average concentrations of Fe and Mn were near and/or below the respective 

detection limits throughout the treatment system. Total Fe concentrations were <25 μg/L for all samples 

(Table 4-7) except for five exceedances, including one on July 21 (i.e., 47.3 μg/L in TB), three on 

September 22 (i.e., 127, 27, and 56 μg/L in IN, TA, and TB, respectively), and one on October 27 (27 

μg/L in TA). Dissolved Fe concentrations were <25 μg/L for all samples. Total Mn levels ranged from 

<0.1 to 1.6 μg/L (Table 4-7), with the majority being dissolved Mn. The average total Mn concentrations 

were 0.5, 0.2, and 0.2 μg/L at IN, TA, and TB, respectively. The reduction of total Mn between IN and 

TA and TB indicates some removal of Mn within the adsorption vessels. 

Other Water Quality Parameters. In addition As, Fe, and Mn, other water quality parameters were 

analyzed to provide insight into the chemical processes occurring within the treatment system. The inlet 

pH values ranged from 6.9 to 7.1, which were the lowest among the 12 Round 1 demonstration sites 

(Table 1-1). This near neutral pH condition is desirable for adsorptive media which, in general, have a 

greater arsenic removal capacity when treating lower-pH water. 

The residual chlorine levels measured at the TA and TB locations were comparable to those measured at 

the AC location, indicating little or no chlorine consumption through the AD-33TM vessels. ORP readings 

at the IN location ranged from 148 to 510 mV. Due to the presence of residual chlorine at the AC, TA, 

and TB locations, the respective ORP readings increased to the range of 491 to 710 mV. With DO 

concentrations ranging from 3.3 to 4.7 mg/L, the inlet water was oxidizing, thus explaining why little or 

no As(III) was present in the raw water. 

The results for alkalinity, fluoride, sulfate, silica, and nitrate remained fairly constant throughout the 

treatment train. Orthophosphate (as PO4) was always below the detection limit for all samples. The total 

hardness results ranged from 287 to 397 mg/L as CaCO3, consisting approximately 60% of calcium 

hardness and 40% of magnesium hardness. Hardness did not appear to be affected by the treatment 

process. 

4.5.2 Backwash Water Sampling. The analytical results of the two backwash water sampling 

events are summarized in Table 4-9. Both sampling events showed similar results for soluble As, Fe, and 

Mn. The arsenic concentrations in the backwash water from both vessels were lower than those in the 

raw water used for backwash, indicating some arsenic removal by the media during backwash. The 

backwash water from Vessel A contained much higher arsenic levels (e.g., 48 μg/L) than those from 

Vessel B (e.g., <3 μg/L) most likely due to the fact that the media in Vessel A had a more reduced 

adsorptive capacity than Vessel B. The pH of the backwash water was similar to that of the raw water. 

Turbidity readings from Vessel A were higher than those from Vessel B, most likely because the lead 

tank had removed the majority of particulates from the raw water. 

22
Table 4-7. Summary of Arsenic, Iron, and Manganese Analytical Results 

Parameter 

Sampling 

Location Unit Count Minimum Maximum Average 

Standard 

Deviation

IN μg/L 24 48.3 81.4 61.0 10.2 

As (total) TA μg/L 24 0.7 3.0 1.4 0.6 

TB μg/L 24 0.2 1.3 0.5 0.3 

IN μg/L 6 50.2 65.0 58.8 4.9 

As (soluble) TA μg/L 6 0.9 3.0 1.9 1.0 

TB μg/L 6 0.3 1.2 0.6 0.3 

IN μg/L 6 0.1 3.5 0.9 1.3 

As (particulate) TA μg/L 6 0.1 0.3 0.1 0.1 

TB μg/L 6 0.1 0.3 0.2 0.1 

IN μg/L 6 0.8 2.2 1.5 0.6 

As(III) TA μg/L 6 0.6 2.7 1.4 0.8 

TB μg/L 6 0.2 1.3 0.7 0.4 

IN μg/L 6 48.0 63.2 57.3 5.0 

As(V) TA μg/L 6 0.1 1.7 0.5 0.6 

TB μg/L 6 0.1 0.5 0.1 0.2 

IN μg/L 24 <25 127 <25 23.4 

Total Fe TA μg/L 24 <25 31.1 <25 4.7 

TB μg/L 24 <25 56.0 <25 11.1 

IN μg/L 6 <25 <25 <25 0.0 

Dissolved Fe TA μg/L 6 <25 <25 <25 0.0 

TB μg/L 6 <25 <25 <25 0.0 

IN μg/L 24 <0.1 1.6 0.5 0.4 

Total Mn TA μg/L 24 <0.1 1.2 0.2 0.3 

TB μg/L 24 <0.1 0.9 0.2 0.3 

IN μg/L 6 0.1 1.1 0.6 0.4 

Dissolved Mn TA μg/L 6 <0.1 0.7 0.2 0.3 

TB μg/L 6 <0.1 0.6 0.2 0.2 

One-half of the detection limit was used for nondetect samples for calculations. 

Duplicate samples were included in the calculations. 

Table 4-8. Summary of Water Quality Parameter Measurements 

Parameter 

Sampling 

Location Unit Count Minimum Maximum Average 

Standard 

Deviation

IN mg/L 24 330 390 370 12.8 

Alkalinity TA mg/L 24 345 386 372 8.3 

TB mg/L 24 351 395 373 10.6 

IN mg/L 6 0.3 0.4 0.35 0.05 

Fluoride TA mg/L 6 0.3 0.5 0.35 0.08 

TB mg/L 6 0.3 0.4 0.32 0.04 

IN mg/L 6 8.9 10 9.6 0.4 

Sulfate TA mg/L 6 8.8 10 9.4 0.4 

TB mg/L 6 8.7 10 9.4 0.6 

23
Table 4-8. Summary of Water Quality Parameter Measurements (Continued) 

Parameter 

Sampling 

Location Unit Count Minimum Maximum Average 

Standard 

Deviation

IN mg/L 24 <0.06 0.05 0.04 0.01 

TA mg/L 24 <0.06 0.05 0.04 0.01 Orthophosphate 

(as PO4) TB mg/L 24 <0.06 0.05 0.04 0.01 

IN mg/L 24 24.0 26.7 25.5 0.6 

Silica TA mg/L 24 24.3 27.2 25.4 0.6 

TB mg/L 24 23.9 26.9 25.2 0.7 

IN mg/L 6 0.2 0.3 0.22 0.04 

Nitrate (as N) TA mg/L 6 0.2 0.3 0.22 0.04 

TB mg/L 6 0.2 0.3 0.22 0.04 

IN NTU 24 <0.1 0.6 0.2 0.2 

Turbidity TA NTU 24 <0.1 0.5 0.2 0.1 

TB NTU 24 <0.1 0.9 0.3 0.2 

IN S.U. 21 6.9 7.1 7.0 0.1 

AC S.U. 21 6.9 7.6 7.1 0.2 

TA S.U. 21 6.9 7.1 7.0 0.1 pH 

TB S.U. 21 6.8 7.1 7.0 0.1 

IN oC 21 19.5 26.1 21.6 1.6 

AC oC 21 19.8 24.5 21.4 1.2 

TA oC 21 19.7 26.7 21.5 1.5 Temperature 

TB oC 21 19.7 24.0 21.5 1.2 

IN mg/L 21 3.3 4.7 4.0 0.3 

AC mg/L 21 3.2 6.8 4.8 1.1 

TA mg/L 21 3.5 6.6 4.1 0.8 Dissolved Oxygen 

TB mg/L 21 3.4 6.9 4.1 0.8 

IN mV 21 148 510 304 132 

AC mV 21 491 642 594 36 

TA mV 21 565 681 623 30 

ORP 

TB mV 21 590 710 637 31 

AC mg/L 21 0.2 0.5 0.4 0.1 

Free Chlorine TA mg/L 21 0.2 0.5 0.4 0.1 

TB mg/L 21 0.2 0.4 0.3 0.1 

AC mg/L 21 0.2 0.7 0.4 0.1 

Total Chlorine TA mg/L 21 0.2 0.6 0.4 0.1 

TB mg/L 21 0.2 0.6 0.4 0.1 

IN mg/L 6 287 384 337 37 

TA mg/L 6 298 397 349 37 Total Hardness 

(as CaCO3) TB mg/L 6 299 377 341 28 

IN mg/L 6 171 241 201 25 

TA mg/L 6 175 236 206 26 Ca Hardness 

 (as CaCO3) TB mg/L 6 174 235 202 22 

IN mg/L 6 116 152 136 14 

TA mg/L 6 123 161 142 13 Mg Hardness 

 (as CaCO3) TB mg/L 6 124 149 139 10 

One-half of the detection limit was used for nondetect samples for calculations. 

Duplicate samples were included in the calculations. 

24
Arsenic Species at the Inlet (IN)

0

10

20

30

40

50

60

70

6/30/2004 7/28/2004 8/25/2004 9/22/2004 10/20/2004 12/15/2004

Date

As Concentration (μg/L)

As (particulate)

As (V)

As (III)

Arsenic Species after Vessel A (TA)

0

10

20

30

40

50

60

70

6/30/2004 7/28/2004 8/25/2004 9/22/2004 10/20/2004 12/15/2004

Date

As Concentration (μg/L)

As (particulate)

As (V)

As (III)

Arsenic Species after Vessel B (TB)

0

10

20

30

40

50

60

70

6/30/2004 7/28/2004 8/25/2004 9/22/2004 10/20/2004 12/15/2004

Date

As Concentration (μg/L)

As (particulate)

As (V)

As (III)

Figure 4-7. Concentration of Arsenic Species at the Inlet, after 

Vessel A, and after Vessel B 

25
26

0

10

20

30

0 5 10 15

Bed Volumes of Water Treated (*103

)

As Concentration 40

50

60

70

80

90

20 25

 (μg/L)

Inlet

Vessel A

Vessel B

Figure 4-8. Total Arsenic Breakthrough Curve 

Table 4-9. Backwash Water Sampling Results 

Vessel A Vessel B 

Sampling Event 

pH Turbidity TDS Soluble As Soluble Fe Soluble Mn pH Turbidity TDS Soluble As Soluble Fe Soluble Mn 

No. Date S.U. NTU mg/L μg/L μg/L μg/L S.U. NTU mg/L μg/L μg/L μg/L

1 10/20/2004 7.3 22 486 48.2 <25 0.1 7.3 6.5 442 2.7 <25 0.1 

2 12/15/2004 7.1 45 358 48.0 <25 0.4 7.1 25 306 1.6 <25 <0.1

4.5.3 Distribution System Water Sampling. The results of the distribution system sampling are 

summarized in Table 4-10. The most noticeable change in the distribution samples since the system 

began opeartion was a decrease in arsenic concentrations, with an exception for the August 26, 2004 DS3 

sample. Average baseline arsenic concentrations were 55.2, 44.6, and 46.6 μg/L at DS1, DS2, and DS3, 

respectively, and ranged from 20.8 to 80.1 μg/L. After the performance evaluation began, average 

concentrations at DS1, DS2, and DS3 were 18.8, 20.1, and 21.8 μg/L, respectively, and ranged from 9.3 

to 28.5 μg/L (with an exception for the August 26, 2004 DS3 sample). The arsenic concentrations in the 

distribution system were higher than those in the system effluent, presumably due to the blending of the 
Table 4-10. Distribution System Sampling Results

Sampling

DS1 DS2 

4125 E. Shade Road 4095 E. Goldmine(a) 40

Non-LCR Non-LCR 

1st Draw 1st Draw 

Event 

Stagnation Time 

pH 

Alkalinity

As 

Fe 

Mn 

Pb 

Cu 

Stagnation Time 

pH 

Alkalinity

As 

Fe 

Mn 

Pb 

Cu 

Stagnation Time 

pH 

Alkalinity

No. Date hrs S.U. mg/L μg/L μg/L μg/L μg/L μg/L hrs S.U. mg/L μg/L μg/L μg/L μg/L μg/L hrs S.U. mg/L μ

BL1 12/17/03 12.0 7.1 387 38.5 <25 1.2 2.3 119 7.0 7.2 405 20.8 182 68.4 1.6 106 8.5 7.2 407 3BL2 01/06/04 14.0 8.9 411 49.3 <25 0.8 0.5 24.2 11.3 8.5 407 48.4 <25 0.6 2.4 64.0 6.0 8.2 419 4BL3 01/21/04 34.0 7.2 367 80.1 <25 0.2 1.2 24.0 11.0 7.2 371 57.0 <25 0.3 3.8 128 7.8 7.1 336 4BL4 02/05/04 23.0 7.1 394 52.8 46.1 0.5 0.5 31.3 9.8 7.1 406 52.2 40.2 0.2 0.8 34.4 7.0 7.1 406 5

1 07/28/04(b) 11.0 7.2 373 11.7 <25 <0.1 4.4 147 Homeowner was unavailable 5.3 7.2 413 22 08/26/04(b) 20.5 6.9 379 15.4 <25 0.3 4.8 112 10.0 6.9 395 28.5 <25 0.3 4.3 66.7 7.5 6.9 395 43 09/22/04(c) 12.0 7.2 402 18.0 <25 1.3 4.4 194 10.5 6.9 373 9.3 <25 0.3 2.9 33.8 7.3 7.0 381 24 10/20/04 19.0 6.7 406 22.9 <25 0.4 2.9 99.6 9.0 6.9 410 19.8 <25 3.0 7.0 129 6.5 7.0 394 25 11/17/04 7.5 7.0 418 21.2 <25 0.4 1.4 79.5 Homeowner was unavailable 6.3 7.1 418 16 12/15/04(b) 9.0 7.1 370 15.0 <25 0.7 4.1 52.5 9.0 7.2 403 21.8 <25 1.1 6.6 139 9.0 7.2 394 

(a) Sample DS2 was taken from 4055 E. Goldmine Rd on December 17, 2003. (b) Sample DS1 was collected on the previous day.(c) Sample DS1 was taken on September 30, 2004 when homeowner returned from vacation; pH was analyzed out of hold time. Lead action level = 15 μg/L; copper action level = 1.3 mg/L. BL = Baseline Sampling. 

27
treated water (supplied by Well No. 2) with untreated water from Well No. 3 and other wells, which also 

contained arsenic (Table 4-1). 

Lead concentrations ranged from 0.5 to 7.0 μg/L, with none of the samples exceeding the action level of 

15 μg/L. Copper concentrations ranged from 24.0 to 194 μg/L, with no samples exceeding the 1,300 

μg/L action level. Due to the blending of water from untreated wells, it was inconclusive whether the Pb 

or Cu concentrations in the distribution system had been affected by the arsenic treatment system. 

Measured pH values ranged from 6.7 to 7.2, except for the baseline pH analyses performed on January 6, 

2004. Alkalinity levels ranged from 336 to 419 mg/L (as CaCO3). Iron concentrations ranged from <25 

to 182 μg/L, with concentrations in the majority of the samples at <25 μg/L. Since the system became 

operational, iron concentrations in the distribution system samples were consistently below the detection 

limit. The concentrations of Mn in the distribution system samples were ≤ 3.0 μg/L, except for the first 

baseline sample at DS2. Mn levels do not appear to have been affected since the system began to operate. 

4.6 System Costs 

The cost-effectiveness 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 gallons of water treated. Capital costs included equipment, 

engineering, and installation, and O&M costs included media replacement and disposal, chemical supply, 

electrical power use, and labor. 

4.6.1 Capital Costs. The capital investment costs for equipment, site engineering, and installation 

were $90,757 (see Table 4-11) as provided by the AdEdge in a cost proposal to Battelle dated September 

9, 2003. The equipment costs were $66,235 (or 73% of the total capital investment), which included 

costs for two FRP treatment vessels, 54 ft3

 of AD-33TM media ($245/ft3 or $8.73/lb), piping and valves, 

instrumentation and controls, field services (including operator training, technical support, and system 

shakedown), miscellaneous materials and supplies, and a change order for system reconfiguration from 

parallel to series operation. 

The engineering costs included the costs for preparation of the engineering plans, system layout and 

footprint, drawings of site and piping plans, and equipment cut sheets for the permit application submittal 

(Section 4.3.1). The costs also included resubmission of the redesigned system layout and piping plans to 

ADEQ for approval. The engineering costs were $11,372, which was 13% of the total capital investment. 

The installation costs included the costs for the equipment and labor to unload and install the APU-100 

system, perform the piping tie-ins and electrical work, load and backwash the media, and reconfigure the 

system (Section 4.3.2). The installation was performed by AdEdge and its subcontractor, Fann 

Environmental. The installation costs were $13,150, or 14% of the total capital investment. 

The costs associated with the backwash recycle system were not reflected in the capital investment shown 

in Table 4-11. AWC contracted AdEdge to design and install the backwash recycle system for handling 

the backwash water. The total cost for the backwash recycle system was $11,546, including material, 

engineering, and installation costs. 

AWC installed a sun shed structure with a galvanized steel frame over the APU-100 system (Section 

4.3.3). The 12 ft × 15 ft structure has a height of 9.5 ft and is mounted on a 12 ft × 15 ft concrete pad. 

The structure was pre-engineered to sustain a 90-mph wind load and a 30-lb/ft2

 snow load. The total cost 

for the building was $13,677 which included $3,500 for materials and labor to assemble the structure. 

28
Table 4-11. Summary of Capital Investment Costs

Description Quantity Cost 

% of Capital 

Investment Cost 

Equipment Costs

Adsorptive Media Vessels 2 $21,800 – 

AD-33TM Media 54 ft3 $13,230 – 

Piping and Valves 1 $7,520 – 

Instrumentation and Controls 1 $4,575 – 

O&M Manual, Operator Training, Technical Support 1 $3,800 – 

Procurement, Assembly, Labor, Shakedown 1 $12,575 – 

Freight Costs 1 $1,855 – 

Change Order for System Reconfiguration 1 $880 – 

Equipment Total – $66,235 73% 

Engineering Costs

Materials, Submittals, FedEx, Postage, Supplies 1 $75 – 

AdEdge PM Oversight, Specification Preparation 1 $3,420 – 

Design, Drawings, Coordination 1 $4,970 – 

Review Meeting, Airfare, Lodging and Meals 1 $1,017 – 

Change Order for System Reconfiguration – $1,890 – 

Engineering Total – $11,372 13% 

Installation Costs

Subcontractor 1 $6,750 – 

Vendor Labor 4 days $3,040 – 

Vendor Travel 4 days $1,290 – 

Change order for System Reconfiguration – $2,070 – 

Installation Total – $13,150 14% 

Total Capital Investment(a) – $90,757 100% 

(a) Estimated costs of $11,546 for a backwash recycle system not included. 

The total capital cost of $90,757 and equipment cost of $66,235 were converted to a unit cost of 

$0.13/1,000 gallon and $0.09/1,000 gallon, respectively, using a capital recovery factor of 0.06722 based 

on a 3% interest rate and a 20-year return period (Chen et al., 2004). These calculations assumed that the 

system operated 24 hours a day, 7 days a week at the system design flowrate of 90 gpm. The system 

operated only 12 hours a day at approximately 31.5 gpm (see Table 4-5), producing 4,109,000 gallons of 

water during the six-month period, so the total unit cost and equipment-only unit cost were increased to 

$0.74/1,000 gallon and $0.54/1,000 gallon, respectively, at this reduced usage rate. Using the system’s 

rated capacity of 45 gpm (or 64,800 gpd), the capital cost was $2,017/gpm (or $1.40/gpd) and the 

equipment-only cost was $1,472/gpm (or $1.02/gpd). These calculations did not include the cost of the 

building construction. 

4.6.2 Operation and Maintenance Costs. O&M costs included only incremental costs associated 

with the APU-100 system, such as media replacement and disposal, chemical supply, electricity, and 

labor (Table 4-12). Because media replacement and disposal did not take place during the first six 

months of operation, its cost per 1,000 gallons of water treated was calculated as a function of the 

projected media run length using the vendor-estimated $9,940 for one vessel’s media changeout. The 

cost included new media for one vessel, freight, labor, travel expenses, and spent media testing and 

disposal. At the vendor estimated media capacity of 66,000 BV (see Table 4-4) or a throughput of 10,861 

kgal, the unit O&M cost is projected to be $1.27/1,000 gallons of water treated including the estimated 

29
Table 4-12. Summary of O&M Costs 

Cost Category Value Assumptions 

Volume processed (kgal) 4,109 From 06/24/04 to 12/22/04 

Media Replacement and Disposal

Media cost ($/ft3) $245 Vendor quote 

Total media volume (ft3) 22 One vessel 

Media replacement cost ($) $5,390 Vendor quote 

Freight ($) $465 Vendor quote for delivery 

Labor cost ($) $3,840 Vendor quote includes disposal 

Waste Analysis ($) $245 Vendor quote for one TCLP test 

Subtotal $9,940 Vendor quote 

Media replacement and disposal cost 

($/1,000 gal) See Figure 4-9 

Based upon media run length at 10-μg/L 

arsenic breakthrough 

Chemical Usage

Chemical cost ($) $0.000 No additional chemicals required 

Electricity

Electric utility charge ($/kWh) $0.089 Rate provided by AWC 

Usage (kWh) 377 – 

Total electricity cost ($) $33.52 – 

Electricity cost ($/1,000 gal) $0.008 – 

Labor

Average weekly labor (hrs) 2.6 20-30 minutes/day 

Labor cost ($/1,000 gal) $0.35 Labor rate = $21/hr 

Total O&M cost ($/1,000 gal) See Figure 4-9 

Based upon media run length at 10-μg/L 

arsenic breakthrough 

media replacement and disposal cost ($0.92/1,000 gallons) and chemical supply, electricity, and labor 

costs ($0.36/1,000 gallons) (Figure 4-9). The projected media replacement and disposal cost will be 

refined once the actual throughput and cost at the time of the media replacement become available. 

The only chemical cost was the use of NaOCl for disinfection. Because the APU-100 system did not 

appear to consume any chlorine, the incremental chemical cost was negligible. 

Incremental electrical power consumption was calculated based on the electric meter readings for one day 

(12 hours) of system operation. This usage rate was approximately 2.07 kWh per day and included 

electrical consumption by the recycle pump. Therefore, the electricity cost was $0.008/1,000 gallons of 

water treated. 

The routine, non-demonstration related labor activities (Section 4.4.4) in addition to preventative 

maintenance activities and repairs consumed 20-30 minutes per day. Based on this time commitment and 

a labor rate of $21/hr, the labor cost was $0.35/1,000 gallons of water treated. 

30
$0.00

$0.25

$0.50

$0.75

$1.00

$1.25

$1.50

$1.75

$2.00

$2.25

$2.50

$2.75

$3.00

$3.25

$3.50

$3.75

$4.00

$4.25

$4.50

$4.75

$5.00

0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150

Media Working Capacity, Bed Volumes (x1000)

Cost ($/1,000 gal)

O&M cost

Media replacement cost

Vendor-estimated 

media capacity of 

66,000 BV

Figure 4-9. Media Replacement and O&M Costs for the Rimrock Treatment System 

31
5.0 REFERENCES 

AdEdge. 2004. Operation and Maintenance Manual, APU Adsorption Package Units for Arsenic and 

Heavy Metals Removal, Rimrock,Arizona (Montezuma Haven Wells). April. 

Arizona Water Company (AWC). 2004. AWC Consumer Confidence (Water Quality) Reports: “2003 

Annual Water Quality Report for Rimrock, Arizona PWSID# 13-046.” Available at: 

http://www.azwater.com/ccr-rr04.pdf. 

Battelle. 2003. Revised Quality Assurance Project Plan for Evaluation of Arsenic Removal Technology. 

Prepared under Contract No. 68-C-00-185, Task Order No. 0019, for U.S. EPA NRMRL. 

November 17. 

Battelle. 2004. Final System Performance Evaluation Study Plan: U.S. EPA Demonstration of Arsenic 

Removal Technology at Rimrock, Arizona. Prepared under Contract No. 68-C-00-185, Task 

Order No. 0019 for U.S. EPA NRMRL. February 12. 

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. Prepared for U.S. EPA NRMRL, 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 (March): 103-113. 

Oxenham, J., Chen, A.S.C., L. Wang. 2005. Arsenic Removal from Drinking Water by Adsorptive 

Media, USEPA Demonstration Project at Rollinsford, NH, Six-Month Evaluation Report. 

Prepared under Contract No. 68-C-00-185, Task Order No. 0019 for U.S. EPA NRMRL. 

September. 

U.S. Environmental Protection Agency (EPA). 2001. National Primary Drinking Water Regulations: 

Arsenic and Clarifications to Compliance and New Source Contaminants Monitoring. Fed. 

Register, 66:14:6975. January 22. 

U.S. Environmental Protection Agency (EPA). 2002. Lead and Copper Monitoring and Reporting 

Guidance for Public Water Systems. Prepared by U.S. EPA's Office of Water. EPA/816/R02/009. February. 

U.S. Environmental Protection Agency (EPA). 2003. Minor Clarification of the National Primary 

Drinking Water Regulation for Arsenic. Federal Register, 40 CFR Part 141. March 25. 

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. EPA 

NRMRL, Cincinnati, OH. 

32
APPENDIX A 

OPERATIONAL DATA
EPA Arsenic Demonstration Project at Rimrock, AZ - Daily System Operation Log Sheet 

Daily System Operation 

Week 

No. Date & Time Run Time

Tank Position Vessel A Flow Meter Vessel B Flow Meter ΔP Pressure

Maste

Totalize

Lead Lag

Flow

rate Totalizer

Flow

rate

Bed 

Volume

Flowr

ate Totalizer

Flow

rate

Bed 

Volume Vessel A Vessel B Inlet

Between 

Tanks Outlet

hr A/B A/B gpm gal gpm gpm gal gpm psi psi psig psig psig gal 

1 6/24/04 12:32 NA A B 28 23971 NA NA 27 23294 NA NA 4 3.5 105 104 100+ 7866

6/25/04 11:30 11.0 A B 33 44991 31.9 128 31 44375 32.0 128 5.5 5 98 95 92 7886

2

6/28/04 9:17 33.8 A B 32 108441 31.3 513 32 108075 31.4 515 5.5 5 100 96 93 79476/29/04 9:19 12.0 A B 29 131386 31.8 653 28 130974 31.7 654 4.5 4 105 103 100+ 7969

6/30/04 16:01 18.7 A B 30 166117 31.0 864 30 165692 30.9 865 5 5 101 100 90 8003

7/1/04 13:59 10.0 A B 31 185223 31.9 980 30 184858 32.1 982 5.5 5 100 96 93 80217/2/04 14:56 12.9 A B 32 209871 31.7 1130 31 209636 31.9 1132 5.5 5 100 96 94 8045

3

7/6/04 13:30 46.6 A B 29 297899 31.5 1665 28 297866 31.6 1669 4 4 105 109 100+ 8131

7/7/04 9:00 7.5 A B 32 312011 31.4 1750 33 311809 31.0 1753 5.5 4.5 100 95 94 8144

7/8/04 16:32 19.5 A B 32 348968 31.5 1975 32 349009 31.7 1979 5 5 100 97 93 81807/9/04 13:35 9.0 A B 31 365938 31.3 2078 31 366086 31.4 2083 5 5 100 97 94 8197

4

7/12/04 13:30 35.9 A B 32 433271 31.2 2487 31 433584 31.3 2493 5 5 100 96 92 82627/13/04 10:00 8.5 A B 32 449425 31.7 2585 32 449865 31.9 2592 5 5 100 95 93 8278

7/14/04 9:30 11.5 A B 32 470700 30.8 2715 32 471247 31.0 2722 5.5 5 100 93 92 8298

7/15/04 13:30 16.0 A B 30 500630 31.2 2897 31 500527 30.5 2900 4.5 4.5 101 100 87 83277/16/04 14:25 12.9 A B 27 525019 31.5 3045 27 524715 31.2 3047 3.5 3.5 110 110 100+ 8350

5

7/19/04 9:30 31.1 A B 32 584077 31.7 3404 33 583614 31.6 3405 5.5 5 99 95 92 84077/20/04 8:57 11.4 A B 28 605379 31.0 3533 27 604867 30.9 3534 4 3.5 102 104 104 8428

7/21/04 14:02 17.1 A B 31 637557 31.4 3729 30 637111 31.5 3730 5 4.9 100 97 94 84597/22/04 16:12 14.2 A B 32 664233 31.4 3891 32 663800 31.4 3892 5 5 99 95 93 84857/23/04 14:48 10.6 A B 32 683833 30.8 4010 31 683350 30.7 4011 5 4.5 100 96 94 

6

7/26/04 9:16 30.5 A B 28 740859 31.2 4356 28 740026 31.0 4355 4 4 102 102 101 8558

7/27/04 14:12 16.9 A B 32 772923 31.6 4551 32 772091 31.6 4550 5.9 5 100 95 93 8590

7/28/04 9:46 7.6 A B 33 787316 31.7 4639 32 786508 31.8 4638 5.5 5 100 95 92 86037/29/04 9:01 11.3 A B 30 808295 31.1 4766 30 807403 31.0 4765 5 5 100 96 94 8624

7/30/04 16:18 19.3 A B 31 844137 31.0 4984 31 843320 31.0 4983 5 5 100 96 94 8659

7

8/2/04 10:29 30.2 A B 32 899068 30.3 5318 31 898410 30.4 5318 5 5 100 96 90 8712

8/3/04 9:27 11.0 A B 32 919909 31.7 5444 31 919248 31.7 5445 5 4.5 100 96 90 87328/4/04 9:47 12.3 A B 27 943057 31.3 5585 26 942185 31.0 5584 4 3.6 105 103 96 87558/5/04 8:58 11.2 A B 32 963804 30.9 5711 30 962970 31.0 5710 5 5 100 96 90 8775

8/6/04 14:25 17.4 A B 30 996229 31.0 5908 30 995478 31.0 5908 5 5 100 98 90 8806

8

8/9/04 9:45 31.3 A B 26 1055151 31.3 6266 26 1054232 31.3 6265 3.6 3.6 103 104 99 8863

8/10/04 16:09 18.4 A B 31 1089574 31.2 6475 30 1087899 30.5 6469 5 5 100 98 90 88978/11/04 11:09 7.0 A B 32 1102913 31.8 6557 31 1100798 30.7 6548 5 5 100 97 90 8909

8/12/04 9:19 10.2 A B 32 1122569 32.2 6676 31 1120172 31.8 6666 5 5 100 97 90 8928

8/13/04 17:18 20.0 A B 30 1160528 31.7 6907 30 1157685 31.3 6893 5 5 100 97 90 8964

9

8/16/04 9:00 27.7 A B 28 1214460 32.5 7234 26 1210860 32.0 7217 3.8 3.8 105 103 98 9016

8/17/04 12:00 15.0 A B 31 1240824 29.3 7395 30 1236957 29.0 7375 5 4.8 100 98 90 9042

8/18/04 9:00 9.0 A B 28 1259075 33.8 7505 26 1255175 33.7 7486 3.9 3.5 105 103 97 9059

8/19/04 11:30 14.5 A B 29 1284888 29.7 7662 29 1280719 29.4 7641 4 3.9 101 101 96 90848/20/04 15:34 16.1 A B 30 1315490 31.7 7848 31 1310625 31.0 7823 5 5 100 98 90 9113

10

8/23/04 10:18 30.7 A B 32 1375391 32.5 8212 31 1369612 32.0 8181 5 4.5 100 96 90 91708/24/04 12:31 14.2 A B 31 1401393 30.5 8370 30 1395087 29.9 8336 5 4.5 100 96 90 9195

8/25/04 9:12 8.7 A B 31 1418118 32.1 8472 30 1411570 31.6 8436 5 4.5 100 97 90 9211

8/26/04 13:54 16.7 A B 31 1449870 31.7 8665 30 1442950 31.3 8627 5 4.5 100 97 89 92428/27/04 15:31 13.6 A B 31 1475337 31.2 8820 31 1468239 31.0 8781 5 4.6 100 97 90 9266

11

8/30/04 16:13 36.7 A B 27 1544210 31.3 9238 27 1536384 30.9 9195 4 4 104 101 106 93338/31/04 11:17 7.1 A B 31 1557388 31.1 9318 30 1549642 31.3 9275 5 4.7 100 97 90 9345

9/1/04 11:00 11.7 A B 32 1578093 29.5 9444 31 1570127 29.1 9400 5.5 4.8 100 97 90 93659/2/04 13:54 14.9 A B 32 1605790 31.0 9612 32 1597517 30.6 9566 5 5 100 96 89 93929/3/04 12:42 10.8 A B 30 1625872 31.0 9734 30 1617330 30.6 9687 5 5 100 97 90 9412

A-1
EPA Arsenic Demonstration Project at Rimrock, AZ - Daily System Operation Log Sheet 

Daily System Operation (Continued) 

Week 

No. Date & Time Run Time

Tank Position Vessel A Flow Meter Vessel B Flow Meter ΔP Pressure

Maste

Totalize

Lead Lag

Flow

rate Totalizer

Flow

rate

Bed 

Volume

Flowr

ate Totalizer

Flow

rate

Bed 

Volume Vessel A Vessel B Inlet

Between 

Tanks Outlet

hr A/B A/B gpm gal gpm gpm gal gpm psi psi psig psig psig gal 

12

9/6/04 0:00 Holiday

9/7/04 16:52 52.2 A B 30 1723558 31.2 10328 29 1714199 30.9 10275 5 5 100 97 90 95069/8/04 10:57 6.1 A B 31 1734996 31.3 10398 31 1725572 31.2 10344 5 5 100 97 90 95179/9/04 17:29 18.5 A B 31 1769316 30.9 10606 31 1759727 30.7 10552 5 5 100 97 90 9550

9/10/04 16:45 11.3 A B 31 1790558 31.4 10735 31 1780911 31.3 10681 5 5 100 96 90 9571

13

9/13/04 9:43 29.0 A B 27 1844869 31.2 11065 27 1835049 31.1 11010 3.9 3.5 102 103 99 96249/14/04 9:30 11.8 A B 32 1867121 31.5 11200 31 1857243 31.4 11145 5.1 5 100 95 89 96459/15/04 9:30 12.0 A B 31 1889587 31.2 11337 33 1879663 31.1 11281 5.1 5 100 95 90 96679/16/04 8:22 10.9 A B 31 1911446 33.5 11470 31 1901462 33.4 11413 5.5 5 100 96 90 9688

9/17/04 13:30 17.1 A B 31 1944096 31.8 11668 31 1933954 31.6 11611 5.1 5 100 95 90 9720

14

9/20/04 13:00 35.5 A B 31 2011723 31.7 12079 30 2001410 31.7 12021 5 4.9 100 96 91 97859/21/04 10:00 9.0 A B 31 2029216 32.4 12185 30 2018904 32.4 12127 5 4.9 100 96 91 98029/22/04 10:00 12.0 A B 31 2050996 30.3 12318 30 2040690 30.3 12259 5 4.9 100 96 91 9824

9/23/04 9:00 11.0 A B 31 2074455 35.5 12460 30 2064162 35.6 12402 5 4.9 100 96 91 9847

9/24/04 11:30 14.5 A B 31 2101154 30.7 12623 30 2090817 30.6 12564 4.9 4.8 100 97 91 9872

15

9/27/04 10:00 34.5 A B 32 2167484 32.0 13026 32 2156478 31.7 12963 5 4.8 100 96 91 99369/28/04 11:34 13.6 A B 31 2192360 30.6 13177 31 2181238 30.4 13113 5 5 100 97 91 99609/29/04 15:10 15.6 A B 31 2221335 31.0 13353 31 2210018 30.7 13288 5 5 100 96 90 99889/30/04 11:16 8.1 A B 31 2236812 31.8 13447 32 2225389 31.6 13382 5 5 100 97 91 1000310/1/04 13:43 14.4 A B 31 2264087 31.5 13613 30 2252590 31.4 13547 5 5 100 97 90 10029

16

10/4/04 0:00 NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA 

10/5/04 10:42 45.0 A B 32 2348918 31.4 14128 31 2337120 31.3 14061 5 5 100 96 90 1011210/6/04 17:31 18.8 A B 29 2383918 31.0 14341 30 2372015 30.9 14273 4.9 4.9 102 100 95 1014610/7/04 10:54 5.4 A B 32 2394302 32.1 14404 31 2382373 32.1 14336 5.2 5 100 96 89 1015

10/8/04 11:38 12.7 A B 31 2417168 29.9 14543 29 2405125 29.8 14474 5.5 5 100 96 89 10178

17

10/11/04 0:00 Holiday

10/12/04 17:29 53.9 A B 27 2515357 30.4 15140 27 2502458 30.1 15065 4 3.5 102 104 99 1027310/13/04 17:41 12.2 A B 26 2538203 31.2 15279 26 2525203 31.1 15204 3.5 3.5 104 107 104 1029610/14/04 18:20 12.7 A B 26 2561400 30.6 15419 27 2548271 30.4 15344 4 4 103 105 100 10318

10/15/04 0:00 NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA 

18

10/18/04 14:49 44.5 A B 31 2644969 31.3 15927 31 2631513 31.2 15850 5 4.6 100 98 92 1039910/19/04 15:01 12.2 A B 31 2667528 30.8 16064 32 2654020 30.7 15986 5.1 5 100 97 91 1042110/20/04 10:35 7.6 A B 31 2682128 32.2 16153 31 2667888 30.5 16071 5.1 4.9 100 97 91 10434

10/21/04 0:00 NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA 

10/22/04 12:02 25.5 A B 32 2730730 31.8 16448 28 2716319 31.7 16365 5 5 100 97 91 10482

19

10/25/04 10:46 34.7 A B 31 2796639 31.6 16849 31 2781672 31.4 16762 5 5 100 96 100 1054610/26/04 15:02 16.3 A B 31 2827402 31.5 17036 32 2811839 30.9 16945 5.4 5 100 97 90 1057510/27/04 10:00 7.0 A B 31 2840201 30.6 17114 30 2824366 30.0 17022 5 5 100 96 90 1058810/28/04 10:32 12.5 A B 27 2864858 32.8 17264 29 2848575 32.2 17169 4 3.6 109 105 100 1061110/29/04 14:18 15.8 A B 32 2895024 31.9 17447 31 2878185 31.3 17349 4.6 4.6 100 98 93 10640

20

11/1/04 15:10 36.9 A B 31 2966104 32.1 17879 32 2948057 31.6 17773 5.5 5.1 100 96 90 1070911/2/04 11:50 8.7 A B 29 2982700 31.9 17980 29 2964350 31.3 17872 4 4 105 101 96 10725

11/3/04 9:45 9.9 A B 31 3002182 32.7 18098 32 2983630 32.4 17989 5.1 5 100 98 98 10744

11/4/04 14:56 17.2 A B 32 3033540 30.4 18289 32 3014434 29.9 18177 5 5 100 98 99 1077411/5/04 12:36 9.7 A B 32 3052755 33.4 18405 30 3033038 32.3 18290 5.1 5 100 97 98 10792

21

11/8/04 11:09 34.5 A B 33 3120094 32.7 18815 31 3099099 32.1 18691 5.5 5 100 98 99 1085611/9/04 11:19 12.2 A B 32 3143725 30.8 18958 31 3122431 30.4 18833 5.5 5 100 97 98 10879

11/10/04 16:57 17.6 A B 32 3177995 32.1 19166 32 3156140 31.6 19038 5.5 5 101 96 98 10912

11/11/04 0:00 Holiday

11/12/04 17:15 24.3 A B 31 3225113 32.3 19453 33 3202655 31.9 19320 5.5 5 100 96 97 10957

A-2
EPA Arsenic Demonstration Project at Rimrock, AZ - Daily System Operation Log Sheet 

Daily System Operation (Continued) 

Week 

No. Date & Time Run Time

Tank Position Vessel A Flow Meter Vessel B Flow Meter ΔP Pressure

Maste

Totalize

Lead Lag

Flow

rate Totalizer

Flow

rate

Bed 

Volume

Flowr

ate Totalizer

Flow

rate

Bed 

Volume Vessel A Vessel B Inlet

Between 

Tanks Outlet

hr A/B A/B gpm gal gpm gpm gal gpm psi psi psig psig psig gal 

22

11/15/04 18:03 37.1 A B 30 3296170 31.9 19885 33 3272583 31.4 19745 5 5 101 99 100 1102611/16/04 10:12 4.5 A B 32 3304356 30.3 19934 31 3280723 30.1 19795 5.9 5.1 100 97 97 11034

11/17/04 9:46 11.0 A B 32 3326877 34.1 20071 28 3303126 33.9 19931 5.5 5 101 98 99 11055

11/18/04 14:49 17.4 A B 32 3359732 31.5 20271 33 3335681 31.2 20129 5.9 5 101 97 97 1108711/19/04 15:40 12.7 A B 31 3384711 32.8 20423 32 3360410 32.5 20279 5.5 5 101 99 99 11111

23

11/22/04 9:38 30.5 A B 32 3443037 31.9 20777 30 3418182 31.6 20630 5.6 5.1 100 97 99 11167

11/23/04 10:00 12.5 A B 33 3466574 31.4 20920 33 3441496 31.1 20772 5.5 5 101 98 98 1119011/24/04 14:11 13.0 A B 31 3492632 33.4 21078 31 3467298 33.1 20929 5.5 5 101 97 98 11215

11/25/04 0:00 Holiday 11/26/04 0:00

24

11/29/04 10:14 58.4 A B 30 3605433 32.2 21764 30 3579122 31.9 21608 6 5 122* 97 115 1132511/30/04 10:47 11.0 A B 31 3629181 36.0 21908 32 3602681 35.7 21751 5.5 5 NA 98 NA 11348

12/1/04 10:58 NA A B 32 3652572 NA 22050 33 3625889 NA 21892 5.4 5 NA 97 NA 11370

12/2/04 0:00 NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA 12/3/04 0:00 NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA 

25

12/6/04 9:35 NA A B 33 3766441 NA 22742 33 3738862 NA 22579 5.5 5.5 NA 96 NA 1148112/7/04 9:15 11.9 A B 33 3788938 31.5 22879 31 3761091 31.1 22714 5.5 5 NA 97 NA 11503

12/8/04 10:04 12.3 A B 31 3813731 33.6 23030 32 3785617 33.2 22863 5.5 5 NA 97 NA 11527

12/9/04 9:32 11.6 A B 33 3835866 31.8 23164 33 3807480 31.4 22996 5.5 5.3 NA 97 NA 11548

12/10/04 14:00 13.8 A B 33 3863117 32.9 23330 31 3834341 32.4 23159 6.5 5.5 NA 97 NA 11575

26

12/13/04 8:15 NA A B 33 3927415 NA 23720 34 3897613 NA 23544 5.5 5 NA 98 NA 11636

12/14/04 14:00 NA A B 33 3957724 NA 23905 33 3927319 NA 23724 5.5 5.1 NA 98 NA 1166612/15/04 17:00 NA A B NA 3982673 NA 24056 NA 3950999 NA 23868 NA NA NA 85 NA 1168812/16/04 15:13 13.0 A B 33 4008571 33.2 24214 31 3976384 32.5 24022 6 5.5 NA 97 NA 1171312/17/04 16:39 11.9 A B NA 4032260 33.2 24358 NA 3999641 32.6 24164 NA NA NA NA NA 11735

27

12/20/04 17:14 35.7 A B NA 4103115 33.1 24788 NA 4068989 32.4 24585 NA NA NA NA NA 11803

12/21/04 9:24 NA A B 32 4122253 NA 24904 33 4087888 NA 24700 5.5 5 NA 97 NA 11822

12/22/04 15:02 NA A B NA 4149825 NA 25072 NA 4114985 NA 24864 NA NA NA NA NA 11848

12/23/04 0:00 Holiday 12/24/04 0:00

Highlighted rows indicate vessel backwash.NA = data not available.

A-3
APPENDIX B 

ANALYTICAL DATA TABLES

 
B-1

Analytical Results from Long-Term Sampling, Rimrock, AZ

Sampling Date 6/30/04 7/07/04 7/14/04 

Sampling Location 

Parameter Unit 

IN AC TA TB IN AC TA TB IN AC TA TB 

Bed Volume 103 − − 0.9 0.9 − − 1.8 1.8 − − 2.7 2.7 Alkalinity mg/L(a) 355 − 367 351 330 − 382 365 383 − 371 367 3Fluoride mg/L 0.3 − 0.3 0.3 − − − − − − − − Sulfate mg/L 9.4 − 9.4 9.4 − − − − − − − − NO3-N mg/L 0.3 − 0.3 0.3 − − − − − − − − Orthophosphate mg/L(b) <0.1 − <0.1 <0.1 <0.1 − <0.1 <0.1 <0.1 − <0.1 <0.1 Silica (as SiO2) mg/L 26.0 − 25.4 23.9 25.7 − 24.4 24.1 24.0 − 24.3 23.9 Turbidity NTU 0.5 − 0.3 0.4 0.3 − 0.2 0.6 <0.1 − 0.2 0.9 pH − 7.0 7.4 7.0 7.0 7.0 7.2 7.0 7.0 7.0 7.2 7.1 7.1 Temperature oC 21.5 21.2 22.9 23.7 24.1 22.3 21.9 22.1 22.4 22.4 22.7 23.1 DO mg/L 3.8 4.9 3.6 3.8 4.1 5.0 4.1 3.7 3.5 4.7 3.7 3.6 ORP mV 475 637 637 649 476 596 596 611 488 607 619 628 5Free Chlorine mg/L − 0.4 0.4 0.4 − 0.4 0.4 0.4 − 0.4 0.4 0.4 Total Chlorine mg/L − 0.6 0.6 0.6 − 0.7 0.6 0.5 − 0.6 0.6 0.6 Total Hardness mg/L(a) 287.0 − 297.7 298.5 − − − − − − − − 

Ca Hardness mg/L(a) 171.3 − 174.8 174.3 − − − − − − − − Mg Hardness mg/L(a) 115.7 − 122.9 124.2 − − − − − − − − 

As (total) μg/L 59.2 − 1.0 0.3 78.5 − 1.2 0.3 79.2 − 0.8 0.3 As (total soluble) μg/L 59.1 − 0.9 0.3 − − − − − − − − As (particulate) μg/L 0.1 − 0.1 <0.1 − − − − − − − − As (III) μg/L 0.8 − 0.6 0.3 − − − − − − − − As (V) μg/L 58.3 − 0.3 <0.1 − − − − − − − − Total Fe μg/L <25 − <25 <25 <25 − <25 <25 <25 − <25 <25 <Dissolved Fe μg/L <25 − <25 <25 − − − − − − − − Total Mn μg/L 1.0 − 0.4 0.4 0.7 − <0.1 <0.1 0.4 − <0.1 <0.1 Dissolved Mn μg/L 1.1 − 0.7 0.6 − − − − − − − − 

(a) As CaCO3. (b) As PO4. 

IN = inlet; AC = after prechlorination (field parameters only); TA = after tank A; TB = after tank B. 
B-2

Analytical Results from Long-Term Sampling, Rimrock, AZ

Sampling Date 7/28/04 8/04/04 8/11/04 

Sampling Location 

Parameter Unit 

IN AC TA TB IN AC TA TB IN AC TA TB 

Bed Volume 103 − − 4.6 4.6 − − 5.6 5.6 − − 6.6 6.5 Alkalinity mg/L(a) 369 − 381 377 379 − 367 395 376 − 376 381 3Fluoride mg/L 0.3 − 0.3 0.3 − − − − − − − − Sulfate mg/L 10.0 − 10.0 10.0 − − − − − − − − NO3-N mg/L 0.2 − 0.2 0.2 − − − − − − − − Orthophosphate mg/L(b) <0.1 − <0.1 <0.1 <0.1 − <0.1 <0.1 <0.1 − <0.1 <0.1 Silica (as SiO2) mg/L 24.6 − 24.5 24.3 25.3 − 25.6 25.0 25.3 − 25.2 25.0 Turbidity NTU 0.2 − 0.3 0.2 0.3 − 0.3 0.5 0.1 − 0.2 0.1 pH − 7.0 7.2 7.1 7.1 7.0 7.0 7.0 7.0 7.0 7.2 7.1 7.0 Temperature oC 26.1 24.5 26.7 24.0 22.0 21.7 21.0 21.1 21.9 21.0 21.2 21.1 DO mg/L 4.4 5.5 4.2 4.1 4.2 4.1 4.0 3.8 4.2 5.8 4.1 4.1 ORP mV 484 590 599 613 203 609 634 647 247 587 627 641 2Free Chlorine mg/L − 0.5 0.5 0.4 − 0.5 0.4 0.4 − 0.4 0.4 0.4 Total Chlorine mg/L − 0.6 0.6 0.5 − 0.5 0.5 0.5 − 0.4 0.4 0.4 Total Hardness mg/L(a) 351.3 − 397.2 351.7 − − − − − − − − 

Ca Hardness mg/L(a) 208.0 − 236.1 207.0 − − − − − − − − Mg Hardness mg/L(a) 143.3 − 161.1 144.7 − − − − − − − − 

As (total) μg/L 56.0 − 1.0 0.3 81.4 − 1.4 0.3 57.0 − 0.7 0.3 As (total soluble) μg/L 57.6 − 1.0 0.3 − − − − − − − − As (particulate) μg/L <0.1 − <0.1 <0.1 − − − − − − − − As (III) μg/L 1.0 − 0.8 0.6 − − − − − − − − As (V) μg/L 56.6 − 0.2 <0.1 − − − − − − − − Total Fe μg/L <25 − <25 <25 <25 − <25 <25 <25 − <25 <25 <Dissolved Fe μg/L <25 − <25 <25 − − − − − − − − Total Mn μg/L 0.3 − <0.1 <0.1 0.5 − <0.1 <0.1 0.8 − 0.2 <0.1 Dissolved Mn μg/L 0.4 − <0.1 <0.1 − − − − − − − − 

(a) As CaCO3. (b) As PO4. 

IN = inlet; AC = after prechlorination (field parameters only); TA = after tank A; TB = after tank B. 
B-3

Analytical Results from Long-Term Sampling, Rimrock, AZ

Sampling Date 8/25/04 9/01/04 9/08/04 

Sampling Location 

Parameter Unit 

IN AC TA TB IN AC TA TB IN AC TA TB 

Bed Volume 103 − − 8.5 8.4 − − 9.4 9.4 − − 10.4 10.3 Alkalinity mg/L(a) 359 − 363 367 371 − 375 371 383 − 375 375 3

3

Fluoride mg/L 0.3 − 0.3 0.3 − − − − − − − − Sulfate mg/L 10.0 − 9.8 10.0 − − − − − − − − NO3-N mg/L 0.2 − 0.2 0.2 − − − − − − − − Orthophosphate mg/L(b) <0.1 − <0.1 <0.1 <0.1 − <0.1 <0.1 <0.1 − <0.1 <0.1 Silica (as SiO2) mg/L 26.7 − 27.2 26.9 25.3 − 25.2 25.1 25.6 − 25.2 25.6 Turbidity NTU 0.1 − 0.1 <0.1 0.1 − 0.3 0.2 0.1 − 0.1 0.2 pH − 7.0 7.0 7.0 6.9 7.1 7.6 7.1 7.1 6.9 7.1 6.9 6.9 Temperature oC 21.9 21.2 21.2 21.4 21.2 21.6 21.2 21.2 22.6 22.3 21.5 22.0 DO mg/L 3.3 4.7 3.6 3.4 4.6 4.5 4.4 4.6 3.5 3.4 3.6 3.5 ORP mV 210 610 649 658 213 608 637 637 431 642 668 685 2Free Chlorine mg/L − 0.5 0.3 0.3 − 0.4 0.3 0.3 − 0.4 0.4 0.4 Total Chlorine mg/L − 0.5 0.4 0.4 − 0.4 0.4 0.4 − 0.5 0.5 0.5 Total Hardness mg/L(a) 304.8 − 319.3 327.6 − − − − − − − − 

Ca Hardness mg/L(a) 183.0 − 182.3 182.3 − − − − − − − − Mg Hardness mg/L(a) 121.8 − 137.0 145.3 − − − − − − − − 

As (total) μg/L 64.6 − 2.7 1.0 77.5 − 1.1 0.4 78.5 − 1.1 0.4 As (total soluble) μg/L 61.1 − 2.8 1.2 − − − − − − − − As (particulate) μg/L 3.5 − <0.1 <0.1 − − − − − − − − As (III) μg/L 2.1 − 2.7 1.1 − − − − − − − − As (V) μg/L 59.0 − 0.1 0.1 − − − − − − − − Total Fe μg/L <25 − <25 <25 <25 − <25 <25 <25 − <25 <25 <

<

Dissolved Fe μg/L <25 − <25 <25 − − − − − − − − Total Mn μg/L 1.4 − 1.2 0.9 0.4 − <0.1 <0.1 0.3 − <0.1 0.1 Dissolved Mn μg/L 0.5 − 0.3 0.1 − − − − − − − − 

(a) As CaCO3. (b) As PO4. 

IN = inlet; AC = after prechlorination (field parameters only); TA = after tank A; TB = after tank B. 
B-4

Analytical Results from Long-Term Sampling, Rimrock, AZ 

Sampling Date 9/22/04 9/29/04 10/06/04 

Sampling Location 

Parameter Unit 

IN AC TA TB IN AC TA TB IN AC TA TB 

Bed Volume 103 − − 12.3 12.3 − − 13.4 13.3 − − 14.3 14.3 Alkalinity mg/L(a) 369 − 373 373 369 − 369 369 370 − 370 370 3Fluoride mg/L 0.4 − 0.5 0.3 − − − − − − − − Sulfate mg/L 8.9 − 8.8 8.7 − − − − − − − − NO3-N mg/L 0.2 − 0.2 0.2 − − − − − − − − Orthophosphate mg/L(b) <0.06 − <0.06 <0.06 <0.06 − <0.06 <0.06 <0.06 − <0.06 <0.06 Silica (as SiO2) mg/L 25.9 − 25.7 25.6 25.6 − 25.8 25.8 25.7 − 25.6 25.0 Turbidity NTU 0.1 − <0.1 0.1 <0.1 − <0.1 0.1 0.3 − 0.5 0.2 pH − 7.0 7.4 7.0 7.0 7.0 7.0 7.0 7.1 7.0 7.0 7.0 7.0 NTemperature oC 20.1 20.0 20.2 20.3 20.9 21.0 21.0 21.0 20.8 20.6 20.7 20.6 NDO mg/L 4.1 6.4 5.7 4.2 4.1 5.2 4.4 4.2 3.9 6.3 3.5 4.0 NORP mV 214 584 605 622 224 568 605 617 148 552 590 593 NFree Chlorine mg/L − 0.4 0.4 0.4 − 0.3 0.3 0.3 − 0.2 0.2 0.2 Total Chlorine mg/L − 0.5 0.4 0.4 − 0.4 0.4 0.4 − 0.2 0.2 0.2 Total Hardness mg/L(a) 331.8 − 339.7 331.8 − − − − − − − − 

Ca Hardness mg/L(a) 190.8 − 196.4 200.7 − − − − − − − − Mg Hardness mg/L(a) 141.0 − 143.3 131.1 − − − − − − − − 

As (total) μg/L 65.5 − 2.6 1.0 53.5 − 1.4 0.9 54.1 − 2.1 0.4 As (total soluble) μg/L 65.0 − 2.4 0.7 − − − − − − − − As (particulate) μg/L 0.5 − 0.2 0.3 − − − − − − − − As (III) μg/L 1.8 − 1.8 0.2 − − − − − − − − As (V) μg/L 63.2 − 0.6 0.5 − − − − − − − − Total Fe μg/L 127 − 27 56 <25 − <25 <25 <25 − <25 <25 <Dissolved Fe μg/L <25 − <25 <25 − − − − − − − − Total Mn μg/L 0.8 − 0.3 0.5 0.3 − 0.4 0.2 0.1 − 0.2 <0.1 Dissolved Mn μg/L 0.4 − 0.1 0.1 − − − − − − − − 

(a) As CaCO3. (b) As PO4. (c) Operator was not available to take water quality measurements. 

IN = inlet; AC = after prechlorination (field parameters only); TA = after tank A; TB = after tank B. NA = data not available. 
B-5

Analytical Results from Long-Term Sampling, Rimrock, AZ 

Sampling Date 10/20/04 10/27/04 11/03/04 

Sampling Location 

Parameter Unit 

IN AC TA TB IN AC TA TB IN AC TA TB 

Bed Volume 103 − − 16.2 16.1 − − 17.1 17.0 − − 18.1 18.0 Alkalinity mg/L(a) 377 − 377 373 386 − 382 390 369 − 377 369 3Fluoride mg/L 0.4 − 0.3 0.4 − − − − − − − − Sulfate mg/L 9.8 − 9.4 9.6 − − − − − − − − NO3-N mg/L 0.2 − 0.2 0.2 − − − − − − − − Orthophosphate mg/L(b) <0.06 − <0.06 <0.06 <0.06 − <0.06 <0.06 <0.06 − <0.06 <0.06 Silica (as SiO2) mg/L 24.9 − 25.0 24.6 25.2 − 25.5 25.3 24.7 − 25.0 25.0 Turbidity NTU 0.1 − 0.1 0.2 0.1 − 0.1 0.3 0.2 − 0.2 0.2 pH − 7.0 7.0 7.0 7.0 7.0 7.0 7.0 7.0 6.9 6.9 6.9 6.9 Temperature oC 20.1 20.1 20.3 20.3 19.5 19.8 19.7 19.7 20.4 20.6 20.6 20.6 2DO mg/L 4.0 4.5 4.1 4.1 4.2 3.6 3.7 3.6 4.0 3.8 4.1 3.9 ORP mV 190 637 681 710 216 552 577 590 180 491 565 591 5Free Chlorine mg/L − 0.2 0.2 0.2 − 0.3 0.3 0.3 − 0.3 0.3 0.3 Total Chlorine mg/L − 0.2 0.2 0.2 − 0.4 0.4 0.4 − 0.4 0.4 0.4 Total Hardness mg/L(a) 365.9 − 364.5 361.1 − − − − − − − − 

Ca Hardness mg/L(a) 214.4 − 214.3 212.1 − − − − − − − − Mg Hardness mg/L(a) 151.5 − 150.2 149.0 − − − − − − − − 

As (total) μg/L 50.8 − 1.3 1.0 56.5 − 1.6 0.8 56.3 − 1.6 0.8 As (total soluble) μg/L 50.2 − 1.1 0.7 − − − − − − − − As (particulate) μg/L 0.6 − 0.3 0.3 − − − − − − − − As (III) μg/L 2.2 − 1.3(c) 1.3(c) − − − − − − − − As (V) μg/L 48.0 − <0.1 <0.1 − − − − − − − − Total Fe μg/L <25 − <25 <25 <25 − 27.0 <25 <25 − 31.1 <25 <Dissolved Fe μg/L <25 − <25 <25 − − − − − − − − Total Mn μg/L 0.6 − <0.1 0.3 0.2 − 0.2 <0.1 0.3 − 0.4 0.2 Dissolved Mn μg/L 1.0 − <0.1 <0.1 − − − − − − − − 

(a) As CaCO3. (b) As PO4. (c) Data has been rerun. (d) Water quality measurement may have been taken from the wrong location. 

IN = inlet; AC = after prechlorination (field parameters only); TA = after tank A; TB = after tank B. 
Analytical Results from Long-Term Sampling, Rimrock, AZ 

Sampling Date 12/01/04 12/15/04(c) 

Sampling Location 

Parameter Unit 

IN AC TA TB IN AC TA TB 

Bed Volume 103 − − 22.1 21.9 − − 24.1 23.9 Alkalinity mg/L(a) 365 365 − 365 365 365 370 383 − 370 366 Fluoride mg/L − − − − 0.4 − 0.4 0.3 Sulfate mg/L − − − − 9.7 − 9.1 8.8 NO3-N mg/L − − − − 0.2 − 0.2 0.2 Orthophosphate mg/L(b) <0.06 <0.06 − <0.06 <0.06 <0.06 <0.06 <0.06 − <0.06 <0.06 Silica (as SiO2) mg/L 25.5 25.3 − 25.2 25.4 25.3 25.3 25.9 − 26.4 26.3 Turbidity NTU 0.1 0.1 − 0.1 0.2 0.1 0.3 0.2 − 0.2 0.1 pH − 7.0 6.9 6.9 6.9 6.9 6.9 6.9 6.9 Temperature oC 20.1 21.2 20.6 21.1 20.6 20.1 20.4 20.0 DO mg/L 4.3 3.4 3.9 3.5 4.0 3.2 3.5 3.4 ORP mV 267 626 646 673 230 618 660 672 Free Chlorine mg/L − 0.4 0.4 0.4 − 0.3 0.3 0.3 Total Chlorine mg/L − 0.5 0.5 0.5 − 0.4 0.3 0.3 Total Hardness mg/L(a) − − − − 383.7 − 374.2 376.7 

Ca Hardness mg/L(a) − − − − 241.0 − 233.8 235.2 Mg Hardness mg/L(a) − − − − 142.7 − 140.4 141.5 

As (total) μg/L 51.4 52.3 − 1.7 1.7 0.4 0.4 60.3 − 3.0 0.8 As (total soluble) μg/L − − − − 59.6 − 3.0 0.6 As (particulate) μg/L − − − − 0.7 − <0.1 0.2 As (III) μg/L − − − − 1.2 − 1.3 0.7 As (V) μg/L − − − − 58.4 − 1.7 <0.1 Total Fe μg/L <25 <25 − <25 <25 <25 <25 <25 − <25 <25 Dissolved Fe μg/L − − − − <25 − <25 <25 Total Mn μg/L 0.1 0.1 − <0.1 0.4 <0.1 <0.1 0.3 − <0.1 0.2 Dissolved Mn μg/L − − − − 0.1 − <0.1 <0.1 

B-6

(a) As CaCO3. (b) As PO4. (c) Water quality measurements were taken on 12/16/04. 

IN = inlet; AC = after prechlorination (field parameters only); TA = after tank A; TB = after tank B.