Evaluating Arsenic

Treatment Providers

An iron-based adsorptive media arsenic removal system in Rimrock, Arizona.

A Guide for Public Water Systems
Printed on Recycled Paper
The SDWA provisions and EPA regulations described in this document

contain legally binding requirements. This document does not substitute for

those provisions or regulations, nor is it a regulation itself. Thus, it does not

impose legally binding requirements on EPA, States, Tribes or the regulated

community, and may not apply to a particular situation based upon the

circumstances. EPA, State, and Tribal decision makers retain the discretion to

adopt approaches on a case-by-case basis that differ from this guidance

where appropriate. Any decisions regarding a particular facility will be made

based on the applicable statutes and regulations. Therefore, interested parties

are free to raise questions and objections about the appropriateness of the

application of this guidance to a particular situation, and EPA will consider

whether or not the recommendations or interpretations in the guidance are

appropriate in that situation. EPA may change this guidance in the future.

1

Introduction oductionOn January 22, 2001 EPA revised the arsenic standard to 10 parts per billion (ppb). All publicwater systems must comply with this 10 ppb maximum contaminant level (MCL) by January23, 2006. Some systems will have to install treatment for arsenic removal in order to meetthe revised MCL. For more compliance information, please visit http://www.epa.gov/safewater/arsenic.There are a number of technologies to choose from, and numerous engineering firms andtreatment vendors who can help you with treatment selection, installation, and operation.Choosing the right technology and firm for your system can be a confusing and timeconsuming process. The information in this brochure will help you navigate through theprocess of selecting the most appropriate treatment for your systemThis guide will provide you with: An overview on the long-term, chronic health effects linked to drinking water that contains

arsenic.

 Basic information on available treatment technologies for arsenic removal. Important questions to ask engineering firms and vendors when looking for the best

treatment for your system and the best firm to design and install the technology.

 Information on estimating treatment installation and operation costs and sources of

additional information on arsenic and arsenic removal.

By working through the handouts in this brochure and by reading the questions and answers,you will be able to more confidently choose an engineer or a vendor that you trust to help youmake the best choices for your system.

removal system.
2

Health Ef Health Ef Health Effects & Risk Communication ects & Risk CommunicationThe revised arsenic standard will protect consumers against these effects of long-term,chronic exposure to arsenic in drinking water. Long-term exposure to arsenic has been linkedto bladder, lung, skin, kidney, nasal passage, liver, and kidney cancer. Ingesting arsenicthrough drinking water may also cause cardiovascular, pulmonary, immunological,neurological, and endocrine problems (e.g., diabetes). Short-term exposure to high doses(greater than 50 parts per billion) of arsenic can have other negative health effects.If you will be making a significant investment in treatment or non-treatment options to removearsenic from your drinking water, it is important that you inform your customers of why you aremaking this investment and how it will benefit them now and in the future.Information f ormation f ormation for Vendors & Engineer s & Engineer s & EngineersTo navigate through the increasingly complex and confusing arena of options available for youto remove arsenic from your drinking water, you will have to work with an engineer or anequipment vendor. Before you initiate contact, you will need to gather basic information oneach water source that needs to be treated. Fill out the handout on the following page.Systems with multiple sources should photocopy the form and fill it out for each water source.For information on current treatment capacity, review historical records to determine youraverage and maximum flow rates. If you are using wells, it is important to know the flowthroughout the pumping cycle as it will change with differing system pressures. If records arenot available, conduct flow monitoring prior to entering into any agreement with a vendor orobligating the water system to any specific treatment technology.You will also need information on the treatment currently in place at your system. If you arealready chlorinating the water, you could be converting the arsenic to a treatable form (i.e., toarsenate). If you are conducting iron or manganese removal, you may already be removingarsenic and it may be possible to optimize your system (rather than installing new treatment)to remove enough arsenic to meet the revised MCL.

 the following

n hand for

who you could

k with.
3

Water Syst er System Information Summar ormation Summary Form

Contact Information

Phone Number

E-mail

Address

Site Location Parameters

l, etc.)

e, in GPM)

GPM)

Disinfection, Storage, and Discharge

si)

y, hydropneumatic), and Location

wer, evaporation pond, etc.)

able to produce enough water to meet the system's maximum daily demand (i.e., the maximum amount of water used by the system over a 24-hour
4

Water Syst er System Information Summar ormation Summary Form (continued) orm (continued) orm (continued)

Source Water Parameters (enter all known averages)

Antimony mg/L

m m g/L Chromiu mg/L

m d g/L Lea mg/L

m m g/L Molybdenu mg/L

L m m g/ Seleniu mg/L

m s g/L Suspended Solid mg/L

m n g/L Iro mg/L

m m g/L Vanadiu mg/L

m s g/L Dissolved Solid mg/L

m y g/L Turbidit NTU

mg/L
5

Treatment T reatment T reatment Technology Brief hnology Brief hnology Briefs

ns Brief Description Considerations

The installation or procurement of a new low arsenic

source of supply.

S . imple

Most realistic with multiple water sources where at least one source can

be relied upon to produce water with arsenic below the MCL.

Constraints include inadequate capacity or water rights.

System switches high arsenic source to seasonal or

peaking use only.

Not an option for systems with only one source.

State requirements may preclude this option.

Operating low arsenic source in conjunction with the high

arsenic sources.

Must have more than one source.

Wells with low arsenic levels must be continuously reliable and have a

common header to allow for mixing with high arsenic source water.

These brief descriptions of the available treatment and non-treatment options provide anoverview of process characteristics as well as key considerations for selecting the option. Theyare designed to function as a basic reference for beginners and a quick guide to supplementadditional investigation.

s Brief Description Considerations

Iron-based granular materials are placed in a pressure

vessel and water is passed through the vessel. Dissolved

As(V) is adsorbed onto the iron medium. After the

medium is exhausted, it must be disposed of and replaced.

Optimal performance is obtained at lower pH values.

Recommend an empty bed contact time (EBCT) of 5 minutes and a

hydraulic loading rate of 5 gpm/sft.

Phosphate and silica have been shown to compete aggressively with

As(V) for adsorption sites.

Has not exceeded Resource Conservation and Recovery Act (RCRA)

toxicity characteristics.

AA is a sorption process that uses porous, aluminumbased granular material with ion exchange properties. Effected by constituent(s) interference with adsorption process, selectivity sequence, preoxidation of As(III) to As(V), and presence of

suspended solids.

Capacity for removal is pH dependent with best removal occurring

between the pH of 5 and 6.

Will produce liquid and solid waste (if using a throw-away media)
6

Treatment T reatment Technology Brief hnology Briefs (continued) s (continued) s (continued)

n Brief Description Considerations

A physical-chemical process in which ions are swapped

between a solution phase and solid resin phase. After the

resin becomes exhausted, it can be regenerated with a

brine solution.

 Efficiency depends on the concentration of other anions, most notably

sulfates and nitrates.

 High levels of total dissolved solids (TDS) can adversely affect the

performance of an IX system.

Pre-filtration is recommended if the source water turbidity exceeds 0.3

NTU.

Chromatographic peaking and resin fouling may occur.

Spent regenerant may need to be treated before disposal.

Spent IX resins tend not to exceed regulatory toxicity concentrations.

A precipitative process using coagulants including

aluminum and ferric salts, which hydrolyze to form

aluminum and iron hydroxide particulates, respectively.

As(V) is adsorbed onto the metal hydroxide floc particles

and is removed by filtration (either be granular media or

membranes).

Efficiency is contingent upon the type and dosage of coagulant, mixing

intensity, and pH.

R . emoval performance of aluminum-based coagulants drops at pH > 7

Pre-oxidation is typically necessary.

Realistic possibility for new installations.

(CMF) Realistic possibility for new installations.

Filter membrane must be periodically backwashed to dislodge solids

and restore hydraulic capacity.

Reject water is generally high in TDS.

A precipitative process involving the oxidation of soluble

iron to insoluble forms and then removal by filtration.

Removal efficiency is strongly dependent on the initial iron and arsenic

concentrations.

Fe:As mass ratio should be at least 20:1, which assumes 1 mg/Fe

removes 50 ug/As.

Arsenic removals decrease with increasing pH.

High levels of natural organic matter (NOM), orthophosophates, and

silicates lessen efficiency.

Greensand media must be regenerated with permanganate or chlorine.

try (POE) POU treatment units treat the water at a single faucet.

POE treatment devices treat all of the water coming into a

building.

Must be owned, controlled, and maintained by the utility or by an

agency under contract with the utility.

Reduces capital costs but increases administrative and monitoring costs.

Economically viable alternative to centralized treatment for systems

serving roughly 50-500 people.

State requirements may preclude this option.

eatment technologies can be found at www.arsenictradeshow.com.
7

Information fr ormation fr ormation from Engineer om Engineer om EngineersYou can gather a good deal of information from prospective engineering firms by giving themthe handout that follows. It will provide you with a summary of the firm’s and its staff’sexperience with installing arsenic technologies at systems like yours, and contact informationfrom these systems. Review the engineering firm’s experience and contact its references andformer clients to see whether the firm is a good fit for your system. Include your contactinformation in the designated spot at the bottom of the form.

Have prospective engineering firmsfill out the handout on the following

page and use it to review the each

firm’s experience and contact its

references.
8

Engineering Firm Inf Engineering Firm Information Summar ormation Summary

Key Contact Name

Key Contant E-mail

Key Contact Phone

Relevant Past Experience

se describe your firm's experience with installing or modifying arsenic treatment technologies, including the systems at which the treatment

t, and a description of the treatment unit.

) 

Contact Info (Name/Phone System Size (pop., service connections, design

flow)

Describe Treatment Installed (including dates of

installation)

Staff Experience

e list the qualifications and experience of staff members familiar with all aspects of arsenic treatment technology installation and operation.

l 

P ) hone/E-mai Q e ualifications/License(s Describe Relevant Experienc
9

Selecting an Engineering Firm Selecting an Engineering Firm

If you hire an engineer to help design and install the treatment, consider the followingquestions when contacting prospective engineering firms and when working with theengineers to choose the most appropriate treatment technology. If the engineer cannotanswer these questions, he or she should work with the vendor to get you the information youneed to make informed decisions.

estions

ogy affect

understanding

 future

ations that

nt affect

er Rules?

treatment

ated into the

ture?

Background Inf ound Information ormation

Questions Reason for Question or What to Look for in the Answer

Are you a registered Professional

Engineer in this state?

Some states require that a licensed professional engineer create any plans and

specifications for system construction or modification.

What experience do you have

designing treatment facilities and

arsenic removal technologies for small

public water systems? Can you

provide references?

Hiring an experienced engineer provides a certain level of comfort. If the

engineer has little or no relevant experience, determine how they will overcome

that obstacle. Talking with another system about their experiences with the

engineer can also be extremely valuable.

What kinds of treatment facilities

have you designed? Can you provide

references?

An engineer with a broad base of knowledge can better assist you in choosing

the best technology for your system. This person should also be familiar with

the State's permitting process.

How much experience have you had

getting water treatment facilities

approved in our state? Can you

provide references?

Design is the first step; getting the state to approve the design is the next hurdle.

You want an engineer who is familiar with the often lengthy approval process.

Who in your firm is best qualified in

the area of arsenic removal

technologies?

An engineering firm is only as good as the person(s) that will actually be doing

the work. Get a commitment on the names and qualifications of the staff that

will be working for you, and the amount of time that they can devote to your

project.
10

Working with V king with Vendors

Questions Reason for Question or What to Look for in the Answer

How do you deal with vendors that

provide proprietary technologies?

You want an engineer that protects your interest by evaluating all technologies

carefully, and not just relying on the vendors' recommendations or past experience

with a single technology.

Have you worked with specific

vendors in the past?

Call former clients to learn how the engineer has dealt with vendors in the past.

How do you ensure the success of a

proprietary technology?

Ask the engineer for a protocol they have used before in evaluating treatment

technologies (e.g., pilot testing, bench scale evaluations, etc.).

Funding

Questions Reason for Question or What to Look for in the Answer

Are there sources of funding

available to help cover the costs of

treatment, and do you have

experience helping systems obtain

funding?

The engineer should be able to offer assistance and advice in this area. You can

also contact your primacy agency to find out what funding your system is eligible

for or see http://www.epa.gov/safewater/arsenic for information on the Drinking

Water State Revolving Loan Fund and other funding sources.

Ask if raising rates and self-funding is a better option. The engineer may be able

to offer valuable advice and guidance on the process of obtaining funds.

 for ion exchange
11

Water Quality and Current F er Quality and Current Facilities acilities

Reason for Question or What to Look for in the Answer

Most technologies will remove other constituents besides arsenic. This can positively

or negatively affect treated water quality. You may be able to select a technology

that will resolve other problems (e.g., remove both iron and arsenic), but you should

also be aware of the potential "side effects" of the technology.

Providing these services will be a major expense-be aware of all the additional costs

associated with treatment installation.

You may need numerous permits to construct the building, each of which has their

own set of requirements. Make sure that your engineer will develop a schedule for

obtaining the necessary permits.

You will need to know the regulatory requirements and discuss all compliance

options with the engineer. You may even want to consider purchasing treated water

from, or consolidating with, another system. Your engineer should be able to help

you address these issues.

You must know if you have to use the well all the time or only during periods of high

use. Also, you need to know if intermittent operation can cause problems. Your

engineer should be able to answer these questions.

ology Impact and Monit ology Impact and Monitoring

Reason for Question or What to Look for in the Answer

gineer should know what water quality monitoring is necessary for process selection

gn. Get a list of parameters and frequency of the testing that needs to be done, and

st estimate from the engineer. Make sure you understand the time required to get

e monitoring data, and factor it into your compliance time-line.

e to know the operational requirement, both in terms of time and expertise, in order to

e costs. Have the engineer estimate the level of operator attention the treatment plant

uire and make sure the estimation is approved by the state. Some treatment

gies are more expensive to install but require less time to operate. Have your engineer

various levels of automation.
12

Impact on Water Quality and Current F er Quality and Current Facilities (cont.) acilities (cont.) acilities (cont.)

Questions Reason for Question or What to Look for in the Answer

Will we be able to add additional

capacity or treatment processes

at the new facility at a later

date?

You need to have the ability to provide additional capacity to the system if there is a

potential to expand your water system. Understand the growth potential of your

system and consider installation of treatment technology that will meet that need, or

phased construction that will provide for future growth.

Will we have pressure and

capacity through the new facility

that will have to be compensated

for with pump change-out?

Almost all treatment processes will have pressure losses through the treatment plant.

Your engineer must determine what the losses might be, and how you can minimize

them. If the headlosses are high enough to cause a significant loss of flow, or

pumping efficiency, your engineer should consider changing out, or modifying, the

pump.

Will we have water losses

through the new facility that will

have to be compensated for by

additional wells?

You will need to understand the production losses of each of the treatment

technologies you consider. In many cases, the water loss can be reduced

significantly (e.g., recycle of backwash water). In all cases, you must ensure the

production is adequate to meet your maximum day demand.

Are there increased process

monitoring sampling requirements

for the treatment process?

For proper operation, the treatment system will require some process monitoring that

is in addition to the regulatory sampling. The specific process control monitoring

requirements may be system-specific, and will be established by your primacy

agency. Be sure you understand what those requirements are. Ask the engineer to

identify sampling sites and testing methods and explain State requirements. There are

less expensive methods for process monitoring than for regulatory monitoringunderstand the difference between them.

val.
13

Information fr ormation fr ormation from VendorsYou can gather a good deal of information from prospective vendors by giving them thehandout that follows. It will provide you with a summary of the firm’s and its staff’s experienceand the types of treatment technology it offers. Review their experience and contact theirreferences and former clients to see whether they and the technologies they provide are agood fit for your system. Include your contact information in the designated spot at the bottomof the form.

Have prospective vendors fill out the

handout on the following page and

use it to review the each firm’s

experience and the types of treatment

technology it offers.
14

Vendor Inf endor Information F ormation Form

Key Contact Name

Key Contant E-mail

Key Contact Phone

Arsenic Treatment Technologies

e arsenic treatment technologies that your firm provides. List NSF certifications, expertise required to operate the unit, and the type of

n 

N d SF Certificatio O d perator Expertise Require Residuals Generate

Units Currently in Place

les of arsenic treatment units that you have installed, if any. Briefly describe the type and size of the unit and the size and type of system at

se also provide system contact information.

) 

Contact Info (Name/Phone System Size (pop., service connections, design

flow)

Describe Treatment Installed (including dates of

installation)

tallation?

nd technical assistance?

ntract?
15

Selecting a V Selecting a Vendor

There are several approaches to working with vendors. If you hire an engineer, he or she maybe the one contacting, selecting, and working with the vendor. Some water systems choose towork with vendors directly (make sure this is an acceptable practice in your state), becausesome vendors will provide a package that includes the design and installation of a treatmentsystem. When contacting and selecting a vendor, you and your engineer should keep in mindthe questions listed below.

General Inf General Information on T ormation on Technology hnology

Questions Reason for Question or What to Look for in the Answer

Do you have installations in

place for arsenic removal? Can

you provide details on the

treatment and contact

information for these systems?

It is critical that you determine the vendor's experience in arsenic drinking water

treatment. Ask system operators about their experience with the vendor's equipment

including, treatment efficiency, water quality issues, water loss, customer assistance,

guarantees, and ease of operation.

What are the technology's water

quality limitations?

Some raw water constituents can limit treatment run times, media life, and costs.

Reputable vendors should be able to tell you what constituents challenge their

technology.

What level of treatment can the

technology achieve?

You need to ensure that the technology will enable you to meet the arsenic MCL

given your water quality and system characteristics.

Are coatings and contact surfaces

NSF certified? Can I see the

certification?

All components should have NSF Standard 61 certifications. If you are

contemplating use of POU devices, ask the vendor if the unit has NSF Standard 53

or 58 certification. (Also check the NSF Web site for their listing:

http://www.nsf.org/business/drinking_water_systems_center/index)

For adsorptive media: Is the

medium NSF certified? Can I

see the certification?

Drinking water system components must have NSF Standard 61 certification.

What are the typical design

criteria for your technology

(Empty Bed Contact Time

[EBCT] and surface loading

rate)?

Many proprietary systems have specific design criteria to ensure the technology

works. Your final design will have to meet those criteria in order to get the vendor

to accept responsibility for ensuring compliance. EBCT, for example, determines the

size of the treatment vessels needed (which determines the building size). For

coagulation/filtration plants, the same is true of the surface loading rates on the filters.

Make sure that the information provided meets state design standards.
16

Questions Reason for Question or What to Look for in the Answer

What chemicals will I have to add? What

is their cost and availability? Do they

require special handling? Are they all

NSF certified?

Each treatment technology is somewhat different. With some, you may have

to add certain chemicals to adjust pH, oxidize the raw water, or regenerate

the media. You need to know what chemicals, if any, will be needed; their

costs, availability and handling/safety requirements. Any chemical that is

added to the drinking water must have NSF 60 certification.

What waste streams does the technology

produce and what is the approximate

quantity of the wastes?

The wastes produced by the technology can sometimes be very difficult to

handle and dispose of. This information could be a major determining factor

in your treatment selection. You should be sure that you have a means

through which to dispose of the waste.

Would the waste streams be characterized

as hazardous?

Though most of the waste streams will not be hazardous, ask for certification

that the waste will pass the Toxicity Characteristic Leaching Procedure test

(or Waste Extraction Test, for systems in California). Have the vendor

identify any contaminants that treatment will remove that may cause the waste

to be characterized as hazardous. Disposal of hazardous waste is more

difficult and costly.

What is the typical range of water loss (in

percent of total raw water flow) when

using your technology? Identify each

point where water loss occurs and

indicate what operating conditions

increase water losses.

All treatment systems produce some water loss. Determine the degree of

water loss and consider this information when choosing a technology.

What is the size of the system's footprint

and the required building height and

square footage?

The building needed to house the treatment plant can be a considerable

expense. This is particularly important if space and land availability are at a

premium in your location.

Do I have to provide pretreatment? If so,

what type? Can the pretreatment cause

any water quality or operational

problems?

You need to know all treatment requirements at the outset. Pretreatment is

typically required to oxidize the arsenic to a more treatable form. Sometimes

filtration is required to minimize media fouling. Also ask your state for their

pretreatment requirements.

Does the technology remove arsenic (III)

and arsenic (V)? Can it remove both

with equal efficiency?

Arsenic (III) is not efficiently removed by most treatment technologies. If the

vendor contends that the technology will remove both species of arsenic

efficiently, ask for long-term documentation.

If the system is a custom unit (i.e., the

media and equipment are purchased from

two different suppliers) who do you

consider responsible for making the

system work?

Custom designing a system can be a liability nightmare if the treatment

technology does not work. Identify the criteria that must be met by each

party and have performance testing as a part of full payment.

Do you have a local representative who

can provide timely assistances?

There is nothing better than having local service. The vendor needs to be

available to provide technical assistance in a timely manner.

General Inf General Information on T ormation on Technology (cont.) hnology (cont.) hnology (cont.)

ange system.
17

Costs

Reason for Question or What to Look for in the Answer

Replacing and disposing of media can be very expensive. Find out if the vendor will

dispose of the spent media and get an estimate of the associated costs. Ask for a full

disclosure of capital and operation and maintenance costs including testing for

hazardous waste characteristics.

Guarantees are only as good as the company that provides them. Ask for

performance bonds for unit processes and establish performance testing Ask for a

life expectancy of media, replacement costs, and disposal. Make sure that the

finished water quality meets state and federal requirements and that the performance

bond ensures that you will be able to meet those lets.

Some vendors will let you lease the equipment with a discounted purchase price at

the end of the lease. Make sure that you have the legal right to lease equipment.In some cases, installation costs will be almost as much as the capital equipment

costs. You need to know this prior to purchasing the technology.

Start-up

Reason for Question or What to Look for in the Answer

Some media needs to be conditioned on-site; ask whether this is part of the initial

media cost. Some conditioning processes require large volumes of water, which

have to be disposed of.

You should know how the equipment will be delivered and what to do if

equipment arrives damaged. Inspect the equipment thoroughly when it is

delivered. Do not accept damaged equipment or agree to have damaged

equipment repaired until you have decided who is responsible for the repair cost.

Knowing who will install the system and ensuring that they have the proper training

and experience is important. Having technical assistance during start-up is very

important. Build a start-up plan into the purchase agreement that identifies a

schedule, amount of assistance provided, and availability for assistance after startup.

Many vendors will provide extended agreements beyond the typical warranty

period.
18

Operations Operations

Reason for Question or What to Look for in the

Answer

What

Get a detailed description of how the system operates and a list of

existing plants in operation that you can contact for more

information.

Will I

ring

? How

Some treatment technologies can be easily automated. Ask

whether you can add automation in the future at a reasonable cost.

h the

a

he

Some systems have significant head loss through the treatment plant.

Determine if the source water pump is capable of meeting the head

loss and providing adequate system pressure and flow.

pdated

nother

If the equipment is adaptable you will not be tied to one supplier.

For example, if the vessel has a typical EBCT, then the replacement

media can be from any supplier that can provide the treatment with

the same EBCT. Also, with some modification, adsorptive media

treatment systems could be adapted to coagulation/filtration.

at my

Some suppliers have a database available such that they do not need

to pilot test their technology at your site. Some vendors will pilot

test their technology if you provide their research center with enough

water. If they will not conduct a pilot test, ask for performance

certifications and guarantees.

A row of ion exchange tanks in parallel.
19

POU/POE POU/POE

Questions Reason for Question or What to Look for in the Answer

Are the units NSF/ANSI certified?

Can I see the certification?

Ask the vendor if their units meet NSF Standard 53 or Standard 58 if it is a

reverse osmosis system. (You can also check the NSF Web site for their listing

at http://www.nsf.org/business/drinking_water_systems_center/index.)

Is the unit equipped with a warning

or shutoff device to alert the

customer that the unit is

malfunctioning or in need of service?

A warning device will be required on all POU systems. Some states do not

allow the shutoff device; contact your state regarding these requirements.

Determine how the device operates (e.g., is it based on time or water quality?)

What are some of the water quality

limitations of this technology?

Provide the vendor with your system's water quality data. Ask if there are any

limiting constituents in the water that would impact the use of their treatment

technology.

Based on my water quality, what is

the necessary frequency of service?

All treatment technologies react to specific water quality and use characteristics;

these will impact the mandatory maintenance schedule. Extensive site testing

may be necessary to get state approval for the technology and the monitoring

plan.

Can you pilot your units on a limited

number of homes? At what cost?

Also contact your state to see if pilot testing is required.

Is it necessary to oxidize the source

water to convert arsenic (III) to

arsenic (V)?

Nearly all treatment technologies are more effective at removing arsenic (III)

oxidized to arsenic (V). If the vendor indicates this is not necessary, ask for

documentation and make sure your state does not require pre-oxidation.

Is any other pre-treatment necessary? Many systems require pretreatment such as filtration and dechlorination to

protect either membranes or media.

Is chromatographic peaking a

potential risk? If so, how can it be

avoided?

Concentrating contaminants and driving them into the system can occur with

some technologies (specifically ion exchange).
20

Sources of Cos ces of Cos ces of Cost Information ormationIf you have chosen, or are still deciding on, an appropriate treatment technology, you will wantto get a feel for the cost of implementing the technology. There are many sources for costinformation, including cost models developed by EPA and other public and privateorganizations; cost information based on other treatment systems that have beenconstructed; site-specific cost estimates developed for your system by an engineer; andestimates developed by vendor and equipment suppliers.EPA has developed numerous cost estimating tools: The Arsenic Treatment Technology Evaluation Handbook for Small Systems (see http://

www.epa.gov/safewater/smallsys/arsenic_treatment_handbook_lo.pdf) has cost curves (in

1998 dollars) that can be used to estimate capital and operating costs for each of thecommon technologies.

 EPA’s Office of Research and Development (ORD) has created an Excel-based costestimating model for adsorptive media and ion exchange technologies. This program is free

of charge and available at http://www.epa.gov/ORD/NRMRL/arsenic/ARCE.xls. The costsgenerated by this model are in 2003 dollars. This and other models typically have anaccuracy of ± 30 percent.

ORD has also published cost information on the first round of EPA’s full-scale, long-term, onsite arsenic demonstration projects (see http://www.epa.gov/ORD/NRMRL/pubs/600r04201/600r04201.htm), which offers a general sense of the capital equipment andbuilding costs for these projects. Compare the system size and technology type to your system(though note that some of these costs may reflect a discounted price for equipment or mayseem high due to differing specifications, e.g., level of automation).There are other cost-estimating models available or under development by other entities suchas states and the American Water Works Association.

r!

ation will

er or vendor

have

ities. (Ask

or state for

ion.) Use the

 this brochure

e to provide

he

o get a good
21

Sources of Additional Inf ces of Additional Inf ces of Additional Information ormationhttp://www.epa.gov/safewater/arsenichttp://www.epa.gov/ORD/NRMRL/arsenic/http://www.arsenictradeshow.comPart of a coagulation/filtration treatment system in Billings, Montana.