570083010
0
RADIONUCLIDE REMOVAL
FOR
SMALL PUBLIC WATER SYSTEMS
~ Prepared by:
•O
— SMC Martin Inc.
_J 900 West Valley Forge Road
O' P. 0. Box 859
'- Valley Forge, Pennsylvania 19482
J
vi
o
^ Prepared for:
U.S. Environmental Protection Agency
Office of Drinking Water
Chester Pauls, Project Officer
401 M Street, SW
Washington, DC 20460
REGION 11 LIBRARY ' Contract No. 68-01-6285
U. S. ENVIRONMENTAL PROTECTION'
AGENCY . TOQ,
1445 ROSS AVENUE June 1983
DALLAS, TEXAS 7520?
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ACKNOWLEDGEMENT
This manual was prepared for U.S. Environmental Protection Agency under
Contract No. 68-01-6285. Mr. Chester Pauls, EPA Project Officer, provided
valuable guidance to the project. The manual was compiled by SMC Martin
Inc. in cooperation with the following:
J. E. Singley, Ph.D.
B. A. Beaudet, P.E.
L. J. Bilello, P.E.
Environmental Science and Engineering, Inc.
Gainesville, Florida 32602
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CONTENTS
I. SUMMARY AND OVERVIEW 1-1
Purpose 1-1
What are Radionuclides 1-2
Radionuclide Health Effects 1-2
Alternative Methods to Reduce Excessive
Radionuclides in Drinking Water 1-2
Designing a Radionuclide Removal System 1-5
Waste Residue Handling 1-6
Cost Estimating Procedures and Funding Sources 1-7
Personnel Requirements for the Operation and
Maintenance of Radionuclide Removal Systems 1-7
II. INTRODUCTION II-l
Structure of Matter II-l
Atomic Notation II-2
Radioactivity II-5
Units of Radioactivity II-9
Radionuclides in Drinking Water—Occurrence
and Sources II-9
Naturally Occurring Radionuclides II-9
Man-made Radionuclides 11-11
Health Effects of Low Level Radioactivity in
Drinking Water 11-12
Federal Regulations Applicable to Radionuclides
in Drinking Water 11-12
Monitoring Requirements 11-13
Natural Radioactivity 11-13
Man-made Radioactivity 11-14
Analytical Methods for Measuring Radionuclides 11-18
III. NONTREATMENT AND TREATMENT ALTERNATIVES FOR REDUCING
RADIONUCLIDE CONTAMINATION IN DRINKING WATER III-l
Nontreatment Alternatives III-l
Treating Water Supplies for Radium and Uranium Removal III-2
Lime and Lime-Soda Softening III-4
Process Description III-5
Lime-Soda Softening Equipment III-7
Radium Removal by Lime-Soda Softening HI-7
Advantages and Disadvantages of Lime-Soda
Softening for Radium Removal 111-13
Ion-Exchange Treatment III-l3
Ion-Exchange Softening (Cation Exchange) 111-14
How Ion-Exchange Softening Works 111-14
Ion-Exchange Equipment 111-18
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CONTENTS
(Continued)
III. (Continued)
Suppliers of Ion Exchange Systems 111-18
Radionuclide Removal by Ion Exchange 111-20
Advantages and Disadvantages of Ion-Exchange
Softening for Radionuclide Removal 111-22
Reverse Osmosis 111-23
Process Description 111-23
Types of Membrane Systems II1-23
Pretreatment Requirements IH-27
Other Factors Influencing Operation 111-29
Suppliers of Reverse Osmosis Systems 111-30
Radionuclide Removal by Reverse Osmosis 111-30
Advantages and Disadvantages of Reverse
Osmosis for Radionuclide Removal 111-30
IV. DESIGNING A REMOVAL SYSTEM FOR NATURALLY OCCURRING
RADIONUCLIDES IV-1
Introduction IV-1
Considerations in the Design of a Radionuclide
Treatment System IV-1
Radionuclide Removal Design Checklist IV-2
Selection of a Radionuclide Treatment System IV-5
Technical Feasibility IV-5
Limitations of Lime-Soda Softening
for Radionuclide Removal IV-5
Limitations of Ion Exchange for
Radionuclide Removal IV-5
Limitations of Reverse Osmosis for
Radionuclide Removal IV-6
Cost IV-7
Site Limitations IV-7
Compatibility with Existing Treatment Equipment IV-8
Preference IV-8
Pilot Studies for Evaluating Radionuclide Removal
Processes IV-9
Design of a Lime-Soda Softening System for Radium
Removal IV-9
Analysis Required for Designing a Lime-Soda
Softening System for Radium Removal IV-9
Pretreatment Prior to the Lime-Soda Softening
Process IV-10
Design Criteria for the Lime-Soda Softening
Radium Removal Process IV-10
Factors Which Influence Chemical Dosage in the
Lime-Soda Softening Process IV-11
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CONTENTS
(Continued)
IV. (Continued)
Sample Design of a Lime-Soda Softening Process
for Radium Removal IV-11
Laboratory Studies IV-13
Design of an Ion-Exchange Treatment System for
Radium Removal IV-14
Pretreatment Prior to an Ion-Exchange System IV-14
Analysis Required for the Design of an Ion-
Exchange System for Radium Removal IV-15
Pilot Testing of Ion-Exchange Systems for
Radium Removal IV-15
Design Criteria for an Ion-Exchange System
for Radium Removal IV-16
Sample Design of an Ion-Exchange System for
Radium Removal IV-1'6
Design of a Reverse Osmosis Treatment System for
Radionuclides IV-22
Analytical Requirements and Plant Operating
Information Required for Selection of a
Reverse Osmosis System IV-22
Pretreatment Prior to Reverse Osmosis IV-22
Procedure for Selection of Reverse Osmosis
System for Radionuclide Removal IV-25
Specifying Reverse Osmosis Modules IV-26
Posttreatment IV-29
V. WASTE RESIDUE HANDLING V-l
Characteristics of Waste Streams Generated by
Water Treatment Processes for Radionuclide
Removal V-2
Disposal Alternatives for Lime-Soda Softening Sludge V-2
Disposal Alternatives for Lime-Soda Softening
Backwash Waters V-2
Disposal Alternatives for Ion-Exchange Brine V-4
Reverse Osmosis Waste V-5
Applicable Federal Regulations V-5
VI. COST ESTIMATING PROCEDURES AND FUNDING SOURCES VI-1
Construction Costs VI-1
Introduction VI-1
Annualizing Capital Costs VI-3
Example - Ion-Exchange Softening VI-9
Operation and Maintenance Costs VI-12
Example - Ion-Exchange Softening VI-13
Ion-Exchange Operation and Maintenance Cost VI-13
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CONTENTS
(Continued)
VI. (Continued)
Example Cost Calculation
Funding Sources
Self-Financing
Grant Programs
Direct Loan Programs
Loan Guarantee Programs
Other Forms of Assistance
VI-16
VI-20
VI-20
VI-21
VI-22
VI-22
VI-22
VII. OPERATION AND MAINTENANCE VII-1
Manpower Requirements VII-1
Management and Record Keeping VII-2
Emergency Procedures VII-3
Safety Procedures VII-3
Maintenance Procedures VI1-4
Maintenance for Reverse Osmosis Systems VII-4
Maintenance for Ion-Exchange Systems VII-5
Maintenance for Lime-Soda Softening Systems VII-6
VIII. CASE HISTORIES
Lime-Soda Softening
Ion Exchange and Blending of Treated and
Untreated Water
Reverse Osmosis
VIII-1
VIII-l
VIII-3
VIII-4
BIBLIOGRAPHY
APPENDICES
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LIST OF FIGURES
Figure Page
1-1 Alternative Methods for Reducing Excessive
Radionuclide Concentrations in Drinking Water 1-3
2-1 Schematic Drawing of a Hydrogen Atom and a
Helium Atom II-3
2-2 Schematic Drawing of a Lithium Atom I1-4
2-3 Range of Nuclear Particles in Air With
the Same Energy (3 MEV). I1-8
2-4 Flow Chart for Gross Alpha Particle
Activity Monitoring (U.S. EPA, Las Vegas,
Environmental Monitoring and Support
Laboratory) 11-15
2-5 Flow Chart for Gross Beta Particle Activity
Monitoring for a Water Source not
Designated as Being Contaminated by
Effluents From Nuclear Facilities Serving
More than 100,000 Persons as Designated
by the State 11-16
2-6 Flow Chart for Monitoring Drinking Water
Samples Near a Nuclear Facility (U.S.
EPA, Las Vegas, Environmental Monitoring
and Support Laboratory) 11-17
3-1 Simplified Schematic of Lime-Soda Softening Process III-6
3-2 Solids Contact or Upflow Plant III-8
3-3 Typical Upflow, Catalytic Lime Softening Unit III-9
3-4 Lime-Soda Process, Total Hardness Removal
Fraction Versus Radium Removal Fraction 111-10
3-5 Radium Removal Fraction Versus pH of
Treatment, Lime-Soda Process 111-22
3-6 Operation Modes in a Typical Ion-Exchange Unit 111-15
3-7 Typical Pressure-Type Ion Exchange Treatment Vessel 111-19
3-8 Radium Removal Fraction Versus Total Hardness
Removal Fraction in Ion Exchange Plants,
Before Blending II1-21
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LIST OF FIGURES
(Continued)
Figure
3-9a Osmosis - Normal Flow from Low-Concentration
Solution to High-Concentration Solution 111-24
3-9b Reverse Osmosis - Flow Reversed by Application of
Pressure to High-Concentration Solution 111-24
3-10 Cutaway View of a Spiral Membrane Element 111-25
3-11 Permeator Assembly for Hollow Fine Fiber Membranes IH-26
3-12 Typical Reverse Osmosis System 111-28
4-1 Fraction of Water Needed to be Treated Versus
Raw Water Radium Concentration to Obtain Final
Concentration of 5 Pic/1 - Ion Exchange
(95% removal efficiency) IV-18
4-2 Typical RO System Design IV-27
4-3 Fraction of Water Needed Versus Raw Water
Radionuclide Concentration to Obtain
5 PiC/1 - Reverse Osmosis IV-28
6-1 General Contractor's Overhead and Fee Percentage
Versus Total Construction Cost VI-4
6-2 Legal, Fiscal, and Administrative Costs for
Projects Less than $1 Million VI-5
6-3 Legal, Fiscal, and Administrative Costs for
Projects Greater than $1 Million VI-6
6-4 Interest During Construction for Projects
Less than $200,000 VI-7
6-5 Interest During Construction for Projects
Greater than $200,000 VI-8
6-6 Construction Cost for Pressure Ion-Exchange
Softening VI-10
6-7 Operation and Maintenance Requirements for
Pressure Ion-Exchange Softening - Building
Energy, Process Energy, and Maintenance Material VI-14
6-8 Operation and Maintenance Requirements for
Pressure Ion-Exchange Softening - Labor and
Total Cost VI-15
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LIST OF TABLES
Table Page
1-1 Federal Financial Assistance Programs 1-8
2-1 Types of Nuclear Radiation I1-6
2-2 Radioactivity Terms 11-10
2-3 Summary of NIPDWR for Radionuclides 11-13
2-4 Example Calculation of Total Dose for
Man-Made Radionuclides 1-19
3-1 Treatment Techniques Applicable for
Reducing Radium and Urnaium
Radionuclides from Drinking Water III-3
3-2 Lime-Soda Softening Equipment Suppliers 111-12
3-3 Partial List of U.S. Ion Exchange Resin Producers 111-16
3-4 Partial List of U.S. Suppliers of Ion Exchange
Systems II1-20
3-5 Partial List of Reverse Osmosis System Suppliers 111-31
4-1 Radionuclide Removal System Design Checklist IV-2
4-2 Site Limitations Affecting Treatment Selection IV-8
4-3 Analysis Required for Designing an Ion-Exchange
System for Radium Removal IV-15
4-4 Bsic Design Information for Ion-Exchange System IV-17
4-5 List of Information Required for Selection of a
Reverse Osmosis System IV-23
5-1 Estimated Radioactivity and Quantity of Water
Treatment Waste Residues V-3
5-2 Summary of Disposal Alternatives for Lime-Soda
Softening Sludge V-4
5-3 Alternatives for Disposal of Ion-Exchange Brines V-6
6-1 Capital Recovery Factors for Some Combinations
of Interest (i) and Project Life (n) VI-11
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LIST OF TABLES
(Continued)
Table Page
6-2 Conceptual Design for Ion-Exchange Softening VI-11
6-3 Construction Cost for Ion-Exchange Softening
(1978 Dollars) VI-12
V
6-4 Operation and Maintenance Summary for Pressure
Ion-Exchange Softening VI-16
8-1 Reduction of a Ra-266 and Hardness, Peru,
Illinois, Before Blending VIII-2
8-2 Ra-266 Reduction, Lynwood, Illinois VIII-3
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I. SUMMARY AND OVERVIEW
PURPOSE II
This document has been prepared
to aid water utility owners,
engineers, operators and municipal
managers in understanding and
dealing with excessive radionu-
clide levels in their water
supply. It is intended to be
used for defining the problem,
developing or evaluating proposed III
solutions, and explaining to
water consumers why radionuclides
are controlled and what the
approximate cost of control will
be. Although the handbook may be IV
useful to larger utilities, it is
intended primarily to support the
water quality improvement efforts
of smaller utilities that may
lack the technical and financial
resources of larger systems.
This handbook is designed as a
technical guide to radionuclide V
removal for those smaller size
systems that have decided that
radionuclide control is desirable.
This document contains no regula-
tory policy and does not obligate
systems to use any treatment or VI
nontreatment technique to reduce
radionuclide concentrations. If
appropriate, those regulatory
requirements are or will be
established by the primacy agency
as part of its implementation of
the Primary Drinking Water
Regulations.
The handbook is divided into
eight sections, plus references, VII
as follows:
Section Subject Guide
I Summary and Overview
Introduction - Discusses the
structure of matter, the
units of radioactivity,
radionuclides in drinking
water, health effects,
federal regulations, and the
monitoring and analysis
requirements for detecting
radionuclides in water.
Nontreatment and Treatment
Alternatives - Different
approaches to solving excess
radionuclide problems.
Design of Radionuclide
Removal Systems - Describes
and compares lime-soda
softening, ion-exchange, and
reverse osmosis treatment
systems. Examples of design
calculations and lists of
suppliers are presented.
Waste Residue Handling -
Discusses disposal methods
for waste by-products gener-
ated by different radionu-
clide removal systems.
Cost Estimating Procedures
and Funding Sources - Capital
capacity, sources of loans,
grants and other financial
assistance are discussed.
The methods used to determine
costs are explained and an
example is presented to
demonstrate the use of the
method.
Operation and Maintenance -
Presents basic guidelines
for operating radionuclide
removal systems, including
water quality monitoring and
equipment maintenance.
1-1
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VIII Case Histories - Discusses
the experience of three
utilities which are treating
the water supply to remove
excess radionuclides.
WHAT ARE RADIONUCLIDES
Radionuclides are chemical ele-
ments which undergo spontaneous
nuclear decay, thereby emitting
various forms of radiation energy.
Radionuclides may originate from
both natural and man-made sources.
Radium is the naturally occurring
radionuclide of most concern in
the U. S. Radium is leached
under natural conditions into
ground waters from radium-bearing
deposits found in rock strata and
phosphate rock. Uranium, another
natural radionuclide, may also
leach into ground waters under
natural conditions. Both uranium
and radium, may also enter surface
water supplies from man's activi-
ties such as from stormwater
runoff from the tailings of
mining operations and discharges
from medical and industrial
activities. Man-made radionu-
clides may also contaminate water
supplies as a result of fallout
from nuclear weapons detonation
or accidental discharge from
nuclear power facilities. Exces-
sive levels of man-made radionu-
clides in drinking water are
anticipated only in transient
situations following a major
contaminating event.
RADIONUCLIDE HEALTH EFFECTS
Radioactivity has been known for
many years to produce detrimental
biological effects to humans,
including developmental abnormal-
ties, cancer, and death. The
primary basis for the United
States Environmental Protection
Agency (EPA) radionuclide regula-
tions for drinking water is the
carcinogenic potential of this
material. Although currently
there appears to be no completely
safe lower limit of exposure to
any radionuclide, human ingestion
of potable water which contains
radionuclides at levels below the
maximum contaminant levels (MCLs)
allowed by the National Interim
Primary Drinking Water Regulations
(NIPDWR, see Reference 2) results
in minimal health risk.
ALTERNATIVE METHODS TO REDUCE
EXCESSIVE RADIONUCLIDES IN
DRINKING WATER
If radionuclides in the drinking
water supply are excessive, steps
should be taken to reduce these
levels. Figure 1-1 depicts
alternatives available to a
utility for radionuclide removal.
As discussed in this document,
radionuclide removal can involve
significant costs. Before buying
a treatment system for radionuclide
removal, the utility should
carefully study all nontreatment
approaches as discussed in Sec-
tion III of this document. It
may also be possible to blend a.
water with excessive radionuclides
with one having little radionuclide
contamination, to produce a
blended water of acceptable
quality.
There are four practical and
available methods for reducing
excessive concentrations of
radionuclides in drinking water:
1. Blending with a water from
an alternative source having
less contamination.
1-2
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START
MONITOR
RADIONUCLIDE
LEVELS
NO
STUDY ALTERNATIVES
NONTREATMENT
ALTERNATIVES
(1)
(1) NONTREATMENT
ALTERNATIVES
New Supply
Blending
Regionalization
TREATMENT
ALTERNATIVES
(2)
(2) TREATMENT
ALTERNATIVES
Softening
Ion Exchange
Reverse Osmosis
COMPARE
COSTS
RELIABILITY
OPEATIONAL
CONSIDERATIONS
SELECT AND IMPLEMENT
BEST SOLUTION
Figure 1-1. Alternative Methods for Reducing Excessive Radionuclide
Concentrations in Drinking Water
1-3
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2. Lime, or lime-soda softening.
3. Ion exchange.
4. Reverse osmosis.
Blending may be combined with any
of the other treatment methods.
Full scale lime or lime-soda
softening plants have demonstrated
an ability to remove 60 to 94 per-
cent of radium from water, with
an average removal of about
80 percent. Laboratory tests
have demonstrated that the lime
softening process has the poten-
tial of removing between 85 and
98 percent of uranium from water.
Lime softening may be capable of
removing some man-made radionu-
clides from water; however,
studies would be necessary to
determine if this process can
effectively remove any man-made
radionuclides which may be
present.
Ion exchange can remove greater
than 90 percent of both radium
and uranium from water. Well
designed and operated plants
should be capable of consistent
95 percent removals. Although
some man-made radionuclides may
be removed from water by ion
exchange, this process should not
be depended upon as a blanket
treatment for man-made
radionuclides.
Reverse osmosis (RO) processes
can remove 90 percent or more of
radium, uranium and most man-made
radionuclides from water. RO is
the only treatment method which
may be considered as generally
applicable for treating most of
the man-made radionuclides that
may be found in water.
The lime and lime-soda softening
processes remove radium from
water in a manner similar to the
removal of hardness. Lime and
soda ash are added to the water
and combine chemically with the
hardness causing calcium and
magnesium ions, as well as any
radionuclide ions present to
convert them into insoluble
compounds. The insoluble compounds,
or precipitates, form a sludge
which can then be removed from
the water by gravity settling.
One of the main considerations in
designing a lime or lime-soda"'
softening process is the quantity
of lime and soda ash required to
be added to soften the water.
This can be estimated based' on
the raw water characteristics.
The sludge mass produced requiring
disposal, and thus disposal
costs, depend upon the amount of
hardness removed and is directly
proportional to chemical
requirements.
The ion-exchange softening process
removes hardness from water by
exchanging calcium and magnesium
ions for sodium (or hydrogen)
ions contained in the ion-exchange
resin. Radium ions are also
exchanged in this process and are
thereby removed from the water.
Because the ion-exchange process
is reversible, all of the readily
replaceable sodium or hydrogen
ions will eventually be released
from the resin and replaced by
other ions such as calcium,
magnesium and radium. Therefore,
the "exhausted" resin must be
periodically regenerated with
brine, a solution of sodium
chloride (common salt) or with a
dilute acid solution. In the
regeneration process, the calcium,
magnesium, radium, and other ions
present in the exhausted resin
are replaced with a fresh supply
of sodium or hydrogen ions from
1-4
-------
the regenerating solution. Then,
after washing the resin with
water to free it from brine or
acid, the regenerated exchange
resin is ready to soften an
additional supply of water.
Resins may also be used to remove
uranium from waters. However,
because uranium is present predom-
inantly in the anionic (negatively
charged) ion form, anionic exchange
resins are required. A mixture
of sodium chloride and sodium
bicarbonate are used for regener-
ation of the anionic exchange
resin.
The exchange capacity of the
ion-exchange resin and the quanti-
ty of salt required for resin
regeneration are primary consider-
ations in designing an ion-exchange
treatment system. This information
can be obtained from the ion-
exchange resin manufacturer once
the raw water characteristics are
known. Regenerant brine and
resin washwater streams are
contaminated with dissolved
solids and require disposal in an
environmentally acceptable manner.
Reverse osmosis is a process in
which water is forced through a
semipermeable membrane that will
not pass dissolved substances.
Thus, calcium, magnesium, radionu-
clides, and other ions in solution
will be removed from the product
water as it passes through the
membrane. The main design consid-
eration for a reverse osmosis
system is the pumping pressure
required to force the water
through the membrane. The pumping
pressure is directly dependent on
the concentration of dissolved
solids in the raw water. Manu-
facturers of reverse osmosis
systems can supply much of the
required design information once
the raw water characteristics,
including dissolved solids, are
known. The reject stream from a
reverse osmosis plant contains
high levels of dissolved solids
and requires special disposal
considerations.
Because the treated water following
ion-exchange or reverse osmosis
treatment is normally much lower
in radionuclide content than
required by the standards, it may
be blended with the raw water to
produce a finished water of
acceptable quality. Blending of
treated and raw water is more
economical than treating all of
the raw water because the treat-
ment facilities are designed
based on the volume of water
treated. The portion of raw
water to be treated so that the
blended water radionuclide level
is acceptable is dependent upon
the raw water radionuclide concen-
tration and the performance of
the treatment system with respect
to both radionuclides and other
(conventional) regulated parameters.
DESIGNING A RADIONUCLIDE REMOVAL
SYSTEM
Design of a radionuclide removal
system involves these main
considerations:
1. Characteristics of the raw
water.
2. Required radionuclide reduc-
tion to achieve an acceptable
water quality and to comply
with primary drinking water
regulations.
3. Quantity of water to be
treated.
1-5
-------
Lime or lime-soda softening is
most applicable to waters of
moderate to high total hardness
(about 120 to 400 mg/1 of total
hardness [TH] as CaCCO where the
total dissolved solids are about
750 mg/1 or less. When the raw
water source is harder than about
400 mg/1, large chemical require-
ments often render lime or lime-
soda softening impractical. Lime
softening may not be practical
for radionuclide removal from low
hardness «120 mg/1 TH as CaCO )
waters, although site specific
data are unavailable on such an
application. Bench or pilot
scale testing should be conducted
to determine the performance and
cost effectiveness of lime soften-
ing for radionuclide removal from
low hardness waters prior to
implementing such a system.
Ion exchange for radionuclide
removal is applicable to waters
of very low to moderate hardness
and total dissolved solids (IDS)
(about 0 to 400 mg/1 of TH as
CaCO- and 500 mg/1 or less).
Since TDS levels often increase
slightly through a typical brine
regenerated ion exchange system,
the 500 mg/1 TDS limitation on
ion exchange systems is necessary
to prevent a finished water from
exceeding the 500 mg/1 secondary
MCL for TDS.
For the highly mineralized water
cases, hydrogen cycle (acid
regenerated) ion exchange units
could be used which would produce
an acceptable water quality for
TDS; however, the practical
implications of its use for small
systems frequently preclude its
serious consideration.
Reverse osmosis, although more
expensive than the other alterna-
tives, is most applicable to
waters above 500 mg/1 TDS. RO
can be used, however, to remove
radionuclides in water of lower
mineral content.
Raw water radionuclide content
must be considered in selecting a
treatment system capable of
producing a finished water that
meets NIPDWR standards. For
instance, lime or lime-soda
softening processes should not be
considered when the (unblended)
raw water radium concentration is
greater than 25 picoCuries per
liter (pCi/1), since the average
radium reduction of 80 percent
would not be adequate to meet the
radium standard of 5 pCi/1.
(Sorg has indicated a range of
removals between 75-96 percent.)
Ion exchange or reverse osmosis
would be applicable to source
waters with radium concentrations
greater than 25 pCi/1 up to
50-100 pCi/1.
In designing a water treatment
system with a treatment capacity
of 0.5 MGD or less, the availabil-
ity of commercial equipment is a
major constraint because custom
designed and constructed installa-
tions are generally not cost
effective. Lime or lime-soda
softening systems are commercially
available for systems greater
than about 75,000 gpd. Ion
exchange and reverse osmosis
systems are commercially available
for the very smallest (about
100 gpd or less) to the larger
(greater than 0.5 MGD) system
sizes.
WASTE RESIDUE HANDLING
Each of the radionuclide removal
processes previously described
generates a waste stream of some
1-6
-------
sort. These waste streams include
lime and lime-soda softening
sludge and backwash water, ion-
exchange brine and resin rinse
water, and reverse osmosis reject
water.
These wastes are not under the
jurisdiction of the Federal
Nuclear Regulatory Commission
(NRD) because they are naturally
occurring. In addition, the
radionuclide content of these
waste streams is well below the
level of radioactive wastes
regulated by the NRC for those
wastes where they do have
jurisdiction.
The wastes still, however, must
be handled in an environmentally
acceptable manner. Available
options for waste residue handling
and disposal should be considered
when selecting a treatment process
for radionuclide removal.
Federal and state National Pollu-
tant Discharge Elimination System
(NPDES) regulations apply if the
waste streams are discharged to a
navigable waterway. EPA or primacy
state permits are required for such
discharges. Waste residue injected
underground is regulated under
the authority of the Safe Drinking
Water Act's Underground Injection
Control (UIC) program. Disposal
by deep well injection requires a
permit which is issued by EPA or
primacy state authorities.
Landfilling or land application
of water plant wastes is not
currently regulated under the
federal Resource Conservation and
Recovery Act's (RCRA) Hazardous
waste management program. Land
disposal of such wastes is gen-
erally regulated under the juris-
diction of state and local regula-
tory agencies who should be
consulted prior to choosing a
treatment process alternative.
COST ESTIMATING PROCEDURES AND
FUNDING SOURCES
Section VI of this document
provides a procedure for estimating
costs for radionuclide removal.
It begins with an explanation of
construction costs, their annuali-
zation and adjustment for inflation.
Operation and maintenance costs
are then discussed. A method for
determining total annual costs
and costs per thousand gallons of
product water is then provided.
Sources of financial assistance,
in the form of loans, loan guaran-
tees, or outright grants, are
very limited. The principal
federal financial assistance
programs available are shown in
Table 1-1.
PERSONNEL REQUIREMENTS FOR THE
OPERATION AND MAINTENANCE OF
RADIONUCLIDE REMOVAL SYSTEMS
For lime-soda softening, ion-
exchange softening, or reverse
osmosis treatment plants processing
less than 0.5 million gallons per
day (MGD), regular sampling and
monitoring will be necessary to
ensure continued reliable operation.
The operator may or may not be
required by the individual states
to be full-time but can be expected
to spend several hours at the
plant each day for routine monitor-
ing and preventive maintenance
activities. The operator should
have basic mechanical and electrical
skills and should have a working
knowledge of fundamental chemistry
and be able to perform routine
tests for hardness, alkalinity,
pH and TDS, as well as be able to
1-7
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TABLE 1-1
FEDERAL FINANCIAL ASSISTANCE PROGRAMS
Agency
Fanners Home
Administration
Department of
Interior
Small Business
Administration
Program Description
(1) Cooperative grants up to 75 percent of
project cost for publicly owned rural
systems serving fewer than 10,000 persons.
(2) Loan guarantees up to 90 percent of
loan face value for public or private
rural utilities, emphasizing those
serving fewer than 2,500 persons.
(3) Direct loans up to 75 percent of
project cost.
(1) Direct loan programs for nonfederal
entities in the 17 western states.
(2) Financial assistance for systems
serving American Indians.
(1) Loan guarantees up to 90 percent of face
value, maximum $500,000, for privately
owned utilities.
sample for radionuclides and
interpret results from outside
laboratories. To assist the
operator in sampling, equipment
lubricating, cleaning and mainte-
nance, and general housekeeping, a
maintenance helper or semiskilled
laborer should also be available.
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II. INTRODUCTION
Radionuclides are chemical ele-
ments which undergo spontaneous
nuclear decay, thereby emitting
various forms of radiation energy.
They may originate from both
natural and man-made sources.
The National Interim Primary
Drinking Water Regulations
(NIPDWR) on radionuclides contain
numerous technical terms which
must be understood to determine
whether the water supply is in
compliance with the radionucllde
regulations and to obtain maximum
benefit from the treatment infor-
mation presented in this document.
A brief explanation of these
terms and related concepts of
radiation are presented in this
section. The section is organ-
ized as follows:
STRUCTURE OF MATTER
Atomic Notation
Radioactivity
Units of Radioactivity
RADIONUCLIDES IN DRINKING WATER -
OCCURRENCES AND SOURCES
Naturally Occurring Radionu-
clides
Man-made Radionuclides
HEALTH EFFECTS OF LOW LEVEL
RADIOACTIVITY IN DRINKING WATER
FEDERAL REGULATIONS APPLICABLE TO
RADIONUCLIDES IN DRINKING WATER
Monitoring Requirements
Natural Radioactivity
Man-made Radioactivity
Analytical Methods for
Measuring Radioactivity
STRUCTURE OF MATTER
All matter is composed of basic
substances called elements.
There are 92 natural elements,
including, for example: iron,
hydrogen, oxygen, chlorine,
sulfur and carbon. Each element
has its own chemical character-
istics, and cannot be separated
into simpler substances by ordinary
chemical means. An atom is the
smallest unit of an element that
possesses all the characteristics
of the element.
Atoms are made up of fundamental
particles called electrons,
protons, and neutrons. The
electron was first discovered as
the basic unit of electricity.
It is a very tiny, negatively
charged particle considerably
lighter than an atom. The proton
is a positively charged particle
having exactly the same magnitude
of charge as the electron; however,
it is much larger than the electron
in mass, having approximately
1,840 times the electron mass. A
neutron is a particle of neutral
charge, and its mass is approxi-
mately equal to that of a proton.
An atom consists of a heavy
concentration of mass at the
center (the nucleus) surrounded
by shells of electrons in different
orbits. The primary constituents
of the nucleus are neutrons and
protons. Since the orbital
electrons have a negative charge
and are equal in number to the
protons, the atom is neutral in
overall charge. The atoms of all
of the known elements can be
organized according to the structure
of their nuclei. The simplest
atom known is hydrogen. It
contains only one proton as its
nucleus and, therefore, has only
one electron in orbit around the
II-1
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nucleus (see Figure 2-1). The
next simplest atom is helium. It
contains two protons in its
nucleus along with two neutrons
and has two electrons in orbit
(see Figure 2-1). Through years
of research, scientists have
discovered that electrons in
orbit exist in certain arrange-
ments. Electron configuration
gives the atom properties which
determine its chemical reactivity,
ranging from nonreactive to
highly reactive. Based on this
discovery (which resulted in the
identification of electron "shells"
and "orbits") elements can be
grouped into chemical families.
For example, the lithium atom,
shown in Figure 2-2, which has
three protons and four neutrons
in the nucleus, has two electrons
in one orbit and a third in an
outer orbit. This atom is rela-
tively reactive chemically.
Other atoms with a single outer
electron; such as hydrogen,
sodium, potassium, rubidium and
cesium, have chemical properties
similar to (but not identical
with) those of lithium. Radium,
which has two outer electrons, is
chemically similar in behavior to
calcium, which also has two outer
electrons. For example, radium,
like calcium, becomes incorporated
into material such as bone when
ingested by humans.
Only a certain number of positions
in each orbit are available for
electrons to occupy. Electrons
of an atom tend to occupy all
available positions in an orbit
until its electron capacity is
achieved. Higher orbits are then
filled in succession. By putting
more energy into the atom, elec-
trons can be made to move to
outer (higher energy state)
orbits, leaving some lower energy
level positions unoccupied. The
atom is then said to be in an
"excited" state. From here,
electrons will spontaneously
"fall" to lower orbits, much like
water flows downhill, until the
lower energy level orbits are all
filled and the atom returns to
its normal state. The energy
lost in this process is emitted
as high energy electromagnetic
radiation, such as visible light
or x-rays. An example of this
concept is a neon lamp. The
electric current passing through
the neon gas knocks some of the
electrons into higher shells, and
as they return to their normal
state, a characteristic light is
given off. This phenomenon,
however, accounts for only one
kind of radiation and it is not
generally the cause of the radio-
activity encountered in drinking
water supplies. To facilitate an
understanding of these causes,
some additional information about
atomic structure is presented in
the following subsections.
Atomic Notation
In order to simplify discussions
concerning elements and atoms, a
standard notational form is used
to talk about atoms. It is based
upon the primary characteristics
of the atom. The first of these
characteristics is the number of
protons in the nucleus of the
atom, as discussed earlier, which
in a neutral atom is also the
number of electrons contained in
orbits around the nucleus. This
number, which determines the
element to which the atom belongs,
is called the atomic number.
This is a unique number for each
and every element; in other
words, each element is character-
ized by a nucleus which contains
a specific number of protons.
This establishes the chemical
properties of each element.
11-2
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HYDROGEN ATOM
ELECTRON
ELECTRON ORBIT
PROTON
HELIUM ATOM
ELECTRON
J PROTON
NUCLEUS < NEUTRON
ELECTRON ORBITS
Figure 2-1. Schematic Drawing of a Hydrogen Atom and a Helium Atom
II-3
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NORMAL ENERGY
LEVEL ORBITS
3 PROTONS (+)
NUCLEUS
ORBITAL
ELECTRONS
HIGHER
'ENERGY
ORBITS
Figure 2-2. Schematic Drawing of a Lithium Atom
II-4
-------
The second primary characteristic
is the number of neutrons in the
nucleus, a factor which to some
degree determines the nuclear
characteristics of the atom.
Variation in the number of neu-
trons does not change the chemical
properties (the element is the
same because the number of protons
has not changed) but it produces
considerable change in the stabil-
ity of the element in regard to
its tendency for radioactive
decay. Atoms with the same
number of protons but different
number of neutrons are called
isotopejs. Not all isotopes of an
element are radioactive, but some
are. The total number of protons
and neutrons in the nucleus is
called the atomic mass number.
The atomic mass number is used to
label and distinguish isotopes of
the same element, which have the
same atomic number (number of
protons in the nucleus).
For example, if an atom has
88 protrons, it is radium, whose
chemical symbol is Ra. There are
two well known isotopes of Ra:
one contains 138 neutrons, the
other 140 neutrons. Since the
atomic mass number is the total
number of protons and neutrons in
the nucleus, the two isotopes of
Ra have atomic masses of:
88 +
88 +
138
140
226, and
228.
Since the atomic number is the
number of protons in the nucleus,
and this is unique for each
element, it becomes synonymous
with the element's name. Sym-
bolically, the Ra isotopes can be
uniquely identified in shorthand
notation as:
226
Ra and
228
Ra.
It is also common and acceptable
to^write theaeftabbreviations as:
Ra and Ra , or Ra-226 and
Ra-228. The latter form is used
when superscripts are awkward.
Atomic mass numbers determined
using the total number of protons
and neutrons in the nucleus, are
not the exact masses of the atom.
Although they only reflect the
total number of protons and
neutrons, they do, however,
provide a rough approximation of
the actual masses. The atomic
mass number is used to determine
the energy released in radioac-
tive reactions in accordance with
Einstein's well known equation —
E - MC , which relates the energy
available from nuclear transfor-
mations to the change in mass of
the nucleus.
Radioactivity
Considerable energy is stored in
the nucleus of an atom. Certain
types of nuclei are by nature
unstable. These unstable nuclei
can attempt to reach a stable
state by giving up some of their
energy, or more technically, by
emitting radiation. Three basic
types of radiation are usually
emitted: alpha ( * ), beta ( 6 ),
and gamma ( y ). Table 2-1
summarizes these three types of
radiation.
Alpha and beta radiations are
actually particles. The alpha
particle is a close combination
of two protons and two neutrons.
It is thus positively charged (+2)
and is in effect a fast-moving
helium nucleus. In fact, when an
alpha particle is slowed down
enough, it will pick up two stray
electrons and become a helium
II-5
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TABLE 2-1
TYPES OF NUCLEAR RADIATION
Radiation Type
alpha particle
beta particle
gamma ray
Emitted Particles
helium nucleus (two
protons plus two
neutrons)
nuclear electron
high energy
electromagnetic
radiation
Process Symbol
alpha decay at*
beta decay /6
gamma decay y
atom. The range of an alpha
particle in air is only about
5 centimeters. The beta particle
is really nothing more than a
fast-moving electron which is
ejected from the nucleus of an
atom. Like all electrons, it has
a negative charge. It has a
range, dependent upon its energy,
of about 5 meters in air. On the
other hand, gamma radiation is a
"form of electromagnetic radiation
similar to x-rays. It is a very
high-energy, high-frequency
radiation, which cannot be easily
stopped or absorbed. Like x-rays,
gamma rays have very strong
penetration ability. Their range
in air is hundreds of meters.
Alpha radiation occurs when an
alpha particle is emitted from
the nucleus of an atom, by a
process known as alpha decay.
Beta radiation occurs when a beta
particle is emitted from a neutron
in an atom's nucleus. The neu-
tron decays into a high energy
electron (beta particle) and a
proton which remains in the
nucleus. These decay processes
which change the number of pro-
tons remaining in the nucleus
result in the formation of a new
element as a result of the radio-
active emission (since the number
of protons in the nucleus changes).
Gamma radiation is the result of
electromagnetic effects which may
be thought of as changes in the
charge and current distributions
of the nuclei. Gamma radiation,
although resulting in restruc-
turing of the elect©magnetic
properties of the nucleus, does
not result in formation of a new
element.
Unlike gamma decay, alpha and
beta decay leads to the formation
of different elements. The
isotope that decays is called the
parent. The resulting isotope (a
different element) is called the
daughter. For example, Ra-226
decays by emitting an alpha
particle. In this process the
atomic mass number is reduced
by 4 (an alpha particle consists
of two protons and two neutrons)
to 222 while the number of protons
is reduced by 2 to 86. Therefore,
II-6
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the daughter formed is Radon
(Rn). Rn is also radioactive and
also decays (at a different rate)
by the emission of an alpha
particle to form the daughter
polonium (Po), with the atomic
number 84 and atomic mass of 218.
These reactions can be written in
shorthand fashion as follows:
226.
88
222
86
,Ra-
In
Ra-
Po
>
where the atomic number and atomic
mass numbers have been included
and the alpha particle is written
as helium with its atomic number
and mass number. Note that the
atomic numbers and atomic mass
numbers balance (sum to the same
total) on each side of the equa-
tions. Beta decay causes the
atomic number to increase by one
and can be described as the con-
version of a neutron in the nu-
cleus to a proton and the emis-
sion of an electron- An example
of beta decay is R8Ra8 which
decays to actinium (
reaction is written:
This
228
28
Ac + B
where the greek symbol B is
used to designate the beta par-
ticle and the minus sign shows
that it is an electron. The
atomic numbers and atomic mass
numbers again balance since the
atomic number for an electron
is -1 and its atomic mass number
is zero. Gamma decay changes
neither the atomic number nor the
element; it only involves a loss
of energy. Alpha, beta, and
gamma radiations have many dif-
ferent energies and masses and
thus produce different effects as
they interact with matter. Each
is capable of knocking an electron
from its orbit around the nucleus
and away from the atom in a
process called ionization.
Ionized particles can be detected
with relative ease and are there-
fore used to indirectly measure
ionizing radiation. Radiation
can also be nonionizing. Non-
ionizing radiation includes
light, microwaves, and radio
waves. Both ionizing and non-
ionizing radiations can be bene-
ficial or harmful to humans.
In addition to their different
methods of decay, different
isotopes decay at different
rates. The different rates of
decay are characteristic to each
isotope. The concept of half
life is used to quantitatively
describe these differences. The
half life of an isotope is the
time required for one half of the
atoms present to decay. Half
lives can range from billions of
years or more (the half life of
ura.nium-238 [U-238] is 4.5 x
10 yr) to millionths of seconds
(the half life of polonium-214
[Po-214] is 164 x 10~ sec) and
even less.
Another way to describe the
differences between the nuclear
radiations is their ability to
penetrate matter. A comparison
is shown in Figure 2-3. In
general, most alpha particles can
be stopped by a piece of aluminum
foil while most gamma rays can
pass through the human body (as
do x-rays). The fact that the
alpha particle can be stopped in
such short distances, shows that
it deposits more of its energy in
a small distance; thus it is
capable of doing more damage per
unit volume than the other radia-
tions, which is why alpha radia-
tion is primarily of concern when
inhaled or ingested.
II-7
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/—Alpa particle w w „.
/ /—Distance for which the
4
Beta particle / gamma ray intensity is
reduced by a factor of
two
10cm Im 10m 100m 1000m
Figure 2-3. Range of Nuclear Particles in Air With the
Same Energy (3 MEV). Note that the scale is
logarithmic.
II-8
-------
Many isotopes such as potassium-40
(K-40) found in human bodies, the
carbon-14 (C-14) produced by
cosmic rays and used to date old
manuscripts, and the naturally
occurring radioactive series
exist naturally. There are three
naturally occurring radioactive
series: the uranium (U), thorium
(Th) and actinium (Ac) series.
These include a sequence of
alpha, beta, and gamma decays
involving the heavy nuclei of
these elements. The series start
with U-238, Th-232 and U-235,
respectively, and all end with a
different stable isotope of
lead (Pb). In the middle of each
series a different isotope of Rn
is formed which accounts for its
prevalence.
Units of Radioactivity
Generally, units such as milli-
grams per liter (mg/1), micrograms
per liter (ug/1), or parts per
million (ppm) are used to describe
the concentrations of pollutants,
toxic or hazardous substances
based on their chemical properties.
For the radionuclides, it is
their radioactive properties and
their relation to dosage and
exposure that are of primary
concern.
When determining the potential
effect of radioactivity on human
health, the number of alpha,
beta, and gamma particles is more
important than the mass of radio-
nuclide. Thus, it is essential
to have a unit that expresses the
activity or number of particles
emitted. The activity is related
to the half life, and longer half
lives mean lower activity. The
curie is the term used to express
this activity and is that quanti-
ty of a radionuclide that results
in 3.7 x 10 decays, disintegra-
tions, or emissions per second.
By definition, one gram of radium
is said to have 1 curie (1 ci) of
activity. By comparison, 1 gm of
U-238 has an activity of 0.36 mil-
lionths of a curie (or 0.36 micro-
curie).
Terms or units that are used to
describe radioactivity dosage or
adsorbtion are described in
Table 2-2.
Further discussion on unit mea-
sures of radioactivity, and
methods to calculate dosage, are
presented in the Appendix.
RADIONUCLIDES IN DRINKING WATER--
OCCURRENCES AND SOURCES
Naturally Occurring Radionuclides
Radium is the most common radio-
nuclide of current concern found
in water sources in the United
States. It is found particularly
throughout the Midwest and parts
of Florida. Numerous studies on
ground-water supplies in areas of
radium-bearing deposits have
shown average radium concentra-
tions of about 0.5 picocuries per
liter (pCi/1). A picocurie is
1.0 x 10 curie. Maximum
concentrations, however, exceed
50 pCi/1. Elevated levels of
radium in ground water in Iowa
and Illinois are thought to be
caused by the leaching of radium
from radium-bearing rock strata
into the deep sandstone aquifers.
In parts of Florida, elevated
levels are caused by leaching of
radium from phosphate rock de-
posits into the Floridan aquifer.
High radium levels have also been
found in surface runoff water in
the vicinity of uranium-rich
deposits in Colorado and New
Mexico.
II-9
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TABLE 2-2
RADIOACTIVITY TERMS
rep
rad
rem
Definition
A unit of energy flux used to describe
the rate of exposure to X or gamma rays.
The amount of energy adsorbed by
tissue as a result of radiation.
The amount of energy adsorbed by any
medium as a result of radiation.
The adsorbed dose of radiation in rads
times the ratio of the biological
effectiveness of the radiation con-
sidered to that for 200 kilovolt poten-
tial x-rays (relative biological
effectiveness [RBE]).
EPA (EPA-470/9-76-003) has esti-
mated that as many as 500 United
States public water supplies may
exceed the 5-pCi/l radium MCL.
Most of these are ground-water
supplies serving small systems of
0.5 million gallons per day (MGD)
or less.
Chemically, radium is a metal,
and a member of the group of
metals which include magnesium,
calcium, strontium, and barium.
These metals show similar chemical
behavior; thus, radium is trans-
ported in the environment in a
manner similar to that of calcium
and magnesium. For example, both
calcium and radium, when ingested
by humans, are deposited in the
bones. Treatment techniques for
removing radium from water sup-
plies are similar to techniques
used to soften (remove calcium
and magnesium from) hard water.
In water, radium generally loses
its two outer^electrons and
occurs as Ra . The two chem-
ically similar isotopes of radium,
Ra-226 and Ra-228, exist in
potable water supplies. Ra-226,
is an alpha particle emitter;
Ra-228 is a beta particle emitter.
Uranium, another naturally-
occurring radionuclide, Is present
in uranium-rich sandstone and
shales in Colorado, New Mexico,
and other western states, and is
also found in phosphate rocks in
the phosphate deposits of central
Florida. Uranium can be found at
picocurie per liter (pCi/1)
levels in most U. S. surface and
ground waters, although it is
somewhat more common in ground
waters. The average concentra-
tion of uranium in United States
water supply sources has been
determined by EPA in a recent
study under Interagency Agreement
No. EPA 79-D-X0674 to be about
1.73 pCl/1, with a range of from
0.07 to 652 pCi/1. EPA estimates
that from 0.1 percent to 3 percent
of the 40,000 community water
11-10
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systems in the U. S. contain in
excess of 10 pCi/1 uranium. Most
of the systems with high uranium
levels are expected to be small
systems of less than 0.5 MGD
located in the western states.
Uranium, a heavier element than
radium and less chemically active,
is generally found in natural
waters in a complex ionic form.
The particular form of a uranium-
containing ion found in a natural
water is known to vary with pH.
At the pH of most natural waters,
between 6 and 8 or above, the
uranyl carbonates (UO CO*
2K2C03) and (U02CO • 22N02CO )
predominate. Uranium usually
occurs naturally as the alpha
particle emitting isotopes U-238
and U-234.
One other naturally occurring
radioactive element which may be
present in water supplies deserves
brief mention - the element
Radon.
Radon, a noble (highly stable and
inert chemically) gas, occurs in
nature from the radioactive decay
of uranium and radium. All three
of the common radioisotopes of
radon (Rn-219, Rn-220, and Rn-222)
are alpha emitters. Although
rarely present in community water
supplies at levels which would
cause concern, radon, when present
in, drinking water, is generally
found in dissolved form in ground
waters. It may be removed from
drinking water supplies by gentle
aeration. Because so little is
presently known about radon
occurrence, it is being investi-
gated further.
Man-made Radionuclides
Man-made radionculides may occur
in drinking water sources as a
result of fallout associated with
nuclear weapons testing or through
accidental discharges from indus-
trial, commercial, or nuclear
power facilities. Man-made
radionuclides are primarily beta
or gamma emitters. Strontium-90
and tritium are the most common
man-made radionuclides found in
surface waters. They generally
occur as a result of fallout from
nuclear weapons testing. The
maximum contaminant levels con-
tained in the National Interim
Primary Drinking Water Regulations
are well above the range of
concentrations of these radio-
nculides which currently exist in
United States waters. Available
data indicate strontium-90 con-
centrations are 1 pCi per liter,
corresponding to a dose equivalent
to bone marrow of less than
0.5 millirem annually. Tritium
concentrations in surface water
rarely exceed 1,000 pCi per
liter, corresponding to a dose
equivalent of less than 0.2 mil-
lirem per year.
As stated in EPA 570/9-76-003,
EPA does not expect the maximum
contaminant levels for radioac-
tivity would apply to one-time
situations such as might follow a
major contaminating event. In
accident situations it is neces-
sary to balance, on a case-by-
case basis, the potential risk
from radiation exposure against
the practicality and consequences
of any measures taken to reduce
that risk. In such situations
Federal guidance published in the
Federal Register Notices of
August 22, 1964 and May 22, 1965
apply and the emergency plans of
the States, as provided for in
Section 1413(A)(5) of the Safe
Drinking Water Act should reflect
this Federal Guidance.
11-11
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HEALTH EFFECTS OF LOW LEVEL
RADIOACTIVITY IN DRINKING WATER
Human bodies may be exposed to
both external and internal radioac-
tivity. Internal exposure occurs
when drinking water is consumed
or air containing radionuclides
is inhaled. When a radioisotope
enters the body by ingestion or
Inhalation (in the case of a gas
such as radon), it will concen-
trate at some place in the body
depending on its properties. The
radionuclide may remain for
relatively long periods of time,
in some substances, i.e. bone,
whereas it will pass through
others quickly. Adverse health
effects in humans result from the
ionizing effect of radiation
which causes damage to internal
organs and tissue.
The National Academy of Science
reports that radiation may cause
cancer of virtually any type or
at any place in the body given
the right conditions of irradia-
tion and host susceptibility.
The primary basis for the EPA
radionuclide regulations for
drinking water is the carcinogenic
(cancer causing) potential of
this material.
Ionizing radiation damage in
humans can also cause genetic-
defects (abnormalities in future
generations). There appears to
be no completely safe lower limit
of exposure to any radionuclide;
however human consumption of
potable water which contains
radionuclides at levels below
MCLs allowed by the National
Interim Primary Drinking Water
Regulations (NIPDWR) results in
very low health risk.
FEDERAL REGULATIONS APPLICABLE TO
RADIONUCLIDES IN DRINKING WATER
The present regulations covering
radioactivity were promulgated
July 9, 1976 in the Federal
Register (Vol. 41, No. 133,
pages 28404-28409). The present
discussion provides only a simpli-
fied description of these regula-
tions. It should not be used for
legal purposes in lieu of the
actual regulation.
The maximum contaminant levels
for radionuclides in drinking
water are 5 pCi/1 of radium
(combined Ra-226 and RA-228),
15 pCi/1 of gross alpha particle
activity (all sources of emit-
ters except uranium and radon),
and a total dose equivalent of
4 millirem (mrem)/yr for man-made
radioactivity. Table 2-3 summa-
rizes the radionuclide MCLs.
Uranium and radon are both excluded
from the current regulations but
it is anticipated that they may
be regulated in the future.
Uranium was excluded because its
regulation is complicated because
uranium is both chemically and
radiologically toxic. A nonfeder-
ally enforceable guidance limit
of 10 pCi/1 is being considered
for uranium. Radon is excluded
because it is a gas, and has
rarely been found present in
water at concentrations high
enough to exceed the MCL for
alpha emitters. When radon, a
chemically unreactive heavy gas,
leaves the water and enters the
surrounding air, it accumulates
in buildings or other enclosed
spaces where it may be inhaled by
humans, causing concern to health
officials. This problem with
radon is not thought to be wide-
11-12
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TABLE 2-3
SUMMARY OF NIPDWR FOR RADIONUCLIDES
MAXIMUM CONTAMINANT LEVELS FOR RADIUM-226, RADIUM-228, AND GROSS ALPHA
PARTICLE RADIOACTIVITY (excluding radon and uranium)
Combined Ra-226 and Ra-228
Gross alpha particle activity
5 PCi/l
15.pCi/1
MAXIMUM CONTAMINANT LEVELS FOR BETA PARTICLE AND PHOTON RADIOACTIVITY
FROM MAN-MADE RADIONUCLIDES
The average annual concentration of beta
particle and photon radioactivity from man-made
radionuclides in drinking water shall not
produce a total body or internal organ dose
equivalent greater than 4 mrem per year. For
the radionuclides tritium and strontium, the
MCLs corresponding to the dose equivalent
requirements are:
Tritium (total body)
Strontium-90 (bone marrow)
20,000 pCi/1
8 pCi/1
Source: Federal Register, 1976 (Vol. 41, No. 133, pages 28404-28409)
spread, however, and control of
radon in the air is not part of
the current National Interim
Primary Drinking Water Regulations.
Monitoring Requirements
Compliance is based on the anal-
ysis of an annual composite of
four consecutive quarterly samples,
or the average of the analyses of
four samples obtained at quarterly
intervals. This analysis to
determine compliance must be
repeated every four years under
ordinary operating conditions.
However, the procedure must be
repeated upon any major change in
the water supply or addition of
new water sources. In addition
to the sampling and analytical
program described above, each
state may require further moni-
toring for water supply systems
located near nuclear facilities.
Natural Radioactivity
The determination of concentra-
tions of natural radioactivity
begins with the measurement of
the gross alpha particle activ-
ity, which using current analyti-
cal techniques measures the total
of all alpha emitters except
radon. This measurement is used
as a screening technique. If the
gross alpha particle activity is
11-13
-------
less than 5 pCi/1, the sample is
In compliance. If the gross
alpha particle activity is greater
than 15 pCi/1 the maximum contam-
inant level (MCL) may be exceeded
and a decision scheme is followed
as shown in Figure 2-4 to deter-
mine if the water exceeds the
MCL.
The first step in the decision
scheme is to measure uranium
(which is not regulated under the
NIPDWR) and to subtract its
activity from the gross alpha
count. If the resultant activity
is greater than 15 pCi/1, the
source is not in compliance. If
the resultant activity is less
than 5 pCi/1, the source is in
compliance.
If the gross alpha particle
activity is greater than 5 pCi/1,
the activity of Ra-226 must be
determined. Then, if the Ra-226
concentration is greater than
3 pCi/1, the RA-228 activity must
be determined. The total of
Ra-226 and Ra-228 must not exceed
5 pCi/1 (the MCL for radium) for
the source to be in compliance.
Man-made Radioactivity
The measurement of man-made
radioactivity levels is required
for surface water treatment
systems that serve more than
100,000 people. The gross beta
particle activity is used as a
screening technique (see Fig-
ure 2-5). If the gross beta
particle activity is less than
50 pCi/1, then just tritium and
strontium-90 (Sr-90) activities
must be determined. These iso-
topes must be measured individu-
ally because the test method for
gross beta does not measure
either tritium or strontium-90.
Tritium is determined by liquid
scintillation. Dissolved stron-
tium-90 is determined by beta
counting after a lengthy chemical
separation procedure that removes
other fission products. SR-90 is
one of the most toxic fission
products, and therefore its
concentration is limited to
8 pCi/1. As shown in Figure 2-5,
H-3 (tritium) must be less than
20,000 pCi/1 and SR-90 less than
8 pCi/1 for the water supply to
be in compliance. In addition,
the combination of these two must
not result in an absorbed dose
exceeding 4 mrem/yr.
To determine the total dose, the
relationship that 20,000 pCi/1
for H-3 results in a dose of
4 mrem/yr and that 8 pCi/1 for
Sr-90 also results in a dose of
4 mrem/yr must be used. The dose
resulting from combinations of
these radionuclides at various
concentrations can be determined
by simple proportion. For
example:
— 15,000 pCi/1 of H-3 (or, 75%
of 20,000 pCi/1) results in
a dose of 3 mrem/yr (or, 75%
of 4 mrem/yr).
— 6 pCi/1 of Sr-90 (or, 75% of
8 pCi/1) results in a dose
of 3 mrem/yr (or, 75% of
4 mrem/yr).
Thus, in the above example, each
radionuclide individually would
pass the first two tests (i.e.,
result in a dose less than
4 mrem/yr), but together they
would exceed the limit, and the
water would not be in compliance
with the MCL.
If the gross beta particle activi-
ty is greater than 50 pCi/1, then
the water sample must be analyzed
II-14
-------
OBTAIN SAMPLE
MEASURE
GROSS ALPHA
IS GROSS ALPHA
> 5 pCi/l
No
MEASURE
Ra-226
IS Ra-226
> 3 pCi/l
No
MEASURE
Ra-228
IS Ra-226
PLUS Ra-228
> 5 pCi/l
No
Yes
IS GROSS ALPHA
! >BpCI/l i
MEASURE
URANIUM
No
IS GROSS
ALPHA
MINUS
ALPHA
> 15 pCi/l
Yes
H
COMPLIANCE
NON-COMPLIANCE
Figure 2-4. Flow Chart for Gross Alpha Particle Activity Monitoring
(U.S. EPA, Las Vegas, Environmental Monitoring and
Support Laboratory). Note that it is not an NIPDWR
requirement that radon and uranium be measured if the
gross alpha activity is greater than 15 pCi/l.
11-15
-------
OBTAIN
WATER SAMPLE
1ASI
I MEASURE
GROSS BETA
ANALYZE
TO IDENTIFY
RADIONUCLIDES,
DETERMINE
COMPLIANCE
WITH 141.16
Y«s
IS BETA
>SOpCI/l
No
MEASURE
TRITIUM AND
St-90(l)
IS ^
TRITIUM
>20,000 pCi/l
ANNUAL DOSE
FROM
RADIONUCLIDES
FOUND IS
No
IS
Sr-90
>8pCl/l
ANNUAL DOSE
FROM
TRITIUM and Sr-90
_ IS > 4mr«m/yr
No
COMPLIANCE
YM
-M NON-COMPLIANCE H-
(1) Tritium and Strontium-90 must be measured individually because
the gross beta scan analytical technique does not measure
these radionuclides.
Figure 2-5. Flow Chart for Gross Beta Particle Activity Monitoring for a
Water Source not Designated as Being Contaminated by Effluents
From Nuclear Facilities Serving More than 100,000 Persons as
Designated by the State. (U.S. EPA Las Vegas, Environmental
Monitoring and Support Laboratory)
11-16
-------
DETERMINED QUARTERLY
FROM THREE MONTHLY
SAMPLES OR THEIR
COMPOSITE
1
DETERMINED QUARTERLY
FROM THE COMPOSITE
OF FIVE CONSECUTIVE
DAILY SAMPLES
MEASURE
IGROSS BETA
IS BETA
>50pCI/l
|No| IS BETA I
O.>'5.PCI/I I
IS I-131
fa*
•"*
..
*
ANALYZE
TO IDENTIFY
RADIONUCLIDES,
DETERMINE
COMPLIANCE
WITH 141.16
1
*
ANNUAL
DOSE FROM
RADIONUCLIDES
FOUND
IS
> 4 mrtm/yr
COMPLIANCE
I NON-
I COMPLIANCE
No
«— 1
1,
-U£.
I*
J *YN
ANALYZE
FOR
Sr-89,Cs 134
i
ISSr-89 1
> BOpCI/l ]
-1
IS Cs-134 1
> 80pCI/l J
i
ANNUAL
DOSE FROM
Sr-89— C»-I34
^
-
lii
Y
| > SpCI/lj |
(COMPLIANCE K!
J NON- I
*| COMPLIANCE!
DETERMINED ANNUALLY
USING ONE QUARTERLY
SAMPLE OR THE
COMPOSITE OF FOUR
QUARTERLY SAMPLES
MEASURE
TRITIUM
AND Sr-90l
No
ANNUAL
DOSE FROM
Sr-90 H-3
>4fnrem/yr
Figure 2-6. Flow Chart for Monitoring Drinking Water Samples
Near a Nuclear Facility (U.S. EPA, Las Vegas,
Environmental Monitoring and Support Laboratory)
11-17
-------
to determine which radionuclides
are present. This must be done
to estimate the total dose since
it is different for each radionu-
clide. The doses resulting from
all these radionuclides cannot
exceed 4 mrem/yr. The concentra-
tions of the more important
isotopes that result in a dose of
4 mrem/yr are listed in
Appendix B.
As an example calculation, sup-
pose that the results of analyses
were Sr-90 = 2 pCi/1, Cs-137 =
50 pCi/1, Ba-131 = 60 pCi/1, and
1-131 - 1 pCi/1. Then, the
resulting doses can be calculated
using the Appendix, (as shown in
Table 2-4). Table 2-4 shows the
source would be in compliance
since the total dose is less than
4 mrem/yr.
If a water supply is not in
compliance with any part of the
regulations, the State and the
public must be notified. The
State is to be notified of moni-
toring results 10 days following
the end of the month in which the
measurement was made unless the
source is not in compliance, in
which case notification must be
made to the State within 48 hours.
Figure 2-6 shows the procedure
for monitoring of water supply
systems located near nuclear
facilities. For such systems
near nuclear facilities, 1-131
activity must be determined
quarterly using the composite of
5 consecutive daily samples. The
gross beta particle must be
determined quarterly from three
monthly samples or their com-
posite. Annual monitoring for
Sr-90 and H-3 is to be conducted
using one of the quarterly samples
or their composite.
If the gross beta particle activity
exceeds 15 pCi/1 for a water
supply system near a nuclear
facility, then Sr-89 and Cs-134
activities are sampled to assure
that the sum of their resulting
doses does not exceed 4 mrem/yr.
These isotopes indicate recent
contamination, such as from a
nuclear facility, since they have
short half-lives, and are not
usually present in fallout.
Where gross beta particle activity
exceeds 50 pCi/1, individual
radionuclides must be determined
using the same summing procedure
as above, to determine compliance
with the 4 mrem/yr MCL.
Analytical Methods for Measuring
Radionuclides
Sampling and analytical methods
for radionuclides are listed in
the Appendix. All methods re-
quire specialized and expensive
equipment. The small water
utility operator should consult
with a certified state or private
laboratory for assistance in
conducting the monitoring required
by the NIPDWR.
II-18
-------
TABLE 2-4
EXAMPLE CALCULATION OP TOTAL DOSE FOR
MAN-MADE RADIONUCLIDES
(1)
90
Sr
137
Cs
131
Ba
13L
(2)
Concentration
Isotope (pCi/1)
2
50
60
1
(3)
Concentration
in pCi/1 Yielding
a Dose of 4 mrem/yr
(From Appendix III)
8
200
600
3
(4)
Resulting
Individual
Dose (mrem/yr)*
1.0
1.0
0.4
1.3
3.7
TOTAL
* Method for determining resulting individual dose:
General formula:
Actual Concentration pCi/1 (2) 4.0 mrem Resulting individual
Concentration yielding dose of yr
4 mrem/yr (3)
Example calculation for Sr-90:
2 pCi/1 4.0 mrem _ 1.0 mrem
8 pCi/1 x yr yr
dose mrem/yr (4)
11-19
-------
III. NONTREATMENT AND TREATMENT ALTERNATIVES FOR
REDUCING RADIONUCLIDE CONTAMINATION IN DRINKING WATER
If it has been determined that
the concentration of radionu-
clides in the water supply ex-
ceeds allowable levels, two
methods of solving this problem
exist:
o Nontreatment alternatives
o Treatment alternatives,
i.e., for radionuclide
removal
Each is discussed in this section.
Engineering and economic data
which further aid in the analysis
of treatment and nontreatment
alternatives are given in Sec-
tions IV and VI, respectively.
Treatment data and design infor-
mation in this manual are pre-
sented for the naturally occurring
radionuclides, radium and uranium.
As explained in Section II, the
Introduction to this manual, the
potential sources of man-made
radionuclides are radioactive
fallout and accidental release
from nuclear facilities. The
MCLs for strontium-90 and tritium,
the major radionuclides from
fallout which enter water supplies,
are well above concentrations
currently detected in U. S. water
supplies. There is scant infor-
mation available on the removal
of these, or other man-made
radionuclides from drinking water
supplies. The MCLs for radionu-
clides do not apply to one-time
situations such as might follow a
major contaminating event. In
such situations, Federal guidance
as published in the Federal
Register Notices of August 22,
1964 and May 22, 1965 will apply.
The emergency plans of the States,
as provided for in Section 1413(A)(5)
of the Safe Drinking Water Act,
should follow the Federal guidance.
For those utilities interested in
disaster planning, the Suggested
Reading list in this manual
contains several references for
the emergency treatment of water
supplies which have been contami-
nated by fallout or radionuclide
release due to a major contami-
nating event.
NONTREATMENT ALTERNATIVES
Four options are covered in this
category:
o Raw water source substitution
o Blending with water low in
radionculides
o Connection to an existing
regional system
o Organizing a regional system
Inherent in all of these options
is the usually correct assumption
that the radionuclide problem is
localized. Thus, it may be
possible to find acceptable water
from other nearby wells or sur-
face sources. Also, an existing
well might be modified to draw
water from different aquifers
(water bearing levels). Surface
water users may find it feasible
to draw from other streams, or
may find that relocation of the
intake will solve the problem.
Substitution of sources should
receive top priority in the
search for solutions. Since the
MCLs for radionuclides apply to
the water as it is delivered to
the user, raw water which ex-
ceeds the standards may be used
III-l
-------
if it is blended with other
supplies sufficiently low in
contamination such that the
resulting water meets the stan-
dards. For example, a water
supply could be made up of equal
quantities of two raw supplies
containing 2 pCi/1 and 8 pCi/1 of
radium, respectively, and still
meet the 5 pCi/1 standard for
combined Radium 226 and 228.
It may also be cost effective to
obtain all or at least a suffi-
cient amount of water for blending
from an outside supplier, perhaps
a nearby city or regional system.
Regional systems are becoming
more attractive as their advan-
tages become increasingly apparent.
Larger systems can spread the
costs of water quality monitoring
and analysis, as well as opera-
tion and maintenance, over a
larger user base, thereby lower-
ing per capita costs. The anal-
ysis of nontreatment alternatives
is not complete without investi-
gating regionalization alterna-
tives. Joining an existing
regional system, or forming a new
regional utility by joining with
other nearby systems which may be
having similar water quality
problems should be considered.
A broad range of regionalization
alternatives is explained in the
following reference:
Regionalization Options for
Small Water Systems U. S. EPA
Office of Drinking Water, 401 M
Street, SW, Washington,
DC 20460.
TREATING WATER SUPPLIES FOR
RADIUM AND URANIUM REMOVAL
The concentration of radium in a
drinking water supply can be
reduced by any of the following
treatment techniques:
o Lime or Lime-Soda Softening
o Ion Exchange Softening
o Reverse Osmosis
Uranium may be removed by either
of the following treatment
techniques:
o Anion (negatively charged
ion) Exchange, or
o Reverse Osmosis
The applicability of these treat-
ment techniques is summarized in
Table 3-1. Considerable data are
available about the treatment
techniques listed for radium
removal, including substantial
data from full-scale operating
plants. Much less information is
available on the removal of
uranium; however, recent laboratory-
scale studies provide sufficient
information to allow the prelimi-
nary selection of a treatment
system for uranium removal. It
is essential that prior to design
and construction of a treatment
system for uranium, a utility
with elevated uranium levels in
its drinking water conduct labora-
tory or pilot-scale tests on the
specific raw water to be treated.
Pilot-scale studies are also
recommended prior to final design
of a system for radium removal,
in order to ensure that the
treatment system will achieve
acceptable performance.
The softening methods are effective
because radium is chemically
similar to calcium and magnesium,
the primary components of hard
water. Reverse osmosis, a membrane
technology used for desalting sea
water or brackish water, is
effective because it provides for
III-2
-------
TABLE 3-1
TREATMENT TECHNIQUES APPLICABLE FOR REDUCING
RADIUM AND URANIUM RADIONUCLIDES FROM DRINKING WATER
Treatment
Technique
Radionuclide
Removed
Approximate
Range of
Reduction
Percent
Comments
Lime or
Lime-Soda
Softening
Radium
56-94 Considerable full-scale
system data available
Uranium
85-98 Requires pH above 10. 6.
Limited lab-scale data
data available
Ion
Exchange
Radium
Uranium
90
90
Considerable full-scale
system data available
Cation exchange process
Limited lab-scale data
available
Anion exchange process
High resin capacities
reported
Selective Radium
Complexer
Unknown Experimental technology
currently being field
tested by Dow Chemical
Reverse
Osmosis
Uranium
Radium
N/A
90
N/A
Limited full-scale data
available
Uranium
90
Limited lab-scale data
available
Coagulation Radium
and
Filtration
Minimal Not applicable for radium
removal
Uranium
5-90 Limited lab-scale data
available
Uranium removals highly
variable and dependent on
pH and other water qual-
ity parameters
High pH may be required for
maximum removals, which
is generally uncommon
practice in coagulation
IH-3
-------
high levels of removal of nearly
all dissolved ions in water,
which would include radium.
Conventional treatment methods
such as coagulation, settling,
filtration, or chlorlnation, have
little or no capability to remove
radium from drinking water.
Coagulation using aluminum sulfate
(alum) or lime/lime-soda softening
have been shown in tests conducted
by the Oak Ridge National Labora-
tory (ORNL) for EPA to be capable
of reducing uranium concentrations
under certain very specific
conditions. These conditions
include a pH of greater than
10.6 and the presence of rela-
tively high magnesium and alka-
linity concentrations. Although
these conditions may exist in
some lime or lime-soda softening
plants, they are very uncommon in
conventional coagulation applica-
tions. A survey conducted by
ORNL for EPA of several existing
coagulation and lime-soda softening
plants throughout the United
States in locations with elevated
uranium concentrations demonstrated
little or no uranium reduction.
Although these plants were not
being operated to achieve uranium
reduction, the survey results of
full-scale plants indicate that
insufficient data are available
to recommend conventional coagula-
tion an filtration or lime/lime-
soda softening for uranium removal,
particularly if new construction
is required.
A utility which must remove
uranium and which currently
treats its water using alum
coagulation or lime softening
might consider modification of
its existing facilities to im-
prove uranium removal. An expert
water treatment consultant or
engineer experienced in radionu-
cllde removal should provide
advice on such modifications.
Optimization of alum coagulation
or lime softening for uranium
removal is very site-specific and
requires complicated laboratory
or pilot-scale testing which is
beyond the scope of this manual.
Ion exchange can be used for
uranium removal from drinking
water when the proper anionic
exchange medium is used because
uranium is present in most natural
waters as an anion (uranyl anion).
Reverse osmosis is effective
because it provides for high
levels of removal of nearly all
dissolved ions in water, includ-
ing the uranyl ion.
Lime and Lime-Soda Softening
The hardness of most water sup-
plies is caused by the presence
of calcium and magnesium ions in
solution. One method of softening
water involves changing the
calcium and magnesium compounds
dissolved in water to an insoluble
form, and then removing the
insoluble compounds (precipitates)
by sedimentation and filtration.
This process is known as the
chemical, or lime-soda softening
process, since lime in the form
of calcium oxide (quicklime) or
calcium hydroxide (slaked or
hydrated lime) is the most common
chemical used to precipitate the
hardness from drinking water.
Radium, which is chemically
similar to calcium and magnesium,
is also precipitated and removed
from water during the lime-soda
process.
III-4
-------
Process Description
Figure 3-1 shows a simplified
schematic of the lime-soda soften-
ing process. It contains the
following steps:
o Chemical feeding and mixing,
o Flocculation,
o Sedimentation,
o Recarbonation, and
o Filtration
During chemical feeding and
mixing, lime, soda-ash, or caustic-
soda are added to the raw water
and rapidly mixed to ensure quick
solution of all chemicals.
During this operation, the pH of
the raw water is raised and the
chemical reactions which will
remove some of the hardness and
radium from the water begin.
During flocculation, the raw
water is gently mixed. The
purpose of this mixing is to
assist the chemical reactions
which cause the precipitation of
insoluble calcium, magnesium, and
radium compounds. It is not
necessary to know the details of
the many chemical reactions which
take place in order to understand
the basic lime-soda softening
process. The Bibliography con-
tains several references which
explain in detail the chemistry
involved. In order to illustrate
the type of reactions which occur
during the process, two represent-
ative reactions involving calcium
are discussed.
Calcium ions (hardness) dissolved
in water most often take |lje form
of calcium bicarbonate Ca (HCO ~),
This is known as carbonate hardnes^
When lime is added to the water,
the following reaction takes
place:
Calcium
Lime Bicarbonate
Ca (OH)~ + Ca(HC03)2 -
•
Calcium
Carbonate Water
2CaCO I + 2H 0
The calcium carbonate formed in
the reaction is a solid and
precipitates, thereby removing
both the original calcium ion
which existed in the raw water
and the calcium ion added with
the lime.
If there is not enough alkalinity
present in the raw water, some of
the hardness is present as noncar-
bonate hardness. Soda ash (Na CO )
must then be added in order that
the solid calcium carbonate can
be formed. This is why the
process is referred to as the
lime-soda process.
Magnesium and radium ions enter
into similar reactions with lime
and soda ash and form similar
solid compounds. More lime must
be added to remove magnesium than
calcium because magnesium carbonate
is a soluble compound and magnesium
is precipitated as magnesium
hydroxide, Mg(OH) . Any free
carbon dioxide in the raw water
will also react with the lime
added and increase the lime
requirements for softening.
Chemical requirements for soften-
ing are presented in Section V.
Once the chemical reactions are
complete, the precipitated solid
compounds are removed from the
water by sedimentation. It is
usually easy to settle lime-soda
softening precipitates because
they are much denser than water.
Since the pH of a lime softened
water is generally in the range
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of 8.5-11, the pH often must be
readjusted to a lower value in
order to prevent formation of a
scale in the water distribution
pipes. Sometimes the normal
chlorination of the water for
disinfection purposes will suf-
ficiently lower the pH. Often,
however, carbon dioxide must be
added to the water following
sedimentation in order to lower
the pH. This operation, called
recarbonation, may be accomp-
lished by bubbling C02 gas through
the water in a separate, small
reaction basin.
Sometimes the chlorine added to
the water for disinfection may
decrease the pH to a stable value
so that recarbonation is not
necessary. Another alternative
to stabilizing a lime softened
water would be the addition of a
commercial acid such as HC1 or
H-SO, (hydrochloric or sulfuric
acid, respectively).
The final operation in lime-soda
softening is filtration. Filtra-
tion is a polishing step required
to remove any unsettled solids
from the water, thus providing a
water which meets the turbidity
regulation. Pressure filters are
sometimes used for small systems.
Larger systems use gravity-type
rapid sand filters. A very
common filter used for small
lime-soda systems is a gravity-
type filter which backwashes
(cleans) itself automatically
using a hydraulic arrangement.
A more detailed discussion of
filtration methods, as well as
detailed design procedures for
filtration can be found in an
EPA document titled Turbidity
Removal for Small Public Water
Systems.
Lime-Soda Softening Equipment
Most lime-soda softening plants,
and nearly all small plants,
utilize equipment which combines
the necessary operations in one
unit. Figures 3-2 and 3-3 show
diagrams of the two typical types
of lime-soda softening plants
used for small water systems.
Upflow or solids contact units,
shown in Figure 3-2, combine
chemical mixing, flocculation,
and sedimentation in one physical
unit. Upflow, catalytic softening
units, as shown in Figure 3-3,
have the advantage of generating
a sludge which consists of hard,
pellet-like beads which dewater
rapidly and which are relatively
easy to handle and dispose. Both
types of softening units require
filtration to polish the softened
water.
Table 3-2 presents a partial list
of equipment suppliers who provide
lime-soda softening equipment.
Radium Removal by Lime-Soda
Sof tening
Radium removal by lime softening
can be related to hardness removal
(Figure 3-4) and pH of treatment
(Figure 3-5). The higher the pH
of treatment, up to a pH of
about 11, the greater the amount
of hardness and consequently the
greater the amount of radium
removed.
The removal curves presented in
Figures 3-4 and 3-5 are empirical
and are based on data from full-
scale lime or lime-soda softening
plants in Iowa, Illinois, and
Florida. All of these plants
were being operated to produce a
desired level of hardness in the
finished water, not to optimize
III-7
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a
a)
4J
§
u
CM
CO
a)
w
QJ
O
O
tfi
111-8
-------
AIR VENT
TEST
COCKS
CHEMICAL
INLETS
DRAW-OFF
VALVE FOR
ENLARGED
CATALYST
«•— SOFTENED
WATER OUTLET
CHEMICAL
INLETS
RAW WATER
INLET
RAW WATER
INLET
Figure 3-3. Typical Upflow, Catalytic Lime Softening Unit
III-9
-------
9 i.oo
o
H
0.80
>
0)
co 0.60
0)
c
0.40
0.20
O Elgin, IL, water at EPA pilot plant
• West Des Moines, IA
jfc Webster City, IA, without soda ash
* Webster City, IA, with soda ash
X Peru, IL, three dates
$ Elgin, IL, three dates
£± Englewood, FL
A Venice, FL
0.20 0.40 0.60 0.80
Radium Removal Fraction
l.OO
Source: EPA Publication 600/8-77-005, Manual of Treatment Techniques
for Meeting the Interim Primary Drinking Water Regulations.
Figure 3-4. Lime-Soda Process, Total Hardness Removal Fraction
Versus Radium Removal Fraction
111-10
-------
1.00
c
o
S 0.80
n)
M
fa
0.60
9
=3
°'40
0.20
O Elgin, IL, water at EPA pilot plant
• West Des Moines, IA
jHf, Webster City, IA, without soda ash
^|C Webster City, IA, with soda ash
X Peru, IL, three dates
A Englewood, FL
A Venice, FL
I
I
i
9 10
pH of Treatment
Source: EPA Publication 600/8-77-005, Manual of Treatment Techniques
for Meeting the Interim Primary Drinking Water Regulations.
Figure 3-5. Radium Removal Fraction Versus pH of Treatment,
Lime-Soda Process
III-ll
-------
TABLE 3-2
LIME-SODA SOFTENING EQUIPMENT SUPPLIERS
Company
Location
Envirex, Inc.
General Filter Co.
Hungerford & Terry, Inc.
Permutit Co.
Inf ilco-Degremont
Dorr-Oliver
Roberts Filter Mfg. Co.
Neptune Microf loc
Clow Corp.
Western Precip
Division of Joy Mfg. Co.
Waukesha, Wisconsin
Ames, Iowa
Clayton, New Jersey
Paramus, New Jersey
Richmond, Virginia
Stamford, Connecticut
Darby, PA
Corvallis, Oregon
Oak Brook, Illinois
Los Angeles, California
radium removal. The use of these
curves to obtain a desired level
of radium removal should be
considered approximate, as consid-
erable variation exists in the
data used to derive the curves.
This variation should pose no
major problem during design,
however, since hardness (and thus
radium removal) can be easily
regulated within previously
stated limits by varying the
amount of lime and/or soda ash
added to the process units, which
are sized based primarily on
hydraulic considerations.
Lime or lime-soda softening is
most applicable to waters of
moderate to high total hardness
(about 120 to 400 mg/1 of TH as
CaCO ) where total dissolved
solids is about 750 mg/1 or less.
When the raw water source is
harder than about 400 mg/1,
chemical requirements may be
prohibitive. When TDS is about
750 mg/1, the finished water TDS
may exceed the 500 mg/1 secondary
standard. Although it may be
possible to reduce radium from a
low hardness water using lime or
lime-soda softening, site-specific
data are not available and,
therefore, such an application is
not currently recommended.
Ill-12
-------
Advantages and Disadvantages of
Lime-Soda Softening for Radium
Removal
The advantages of lime-soda
softening are:
1. It produces an excellent
quality water, and is easily
capable of reducing radium
to within the 5 pCi/1 MCL
from source waters contain-
ing up to 25 pCi/1.
2. Finished water is easily
stabilized to protect the
distribution system.
3. Capital costs are competi-
tive with ion exchange and
reverse osmosis.
4. Trace metals, as well as
radium, are removed in the
process. In addition, the
concentration of total
dissolved solids is reduced
and depending on initial
alkalinity, no incease in
sodium may be necessary.
The disadvantages of lime-soda
softening are:
1. Operating costs are high,
particularly chemical costs,
as compared to ion exchange.
2. Requires significant opera-
tional attention.
3. Process is more difficult to
control than ion exchange or
reverse osmosis.
4. The process is currently
limited, for reasons of
practicality and equipment
availability, to systems of
75,000 gpd or more.
5. The waste sludge may be
difficult to dispose of.
Ion Exchange Treatment
Ion exchange treatment does
exactly as the name implies: it
trades one type of ion for another.
The exchange process can be
tailored to remove cations (posi-
tively-charged ions), by cation
exchange, or to remove anions
(negatively charged ions), by
anion exchange.
Radium, present in water supplies
as a cation is removed by the
cation exchange process, which is
also called ion exchange or
zeolite softening. Uranium,
probably present in water as an
anion, has been shown in labora-
tory experiments to be removed by
the anion exchange process. Both
processes work by exchanging the
ion of interest (radium, calcium,
and magnesium cations; or uranium
anions) with a similarly charged
ion on the surface of a solid
medium called an ion exchange
resin. Both processes are revers-
ible, which means the used resin
can be regenerated and thus
prepared for further exchange
cycles. Except for the type of
resin used, and perhaps the
regenerant chemical, cation and
anion exchange systems utilize
the same equipment and operational
procedures. Since considerable
data are available on cation
exchange systems for radium
removal, and only very limited
data on anion exchange systems
for uranium removal exist, the
discussion on ion exchange will
focus primarily on cation exchange
for radium removal. Anion exchange
for uranium removal will also be
addressed, but in a more limited
fashion since its application to
water treatment is currently
still in the experimental stage.
111-13
-------
Ion Exchange Softening (Cation-
Exchange)
In the ion-exchange softening
process, the hardness causing
calcium and magnesium cations are
removed by exchange with a cation
such as sodium or hydrogen which
does not impart hardness to a
water. This exchange takes place
on the surface of the ion exchange
resin through which the water is
passed. Radium, being a divalent
cation (+2 electrical charge)
similar to calcium and magnesium,
is also removed from water by ion
exchange softening.
Ion exchange is a reversible
process. Once the exchange resin
is exhausted (can remove no more
hardness ions), it can be regen-
erated by soaking the resin in a
strong solution of sodium chloride
(salt), which returns the resin
to its original condition, ready
for further cycles.
An acid solution may also be used
as a regenerant if it is desirable
to limit the amount of sodium
added to the raw water in the
exchange process. If an acid
regenerant is used, the system is
said to be operating in the
hydrogen cycle. When salt is
used as the regenerant, the
system is said to be operating in
the sodium cycle. Although
hydrogen cycle operation, due to
the requirements for handling and
disposing of relatively concen-
trated acid streams, has been
unpopular for application by
small water utilities, its use
may be desirable to eliminate the
addition of sodium in certain
systems.
Originally, media used for ion
exchange softening came from
natural sources such as greensand
(glauconite) found in various
parts of the world; the largest
principal commercial deposit
being in New Jersey. The term
"zeolite" has been loosely applied
to all those materials which are
used for ion exchange softening,
including greensand, bentonitic
clay, synthetic gel-type material,
sulfonated coal, and the synthetic
organic resins. Strictly speaking,
the term zeolite should include
only those organic aluminosilicates
which display ion exchange
properties.
Most of the ion exchange resin
used today, cationic and atiionic,
are manufactured materials which
are resistant to attack over a
wide pH range and are physically
strong enough that they do not
break up during use. Ion exchange
resins are tiny spherical beads
about the size of medium sand.
The beads are uniform in size and
color. Each bead is, in effect,
a skeleton on which numerous
exchange sites are available. A
partial list of the manufacturers
of ion exchange resin are listed
in Table 3-3.
How Ion Exchange Softening Works
Figure 3-6 is a schematic of a
typical ion-exchange system. An
ion-exchange cycle consists of:
softening - exhaustion - regenera-
tion - backwash. When an ion
exchanger is placed in service,
either initially or following
regeneration, sodium ions are
present on the exchange resin.
As hard water is passed through
the exchanger, the hardness-
causing ions, including radium,
are replaced in the water by the
sodium ions from the resin and
the hardness-causing ions replace
the sodium ions on the resin. A
111-14
-------
METER
•CO
-fs^l
ION-EXCHANG
UNIT x_
EXCHANGE
MATERIAL^
^
T?_i
. .WASH WATER
N
.jf
=j
' COLLECTOR
PRESSURE
WATER — 2
CDUCTOR
OUTLET
H VALVE CLOSED
r><] VALVE OPEN
SUPPORTING
TO BED
WASTE
RE GENERA NT
TANK
>-4«. Bl«tr» of Iyplc.1 Ioo-t.ch.ti,. Onlt - Softnlnc MoJ*
ri«u» V4e. ti*ftm of
Ioo-beliat« Unit -
VALVE CLOSED
JX] VALVE OPEN
I TO
I WASTE
TANK
OUTLET
^4 VALVE CLOSED
[X] VALVE OPEN
SUPPORTING
TO mrn
WASTE
l-*b. tUjrm of Typlul Ian-txchu>|« Dnlt - tetnmtlon
tlfirt >-M. M*|rn of
Ion-Z>ch«nt< Volt -
Figure 3-6. Operation Modes in a Typical Ion-Exchange Unit
111-15
-------
TABLE 3-3
PARTIAL LIST OF U. S. ION EXCHANGE RESIN PRODUCERS
Company
Location
Trademark
Diamond Shammock
Dow Chemical Company
Sybron Chemical Company
lonac Division
Rohm and Haas Company
Cleveland, Ohio
Midland, Michigan
Duolite
Dowex
Birmingham, New Jersey lonac
Philadelphia, Pennsylvania Amberlite
general equation for the ion-
exchange softening process step
is:
Softening
Ca + 2NaR
2Na
where R represents the ion-exchange
resin. This expression shows
that two monovalent sodium cations
are now in solution rather than
one divalent cation such as
calcium or radium. Because of
the exchange of two sodiums (with
a total weight of 46) for one
calcium (with a weight of 40) the
total dissolved solids of the
water increases. (For magnesium
the exchange is 46 for 24.)
Calcium is now attached to the
ion exchange resin in place of
two sodiums.
Hardness and radium removal may
approach 95-100%. The actual
removal, however, will depend on
how long the resin has been in
sevice between regenerations, the
surface loading rate, the contact
time of water with the resin, and
the condition of the resin.
Resins can be fouled by buildup
of suspended solids not removed
during backwashing, by biological
growth in the resin bed, and by
concentrations of iron (2 to
3 mg/1) in the raw water. Al-
though iron is easily removed
from solution by the resin, it is
not easily removed from the resin
by regeneration. Pretreatment in
the form of aeration and/or
filtration can minimize fouling
problems associated with solids
and iron. The preapplication of
disinfectants can minimize bed
fouling by biological growth,
although care must be taken not
to indiscriminately use disinfec-
tants such as chlorine which may
damage some ion-exchange resins,
or increase the formation of
total trihalomethanes.
As hard water continues to pass
through the exchanger and sodium
ions are replaced by the hardness-
causing ions, a point is reached
when the exchanger is exhausted.
Exhaustion means that the amount
of hardness-causing ions exchanged
for sodium has decreased beyond
111-16
-------
an acceptable point and the
effluent is "harder" than desired.
This is also sometimes called
"break-through."
Fortunately for the waterplant
operator, radium is held on the
resin after the resin bed has
been exhausted for hardness
removal. This occurs because
when the bed is saturated with
calcium or magnesium ions, most
cation-exchange resins will
preferentially exchange a radium
ion for a calcium or magnesium
ion. Thus, a water plant operator
can safely operate an ion-exchange
softener until hardness "breaks
through" the bed before regenera-
tion, and any radium in the raw
water will continue to be removed
by the resin. This removal of
radium following hardness exhaus-
tion will not continue indefinite-
ly, however. Once hardness
break-through has occurred, the
operator should start the regen-
eration step of the resin bed as
soon as possible. Regeneration
of an ion-exchange softener means
replacing the hardness-causing
ions on the resin with sodium
ions, such as shown by the fol-
lowing reaction:
Regeneration
CaR + 2Na
++
2NaR
The regeneration step differs
from the softening step in that
the concentration of sodium ions
in the regenerant is many times
greater than the concentration of
hardness-causing ions present in
the untreated water. Therefore,
the volume of regenerant solution,
such as a concentrated salt
solution or brine, is only a
fraction of the total water
volume processed in the softening
step. As a result, the concentra-
tion of the hardness-causing ions
is many times greater in the
waste regenerant than in the
untreated water.
As shown in Figure 3-6, highly
concentrated regenerant (salt)
from a storage tank is diluted
with untreated water to the
concentration recommended by the
resin manufacturer. The diluted
regenerant is then pumped through
the resin bed in the same direc-
tion as was the water during the
softening step. This is done for
two reasons: 1) the more exhausted
resin is at the top of the bed
where contact is first made with
the untreated water, and 2) the
regenerant solution can drain
from the resin bed reducing the
volume of backwash water needed
to flush the bed. A lateral type
distributor is used to spread
regenerant over the resin surface.
The volume of regenerant solution
needed will depend on the specific
resin, concentration of regenerant
solution and the volume of ion-
exchange resin. Generally,
manufacturers will specify the
pounds of sodium chloride to be
used per cubic foot of resin.
Typically, a 10 percent brine
solution is used as the diluted
regenerant. The regeneration
cycle time will depend on the
volume of regenerant required and
the loading rate specified by the
manufacturer.
Following regeneration, the
excess brine and solids entrapped
in the resin bed must be flushed
out. This is accomplished during
backwash of the resin bed.
During backwash, treated water is
applied in an upflow direction at
a rate sufficient to gently
separate the individual resin
beads. This expansion allows
suspended materials to be flushed
111-17
-------
from the bed and prepares the bed
for further operation by minimizing
"channeling" or inconsistent flow
through the bed during operation.
The length of the backwash cycle
is specified by the manufacturer,
but may be changed, if necessary.
In most cases, this will depend
more on requirements for solids
removal than on flushing of the
brine.
Once the backwash cycle is complete,
the ion-exchange column can be
placed back into service beginning
the softening process again, and
therefore removal of radionuclides.
With experience, the ion-exchange
operating cycle can be placed on
a time sequence. That is, the
length of time between regenera-
tions, the regeneration cycle
time and the backwash cycle
length can all be pre-set based
on historical performance.
Occasional adjustment of the time
cycle may be required as the
resin ages or if the raw water
quality changes.
The waste regenerant brine and
the backwash water both require
disposal. The waste brine is a
disposal problem due more to its
brine content than to the small
amount of radium it contains.
Disposal options and requirements
are discussed in Section V.
Ion Exchange Equipment
An ion-exchange treatment unit
consists of a tank or vessel
which contains the ion-exchange
resin, along with associated
valves, pumps, piping, and con-
trols. A storage tank for regen-
erant salt and a vessel for
mixing of regenerant brine solu-
tions are also part of a complete
treatment unit.
The treatment vessel may be the
pressure-type device or the open
gravity type. Most small treat-
ment systems use a pressure-type
vessel similar to the one depicted
in Figure 3-7. A typical pressure
unit generally consists of a
closed steel cylinder which may
be placed vertically or horizon-
tally. In designing such tanks
the diameter must be limited to
less than 12 feet because of
overland shipping restrictions.
Gravity or open top softeners
usually are built of concrete and
are rectangular in shape, although
some round steel gravity units
have been built. The pressure-
type has one advantage over the
open-type in that it is possible
to pump water to the unit directly
from the source of supply, through
the unit and directly into the
distribution system without
repumping. Gravity filters also
have advantages. Since they are
open top, it is possible to see
what is happening inside and,
therefore, identify any problems
such as channeling. Also, during
the backwash cycle, loss of resin
can be seen and corrected.
Suppliers of Ion-Exchange Systems
There are many suppliers of
ion-exchange equipment packages.
Table 3-4 is a partial list of
these manufacturers.
Most of these manufacturers
provide package systems or com-
ponents within the size range of
the small water supply. Most
also provide bench scale testing
and full design capabilities.
111-18
-------
High Rate
Inlet Diffuser
and Backwash
Collector
Access Manhole
Welded Carbon
Steel Shell
Underdrain System
Raw Water Inlet
Primary Baffle
Secondary Baffle
Freeboard
Regenerant Inlet
Repenerant
Diffuser
Ion Exchange Resin
Treated
Water Outlet
Figure 3-7. Typical Pressure-Type Ion Exchange Treatment Vessel
111-19
-------
TABLE 3-4
PARTIAL LIST OF U. S. SUPPLIERS OF ION EXCHANGE SYSTEMS
Company
Location
Culligan
Envirex
Graver
General Filter
Hungerford & Terry Inc.
Illinois Water Treatment
Infilco-Degremont
Ionics
Permutit
Northbrook, Illinois
Waukesha, Wisconsin
Houston, Texas
Ames, Iowa
Clayton, New Jersey
Rockford, Illinois
Richmond, Virginia
Watertown, Massachusetts
Paramus, New Jersey
Radionuclide Removal by Ion
Exchange
Radium removal by ion-exchange
softening is related to hardness
removal. Well-operated ion-
exchange plants can remove as
much as 95 percent or more of the
radium in raw water (Figure 3-8)
prior to blending. Because
radium removal still takes place
for a period of time after the
resin ceases to remove hardness,
regeneration to achieve good
hardness removal will assure good
radium removal.
Most water plants which use
ion-exchange softening blend a
portion of the raw water with the
treated (nearly zero hardness)
water. This is done in order to
produce a finished water of
moderate hardness which is less
corrossive to water pipes than
water of very low hardness.
Blending also allows the treat-
ment units to be sized to treat
only a portion of the finished
water requirements, thus increas-
ing cost effectiveness.
If blending is to be done, the
raw water concentration of radium
must be taken into consideration
to ensure that the finished
water, after blending does not
exceed the 5 pCi/1 MCL.
Ion-exchange softening using
cation exchange resins is not
effective in removing uranium
from drinking water, since uran-
ium is present in most water
sources primarily as an anion
111-20
-------
1.00
e
o
2 0.80
jj 0.60
•§
0.40
I I
0.20
I I || | I I I III
I I I
0.40 0.60 0.80
Total Hardness Removal Fraction
1.00
Source: Manual of Treatment Techniques for Meeting the Interim Primary
Drinking Water Regulations, EPA 600/8-77-005, May 1977.
Figure 3-8. Radium Removal Fraction Versus Total Hardness Removal
Fraction in Ion Exchange Plants, Before Blending
111-21
-------
(uranyl carbonate). Anion ex-
change resins should be very
effective for selective uranium
removal. Mixed bed ion exchangers
(with cation and anion exchange
resins) have been used success-
fully in some ion-exchange appli-
cations. Their potential for
radionuclide removal is uncertain
and should be evaluated on a
case-by-case basis.
Laboratory studies have shown
that a particular anion exchange
resin, Dowex 1-X2, can remove up
to 99 percent of uranium from a
natural water. These preliminary
studies also show that the resin
has the ability to hold large
quantities of uranium.
Anionic exchange systems operate
exactly the same as ion exchange
softeners. They have the same
equipment and process flow schemes.
The regenerant solution and the
type of resin are the only major
changes required. No hardness
removal would occur during anion
exchange; however, some removal
of natural water anions, such as
sulfates or carbonates, might
occur. Anionic exchange for
uranium removal from drinking
water is still in the experimental
stage. Considerable pilot-scale
testing would be required before
a utility could use such a system.
Advantages and Disadvantages of
Ion-Exchange Sofening for Radio-
nuclide Removal
The advantages of ion-exchange
softening for radionuclide remov-
al are:
1. Ease of operation and con-
trol; many ion-exchange
plants are completely auto-
mated, reducing need for
labor;
2. Finished water hardness and
radionuclide content can be
closely controlled by blending
treated water with raw water
in varying amounts;
3. Costs can be held quite low
for small plants;
4. Treated water alkalinity is
not affected by sodium cycle
operation; and
5. Trace amounts of heavy
metals, as well as radio-
nuclides, are often easily
removed.
Some disadvantages of the ion-
exchange process for radionuclide
removal are:
1. Finished water shows an
actual increase in total
dissolved solids since one
calcium ion of atomic
weight 40 is replaced by two
sodium ions of total atomic
weight 46; Hydrogen cycle
operation eliminates this
disadvantage, however fin-
ished water alkalinity is
decreased;
2. Sodium concentrations may be
elevated above concentrations
allowed for people on sodium
restricted diets. In addi-
tion, elevated sodium levels
may be associated with
increased incidence of
hypertension and cardiovas-
cular diseases. Hydrogen
cycle operation eliminates
this disadvantage, however
finished water alkalinity is
decreased and operational
control is more difficult;
3. Raw water requires pretreat-
ment if turbidity and sus-
pended solids, iron and
manganese, or bacterial
slimes are present;
111-22
-------
4. Finished water may be cor-
rosive in distribution lines
unless some form of stabili-
zation is practiced;
5. Disposal of spent brines can
be a difficult problem.
Regulatory agency approval
is often difficult to obtain.
Brine disposal is discussed
in more detail in Section V.
Reverse Osmosis
Reverse osmosis (RO) is a membrane
treatment process capable of
demineralizing water. Water
which has passed through an RO
membrane is low in inorganic and
organic constituents, essentially
free of suspended matter, bacteria
and virus. Radium, uranium, and
most manmade radionuclides can be
removed by RO. Radium and uranium
removals by RO systems generally
exceed 95 percent.
Because RO is generally an expen-
sive treatment technique, it is
usually applied for treatment of
brackish water or sea water.
Process Description
Osmosis is a property of solutions
defined as the spontaneous flow
of water into a solution. When
both diluted and concentrated
solutions are separated by a
porous membrane, osmosis occurs
as the dilute solution passes
through the membrane into the
concentrated solution (Figure 3-9a).
If the membrane which separates
the solutions is selective in
that the solvent (pure water) can
pass through the membrane while
dissolved material in the solu-
tion cannot, the membrane is said
to be "semipermeable." The
osmotic pressure is that pressure
which must be used to prevent the
passage of pure water through a
membrane which separates the
solution and the water.
By applying pressure greater than
the osmotic pressure to the more
concentrated solution of a semi-
permeable membrane, pure water
can pass through the membrane
while the dissolved materials
cannot (Figure 3-9b). This
process, known as reverse osmosis,
is very effective in separating
divalent or trivalent ions,
including the radionuclides
radium and uranium, from water.
RO processes are governed by two
basic principles, the flow of
water through the membrane depends
on the pressure applied and the
movement of the dissolved material
is dependent upon the concentra-
tion differences in the feed
water and product water.
The difference between the applied
pressure and the osmotic pressure
of the solution determines the
flow of water through the membrane.
The difference in concentration
between the feed water and the
product water determines the rate
of ion movement toward the mem-
brane. These factors vary for
different membranes and the way
they are placed in RO modules.
Types of Membrane Systems
There are two major membrane
configurations: the spiral-wound
module (Figure 3-10) and the
hollow fiber (Figure 3-11). The
spiral-wound membrane has one or
more membrane envelopes each with
a porous material between two
large, flat membrane sheets. The
membrane envelope is sealed on
three edges with a special ad-
111-23
-------
Concentrated
Solution
Semipermeable
Membrane
i
Fresh Water
Figure 3-9a. Osmosis - Normal Flow from Low-Concentration Solution
to High-Concentration Solution
Pressure
Semipermeable
Membrane
Concentrated
Solution
Fresh Water
Source: Costs of Radium Removal From Potable Water Supplies, MERL,
Cincinnati, OH, EPA-600/2-77-073.
Figure 3-9b.
Reverse Osmosis - Flow Reversed by Application of Pressure
to High-Concentration Solution
111-24
-------
Feed Water &
Brine Spacer
Desalted water
through the membranes
on both sides of the
porous product water
carrier.
Brine Concentrate
Product Water
Brine Concentrate "^3
Membrane
Porous Product Water Carrier
Membrane
" Feed Water and Brine Spacer
Feed Water
Source: Fluid Systems Division, Universal Oil Products
Figure 3-10. Cutaway View of a Spiral Membrane Element
111-25
-------
INO »»Tt
Figure 3-11. Perinea tor Assembly for Hollow Fine Fiber Membranes
111-26
-------
hesive and attached with the
adhesive to the outside of a
small diameter pipe. The pipe
has openings to collect the water
which passes through the membrane.
This product water is referred to
as the permeate. The envelopes
are wound around the pipe to form
a cylinder with diameters ranging
from 2 to 12 inches and up to
40 inches in length. The envelope
is wrapped on the outside to
prevent bursting. The inner pipe
allows for the flow of permeate
and for the connection of several
sections of membrane elements.
The entire series of membrane
elements are then housed within a
pressure vessel.
The second type of RO membrane
design is the hollow, fine fiber
membrane, which uses either a
polyamide polymer membrane made
by DuPont or a cellulose triace-
tate membrane made by Dow Chemical
Company. The polyamide fibers
have diameters between 50 to
85 microns (10 centimeters)
with the internal diameter of the
hollow fiber about one-half the
outer diameter. The cellulose
triacetate fibers have outer
diameters of 200 to 300 microns.
The membrane and pressure vessel
as shown in Figure 3-11 are
integrated units. The fibers are
formed into a V-shaped bundle,
with the open ends in an epoxy
tube sheet. The bundle attached
to the tube sheet is arranged in
a cylindrical pressure vessel.
In the hollow fiber membrane
system, feedwater is pumped to
the center of the vessel through
perforated pipe. Under pressure
the water is forced through the
hollow fibers and the permeate
flows out through the middle of
the fibers. The water and dis-
solved solids which do not pass
through the fibers continues
through the bundle and flows
through a discharge pipe. This
part is referred to as the
"reject" stream.
Both systems require large high
pressure pumps to produce pres-
sures greater than the osmotic
solution pressure and to maintain
continuous flow of permeate. The
hollow fiber design is simple to
install, but clogs more easily
than a spiral wound design. With
either membrane design, an RO
system is built of one or more
modules. The modules can be
connected in parallel with each
module receiving part of the
total flow not previously treated
by RO, or in series with the
permeate from one or more RO
modules becoming the feed to the
next module in the series.
Series operation is used when
high removals of a contaminant
are required.
Figure 3-12 depicts a simplified
schematic of a typical RO system.
Pretreatment Requirements
As with any equipment, operation
of an RO system is not problem
free, but with proper pretreatment
before the membrane, better and
more continuous performance may
be maintained. Scaling of the
membrane can be caused by the
precipitation of slighlty soluble
compounds. As the feed water
passes through the system, the
reject portion will become more
concentrated in these slightly
soluble compounds, which will
precipitate on the membrane.
Calcium carbonate (CaCO) is the
most common substance that precip-
itates. It can be controlled by
reducing the pH and by the addi-
111-27
-------
0)
N
•rl
CM
rH
CO
0)
VI
§>
111-28
-------
tion of substances that tie up
the calcium. In waters with high
sulfate concentrations, calcium
sulfate, barium sulfate, and
strontium sulfate may also foul
the membrane. Calcium fluoride
has also been found to be a
problem. In most cases hexameta-
phosphate may be added to tie up
the calcium and prevent precipi-
tation on the membrane.
Suspended matter can cause plug-
ging of the membrane, thus reduc-
ing the flow of water through the
membrane. Generally, suspended
solids in the feed water are
reduced by a 5 to 10 micron
filter ahead of the membrane. A
measure of this type of interfer-
ence is the Silt Density Index
(SDI). SDI is measured by pass-
ing the raw water through a
0.45-micron filter at a pressure
above 30 pounds per square inch
gage (psig). The time (seconds)
required to collect 500 milli-
leters (ml) is recorded. After
an elapsed time of 5 minutes,
fresh water is again passed
through the same filter and the
time to collect 500 mis is re-
corded. This procedure is re-
peated again after total elapsed
times of 10 and 15 minutes.
The SDI is
SDI - Pnn
(1-ti/tf) (100)
T
where T is the total test dura-
tion (seconds), P_ is the percent
pluggage at 30 psig pressure, ti
is the initial time (seconds)
required to obtain the first
500 ml sample, and tf is the time
(seconds) required to obtain
respective samples after elapsed
times of 5, 10 and 15 minutes.
The SDI is calculated for each
time interval. Most waters have
an SDI value less than 3. Re-
verse osmosis cannot be used on
waters wth an SDI greater than 6.
Iron and manganese oxides can
also cause fouling of membranes.
Iron concentrations in the raw
waters should be less than 5 mg/1
if no oxygen is present, and less
than 0.05 mg/1 if the dissolved
oxygen concentration is 5 mg/1 or
above. In cases where iron or
manganese concentrations are
greater than recommended for RO
use, some form of iron and man-
ganese removal such as aeration
followed by settling or filtra-
tion may be necessary.
Because of the number of materials
which can foul an RO membrane and
deterioration of the membrane
material with time, design of RO
systems are normally conservative
so that the system can provide
desired treatment over the life-
time of the membrane. In the
design example in Section IV,
this approch is discussed more
fully.
Other Factors Influencing
Operation
Other factors which affect RO
performance include bacteria
which may accumulate on the
membrane and cause fouling. Some
bacteria have been found to
attack the membrane. . Temperature
also affects performance, which
is generally improved as tempera-
ture increases; however, if water
temperature is above that recom-
mended by the manufacturer, the
performance will be decreased.
This will depend on the type of
membrane materials. Finally,
chlorine will also attack certain
membrane materials, expecially
the aromatic polyamide manufac-
tured by DuPont.
111-29
-------
Since RO concentrates the solids
in the reject stream, this stream
will be much more concentrated in
dissolved materials, including
salts and radionuclides, than the
feed water and disposal may be a
difficult problem. The salinity
of the reject stream is generally
of more environmental concern
than its radionuclide content.
Section V addresses disposal
options and regulatory concerns.
The permeate contains carbon
dioxide as a result of the low
pH. Carbon dioxide can be re-
moved easily in post treatment by
aeration in a forced draft aerator
called a "decarbonator."
Suppliers of Reverse Osmosis
System
Table 3-5 is a partial list of
U.S. reverse osmosis equipment
manufacturers and suppliers.
Most of these manufacturers
provide RO modules for any size
range including point-of-use.
Most will also provide design and
analytical services to assist in
the selection and design of RO
systems, including requirements
for pre- and post-treatment
equipment.
Radionuclide Removal by Reverse
Osmosis
Reverse osmosis will remove about
95 percent of radium and uranium
in the feed water of a single
pass system. The removal of the
radionuclide is not directly
affected by the removal of any
other particular substance,
including hardness; unlike the
lime-soda and ion exchange soft-
ening processes. The degree of
removal by an RO system is called
the rejection rate. It is deter-
mined by the membrane material,
module design as well as operating
conditions such as pressure, and
the quality of the feedwater. An
advantage of reverse osmosis is
its high rate of rejection of all
dissolved solids in the feedwater.
This rejection rate allows brackish
and sea water to be desalted for
potable use. It also allows RO
to be used to treat water for
man-made radionuclide removal.
Permeate from an RO system will
be very low in hardness and free
from many other organic and
inorganic contaminants.
Advantages and Disadvantages of
Reverse Osmosis for Radionuclide
Removal
The advantage of reverse osmosis
for radionuclide removal are:
1. High rate of rejection of
nearly all dissolved solids
in raw water, including
radium, uranium and many
man-made radionculides.
2. Only process that can be
used on brackish or saline
waters (as compared to
ion-exchange or lime-
softening).
3. Process control is relatively
simple.
The disadvantages of reverse
osmosis for radionuclide removal
are:
1. High capital and operating
costs.
2. Considerable pretreatment
requirements, particularly
if raw water contains sus-
pended solids, organic
material, or dissolved
gases.
111-30
-------
TABLE 3-5
PARTIAL LIST OF REVERSE OSMOSIS SYSTEM SUPPLIERS
Company
Location
Basic Technologies
Envirogenics
Fluid Systems Division,
UOP, Inc.
DuPont
Dow Chemical Company
Infilco-Degreraont, Inc.
Neptune Microfloc
Permutit Company
Riviera Beach, Florida
El Monte, California
San Diego, California
Wilmington, Delaware
Midland, Michigan
Richmond, Virginia
Corvallis, Oregon
Paramus, New Jersey
3. Reject stream requires
disposal. The relatively
high volume of this stream,
25 to 50 percent of treated
water volume, adds to disposal
problem.
4. Finished water must be
stabilized with lime or
other chemicals to prevent
corrosion in distribution
system.
111-31
-------
IV. DESIGNING A REMOVAL SYSTEM FOR NATURALLY OCCURRING RADIONCULIDES
INTRODUCTION
This section includes a discus-
sion of the factors considered in
the selection and design of a
removal system for naturally
occurring radionuclides (uranium
and radium). Any reference to
radionuclides in this section
implies only uranium or radium.
The section is organized to:
1. Present general considera-
tions and information neces-
sary in selection and design
of a radionuclide removal
system,
2. Present a discussion of
factors affecting the selec-
tion of an appropriate
treatment system, and
3. Show how to design a radio-
nuclide treatment system
(lime-soda softening, ion
exchange, or reverse osmosis).
This section also provides enough
information to familiarize the
designer with basic design consid-
erations and terminology for each
of the three treatment systems
considered as they relate to
radionuclide removal.
CONSIDERATIONS IN THE DESIGN OF A
RADIONUCLIDE TREATMENT SYSTEM
In the design of a radionuclide
removal system, as well as for
most of the water treatment
processes, the actual system
design is specific to the loca-
tion, raw water characteristics,
and consumptive water demands.
Depending upon the raw water
characteristics and type of
treatment process selected for
radionuclide removal, various
pretreatment and/or posttreatment
operations are required. The
need for pretreatment may result
from reduced performance caused
by materials contained in the raw
water. For example, iron and
manganese oxides can foul the
membrane of the reverse osmosis
(RO) process limiting the flow of
water. Removing these oxides or
preventing their formation prior
to the RO system through pretreat-
ment will then permit unhampered
use of the RO process for removal
of the radionuclide. Posttreatment
may often be necessary to adjust
the water quality following
treatment for radionculide removal
to ensure that the water meets
all drinking water standards,
including radionuclides, or to
make the water more palatable or
less corrosive. As with pretreat-
ment, the type of posttreatment
will depend on raw water charac-
teristics and the radionuclide
treatment method selected.
If the available nontreatment
alternatives (refer to Section III
for discussion) will not solve
the problem, or if a comparison
of nontreatment with treatment
alternatives is required before -a
decision can be made, then the
following factors must be
considered:
o
o
Raw water quality;
Finished water quality
requirements;
Treatment capability of
candidate system;
Pretreatment/posttreatment
requirements for each candi-
date system;
IV-1
-------
o Regulatory requirements,
including disposal of sludges
generated or reject process
streams;
o Site-specific limitations;
o Costs, including energy;
o Materials of construction;
and
o Availability of trained
operating and maintenance
personnel.
Three treatment processes capable
of removing radium were discussed
in Section III; lime-soda softening,
ion exchange, and reverse osmosis.
As discussed, ion exchange and
reverse osmosis will also remove
uranium but for ion exchange to
be effective, an anionic resin
will be necessary.
RADIONUCLIDE REMOVAL DESIGN
CHECKLIST
The initial step in the design of
any treatment process is extensive
information gathering. After the
problem is identified, all informa-
tion necessary to complete the
design, estimate costs, and make
purchasing decisions must be
compiled.
Table 4-1 lists information
necessary for the design and
decision making process. As with
any checklist, some of the infor-
mation may not be available
initially, but as the project
progresses this information
should be compiled. This informa-
tion, which is necessary for the
selection and design for a radio-
nuclide system, may also be
useful in reviewing current
operations and for future planning.
TABLE 4-1
RADIONUCLIDE REMOVAL SYSTEM DESIGN CHECKLIST
1. Determine Treatment System Capacity
Daily (24-hour) Product Water Requirements, (gallons)
Initial After 1 year After 3 years _
Peak (24-hour) Product Water Requirements (gallons)
Initial After 1 year After 3 years
Do water requirements include:
Fire protection? yes no
Daily maintenance shutdowns? yes no
Storage requirements (24 hours)? yes no
If yes, gallons
2. Determine Raw Water Quality
Total Hardness (as CaCO ) mg/1
Radionuclides
Radium 226 and Radium 228 (pCi/1)
Uranium (pCi/1)
Total Suspended Solids (mg/1)
IV-2
-------
Total Dissolved Solids (mg/1)
Metals
Iron (Fe) (mg/1)
Manganese (Mn) (mg/1)
PH
Temperature (°F) min mean max
Turbidity (NTU)
Silt Density Index
Hydrogen Sulfide (mg/1)
Carbon Dioxide (mg/1)
Taste and Odor
Color
3. Available Space
Is indoor space available? yes no
If yes, dimensions. (ft)
length height width
If no, land availability. length width
Access?
4. Disposal of Treatment Residues
a. Availability of Disposal Options
Discharge to:
Sanitary Sewer
Receiving Water
Sanitary Landfill
Storage:
Lagooning
Sanitary Landfill
Strip Mines and Quarries
Land Spreading
Disposal
In Deep Aquifers
In Oil Well Fields
As a Low Level Nuclear Waste
b. State Local Regulatory Restrictions Applicable to Available
Disposal Options (Contact Appropriate State Agency)
5. Desired Finished Water Parameters
Radium 226 and Radium 228 (pCi/1)
Uranium (pCi/1)
Hardness (CaCO ) (mg/1)
Color
Turbidity (NTU)
IV-3
-------
Odor
Pressure (psig) required for
distribution
Iron and Manganese (mg/1)
Chlorine Residual (mg/1)
6. Availability of Utilities
Electricity:
Voltage
Cost $
Phase
/kwh
Cycles
Steam
Pressure (psig)
Standard Cubic Feet/Minute (SCFM)
Cost $ /lb
Air
7.
8.
Plant (psig).
Instrument (psig).
Cost $ /SCFM
Labor
Category
Foreman
Class A Operator
Class B Operator
Class C Operator
Available Funding
Sources
Private
Bond
(SCFM)
(SCFM)
Cost $/hr
Interest Rate
Term (years)
Local Government
When using this checklist, if the
reader is unfamiliar with termi-
nology or with the calcuation or
identification of information, it
is suggested he consult a suitable
reference text such as: a state
published operator training
guide, the Ten States Standard
for Potable Water Quality, or The
American Water Works Association
publications such as "Water
Treatment Plant Design" (1969).
As the investigation, design, and
selection of a radionuclide
removal system is continued and
vendors are contacted, additional
information helpful to the design,
selection, or implementation
process may be obtained. It is
suggested that this information
also be recorded on the design
checklist.
IV-4
-------
SELECTION OF A RADIONUCLIDE
TREATMENT SYSTEM
Once characteristics of the water
and any existing treatment system
have been compiled, several
preliminary decisions regarding
the selection of the radionuclide
removal system can be made.
There are five general criteria
for selection of a treatment
system, namely:
o Technical feasibility,
o Cost,
o Site limitations,
o Compatibility with existing
treatment, and
o Preference
The performance and operation of
the three treatment processes
were discussed in Section III.
Potential use and limitations of
each technology were discussed,
but will be readdressed in this
section to direct the designer to
the treatment process which may
be technically feasible and to
eliminate any process which may
not be suited to a particular
water or site.
Technical Feasibility
Limitations of Lime-Soda Softening
for Radionuclide Removal
Lime softening is generally not
the treatment of choice for
waters with total hardness above
400 mg/1 if it is the sole treat-
ment process. There are two
reasons for this: (1) the total
dissolved solid (TDS) in the
water would most likely be above
750 mg/1 and, therefore, even
after treatment the TDS would
remain above the 500 mg/1 required
by the secondary drinking water
regulations, and (2) the cost of
chemicals and handling requirements
would make the process impractical,
especially for the small user.
To use this process for radium
removal effectively, the radium
concentration should be less than
25 pCi/1, then an 80 percent
removal would be sufficient to
meet the 5 pCi/1 MCL. As dis-
cussed in Section III, this is an
appropriate upper limit of technol-
ogy. Because of the limited data
on uranium removal by lime-soda
softening and the high pH
(above 10.6) observed to be
necessary in bench studies,
lime-soda softening may not be
applicable to waters contaminated
wth uranium.
Another limitation of the technol-
ogy is the volume of water to be
treated. Systems where less than
about 75,000 gallons per day are
treated may find difficulty
obtaining appropriate equipment.
The required labor for maintenance
and operation of a lime-soda
softening system may also be
beyond the available labor support.
Limitations of Ion Exchange for
Radionuclide Removal
With proper identification and
implementation of pretreatment
processes, ion exchange is capable
of removing radium or uranium
from most water supplies. However,
waters with total dissolved
solids (TDS) much above 500 mg/i
are not amenable to treatment by
ion-exchange systems using salt
as a regenerant because of the
resulting increase in TDS. As
discussed in Section III, calcium
ions will be exchanged by sodium
ions, thus the discharge from the
ion-exchange column will be
increased in sodium concentration.
If the water prior to possible
IV-5
-------
treatment by ion exchange contains
an appreciable concentration of
sodium, the use of ion exchange
should be carefully considered to
ensure the drinking water limita-
tions for sodium are not exceeded.
The disposal of regenerant brine
and backwash water may restrict
the use of the ion-exchange
technology. If brine disposal is
not permitted due to local regula-
tions or to lack of a suitable
nearby disposal site, then ion
exchange may not be a feasible
alternative or may be too costly.
Because of the limited, although
favorable, data on uranium removal
using an anionic ion-exchange
resin, the use of this technology
on waters containing uranium
should be carefully considered
and performance verified by
experimental study before the
preparation of a system design.
Limitations of Reverse Osmosis
for Radionuclide Removal
Reverse osmosis (RO) has been
used to effectively remove the
naturally occurring radionuclides,
radium and uranium as well as
man-made radionuclides. Reverse
osmosis can be applied to most
contaminated sources effectively
if a sufficient number of RO
modules are used, membranes are
properly selected, and required
pretreatment is applied. Reverse
osmosis treatment of water can be
limited by the presence of several
constituents of the untreated
water, but is generally applied
to systems where high purity
water is required and is normally
applied after one or more pretreat-
ment steps. Waters which contain
high concentrations of calcium
carbonate or calcium fluoride,
and the sulfate salts of calcium,
strontium, or barium may require
pretreatment by adjustment of the
pH or by the addition of an
inhibitor. If these salts are
present in high concentrations
and pretreatment is not practiced,
they may precipitate on the
membrane, thereby restricting the
passage of water. Likewise,
oxides of iron and manganese will
also foul the membrane. Pretreat-
ment can be used to remove or
"tie up" these compounds and
allow treatment by RO.
Suspended solids and particle
size must be controlled to ensure
successful RO treatment. Sus-
pended solids entering the RO
membrane must be kept low to
permit operation of the system.
Particle size of solids entering
the RO membrane are generally
kept below a 10 micron particle
size by means of an in-line
cartridge filter.
The use of RO is also limited by
the presence of colloidal mate-
rials. Colloids are finely
dispersed particles that are
difficult to remove by conven-
tional filtration techniques.
The RO membrane will not permit
the passage of these materials
and with time they will plug the
membrane and prevent passage of
water. An index used to measure
potential colloidal interference
is the Silt Density Index (SDI),
which is discussed in detail in
Section III. Most waters have an
SDI of less than 3. RO is gen-
erally not applicable to waters
with SDI's of above 6.
Temperature is also a limitation
in the design of an RO system.
Most RO membranes are made to
operate at temperatures below
95°F. However, even at lower
temperatures, RO membrane perform-
IV-6
-------
ance is temperature dependent.
The higher the temperature, the
faster the membrane loses its
capacity to reject dissolved
materials. In addition, the
long-term performance of the
membrane is less at higher tem-
peratures than at lower
temperatures.
Clos t
In selection of any treatment
process, the initial and operating
costs are important considerations.
Initial costs generally increase
as the volume of water treated
increases, while unit operating
costs generally decrease. Of the
three processes considered,
lime-soda softening is the most
labor and chemical intensive.
Reverse osmosis, because of the
high pressure pumps required for
operaton, has the highest energy
cost. Methods to determine
initial and operating costs for
the three technologies are pre-
sented in Section VI. It is
suggested that several manufac-
turers be contacted to obtain
costs more specific to the indi-
vidual site.
When considering costs, a system
with higher initial costs should
not be immediately ruled out
until after operating costs and
other factors discussed in this
manual have been considered. For
example, an ion-exchange system
may be far less expensive to
purchase than a similar capacity
reverse osmosis system, but
convenient disposal of the brine
regenerant may not be possible,
or may be so expensive as to
overcome the advantage of the
lower capital cost.
Site Limitations
Site-specific limitations will
impact the choice of the equipment
as heavily as does the raw water
quality. Table 4-2 lists several
site restrictions to be considered.
The space available for locating
the system should be measured and
assessed for suitability for
erecting a system. Plans should
be modified, if necessary, to
obtain public acceptance of the
treatment system and location.
In communities where the public
participates in decision making,
such as in condominiums, public
participation in the selection of
the plant site and treatment
system may not only be convenient,
but necessary. Local zoning,
construction, and permit require-
ments should be investigated and
addressed.
Although the systems can be
automated, maintenance by an
operator is required on a routine
basis. If a system smaller than
required is installed, it may be
operated more frequently or at
greater rates requiring more
frequent and extensive maintenance.
This will not only increase
treatment costs, but the need for
skilled operators, as well.
Provisions for removal of treatment
sludges and disposal of regenerants
or rejected portions (reverse
osmosis) should be investigated
from regulatory and handling
viewpoints.
The choice of construction mate-
rials is also dependent on the
individual site chosen. If the
facility is to serve the community
for a number of years rather than
on a temporary basis, then more
costly corrosion-resistant mate-
rials should be chosen, although
IV-7
-------
TABLE 4-2
SITE LIMITATIONS AFFECTING TREATMENT SELECTION
Site Limitations
Disposal of Rejected Portion and Treatment Sludges
Space
Available Finished Water Storage
Maintenance
Regulatory Requirements
Expansion (Demand)
Availability of Trained Personnel
Chemical Storage Availability
Frequency of Operation
Maximum Anticipated Idle Period
Source: ESE, 1981.
similar, less-expensive equipment
may be available. This less-
expensive equipment, however, may
be subject to greater corrosion.
Compatibility with Existing
Treatment Equipment
For water supplies where some
form of treatment is already
being applied, the incorporation
of as much of the existing equip-
ment as possible may be advanta-
geous from a cost, as well as a
technical, perspective. Filtra-
tion and disinfection by chlorina-
tion are the predominant forms of
treatment for the small utility.
If the raw water is currently
being filtered, filtration would
most likely continue to be re-
quired prior to the ion-exchange
or reverse osmosis system. The
ion-exchange contactors or re-
verse osmosis modules may be
added on, perhaps, directly after
the filters. Chlorination of the
effluent from either process is
still required.
Lime-softening, however, may be
more difficult to add on since
filters are required after the
lime-softening process. Use of
lime-softening would require more
piping changes and perhaps re-
placement of existing pumps.
Preference
The final selection of a process
may not be clearly indicated by
performance limitations, costs,
or site-specific limitations.
The choice of the system may be
more of preference. The local
developer or residents may not
wish an unsightly storage or
process tank needed for lime-soda
softening, but rather may prefer
a housed system. Ion-exchange
columns and reverse osmosis
systems are generally placed
inside a building.
Other preferences may be based on
the availability of operating and
maintenance personnel or on the
adaptability of the system to
IV-8
-------
expansion. The lime-soda soften-
ing process requires greater and
more frequent attention than do
the other processes. It is also
easier to add on reverse osmosis
modules or ion-exchange columns
(assuming pretreatment is ade-
quate) than to expand a lime-
softening system.
PILOT STUDIES FOR EVALUATING
RADIONUCLIDE REMOVAL PROCESSES
The technologies which effectively
remove radionuclides from water;
lime-soda softening, ion exchange,
and reverse osmosis; have been
extensively studied for hardness
or dissolved solids removal. The
effectiveness of these technolo-
gies to remove hardness and other
dissolved materials from water,
including radium, is well docu-
mented. Their use, however, for
removal of uranium has not been
investigated in detail. The
effects of raw water characteris-
tics on the performance of each
of these technologies for hardness
or TDS removal is understood and
can be predicted. From the raw
water characteristics, most
design criteria for radium removal
for each of the systems can be
developed either through water
chemistry, established design
correlations, or manufacturer
experience. Pilot studies are,
therefore, not generally neces-
sary to confirm removal of radium
or to establish design criteria
for these processes. Batch tests
called isotherms, which consist
of shaking a resin with the water
to determine the capacity of a
resin, however, may be conducted
by a manufacturer to determine
the best resin for the ion-
exchange process. The cost of
conducting a pilot study, espe-
cially if radionuclides are to be
monitored, can be a major portion
of the total engineering and
construction costs for the project.
Because of the limited data on
the removal of uranium, laboratory
or bench studies should be con-
sidered. Since only ion-exchange
and reverse osmosis are considered
technically feasible for removal
of uranium, studies first using
an anionic exchange resin and
then using reverse osmosis should
be conducted. This order is
suggested because if ion exchange
is not satisfactory, the choice
becomes one of selecting the most
appropriate reverse osmosis
membrane and system.
DESIGN OF A LIME-SODA SOFTENING
SYSTEM FOR RADIUM REMOVAL
As discussed in Section III, the
lime-soda process is used to
remove calcium and magnesium ions
from water in a softening plant.
It also removes radium along with
the other metals because radium
is chemically similar to calcium
and magnesium. If the plant is
to be designed or operated for
radium removal rather than soft-
ening, the operating conditions
might be quite different. For
example, Figure 3-5 showed that
increasing the pH from 8.0 to 9.5
has little effect on radium
removal but that change could
have a noticeable effect on
softening.
Analysis Required for Designing
A Lime-Soda Softening System for
Radium Removal
To estimate the amounts and kind
of chemicals to be used and to
size the plant, the following
parameters should be determined:
IV-9
-------
3*
A. Chemical
1. pH;
2. IDS, mg/1;
3. Total Alkalinity, mg/1 as
CaCO ;
4. Calcium, mg/1 as CaCO ;
5. Magnesium, mg/1 as CaCO
6. H.S, mg/1; and
7. Radium, pCi/1.
B. Physical
1. Temperature, °C or °F;
2. Peak demand, gpd; and
3. Average demand, gpd.
Pretreatment Prior to the Lime-
Soda Softening Process
Because of the high pH of soften-
ing and the long reaction times
in the treatment plant, the usual
contaminants that require pretreat-
ment are removed in the softening
step. The exceptions may be
carbon dioxide and hydrogen
sulfide.
Since CO. reacts with lime and
H S has a bad odor, some plants
aerate the raw water for the
removal of either or both of
these before softening. Unless
the amounts are relatively high,
it is usually better to avoid
aeration. Aeration saturates the
water with dissolved oxygen (DO)
which makes it much more corrosive,
leading to or aggravating red
water problems and water main
deterioration if iron pipe is in
use.
Design Criteria for the Lime-
Soda Softening Radium Removal
Process
To design a lime-soda softening
plant for radium removal, it is
necessary to decide what type of
plant to consider. The two
general types are the horizontal
flow plant with separate mixing,
flocculation, and sedimentation
basins, and the up-flow unit in
which all the mixing and settling
take place in the same basin.
Most small plants and many large
softening plants use the latter
type because it requires less
space and energy. Up-flow units
use less space because they are
designed to mix recycled sludge
with the water being treated.
This improves the rate at which
the precipitates are formed and
makes the particles much larger.
Therefore, they settle much,
faster allowing the use of a
smaller volume for sedimentation.
The information needed to design
the up-flow type unit more com-
monly used for small water sys-
tems are:
1. Settling velocity of solids
formed. This is used to
determine the surface loading
rate of the sedimentation
section of the unit (4 cm/min
settling velocity equals
1 gal/min-ft ).
2. Hardness removal (and,
therefore, radium removal),
which is necessary in order
to determine the amount of
sludge that will be generated
and which then must be
disposed of.
3. Settled water turbidity in
order to estimate the type
of filter design and filter
backwash required.
4. Maximum daily demand to be
used for sizing the units.
5. Dosages of chemicals for
sizing feeders or solution
tanks.
IV-10
-------
Factors Which Influence Chemical
Dosage in the Lime-Soda Softening
Process
Of the factors that must be
considered in designing the
treatment system, several affect
the type and amount of chemicals
to be fed into the untreated
water. Lime (CaO) and soda ash
(Na^CO ) are the two chemicals
usea in this process. Terms
necessary to the discussion of
the softening process include:
1. Total hardness—the total of
the calcium plus magnesium
hardness.
2. Carbonate hardness—that
part of the total hardness
which is equivalent to the
total alkalinity; all forms
of hardness and alkalinity
are expressed as mg/1 of
calcium carbonate (CaCO ).
3. Noncarbonate hardness—all
of the total hardness that
is not carbonate hardness.
That is, the total hardness
minus the carbonate hardness
or alkalinity equals the
noncarbonate hardness ex-
pressed as mg/1 CaCO .
4. Excess alkalinity (XS) of
35 mg/1 as CaCO—this is an
average value to raise the
pH to the point where magnes-
ium will precipitate as
Mg(OH) . Although the exact
value is hard to calculate,
it can be measured through
laboratory analysis.
In most cases where the process
is being designed for radium
removal rather than for softening,
it is possible to ignore magnesium
removal. Then, the only consider-
ation is calcium removal, which
uses less lime and soda ash.
As discussed in Section III,
radium is removed in the softening
process along with the hardness-
causing ions of calcium and
magnesium. Therefore, in designing
the softening process or in
estimating chemical dosages, only
the requirements to obtain soften-
ing and the relationship between
radium removal and hardness
removal need to be considered.
The amount of hardness removal
necessary to remove a certain
amount of radium, for example,
can be estimated with the aid of
Figure 3-4 (fraction of total
hardness removed versus fraction
of radium removed). The amounts
of lime and soda ash to be used
can be estimated from the equa-
tions presented in the following
discussion, but should be tested
first in laboratory analysis.
Adjustments can then be made in
dosages to attain the radium and
hardness removals necessary.
Sample Design of a Lime-Soda
Softening Process for Radium
Removal
Background
A small utility supplies an
average of 300,000 gallons of
water per day. Its well supply
was analyzed and found to contain
25 pCi/1 of radium. The total
hardness of the water was 240 mg/1
as CaCO with 10 mg/1 present as
magnesium hardness. The alkalini-
ty was 220 mg/1, while the free
carbon dioxide content was 40 mg/1.
Currently, the utility only
chlorinates the water. Lime-soda
softening is being considered for
radium removal if that would
solve the problem.
Step 1 - Calculate Required
Hardness Removal
IV-11
-------
The first step would be to calcu-
late the amount of hardness to be
removed along with the radium so
that the radium level would be
less than 5 pCi/1.
The fraction of radium to be
removed would, therefore, be:
25 pCi/1 - 5 pCi/1 ^ 0.80 or
25 pCi/1= 80 percent
From Figure 3-4, it can be
estimated that this fraction of
radium removal would require
about 50 percent (0.50) hardness
removal. This means that 50 per-
cent of the original total hard-
ness of 240 mg/1, or 120 mg/1
would have to be removed. Since
the carbonate hardness was 220 mg/1
(equal to the alkalinity), 120 mg/1
of calcium carbonate hardness
would have to be removed by
reacting with lime added for the
treatment process. Since the
water contained 40 mg/1 of CO
(as CaCO ) this, too, would react
with lime.
If all of the carbonate hardness
were to be removed, the final
hardness would be about 65 mg/1
(35 mg/1 as calcium because of
its solubility, 20 mg/1 of non-
carbonate hardness and 10 mg/1 as
magnesium, since none need be
removed. The hardness removed is
therefore:
240 mg/1 - 65 mg/1
240 mg/1
73 percent
which is above the 50 percent
hardness removal necessary to
reduce the radium concentration
to 5 pCi/1. Therefore, only the
120 mg/1 needs to be reacted with
lime plus about 35 mg/1 as CaCO
for the solubility.
Step 2 - Determine Lime Requirements
The amount of lime needed is
determined by using the following
set of simple equations for
estimating the chemical dosages:
1. Removal of carbonate hardness
and magnesium: pounds/mil-
lion gallons (Ib/MG) of
100 percent quicklime (CaO) =
(56/44 x 8.34) (CO in
mg/1) + (56/100 x 8.34)
(alkalinity in mg/1 as
CaCO + magnesium hardness
in mg/1 as CaCO + excess of
about 35 mg/1 as CaCQ ).
2. Removal of noncarbonate
hardness: Ib/MG of 100 per-
cent soda ash (Na CO ) =
106/100 x 8.34 = 8.8J(noncar-
bonate hardness in mg/1 as
CaCO - noncarbonate hardness
remaining in the softened
water).
Step 3 - Correction for Lime
Purity
It is assumed that the small
water system would purchase lime
already in the slaked form and
not of 100 percent purity, hence,
the dosage must be corrected for
purity.
The correction for the percent
purity is made by dividing the
calculated dosage by the purity,
that is, the percent purity
divided by 100. Example: a
dosage of 150 Ib/MG of 100 percent
CaO would be 161.3 Ib/MG of
93 percent pure commercial quick-
lime (CaO). Calculated as:
150 Ib/MG ; 0.93 purity =
161.3 Ib/MG.
The correction procedure for
hydrated lime instead of CaO is
IV-12
-------
to multiply the CaO dosage by
74/56 = 1.32 [the ratio of the
respective molecular weights,
i.e., hydrated lime (74) to that
of calcium oxide (56)]. Soda ash
dosages do not need to be cor-
rected since commercial grade is
almost 100 percent pure.
Step 4 - Summary of Chemical
Requirements
For this example, then, the
chemical requirements are:
Ib/MG of 100 percent pure CaO =
10.6 (C02, mg/1)
+4.7 (alkalinity, mg/1 as
CaC03 + 35 mg/1 XS)
= 10.6 (40) +4.7 (155) =
1,152.
This is 1,152 x 74/56 =
1,522 Ib/MG 100 percent Ca(OH)
or 1,637 Ib/MG of 93 percent
Ca(OH)2.
Step 5 - Daily Chemical Usage
For a plant flow of 300,000 gpd,
then, the actual daily chemical
usage would be:
0.3 MG/day
1.0 MG/day
x 1,637 Ib/MG =
491 Ib/day of 93% Ca(OH)2
This could be used as a starting
point in a laboratory study to
check its accuracy. [For labora-
tory studies this would be equiva-
lent to 182.5 mg/1 of laboratory
grade, 100% Ca(OH)2.]
The plant should be designed,
however, to treat at least twice
the average flow to meet peak
demands. Therefore, the chemical
storage facility should be sized
to feed chemicals to a 600,000 gpd
plant, or about 1,000 Ib/day of
lime.
Step 6 - Sizing of Treatment Unit
Results from laboratory studies
recommended for evaluating the
lime-softening process showed a
settled water turbidity of less
than 5 NTU could be obtained at a
settling velocity of 10 cm/min
(or 2.5 gpm/ft surface loading
rate). Five (5) NTU is the
amount of turbidity considered to
be suitable as influent to polish-
ing filters without causing
operational problems. This
settling velocity or surface
loading rate allows the calcula-
tion of the minimum size of the
treatment unit. For 600,000 gpd,
this is a surface area calculated
as:
600.000 gpd 1 ft
1,440 mpd x 2.5 gpm
= 167 ft'
or a circular unit with about a
15-foot diameter. This must be
increased to account for the area
to be occupied by the central
mixing zone.
Filters must be included to
polish the water (remove any
unsettled particles) before
distribution in order to meet the
1 NTU turbidity standard.
Laboratory Studies
Although chemical dosage can be
estimated from the equations
presented, small scale studies in
the laboratory, called "jar
tests," can determine the amounts
of chemicals required to obtain
the radium removal necessary.
These studies can also test
different substances that increase
IV-13
-------
the settling rate of the precipi-
tates, so-called coagulant aids.
The results of the jar test can
then be used to specify the type
of chemical coagulant and the
required dosage.
DESIGN OF AN ION-EXCHANGE TREAT-
MENT SYSTEM FOR RADIUM REMOVAL
Ion-exchange treatment for the
removal of radionuclides was
discussed in Section III. Cation
exchangers can remove more than
95 percent of radium applied to
the resin column and can be
regenerated, following exhaustion,
using a concentrated salt solution.
Uranium removals of 99 percent
through an anion exchange resin
such as Dowex 1-X2, have been
shown to be possible in labora-
tory studies when followed by
regeneration with mixed sodium
chloride and sodium bicarbonate
solution. Only radium removal,
however, is considered in this
section since its removal by
resins has been more thoroughly
studied. The operational cycle
of the ion-exchange column was
discussed in Section III. Also
presented were several design and
operational concerns. The perform-
ance and operational requirements
of each of the sequences in the
cycle, radionuclide removal -
exhaustion-regeneration-backwash,
dictate the design of the column,
regenerant storage, and waste
stream disposal. The raw water
analysis will reveal pretreatment
requirements which can be further
determined through bench or pilot
testing.
Pretreatment Prior to an Ion-
Exchange System
The ion-exchange resin is a
spherical, synthetic bead of
uniform shape and particle size.
When placed into a column, the
beads provide filtration of
suspended matter and act as
potential sites for promoting
biological growths. Filtered
suspended matter and biological
slime growths will reduce the
hydraulic capacity of the resin
or perhaps cause the feed water
to channel around the resin. If
this occurs, the water to be
treated will not make proper
contact with the resin, which
results in decreased performance.
Generally, waters with turbidity
above 2 NTU's are pretreated by
sand filtration before ion
exchange.
If bacteria are present in the
water supply, prechlorination can
provide sufficient control to
prevent biological growths within
the resin column.
The cation exchanger will remove
calcium and magnesium ions as
well as those of the radium.
High hardness will exhaust the
capacity of the bed more rapidly.
Thus, the column size must be
increased or the frequency of
regeneration will have to be
increased substantially increas-
ing the operational costs. For
these cases, a cost comparison
should be made between lime-soda
softening and ion-exchange
softening.
For most waters, especially for
the removal of uranium by an
anion exchange resin, pH adjust-
ment will be necessary, either to
obtain desired removals or to
optimize the performance of a
specific resin on a particular
water supply.
IV-14
-------
Analysis Required for the Design
of an Ion-Exchange System for
Radium Removal
Table 4-3 lists information that
is necessary for the design of a
radium removal system, including
ion-exchange treatment. It also
aids in developing a complete
understanding of the present
treatment system, or in the
determination of future needs.
The use of these parameters has
been discussed in the section
regarding consideration of pre-
treatment processes. With the
exceptions of the radium concen-
tration, these analyses may
already be performed routinely.
Certified laboratories should be
contacted for any analyses not
done at the plant.
Pilot Testing of Ion-Exchange
Systems for Radium Removal
Following the characterization of
the raw water, including the
parameters listed in Table 4-2, a
resin manufacturer, or an equip-
ment supplier (Table 3-3) should
be contacted. The vendor, after
reviewing the analysis and the
utility's needs, may suggest
bench isotherm tests before
recommending a resin or a system.
The vendor, in most cases, can
perform these tests on a sample
of the water. The isotherm,
which determines capacity of a
resin for removing an ion, is
useful in determining whether the
desired removal can be obtained
for a particular water. In
addition, isotherms are useful in
determining relative performance
of the resins tested, the optimum
TABLE 4-3
ANALYSIS REQUIRED FOR DESIGNING AN ION-EXCHANGE SYSTEM
FOR RADIUM REMOVAL
o Peak water demand, gpd
o Average water demand, gpd
o Radium concentration, pCi/1
o Total hardness, mg/1
o pH
o Total dissolved solids, mg/1
o Turbidity, NTU
o Temperature, minimum °F
IV-15
-------
pH range, approximate regenerant
requirements, and pretreatment
requirements. Since hardness
removal is an indicator of the
capacity of a resin to remove
radium, the manufacturer may
choose to base performance on
using the inexpensive analysis of
hardness rather than the more
costly radium analysis.
Design Criteria for an Ion-
Exchange System for Radium Removal
As previously discussed, there
are four cycles comprising the
operation of an ion-exchange
system; removal-exhaustion-
regeneration-backwash. Each is
dependent upon a characteristic
of the water, and impact on the
design criteria. The removal
cycle is dependent on the radium
concentration and the volume of
water to be treated. This deter-
mines the type of resin and,
combined with the capacity of the
resin for hardness removal,
determines the volume of resin
material required to treat the
water between regenerations.
This also determines the run time
(or volume of water that can be
treated) prior to exhauston. The
volume of regenerant required
after each removal cycle depends
on the volume and type of resin.
The size of the regenerant tank
and disposal system is then
determined from the regenerant
requirements.
The backwash rate is determined
by the type of resin and the
temperature of the water. Once
the backwash rate is established
the overall height of the column
can be calculated.
The basic parameters that must be
established to specify a radium
removal system are listed in
Table 4-4.
Sample Design of an Ion-Exchange
System for Radium Removal
Step 1 - Select Resin and Deter-
mine Capacity for Radium Removal
Resin selection is dependent on
the water analysis, results from
pilot testing, if conducted, and
manufacturers' recommendations.
Table 3-3 lists suppliers of
ion-exchange resins and system
vendors. The manufacturers will
provide detailed application
guides and pretreatment require-
ments for their resins or equipment.
The manufacturers should provide
information in terms of resin
capacity or run length. Resin
capacity can be measured as the
gallons of water which can be
treated per cubic foot of resin
to the point of exchange exhaus-
tion. Exhaustion occurs when the
exchanger fails to provide the
degree of contaminant removal
necessary to maintain acceptable
water quality. At exhaustion the
exchanger is removed from service
and regenerated.
If a manufacturer supplies a
modular system with a fixed
volume of resin, then based on
past experience or pilot or bench
studies, a run length in terms of
service hours for production of
acceptable water will be provided.
Step 2 - Blending
Since ion exchange can remove up
to 95 percent of the radium
present, not all the flow may
need to be treated. As discussed
in Section III, a portion of the
water can be blended with the
untreated water to provide a
treated water meeting the MCL.
IV-16
-------
TABLE 4-4
BASIC DESIGN INFORMATION FOR ION-EXCHANGE SYSTEM
Flow, gpd
Resin type
3
Resin volume, ft
Column diameter, ft
Column height, ft
2
Surface loading rate, gpm/ft
2
Backwash flow rate, gpm/ft
Bed expansion at backwash flow rate, percentage (%)
Service cycle time, hrs
3
Regenerant dosage, Ibs regenerant/ft resin
Volume of regenerant, gal/cycle
2
Regenerant flow rate, gpm/ft
Regenerant contact time, min
Regenerant storage volume, gal
As an example, assume a utility
supplies water to a small commun-
ity. The ground-water source has
been found to have 10 pCi/1 of
radium present. Purchased water
from a nearby municipality has
been investigated, but is con-
sidered too costly. Water demands
are projected to be at most
250,000 gallons per day for the
next 3 years. Ion exchange is
being considered as a preferred
treatment alternative. Since the
system will remove up to 95 per-
cent of influent radium concen-
tration, blending with untreated
water should be considered to
minimize the size of the system.
Figure 4-1 relates the fraction
of water that needs to be treated
for various raw water influent
radium concentrations. This
figure is based on a performance
efficiency of 95 percent radium
removal and assumes that the
ion-exchange resin will be ex-
hausted when removal drops below
95 percent. Before using this
figure, testing should be per-
formed with one or more resins to
confirm that such removals are
possible with the water to be
IV-17
-------
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o
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o
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6
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o
00
o
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o
o
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i
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6
8JD8JJ
i r
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6 6
1 UOIJ.OOJJ
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IV-18
-------
treated. For this example, if
95 percent radium removal were
confirmed, then from Figure 4-1
for a raw water concentration of
10 pCi/1, 50 percent of the flow
(or 125,000 gpd) requires
treatment.
If, however, only 90 percent
removal and not 95 percent removal
were possible, the fraction
treated would be calculated by
using the following equation:
where:
fraction treated
C = desired concentration of
radium after treatment (5 pCi/1
for this example)
C = untreated water radium
concentration (10 pCi/1 for
this example)
e = efficiency of treatment
system (90% or 0.9 for this
example)
therefore:
10-5
f -
(10)(0.9)
f - 0.56
Thus, the treated flow would
be 0.56 (250,000 gpd), or
HO, 000 gpd.
Step 3 - Calculate Required
Ion-Exchange Bed Volume
The amount of resin required in
the ion-exchange system, known as
the bed volume (BV), is determined
from three factors:
o Specific capacity of the
resin
o Desired (assumed) lifetime
between regenerations
o Manufacturer's recommended
resin bed depth (ft) and
surface^loading rate
(gpm/ft )
Assume for this example that the
resin can treat 10,000 gallons of
water per cubic foot of resin
before the resin can no longer
remove 90 percent of radium at an
influent concentration of 10 pCi/1.
This information can be obtained
from bench or pilot scale testing.
Based on the blending calculation,
140,000 gallons/day requires
treatment. If it is decided to
regenerate the resin only once
per week, the required resin
volume is calculated by:
Cubic feet of resin =
Volume of water treated/day x
days between regeneration
Resin Capacity (gallons/cubic foot)
= 140,000 gpd x 7 days
10,000 gal/ft3
= 98 ft3
The manufacturer will specify
surface loading rates and minimum
acceptable bed depths for the
resin bed as well as backwash
flow rates. A minimum bed depth
is required to provide sufficient
contact of the water with the
resin to assure that the required
levels of contaminant removal are
met.
For this example, assume that the
manufacturer recommends a surface
loading rate of 4 gpm/ft , a
minimum resin depth of 30 inches,
and a backwash rate of 8 gpm/ft .
The column diameter for a single
column would be calculated as:
IV-19
-------
Total flow (gallons/minute,
gpm) = surface area (ft ) x 2
surface loading rate (gpm/ft )
140,000 g/day
1,440 min/day
Flow
97.22 gpm
Area (ft )
flow
97.22
surface loading rate
Also area
4 gpm/ft
24.3 ft2
Then diameter of column = D =
1/4 Area _1 7(4) (24. 3)
= 5.56 ft
This should be rounded to the
next higher whole number, i.e.,
6 ft, as a standard size.
The bed depth would be based on:
3 2
Volume (ft ) = TTr h
or h
3.47 ft
or
42 in
Backwash allowance is dependent
upon the size and density of the
resin with expansion of the resin
a function of backwash flow rate.
Curves are provided by the manu-
facturers which relate expansion
to backwash flow rate (gpm/ft ).
Backwash expansion is temperature
dependent with greater expansion
at lower temperature. This
dependency is related to the
viscosity of water which is
temperature dependent. Manufac-
turers provide expansion curves
for several temperatures. If a
curve is not provided for a
temperature near the minimum
operating temperature, then the
expansion can be calculated by
knowing that the percent expan-
sion is directly related to the
viscosity, or
1
1
E.
For example, at a backwash flow
of 8 gpm/ft and a temperature of
70°F, the expansion determined
from the curve is 25 percent (E,).
The expansion at 50°F (E ) would
be calculated from the relationship
or
This is greater than the minimum
required depth of 30 inches.
Step 4 - Calculation of Column
Dimensions
The diameter of the column would
be 6 feet as calculated. The
column sidewall height will be
determined from the calculated
resin depth and a freeboard
allowance for backwashing.
Backwashing is required following
regeneration to remove residual
regenerant and to wash out any
suspended solids that have been
removed through filtration.
E = % expansion at 50°F =
(viscosity at 50°F)(E )
(viscosity at 70°F)
from a handbook such as the
Handbook of Chemistry and Physics
(CRC Publishing Company), the
viscosities are 0.9810 centipoises
at 70°F and 1.3077 centipoises at
50°F.
IV-20
-------
The % expansion is then =
25 (1.3077)
(0.9810)
or
33%
Thus, at this temperature and for
backwash flow rate of 8 gpm/ft
and a resin depth of 42 inches,
the required column residual
height is 42 x 1.33 = 56 inches.
Therefore, the column would be
6 feet in diameter and at least
56 inches in height.
Step 5 - Calculation of Regenerant
Requirements and Sizing of Regen-
erant Storage Volume
The regenerant volume and concen-
tration are dependent on the
specific resin. This information
is provided by the resin manu-
facturer based on similar applica-
tions. The regenerant volume
used per cycle may vary from site
to site and sufficient extra
capacity should be provided in
the regenerant storage tank to
allow for possible greater regen-
erant use than initially
anticipated.
For this example, assume that
15 pounds of sodium chloride
prepared in a 10 percent by
weight solution is necessary to
regenerate a cubic foot of resin.
Therefore, for the 98 cubic feet
of resin:
98 ft3 x 15 lbs/ft3 =
1,470 Ibs of sodium chloride
The volume (gallons) of regenerant
for a 10 percent by weight solution
would be calculated as follows:
Specific gravity of brine solutions
can be obtained from a reference
source, such as the Handbook of
Chemistry and Physics. The
specific gravity of a 10 percent
sodium chloride solution
is 1.0707.
Therefore:
1,470 Ibs
1 Ib
10 Ibs
8.34 Ibs
gal
x 1.0707
1,646 gallons of a 10% sodium
chloride solution
Enough storage capacity should be
provided for 3 or 4 regeneration
cycles. The regenerant flow rate
for a 6-foot diamete^column with
loading at 0.5 gpm/ft
mined as:
is deter-
0.5 gpm/ft
2 2
(6r ft
= 14.1 gpm
Step 7 - Calculation of Regeneration
Cycle Time
The regeneration cycle time is
the time required to pass all the
regenerant through the resin bed
at the desired flow rate. To
pass 1,646 gallons through the
column at 14.1 gpm would take:
1,646 gallons
14. 1 gpm
117 minutes (or
about 2 hours)
During this time, the resin
column would not be processing
any water and a second column, or
water from storage will be neces-
sary to maintain supply to the
distribution system.
1,470 Ibs of salt
1 Ib of salt 8.34 Ibs of water Specific gravity of a
10 Ibs of water
gallon
10% brine solution
IV-21
-------
Step 8 - Calculation of Radium
Concentration in Regenerant Brine
From the example, calculations
showed that 1,646 gallons of
brine regenerant would be re-
quired after processing 7 days.
The raw water volume processed
during these 7 days is:
7 x 140,000 gpd -
980,000 gallons.
During the treatment of the
980,000 gallons of water, radium
will be reduced by at least
90 percent and all the radium in
the feed water could be removed.
The regeneration step will remove
the radium on the resin and
transfer it to the brine solution.
If a worst case is assumed,
100 percent of the radium is
removed in the removal as well as
the regeneration cycle, then the
concentration in the waste regen-
erant brine would be calculated
as:
(gallons feed water treated
in removal cycle) x (radium
concentration)
(gallons of regenerant)
or
980,000 gallons x 10 pCi/1 =
1,646 gallons
5,954 pCi/1
Also as a worst case, no change
in the salt concentration in the
brine is assumed. This informa-
tion can then be used in consid-
ering waste disposal options.
DESIGN OF A REVERSE OSMOSIS
TREATMENT SYSTEM FOR RADIONUCLIDES
The theory of reverse osmosis and
a description of the types of
membranes currently in use were
presented in Section III. Radio-
nuclide removals above 95 percent
have been reported in waters
treated by RO where radionuclides
have been monitored. The selec-
tion and design of an RO system
consists of evaluating the limita-
tions of the technology, including
if applicable, determining if the
water can be treated by the
reverse osmosis process, deter-
mining pretreatment requirements,
estimating the number of modules
required, and determining post
treatment needs and methods.
Analytical Requirements and Plant
Operating Information Required for
Selection of a Reverse Osmosis
System
Table 4-5 lists the analytical
data and plant operating informa-
tion necessary to determine if RO
is a viable alternative, the
pretreatment needs and the RO
system design.
Pretreatment Prior to Reverse
Osmosis
As discussed earlier in the
section on limitations of the RO
process, many materials present
in water can foul an RO membrane
or reduce performance. One or
more pretreatment steps may
therefore be required before the
RO process. The raw water anal-
ysis information, listed in
Table 4-5, will help to identify
most of the pretreatment require-
ments. Pilot tests conducted by
an RO manufacturer may indicate
needs for more or less pretreatment.
If calcium carbonate, calcium
sulfate, barium sulfate, silica
or strontium sulfate are present,
then pretreatment to reduce the
concentration of these salts may
IV-2 2
-------
TABLE 4-5
LIST OF INFORMATION REQUIRED FOR SELECTION OF A
REVERSE OSMOSIS SYSTEM
Daily water requirements, gpd
Peak water requirements, gpd
Temperature (maximum), °C
Chemical
Radionuclide concentration, pCi/1
Total hardness, (CaCO ), mg/1
Calcium hardness, mg/1
Calcium sulfate concentration, mg/1
Fluoride concentration, mg/1
Barium sulfate concentration, mg/1
Strontium sulfate concentration, mg/1
Silica, mg/1
Iron concentration, mg/1
Manganese concentration, mg/1
Total dissolved solids, mg/1
H S concentration, mg/1
Turbidity (NTU)
Silt density index
Chlorine concentration, mg/1
Bacteria MPN
Dissolved oxygen concentration, mg/1
Carbon dioxide concentration, mg/1
IV-23
-------
be required. Typical methods of
pretreatment include softening by
an ion-exchange resin to remove
the calcium, barium, or strontium
cations. Under these conditions,
the pretreatment will reduce
radium concentrations also—thereby
elmininating the need for RO for
radium removal only. pH adjustment
may be used to reduce precipitation
of carbonates on the membrane.
Precipitation is more likely to
occur at a pH above 8. Inhibitors
such as sodium hexametaphosphate
can also be used to minimize salt
deposition. Silica scaling can
also be limited by adjusting the
pH of the water to jiear pH 7
where silica exhibits its best
solubility. It is suggested that
several RO manufacturers be
contacted to determine if the
particular water will cause
scaling and what pretreatment is
recommended by each resin
manufacturer.
If iron and manganese are present
in the water supply, pretreatment
may be necessary to prevent
fouling by their insoluble oxides.
Iron oxide is most often the
major problem. Iron in ground
water is generally present as the
soluble ferrous form. As the
water contacts air, the iron will
be oxidized further to the insol-
uble ferric oxide form. The iron
can be completely oxidized by
aeration and then removed by
filtration.
Certain ion-exchange resins, such
as sodium zeolite, also effective-
ly remove iron. Iron concentra-
tions as high as 4 mg/1 can be
tolerated in the feed to the RO
module if oxygen is not present
in the water (less than 0.1 mg/1
dissolved oxygen). If dissolved
oxygen is present above 5 mg/1,
then the iron concentration
should be kept below 0.05 mg/1 in
the RO feed.
Most RO membranes are preceeded
by a 5 to 10 micron in-line
cartridge filter. This filter
prevents plugging of the RO
membrane caused by entrapment of
suspended particles.
Although RO use may be limited to
waters with SDI below 6, several
pretreatment methods will reduce
the colloidal matter in the water
and permit treatment. Nonionic
or cationic polyelectrolytes can
be added to the water to enhance
the coagulation of the fine
suspended colloidal particles and
permit removal by either sand,
anthracite, or diatomaceous earth
filters. Bench testing may be
required to evaluate performance
of various polyelectrolytes and
to select the dosage of the best
polyelectrolyte. The SDI test
should be run on a sample of the
water treated with polyelectro-
lyte to assure the water is
acceptable for treatment by RO
(SDI less than 6).
Bacteria present in the water may
affect the RO membrane either by
actual destruction of the membrane
or by fouling. Disinfectants
such as chlorine or ultraviolet
light very effectively control
bacterial growths. If the water
is chlorinated for disinfection,
then the water must be dechlori-
nated before it is applied to the
membrane as chlorine also attacks
some membrane materials, even
though membranes are available
that are chlorine-resistant. If
dechlorination is required,
passage of the chlorinated water
through a granular activated
carbon column is effective.
Hydrogen sulfide when present in
water supplies may be oxidized in
IV-24
-------
the RO process. Elemental sulfur
is a product of this oxidation
and will deposit on the membrane.
Hydrogen sulfide can be removed
by aeration, or if the problem is
severe, by chlorination, either
of which must be followed by
filtration. The adjustment of
the Ph. to values less than 7 to
prevent the precipitation of
carbonates will serve to keep the
hydrogen sulfide in the gaseous
state, which will not foul the
membranes. Aeration of the
product water removes the hydrogen
sulfide effectively, along with
the carbon dioxide formed from
the carbonates present.
Procedure for Selection of Reverse
Osmosis System for Radionuclide
Removal
There are five major concerns in
the design of an RO system for
removal of radionuclides:
1. Flow (capacity)
2. Conversion (removal
requirement s)
3. Concentration of dissolved
material in feed water
A. Feed water temperature
5. Feed water pressure
Based on this information and
assuming recommended pretreatment
is included, the RO manufacturer
can recommend an appropriate
system to remove the radionuclides
to below the MCL.
The treated flow requirements in
gallons per day should be deter-
mined from projected demands and
consideration of blending with
other water sources to achieve
compliance. A new RO module can
only exceed its specified capac-
ity by, at most, 10 percent. The
system will not treat flows above
initial rated capacity with
reliability. Additional RO
modules can be added as needed up
to the capacity of the pretreat-
ment or posttreatment systems.
Therefore, in the design of an RO
system, the pretreatment system
may be designed for supplying
several more RO modules than
initially anticipated.
Conversion is a term used to
indicate the percentage of water
flow that passes through the
membrane. Conversion depends on
the concentration and type of
dissolved materials in the waters,
as well as the membrane type and
operating pressure. Conversion
rates for other dissolved mate-
rials such as sodium chloride
also should be obtained from
manufacturer, since RO will
remove these dissolved ions and
they will be present in the
reject stream (water which does
not pass through the membrane).
The concentration of dissolved
salts in the reject stream may
restrict the disposal to a greater
extent than the radionuclides
present in this stream.
The feed pump pressure to the RO
system dictates the performance
of the membrane. Small utilities,
in most cases, will purchase the
pump and RO modules together as a
package and not separately. If
pumps are not a part of the
package the RO manufacturer will
specify pump requirements.
As discussed in Section III, the
water temperature significantly
affects the capacity of the
membrane. Initial membrane
capacity is less for lower tempera-
tures, but the rate at which
capacity is reduced is accelerated
at higher temperatures. For
example, at 15°C, the initial
IV-25
-------
capacity of a certain membrane is
74 percent of rated capacity at a
pressure of 400 psig. After the
first year, the capacity drops to
66 percent and after the second
year to 64.5 percent. At 25°C,
the initial capacity of the same
membrane at 400 psig is 100 per-
cent of rated capacity, but after
the first year, declines to
83 percent and after the second,
to 80 percent.
Specifying Reverse Osmosis Modules
Equipment vendors supply RO
systems to treat flows from as
small as a single homeowner's
system to as large as a municipal
plant supplying more than 10 mil-
lion gallons per day. Manufac-
turers can supply complete systems,
other than perhaps pretreatment
units, incorporating the necessary
design of the RO module and
auxilliary components. The
purchaser generally needs only to
provide the vendor with informa-
tion on raw water characteristics,
water demands, storage require-
ments, and space availability.
The vendor will supply the utility
or its engineer with a system
schematic, such as Figure 4-2,
and the specifications and operat-
ing ranges for all components.
The vendor will also provide a
cost estimate for his equipment
package.
Step 1 - Capacity
The utility needs to estimate the
size requirements for the RO
system based on demands and on
required radionuclide removal.
Since RO will remove 95 percent
of the radionuclides (both radium
and uranium), it is likely that
the treated water can be blended
with a portion of untreated
water. Using Figure 4-3, if a
utility had a radium concentra-
tion of 30 pCi/1, then 87 percent
of the water flow would require
treatment. Following treatment
it can then be blended with
untreated water to make up the
total demand. It should be
remembered that the volume of
water applied to an RO system is
not the output of permeate passing
through the membrane. The water
volume which does not pass through
the membrane, the reject stream,
will contain dissolved materials
including radionuclides. The
needed output from the RO system
is required for design. The
actual output of the RO system
may not necessarily depend on the
conversion rate of radionuclides
but, it may, as in the case of
water with a high salt content,
depend on the salt concentration.
The conversion rate of sodium
chloride, about 70 percent, is
less than that for radionuclides.
Hence, if the RO system is de-
signed to remove sodium chloride,
radionuclides are also removed.
The volume of water which passes
through the membrane is:
(volume, applied) x
(conversion rate).
For example, if 100,000 gallons
per day of brackish water were
applied to a membrane, the volume
which would pass through (permeate)
would then be:
(100,000 gpd) (0.70) =
70,000 gallons.
Step 2 - Calculation of Reject
Volumes and Concentration
In the operation of an RO system,
dissolved material which does not
pass through the membrane will be
present in the reject stream.
IV-26
-------
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IV-27
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IV-28
-------
The concentration of compounds in
the reject stream can be calcu-
lated using the following
expression:
(concentration in
water applied to
the membrane)
(1-conversion rate)
concentration
in reject
stream
For example, if 100,000 gpd were
applied to an RO membrane, and
the sodium chloride concentration
in this water was 1,000 mg/1,
then assuming a 70 percent conver-
sion rate for sodium chloride:
(1.000)
x = 3,333 mg/1
The volume of the reject stream
can be determined using the
following equation:
(Volume applied to membrane)
(1-conversion rate)
Example: (100,000) (1-0. 70) -
30,000 gallons.
Hence, 30,000 gallons per day of
a stream containing 3,333 mg/1 of
sodium chloride would require
disposal. The radium concentra-
tion of this stream is dependent
upon the rejection rate and the
raw water radium concentration.
If the raw water contained
30 pCi/1 radium, and radium
rejection were 95 percent, then
the radium concentration of this
stream is calculated as follows:
= (100,000 gallons)
(3.785 liters/gallon)
(30 PCi/l)(0.95)
= 10,787,250 pCi removed.
In 30,000 gallons, the concentra-
tion is then:
10,787.250 pCi
(30,000 gal)(3.785 liters/gal)
= 95 Pci/1 in the 30,000 gallons
Posttreatment
Following RO treatment the water
will be extremely soft since both
calcium and magnesium are removed
in the RO process. The water
will also contain carbon dioxide
(C09) as a result of acid pretreat-
ment to prevent CaCO incrustation
on the membrane. This
make the water acidic.
C02 will
To remove carbon dioxide, an
aerator, termed a decarbonator,
is used to strip the carbon
dioxide gas from the water and
consequently raise the water pH.
Further pH adjustment using soda
ash may be needed after decarbo-
nation. Corrosion inhibitors may
also be necessary to protect
pipes in the RO unit and in the
distribution system.
IV-29
-------
V. WASTE RESIDUE HANDLING
Each treatment process for remov-
ing radionuclides from a raw
water source generates a waste
stream of some sort. These
wastes must be disposed of in an
environmentally acceptable manner.
The purpose of this section is to
describe the characteristics of
each waste stream, to identify
the available options for disposal
of each type waste, and to sum-
marize applicable Federal Regula-
tions pertaining to disposal of
such wastes.
Most of the information presented
is based on the experience of
water treatment plants throughout
the U. S. that treat water contain-
ing radium. Radium is the only
naturally occurring radionuclide
for which a maximum contaminant
level exists under the national
Interim Primary Drinking Water
Regulations. Radium is also the
radionuclide which occurs most
often at elevated levels in
natural waters in the U. S serving
community water systems. (There
is some indication radium occurs
relatively frequently in private
individual water supplies.)
Uranium, the second most frequent-
ly occurring natural radionuclide,
has generally been shown to be
present at levels of activity
equal to or less than that of
radium. Although there are
little or no data on the radio-
activity of uranium in water
treatment plant waste streams,
the levels which may exist are
likely to be close enough to
those of radium for the discus-
sion presented in this section to
be appropriate.
The level of radiation present in
all the waste streams described
below is several orders of magni-
tude below levels which would
identify them as low-level nuclear
wastes, subject to regulation by
the Nuclear Regulatory Commission.
In fact, there are no federal
regulations which regulate the
disposal of these waste streams
based on their radioactivity.
Other characteristics, such as
the total suspended solids, total
dissolved solids, or salinity of
these waste streams are generally
the primary characteristics which
require special consideration for
their disposal.
State and local regulations
regarding handling of such resi-
dues should always be reviewed
and complied with prior to decid-
ing on any treatment alternative
for radionuclide removal.
In the absence of site-specific
data, residues should always be
measured to verify that maximum
radioactivity does not exceed
regulatory acceptable levels.
Personnel responsible for selec-
tion of a treatment alternative
for radionuclide removal must
inform themselves of all pertinent
regulations and select among the
various waste stream disposal
alternatives based on the practi-
cality and cost of each alterna-
tive. Site specific variables
such as land availability, local
geology, distance to nearest
landfill or sanitary sewer con-
nection, preclude accurate esti-
mation of disposal costs. For
further information on selection
V-l
-------
of a sludge disposal alternative,
refer to EPA Publication 600/2-77-
073, Costs of Radium Removal from
Potable Water Supplies, April 1977.
CHARACTERISTICS OF WASTE STREAMS
GENERATED BY WATER TREATMENT
PROCESSES FOR RADIONUCLIDE
REMOVAL
Lime-soda softening sludge con-
sists primarily of calcium carbon-
ate and magnesium hydroxide
solids precipitated by the treat-
ment process. Insoluble heavy
metals in trace concentrations,
including radium, are also con-
tained in the sludge. Unthick-
ened sludge ranges from 2 to
15 percent solids. This sludge
can be dewatered relatively
easily compared to alum or iron
salt sludges.
When the filters of a lime-soda
softening plant are backwashed, a
relatively dilute waste stream
results. On the average, back-
wash water volume comprises 2 to
4 percent of the total finished
product. Backwash water is
contaminated by the fine particles
trapped by the plants filters.
The concentrated salt solution
used to regenerate an ion-exchange
resin bed, backwash water, and
resin rinse water comprise the
waste stream of an ion-exchange
system. Typically, waste stream
volume will be 2 to 5 percent of
the finished water volume.
Waste products from the brine and
rinse cycle are composed primarily
of chlorides of calcium and
magnesium and the excess salt
necessary for regeneration.
Total solids in a composite
sample may vary from an average
concentration ranging from
50,000 to 100,000 mg/1 to a
maximum of 200,000 mg/1.
Reverse osmosis reject water is
generated continuously during
treatment, and typically equals
20 to 50 percent of the finished
water volume. Contaminants in
the reject stream include those
in the raw water, however, the
contaminant concentration (in-
cluding radium) may be 2 to
5 times higher.
Table 5-1 presents an estimate of
the radioactivity and quantity of
treatment waste residues for
lime-soda softening, ion exchange,
and reverse osmosis processes.
These data are based on the
experience of numerous water
treatment plants in the U. S.
which treat their source waters
for radium removal.
DISPOSAL ALTERNATIVES FOR LIME-
SODA SOFTENING SLUDGE
Alternatives for disposal of
lime-soda softening sludge,
summarized in Table 5-2, are many
and varied. Alternatives which
involve land storage or disposal
may come under the jurisdiction
of state or local authority.
Direct discharge to a navigable
waterway requires an NPDES permit.
Discharge to a sanitary sewer is
usually controlled by local
ordinance.
DISPOSAL ALTERNATIVES FOR LIME-
SODA SOFTENING BACKWASH WATERS
Lime-soda softening backwash
waters are much lower in suspended
solids and radioactivity than
lime-soda softening sludges.
Current practice at most plants
is to collect the backwash waters
V-2
-------
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TABLE 5-2
SUMMARY OF DISPOSAL ALTERNATIVES FOR
LIME-SODA SOFTENING SLUDGE
LAND APPLICATION ALTERNATIVES
- Temporary or permanent lagooning (surface impoundment)
- Sanitary landfill
a. with prior temporary lagooning
b. with prior mechanical dewatering: vacuum filtration,
centrifugation, others
- Other natural or man-made depressions (all with some dewatering
before transportation)
a. strip mine areas
b. borrow pits and quarries
- Application on farmland for soil neutralization (with or without
dewatering)
DISCHARGE ALTERNATIVES
- Direct discharge to surface receiving water
- Underground injection (aquifer recharge)
- Discharge to sanitary sewer
USE ALTERNATIVES
- Road stabilization
- Calcination and reuse in water plant
in a tank or lagoon in order to
settle most of the solids. The
settled backwash water is then
either returned to the head of
the plant for treatent or dis-
charged, either to a sanitary
sewer or navigable waterway. The
discharge alternatives are usually
regulated by NPDES (navigable
waterway) or local ordinance
(sanitary sewer).
DISPOSAL ALTERNATIVES FOR ION-
EXCHANGE BRINES
One of the problems created by
sodium cycle ion exchange softening
is the disposal of spent brine
from the regeneration cycle. In
view of increasing water pollution
control requirements, these high
salinity waters may face severe
limits on discharge.
V-4
-------
Table 5-3 summarizes the available
options for disposal of ion-
exchange brines. As always,
direct discharge options to
waterways require an NPDES permit.
Disposal in the ocean, if possible,
is a particularly attractive
alternative. Discharge to a
sanitary sewer may be difficult
due to the high salinity of the
waste unless the overall volume
discharged is small compared to
the capacity of the treatment
plant. Underground injection of
waste brines is regulated by the
Underground Injection Control
provisions of the Safe Drinking
Water Act; Federal and/or state
permits will probably be required.
REVERSE OSMOSIS WASTE
Dissolved solids rejected by the
membrane in a reverse osmosis
unit flow continuously from the
unit in a concentrated waste
stream. Because the waste is
produced continuously in large
volumes and no major additions of
chemicals are required, waste
strength (2 to 5 times the raw
water concentration) is lower
than ion-exchange brine strength.
Discharge to a sanitary sewer may
be feasible for reverse osmosis
waste. Other alternatives,
including storage, use/recovery
and disposal, are similar to
ion-exchange brine.
APPLICABLE FEDERAL REGULATIONS
Federal regulations which apply
to the disposal of water treat-
ment plant waste residue into
navigable waters, by deep well
injection, and on land are as
follows:
1. Navigable Waters—Water
treatment waste residues
discharged into navigable
waterways are regulated by
authority of the Clean Water
Act under the National
Pollutant Discharge Elimination
System (NPDES) 40 CFR 125,
129, 133, and Subchapter N.
State and/or local regulatory
agencies usually retain
regulatory jurisdiction over
such discharge through
enforcement of applicable
water quality regulations.
New or existing water plants
which discharge water residues
to navigable waters must
obtain required permits from
the local, state, and/or EPA
region in which they are
located. Generally, low-
level radionuclide content
waste residues are not
regulated differently than
other water treatment plant
discharges. It is suggested
that the state or local
regulatory agency be con-
tacted for further information.
2. Well Injection—Waste residue
which is injected underground
is regulated under authority
of the Underground Injection
Control (UIC) Program pursuant
to Part C of the Safe Drinking
Water Act and Subsequent
Regulations (40 CFR 124,
144, 145, 146). Disposal by
injection must be accomp-
lished in accordance with
state, and/or EPA regulations.
3. Land Disposal—Land disposal
of water plant waste residues
is not specifically regulated
under authority of the
Resource Conservation and
Recovery Act's Hazardous
Waste Management Program,
40 CFR 260-266.
V-5
-------
TABLE 5-3
ALTERNATIVES FOR DISPOSAL OF ION-EXCHANGE BRINES
DISCHARGE ALTERNATIVES
- Sanitary Sewer
- Receiving Waters
Streams
Ocean
DISPOSAL ALTERNATIVES
- Injection into deep aquifers
- Disposal to oil well fields
STORAGE/USE ALTERNATIVES
- Evaporation lagoons
- Sale of recovered salt
Radioactivity is not among the
characteristics which determine
whether or not a solid waste will
be considered hazardous. Solid
wastes are deemed hazardous if
they are specifically listed in
the regulation under 40 CFR 261.4
or if they exhibit the character-
istics of ignitability, corrosivity,
reactivity, and/or EP toxicity as
defined in Sections 261.20 to 24
of 40 CFR.
Radioactive wastes defined as
source, special nuclear, or
by-product materials are specifi-
cally excluded from regulation in
Section 261.4. This exclusion
does not include natural radionu-
clides normally found in potable
water treatment sludges and
brines.
Disposal of water treatment
residues containing radioactive
components can be regulated under
Nuclear Regulatory Commission
(NRC) regulations in certain
circumstances. For example, if
the radioactivity is due to
naturally occurring uranium and
has a concentration greater than
0.05 percent, it can be regulated
under 10 CFR Part 30. Similarly,
if radioactivity results from a
by-product of a commercial process
and/is in excess of approximately
10 mlcroCurie/ml, the material
can also be regulated under
10 CFR Part 30.
However, radioactivity due to
naturally occurring radium, such
as that in the sludges and brines
in question, is not subject to
NRC regulation.
Landfilling and application of
waste treatment residues are
generally under the jurisdiction
of state and local regulatory
agencies who should be consulted
to determine regulatory require-
ments prior to selection of a
particular alternative.
V-6
-------
VI. COST ESTIMATING PROCEDURES AND FUNDING SOURCES
This section provides a summary
of the kinds of costs that are
likely to be encountered in any
treatment facility construction
project and outlines a procedure
to estimate costs associated with
treatment for radionuclide removal.
It also summarizes some estimated
construction and operating cost
projections which have been made
for radionuclide removal systems.
Costs depend largely on site-
specific conditions which may
change over a period of time.
The cost estimates in this report
were based on assumptions made
when the cost curves were de-
veloped (1976-1978). In this
regard, other projects are cur-
rently in progress to refine and
improve the accuracy of cost
estimating procedures. As these
projects are completed they
should be consulted for more
accurate cost estimation
procedures.
The total cost estimate for a
water treatment facility is
generally the sum of the costs
associated with two major cate-
gories: (1) Construction Costs,
and (2) Operation and Maintenance
Costs. Each of these major cost
categories is composed of indi-
vidual costs for a number of
components. To arrive at a total
cost estimate for a given facil-
ity, the component costs are
evaluated, adjusted as necessary
for site-specific considerations
and inflation, then summed.
Costs can be expressed many ways:
annual cost, and cost per thou-
sand gallons treated are two of
the most common. The latter can
be use"d directly to estimate the
effect the project will have on
the individual consumer's water
bill. However, cost curves are
generally most useful for comparing
relative costs of treatment
alternatives and for approximating
the general cost level to be
expected for a proposed treatment
system.
CONSTRUCTION COSTS
Introduction
Whenever treatment costs are
determined, whether from a pub-
lished report or a vendor's
estimate, it is extremely impor-
tant to establish exactly what
components and processes the cost
estimate includes. Different
cost estimates based on different
basic assumptions (such as water
quality) and different components
(such as housing) have in the
past resulted in many misunder-
standings. In addition, if the
costs are taken from a report, it
is important to be sure they
apply to the size category of
your system. Once this has been
ensured, cost comparisons between
alternatives can be made using
the process outlined above. To
illustrate this procedure, the
cost information developed by the
EPA Municipal Environmental
Research Laboratory (presented in
a 4-volume report titled:
Estimating Water Treatment Costs
(EPA-600/2-79-162) can be used.
This report presents cost curves
for 99 unit processes useful for
removing contaminants covered by
the NIPDWR.
The construction cost curves
presented in this section were
VI-1
-------
developed by using equipment cost
data supplied by manufacturers,
cost data from actual plant
construction, published data, and
estimating techniques from
Richardson Engineering Services
Process Plant Construction Esti-
mating Standards, Mean's Building
Construction Cost Data, and the
Dodge Guide for Estimating Public
Works Construction Costs. The
construction cost curves were
then checked and verified by an
engineering consulting firm.
The construction cost for a
treatment facility was developed
by determining and then aggregating
the cost of eight principal
components. The components are
categorized to facilitate accurate
cost updating, which is discussed
later in this report. The cate-
gorization will also be useful
where costs are being adjusted
for site-specific, geographic,
and other special conditions.
The eight categories include the
following general items:
Excavation and Site Work. This
category includes work related
only to the applicable process
and does not include any general
site work such as sidewalks,
roads, driveways, or landscaping
which should be itemized
separately.
Manufactured Equipment. This
category includes estimated
purchase costs of pumps, process
equipment, specific purpose
controls, and other items that
are factory made and sold with
equipment.
Concrete. This category includes
the delivered cost of ready-mix
concrete and concrete-forming
materials.
Steel. This category includes
reinforcing steel for concrete
and miscellaneous steel not
included within the manufactured
equipment category.
Labor. The labor associated
with installing manufactured
equipment, and piping and
valves, constructing concrete
forms, and placing concrete and
reinforcing steel are included
in this category.
Pipe and Valves. Cast iron
pipe, steel pipe, valves, and
fittings have been combined
into a single category. The
purchase price of pipe, valves,
fittings, and associated support
devices are included within
this category.
Electrical Equipment and
Instrumentation. The cost of
process electrical equipment,
wiring, and general instrumenta-
tion associated with the process
equipment is included in this
category.
Housing. In lieu of segregating
building costs into several
components, this category
represents all material and
labor costs associated with the
building, including heating,
ventilating, air conditioning,
lighting normal convenience
outlets, and the slab and
foundation.
The construction cost curves
presented in this document are
the sum of the above cost compon-
ents, subcontractor overhead and
profit, and a 15 percent contin-
gency. These costs are based on
October 1978 dollars and can be
updated by using the Engineering
News Record (ENR) Construction
VI-2
-------
Cost Index (CCI), or Building
Cost Index (BCI). Current indices
are also published weekly in
McGraw-Hills' ENR Journal.
Historical indices are periodi-
cally tabulated in the Journal.
The following equation can be
used to update construction
costs:
Updated Cost - Cost from Curve x
(Current ENR Construction
Cost Index (CCI)
(ENR CCI when costs were
determined)
The construction cost curves used
in this document are based on
October 1978 costs when the ENR
CCI was 265.38. The ENR CCI for
June 1982 was 352.92. Thus, to
update construction cost estimates
given in this document to June 1982
costs, the given costs must be
multiplied by the ratio of:
J^'^Q. Note that the ENR CCI is
tne'average of the 20-city average
construction cost index—there is
wide variation between individual
cities and regions of the U. S.
For example, the August 1982
index varied from a low of 274 to
a high of 360 among the 20 cities,
about a 31 percent difference.
As a result, updated cost figures
using this adjustment may tend to
over or underestimate costs,
depending on construction costs
in the locality of interest.
More sophisticated cost estimating
techniques are available; they
are described in this section.
To estimate total construction
costs, several site-specific
costs must be added to the con-
struction cost obtained from the
curve: (1) special sitework,
landscaping, roads, and interface
piping between processes,
(2) special subsurface considera-
tions, and (3) standby power.
The special costs vary widely,
depending on the site, the design
engineer's preference, and regu-
latory agency requirements.
Addition of these special costs
to the aggregate cost of the unit
processes gives the total con-
struction cost.
To arrive at the total capital
cost, the following costs must be
added to the total construction
cost: (1) general contractor's
overhead and profit, (2) engineer-
ing, (3) land, (4) legal, fiscal
and administrative costs, and
(5) interest during construction.
Curves for these costs with the
exception of engineering and
land, are presented in Figures 6-1
to 6-5. A curve for engineering
cost is not included as the cost
will vary widely, depending on
the need for preliminry studies,
time delays, the size and complex-
ity of the project, and any
construction related inspection
and engineering design activities.
An example calculation of total
capital cost for an ion-exchange
treatment system is presented
later in this section.
Annualizing Capital Costs
To determine the true total
yearly cost of owning, maintaining,
and operating a radionuclide
removal system, all costs must be
stated on an annualized basis.
Operating and maintenance costs
are normally stated on this
basis. Capital costs can be
annualized as a series of equal
payments needed to recover the
initial expenditure over the life
of the treatment system, plus
interest costs.
VI-3
-------
12
11
10
8
2.5 5 10 25 50 100
TOTAL CONSTRUCTION COSTS, million dollars
Figure 6-1. General Contractor's Overhead and Fee Percentage
Versus Total Construction Cost
VI-4
-------
ADMINISTRATIVE COSTS- $
o 8
tJ l« W * 01 » «4
-------
Ml STRATI VE COSTS- $
0 O M W * « « -4OKO H W * Ol » •*•«
i !
< 6
0 4
< 3
_l 2
<
O
(/)
u: tope
j !
< 6
0 5
3 «
3
2
KXX>
)00
O
v/1
x^
' 2 34S6769
00,000 1,000,000
s
f
X
^
^
„,'
^rf*1
J ^^
t 3466 769 i
10,000,000
^^
^
X
\ 4
1C
(*
*•'
56 T
XJ.OOO
1
,oe
SUM OF CONSTRUCTION, ENGINEERING AND LAND COSTS-
Figure 6-3. Legal, Fiscal, and Administrative Costs
for Projects Greater than $1 Million
VI-6
-------
v>
I
lopoo
I
to
g 1000
o
E
ID
Q
ERES
±: 100
O 19 U
Z
JQ
8
2 346 8789 2 3456 789 2 3 4 S 8 789
10,000 100,000 1,000,000
SUBTOTAL OF ALL OTHER COSTS-$
Figure 6-4. Interest During Construction for
Projects Less than $200,000
VI-7
-------
IQCOOflOO
i,ooopoo
§
5
CD
Z
C£
O
UJ
CC
UJ
I-
KDOPOO
IODOO
1000
i
4
//
f f i
f//
100,000
3 4 5 6 7 •»
10%
8%
3 4 6 < 709
6%
6 7*9
1,000,000 10,000,000 100,000,000
SUBTOTAL OF ALL OTHER COSTS- $
Figure 6-5. Interest During Construction for Projects
Greater than $200,000
VI-8
-------
Annual payment needed to recover
the initial capital cost can be
determined by multiplying the
lump sum amount times a capital
recovery factor (CRF) as follows:
Annualized Construction Cost -
Construction Cost x CRF
The CRF is a function of the
construction loan interest
rate (i), and the life of the
treatment system (n):
CRF
id + i)
n
Many economics handbooks provide
tables of CRF values corresponding
to various combinations of interest
and project life. Table 6-1 is
an abbreviated example of this
type table. The cost example in
this section shows how tables can
be used to find the annual cost
equivalent of a proposed system's
capital cost estimate.
Example - Ion-Exchange Softening
Construction costs were developed
for pressure ion-exchange soften-
ing systems using the conceptual
information presented in Table 6-2.
The contact vessels were fabri-
cated steel, with a baked phenolic
lining added after fabrication
and constructed for 100 psi
working pressure. The depth of
resin was 6 feet, and the contact
vessel was designed to allow for
up to 80-percent media expansion
during backwash.
Facilities were sized based on an
exchange capacity of 20 kilo-
grains/ ft arid a hardness reduc-
tion of 300 mg/1. Regeneration
facilities were sized on the
basis of 150 bed volumes treated
before regeneration and a regener-
ant requirement of 0.275 Ib of
sodium chloride per kilograin of
exchange capacity. The total
regeneration time required is
50 minutes. Of this time, 10 min-
utes are for backwash, 20 minutes
are regeneration brine contact
time (brining and displacement
rinse), and 20 minutes are a fast
rinse at 1.5 gpm/ft . Feed water
was assumed to be of sufficient
clarity to require backwashing
only for resin reclassification.
Backwash pumping facilities and
resin installation are included
in the construction cost. In-,
place resin costs of $45.00/ft
were utilized.
Regeneration facilities include
two salt storage/brining basins,
which are open, reinforced con-
crete structures constructed with
the top foot above ground level.
Saturated brine withdrawal from
the salt storage/brining basins
is 25 percent brine by weight. A
salt storage of 4 days of normal
use was provided in the storage/
brining basins. Pumping facilities
were included to pump from the
brining tanks to the contact
vessels. An eductor is utilized
to add sufficient water to dilute
the brine to a 10 percent concen-
tration as it is being transferred
from the salt storage/brining
tank to the contact vessel.
Construction costs for spent
brine disposal are not included,
since they are highly site-
specific. These costs must be
added to the construction costs
presented in Figures 6-1
through 6-5.
Construction costs for pressure
ion exchange softening are pre-
sented in Figure 6-6 and summa-
rized in Table 6-3.
VI-9
-------
II
7
6
5
4
3
2
_£^^ 8
•w 7
\ 6
H- s
0 4
g •
0
gj ipoo,o(
h- 1
IO 7
O 5
0 4
3
2
KXD,0(
1
6
e
4
3
2
10,00
)0
30
0
^
i
a
^
«««^
^
^
^
^'
10,000 t S 4 6 • 7 •9100,000 2 3 4 6 6 7 •»l,000p002 346 6789
PLANT CAPACITY-gpd
100
1000
10,000
IVW -3 II
PLANT CAPACITY-m3/day
Source: EPA-600/2-79-162
Figure 6-6. Construction Cost for Pressure
Ion-Exchange Softening
VI-10
-------
n years
TABLE 6-1
CAPITAL RECOVERY FACTORS FOR SOME
COMBINATIONS OF INTEREST (i) AND PROJECT LIFE (n)
Capital Recovery Facts
6%
9%
10%
12%
5 0.237396 0.243891 0.250456 0.257092 0.263797 0.277410
10 0.135868 0.142378 0.149029 0.155820 0.162745 0.176984
15 0.102963 0.109295 0.116830 0.124059 0.131474 0.146824
20 0.087185 0.094393 0.101852 0.109546 0.117410 0.133879
25 0.078227 0.085811 0.093679 0.101806 0.110168 0.127500
TABLE 6-2
CONCEPTUAL DESIGN FOR ION-EXCHANGE SOFTENING
Plant
Capacity
(gpd)
70,000
280,000
440,000
Source:
Number of
Contactors
2
2
2
EPA-600/2-79-162.
Diameter of
Contactors (ft)
2
4
5
Housing
(ftZ)
132
210
255
Total Salt
Storage/Brining
Capacity (ft )
110
435
680
VI-11
-------
TABLE 6-3
CONSTRUCTION COST FOR ION-EXCHANGE SOFTENING
(1978 Dollars)
Cost Category
Excavation and Sltework
Manufactured Equipment:
Equipment
Resin
Concrete
Steel
Labor
Pipe and Valves
Electrical and Instrumentation
Housing
SUBTOTAL
Miscellaneous and Contingency
TOTAL
Source: EPA-600/2-79-162.
Plant
70,000
$ 320
11,360
1,700
700
1,080
5,220
9,550
18,390
7,600
$55,920
8,390
$64,310
Capacity (gpd)
280,000
$ 640
16,000
6,790
1,400
2,170
7,430
12,340
21,600
8,900
$77,270
11,590
$88,860
440,000
$ 800
18,580
10,600
1,750
2,710
8,800
13,500
23,070
9,800
$ 89,610
$ 13,440
$103,050
Construction costs for other
radionuclide control alternatives
such as reverse osmosis or lime-
soda softening can be estimated
in a manner similar to that
presented above.
OPERATION AND MAINTENANCE COSTS
To obtain a total operation and
maintenance (O&M) cost, the
individual costs for energy
(process and building heating),
maintenance material, and labor
must be determined and summed.
Total operation and maintenance
costs from a reference document
or previous contractor's estimate
can be updated and adjusted to
local conditions by updating and
adjusting cost components, energy,
labor, and maintenance material.
Energy and labor requirements are
generally provided in kilowatts
per year and hours per year,
respectively. Available cost
curves are developed by multi-
plying these requirements by the
cost of power and labor, respec-
tively. To update such a curve,
the cost per year is multiplied
VI-12
-------
by the ratio of current energy or
labor costs divided by the respec-
tive unit cost used to develop
the original cost curve. For
example, assume a particular cost
curve was developed assuming
energy costs were $0.03 per
kilowatt hour. If electricity
now costs $0.05 per kilowatt
hour, the current annual energy
cost for a given facility can be
determined by multiplying the
annual costgftorn the graph by the
rates of: v' .. An example of
this technique is provided.
Likewise, maintenance material
costs are related to the Producer
Price Index (PPI) for Finished
Goods. To update this component,
the PPI at the time the original
cost estimates were made must be
known. Then the new annual cost
is determined by multiplying the
cost from the graph by the ratio
of the new PPI divided by the PPI
at the time the graph was prepared.
The technique is also demonstrated
in the example at the end of this
section.
Example - Ion-Exchange Softening
Operation and maintenance costs
were also estimated and are
presented in this section. The
basis and assumptions used are
outlined in the following
subsection.
Ion-Exchange Operation and
Maintenance Cost
Electrical requirements are for
regenerant pumping, rinse pumping,
backwash pumping, and building
heating, lighting, and ventila-
tion. Backwash pumping was based
on a 10-minute wash period at
8 gpm/ft . Regenerant pumping
was based on a regenerant rate of
0.7 gal/min/ft of resin and a
regeneration time of 20 minutes.
Fast-rinse pumping was based on a
20-minute-rinse at a rate of
30 gal/ft of media. All pumping
was assumed to be against a
25-foot total dynamic head (TDH).
Feed water pumping requirements
are not included.
Maintenance material costs for
periodic repair and replacement
of components were estimated
based on 1 percent of the con-
struction cost. Resin replacement
costs are for resin lost annually
by physical attrition as well as
loss of capacity as a result of
chemical fouling. A 3 percent
annual loss of resin capacity
because of physical and chemical
causes is typical for cation
resins. To account for this loss
of resin and the required replace-
ment every 8 to 10 years, an
annual cost equivalent to 13 per-
cent of the resin cost is also
included in the maintenance
material. No cost is included
for sodium chloride regenerant.
Labor requirements are for opera-
tion and maintenance of the
ion-exchange vessels and the
pumping facilities. Hours were
estimated based on comparable
size pressure filtration plants
that operate automatically.
Labor requirements are also
included for a periodic media
addition and replacement of the
media every 8 to 10 years.
No costs are included for spent
brine disposal. Operation and
maintenance costs are presented
in Figures 6-7 and 6-8 and sum-
marized in Table 6-4.
Operating and maintenance costs
for other radionuclide removal
alternatives can be estimated in
VI-13
-------
Ct
UJ
u
o
1
6
S
4
3
2
10,0
1
7
6
5
4
3
2
IOC
9
e
7
6
S
4
3
Z
100
9
e
7
6
5
4
3
2
100,
1
7
6
ft
4
3
2
DO 10,
9
7
6
S
4
-f.
i
5
>of ic
:6|
: Pi 5
- *•
. UJ 4
3
t
- 100
: *
7
a
- a
4
3
t
10
000
X)0
00
0
F
<
i*
• '
/
X^
X
y
X
^
^
X
>
X
X
^
/
1
f
r
X
X
/
f
^
/
4
r
*
/
r
,
^
i
^
(
BUILDING
MAIN
L^
E
:N
ANU
MAIEfiJAL
PROC
ESJ
i E
:N
•
E
R
3
3
G
/
Y
10,000 * » 4
867 ••1,000,000
PLANT FLOW RATE- gpd
» 46t7i9
100
1000
PLANT FLOW RATE- rrT/doy
•x
-
10,000
Source: EPA-600-2-79-162.
Figure 6-7. Operation and Maintenance Requirements for
Pressure Ion-Exchange Softening - Building Energy,
Process Energy, and Maintenance Material
VI-14
-------
6
5
4
3
2
lOOp
1
6
5
4
1 2
1-
o
o IOP
e
_J •
P 6
O s
J— 4
3
2
9
6
5
4
3
2
1
7
6
8
4
I
2
00
9
7
e
s
4
I
2
00>,IO,(
LABOR- hr>
— M u « o> »-!••
- 8!
0
6
4
DOO
00
^
g
,^
,-- ^
-^*
*-—
**
-*•
^
•«
*'*
*.**
\ TOTAL
i
' LABO
. C(
R
3S*
r
10,000 t I 4 8 • 76*100,000 * ' * •• T ••1,000,000 • 488789
PLANT FLOW RATE-gpd
too idoo •» 10,000
PI ANT Fl nw RATF-m^/rtnu
Source: EPA-600-2-79-162.
Figure 6-8. Operation and Maintenance Requirements for
Pressure Ion-Exchange Softening - Labor and
Total Cost
VI-15
-------
TABLE 6-4
OPERATION AND MAINTENANCE SUMMARY FOR PRESSURE
ION-EXCHANGE SOFTENING
Plant Flow
Rate (gpd)
70,000
280,000
440,000
Maintenance
Energy (kwh/yr) Material Labor
Building
13,540
21,550
26,160
Process
140
550
870
Total
13,680
22,100
27,030
($/yr)
700
1,600
2,260
(hr/yr)
1,000
1,400
1,500
Total
Cost*
($/yr)
11,110
16,260
18,570
* Calculated using $0.03/kwh for electricity and $10.00/hr of labor.
Regenerant cost not included.
Source: EPA-600/2-79-162.
a manner similar to that pre-
scribed above.
EXAMPLE COST CALCULATION
This section presents a step-by-
step development of capital,
operating and annual costs for a
100,000 gpd pressure ion-exchange
treatment system. Conversion of
annual costs to cost per thousand
gallons is also performed. The
example is intended to illustrate
the calculations performed in any
cost estimate; i.e., the principles
of the step-by-step calculation
technique are not limited to cost
estimation for the pressure
ion-exchange treatment systems.
In this example, all costs will
be expressed in June 1982 dollars.
Calculations are rounded to the
nearest $100.
VI-16
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EXAMPLE OF COST ESTIMATING FOR A
100,000 GPD PRESSURE ION-EXCHANGE SYSTEM
STEP 1 - CALCULATE COST ADJUSTMENT FACTORS AS OF JUNE 1982
A. Construction Cost _ Current ENR CCI
Escalation Factor (CCEF) ~ Base ENR CCI
The cost curves of Reference 1 are based on October 1978 costs,
when the ENR Construction Cost Index (CCI) was 265.38. The
June 1982 ENR CCI was 352.92.
Therefore, CCEF = 352.92 _ 1.33
265.38 ~
B. Maintenance Material Current PPI
Cost Escalation Factor (MMCEF) Base Year PPI
The October 1978 Producers Price Index (PPI) issued by the U. S.
Department of Commerce, was 199.7. The June 1982 PPI was 299.4.
Therefore, MCEF = 299.4 . ,n
19977 = l'50
STEP 2 - ESTIMATE CONSTRUCTION COST USING FIGURE 6-6
From Figure 6-6, construction cost in October 1978 dollars is $70,000.
June 1982 = 70,000 x CCEF
Contruction Cost = 70,000 x 1.33
= $93,100
STEP 3 - SPECIAL COSTS
Assume that special site work for foundation pilings costs $9,000, and
that standby power requirements cost $10,000. Assume that no costs
are associated with spent brine disposal.
STEP 4 - TOTAL CONSTRUCTION COST
Construction Cost: $ 93,100
Special Cost: 19,000
Total Construction Cost $112,100
STEP 5 - CALCULATE CAPITAL COST
From Figure 6-1, general contractor's overhead and profit for a total
construction cost of $112,100 is found to be 12 percent of total
construction cost.
VI-17
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Assume that engineering fees are 10 percent of total construction cost
and general contractor's overhead and profit, and that land costs are
$30,000. Calculate the sum of total construction, general con-
tractor overhead and profit, engineering and land costs.
Total Construction $112,100
General Contractor Overhead and
Profit, 0.12 (112,100) 13,500
Subtotal 125,600
Engineering at 10%, 0.10 (125,600) 12,600
Subtotal 138,200
Land 30,000
SUBTOTAL $168,200
From Figure 6-2, legal fiscal and administrative costs are found to be
$5,000. Assume that interest paid on the construction loan will be
10 percent per annum. From Figure 6-4, interest during construction
is $4,000. Calculate total capital cost:
Subtotal of Other Costs $168,200
Legal, Fiscal, and Administrative Costs 5,000
Interest during Construction 4,000
TOTAL CAPITAL COST $177,200
STEP 6 - ESTIMATE ANNUAL OPERATING AND MAINTENANCE COST
A. Energy Cost
Energy Use - Process Energy + Building Energy*
* Building energy is very dependent on climate. If possible,
estimate directly for your area.
B. Maintenance Material
From Figure 6-7, October 1978, annual maintenance material cost
is $850.
June 1982 = $850 x MMCEF
Maintenance Material = $850 x 1.50
Cost - $1,300
From Figure 6-7,
Energy Use - 14,200 kwh/yr +
2,000 kwh/year
» 16,200 kwh/year
Energy Cost/year » kwh/year x energy cost
kwh
VI-18
-------
For this example, assume energy cost of $0.05/kwh
Energy cost/year = 16,200 x $0.05
= $810
C. Labor Cost
From Figure 6-8, labor = 1,200 hr/yr for a 100,000 gpd system. If
labor costs $12.00/hr (including fringe costs), annual labor cost
is calculated as follows:
Annual labor cost = 1,100 hr/yr x $12.00/hr
= $14,400
D. Regenerant (Salt) Cost
Assume that the ion-exchange resin manufacturer has calculated
that:
250 Ibs of salt per 100,000 gal treated water are required for
regeneration, and that salt costs $0.03/lb.
o «. j inn nnr, -, /j 250 IbSSalt $0.03
Cost per day = 100,000 gal/day x 100tQOO gal x j^^
= $7.50/day
Cost per year = 365 days/yr x \ = $2,800/year
E. Total Annual O&M Cost
Energy $ 800
Maintenance Material 1,300
Labor 14,400
Salt 2.800
Total Annual O&M Cost $19,300
STEP 7 - ANNUALIZE CAPITAL COST
If the cost of money is 10 percent, and the system has a 20-year
design life, the annualized capital cost is computed as follows:
Annualized Capital Cost - Capital Cost x Capital Recovery Factor at
interest rate of 10 % for 20 years
The capital recovery factor from Table I for 10 percent and 20 years
is 0.117460
Annualized Capital Cost - $177,200 x 0.007460
= $20,820
VI-19
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STEP 8 - CALCULATE TOTAL ANNUAL COST AND COST PER 1,000 GALLONS TREATED
A. Annual Cost Calculation
Annuallzed Capital Cost - $20,820
Total Annual O&M Cost = $19.300
Total Annual Cost = $40,120
B. Annual Treated Flow, Thousands of Gallons
Annual Treated 100,000 gal 1 -,,-
Flow (1,000 gal) " day x 1,000 x
= 36,500 thousand gallons
C. Cost per 1,000 Gallons Treated
Annual Cost
Cost/1,000 gal
Annual Treated Flow (1,000 gal)
$40,120
36,500 thousand gallons
Cost/1,000 gal - $1.10
FUNDING SOURCES
The principal financing options
to small water systems for treat-
ment process improvement for
radionuclide removal can be
categorized as follows:
o Self-Financing
- User charges and fees
- Bonding/loans
o Direct Grant Programs
o Subsidized/Assisted Loan
Programs
o Other Assistance Programs
- Labor sharing with
other systems
- EPA technical assistance
activities
These are discussed in turn as
follow.
Self-Financing
Water utilities process, deliver
and charge consumers for potable
water. In this, they bear close
resemblance to other businesses
that also produce and sell a
product. Most of these utilities,
publicly or privately owned, do
not normally have problems in
financing needed capital improve-
ments either through user fees or
changes in the water rate, or by
bonding. However, the financing
needs for constructing and oper-
ating radionuclide removal systems
may severely strain small community
water systems, either by requiring
capital expenditures beyond their
ability to finance, or by causing
very large incremental increases
in user charges. The latter
course may incur substantial
VI-20
-------
consumer resistance to the improve-
ment program, a major impediment
in the case of publicly owned
systems. Very small systems may
be particularly vulnerable to
problems in this regard—one
study indicates that up to 30 per-
cent of systems serving less than
500 people may be unable to
finance radionuclide removal
unassisted.
The prime considerations for
self-financing include the
following:
o Amount of revenues available
for payment of interest costs
o Ratio of new treatment
capital costs to existing
assets
o Percent rate increase needed
to finance and operate
treatment
o Ratio of the typical resi-
dential water bill to the
community's median family
income
In competing for funds on the
private capital markets, the larger
utility is expected to have a
debt service ratio (ratio of
income after operating expense to
interest costs) of 1.3 and income
at least twice that of interest
charges. Private utilities must
be showing a net profit, after
taxes, of 10 to 13 percent. User
bills should run less than 1.5 to
2.0 percent of median family
income.
Smaller utilities may be substan-
tially less robust financially,
and still be able to raise money
locally. Utility customers may
be willing and able to put up the
needed capital. Even so, the
utility should have a debt service
ratio of at least 1.0 so interest
and bond repayment schedules can
be met.
Grant Programs
The principal financial assistance
program available to small commun-
ity water system (public or
private nonprofit) is operated by
the Farmers Home Administration
(FmHA) of the Department of
Agriculture. FmHA can grant up
to 75 percent of the cost for
installation, repair or upgrading
community water systems that
serve fewer than 10,000 people
with emphasis on farmers and
other rural residents.
Program aid priorities are as
follows:
o Public bodies and towns with
emphasis to those serving
5,500 people or less
o Assist compliance with Safe
Drinking Water Act
o Low income communities
o Systems proposing to merge
and/or regionalize
o State recommended projects
o Projects promoting water
energy conservation
Principal grant award criteria
are:
1. User charges must be at
least equal to other similar,
already established systems,
on the basis of:
o Similar costs of con-
struction and operation
o Similar economic conditions
2. Debt service costs exceed
net levels as determined by
the ratio of mean family
cost for water service to
median family income.
Specifically:
o For communities of
median family income
less than $6,000 debt
VI-21
-------
service mist exceed
0.75 percent of median
family income to be
eligible.
o For communities of
median family income
$6,000 to $10,000, debt
service/income must
exceed 1.0 percent for
eligibility.
o For communities exceeding
$10,000 median family
income, debt service/in-
come must exceed 1.25 per-
cent for eligibility.
FmHA can be contacted for further
information at any one of
340 offices nationwide.
The Economic Development Adminis-
tration (EDA) has some limited
programs for water/sewer assist-
ance, primarily keyed to promoting
industrial development and creating
jobs. Grants can range from
50 to 80 percent of project costs
(up to 100 percent for Indian
Tribes) and public or private
nonprofit agencies may qualify.
EDA has six regional offices and
staff in each of the 50 states.
Direct Loan Programs
Three federal agencies operate
direct loan programs:
o Department of Interior - has
two programs available to
public nonfederal entities
in the 17 western states.
o Farmers Home Administration -
has loan program with similar
criteria to those used in
their grant program. The
loan can be for 100 percent
of the project cost.
Small Business Administra-
tion - has a number of loan
programs that may be used by
small investor-owned water
utilities. Loans cannot
exceed $150,000.
Loan Guarantee Programs
Both the Small Business Administra-
tion (SBA) and the Farmers Home
Administration (FmHA) can provide
backing for privately placed
loans as follows:
o SBA - will guarantee up to
90 percent of a loan up to
$500,000 for private, inde-
pendent businesses that are
refused a bank loan.
o FmHA - has a Business and
Industry Loan Program avail-
able to public or private
organizations, particularly
those located in rural areas
and serving fewer than
2,500 persons. Loan guaran-
tees range up to 90 percent
of face value.
Other Forms of Assistance
Other ways of reducing financing
and/or operating costs include
the following:
o Bond banks - Several states
have central bond banks that
assist localities in the
mechanics of bond financing.
By aggregating small bonds
into larger ones, interest
costs may be reduced and
bond placement enhanced.
o Research and development -
The U.S. Environmental
Protection Agency (EPA) has
funded pilot and demonstra-
VI-22
-------
tlon projects for water and
wastewater systems using
uncommon technology.
State loan programs - Several
states provide direct loans
for contruction of public
water and sewer projects.
The programs are normally
operated under the aegis of
state economic development
offices.
Shared operator costs with
other nearby utility(s) -
Ion exchange radionuclide
removal does not require
full time supervision;
hence, operator costs could
be divided up between two or
more utilities where travel
distance permits. (Region-
alization is one approach to
shared operating expenses.
VI-23
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VII. OPERATION AND MAINTENANCE
An operator is defined as any
person, including the owner, who
is in actual charge of the opera-
tion, supervision, or maintenance
of a water purification plant.
Most water plant operators will
not have the training required
for radionuclide removal, partic-
ularly for the treatment processes
of lime softening, reverse osmosis,
or ion exchange. Therefore,
on-the-job training will be
necessary and will rely on exten-
sive help from the equipment
manufacturer and/or the design
engineer.
On-the-job training complemented
by formal training programs are
best for the processes described
above. Information on short
courses and seminars is available
from the state certification and
training office or the Board of
Health or equivalent agency in
any given state. Organizations
such as the American Water Works
Association and the Rural Water
Association also conduct training
programs and can provide informa-
tion about local programs.
The operator should be reasonably
proficient in plumbing and elec-
trical skills and have an under-
standing of the operation and
repair of simple pumps, valves,
water meters and electrical
controls fundamental to success-
ful operation and maintenance.
He or she must be capable of
carrying out a program of periodic
sampling and be able to use a
packaged test kit for alkalinity
and hardness as well as be able
to use a pH meter and conduct
total dissolved solids tests.
The operator will need to be
knowledgeable of sampling tech-
niques for radionuclides but will
not likely be required to be able
to analyze for them. A working
knowledge of fundamental chemistry
will be essential. The operator
will be required to make simple
calculations and record results.
The operator should also be of
sufficient intelligence and
schooling so that he or she can
be trained in the fundamentals of
process operation and be able to
fully grasp the importance of
avoiding excessive radionuclide
concentrations in the finished
water.
Operator time requirements are
dependent on system size and may
be regulated by the states. In
general 2 to 3 hours per day will
be necessary in order to ensure
everything is working properly
and to carry out sampling (moni-
toring) and maintenance procedures.
MANPOWER REQUIREMENTS
For plants processing less than
0.5 MGD, it is generally recom-
mended that one certified operator
be in charge of the operation of
a lime-soda softening plant,
reverse osmosis, or ion-exchange
system. While no federal require-
ments exist for operator certifi-
cation, state requirements do.
These requirements vary from
state to state, however, so the
state regulatory agency should be
consulted.
To assist the operator in sampling,
lubricating, cleaning, maintenance,
and general housekeeping, a
VI I-1
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Maintenance Helper or semi-
skilled laborer may also be
required. This position may be
part-time depending on the design
flow, actual equipment installed,
and local conditions.
MANAGEMENT AND RECORD KEEPING
The operator's management responsi-
bility generally includes running
the facility within acceptable
state and local guidelines and
within an approved operating
budget. Specific responsibil-
ities are listed in the Appendix.
Only through concise and accurate
reporting of occurrences and
accomplishments will past experi-
ence be helpful in handling
future operational situations.
Complete records are necessary
for interpreting the results of
the treatment process. In the
event of legal questions pertain-
ing to water quality, records are
required as evidence of what
occurred at any given time or
over a certain time period.
Various local, state, and federal
regulatory agencies also receive
water quality reports.
Records also provide an excellent
checklist on current and future
work, especially maintenance
tasks. Well-kept records should
note when service was last per-
formed on each piece of major
equipment and when future service
will be required.
Financial records are necessary
to enable an accurate budget to
be prepared for the plant.
Financial records also will
indicate possible process or
operational changes whereby the
cost of efficiently handling
various unit processes may be
reduced*
The following records are consid-
ered necessary for efficient
operations:
1. Daily operating logs,
2. Monthly operating report,
3. Reports to state agencies,
4. Reports to federal agencies,
5. Annual report, and
6. Maintenance records.
Daily operating logs usually
include: (1) public complaints,
(2) facility visitors, (3) person-
nel injuries, (4) alarm status
reports, (5) routine operational
duties, and (6) unusual operation
and maintenance conditions.
The equipment manufacturer will
normally illustrate the specific
maintenance records to be kept.
The following records, as a
minimum, should be readily avail-
able at the plant:
1. As-built engineering drawings,
2. Copy of construction
specifications,
3. Equipment supplier's opera-
tion and maintenance manuals,
4. Piping and wiring diagrams,
5. Construction photographs (if
available),
6. Lubrication records, and
7. Major repair history.
These records should be periodically
reviewed and updated when warranted.
Lists of purchases and expenses
during the fiscal year should be
kept up to date and comparisons
should be made with budget alloca-
tions to avoid excess expeditures.
The major categories of financial
expenditures are labor, utilities,
chemicals, and facility supplies,
and can be broken down as follows:
VI1-2
-------
Labor
Operations
Administration
Maintenance
Utilities
Chemicals
Electricity Chlorine
Facility Supplies
Laboratory chemicals
Fuel
Lime,
soda-ash Cleaning materials
Telephone Caustic soda Maintenance supplies
Potable Water Sulfuric acid Spare parts
Polymers
Other
necessary
chemicals for
treatment
process
Other expendable
items
A systematic filing arrangement
of all records to eliminate the
possibility of loss and deterior-
ation and to permit ready access
and prompt location of specific
data is an essential part of a
complete laboratory records
system.
To enable record keeping to be
neat and legible, forms should
also be provided and used. A
ball-point pen or a pencil hard
enough to resist smudging should
be used in recording data on the
various forms. Neat, legible
data will greatly reduce the
number of errors in data compila-
tion and subsequent use.
EMERGENCY PROCEDURES
Emergency conditions generally
result from either natural or
manmade causes. The primary
concern during a natural disaster
should be the safety of plant
personnel and the integrity of
the water quality. Temporary
failure to remove radionuclides
will be of secondary importance
at times when there is no water
being produced by the plant or
when there is a lack of disinfec-
tion capability. Therefore, the
plant operator's actions in a
recovery phase^ will be: first,
to restore water pressure, and
secondly to restore the
disinfection.
Specific emergency equipment
procedures are available from the
manufacturers. By reviewing
these procedures periodically,
the operator will be ready to
respond as needed. Examples
would include emergency power
generation or auxiliary direct-
drive engines, adequate water
supply and pressure to the chlori-
nators and extra sampling of the
system for bacteriological
monitoring.
SAFETY PROCEDURES
Without adequate safety precau-
tions, the operation of any water
plant is a dangerous occupation.
VI I-3
-------
Radionuclide removal systems may
use moving mechanical equipment,
electrical motors and switchgear,
caustic and acidic chemicals, and
chlorination equipment, all of
which require a basic understand-
ing of safe practices.
Good housekeeping is an important
factor in plant safety. All
equipment and structures should
be kept orderly and in good
repair. Walkways should be
guarded with handrails and free
from oil and grease. By careful
use of equipment only as it is
intended to be used, accidents
can be minimized. Special pre-
caution should be taken near
electrical and mechanical equip-
ment. Examples follow:
1. The manufacturers' instruc-
tions regarding the proper
operation and maintenance
procedures for each piece of
mechanical equipment in the
facility should be followed.
When working on a piece of
mechanical equipment, all
power to the equipment
should be shut off by opening
the proper control switch
locking it out, and tagging
it to prevent others from
closing it. Never attempt
to perform preventive or
corrective maintenance on
machinery that is operating,
unless directed otherwise in
the manufacturers' instruc-
tion manual and verified by
your own evaluation of the
site-specific conditions.
2. Do not perform work on a
piece of electrical equipment
while standing on a wet or
damp floor. A rubber mat
should be placed on the
floor in front of electrical
panels as an added precaution.
Do not use metal ladders
around electrical equipment,
and only use properly grounded
electrical tools.
3. Post emergency telephone
numbers at each plant tele-
phone. Also post numbers
for chemical equipment
suppliers and manufacturers.
In case of emergency, contact
the owner, and state regula-
tory agency.
MAINTENANCE PROCEDURES
The specific maintenance functions
will be described by the equipment
manufacturers and will include
duties not required of every
operator because specific equip-
ment may require certain skills
or tools.
General maintenance for the three
types of systems proposed for
radionuclide removal are given
below:
1. Maintenance for Reverse
Osmosis (RO) Systems
2. Maintenance for Ion Exchange
Systems
3. Maintenance for Lime (Soda)
Softening Systems
Maintenance for Reverse Osmosis
Systems
Since the RO membrane literally
filters water, the membrane is
sensitive to clogging with particu-
late material, iron, manganese,
turbidity, organic substances and
certain other undissolved impuri-
ties in the water. Therefore,
considerable attention has to be
given to the pretreatment require-
ments for RO membranes in the
design and selection of equipment.
VI1-4
-------
Nevertheless, there will still be
the need to periodically clean
the membranes.
The method used for cleaning will
depend on the type of membrane
used and specific manufacturer's
suggestions, however, the most
common techniques used are foam
ball swabbing and flushing with
chemical additives at low
pressure.
The cleaning schedule or frequency
will vary from system to system
depending on the nature of the
water being treated. The symptoms
of operation that dictate cleaning
the membranes are any one of the
following:
- excessive pressure drop
across the membrane
(20-50 psi above the orig-
inal pressure drop of
start-up)
- excessive decline of permeate
flow
- increasing total dissolved
solids in product water or
excessive radionuclide
passage.
Other maintenance associated with
RO systems would involve the
following items of major equipment:
1. high pressure pump
(400-600 psi)
2. high pressure valves and
seals
3. chemical feed pumps
4. chemical feed make-up and
s torage
5. reject water disposal
systems
6. normal maintenance associ-
ated with storage tanks,
system service pumps, and
chlorinators.
Maintenance for Ion Exchange
Systems
Typical preventive maintenance
checks:
o Pumps (if any):
- Overheating. The pump
motor should not burn the
hand when touched or smell
hot.
- Noisiness/vibration.
Rattling and grinding
noises may indicate serious
bearing problems and/or
shaft misalignment.
- Water leaks from packing
glands and fittings.
- Loose hardware, mountings,
electrical connections.
- Surface rusting/corrosion.
- Motor ventilation ports.
Ports should be clear and
free of dirt, oil and
moisture.
o Motorized flow valves:
- Water, oil leaks.
- Rough operation, noisiness
during regeneration cycle.
- Leaks from waste line when
valve is in the "off" or
"in service" position.
- Proper valve positioning.
o Flow meters/flow totalizers:
- Comparison of main flow
meter and check flow meter
for equivalent recordings.
- Leaking, moisture under
meter glass, sticking of
meter in operation.
o Blending flow valve/flow
meters:
- Check daily for correct
flow splitting.
VI I-5
-------
o Brine/salt storage:
- Salt level in brine tank.
- Stored salt quantity.
o Tanks, pipes and appurtenances:
- Leaks, cracks, corrosion.
Checks During Regeneration
o Check time clock and relays
for:
- Noisiness
- Sticking
- Overheating or hot smell
- Time accuracy
o Check automatic valve for:
- Leaking
- Sticking
- Complete cycling
o Check brine system for:
- Flow meter operation
- Adequate salt in brine
tanks
o Waste flow:
- Free flowing
- Evidence of resin in waste
flow
Other Periodic Acitivities
o Pumps/motors:
- Lubricate per manufacturer's
recommendation
o Flow meters:
- Calibrate per manufacturer's
recommendation
Time clock/relays/automatic
valve:
- Lubricate, adjust per
manufacturer's
recommendation
Maintenance for Lime-Soda Softening
Systems
Maintenance of this equipment
involves at least twice yearly
draining the clarifier structure
for cleaning and to remove scale.
The turbine or mixer sludge rake
arms (if applicable) should also
be checked for clearance and
operation.
The chemical feed systems - such
as lime slurry will need daily
inspection to remove sediments
that may settle out and clog the
piping. The chemical feed pumps
should be calibrated at least
once a week to ensure reliability
of feeds. Caution must be used
when working with the lime slurry
feed system since the solutions
are caustic and will cause skin
burns.
Filters associated with these
plants will have to be maintained
by proper backwashing and cleaning
in order to prevent mud-ball
formation in the media and to
ensure good consistent turbidity
removals. Normally filters are
washed on a head loss or effluent
turbidity monitoring basis de-
pendent on type. Typical filter
hours for softening plants are
40 to 150 hours between back-
washes. Any electrical or hydro-
pneumatic controls associated
with these units should be cali-
brated and maintained at least
quarterly.
VI1-6
-------
VIII. CASE HISTORIES
This section presents a case
history for each method of radio-
nuclide removal described earlier,
including:
1. Lime-soda softening,
2. Ion exchange and blending of
treated and untreated water,
and
3. Reverse osmosis.
LIME-SODA SOFTENING
The water treatment plant in
Peru, Illinois, is an example of
a small plant which treats a raw
water having an Ra-226 concentra-
tion which exceeds the MCL of
5 pCi/1. The raw water is pumped
from three wells. Treatment
consists of aeration, addition of
lime and soda ash, clarification,
sedimentation, chlorination, and
filtration. Full treatment is
provided to 60 percent of the raw
water which is then blended with
40 percent, which is filtered but
not softened. An average of
1.8 MGD is processed by the
treatment plant and pumped to the
distribution system. Treatment
system design criteria and oper-
ating data are presented belowj
Aerator
Type: Coke tray with forced
draft 2
Area: 324 ft
Capacity: 1,620 gpm
Lime and Soda Ash Addition
Average amount of lime added:
1.87 lb/1,000 gal
Average volume of soda ash
added: 0.008 gal/1,000 gal
Clarifier
Dimensions: 30-ft diameter,
14-ft depth
Volume: 74,000 gal
Weir Loading Rate: 14 gpm/ft
Settling Tank
Dimensions: 36 ft x 30 ft x
14.5 ft (Tank 1)
16 ft x 20 ft x
14.5 ft (Tank 2)
Total Volume: 152,000 gal
Recarbonator
Dimensions: 14.5 ft x 5 ft x
12 ft
Volume: 6,510 gal
Gas Chlorinator
Capacity: 50 Ib/day
Source: 150 Ib cylinder
Filters
Number of Units: Three
Type: Gravity rapid^sand
Filter Area: 170 f£
Capacity: 2 gpm/ft
Table 8-1 presents reduction data
for Ra—226 and hardness for
3 days of sampling. These data
show the radium removal is above
70 percent with an effluent
radium concentration below 2 pCi/1.
The chemical cost (lime and soda
ash) for this plant is approxi-
mately $75 per day, which is
$0.04 per 1,000 gallons based on
the treated flow of 1.8 MGD. The
construction cost for this plant,
VIII-1
-------
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H
H
0
1
d
o
•H
4-1
U
3
1
d
CU
CJ
Q)
CL,
C
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4-1
3
CO
co
cu
d
•g
rt
!B
vO
CM
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|
CO
co
cu
d
^j
cd
33
vO
CM
CM
1
cd
/—\
CO
O
CJ
cd
CJ
co
cd
"**^
00
>E
y*^
f— |
^x^
•H
CJ
x2?
CO
o
CJ
cd
CJ
CO
cd
rH
00
J,
Q1
•^^^
•H
QJ
a
00
e
T-
r™
D
E
V.
cu
4-t
'o
oo o
C*s. * «
. OO vO
00 ^O vO
fs».
vO CT^
^" • •
o r>.
CM r-» r^
cy*
o o CM
1^ O rH
i— | f~\
00 fH •-!
-------
as well as other operating costs,
are not available.
ION EXCHANGE AND BLENDING OF
TREATED AND UNTREATED WATER
The village of Lynwood, Illinois,
has an ion-exchange water treat-
ment plant which treats an average
of 158,000 gpd. This plant
removes hardness and Ra-226 from
the raw water which is pumped
from a deep well. Treatment
consists of ion exchange, using a
styrene-based zeolite resin, and
chlorination. Approximately
90 percent of the raw water
receives ion-exchange treatment
and is blended with 10 percent of
the raw water prior to chlorina-
tion. Design criteria for this
treatment system are presented in
the following lists:
Ion-Exchange Units
Number of Units: Three
Dimensions: 90-in diameter,
7.5-ft height
Resin Volume in Each Unit:
206 ft
Bed Depth: 53 in .
Resin Capacity: 11 kgrCaCO /ft
Total Capacity (per units):
2,266 kgr
Gas Chlorinator Capacity:
100 Ib/day
Source: 150-Ib cylinder
Table 8-2 presents Ra-226 reduc-
tion data for 3 days of sampling.
Radium removal is shown to be
above 97 percent producing a
softened water with a radium
concentration of less than
0.5 pCi/1.
TABLE 8-2
Ra-266 REDUCTION, LYNWOOD, ILLINOIS
Sampling
Date
Ra-226 Concentration* (pCi/1) Percent
Raw Softened* Reduction
3/27/75
4/02/75
4/10/75
14.80
14.70
14.90
0.26
0.36
0.27
98.2
97.6
98.2
* Samples collected midway between regeneration of resin.
+ Following ion-exchange treatment.
Source: EPA, ORP/TAD-76-2.
VIII-3
-------
The construction cost of this
ion-exchange treatment plant, as
built in 1972, was $150,000. The
operating cost is approximately
$1,520 per month, which is
$0.32 per 1,000 gallons of treated
water based on a flow of
158,000 gpd. The operating cost
does not include amortization of
the construction cost.
The construction cost of this re-
verse osmosis treatment plant,
built in 1975, was $70,000. The
estimated operating cost is
$1.22 per 1,000 gallons of treated
water, based on a flow of 5,000 gpd.
The operating cost does not
include amortization and membrane
replacement.
REVERSE OSMOSIS
The reverse osmosis treatment
plant which provides potable
water for the Sarasota Bay Mobile
Home Park in Sarasota County,
Florida, is a good example of a
small plant treating a raw water
with a high Ra-226 content. Raw
water is pumped from a well and
pretreated by the addition of
hydrochloric acid for pH adjust-
ment and sodium hexametaphosphate
as a sequestering agent. The
pretreated water is then pumped
through the reverse osmosis
units, which are equipped with
hollow-fiber membranes, at an
operating pressure of 400 psi.
Posttreatment consists of aera-
tion, after which the water is
chlorinated. No blending is
conducted at this plant. The
average flow through the plant is
5,000 gpd.
The average hardness and Ra-226
concentrations in the raw water
are approximately 1,612 mg/1 (as
CaCO ) and 20.5 pCi/1, respec-
tively. The treated water con-
centrations of hardness and
Ra-226 are approximately 34 mg/1
(as CaCO ) and 0.32 pCi/1, re-
spectively. This represents a
97.9-percent removal for hardness
and a 98.4-percent removal for
Ra-226. These data are based on
sampling, conducted from March
through April 1977.
VII1-4
-------
BIBLIOGRAPHY
AWWA Buyers' Guide. 1980. American Water Works Association Journal.
72(11):Part 2.
Bennett, D.L. 1978. The Efficiency of Water Treatment Processes in
Radium Removal. AWWA Jounral. 70(12):698-701.
Department of Naitonal Health and Welfare. Emergency Health Services.
1963. Control of Radioactive Fallout in Water Systems, A Manual
for Water Engineers. Ottawa, Ontario, Canada.
DuPont Company. 1976. Permasep Permeator Engineering Design Manual.
Wilmington, Delaware.
Equipment Buyers' Guide Issue. 1979. Chemical Engineering.
86(15):Part 2.
Gloyna, E. F., Ledbetter. 1969. Principles of Radiological Health,
Mercel Dekker, New York.
Illinois State Department of Public Health and the University of Illinois.
1960. Radiological Aspects of Water Supplies. Proceedings of the
Second Sanitary Engineering Conference. University of Illinois
Circular. Urbana, Illinois.
Oak Ridge National Laboratory. Health Physics Division. ND. Report of
the Joint Program of Studies on the Decontamination of Radioactive
Wastes. ORNL-2557, Radioactive Waste, TID-4500 (14th ed).
Permutit Company, The. 1943. Water Conditioning Handbook. The Permutit
Company, New York, New York.
Petersen, N.J., Samuels, L.D., Lucas, H.F., and Abrahams, S.P. 1966.
An Epidemiologic Approach to Low-Level Radium 226 Exposure. Public
Health Reports, 81(9):805-812.
Sebesta, F., Benes, P., Sedlacek, J., John, J., and Sandrik, R. 1981.
Behavior of Radium and Barium in a System Including Uranium Mine
Waste Waters and Adjacent Surface Waters. Environmental Science
and Technology. 15(1):71-75.
Smith, S.E. and Garrett, K.H. 1972. Some Recent Developments in the
Extraction of Uranium from its Ores. The Chemical Engineer.
pp. 440-444.
Sorg, T.J. 1978. Treatment Technology to Meet the Interim Primary
Drinking Water Regulations for Inorganics. AWWA Journal.
70(2):105-112.
-------
BIBLIOGRAPHY
(Continued, Page 2 of 3)
Sorg, T.J., Forbes, R.W., and Chambers, D.S. 1980. Removal of Radium-226
from Sarastoa County, Fla., Drinking Water by Reverse Osmosis.
AWWA Journal. 72(4):230-237.
Sorg, T.J., Logsdon, G.S. 1980. Treatment Technology to Meet the
Interim Primary Drinking Water Regulations of Inorganics: Part 5.
AWWA Journal. 72(7):411-422.
Thompson, W.E., Swarzenski, W.V., Warner, D.L., Rouse, G.E., Carrington,
O.F., and Pyrih, R.Z. 1978 Ground-Water Elements of In-Situ Leach
Mining of Uranium. Prepared by: Geraghty & Miller, Inc. Prepared
for: Nuclear Material Safety and Safeguards, Division of Fuel
Cycle and Material Safety.
Trace Metal Data Institute. 1978. Industrial Application of Reverse
Osmosis Technology: Optimizing Performance. Bulletin 608. El
Paso, Texas.
Trace Metal Data Institute. 1980. Utilization of Anti-Scalents to
Facilitate Increased Reverse Osmosis Water Reclamation from Indus-
trial Waste Streams. Bulletin 602. El Paso, Texas.
United States Environmental Protection Agency. 1977. Costs of Radium
Removal from Potable Water Supplies. Cincinnati, Ohio.
EPA-600/2-77-073.
United States Environmental Protection Agency. 1980. Environmental
Protection Agency National Interim Primary Drinking Water Regula-
tions. Federal Register, 40(141):132:0101-0104.
United States Environmental Protection Agency. Drinking Water Research
Division. 1979. Estimating Water Treatment Costs, Volumes 1, 2,
and 3. Cincinnati, Ohio. EPA-600/2-79-162a,b,c.
United States Environmental Protection Agency. Office of Radiation
Programs. 1976. Determination of Radium Removal Efficiencies in
Illinois Water Supply Treatment Processes. Cincinnati, Ohio.
ORP/TAD-76-2.
United States Environmental Protection Agency. Office of Radiation
Programs. 1979. A Study of Radon-222 Released From Water During
Typical Household Activities. Eastern Environmental Radiation
Facility. Montgomery, Alabama.
United States Environmental Protection Agency. Office of Research and
Development. 1977. Manual of Treatment Techniques for Meeting the
Interim Primary Drinking Water Regulations. Cincinnati, Ohio.
EPA-600/8-77-005.
-------
BIBLIOGRAPHY
(Continued, Page 3 of 3)
United States Environmental Protection Agency. Office of Water Supply.
1976. National Interim Primary Drinking Water Regulations. Wash-
ington, D.C. EPA-570/9-76-003.
United States Environmental Protection Agency. ND. Methods of Removing
Uranium From Drinking Water. Work sponsored by the Office of
Drinking Water under Interagency Agreement No. EPA 79-D-X0674. Oak
Ridge National Laboratory. Oak Ridge, Tennessee.
United States Envrionmental Protection Agency. 1981. Criteria and
Standards Division. 1981. Radioactivity in Drinking Water.
Washington, DC. EPA 570/9-81-002.
United States Environmental Protection Agency. 1981. Uranium in U.S.
Surface, Ground and Domestic Waters, Volume I. Work sponsored by
the Office of Drinking Water under Interagency Agreement No.
EPA 79-D-X0674. Oak Ridge National Laboratory. Oak Ridge,
Tennessee.
United States Geological Survey. 1981. Data on Ground-Water Quality
with Emphasis on Radionuelides, Sarasota County, Florida. Open-File
Report 80-1223.
Webster's New Collegiate Dictionary. 1980. Editor in Chief: Henry
Bosley Woolf. G&C. Merriam Company, Springfield, Massachusetts.
-------
OTHER SUGGESTED READING
Costs of Radium Removal From Potable Water Supplies, USEPA,
EPA-600/2-77-073, April 1977, and Manual of Treatment Techniques
for Meeting the Interim Primary Drinking Water Regulations, USEPA,
EPA-600/8-77-005. April 1978.
Drinking Water and Health, Safe Drinking Water Committee. 1977. National
Academy of Sciences, Washington, DC 20006.
Known Effects of Low-Level Radiation Exposure. April 1980. U.S. Depart-
ment of Health, Education, and Welfare, Public Health Service,
National Institutes of Health, NIH Publication No. 80-2087.
Natural Background Radiation in the United States, 1976, National Council
on Radiation Protection and Measurements, (NCRP) Publication #45,
Washington, DC 20014.
-------
APPENDIX A
CHEMICAL ELEMENT SYMBOLS
AND
ATOMIC NUMBERS
-------
Chemical element symbols and atomic numbers
Chemical
Element
Actinium
Aluminum
Americium
Antimony
Argon
Arsenic
Astatine
Barium
Berkelium
Beryllium
Bismuth
Boron
Bromine
Cadmium
Calcium
Californium
Carbon
Cerium
Cesium
Chlorine
Chromium
Cobalt
Copper
Curium
Dysprosium
Einsteinium
Erbium
Europium
Fermium
Fluorine
Francium
Gadolinium
Gallium
Germanium
Gold
Hafnium
Helium
Holmium
Hydrogen
Indium
Iodine
Iridium
Iron
Krypton
Lanthanium
Lawrencium
Lead
Lithium
Lutetium
Magnesium
Manganese
Mendelevium
Symbol
Ac
Al
Am
Sb
Ar
As
At
Ba
Bk
Be
Bi
B
Br
Cd
Ca
Cf
C
Ce
Cs
Cl
Cr
Co
Cu
Cm
oy
Es
Er
Eu
Fm
F
Fr
Gd
Ga
Ge
Au
Hf
He
Ho
H
In
I
Ir
Fe
Kr
La
Lr
Pb
Li
Lu
Mg
Mn
Md
Atomic
Number
89
13
95
51
18
33
85
56
97
4
83
5
35
48
20
98
6
58
55
17
24
27
29
96
66
99
68
63
100
9
87
64
31
32
79
72
2
67
1
49
53
77
26
36
57
103
82
3
71
12
25
101
Chemical
Element
Mercury
Molybdenum
Neodymium
Neon
Neptunium
Nickel
Niobium
Nitrogen
Nobelium
Osmium
Oxygen
Palladium
Phosphorus
Platinum
Plutonium
Polonium
Potassium
Praseodymium
Promethium
Protactinium
Radium
Radon
Rhenium
Rhodium
Rubidium
Rutheium
Samarium
Scandium
Selenium
Silicon
Silver
Sodium
Strontium
Sulfur
Tantalum
Technetium
Tellurium
Terbium
Thallium
Thorium
Thulium
Tin
Titanium
Tungsten
Uranium
Vanadium
Xenon
Ytterbium
Yttrium
Zinc
Zirconium
Symbol
Hg
Mo
Nd
Ne
Np
Ni
Nb
N
No
Os
0
Pd
P
Pt
Pu
Po
K
Pr
Pm
Pa
Ra
Rn
Re
Rh
Rb
Ru
Sm
Sc
Se
Si
Ag
Na
Sr
S
Ta
Tc
Te
Tb
Tl
Th
Tm
Sn
Ti
W
U
V
Xe
Yb
Y
Zn
Zr
Atomic
Number
80
42
60
10
93
28
41
7
102
76
8
46
15
78
94
84
19
59
61
91
88
86
75
45
37
44
62
21
34
14
47
11
38
16
73
43
52
65
81
90
69
50
22
74
92
23
54
70
39
30
40
-------
APPENDIX B
AVERAGE ANNUAL CONCENTRATIONS
YIELDING 4 MILLIREM PER YEAR
-------
Annual Average Concentrations Yielding 4 Millirem per Year for a Two
Liter Daily Intake, From National Interim Primary Drinking Water Regula
tions, EPA-570/9-76-003
Half-Life Greater than 24 Hours
Radionuclide
Tritium
I*
6^
n-
>
15P
16S
?7C1
20C*
20C*
aSc
21S<
241SC
48v
23
i/.^r
Critical Organ
Total Body
GI (LLI)
Fat
Total Body
GI (S)
Bone
Testis
Total Body
Bone
Bone
GI(LLi)
GI(LLI)
GI(LLI)
GI(LLI)
GI(LLI)
C4
(pCi/1)
20,000
6,000
2,000
400
600
30
500
700
10
80
1,000
300
80
90
6,000
-------
Radionuclide
>
>
11"
l>
>
27°°
62°Co
>
28N1
SO2"
>
73,
33AS
33AS
76.
33AS
>
75Se
Critical Organ
GI(LLI)
Gl(LLI)
Spleen
Gl(LLl)
GI(LLI)
GI(LLI)
GI(LLI)
Bone
Bone
Liver
GI(LLI)
GI(LLI)
GI(LLI)
GI(LLI)
GI(LLI)
Kidney
C4
(pCi/1)
90
300
2,200
200
1,000
300
100
300
50
300
6,000
1,000
100
60
200
900
-------
Radionu elide
35Br
37RD
3>
38Sr
>
38Sr
90C
38Sr
90
39
91Y
39
40Zr
40Zr
4>
>
42M°
9463-
97mTc
Critical Organ
GI(LLI)
Total Body
Pancreas
GI(SI)
Bone
Bone Marrow (FRC)
Bone Marrow (FRC)
GI(LLI)
GI(LLI)
GI(LLI)
GI(LLI)
GI(LLI)
GI(LLI)
Kidney
GI(LLI)
GI(LLI)
C4
(pCi/1)
100
600
300
21,000
20
80
8
60
90
2,000
200
1,000
300
600
300
1,000
-------
Radionuclide
97TV
43TC
99
43
97p
. ,Ru
44
103D
. . Ru
44
106,,
/ / Ru
44
4>
}>
109
/ e. ^d
46
105.
47 AS
110m.
47 Ag
111.
47 A8
109
48 Cd
i85mCd
48
115PH
48 Cd
115T
49 In
Il3qn
<;n Sn
Critical Organ
GI(LH)
GI(LH)
GI(LLI)
GI(LLI)
GI(LLI)
GI(LLI)
GI(LLl)
GI(LH)
GI(LLI)
GI(LLI)
GI(LLI)
GI(LLI)
GI(LLI)
GI(LLI)
GI(LLI)
GI(LLI)
C4
(pCi/1)
6,000
900
1,000
200
30
300
900
300
300
90
100
600
90
90
300
300
-------
Radionu elide
125.
50 Sn
122
«2Sb
51 Sb
51 Sb
125mTe
52 ie
127mr0
52 e
52 Te
129mTe
52
529le
52lmTe
132Te
52 ie
125
53
126
53 L
129
53
131
53
131r
55 CS
Critical Organ
GI(LLI)
GI(LLI)
GI(LLI)
GI(LLI)
Kidney
Kidney
GI(LLI)
GI(LLI)
GI(S)
GI(LLI)
GI(LLI)
Thyroid
Thyroid
Thyroid
Thyroid
Total Body
C4
(pCi/1)
60
90
60
300
600
200
900
90
2,000
200
90
3
3
1
3
20,000
-------
Radionuclide
55 Cs
135
55 CS
5fCs
137
55 LS
5fBa
56°Ba
14 0T
57 La
58 Ce
143r
58 Ce
143Pr
58
149
61 m
62lsm
S3"
>
63 U
153
64
Critical Organ
Total Body
Total Body
Total Body
Total Body
GI(LLI)
GI(LLI)
GI(LLI)
GI(LLI)
GI(LLI)
GI(LLI)
GI(LLI)
GI(LLI)
GI(LLI)
GI(LLI)
GI(LLI)
GI(LLI)
C4
(pCi/1)
80
900
800
200
600
90
60
300
100
100
100
1,000
200
60
200
600
-------
Radionuclide
16V
65 Tb
166,,
66^
166
67 H°
169
68 Er
170Tm
68 Tm
170_
69 Tm
171Tn,
69 Tm
175
70
17 7T
71 LU
72lRf
f/Ta
74
745W
753*e
756Re
Re
Critical Organ
GI(LLI)
GI(LLI)
GI(LLI)
GI(LLI)
GI(LLI)
GI(LLI)
GI(LLI)
GI(LLI)
GI(LLI)
GI(LLI)
GI(LLI)
GI(LLI)
GI(LLI)
GI(LLI)
GI(LLI)
GI(LLI)
C4
(pCl/1)
600
100
100
90
300
100
1,000
300
300
200
100
1,000
300
2,000
300
9,000
-------
Radionuclide
!85n
76 °S
191A
76 °S
193-
76 °s
190 r
77
92T
77Ir
19lPt
78
T^
7983-
I9?pt
78 r
196.
79 Au
198,
79 Au
19 7U
80 Hg
>
r-
i?»
206Bi
00 B1
Critical Organ
GI(LLI)
GI(LLI)
GI(LLI)
GI(LLI)
GI(LLI)
GI(LLI)
GI(LLI)
Kidney
GI(LLI)
GI(LLI)
GI(LLI)
Kidney
Kidney
GI(LLI)
GI(LLI)
GI(LLI)
C4
(pCi/1)
200
600
200
600
100
300
3,000
3,000
300
600
100
900
60
300
1,000
100
-------
C4
Radionuclide _ Critical Organ _ (pCi/1)
o GI(LLI) 200
O J
233
Pa GI(LLI) 300
-------
Half-Life Less than 24 Hours
C4
Radionuelide Critical Organ (pCi/1)
*8F GI(SI) 2,000
GI(S) 3,000
GI(S) 1,000
GI(S) 900
2?111
i^0
285"1
29Cu
3>
30Zn
3>
38mSr
38Sr
38Sr
91HU
39
92
39
Gl(LLI)
GI(LLI)
GI(LLI)
GI(LLI)
GI(LLI)
GI(S)
GI(LLI)
Total Body
GI(LLI)
GI(ULI)
GI(SI)
GI(ULI)
300
9,000
300
900
200
6,000
100
900
200
200
9,000
200
-------
Radionu elide
93Y
39
?fr
40
>
JS>
"*rc
43 1C
i>
44
£*•»•
113m_
49 In
114mT
49 In
115m_
49 In
53 Z
133
53
134I
53
sf1
"s^8
142Pr
Critical Organ
GI(LLI)
GI(LLI)
GI(ULI)
GI(LLI)
GI(ULI)
GI(ULI)
GI(S)
GI(ULI)
GI(LLI)
GI(ULI)
Thyroid
Thyro id
Thyroid
Thyroid
GI(S)
GI(LLI)
C4
(pCi/1)
90
60
3,000
30,000
20,000
300
30,000
3,000
60
1,000
90
10
100
30
20,000
90
-------
Radionuclide
609Nd
6fEu
159r,
64 w
16 5_
66 ^
171.,
68 Er
18 7w
74
?>
r*
194T
77 Ir
197m
78 r
202
ai A
Critical Organ
GI(LLI)
GI(LLI)
GI(LLI)
GI(LLI)
GI(ULI)
GI(LLI)
GI(LLI)
GI(LLI)
GI(LLI)
GI(ULI)
GI(LLI)
C4
(pCi/1)
900
200
200
1,000
300
200
200
9,000
90
3,000
300
-------
APPENDIX C
SAMPLING AND ANALYTICAL METHODS
FOR RADIOACTIVITY
-------
SAMPLING AND ANALYTICAL METHODS FOR
RADIOACTIVITY SPECIFIED IN NIPDWR
(a) The methods specified in Interim Radiochemical Monitoring for
Drinking Water, Environmental Monitoring and Support Laboratory,
EPA-600/4-75-008, U.S. EPA, Cincinnati, Ohio 45268, or those listed
below, are to be used to determine compliance with §§141.15
and 141.16 (radioactivity) except in cases where alternative methods
have been approved in accordance with §141.27.
(1) Gross Alpha and Beta—Method 302 "Gross Alpha and Beta Radio-
activity in Water", Standard Methods for the Examination of
Water and Wastewater, 13th Edition, American Public Health
Association, New York, New York, 1971.
(2) Total Radium—Method 304 "Radium in Water by Precipitation,"
Ibid.
(3) Radium-226—Method 305 "Radium-226 by Radon in Water," Ibid.
(4) Strontium-89, 90—Method 303 "Total Strontium and Strontium-90
in Water," Ibid.
(5) Tritium—Method 306 "Tritium in Water," Ibid.
(6) Cesium-134—ASTM D-2459 "Gamma Spectrometry in Water,"
1975 Annual Book of ASTM Standards, Water and Atmospheric
Analysis, Part 31, American Society for Testing and Materials,
Philadelphia, Pennsylvania (1975).
(7) Uranium—ASTM D-2907 "Microquantities of Uranium in Water by
Fluorometry," Ibid.
(b) When the identification and measurement of radionuclides other than
those listed in paragraph (a) are required, the following references
are to be used, except in cases where alternative methods have
been approved in accordance with §141.27.
(1) Procedures for Radiochemical Analysis of Nuclear Reactor
Aqueous Solutions, H.L. Krieger and S. Gold, EPA-R4-73-014.
U.S. EPA, Cincinnati, Ohio, May 1973.
(2) HASL Procedure Manual, Edited by John H. Harley. HASL 300,
ERDA Health and Safety Laboratory, New York, New York, 1973.
-------
APPENDIX D
DISCUSSION OF RADIOACTIVE UNITS
-------
DISCUSSION OF UNITS OF RADIOACTIVITY
The effect of radioactivity depends not only on the number of radiations
emitted per second, but on the kind of radiations (alpha, beta, or
gamma) and their energies. These properties are expressed in
terms of the dose or "punch" given to tissue or matter.
As discussed in Section II, two units are used to define radioactive
dosage. One unit of dose is called a rad (radiation absorbed); one rad
is defined as the dose that deposits 100 ergs (a metric unit of energy)
in one gram of matter (such as human tissue). Ten million ergs per
second is one watt. In general, these units are quite large and engi-
neering shorthand is used to simplify working with them. The following
table gives the meaning of some useful and commonly used prefixes. As
indicated in the Table D-l, a millimeter is one one-thousandth (1/1000) of a
meter and a kilogram is a thousand grams. Similarly 1 picocurie (pCi) is
one million millionth of a curie and is abbreviated 1 pCi. Also,
1 millirad (1 rad) is one one-thousandth of a rad. These latter units
are common levels of activity and absorbed radiation found relating to
drinking water. (The Roentgen [R] is a similar unit used in describing
x-ray and gamma ray exposure. The basic differences between the R and
the rad centers around a unit of exposure versus a unit of energy
absorption.)
TABLE D-l
ENGINEERING SHORTHAND AND GREEK PREFIXES
Greek Prefix
mega
kilo
centi
milli
Abbreviation
M
k
m
Value
1,000,000
1,000
10
1
1,000
Engineering
Shorthand
106
io3
10
_3
10 one part per
thousand
micro
nano
pico
femto
u
n
P
f
1,000,000
1
1,000,000,000
1/1,000,000,000,000
1/1,000,000,000,000,000
10 one part per
million (ppm)
_9
10 one part per
billion (ppb)
-12
10
10
,-15
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DISCUSSION OF UNITS OF RADIOACTIVITY
(Continued)
Because of the particle mass and charge, 1 rad of alpha particles creates
more biological damage than 1 rad of gamma rays. To compensate for this
difference in effect a new unit was invented — the rem, radiation
equivalent man. This unit is called the dose equivalent. The dose is
measured in rads and the dose equivalent is measured in rem. Frequently,
the rem is called the dose. The dose equivalent is a measure of harm
and is not generally an exact measurement; it is a useful unit for
regulations. The rad and rem are related as follows:
number of rems (dose (Q times the number of rads (dose)
equivalent to man)
where Q is the measure of relative ability to cause biological damage in
man, Q has been assigned the following values:
Q = 1 for beta particles and all electromagnetic radiations
(gamma ray and x-rays)
= 10 for neutrons from spontaneous fission and protons
= 20 for alpha particles (The quality factor for alpha particles
was taken to be 10 at the time regulations were promulgated
for radioactivity in drinking water.)
The average human in the United States receives about 100 mrem/yr from
cosmic rays (high energy protons from outside the earth) and natural
background radiation. This can vary depending on where one lives and
the kind of a structure in which one lives and works. The higher the
altitude, the less protection afforded from the earth's atmosphere.
Thus, people in Leadville, Colorado, receive 110 mrem/yr from cosmic
rays, while people at sea level (i.e., Washington, DC) receive about
20 mrem/yr. Flying coast-to-coast can add as much as 5 mrem per flight.
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