EPA/600/R-06/031 

April 2006 

Arsenic Removal from Drinking Water by Adsorptive Media 

U.S. EPA Demonstration Project at Bow, NH 

Six-Month Evaluation Report 

by 

Jeffrey L. Oxenham 

Abraham S.C. Chen 

Lili Wang 

Battelle 

Columbus, OH 43201-2693 

Contract No. 68-C-00-185 

Task Order No. 0019 

for 

Thomas J. Sorg 

Task Order Manager 

Water Supply and Water Resources Division 

National Risk Management Research Laboratory 

Cincinnati, Ohio 45268 

National Risk Management Research Laboratory 

Office of Research and Development 

U.S. Environmental Protection Agency 

Cincinnati, Ohio 45268 
DISCLAIMER 

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

(EPA) under Task Order 0019 of Contract 68-C-00-185 to Battelle. It has been subjected to the Agency’s 

peer and administrative reviews and has been approved for publication as an EPA document. Any 

opinions expressed in this paper are those of the author(s) and do not, necessarily, reflect the official 

positions and policies of the EPA. Any mention of products or trade names does not constitute 

recommendation for use by the EPA. 

ii 
FOREWORD 

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

community and to link researchers with their clients. 

Sally Gutierrez, Director 

National Risk Management Research Laboratory 

iii 
ABSTRACT

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

of the arsenic removal treatment technology demonstration project at the White Rock Water Company 

(WRWC) public water system, a small residential drinking water facility in Bow, NH. The objectives of 

the project are to evaluate the effectiveness of the ADI Group, Inc. (ADI) G2 media in removing arsenic 

to meet the new arsenic maximum contaminant level (MCL) of 10 μg/L, the reliability of the treatment 

system, the required system operation and maintenance (O&M) and operator’s skills, and the capital and 

O&M costs of the technology. The project also characterizes the water in the distribution system and 

process residuals produced by the treatment system. 

The arsenic adsorption system consisted of two vertical, 72-inch-diameter and 72-inch-sidewall-height 

stainless steel vessels configured in series. The adsorption vessels were originally designed to operate in 

parallel for the Holiday Acres Mobile Home Park in Allenstown, NH with a flowrate of 70 gallons per 

minute (gpm) (35 gpm per vessel). Due to the switch to the site in Bow with a total flowrate of about 40 

gpm, the flowrate was reduced by 43%; therefore, the system was reconfigured to operate in series. At 40 

gpm, each vessel provided an empty bed contact time (EBCT) of 16 min (or 32 min total contact time) 

and a hydraulic loading rate of 1.4-gpm/ft2

. The 16-min EBCT was 60% longer than that normally 

recommended by the vendor and the 1.4-gpm/ft2

 hydraulic loading rate was about 50% lower than that 

normally applied to the G2 media. 

The G2 media is a granular, calcined diatomite substrate coated with ferric hydroxide. Because of its 

inherently high pH values from the manufacturing process, the G2 media was conditioned on-site with 

sulfuric acid before the system was put into service. To increase the media adsorption capacity, the raw 

water was adjusted to a target value of 6.8, and later 6.4, using a 93% sulfuric acid solution. The treated 

water was adjusted for pH again to a target value of 7.5 using a 25% caustic solution before entering the 

distribution system. In-line pH probes were used to monitor the pH values of the feed water and treated 

water but the rates of acid and caustic addition were controlled via manual adjustments to the pump stroke 

length. The relative feed rates were then flow-paced with a water meter located on the discharge line 

following the treatment system. 

The arsenic adsorption system became operational on October 13, 2004. Through April 24, 2005, the 

system operated for 1,741 hr, treating approximately 3,858,000 gal of water or 6,067 bed volumes (BVs). 

Total As concentrations in the raw water averaged 49.3 μg/L, present almost entirely as As(V). After the 

lead vessel, greater than 30 μg/L of total As was unexpectedly detected in samples collected just after 

startup on October 13 and about one week later on October 19, 2004. After about 380 BVs of throughput, 

total As concentrations decreased to 12.6 to 15.6 μg/L before beginning a steady increase to 26.3 μg/L at 

about 2,600 BVs by April 12, 2005. Total As concentrations after the lag vessel also were high during 

the first two weeks of system operation, with 16.7 to 21.8 μg/L of arsenic measured on October 13 and 

October 19, 2004, respectively. Afterwards, the concentrations dropped to 1.7 μg/L after about 2,500 

BVs and then increased steadily to 5.8 μg/L after about 5,700 BVs by April 12, 2005. ADI attributed the 

elevated arsenic concentrations just after the system startup to the leaching of arsenic from the G2 media 

prepared with FeCl3 containing arsenic and manganese as impurities. While this might explain the 

elevated arsenic levels observed in the treated water during the first two weeks of system operation, it 

does not explain why the arsenic concentrations remained high (i.e., 12.6 μg/L or greater) following the 

lead vessel throughout the first six months of operation. 

Increases in both manganese and silica were observed in the treated water following the adsorption 

vessels, indicating leaching of these constituents from the media. After about 3,000 BVs, manganese 

concentrations decreased to levels similar to those in the raw water. The leaching of silica from both 

iv 
vessels leveled off after about 2,000 BVs, but continued throughout the remainder of the study period 

with an increase in concentrations ranging from 1.6 to 6.2 mg/L. 

The system was backwashed only twice during this period because of low pressure losses (i.e., 1-2 

pounds per square inch [psi]) across the adsorption vessels. Analysis of the backwash water indicated 

that soluble As concentrations were either similar to or lower than the levels measured in the source 

water. Since finished water was used for backwash, some arsenic might have been desorbed from the 

media during backwashing. Future backwash samples will include collection and analysis of total 

suspended solids (TSS) and total As, Fe, and Mn. 

Comparison of the distribution system sampling results before and after the installation of the ADI G2 

media system showed a decrease in arsenic concentration (from 36.9 - 52.3 μg/L to 3.9 - 12.4 μg/L) at all 

three EPA Lead and Copper Rule (LCR) sampling locations. Manganese concentrations increased to as 

high as 16.0 μg/L in the distribution system during the first three months of system operation, apparently 

due to leaching of manganese from the G2 media, as mentioned above. Following a drop in pH of the 

treated water in December 2004, the lead concentration in the January 12, 2005 sample increased to 9.9 

μg/L at one sampling location and copper levels increased across all three sampling locations, with the 

most noticeable increase exceeding the action level of 1.3 mg/L at one location. During the subsequent 

monthly sampling events, the pH values were better controlled; however, the lead and copper levels 

continued to be higher than those observed before the pH drop in January. 

The most significant operational issue observed was related to the addition of acid and caustic necessary 

to maintain the desired pH ranges of the feed water to the treatment system and the finish water to the 

storage tank and distribution system. Confounding the proper addition of acid and caustic were 

continuing discrepancies observed in pH readings from the inline pH probes versus a WTW field meter 

used to measure pH at sampling locations across the treatment train. In fact, an inadvertent lowering of 

the caustic addition in late December resulted in the pH drop observed in the distribution system samples 

collected on January 12, 2005, and the corresponding increase in lead and copper levels in the distribution 

system as described above. 

The capital investment cost of $154,700 includes $102,600 for equipment, $12,500 for site engineering, 

and $39,600 for installation. Using the system’s actual capacity of 40 gpm (57,600 gal per day [gpd]), the 

capital cost was $3,868/gpm ($2.68/gpd) and equipment-only cost was $2,565/gpm ($1.78/gpd). These 

calculations did not include the cost of the building construction. 

O&M costs included only incremental costs associated with the adsorption system, such as media 

replacement and disposal, chemical supply, electricity, and labor. Incremental costs for electricity were 

negligible. Although media replacement and disposal did not take place during the first six months of 

operation, the cost to change out the lead vessel was estimated to be $9,396 based on information 

provided by the vendor and a local subcontractor. This cost was used to estimate the media replacement 

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

breakthrough. 

v 
CONTENTS

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

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

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

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

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

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

ABBREVIATIONS AND ACRONYMS ..................................................................................................viii 

ACKNOWLEDGMENTS ............................................................................................................................x 

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...........................................................................................................5 

3.1 General Project Approach.............................................................................................................5 

3.2 System O&M and Cost Data Collection .......................................................................................6

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

3.3.1 Source Water Sample Collection. .....................................................................................8 

3.3.2 Treatment Plant Water Sample Collection........................................................................8 

3.3.3 Backwash Water Sample Collection .................................................................................8 

3.3.4 Backwash Solid Sample Collection ..................................................................................8 

3.3.5 Distribution System Water Sample Collection .................................................................8 

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

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

3.4.2 Preparation of Sampling Coolers ......................................................................................9 

3.4.3 Sample Shipping and Handling.........................................................................................9 

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

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

4.1 Facility Description.....................................................................................................................11 

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

4.1.2 Pre-Demonstration Treated Water Quality......................................................................14 

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

4.2 Treatment Process Description ...................................................................................................14 

4.3 System Installation......................................................................................................................20 

4.3.1 Permitting........................................................................................................................20 

4.3.2 Building Construction .....................................................................................................20 

4.3.3 Installation, Shakedown, and Startup..............................................................................21 

4.4 System Operation........................................................................................................................21 

4.4.1 Operational Parameters...................................................................................................21 

4.4.2 Backwash ........................................................................................................................22 

4.4.3 Residuals Management ...................................................................................................22

4.4.4 System Operation Reliability and Simplicity..................................................................22 

4.5 System Performance ...................................................................................................................24 

4.5.1 Treatment Plant Sampling...............................................................................................24

4.5.2 Backwash Water Sampling .............................................................................................33 

vi 
4.5.3 Distribution System Water Sampling..............................................................................33 

4.6 System Costs...............................................................................................................................34 

4.6.1 Capital Costs ...................................................................................................................34 

4.6.2 Operation and Maintenance Costs...................................................................................36 

5.0 REFERENCES ....................................................................................................................................39 

APPENDICES 

APPENDIX A: Operational Data..........................................................................................................A-1 

APPENDIX B: Analytical Results........................................................................................................ B-1 

FIGURES 

Figure 4-1. Existing Underground Treatment and Control Structure ..................................................... 11 

Figure 4-2. Existing Storage Tanks in Underground Concrete Structure ............................................... 12 

Figure 4-3. Existing Activated Alumina System in the Underground Treatment and Control 

Structure ............................................................................................................................... 12 

Figure 4-4. Schematic of G2 Media Adsorption System (Provided by ADI)......................................... 16 

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

Figure 4-6. ADI G2 Media Arsenic Adsorption System ........................................................................ 19 

Figure 4-7. New Treatment Building Addition....................................................................................... 20 

Figure 4-8. Concentration of Arsenic Species at the IN, AP, TA, and TB Sampling Locations............ 28 

Figure 4-9. Total Arsenic Breakthrough Curves..................................................................................... 29 

Figure 4-10. Total Manganese Concentrations Over Time....................................................................... 30 

Figure 4-12. Silica Concentrations Over Time ......................................................................................... 32 

Figure 4-13. Media Replacement and O&M Costs .................................................................................. 38 

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.................................................. 5 

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

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

Table 4-1. Raw and Treated Water Quality Data .................................................................................. 13 

Table 4-2. Physical and Chemical Properties of G2 Media................................................................... 15 

Table 4-3. Design Specifications of the G2 Media System................................................................... 17 

Table 4-4. Summary of G2 Media Treatment System Operation.......................................................... 22 

Table 4-5. Summary of Arsenic, Iron, and Manganese Analytical Results........................................... 25 

Table 4-6. Summary of Water Quality Parameter Measurements......................................................... 26 

Table 4-7. Calculation of Acid Consumption for pH Adjustment at the WRWC Site.......................... 32 

Table 4-8. Backwash Water Sampling Results ..................................................................................... 33 

Table 4-9. Distribution System Sampling Results................................................................................. 35 

Table 4-10. Capital Investment for the G2 Media Treatment System..................................................... 36 

Table 4-11. O&M Costs for the G2 Media Treatment System................................................................ 37 

vii 
ABBREVIATIONS AND ACRONYMS 

∆p differential pressure 

AA activated alumina 

AAL American Analytical Laboratories 

ADI ADI Group, Inc. 

Al aluminum 

AM adsorptive media 

As arsenic 

bgs below ground surface 

BV bed volume(s) 

C/F coagulation/filtration 

Ca calcium 

Cl2 chlorine 

CRF capital recovery factor 

Cu copper 

DO dissolved oxygen 

EBCT empty bed contact time 

EPA U.S. Environmental Protection Agency 

F fluoride 

Fe iron 

gal gallons 

GFH granular ferric hydroxide 

GFO granular ferric oxide 

gpd gallons per day 

gpm gallons per minute 

HDPE high-density polyethylene 

HAMHP Holiday Acres Mobile Home Park 

hr hours 

ICP-MS inductively coupled plasma-mass spectrometry 

ID identification 

IX ion exchange 

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 

μg/L micrograms per liter 

min minutes 

viii 
ABBREVIATIONS AND ACRONYMS (CONTINUED) 

Mn manganese 

Mo molybdenum 

mV millivolts 

N/A not applicable 

Na sodium 

NA not available 

NaOCl sodium hypochlorite 

NHDES New Hampshire Department of Environmental Services 

NRMRL National Risk Management Research Laboratory 

NSF NSF International 

NTU nephlemetric turbidity unit 

O&M operation and maintenance 

ORD Office of Research and Development 

ORP oxidation-reduction potential 

Pb lead 

psi pounds per square inch 

PO4 orthophosphate 

PVC polyvinyl chloride 

QA quality assurance 

QA/QC quality assurance/quality control 

QAPP Quality Assurance Project Plan 

RPD relative percent difference 

Sb antimony 

SDWA Safe Drinking Water Act 

SiO2 silica 

SM system modification 

SO4 sulfate 

STMGID South Truckee Meadows General Improvement District 

STS Severn Trent Services 

TBD to be determined 

TCLP Toxicity Characteristic Leaching Procedure 

TDS total dissolved solids 

TOC total organic carbon 

TSS total suspended solids 

V vanadium 

VOC volatile organic compound 

WRWC White Rock Water Company 

ix 
ACKNOWLEDGMENTS

The authors wish to extend their sincere appreciation to the staff of C&C Water Services of Gilford and 

Bow in New Hampshire. The C&C Water Services staff monitored the treatment system daily, 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 efforts. 

x 
1.0 INTRODUCTION 

1.1 Background 

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

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

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

established a maximum contaminant level (MCL) for arsenic 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. Holiday Acres Mobile Home Park (HAMHP) in Allenstown, NH, was originally 

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. The ADI G2 adsorptive media was 

selected for the Allenstown site. In January 2004, HAMHP decided to withdraw from the demonstration 

study due to the facility’s decision to switch to an alternate public water supply source. 

In March 2004, EPA decided to replace HAMHP with the White Rock Water Company (WRWC) public 

water system, operated by C&C Water Services, serving the community of Village Shore Estates at Bow, 

NH. Because the design flowrate for the WRWC system was about half of the flowrate at HAMHP, the 

ADI adsorption system was re-configured to operate in series, increasing the empty bed contact time 

(EBCT) from 18 to 32 min total (i.e., 16 min per vessel, two vessels in series). 

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 reported in an EPA 

report (Wang et al., 2004) posted on an EPA Web site (http://www.eap.gov/ORD/NRMRL/arsenic/ 

resource.htm). 

1
1.3 

Table 1-1. Summary of Arsenic Removal Demonstration 

Technologies and Source Water Quality Parameters 

Demonstration Site 

Technology 

(Media) Vendor 

Design 

Flowrate 

(gpm) 

Source Water Quality 

As 

(μg/L) 

Fe 

(μg/L) pH 

WRWC (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(d) 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; WRWC = White Rock Water Company 

(a) System reconfigured from parallel to series operation due to lower flowrate of 40 gpm at the WRWC site 

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

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

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

Project Objectives 

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

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

objectives are to: 

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

systems. 

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

and operator’s skill levels. 

• Determine the capital and O&M costs of the technologies. 

• Characterize process residuals produced by the technologies. 

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

October 13, 2004 through April 24, 2005. The types of data collected include 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 

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

conclusions were made relating to the overall objectives of the treatment technology demonstration study. 

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

• Higher than 10 μg/L of arsenic breakthrough was observed after the lead vessel 

throughout this study period. The arsenic concentration increased to 26.3 μg/L 

after about 5,700 BVs of throughput. Elevated arsenic concentrations also were 

measured after the lag vessel immediately after the system startup. The 

concentration decreased to 1.7 μg/L and then increased to 5.8 μg/L at 5,700 BVs 

of throughput. Lowering the pH values to as low as 6.1 did not appear to 

improve the media performance. 

• Increases in manganese and silica concentrations to as high as 35.8 μg/L and 61.8 

mg/L, respectively, were observed in the treated water following the G2 media 

treatment, indicating leaching of these constituents from the media. According to 

the vendor, some arsenic and manganese existed as impurities in the FeCl3 

solution used to produce the G2 media; silica was the base substrate of the G2 

media. The concentrations of both manganese and silica leveled off after 2,000 

to 3,000 BVs of throughput. 

• Other than a few exceptions, arsenic, iron, and manganese concentrations in the 

distribution system closely mirrored those measured after the treatment system. 

A loss of pH control resulted in lower than normal pH values in the distrubution 

system, causing a significant increase in the lead and copper levels with the 

copper concentration at one location exceeding its action level of 1.3 mg/L. 

• Total and free chlorine residuals measured before and after the adsorption vessels 

were similar, indicating little or no chlorine consumption by the G2 media. 

Required system O&M and operator’s skill levels: 

• Generally, the operation of the treatment system did not require additional skills 

beyond those necessary to operate the original treatment equipment used at the 

site prior to the demonstration. The daily demand on the system operator was 

typically about 20 min to inspect the system and record operational parameters. 

Based on the size of the population served and the treatment technology, the 

State of New Hampshire requires Level 1A Certification for operation of the 

treatment system and is considering upgrading this requirement to Level 1 

certification. 

• A significant O&M issue for this system was the need for acid and caustic 

addition to maintain the desired pH ranges of the feed water to the treatment 

system and the finished water to the distribution system. 

Process residuals produced by the technology: 

• Residuals produced by the operation of the treatment system included backwash 

water and spent media. Because the media was not replaced during the first six 

months of system operation, the only residual produced was backwash water. 

3
• Because the pressure drop across the vessels was low (i.e., 1-2 psi), the system 

was backwashed only twice during the first six months of operation. Each 

backwash event produced approximately 2,000 gal of wastewater per vessel. 

Soluble arsenic concentrations in the backwash water from the lead vessel ranged 

from 40.3 to 42.8 μg/L. Soluble arsenic concentrations in the backwash water 

from the lag vessel ranged from 11.4 to 26.1 μg/L. 

Cost-effectiveness of the technology: 

• Using the system’s actual capacity of 40 gallons per minute (gpm) (57,600 

gallons per day [gpd]), the capital cost was $3,868/gpm ($2.68/gpd) and 

equipment-only cost was $2,565/gpm ($1.78/gpd). These calculations did not 

include the cost of the building construction. 

• Although media replacement and disposal did not take place during the first six 

months of operation, the cost to change out the lead vessel was estimated to be 

$9,396 based on information provided by the vendor and a local subcontractor. 

4
3.1 

3.0 MATERIALS AND METHODS

General Project Approach 

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

the ADI adsorption system began on October 13, 2004. Table 3-2 summarizes the types of data collected 

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

was determined based on its ability to consistently remove arsenic to the target MCL of 10 μg/L; this was 

monitored through the collection of biweekly and monthly 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. 

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

Activity Date 

Introductory Meeting Held April 22, 2004 

Revised Vendor Quotation Submitted to Battelle May 10, 2004 

Purchase Order Modification Completed June 10, 2004 

Engineering Package Submitted to NHDES June 14, 2004 

Steel Floor for Treatment System Installed June 25, 2004 

Adsorption Vessels Delivered to Site June 28, 2004 

Permit Issued by NHDES August 23, 2004 

Draft Study Plan Issued September 2, 2004 

System Installation Completed September 13, 2004 

Final Study Plan Issued October 6, 2004 

Media Conditioning and System Shakedown Completed October 11, 2004 

Performance Evaluation Begun October 13, 2004 

NHDES = New Hampshire Department of Environmental Services. 

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 preventive 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 

5
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 on the system operation were recorded on an Operator Labor Hour Log Sheet. 

The cost-effectiveness of the system is evaluated based on the cost per 1,000 gal ($/1,000 gal) of water 

treated. This requires 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 reported in an EPA report (Chen et al., 2004) posted on an 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 cycle and the need to replace the media upon arsenic breakthrough. 

Backwash water was sampled and analyzed for chemical characteristics. 

3.2 System O&M and Cost Data Collection 

The plant operator performed daily, weekly, and monthly system O&M and data collection following the 

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

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

Sheet; checked the sodium hypochlorite, acid, and caustic drum levels; and conducted visual inspections 

to ensure normal system operations. In the event of problems, the plant operator would contact the 

Battelle Study Lead, who then would determine if ADI should be contacted for troubleshooting. The 

plant operator recorded all relevant information on the Repair and Maintenance Log Sheet. Once a week 

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 OnSite Water Quality Parameters Log Sheet. 

Capital costs for the ADI system consisted of costs for equipment, site engineering, and system 

installation. The O&M costs consisted primarily of costs for the media replacement and spent media 

disposal, chemical and electricity consumption, and labor. Chemical usage, including sodium 

hypochlorite, acid, and caustic, and electricity consumption were tracked using the System Operation Log 

Sheet. 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 completing the daily field logs; replenishing the sodium 

hypochlorite, acid, and caustic solutions; ordering supplies; performing system inspections; and other 

items as recommended by the equipment vendor. The demonstration-related work included activities 

such as performing field measurements, collecting and shipping samples, and communicating with the 

Battelle Study Lead. The demonstration-related activities were recorded but not included in the cost 

analysis. 

3.3 Sample Collection Procedures and Schedules 

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

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

analytes measured during each sampling event. Specific sampling requirements for analytical methods, 

sample volumes, containers, preservation, and holding times are presented in Table 4-1 of the EPAendorsed Quality Assurance Project Plan (QAPP) (Battelle, 2003). 

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 

Storage Tanks 1 Once 

during the 

initial site 

visit 

As(total), particulate and 

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

Fe (total and soluble), Mn 

(total and soluble), Al (total 

and soluble), Na, Ca, Mg, 

V, Mo, Sb, Cl, F, SO4, 

SiO2, PO4, TOC, alkalinity, 

and pH. 

04/22/04 

Treatment 

Plant Water 

After wells combined 

(IN), 

after chlorination and 

pH adjustment (AP) , 

after Vessel A (TA), 

and after Vessel B 

(TB) 

4 Biweekly On-site: pH, temperature, 

DO/ORP, Cl2 (free and 

total) (except IN location). 

Off-site: As (total), Fe 

(total), Mn (total), SiO2, 

PO4, turbidity, and 

alkalinity. 

10/19/04, 10/26/04, 

11/02/04, 11/16/04, 

11/30/04, 01/04/05, 

01/18/05, 02/15/05, 

03/01/05, 03/15/05, 

04/12/05 

Bimonthly On-site: pH, temperature, 

DO/ORP, and Cl2 (free and 

total) (except IN location). 

Off-site: As(total), 

particulate and soluble As, 

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

soluble), Mn (total and 

soluble), Ca, Mg, F, NO3, 

SO4, SiO2, PO4, turbidity, 

and alkalinity. 

10/13/04, 12/14/04, 

02/01/05, 03/29/05 

Distribution 

Water 

Three residences 

previously used as 

LCR sampling 

locations 

3 Monthly pH, alkalinity, As, Fe, Mn, 

Pb, and Cu. 

Baseline 

sampling(b): 

07/21/04, 08/05/04, 

08/18/04, 09/08/04 

Monthly sampling: 

11/03/04, 12/08/04, 

01/12/05, 02/09/05, 

03/09/05, 04/20/05 

Backwash 

Water 

Sample ports on 

backwash discharge 

line from each vessel 

2 During 

each 

backwash 

event 

TDS, turbidity, pH, As 

(soluble), Fe (soluble), and 

Mn (soluble) 

01/11/05 

04/12/05 

Residual 

Sludge 

Backwash discharge 

area 

2-3 TBD TCLP Metals TBD 

(a) The abbreviation in each parenthesis corresponds to the sample location in Figure 4-5. 

(b) Four baseline sampling events were performed before the system became operational. 

TBD = to be determined. 

7 
3.3.1 Source Water Sample Collection. During the initial visit to the WRWC site, Battelle 

collected one set of source water samples for detailed water quality analyses. The source water also was 

speciated for particulate and soluble As, iron (Fe), manganese (Mn), aluminum (Al), and As(III) and 

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

agitation, which might cause unwanted oxidation. Arsenic speciation kits and containers for water quality 

samples were prepared as described in Section 3.4. 

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

study, water samples were collected across the treatment train by the plant operator. Samples were 

collected biweekly on an eight-week cycle. For the first three biweekly events, treatment plant samples 

were collected at four locations (i.e., after wells combined [IN], after chlorination and pH adjustment 

[AP], after Vessel A [TA], and after Vessel B [TB]), and analyzed for the analytes listed under the 

biweekly treatment plant analyte list (see Table 3-3). Bimonthly (once every eight weeks) treatment 

plant samples collected at the same four locations were speciated for arsenic and analyzed for the analytes 

listed in Table 3-3 under “bimonthly.” The sampling frequency was reduced from weekly as stated in the 

Study Plan to biweekly following the first month of system operations. 

3.3.3 Backwash Water Sample Collection. Two backwash water samples were collected on 

January 11 and April 12, 2005 from the sample taps located at the backwash water effluent line from each 

vessel. Unfiltered samples were measured on site for pH using a field pH meter, and a 1-gallon sample 

was sent to American Analytical Laboratories (AAL) for total dissolved solids (TDS) and turbidity 

measurements. Filtered samples using 0.45-μm filters were sent to Battelle’s inductively coupled plasmamass spectrometry (ICP-MS) laboratory for soluble As, Fe, and Mn analyses. Arsenic speciation was not 

performed for the backwash water samples. 

3.3.4 Backwash Solid Sample Collection. Backwash solid samples were not collected in the 

initial six months of this demonstration. Solid/sludge samples will be collected from the backwash 

discharge during the second half of the demonstration. The solid/sludge samples will be collected in glass 

jars and submitted to TCCI Laboratories for Toxicity Characteristic Leaching Procedure (TCLP) tests. 

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 arsenic, lead, and copper levels. During July through September 2004, 

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

conducted at 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 three locations. 

The three homes selected for the sampling had been included in the Lead and Copper Rule (LCR) 

sampling in the past. The samples were collected following an instruction sheet developed according to 

the Lead and Copper Rule Reporting Guidance for Public Water Systems (EPA, 2002). First-draw 

samples were collected from cold-water faucets that had not been used for at least six hours to ensure that 

stagnant water was sampled. The sampler recorded the date and time of last water use before sampling 

and the date and time of sample collection for calculation of the stagnation time. Analytes for the 

baseline samples coincided with the monthly distribution system water samples as described in Table 3-3. 

Arsenic speciation was not performed for the distribution water samples. 

3.4 Sampling Logistics 

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

sample shipping and handling are discussed as follows: 

8
3.4.1 Preparation of Arsenic Speciation Kits. The arsenic field speciation method used an anion 

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

Arsenic speciation kits 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. All sample bottles were new and contained appropriate 

preservatives. Each sample bottle was taped with a pre-printed, colored-coded, and waterproof label. 

The sample label consisted of sample identification (ID), date and time of sample collection, sampler 

initials, location, sent to, 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 for the specific analysis to be performed. The sampling locations were color-coded for 

easy identification. For example, red, orange, yellow, and green were used to designate sampling 

locations for IN, AP, TA, and TB, respectively. Pre-labeled bottles were placed in one of the plastic bags 

(each corresponding to a specific sampling location) in a sample cooler. When arsenic speciation samples 

were to be collected, an appropriate number of arsenic speciation kits also were included in the cooler. 

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

sampling locations and/or the two backwash sampling locations (one for each vessel). 

In addition, a packet containing all sampling and shipping-related supplies, such as latex gloves, sampling 

instructions, chain-of-custody forms, prepaid Federal Express air bills, ice packs, and bubble wrap, also 

was placed in the cooler. Except for the operator’s signature, the chain-of-custody forms and prepaid 

Federal Express air bills had already been completed with the required information. The sample coolers 

were shipped via Federal Express to the facility approximately one week prior to the scheduled sampling 

date. 

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

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

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

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

logged into the laboratory sample receipt log. Discrepancies, if noted, were addressed by the field sample 

custodian, and the Battelle Study Lead was notified. 

Samples for water quality analyses by Battelle’s subcontract laboratories were packed in coolers at 

Battelle and picked up by a courier from either AAL (Columbus, OH) or TCCI Laboratories (New 

Lexington, OH). The samples for arsenic speciation analyses were stored at Battelle’s ICP-MS 

Laboratory. The chain-of-custody forms remained with the samples from the time of preparation through 

analysis and final disposition. All samples were archived by the appropriate laboratories for the 

respective duration of the required hold time, and disposed of properly thereafter. 

3.5 Analytical Procedures 

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

2003). Field measurements of pH, temperature, and DO/ORP were conducted by the plant operator using 

a WTW Multi 340i handheld meter, which was calibrated prior to use following the procedures provided 

in the user’s manual. The plant operator collected a water sample in a 400-mL plastic beaker and placed 

the Multi 340i probe in the beaker until a stable, measured value was reached. The plant operator also 

performed free and total chlorine measurements using Hach chlorine test kits. 

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%, 

9
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 the Round 1 arsenic 

study. 

10
4.1 

4.0 RESULTS AND DISCUSSION 

Facility Description 

The WRWC public water system is operated by C&C Water Services and supplies water to 96 homes in 

the community of Village Shore Estates at Bow, NH. The facility is located on a wooded lot at 6 Rocky 

Point Drive, Bow, NH. Figure 4-1 shows the small underground structure that housed the existing water 

system components prior to installation of the ADI adsorption system. The water source is groundwater 

from three on-site bedrock wells (Wells 1, 2, and 3). The total flowrate from the three wells is 

approximately 40 gpm at startup, based on the information provided by the plant operator. The well 

pumps are activated based on the water level in two 15,000-gallon storage tanks (Figure 4-2) housed in a 

separate underground structure located about 50 ft from the treatment and control structure. Prior to the 

beginning of the demonstration study, the system was estimated to run approximately 6 to 8 hr per day 

with an average daily use rate of 15,000 to 20,000 gpd. The existing treatment process included the 

addition of a dilute sodium hypochlorite solution for disinfection and a caustic solution to raise pH to 

make the treated water less corrosive in the distribution system. Approximately 10-15% of the total flow 

also was treated with a small activated alumina (AA) system, shown in Figure 4-3, which had been at the 

site for many years. The AA system was removed from the site prior to installation of the ADI adsorption 

system. 

Figure 4-1. Existing Underground Treatment and Control Structure 

4.1.1 Source Water Quality. Source water samples were collected on April 22, 2004, and 

subsequently analyzed for the analytes shown in Table 3-3. The results of the source water analyses, 

along with those provided by the facility to EPA for the demonstration site selection and those obtained 

from the New Hampshire Department of Environmental Services (NHDES) are presented in Table 4-1. 

11
Figure 4-2. Existing Storage Tanks in Underground Concrete Structure 

Figure 4-3. Existing Activated Alumina System in the 

Underground Treatment and Control Structure 

12
Table 4-1. Raw and Treated Water Quality Data 

Parameter Units 

U.S. EPA 

Raw 

Water 

Data(a) 

Battelle 

Raw 

Water 

Data 

NHDES Raw 

Water Data(b) 

NHDES 

Treated 

Water Data(c) 

Sampling Date 06/10/98 04/22/04 06/02 

12/29/99­

04/26/04 

pH – 7.7 6.8 N/A 7.6-7.8 

Total Alkalinity mg/L 56.0 54.0 N/A N/A 

Hardness (as 

CaCO3) mg/L 83.0 92.7 N/A N/A 

Turbidity mg/L 0.4 N/A N/A N/A 

Chloride mg/L N/A 41.0 N/A 34-35 

Fluoride mg/L 0.8 0.6 N/A 0.9-1.0 

Sulfide mg/L N/A N/A N/A N/A 

Sulfate mg/L 15.5 12.0 N/A 11-12 

Nitrate-Nitrite mg/L 0.3 N/A N/A N/A 

Silica (as SiO2) mg/L N/A 19.7 N/A N/A 

Orthophosphate mg/L N/A <0.10 0.019-0.076 N/A 

TOC mg/L 1.0 <0.7 <0.5 N/A 

As(total) μg/L 44.2 39.2 32-47 36.3-47 

As (total soluble) μg/L 44.9 44.1 N/A N/A 

As (particulate) μg/L N/A <0.1 N/A N/A 

As(III) μg/L 0.5 0.5 N/A N/A 

As(V) μg/L 44.4 43.6 N/A N/A 

Total Fe μg/L 60.0 <25 N/A <50 

Soluble Fe μg/L N/A <25 N/A N/A 

Total Al μg/L <400 <10 N/A N/A 

Soluble Al μg/L N/A <10 N/A N/A 

Total Mn μg/L 25.0 2.1 N/A <5 

Soluble Mn μg/L N/A 1.5 N/A N/A 

Total V μg/L N/A 0.6 N/A N/A 

Soluble V μg/L N/A 0.6 N/A N/A 

Total Mo μg/L N/A 1.9 N/A N/A 

Soluble Mo μg/L N/A 3.0 N/A N/A 

Total Sb μg/L N/A 0.2 N/A <3 

Soluble Sb μg/L N/A 0.7 N/A N/A 

Total Na mg/L N/A 17.0 N/A 16.6-17.5 

Total Ca mg/L 24.7 28.3 18.2-39.7 N/A 

Total Mg mg/L 5.2 5.3 3.5-7.1 N/A 

(a) Results of source water sample collected in 1998. 

(b) Raw water samples from Wells 1, 2, and 3 separately. 

(c) Treated water samples are blended water from Wells 1, 2, and 3.

N/A = not analyzed. 

Total arsenic concentrations of the source water ranged from 32 to 47 μg/L. Based on the April 22, 2004 

sampling results, the majority of arsenic present was in the As(V) form, with only a small amount (0.5 

μg/L) present as As(III). 

13
The pH values of the raw water ranged between 6.8 and 7.7, higher than the desired range of 6.0 to 7.0 

indicated by ADI for using the G2 media. 

The concentrations of iron (<25 to 60 μg/L) and other ions in the raw water were sufficiently low that 

pretreatment prior to the adsorption process was not required. The concentrations of orthophosphate and 

silica also were sufficiently low (i.e., <0.1 mg/L and 19.7 mg/L, respectively) and, therefore, were not 

expected to affect the As adsorption on the G2 media. 

4.1.2 Pre-Demonstration Treated Water Quality. Table 4-1 presents historic data for several 

analytes from treated water samples collected in compliance with the state monitoring and reporting 

requirements. Because the treatment process prior to distribution included only chlorination and caustic 

addition, concentrations of analytes in the treated water were very similar to those of the raw water. Total 

arsenic concentrations in the treated water ranged from 36.3 to 47 μg/L. Iron and manganese 

concentrations were below the respective detection limits of 50 and 5 μg/L. The pH values of the treated 

water ranged from 7.6 to 7.8. 

4.1.3 Distribution System. The distribution system serving the community of Village Shore 

Estates consists of a looped distribution line constructed primarily of polyvinyl chloride (PVC) pipe. The 

connections to the distribution system and piping within the residences themselves are primarily PVC and 

some copper pipe. It is believed that a few homes may have pipe with lead solder, and that no homes 

have lead pipe. 

Compliance samples from the distribution system are collected monthly for bacterial analysis and yearly 

for volatile organic compounds (VOCs). Under the EPA LCR, samples are collected from customer taps 

at five residences every three years. 

4.2 Treatment Process Description 

The ADI adsorption system uses G2 media for arsenic removal. The media consists of a granular, 

calcined diatomite substrate coated with ferric hydroxide. Table 4-2 presents physical and chemical 

properties of the media. The G2 media has NSF International (NSF) Standard 61 listing for use in 

drinking water applications. 

The ADI system is a fixed-bed downflow adsorption system. When the media reaches its capacity, the 

spent media may be removed and disposed of after being subjected to the EPA TCLP test. The media 

also can be regenerated using a 1% sodium hydroxide solution. However, due to the relatively small size 

of the treatment facility, spent media will be removed and disposed of to simplify system operations. 

The adsorption system at the WRWC site consists of two vertical, 72-inch-diameter and 72-inch-sidewallheight cylindrical filter vessels, configured in series. The adsorption vessels were originally designed to 

operate in parallel for HAMHP with a flowrate of 70 gpm (35 gpm per vessel). Due to the switch to the 

site in Bow with a total flowrate of about 40 gpm, the flowrate was reduced by 43%; therefore, the system 

was reconfigured to operate in series. As such, each vessel would provide for an EBCT of 16 min, 

compared to the 18 min per vessel EBCT the system would have provided as originally designed for the 

HAMHP site. Note that both of these EBCTs are much longer than the 10-min EBCT normally 

recommended by the vendor. Additionally, the hydraulic loading rate of the system was increased 

slightly from 1.2 to 1.4 gpm/ft2

 with the switch from the HAMHP to the WRWC site. Both of these 

loading rates are significantly lower than the 2.5 to 3.0 gpm/ft2

 that would normally be applied to the G2 

media. ADI recommended the use of 72-inch-diameter vessels with the intent of extending the media run 

length for the HAMHP site. Figure 4-4 is a process flow diagram of the adsorption system supplied by 

14
Table 4-2. Physical and Chemical Properties of G2 Media 

Physical Properties 

Parameter Value 

Matrix Diatomite impregnated with ferric 

hydroxide 

Physical Form Dry granules 

Color Dark brown 

Bulk Density (lb/ft3

) 47 

Specific Gravity (dry) 0.75 

Hardness (lb/in2

) 210 

Effective Size (mm) 0.32 

Uniformity Coefficient 1.8-2.0 

Bulk Relative Density 1.073 

Adsorption (%) 51.1 

Chemical Analysis 

Constituents Weight % 

Fe 5 – 6 

Na 9 – 10 

Al 0.5 

Diatomaceous Earth (a silica based material) Balance 

Trace Elements < 0.1 

Source: ADI 

ADI. The design features of the treatment system are summarized in Table 4-3, and a flow diagram along 

with the sampling/analysis schedule are presented in Figure 4-5. Key process components include: 

• Intake. Raw water was pumped from the three on-site bedrock wells (Wells 1, 2, 

and 3) and fed to the G2 media treatment system. The entry piping consisted of 2­

inch PVC pipe from the three supply wells, which were combined into a single line 

located in the existing underground portion of the treatment building. The single line 

extended up through an opening in the floor of the treatment building and connected 

to the 3-inch entry point of the treatment system. 

• Prechlorination. The existing sodium hypochlorite feed system was used to add 

chlorine ahead of the adsorption vessels to prevent biological growth in the vessels 

and maintain a target chlorine residual value of 0.5 mg/L in the distribution system 

for disinfection purposes. The chorine addition system consisted of a LMITM chlorine 

metering pump, a 50-gallon high-density polyethylene (HDPE) chemical feed tank, 

and polyethylene tubing to transfer the hypochlorite solution from the tank to the 

injection point. The sodium hypochlorite solution was injected directly into the raw 

water line after the wells were combined as described above. Operation of the 

chlorine feed system was tied to the well pumps so that the chlorine injected only 

when the wells were on. Chlorine consumption was measured using volumetric 

markings on the outside of the feed tank. 

15
16 

Figure 4-4. Schematic of G2 Media Adsorption System (Provided by ADI) 
Table 4-3. Design Specifications of the G2 Media System 

Parameter Value Remarks 

Adsorption Vessels 

Vessel Size (inch) 72 D × 72 H – 

Cross-Sectional Area (ft2

/vessel) 28.3 – 

Number of Vessels 2 – 

Configuration Series – 

Adsorptive Media 

Media Type G2 – 

Media Quantity (lbs) 8,000 4,000 lbs/vessel 

Media Volume (ft3

) 170 36-inch bed depth or 85 ft3/vessel 

Service 

System Flowrate (gpm) 40 System originally designed for 70 gpm at 

HAMHP in Allenstown, NH 

Hydraulic Loading Rate (gpm/ft2

) 1.4 – 

EBCT (min)/Vessel 16 Total EBCT for both vessels ~32 min 

Estimated Working Capacity (BV) 10,300 Vendor-provided estimate based on As 

breakthrough at 10 μg/L in lead vessel with 

incoming arsenic concentration at 39 μg/L 

in source water 

Throughput To Breakthrough (gal) 6,550,000 1 BV = 636 gal 

Average Use Rate (gal/day) 15,000 Based on ~6 hr of daily operation at 40 

gpm. 

Estimated Media Life (months) 14 Estimated frequency of media change-out 

in lead vessel based on average throughput 

to system. 

Pre-treatment NaClO Prechlorination 

H2SO4 pH adjustment before adsorption 

Post-treatment NaOH pH adjustment after adsorption 

Backwash 

Backwash Frequency As needed – 

Backwash Hydraulic Loading Rate 

(gpm/ft2

) 

4 – 

Backwash Flowrate (gpm) 115 – 

Backwash Duration (min/vessel) 10-15 – 

Wastewater Production (gal/vessel) 1,700 – 

• pH Adjustment Prior to Adsorption. The pH of the source water was adjusted 

using a 93% sulfuric acid from an average of 7.3 to a target value of 6.8 then 6.4 in 

order to increase the adsorption capacity of the media. The 93% sulfuric acid 

solution was delivered to the site in 15-gal containers (200 lb per container). The 

acid was metered directly from these containers to the injection point using a 

ProminentTM solenoid dosing pump. The acid was injected at a second injection point 

located on the raw water line (after the wells are combined) just downstream of the 

chlorine injection point described above. These injection points were installed about 

3 ft apart and approximately 25 ft upstream of the adsorption system. 

17
LEGEND

INFLUENT Unit Process

AP After pH Adjustment

BW Backwash Sampling Location

SS Sludge Sampling Location

Process Flow

Backwash Flow

DA: Cl2 Chlorine Disinfection

TB After Vessel B

TA After Vessel A

Water Sampling Locations

LEGEND

IN After Wells Combined

SURFACE DRAINAGE/

LEACH FIELD

BACKWASH DISPOSAL

INFLUENT

(WELLS 1, 2, AND 3)

pH ADJUSTMENT

H2SO4 INJECTION

DA: Cl2

BW

IN

SS

pH ADJUSTMENT

NaOH INJECTION

DISTRIBUTION SYSTEM

MEDIA 

VESSEL

B

MEDIA 

VESSEL

A

TA

TB

AP

LEGEND

INFLUENT Unit Process

AP After pH Adjustment

BW Backwash Sampling Location

SS Sludge Sampling Location

Process Flow

Backwash Flow

DA: Cl2 Chlorine Disinfection

TB After Vessel B

TA After Vessel A

Water Sampling Locations

LEGEND

IN After Wells Combined

LEGEND

18 

Figure 4-5. Process Flow Diagram and Sampling Locations 

pH(a), temperature(a), 

DO/ORP(a), As (total), 

Fe (total), Mn (total), SiO2, PO4, 

turbidity, alkalinity

 – 

Biweekly 

Bimonthly 

White Rock Water Company 

Public Water System in 

Bow, NH 

MEDIA G2® Technology 

Design Flow: 40 gpm 

TCLP 

Footnote 

(a) On-site analyses 

pH, TDS, turbidity, 

As (soluble), 

Fe (soluble), 

Mn (soluble)

 – 

pH(a), temperature(a), 

DO/ORP(a), As (total), 

Fe (total), Mn (total), SiO2, PO4, 

turbidity, alkalinity 

pH(a), temperature(a), 

DO/ORP(a), As (total), 

Fe (total), Mn (total), SiO2, PO4, 

turbidity, alkalinity 

pH(a), temperature(a), 

DO/ORP(a), As (total), 

Fe (total), Mn (total), SiO2, PO4, 

turbidity, alkalinity 

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

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

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

Mn (total and soluble), 

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

turbidity, alkalinity 

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

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

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

Mn (total and soluble), 

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

turbidity, alkalinity 

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

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

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

Mn (total and soluble), 

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

turbidity, alkalinity 

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

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

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

Mn (total and soluble), 

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

turbidity, alkalinity 

pH(a), temperature(a), 

DO/ORP(a), As (total),

Fe (total), Mn (total), SiO2, PO4, 

turbidity, alkalinity

INFLUENT Unit Process 

AP After pH Adjustment

BW Backwash Sampling Location

SS Sludge Sampling Location

Process Flow 

Backwash Flow 

DA: Cl2 Chlorine Disinfection 

TB After Vessel B

TA After Vessel A

Water Sampling Locations 

LEGEND 

IN After Wells Combined

SURFACE DRAINAGE/ 

LEACH FIELD 

BACKWASH DISPOSAL 

INFLUENT 

(WELLS 1, 2, AND 3) 

pH ADJUSTMENT 

H2SO4 INJECTION 

DA: Cl2 

BW 

IN 

SS 

pH ADJUSTMENT 

NaOH INJECTION 

DISTRIBUTION SYSTEM 

MEDIA 

VESSEL 

B 

MEDIA 

VESSEL 

A 

TA 

TB 

AP 

–

Biweekly

Bimonthly

White Rock Water Company

Public Water System in

Bow, NH

MEDIA G2® Technology

Design Flow: 40 gpm

TCLP

Footnote

(a) On-site analyses

pH, TDS, turbidity,

As (soluble),

Fe (soluble),

Mn (soluble)

 –

pH(a), temperature(a), 

DO/ORP(a), As (total),

Fe (total), Mn (total), SiO2, PO4, 

turbidity, alkalinity

pH(a), temperature(a), 

DO/ORP(a), As (total),

Fe (total), Mn (total), SiO2, PO4, 

turbidity, alkalinity

pH(a), temperature(a), 

DO/ORP(a), As (total),

Fe (total), Mn (total), SiO2, PO4, 

turbidity, alkalinity

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

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

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

Mn (total and soluble),

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

turbidity, alkalinity

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

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

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

Mn (total and soluble),

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

turbidity, alkalinity

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

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

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

Mn (total and soluble),

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

turbidity, alkalinity

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

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

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

Mn (total and soluble),

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

turbidity, alkalinity
• Arsenic Adsorption. The two 72-inch-diameter, 72-inch-sidewall-height vessels 

were constructed of 304 stainless steel and rated for 50 pounds per square inch (psi) 

working pressure. The system was delivered to the site with a pre-assembled pipe 

and valve manifold consisting of 3-inch schedule 80 PVC with flanged and solvent 

weld connections. The manifold was mounted directly on a uni-strut steel frame 

bolted directly to the front of the adsorption vessels as shown in Figure 4-6. Inlet and 

outlet pressure gauges, PVC manually-actuated butterfly valves, air release/vacuum 

valves, and sampling ports were installed as part of the pre-assembled unit. There 

were no automated controls included as part of the adsorption system; all valves were 

manually actuated. Initiation of system backwash or other operational adjustments 

required manual adjustment of valves. Two inline pH probes were installed in the 

piping manifold in order to measure the pH values of the water following the acid 

and caustic addition. Additionally, a pH chart recorder was installed for continuous 

logging of the inline probe readings. The addition of the acid and caustic was flow 

paced based on a 4-20 mA control signal from a flowmeter located on the treated 

water line downstream of the adsorption system. Each vessel contained about 85 ft3 

of G2 media. 

• pH Adjustment Prior to Storage and Distribution. After passing through the 

adsorption vessels, the pH values of the treated water were adjusted using a 25% 

NaOH solution to raise the pH value from about 6.5 to a target value of 7.5 before 

going to the storage tanks and distribution system. The pH was increased to reduce 

the tendency for dissolution of metals, especially lead and copper, from distribution 

piping. The 25% NaOH solution was delivered to the site in 15-gal containers (160 

lb per container). The caustic solution was metered directly from these containers to 

the injection point using a ProminentTM solenoid dosing pump. The injection point 

was located downstream of the adsorption system and before the treated water went 

out to the 15,000-gal storage tanks. 

Figure 4-6. ADI G2 Media Arsenic Adsorption System 

19
4.3 System Installation 

The installation of the treatment system at the site was completed in September 2004; shakedown and 

startup activities continued into October 2004. The system installation and building construction 

activities were carried out by the plant operator, C&C Water Services, as a subcontractor to ADI. 

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

Engineering, an ADI subcontractor located in Litchfield, NH. The plans included diagrams and 

specifications of the G2 media treatment system, as well as site drawings showing the proposed layout of 

the new treatment building. The plans were submitted to the NHDES (Water Supply Engineering 

Bureau) for review and approval on June 14, 2004. The NHDES issued a letter of approval on August 23, 

2004. The state did not issue a separate permit for discharging the system backwash water at the time of 

start-up. 

4.3.2 Building Construction. To house the G2 media treatment system, C&C Water Services 

constructed an aboveground addition to the existing underground pump house structure (Figure 4-1). 

Construction included placement of steel support beams on top of the existing concrete structure, and 

construction of a wood frame building on the steel supports. The new building is roughly the same size 

as the existing structure, approximately 20 ft by 22 ft. A photograph of the aboveground addition to the 

treatment building is shown in Figure 4-7. Building construction began on June 16, 2004 with placement 

of the steel support beams and continued through the end of August 2004, including placement and 

setting of the vessels, which were put into place before completing the walls and roof of the new 

treatment building. 

Figure 4-7. New Treatment Building Addition 

20
4.3.3 Installation, Shakedown, and Startup. The adsorption vessels arrived on site and were 

placed on the steel supports of the new treatment building on June 28, 2004. During shipment, some 

minor damage was made to welds on the bottom flanges of both vessels. The manufacturer arranged for 

repair of the welds by a local certified welding shop. C&C Water Services performed the system 

installation, including all plumbing, mechanical, and electrical work. Installation of system piping was 

completed on September 2, 2004. 

The G2 media was loaded into the vessels on September 13, 2004. Prior to system startup, the media was 

first backwashed at 115 gpm for about 1 hr to remove media fines in the bed. The G2 media was then 

conditioned using a downflow acid rinse to neutralize the pH of the media from about 12 as a result of the 

manufacturing process. To minimize the amount of wastewater produced, conditioning was done by 

recirculating the rinse water through each vessel at a flowrate of 70 gpm using a 5-hp pump. Meanwhile, 

a chemical metering pump was used to add a 93% sulfuric acid solution at the inlet of each vessel. Each 

vessel was conditioned separately for two 8-hr days and the total acid consumption was about 3 gal per 

vessel (or 6 gal total). The volume of wastewater produced per vessel was equivalent to the volume of 

water required to fill one vessel and some additional piping (i.e., about 1,500 gal). The wastewater (about 

3,000 gal per vessel over the two-day period) was discharged to a rip-rap lined surface drainage area near 

the treatment building at the end of each day. The pH of the wastewater as it was discharged ranged from 

about 10 on the first day to 7 on the second. 

Because of some delay in receiving the required components for the recirculation pump, the media 

conditioning did not begin until September 28, 2004 and continued for about four days. The system was 

put into service and the performance evaluation study officially began on October 13, 2004. A Battelle 

staff member visited the site on this date to inspect the system, provide operator training for data and 

sample collection, and collect the first set of samples from the treatment system. 

4.4 System Operation 

4.4.1 Operational Parameters. The operational parameters of the system are tabulated and 

attached as Appendix A. Key parameters are summarized in Table 4-4. From October 13, 2004 through 

April 24, 2005, the treatment system operated for 1,741 hr based on the well pump hour meter readings 

collected daily at the well head. The operational time represented a utilization rate of approximately 38% 

over the 28-week period with the supply wells operating at an average of 9.3 hr per day. The total system 

throughput from October 13, 2004 through April 24, 2005 was approximately 3,858,000 gal based on the 

flow totalizer readings from the finished water magnetic meter. This corresponds to 6,067 bed volumes 

(BVs) of water processed through the system. The average flowrate through the system was 40.8 gallons 

per minute (gpm) with an average EBCT of 31.7 min total or approximately 16 min per vessel. 

Pressure loss across the vessels averaged less than 1 psi across the lead vessel and less than 2 psi across 

the lag vessel for the first 28 weeks of operation. Because the pressure drop observed was low and did 

not change significantly during system operation, the system was backwashed only twice during this 

period. 

During the first 28 weeks of operation, the system experienced some operational problems with the inline 

pH meters. In general, the inline probe located after the acid addition upstream of the adsorption vessels 

read approximately 0.4 pH units lower than the corresponding measurements using a WTW field pH 

probe. The inline probe located after the caustic addition following the adsorption vessels typically read 

about 1.3 pH units higher than the corresponding measurements using the same field pH probe. The field 

21
Table 4-4. Summary of G2 Media Treatment System Operation 

Total Operating Time (hr) - 

October 13, 2004 to April 24, 2005 1741 

Average Daily Operating Time (hr/day) 9.3 

Throughput (kgal) 3,858 

Throughput (BV) 6,067 

Average Flowrate (gpm) 40.8 

Range of Flowrate (gpm) 10.6 – 49.0 

Average EBCT (min)(a) 31.7 

Range of EBCT (min)(a) 26 - 120 

Average Differential Pressure Loss across 

Vessel A (psi) 0.8 

Average Differential Pressure Loss across 

Vessel B (psi) 1.8 

(a) Calculated based on 170 ft3 of media total (85 ft3

 in each vessel; 

vessels in series). 

pH readings after caustic addition were, in most cases, close to the pH readings of distribution water 

samples measured by AAL (6.4 to 7.8 with the field probe vs. 6.6 to 8.1 in the distribution samples), 

suggesting that the field pH probe was more accurate than the inline probes. 

Although several attempts were made by the plant operator and ADI to correct the problems associated 

with the inline probes (including cleaning and calibrating the probes, consulting with the vendor and 

manufacturer, switching the “acid” inline probe [which seemed to read more accurately] with the 

“caustic” inline probe, and conducting an on-site service call by ADI to investigate and replace the “acid” 

inline probe with a new probe), correlation between the inline pH meters and the field meter continued to 

be poor throughout the first 28 weeks of operation. 

4.4.2 Backwash. During the first six months of system operation, the system was backwashed 

twice, one time each on January 11, 2005 and April 12, 2005 after about three and six months of system 

operation, respectively. Backwash was performed manually using finished water from the storage tanks. 

During backwash, the system was taken off-line and treated water was drawn via a booster pump from the 

storage tanks at a flowrate of approximately 115 gpm (or about 4 gpm/ft2

). The backwash lasted for 20 

and 10 min per vessel during the first and second backwash events, respectively, producing approximately 

2,200 and 1,200 gal of wastewater for each vessel. 

4.4.3 Residuals Management. Residuals produced by the operation of the treatment system 

include spent media and backwash water. The media was not exhausted during the first six months of 

system operation; therefore, the only residual produced was backwash water. Backwash water is 

discharged to a rip-rap lined surface drainage and allowed to infiltrate into the ground. 

4.4.4 System Operation Reliability and Simplicity. A significant O&M issue for this system was 

the need for acid and caustic addition to maintain the desired pH values of the feed water to the treatment 

system and the finished water to the distribution system. Confounding the proper dosing of acid and 

caustic were the continuing discrepancies observed in pH readings from the inline probes versus the field 

probe as discussed in Section 4.4.1. Further discussion on the impact of pH adjustment in the distribution 

system is included in Section 4.5.3. The system did not experience any unscheduled downtime during the 

first six months of operation. 

22
Additional discussion regarding system operation and operator skill requirements are provided below in 

relation to pre- and post-treatment requirements, levels of system automation, operator skill requirements, 

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

Pre- and Post-Treatment Requirements. Pre-treatment consisted of the addition of a 6% sodium 

hypochlorite solution for disinfection, which was already performed at the site prior to the installation of 

the arsenic treatment system, and a 93% sulfuric acid solution for lowering the water pH in order to 

maximize the arsenic removal capacity of the G2 media. Post-treatment included the addition of a 25% 

NaOH solution to raise the pH values back to approximately 7.5 to reduce corrosivity prior to entering the 

storage tanks and distribution system. The rate of chemical consumption is provided below under 

chemical handling and inventory requirements. 

System Controls. The G2 media adsorption system was a passive system, requiring only the operation of 

the well pumps and chemical metering pumps for chlorination and acid and caustic addition. The 

adsorption system itself required no automated parts and all valves were manually activated. Power 

supply to the chemical metering pumps was tied into the supply well pumps so that when the supply wells 

were started, triggered by a level switch in the storage tanks, the chemical metering pumps also were 

energized to dispense chlorine, acid, and caustic at a pre-determined rate. The system had the capability 

to adjust the chemical feed rates based on the inline probe readings to maintain a specified pH value; 

however, this control setup was disabled during the first 6 months of the demonstration period. The acid 

and caustic feed rates were controlled by manually setting the pump stroke-length and automatically 

pacing the pump based on a 4-20 mA control signal provided by a BadgerTM magnetic flowmeter located 

on the treated water line. Additionally, a two-pen pH chart recorder was installed for continuous logging 

of the pH values after the acid and caustic addition. Although useful for tracking the operation of the 

system, the pH chart recorder proved somewhat problematic to operate as it was initially installed without 

the proper relays to allow it to communicate with the inline pH probes. As a result, the system operated 

for several weeks with the pH recorder giving erroneous readings. In early January 2005, the proper 

relays were installed and the chart recorder was adjusted so that the readings better reflected the inline 

probe readings. However, the inline probes continued to give erroneous readings as described in Section 

4.4.1. Backwash cycles were initiated manually and required the operator to adjust system valves 

accordingly prior to initiating the system backwash. 

Operator Skill Requirements. Generally, the operation of the treatment system did not require additional 

skills beyond those necessary to operate the original treatment equipment used at the site prior to the 

demonstration. The daily demand on the system operator was typically about 20 minutes to visually 

inspect the system and record operating parameters such as totalizer and hour meter readings, flowrates, 

and system pressure readings on the field log sheets. Based on the size of the population served and the 

treatment technology, the State of New Hampshire requires Level 1A Certification for operation of the 

treatment system and is considering upgrading this requirement to Level 1 certification. 

In addition to the standard checks and data recording performed daily for the system, C&C water services 

personnel typically spent 3-4 hr per week troubleshooting various problems associated with the system, 

especially during the first few months of the system operation. Primarily this time was spent making 

adjustments to the acid and caustic addition. Because the system was not set to make these adjustments 

automatically, all adjustments were made by manually adjusting the stroke-length of the chemical 

metering pumps. Adding to the complexity of achieving the proper balance of acid and caustic addition 

was the disagreement in readings between the inline pH probes and the WTW field probe, as discussed in 

Section 4.4.1. In early December, acid addition was increased to further lower the pH of the feed water to 

attempt to increase arsenic removal by the G2 media. To counterbalance this increase in acid addition, 

intuitively, the caustic addition also would have to be increased. In fact, in late December, the caustic 

metering pump was inadvertently ramped down such that the pH values of water going to the storage 

23
tanks were lower than what had been measured historically at the site. The drop in pH values was 

noticeable in the subsequent distribution system samples collected on January 12, 2005. Further 

discussion on the impact of this pH drop in the distribution system is included in Section 4.5.3. 

Preventive Maintenance Activities. Regular maintenance activities required for the operation of the G2 

media treatment system consisted primarily of daily visual inspection of the system to ensure that it 

appeared to be operating appropriately, maintaining chemical supply for feed chemicals, collecting 

routine water samples, cleaning and calibrating the inline pH probes, and system backwashing as 

necessary. 

Chemical/Media Handling and Inventory Requirements. Chemicals required for system operation 

included a 6% sodium hypochlorite, a 93% sulfuric acid, and a 25% NaOH solution. Proper handling and 

storage of these chemicals were required, including secondary containment for the chemical storage area 

and proper safety equipment for plant operators, including eye wash station and use of personal protective 

equipment (gloves, chemical apron, and faceshield as required). During the first 28 weeks of system 

operation, approximately 11⁄2 to two 15-gal containers (160 lb per container) of 25% NaOH and one 15­

gal container (200 lb per container) of 93% sulfuric acid were consumed per month for pH control 

purposes. The average chemical consumption was 0.24 lb/1,000 gal of water treated for sulfuric acid and 

0.45 lb/1,000 gal for NaOH. 

Media change-out was not required during the first six months of operation; thus, no additional media 

handling was required after the initial installation. 

4.5 System Performance 

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

water from the treatment plant, backwash lines, and distribution system. 

4.5.1 Treatment Plant Sampling. Water samples were collected at four locations through the 

treatment train: at the inlet (IN), after chlorination and pH adjustment (AP), at the effluent of Vessel A 

(TA), and at the effluent of Vessel B (TB). Field-speciated samples at each location were collected once 

every eight weeks throughout this reporting period. Table 4-5 summarizes the arsenic, iron, and 

manganese analytical results. Table 4-6 summarizes the results of 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. The key parameter for evaluating the effectiveness of the G2 media treatment system was the 

concentration of arsenic in the treated water. The treatment plant water was sampled on 15 occasions 

during the first six months of system operation, with field speciation performed on four of the 15 

occasions. Samples were collected at all four sampling locations (IN, AP, TA, and TB) at each of the 15 

sampling events. 

Figure 4-8 contains four bar charts showing the concentrations of total As, particulate As, As(III), and 

As(V) at the IN, AP, TA , and TB locations for each of the four field speciation events. Total arsenic 

concentrations in raw water ranged from 38.0 to 91.3 μg/L and averaged 49.3 μg/L (Table 4-5). As(V) 

was the predominating species, ranging from 47.5 to 54.1 μg/L and averaging 50.9 μg/L. Only trace 

amounts of As(III) existed with concentrations averaging 0.6 μg/L. Particulate As also was low with 

concentrations typically less than 1 μg/L. During the system startup on October 13, 2004, an unusually 

high concentration of particulate As (i.e., greater than 40 μg/L, or almost 50% of total As) was measured. 

It was not clear why such a high particulate As concentration was detected during this sampling event. 

24
Table 4-5. Summary of Arsenic, Iron, and Manganese Analytical Results 

Parameter 

Sampling 

Location Units 

Number of 

Samples 

Minimum 

Concentration 

Maximum 

Concentration 

Average 

Concentration 

Standard 

Deviation 

IN μg/L 17(a) 38.0 91.3 49.3 11.7 

As (total) AP μg/L 17(a) 38.7 96.1 50.1 12.8 

TA μg/L 17(a) 12.6 37.5 -

(b) ­(b) 

TB μg/L 17(a) 1.7 50.9 -

(b) ­(b) 

IN μg/L 4 48.2 54.6 51.5 2.8 

As (total AP μg/L 4 49.7 55.7 53.0 2.6 

soluble) TA μg/L 4 15.5 25.3 -

(b) ­(b) 

TB μg/L 4 3.6 14.3 -

(b) ­(b) 

IN μg/L 4 <0.1 40.8 10.4 20.3 

As AP μg/L 4 <0.1 43.8 11.1 21.8 

(particulate) TA μg/L 4 <0.1 12.2 -

(b) ­(b) 

TB μg/L 4 <0.1 47.2 -

(b) ­(b) 

IN μg/L 4 0.5 0.7 0.6 0.1 

As(III) AP μg/L 4 0.5 0.6 0.6 0.1 

TA μg/L 4 0.4 0.8 -

(b) ­(b) 

TB μg/L 4 0.4 1.1 -

(b) ­(b) 

IN μg/L 4 47.5 54.1 50.9 2.9 

As(V) AP μg/L 4 49.1 55.1 52.5 2.7 

TA μg/L 4 14.8 24.5 -

(b) ­(b) 

TB μg/L 4 3.0 13.1 -

(b) ­(b) 

IN μg/L 17(a) <25 22.1 13.1 2.3 

Total Fe AP μg/L 17(a) <25 60.0 15.3 11.5 

TA μg/L 17(a) <25 <25 <25 0.0 

TB μg/L 17(a) <25 39.0 14.1 6.4 

IN μg/L 4 <25 <25 <25 0.0 

Dissolved Fe AP μg/L 4 <25 <25 <25 0.0 

TA μg/L 4 <25 <25 <25 0.0 

TB μg/L 4 <25 <25 <25 0.0 

IN μg/L 17(a) 0.12 2.0 0.9 0.6 

Total Mn AP μg/L 17(a) <0.1 7.2 1.4 1.7 

TA μg/L 17(a) 0.49 27.0 -

(b) ­(b) 

TB μg/L 17(a) <0.1 35.8 -

(b) ­(b) 

IN μg/L 4 0.44 1.2 0.6 0.4 

Dissolved AP μg/L 4 0.32 1.0 0.6 0.3 

Mn TA μg/L 4 1.15 9.0 -

(b) ­(b) 

TB μg/L 4 1.32 12.5 -

(b) ­(b) 

(a) Including two duplicate samples 

(b) Average concentration and standard deviation not calculated. See Figures 4-9 and 4-10 for As and Mn 

breakthrough curves. 

Note: One-half of the detection limit was used for samples with concentrations less than the detection limit for 

calculations. Duplicate samples were included in the calculations. 

25
Table 4-6. Summary of Water Quality Parameter Measurements 

Parameter 

Sampling 

Location Units 

Number 

of 

Samples 

Minimum 

Concentration 

Maximum 

Concentration 

Average 

Concentration 

Standard 

Deviation 

IN mg/L 15(a)(b) 55 77 65.1 5.4 

Alkalinity AP mg/L 17(b) 28 61 -

(c) ­(c) 

TA mg/L 17(b) 29 62 -

(c) ­(c) 

TB mg/L 17(b) 28 68 -

(c) ­(c) 

IN mg/L 4 0.7 1.1 0.91 0.16 

Fluoride AP mg/L 4 0.7 1.0 0.93 0.14 

TA mg/L 4 0.7 1.1 0.87 0.17 

TB mg/L 4 0.3 0.8 0.66 0.25 

IN mg/L 4 11 24 14.3 6.5 

Sulfate AP mg/L 4 26 51 -

(c) ­(c) 

TA mg/L 4 12 48 -

(c) ­(c) 

TB mg/L 4 9.6 48 -

(c) ­(c) 

IN mg/L 17(b) <0.05 <0.06 0.03 0.00 

Orthophosphate 

(as PO4) 

AP mg/L 17(b) <0.05 <0.06 0.03 0.00 

TA mg/L 17(b) <0.05 <0.06 0.03 0.00 

TB mg/L 17(b) <0.05 <0.06 0.03 0.00 

IN mg/L 17(b) 18.7 21.4 19.7 0.7 

Silica 

AP mg/L 17(b) 18.5 21.4 19.8 0.7 

TA mg/L 17(b) 21.1 50.8 -

(c) ­(c) 

TB mg/L 17(b) 23.5 61.8 -

(c) ­(c) 

IN mg/L 4 0.2 1.0 0.41 0.40 

Nitrate (as N) AP mg/L 4 0.1 0.5 0.24 0.15 

TA mg/L 4 0.2 1.3 0.48 0.55 

TB mg/L 4 0.2 1.4 0.52 0.59 

IN NTU 17(b) <0.1 1.1 0.31 0.31 

Turbidity AP NTU 17(b) <0.1 0.5 0.18 0.16 

TA NTU 17(b) <0.1 0.6 0.16 0.16 

TB NTU 17(b) <0.1 0.5 0.20 0.16 

IN S.U. 15 6.8 7.8 7.3 0.21 

pH AP S.U. 15 6.1 7.8 -

(c) ­(c) 

TA S.U. 15 6.1 7.9 -

(c) ­(c) 

TB S.U. 15 6.1 8.0 -

(c) ­(c) 

IN oC 15 11.5 12.4 11.9 0.27 

Temperature AP oC 15 11.5 12.7 11.9 0.35 

TA oC 15 11.2 12.9 11.8 0.41 

TB oC 15 11.2 13.0 11.7 0.47 

IN mg/L 13 4.5 6.8 5.6 0.73 

Dissolved AP mg/L 13 2.9 5.6 4.2 0.65 

Oxygen TA mg/L 13 3.5 5.3 4.3 0.51 

TB mg/L 13 3.5 5.4 4.4 0.47 

IN mV 14 195 498 233 77.1 

ORP AP mV 14 190 607 435 172.8 

TA mV 14 183 610 471 172.7 

TB mV 14 173 608 484 158.8 

26
Table 4-6. Summary of Water Quality Parameter Measurements (Continued) 

Parameter 

Sampling 

Location Units 

Number 

of 

Samples 

Minimum 

Concentration 

Maximum 

Concentration 

Average 

Concentration 

Standard 

Deviation 

AP mg/L 15 0.1 0.7 0.3 0.2 

Free Cl2 TA mg/L 15 0.1 0.5 0.2 0.1 

TB mg/L 15 0.1 0.6 0.2 0.1 

AP mg/L 15 0.1 0.5 0.3 0.1 

Total Cl2 TA mg/L 15 0.1 0.4 0.2 0.1 

TB mg/L 15 0.1 0.5 0.2 0.1 

Total 

Hardness 

(as CaCO3) 

IN mg/L 4 84.0 163.3 108.7 36.7 

AP mg/L 4 81.5 128.5 100.5 20.0 

TA mg/L 4 85.0 166.6 111.6 37.3 

TB mg/L 4 86.8 101.8 94.2 7.1 

(a) Two outlying alkalinity values, 254 mg/L (as CaCO3) measured on November 16, 2004 and 120 mg/L (as 

CaCO3) measured on March 1, 2005, were excluded from this summary table. 

(b) Including two duplicate samples 

(c) Average concentration and stand deviation not calculated. See Figures 4-11 and 4-12 for alkalinity, sulfate, pH, 

and silica measurements. 

Note: One-half of the detection limit was used for samples with concentrations less than the detection limit for 

calculations. Duplicate samples were included in the calculations. 

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

the raw water sample collected on April 22, 2004 (Table 4-1). 

As expected, arsenic concentrations at the AP location were similar to those in the raw water. Because 

the majority of arsenic present in raw water was already in the As(V) oxidation state, chlorination had 

little or no effect on the concentration or oxidation state of arsenic entering the adsorption vessels. 

Similar to those at the IN location, total arsenic concentrations at the AP location ranged from 38.7 to 

96.1 μg/L and averaged 50.1 μg/L. 

Free and total chlorine levels were measured at the AP, TA, and TB locations. Free chlorine levels were 

measured at 0.1 to 0.7 mg/L at the AP location, with total chlorine levels ranging from 0.1 to 0.5 mg/L 

(Table 4-6). The residual chlorine levels measured after each vessel at the TA and TB locations were 

very similar to those measured at the AP location, indicating little or no chlorine consumption by the G2 

media. 

Total As concentrations after the lead (A) and lag (B) vessels are plotted against the BVs of water treated 

in Figure 4-9. The figure also shows the total As concentrations in the source water and after 

prechlorination and pH adjustment. After the lead vessel, greater than 30 μg/L of total As was 

unexpectedly detected in samples collected just after startup on October 13 and about one week later on 

October 19, 2004. After about 380 BVs of throughput, total As concentrations decreased to 12.6 to 15.6 

μg/L before beginning a steady increase at about 2,600 BVs to 26.3 μg/L by April 12, 2005. Total As 

concentrations after the lag vessel also were high during the first two weeks of system operation, with 

16.7 to 21.8 μg/L of arsenic measured on October 13 and October 19, 2004, respectively. Afterwards, 

the concentrations dropped to 1.7 μg/L after about 2,500 BVs and then increased steadily to 5.8 μg/L after 

about 5,700 BVs by April 12, 2005. 

Total As concentration measured after the lag vessel (B) on December 14, 2004 was unusually high at 

50.9 μg/L, of which 47.3 μg/L existed as particulate As (See Figure 4-8). It was not clear what caused the 

elevated particulate As concentration. 

27
Arsenic Species at the Inlet (IN) Arsenic Species after Lead Vesse

100 100

As Concentration (μg/L) As Concentration (

μg/L) 

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

20

1020

10

0 0 

10/13/2004 12/14/2004 2/1/2005 3/29/2005 10/13/2004 12/14/2004 2/1/2005 

Date Date 

Arsenic Species after Chlorination and pH Adjustment (AP) Arsenic Species after Lag Vessel 

100 100

90 9080 80

As Concentration (μg/L) As Concentration (

μg/L) 70 70

60 6050 5040 4030 30

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

20 2010 10

0 

10/13/2004 12/14/2004 2/1/2005 3/29/2005 10/13/2004 12/14/2004 2/1/2005 

0 

Date Date 

90 9080 8070 7060 6050 50

40 4030 30

28

Figure 4-8. Concentration of Arsenic Species at the IN, AP, TA, and TB Sampling Locations 
Total Arsenic Results for Bow, NH 

20 

10 

0 

0 1 2 3 4 5 6 

Inlet 

After Prechlorination 

Vessel A 

Vessel B 

Bed Volumes of Water Treated (*103

) 

Figure 4-9. Total Arsenic Breakthrough Curves 

ADI attributed the elevated arsenic concentrations just after system startup to the leaching of arsenic from 

the G2 media prepared with FeCl3 containing arsenic and manganese as impurities. While this might 

explain the elevated arsenic levels observed in the treated water during the first two weeks of system 

operation, it did not explain why the arsenic concentrations remained high (i.e., 12.6 μg/L or greater) 

following the lead vessel throughout the first six months of system operation. 

Iron. Iron concentrations in the source water were low. With the exception of only a few data points, the 

iron concentrations, both total and dissolved, were less than the detection limit of 25 μg/L at all sampling 

locations throughout the first 6 months of system operation (Table 4-5). 

Manganese. Treatment plant water samples were analyzed for total Mn during all sampling events and 

for soluble Mn during speciation sampling events. Figure 4-10 shows the total manganese concentrations 

over time at each of the four sampling locations across the treatment train. Similar to iron, manganese 

concentrations in the raw water were low, ranging from 0.12 to 2.0 μg/L (Table 4-5). However, 

manganese concentrations in the treated water following the lead and lag vessels were significantly 

elevated to over 35 μg/L after the system start-up, apparently due to the leaching of manganese from the 

media. After about 3,000 BVs, manganese concentrations following the lead and lag vessels decreased to 

levels similar to those in the raw water. 

Other Water Quality Parameters. The results of other water quality parameters are included in Appendix 

B and are summarized in Table 4-6. Figure 4-11 presents the results of pH, alkalinity, and sulfate 

measurements collected across the treatment train. 

The first few samples taken during October 13 through November 2, 2004 showed somewhat erratic pH 

results across the treatment train, which were thought to have been caused, in part, by erroneous on-site As Concentration (μg/L) 100 

90 

80 

70 

60 

50 

40 

30 

29
Total Manganese Results for Bow, NH 

Mn Concentration (μg/L) 40 

35 

30 

25 

20 

15 

10 

5 

Inlet 

After Prechlorination 

Vessel A 

Vessel B 

0 

10/10/04 10/31/04 11/21/04 12/12/04 1/2/05 1/23/05 2/13/05 3/6/05 3/27/05 4/17/05 

Date 

Figure 4-10. Total Manganese Concentrations Over Time 

measurements using the WTW handheld meter. The plant operators were retrained for the use of the 

meter on November 9, 2004 and the results obtained since then appeared to follow a steadier trend. 

The pH values of the source water typically ranged from 7.3 to 7.5. At the suggestion of ADI, the target 

pH value for the feed water was set at 6.8 at the system start up and then reduced to 6.4 by mid-November 

2004. The target pH value for the treated water following caustic addition was set at 7.5. For the most 

part, the measured pH values after the acid addition and after Vessels A and B were very close to the 

target value of 6.8 and later 6.4. The measured pH values after the caustic addition, however, deviated by 

as much as 1.0 pH unit from the target value of 7.5. As described under Operator Skill Requirements in 

Section 4.4.4, the operator had some difficulties in adjusting the rate of caustic addition to account for the 

increased acid addition. 

From early December 2004 through April 2005, the sulfuric acid consumed to lower the pH of the source 

water from 7.5 to 6.4 was 0.26 lb/1,000 gal of water treated (or 31 mg/L) based on the amount of acid 

used and the volume of water treated during this period. This consumption rate matched that of a 

theoretical calculation using the method described by Rubel (2003) as shown in Table 4-7. 

Alkalinity readings of the source water ranged from 55 to 77 mg/L (as CaCO3) and averaged 65.1 mg/L. 

After the acid addition, the decreases in alkalinity ranged from 24 to 38 mg/L (as CaCO3) and averaged 

31.8 mg/L (as CaCO3). This amount matched the 30 mg/L (as CaCO3) decrease as shown in Table 4-7. 

Sulfate concentrations in the source water ranged from 11 to 24 mg/L and averaged 14.3 mg/L. 

Immediately after the system start up, sulfate concentrations were reduced to 12.0 and 9.6 mg/L following 

the lead and lag vessels, respectively, apparently being removed by the G2 media. Since the adjustment 

30
pH Values for Bow, NH 

5.5 

6.0 

6.5 

7.0 

7.5 

8.0 

8.5 

9.0 

pH 

Inlet 

After Acid Addition 

Vessel A 

Vessel B 

After Caustic Addition 

10/10/04 10/31/04 11/21/04 12/12/04 1/2/05 1/23/05 2/13/05 3/6/05 3/27/05 4/17/05 

Date 

Alkalinity Values for Bow, NH 

0 

10 

20 

30 

40 

50 

60 

70 

80 

90 

100 

Alkalinity (mg/L as CaCO3 ) 

Inlet 

After Acid Addition 

Vessel A 

Vessel B 

10/10/04 10/31/04 11/21/04 12/12/04 1/2/05 1/23/05 2/13/05 3/6/05 3/27/05 4/17/05 

Date 

Sulfate Values for Bow, NH 

60 

Inlet 

50 

40 

30 

20 

10 

0 

After Acid Addition 

Vessel A 

Vessel B 

Sulfate (mg/L) 10/10/04 10/31/04 11/21/04 12/12/04 1/2/05 1/23/05 2/13/05 3/6/05 3/27/05 4/17/05 

Date 

Figure 4-11. pH, Alkalinity, and Sulfate Values over Time 

31 
Table 4-7. Calculation of Acid Consumption for pH Adjustment at the WRWC Site 

Parameter Raw Water 

After pH 

Adjustment 

pH (S.U.) 7.5 6.4 

Total Alkalinity (mg/L as CaCO3) 70 40 

Free CO2 (mg/L) 4.2 31 

Total Alkalinity Reduction (mg/L as CaCO3) 30 

Acid Required (meq/L) 0.6 

93% Sulfuric Acid Required (mg/L) 31 

93% Sulfuric Acid Required (lb/1,000 gal) 0.26 

of the source water pH to 6.4 in mid-December 2004, increases in sulfate concentration averaged 34 

mg/L. This amount closely matched the 31 mg/L derived from the actual acid consumption and the 

theoretical calculation shown in Table 4-7. 

Figure 4-12 shows the silica concentrations (as SiO2) over time across the treatment train. Silica 

concentrations in the source water ranged from 18.7 to 21.4 mg/L, which were similar to those in samples 

collected at the AP location following chlorination and pH adjustment. Elevated silica concentrations as 

high as 61.8 mg/L were measured in the treated water following the lead and lag vessels. The increase in 

silica concentration was attributed to the G2 media which, as discussed in Section 4.2, is a silica based 

material. The leaching of silica from both vessels leveled off after about 2,000 BVs, but continued 

throughout the remainder of the study period with increase in concentrations ranging from 1.6 to 3.0 mg/L 

after the lead vessel and from 3.7 to 6.2 mg/L after the lag vessel. 

Silica Results for Bow, NH 

Vessel B 

10/10/04 10/31/04 11/21/04 12/12/04 1/2/05 1/23/05 2/13/05 3/6/05 3/27/05 4/17/05 

Date 

0 

10 

20 

30 

40 

50 

60 

70 

80 

Silica Concentration (mg/L as SiO2 ) 

Inlet 

After Prechlorination 

Vessel A 

Figure 4-12. Silica Concentrations Over Time 

32
Total hardness results ranged from 81.5 to 166.6 mg/L as CaCO3. Hardness, which was predominantly 

calcium hardness, was consistent across the treatment train and did not appear to be affected by any of the 

steps involved in the treatment process. Fluoride concentrations ranged from 0.3 to 1.1 mg/L. 

Orthophosphate was below the detection limit in all samples collected during this period. Nitrate (as N) 

ranged from 0.1 to 1.4 mg/L. 

Free and total chlorine was measured at the AP, TA, and TB sampling locations. Typically, free chlorine 

levels were measured at 0.1 to 0.7 mg/L at the AP location, with total chlorine levels ranging from 0.1 to 

0.5 mg/L. Residual chlorine levels measured at the TA and TB locations were similar to those measured 

at the AP location, indicating little or no chlorine consumption by the G2 media. 

DO levels ranged from 2.9 to 6.8 mg/L across the treatment train and were consistent at each location. 

ORP readings at the IN location varied from 195 to 498 mV and averaged 233 mV. After chlorination, 

the ORP readings increased significantly, ranging from 173 to 610 mV and averaging 435, 471, and 484 

mV, respectively, at the AP, TA, and TB locations. 

4.5.2 Backwash Water Sampling. Backwash water was sampled on January 11 and April 12, 

2005. Samples were collected from the sample port located in the backwash effluent discharge line from 

each vessel. Unfiltered samples were analyzed for pH, turbidity, and TDS. Filtered samples (using 0.45­

μm disc filters) were analyzed for soluble As, Fe, and Mn. Soluble iron was below the detection limit in 

each of the samples collected; soluble manganese concentrations also were low, comparable to the levels 

observed in the raw water. Soluble As concentrations in the Vessel A backwash water were 40.3 to 42.8 

μg/L, similar to the levels measured in the source water. Soluble As concentrations in the Vessel B 

backwash water were lower, ranging from 11.4 to 26.1 μg/L. Because finished water was used for 

backwash, these concentrations suggest that some arsenic might have been desorbed from the media 

during backwashing. The analytical results from the two backwash water sampling events are 

summarized in Table 4-8. Note that future backwash samples collected during the remainder of this 

demonstration study will include collection and analysis of total suspended solids (TSS) and total As, Fe, 

and Mn. These parameters were not included in the sampling performed during the first six months of 

system operation. 

Table 4-8. Backwash Water Sampling Results 

Date 

pH Turbidity TDS 

Soluble 

As(a) 

Soluble 

Fe(a) 

Soluble 

Mn(a) 

S.U. NTU mg/L μg/L μg/L μg/L 

Vessel 01/11/05 6.9 140 38.0 40.3 <25 0.8 

A 04/12/05 6.2 200 244 42.8 <25 2.0 

Vessel 01/11/05 6.7 390 72.0 11.4 <25 2.3 

B 04/12/05 6.6 120 240 26.1 <25 0.7 

(a) Filtered (0.45 μm) samples. 

4.5.3 Distribution System Water Sampling. Distribution system samples were collected to 

investigate if the water treated by the arsenic removal system would impact the lead and copper level and 

water chemistry in the distribution system. Prior to the installation and operation of the system, baseline 

distribution system water samples were collected at three homes on July 21, August 5, August 18, and 

September 8, 2004. Following the installation of the system, distribution system water sampling 

continued on a monthly basis at the same three locations. The samples were analyzed for pH, alkalinity, 

33
arsenic, iron, manganese, lead, and copper. The results of the distribution system sampling are 

summarized in Table 4-9. 

As expected, prior to the installation of the arsenic removal system, arsenic concentrations in the 

distribution system were similar to those measured in the raw water, ranging from 36.9 to 52.3 μg/L. 

After the treatment system was installed and put into service, arsenic concentrations in the distribution 

system decreased significantly and closely mirrored those measured after the treatment system at 

sampling location TB, ranging from 3.9 to 12.4 μg/L. 

Iron concentrations were similar to those observed in the raw water, and were typically below the 

detection limit of 25 μg/L. The iron concentration in the sample collected on January 12, 2005 at the DS1 

location was high; it was not clear why this concentration was significantly higher than the other relevant 

data points. 

Manganese concentrations in the distribution system generally followed those measured after the lag 

vessel with the highest concentrations (i.e., 16.0 μg/L) observed soon after the system was installed. 

Sampling location DS2 did not show as significant an increase in the manganese levels. The manganese 

concentrations declined steadily to levels only slightly higher than those observed during the baseline 

sampling after about three months of system operation (or about 2,500 BVs). 

The pH values measured during the baseline sampling ranged from 7.2 to 7.8. After the system was 

installed, the pH values ranged from 6.6 to 8.1. The pH values across all three locations were high during 

the sampling event on December 8, 2004. During the next sampling event on January 12, 2005, however, 

the pH values were significantly lower, ranging from 6.6 to 6.8. This swing in pH was likely caused by 

difficulties encountered with adjustments to the rate of caustic addition as described under Operator Skill 

Requirements in Section 4.4.4. The lower pH values appeared to have had a significant impact on the 

lead and copper levels in the distribution system. Prior to the January 2005 sampling event, the lead and 

copper levels measured at the three sampling locations ranged from 1.4 to 2.4 μg/L for lead and from 35.4 

to 147.0 μg/L for copper, which were consistent with the baseline values of 0.8 to 4.6 μg/L for lead and 

62.1 to 240.1 μg/L for copper. With the pH drop in January 2005, the lead concentration increased to 9.9 

μg/L at the DS3 location; and copper levels increased across all three sampling locations, with the most 

noticeable increase exceeding the action level of 1.3 mg/L at the DS3 location. During the subsequent 

monthly sampling events, the pH values were better controlled; however, the lead and copper levels 

continued to be higher than those observed before the pH drop in January. 

For the most part, alkalinity levels were consistent throughout the baseline sampling and five of the six 

monthly sampling events, ranging from 54 to 80 mg/L (as CaCO3). In January 2005, alkalinity values 

were lower (i.e., 43 to 55 mg/L), consistent with the low pH values measured during this sampling event. 

4.6 System Costs 

The cost-effectiveness of the system is evaluated based on the dollar cost per 1,000 gal of water treated. 

This includes the tracking of capital costs such as equipment, engineering, and installation costs and 

O&M costs such as 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 $154,700 (see Table 4-10). The equipment costs were $102,600 (or 66% of the total capital 

investment), which included $76,100 for the adsorption system (vessels and piping), $6,000 for the G2 

media (i.e., $35/ft3

 or $0.75/lb to fill two vessels), $3,900 for the backwash booster pump, and vendor’s 

labor and travel for the system shakedown and startup. 

34
35

Table 4-9. Distribution System Sampling Results 

No. of 

Sampling 

Events 

Sampling 

Location DS1 DS2 

Sampling Date 

Stagnation Time (hrs)

pH

Alkalinity

Total As

Total Fe

Total Mn

Total Pb

Total Cu

Stagnation Time (hrs)

pH

Alkalinity

Total As

Total Fe

Total Mn

Total Pb

Total Cu

Stagnation Time (hrs)

pH

Alkalinity

BL1 07/21/04 8.5 7.4 80 44.1 <25 1.1 2.5 93.7 7.8 7.4 68 41.1 <25 0.5 1.1 163.5 6.3 7.4 60 4

BL2 08/05/04 7.5 7.2 68 52.3 <25 5.0 4.6 88.7 8.0 7.2 66 45.8 <25 0.6 2.7 240.1 7.0 7.3 60 4BL3 08/18/04 7.0 7.7 60 36.9 28 0.7 1.9 122.2 7.5 7.6 60 41.3 38 1.8 3.8 62.8 7.0 7.6 60 3

BL4 09/08/04 9.3 7.8 64 51.0 <25 0.9 0.8 92.7 7.8 7.8 64 49.1 <25 0.5 0.8 75.9 8.2 7.7 64 5

1 11/03/04(a) 8.8 7.5 62 11.2 <25 11.7 1.5 107.0 8.8 7.6 66 8.5 <25 3.0 0.8 94.9 8.3 7.8 62 9

2 12/08/04 10.0 8.1 61 5.6 <25 7.5 0.9 35.4 7.8 8.1 61 12.4 <25 2.4 1.6 111.0 8.8 8.0 61 9

3 01/12/05 9.0 6.8 44 3.9 174/ 257 7.7 3.1 375.0/ 464.0 7.7 6.8 55 5.7 <25 3.5 3.7 747.0/ 844.0 10.7 6.6 43 5

4 02/09/05 5.5 7.5 54 4.4 <25 2.6 5.9 379.0 7.8 7.4 61 4.8 28 2.7 1.9 731.0 8.3 7.2 64 5

5 03/09/05 7.0 7.6 70 7.1 <25 2.1 1.6 56.0 7.7 7.4 57 5.3 <25 2.2 4.2 882.0 9.0 7.4 71 76 04/20/05 7.4 7.3 72 7.7 <25 2.6 3.7 262.1 7.7 7.1 67 4.2 <25 2.4 3.6 739.1 8.3 7.1 64 9

BL = baseline sampling DS = distribution sampling (a) Sample at DS2 was taken on November 8, 2004 (/) indicates laboratory re-run data with original result/re-run result Lead action level = 15 μg/L; copper action level = 1.3 mg/L The unit for analytical parameters is μg/L, except for pH (standard unit) and alkalinity (mg/L as CaCO3) 
Table 4-10. Capital Investment for the G2 Media Treatment System 

Description Quantity Cost 

% of Capital 

Investment Cost 

Equipment Costs 

Adsorption System 1 unit $76,100 – 

G2 Media 170 ft3

 $6,000 – 

Backwash Booster Pump 1 $3,900 – 

Field Services (Vendor Labor and Travel) – $16,600 – 

Equipment Total – $102,600 66% 

Engineering Costs 

Vendor Labor – $12,500 – 

Engineering Total – $12,500 8% 

Installation Costs 

Subcontractor – $32,500 – 

Vendor Labor – $3,550 – 

Vendor Travel – $3,550 – 

Installation Total – $39,600 26% 

Total Capital Investment – $154,700 100% 

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

the piping connections up to the distribution tie-in points, design of the electrical connections, and 

assembling and submission of the engineering plans for the permit application (Section 4.3.1). The 

engineering costs were $12,500, which was 8% of the total capital investment. 

The installation costs included the costs for the equipment and labor to unload and install the adsorption 

unit, perform the piping tie-ins and electrical work, and load and condition the media (Section 4.3.3). The 

installation was conducted by Lewis Engineering and C&C Water Services subcontracted to ADI. The 

installation costs were $39,600, or 26% of the total capital investment. 

C&C Water Services constructed an aboveground addition to the existing underground pump house 

structure to house the G2 media treatment system (Section 4.3.2). The cost of building the addition was 

approximately $25,000, including placement of a steel support on top of the existing concrete structure 

and construction of a wooden frame building on this steel support. 

The total capital cost of $154,700 and equipment cost of $102,600 were converted to a unit cost of 

$0.28/1,000 gallon and $0.19/1,000 gallon, respectively, using a capital recovery factor (CRF) 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 hr per day, 7 days per week at the original system design flowrate of 70 gpm. 

The system operated an average of 9.3 hr per day (see Table 4-4), producing 3,858,000 gal of water 

during the 6-month period, so the total unit cost and equipment-only unit cost were increased to 

$1.32/1,000 gallons and $0.83/1,000 gallons, respectively, at this reduced rate of usage. Using the 

system’s actual capacity of 40 gpm (57,600 gpd), the capital cost was $3,868/gpm ($2.68/gpd) and 

equipment-only cost was $2,565/gpm ($1.78/gpd). These calculations did not include the cost of the 

building construction. 

4.6.2 Operation and Maintenance Costs. O&M costs for the G2 media treatment system include 

only incremental costs associated with the adsorption system, such as media replacement and disposal, 

chemical supply, electricity, and labor. These costs are summarized in Table 4-11. Although media 

replacement and disposal did not take place during the first six months of operation, the cost to change 

out the lead vessel was estimated to be $9,396 based on information provided by the vendor and a local 

36
Table 4-11. O&M Costs for the G2 Media Treatment System 

Cost Category Value Assumptions 

Volume processed (kgal) 3,858 Through April 24, 2005 

Media Replacement and Disposal 

Media cost ($/ft3

) 40 Vendor quote 

Total media volume (ft3

) 85 Both vessels 

Media replacement cost ($) 3,400 Vendor quote 

Freight ($) 580 -

Labor cost ($) 4,226 Vendor quote 

Waste Analysis, TCLP ($) 300 -

Media disposal fee ($) 890 Vendor quote 

Subtotal $9,396 Vendor quote 

Media replacement and disposal cost 

($/1,000 gal) See Figure 4-13 

Based upon media run length at 10-μg/L 

arsenic breakthrough 

Chemical Usage 

Acid unit price ($/lb) 0.40 200 lb container at $80 

Acid consumption rate (lb/1,000 gal) 0.24 925 lb used to treat 3,858 kgal 

Acid cost ($/1,000 gal) 0.10 -

Caustic unit price ($/lb) 0.63 160 lb container at $100 

Caustic consumption rate 

(lb/1,000 gal) 0.45 1740 lb used to treat 3,858 kgal 

Caustic cost ($/1,000 gal) 0.28 -

Total chemical cost ($/1,000 gal) 0.38 

Cost for acid and caustic addition, no 

additional costs for chlorination 

Electricity 

Electricity cost ($/1,000 gal) $0.001 Electrical costs assumed negligible 

Labor 

Average weekly labor (hrs) 2.33 20 min/day 

Labor cost ($/1,000 gal) $0.34 Labor rate = $20/hr 

Total O&M cost ($/1,000 gal) See Figure 4-13 

Based upon media run length at 10-μg/L 

arsenic breakthrough 

subcontractor. This cost was used to estimate the media replacement cost per 1,000 gal of water treated 

as a function of the projected media run length to the 10-μg/L arsenic breakthrough (Figure 4-13). 

With a system that operates in series, the media in the lead vessel is ideally replaced when the arsenic 

concentration in the treated water following the lead vessel equals the incoming raw water concentration 

and before the arsenic concentration following the lag vessel reaches the 10-μg/L target value. Once the 

lead vessel is rebedded, the lead and lag vessels are switched, so that the lag vessel is placed in the lead 

position and the former lead vessel, now with new media, is placed in the lag position. This method 

maximizes the usage of the media so that the entire capacity for arsenic removal is exhausted before the 

media is replaced. 

Chemical costs included sodium hypochlorite for chlorination and sulfuric acid and NaOH for pH 

adjustment. Sodium hypochorite was in use prior to the installation of the G2 media treatment system for 

the purpose of maintaining chlorine residual in the distribution system. The treatment system did not 

37
$0.00 

$2.00 

$4.00 

$6.00 

$8.00 

$10.00 

$12.00 

$14.00 

$16.00 

Cost ($/1,000 gal) 

O&M Cost (including Media 

Replacement) 

Media Replacement Cost 

0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 11000 12000 

Media Working Capacity, Bed Volumes 

Figure 4-13. Media Replacement and O&M Costs 

change the use rate of the sodium hypochlorite solution. Therefore, the chemical cost related to the use of 

sodium hypochlorite was unchanged. During the first six months of system operation, 5 containers (15­

gal, 200 lb per container) of 93% sulfuric acid and 11 containers (15-gal, 160 lb per container) of 25% 

NaOH were consumed for pH adjustment. Based on the price per drum of approximately $80 and $100 

for acid and caustic, respectively, the total chemical cost for this period was about $1,500 or $0.38/1,000 

gallons. 

The electrical usage rate for the pump station averaged 131 kWh per day during the six-month study 

period. Comparison of electrical bills prior to system installation and since startup indicated that the 

treatment system did not cause a noticeable increase in power consumption. Therefore, electrical costs 

associated with operation of the G2 media treatment system were negligible. 

The routine, non-demonstration-related labor activities consumed about 20 minutes per day, as noted in 

Section 4.4.4. Therefore, the estimated labor cost is $0.34/1,000 gal of water treated. 

38
5.0 REFERENCES 

Battelle. 2003. Revised Quality Assurance Project Plan for Evaluation of Arsenic Removal Technology. 

Prepared under Contract No. 68-C-00-185, Task Order No. 0019, for U.S. EPA NRMRL. 

November 17. 

Battelle. 2004. Final System Performance Evaluation Study Plan: U.S. EPA Demonstration of Arsenic 

Removal Technology at Bow, New Hampshire. Prepared under Contract No. 68-C-00-185, Task 

Order No. 0019 for U.S. EPA NRMRL. October 6. 

Chen, A.S.C., L. Wang, J. Oxenham, and W. Condit. 2004. Capital Costs of Arsenic Removal 

Technologies: U.S. EPA Arsenic Removal Technology Demonstration Program Round 1. 

EPA/600/R-04/201. U.S. 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. 

EPA, see U.S. Environmental Protection Agency. 

Rubel, Jr., F. 2003. Design Manual: Removal of Arsenic from Drinking Water by Adsorptive Media. 

EPA/600/R-03/019. U.S. EPA NRMRL, Cincinnati, OH. 

U.S. Environmental Protection Agency. 2003. Minor Clarification of the National Primary Drinking 

Water Regulation for Arsenic. Federal Register, 40 CFR Part 141. March 25. 

U.S. Environmental Protection Agency. 2002. Lead and Copper Monitoring and Reporting Guidance 

for Public Water Systems. Prepared by EPA's Office of Water. EPA/816/R-02/009. February. 

U.S. Environmental Protection Agency. 2001. National Primary Drinking Water Regulations: Arsenic 

and Clarifications to Compliance and New Source Contaminants Monitoring. Fed. Register., 

66:14:6975. January 22. 

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. 

39
APPENDIX A 

OPERATIONAL DATA
EPA Arsenic Demonstration at WRWC in Bow, NH – Summary of Daily System Operational Data (Pa

A-1

Oulet Magnetic Meter Vessel A 

Cumulative 

Avg Cumulative Daily Cumulative Bed 

Operation Operation Outlet Outlet Flow Volume Volumes Inlet Outlet I

Week No. Date 

Hours Hours Flowrate Totalizer Totalizer Treated Treated Pressure Pressure 

Δp Pre

hr hr gpm gal gal gal psi psi psi 

10/11/2004 NA NA NM NM NA NA NA NM NM NA 

10/12/2004 6.7 6.7 NM NM NA NA NA 0 3 NA 10/13/2004 NA NA 36 537,160 NA NA NA 3 5 NA 

1 10/14/2004 NA NA NM NM NA NA NA NM NM NA 

10/15/2004 NA NA NM NM NA NA NA NM NM NA 10/16/2004 NA NA NM NM NA NA NA NM NM NA 10/17/2004 NA NA NM NM NA NA NA NM NM NA 

10/18/2004 NA NA NM NM NA NA NA NM NM NA 

10/19/2004 7.3 14.0 38.6 643,625 106,465 106,465 167 2.0 3.0 1.0 

10/20/2004 8.4 22.4 26.9 664,300 20,675 127,140 200 1.0 2.0 1.0 

2 10/21/2004 6.6 29.0 30.6 680,661 16,361 143,501 226 1.0 3.0 2.0 

10/22/2004 8.9 37.9 39.0 702,593 21,932 165,433 260 2.0 2.0 0.0 

10/23/2004 7.8 45.7 44.0 721,837 19,244 184,677 290 2.0 2.0 0.0 

10/24/2004 7.2 52.9 47.0 739,366 17,529 202,206 318 3.0 4.0 1.0 

10/25/2004 8.8 61.7 48.0 760,847 21,481 223,687 352 2.0 3.0 1.0 

10/26/2004 6.8 68.5 38.0 777,478 16,631 240,318 378 2.0 3.0 1.0 

10/27/2004 8.4 76.9 45.0 797,624 20,146 260,464 410 2.0 4.0 2.0 

3 10/28/2004 7.5 84.4 46.0 816,002 18,378 278,842 439 2.0 4.0 2.0 

10/29/2004 7.6 92.0 48.0 834,796 18,794 297,636 468 2.0 3.0 1.0 

10/30/2004 9.6 101.6 49.0 858,346 23,550 321,186 505 2.0 3.0 1.0 

10/31/2004 9.7 111.3 44.0 880,781 22,435 343,621 540 2.0 3.0 1.0 

11/1/2004 7.9 119.2 41.7 899,790 19,009 362,630 570 5.0 5.0 0.0 

11/2/2004 9.2 128.4 44.0 921,975 22,185 384,815 605 8.0 10.0 2.0 11/3/2004 6.9 135.3 44.0 938,108 16,133 400,948 631 8.0 10.0 2.0 

4 11/4/2004 8.6 143.9 43.0 957,946 19,838 420,786 662 8.0 10.0 2.0 

11/5/2004 8.8 152.7 43.3 978,591 20,645 441,431 694 8.0 10.0 2.0 

11/6/2004 8.1 160.8 41.0 997,718 19,127 460,558 724 8.0 8.0 0.0 11/7/2004 8.8 169.6 43.0 1,017,767 20,049 480,607 756 8.0 10.0 2.0 

11/8/2004 9.2 178.8 45.0 1,038,441 20,674 501,281 788 10.0 10.0 0.0 

11/9/2004 7.7 186.5 42.0 1,056,213 17,772 519,053 816 10.0 11.0 1.0 

11/10/2004 7.2 193.7 43.0 1,073,299 17,086 536,139 843 10.0 10.0 0.0 

5 11/11/2004 7.7 201.4 45.0 1,091,607 18,308 554,447 872 10.0 10.0 0.0 

11/12/2004 9.8 211.2 36.0 1,114,759 23,152 577,599 908 6.0 8.0 2.0 

11/13/2004 7.7 218.9 42.0 1,132,453 17,694 595,293 936 8.0 10.0 2.0 

11/14/2004 8.3 227.2 41.0 1,151,444 18,991 614,284 966 8.0 9.0 1.0 

11/15/2004 8.9 236.1 48.0 1,171,547 20,103 634,387 998 9.0 10.0 1.0 

11/16/2004 8.2 244.3 40.0 1,198,461 26,914 661,301 1040 12.0 12.0 0.0 

11/17/2004 7.9 252.2 42.0 1,208,577 10,116 671,417 1056 10.0 12.0 2.0 

6 11/18/2004 7.5 259.7 43.0 1,226,155 17,578 688,995 1084 12.0 12.0 0.0 

11/19/2004 8.6 268.3 41.0 1,246,352 20,197 709,192 1115 10.0 12.0 2.0 

11/20/2004 9.7 278.0 44.0 1,268,470 22,118 731,310 1150 10.0 11.0 1.0 

11/21/2004 8.4 286.4 40.0 1,286,856 18,386 749,696 1179 10.0 11.0 1.0 
EPA Arsenic Demonstration at WRWC in Bow, NH – Summary of Daily System Operational Data (Pa

A-2

Oulet Magnetic Meter Vessel A 

Cumulative 

Avg Cumulative Daily Cumulative Bed 

Operation Operation Outlet Outlet Flow Volume Volumes Inlet Outlet I

Week No. Date 

Hours Hours Flowrate Totalizer Totalizer Treated Treated Pressure Pressure 

Δp Pre

hr hr gpm gal gal gal psi psi psi 

11/22/2004 8.6 295.0 39.3 1,306,700 19,844 769,540 1210 10.0 11.0 1.0 

11/23/2004 7.3 302.3 40.3 1,323,674 16,974 786,514 1237 10.0 11.0 1.0 

11/24/2004 9.7 312.0 43.3 1,345,911 22,237 808,751 1272 11.0 12.0 1.0 

7 11/25/2004 8.2 320.2 41.7 1,364,685 18,774 827,525 1302 11.0 12.0 1.0 

11/26/2004 8.8 329.0 41.3 1,384,761 20,076 847,601 1333 12.0 12.0 0.0 

11/27/2004 8.4 337.4 40.3 1,403,810 19,049 866,650 1363 10.0 11.0 1.0 

11/28/2004 11.0 348.4 39.4 1,427,681 23,871 890,521 1401 10.0 11.0 1.0 

11/29/2004 7.6 356.0 40.1 1,444,834 17,153 907,674 1428 10.0 11.0 1.0 

11/30/2004 8.5 364.5 46.7 1,463,974 19,140 926,814 1458 12.0 13.0 1.0 

12/1/2004 7.1 371.6 41.5 1,480,492 16,518 943,332 1484 12.0 13.0 1.0 

8 12/2/2004 8.1 379.7 41.6 1,499,233 18,741 962,073 1513 12.0 13.0 1.0 

12/3/2004 9.1 388.8 38.2 1,520,747 21,514 983,587 1547 9.0 9.0 0.0 

12/4/2004 7.4 396.2 41.5 1,537,957 17,210 1,000,797 1574 10.0 10.0 0.0 

12/5/2004 9.2 405.4 42.5 1,558,903 20,946 1,021,743 1607 9.0 9.0 0.0 

12/6/2004 7.3 412.7 42.3 1,575,151 16,248 1,037,991 1633 12.0 12.0 0.0 12/7/2004 7.6 420.3 41.1 1,592,399 17,248 1,055,239 1660 12.0 12.0 0.0 

12/8/2004 7.7 428.0 43.8 1,610,551 18,152 1,073,391 1688 13.0 13.0 0.0 

9 12/9/2004 8.0 436.0 43.4 1,628,928 18,377 1,091,768 1717 13.0 13.0 0.0 

12/10/2004 8.2 444.2 43.7 1,648,334 19,406 1,111,174 1748 11.0 12.0 1.0 

12/11/2004 8.4 452.6 42.6 1,667,441 19,107 1,130,281 1778 12.0 12.0 0.0 

12/12/2004 10.2 462.8 36.8 1,690,927 23,486 1,153,767 1815 9.0 9.0 0.0 

12/13/2004 7.2 470.0 42.9 1,706,789 15,862 1,169,629 1840 13.0 12.0 1.0 

12/14/2004 9.4 479.4 45.5 1,728,436 21,647 1,191,276 1874 10.0 10.0 0.0 

12/15/2004 6.5 485.9 41.7 1,744,098 15,662 1,206,938 1898 9.0 9.0 0.0 

10 12/16/2004 7.0 492.9 43.4 1,760,533 16,435 1,223,373 1924 10.0 10.0 0.0 

12/17/2004 9.2 502.1 41.6 1,782,219 21,686 1,245,059 1958 8.0 8.0 0.0 

12/18/2004 8.1 510.2 41.3 1,800,894 18,675 1,263,734 1988 9.0 8.0 1.0 

12/19/2004 9.4 519.6 38.0 1,822,426 21,532 1,285,266 2021 7.0 7.0 0.0 

12/20/2004 9.1 528.7 41.6 1,842,688 20,262 1,305,528 2053 7.0 8.0 1.0 

12/21/2004 7.2 535.9 42.3 1,854,450 11,762 1,317,290 2072 10.0 10.0 0.0 

12/22/2004 8.7 544.6 41.4 1,878,671 24,221 1,341,511 2110 10.0 10.0 0.0 

11 12/23/2004 NA NA NM NM NA NA NA NM NM NA 

12/24/2004 20.8 565.4 41.8 1,924,958 NA NA NA 10.0 10.0 0.0 

12/25/2004 9.9 575.3 38.7 1,946,344 21,386 1,362,897 2144 10.0 9.0 1.0 

12/26/2004 10.6 585.9 40.6 1,969,074 22,730 1,385,627 2179 10.0 9.0 1.0 

12/27/2004 9.7 595.6 42.1 1,988,059 18,985 1,404,612 2209 9.0 9.0 0.0 

12/28/2004 8.8 604.4 39.5 2,008,591 20,532 1,425,144 2241 9.0 9.0 0.0 

12/29/2004 9.8 614.2 40.8 2,030,335 21,744 1,446,888 2276 8.0 7.0 1.0 

12 12/30/2004 10.1 624.3 36.5 2,052,360 22,025 1,468,913 2310 7.0 7.0 0.0 

12/31/2004 11.7 636.0 35.4 2,077,382 25,022 1,493,935 2350 7.0 7.0 0.0 

1/1/2005 7.4 643.4 38.5 2,093,961 16,579 1,510,514 2376 9.0 9.0 0.0 

1/2/2005 23.5 666.9 31.5 2,134,111 40,150 1,550,664 2439 6.0 4.0 2.0 
EPA Arsenic Demonstration at WRWC in Bow, NH – Summary of Daily System Operational Data (Pa

A-3

Oulet Magnetic Meter Vessel A 

Cumulative 

Avg Cumulative Daily Cumulative Bed 

Operation Operation Outlet Outlet Flow Volume Volumes Inlet Outlet I

Week No. Date 

Hours Hours Flowrate Totalizer Totalizer Treated Treated Pressure Pressure 

Δp Pre

hr hr gpm gal gal gal psi psi psi 

1/3/2005 7.3 674.2 40.3 2,149,653 15,542 1,566,206 2463 10.0 10.0 0.0 

1/4/2005 8.5 682.7 41.6 2,168,274 18,621 1,584,827 2493 11.0 10.0 1.0 

1/5/2005 8.1 690.8 43.0 2,186,659 18,385 1,603,212 2522 11.0 11.0 0.0 

13 1/6/2005 10.5 701.3 38.2 2,210,604 23,945 1,627,157 2559 7.0 7.0 0.0 

1/7/2005 8.9 710.2 40.6 2,229,746 19,142 1,646,299 2589 9.0 8.0 1.0 

1/8/2005 8.5 718.7 40.1 2,248,542 18,796 1,665,095 2619 10.0 10.0 0.0 

1/9/2005 9.6 728.3 44.3 2,269,572 21,030 1,686,125 2652 10.0 10.0 0.0 

1/10/2005 9.5 737.8 40.3 2,290,483 20,911 1,707,036 2685 9.0 8.0 1.0 

1/11/2005 12.4 750.2 31.5 2,317,137 26,654 1,733,690 2727 7.0 8.0 1.0 

1/12/2005 6.6 756.8 43.2 2,331,891 14,754 1,748,444 2750 15.0 15.0 0.0 

14 1/13/2005 9.4 766.2 40.3 2,352,893 21,002 1,769,446 2783 12.0 13.0 1.0 

1/14/2005 7.8 774.0 40.7 2,369,333 16,440 1,785,886 2809 15.0 15.0 0.0 1/15/2005 9.8 783.8 40.0 2,391,115 21,782 1,807,668 2843 14.0 15.0 1.0 1/16/2005 10.3 794.1 40.8 2,413,979 22,864 1,830,532 2879 12.0 13.0 1.0 1/17/2005 9.5 803.6 39.9 2,434,854 20,875 1,851,407 2912 11.0 13.0 2.0 1/18/2005 8.5 812.1 43.7 2,452,751 17,897 1,869,304 2940 15.0 16.0 1.0 1/19/2005 7.9 820.0 41.5 2,470,822 18,071 1,887,375 2969 14.0 15.0 1.0 

15 1/20/2005 8.6 828.6 40.3 2,490,330 19,508 1,906,883 2999 14.0 15.0 1.0 

1/21/2005 9.1 837.7 41.1 2,510,687 20,357 1,927,240 3031 12.0 13.0 1.0 

1/22/2005 9.4 847.1 40.4 2,531,399 20,712 1,947,952 3064 12.0 13.0 1.0 1/23/2005 9.6 856.7 42.7 2,552,097 20,698 1,968,650 3096 13.0 13.0 0.0 1/24/2005 9.1 865.8 41.3 2,571,909 19,812 1,988,462 3127 14.0 15.0 1.0 1/25/2005 8.1 873.9 40.1 2,590,546 18,637 2,007,099 3157 15.0 16.0 1.0 1/26/2005 8.0 881.9 42.2 2,608,795 18,249 2,025,348 3186 15.0 16.0 1.0 

16 1/27/2005 8.4 890.3 44.3 2,627,629 18,834 2,044,182 3215 16.0 16.0 0.0 

1/28/2005 10.1 900.4 38.2 2,650,511 22,882 2,067,064 3251 11.0 12.0 1.0 

1/29/2005 8.0 908.4 37.0 2,668,851 18,340 2,085,404 3280 11.0 12.0 1.0 1/30/2005 12.3 920.7 34.0 2,695,129 26,278 2,111,682 3321 8.0 8.0 0.0 

1/31/2005 8.0 928.7 39.6 2,711,222 16,093 2,127,775 3347 16.0 16.0 0.0 

2/1/2005 7.9 936.6 42.4 2,729,013 17,791 2,145,566 3375 15.0 16.0 1.0 2/2/2005 8.3 944.9 37.3 2,747,686 18,673 2,164,239 3404 16.0 16.0 0.0 

17 2/3/2005 8.3 953.2 45.9 2,766,522 18,836 2,183,075 3434 16.0 16.0 0.0 

2/4/2005 8.7 961.9 39.5 2,786,021 19,499 2,202,574 3464 16.0 16.0 0.0 2/5/2005 9.8 971.7 45.7 2,807,547 21,526 2,224,100 3498 15.0 15.0 0.0 2/6/2005 11.3 983.0 36.8 2,831,725 24,178 2,248,278 3536 10.0 10.0 0.0 

2/7/2005 7.5 990.5 40.7 2,848,555 16,830 2,265,108 3563 16.0 16.0 0.0 2/8/2005 7.9 998.4 41.1 2,866,591 18,036 2,283,144 3591 16.0 16.0 0.0 2/9/2005 8.4 1006.8 47.2 2,885,410 18,819 2,301,963 3621 16.0 16.0 0.0 

18 2/10/2005 9.1 1015.9 43.1 2,906,231 20,821 2,322,784 3653 13.0 13.0 0.0 

2/11/2005 8.9 1024.8 39.7 2,925,923 19,692 2,342,476 3684 13.0 13.0 0.0 

2/12/2005 9.9 1034.7 33.6 2,948,119 22,196 2,364,672 3719 11.0 12.0 1.0 

2/13/2005 10.0 1044.7 38.8 2,969,745 21,626 2,386,298 3753 13.0 13.0 0.0 
EPA Arsenic Demonstration at WRWC in Bow, NH – Summary of Daily System Operational Data (Pa

A-4

Oulet Magnetic Meter Vessel A 

Cumulative 

Avg Cumulative Daily Cumulative Bed 

Operation Operation Outlet Outlet Flow Volume Volumes Inlet Outlet I

Week No. Date 

Hours Hours Flowrate Totalizer Totalizer Treated Treated Pressure Pressure 

Δp Pre

hr hr gpm gal gal gal psi psi psi 

2/14/2005 8.9 1053.6 39.9 2,989,704 19,959 2,406,257 3785 13.0 13.0 0.0 

2/15/2005 7.8 1061.4 40.1 3,007,034 17,330 2,423,587 3812 10.0 9.0 1.0 

2/16/2005 8.4 1069.8 40.3 3,026,039 19,005 2,442,592 3842 10.0 9.0 1.0 

19 2/17/2005 8.5 1078.3 41.0 3,045,281 19,242 2,461,834 3872 10.0 9.0 1.0 

2/18/2005 9.1 1087.4 41.2 3,066,022 20,741 2,482,575 3905 9.0 8.0 1.0 

2/19/2005 11.0 1098.4 36.0 3,090,622 24,600 2,507,175 3943 7.0 7.0 0.0 

2/20/2005 11.0 1109.4 38.9 3,114,486 23,864 2,531,039 3981 7.0 7.0 0.0 

2/21/2005 8.6 1118.0 44.0 3,133,287 18,801 2,549,840 4010 9.0 8.0 1.0 

2/22/2005 9.1 1127.1 39.9 3,153,152 19,865 2,569,705 4042 20.0 21.0 1.0 

2/23/2005 10.4 1137.5 39.3 3,175,292 22,140 2,591,845 4077 19.0 19.0 0.0 

20 2/24/2005 9.6 1147.1 42.1 3,195,313 20,021 2,611,866 4108 19.0 19.0 0.0 

2/25/2005 10.5 1157.6 41.2 3,217,543 22,230 2,634,096 4143 21.0 22.0 1.0 

2/26/2005 12.5 1170.1 42.2 3,243,080 25,537 2,659,633 4183 17.0 18.0 1.0 

2/27/2005 11.4 1181.5 38.0 3,266,391 23,311 2,682,944 4220 17.0 17.0 0.0 

2/28/2005 9.1 1190.6 42.9 3,285,641 19,250 2,702,194 4250 20.0 20.0 0.0 

3/1/2005 10.0 1200.6 38.0 3,307,138 21,497 2,723,691 4284 16.0 16.0 0.0 

3/2/2005 10.4 1211.0 36.4 3,329,356 22,218 2,745,909 4319 16.0 16.0 0.0 

21 3/3/2005 8.0 1219.0 41.3 3,346,888 17,532 2,763,441 4346 20.0 20.0 0.0 

3/4/2005 11.5 1230.5 35.5 3,371,421 24,533 2,787,974 4385 15.0 15.0 0.0 

3/5/2005 11.0 1241.5 39.4 3,394,246 22,825 2,810,799 4421 17.0 18.0 1.0 

3/6/2005 13.2 1254.7 35.6 3,420,533 26,287 2,837,086 4462 15.0 16.0 1.0 

3/7/2005 10.6 1265.3 40.3 3,441,728 21,195 2,858,281 4496 19.0 19.0 0.0 

3/8/2005 13.2 1278.5 37.8 3,467,373 25,645 2,883,926 4536 17.0 18.0 1.0 

3/9/2005 14.1 1292.6 39.3 3,494,579 27,206 2,911,132 4579 17.0 18.0 1.0 

22 3/10/2005 14.1 1306.7 37.2 3,521,436 26,857 2,937,989 4621 25.0 25.0 0.0 2

3/11/2005 14.3 1321.0 38.4 3,548,297 26,861 2,964,850 4663 22.0 23.0 1.0 3/12/2005 11.0 1332.0 38.7 3,568,879 20,582 2,985,432 4696 27.0 28.0 1.0 2

3/13/2005 11.0 1343.0 42.6 3,590,313 21,434 3,006,866 4729 27.0 28.0 1.0 2

3/14/2005 8.2 1351.2 36.4 3,606,707 16,394 3,023,260 4755 NA 27.0 NA 2

3/15/2005 9.1 1360.3 44.3 3,625,853 19,146 3,042,406 4785 20.0 21.0 1.0 

3/16/2005 8.1 1368.4 43.0 3,643,284 17,431 3,059,837 4813 22.0 22.0 0.0 

23 3/17/2005 8.4 1376.8 42.6 3,661,488 18,204 3,078,041 4841 22.0 23.0 1.0 

3/18/2005 8.7 1385.5 41.7 3,680,954 19,466 3,097,507 4872 17.0 17.0 0.0 

3/19/2005 9.2 1394.7 40.3 3,700,919 19,965 3,117,472 4903 15.0 16.0 1.0 

3/20/2005 10.7 1405.4 42.3 3,723,897 22,978 3,140,450 4939 12.0 13.0 1.0 

3/21/2005 8.0 1413.4 44.5 3,740,922 17,025 3,157,475 4966 21.0 22.0 1.0 

3/22/2005 8.0 1421.4 47.7 3,758,479 17,557 3,175,032 4994 22.0 27.0 5.0 

3/23/2005 9.8 1431.2 43.6 3,780,333 21,854 3,196,886 5028 15.0 15.0 0.0 

24 3/24/2005 7.1 1438.3 42.5 3,796,412 16,079 3,212,965 5053 16.0 16.0 0.0 

3/25/2005 9.5 1447.8 36.7 3,817,763 21,351 3,234,316 5087 13.0 13.0 0.0 

3/26/2005 9.8 1457.6 42.9 3,838,499 20,736 3,255,052 5120 15.0 15.0 0.0 

3/27/2005 13.2 1470.8 35.7 3,866,379 27,880 3,282,932 5163 10.0 9.0 1.0 
EPA Arsenic Demonstration at WRWC in Bow, NH – Summary of Daily System Operational Data (Pa

A-5

Oulet Magnetic Meter Vessel A 

Cumulative 

Avg Cumulative Daily Cumulative Bed 

Operation Operation Outlet Outlet Flow Volume Volumes Inlet Outlet I

Week No. Date 

Hours Hours Flowrate Totalizer Totalizer Treated Treated Pressure Pressure 

Δp Pre

hr hr gpm gal gal gal psi psi psi 

3/28/2005 8.2 1479.0 37.8 3,883,085 16,706 3,299,638 5190 15.0 16.0 1.0 

3/29/2005 8.5 1487.5 39.1 3,902,013 18,928 3,318,566 5220 14.0 14.0 0.0 

3/30/2005 9.6 1497.1 41.6 3,922,384 20,371 3,338,937 5252 16.0 16.0 0.0 

25 3/31/2005 8.9 1506.0 39.9 3,941,732 19,348 3,358,285 5282 16.0 16.0 0.0 

4/1/2005 8.5 1514.5 40.7 3,960,622 18,890 3,377,175 5312 16.0 16.0 0.0 

4/2/2005 9.8 1524.3 42.3 3,982,195 21,573 3,398,748 5346 15.0 15.0 0.0 

4/3/2005 9.8 1534.1 43.9 4,003,448 21,253 3,420,001 5379 14.0 13.0 1.0 

4/4/2005 8.7 1542.8 40.6 4,022,552 19,104 3,439,105 5409 14.0 13.0 1.0 

4/5/2005 7.7 1550.5 42.5 4,038,787 16,235 3,455,340 5435 16.0 10.0 6.0 

4/6/2005 8.0 1558.5 44.4 4,056,802 18,015 3,473,355 5463 16.0 10.0 6.0 

26 4/7/2005 7.8 1566.3 38.7 4,074,577 17,775 3,491,130 5491 11.0 11.0 0.0 

4/8/2005 8.5 1574.8 39.6 4,093,908 19,331 3,510,461 5521 14.0 10.0 4.0 

4/9/2005 9.1 1583.9 42.5 4,113,962 20,054 3,530,515 5553 16.0 10.0 6.0 

4/10/2005 10.2 1594.1 42.5 4,135,968 22,006 3,552,521 5587 15.0 10.0 5.0 

4/11/2005 9.2 1603.3 44.6 4,155,862 19,894 3,572,415 5619 16.0 10.0 6.0 

4/12/2005 10.2 1613.5 42.4 4,178,409 22,547 3,594,962 5654 15.0 15.0 0.0 

4/13/2005 7.5 1621.0 47.3 4,195,027 16,618 3,611,580 5680 16.0 16.0 0.0 

27 4/14/2005 8.8 1629.8 41.4 4,214,799 19,772 3,631,352 5711 15.0 14.0 1.0 

4/15/2005 9.4 1639.2 10.6 4,235,652 20,853 3,652,205 5744 13.0 13.0 0.0 

4/16/2005 10.6 1649.8 39.3 4,258,123 22,471 3,674,676 5780 13.0 13.0 0.0 

4/17/2005 10.8 1660.6 45.4 4,280,778 22,655 3,697,331 5815 14.0 13.0 1.0 

4/18/2005 9.6 1670.2 44.7 4,300,836 20,058 3,717,389 5847 15.0 15.0 0.0 

4/19/2005 10.0 1680.2 40.9 4,321,862 21,026 3,738,415 5880 16.0 15.0 1.0 

4/20/2005 10.2 1690.4 41.9 4,343,599 21,737 3,760,152 5914 15.0 15.0 0.0 

28 4/21/2005 9.0 1699.4 44.6 4,363,147 19,548 3,779,700 5945 16.0 15.0 1.0 

4/22/2005 24.7 1724.1 27.4 4,405,545 42,398 3,822,098 6011 8.0 7.0 1.0 

4/23/2005 7.8 1731.9 44.1 4,422,047 16,502 3,838,600 6037 13.0 13.0 0.0 

4/24/2005 9.0 1740.9 41.5 4,440,999 18,952 3,857,552 6067 14.0 13.0 1.0 

NM = Not Measured

NA = Not Available
APPENDIX B 

ANALYTICAL RESULTS
Analytical Results 

B-1 

Sampling Date 10/13/04(c)(d) 10/19/04 10/26/04 

Sampling Location 

Parameter Unit 

IN AP TA TB IN AP TA TB IN AP TA TB I

Bed Volume 103 − − 0 − − 0.2 − − 0.4 

Alkalinity mg/L(a) 55 55 57 59 61 41 55 55 57 43 45 46 

Fluoride mg/L 0.7 0.7 1.1 0.8 − − − − − − − − 

NO3-N mg/L 1.0 0.5 1.3 1.4 − − − − − − − − 

Orthophosphate mg/L(b) <0.06 <0.06 <0.06 <0.06 <0.06 <0.06 <0.06 <0.06 <0.06 <0.06 <0.06 <0.06 <

Silica (as SiO2) mg/L 18.8 19.1 50.8 61.8 19.4 19.8 39.1 54.2 19.5 19.4 28.5 36.8 

Sulfate mg/L 24.0 26.0 12.0 9.6 − − − − − − − − 

Turbidity NTU 0.7 0.1 0.2 0.2 0.7 0.5 0.4 0.5 0.4 0.2 <0.1 <0.1 

pH S.U. 7.8 7.8 7.9 8.0 6.8 6.8 7.0 7.1 7.1 6.9 7.1 6.9 

Temperature oC 12.3 12.7 12.9 13.0 11.7 11.7 11.7 11.8 12.1 11.9 11.8 11.7 

DO mg/L 5.5 2.9 4.1 4.0 5.8 3.6 3.8 4.3 5.5 3.9 3.6 4.5 

ORP mV 198 190 183 173 234 233 227 231 NA(e) NA(e) NA(e) NA(e) 2

Free Chlorine mg/L − 0.2 0.1 0.1 − 0.7 0.3 0.6 − 0.1 0.2 0.1 Total Chlorine mg/L − 0.1 0.1 0.1 − 0.4 0.3 0.5 − 0.1 0.2 0.1 

Total Hardness mg/L(a) 163.3 128.4 166.6 86.8 − − − − − − − − 

Ca Hardness mg/L(a) 125.5 99.1 122.2 41.4 − − − − − − − − Mg Hardness mg/L(a) 37.8 29.3 44.4 45.4 − − − − − − − − 

As (total) μg/L 91.3/ 89.5 96.1/ 90.2 37.5/ 34.4 17.1/ 16.7 49.8 50.7 30.7 21.8 52.0 52.2 14.5 5.4 As (total soluble) μg/L 50.5/ 46.9 52.3/ 47.8 25.3/ 23.3 14.3/ 14.6 − − − − − − − − 

As (particulate) μg/L 40.8/ 42.6 43.8/ 42.4 12.2/ 11.1 2.8/ 2.1 − − − − − − − − 

As (III) μg/L 0.7 0.6 0.8 1.1 − − − − − − − − 

As (V) μg/L 49.8/ 46.2 51.7/ 47.2 24.5/ 22.5 13.2/ 13.5 − − − − − − − − 

Total Fe μg/L <25/ <25 60/ 56 <25 39/ 38 <25 <25 <25 <25 <25 <25 <25 <25 <

Dissolved Fe μg/L <25 <25 <25 <25 − − − − − − − − 

Total Mn μg/L 1.8/ 1.2 7.2/ 4.6 19.3/ 19.1 5.1/ 6.0 0.8 0.4 12.0 7.1 0.5 0.8 27.0 31.5 

Dissolved Mn μg/L 0.4/ 0.6 0.3/ 0.5 9.0/ 10.4 4.1/ 4.9 − − − − − − − − 

(a) as CaCO3. (b) as PO4. (c) (/) indicates re-run data with original result/re-run result. (d) System start-up on October 13, 2004. H2SO4 acid addition not yet operationa

properly. IN = inlet; AP = after pH adjustment and after pre-chlorination; TA = after Vessel A; TB = after Vessel B; TT = after vessels combined. NA = data not availab
Analytical Results 

B-2 

Sampling Date 11/16/04(c) 11/30/04 12/14/04(d) 

Sampling Location 

Parameter Unit 

IN AP TA TB IN AP TA TB IN AP TA TB I

Bed Volume 103 − 1.0 − − 1.5 − − 1.9 

Alkalinity mg/L(a) 254 46 43 45 61 41 41 41 67 31 31 31 6

6

Fluoride mg/L − − − − − − − − 1.1 1.0 0.8 0.7 NO3-N mg/L − − − − − − − − 0.2 0.1 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 <0.06 <0.06 <0.06 <

<

Silica (as SiO2) mg/L 18.9 19.5 26.4 33.0 19.4 19.6 24.8 30.9 19.2 19.4 25.0 28.4 2

2

Sulfate mg/L − − − − − − − − 11.0/ 11.1 39.0/ 46.7 39.0/ 45.7 39.0/ 46.6 

Turbidity NTU 0.3 0.4 0.3 0.3 1.1 0.3 0.1 0.4 0.5 0.2 0.3 0.4 

pH S.U. 7.4 6.9 6.8 6.8 7.4 6.7 6.7 6.7 7.4 6.5 6.4 6.4 

Temperature oC 11.9 11.8 11.7 11.5 11.8 11.9 11.7 11.5 11.5 11.6 11.5 11.5 1

DO mg/L 5.7 4.4 4.5 4.4 4.7 4.7 4.7 4.7 5.6 4.6 4.4 4.5 

ORP mV 218 219 221 222 208 524 542 450 211 548 554 553 49

Free Chlorine mg/L − 0.1 0.1 0.1 − 0.2 0.1 0.1 − 0.2 0.1 0.1 

Total Chlorine mg/L − 0.1 0.1 0.1 − 0.2 0.2 0.1 − 0.2 0.1 0.1 

Total Hardness mg/L(a) − − − − − − − − 92.1 98.7 93.5 101.8 

Ca Hardness mg/L(a) − − − − − − − − 72.3 77.5 72.6 79.2 

Mg Hardness mg/L(a) − − − − − − − − 19.8 21.2 20.9 22.6 

As (total) μg/L 44.2 44.9 14.2 3.8 42.4 43.5 13.5 3.3 52.3 55.2 15.6 50.9/ 50.8 3

3

As (total soluble) μg/L − − − − − − − − 52.6 55.7 15.5 3.6 

As (particulate) μg/L − − − − − − − − <0.1 <0.1 0.1 47.3 

As (III) μg/L − − − − − − − − 0.6 0.6 0.7 0.6 

As (V) μg/L − − − − − − − − 52.0 55.1 14.8 3.0 

Total Fe μg/L <25 <25 <25 <25 <25 <25 <25 <25 <25 <25 <25 <25/ <25 <2

<2

Dissolved Fe μg/L − − − − − − − − <25 <25 <25 <25 Total Mn μg/L 0.2 <0.1 12.5 28.3 0.7 0.5 5.2 15.3 1.2 0.6 5.0 13.3/ 12.8 

Dissolved Mn μg/L − − − − − − − − 0.4 0.4 4.8 12.5 

(a) as CaCO3. (b) as PO4. (c) Began bi-weekly sampling instead of weekly sampling. (d) (/) indicates re-run data with original result/re-rerun result. (e) Duplicate samp

IN = inlet; AP = after pH adjustment and after pre-chlorination; TA = after Vessel A; TB = after Vessel B; TT = after vessels combined, NA = data not available. 
Analytical Results 

B-3 

Sampling Date 01/18/05 02/01/05 02/15/05 

Sampling Location 

Parameter Unit 

IN AP TA TB IN AP TA TB IN AP TA TB I

Bed Volume 103 − − 2.6 − − 3.4 − − 3.8 

Alkalinity mg/L(a) 66 35 33 35 69 43 37 41 69 45 36 38 120 

Fluoride mg/L − − − − 0.9 1.0 0.7 0.3 − − − − 

NO3-N mg/L − − − − 0.22 0.19 0.23 0.24 − − − − 

Orthophosphate mg/L(b) 0.3 0.2 <0.05 <0.05 0.1 0.06 <0.05 <0.05 <0.05 0.05 <0.05 <0.05 <0.

Silica (as SiO2) mg/L 19.7 20.1 22.7 25.3 18.7 18.5 21.1 24.9 20.0 20.1 22.9 24.9 19.

Sulfate mg/L − − − − 11.0 47.0 48.0 48.0 − − − − 

Turbidity NTU 0.5 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.pH S.U. 7.5 6.5 6.4 6.4 7.4 6.5 6.4 6.5 7.4 6.5 6.3 6.3 

Temperature oC 12.4 12.6 12.3 12.3 11.5 11.6 11.4 11.2 11.5 11.5 11.5 11.2 1

DO mg/L 6.0 4.5 4.0 3.9 6.6 5.6 5.3 5.4 NA(c) NA(c) NA(c) NA(c) 

ORP mV 238 207 548 584 211 587 591 586 212 580 594 595 19

Free Chlorine mg/L − 0.3 0.2 0.2 − 0.2 0.2 0.2 − 0.3 0.3 0.2 Total Chlorine mg/L − 0.3 0.3 0.2 − 0.2 0.2 0.2 − 0.3 0.2 0.2 

Total Hardness mg/L(a) − − − − 84.0 81.5 85.0 89.6 − − − − 

Ca Hardness mg/L(a) − − − − 65.9 64.0 66.6 70.0 − − − − Mg Hardness mg/L(a) − − − − 18.1 17.5 18.4 19.6 − − − − 

As (total) μg/L 46.1 46.3 15.1 2.1 54.1 54.5 24.4 5.0 45.5 46.1 17.2 3.3 4

As (total soluble) μg/L − − − − 54.6 54.4 24.8 5.0 − − − − 

As (particulate) μg/L − − − − <0.1 0.1 <0.1 <0.1 − − − − 

As (III) μg/L − − − − 0.5 0.5 0.4 0.4 − − − − 

As (V) μg/L − − − − 54.1 53.9 24.4 4.6 − − − − 

Total Fe μg/L <25 <25 <25 <25 <25 <25 <25 <25 <25 <25 <25 <25 <2

Dissolved Fe μg/L − − − − <25 <25 <25 <25 − − − − 

Total Mn μg/L 0.6 0.8 3.0 2.8 0.5 3.3 1.1 1.5 0.7 0.7 1.4 2.4 Dissolved Mn μg/L − − − − 0.5 0.5 1.2 1.3 − − − − 

(a) as CaCO3. (b) as PO4. (c) DO probe not working properly.

IN = inlet; AP = after pH adjustment and after pre-chlorination; TA = after Vessel A; TB = after Vessel B; TT = after vessels combined; NA = data not available.
Analytical Results 

B-4 

Sampling Date 03/15/05 03/29/05(d) 04/12/05 

Sampling Location 

Parameter Unit 

IN AP TA TB IN AP TA TB IN AP TA 

Bed Volume 103 − − 4.8 − − 5.2 − − 

Alkalinity mg/L(a) 77 69 35 39 37 37 38 37 66 33 29 28 67 28 44 

Fluoride mg/L − − − − 0.9 1.0 0.9 0.8 − − − 

NO3-N mg/L − − − − 0.2 0.2 0.2 0.3 − − − 

Orthophosphate mg/L(b) <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.0

Silica (as SiO2) mg/L 21.4 20.3 21.4 20.8 23.9 22.7 24.4 24.3 19.8 19.7 21.4 23.5 20.7 20.1 23.0 

Sulfate mg/L − − − − 11.0 51.0 48.0 46.0 − − − 

Turbidity NTU <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 0.3 <0.1 0.1 <0.

pH S.U. 7.4 6.6 6.3 6.3 7.4 6.1 6.1 6.1 7.3 6.1 6.4 

Temperature oC 11.9 11.9 11.7 11.6 11.7 11.5 11.4 11.4 11.7 11.6 11.7 

DO mg/L NA(c) NA(c) NA(c) NA(c) 5.3 4.3 4.7 4.4 4.8 3.9 4.8 

ORP mV 213 608 606 608 212 577 590 594 192 560 577 

Free Chlorine mg/L − 0.5 0.3 0.4 − 0.4 0.4 0.3 − 0.4 0.3 Total Chlorine mg/L − 0.5 0.4 0.4 − 0.4 0.3 0.3 − 0.3 0.4 Total Hardness mg/L(a) − − − − 95.4 93.4 101.4 98.5 − − − 

Ca Hardness mg/L(a) − − − − 75.8 72.7 77.2 75.7 − − − Mg Hardness mg/L(a) − − − − 19.6 20.7 24.2 22.8 − − − 

As (total) μg/L 48.1 47.8 46.9 47.0 23.0 23.1 6.9 6.8 48.9 50.0 21.0 5.5 42.8 41.5 26.3 

As (total soluble) μg/L − − − − 48.2 49.7 20.8 5.5 − − − 

As (particulate) μg/L − − − − 0.7 0.3 0.2 <0.1 − − − 

As (III) μg/L − − − − 0.7 0.6 0.6 0.7 − − − 

As (V) μg/L − − − − 47.5 49.1 20.2 4.8 − − − 

Total Fe μg/L <25 <25 <25 <25 <25 <25 <25 <25 <25 <25 <25 <25 <25 <25 <25 

Dissolved Fe μg/L − − − − <25 <25 <25 <25 − − − 

Total Mn μg/L 2.0 1.9 1.9 1.8 0.6 0.5 0.3 0.3 1.2 0.9 1.2 1.5 0.1 0.1 0.5 

Dissolved Mn μg/L − − − − 1.2 1.0 1.4 1.4 − − − 

(a) as CaCO3. (b) as PO4. (c) DO probe not working properly. (d) On-site water quality parameters measured on March 28, 2005.

IN = inlet; AP = after pH adjustment and after pre-chlorination; TA = after Vessel A; TB = after Vessel B; TT = after vessels combined; NA = data no