GUIDANCE MANUAL
                                  FOR
                          COMPLIANCE WITH  THE
                FILTRATION AND DISINFECTION REQUIREMENTS
                                  FOR
                         PUBLIC HATER SYSTEMS
                                 USING
                         SURFACE WATER SOURCES
                                  for
                      Science and Technlogy Branch
                    Criteria and Standards Division
                       Office of Drinking Water
                  U.S.  Environmental Protection Agency
                           Washington, D.C.
                        Contract No. 63-01-6989
                                   by
Mil coin Plmie, Inc.                      CHC-HDR,  Inc.
100 Eisenhower Drive                      3461 Robin Lane
Paraous, New Jersey 07R53                 Cameron Park, California 95682
                         October,  1989  Edition

-------
TABLE OF CONTENTS
1. INTRODUCTION 1 -1
2. GENERAL REQUIREMENTS 2-1
2.1 Application 2- 1
2.1.1 Types of Water Supplies 2-2
2.1.2 Determination of Applicable Sources 2 -3
2.2 Treatment Requirements 2- 13
2.3 Operator Personnel Qualifications 2-14
3. COMPLIANCE FOR SYSTEMS NOT FILTERING 3- 1
3.1 Source Water Quality Criteria 3-1
3.1.1 Coliform Concentrations 3-2
3.1.2 Turbidity Levels 3—4
3.2 Disinfection Criteria 3-6
3.2.1 Inactivation Requirements 3-6
3.2.2 Determination of Overall Inactivation
for Residual Profile, Multiple
Disinfectants and Multiple Sources
and Multiple Sources 3-19
3.2.3 Demonstration of Maintaining a Residual 3-29
3.2.4 Disinfection System Redundancy 3-32
3.2 Site-Specific Conditions 3-34
3.3.1 Watershed Control Program 3-35
3.3.2 On-site inspection 3-37
3.3.3 No DFsease Outbreaks 3-40
3 .3.4 Monthly Coliforn MCI 3—41
3.3.STotal Trihalomethane (TTHM) Regulations 3-42
4. DESIGN AND OPERAT ING CRITERIA FOR F iLTRATION AND
DISINFECTION TECHNOLOGY 4-1
4.1 Introduction 4— 1
4.2 Selection of Appropriate Filtration Technology 4-1
4.2.1 General Descriptions 4-2
4.2.2 Capabilities 4-3
4.2.3 Selection 44
4.3 Available Filtration Technologies 4-9
4.3.1 Introduction 4-9
4.3.2 General 4-10
4.3.3 Conventional Treatment 4-13
4.3.4 Direct Filtration 4-17
4.3.5 Slow Sand Filtration 4-18
4.3.6 Olatomaceous Earth Filtration 4-21
4.3.1 Alternate Technologies 4-22
4.3.8 Nontreatment Alternatives 4-24
4.4 DIsinfection 4-25
4.4.1 General 4—25
4.4.2 Recomended Removal/InactivatiOn 4-25
4.4.3 Total Trihalomethane (Tilifi) Regulations 4-29

-------
TABLE OF CONTENTS (Continued )
5. CRITERIA FOR DETERMINING IF FILTRATION AND DISINFECTION
ARE SATISFACTORILY PRACTICED 5-1
5.1- Introduction 5-1
5.2 Turbidity Monitoring Requirements 5-1
5.2.1 Sampling Location 5-1
5.2.2 Sampling Frequency 5-2
5.2.3 Additional Monitoring 5-3
5.3 Turbidity Performance Criteria 5-3
5.3.1 Conventional Treatment or
Direct Filtration 5.5
5.3.2 Slow Sand Filtration 5.7
5.3.3 Diatomaceous Earth FiltratIon 5-7
5.3.4 Other Filtration Technologies 5-8
5.4 Disinfection Monitoring Requirements 5-B
5.5 Disinfection Performance Criteria 5—9
5.5.1 Minimum Performance Criteria Required
Under the SWTR 5..9
5.5.2 Recomended Performance Criteria 5-10
5.5.3 Disinfection By-Product Considerations 5—12
5.5.4 Determination of Inactivation by
Disinfection 5-14
5.6 Other Considerations 5-29
6. REPORTING 6-1
5.1 Reporting Requirements for Public Water Systems
Not Providing Filtration 6-1
6.2 Reporting Requirements for Public Water Systems
Using Filtration 6—3
7. COMPLIANCE 7- i
7.1 IntroductIon 7—1
7.2 Systems Using a Surface Water Source
(Not Ground Water Under the Direct
Influence of Surface Water) 7-1
7.3 Co lIance Transition with Current NPOWR
Turbidity Requirements 7-3
74 Syst Using a Ground Water Source Under
the Direct Influence of a Surface Water 7—4
7.5 Responses for Systems not Meeting the SWTR Criteria 7-6
7.5.1 Introduction 7-6
7.5.2 Systems Not Filtering 7-6
7.5.3 Systems Currently Filtering 74
8. PUBLIC NOTIFICATION 8-1

-------
TABLE OF CONTENTS (Continued )
9. EXEMPTIONS 9-1
9.1 Overview of Requirements
9.2 Recoariended Criteria 9-2
9.3 Compelling Factors 9-3
9.4 Evaluation of Alternate Water Supply Sources 9- 7
9.5 Protection of Public Health 9-7
9.5 Notification to EPA 9 —11
L IST OF TABLES
Table Following
No. DescriDtion Pa ge
2- I Survey Form for the Classification of Drinking
Water Sources
4-I Removal Capabilities of Filtration Processes 4—3
4-2 Generalized Capability of Filtration Systems to
Accounodate Raw Water Quality Conditions 4-8
6-1 Source Water Quality Conditions for Unfiltered
Systems 6-4
6-2 Lon 9 Term Source Water Quality Conditions for
Unfiltered Systems 6-4
6-3 CT Determination for Unfiltered Systems -
Monthly Report to Primacy Agency 6-4
6-4 DisInfection Information for Unfiltered Systems -
Montly Report to Primacy Agency 6-4
6-5 Distribution System Disinfectant Residual Data for
Unfiltered and Filters Systems • Monthly Report to
Primacy Agency 6-4
6-6 Monthly Report to Primacy Agency for Compliance
Oetersination — Unfiltered Systems 6-4
6-7 Daily Data Sheet for Filtered Systems 6-4
6-8 Monthly Report to Primacy Agency for Compliance
Deterimination-Filtered Systems 6-4
7-1 Requirements for Unfiltered Systems 1-3
7-2 Requirements før Filtered Systems 7-3

-------
TABLE OF CONTENTS (Cont nued
LIST OF FIGURES
Figure Following
Np. Description Pace
2—1 Steps to Source Classification 2-4
3-1 Single Chamber Contactor
3-2 Multiple Chamber Contactor
3-3 Turbine Contactor
3—4 CIty of Tuscan Ozone Contactor
3-5 Average Ozone Residuals Los Angeles Aqueduct
Filtration Plant
3-6 DeterminatIon of Inactivation for Multiple
Disinfectant Application to a Surface Water
Source 3-22
3-7 Individually Disinfected Surface Sources Combined
at a Single Point 3-25
3-8 Multiple Combination Points for Individually
Disinfected Surface Sources 3-25
4-i Flow Sheet for a Typical Conventional Water
Treatment Plant 4-13
4-2 Flow Sheet for Typical Softening Treatment Plants 4-14
4-3 Flow Sheet for a Typical Direct Filtration Plant 4-17
4—4 flow Sheet for a Typical Direct Filtration Plant 4-i l
with Flocculation
LIST OF APPENDICES
ADDendix Description
A Use of Particulate Analysis for Source and Water
Treatment Evaluation A-i
B Institutional Control of Leglonella B-i
C Determination Of Disinfectant Contact Time C-i

-------
TABLE OF CONTENTS LContinued)
LIST OF APPENDICES
Aopertdlx Description
D Analytical Requirements of the SWTR and a Survey
of the Current Status of Residual Disinfectant
Measurement Methods for all Chlorine Species and Ozone D-1
( Inactivation Achieved by Various Disinfectants E-1
F Basis for CT Values F-I
G Protocol for Demonstrating Effective Disinfection G-1
H Sampling Frequency for Total Coliforms in the
Distribution System H—i
1 Maintaining Redundant Disinfection Capability I-i
J Watershed Control Program
K Sanitary Survey K-I
L Small System Considerations L—l
H Protocol for Demonstration of effective Treatment H-i
N Protocols for Point-of-Use Treatment Deyices N-i

-------
1. INTRODUCTION
This Guidance Manual complements the filtration and dis nfectio
treatment requirements for public water systems using surface water
sources or ground water under the direct influence of surface water
promulgated in 40 CFR Part 141, Subpart H. In this manual, these
requirements are referred to as in the Surface Water Treatment Rule
(SWTR).
The purpose of this manual is to provide guidance to United States
Environmental Protection Agency (USEPA) Regional Offices, Primacy Agencies
and affected utilities in the implementation of the SWIR, and to help
assure that implementation is consistent. For example, the SWTR sets
treatment requirements which apply to a large range of source water
conditions. The guidance manual suggests design, operating and perform-
ance criteria for specific surface water quality conditions to provide the
optimum protection from microbiological contaminants. These recomenda-
tions are presented as advisory guidelines only; unlike the provisions of
the SWIR, these recomendations are not mandatory requirements. In many
cases, it will be appropriate to tailor requirements to specific
circumstances; the guidance manual Is designed to give the Primacy Agency
flexibility in establishing the most appropriate treatment requirements
for the systems within their jurisdiction.
Throughout this document, the term “Primacy Agency” refers to a
State with primary enforcement responsibility for public water systems or
“primacy,” or to mean EPA in the case of a State that has not obtained
primacy.
In order to facilitate the use of this manual, it has been
structured to follow the framework of the SWIR as closely as possible.
Brief descriptions of the contents of each section of this manual are
presented In the following paragraphs.
SectIon 2
This section provides guidance for determining whether a water
supply source Is subject to the requirements of the SWIR including the
I—’

-------
determination of whether a ground water source is under the direct
influence of surface water i.e. at risk for the presence of Giardia cysts
or other large microorganisms. The overall treatment requirements of the
SWTR are also presented, along with recorm endations for the qualifications
of operator personnel.
Section 3
For systems which are subject to the requirements of the SWTR and
which do not currently provide filtration, this section provides guidance
to the Primacy Agency for determining if a given system:
— Meets the source water quality criteria
- Meets the disinfection requirements including:
- 99.9 and gg•gg percent inactivation of Glardia cysts and
viruses and application of the CT (disinfectant residual
concentration x contact time) concept
— Point of entry to distribution system requirements
— Distribution system requirements
- Provision for disinfection system redundancy
- Maintains an adequate watershed control program
- Meets the on-site inspection requirements
- Has not had an identified waterborne disease outbreak
- Complies with the requirements of the revised Total Coliform
Rule
- Complies with Total Trihalomethane (TTHM) Rule
Section 4
This section pertains to systems which do not meet the requirements
to avoid filtration outlined In SectIon 3 and therefore are required to
install filtration. Guidance is given for the selection of an appropnate.
filtratlon technologybased on the source water quality and the capabili-
ties of various technologies to achieve the required performance criteria.
1-2

-------
in addition 1 reconrended design and operating criteria are provided for
different filtration techno]oqies.
Sec i l orL i
Section 5 presents guidance to the Primacy Agency for determining
compliance wtth the turbidity and disinfection performance resuirer ents,
and in turn, whether filtration and disinfection are satisfactorily
practiced. Reconenendations are made for the level of disinfection to be
provided in order to meet the overall treatment requirements of the SW1R.
This section describes how to evaluate the adequacy of disinfection using
CT or other methods.
Sect i onA
section 6 provides guidelines to the Primacy Agency for establishing
the reporting requirements associated with the SWIR. The requirements
include report content and frequency 1 and are applicable to both filtering
and nonfiltering systems.
Sect io n
This section provides an overview of the schedule for Primacy
Agencies and utilities to meet the requirements of the SWIlL Examples are
presented to provide guidance for corrective measures which can be taken
by systems which are not in compliance with the treatment requirements.
Secti onI
This section presents guidance on public notification. Included are
examples of events which would require notification, language for the
notices and the methods of notification.
Sect IonS
Sect Ion 9 provides guidance to the Primacy Agency for determining
whether a system is eligible for an exeption. The criteria for
eligibility for an exemption include:
— Compelling factors (economic or resource limitations)
- No available alternate source
1-3

-------
Protection of public health
This section also provides guidance for evaluating the financial
capabilities of a water system, reviewing the avaflability of alternate
sources and suggests interim measures for protecting public health.
Aoøend ices
The manual also contains appendices which provide more detailed
guidance in specific areas. These Include:
Appendix A — EPA Consensus
Method for Giardia cyst Analysis
Several procedures are available for Giardia cyst analysis in water.
In 1983 the USEPA held a conference to establish a consensus on the
procedure to be used in the future. This consensus method would promote
uniformity in testing and provide a basis for future conparisons. The
consensus method and the background data used to develop in it presented
in this appendix.
Appendix B - Institutional
Control of Legionella
Filtration and/or disinfection provides protection from L.egionella .
However, it does not assure that recontamination or regrowth will not
occur in the hot water or cooling systems of buildings within the
distribution system. This appendix provides guidance for monitoring and
treatment which can be used by Institutional systems for the control of
legionel la.
Aomendlx C - Determination of Olsthfectant
Contact Time
In aany cases, the determination of disinfectant contact times
needed to evaluate the CT of a water system will necessitate the use of
tracer studies. This appendix provides guidance for conducting these
studies. In so ::se: It may not be practical to conduct a tracer study.
1-4

-------
For such cases guidance is given for estimating the detention time based
on the phys cal configuration of the system.
Appendix 0 - Analytical Requirements
of the SWTR and A Survey of the Current
Status of Residual Disinfectant
Measurement Methods for all Chlorine
Species and Ozone
This appendix includes a listing of the analytical methods required
under the SWIR. An executive sui inary of a report on the analytical
methods used to measure the residual concentrations of the various
disinfectants is included. The reliability and limitations of each of the
methods are presented.
Appendix E - Inactivations Achieved
by the Various Olsinfectants
This appendix presents the log inactivations of Gtardia cysts and
viruses which are achieved at various CT levels by chlorine, chlorine
dioxide, chioramines and ozone. Inactivations of viruses achieved by UV
absorbance are also included.
Acoendix F - Basis for CT Values
This appendix provides the background and rationale utilized in
developing the CT values for the various disinfectants. Included is a
paper by Clark et aL, 1988, in which a mathematical model was used in the
determination of CT values for free chlorine.
Appendix G — Protocol for Demonstrating
Effective Disinfection
This appendix provides the recomended protocols for demonstrating
the effectiveness of chloramines, chlorine dioxide and ozone as primary
disinfectants. Guidelines for determing characteristic C’ and NTU .f
ozone reactors are also included.
1-5

-------
Appendix H - Sampling Frequency for
Total Coliforms in the Oistribut on System
The sampling frequency required by the revised Total Coliform Rule
54 FR 27544 (June 29, 1989) is presented in this appendix.
Appendix 1 - Maintaining
Redundant Disinfection Caoability
This appendix details the conditions and equipment which should be
maintained by a system using chlorine, chlorine dioxide, ozone or
chioramines to assure that compliance with the SWTR requirement for
redundant disinfection is met.
Anoendix J - Watershed Control Program
This appendix provides a detailed outline of a watershed program.
This program may be adjusted by the Primacy Agency to serve the specific
needs of a particular water system.
Appendix K - Sanitary Survey
This appendix provides guidance for conducting a conprehersive
sanitary survey of a supply source and its treatment and delivery to the
consumer. Suggested elements of an annual on-site inspection are included
in Section 3.
A pendix I - Small System Considerations
This appendix describes difficulties which way be faced by smafl
systems in complying with the SWTR along with guidelines for overcoming
these difficulties.
Appendix N — Protocol for the
Oemonstrattan of ffectlve Treatment
This appendix presents pilot study protocols to evaluate the
effectiveness of an alternate filtration technology In meeting the
performance requirements of the SWIR. it presents the use of particle
size analysis for demonstrating tne actual r val-of QJ rdfa cyst
achieved by a treatment train. Guidance for conventional and direct
1-6

-------
filtration plants to demonstrate that adequate filtration is being
maintained at effluent turbidities between 0.5 and 1 Nephelometric
Turbidity Unit (NTU) is also included.
Appendix N - Protocol for
Point-of-Use Treatment Devices
In some limited cases, it may be appropriate to install point-of-use
(P0 1 . 1) or point-of-entry (POE) treatment devices as an interim measure to
prodde protection to the public health. This appendix provides a
protocol for evaluating and determining the efficacy of POU/POE treatment
devices.
1-7

-------
2. GENERAL REOUIREMENTS
2.1 Aoo]jcatjon
The SWTR pertains to all public water systems which utilize a surface
water source or ground water source under the direct influence of surface
water. The SWTR defines a surface water as all waters which are open to
the atmosphere and subject to surface runoff. Ground water under the
direct influence of surface water is defined as: any water beneath the
surface of the ground with (i) significant occurrence of insects or other
macroorganisms, algae, organic debris, or large—diameter pathogens such
as Giardip lamblia, or (ii) significant and relatively rapid shifts in
water characteristics such as turbidity, temperature, conductivity, or pH
which closely correlate to climatological or surface water conditions.
Direct influence must be determined for each individual source in
accordance with criteria established by the Primacy Agency. The Primacy
Agency criteria nay provide for documentation of well construction and
geology, with field evaluation, or site-specific measdreme l lts of water
quality as explained in Section 2.1.2.
Saline water sources such as the ocean are not generally considered
to be subject to the requirements of the SWIR because of the low survival
time of pathogens in a saline environment (Ge ldreich, 1989). Pathogens
generally can only survive a few hours in saline water and any remaining
pathogens should be removed or inactivated during desalination. However,
it is up to the Primacy Agency’s discretion to determine which systems
must meet the SWTR requirements. In cases where there is a sewage
discharge located near the water intake, it may be appropriate for the
Primacy Agency to require the system to comply with the SWIR.
The traditional concept that all water In subsurface aquifers is free
from pathogenic organisms is based upon soil being an effective filter
that removes microorganisms and other relatively large particles by
straining and antagonistic effects (Bouwer, 1978). In most cases
pathogenic bacteria retained in the soil find themselves ina hostile
environment, are not able to multiply and eventually die. l 1 ver, some
underground sources of drinking water may be subject to contamination by
pathogenic organisms from the direct influence of nearby surface
waters.
2- 1

-------
Only those subsurface sources which are at risk to contamination from
Giardia cysts will be subject to the requirements of the SWTR. Giardia
cysts generally range in size from 7 to 12 urn. S osurface sources which
may be at risk to contamination from bacteria and enteric viruses, but
which are not at risk from Gi rdia cysts will be regulated either under
the Total Caliform Rule or forthcoming disinfection treatment requirements
for ground waters. EPA intends to promulgate disinfection requirements
for ground water systems in conjunction with regulations for disinfection
by-products by 1992.
2.1.1 Tvoes of Water Supolies
Si rf ace Waters
Surface water supplies that are often used as sources of drinking
water include two m&jor classifications, running and quiescent waters.
Streams, rivers and brooks are examples of running water, while lakes,
reservoirs, impoundments and ponds are examples of quiescent waters. The
exposure of surface waters to the atmosphere results in exposure to
precipitation events, surface water runoff and contamin!ticn th rticro
and macroorganisms resulting from activities in their surrounding areas.
These sources are subject to the requirements of the SWTR.
Systems with rain water catchments not subject to surface runoff
(e.g. roof catchoent areas) are not considered vulnerable to contamination
from animal populations which carry protozoan cysts pathogenic to humans
and are thus not subject to the SWTR requirements. However, such systems
should at least provide disinfection to treat for potential bacterial and
viral contamination coming from bird populatlons.
Ground Waters under Direct Influence of Surface Water
Ground water sources which may be subject to contamination with
pathogenic organisms from surface waters include, springs, infiltration
galleries, wells or other collectors in subsurface aquifers. The
following section presents a reco ended procedure for determining whether
a source will be subject to the requirements of the SWTR. These
determinations are to be made for each Individual source. If the.
One study (l4arkwell and Shortrldge 1981) Indicates that a
cycle of waterborne transmission and maintenance of Influenza
virus may exist within duck c unlt1es, and that It IS
conceivable for virus transmission to occur In this manner to
other susceptible animals, Including humans.
2-2

-------
determination will involve an evaluation of water quality, eg. parttculate
analysis, it is important that these analyses be made on water taken
directly from the source and not on blended water or water from the
distribution system.
2.1.2 Determination of A p1jcable Sources
The Primacy Agency has the responsibility for determining which water
supplies must meet the requirements of the SWTR. However, it is the
responsibility of the water purveyors to provide the Primacy Agency with
the information needed to make this determination. This section provides
guidance to the Primacy Agency for determining which water supplies are
surface waters or ground waters directly influenced by a surface water and
are thereby subject to the requirements of the SWTR. Following the
determination that the source is subject to the SWTR, the requirements
enumerated in Sections 2.2 and 2.3 must be met.
The Primacy Agency must develop a program for evaluating ground water
sources for direct influence by Oecember 30, 1990. All coulnunity ground
water systems mu t be evaluated by June 29, 1994, while all non-cormunity
systems must be evaluated by June 29, 1999. Primacy Agencies with an
approved Welihead Protection (WHP) Program, may be able to use the WHP
program’s requirements which include delineation of welihead protection
areas, assessment of sources of contamination and implementation of
management control measures. These same requirements can be used for
meeting the requirements of the watershed control program for ground water
under the direct influence of a surface water.
A multiple step approach has been developed as the recommended method
of determining whether a ground water source is under direct influence of
a surface water. This approach includes the review of information
gathered during sanitary surveys. As defined by the USEPAS a sanitary
survey is an on—site review of the water source, facilities, equipment
operation and maintenance of a public water system for the purpose of
evaluating the adequacy of such source, facilities, equipment, operation
and maintenance for producing and distributing safe drinking water.
Sanitary surveys are required under the Total Collfar, Rule and may be
required under the forthcoming disinfection requirements for ground water
systems as a condition for obtaining a variance or for deter ining the
level of disinfection required. Therefore, it is recoemended that the
2-3

-------
determination of direct influence be correlated with the sanitary surveys
conducted under these other requirements.
A. Source Evaluation Protocol
As illustrated on Figure 2-1, the determination of whether a source
is subject to the requirements of the SWTR may involve one or more of the
following steps:
1. A review of the records of the systems source(s) to determine
whether the source is obviously a surface water, i.e. pond,
lake, streams, etc.
2. If the source is a well, determination of whether it is clearly
a ground water source, or whether further analysis is needed
to deteninne possible direct surface water influence.
3. A complete review of the system ’s files followed by a field
sanitary survey. Pertinent information to gather in the file
review and field survey includes: source design and construc-
tion; evidence of direct surface water contamination; water
quality analysis; indications of waterborne disease outbreaks;
operational procedures; and customer complaints regarding water
quality or water related intectious illness.
4. Conducting particulate analyses and other water quality
sampling and analyses.
SteD 1. Records Peview
A review of information pertaining to each source should be carried
out to identify those sources which are obvious surface waters. These
would include ponds, lakes, streams, rivers, reservoirs, etc. If the
source is a surface water, then the SWTR would apply 1 and criteria in the
rule would need to be applied to determine If filtration Is necessary.
If the source is not an obvious surface water, then further analyses, as
presented in Steps 2, 3, or 4, are needed to determine if the SWIR will
apply. If the source is a well, go to Step 2. If the source is a spring,
infiltration gallery, Ranney well, or any other subsurface source, proceed
to Step 3 for a more detailed analysis.
Steo 2. Review of Well Sources
While most well sources have historically been considered to be all
ground water, recent evidence suggests that some wells, especially shallow
wells constructed near surface waters, may be directly lmfluenced by
2-4

-------
Summary of Findings
tndcate Source is
tnttuenceC by Surface
Water and Could
Contain Giai ta?
Cbvious SwTace
Sources
Lakes eservoirs
Streams Creeks
verS e c
Cor cuct Pani .ilate
Analysis. Monitor
Changes :r. Water
Quality, Terr erature.
etc.
FIGURE 2.t STEPS TO SOURCE CLASSIFICATION

-------
surface water. One approach in determining whether a well is subject to
contamination by surface water would be to evaluate the water quality of
the well by the criteria in Step 4. However, this process is rather tune
consuming and labor intensive. In an attempt to reduce the effort needed
to evaluate well sources, a set of criteria has been developed to identify
wells in deep, well protected aquifers which are not subject to contattuna-
tion from surface water. While these criteria are not as definitive as
water quality analysis, it is believed that they provide a reasonable
degree of accuracy, and allow for a relatively rapid determination for a
large number of well sources in the U.S.
Wells less than or equal to 50 feet in depth are considered to be
shallow wells 1 and should be evaluated for direct surface influence
according to steps 3 and/or 4. For wells greater than 50 feet in depth,
State or system files should be reviewed for the criteria listed below:
1. The well construction should include:
- A surface canit ry seal using bentonite clay, concrete
or other acceptable material.
— A well casing that penetrates a confining bed.
— A well casing that is only perforated or screened below
a confining bed.
2. The source should be located at least 200 feet from any surface
water.
3. The water quality records should indicate:
- No record of total coliform or fecal collform contamina-
tion in untreated samples collected over the past three
years.
- No history of turbidity problems associated with the
source.
- No history of known or suspected outbreak of Giardia 1 or
other pathogenic organism associated with surface water
(e.g. Crvotosooridlum) , which has been attributed to that
source.
4. If data is available for particulate matter In the well there
should be:
— No evidence of particulate matter associated with
surface water.
2-5

-------
If data is available for turbidity or temperature from the
well and a nearby surface water there should be:
- No turbidity or temperature data which correlates
to that of a nearby surface water.
Wells that meet all of the criteria listed above are not subject to
the requirements of the SWIR, and no additional evaluation is needed.
Wells that do not meet all the requirements listed require further
evaluation in accordance with Steps 3 and/or 4 to determine whether or not
they are directly influenced by surface water.
Steo 3. On—site Insoection
For sources other than a well source, the State or system files
should be reviewed for the source construction and water quality
conditions as listed in Step 2. Reviewing historical records in State or
system files is a valuable information gathering tool for any source.
However, the results may be inconclusive. ft sanitary survey in the field
ma be helpful in establishing a more definite determination of whether
the water source is at risk to pathogens from direct surface water
influence.
Information to obtain during an on-site inspection include:
- Evidence that surface water enters the source through defects
in the source such as lack of a surface seal on wells,
infiltration gallery laterals exposed to surface water, springs
open to the atmosphere, surface runoff entering a spring or
other collector, etc.
— Olstances to obvious surface water sources.
If the survey indicates that the well is subject to direct surface
water influence, the source must either be reconstructed as explained
later in this section or it must be treated in accordance with the
requir ents for the SW1R. If the survey does not show conclusive
2-6

-------
evidence of direct surface water influence, the analysis outlined in Step
4 should be conducted.
The Washington State Department of Social and Health Services has
developed a form to guide them and provide consistency in their evaluation
of sources for surface water influence (Notestine & Hudson, 1988). Table
2 -1 provides a copy of this form as a guide for evaluating sources.
Steo 4. Particulate Analysis and Other Indicators
a. Surface Water Indicators
Particulate analysis is intended to identify organisms which only
occur in surface waters as opposed to ground waters, and whose presence
in a ground water would clearly indicate that at least some surface water
has seen m xed with it. The EPA Consensus Method in Appendix A can be
used for Giardia cyst analysis.
In 1986 Hoffbuhr et. al. listed six parameters identifiable in a
particulate analysis which were believed to be valid indicators of surface
contamination of ground water. These were: diatoms, rotifers, coc ’ ,a,
plant debris, insect parts 1 and Giardia cysts. Later work by Notestine
and Hudson (1988) found that microbiologists did not afl define plant
debris in the same way, and that deep wells known to be free of direct
surface water influence were shown by particulate analysis to contain
‘plant debris” but none of the other five indicators. Their work suggests
that “plant debris” may not currently be a useful tool in determining
direct surface water influence, but may be in the future when a standard
definition of “plant debris” is developed. Therefore, it is recousnended
that only the presence of the other five parameters; diatoms and certain
other algae, rotifers, coccidia, insect parts, and Giardia , be used as
indicators of direct surface contamination. In addition, if other large
diameter (> 1 us) organisms which are clearly of surface water origin such
as O1 h11obothr4us are present, these should also be considered as
indicators of direct surface water Influence.
b. interpretation
Since standard methods have not been developed specifically for
particulate analysis, there has not been consistency In the way samples
have been collected and analyzed. Differences in the degree of training
and experience of the microbiologists has added further to the difficulty
2 -7

-------
TABLE 2-1
SURVEY FORM FOR THE CLASSIFICATION OF DRINKING WATER SOURCES
Genera l
1. Utility Name (ID#) __________________________________________________
2. Utility Person(s) Contacted ____________________________________________
3. Source Type (As shown on state inventory)
________ Spring ________ Ranney Well
________ Infiltration System ________ Shallow Well ________ Deep Well
4. Source Name __________________________________ Year constructed ________
5. Is this source used seasonally or intermittently? No _____ Yes
If yes, are water quality problems the reason? No _____ Yes_
6. Has there ever been a waterborne disease outbreak associated with this
source? Yes ______ No _______ If yes, explain _________________________
7. Have there been turbidity or bacteriological MCI violations within the last
five years associated with this source? No________ Yes __________
If yes, describe frequency, cause, remedial action (s) taken ___________
8. Have there been consumer complaints within the past five years associated
with this source? No ______ Yes _____ If yes, discuss nature, frequency,
remedial action taken_________________________________________
9. Is there any evidence of surface water intrusion (pH, temperature,
conductivity, etc. changes) during the year? Yes ______ No ______
If yes, describe _______________________________________________________
If no, submit supporting data.
10. Sketch of source in plan view (on an additional sheet)
-1—

-------
Shallow Wefls
1. Does the well meet good sanitary practices regarding location, con-
struction 1 seal etc. to prevent the entrance of surface water?
les ________ No ______ If no, describe the deficiencies _______________
3. Hydrogeology (Attach copy of well log or surmnarize it on reverse)
a. Depth to static water level? (Feet) ______________________________
b. Drawdown?(Feet) __________________________________________________
c. What is the depth to the highest screen or perforation? (Feet)
d. Are there impervious layers above the highest screen or perforation?
Yes ______ No _______ Unknown ______
Ifyes, please describe _________________________________________
4. Is there a permanent or intermittent surface water within 200 feet of the
well? Yes — No _____ If yes, describe (type, distance etc.) and
submit location map.
5.
What
is the elevation
elevation
elevation
of
of
of
normal
100 yr
bottom
pool
flood level
of labeor river
(ft
(ft
(ft
msl)
msl)
msl)
Additional coments:
2. What is the depth of the well?
E evation of top of casing?
Elevation of land surface?
_______ (ft)
_____ (ft msl)
______ (ft msl)
—2-

-------
Soring
1. a. What is the size of the catchnient area (acres)? ___________________
b. Give a general description of the area (terrain; vegetation; soil
etc.)
2. What is the vertical distance between the ground surface and the nearest
point of entry to the spring collector(s) (feet)? _______________________
3. How rapidly does rainfall percolate into the ground around the spring?
Percolates readily; seldom if ever any runoff.
— Percolates readily but there is some runoff in heavy rain.
— Percolates slowly. Most local rainfall ponds or runs off.
____ Other
4. Does an impervious layer prevent direct percolation of surface water to
the collector(s)? Yes _______ Ho _______ Unknown _______
5. Is the spring properly constructed to prevent entry of surface water? Yes
_______ Mo ________
6. Sediment
a. Is the spring box free of debris and sediment? Yes _____ No _______
b. When was it last cleaned (Date) ____________________________________
C. How often does it need to be cleaned? (month) _____________________
d. How much sediment accumulates between cleaning? (estimate in inches)
7. Additional coninents: _________________
—3—

-------
Infi1tration System
1. t hat are the shortest distances (vert ca1 arid horizonta’ separating the
coflector from the nearest surface water? (Feet)
2. Does turbidity of the source vary 0.2 NTU or more throughout the year?
Yes ______ No _________ Not measured ________
U yes, describe how often and how much (pH, temperature, conductivity,
etc.)
3. Additiona’ Coments ____________________________________________________
Survey Conducted By: _______________________________________ Date:
Dec sion? Surface Impacted source es ________ No _______ If no, further
evaluation needed (particulate analysis, etc.)
-4-

-------
in comparing results from sample to sample, and system to system. The
current limitations in sample collection and analytical procedures must
be considered when interpreting the results. Until standardized methods
are developed, the EPA Consensus Method included in Appendix A is
recommended as the analytical method for particulate analysis. The
following is a discussion of the significance of finding the six
indicators identified above.
Identification of a Gi&rdia cyst in any source water should be
considered conclusive evidence of direct surface water influence. There
also is general agreement that the presence of diatoms in source water is
conclusive evidence of direct surface water influence. However, it is
important that this determination be based on live diatoms, and not empty
silica skeletons which may only indicate the historical presence of
surface water.
Sluegreen, green, or other chloroplast containing algae require
sunlight for their metabolism as do diatoms. For that reason their
presence in source water should also be considered as conclusive evide cQ
of direct surface water influence.
Hoffbuhr (1986) indicates that rotifers and insect parts are
indicators of surface water. Others have pointed out though that rotifers
do not require sunlight, and not all rotifers require a food source such
as algae which originates in surface water. Their nutritional require-
ments may be satisfied by organic matter such as bacteria, or decomposing
soil organic material, not necessarily associated with surface water.
More precise identification of rotifers, i.e. to the species level, is
necessary to determine the specific nutritional requirements of the
rotifer(s) present. Further information on identifying rotifer species
and on which species require food sources originating in surface water,
would be valuable, but is not readily available at this time. Without
knowledge of which species is present, the finding of rotifers indicates
that the source is either a) directly influenced by surface water, or b)
it contains organic tatter sufficient to support the growth of rotifers.
It could be conservatively assumed based on this evidence alone that such
a source is directly influenced by surface water. However, it is
recomended that this determination be supported by other evidence, eg.
24

-------
the source is near a surface water, turbidity fluctuations are signifi-
cant 1 etc.
Insects or insect parts likewise may originate in surface water, from
the soil, or they may be airborne in uncovered sources. If insects are
observed in a particulate analysis sample, it should be confirmed if
possible that there is no other route by which insects could contaminate
the source other than surface water. For example, if a spring is sampled,
and the cover is not well constructed, it is possible that insects found
in a sample were airborne rather than waterborne. Insects which spend a
portion of their lifecycle in water are the best indicators of direct
surface water influence, for example, larvae of mayflies, stoneflies,
damselflies, and dragonflies. Terrestrial insects should not be ruled out
as surface water indicators though, since their accidental presence in
surface water is coomon.
Howell, 11989) has indicated that some insects may burrow and the
finding of eggs or burrowing larvae (eg. chironomids) may not be good
indicators of direct surf!ce water influence. For some iricerts this may
be true, but the distance which insects burrow in subsurface sediments is
expected to be small, and insect larvae are generally large in comparison
to Giardi cysts. Until further research suggests otherwise, it is
recorrended that insects or insect parts be considered strong evidence of
surface water influence if not direct evidence in and of themselves. The
strength of this evidence would be increased if the source in question is
near a surface water, and particulate analysis of the surface water found
similar insects.
Coccidia are intracellular parasites which occur primarily in verte-
brates 1 eq. animals and fish, and live in various tissues and organs
including the intestinal tract (eg. Cryptosporidlum). Though not
frequently identified by noraal particulate analysis techniques, coccidia
are good indicators of direct surface water contamination since they
require a vertebrate host or hosts and are generally large in size (10 -
20 urn or greater). Cryptosporidius is cosonly found in surface water,
but due to its small size (4— 6 ma) ills not norsally Identified without
specific antibody staining techniques.
Other macroorganisms (>7 u s) which are parasitic to animals and fish
may be found and are good indicators of surface water influence. Examples
2-9

-------
include, but are not limited to, helminths (e.g., tape worm cysts),
ascaris, and Oiphyllobothrium.
c. Samohn Method
A suggested protocol for collecting samples is listed below.
- Samohng Proceth re
Samples should be collected using the equipment outlined in the
EPA Consensus Method included in Appendix A.
— Location
Samples should always be collected as close to the source as
possible, and prior to any treatment. If samples must be taken
after disinfection, samples should be noted and analyzed as
soon as possible.
- Number
A minimum of two samples should be collected during the period
the source is most susceptible to surface water influence.
Such critical periods will vary from system to system and will
need to be determined case by case. For some systems, it may
be one or more days following a significant rainfall (eq. 2
in 24 hours). For other syste s it m y be a period of maximum
flows and stream turbidities following spring sno nelt, or
during the sunm er months when water tables are elevated as a
result of irrigation. n each case, particulate samples should
be collected when the source in question is most effected. A
surrogate measure such as source turbidity or depth to water
table may be useful in making the decision to monitor. If
there is any ambiguity in the particulate analysis results,
additional samples should be collected when there is the
greatest likelihood that the source will be contaminated by
surface water.
- Volume
Sample volume should be between 500 and 1000 gallons, and
shculd be collected over a 4 to 8 hour time period. It is
preferable to analyze a similar (+1- 10%) volume of water for
all sources,, preferably a large volume, although this may not
always be possible due to elevated turbidity or samplin
logistics. The volume filtered should be recorded for al
sa les.
d. Other Indicators
A number of other indicators could be used to provide supportive
evidence of surface Influence. While particulate analysis probably
provides the most direct evidence that pathogens from surface water could
be migrating into a ground water source, other parameters such as
2-10

-------
turbidity, temperature, pH and conductivity could provide supportive, but
less direct, evidence.
Turbidity fluctuations of greater than 0.5 - 1 NTU over the course
of a year may be indicative of surface water influence. Considerable
caution should be used when evaluating turbidity changes though, since the
turbidity cQuld be caused by very small particles (c turn) not originating
in a surface water or it could be that larger particles are being filtered
out and only the very smallest particles migrate into the water source.
Only ground water sources at risk to contamination from Giardia or other
large pathogens (> 7 urn) are subject to the SWTR requirements.
Temperature fluctuations may also indicate surface water influence.
Fortunately these are easy to obtain and if there is a surface water
within 500 feet of the water source, measurements of both should be
recorded for comparison. Large changes in surface water temperature
closely followed by similar changes in source temperature would be
indicative of surface water influence. Also, temperature changes (in
degrees F) of greater than 15 to 23% over the course of a year appear to
be a ch r :teristic of some sources influenced by surface water (Randall,
1970). Changes in other chemical parameters such as pH, conductivity,
hardness,etc. could also be monitored. Again, these would not give a
direct indication of whether pathogens originating in surface water were
present, but could indicate whether the water chemistry was or was not
similar to a nearby surface water andfor whether source water chemistry
changed in a similar pattern to surface water chemistry. At this time no
numerical guidelines are available to differentiate what is or is not
similar, so these comparisons are more qualitative than quantitative.
8. Seasonal Sources
Some sources way only be used for part of the year 4 for example
during t i m suser months when water usage Is high. These sources should
not be excluded from evaluation and, like other sources, should be
evaluated during their period(s) of highest susceptibility. Particular
attention should be given to those sources which appear-to be directly
influenced by surface water during part of the year. There may be times
during which these subsurface water sources are not influenced by surface
water and other times when they are part or all surface water. If that
2—11

-------
is the case, then it is critical that careful testing be done prior to,
thiring and at the end of the use of the source. This should be done over
several seasons to account for seasonal variation. in practice, it is
preferable to use sources which are less vulnerable to contamination since
susceptible sources will necessitate ongoing monitoring and close
attention to operation.
C. Modification of Sources
Sources directly influenced by surface water may be altered in some
cases to eliminate the surface water contamination. Primacy Agencies may
elect to aflow systems with such sources to modify the construction of the
source and/or the area surrounding the source in an effort to eliminate
surface water contamination. Since this could be expensive and take
considerable time to evaluate for effectiveness, careful consideration
should be given to the decision to modify a source. in deciding whether
source modification is appropriate, systems and Primacy Agencies should
consider the following points:
- Is the cause of the surface water contamination known? If the
specific cause or point of surface water contamination is not
known, it will not be possible to determine an effective
control strategy. Further, there may be several reasons why
the source is susceptible to direct surface water influence.
For example, an infiltration gallery may receive surface water
because some of its laterals are exposed in the bed of a nearby
stream, and also because laterals distant from the stream are
shallow and are affected by surface runoff. Simply modifying
or eliminating one or the other set of laterals in this case
would not entirely eliminate surface water influence.
- What is the likelihood that modification of the source will be
effective? Assuming that the source of contamination has been
identified, the expected effectiveness of control measures
should be evaluated. If the cause is relatively evident, a
crack in a well casing or an uncovered spring box for example,
then there is a high degree of confidence that an effective
solution could be developed. Should the nature of the
contamination be more diffuse, or widespread, then the merits
of spending time and money to modify the source should be
carefully considered. In the case of the example above,
eliminating the use of the laterals under the stream will solve
part of the problem. However, without considerably more
hydrogeologic information about the aquifer and the placement
of the other laterals it is not clear what, if any, control
measures would effectively eliminate direct surface water
influence in those laterals distant fr the stream.
2-12

-------
If a source is ident fied as being directly influenced by surface
nater, and it is decided to attempt to modify t, intenm disinfection
practices which will ensure at least 99.9% inactivation of Giardia should
be considered. Methods and levels of disinfection which can be used to
achieve such removals can be found in S141.72 (a) of the SWTR and in
Section 3.2 of this manual.
A partial listing of types of modifications which could be undertaken
includes:
- Diverting surface runoff from springs by trenching, etc.
- Redeveloping springs to capture them below a confining layer.
- Covering open spring collectors.
— Reconstructing wells to install sanitary seals, and/or to
screen them in a confined (protected) aquifer.
— •Repairing cracks or breaks in any type of source collector that
allows the entry of surface contaminants.
- Discontinue the use nf infiltration laterals which intercept
surface water.
An extended period of monitoring should follow reconstruction (eg.
through at least two years or critical periods) to evaluate whether the
source is still directly influenced by surface water. Preferably
particulate analysis would be used to make such evaluations, but it may
be helpful to use simpler measures, such as temperature and turbidity, as
screening tools. Longer term monitoring at critical times may also be an
appropriate agreement between the system and the Primacy Agency if there
is still doubt about the long term effectiveness of the solution.
If modification Is not feasible, another alternative to avoid having
to comply with the SWTR may be to develop a new well either deeper or at
a different location.
2.2 Treatment Reauirements
According to the SWTR, oil co Inity and nonco inity public water
systems which use a surface water source or a ground water under the
direct influence of a surface water must achieve a minimum of 99.9 percent
(3-log) removal andfor Inactivation of Giardia cysts, and a minimum of
2-13

-------
gg•gg percent (4-log) removal and/or inactivation of viruses. In the SWTR
and this manual, ‘viruses” means viruses of fecal origin which are
infectious to humans by waterborne transmission. Filtration plus
disinfection or disinfection alone may be utilized to achieve these
performance levels, depending on the source water quality and site
specific conditions. The SWTR establishes these removal and/or inactiva-
tion require ments based on Giardia and viruses because this level of
treatment will also provide protection from heterotrophic plate count
(WPC) bacteria and Legionella 2 as required in the SDWA amendments.
Guidelines for meeting the requirements of the SWTR are provided in
the remainder of this manual as outlined in Section 1. All systems must
meet the operator qualifications presented in Section 2.3.
2.3 Ooerator Personnel Oualifications
The SWIR requires that all systems must be operated by qualified
personnel. It is recorrended that the Primacy Agency set standards for
operator qualifications, in accordance with the system type and size. In
order to accomplish this, the Primacy Agency should develop a method of
evaluating an operator’s competence in operating a water treatment system.
Primacy Agencies which do not currently have a certification program are
thereby encouraged to inpiement such a program. An operator certification
program provides a uniform base for operator qualifications and an
organized system for evaluating these qualifications.
It is reconrended that pLant operators have a basic knowledge of
science, mathematics and chemistry involved with water treatment and
supply. The minimum requirements for at least one key staff member should
include an understanding of:
— The principles of water treatment and distribution and their
characteristics
— The uses of potable water and variations in its demand
— The importance of water quality to public health
2 In the SlUR and this manual “ Legionella means a genus of
bacteria, some species of which have caused a type of pneumorna
called Legionnaires Disease; the etiologic agent of most cases
of Legionnaires Disease examined has been L gpeumoohila .
2—14

-------
- The equipment, operation and maintenance of the distribution
system
— The treatment process equipment utilized, its operational
parameters and maintenance
- The principles of each process unit (including the scientific
basis and purpose of the operation and the mechanical
components of the unit)
- Performance criteria such as turbidity, total colifonn, fecal
coliform, disinfectant residual, p11, etc. to determine
operational adjustments
— Cotmnon operating problems encountered in the system and actions
to correct then
- The current National Primary Drinking Water Regulations, the
Secondary Drinking Water Regulations and monitoring and
reporting requi rements
- Methods of sample collection and sample preservation
- Laboratory equipment and tests used to analyze samples (where
appropri ate)
- The use of laboratory results to analyze plant efficiency
- Record keeping
— Customer relations
— Budgeting and supervision (where appropriate)
Training in the areas listed above and others is available through
the American Water Works Association (AWWA) training course series for
water supply operations. The course series includes a set of four
training manuals and one reference book as follows:
- Introduction to Water Sources and Transmission (Volume 1)
- Introduction to Water Treatment (Volume 2)
- Introduction to Water Distribution (Volume 3)
- Introduction to Water Quality Analyses (Volume 4)
— Reference Handbook: Basic Science Concepts and Applications
— Instructor Guide and Solutions Manual for Volumes 1, 2, 3 and
4
2-15

-------
These manuals are available through the American Water Works Associa-
tion . 5666 West Quincy Avenue. Denver, Colorado 80235 USA, (303) 794—7711.
The State of California also offers a series of training manuals for
water treatment plant operators prepared by the California State
University School of Engineering in Sacramento. The manuals include:
1. Water Supply System Operation. (1 Volume)
2. Water Treatment Plant Operation. (2 Volumes)
These operator training manuals are available from California State
University, Sacramento, 6000 3 Street, Sacraniento, California 5819, phone
(916) 454-6142.
Completion of an established training and certification prograrnwifl
provide the means of assuring that the operators have received training
in their respective area, and are qualified for their position. The
education and experience requirements for certification should be
coitensurate with the size and the complexity of the treatment system.
At the present time, some states have instituted a certification program
while others have not. Following is a sunuary of the basic contents of
a certification program, which can serve as a guide to the Primacy Agency
in developing a complete program.
- Board of examiners for the development and implementation of
the program.
— Classification of treatment facilities by grade according to
the size and technology of the facilities.
- Educational and experience requirements for operators of the
various treatment facilities according to grade.
- A written/oral examination to determine the knowledge, ability
and judgement of the applicants with certification obtained
upon receiving a passing grade.
- Renewal program for the license of certification, including the
requirement of additional coursework or participation in
workshops.
The certification program should provide technically qualified
personnel for the operation of the plant.
The extensive responsibility which is placed on the operating
personnel warrants the development of an outline of the responsibilities
and authority of the personnel members to aid them in the efficient
2-16

-------
operation of the plant. The major responsibilities r hich should be
delegated in the outline of responsibilities include: the normal
day-to-day operations 1 preventive maintenance, field engineering, water
quality monitoring, troubleshooting, emergency response, cross—connection
control, implementation of improvements, budget formulation, response to
complaints and public/press contact. A reference which the Primacy Agency
may utilize in developing the outline is “Water Utility Management
Practices” published by #WWA,
2-17

-------
3. CR iTERIA FOR SYSTEMS NOT FILTERING
The provisions of the Surface Water Treatment Rule (SWTR) require
that filtration must be included in the treatment train unless certain
criteria are met. These criteria are described in this chapter. They
include:
Source Water Quality Ccnditio
I. Colifonn concentrations (total or fecal).
2. Turbidity levels.
Qisinfection Criteria .
I. Level of disinfection.
2. Point of entry disinfection.
3. DIstribution system disinfection.
4. Disinfection redundancy or automatic shutoff.
ite-Soeci f Ic Criteria
1. Watershed control program.
2. On—site inspections.
3. No waterborne disease outbreaks.
4. Complies with the total coliform MCL.
5. Complies with the total Trihalomethane (11)04) regulation.
Currently this only applies to systems serving more than
10 .000 people.
The purpose of this section is to provide guidance to the Primacy
Agency for determining compliance with these provisions.
3.1 Source Water Qualit y Criteda
The first step in determining If filtration Is required for a given
surface water supply is to determine whether the supply meets the source
water quality criteria as specified in the SWTR. If the supply does not
meet the source water quality criteria, changes In operation to meet the
3 - 1

-------
site-specific criteria may improve the water quality so that the source
criteria will be met. However 1 if the Primacy Agency believes that the
source water quality criteria and/or the site-specific criteria cannot be
met, or that filtration is appropriate regardless, the Primacy Agency may
require the installation 0 f filtration without a complete evaluation to
determine whether the system meets all the criteria required to avoid
filtration.
Samoling Location
The SWTR requires that source water samples be collected at a loca-
tion just prior to the upoint of disinfectant applicatIon, i.e., where
the water is disinfected and no longer subject to surface runoff. For
example, a system which has multiple reservoirs in series, where each of
the reservoirs has previously been disinfected and receives surface
runoff, must take the raw water sample(s) just prior to the point of
disinfection or disinfection sequences used for calculating the CT
[ disinfectant residual (mg/I) x contact time (mm.)]. Olsinfected water
in reservoirs receiving surface runoff cannot be counted toward CT credit.
It is also not appropriate for systems to monitor the source water after
the “point of disinfectant applicatlon even if disinfection from this
point is not used for calculating CT credit.
3.1.1 Coliforni Concentrations : The SWTR states that, to avoid
filtration, a system must demonstrate that either the fecal colifonn
concentration is less than 20/100 ml the total coliform concentration
is less than 100/100 ml in the water prior to the point of disinfectant
application in 90 percent of the samples taken during the six previous
months. Where monitoring for both parameters has been or Is conducted,
the rule requires that only the fecal coliform limit be met. However, EPA
reco ends that the analytical results for both total coliforms and fecal
col1for be reported. In addition, If the turbidity of a surface water
source Is greater than 5 NTU and the surface source Is blended with a
ground water source to reduce the turbidity, EPA recomeends that the high
turbidity water prior to blending meet the fecal coliform source water
quality criteria.
3 .2

-------
Elevated coliform levels in surface water indicate higher probabili-
ties of fecal contamination, some of which could be protected from
exposure to disinfection by embodiment in particulate matter. Blending
of the surface water with ground water to reduce coliform levels may
obscure the indication of such possible effects. Thus, EPA does not
recourend blending to reduce coliform levels in the source water.
Furthermore, EPA does not reconmiend blending to reduce turbidity levels
in cases where elevated fecal contamination may be masked.
Ongoing monitoring is required to ensure that these requirements are
continually met. The samples may be analyzed using either the multiple
tube fermentation method or the membrane filter test (M V) as described in
the 16th Edition of Standard Methods.
Samol ing Frecuency
Minimum sampling frequencies are as follows:
Population Served Coliform Samoles/Week
500 1
501-3 ,300 2
3,301-10 .000 3
10.001-25,000 4
>25 ,000 5
Grab samples must be taken on dIfferent days. In addition, one
sample must be taken every day during which the turbidity exceeds 1 NTU,
unless the Primacy Agency determines that the system, for logistical
reasons outside the system’s control, cannot have the sample analyzed
within 30 hours of collection. If taken, these samples count towards the
weekly sampling requirement. Also, under the Total Coliform Rule, systems
must take one colifors sample in the distribution system near the first
service connection withIn 24 hours after a source water turbidity
measurement exceeds 1 KTU. This measurement must be included in the total
colifors co liance determination. The purpose of these requirements is
to ensure that the monitoring occurs during worst case conditions.
The initial evaluation of the source water quality Is based on the
data from the previous 6 months. After the initial evaluation, systems
must continue to conduct sampling each month to demonstrate compliance
3-3

-------
with the source water quality criteria on an ongoing basis. If the
cr terlon has not been met, the system must filter.
Use of Historical Data Base
Some systems may already monitor their source water for total and/or
feca l coliform concentration. The resulting historical data base may be
sufficient for the Primacy Agency to make the initial determination of
whether the system meets the source water quality criteria. The
historical data base is considered sufficient for making this detennina-
tion if:
— The raw water sampling location is upstream of the point of
disinfectant application as previously defined.
- The monthly samples represent at least the minimum sampling
frequency previously mentioned.
- The sampling period coven at least the previous six months.
3.1.2 Turbidity Levels : To avoid filtration, the turbidity of the
water prior to disinfection cannot exceed 5 NTU, on an ongoing basis,
based on grab samples collected every four hnurs (or more frequently) that
the system is in operation. A system nay substitute continuous turbidity
monitoring for grab sample monitoring if it validates such measurements
for accuracy with grab sample measurements on a regular basis, as
specified by the Primacy Agency.’ If a public water system uses continuous
monitoring, it must use turbidity values recorded every four hours (or
some shorter regular time Interval) to determine whether it meets the
turbidity limit for raw water. A system occasionally may exceed the 5 NTU
limit and still avoid filtration as long as (a) the Primacy Agency
determines that each event occurred because of unusual or unpredictable
circumstances and (b) as a result of this event, there hive not been more
Validation should be performed at least twice a week based on the
procedure outlined in Part 214A im the 16th Edition of Standard Methods.
Although the 17th EdItion is available, the 16th EditIon is that which
is referred to In the rule. Improper installation of continuous
monitors may allow far air bubbles to enter the monitor resulting i t t .
false turbidity spikes. To avoid air bubbles reaching the turbidimeter,
the sample tan should be installed below the center line of the pipe
and an air re’ease valve may be Included on the sample line.
3-4

-------
than two such events in the past twelve months the system served water to
the public or more than five such events in the past 120 months the system
served water to the public. An Neventli is defined as a series of
consecutive days in which at least one turbidity measurement each day
exceeds S 1 1 1 1 1.
it is important to note that every event, i.e., exceedance of the
S MTU limit, regardless of whether the system must filter as a conse-
quence, constitutes a violation of a treatment technique requirement.
For example, if the turbidity exceeded 5 NTU in at least one measurement
each day for three consecutive days, this would constitute one event and
one treatment technique violation. If this was the third event in the
past i2 months the system served water to the public, or the sixth event
in the past 120 months the system had served water to the public, the
system would also be required to install filtration. In all cases, the
system must inform the Primacy Agency when the turbidity exceeds S MU as
soon as possible, but no later than the end of the next business day.
The Primacy Agency should evaluate additional data from the utility
to determine the significance of the event with respect to the potential
health risk to the coztununity and determine whether a boil water notice is
necessary. The additional data may include raw water fecal coliform
levels, duration and magnitude of the turbidity excursion, nature of the
turbidity (organic or inorganic), disinfectant residual entering the
system during the excursion and/or colifora levels in the distribution
system following the excursion. Soil water notices are not required under
the SWTR although they may be Issued at the discretion of the Primacy
Agency.
In order to determine if the periods with turbidity greater than
5 EU are unusual or unpredictable, it is reco ended that in addition to
the historical turbidity data, the water purveyor should collect and
provide to the Primacy Agency current and historical Information on flows,
reservoir water levels, climatological conditions, and any other informa-
tion that the Primacy Agency dens relevant. The Primacy Agency will then
evaluate this information to determine if the event was unusual or
unpredictable. Exa les of unusual or unpredictable events include:
3-5

-------
unpredictable. Examples of unusual or unpredictable events include:
avoid a high turbidity event by:
Use of an alternate source which is not a surface water and
does not have to meet the requirements of the SWTR.
- Use of an alternate source which is a surface water and which
does meet the requirements of the SWTR.
- Utilization of stored water to supply the conrunity until the
source water quality meets the criteria.
3.2 Disinfection Criteria
3.2.1 InactivatIon Reouirements
To avoid filtration, a system must demonstrate that it maintains
disinfection conditions which inactivate 99.9 percent of Glardia cysts and
gg•gg percent of viruses every day of operation except any one day each
month. If the disinfection conditions provide less than these inactiva—
tions during more than one day of the month, the system is In violation
of a treatment technique requirement. If the system incurs such a
violation during any tt months in the previous 12 months, the system must
instafl filtration, unless one of the violations was caused by unusual and
unpredictable circumstances as determined by the Primacy Agency. Systems
with three or more violations in the previous 12 months must Install
filtration regardless of the cause of the violation. To demonstrate
adequate inactivat lons, the system must monitor and record the disinfec-
tant(s) used, disinfectant residual(s), disinfectant contact time(s), p 14
(for chlorine), and water temperature, and use these data to determine if
it is meeting the minima total Inactivation requirements in the rule.
A nSer of disinfectants are available, including ozone, chlorine,
chlorine dioxide and chloramines. The SWIR prescribes CT [ C, residual
disinfectant concentration (mg i 1) x 1, contact time (m m)] levels for
these disinfectants which will achieve different levels of Inactivation
under various conditions. The disinfectant(s) used to meet the inactiva-
tion requirements is identified as the primary disinfectant throughout the
remainder of this docuent
To determine co lfance with the inactivation requirements, a system
mist calculate the CT value(s) for its disinfection conditions during peak
3-6

-------
hourly flow once each day that it is delivering water to its customers.
For the purpose of calculating CT value, T is the time (in minutes) it
takes the water, during peak hourly flow, to move between the point of
disinfectant application and a point where, C, residual disinfectant
concentration is measured prior to the first customer. Residual
disinfectant concentration is the concentration of the disinfectant (in
mg/L) at a point before or at the first customer. Contact time in
pipelines must be calculated based on plug flow (i.e., where all water
moves homogeneously in time between two points) by dividing the internal
volume of the pipeline by the peak hourly flow rate through that pipeline.
Contact time within mixing basins, settling basins storage reservoirs, and
any other tankage must be determined by tracer studies or an equivalent
method as determined by the Primacy Agency. The contact time determined
from tracer studies to be used for calculating CT is T 10 . T 10 is the
detention time corresponding to the time for which 90 percent of the water
has been in contact with at least the residual concentration, C. Guidance
for determining contact times for basins is provided in Appendix C.
The first customer is the point at which finished water is first
consumed. In many cases this will include the treatment plant itself.
This definition of first customer pertaining to the point of first
consumption assures that the water has received the required disinfection
to provide protection from microorganisms for all consumers. Peak hourly
flow should be considered as the greatest volume of water passing through
the system during any one hour in a consecutive 24 hour period. Thus, it
is not meant to be the absolute peak flow occurring at any instant during
the day.
Systems with only one point of disinfectant application may
determine the total inactivation based on one point of residual measure-
ment prior to the first customer 1 or on a profile of the residual
concentration after the point of disinfectant application. Methods of
disinfection measurement are presented in Appendix D. The residual
profile and the total inactivation is calculated as follows:
— Measure the disinfectant residual, Crat any nSer of points
within the treatment train.
3-7

-------
- Determine the travel time, 1, between the point of disinfec-
tant application and the point where C is measured for the
first section. For subsequent measurements of C, I is the
time it takes for water to move from the previous “C”
measurement point to this point of measurement.
- Calculate CI for each point of residual measurement
- Determine the inactivation ratio (CT 1 /CT 99 ) for each sec-
- Sum the inactivation ratios for each section, i.e. Cl /CT
+ C 2 T 2 /CT 99 + C 0 1 0 /CT 99 to determine the total inac t?vadon
rat 10.
If the total inactivation ratio (sum (CT 1 /CI 99 )) is equal to or greater
than 1.0, the system provides greater than 99.9 percent inactivation of
Ciardia cysts), and the system meets the disinfection performance re-
quirement. Further explanation of CT calculations is presented in Section
3.2.2.
Systems need only calculate one CT (CT 1 1 ) each day, for a point at
or prior to the first customer; alternatively they have the option of cal-
culating mumerous CTs after the point of disinfectant application but
prior to the first customer to detenine the inactivation ratio. Profil-
ing the residual gives credit for the higher residuals which exist after
the disinfectant is applied but before the first customer. Profiling the
residual may not be necessary if one CT is calculated and this
exceeds the applicable CT 99 . In this case, the system is meeting the
disinfection performance requirement. For systems with a very low oxidant
demand in the water and long contact times, this approach may be the most
practical to use.
For systems with multiple points of disinfectant application 1 such
as ozone fo1lowod by chlorine, or chlorine applied at two different points
in the treatment train, the inactivation ratio of each disinfectant
2 c is the CT value required to achieve 99.9 percent or 3-log Giardia
cj4’t’inactiueticn for the conditions of p14, t erature and residual
concentration for each section. A section is the portion of the system
with a measurable contact time between two points of disinfection
application or residual monitoring.
3-8

-------
section prior to the first customer is used to eter11Iine the total
inactivation ratio. The disinfectant residual of each disinfection
section and the corresponding contact time must be measured at some point
prior to the subsequent disinfection application point(s) to determine the
inactivation ratio for eacn section, and whether the total inactivation
ratio is 1.0 or more. For ex .mp1e, if the first disinfection section
provided an inactivation ratio of 2/3 (or 99 percent inactivation) and the
second disinfection section provided an inactivation ratio of 1/3 (or 90
percent inactivation), the total inactivation ratio would equal 1.0 (2/3
+ 1/3 . 1) indicating that 99.9% inactivation was provided and the
disinfection requirements are met. Further explanation of the determina-
tion of total inactivation provided is contained in Section 3.2.2.
Maintaining Inactivation Level
The SWIR establishes CTs for chlorine, chlorine dioxide, ozone and
chioramines which will achieve 3-log inactivations of Gtardia cysts and
at least 4-log Inactivation of viruses. Appendix E presents CTs for these
and other log inactivations. A system must demonstrate compliance with
the inactivation requirements based on conditions occurring during peak
hourly flow. Since a system generally can only identify peak hourly flow
after it has occurred, hourly residual measurements during the day are
suggested. If the sampling points are remote, or manpower is limited and
collection of hourly grab samples is impractical, continuous monitors may
be installed. In cases where continuous monitors are impractical, the
Primacy Agency may establish an acceptable monitoring program on a
case-by-case basis; where possible this should be based on historical flow
patterns. Measurements for the hour of peak flow can then be used In
calculating CT. The pH (for systems using chlorine) and temperature must
be determined daily for each disinfection sequence prior to the first
customer.
Since the system’s Inactivation Is determined during peak hourly
flow, the disinfectant dosage applied to meet CT requirements ay not be
necessary during lower flow conditions. Continuing to apply a disinfec-
tant dosage based on the peak hourly flow could possibly result in
increased Ieve s of disinfectant by-products, Including TTHMs and
3-9

-------
increased costs. Under lower flow conditions, a higher contact time is
available and a lower residual may provide the CT needed to meet the
inactivation requirements. The system may therefore choose to adjust the
disinfectant dose with changes in flow. The system should, however,
maintain a disinfectant residual which will still provide a 3-log
inactivation of Giardia cysts and a 4-log inactivation of viruses at
non-peak hourly flows. The system should therefore evaluate the residual
needed to provide the required inactivation under different flow
conditions and set the dosage accordingly. The following provides an
example of maintaining the required inactivation.
Examole
A 5 mgd non-filtering system disinfecting with free chlorine at one
point of application, has a contact time of 165 mInutes during a peak flow
of 5 MCD. The flow varies from I to 5 MGO. The pH and temperatures of
the water are 7 and 5 C, respectively. At a residual of 0.9 mgIL, a CT
of 148 mg/I-mm is ‘required to meet the disinfection requirements. The
CT for 0.9 mg/L residual is determined by straight line interpolation
between 0.8 mg/I and 1.0 mg/I residuals. Under lower flow conditions, the
available contact time is longer and a lower residual would provide the
required disinfection. Based on existing contact time and using the
appropriate CT tables (in this case, Table E-2) in Appendix E for a 3—log
Giardia cyst inactivation, the required disinfection would be provided by
maintaining the following chlorine residuals for the indicated flow:
Contact CT (mg/L-.ln) Free Chlorine
Flow (MCD) Time (mm) Required Residual (malL )
5 165 148 0.9
4 206 145 0.7
3 275 143 0.6
2 412 139 0.4
1 825 139 0.2
This table Indicates the variation of residuals needed for the
syste. to provide the required inactivation. For chlorine, the disinfec-
tant residual cannot be adjusted In direct proportion to the flow because
the CT needed for disinfection Is deper ent upon the residual. Since It
Is not practical to continuously adjust the residual and, since a
.3-10

-------
disinfection level for a 3-log Giardia cyst inactivation must be
maintained under all flow conditions, it is suggested that the flow
variation at the utflity be divided into ranges and the residual needed
at the higher flow rate of each range be maintained for all flows within
the range to ensure the required disinfection. The following flow ranges
and residuals are suggested for the system:
Free Chlorine
Flow Ranue (MGD) Residual (mg/L I
1- 1.9 0.4
2 -3.9 0.6
4 - 5 o.g
By maintaining these residuals, the utility is ensuring the provision of
the required disinfection while minimizing the disinfectant application,
which should result in lower disinfection by—products and costs.
Although these residuals will meet the inactivation requirements,
maintaining a residual in the distribution system must also be considered.
If no other point of disinfection exists prior to the distribution system,
the residual for disinfection must be maintained at a level which will
also provide a residual throughout the distribution system. The complete
range of flows occurring at the plant should be evaluated for determining
the required residual. A utility may establish the residual requirements
for as many flow ranges as is practical.
The CTh determined from the daily system data should be compared to
the values in the table for the pH and te erature of the water, to
determine If the required CT has been achieved. Only the analytical
methods prescribed in the SlUR, or otherwise approved by EPA, may be used
for measuring disinfectant residuals. Methods prescribed In the SWTR are
listed in Appendix 0. The Appendix also contains a paper which describes
monitoring methods for various disinfectants and conditions.
The Primacy Agency should make periodic checks on Its utilities to
assure that they are maintaining adequate disinfection at non-peak flow
condition.
3-11

-------
Meeting the Inactivation Reouirement using Free Chlorine
When free chlorine is used as a disinfectant, the efficiency of
inactivation is influenced by the temperature and pH of the water. Thus,
the measurement of the temperature and pH for the determination of the CT
is required. The SWTR provides the CT requirements for free chlorine at
various temperatures and pHs which may occur in a source water. These
values are presented in Table E-1 through Table E-7 in Appendix E. The
basis for these values is discussed In Appendix F. For free chlorine, a
3-log inactivation of Gi ardia cysts wifl provide greater than a 4-log
inactivation of viruses, thus meeting the SWTR inactivation requirements.
As indicated in Table E-2, a raw water temperature of 5 C, a pH of
7.0, and a residual chlorine concentration of 1.4 mg/I require a CT of
155 mg/I-mm to provide a 3-log Inactivation of Glardia cysts. Therefore,
to meet the inactivation requirement under these conditions with one point
0 f residual measurement, a contact time of 111 mInutes ((155 mgfL-min)/
(1.4 mg/I)] prior to the first customer would be required.
Meeting the Inactivation Requirement Using Chloremine
Chioramines are a much weaker oxidant than free chlorine, chlorine
dioxide and ozone. The CT values for chloramines presented in Table E-12
are based on disinfection studies using preformed chioramines and j vitro
excystation of Giardla nuns cysts (Rubin, 1988). No safety factor was
applied to the laboratory data on which the CT values were based since EPA
believes that chioraminatlon, conducted In the field, Is more effective
than using preformed chloramines.
In the laboratory testing using preformed chionamines, ameonia and
chlorine were reacted to form chioramines before the addition of the
microorganisms. Under field conditions, chlorine Is usually added first
followed by aonia addition further downstream. Also even after the
addition of on1a, same free chlorine residual may persist for a period
of time. Therefore, free chlorine Is present for a period of time prior
to the formation of chiorailnes. Since this free chlorine contact time
Is not duplicated in the laboratory when testing with preformed
chioramines, the CT values obtained by such tests may provide conservative
values when c ared to those CTs actually obtained In the field with
3-12

-------
chlorine applied before amonia. Also 1 other factors such as mix ng in
the field (versus no mixing in the laboratory) may contribute to
disinfection effectiveness. For these reasons, systems using chlorainines
for disinfection may demonstrate effective disinfection in accordance wth
the procedure in Appendix G in lieu of meeting the CT values in Appendix
E.
If a system uses chioramines and is able to achieve the CT values
for 99.9 percent inactivation of Giardia cysts, it is not always
appropriate to assume that 99.99 percent or greater inactivation of
viruses was also achieved. New data indicate that Hepatitis A virus is
mare sensitive than Giardia cysts to Inactivation by preformed chloramines
(Sobsey, 1988). The CT values required to achieve 99.99 percent
inactivation of Hepatitis A with preformed chloramines are lower than
those needed to achIeve 99.9 percent Inactivation of Glardia cysts. These
data contrast with other data which indicate that rotavirus is more
resistant than Giardia cysts to preformed chioramines (Hoff, 1986))
However rotavirus is very sensitive to inactivation by free chlorine,
much more so than Hepatitis A (Hoff, 1986;1 Sobsey, 1988). If chlorine is
applied prior to amonia, the short term presence of free chlorine would
be expected to provide at least 99.99 percent inactivation of rotavirus
prior to the addition of amonia and subsequent formation of chloramines.
Thus, EPA believes It is appropriate to use Hepatitis A data, in lieu of
rotavirus data, as a surrogate for defining minimum CT values for
inactivation of viruses by chioramines, under the condition that chlorine
is added to the water prior to the addition of a onla.
A system which achieves a 99.9 percent or greater inactivation of
Glardia cysts with chloraaines can be considered to achieve at least 99.99
percent Inactivation of viruses, provided that chlorine Is added to the
water prior to the addition of au onia. Table E-13 provides CT values for
CT values In excess of 5 OO0 are required for a 4-log inactivation of
rotavirus by preformed chloraalnes but no minimum CT values have been
determined.
CT values ranging from 0.025 to 22 achieve 99 percent Inactivation of
rotavirus by free chlorine at pH • 6 -10 and 4 — 5C (Hoff, L986).
3-13

-------
achieving different levels of virus inactivation. However, if aninonia is
added first, the CT values in the SWTR fcr achieving 99.9 percent
inactivation of Giardia cysts cannot be considered adequate for achieving
99.99 percent inactivation of viruses.
Under such cases of chloranine production, the SWTR requires systems
to demonstrate through on-site challenge studies, that the system is
achieving at least a 4—log inactivation of viruses. Guidance for
conducting such studies is given in Appendix G. Once conditions for
achieving a 4-log Inactivation of viruses has been established, the
Primacy Agency should require systems to report their disinfection
operating conditions on an ongoing basis. These conditions should verify
that the system is operating at CT values in excess of that needed to
achieve a 4—log virus inactivation or 3—log Glardia cyst inactivation,
whichever is higher.
Meeting the Inactivation Reouirement Using Chlorine Dioxide
Under the SWTR, the CT values for the inactivation of Giardia cysts
using chlorine dioxide are independent of pH. Under the SWIR the only
para ’ ,ter affecting the CT requirements associated with the use of
chlorine dioxide is temperature. Table £4 In Appendix E presents the
chlorine dioxide CT values required for the inactivation of Glardia cysts
at different temperatures. The basis for these CT values is discussed in
Appendix F. Systems which use chlorine dioxide are not required to
measure the pH of the disimfected water for the calculation of CT. For
chlorine dioxide, a 3-log inactivation of Giardia cysts will generally
result in greater than a 4-log virus inactivation, and assure meeting the
SWTR inactivation requirements. However, for chlorine dioxide, unlike
chlorine vthere this relationship always holds true, at certain tempera-
tures, the 4-log virus CTs may be higher than the 3-log Giardia cyst Cs.
The Primacy Agency say allow lower CT values than those specified
in the SVTR for individual systems based on information provided by the
system. Protocols for demonstrating effective disinfection at lower C l
values is provided in Appendix G.
As indicated in Tables (-8 and (-9, the CT requirements for chlorine
dioxide are substantially lower than those required for free chlorine.
3-14

-------
However, chlorine dioxide is not as stable as free chlorine or ch lorarnines
in a water system and may not be capable of providing the required
disinfectant residual throughout the distribution system. In addition,
out of concern for toxicological effects, EPA ’s current guideline is that
the sum of the chlorine dioxide, chlorate and chlorite residuals, be less
than 1.0 mg/L at all consumer taps. This guideline may be lowered as more
health effects data become available. These concerns further reduce the
feasibility of using chlorine dioxide as a secondary disinfectant for
distribution systems. Therefore 1 the use of chlorine dioxide as a primary
disinfectant may result in the need for the application of a secondary
disinfectant 1 such as chlorine or chIoramines, that will persist in the
distribution system and provide the required residual protection.
Meeting the Inactivation Requirement Using Crone
A third disinfectant to Inactivate Glardia cysts and viruses is
ozone. As with chlorine dioxide, under the SWTR, the CT values for ozone
are independent of pH. Tables E-l0 and f-li present the CT requirements
for ozone at different source water temperatures. The SWTR does not
require the measurement of the finished water p H for purposes of CT
calculations. The basis for the CT values for ozone is given In Appendix
F. As for free chlorine, a 3-log Giardia cyst inactivation with ozone
will result In greater than a 4-log virus inactivation. The Primacy
Agency may allow lower CT values for individual systems based on
information provided by the system that demonstrates that lower CT values
than those specified In the rule achieve the same inactivation efficien-
cies. Reconnended protocol for demonstrating effective disinfection is
provided in Appendix 6.
Ozone is extremely reactive and dissipates quickly after applica-
tion. Therefore, a residual 5 cam only be expected to persist a short time
The residual must be measured using the Indigo Trisulfonate Method
(Bader & Hoigne, 1981) or automated methods which are calibrated in
reference to the results obtained by the Indigo Trisulfonate method,
on a regular basis as determined by the Primacy AQency. The Indigo
Trisulfonate method is included in the 17th Edition ot Standard Methods .
This method is preferable to current standard methods because of the
selectivity of the Indigo—reagent In the presence of most interferences
found in ozonated waters. Indigo trisulfonate is the Indicator used
3-15

-------
after apphcation. In addition to this, the application of ozone to water
is dependent on mass transfer. For these reasons, the method of CT
determination used for the other disinfectants is impractical for ozone.
The CTcalc must be determined for the ozone basin alone. The portion of
the ozone basin where the ozone is applied wifl be referred to as the
contactor, and the portion of the basin where ozone is no longer applied
will be referred to as the reactor.
For many ozone contactors, the residual in the contactor will vary
in accordance with the method and rate of application, and there will be
a portion of the contactor which does not contain an ozone residual. As
previously indicated, the CT value is based on the presence of a known
residual during a specific contact time. Thus disinfection credit is only
provided for the time, T during which a residual is present. The
method of monitoring the residual will have an Impact on the determination
of the CT for each basin, thereby affecting the disinfection credit.
In addition to the difficulty in determining the ozone residual for
the CT calculation, the contact time will vary between basins depending
on their configuration. Several types of devices are available for adding
ozone to water including porous diffusers, submerged turbines, injector,
packed towers and static mixers. Each type of device can be used in
either single or multiple chamber contactors. The flow through a single
chamber turbine unit will approximate a completely mixed unit, while flow
through a single chamber diffused contactor, or a multiple chamber
diffused contactor, will more closely represent plug flow. However, the
contact time for the contactor should be determined through a tracer study
in this test method. The ozone degrades an acidic solution of indigo
trisulfonate In a 1:1 proportion. The decrease In absorbance is linear
with increasing ozone concentrations over a wide range. Malonic acid
can be added to block Interference from chlorine. Interference from
persanganate, produced by the ozonation of manganese, Is corrected by
running a blank in which ozone Is destroyed prior to addition of the
indigo reagent. The sa les can be analyzed using a spectrophotometer
at a 600 mm wavelength which can detect residuals as low a: 2 u 9 /L or
a visual color comparison method which can measure d i to 10 ugh
ozone. Although currently available monitoring probes do not use the
Indigo Trisulfonate Method, they can be calibrated via this method.
3-16

-------
or an equivalent method as approved by the Primacy Agency with air or
oxygen applied during testing, using the same feed gas and rate as used
during operation. Guidance for the determination of detention time is
included in Appendix C.
A recent survey of operating ozone systems in drinking water
treatment plants in the United States indicated that all 40 plants employ
either bubble diffusers or submerged turbine contactors (Robson et al.
1Q88). It shou%d be noted that this does not preclude the use of other
types of contactors for disinfection.
The sections on ozone providing guidance for determining CT are
currently being developed and 4 therefore, are not included in this draft
manual.
3-17

-------
Surr ar !
Many systems which do not provide filtration will have difficulty
in providing the contact time necessary to satisfy the inactivation
requirements prior to the first customer. For example, a system using
free chlorine at a water temperature of 5 C, a pH of 7.0 and a chlorine
reudual of 1.4 mg/I would require 111 minutes of contact time to meet the
inactivation requirement. Potential options for these systems include:
— Installation of storage facilities to provide the required
contact time under maximum flow conditions.
— Use of an alternate primary disinfectant such as ozone or
chlorine dioxide which has CT values lower than those required
for free chlorine for the required inactivation.
For some systems, the difficulty in obtaining the required
inactivation may only be a seasonal problem. A system that has raw water
temperatures which reach 20 C during the su er months at a pliof 7.0k may
have sufficient contact time to meet the CT of 56 .g/L—.in (Table E.5) at
a chlorine concentration of 1 mgfL. However, assuming the same pH and
chlorine concentration, it may not have sufficient contact time to meet
the CT requirement at 5 C, 149 mg/L-mln (Table E-2), or at 0.5 C,
210 mg/I-mm (Table E-1). Under those conditions, a system could choose
to use ozone or chlorine dioxide on a seasonal basis, since they are
stronger dlslnfectants requiring a shorter contact time.
As indicated in Table E-12, the CT values for chloramines may be
impractical to attain for most systems. Systems which currently utilize
chioramines as a primary disinfectant may need to use either free chlor-
ine, chlorine dioxide or ozone In order to provide the required disin-
fection. However, systems using chioremines as a primary disinfectant may
chose to demonstrate the adequacy of the disinfection. Appendix 6
presents a method for making this demonstration.
Meeting the Inactivation Reoulrement Using Alternate Disfnfectants
For syst using disinfectants othfr than chlorine, chioramines
chlorine dioxide, or ozone, the effectiveness of the disinfectant can be
demonstrated using the protocol contained in Appendix 6. The protocol in
Appendix G.3 for batch testing should be follm ed for any disinfectant
3-18

-------
which can be prepared in an aqueous solution and will be stable throughout
the testing. For disinfectants which are not stable, the pilot study
protocol outlined in Appendix G.4 should be followed.
3.2.2 Determination of Overall Inactivation for Residual Profile,
MultiDle Disinfectants and Multiole Sources
For systems which apply disinfectant(s) at more than one point, or
choose to prbfile the residual from one point of application, the total
inactivation is the sum of the inactivation ratios between each of the
points of disinfection or between each of the residual monitoring points,
respectively. The portion of the system with a measurable contact time
between two points of disinfection application or residual monitoring will
be referred to as a section. The calculated CT (CT , 1 j for each section
is determined daily.
The CT needed to fulfill the disinfection requirements is CT 99 ,
corresponding to a 3-log inactivation of Giardia cysts and greater than
or equal to a 4-log inactivation of viruses (except for chloramines and
sometimes chtorine dioxide as explained in Section 3.2.1). The inactiva-
tion ratio for each section is represented by CTC,IC/CT 99 ,, as explained
in Section 3.2.1, and indicates the portion of the required inactivation
provided by the section. The sum of the inactivation ratios from each
section can be used to determine the overall level of disinfection
provided. Assuming inactivation is a first order reaction, the inac-
tivation ratio corresponds to log and percent inactivations as follows:
£leaIc&Ig9 log Inactivation Percent Inactivation
0.17 • 0.5 log • 68%
0.33 • 1 log 90%
0.50 • 1.5 log • 96.8%
0.67 • 2 log 99%
0.83 • 2.5 log a 99.7%
1.00 a 3 log a 99 .9%
1.33 a 4 log 99.99%
3—19

-------
CT,, Can be determined for each section by referring to Tables E-1
through E—13 in Appendix E 1 using the pH (when chlorine s the disinfec-
tant) and temperatures of the water for the respective sections. These
tables present the log inactivation of Giardia cysts and viruses achieved
by CTs at vanous water temperatures and pHs.
Log iriactivations are additive, so:
0.5 Log + 1.0 Log 1.5 Log or
0.ilCT ,, + 0.33CT ,, a 0.5C1 , , ,
If the sum of the inactivation ratios Is greater than or equal to
ones the required 3-los inactivation of Gfardia cysts has been achieved.
An inactivation ratio of at least 1.0 Is needed to demonstrate compliance
with the Giardia cyst inactivation requirements for unffltered systems.
The total log inactivation can be determined by multiplying the sum
of the inactivation ratios (sum (CTCII /CT,,,))I by three. The total log
Inactivation can be determined In this way because CT,,, is equivalent to
a 3—log inactivation. The total percent inactivation can be determined as
follows:
y • j.QQ. — (quatlon (I)
10’
where: y • % inactivation
x • log inactivation
For example:
x • 3.0 log Inactivation
y — 100 a _____ • 99.9 % inactivation
io
As explained In Section 3.2.t the CTca c determined for each disin-
fection section Is the product of the disinfectant residual In .ç/L and
the detention ti.. in minutes through the section at peak hourly flow.
However, for many water systems peak hourly flow will not necessarily
occur simultaneously In all sections. ‘The extent to which the occurrence
of peak hourly flow will vary between sections of the system depends on
3-20

-------
the characteristics of an individual system including its size, storage
capacity within the distribution system, the number of sources, and
hydraulic capacities between different sections. In order to simplify the
determination of peak hourly flow for the system, it should be taken as
peak hourly flow in the last section of the system prior to the first
customer.
The CT values for all the sections should be calculated for the flow
and the residuals occurring during the hour of peak flow ‘in the last
section. The most accurate way to determine the flow in a particular
section is through the use of a flow meter. Howeveir . some sections of the
system may not have a flow meter. The following guidelines can be used
to determine the flow to be used in calculating CT:
— For sections which do not have meters, the flow should be
assumed to be the higher of the two flows occurring in the
closest upstream and downstream sections with meters.
a In cases where a section contains a pipeline and a basin with
the flow meter located prior to the basin, the metered flow
does not represent the discharge rate of the basin. The
difference in inlet and discharge rates from a basin will
impact the water level in the basin. As explained in Appendix
C, falling water levels will result in lower values.
— To assure that the detention time of a basin is not
overestimated, the discharge flow from a basin should
be used In lieu of the influent flow, unless the
influent flow is higher.
— To estimate the discharge flow from a basin the closest
flow meter downstream of the basin should be used.
The following example presents the determination of the total
percent inactivation for multiple points of disinfection, with variation
in flow between sections.
A coanity of 6,000 people obtains its water supply from a lake
which Is 10 mIles from the city limits. Two 0.2 MG storage tanks are
located along the 12-inch transmission line to the city. The water Is
disinfected with chlorine dioxide at the lt from the lake and with
chlorine at the discharge from the first and second storage tanks. The
3-21

-------
average water demand of the corrn lunity is 1 lCD iwith a peak hourly demand
of approximately 2 1160. For the calculations of the overall percent
inactivation, the supply system is divided into three sections as shown
on Figure 3-6.
Section 1 — from the lake to the discharge from the flrst storage
tank,
Section 2 - from the discharge from the first storage tank to the
discharge from the second tank
Section 3 - from the discharge of the second storage tank to the
first customer
The overall inactivation is computed daily for the peak hourly flow condi-
tions. Sections 1 and 3 contaIn flow meters to monitor the water being
withdrawn from the lake and the water being delivered to the distribution
system as shown on F Igure 3-6. Ott the day of this example calculation,
the peak hourly flow in section 3 was 2 MCD. During this hour, water was
being withdrawn from the lake at a rate of 1.5 mgd. Considering the
placement of flow meters, the flow of 2 mgd measured in section 3 should
be used for calculating CT for that section. SInce section 2 does not
have a flow meter, the meter in section 3 serves as a measure of the
discharge from storage tank 2 and should be the flow used in the
calculation of CT for section 2. The flow meter in section 1 records the
flow through the transmission main which should be used in the calculation
of CT for the pipeline. Howeyer, this meter does not represent the
discharge from storage tank 1. Since the water is being pumped to the
distribution system at a higher rate than the flow entering storage tank
1, the flow of 2 mgd measured in section 3 should be used for calculating
the CT for storage tank 1.
The pH temperature and disinfectant residual of the water were
weasured at the end of each section just prior to the next point of
disinfection and the tint customer during the hour of peak flow. The
water travels through the 12-inch transaisslom main at 177 ft/m m at
3-22

-------
tat CU3’TOMI
FiGURE 3.6 DETERMINATION OF INACTIVATION FOR
MULTIPLE DISiNFECTANT APPLICATiON
TO A SURFACE WATER SOURCE
CHLORINE CHLORINE
DIOXIDE
SECTION
I
SECTION
2

-------
1.5 MCD.’ The detention times of the storage tanks were read off the
vs. Q plots generated from tracer studies conducted on the storage tanks
(see Appendix C). The data for the inactivation calculation are as
follows:
Section 1 Section 2 ectipn 3
length of pipe (ft) 15840 26 400 10 560
flow (ingd)
pipe 1.5 2.0 2.0
tank 2.0 2.0
contact time ( Mn)
pipe 89 1 11 45
tank 216 114 0
tota ’ 205 225 45
disinfectant chlorine chlorine chlorine
dioxide
residual (mgft) 0.1 0.2 0.4
temperature (C) 5 5 5
p H 8 8
This information is then used in conjunction with the C 1 9 g values in
Appendix E to determine the (CTCI,CICTI; ) in each section as follows:
Sect ion 1 — Chlorine dioxide
- 0.1 !ngfL x 105 minutes • 20.5 mg/I-m m
From Table E-8 at a temperature of S C and pH a 8
CT 9 99 is 26 mg/ I-mm
CT , /CT 19 , — 20.5 mq/L-rnin • 0.79
26 mg/I-sin
Section 2 • Chlorine
0.2 mg/L x 225 minutes a 45 mg/L-mln
From Table E-2 at a te erature of 5 C and pH • 8,
CT 99 g Is 198 mg/I-sIn
• 45 mg/ I-a iim a 0.23
198 mg/L—miri
• Q • 1.5 X 29’ cal/day X 1 ttL X dav _ • 171 ft/sin
A ( 1 ft fl’/4 ) 7.48 gal 1440 pin
3-23

-------
Section 3 — Chlorine
0.4 mg/L—min x 45 mm = 18 nlg/L-mmn
From Table E-2 at a temperature of 5 C and p11 = 8,
CT 99 is 198 mg/L-min
CT /CT 99 18 mg/L-min 0.09
198 mg/L-min
The sum of CTCaIC/CTS 9 is equal to 1.11, which is greater than 1,
therefore, the system meets the requirements of providing a 3-log
inactivation of Giardia cysts. The log inactivation provided is:
x=3x 3x1.11=3.33
a
The percent inactivation can be detennined using equation 1.
y 100 - 1Q 100 - jQQ 100 - 0.05 99.95% inactivation
10 “ 2,138
The system meets the requirement of providing a 99.9 percent inactivation
of Giardip cysts.
The SWTR also requires that the public be provided with protection
from Legionella as well as Giardia cysts and viruses. Inactivation levels
have not been set for Legionella because the required inactivation of
Giardia cysts will provide protection from Legionella. ’ However, this
level of disinfection cannot assure that all Legionella will be Inacti-
vated and that no recontamination or regrowth in recirculating hot water
Kuchta et al. (1983) reported a maximum CT requirement of 225 for a
99 percent inactivation of Leglonella in a 21 C tap water at a pH of
7.6-8.0 when using free chlorine. Using first order kinetics, a 99.9
percent Inactivatton requires a CT of 33.8. Table A-S presents the CTs
needed for free chlorine to achieve a 99.9 percent Inactivation of
Giardia cysts at 20 C. This table indicates that the CT required for
a 3-log inactivation of Giardia at the temperature and pH of the
Legionella test ranges from 67 to 108 depending on chlorine residual.
These CT’s are two to three times higher than that which is needed to
achieve a 3 log inactivation of Legionella .
3-24

-------
systems of buildings or cooling systems will occur. Appendix 8 provides
guidance for monitoring and treatment to control Legionellp in institu-
tional systems.
The above discussion pertains to a system with one source with
sequential disinfection. Another system may blend more than one source,
and disinfect one or more of the sources independently prior to blending.
System conditions which may exist include:
- All the sources are combined at one point prior to supplying
the colm unity but one or more of the sources are disinfected
prior to being combined, as shown on Figure 3-7.
- Each source is disinfected individually and enters the
distribution system at a different point, as shown on
Figure 3-8.
For all systems combining sources, the first step in determining the
CT should be to determine the CT 11 provided from the point of blending
closest to the first customer using the contact time and residual at peak
hourly flow for that portion of the distribution system. This corresponds
to section D on Figure 3-7 and section £ on Figure 3-8. If the CT 11 for
section D or E provides the required inactivation, no additional CT credit
is needed and no further evaluation is required. However, if the CT for
section D or E is not sufficient to achieve the required Inactivation,
then the inactivation ratio (CTCI, )/(CTft ) should be determined for each
section to determine the overall inactivation provided for each source.
The total Inactivation must be greater than or equal to one for all
sources In order to comply with the requirements for 3-log inactivation
of Gi rdia cysts.
On Figure 3-7, sections A, B, C and D contain sampling points a, b,
c and d, respectively. The sum of the Inactivation ratios for sections
A+D, 8+0 and C+D must each be greater than or equal to one for the
disinfection requirements to be met.
The total Inactivation for each source on Figure 3-7 should be
determined as follows:
Source I
— Determine CT for sections A and 0 based on the residual
measurements”at sample points a and d. and the travel tune
3-25

-------
lit CUSTOMER
• COMSINATION POINT
FIGURE 3-8 MULTIPLE COMBINATION POINt
FOR INDIVIDUALLY D 1SINFECTEL
SURFACE SOURCES
a
C
d
FIGURE 3-7 INDIVIDUALLY DISINFECTED
SURFACE SOURCES COMBINED
AT A SINGLE POINT
a
d
a
let CUSTOMER
S — s
APPLICATION
SAMPLINS POINTS

-------
through each section under peak hourly flow Conditions for the
respective section.
- Determine C T 99 for the pH and temperature conditions in each
section using he tables in Appendix E
- Calculate the inactivation ratios (CT /CT, 9 9) for sections
A and D.
- Calculate the sum of the inactivation ratios for sections A
and D to determine the total inactivation for source I.
- If the sum of the inactivation ratios is greater than or equal
to 1.0, the system has provided the required 3-log Giarda
cyst inactivation.
Source II
- Determine CT for section B based on the residual measured
at sample point b and the travel time through the section
under peak hourly flow conditions.
— Determine CT 99 for section B for the pH and temperature
conditions in he Section using the appropriate tables in
Appendix E.
— Calculate the inactivation ratio (CT , 1 /CT 99 ) for section B.
• Add the inactivation ratios for sections B and C to determine
the total inactivation for source II.
- If the sum of the inactivation ratios is greater than or equal
to 1.0, the system has provided the required 3-log Giardia
cyst inactivation for the source.
Source III
- Determine CT for section C based on the residual measured
at sample p nt c and the travel time through the section
under peak hourly flow conditions.
— Determine CT 9 , for section C for the pH and temperature
conditions In he section using the appropriate tables in
Appendix E.
— Calculate the Inactivation ratio (CT . 1 /CT ,) for section C.
— Add the Inactivation ratios for sections C and 0 to determine
the total inactivation for Source III.
3—26

-------
- If the sum of the inactivation ratios is greater than or equal
to 1.0, the system has provided the required 3-log Giardia
cyst inactivation for the source.
The determination of the total inactivation for each source may
require more calculations for systems such as that on Figure 3-8 than on
Figure 3-7. On Figure 3—8 sections A, B, C, D, and E contain sampling
points a, b c, d, and e respectively. In order to minimize the
calculations needed, the determination of the total inactivation should
begin with the source closest to the first customer.
The total inactivation for each source or. Figure 3-8 should be
determined as follows:
Source III
- Determine CT for sections C and E based on the residual
measurement sample points c and e and the defe,rtion time
in each section under peak hourly flow conditions for the
respective section.
- Determine CT 99 for the pH and temperature conditions in each
section using %he tables in Appendix E.
- Calculate the inactivation ratios (CTC,IC/CT 99 ) for sections
C and E.
- Calculate the sum of the inactivation ratios for sections C
and E to determine the total inactivation for source III.
- If the sum of the Inactivation ratios is greater than or equal
to 1.0, the system has provided the required 3-log Giardia
cyst inactivation for source III.
Source II
- Determine CT for section D based on the residual measured
at sample po t d and the detention time through the section
under peak hourly flow conditions.
- Determine CT 9 , for section D for the pH and temperature
conditions In he,section using the appropriate tables in
Appendix C.
- Calculate the inactivation ratio (CTC.IC/CT,,,) for section D.
- Add the inactivation ratios for sections D and E to determine
the overall Inactivation.
3-27

-------
— If the sum of the inactivation ratios is greater than or equal
to 1.0, the system has provided the required 3-log Giardia
cyst inactivation for source 11, as well as source I since the
water from each of these sources are combined prior to
sections D and E.
— If the total inactivation ratio for sections 0 and E is less
than 1.0, additional calculations are needed. Proceed as
follows for source II.
- Determine CT for section 8 based on the residual measured
at sample poi i b and the detention time through the Section
under peak hourly flow conditions.
- Determine CT 99 for section 8 for the pH and temperature
conditions in 9 the section using the appropriate tables in
Appendix E.
- Calculate the inactivation ratio (CT /CT, 9 9) for section 8.
- Add the inactivation ratios for sections 8, D and E to
determine the total Inactivation for source II.
— If the sum of the inactivation ratios is greater than or equal
to 1.0, the system has provided the required 3-log Glardia
cyst inactivation for the source.
Source I
As noted in the determination of the inactivation provided for
source II, if the sum of the inactivation ratios for sections 0 and E is
greater than or equal to 1.0, the system has provided the required 3-log
Giardia cyst Inactivation. However, if this sum is less than 1.0
additional calculations will be needed to determine the overall inactiva-
tion provided for source 1. The calculations are as follows:
Source I
• Determine CT for section A based on the residual measured
at sample po a and the detention time In the section under
peak hourly flow conditions.
• Determine CT for section A for the pH and temperature
conditions the section using the appropriate tables in
Appendix E.
— Calculate the Inactivation ratio (CTCIIC/CT, 99 ) for section A.
3-28

-------
— Add the inactivation ratios for sections A, D, and E to
determine the total inactivation for source I.
— If the sum of the inactivation ratios is greater than or equal
to 1.0, the system has provided the required 3-log Giardia
cyst inactivation for the source.
3.2.3 Demonstration of Maintaining a Res duai
The SWTR establishes two requirements concerning the maintenance of
a residual. The first requirement is to maintain a minimum residual of
0.2 nig/L entering the distribution system. The second is to maintain a
detectable residual throughout the distribution system. The disinfectant
used to meet these requirements is identified as the secondary disinfec-
tant throughout the remainder of this document. These requirements are
further explained in the following sections.
Maintaining a Residual Entering the Distribution System
To avoid filtration, the disinfectant residual in water entering the
distribution system cannot be less than 0.2 mg/i for more than four hours,
with one exception noted below. Systems serving more than 3,300 persons
must monitor continuously. If there Is a failure in the continuous
monitoring equipment, the system may substitute grab sampling every four
hours for up to five working days following the failure of the equipment.
Systems serving 3,300 or fewer people may monitor continuously or take
grab samples at the frequencies prescribed below:
System Size by Pooulatfon Samo1es/day*
500 1
501-1,000 2
1,001-2,500 3
2,501—3,300 4
*S mp1es cannot be taken at the same time.
The sa 11ng intervals are subject to Primacy Agency review and
approval.
If at any time the residual disinfectant concentration falls below 0.2
mg/i In a system using grab sample monitoring, the system must continue
to take a grab sample every four hours until the residual disinfectant
concentration Is equal to or greater than 0.2 mg/l. For all systems, if
3-29

-------
the residual concentration is not restored to at least 0.2 mg/i within
four hours after a value of less than 0.2 mg/i is observed, the system is
in violation of a treatment technique requirement, and must install
filtration. However, if the Primacy Agency finds that the exceedance was
caused by an unusual and unpredictable circumstance, the Primacy Agency
may choose not to require filtration. EPA expects Primacy Agencies to use
this provision sparingly; it is intended to encompass catastrophic events,
not infrequent large storm events. In addition, any time the residual
concentration falls below 0.2 mg/i, the system must notify the Primacy
Agency. Notification must occur as soon as possible, but no later than
the end of the next business day. The system also must notify the Primacy
Agency by the end of the next business day whether or not the residual was
restored within four hours.
Failure of a monitoring or reporting requirement does not trigger
a requirement to filter although they are violations.
Maintaining a Residual Within the System
To avoid filtration, the disinfectant residual in the distribution
system cannot be undetectable in more than five percent of the samples in
a month, for any two consecutive months that the system serves water to
the public. Systems may measure HPC instead of disinfectant residual.
Sites with HPC concentrations of less than or equal to 500/mi are
considered equivalent to sites with detectable residuals for the purpose
of determining compliance. Public water systems must monitor for the
presence of a disinfectant residual (or HPC levels) at the same frequency
and locations as total coliform measurements taken pursuant to the Total
Coliform Rule. However, if the Primacy Agency determines, based an site-
specific considerations, that a system has no means for having a sample
transported and analyzed for HPC by a certified laboratory within the
requisite time and temperature conditions (Method 907, APHA, 1985), but
that the system Is pro 1d1ng adequate disinfection in the distribution
system this requirements does not apply to that system.
For systems t1ch use both surface and ground water sources, the
Primacy Agency may allow the system to take disinfectant residual or HPC
samples at points other than the total coliform sampling locations if it
3-30

-------
determines that such points are more representative of treated (disin-
fected) water quality within the distribution system.
Disinfectant residual can be measured as total chlorine, free
chlorine, combined chlorine or chlorine dioxide (or HPC level). The SWTR
lists the approved analytical methods for these analyses. For example,
several test methods can be used to test for chlorine residual in the
water, including amperometric titration, GPO colorimetric, OPD ferrous
titrimetric method and iodoiuetric method, as described In the 16th Edition
of Standard Methods. 9 Appendix 0 provides a review and sunrnary of
available techniques to measure disinfectant residuals.
If a system fails to maintain a detectable disinfectant residual or
an HPC level of less than or equal to 500/mi in more than 5 percent of the
samples during a month, for any two consecutive months the system serves
water to the public, the system is In violation of a treatment technique
requirement. In addition, this system must install filtration unless the
Primacy Agency determines that the violation was not due to a deficiency
in treatment of the source water (e.g., the violation was due to a
deficiency in the distribution system, such as cross-connection contamina-
tion or failure in the pipeline).
The absence of a detectable disinfectant residual in the distribu-
tion system may be due to a number of factors, including:
- Insufficient chlorine applied at the treatment plant
- Interruption of chlorination
- A change in chlorine demand in either the source water or the
distribution system
- Long standing times and/or, long transmission distances
$ Also, portable test kits are available which can be used In the field
to detect residual upon the approval of the Primacy Agency. These kits
may employ titration or colorimetric test methods. The colorimetric
kits einpioy either a visual detection of a residual through the use of
a color wheel, or the detection of the residual through the use of a
hand held spectrophotometer.
3.31

-------
Available options to correct the problem of low disinfectant
residuals in distribution Systems include:
— Routine flushing
- Increasing disinfectant doses at the plant
- Cleaning of the pipes (either mechanically by pigging or by
the addition of chemicals to dissolve the deposits) in the
distribution system to remove accumulated debris which may be
exerting a disinfectant demand;
— Flushing and disinfection of the portions of the distribution
system in which a residual is not maintained; or
- Installation of satellite disinfection feed facilities within
the distribution system.
For systems unable to maintain a residual, the Primacy Agency may
determine that it is not feasible for the system to monitor IIPC and judge
that disinfection is adequate based on site-specific conditions.
Additional information on maintaining a residual in the system is
available in the AWWA Manual of Water Supply Practices and Water
Chlorination Principles and Practices.
3.2.4 Disinfection System Redundancy
Another requirement for unfiltered water supply systems is
disinfection facility redundancy. A system providing disinfection as the
only treatment is required to assure that the water delivered to the
distribution system is continuously disinfected. The SWTR requires either
redundant disinfection equipment with auxiliary power and automatic
start-up and alarm; or an automatic shutoff of delivery of water to the
distribution system when the disinfectant residual level drops below 0.2
mg/L. In order to fulfill the requirement of providing redundant
disinfection facilities, the following system is recommended:
All components have backup units with capacities equal to or
greater than the largest unit on-line.
— A minimum of two storage units of disinfectant which can be
used alternately - e.g., two cylinders of chlorine gas, two
tanks of hypochlorite solution
3-32

-------
Where the disinfectant is generated on-site, such as ozone,
backup units with a capacity equal to or greater than that of
the largest unit on-line.
- Automatic switchover equipment to change the feed from one
storage unit to the other before the first empties or becomes
inoperable
- Feed systems with backup units with capacities equal to or
greater than the largest unit on-line.
- An alternate power supply such as a standby generator with the
capability of running all the electrical equipment at the
disinfection station. The generator should be on-site arid
functional with the capability of automatic start-up on power
failure
Systems providing disinfection may have several different configura-
tions for type and location of disinfectant application. The føllowing
guidelines are provided to assist Primacy Agencies and utilities in
deteriiiining the need for redundancy. Possible disinfection configurations
include:
— one disinfectant used for primary and secondary disinfection
- one point of application
- multiple points of application
- two different disinfectants used for primary and secondary
disinfection
In many cases one disinfectant will be used to fulfill both the
total inactivation and residual requirements. One or more application
points may be used to accomplish this. When one application point is used
to meet both the primary and secondary disinfection requirements, the
system Is required to Include redundant disinfection facilities.
When multiple points of application are used, redundancy is
recomeended for the disinfection facilities at each point of application
which is essential to meet the total Inactivation requirements. In
addition, to assure the maintenance of a residual entering and throughout
the distribution system, either:
— the last point of application prior to the distribution system
should have redundancy, or
3-33

-------
- the point of application innediately prior to this point
should have redundancy and sufficient capacity to assure a
residual entering the distribution system.
Systems may also use two different disinfectants, one to fulfill the
inactivat•ion requirements and the second to maintain a residual. An
example of this would include a system using ozone as a primary disinfec-
tant and chioramines as a secondary disinfectant. EPA reconmiends that:
— the disinfection facilities at each point of disinfectant
application in the primary system essential in providing the
overall inactivation requirements include redundancy, and
— the secondary disinfection facilities include redundancy,
unless the disinfectant used for primary disinfection can
provide a residual for the distribution system as well, If
the primary disinfectant can be used for residual maintenance 1
the last point of primary disinfectant application should
include redundancy and sufficient capacity to assure a
residual entering the distribution system.
Appendix 1 contains more specific information to assist the Primacy
Agency in establishing requirements for providing redundant disinfection
facilities,
Providing automatic shutoff of water delivery requires approval by
the Primacy Agency. The Primacy Agency must determine that this action
will not result in an unreasonable risk to health or interfere with fire
protection. This determination should include the evaluation of the
system configuration to protect against ne9ative pressures in the system,
and providing for high demand periods including fire flow requirements.
Automatic shutoff should be allowed only if systems have adequate
distribution system storage to maintain positive pressure for continued
water use.
3 1 34

-------
3.3 SITE-SPECIFIC CONDITIOUS
In addition to meeting source water quality criteria and disinfec-
tion criteria, nonfiltering systems using surface water supplies must meet
the following criteria:
- Maintain a watershed control pro 9 rarn
- Conduct a yearly on-site inspection
- Determine that no waterborne disease outbreaks have occurred
- Comply with the revised annual total coliform MCL
- Comply with TTHM regulations (currently applies to systems
serving >10,000 people)
Guidelines for meeting these other criteria are presented in the follow-
ing sections.
3.3.1 Watershed Control Program
A watershed control program is a surveillance and monitoring program
which is conducted to protect the quality of a surface water source. An
aggressive and detailed watershed control program Is desirable to
effectively limit or eliminate potential contamination by human viruses.
A watershed program may impact parameters such as turbidity, certain
organic compounds, viruses, total and fecal coliforms, and areas of wild-
life habitation. However, the program is expected to have little or no
impact on parameters such as naturally occurring inorganic chemicals.
Limiting human activity in the watershed may reduce the likelihood of
animals becoming infected with pathogens and thereby reduce the transmis-
sion of pathogens by wildlife. Preventing animal activity near the source
water intake prior to disinfection may also reduce the likelihood of
pathogen occurrence at the intake.
The effect of a watershed program Is difficult to quantify since
many variables that Influence water quality are beyond the control or
knowledg. of the water supplier. As a result, the benefit of a watershed
control program or specific control measures must in many cases be based
on accumulated cause and effect data and on the general knowledge of the
Impact of control measures rather than on actual quantification. The
effectiveness of a program to limit or eliminate potential contamination
by human viruses will be determined based on: the comprehensiveness of
the watershed review; the ability of the water system to effectively carry
3-35

-------
ALl Public Waler
Systems
______________________________________________________ ___________________________ I _______________________
C .CL’S Surrac j ( cer,tirv Source Type
Sc rces I
Lai es ceservc rs
T Scurce s
S rea s Cree __________ __________
ver$ e::
__________ _________ Scurce is Scring
Infiitraticn Ga Ieri cr _________________
Rannev WeI
____________________ Weii s rote:ie rom I
_ BzsdonI:t.t,
Oir.c* Suifsc. l,tfluiics 1
I
Review System ‘ e
anc Coriøuc
Sanuary Survey
I
SWTR Apphes ( ) Surface Water
_____ I Source nhIuenced by
Un ec ed•
Concuct Pani j1a e
Aria ysis. Monnor
Changes r. Waier
Quabty. Terr .raxure.
etc.
I
Summary of Finø ngs
(} Indcate Source is
Influenced by Surface
Watec and Could
Contain G,a, ia’
FIGURE 2-1 STEPS TO SOURCE CLASSiFICATION

-------
out and monitor the management decisions regarding control of detrimental
activities occurring in the watershed; and the potential for the water
system to maximize land ownership and/or control of land use within the
watershed. According to the SWIR, a watershed control program should
include as a minimun :
— A description of the watershed including its hydrology and
land ownership
— Identification, monitoring and control of watershed character-
istics and activities in the watershed which may have an
adverse effect on the source water quality
- A program to gain ownership or control of the land within the
watershed through written agreei ents with land owners, for the
purpose of controlling activities which will adversely affect
the microbiological qual ty of the water
— An annual report which identifies special concerns In the
watershed and how they are being handled, identifies
activities in the watershed, projects adverse activities
expected to occur in the future and how the utility expects
to address them.
Appendix J contains a more detailed guide to a comprehensive
watershed program.
In preparing a watershed control program, surface water systems
should draw upon the State watershed assessments and nonpoint source (NPS)
pollution management programs required by S319 of the Clean Water Act.
Information on these programs is available from State water quality
agencies or EPA ’s regional offices. Assessments identify NPS pollutants
in water and assess the water quality. Utilities should use the
assessments when evaluating pollutants in their watershed. Surface water
quality assessments can also be obtained from the lists of waters prepared
under S304(l) of the Clean Water Act, and State biennially prepared
S305(b) reports.
State NPS management programs Identify best management practices
(BliPs) to be employed in reducing NPS pollution. These management
programs can be incorporated in the watershed program to protect against
degradation of the source water quality.
3-36

-------
For systems using ground water sources under the influence of
surface water, the control measures delineated in the Wellhead Protection
(WHP) program encompass the requirements of the watershed control program,
and can be used to fulfill the requirements of the watershed control
program. Guidance on the content of State Weithead Protection Programs
and the delineation of welihead protection areas is given in: “Guidance
for Applicants for State Welltiead Protection Program Assistance Funds
Under the Safe Drinking Water Act, TM June, 1g87, and “Guidelines for
Delineation of Wellhead Protection Areas,” June, 1987, available from the
EPA office of Ground-Water Protection (WH.550G).
As a minimum, the WHP program must:
- Specify the duties of State agencies, local governmental
entities and public water supply systems with respect to the
development and implementation of Programs;
- Detennine the welIhead protection area (WKPA) for each
welihead as defined in subsection 1428(e) based on all
reasonably available hydrogeologic information, ground-water
flow, recharge and discharge and other information the State
deems necessary to adequately determine the WHPA;
- Identify within each WHPA all potential anthropogenic sources
of contaminants which may have any adverse effect on the
health of persons;
- Describe a program that contains, as appropriate, technical
assistance, financial assistance 1 implementation of control
measures, education, training and demonstration projects to
protect the water supply within W14PAs from such contaminants;
- Present contingency plans for locating and providing alternate
drinking water supplies for each public water system in the
event of well or weilfield contamination by such contaminants;
— Consider all potential sources of such contaminants within the
expected welihead area of a new water well which serves a
public water supply system; and
— Provide for public participation.
3.3.2 On-site Insoection
The watershed control program and on-site inspection are inter-
related preventive strategies. On-site Inspection Is actually a program
3-37

-------
which includes and surpasses the requirements of a watershed program.
While the watershed program is mainly concerned with the water source,
on-site inspection includes some additional requirements for source water
quality control arid is also concerned with the disinfection facilities.
As defined by the EPA, an on-site inspection includes review of the water
source, disinfection facilities and operation and maintenance of a pubhc
water system for the purpose of evaluating the adequacy of such systems
for producing safe drinking water.
The SWTR requires an annual on-site inspection to evaluate the
watershed control program and disinfection facilities. The inspection
must be performed by a party approved by the Primacy Agency. The inspec-
tion should be conducted by competent individuals such as sanitary and
civil engineers, sanitarians, and technicians who have experience and
knowledge in the operation 4 maintenance, and design of water systems, and
who have a sound understanding of public health principles and waterborne
diseases. Guidance for the contents of an inspection are included in the
following paragraphs. Appendix K presents guidelines for a sanitary
survey which includes and surpasses the requirements of an on-site
inspection.
As the first step in determining which SWIR requirements, if any.
a source is subject to, EPA reconvuends that utilities conduct a detailed,
comprehensive sanitary survey. Appendix K presents a comprehensive list
of water system features that the person conducting the survey should be
aware of and review as appropriate. This initial investigation estab-
lishes the quality of the water source, its treatment and delivery to the
consumer. EPA recoanends that this comprehensive evaluation be repeated
every three years for systems serving 4,100 people or less and every five
years for systems serving more than 4,100 people. Also, under the Total
Colitorm Rule, ground water systems which take less than 5 colifonn
samples per month must conduct such sanitary surveys within every 5 or 10
years depending upon whether the source Is protected and disinfected.
The annual on-site tnspectIon to fulfill the SWIR requirements
should Include as a minimum:
3-38

-------
1. Source Evaluation
a. Review the effectiveness of the watershed control
program (Appendix J).
b. Review the physical condition and protection of the
source intake.
c. Review the maintenance program to insure that all
disinfection equipment is appropriate and has received
regular maintenance and repair to assure a high
operating reliability.
2. Treatment Evaluation
a. Review improvements and/or additions made to disinfec-
tion processes during the previous year to correct
deficiencies detected in earlier surveys.
b. Review the condition of disinfection equipment.
c. Review operating procedures.
d. Review data records to assure that all required tests
are being conducted and recorded and disinfection is
effectively practiced (CT calculations should be spot
checked to ensure that they were done correctly).
e. Identify any needed improvements in the equipment,
system maintenance and operation, or data collection.
In addition to these requirements, a periodic sanitary survey is
recomended for all systems, including those with filtered and unfiltered
supplies. The sanitary survey should include the items listed In 1 and
2 above as well as:
3. Distribution System Evaluation
a. Review the condition of storage facilities.
b. Determine that the system has sufficient pressure
throughout the year.
c. Verify that system equipment has received regular
sal ntenance.
d. Review additions/improvements incorporated during the
year to correct deficiencies detected in the initial
inspection.
3-39

-------
e. Review cross connection prevention program, including
annual testing of backflow prevention devices.
f. Review routine flushing program for effectiveness.
g. Evaluate the corrosion control program and its impact
on distribution water quality.
h. Review the adequacy of the program for periodic storage
reservoir flushing.
i. Review practices in repairing water niain breaks to
assure they include disinfection.
4. Management/Operation Evaluation
a. Review the operations to assure that any difficulties
experienced during the year have been adequately
addressed.
b. Review staffing to assure adequate numbers of properly
trained andfor certified personnel are available.
c. Verify that a regular maintenance schedule is followed.
d. Audit systems records to verify that they are adequately
maintained.
e. Review bacteriological data from the distribution system
for coliform occurrence, repeat samples and action
response.
3.3.3 No Disease Outbreaks
Under the provisions of the SWTR, a surface water system which does
not filter must not have been identified as a source of waterborne
disease, or if It has been so identified, the system must have been
modified sufficiently to prevent another such occurrence, as determined
by the Primacy Agency. If a waterborne disease outbreak has occurred and
the outbreak was or is attributed to a treatment deficiency, then the
system ist install filtration unless the system has upgraded its
treatment system to remedy the deficiency which led to the outbreak and
the Primacy Agency has determined that the system is satisfying this
requirement. If the Primacy Agency has determined the disease outbreak
was the result of a distribution system problem rather than a source
3.40

-------
water treatment deficiency, the system is not required to install
filtration.
In order to determine whether the above requirement is being met,
the responsible federal, state and local health agencies should be
surveyed to obtain the current and historical information on waterborne
disease outbreaks which may have occurred within a given system. Whether
conducted by the Primacy Agency or submitted by the water purveyor, this
information should include:
1. Source of the Information:
a. Name of agency
b. Name and phone number of person contacted
c. Date of inquiry
2. Outbreak Data
a. known or suspected Incidents of waterborne disease
outbreaks
b. Date(s) r,f occurrence(s)
c. Type or identity of Illness
d. Number of cases
3. Status of Disease Reporting:
a. Changes in regulations; e.g., giardiasis was not a
reportable disease until 1985
4. If a Disease Outbreak has Occurred:
a. Was the reason for the outbreak identified; e.g.,
inadequate disinfection?
b. Did the outbreak occur while the system was In Its
current configuration?
c. Was remedial action taken?
d. Have there been any further outbreaks since the remedial
action was taken?
If a review 0 f the available information Indicates that the system
or network for disease reporting Is inadequate within the Primacy Agency s
area of responsibility, efforts should be made to encourage the appropri-
3-41

-------
ate agencies to upgrade the disease reporting capabilities within the
area.
3.3.4 Monthly Coliform MCI
To avoid filtration, a system must comply with the MCI for total
coliforins,. established in the Total Coliforin Rules for at least 11 out of
the previous 12 months the system served water to the public on an ongoing
basis, unless the Primacy Agency determines that failure to meet this
requirement was not caused by a deficiency in treatment of the source
water. if the Primacy Agency makes such a determination, the system is
not required to install filtration. The Total Coliform Rule requires
systems using surface water or ground water under the influence of surface
water which do not filter to collect a sample at or near the first
customer each day that the turbidity level exceeds 1 NTU within 24 hours
of learning of the result and to analyze the sample for the presence of
total coliforms. (If the Primacy Agency determines that it is not
possible for the system to have such a sample analyzed within 24 hours,
this time limit may be extended on a case-by-case basis.) This sample may
be used to fulfill the routine compliance monitoring requirements of the
Total Coliform Rule. The results of the additional sample must be
included in determining whether the system is in compliance with the
monthly MCI for total colifonns.
3.3.5 Total Trihaloniethane (TTHM) Regulations
For the system to continue to use disinfection as the only
treatment, it must comply with the total trihalomethane (TTHM) MCI
regulation. The current regulation established an MCI for total huM of
0.10 mg/I for systems serving a population greater than 10,000. Both the
MCI and the system population covered may be reduced in the future: and
this should be considered when planning disinfectant application.
One alternative to meet the CT requirements of the SWTR is to
increase the disinfectant dose. For many systems a higher chlorine dose
will result in Increased formation of TTHMS. Changes in disinfection
practice should maintain TTHN levels of less than 0.10 mg/L. in lieu of
increasing chlorine dose, use of an alternate disinfectant which produces
3-42

-------
fewer TTHMs could be considered. Alternate disinfectants include the use
of ozone or chlorine dioxide as primary disinfectants with chlorine or
chioramines as secondary (residual) disinfectants. It is important to
note that EPA also will promulgate regulations for disinfectants and
disinfection by-products which may limit application of some of these
disinfectants. EPA recomends that Primacy Agencies keep informed through
conrunication with EPA on interim guidance on how to avoid conflict for
systems to comply with both the SWIR and the forthcoming regulations on
disinfectants and disinfection by-products. Any changes which appear to
not meet the by-product regulations should not be Implemented.
3-43

-------
4. DESIGN AND OPERATING CRITERIA FOR
FILTRAT ION AND DISINFECTION TECHNOLOGY
4.1 Introduction
To comply with the SWTR, public water systems must include filtra-
tion, or some other approved particulate removal technology, in their
treatment process unless they are able to satisfy certain conditions.
Those conditions include compliance with source water quality criteria and
site-specific criteria. Guidance for determining whether these conditions
are met is provided in Section 3 of this manual. Systems unable to
satisfy these conditiocts must prGvidt particulate removal and meet
criteria pertaining to operation, design and performance. These criteria
are specified in part in the definitions of technologies in the SWTR and
more specifically as determined by the Primacy Agency.
This section provides guidance both for those water systems which
currently do not have filtration equipment and must add it, and for
systems which have existing filtration processes. Guidance on additional
alternatives for small systems is presented in Appendix 1.
This section includes guidance on the following topics:
a. Filtration Technology: Descriptions, capabilities, design
criteria and operating requirements for each technology, and
a listing of major factors to be considered in their
selection, including raw water quality considerations.
b. Disinfection: Descriptions of the most applicable disin-
fection technologies used with filtration systems, and a
presentation of the relative effectiveness of these disinfec-
tion technologies with respect to Inactivation of bacteria,
cysts and viruses.
c. Alternate Technologies: Descriptions of some currently
available alternate filtration technologies.
d. Other Alternatives: Includes a description of some nontreat-
ment alternatives including regionalization and use of an
alternate source.
4.2 Selection of Aooroorlate Filtration Technology
Filtration is generally provided by passing water through a bed of
sand, a layer of diatomaceous earth or a combination bed of coarse anthra—
4-1

-------
cite coal overlaying finer sand. Filters are classified and named in a
number of ways. For example based on application rate, sand filters can
be classified as either slow or rapid; yet these two types of filters
differ in many more characteristics than just application rate. They
differ in their removal process, bed material, method of cleaning, and
operation. Based on the type of bed material, filters can be classified
as sand, diatomaceous earth, dual-media (coal-sand) or even multi-media
in which a third layer of high density sand is used.
4.2.1 General Descriotions
Current technologies specified by the SWTR are:
a. Conventional Treatment: A series of processes including
coagulation, flocculation, sedimentation and filtration.
b. Direct Filtration: A series of processes Including coagula-
tion (and perhaps flocculation) and filtration, but excluding
sedimentation.
c. Slow Sand Filtration: A process which involves passage of raw
water through a bed of sand at low velocity, 9 enerally less
than 0.4 meters/hour (1.2 ft/hr), resulting in substantial
particulate removal by physical and biological mechanisms.
d. Diatomaceous Earth Filtration: A process that meets the
following conditions:
- A precoat cake of diatomaceous earth filter media is
deposited on a support membrane (septum)
— The water Is filtered by passing it through the cake on
the septum; additional filter media, known as body feed,
is continuously added to the feed water In order to
maintain the peneability of the filter cake.
4-2

-------
e. Alternate Technologies: Any filtration process other than
those listed above. Available alternate filtration technolo-
g es include, but are not limited to:
— Package Plants 1
- Cartridge Filters
4.2.2 Capabilities
Filtration processes provide various levels of turbidity and
microbial contaminant removal. When properly designed and operated and
when treating source waters of suitable quality, the above filtration
processes are capable of achieving at least a 2-log (99 percent) removal
of Giardia cysts and at least a 1-log (90 percent) removal of viruses
without disinfection (Logsdon, 1987b; USEPA, 1988b; Roebeck, 1962). The
exception is cartridge filters which may not provide effective virus
removal. A sunnary of the removal capabilities of the various filtration
processes is presented in Table 4-1.
As indicated in Table 4-1, conventional treatment without disinfec-
tion is capable of achieving up to a 3-log removal of Giardia cysts and
up to a 3-log removal of viruses. Direct filtration can achieve up to a
3-log removal of Giardia cysts and up to a 2-log removal of viruses.
Achieving the maximum removal efficiencies with these treatment processes
requires the raw water to be properly coagulated and filtered. Factors
which can adversely affecy removal efficiencies include;
— Raw water turbidities less than I NTU
Cold water conditions
— Non-optimal or no coagulation
— Improper filter operation including:
Depending upon the type of treatment units in place, historical
performance and/or pilot plant work, these plants could be categorized
as one of the technologies in a-d above at the discretion of the State.
Several studies have already Indicated that some package plants
effectively remove Glardla cysts. If such plants provided adequate
disinfection so that the complete treatment train achieves at least a
3—log removal/inactivation of Giardia cysts and a 4-log removal/Inacti-
vation of viruses, use of this technology would satisfy the minimum
treatment requirements.
4-3

-------
TABLE 4- 1
RE! VM. CAPABI l iT IES OF F ILTRATIOti P OCESSES ’
Log Removals
Grdia 2 Tota1 2
______ Cysts Viruses Cplifprm
Conventional Treattne t 3 — >4
Direct Filtration 2 - 3 1 - 2 1 - 3
Slow Sand Filtration 2 — 3 ( 5 ) — 3 w 1 — 2
Diatomaceous Earth
Filtration 2 — 3 ( 5 ) 1 — I — 3
Note:
1. Without disinfection.
2. Logsdon, 1987b.
3. Roebeck ji. 1962.
4. Poynter and Slade 1 1977.
5. These technologies generally achieve greater than a 3-log removal.

-------
TABLE 4-2
GENERALIZED CAPABILITY OF FILTRATION SYSTEMS
TO ACCO* ODATE PW WATER OUALITY CONDITIONS
Genera] Restrictions
Total
Col iforns Turbidity Color
Treatment ( * /100 ml LhTU) ACU )
Conventional with
predisinfection c20 ,0OO ho restrictions
Conventional without
predisinfection <5,QQQC3) Mo restrictions <75 (2 )
Direct filtration
sith flocculation < ø) <7- 14°
In-line filtration 
-------
— No fflter to waste
- Intermittent operation
- Sudden rate changes
- Poor housekeeping
- Operating the filters after turbidity breakthrough
Studies of slow sand filtration have shown that this technology
(without disinfection) is capable of providing greater than a 3-log
removal of Giardia cysts and greater than a 3-log removal of viruses.
Factors which can adversely affect removal efficiencies include:
- Poor source water quality
— Cold water conditions
- Increases in filtration rates
— Decreases in bed depth
- Improper sand size
— inadequate ripening
Diatomaceous earth (DE) filtration can achieve greeter than a 3-log
removal of Giardia cysts when sufficient precoat and body feed are used.
However, turbidity and total colifonn removals are strongly influenced by
the grade of DE employed. Conversely, DE filtration is not very effecti’ e
for removing viruses unless the surface properties of the diatomaceous
earth have been altered by pretreatment of the body feed with alum or a
suitable polymer. In general, DE filtration is assumed to achieve only
a 1—log removal of viruses unless demonstrated otherwise. Factors which
can affect the removal of Glardla cysts and viruses Include:
• Precoat thickness
— Amount of body feed
- Grade of DE
— Improper conditioning of septum
— Improper pretreatment of the body feed
Package plants can be used to treat water supplies for camounities
as well as for recreational areas, parks, construction camps, ski resorts,
military installations and other facilities where potable water is not
available from a municipal supply. Operator requirements vary signifi-
cantly with specific situations. Under unfavorable raw water conditions,
4-4

-------
package plants could demand ful 1—time attention. Package plants are most
widely used to treat surface supplies for re moval of turbidity, color and
coliform organisms prior to disinfection. They are currently available
in capacities up to 6 mgd.
Colorado State University conducted a series of tests on one package
plant over a 5-month period during the winter of 1985-86 (Horn and
Hendricks, 1986). Existing installations in Colorado had proven effective
for turbidity removal, and the tests at the university were designed to
evaluate the system’s effectiveness in removing coliform bacteria and
Giardia cysts from low turbidity, low temperature source waters. The test
results showed that the filtration system could remove greater than
99 percent of Giardia cysts for waters which had less than 1 iflU turbidity
and less than 5 C temperatures, as long as proper chemical treatment was
applied, and the filter rate was 10 gpm/ft’ or less. In addition, an
alternate water source having a turbidity ranging from 3.9 to 4.5 NTtJ was
used in 12 test runs with coagulant doses ranging from 15 to 45 mg/I. The
effluent turbidities from these runs were consistently less than 0.5 NTU.
Surveys of existing facilities Indicate that while package plants
may be capable of achieving effective treatment 4 many have not consistent-
ly met the interim MCL for turbidity, and in some cases, coliforms were
detected in the filtered water (Morand et al., 1980; Horand and Young,
1983). The performance difficulties were primarily the result of the
short detention time inherent In the design of the treatment units, the
lack of skilled operators with sufficient time to devote to operating the
treatment facilities 1 and the wide-ranging variability in quality of the
raw water source. For instance, raw water turbidity was reported to often
exceed 100 NW at one site. Improvements in operational techniques and
methods at this site resulted in a substantial Improvement in effluent
quality. After adjustments were made, the plant was capable of producing
a filtered water with turbidities less than 1 $111, even when influent
turbidities Increased from L i to 100 NTIJ within a 2 —hour period 1 as long
as proper coagulation was provided.
One of the major conclusions of these surveys was that package water
treatment plants manned by competent operators can consistently remove
4-5

-------
turbidity and bacteria from surface waters of a fairly uniform quality.
Package plants applied where raw water turbidities are variable require
a high degree of operational skill and nearly constant attention by the
operator. Regardless of the quality of the raw water source, all package
plants require at least a minimum level of maintenance and operational
sk ll and proper chemical treatment if they are to produce satisfactory
water quality.
Cartridge filters using microporous filter elements (ceramic, paper
or fiber) with pore sizes as small as 0.2 urn may be suitable for producing
potable water from raw water supplies containing moderate levels of
turbidity, algae and microbiological contaminants. The advantage to small
systems of these cartridge filters is that, with the exception of
disinfectant, no other chemicals are required. The process is one of
strictly physical removal of small particles by straining as the water
passes through a porous cartridge. Other than occasional cleaning or
cartridge replacement, operational requirements are not complex and do not
require skilled personnel. However, the SWTR does require each surface
water system to be operated by a qualified operator, as determined by the
Primacy Agency. Such a system may be suitable for some small systems
where, generally, only maintenance personnel are available for operating
water supply facihties. However, the use of cartridge filters should be
limited to low turbidity source waters because of their susceptibility to
rapid headloss buildup. For example, manufacturer’s guidelines for
achieving reasonable filter run lengths with certain polypropylene filter
elements are that the raw water turbidity be 2 NTU or less (USEPA, 1988b).
Long (1983) analyzed the efficacy of a variety of cartridge filters
using turbidity aeasurements, particle size analysis, and scanning
electron microscope analysis. The filters were challenged with a
suspension of sicrospheres averaging 5.7 UI in diameter which is smaller
than a Glirdia cyst. The microspheres were applied at a concentration of
40,000 to 65,000 spheres per ml. Ten of 17 cartridge filters removed over
99.9 percent of the microspheres.
In tests using live Infectious cysts fros a bUIan source, cartridge
filters were found to be highly efficient in removing Giardla cysts
4-6

-------
(Hibler, 1986). Each test involved challenging a filter with 300,000
cysts at a concentration of 10,000 cysts/mi. The average removal for five
tests was 99.86 percent, with removal efficiencies ranging from 99.5 per-
cent to 99.99 percent.
The application of cartridge filters to small water systems using
either cleanable ceramic or disposable polypropylene cartridges appears
to be a feasible method for removing turbidity and most microbiological
contaminants. However, data regarding the ability of cartridge filters
to remove viruses are not available. Since disinfection by itself could
achieve a 4-log inactivation of viruses, if the cartridge filter removes
greatev than or equal to 3 logs of Giardia , then the filter plus
disinfection would achieve the overall minimum requirements, regardless
of whether only negligible Giardia Inactivation is achieved (e.g., less
than 0.5 log). However, consideration should be given to the feasibility
of providing multiple barriers of treatment for each target organism,
I.e., some Giardia and virus removal by each barrier (I.e., some removal
by filtration and some inactivation by disinfection) as protection In case
one of the barriers fails. The efficiency and economics of the process
must be closely evaluated for each situation. Pretreatment in the fonn
of roughing filters (rapid sand or multi-media) or fine mesh screens may
be needed to remove larger suspended solids which, if not removed, could
cause the rapid buildup of headloss across the cartridges (USEPA, 1988a).
In general, conventional treatment, direct filtration, slow sand
filtration and diatosaceous earth filtration can be designed and operated
to achieve the maximum removal of the water quality parameters indicated
in Table 4-1. However, for the purpose of selectinQ the appropriate
filtration and disinfection technologies and for determining design
criteria, these filtration processes should be assumed to achieve a 2-log
removal of Giardla cysts and a 1—log removal of viruses. This conserva-
tive approach will assure that the treatment facility has adequate
capability to respond to non-optimum performance due to changes In raw
water quality, plant upsets, etc. The balance of the required removals
and/or Inactivation of Glardla cysts and viruses would be achieved through
the application of appropriate disinfection.
4-7

-------
The performance of alternate technologies such as cartndge filters,
and possibly package plants. depending upon the unit under consideration
cannot be stated with certainty at this time. Because of these perform-
ance uncertainties. pilot studies should be used to demonstrate their
efficacy for a given water supply.
4.2.3 Selection
For any specific site arid situation, a number of factors will
determine which filtration technology is most appropriate. Among these
are: raw water quality conditions, space and personnel availability, and
economic constraints. A discussion of the impact of raw water quality on
the technology selection Is presented here. The Impact of site-specific
factors and economic constraints is pre5ented in the USEPA document
ulechnologies and Costs for the Removal of MicrobLal Contaminants from
Potable Water Supplies (USEPA, 1988b).
Raw Water Quality Conditions
The number of treatment barriers provided should be coimnensurate
with the degree of contamination in the source water. The four technolo-
gies specified in the SWIR vary in their ability to meet the performance
criteria when a wide range of raw water quality Is considered. While the
numerical values of raw water quality that can be accoemodated by each of
the four technologies will vary from site to site, general guidance can
be provided. General guidelines for selecting filtration processes, based
on total coliform count, turbidity, and color are presented In Table 4-2.
It is not rec ended that filtration systems other than those listed in
Table 4-2 be used when the general raw water quality conditions exceed
the values listed, unless It has been demonstrated through pilot testing
that the techilology can meet the performance criteria under the raw water
quality conditions expected to occur at the site.
The filtration processes listed in Table 4-1 are capable of
achieving the required performance criteria when properly designed and
operated If they are treating a source water of suitable quality (i.e.,
generally within the ranges indicated In Table 4-2). One of the causes
44

-------
of filtration failures is the use of inappropriate technology for a given
raw water quality (Logsdon 1 1987b). These criteria are general guide-
lines. Periodic occurrences of raw water coHform turbidity or color
levels In excess of the values presented in Table 4—2 should not preclude
the selection or use of a particular filtration technology. For example,
the following alternatives are available for responding to occasional raw
water turbidity spikes:
a. Direct Filtration
- Continuous monitoring and coagulant dose adjustment
— More frequent backwash of filters
— Use of presedimentation
b. Slow Sand Filtration
- Use of a roughing filter
— Use of an Infiltration gallery
c. Diatomaceous Earth Filtration
- Use of a roughing filter
- Use of excess body feed
For the above alternatives, EPA recoemends that pilot testing be
conducted to demonstrate the efficacy of the treatment alternative.
The characteristics of each filtration technology are a major factor
in the selection process. Significant characteristics include performance
capabilities (contaminant removal efficiencies), design and construction
requirements, and operation and maintenance requirements. Details
regarding each of the four filtration technologies are presented in the
following section.
4.3 Available Filtration Technologies
4.3.1 Introduction
As Indicated In the preamble to the SWTR. the historical responsi-
bility of the States to establish design and operating criteria for public
drinking water plants will continue. The purpose of the following
sections Is to provide guidance on how the design and operating criteria
may need to be changed in order to assure that the performance criteria
in the SWIR are set.
4-9

-------
The design criteria for the various filtration technologies found
in the 1987 edItion of Reconmiended Standards for Water Works (Great Lakes,
1987) are the minimum design criteria that a majority of states are
currently following. 2 These standards are referred to as Ten States
Standards in the remainder of this manual. The design criteria contained
in the Ten States Standards have not been duplicated here. Rather, the
reader is referred to the Ten States Standards directly. EPA recoiTsnends
the following additions and/or changes to the Ten State Standards in order
to assure compliance with the performance criteria of the SWTR.
4.3.2 General
The following recocinendatlons apply to all filtration plants:
a. All filtration plants should provide continuous turbidit
monitoring of the effluent turbidity from each lndividua
filter)’ If continuous monitoring is Impractical, routine
monitoring of individual filters Is recomeended as a minimum.
b. All filtration systems should be concerned with the peak
turbidity levels in the filtered water after backwashing and
Based upon the results of a survey conducted for the American Water
Works Association Research Foundation (AWWARF), same 38 states use the
Ten States Standards entirely or in modified form (AWWARF, 1986).
Although this Is not a requirement of the SW1R, it Is reco ended
because of the possibility that not all filters In a treatment plant
will produce the same effluent turbidity. This say be due to a variety
of conditions that include bed upsets, failure of media support or
underdraln systems, etc. Although the c ined effluent from all the
filters may meet the turbidity requirements of the SWIR, the turbidity
level (to. an individual filter may substantially exceed the limits.
This may result In the passage of Glardla cysts or other pathogens.
‘ Validation should be performed at least twice a week based on the
procedure outlined in Part 214A in the 16th EditIon of Standard Methods.
it should be noted that 1 roper installation of continuous monitors
may allow for air bubbles to enter the monitor resulting in false
turbidity spikes. To avoid air bubbles reaching the turb1 iseter the
sa le tap should be Installed below the center line of the pipe and
an air release valve say be Included on the sa le line.
4-10

-------
make every attempt to operate the filters to minimize the
magnitude and duration of these turbidity spikes. 5
Individual filters should be monitored as discussed in Section
4.3.2.a and when excessive turbidity spikes are found, corrective actions
taken. During these turbidity peaks, Giardia cysts and other pathegens
may be pissed into the finished water. There is evidence that a 0.2 to
0.3 NTU increase in the turbidity during the first period of the filter
run can be associated with rises in Giardia cyst concentrations by factors
of twenty to forty (Logsdon, 1985). Special studies should be conducted
to determine the extent of the turbidity spike problems.
There are basically four approaches available for correcting
problems with turbidity spikes after backwashing. These are as follows
(Bucklim, at al 1988):
- Proper chemical conditioning of the influent water to the
filter can minimize the magnitude and duration of these
turbidity spikes. This could include proper control of the
primary coagulant chemicals such as alum or iron compounds.
In some cases filter aids using polymers may be needed to
control the turbidity spikes.
— Gradually increasing the filtration rate in increments when
placing the filter in operation. Starting the filter at a low
flow rate and then Increasing the flow in small increments
over 10 to 15 minutes has been shown to reduce the turbidity
spikes in some cases (Logsdon, 1987).
— Addition of coagulants to the backwash water has also been
shown to reduce the extent of turbidity spikes after backwash.
Typically the same primary coagulant used in the plant Is
added to the backwash water. Polymers alone or In combination
with the primary coagulant may also be used.
— Filter—to-waste may be practiced where a portion of the
filtered water Isiediately after starting the filter is
wasted. This Is only possible where the filter system has
For most high rate granular bed filters, there is a period of
conditioning 1 or break-in imediately following backwashlng. during
which turbidity and particle removal is at a minimum, referred to as
the break-in period. The turbidity peaks are thought to be caused by
re iants of backwash water within the pores of and above the metha
passing through the filter, and/or floc breakup during the filter
ripening period before ft can adequately remove influent turbidity.
4-11

-------
provided the necessary valves and piping to allow this
procedure. There is some concern whether or not this practice
is beneficial. The extra valve operations needed for filter.
to—waste can disrupt the filter flow rate to the extent that
they create their own turbidity spikes. Some knowledge of the
time actually needed for filter-to-waste is also needed before
it can be determined that this Is an effective procedure for
controlling turbidity spikes. If the length of time the
filter-to—waste is practiced Is less than that before the
turbidity spike passes, the disruption caused by the valve
operation may actually Increase the turbidity spike.
Different plants and the individual filters within the plant may
have different turbidity spike characteristics. The four approaches
presented above, therefore, must be evaluated on a case-by—case basis.
Special studies will be required to identify those filters with the
turbidity spike problems and assist In selecting which of the four
approaches is best for correcting the problem. It has been generally
found that turbidity spikes can be minimized through one or a combination
of the first three approaches.
In order to establish filter-to-waste operating guidelines, the
following procedure Is suggested:
— Review the effluent turbidity data for each filter and deter-
mine which filter historically has the highest effluent tur-
bid I ty.
— Following backwashlng of the filter with the poorest perfor-
mance, place that filter into service and collect grab samples
every 5 to 10 minutes for a period of at least 60 minutes. 6
— Analyze the grab sa ,les for turbidity and determine how long
the filter aist be In operation before the effluent turbidity
drops
— to less than or equal to 0.5 NIh
- or 1 NTU in cases where a filtered water turbidity of
less than or equal to 1 NTU is allowed.
‘ Continuous turbidity monitoring can be used In place of grab sampling.
4-12

-------
Limited intonation exists on the typical magnitude and duration of
peak turbidity levels after backwashing and what levels are considered
acceptable to assure that these turbidity spikes are not associated with
passage of Glardia cysts. Information from plant scale tests, showing
the typical magnitude and duration of these turbidity spikes is available
from two plants (Bucklin et al. , 1968). Studies conducted at these plants
over a year showed that these peaks occurred within the first few minutes
after the filter was placed back in operation, their effects lasted for
several hours, and varied in magnitude from 0.08 to 0.35 NTU on average.
For existing plants without provisions for filter-to-waste, the
decision to add the necessary piping to provide this capability should be
made only after carefully evaluating the other three approaches. If the
results of special studies show that the other three options are not
effective in minimizing the turbidity spikes then the expense of adding
the filter-to—waste capabilities may be Justified.
For new plants the capability of filter—to-waste may be required by
the Primacy Agency or should be considered. By having this capability,
additional flexibility will be available for turbidity spike control.
This flexibility may also be useful for other filter maintenance functions
such as after media replacement or when heavy chlorination of the filter
is needed after maintenance.
4.3.3 Conventional Treatment
Conventional treatment is the most widely used technology for
removing turbidity and uicrobial contaminants from surface water supplies.
Conventional treatment includes the pretreatment steps of chemical
coagulation, rapid mixing, flocculation and sedimentation followed by
filtration. These conventional treatment plants typically use aluminum
and Ira c ounds in the coagulation processes. Polymers say also be
used to enhance the coagulation and filtration processes. A flow sheet
for a conventional treatment plant is presented on Figure 4-1.
Lime softening is a treatment process used to reman hardness and
turbidity from surface waters. Treatment Is typically accopilished with
conventional process units. The lime softening process removes the
4-13

-------
COAGULANTS
* OR ALTERNATE SOLIDS REMOVAL PROCESS
FIGURE 4-1 FLOW SHEET OF A TYPICAL CONVENTIONAL
WATER TREATMENT PLANT

-------
calcium and magnesium from the water by precipitating them as calcium
carbonate and magnesium hydroxide. Turbidity levels in the water are also
reduced by this process. Lime and possibly soda ash is added to the raw
water to raise its pH to a point at which these precipitates are formed
and then removed from the water during sedimentation and filtration. lime
softening may be used for the removal of carbonate hardness in the pH
range of 9 to 10 through a single stage process. Two-stage lime/soda ash
softenrng at a pH of 10 to 12 can be used for the removal of non-carbonate
hardness and magnesium. Two-stage softening includes recarbonation to
neutralize the caustic alkaflnity , reducing the pH to the range of 8.5 to
9.5. A flow sheet for typical one— and two-stage softening plants Is
presented on Figure 4-2.
Each of these three conventional treatment processes uses filtration
following sedimentation. Three different types of filters are used. Sand
filters, normally found In older plants, use a single media of sand to
form a filter bed, and are generally designed with a filtration rate of
2 gpmfft 1 . ? ewer plants normally use dual—media or mixed media filters.
Dual media filters use a combination of anthracite coal along with a sand
to form the filter bed. Mixed media filters use coal, sand, and a third
material to form the filter bed. Dual and mixed media filters can be
designed to operate at higher filtration rates than sand ftlters, i.e.,
4 to 6 gpm/ft .
Design Criteria
The ainlaaa design criteria In the Ten State Standards for
conventional treatment are considered sufficient for the purposes of
complying with the SWIR with the following addition:
— The criteria for sedimentation should be expanded to include
other methods of solids removal including dissolved air
flotation. Plate separation and upflaw—sol$ds contact
clariflers Included in the 1987 Ten State Standards should
also be considered.
Doerattng Reoulresents
In addition to the operating requirements in the Ten State
Standards, a coagulant should be used at all times the treatment plant is
4-14

-------
sr . II
LIME
(13 PH RANGE 9 -10
121 OR ALTERNATE SOLIDS REMOVAL PROCESS
TWO STAGE SOFTENNG (ii
INFLUENT
LIME
FIGURE 4•2 FLOW SHEET OF A TYPICAL CONVENTIONAL
WATER TREATMENT PLANTS
SODA ASH
(13 PH RANGE 11.12
SOFTENED WATER

-------
in operation. Conventional and direct filtration plants must be monitored
carefully because failure to maintain optimum coagulation can result in
poor filter performance and breakthrough of cysts and viruses. Although
the detention time provided by the settling basins results in some margin
of safety, the loss of coagulation control at the chemical feed or rapid
mix points may not be noticed until the poorly coagulated water reaches
the filters, after the process has failed. Failure to effectively monitor
and control filter operation can result in undetected poor filter
performance (Logsdon, 1g87a; Logsdon, 1987b).
Effective operation of a conventional treatment plant requires
careful monitoring and control of:
- Chemical Feed
- Rapid Mix
— Flocculation
— Sedimentation
— Filtration
For the purposes of the SWTR, the requirements for effective
operation of a conventional water treatment plant can be suninarized as
follows:
a. The application of a coagulant and the maintenance of
effective coagulation and flocculation at all times when a
treatment plant Is in operation.’ Proper process control
‘ Oependable removal of Giardla cysts can not be guaranteed if a water
is filtered without being properly coagulated (Logsdon, 1987b; Al-Ani
et al., 1985). ThIs Is true even If the raw water turbidity is less
than 1 $11).
‘ A Indicated In the prea le to the proposed MR. 33 percent of the
reported cases of giardlasis in waterborne disease outbreaks were
attributed to 1 roperly operated filtration plants.
‘ S conventional water treatent plants which treat low turbidity
source waters (4 NTU) reportedly discontinue the application of
coagulant(s) during periods of law turbidity since the raw water airead
meets the turbidity MCI. H ver , studies have shosm that cyst r ova
for low turbidity waters is the most difficult to achieve end requires
optla pretreatment including coagulation to achieve effective removals
4-15

-------
procedures sh u)d be used at the plant to assure that chemical
feeds are adjusted and maintained in response to variations
In raw water temperature and turbidity.
b. Maintenance of effectuwe filtration will require proper
operation procedures to meet the turbidity requirements of the
SWTR. Proper operation should include:
— Proper chemical conditioning of the water ahead of the
filter to assure adequate turbidity removal through the
filter.
- Control of the flow rates and elimination of rapid
changes in flow rate applied to the filter.
- Backwashing of filters before the ft Itered water quality
is degraded to the point that the plant fails to meet
the turbidity requirements of the SWTR. The criteria
on which to base initiation of backwash will have to be
determined for each plant. £xperience with operation
cycles including run times and headloss data may serve
as the basis for this site specific criteria.
— After backwash bringing the clean filters back on line
so that excessive turbidity spikes in the filtered water
are not created. Section 4.3.2.8 of this manual
discusses these turbidity spikes and approaches
available to minimize them.
c. Filters removed fros service generally should be backwashed
upon start—up. However, In some cases, It may be 1 ractIcal
to backwash filters each time they arm removed fro. service.
Accordingly, the Primacy Agency may choose to allow start-up
without backwashing under certain conditions on a site-by-site
basis. in making this decision, the following should be
considered:
• the length of time the filter was off-line
— performance of the filter while being put on-line
The filter should be brought back on-line In such a way that
no turbidity spikes that could be associated with passage of
(Al—MI et al. 4 1985).
4 .16

-------
Giardip cysts and other pathogens occur. U problems with
turbidity spikes are found when starting up dirty filters,
special studies should be used to evaluate if any of the
approaches discussed in Section 4.3.2.B of this manual are
effective in minimizing the turbidity spikes.
4.3.4 Direct Filtration
A direct filtration plant can include several different pretreatment
unit processes depending upon the application. In its simplest form, the
process includes only in-line filters preceded by chemical coagulant
application and mixing. The mixing step, particularly in pressure
filters, can be satisfied by influent pipeline turbulence. In larger
plants with gravity filters, an open rapid-mix basin with mechanical
mixers typically Is used. Figure 4-3 illustrates the unit processes of
a typical direct filtration plant.
Another variation of the direct filtration process consists of the
addition of a coagulant to the raw water followed by rapid mixing and
flocculation, as illustrated on Figure 4-4. The chemically conditioned
and flocculated water Is then applied directly to a dual- or multi-media
filter (USEPA, 1988b).
Design Criteria
The 1987 edItion 0 f the Ten State Standards recomeends pilot studies
to determine most design criteria. For the purposes of l lementation of
the SWTR this requirement is considered sufficient with the following
exception:
a. A coagulant must be used at all times when the treatment plant
is In operation)°
10 Optimum coaoulatton Is critical for effective turbidity and microbiolog-
ical removals with direct filtration (Al—Mi et aL, 1985).
4-17

-------
COAGULANT!
LUNT lIIIiIUI__UItqNf JU
) IEC . 2 N
DtT INTIOId
DUAL O MULTI.
M A FLTEN
4 2
FIGuRE 4.3 FLOW SHEET FOR A TYPiCAL
DIRECT FILTRATION PLANT
FIGURE 4.4 FLOW SHEET FOR A TYPIr.AL DIRECT
FILTRATION PLANT WITH FLOCCULATION
H
CO GUtANY$
INPLUEWT 1

-------
Onerating Reaul rerr’entj
Operating considerations for direct filtration plants are essential-
ly identical to those for conventional treatment plants. The major
difference is that a direct filtration plant will not have a clarifier,
and may or may not have a flocculation or contact basin. n addition, EPA
recomends that all direct filtration plants both new and existing, be
required to make provisions to minimize the break-in time of a filter
being put on -i ine. 1
As with conventional treatment, the initiation of backwashing a
filter should first be based on filter effluent turbidity values, then by
headloss and run time. Effluent turbidity monitoring equipment sfriould be
set to Initiate filter backwash at an effluent value of 0.5 NTU or less,
in order to meet filtered water quality requirements. Also, any filters
removed from service should be backwashed upon start-up. in some cases,
it may not be practical to backwash filters every time they are removed
from service. This decision should be made by the Primacy Agency on a
case-by-case basis 1 based on the same considerations as for conventional
Systems.
4.3.5 Slow Sand Filtration
Slow sand filters differ from single-media rapid-rate filters in a
number of Important characteristics. In addition to the difference of
flow rate, slow sand filters:
a. Function using biological mechanisms as well as physical-che-
mical mechanisms
b. Use smaller sand particles
c. Are not backwashed, but rather are cleaned by removing the
surface media
d. Live much longer run times between cleaning
“ As with conventional treatment, direct filtration produces a relatively
poor quality filtered water at the beginning of filter runs and
therefore a filter-to—waste period Is recoended. In sc.e cases, the
addition of a filter aid or bringing flit.rs on-line slowly will be
appropriate (Cleasby et aL, 1984).
4-18

-------
e. Require a ripening period at the beginning of each run
Although rapid rate filtration is the water treatment technology
used most extensively in the United States its use has often proved
inappropriate for small coarunities since rapid-rate filtration is a
technology that requires skilled operation by trained operators. Slow
sand filtration requires very little control by an operator. Consequent-
ly, use of this technology may be more appropriate for small systems where
source water quality is within the guidelines reconrended in Section
4.2.3.
As Indicated in this section, slow sand filtration also may be
applicable to other source water quality conditions with the addition of
pretreatment such as a roughing filter or presedimentation.
Design Criteria
The minimum design criteria presented in the Ten State Standards for
slow sand filters are considered sufficient for the purposes of implemen-
tation of the SWTR with the following exceptions:
a. Raw water quality limitations should be changed to reflect the
values given in Table 4.2.12
b. The effective sand size should be between 0.lSa and O.35nin
rather than the current 0.30 a to 0.45
Additional guidance on the design of slow sand filtration is
available In the design manual entitled Slow Sand Filtration for Conrunitv
Water Suoolf es Technical Paoer 24. 1981 published by the International
“ Vitbout pretreatment. limitations exist in the quality of water that
is suitable for slow sand filtration (L.ogsdon, 1987b; Cleasby et al. ,
1984; Bellamy et al. 1 1985; Fox et al. 1 1983).
“ Significant decreases in total colifori re.ovals were shown at effective
sand sizes less than 0.35 a (Bellamy et al., 1985). As defined in the
AWWA Standard for Filtering Material, effective site is the size opening
that will pass 10 percent by weight of a sample of filter material.
4-19

-------
Reference Centre for Comunity Water Supply and Sanitation (CRC),
P.O. Box 5500, 2280 HM Rijswijk, the Netherlands.
Qoerating Requirements
Maintenance of a slow sand filter involves two periodic tasks:
a. Removal of the top 2 to 3 cm (0.8 to 1.2 inches) of the
surface of the sand bed when the headloss exceeds 1 to 1.5 m.tl
b. Replacement of the sand when repeated scrapings have reduced
the depth of the sand to approximately one—half of its design
depth (Bellamy et al., 1985).
Following scrapii g, slow sand filters produce poorer quality
filtrate at the beginning of a run, and a filter-to-waste or ripening
period of one to two days is rec im ended before use to supply the system.
The ripening period is an interval of time lemediately after a scraped
filter is put back on.llne. when the turbidity or particle count results
are significantly higher than the corresponding values for the operating
filter. Curing this time, the microorganisms multiply and attain
equilibrium in the usch Jtzdecke.e Filter effluent monitoring results
should be used to determine the end of the ripening period. For example,
a turbidimeter could be set at 1.0 IITU or less to Initiate start of the
filter run.
When repeated scrapings of the sand have reduced the depth of the
sand bed to approximately one-half of Its design depth, the sand should
be replaced. Filter bed depths of less than 0.3 to 0.5 a (12 to 20
inches) have been shown to result In poor filter perforaance (Bellamy et
al., 1985). The replacement procedure should include removal of the
remaining sand d im to the gravel support, the addition of new sand to one
half of the design depth and placement of the sand previously removed on
top of the mu sand)S
Removal of this top layer of the ‘Sch.utzdecke’ should restore the
filter to Its operational capacity and Initial headloss.
“ This procedure results in clean sand being placed in the bottom half
of the filter bed and biologically active sand In the top half reducing
the amount of time required for the curing period. It also provides
4-20

-------
The amount of time for the biological population to mature in a new
sand filter (also called curing) and to provide stable and full treatment
varies. The World Health Organization (1980) reported that curing
requires a few weeks to a few months. Fox et al., (1983) found that
“about 30 days” were required to bring particle and bacterial effluents
down to a stable level. All researchers agree that a curing time for a
new filter is required before the filter operates at its fullest potential
(Bellamy et al., 1985).
4.3.6 Diatomaceous Earth Filtration
Diatomaceous earth (D o filtration, also known as precoat or
diatomite filtration, is appropriate for direct treatment of surface
waters for removal of relatively low levels of turbidity and microorgan-
isms.
Diatomite filters consist of a layer of DO about 3 me (1/8 inch)
thick supported on a septum or filter element. The thin precoat layer of
DE must be supplemented by a continuous body feed of diatomite, which is
used to maintain the porosity of the filter cake. If no body feed is
added, the particles filtered out will build up on the surface of the
filter cake and cause rapid increases in headloss. The problems inherent
in maintaining the proper f lim of DO on the septum have restricted the use
of diatomite filters for municipal purposes, except under certain
favorable raw water quality conditions, i.e. 1 low turbidity and good
bacteriological quality. Specific upper limits of raw water quality
parameters are not well-defined because diatomaceous earth filtration
performance depends on the nature, as well as the concentration, of the
raw water particles and the grades of diatomite e loyed. Logsdon (lQSlb)
reported that filtered water turbidities above 1 ITU and short filter runs
were observel for several diatomaceous earth plants having maximum raw
water turbidities above 20 NTU.
for a c lete exchange of sand over time, alleviating potential
problems of excessive silt accumulation and clogging of the filter bed
(Bellamy et al., 1985).
4-21

-------
Design Criteria
The minimum design criteria presented in the Ten State Standards for
diatomaceous earth filtration are considered sufficient for the purposes
of compliance with the SWTR with the following exceptions:
a. The recoimnended quantity of precoat is 1 kg/rn 2 (0.2 pounds per
square foot) of filter area, and the minimum thickness of the
precoat filter cake is 3m to 5nn ( 1/8 to 1/5-inch).’ 6
b. Treatment plants should be encouraged to provide a coagulant
coating (alum or suitable polymer) of the body feed. 11
ODerat ing Requirements
Operating requirements specific to DE filters Include:
- Preparation of body feed and precoat
Verification that dosages are proper
— Periodic backwashing and disposal of spent filter cake
- Periodic inspection of the septum(s) for cleanliness or damage
- Verification that the filter is producing a filtered water
that meets the performance criteria
4.3. 1 Alternate Technologies
The SWTR allows the use of filtration technologies other than those
specified above provided that the system demonstrates to the Primacy
Agency using pilot studies or other means that the filtration technology
when combined with disinfection achieves at least 3-log Giardia cyst and
4-log virus removal/inactivation. Such technologies aist also meet the
turbidity performance criteria for slow sand filtration. Guidance for
“ Studies have shown that a precoat thickness of 1 k 9 /d (0.2 lbs/ft 2 ) was
most effective in Glard ia cyst removal and that the precoat thickness
was more i ortant than the grade size in cyst removal (DeWalle et al.
1984; Logsdon et al., 1981; Bellamy •t al., 1984).
u Although enhancement of the DE is not required for Giardia cyst removal,
coagulant coating of the body feed has been found to significantly
improve removals of viruses, bacteria and turbidity. (Brown et al.,
1974; Bellamy et al., 1984).
4-22

-------
conducting pilot studies to demonstrate this effectiveness is provided in
Appendix H of this manual.
Reverse osmosis is a membrane filtration method which is used for
desalination and/or the removal of organic contaminants. The treatment
process it effective for the removal of Giardia cysts and viruses and no
demonstration is necessary.
Alternate filtration technologies which are currently available
include, but are not limited to:
a Package Plants
— Cartridge Filters
Package plants in principle are not a separate technology from the
preceding technologies. However, in many cases they are different enough
in design criteria, and operation and maintenance requirements that they
should be considered as an alternate technology. The package plant is
designed as a factory-assembled, skid-mounted unit generally incorporating
a single, or at most, a few process units. A complete treatment process
typically consists of chemical coagulation, flocculation, settling and
filtration. Package plants generally can be applied to flows ranging from
about 25,000 gpd to approximately 6 mgd (LISEPA, 1988b). In cases where
the Primacy Agency believes that the design criteria of the package plant
corresponds to the design criteria of the processes established earlier
in this section (i.e., that the package plant qualifies as conventional
or direct filtration), the requirement of pilot testing may be waived.
The application of cartridge filters using either cleanable ceramic
or disposable polypropylene cartridges to small water systems may be a
feasible method for removing turbidity and some microbiological contami-
nants, such as Giardia cysts although no data are available regarding
their abilityto remove viruses. Pilot studies are required to demon-
strate th. efficacy of this technology for a given supply. However, if
the technology was d nstrated to be effective through pilot plant
studies at one site, then the technology could be considered to be
effective at another site which had si.ilar source water quality
conditions. Therefore, pilot plant testing at the new site might not be
necessary.
4-23

-------
It is important to note that the demonstration of achieving the 3-
log Giardia cyst and 4-log virus removal/inactivation requirements
includes disinfection. Thus, if a cartridge filter is demonstrated to
achieve a 3—log removal of Giardia cysts and it is determined by Cis that
the disinfection achieves at least a 4-log virus inactivation, the
effectiveness of the technology would be demonstrated. The technology
must also maintain turbidities less than 1 NTU in 95 percent of the
monthly samples. Meeting this turbidity requirement assures a high
probability that turbidity will not interfere with disinfection and that
the inactivation efficiencies predicted by the Cis are reliable.
Design Criteriç
After any necessary pilot studies are conducted and a successful
demonstration of performance has been made, design criteria should be
established and approved by the Primacy Agency. Eventually, a sufficient-
ly large data base will become available, making It easier to apply the
alternate technologies to other water supplies of similar quality.
Goerating Requirements
After any necessary pilot studies are conducted and a successful
demonstration of performance has been made, operating requirements should
be established and approved by the Primacy Agency.
4.3.8 Nontreatment Alternatives
Under certain circumstances, some systems say have other alterna-
tives available. These alternatives include regionalization and the use
of alternate sources 1
For small water systems which must provide filtration, a feasible
option may beto join with other small or large systems to form a region-
al water supply system. In addition, alternative water sources located
within a reasonable distance of a coanity which would all the system
to meet the requirements of the SlIER and other applicable drinking water
regulations, say be developed to provide a satisfactory solution to a
comeunity water quality problem. The availability of alternative ground
4-24

-------
water sources will depend upon the size and location of the system and
the costs involved.
4.4 Disinfection
4.4.1 General
The SWIR requires that disinfection be included as part of the
treatment of surface water for potable use. As noted earlier, EPA
reconrends that the number of treatment barriers be comensurate with the
degree of contamination in the source water in accordance with Table 4-2.
For example, as indicated in Table 4-2, when the total colifones in the
source water are greater than 5,000jIOO ml, conventional treatment with
predisinfection Is reconinended. However, the selection of appropriate
disinfection requires consideration of other factors in addition to than
those included In Table 4-2. These considerations include:
a. Source water quality and the overall removaltinactivatlon of
Glardia cysts and viruses desired.
b. Likelihood of 11104 fonsatlon.
c. Potential need for an oxidant for purposes other than
disinfection including control of taste, odor 1 iron,
manganese, color, etc.
4.4.2 Recoemended Removall lnactivation
The SWTR requires a minimum 3-log removal/Inactivation of Glardia
cysts and a mlnlsa 4-log removal/inactivation of viruses:
a. Well—operated conventional treatment plants which have been
opti.ized for turbidity removal can be expected to achieve at
least a 2.5-log removal of Giardla cysts.
b. Well—operated diatomaceous earth, slow sand filtration and
direct filtration plants can be expected to achieve at least
Zelog removal of 6iardia cysts.
EPA recomeends that:
a. Conventional filtration systems provide sufficient disinfec-
tion to achieve a minlsa of 0.5-log Giardia cyst and 2-log
virus inactivation.
4-25

-------
b. Slow sand f f ltratior systems provide sufficient disinfection
to achieve a minimum of 2-log Giardia cyst and 2-log virus
Inactivation.
c. Systems using diatomaceous earth and direct filtration, or
other filtration methods, should provide sufficient disinfec-
tion to achieve a minimum of 1-log Giardia cyst and 3-log
virus inactivation.
Further guidance on the disinfection level to be provided is
contained in Section 5. CT values for achieving these inactivations are
presented in Appendix £. As indicated in this Appendix:
a. A comparison of Tables (-1 through E-6 with Table E-7
indicates that systems which achieve a 0.5-log inactivation
of Giardfa cysts, using free chlorine, will achieve greater
than a 4-log inactivation of viruses.
b. Ozone and chlorine dioxide are generally more effective at
inactivating viruses than Giardia cysts. However, as
indicated in Tables £8 through E-11, there are some
conditions under which the disinfection needed to provide the
.recos ended virus inactivation is higher than that needed for
the recotrended Giard la cyst inactivation. Therefore, a
system using ozone or chlorine dioxide for disinfection must
check the CT values needed to provide the recomended
inactivation of both Giardla cysts and viruses and provide the
higher of the two disinfection levels. Systems may demon-
strate their efficiency for overall removal/inactivation using
the protocol in Appendices G and H.
c. As indicated in Tables £42 and £-13, chlorauines are such
less effective for inactivating Giardia cysts and viruses than
the other disinfectants. Also, chlorasines may be applied to
the system in several ways, either with chlorine added prior
to aania, aemonia added prior to chlorine or preformod. For
systems applying chlorine ahead of aemonia, the required level
of disinfection may be determined as follows:
- determine the CT needed to provide the required
inactivation of Giardia and viruses and provide the
higher of the two levels or
4-26

-------
- follow the protocol in Appendix G to demonstrate
effective inactivation to aHow lower levels of
disinfection.
For systems applying amonia ahead of chlorine or preformed
chioramines, the EPA reco1TI ends that the system demonstrate
effective virus inactivation according to the protocol in
Appendix G, since the CT values for virus inactivation in
Table E—13 only apply to the addition of chlorine prior to
ansnon i a.
Although the SWTR requires a minimum of a 3-log removal/inactivation
of Giardia cysts and a minimum of a 4—log removal/Inactivation of viruses,
It may be appropriate for the Primacy Agency to require greater removal s/—
inactivations depending upon the degree of contamination within the source
water.
Rose (1988) conducted a survey of water sources to characterize the
level of Giardta cyst occurrence for pollutedN and upristines waters.
Polluted waters are defined as waters in the vicinity of sewage and
agricultural wastes, while pristine waters are those originating from
protected watersheds with no significant sources of microbiological
contamination from human activities. EPA believes that treatment should
be provided to assure less than one case of microblologically-caused
illness per year per 10,000 people. In order to provide this level of
protection, 3, 4 or 5-log Giardla cyst removal/Inactivation should be
provided for the following source water qualities:
Giardla Cyst Removal/Inactivation Required BasedL S
on Source Water Cyst Concentration
Giardla Inactiyatlon 3-log 4-log S-log
Allowabl• daily avg
cyst concentration/lOG L 1 >1-10 >10-100
(geo.strlc mean)
Rose, 1988.
‘ 10 annual risk per person based on consumption of 2 lIters of water
daily.
4-27

-------
According to these guidelines, systems with sewage and agricultural
discharges to the source water should provide treatment to achieve an
overall 5-log removal/inactivation of jartip cysts, while the minimum
required 3-log removal/inactivation is sufficient for sources with no
significant microbiological contamination from human activities. A 4-log
removal/inactivation of cysts should be provided for source waters whose
level of microbiological contamination is between these two extremes. The
location of discharges or other activities polluting the water supply with
respect to the location of the intake should also be considered in
determining the level of removal/Inactivation needed. For instance, long
travel times and substantial dilution of a discharge will lessen the
impact of the discharge on the Intake water quality, In which case less
of an increase in the overall treatment recomended above, would be
warranted. It Is important to note that these levels of treatment for
different generalized source water characterizations are presented only
as guidelines. The Primacy Agency could develop disinfection requirements
based on these or other guidelines. It could also require systems with
available resources to conduct raw water monitoring for Giardia cyst
concentrations to establish the appropriate level of overall treatment and
disinfection needed.
The Primacy Agency may also review the nature of occurrence of
Giardia-sized particles In the raw water supply and the association with
turbidity occurrence. If It can be demonstrated that a higher degree of
removal of particles In the size range of Giardia Is accoi llshed when
turbidity levels and associated Giardla levels are elevated, then a log
removal credit higher than 3 could be allowed for that particular
treatment plant, during such occurrences. This credit should correspond
to the log particle re.oval efficiencies acc lished, as determined by
particle counting data, or turbidity data if properly qualified. In all
cases, a •lnl.u. of 0.5 log reduction of Glardla should be achieved by
disinfection In addition to the removal credit allowed for by other
treatment.
4-28

-------
Until a risk analysis for exposure to viruses Is developed, a rough
guideline for virus removal/inactivation, can be considered as follows:
a. For a 4-log Giardia cyst removal/inactivation, a 5-log virus
removal/inactivation is recoim ended.
b. For 5-log Giardia removal/Inactivation, a 6-log virus
removal/inactivation is recomended.
These guidehnes assume that virus occurrence in the source water
is roughly proportional to Glardia cyst occurrence, and that
- viruses occur at higher concentrations in source waters, or
- are more infectious than Giardia cysts and
- infections from viruses may have more health risk significance
than Giardla cysts.
Based on these assumptions, higher levels of protection are warranted.
To meet the levels of Inactivation recomended here, significant
changes in the system may be required. To avoid changes in the system
which may result in conflicts with future regulations, the Primacy Agency
may wish to establish interim disinfection levels to provide protection
of the public health prior to the promulgation of the disinfection
by-product regulations and then reconsider whether these levels are still
appropriate after the disinfection by-product regulations are promulgated.
Guidance for establishing Interim disinfection requirements is provided
in Section 5.5.
4.4.3 Total Trihalomethane (TTHH) Regulations
In addition to complying with disinfection requirements, systems
must meet the requirements of the TTI regulations. Currently, this
regulatiom Ineludes an NCL for TTHNs of 0.10 .g/L for systems which serve
greater than 10,000 people. EPA expects to Issue new regulations with a
lower MCI. In the near future. These regulations may also pertain to
systems serving less than 10,000 people. Therefore, the selection of an
appropriate disinfectant or disinfection strategy mist Include consid-
eration of current and future regulations.
4-29

-------
5. CRUTERIA FOR DETERMINiNG IF FILTRATION
AND DLSINFECTION ARE SATISFACTORiLY PRACTICED
5.1 Introduction
Under the SWTR , new and existing filtration plants must meet
specified monitoring and performance criteria in order to assure that
filtration and disinfection are satisfactorily practiced. These criteria
include
- Turbidity monitoring requirements
— Turbidity performance criteria
— Disinfection monitoring requ rements
— Disinfection performance criteria
The overall objective of these criteria is to provide control of:
Giardip cysts; viruses; turbidity; IIPC; and Legionella by assuring a high
probability that:
a. Filtration plants are well—operated and achieve maximum
removal efficiencies of the above parameters.
b. Disinfection will provide adequate inactivation of Giard a
cysts, viruses, HPC and Lepionella .
5.2 Turbidity MonitorinQ Reauirements
5.2.1 Samolinç Location
The purpose of the turbidity requirements for systems which use
filtration is to indicate:
a. Giardi a cyst and general particulate removal for conventional
treatment and direct filtration
b. General particulate removal for diatomaceous earth filtration
and slow sand filtration
c. Possible Interference with disinfection for all filtration
processes
To accomplish the purposes of the turbidity requirements,, the SWTR
requires that the turbidity samples be representative of the system’s
5-1

-------
filtered water. The sampling locations which would satisfy this
requirement include:
a. Combined filter effluent prior to entry into a clearwell,
b. Clearwell effluent;
c. Plant effluent or ininediately prior to entry into the
d strthution system; or
d. Average of measurements from each filter effluent.
The selection of sampling locations for demonstrating compliance
with the turbidity performance criteria is left to the system or the
preference of the Primacy Agency.
5.2.2 Sampling Freauencv
The turbidity of the filtered water must be determined:
a. At least once every four hours that the system is in
operation, or
b. The Primacy Agency may reduce the sampling frequency to once
per day for systems using slow send filtration or filtration
treatment other than conventional treatment, direct filtration
or diatomaceous earth filtration, if It determines that less
frequent monitoring is sufficient to indicate effective
filtration performance. For systems serving 500 or fewer
people, the Primacy Agency may reduce the sampling frequency
to once per day regardless of the type of filtration used if
it determines that less frequent monitoring is sufficient to
indicate effective filtration performance.
A system may substitute continuous turbidity monitoring for grab
sample monitoring if it validates the continuous measurement for accuracy
on a regular basis using a protocol approved by the Primacy Agency. EPA
recomeends tb.t the calibration of continuous turbidity monitors be
verified at least twice per week according to the procedures established
in Method 214A of the 16th EditIon of Standard Methods. 1
Although the 17th EdItion of Standard Methods Is available 1 the 16th
Edition Is referred to in the SWTP. Continuous turbidity monitors must
be installed properly to prevent air bubbles from reaching the monitor.
5-2

-------
5.2.3 Additional Monitoring
As indicated in Section 4.3.2, EPA reconrends that systems equip
each filter with a continuous turbidity monitor. This reconrendation is
not part of the requirements of the SWTR and is not required for
establishing compliance. Rather, it is reconrended as a toot for systems
to use to better monitor their treatment efficiency and to provide a
method for detecting a deterioration in filter performance.
If contmuous monitoring of each filter effluent cannot be
implemented, then EPA recomends that at least the following be conducted
on a quarterly basis:
a. Monitor each filter, either by grab samples or continuous
monitors, through the course of a routine cycle of operation,
i.e.: from restart to backwash
b. Visually inspect each filter where appropriate for indications
of physical deterioration of the filter
These are general suggestions. The Primacy Agencies are encouraged
to work with the systems to determine the best overall monitoring
program(s) for their particular filtration plants in order to assess the
status of the filter units. Each filter within a system should be
maintained so that each filter effluent meets the turbidity performance
criteria for the combined filter effluent (i.e.. the turbidity limits
specified in the SWTR).
5.3 Turbidity Performance Criteria
The SWift establishes turbidity performance criteria for each of the
filtration technologies. As previously indicated, these criteria provide
an indication of:
a. Effective particle and microbial removal
b. Potential for interference with disinfection
In filtration, effective particle removal depends on both physical
and chemical factors. The particles to be removed aist be transported to
the surface of the media and they must attach to the media. When
5—3

-------
efficient particle removal does not occur, the deterioration of filter
performance can be due to either physical problems with the filters or
problems with the treatment chemistry.
Physical problems which can result in a deterioration of filter
performance include:
a. Media loss
b. Media deterioration
c. Mud ball formation
d. Channeling or surface cracking
e. Llnderdrain failure
f. Cross-connections
In addition, the treatment chemistry has a significant impact on
filtration. Specifically, effective particle removal is a function of
the:
a. Raw water chemistry and the changes induced by the chemicals
added
b. Surface chemistry of the particles to be removed
c. Surface chemistry of the media
Consequently, when a filter experiences particle or turbidity breakthrough
prior to the development of terminal headloss, the search for alternatives
to correct the proble. must include not only an evaluation of the
potential physical causes but the treatment chemistry as well. Generally
this involves an evaluation of one or more of the following:
a. Alsernate coagulant type and/or dose
b. Alternate coagulant aid or flocculant aid type and/or dose
c. Need for an alternate oxidant type and/or dose
d. Need for a filter aid or alternate dose
5-4

-------
5.3.1 Conventional Treatment or Direct Filtration
The minimuni turbidity performance criteria for systems using
conventional treatment or direct filtration are:
a. Filtered water turbidity must be less than or equal to 0.5 NTU
in 95 percent of the measurements taken every month.
b. Filtered water turbidity levels of less than or equal to I N f l ]
in 95 percent of the measurements taken every month may be
permitted on a case—by-case basis if the Primacy Agency
determines that the system (filtration with disinfection) is
capable of achieving the minimum overall performance require-
ments of 99.9 percent removal/inactivation of Giardia cysts
at the higher turbidity level. Such a determination could be
based upon an analysis of existing design and operating
conditions and/or performance relative to certain water
quality characteristics. The design and operating conditions
to be reviewed include:
— the adequacy of treatment prior to filtration,
- the percent turbidity removal across the treatment
train, and
- level of disinfection.
Water quality analysis which may also be used to evaluate the
treatment effectiveness include particle size counting before
and after the filter. Pilot plant challenge studies
simulating full scale operation may also be used to demon-
strate effective treatment. Depending on the source water
quality and system size, the Primacy Agency will determine the
extent of the analysis and whether a pilot plant demonstration
is needed. For this demonstration, systems are allowed to
include disinfection in the determination of the overall
performance by the system. 2
c. Filtered water turbidity may not exceed 5 NTU at any time.
The Primacy Agency cam assume that conventional treatment plants
that are meeting the ul nimum performance criteria are achieving at least
a 2.5-log removal of Glardla cysts and at least a 2-log removal of viruses
prior to disinfection.’
2 Recoaended protocol for this demonstration is presented In Appendix P4.
‘ The literature indicates that well operated conventional treatment
plants can achieve up to 3—log reduction of Giardia cysts and viruses
{Logsdsori, 19Mb and Roebeck et al., 1962). Limiting the credit to 2.5-
logs for Giarlia cysts and 2-logs for viruses provides a margin of
safety by requiring more disinfection. This is consistent with the
5-5

-------
The Primacy Agency can assume that direct filtration plants that are
meeting the minimum perforsance criteria are achieving at least a 2-log
removal of Giardia cysts and a 1-log removal of viruses.’
Although the minimum turbidity performance criterion allows for a
maximum filtered water turbidity of 0.5 NTU, treatment facilities using
conventional treatment or direct filtration, whose raw water supplies have
turbidity levels of I NIL! or less, should be encouraged to achieve
filtered water turbidity levels of less than 0.2 NTU.’
Primacy Agencies may allow systems which believe that they are
actually achieving greater than a 2- or 2.5—log Giardia cyst removal to
demonstrate the actual removal achieved using the protocol outlined in
Appendix ii. It is reasonable to expect that systems using conventional
treatment for high turbidity source water (e.g., turbidities in excess of
100 NTU), and which optimize chemical treatment prior to filtration, may
be achieving a 3-log or greater Giardia cyst removal if their filter
effluent is substantially below the 0.5 NIL! turbidity limit. Softening
olants using conventional processes and 2-stage treatment processes may
also achieve a 3-log Giardia cyst removal/inactivation. The high p l C of
softening may result in inactivation of Giardia cysts and viruses which
can be demonstrated according to the protocol outlined In Appendix C.
Appendik N can be used to demonstrate the Giardia cyst removal achieved.
multiple barrier concept.
‘ Literature Indicates that well operated direct filtration plants can
achieve up to a 3-log removal of Glardla cysts and up to a 2-log removal
of viruses (Logsdon, 1987b; Roebeck it al., 1962). Limiting the credit
to 2—loq for Giardia cysts and 1-log for viruses provides a margin of
safety by requiring more disinfection. This is consistent with the
multiple barrier concept.
Research has demonstrated that filter effluent turbidities substantially
lower than 0.5 P ITt ! are needed to obtain effective removals of G iartha
cysts and viruses with low turbidity source waters (Logsdon 1987b; Al-
Ani et al., 1985).
5-6

-------
5.3.2 Slow Sand Filtration
For systems using slow sand filtration, the turbidity performance
requirements are:
a. The filtered water turbidity must be less than or equal to
1 NTU in 95 percent of the measurements for each month.
b. At the discretion of the Primacy Agency, a higher filter
effluent turbidity may be allowed for well operated plants
(Section 4.3.5) on a case—by—case basis, if there is no
interference with disinfection and the turbidity level never
exceeds 5 NIL). Noninterference with disinfection could be
assumed if the finished water entering the distribution system
is meeting the coliform MCI and IIPC levels are less than 10/nil
during times of highest turbidity.
c. Filtered water turbidity may not exceed 5 NTU at any time.
Slow sand filtration plants, with appropriate design and operating
conditions and which meet the minimum turbidity performamce criteria can
be considered to be well operated and achieving at least a 2-log removal
of Giardfa cysts and 2-log removal of viruses without disinfection.’
Primacy Agencies may allow systems which believe that they are actually
achieving greater than a 2-log Giardia cyst removal to demonstrate the
actual removal achieved using the protocol outlined In Appendix t i.
5.3.3 Diatomaceous Earth Filtration
For systems using diatomaceous earth filtration, the turbidity
performance criteria are:
a, The filtered water turbidity must be less than or equal to
1 NIL) In 95 percent of the measurements for each month.
b. The turbidity level of representative samples of filtered
water must at no time exceed 5 ifTU.
Dlatcmaceous earth systems, with appropriate design and operating
conditions and which meet the minimum turbidity performance criterion can
• As indicated In Section 4, pilot studies have shown that with proper
nurturimg of the schmutsdecke, operation at a maximum loading rate of
0.2 a/hr will provide optimum removal of Giardia cysts and viruses
(Logsdom, 1987b; Bellamy et al., 1985).
5-7

-------
be considered to be well operated and achlevTng at least 2-log removal of
Giardia cysts and at least 1-log removal of viruses without disinfection.
Systems which believe that they are actually achieving greater than a 2-
log Giardia cyst removal may demonstrate the actual removal achieved using
the protocol outlined in Appendix H.
5.3.4 Other Filtration Technologies
The turbidity performance criteria for filtration technologies other
than those presented above, are the same as for slow sand filtration.
The Gfardia cyst removal achieved by these systems must be demonstrated
to the Primacy Agency. The protocol outlined in Appendix H may be used
as a basis for this demonstration.
Reverse osmosis is a membrane filtration method used to remove
dissolved solids from water supplies. Desalination is a typical use of
the process. Application to potable water treatment is limited to
extremely high quality raw water supplies of low turbidity (1 NTU or
less) 1 or following pretreatment to produce ‘ supply of low turbidity.
The membrane excludes particles larger than 0.001 to 0.0001 urn
range, thereby effectively removing bacteria, Giardia cysts and viruses.
Credit can be given for at least a 3—log Glardla cyst and 4-log virus
removal, with no demonstration. It should be noted that this removal
credit assumes the membranes are in tact with no holes in the membranes
allowing the passage of organisms.
5.4 Disinfection Monitoring Requirements
Each system must continuously monitor the disinfectant residual of
the water as it enters tha distribution system and record the lowest
disinfectant residual each day. If there Is a failure In the continuous
monitoring equipment, the system may substitute grab sample monitoring
every 4 hovrs for up to 5 rking days following the equipment failure.
Systems servIng 3300 people or fewer may take grab samples in lieu of
continuous monitoring at frequencies as follows:
5-8

-------
£vstem Pooulation Sanwiesipay
5O0 1
50 1-1,000 2
1,001 - 2,500 3
2,501 - 3,300 4
The grab samples must be taken at different times during the day,
with the sampling intervals subject to Primacy Agency review and approval.
If the residual concentration falls below 0.2 mg/I 1 the system must take
another sample within 4-hours and notify the Primacy Agency as soon as
possible, but no later than the end of the next business day, even if the
residual is restored to 0.2 mg/I. or greater within 4 hours. If the
residual is not restored to 0.2 mg/I or greater within 4 hours, the system
is in violation of a treatment technique requirement. Each system must
also measure the disinfectant residual in the distribution system at the
ama frequency and locations at which total coliform measurements are made
pursuant to the requirements in the revised Total Coliform Rule (54 FR
27544; June 29, 1989). For systems which use both surface and ground
water sources, the Primacy Agency may allow substitute sampling sites
which are more representative of the treated surface water supply.
5.5 DISINFECTION PERFORMANCE CRITERIA
5.5.1 Minimum Performance Criteria Required by the SWIR
For systems which provide filtration, the disinfection requirements
of the SWTR are:
a. Disinfection must be provided to ensure that the total
treatment processes of the system (Including filtration)
achieves at least a 3—log removal/inactivation of Giardia cyst
and a 4-log removal/inactivation of viruses. The Primacy
Agency must determine what level of disinfection Is required
for each system to meet this criterion.
b. The system must demonstrate by continuous monitoring and
recording that a disinfectant residual In the water entering
the distribution system is never less than 0.2 mg/I for more
than 4 hours. If at any time the residual falls below 0.2
mg/I. for more than 4 hours the system is In violation. The
5-9

-------
system must notify the Primacy Agency whenever the residual
falls below 0.2 mg/I before the end of the next busuiess day.
c. The system must demonstrate detectable disinfectant residuals
or HPC levels of 500 or fewer colonies/ml in at least 9S
percent of the samples from the distribution system each month
for any two consecutive months.
5.5.2 Pecoimnended Performance Criteria
Disinfection must be applied to assure that the overall treatment
provided achieves at least a 3-log removal/inactivation of Giardia cyst
and a 4—log removal /inactivation of viruses. As outlined in Section 5.3,
well operated filter plants achieve at least a 2 to 2.5-log removal of
Giardia cysts and between a 1 to 2-log removal of viruses. EPA therefore
reconnends that the Primacy Agencies adopt additional disinfection perfor-
mance criteria that include:
a. As a minimum, primary disinfection requirements that are
consistent with the overall treatment requirements of the
SWIR, or preferably;
b. Primary disinfection requirements as a function of raw water
quality as outlined in Section 4.4.
Reconrended Minimum Disinfection
The required minimum primary disinfection is the disinfection
needed for the entire treatment process to meet the overall treatment
requirement of 3-log Giardia and 4—log virus removal/inactivation. The
following table provides a suary of the expected minimum level of
treatment perfortance in well operated filter systems and the reconiiended
level of disinfection.
Expected ReconDended Disinfection
Log Removals ( log Inactivations)
F i ltrat i M Glardia Viruses Giardia Viruses
Conventional 2.5 2.0 0.5 2.0
Direct 2.0 1.0 1.0
Slow Sand 2.0 2.0 1.0 2.0
0 t atosaceous
Earth 2.0 1.0 1.0 3.0
5-10

-------
In cases where the system believes that the treatment processes are
achieving greater removals than those listed above, the actual removal
provided by the processes can be demonstrated through the procedures
outlined in Appendix H. However, EPA recoimiends that, despite the
removals demonstrated, systems should provide a minimum of 0.5 log Giardia
cyst inactivation to supplement filtration and maintain a second treatment
barrier for microorganisms.
Recommended Disinfection as a Function of Raw Water Ou pli y
Although the SWIR requires the overall treatment to provide a
minimum of a 3—log Giardia cyst and a 4-log virus removal/inactivation,
it may be appropriate for the Primacy Agency to require greater removals/-
inactivations depending on the degree of contamination in the source water
as presented in Section 4.4. Following is a sumary of the reconrended
overall treatment which should be provided based on an estimate of the
Giardia cyst concentration in the source water:
Allowable daily avg
cyst concentration/lOG L
( geometric meani > 1-10 > 10-100
Giardia cyst Removal/Inactivation 3-log 4-log 5—log
Virus Removal/Inactivation 4—log 5—log 6—log
If a slow sand filtration plant must achieve a 4-log removal/Inacti-
vation of Giardia cysts and a 5—log removal/inactivation of viruses, and
credit for 2-log Giardia cyst and 2-log virus removal by filtration is
granted, disinfection for a 2—log Giardia cyst Inactivation and 3—log
virus inactivation would be needed to meet the overall removal/inacti-
vation. However Primacy Agencies may allow systems which use particle
size analysis outlined in Appendix H to demonstrate greater than a 2-log
Giardla cyst removal to provide less than 2-log Glardia cyst inactivation
through disinfection.
5-11

-------
5.5.3 Disinfection By-Product Considerations
Although the EPA Suggests increased levels of disinfection for
various source water conditions, a utility should not implement such a
change without considering the potential conflict with the requirements
of existing or future disinfection by-product regulations. EPA intends
to promulgate National Primary Drinking Water Regulations to regulate
levels of disinfectants and disinfection by-products when ‘it promulgates
duinfection requirements for ground water systems (anticipated in 19 2).
EPA is concerned that changes required in utilities’ disinfection
practices to meet the recomended inactivations for the SWTR might be
inconsistent with treatment changes needed to comply with the forthcoming
regulations for disinfectants and disinfection by-products. For this
reason. EPA reco ends that Primacy Agencies exercise discretion,
sensitive to potential disinfection by-product concerns, In determining
the level of disinfection needed for filtered systems to meet the overall
treatment requirements specified in the rule or recoimiended based om
source water quality.
Until the promulgation of the disinfection by-product regulation,
EPA reconrends that the Primacy Agency allow more credit for Giardia cyst
and virus removal by filtration than otherwise recoanended if a) the
Primacy Agency determines that a system is not currently at a significant
risk from microbiological contamination at the existing level of
disinfection and b) less stringent interim disinfection conditions are
necessary for the system to modify its disinfection process to optimally
achieve compliance with the SWIR as well as the forthcoming disinfection
by-product regulations. The following paragraphs outline the recomended
disinfection levels for systems meeting the above conditions.
For well-operated conventional filtration plants that meet the
minima turbidity requirements at all times, the Primacy Agency may
consider giving the system credit for 3—log Giardia. cyst removal (in lieu
of the generally recoemended 2.5-log credit). Also, for well—operated
direct filtration plants, the Primacy Agency may consider giving the
system credit for 2.5—log Glardia cyst removal in lieu of the generally
5-12

-------
reconinended 2.0-log credit. EPA reco mnends that these additional credits
be given for conventional or direct filtration only if:
a. The total treatment train achieves 1) at least 99 percent
turbidity removal, or filtered water turbidities are
consistently less than 0.5 NTU, whichever is lower, 7 or 2) a
99.9 percent removal of particles in the size range of 5 to
15 urn is demonstrated as outlined in Appendix M;’ and
b. The level of heterotrophic plate count (HPC) bacteria in the
finished (dlsinfected) water entering the distribution system
is consistently less than 10/mi.
Systems using slow sand filtration or diatomaceous earth filtration
may be given interim credit for up to 3-log Giardia cyst removal if the
system meets the recomended conditions listed above for conventional
systems. Pilot plant studies have demonstrated that these technologies,
when well operated, generally achieve at least 3.0-log removals (USEPA.
1988a).
The EPA believes that interim level of disinfection requirements may
be approi. riate in some cases depending upon source water quality,
reliability of system operation and potential increased health risks from
disinfection by-products. EPA intends to regulate disinfectants and
disinfection by-products in 1992. At this time it will become apparent
how systems with disinfection by-product problems can optimally meet the
disinfection requirements of the SWTR and the disinfection by-products
regulations, concurrently.
For eza le , a system with a raw water turbidity averagIng 20 NTU
aalntalnlng a filtered water turbidity less than 0.2 NTU can be granted
3—log Glardia cyst removal credit with no further demonstration.
‘ In cases where the Primacy Agency has a data base which shows a
correlation between turbidity and Giardia cysts removal, turbidity may
be used in lieu of particle size analysis. Turbidity removal
requirements should be set to assure 99.9 percent Glardia cyst removal.
A correlation between turbidity and Glardia cyst removal was shown in
a study reported by Hendricks et al (1984).
5-13

-------
5.5.4 Recormnended Disinfection System Redundancy
The SWTR does not require a redundant disinfection system for
filtered supplies. However 1 in order to assure the continuous provision
of disinfection to meet the overall removal/inactivation requirements and
to maintain a residual entering the distribution system, EPA recon nends
that redundant disinfection equipment be provided. As contained in the
1987 edition of Ten State Standards , where disinfection is required for
protection of the supply, standby equipment is required. Automatic
switchover should be provided as needed, to assure continuous disinfectant
application.
Recoimiiendations for providing redundant disinfection are outlined
in Section 3.2.4 and detailed in Appendix I.
5.5.5 Determination of Inactivation by Disinfection
The desired level of inactivation can be achieved by disinfection
at any point in the treatment or distribution system prior to the first
customer. Disinfection provided prior to iitration is referred to as
pre-disinfection while disinfection after filtration is referred to as
post-disinfection. As presented In Section 3.2, the inactivation of
aiardia cysts and viruses provided by disinfection are indicated by CT
values.
The SI4TR defines CT as the residual disinfectant concentration(s)
in mg/L multiplied by the contact time(s) in minutes. The contact time
is measured from the point of disinfectant application to the point of
residual measurement or between points of residual measurement. The
inactivation efficiency can be determined by calculating CT at any point
along the process after disinfectant application prior to the first
customer.
A systetmay determine the inactivation efficiency based on one
point of rnidual measurement prior to the first customer, or on a profile
of the residual concentration after the point of disinfectant application.
The residual profile is generated by monitoring the residual at several
points between the point(s) of disinfectant application and the first
customer. The system can then use the method described in Section 3.2 for
S- 14

-------
determining the total inactivation credit. Profiling the residual allows
for credit of significantly higher residuals which may exist before the
water reaches the first customer. Methods for determining various
disinfectant residuals are described in Appendix 0.
In pipelines, the contact time can be assumed equivalent to the
hydraulic detention time and is calculated by dividing the internal volume
of the pipeline by the peak hourly flow rate through the pipeline. n
mixing basins and storage reservoirs, the hydraulic detention time
generally does not represent the actual disinfectant contact time because
of short circuiting. The contact time in such chambers should be
determined by tracer studies or an equivalent demonstration. The time
determined from the tracer study to be used for calculating CT is Ta,. T 0
represents the time that 90 percent of the water (and microorganisms
within the water) will be exposed to disinfection within the disinfectant
contact chamber. Guidance for determining detention time in contact
chambers is provided in Appendix C.
The residual disinfectant concentration should ta measured laily,
during peak hourly flow, for each disinfectant section prior to the first
customer in the distribution system. Unless a system knows from
experience when peak flow will occur, a system can only identify peak
hourly flow after it has occurred. Therefore, EPA suggests that residual
measurements be taken every hour. If it is not practical to take grab
samples each hour, the system may take grab samples during the period peak
flow is expected to occur, or continuous monitors may be used. The
measurements taken during the hour of peak flow can then be used to
determine the CT for each section (CT 4 j. The determination of Cis is
explained in Section 3.2.1.
Although the Inactivation maintained in the system is determined
during peak hourly flow, the disinfectant dosage applied to maintain this
inactivation say not be necessary under lower flow conditions. Under
lower flow conditions, a higher contact time Is generally available and
the CT needed to meet the required inactivation may be met with a lower
residual concentration. Continuing to apply a disinfectant dosage based
on the peak hourly flow say provide more disinfection than Is needed,
5-15

-------
increasing costs and possibly resulting in increased levels of disinfec-
tant by-products. However, the system should also maintain the required
inactivation levels at non-peak hourly flows. The system should therefore
evaluate the dose needed to provide the CT necessary for maintaining the
required inactivation under different flow conditions and set the dosage
accordingly. The following example provides guidelines for determining
flow ranges and disinfection levels to maintain the required disinfection.
Examole
A 20-mgd direct filtration plant applying free chlorine as a
disinfectant has a contact time of 27.5 minutes under peak flow condi-
tions. As noted in Section 5.3, well-operated direct filtration plants
achieve 2-Jog Giardiacyst removal and 1-log virus removal. Therefore,
disinfection for 1—log Giardia cyst inactivation and 3—log virus
inactivation is recoirrnended. The pH and temperature of the water are 7
and 5 C, respectively. Using Table E-2, a CT of 55 Is required to achieve
1-log Giardia cyst inactivation at a residual of 2 mg/L. This level of
treatment is more than adequate for 3-log inactivation of viruses
requiring a CT of 6, as indicated in Table E-7. However, under low flow
conditions the available contact time is longer, and lower residuals are
needed to provide the same level of inactivation. Based on the calculated
contact time under various flow rates and the CT values in Table E-2,
adequate disinfection would be provided by maintaining the following
chlorine residuals for the Indicated flows:
CT9O
Contact (mg/L.-m ln) Free Chlorine
Flow (MGO) the (mm) Required Residual (malL )
20 27.5 55 2.0
15 36 52.5 1.5
10 54 50 1.0
5 108 47 0.5
CT 90 corresponds to a 1-log Inactivation. If a different level of
inactivation were needed, CT values for that Inactivation would be read
from the tables corresponding to the pH and t erature of the water.
5-16

-------
— Section 3.2.2 lists the percent inactivations corresponding
to log inactivations, i.e., 0.5-log equals 68 percent
requiring CT 5 3 .
— In cases where the residual, pH or temperature of the water
is an intermediate value not reported in the tables, linear
(straight-line) interpolation may be used.
— , For example, in the above listing, 0.S mg /L residuals are not
included in the Appendix E tables. The CT value was
determined by interpolating between the mg/t value of 46
mg/L—nnn and the 0.5 mg / I. value of 4.8 mg/I—m m.
— CT values for intermediate pH and temperature values may also
be interpolated; or
- The CT values for the higher pH or lower temperature listed
in the table may be used instead of interpolation.
- CT 99 tables in the SWTR can be used to calculate the CT
required to achieve any log inactivation by:
log inactivation
CTrequired a required x CT 99
3M log
The variation in CT required with respect to the residual for
chlorine makes it impractical for the utility to continually change the
disinfectant dose as the flow changes. Therefore, EPA suggests that the
flow variation at the utility be divided into ranges and the residual
needed at the higher flow of the range be maintained for all flows within
the range to assure adequate disinfection. The following flow ranges and
residuals at the given pH and te perature are suggested for this plant:
Free Chlorine
Flow Range ( l CD ) Residual (mg /I. )
5-10 1.0
10- 15 1.5
15-20 2.0
In this way 4 the utility is assuring the provision of the required
disinfection while minimizing the disinfectant costs and possibly lowering
disinfection by-products.
5—1 1

-------
Although these residuals will meet the required CT. maintaining a
residual in the distribution system must also be considered. if there is
no other point of disinfection prior to the distribution system, the
residual for disinfection must be maintained at a level which will also
provide a residual throughout the distribution system. The complete range
of flows occurring at the plant should be evaluated for determining the
required residual. The utilities may establish the residual needs for as
many flow ranges as is practical.
The Primacy Agency should make periodic checks to assure that the
utility is maintaining adequate disinfection at both peak and non-peak
flow conditions.
In contrast to this close control of disinfectant addition and CT
monitoring, for filtered systems which have long detention times and
regularly exceed the CT requirements for the inactivation needed, it may
be unnecessary for the system to calculate CTs each day of operation.
Unlike unfiltered systems where Cis must be calculated each day, for
filtered systems, monitoring the residual at the end of the contact time
may be sufficient to indicate that the required disinfection is provided.
However, this results in much higher CTs in the sucrer than is needed,
which adds to costs and possibly unnecessary Increased production of
disinfection by—products. The following example outlines one scenario for
which this would apply.
Examole
A utility disinfects with chlorine ahead of a reservoir prior to
direct filtration. The Primacy Agency say give a well-operated direct
filtration plant credit for 2-log Glardia cyst removal and 1-log virus
removal. Therefore, 1-log Glardia cyst and 3—log virus inactivation
through disinfection is needed. For free chlorine, the CTs for 1-log
Giardia cyst inactivation exceed the Cis for 3-log virus inactivation.
Therefore, fls for Giardia cyst inactivation are the controlling CTs. The
following water quality conditions occur in the reservoir during the year:
pH 7 —7 .5
Temperature ( C) 5 a 20
Chlorine residual (mg/I) 0.2 — 0.8
5-18

-------
The required CT for chlorine increases with:
- increasing residual,
• increasing pH, and
— decreasing temperature
Thus, for a residual of 0.8 mg/I the CT needed for a 1-log Giardia
cyst inactivation is as follows:
CT 90
Temperature (CJ mglL-min
7.5 5 58 (Table E-2)
7 20 18 (Table (-5)
Tracer studies conducted on the reservoir indicated a T 0 of 150
minutes at the system’s maximum flow. For the maximum CT of 58 mg/I-mm
required, the minimum residual needed to meet this requirement is 0.4
ng/I , al.ulated as:
58 mg/L-min 0.4 mg/I
150 mm
At a residual of 0.4 mg/I, CT 0 is 55 mg/I-mm. Thus, any residual 0.4
mg/I will provide the needed disinfection throughout the year and the
Primacy Agency may require the system to report only the residual
maintained, reducing the effort needed to determine effective disinfec-
tion. Maintaining this residual In the sumer, however, provides much
higher CTs than needed, possibly resulting In unnecessary costs and
increased disinfection by-products.
Meeting the Recoemended Inactivation Using Free Chlorine
As previously indicated in Section 3.2.1, the effectiveness of free
chlorine as a disinfectant Is Influenced by both the temperature and pH
of the water and by the concentration of chlorine. The inactivation of
Giardia cysts by free chlorine at various temperatures and pHs are
presented In Appendix £ (Table £4 through Table £6). The CT values for
the inactivation of viruses by free chlorine are presented in Table (-7.
5-19

-------
To determine whether a system is meeting these nactivat’,ons, the
free chlorine residual 1 pM and temperature must be measured, at one point
or several points prior to the first customer, where contact time(s) is
measured. The contact time should be determined from the point of
application of the disinfectant to the point(s) where the residual is
measured for determining CTs prior to the first customer. The Cis
actually achieved in the system should then be compared to the values n
the table for the pM and temperature of the water at the point(s) of
residual measurement. Guidance on calculating the CT for chlorine is
presented in Section 3.2.1.
Meeting the Recon nended Inactivation Using Chlorine Dioxide
CT values for the inactivation of Giardia cysts by chlorine dioxide
are presented in Table E-8 and the CT values for the inactivation of
viruses are presented in Table E-9. As shown in Tables E-8 and E-9. the
only parameter affecting the CT requirements for -chlorine dioxide is
temperature. However, the disinfection efficiency of chlorine dioxide may
be significantly increased at higher pHs. Since the CT values in Tables
E-8 and E-9 were based on data at pH 7 and 6, respectIvely, and chlorine
dioxide appears to be more effective at higher pl4s, systems with high pHs
may wish to demonstrate that CT values lower than those presented in
Tables E-8 and E may achieve the desired level of inactivation.
Chlorine dioxide residuals are short-lived. Therefore, sampling and
residual analysis at various points in the treatment process downstream
of the point of application may be necessary to establish the last point
at which a residual Is present. Subsequent sampling and residual analyses
conducted upstream of this point can be used to determine the CT credit
by using the demonstrated detention time between the point of application
and the s lIng location. Methods for calculating CT values are
presented In SectIon 3.2. Systems using chlorine dioxide may conduct
pilot studl.s to de nstrate effective disinfection in lieu of calculating
CT, or for determining that lower CT values than those in Appendix E are
appropriate. Guidelines for conducting these studies are presented in
Appendix G.
5-20

-------
Meeting the Recon nended Inactivation using Ozone
CT values for the inactivation of Giardia cysts by ozone are
presented in Table E-1O for various temperatures and inactivation rates.
As indicated in this table, the CIs required for inactivation with ozone
are substantially lower than those required for free chlorine. This
reflects the fact that ozone is a more powerful disinfectant. The CT
requirements for inactivation of viruses using ozone are presented in
Table E-11. Because of the reactivity of ozone, it is unlikely that a
residual will exist for more than a few minutes. As a result, the
application of a persistent disinfectant such as chlorine or chloramines
is needed to maintain the required disinfectant residual in the distribu-
tion system. Guidance for calculating CT values for ozone are presented
in Section 3.2.1. In lieu of calculating the CT for an ozone contactor
or to demonstrate that lower Cis are effective, the disinfection
efficiency can be demonstrated through pilot studies as presented in
Appendix G.
Meeting the Recor riended Inactivation Recuire ncnt5 using Chioramines
CT values for the inactivation of Giardia cysts by chloramines are
presented in Table E-12. The high CT values associated with the use of
chioramines may be unachievable for some systems. In these cases 4
chlorine, ozone, or chlorine dioxide should be used for primary disinfec-
tion, and chiorainines for residual disinfection, as necessary. Table E—
13 presents CT values for the Inactivation of viruses with chloramiries.
This table is only applicable for indicating virus inactivation efficien-
cies if chlorine Is added prior to anuonia. Systems which add aninonia
prior to chlorine or anmonia and chlorine concurrently, can determine
viral inactivation efficiencies using the protocol given in Appendix G.
For system applying chioramines to meet the virus inactivation require-
ments, EPA rec ends that they also monitor for HPC in the finished
water, as presented in Section 5.6. Systems also may demonstrate
effective disinfection with chioramines in lieu of calculating CT, or to
determine that lower CT values than those Indicated in Appendix E are
appropriate. The protocols outlined in Appendix G can be used for this
demonstration. Further guidance on chloramlnes Is given in Section 3.2.1.
5-21

-------
Meeting the Inactivation Requirement
Using Ultraviolet (Liv) Radiation
Ultraviolet radiation is a method of disinfection which can be
applied to meet the virus inactivation requirements of the SWTR.
UV disinfectant dose, expressed in terms of Liv intensity and
exposure time/unit area (mW_sec/cmZ) incorporates the elements of the CT
concept and therefore can be considered as analogous or equivalent to a
CT value. Liv disinfection usually employs comercially available units
designed to deliver doses of 25 to 35 mW-sec/cm 2 . The dose can be
increased by reducing water flow rate and/or by adding additional units
in series. Liv disinfection efficiency differs from that of chemical
disinfectants in that it is not affected by water temperature. LIV
radiation does not effectively penetrate solids and is absorbed by certain
dissolved substances. Therefore, turbidity and other water quality
factors are important determinants of ( IV disinfection efficiency, and UV
should be applied after turbidity removal.
CT values for the inactivation of Giardia cysts by ( IV are not
included in Appendix E. The results of two studies (Rice and Hoff, 1981;
Carison 1985) indicate that Giardla cysts are extremely resistant
to inactivation by UV with doses greater than 60 mW-sec/cm causing less
than 80% inactivatIon. Because UV appears to be very Ineffective for
Giardia cyst inactivation and in the absence of sufficient data showing
the doses needed to inactIvate 0.5 to 3.0 logs of cysts, (IV must be used
in combination with other disinfectants to provide evidence of effective
cyst Inactivation.
CT values for the inactivation of viruses by UV are presented in
Table E-14. Units used for UV disinfection should be equipped with fail-
safe devices that will provide automatic shutdown of water flow If L IV dose
decreases to levels lower than those specified In Table (-14.
Meeting tire Inactivation Recuirement Using Alternate Olsinfectants
For syste. using disinfectants other than chlorine, chioramines
chlorine dioxide, or ozone, the effectiveness of the disinfectant can be
demonstrated using the protocol contained In Appendix G. The protocol In
Appendix G.3 for batch testing should be followed for any disinfectant
which can be prepared in an aqueous solution and will be stable throughout
5-22

-------
the testing. For disinfectants which are not stable, the pilot study
protocol outlined in Appendix G.4 should be followed.
Examoles for Determining the Disinfection to be Provided
1) Reco nended O.S-log Giardia. 2 -log Virus Inpct vation
A coiruriun ty of 70,000 uses a river as its drinking water source.
Ozonation prior to a conventional treatment plant is used to treat the
water. The source has a protected watershed with limited human acti’dty
and no sewage discharge. The river water has the following water quahty
characteristics:
Turbidity 10 - 200 NTU
Total estimated Giardia cyst level <1(100 /1
pH 70 — 7.5
Temperature 5 - 15
The treatment plant has a design capacity of 15 agd and treats an
average flow of 10 gd. A three chamber ozone contactor precedes the
rapid mix. Alum and polymer are added as a coagulant and coagulant aid,
respectively. The finished water turbidity at the plant is ma ritained
within the range of 0.1 to 0.2 NTU. Chioramines are applied after the
filters, but prior to the clearwells, to maintain a residual entering and
throughout the distribution system.
Based on the raw water quality and source water protection, an
overall 3—log G ardia cyst and 4—log virus removal/inactivation is
appropriate for this water source. However, as noted In SectIon 5.3,
Primacy Agencies may credit well operated conventional filtration plants
with 2.5-log Glardla cyst removal and 2-log virus removal. Therefore,
disinfection for 0.5-log Glardla cysts and 2-log viruses is recoimnended
to meet the overall treatment requirements of the SWTR.
On the day of this example calculation, the peak hourly flow rate
of the pLant was 13 gd. The contact time of the ozone basin, T 0
determined from tracer study data Is 6 mInutes for this flow. The water
had a pH of 7 and a t erature of 5 C on the day of the calculation. For
5-23

-------
ozone under these conditions of pH and temperature, the following CTs are
needed for the required inactivation (Tables E-10 , f-il):
O.5-lo iardia 2-log virus
CT 0.3 0.6
The CT valtres indicate that viruses are the controlling parameter for
disinfection and the overall inactivation provided will be calculated
based on viruses. The overall virus inactivation provided by the ozone
contactor is determined as follows:
Average
Residual T CT , 1 CT CT /CT, 9
Chamber C (malL) ( minutes) ( ma/I) ( malL-nun. )
1 0.1 2 0.2 0.9 0.22
2 0.2 2 0.4 0.9 0.44
3 0.2 2 0.4 0.9 0.44
The sum of CTCIIC/CT 99 is 1.1. This corresponds to more than a 3-log
virus inactivation determined as 3 X CTCaICICT9, • 3 X 1.1 a 3.3—log.
Therefore, the system exceeds the recomoended inactivation.
2) Recommended 1-log Giardia Cyst. 2-lop Virus Inactivation
A 2 MGD slow sand filtration plant treating reservoir water, fed by
mountain streams with no nearby wastewater discharges, provides drinking
water for a coulnunity of 8,000 people. The water quality at the intake
has the following water quality characteristics:
Turbidity 5 - 10 NTU
Total coliforms Not measured
Total estimated Giardla cyst level <1/100 L
pH 6.5 — 7.5
Te erature 5 - 15 C
The filtered water turbidity ranges from 0.6 • 0.8 N1U. Considering
the source water quality and plant performance, an overall 3-log Giardia
cyst and 4-log virus removal/inactivation is considered sufficient for
this system. As noted in Section 5.3, the Primacy Agency may credit slow
sand plants with 2-log Glardia cyst and 2-log virus removal. Therefore
5-24

-------
disinfection for 1—log Giardia cyst and 2-log virus inactivation is
reconrended for the system to meet the overall treatment requirements.
Chlorine is added prior to the clearwells to provide disinfection.
The clearwefls have a capacity of 80,000 gallons. A one mile, 16-inch
transmusion main transports the water from the treatnent plant to the
first customer. The inactivation provided is determined iaily for the
peak hourly flow conditions. Tracer studies have been Conducted to
determine the T 0 for the clearwells for different flow rates. For the
purposes of calculating the inactivation the system is divided into two
sections.
Section 1 - clearwell
Section 2 - transmission main
The flowrate at peak hourly flow from the clearwefl was 1.5 mgd on
the day of this example. At this flowrete, the of the clearwell is 67
minutes, as determined from the results of the tracer studies. At this
flowrate, water travels through the transmission main at 99 ft/mm. The
data for the calculation of the inactivation is as follow
Section 1 Section 2
length of pipe (ft) 0 5280
contact time (loin)
pipe 0 53
basin 67 0
total 67 53
disinfectant chlorine chlorine
residual (mg/L) 1.0 0.6
temperature C 5 5
pH 7.5 7.5
For free chlorine 1 a 1—log Giardia cyst Inactivation provides greater than
a 4-log virus Inactivation; therefore, Glardla cyst Inactivation is the
controlling p Pa.eter. and the inactivation provided Is determined based
on Glardla cysts. The calculation Is as follows:
SectIon 1 — Chlorine
CT 111 . 1.0 g/L x 67 .lnutes • 67 ag/I-mm
From Table E-2, at a te erature of 5 C and a pH of 7.5. CT 99 IS
179 mg/I-aim
5-25

-------
CT fCT, 9 , = 51 malL-n m 0.37
179 mg/L-min
SectIon 2 - Chlorine
0.6 mg/L x 53 minutes 32 mg/L-min
From Table E-2, at a temperature of 5 C and a pH of 7.5, C I is
171 mg/L-min
CT IC/CT 9 g 32 mo/L-min 0.19
171 mg/L-min
The sum of CT aI /CT 9 g is equal to 0.56. This s equivalent to a 1. 7 -log
Giardia cyst inactivation determined as 3-log x CT ,, /CT 99 3 x 0.56
1.7-logs. Therefore, the system exceeds the disinfection recoamended to
meet the overall treatment requirements.
3) Reconr ended 2-log Giardia Cyst. 4-log Virus Inactivation
A co runIty of 30,000 people uses a reservoir treated by direct
filtration for Its water supply. The reservoir is fed by a river which
receives the discharge from a wastewater treatment plant 10 miles upstream
of the reservoir. The reservoir water quality is as follows:
Turbidity 5 - 15 NTU
Total coliforms 100 - 1000/100 ml
Total estimated Giardia cyst level 5/100 1
pH 6-7
Temperature 5 - 15 C
Based on the source water quality, an overall removal/thactivation
of 4-log Giardla cyst and 5-log virus Is reco ended as outlined in
Section 4.4.
The source water flows by gravity to a 3 MG storage reservoir prior
to pumping to the water treatment plant. Chiorasthes are produced by
first addlag cPflorina then a on1a to the water within the Inlet of the
storage reservoir. Chlorine dioxide Is added to the filtered water prior
to the clearwells. Chlorailnes are applied after the clearwells to
maintain a residual In the distribution system. The system design flow
is 8 mgd with an average flow of 5 mgd. For the calculation of the
overall Inactivation, the system is divided into 2 sectIons.
5-26

-------
Section 1 — the storage reservoir and the transmission to the
treatment plant
Section 2 - the clearwells
The overall inactivation for the system is computed daily at the
peak hourly flow conditions. The pH, temperature, and disinfectant
residual is measured at the end of each section prior to the next point
of disinfectant application and the first customer. The flow is measured
in the transmission maIn entering the plant and exiting the clearwells.
On the day of this example calculation, the peak hourly flow was 6 mgd in
the transmission mains entering and lealdng the pLant. If the flowrates
were different, the TL corresponding to the respective flowrate would be
used in the calculation. Guidance for determining CTs when flowrates vary
within a system is given in Section 32. The water velocity through the
20-inch transmission main is 256 ft/mm at a flow of 6 ingd. Tracer
studies were conducted on the storage reservoir and clearwefls. As
determined from the testing the detention times 1 T 10 1 of the basins at a
f low of 6 mgd are 380 and 130 minutes for the storage reservoir and
clearwells, respectively. The data for the calculation of inactivation
is as follows:
Section 1 Section 2
length of pipe (ft) 4500 0
contact time (mm)
pipe 18 0
basin 380 130
total 398 130
disinfectant chioramines chlorine dioxide
residual (mg/I) 1.5 0.2
temperature C 5 5
pH 7 1
For acb o? the disinfectants used, the following CTs are needed for
2-log Glardla and 4-log virus Inactivation for the pH and t erature
conditions of the system.
5-27

-------
CT for 2-log CT for 4-log
__ Giard ia Virui
chioramines 1430 1988
chlorine dioxide i.i 33 .4
The CT required for the virus inactivation is higher than that
needed for Gfardia Inactivation for each of the dislnfectants. Since the
viruses are the controlling parameter, the inactivation calculation will
be based on the viruses. The calculation is as follows:
Section 1 - Chloramines
a 1.5 mg/I * 398 minutes • 597 mg/I -mm
From Table E-13, at a temperature of S C and a pH of 7, CT 99 is
1988 mg/L-min
CTC .pc/CT 99 • 597 mgJLiiftn a 0.3
1988 mg/I-mn
Section 2 - Chlorine Dioxide
- 0.2 mg/I x 130 minutes • 26 mg/I-m m
From Table E-9 at a temperature of 5 C and a pH of 7, CT 999 , is
33.4 mg/I-mm
• _ 26 mg/L-nñn • 0.78
33.4 mg/I-mm
The sum of CT 1 /CT 99 is equal to 1.08, which is equivalent to a 4.3-log
inactivation of viruses, determined as follows:
x • 4-log x creale a 4 1.08 • 4.3-logs
CT, 9 g
Therefore, the systme provides sufficient disinfection to meet the overall
recoaended treatment performance.
5-28

-------
5.6 Other Considerations
Monitoring for heterotrophic plate count (HPC) bacteria is not
required under the SWIR. However, such monitoring may provide a good
operational tool for:
— Measuring microbial breakthrough
-• Evaluating process modifications
- Detecting loss of water main integrity
- Detecting bacterial regrowth conditions within the distribu-
tion system
- Determining interference with the coliform measurements (AWWA,
1987)
Therefore, EPA recomends rotitine monitoring for HPC In the plant
effluent and within the distribution system whenever the analytical
capability is available in-house or nearby. Systems which do not have
this capability should consider using a semi—quantitative bacterial water
sampler kit, although this is not acceptable for compliance monitoring.
As discussed in the preamble to the SWIR, EPA believes that it is
inappropriate to Include HPC as a treatment performance criterion in the
rule since small systems would not have in—house analytical capability to
conduct the measurement, and they would need to send the samples to a
private laboratory. Unless the analysis Is conducted rapidly 1 HPC may
multiply and the results may not be representative.
EPA reco ends an HPC level of less than 10/mi In the finished water
entering the distribution system and levels of less than 500/mI throughout
the distribution system.
Legionefl is another organism which is not included as a treatment
performance crtterion. Inactivation Information on Leglonella Is limited.
EPA believes that treatment which co iies with the SWTR will remove
and/or Inactivate substantial levels of Legionella which might occur In
source waters, thereby reducing chances that Legionella will be trans .
ported through the system and reducing the possibility that growth sight
occur in the distribution system or hot water systems within homes and
Institutions. Since Legionella are similar in site to coliform organisms
s-zg

-------
removals by filtration should be similar to those reported for total
coliforms. In addition, the available disinfection information indicates
that the C I requirements for inactivation of Legionella are lower than
those required for the inactivation of Giardia cysts. EPA recognizes,
that regardless of the treatment provided, some Legionella may enter
plumbing and air conditioning systems and subsequently multiply (Muraca
et al. 1986). EPA believes that these concerns are best addressed
through guidance contained in Appendix B.
5-30

-------
6. REPORTING
6.1 ReportIng Requirements for Public Water Systems
Not Providing Filtration
The SWTR requires unfiltered systems to prepare monthly reports for
the Primacy Agency to determine compliance with the requirements for:
- source water fecal and/or total coliform levels
— source water turbidity levels
— disinfection level
— disinfectant residual entering the distribution system
disinfectant residuals throughout the distribution system.
The monthly reports must be prepared and submitted to the Primacy
Agency w th1n 10 days after the end of the month. The utility must
maintain a daily or monthly data log used to prepare the monthly reports.
Tables 6-1 through 6-5 are examples of daily data sheets which the
utilities may find useful for logging the data needed to prepare reports
for the Primacy Agency.
Table 6-6 presents a concise format which can be used by the system
for the monthly reports to the Primacy Agency. Tables 6-3 and 6-4 must
also be submitted with the monthly report. After the initIal 12 months
of reporting, the Primacy Agency may remove the requirement for reporting
the information contained In Table 6-3 If ft is satisfied that the system
is computing compliance with the CT requirements correctly. The
ind ividual sample results sumearized in the monthly reports should be kept
on file at the utility for a ainlmu* of 5 years.
In addition to the monthly reporting requirements for source water
quality conditions and disinfection Information, systems with unfiltered
supplies are also required to submit annual reports for the watershed
control progr and the on-site inspection, withIn 10 days after the end
of the federal fiscal year.
The Primacy. Agency will review the reports to determine whether the
system Is In c liance. A possible report format for the watershed
control program Is:
6-1

-------
1. Suniiiarize all activities in the watershed(s) for the previous
year.
2. Identify activities or situations of actual and potential
concern in the watershed(s).
3. Describe how the utility is proceeding to address activities
creating potential health concerns.
EPA reconvnends that the Primacy Agency submits the annual watershed
reports to the State Water Quality Managers. The reports will be useful
in updating statewide assessments and management programs.
The SWTR requires each system to provide the Primacy Agency with a
report of the on-site inspection unless the Inspection is conducted by the
Primacy Agency. EPA suggests that:
1. A report of the inspection containing the findings, suggested
improvements and dates by which to complete improvements is
to be prepared following the Initial system review. When and
how system has resolved problems Identified in the previous
report should also be included.
2. To lessen the burden on utilities, a report containing results
of the general survey should be submitted in subsequent years.
In addition to these reporting requirements, the SWTR requires that
the reporting requirements of the Total Trihalomethane Regulation and the
Coliform Rule also be met.
Records of waterborne disease outbreaks also must be maintained.
In the event of a waterborne disease outbreak, as defined In part 141.2
of the SWTR, the Primacy Agency must be notified by the end of the next
business day.
The report of the outbreak should contain:
1. Date of occurrence
2. Type of Illness
3. Ni er of cases
4. System conditions at the time of the outbreak, Including
disinfectant residuals, pH, temperature, turbidity, and
bacteriological results.
The records of an outbreak should be maintained permanently or until
filtration is Installed.
6-2

-------
6.2 Reporting Requirements for Public Water Systems Using Filtration
The SWTR requires filtered water systems to submit monthly reports
to the Primacy Agency for determination of compliance with the require-
ments fort
- treated water turbidity
- disinfectant residual entering the distribution system
— disinfectant residuals throughout the distribution system
Tables 6-7 and 6-8 present a format which the utility can use as a daily
data log and to submit monthly reports to the Primacy Agency.
Recommended Reoortino Not Required by the SWTR
The Primacy Agency may also want filtered water systems to report
some information associated with recoimnendations made in this manual which
are not requirements of the SWTR. EPA reco ends that filtered water
systems:
1. Report the log inactivation of Giardia Cysts and viruses,
required by the Primacy Agency.
2. Report point of application for all disinfectants used.
3. Report the daily CT(S) used to calculate the log inactivation
of Giardia cysts and viruses.
4. If more than one disinfectant is used, report the Cl(s) and
inactivation(s) achieved for each disinfectant and the total
percent inactivation achieved.
5. Ilote any difference between the measured CT(S) and the CT
required to meet the overall minimum treatment performance
requirement specified by the Primacy Agency.
Tables 6.3 and 6-4 can be used to maintain the records necessary for
numbers 2 through 5.
This information can be used to determine the disinfection level
maintained by the syste. to assure that the overall removalflnactlvation
required Is maintained.
6-3

-------
The Primacy Agency may make provisions to minimize the reporting
requirements for systems with reservoirs, large amounts of storage or long
transmission mains which provide a long disinfectant contact time. Since
these systems typically provide inactivation in excess of that needed, the
Primacy Agency may require the system only to report the minimum daily
residual at the end of the disinfectant contact time. The CT maintained
can then be estimated based on this residual and the contact time under
the system design flow, This method of CT determination will eliminate
the need for the system to determine the contact time under maximum flow
conditions each day.
64

-------
TABLE 6.1
SOURCE WATER QUALITY CONOmONS FOR UNFILTERED SYSTEMS
(For ry tm u e ooly)
Syw ITr suoe t PIa
,Ycar PWSID
Turbiduv t rcrci
2
3
I

Date
Coliforrn Meaiurcme,t i
Mujmum Trbithrv
Tutbidity
(NTlfl c r ‘4
No o: Samptci
No oi S.azeplca Mw
ng Specified L mtti
Fed
Toul
Fcd(C 201100 mL)
Tai I (
-------
TABLE 6-2
LONG-TERM SOURCE WATER QUALifY CONDITIONS FOR
UNFILTERED SYSTEMS
(For y em u ooiy)
Syucm/1rc, amcn* P a z
PWSID
Turb r Mca1urrrnLnc
C Idorm Mcij rcm ntr Devi wttt umbc ol
So o Sei oa I So ., Si p1c Meenn; SpecLfleá Lisnau Turbtthcy Tu rDIUV
To aJ 0/IOO mU To I < OOi cO mL) j >5 NTU
I

-------
TABLE 6-3
1.2
CT DETERMINATION FOR UNFfl -TERED SYSTEMS — MONTHLY REPORT TO PRD 4ACY AGENCY
Month — Sy*can/Tr z Plesd
Yc.u — PWSID
Df S uenc o( AppLic zia —
3
3
3
D i au i1 tan
D is&nf nt
4
W*i
C i cenrrinon.
Cont.c Time.
CTciJc
3. S
Terrtp
6
Dare C (mg’Ll
T (mur
( C T)
pH
(dq C)
CT99 9
(CTcaJc CT99 9’
3
4
.3
6
7
8
9
10
L
I I
12
13
14
!
I
I IS
19
L
2$
26
27
28
29
30
_____________
31
Pv 4b
D
Notci.
I To be iadadad the Iy , oet foe m 12 sfte the of rq . 1 itao . Met th tims. the Pnmacy A cy
may ac Ioaet ..,..as th fora.
2. U i. a scpsz tora for .scb d thm.mpIiq us. Eator dia Is a sad p e a. s - i.. aslIm. or C102/3rd
3. Mesauremmot takes m psak boorty Uo .
4. CTcaIc • C (m /L) s T (mm.).
S. Ooly tequgad t( the dimofeataix m tree cbkeies.
6. Froa Tib is 1. 1-I 6, 2.1. sad 3.I.IOCFR 141.744bX3).

-------
TABLE 6-4
FOR UNFILTE
DISiNFECTION INFORMATION
RED SYSTEMS - MONTHLY REPORT TO PRIMACY AGENCY
Sy eieJTeommom Plant
PWSID
Disutic tant Rcsidisij
Poun-or.Eotrv to
S stem cr /L)
(CTalcCT99 9 (ftom labre 6.3)
2
SUM (CTciIc1CT99 9)
3
SUM )CTc&lciCT99 9) CI
(Yes or No)
lit
D si
2nd
fltcctaflt
3rd
—
Secuence
4Th 5th 6th
—
—
I
1
I
-____
-
Notes
N 9 .4by
0g.
i It less thai 0.2 m fL th. 3o m IsvuI and 4u gj of the parted mu* bs r Md. .. • 0.1-3 hn..
2 To dnt mi SUM (CTcak/CT99.9). add (CTcala/C799.9) v. um from the fiM disinfectant mquan ta the Ls&.
3 It SUM (CTe.IcICT99 9) c i • a tntm-’ us vio sc oa has cccansd. sad s yss r’ po mum be .m. d.

-------
TA LE 6-S
DISTRiBUTION SYSTEM D FECTANT RESIDUAL DATA FOR UNFILTERED AND FILTERED SYSTEMS
MONTHLY REPORT TO PRD4ACY AGENCY
onth ______________
Y ..er
Sy e&Trc s P a
PWSID
D. tc ‘ o . I Sitet Where
Dt intcgurn Residu,.1
1o ut Sitee Where no No of Sifls Where
Duanicctut Residuel Dt .infccr.ant Residusi
No of Sites Where
Disinfectant Rcsidual
No of Site. Where
Disinfcctint Residual
was .Ieuured (na)
Measured, but IIPC ‘‘4ut D ecred. no HPC
Not Dcs ted.
Not Measured.
‘
Mcuurcd(ab)
Mcasured(.c)
HPC > SOOInt.1(.4)
HPC >500 rnli(ac)
I,
31
ii
u
7:
st
9i
10
H
J!
13
- j
Is
-
I
I ,
IS
191
20
21
1,
23
24
25
26
27
23
29
30
3 1
Toed
a.
b .
c
4—
•
S
V (C +4 +.y(a4b$ LOD (_ ,._... ,+___+__. ,YL_+___ .) a 100 _%

-------
TABLE 6-6
Source W t Ou&irv Condirions
MONThLY REPORT TO PRIMACY AGENCY FOR
COMPUAjJCE DETERMINATION — UNFILTERED SYSTEMS
Sy c&Tstaemcot Ptant __________________________
PW SfD ________
C .imuktu c numbes ot mo thi lot which results in reported
Fo source water colirerm monitoring of months)
For turbidity monitoring (No o months)
B C i1orm Criteria
F cii TouJ Fec.I(< 20/lOOmL )
Prc iovs 6 month,
Percentage of umplcs < .20/ 100 mL. focal cohuorm,. F • y/ws 100 ___________________
Percentage o(aamplca < 1001100 rnL t aI coliforma. I — a/s a 100 • ____
IsF90%’ Yes _ No _NIA_. sT<90%’ Yes .Plo _N/A —
C
Turbidity Criteria
Mas*minn turbidirw lescj for rcpornng (cuerenI motub ________ STU
Enter the month 20 rnonthi prior to thc rcporiint month or January 1991 (whichever ii (axes )
8qtnning Date Duration Idavi) Date R* o,tcd
Daici ol 5 NTU Escwlsnccs Since Latew Mortb Recorded Above
Disinfection Criteria
A Po in*o1-Entry MLrtimum Disinfectant Re ithuii Cntcria
B
Day
Durazion of Low Le e.1 (bra.)
Date Reported
to Primacy Agency
Diatstbuuoo Sy am Dsauifectar* P i 1 Cr ena
The value of sb. c. d. and. frot T.b(. 6.5, as apecsficd is 40 CFR 141.75 X2XüiXAHE).
V c+d+.i100.
Foapeeviouamo ,V.
C
Dwnfocssoa &cquat Ce i.
Record the d SUM (CT cFCT99 9) foe any SUM (CTc iIcICT99 9) ‘ CI (fiann Tá s 6-4)
It aens eteot s.
Date
SUM (CTCaICICT99 9)
I. Tb. current 6-anoeth esueula avan are acquired to d mua. ‘h bot CCtn IaE n’ith the ifo aICTSI
has bean schiseed. Thean tctale arc ealeuIai t franc: the pn.now 6-nco ccncul the
moatha. and totals (roan the ani1i c i 6 previous receth. .
Moeth —
No of Samples No of Samples Mecting Spcci( e4 Limits
TcuJ(< 00/I00riL
Days the Residual was (02 me /

-------
TAaLE 6-7
T ais
POT muitip&. diiinf. , thi u cs y bs w’spL t for ibe l thathf print or* the d at gios
lydelL if ma than 0.2 m$ L, tM J .it.. . ci the riod mug be e.g. 0.L3 htU.
2 For IyESTh* a $ diti (Utiwi..,., or olo • th eand or usr oo ,
turbidity mcsauremcma may bs bea th oomb e4 affir• e8w J dT1u or pl affleug prier y i the
thgtthig,oc eyitrin The turbidly may i8an b. for mab • piz ism —- - “i for oreb.
3 For coctinuew monitors co aneb $boer pined us I anmp4s.
4 Depending on the f 1trgio. i _ k. _ .lcV employed. th. im or Cf turbidly Lnpl “fig ths (aU iq berth mug he
crjovemional trortmma at di, IUtrtg e .O.5 NW, a ow med t e cc-I NTU. diniomacwus esith fUi mins-l P4TU. The Sons may
specify .keniate performance berth ( c i tinnnl tn or ditcc* t iltig ion. act . t 4 ’$ I NW. lAd IIO med tilzrctxm.
not c c.Cdi n$ 5 NTU. in .bgb m ae the ee at of tuibidity mceme mma memeg them berth mum b. re uided .
3 In rccotthna the number o(wtbidity mas rsmanti e. 4 iflg 5 fl1), the tusbidi y yihge ouId else be . . .J.d. e g . 3-36.62.10 ’
DAILY DATA SHEET FOR FILTERED SYSTEMS
(For .y*cm only)
\ onuh Syacs&Trcuimait Plant
Y 4r Flltraboa TCChcIOLO ,
PWSED________
I
\tinirnun, Oi inicci nt Rci&diiil
t Pornt.oi .Entrv IC
o /L)
2.
— Ma mum Fthceed_W.iet_Ttirbidity
3 4
No o(Turbi4uy
No of Turbidity Mcuureritern. c
Meaniarerneni, Specthed Limit
5
No of Turb.duy
Meuiirrme ni
5 NTU
Ether
I
Combined Ether
Effluent
Clcirwe 1
Emu
Punt
Emecet
4
.
I
tO I
II
2
13
14
15
6
18
9
10
2 1
, .,
23
24
25
26
27
28
29
30
31

-------
TAELE
Month __________
MONTHLY RE.PORT TO PRiMACY AGENCY FOR
COMI’UANCE DETERM1NAT ON - FILTERED SYSTEMS
Sy nsn/Tre m Plant ______________________________________________
Typc of Fil oo
Tuvbidity Lutcct _________
PWS D_____
Tuthtthrv PC IOTr U CC Crc erci
T tai nurr ’er of fJtcred l aIcr twrb 4 ty nccaa ’remcn i ______
8 Toal number of r cw.cer lurbcthry manaixremenu ch i c eu chin or equal io the ipecifi d lim zi
Ia, the t 1rrax,ce :echno ogy employed — ________
C Iho percentage of iurbidixy mcuurencanta m u g the ip cfmd Itm • BJA a DO. / a 100 -
0 Record the dam and turbidity vajuc for .nv meanuremenu cecnethng S NYU If none. cntce ncoc
Date Turbidity. NTU
)mt n(ectmOn Pcrforrmincc CDltcni
A Point.of.Entry Muurnure Duiafecxanx Rcaidual Critena
Detc
Mutimum Dcainiecwmt Rc*adIiIL
at Point of.Eimt y
to Dc ributcae Sy em (m 1L)
Oatc
Minimum Disumfntxaig Reudual
ax Point-of-Entry
to Dignbutioe Sygem rn 1L)
1 Mtnuntim Diaumfnemasu R. ual
•z Posat ot-E ury
Date to Dignbunon Syeem (i*g/L i
1
2
11
12
JL
22
T
- -_____
r_____
- i-
14
iT
zs
_____
i

T_____
- -_____
T
i _____
‘
ir_____
- -_____
____
JL___
! _____
31
Dsntb.Ralualwaa .C02m,./L
.,
DflbO. of Los Loyal (h it)
)ats R a .d Pn y A c
B D *e j*ioe Sydam Dialn(cnta P al Cr
Tb. v.iua of.. b.c, 4. s from T 4. 6.1. a 40CV1 141.73 (bX3X1 .XaX.)
a b a a _____ 4 • . . . a
V. c+4+ . iL .______
Forprcvtou .niootb.V _%
[ Pv sIidby
I D .

-------
7. COMPLIANCE
1.1 Introduction
This section provides guidance on when and how the requirements of
the SWTR wifl go into effect, including determinations made by Primacy
Agencies.
7.2 SYSTEMS USING A SURFACE WATER SOURCE (NOT GROUND WATER
UNDER THE DIRECT INFLUENCE OF SURFACE WATER
The SOWA requires, within 18 months following the promulgation of
a rule 1 that Primacy Agencies promulgate any regulations necessary to
implement that rule. Under 51413, these rules must be at least as
stringent as those required by EPA. Thus, Primacy Agencies must
promulgate regulations which are at least as stringent as the SWTR by
December 30, 1990. By December 30. 1991, each Primacy Agency must
determine which systems will be required to filter. If filtration is
required, it must be installed within 18 months following the determina-
tion or by June 29, 1993, whichever is later. In cases where it is not
feasible for a system to install filtration in this time period, the
Primacy Agency may allow an exemption to extend the time period (see
Section 9).
If a Primacy Agency fails to comply with this schedule for adopting
the criteria and applying them to determine who must filter, systems must
comply with the objectlve’ or self.iinplementing criteria (i.e., the
requirements that are clear on the face of the rule and do not require the
exercise of Primacy Agency discretion). Unfiltered supplies must comply
beginnIng December 30, 1991 and filtered supplies begInning June 29, 1993.
MonIto ing requirements for unfiltered systems must be met beginning
December 30, 1990 unless the Primacy Agency has already determined that
filtration is necessary. This coincides with the Agencys requirement to
promulgate regulations for making filtration decisions by that date under
the SOWA. Primacy Agencies say specify which systems should conduct the
monitoring necessary to demonstrate compliance with the criteria for
avoiding filtration. For some systems where an historical data base
exists, and where it Is apparent that the system would exceed the source
7—1

-------
water quality criteria (or that some other criteria would not be met, such
as an adequate watershed control program), no monitoring may be necessary
for the Primacy Agency to determine that filtration is required. If a
particular system (and/or the Primacy Agency) knows that it cannot meet
the criteria for avoiding filtration, there is no reason to require that
system to conduct the source water monitoring prior to the formal decision
by the Primacy Agency that filtration Is required. This is true because
the only purpose of that monitoring would be to demonstrate whether or not
the criteria to avoid filtration are being met.
In reviewing the data for determining which systems must filter, the
Primacy Agency will have to decide on a case-by—case basis the conditions
which will require filtration. For example, a system may not meet the
specified CT requirements for the first few months of monitoring and
upgrades its disinfection to meet the CT requirements in subsequent
months. In this case, the Primacy Agency could conclude that the system
will be able to meet this criterion for avoiding filtration. The time
periods specified for In the criteria to avoid filtration (e.g., six
months for total coliforms, one year and ten years for turbidity and one
year for CT requirements) do not begin until December 30, 1991 unless the
Primacy Agency specifies an earlier date.
Beginning December 30, 1991 the requirements for avoiding filtration
specified in S14l.11(a) and (b) and the requirements of 5141.71 (c) and
S141.72(a) go into effect unless the Primacy Agency already has determined
that filtration is required. Beginning December 30 , 1991, if a system
fails to meet any one of the criteria for avoiding filtration, even if the
system were meeting all the criteria up to that point 1 it must Install
filtration and cc ly with the requirements for filtered systems includ—
Ing the general requirements In 5141.13 and the disinfection requirements
in 5141.72(b), within 18 months of the failure. Whenever a Primacy Agency
determines that filtration is required, it may specify interim require-
ments for the period prior to installation of filtration treatment.
Following the determination that filtration is required, the system
-must develop a plan to i lement its installation. The plan must include
consideration for the following:
7-2

-------
- Providing uninterrupted water service throughout the
transition period
- Siting for the future facility
- Financing options and opportunities
- Scheduling of design and construction
Systems which are unable to install filtration within the specified time
frame may apply for an exemption to extend the period for installing
filtration.
Table 7-1 sumarizes the requirements for the SWTR for unfiltered
systems noting conditions which require the installation of filtration.
It is important to note that only treatment technique violations trigger
the requirement to install filtration while violations of monitoring,
reporting or analytical requirements do not. The monitoring requirements
for unfiltered supplies are presented in Section 3 and the reporting
requirements are presented in Section 6.
All systems with filtration in place must meet the treatmert
technique requirements specified in S141.73 (filtration criteria) and
5141.72(b) (disinfection criteria), and the monitoring and reporting
requirements specified in S141.74(c) and S141.75(b), respectively,
beginning June 29, 1993. Table 7-2 sumarizes the SWTR requirements for
filtered systems, Including conditions needed for compliance with
treatment requirements. Monitoring requirements for filtered supplies are
enumerated in Section 5 and reporting requirements are presented in
Section 6.
7.3 C l1ance Transition with Current PDWR Turbidity Reoulrements
The current (interim) NPDWR for turbidity under 5141.13 (MCL
requirements) and S141.22 (.onltoring requirements) will apply for
unfiltered systems until December 30, 1991 unless the Primacy Agency
detereines that filtration is required. In cases where filtration Is re-
quired, the Interim NPDWR applies until June 29. 1993 or until filtration
is Installed, whichever Is later. Unfiltered supplies will also be
7-3

-------
1ABU I I
IQUI (NTS ioa ii in;titii IISI(IS
i.quli.d 1 IIII,.,I
Pisiltissit Clitsilsi onhIcfIsa CouPolIpncs I ) 1jIt.piip 2 Pii ac, Atonci
UaIllIsesl S. pllu,
$)I1 H)
•) Zs.ucs W.tie QUality
CssdIil.ss
I) lieu C.Illsia ?I,1O I f(i Siit ( I% St i Iu aonI lp
i .t .t C.ItI.t. iOOIlS l lucid is is. yni 6 Soj ipall
p.pI.tl. s I tilIs,l..
1) i.,lldltp UIU esallsp. uc (SIIU ISIIU .sls Spit Yui
St Sl ,4 III Sv1 5S
d i ,
I) !lle p.eUle
C u llS sup
I I) DScsstsetSss tat C1 1 • daily ii ciISitis. vi llas In .o .lIi Vis
i-lay Liucils pub I I .. Is iS , lii l ii I l r.peiI
e s a l.lsj .u. •
vlrei Is iclivaS isi lii iii .slla (1)
SS1I 7 2(a)) day ps
s II
l.dusdast
I S s lulacl iss c s as stI insist capost
C . assIi asS Is put. Si en liii
($515 P2(s)(i)) ia peclIua
PIsIslaclast 0 2 Fl cu Il assup, sot 0 2 .(I vistaS as I I (0 2 0, 5 5 bv inus$
lasids il syaSass 3)OO to, 4 /l I.; 1 4 hujl ds P (0 2a4/l YSS (ii 0 I .g t
.aI.i1 ij Ii pspui .l ii. 1.1.11 P,i.scy lot as, p1 1 1.1 I D, 4 louis)
apsis. pub 1 II2 uI.Iasn.o St las
($ 14 1 fl(I)(i)) ussinil sad
.up;.dt eSa lI.
(Si) Ois5slstla 5 Issidusi Istana ss Sacs diliclabS. vl iI uIi.s .o Illy Ill
a Is PialtibuIlsi tualdial a, los I It. • In 9S% . 5 uap,os Sa,lug. is
SpaS.. (Sill 12(.)(4)) HPC 100/al seas, basil as sont bly u .S cauud Ip hut
popi.iiIIaa. up s la pt., I., i.utp I. louisa • ll il
pissed by 31.1. in, 5., tin lisilavOl
situ sue

-------
JABLI 1 I
lLQJIIINL Is loB uiI tji to systlus (t.nhi ed)
RI uéiud I
Crilitisi Iiiiit.ilna •fl• s N I,Il (&Ilpn
7) VaIsiiIs Cimlill • ••S1I SCUVIIISI IR Il$slI.ti, I •nmva l
USII (S S4 •I.31 •
l.ISi.se.l S
Pi I ac,
3) Ou sIIa I.ipscl$sa sh s i(
•iigi I ØfS(l H 505 1$
dIs uI.cI ls• dsIi, n,4 Ip
Ptt tp A smcj
4) IstsiIuss 01. 1.1 . is sulbieds public IsilI b Is •ulb,.sb sulOflO sill Sss$ bu ,nin
•scsidsd will euiisal cufismi c.aligui dsj
c..Ii ,us. l,. s slila .id s.uics
SRI UUIcS
S) ).I.I Celilsis Isle ji •.SIII VI lit tiiqii. Icp .5. 1 ciII .tl.i I ctIl.iIis I., )I sonlilt
s p st.. . . 1 1.4 hill •• .sc.l .5. 1 1 ii 17 esaisculi,. ispost
(10 sa I.1/.i. pspul .tiI1 mIIa sallil
15 0 p•slsIe. sties ii i ii
lit s,sl i tush ii a
1.11.1 L 1 1 s ieflulutp a
p 1 1 1 1 . 5 s.iut. US$11
I) hid Tsilsllb**S S 10 1I pu.;luilp cities is. PsasI
Ss$els l lea I ii spala a •aau.l 1 .1 5 1g.
sit,
‘ID . 000
‘W I
I I.. IliaCl isulhs a a lusls.aI I•clnI .i .lsI.Ii.s
2 hush I. IsaiaH I tlIsall e. stillS II . 5liII sIt i lisisis IS mall usIlIl*i d iuppip cs,istte sesuils is u 11* 1 1.5.1 lacbsiique lø$al,o5
3 i i Iei.I asasp.p.i stills ii Ispu SI vIsISU SS ass salt suits sill bill ci Ip il ,siI wil l4. IS laps 0$ viQISlISS
4 P 1 . 1 s t lii s Is shield sc 7 ci U t e assc ullVl sinus II lie is Iuacp Ag.ncp l.*.t.I .uI eu ,Iala%ien ti is CHIlI ip ututusl bAd u ps.diclibtI
ti cu m*tU(S1
S PLs..tp A .atp sap Islicala. elsilal adalulls IIH.h.s$io. ii pi*iidcd

-------
TABLE 1 2
RIQUIRENENT5 FOR FILTERED SYSTEM
Not l us h un
isu olia mn i Ctllitlsn Mon i lo e Sn o cpn ip l u i n cs 1 Pisinace Agency Puri hi_c 2 5
FllIsisd Soppliss (SIll 13)
u) Ciussn llsus l Sr DIrsol 0 5 NYU conlinuous ci 95% monthly month ly Ye s
Fl ll est lss (up Is I NTU) lrst/4 bet ssenples ( MC I eepofl
none 5 5 NYU
h) Slu. osod filtration I NYU continuous ye 95% monthly monthly Yes
(up Is S nsb/l bo 1 snupiss C MCI espoel
(one/dsp) ’ nons 5 S NiB
Ohilsmarssss Earth I NTIS contInuous or 9 5%sonu lly monli.Iy Yes
Fill nsilso peat/I his ssmpiss C I NYU upo n
non, S UTU
1) Other TechnologIes I NTIS op continuous or 95% mon lh lp monlhly Yes
(to S NTU) 0 nah/I hrp 4 samples C EL report
(ens/dsp)’ ‘ none S NYU

-------
3*8 (1 1-2
R(Qul*(N [ l5 s bR F)LILRID SYSTEI (Canh.oued)
hot it ci i sut
Cf!tII .n __________ Pi InII O *ieIflp ______
DislmlutIio so fliIsrs
Soppilso (5th 72(e))
I) Sup ism.iil tlIlo.IIus so Sp,tiI ,sd
to •sst Ovitill
bouata.nt
2 1) Olilitsetsat lisidial 2 u IL i onhlnvo ii i. not ( 0 2 ai /L liii Ye
lots ’ is, Spite. o oIimo C 3300 to, I bis Dussniss
popul.l son-geib
o impt U S
31) Dboiat.ctuit l.at e,s) itittib l. amp is fbi C UCL in ipamihi
Is Olilollutigo Spots. rsIiduaJ,1r HPC tacit ion & ‘ s% at monibip repast
Ii.qu.nc y scuplss toe 2
biouit an con scuIivs monhli
populat ion
appto,sd by
Stats
3 ls.-o tliseI Issalli In S Ue.Imsot t.ctniqus siai.t,on
2 ii toast nsapspso itbhn 11 dips ii uiotillon sod .eih nolic, ilti bill or bp Itaitib silbiS 45 days of vioPiiiOti
3 Priasey *$.acy asp dsIsraun. sh.lt.r idiqauts dtntnisct IDfl Ii provbdud
4 Ii Prlaacp Agonap eusecloss dtoua.tIDn

-------
subject to the turbidity monitoring requirements of 5141.74(b)(z)
beginning December 30. 1990 coincidently with the interim requirements.
Beginning June 29, 1993, the turbidity performance criteria for filtered
systems (5141.73), and the monitoring requirements under 5141.74 will
apply.
7.4 Systems Using a Ground Water Source
Under the Direct Influence of Surface Water
Part of the Primacy Agency ’s program revisions to adopt the SWIR
must include procedures for determining, for each system in the Primacy
Agency served by a ground water source, whether that source is under the
direct influence of surface water. By June 29, 1994 and June 29. iggg.
each Primacy Agency must determine which coimiunity and non-comunity
public water supplies, respectively, use ground water which is under the
direct influence of surface water. EPA recoumends that these determina-
tions be made in conjunction with related activities required by other
regulations (e.g., sanitary surveys pursuant to the final coliform rule,
vulnerability assessments pursuant to the vol atile organic chemicals rule,
the forthcoming disinfection requirements for ground water systems). In
addition, EPA-approved wellhead protection programs required under the
Safe Drinking Water Act Section 1428 may contain methods and criteria for
determing zones of contribution, assessments of potential contamination,
and management of sources of contamination. These programs may be used
as a partial basis for the vulnerability assessment and for making the
determi nation of (a) whether a system is under the direct influence of
surface water and (b) if direct influence is determined, whether there is
adequate watershed control to avoid filtration. Guidelines for developing
and Implementing a llhead protection program are found im 0 Guidetines
for Applicants for State Welihead Protection Program Assistance Funds
under th. Safe Drinking Water Act° (U.S. EPA, 1987a).
A system using a ground water source under the influence of surface
water that does not have filtration in place must begin monitoring and
reporting in accordance with 5141.74(b) and 5141.75(a), respectively, to
determine whether It meets the criteria for avoiding filtration beginning
December 30, 1990 or six months after the Primacy Agency determines that
7—4

-------
the ground water source is under the influence of surface water, whichever
is later. Within 18 months following the determination that a system is
under the influence of surface water, the Primacy Agency must determine,
using the same criteria that apply to systems using a surface water
source, whether the system must provide filtration treatment. As for
systems using a surface water source, the Primacy Agency must evaluate the
data on a case-by-case basis to determine conditions which will trigger
the need for filtration.
Beginning December 30,1991 or 18 months after the determination that
a system is under the direct influence of surface water, whichever is
later, the criteria for avoiding filtration In 5141.71(a) and (b) and the
requirements for unfiltered systems in S141.71(c) and S141.72(a) go into
effect, unless the Primacy Agency has determined that filtration is
required. As with systems using a surface water source, subsequent
failure to comply with any one of the criteria for avoiding filtration
requires the installation cf filtration treatment. Thus, beginning
December 30, 1991 or 18 months after the Primacy Agency determines that
a system is using a ground water source under the direct influence of
surface water, whichever is later, a system which fails to meet any one
of the ,criteria to avoid filtration must install filtration and comply
with the requirements for filtered systems within 18 months of the failure
or by June 29, 1993, whichever Is later. As for unfiltered systems,
systems under the direct influence of surface water may apply for an
exemption to extend the time period for Installing filtration.
Any system using a ground water source that the Primacy Agency
determines is under the direct influence of surface water and that already
has filtration in place at the time of the Primacy Agency determination
must meet the treatment technique, monitoring and reporting requirements
for filtered systems begInning June 29, 1993 or 18 months after the
Primacy Agency determination, whichever Is later.
7-5

-------
7.5 Responses for Systems not Meeting SWTR Criteria
7.5.1 Introduction
Systems which presently fail to meet the SWTR criteria may be able
to upgrade the system’s design and/or operation and maintenance in order
to achieve co pliance. The purpose of this section is to present options
which may be followed to achieve comphance.
7.5.2 Systems Not Filtering
Systems not filtering must meet the criteria to avoid filtration
beginning December 30, 1991 and on a continuing basis thereafter or
install filtration. Systems not filtering can be divided into two
categories:
A. Those systems not currently meeting the SWTR criteria but with
the ability to upgrade to meet them.
B. Those systems not able to meet the SWTR criteria by December
30, 1991. If the installation of filtration is notpossible
by June 29, 1993 the system may request an exemption and take
interim measures to provide safe water to avoid violation of
a treatment technique requirement.
Systems in Category A
Examole A - Response Situation
Condition : System is not meeting the source water fecal and/or
total coliform concentrations but has not received judgment on the
adequacy of Its watershed control.
Response Options :
— Monitor for fecal coliforms rather than total coliforms if
this Is not already done. Fecal coliforms are a direct
Indicator of fecal contamination where total coliforms are
not. If total colifori levels are exceeded but fecal levels
are not the system meets the criteria.
- Take appropriate action in the watershed to assure fecal and
total coliform concentrations are below the criteria, such as
elimination of animal activity near the source water intake.
7-6

-------
Examole B — ResDonse Situation
Condition : System meets the source water quality criteria,
watershed control requirements, and is maintaining a disinfectant
residual within the distribution system, but is not able to meet the
CT requirements due to lack of contact time prior to the first
customer.
Resoonse Ootions :
— Increase the application of disinfectant while monitoring THM
levels to ensure they remain below the MCL.
— Add additional contact time through storage to obtain an
adequate CT.
— Apply a more effective disinfectant such as ozone.
Systems in Category B
Examole A — ResDonse Situation
Condition : System meets the source water turbidity but not the
fecal coliforin requirements. A sewage treatment plant discharges
into the source water. A determination has been made that the
system does not have adequate watershed control.
ResDonse Ootions :
- Purchase water from a nearby surveyor or use an alternate
source such as ground water if available.
— Take steps to install filtration, applying for an exemption
(time delay) as presented In Section 9 where appropriate.
Examole B
Condition : The source water exceeds a turbidity of 5 NTU for more
than two periods In a year under normal weather and operating
conditions.
Response Options :
— Purchase water from a nearby purveyor or use an alternate
source such as ground water if available.
— Take steps to Install filtration, applying for an exemption
(time de’ay) as presented In SectIon 9 where appropriate.
7—7

-------
In the interim prior to adoption of either of the above options,
certain protective measures may be appropriate. One protective
measure which can be used would be the issuance of a public notice
to boil all water for consumption during periods when the turbidity
exceeds 5 NTU. If such a notice is issued, the utility should
continue sampling the distribution system for chlorine residual and
total coliforms, and initiate measurement of HPCs in the distribu-
tion system. These data and the raw water turbidity should be used
to determine when to ii ft the boil water notice.
The notice could be lifted when:
— The historical (prior to high turbidity) disinfectant residual
concentration is reestablished in the distribution system;
- The total coliform requirements are met;
- The HPC count is less than 500/al; and
- The turbidity of the raw water is less than 5 NTU.
7.4.3 Systems Currently Filtering
Systems which are currently filtering must meet the SWTR criteria
within 48 months of the SWIR to be in compliance, after which the criteria
must be continually met for the system to be In compliance.
Examole A - Resoonse Situation
Condition : A direct filtration plant Is treating a surface water
which is not co atlble with this treatment process. The system is
not achieving its required turbidity performance or disinfection
criteria.
Response Ootions :
- Optimize coagulant dose.
- Reduce filter loading rates.
• Evaluate the effect on performance of Installing flocculation
and sedimentation ahead of the filters.
7-8

-------
£xamDle B - ResDonse Situation
Condition : A filtration plant is using surface water which is
compatible with its treatment system. The system is not achieving
disinfection performance criteria required by the Primacy Agency to
achieve a 1-log inactivation of Giardia cysts; however, it is
meeting the requirements of the Total Coliform Rule.
Resoonse Ootions :
- Increase disinfectant dosage(s).
- Install storage facilities to increase disinfectant contact
time.
- Ensure optimum filtration efficiency by:
- Use of a filter aid.
— Reduction in filter loading rates.
- More frequent backwashing of filters.
The Primacy Agency may grant additional removal credit for optimum
filtration.
EPA intends to promulgate Hational Primary Drinking Water Regula-
tions to regulate levels of disinfectants and disinfectant by—product when
it promulgates disinfection requirements for ground water systems
(anticipated in 1992). EPA is concerned that changes required in
utilities’ disinfection practices to meet the required inactivations for
the SWTR might be inconsistent with treatment changes needed to comply
with the forthcoming regulations for disinfectants and disinfection
by-products. For this reason, the E A is allowing Primacy Agencies
discretion in determining the level of disinfection required for filtered
systems to meet the overall treatment performance requirements specified
In the rule or recoemended based on source water quality.
During the interim period, prior to promulgation of the disinfection
by-product regulation, EPA recoemends that the Primacy Agency allow more
credit for Giardia cyst and virus removal than generally recoemended.
This nter1m level Is recoemended in cases where the Primacy Agency
determines that a system is not currently at a significant risk from
microbiological concerns at the existing level of disinfection and that
7-9

-------
a deferral is necessary for the system to upgrade its disinfection process
to optimafly achieve comphance with the SWIR as well as the forthcoming
disinfection by-product regulations. Section 5.5.3 presents some
guidelines for establishing interim disinfection requirements.
7 - 10

-------
8. PUBLIC P4OTIFICATIOJI
The SWTR specifies that the public notification requirements of the
Safe Drinking Water Act (SOWA) and the implementing reguTations of 40 CFR
Paragraph 141.32 must be followed. These regulations divide public
notification requirements into two tiers. These tiers are defined as
follows:
1. Tier 1:
a. Failure to comply with MCL
b. Failure to comply with prescribed treatment technique
c. Failure to comply with a variance or exemption schedule
2. Tier 2:
a. Failure to comply with monitoring requirements
b. Failure to comply with a testing procedure prescribed
by a NPDWR
c. Operating under a variance/exemption. This is not
considered a violation but public notification is
required.
The SWIR classifies violations of Sections 141.70, 141.71(c),
141.72 and 141.73 (i.e., treatment technique requirements as specified in
Section 141.76) as Tier 1 violations and violations of Section 141.74 as
Tier 2 violations. Violations of 141.75 (reporting requirements) do not
require public notification.
There are certain general requirements which all public notices must
meet. All notices must provide a clear and readily understandable
explanation of the violation, any potential adverse health effects, the
population at risk, the steps the s/stem is taking to correct the
violation, the necessity of seeking alternate water supplies (if any) and
any preventative measures the consumer should take. The notice must be
conspicuous, not contain any unduly technical language, unduly small print
or similar problems. The notice must include the telephone number of the
owner or operator or designee of the public water system as a source of
additional information concerning the violation where appropriate. The
notice must be bi- or multilingual if appropriate.
In addition, the public notification rule requires that when
providing information on potential advent health effects In Tier 1 public
8-1

-------
notices and in notices on the granting and continued existence of a
variance or exemption, the owner or operator of a public water system must
include certain mandatory health effects language. For violations of
treatment technique requirements for filtration and disinfection, the
mandatory health effects language is:
Microbioiogical Contaminants
The United States Environmental Protection Agency (EPA) sets drinking
water standards and has determined that microbiological contaminants are
a health concern at certain levels of exposure. If water is inadequately
treated, microbiological contaminants in that water may cause disease.
Disease symptoms may Include diarrhea, cramps, nausea, and possibly
jaundice and any associated headaches, and fatigue. These symptoms,
however, are not just associated with disease-causing organisms in
drinking water 1 but also may be caused by a number of factors other than
your drinking water. EPA has set enforceable requirements for treating
drinking water to reduce the risk of these adverse health effects.
Treatment such as filtering and disinfecting the water removes or destroys
microbiological contaminants. Drinking water which Is treated to meet EPA
requirements is associated with little to none of this risk and should be
considered safe.
Further, the owner or operator of a conrunity water system must give
a copy of the most recent notice for any Tier 1 violations to all new
billing units or hookups prior to or at the time service begins.
The medium for performing public notification and the time period
in which notification aust be sent varies with the type of violation and
Is specified in Section 141.32. For Tier 1 violatIons (I.e., violations
of Sections 141.70, 141.71 141.72 and 141.73), the owner or operator of
a public water system must give notice:
1. By publication In a local daily newspaper as soon as possible
but in no case later than 14 days after the violation or
failure. If the area does not have a daily newspaper 1 then
notice shall be given by publication In a weekly newspaper of
general circulation in the area, and
2. By either direct mall delivery or hand delivery of the notice,
either by itself or with the water bill not later than 45 days
after the violation or failure. The Primacy Agency say waive
this requirement If it determines that the owner or operator
has corrected the violation within the 45 days.
8-2

-------
Although the SWIR does not specify any acute violations, the Primacy
Agency may specify some Tier 1 violations as posing an acute risk to human
health; for example these violations may include:
1. A waterborne disease outbreak in an unfiltered supply.
2. Turbidity of the water prior to disinfection of an unfiltered
supply or the turbidity of filtered water exceeds 5 NTU at any
time.
3. Failure to maintain a disinfectant residual of at least 0.2
mg/i In the water being delivered to the distribution system.
For these violations or any others defined by the Primacy Agency as
“acute” violations, the system must furnish a copy of the notice to the
radio and television stations serving the area as soon as possible but in
no case later than 72 hours after the violation. Depending upon circuin-
stances particular to the system, as determined by the Primacy Agency, the
notice may instruct that all water should be boiled prior to consumption.
Following the initial notice, the owner or operator must give notice
at least once every three months by mail delivery (either by Itself or
with the water bill), or by hand delivery, for as long as the violation
or failure exists.
There are two variations on these requirements. First, the owner
or operator of a coimnunity water system in an area not served by a daily
or weekly newspaper must give notice within 14 days after the violation
by hand delivery or continuous posting of a notice of the violation. The
notice must be In a conspicuous place In the area served by the system and
must continue for as long as the violation exists. Notice by hand
delivery must be repeated at least every three months for the duration of
the violation.
Secondly the owner or operator of a nonconinunity water system
(i.e., one serving a transitory population) may give notice by hand
delivery or continuous posting of the notice In conspicuous places In the
area served by the system. Notice must be given within 14 days after the
violation. If notice Is given by posting, then it must continue as long
8-3

-------
as the violation exists. Notice given by hand delivery must be repeated
at least every three months for as long as the violation exists.
For Tier 2 violations (i.e., violations of 40 CFR 141.74, analytical
and monitoring requirements) notice must be given within three months
after the violation by publication in a daily newspaper of general
circulation, or if there is no daily newspaper, then in a weekly
newspaper. In addition, the owner or operator shall give notice by mail
(either by itself or with the water bill) or by hand delivery at least
once every three months for as long as the violation exists. Notice of
a variance or exemption must be given every three months from the date it
is granted for as long as it remains in effect.
If the area is not served by a daily or weekly newspaper, the owner
or operator of a coanunity water system must give notice by continuous
posting in conspicuous places In the area served by the system. This must
continue as long as the violation does or the variance or exemption
remains In effect. Notice by hand delivery lust be repeated at least
every three months for the duration of the violation or the variance of
exemption.
For nonconinunity water systems, the owner or operator may give
notice by hand delivery or continuous posting in conspicuous places;
beginning within 3 months of the violation or the variance or exemption.
Posting must continue for the duration of the violation or variance or
exemption and notice by hand delivery must be repeated at least every
3 months during this period.
The Primacy Agency may allow for vner or operator to provide less
frequent notice for minor monitoring violations (as defined, by the
Primacy Agency jf EPA has approved the Primacy Agency’s substitute
requirements contained in a program revision application).
To provide further assistance in preparing public notices, several
examples have been provided. However, each situation is different and
may call for differences in the content and tone of the notice. All
notices must comply with the general requirements specified above.
8-4

-------
Example 1 — Tier 1 Violation-Unfiltered SUDD1V
Following is an example of a Tier 1 violation which may be
considered by the Primacy Agency to pose an acute risk to human health.
A system which does not apply filtration experiences a breakdown in
the chlorine feed systems and the switchover system fails to activate the
backup systems. A number of hours pass before the operator discovers the
malfunction. The operator, upon discovery of the malfunction, contacts
the local television and radio stations and announces that the public is
receiving untreated water. The announcement may read as follows:
We have just received word from the Aswan Water Board that a
malfunction of the disinfection system has allowed untreated water
to pass into the distribution system. Thus, this system providing
drinking water is in violation of a treatment technique requirement.
The United States Environmental Protection Agency (EPA) sets
drinking water standards and has determined that microbiological
contaminants are a health concern at certain levels of exposure.
If water is inadequately treated, microbiological contaminants in
that water may cause disease. Disease symptoms may include
diarrhea, cramps, nausea, and possibly jaundice and any associated
headaches, and fatigue. These symptoms, however, are not just
associated with disease-causing organisms in drinking water, but
also may be caused by a number of factors other than your drinking
water. EPA has set enforceable requirements for treating drinking
water to reduce the risk of these adverse health effects. Treatment
such as filtering and disinfecting the water removes or destroys
microbiological contaminants. Drinking water which is treated to
meet EPA requirements is associated with little to none of this risk
and should be considered safe.
The temporary breakdown in disinfection may have allowed micro-
organisms to pass into the distribution system. The operation of
the system has been restored so that no further contamination of
the distribution system will occLlr. Any further changes will be
announced.
Additional information is available at the following number:
235-WATER.
A direct mailing of the notice Is provided within 45 days of the
occurrence.
Examole 2 - Tier 1 Violation-Unfiltered SUDD1Y
Following is an example of a Tier 1 vIolation which may be
considered by the Primacy Agency to pose an acute risk to human health.
8-5

-------
A system supplies an unfiltered surface water to its customers.
During a period of unusually heavy rains caused by a hurricane in the
area 1 the turbidity of the water exceeds 5 IITU. The turbidity data during
which the heavy rains occur is as follows:
Day 1 NTIJ Day 2 tITU Day 3 NTIJ Day 4 MTU Day 5 NTU
0.4 0.8 0.7 0.7 7.6
0.4 0.5 0.4 7.6 3.1
0.5 0.5 0.4 11.3 2.7
0.7 0.4 0.5 9.6 0.7
1.1 0.4 0.4 7.2 0.8
0.9 0.6 0.6 5.0 0.5
The following public notice was prepared and, submitted to the local
newspaper, television and radio stations within 72 hours of the first
turbidity exceedence of 5 NTU.
The occurrence of heavy rains In our watershed Is causing a rise in
the turbidity of the drinking water supplied by Fairfax Water
Company.
Turbidity is a measurement of particulate matter In water. It Is
of significance In drinking water because irregularly shaped
particles can both harbor microorganisms and interfere directly with
disinfection which destroys microorganisms. While the particles
causing the turbidity may not be harmful or even visible at the
concentrations measured 4 the net effect of a turbid water Is to
Increase the survival rate of microorganisms contained In the water.
This is of concern because several diseases are associated with
waterborne microorganisms.
Because of the high turbidity levels, the Fairfax system Is in
violation of a treatment requir nent set by the Environmental
Protection Agency (EPA).
The United States Environmental Protection Agency (EPA) sets
drinking water standards and has determined that microbiological
contaminants are a health concern at certain levels of exposure.
If water Is Inadequately treated, microbiological contaminants in
that water may cause disease. Disease sy toms may include
diarrhea, cra s, nausea, and possibly jaundice and any associated
headaches, and fatigue. These sy t s, however, are not just
associated with disease—causing organisms In drinking water, but
also may be caused by a number of factors other than your drinking
water. EPA has set enforceable requirements for treating drinking
water to reduce the risk of these adverse health effects. Treatment
such as filtering and disinfecting the water removes or destroys
microbiological contaminants. Drinking water which Is treated to
8-6

-------
meet EPA requirements is associated with little to none of this risk
and should be considered safe.
In order to protect yourself from illness, all water from the
Fairfax system used for drinking, cooking and washing dishes should
be boiled at a rolling boil for one minute.
The system is being closely monitored and a notice will be issued
when the water returns to an acceptable quality and no longer needs
to be boiled.
The utility continues sampling the distribution system frr chlorine
residual and total coliforms, and initiates measurement of the KPCs in the
distribution system. The notice is lifted when all the following are met:
— The historical (prior to high turbidity) disinfectant residual
concentration is reestablished in the distribution system.
• The total coliforin requirements are met.
- The HPC count is cSOO/ml.
- The turbidity of the raw water is less than 5 NTU.
The Primacy Agency most decide whether the turbidity event was unusual or
unpredictable and whether filtration should be installed.
Example 3 - Tier 1 Violation • Filtered Supply
A conventional treatment plant is treating a surface water. A
malfunctioning alum feed system resulted In an increase of the filter
effluent turbidities. The effluent turbidity was between 0.5 and 1.0 NTU
in 20 percent of the samples for the mo th. The utility Issued a notice
which was published in a local daily newspaper wIthin 14 days after the
violation. The notice read as follows:
During the previous month, the Baltic Water Treatment Plant
experienced difficulties with the chemical feed system. The
malfunctions caused an effluent turbidity level above 0.5 NTU in 20
percent of the samples for the month. The current treatment
standards require that the turbidity must be less than 0.5 NTU in
95 percent of the monthl ’ samples. The Baltic drinking water system
has thus been In violation of a treatment technique requirement.
The United States Environmental Protection Agency (E!A) sets
drinking water standards and has determined that microb oiog cal
8-7

-------
contaminants are a health concern at certain levels of exposure.
If water is inadequately treated, microbiological contaminants in
that water may cause disease. Disease symptoms may include
diarrhea, cramps, nausea, and possibly jaundice and any associated
headaches, and fatigue. These symptoms, however, are not just
associated with disease-causing organismS in drinking water, but
also nay be caused by a number of factors other than your drinking
water. EPA has set enforceable requirements for treating drinking
water to reduce the risk of these adverse health effects. Treatment
such as filtering and disinfecting the water removes or destroys
microbiological contaminants. Drinking water which is treated to
meet EPA requirements is associated with little to none of this risk
and should be considered safe.
The chemical, feed and switcho er components of the system have been
repaired and are in working order and turbidity levels are meeting
the standard. It is unlikely that illness will result from the
turbidity exceedences previously mentioned because Continuous
stringent disinfection conditions were in effect and the system was
in compliance with other microbiological drinking water standards
pertaining to microbiological contamination. However, a doctor
should be contacted in the event of Illness. For additional
information call, 1—800-726-WATER.
8-8

-------
9. EXEMPTIONS
9.1 Overview of Requirements
Section 1416 of the Safe Drinking Water Act allows a Primacy Agency
to exempt any public water system within Its jurisdiction from any
treatment technique requirement imposed by a national primary drinking
water regulation upon a finding that:
1. Due to compelling factors (which may include economic
factors), the public water system is unable to comply with the
treatment technique requirement;
2. The public water system was in operation on the effective date
of the treatment technique requirement or, for a system that
was not in operation by that date, only if no reasonable
alternative source of drinking water is available to the new
system; and
3. The granting of the exemption will not result In an unreason-
able risk to health.
If a Primacy Agency grants a public water system an exemption, the
Agency must prescribe, at the time the exemption is granted, a schedule
for:
1. Compliance (including increments of progress) by the public
water system with each treatment technique requirement with
respect to which the exemption was granted; and
2. ImplementatIon by the system of such c ntrol measures as the
Primacy Agency may require during the period the exemption is
in effect.
Before prescribing a schedule, the Primacy Agency must provide
notice and opportunity for a public hearing on the schedule. The schedule
prescribed must require compliance by the public water system with the
treatment technique requirement as expeditiously as practicable, but in
no case later than one year after the exemption Is issued (except that,
if the system meets certain requirements, the final date for compliance
may be extended for a period not to exceed three years from the date the
exemption is granted). For systems serving less than 500 service
9—1

-------
connections, and meeting certain additional requirements, the Primacy
Agency may renew the exemption for one or more additional two-year
periods.
Under the SWIRI no exemptions are allowed from the requirement to
provide disinfection for surface water systems, but exemptions are
available to reduce the degree of disinfection required. Exemptions from
the filtration requirements are available. The following sections present
guidelines for evaluating conditions under which exemptions are appropri-
ate.
9.2 Reconrended Criteria
In order to obtain an exemption from the SWTR, a system must meet
certain minimum criteria to assure no unreasonable risk to health. These
should be applied before looking at other factors such as economics.
Reconrended minimum criteria for assuring no unreasonable risk to health
exists are listed below.
Systems which do not Drovide filtratton
— Practice disinfection to achieve at least a 2-log inactivation
of Giardia cysts; or comply with the disinfection requirements
for the distribution system as defined in Section 141.72(b)
of the SWTR.
- Comply with the monthly coliform HCL; or provide bottled water
(or another alternate water source) or point of use treatment
devices for their customers in which representive samples
comply with all the MCL National Primary Drinking Water
Regulations.
EPA recoemends that In order to obtain an extension to the initial
1 year exemption period in addition to the required elements in Section
1416, the system would need to be in compliance with the monthly coliform
NCL, satisfy the above disinfection criteria and not have any evidence of
waterborne disease outbreaks attributable to the system at the end of that
first exemption period. If at any point during the extended exemption
period the system did not meet these conditions, the ex t1On should be
withdrawn and the system should be subject to an enforcement action.
9-2

-------
Systems which Drovlde filtration
— Practice disinfection to achieve at least a 0.5 109 inactiva-
tion of Giardia cysts; or comply with the thsinfection
requirements for the distribution system as defined in
Section 141.72 of the rule.
- Comply with the monthly coliform MCL; or provide bottled water
(or another alternate water source) or point of use treatment
devices for their customers in which representive samples
comply with all the MCL National Primary Drinking Water
Regulations.
— Take all practical steps to Improve the performance of its
filtration system.
In order to obtain an extension to the initial exemption period, in
addition to the required elements in Section 1416, the system should be
in compliance with the collfonn L, satisfy the above disinfection
criteria and not have any evidence of waterborne disease outbreaks
attributable to the treatment system at the end of that first exemption
period. If at any point during the extended exemption period the system
did not meet these conditions, the exemption should be withdrawn and the
system should be subject to an enforcement action. In addition, the
system must continue to be taking steps to improve the performance of its
filtration system to achieve the criteria specified in the SWTR.
Once these minimum requirements are applied, the Primacy Agency
should look at the other factors as described in Sections 9.3. 9.4, and
9.5.
9.3 Comoe11in Factors
Compelling factors are often associated with small systems. The
major compelling factor tends to be economic. In some cases the
compelling factor may not be solely economic, but rather the contractual
and physical infeasibility of having a required treatment installed within
the time period specified In the regulation. For example, it may not be
feasible for a very large system to install filtration by June 1993 If
required. In such cases exemptions are also appropriate. Additional
considerations for small systems are presented in Appendix 1.
9-3

-------
If system improvements necessary to comply with the SWTR incur costs
which the Primacy Aaency determines pose an economic barrier to acquisi-
tion of necessary treatment, the system fulfills the criteria of
demonstrating a compelling hardship which makes it unable to meet the
treatment requirements. In such cases, the EPA believes it is reasonable
to grant an exemption if the system also meets the criteria in 9.4 and
9.5.
The USEPA document, Technologies and Costs for the Removal of
Microbial Contaminants from Potable Water Supplies, contains costs
associated with available treatment alternatives (USEPA, 1988b). Costs
found in this document, or those generated from more site—specific
conditions, can be used as the basis for determining the ability of a
system to afford treatment. The total annual water production costs per
household for a system can be estimated based on the household water usage
and the production costs per thousand gallons. As estimated In the above
cited USEPA document, each cent per thousand gallons of treated water is
approximately equivalent to $1 per year per household If a household water
usage of 100,000 gallons per year is assumed.’ This estimate will need to
be adjusted according to water usage for cases where the household usage
differs from 100,000 gallons per year.
The following examples are presented to provide guidance in
estimating costs for a system to upgrade its system or install filtration.
This cost Information could be used for determining whether a system might
be eligible for an exemption.
Examole 1
A water system which supplies an average daily flow of 0.05 .gd to
a small urban counlty receives its water supply from a lake. The system
currently provides disinfection with chlorine but does not provide
filtration. The system reviewed Its source water quality and found the
characteristics to be as follows:
This is the national average residential household consumption reported
in: Final Descriptive SulDary — 1986 Survey of Coemunity Water Systems.
October 23, 1987. USEPA: Office of Drinking Water.
9-4

-------
Total coliforins 1,000/100 ml
Turbidity 10 - 13 NTU
Color 6-9CU
Based upon the criteria in the SWTR . this source requires filtration
and a review of the water quality criteria presented in Table 4-2
indicates that the treatment technique best suited to these source
conditions is conventional treatment. A conventional package treatment
plant with a capacity of 0.068 MGD may be purchased and put on line at
a cost of $277/household-year not including real estate, piping or raw
water pumping costs which may be significant depending on the plant
location. 2 EPA has estimated that, on average, these costs might add
another 50% depending on site specific factors (USEPA, 1989)
Thus the cost estimate for implementing filtration indicates that
the increase In the average annual household water bill would be
approximately $277 plus the cost of real estate, piping, and raw water
pumping as needed. The Incomes of people In the coalnunity and the current
water bills can be reviewed by the Primacy Agency along with these
estimated costs to determine if an undue economic hardship is Incurred by
these treatment methods. Upon determination that an economic hardship is
incurred, the Primacy Agency may grant an exemption from filtration,
provided that the system can assure the protection of the health of the
coninunity. However, if the water supply system for a nearby comounity
meets the drinking water standards there is the ability to hook up to
that system, an exemption generally should not be granted unless such
costs also presented an economic hardship.
ExamDle 2
A large urban co unity, with a median annual Income of $25,000 per
family, Is supplied with water from lakes and reservoirs. The coam unity
places an average daily demand of 3 mgd on the supply system. The
watershed of the system Is moderately populated and used for farming and
2 Table VI-3 (Technoloqles and Costs for the Removal of Microbial
Contaminants ros Potable Water Suppfles, USEPA, 1988b) lists the total
costs as 277.4 cents/lOGO gal. Estimated costs for real estate, piping
and raw water pumping as a function of site specific conditions are
available In Table E-1, E-2, and E-3 of this same document.
9-5

-------
grazing. The system currently provides filtration using diatomaceous
earth filtration and disinfection with chloramines.
A review of the source and finished water quality was conducted to
evaluate the plant’s perforiiiance. The source water quality was determined
to be:
Total coliforms 30 - 40/100 ml
Turbidity 2 - 3 NTU
Color 1-2CU
Diatomaceous earth is thcrefore an acceptable filtration method 3
However, review of the finished water showed that a residual in the
distribution system is only maintained 80 percent of the time. In
addition to this, coliforms were detected In 10 percent of the samples
taken over the twelve month period. Inspection of the chlorination
equipment showed the equipment is deteriorated. Review of the monthly
reports showed that the coliforms appeared in the distribution system
shortly after the chiorinators malfunctioned. This observation led to the
conclusion that new disinfection facilities were needed.
The source water quality and available contact time after disinfec-
t on were then used to determine the most appropriate disinfectant for the
system. As described in Section 5.5, ozone, chlorine or chlorine dioxide
can be used as primary disinfectants given these conditions. A prelimi-
nary review of costs for applying the various disinfectants showed
chlorine to be the most economical at a cost of $2.8/household/year 1
(USEPA, 1988b). This cost does not include backup equipment; however,
even with providing duplicate equipment oubling this cost to $5.6/house—
hold/ year 1 the I.prove.ent Incurs minimal cost and the Primacy Agency
should not grant the syste. an exemption based on economic hardship.
As determined from Table 4-2 of Section 4.
Table VI-12 (USEPA. 1988b) Fists a total cost of 2.8 cents/l000 gal for
a plant capacity of 5.85 mgd.
f .8 cents) {S1/household—vear ) $2.8/household-year
(1,000 gal) (cents/1000 gal)
9-6

-------
9.4 Evaluation of Alternate Water Suo lv Sources
Systems which would incur very high costs for installing a required
treatment to comply with the SWTR, should evaluate the possibility of
using an alternate source. These alternate sources include:
- The use of ground water
- Connection to a nearby water purveyor
- Use of an alternate surface water supply
When considering the use of ground water, the purveyor must
determine the capacity of the underlying aquifer for supplying the demand.
The water quality characteristics of the aquifer must be evaluated to
determine what treatment may be needed to meet existing standards. The
cost of the well construction and treatment facilities must then be
determined and converted Into a yearly cost per household.
The connection to a nearby purveyor involves contacting the purveyor
to determine their capacity and willingness to supply the water. Once it
has been determined that the alternate source meets all applicable
drinking water standards, the cost of the transmission lines, distribution
system, and other facilities (e.g. disinfection, repumping, etc.) must
then be determined and amortized into a yearly cost per household.
If the cost for using an alternate source is found by the Primacy
Agency to present an economic hardship, and the purveyor can demonstrate
that there will be no unreasonable risk to health, the Primacy Agency may
grant an exemption to the SWTR for the purveyor and develop a schedule of
compliance.
9.5 ProtectIon of Public Health
Systems which apply for an exemption from the SWTR must demonstrate
to the Primacy Agency that the health of the coemunity will not be put at
risk by the granting of such an exemption. A system should be able to
provide adequate protection for the public health by meeting the minimum
suggested EPA requirements in Section 9.2. However, a Primacy Agency may
specify additional measures or criteria a system must meet to protect
public health, depending on the particular circumstances. Systems with
currently unfiltered surface water supplies which fail to meet the source
9-7

-------
water quality criteria will be required to install filtration as part of
their treatment process. However, it mey take 3 to 5 years or more before
the filtration system can be designed, constructed and begin operation,
thereby justifying the granting of an exemption. During this period,
possible interim measures which the system could take to further satisfy
the Primacy Agency’s concern include one or more of the following:
a. Use of higher disinfectant dosages without exceeding the TTHM
NCL (even for systems not currently subject to this MCI)
b. Installation of a replacement or additional disinfection
system which provides greater disinfection efficiency and
which can be integrated into the new filtration plant
c. Increasing the monitoring and reporting to the Primacy Agency
d. Increasing protection of the watershed
e. Increasing the frequency of sanitary surveys
f. Temporarily purchasing water from a nearby water system
g. For small systems, temporary installation of a mobile
filtration (package) plant
h. Increasing contact time by rerouting water through reservoirs
In some cases systems may be able to increase their disinfection
dosages during the interim period to provide additional protection against
pathogenic organisms. This alternative should be coupled with a
requirement for increased monitoring for coliforms, HPC and disinfectant
residual within the distribution system. However, disinfectant dosage
should not be increased If this would result in a violation of the TTI4M
MCLI even for systems not currently subject to this NCL.
Systems which are planning to Install filtration may be able to
utilize a more efficient disinfectant that can later be Integrated into
the filter plant. Currently ozone and chlorine dioxide are considered to
be the most efficient disinfectants.
For all systems which do not meet the source water quality criteria
must install filtration, EPA recoanends that during the interim period
the Primacy Agency Increase Its surveillance of the system and require
9-8

-------
increased monitoring and reporting requirements to assure adequate
protection of the public health.
Any required increases in watershed control and/or on-site
inspections will not alleviate the need for more stringent disinfection
requirements and increased monitoring of the effectiveness of the system
employed. The.ir purpose would be to identify and control all sources of
contamination so that the existing system will provide water of the best
possible quality.
For some systems, It may be possible to purchase water from a nearby
system on a temporary basis. This may involve no more _han the use of
existing interconnections or it may require the installation of temporary
connections. -
Trailer mounted filtration units (package plants) are sometimes
available from state agencies for emergencies or may be rented or leased
from equipment manufacturers.
Systems may also be required to supply bottled water or install
point-of-entry (POE) treatment devices. For the reasons listed below,
these alternatives should only be utilized if the previously mentioned
alternatives are not feasible:
— In many states bottled water is subject only to the water
quality requirements of the FDA as a beverage and not to the
requirements of the Safe Drinking Water Act.
- Point—of—entry treatment devices are not currently covered by
performance or certification requirements which would assure
their effectiveness or performance.
If the Installation of POE devices Is required, the selection of the
appropriate treatment device should be based upon a laboratory or field
scale evaluation of the devices. A guide for testing the effectiveness
of POE units in the microbiological purification of contaminated water is
provided in Appendix N.
Several Issues arise with the use of POE devices. These Include
establishing who or what agency (1) has the responsibility for ensuring
compliance with standards; (2) retains ownership of the treatent units;
(3) performs monitoring, analyses and maintenance; and (4) manages the
9-9

-------
treatment program and maintains Insurance coverage for damage and liabil-
ity. It should also be considered that there is no significant increase
in risk over centrally treated water.
These issues should be borne in mind when POE as a treatment
alternative is being considered.
Systems with currently unfiltered surface water supplies which meet
the source water quality criteria, but do not meet one or more of the
other requirements for watershed control, sanitary survey, compliance with
annual coliform MCL or disinfection by-product regulation(s), will be
required to Install filtration unless the deficiencies can be corrected
within 48 months of promulgation of the SWTR. Interim protection measures
include those previously listed.
Systems with currently unfiltered surface water supplies which meet
the source water quality criteria and the site specific criteria but which
do not meet the disinfection requirements, will be required to install
filtration unless the disinfection requirements (adequate CT and/or
disinfection system redundancy) can be met. During the interim period,
available options include:
a. Temporary installation of a mobile treatment plant
b. Temporary purchase of water from a nearby purveyor
c. Increased monitoring of the system
d. Installation of temporary storage facilities to increase the
disinfectant contact time
Currently filtered supplies which fall to meet the turbidity or
disinfection performance criteria presented in SectIon 5 wIll be required
to evaluate and upgrade their treatment facilities in order to attain
compliance. During the Interim period available options for Improving the
finished water quality include:
a. Use of a filter aid to Improve filter effluent turbidltles
b. Increased disinfectant dosages
c. The addition of an alternate disinfectant is an option after
the disinfection by-products rule Is promulgated
9 - 10

-------
d. Reduction in filter loading rates with subsequent reduction
in plant capacity
e. Installation of temporary storage facilities to increase
disinfectant contact time
9.6 Notification to EPA
The SDWA requires that each Primacy Agency which grants an exemption
notify EPA of the granting of this exemption. The notification must
contain the reasons for the exemption, including the basis for the finding
that the exemption will not result in an unreasonable risk to public
health and document the need for the exemption.
9 - 11

-------
REFERENCES

-------
REFERENCES
A1i-Ani, N.; McElroy, J. H.; Hibler, C. P.; Hendricks 1 D. W. Filtration
of Giardia Cysts and other Substances, Volume 3: Rapid Rate Nitration .
EPA-600I2-85-027, U.S. Environmental Protection Agency, WERL, Cincinnati,
Ohio, April, 1985.
American Public Health Association; American Water Works Association;
Water Pollution Control Federation. St&ndard Methods for the Examination
of Water and W sttw&ter , 16th ed., pp. 134-6, 298-310, 827—1038, 1985.
American Public Health Association; American Water Works Association;
Water Pollution Control Federation. Standard Methods for the Exam nation
of Water and Wastewater , 17th ed., 1989.
American Water Works Association. Manual of Water Supply Practices arid
Water Chlorination Principles and Practices, 1973.
American Water Works Association Research Foundation (AWWARF). A Sunnary
of State Drinking Water Regulations and Plan Review Guidance. June, 1986.
Bader, H.; Hoigne, J. Determination of Ozone in Water by the Indigo
Method, Water Research 15; 449-454, 1981.
Bellamy 4 W. 0.; Lange, K. P.; Hendricks, 0. W. Filtration of Giardia Cysts
and Other Substances. Volume 1: Diatomiceous Earth Filtration .
EPA-600/2-84-114, U.S. Environmental Protection Agency, Cincinnati, Ohio,
1984.
Bellamy, W. C.; Silverman, G. P.; HendrIcks, 0. W. Filtration of Giardli
Cysts and Other Substances. Volume 2: Slow Sand Filtration . EPA-600/2-
-85-026, U.S. Environmental Protection Agency, MERL, Cincinnati, Ohio,
April, 1985.
Bishop, S.; Craft, 1. F.; Fisher, 0. R.; Ghosh, N.; Prendiville, P.W.;
Roberts, K. J.; Steimle, S.; Thompson, J. The Status of Direct Filtration,
Coimiiittee Report . J.AWWA, 12(7):405.411, 1980.
Bouwer, H. Ground Water Hydrology . McGraw Hill Book Co., New York,
pp. 339-356, 1978.
Brown, 1. S .; Mai ms, J. F., Jr.; Moore, B. 0. Virus Retnoval by Diatoms-
ceous Earth Filtration — Part 1 & 2. J.AWWA 66(2):98-102, (12):735-738,
1974.
Bucklin, K.; Sairtharajah, A.; Cranston, K. Characteristics of Initial
Effluent Quality and Its Implications for the Filter-to-Waste Procedure.
AOA Research Foundation Report. Novether, 1988.
—1—

-------
Carison, D.A.; Seabloom, R.W.; DeWalle, F.D.; Wetzler, T.F.; Evqeset, J.;
Butler, R.; Wangsuthachart, S.; Wang, S. Ultraviolet Disinlection of
Water for Small Water Systems. EPA/600/2.85.092 , U.S. Environmental
Protection Agency, Water Engineering Reserach Laboratory, Drinking Water
Research Division, Cincinnati, Ohio, September, 1985.
Clark, R.M.; Regli, S. A Mathematical and Statistical Analysis for the
InactivatiOn of Giordia lamblia by Free Chlorine. Submitted to the
Journal of Environmental Science Engineering, 1989.
Clark, R.; Regli, S.; Black, D. Inactivation of Glardia lanbila by Free
Chlorine: A Mathematical Model. Presented at AWWA Water Quality
Technology Conference. St. Louis, Mo., November 1988.
Cleasby, J. 1.; Hilmoe, D. J.; Dimitracopoulos, C. 3, Slow-Sand and Direct
In—Line Filtration of a Surface Water. J.AWWA, 76(12):44-55, 1984.
DeWalle, F. 8.; Engeset, J.; Lawrence, W. Removal of Giardip lamblip
Cysts by Drinking Water Plants. EPA-600/S2-84-069, United States En-
vironmental Protection Agency, MERL, Cincinnati, Ohio, May 1984.
Fox, K. R.; Miltner, P. J.; Logsdon, G. S.; flicks, 0. 1.; Drolet, L. F.
Pilot Plant Exploration of Slow Rate Filtration. Presented at the AWWA
Annual Conference Seminar, Las Vegas, Nevada, June 1983.
Fujioka, R.; Kungskulniti, N.; Nakasone, S. Evaluation of the Presence
— Absence Test for Coliforms and the Membrane Filtration Method for
Heterotrophic Bacteria. AWWA Technology Conference Proceedings, November,
1986.
Geldreich, E. Personal coiilnunication to Linda Averell, Malcolm Pirnie
Engineers, Paramus, New Jersey, July 1989.
Great Lakes—Upper Mississippi River Board of State Public Health and
Environmental Managers Comittee. Recomended Standards for Water Works ,
1987 EdItion.
HendrIcks, 0..; Al—AnI, L; Bellamy, 14.; Hibler, C.; PtElroy, J. Surrogate
Indicators for Assessing Removal of Glardla Cysts, AWWA Water Quality
Technology Conference, 1984.
Hoff, J. C. I ijctIvation of Microbial Aoents by Chemical Disinfectants .
EPA-6O0/S2..86 . 67 , U.S. Environmental Protection Agency, Water Engineer-
ing Resarcb Laboratory, Drinking Water Research Division. Cincinnati,
Ohio, Sept .r 1986.
Hoffbuhr, 3. 14.; Blair, J.; Bartleson, N..; karlln, R. Use of Particulate
Analysis for Source and Water Treatment Evaluation. AWWA Water Quality
Technology Conference ProceedIngs, November 1986.
Horn, J. B.; Hendricks, 0. W. Removals of Giardia iysts and other
Particles fr Low Turbidity Waters Using the Culligan P lt1-Tech Filtra-
-2-

-------
tion System. Engineering Research Center, Colorado State University 1
Unpub 1 i shed, 1986.
Joost, R. D.; Long, 8. W.; Jackson, L. Using Ozone as a Primary
Disinfectant for the Tucson CAP Water Treatment Plant, presented at the
lOAf PAC Ozone Conference, Monroe, M I, 1988.
Kuchta, J. M.; States, S. J.; McNanara, A. II .; Wadowsky, R. M.; Yee, R. B.
Susceptibility of Legionella neumoohilp to Chlorine in Tap Water. Appl.
Environ. Microbioh, 46(5): 1134-1139, 1983.
Letterrian, R. D. The Filtration Requirement in the Safe Drinking Water
Act Amendments of 1g86. U.S. EPAfAAAS Report, August 1986.
Logsdon, G. S.; Symons, J. N.; Hoye, Jr., R. L.; Arozarena, M. M.
Alternative Filtration Methods for Removal of Giardia Cysts and Cyst
Model. J.AWWA, 73:111-118, 1981.
Logsdon, G.; Thurman, V.; Frindt, E.; Stoecker, J. Evaluating Sedimenta-
tion and Various Filter Media for Removal of Giardia Cysts. J. AWWA,
77:2:61, 1985.
Logsdon, 6. S. Report for Visit to Carroflton, Georgia, USEPA travel
report, February 12, 1987a.
Logsdon, 6. S. Comparison of Some Filtration Processes Appropriate for
Giardia Cyst Removal. USEPA Drinking Water Research Division; Presented
at Calgary Glardia Conference, Calgary; Alberta, Canada, February 23-25,
1987b.
Long, P. L. Evaluation of Cartridge Filters for the Removal of Giardia
lamblia Cyst Models from Drinking Water Systems. J. Environ. Health,
45(5) :220-225, 1983.
Markwell, 0. 0., and Shortridge, K. F. Possible Waterborne Transmission
and Maintenance of Influenza Viruses In Domestic Ducks. Applied and
Environmental Microbiology, Vol. 43, pp. 110-116, January, 1981.
Morand, J., N.; C. R. Cobb; R. II. Clark; Richard, G. S. Package Water
Treatment Plants, Vol. 1, A performance Evaluation. EPA-600/2-80-008a,
USEPA, MERL., Cincinnati, Ohio, July 1980.
Morand, .3. H.; Young, N. J. Performance Characteristics of Package Water
Treatment Plants, Project Su ary. EPA-600/52-82-1OI, USEPA, MERL,
CIncinnat1 Ohio, March, 1983.
Moraca, P.; Stout, .3. £.; Yu, V. L. Comparative Assessment of Chlorine,
Heats Ozone, and UV Light for Killing Leglonella pneu oohila Within a
Model Pluming System. Appi. Environ. Microbial., 53(2):447-453. 1987.
Notestine, T., Hudson, .3. ClassificatIon of Drinking Water Sources as
Surface or Ground Waters. Final Project Report. Office of Environmental
-3-

-------
Health Programs. Washington Department of Social and Health Services,
August 1988.
Poynter, S. F. B.; Slade, J. S. The Removal of Viruses by Slow Sand
Filtration, Prog. Hat. Tech. Vol. 9, pp. 75—88, Perganion Press, 1971.
Printed in Great Britain.
Randall, A.D. Movement of Bacteria From a River to a Municipal Well — A
Case History. American Water Works Association Journal. Vol. 62, No. 11,
p.716-720., November 1970.
Rice, E.W.; Hoff, J.C. Inactivation of Glardia lamblia cysts by
Ultraviolet Radiation. Appi. Environ. Mlcrobiol. 42: 546-547, 1981.
Robeck, G. G; Clarke 1 N. A.; Dostal, K. A. Effect veness of Water
Treatment Processes in Virus Removal. J. AWWA, 54(1O):1275-1290, 1962.
Robson, C.; Rice, R.; Fujikawa, E.; Farver, B. Status of U.S. Drinking
Water Treatment Ozonation Systems, presented at IOA Conference, Myrtle
Beach, SC, December 1988.
Rose, J. Crvotosooridium in Water; Risk of Protozoan Waterborne Trans.
mission. Report prepared for the Office of Drinking Water, U.S. EPA,
Sumer, 1988.
Rubin, A. Factors Affecting the Inactivation of Glardla Cysts by
Monochioramine and Comparison with other Disinfectants. Water Engineering
Research Laboratory, Cincinnati, OH, March 1988a.
Rubin, A. CT Products for the Inactivation of Glardia Cysts by Chlorine,
Chiorarnine, Iodine, Ozone and Chlorine Dioxidew submitted for publication
in J. AWWA, December 1988b.
Slezak, L.; Sims, R. The Application and Effectiveness of Slou’. Sand
Filtration in the United States. J.AWWA, 76(12):38-43, 1984.
Sobsey, M. Detection and Chlorine Disinfection of Hepatitus A in Water.
CR-813-024. EPA Quarterly Report. December 1988.
Stolarik, G.; ChristIe, 0. Projection of Ozone C-T Values Los Angeles
Aqueduct Filtration Plant, 1988.
U. S. Envlrovental Protection Agency, Office of Drinking Water, Criteria
and Standards Division. Manual for Evaluating Public Drinking Water
Supplies, 1971.
U. S. Environmental Protection Agency, Office of Drinking Water. PubFic
Notification Handbook for Drinking Water Suppliers, May 1978.
U. S. Environmental Protection Agency, Office of Ground W ter Protection.
Guidelines for Applicants for State Welihead Protection Program Assistance
Funds Under the SDWA. June 1987..
—4-

-------
U. S. Environmental Protection Agency, Office of Ground Water Protection.
Guidelines for Delineation of Welihead Protection Area, June 1987b.
U. S. Environmental Protection Agency, Office of Drinking Water. Workshop
on Emerging Technologies for Drinking Water treatment, April, 1988a.
U. S. Environmental Protection Agency. Office of Drinking Water.
Technologies and Costs for the Removal of Microb;al Contaminants from
Potable Water Supplies, October, 1988b.
World Health Organization Collaborating Center. Slow Sand Filtration of
Comwnity Water Supplies in Developing Countries. Report of an Interna-
tional Appraiser Meeting, Nagpur, India, Bulletin Series 16 , September
15-19, 1980.
—5—

-------
APPENDIX A
EPA CONSENSUS METHOD
FOR GIARDIA CYST ANALYSIS

-------
TESTI\G FOR L\RJrA I\ t ATER
To beg the wo’thg’tou.p4 ov Uyi , Ja j Va . conce o. gave a LiLde pte nt t ou
abow Zhe 4Wlg mUhod uAed _ti the Re9 .or1 10 Labon atc”t j. The 6° _< . ;
page av d Appe td C 4ur,v,io.n ze h. aLta.
‘ thods of Testing for Ciartha in Water (George (Jay) Vasconcelos, Re;ional
Microbiologist, Region 10 L ibcr torv,
Manchester, ashington)
Backgro d :
Although recent development of an excystation techniqt by Drs. Bingham,
Meyer, Rice and Schaefer could in future lead to developing cultural methods,
at this time no ieliable methods exist for culturing Giartha cysts from tsater
saIT ples. At present, the only practical method for determining the presence
of cysts in water is by direct microscopic examination of sample concentrates.
Microscopic detection in water-sample concentrates isn’t an ideal process.
Finding and identifying the cysts relies allTost entirely on the training,
skill, experience and persistence of the examiner. (And it is a skill not
widespread among water-s ply laboratories.) But despite its limitations,
microscopic identification is currently the best method we have.
Years ago, the basic assi.mption was made that in order to find Giardia cysts
in water, some form of san le concentration was necessary. As early as 1956,
labs were using membrane filters with a porosity of 0.45 pin. With few exceptions,
these atter ts were t successfu1. The center for Disease Control has tried
particulate filtration, with diatomaceous earth as the meth zn. This removed
the cysts from the water, but the cysts couldn’t be separated from the
particles of diatomaceous earth.
With the recent increase in the incidence of waterborne giard.iasis, further
efforts have been made to improve the detec;ion method. An ideal method t ould
be one that recovers all cysts in a water sample rapidly, cheaply and simply;
allows rapid detection, identification and quantification; and provides
information on the viability of and/or infectivity potential of cysts detected.
Unforttmately, no such method exists. The methods presently available
can be broadly separated into two general stages: primary concentration and
processing (see Table 1 on next page), and detection and identification
(see Table 2 on next page).
(14

-------
TESTING FOR IN VATER
Methods of Testing for Giardia in Water (Contini. d... )
Ching I tiNier
uSPHS . 19 6
Py er , Du rair £ Henry Eng
198 . (unpubliihe@)
Shaw cc al. 1977
Jur.n 7 ,T979
llcl.in at ii . 1983
DM145. Was h In gton
Brewer, Wright State UN.
(unpublished)
Riggs, CONS Lab, Ierhiey. CA
(unpubi lined)
Jahubowihi. Erickson, 1979 £
1980, £PA—C ncthnatt
MilliDore Corp.
(unpubi lined)
DuWalie. U. of Wash., 1982
(unpubi lined)
Recovery 3.151
ExtractIon iv ,. 58%
May be u tful for
processing filter
washings
Claiws 7 5% recovery
frsu orion filters
METhOD
1. I ujnofiuoreiceA
CFA
T’DLE 2: DETECTION METHODS
15)
IFA
Movotlonil Antibodies
2. ELISA Yecrioe
3, 9rtgt ieid/PriaIt Contrast
Saudi. (PA.ClndtMatt
Riggs. CSDS
Riggs. CSOMS
Sauch. EPA.CthdinfiStl
(unpuDli shed)
Manger, J. Hopkins liD, 1983
EPA Consensus .ithOd
Still v der Study
Still sander Stuay
Feces saiiplei only
Ongoing
TAILE 1: IMARY CONCENTRATION AND PROCESSING METHODS
METHOD INVESTIGATOR (5 )
1. Menbrarie Filtration
Cellulosic
( 47 .Q.45 )
Po lycarbinate
(293 .5um)
2. Pirticulate Filtration
(diatooac eous eartn, said,
etc.)
3. Algae (Foertt) Centrifuge
4, Anionic and Cationic
Encrunce e 5%fl$
S. Epo’y -Fibergluss Balston
hoe
6. MicropOrous Var, Ovin Depth.
1 tern
(7 £ 1u orion I polyprolylene)
7. Pellicin Cassette Systen
8. Filterwas ing Apparatus
RE S IJLTS
Generally unsucesiful
Passing 1 gallsin 0
10 PSI. 15-1800 g l
total.
Generally good resovul
but poor •l ati n
Good rapid recovery.
but haited In field
use.
Generally sansucesiful
Onerall recovery 20—801
INVESTIGATORS(H
Riggs. CSDHS Lab. Serkley. CA
1983
RESULTS
Good prep.. Cross Re

-------
TESTING FOR GIARDI .\ IN WATER
t ethods of Testing for in Water (Continued... )
Copies of Table 1 and Table 2 are also shown in Appendix C, along with
further detail about the method.s.
EPA Consensus ‘ thod :
In Septei er, 1980, the EPA convened a workshop on Giard.ia methodology in
Cincinnati. Its main purpose was to identify the best available methodology,
and to agree on a referer.ce method. The five labs in attendance recognized
that any proposed method would be based in large part on opinions and personal
preferences rather than on hard data, but that agreeing on a consensus metnoc
would promote 1. uforTru.ty and provide a basis for future comparisons. Our
lab has modified the EPA consensus method slightly for our use. This method
is outlined below.
Filter t wotzid into quarters
Rinsed in distilled water with polysorbate 20
Settled overnight, or centrifuged
Collect sediment and add 2% Formaldehyde in PBS
.11’
Settled overnight, or centrifuged
1
Collect sediment
4,
lg. (1g.
4,
Sucrose or
Percoll-sucrose ZnSO 4 Flotation
gradient
Microscopic observation of the entire
concentrate (Brightiield/Phase-contrast)

-------
APPENDIX B
NSTITtJTIONAL CONTROL OF LECIONTLLA

-------
APPENDIX B
INSTITt’TICNAL COW ROL OF LEGIONELLA
Introduction
Legionella is a genus name for bacteria comz nly found in lake and river
waters. Some species of this genus have been identified as the cause of the
disease legionellosis. In particular, Legionella pneumo hi1a has been
identified as the cause of Legionnaires disease, the pneumonia form of
legionellosis and with Pontiac Fever, a nonpneuscnia disease. Outbreaks of
legionellosis are primarily associated with inhalation of water aerosols or,
less c only, with drinking water containing Legionella bacteria w th
specific virulence factors not yet identified. Foodborne outbreaks have not
been reported CUSEPA, 1985).
As discussed in this document, treatment requirements for disinfection of
a municipal water supply are thought to provide at least a 3 log reduction of
Legionella bacteria (see Section 3.2.2). However, some recontam1.nation may
occur in the distribution system due to cross connections and during
installation and repair of water mains. It has been hypothesized that the low
concentrations of Legionelia entering buildings due to these sources may
colonize and regrow in hot water systems (USEPA, 1985). Although all of the
criteria required for colonization are not known, large institutions, such as
hospitals, hotels, and public buildings with recirculating hot water systerts
seem to be the most susceptible. The control of Legionella in health care
institutions, such as hospitals, is particularly important due to the
increased susceptibility of many of the paients.
The colonization and growth of Legionella in drinking water primarily
occurs within the consumer’s plumbing systems after the water leaves the
distribution system. Therefore, the control of these organisms must be the
consumer’s responsibility. Thu appendix is intended to provide guidance to
these institutions for the detection and control of the Legionella bacteria.
Monitoring
It is suggested that hospLtals, and other institutions with potential for
the growth of Legioneila , conduct routine monitoring of their hot water
B—i

-------
systems at least quarterly. (1) The analytical procedures for the detection cf
these organisms can be found in Section 912.1 “ Leg ionellaceae of the 1.6th
edition of Standard Methods . Samples should be taken at, or closely
following, the hot water storage reservoir and from a rner of shower heads.
It is recosmended that showers with the least frequent usage be included in
the sampling program. Follow—up testing is suggested for all positive
indications prior to the initiation of any remedial measures. If the the
presence of Leg2onella is confirmed, then remedial measures should be taken.
Although the reqrowth of Legionella is conly associated with hot water
systems, hot and cold water interconnections may provide a pathway for cross
contamination. For this reason, systems detecting Legionella in hot water
systems should also monitor their cold water systems.
Ire atment
Because the primary route of exposure to Legionella is probably
inhalation, rather than inge tion, it is recoended that disinfection
prcedt r include an initial shock treatment period to disinfect shower heads
and hot water taps where the bacteria may colonize and later become airborne.
The shock treatment period should also include disinfection of hot water
tanks. After this time, a point-of entry treatment system can be installed to
provide continual disinfection of the hot water system.
Initial Disinfection
The most applicable method for the initial disinfection of shower heads
and water taps is heat eradication. The fittings can be removed and held at
temperatures greater than 60 C for at lea t 24 hours. Disinfection of f it—
tings can also be achieved by soaking or rinsing with a strong chlorine
solution. When soaking the fittings, a minimt chlorine strength of 50 mg/L
should be aced for a period of no less than 3 hours. Rinsing with chlorine
should be performed with more concentrated solutions. Care most be taken not
1. Monitoring frequency based on the reported rate of Legionella
reqrc,wth observed during disinfection studies (USEPA, 1985).
8—2

-------
to corrode the finished surface on the fittings. Coemerciafly available
bleaches, for example, are typically 5.25 percent chlorine by weight.
Long—Term Disinfection
Heat — Numerous studies have shown that increasing the hot water tempera-
ture to 50 — 70 C over a period of several hours may help to reduce and
inhibit Legionella populations. However, some instances of regrowth after 3
to 6 months have been reported. In these cases, the authors have concluded
that a periodic schedule of short—term temperature elevation in the hot water
may be an effective control against legionellosis (USEPA, 1985; Muraca, 1986).
Disinfection by this method also requires periodic flushing of faucets and
shower heads with hot water. Although heat eradication is easily implemented
and relatively inexpensive, a disadvantage is the potential need for periodic
disinfection. The potential for scalding from the unusually hot water also
exists (USEPA, 1985; Muraca, et al. 1986).
Chlorination — Several studies have suggested that a free chlorine
residual of 4 /L will eradicate Legionella growth. There is, however, a
possibility for recontamination in areas of the system where the chlorine
residual drops below this level. A stringent monitoring program is therefore
required to ensure that the proper residual is maintained throughout the
system and under varying flow conditions. It may also be necessary to apply a
large initial chlorine dose to maintain the 4 mg/L residual. This may cause
problems of pipe corrosion and, depending on water quality, high levels of
trihalomethanes (I RMa).
Ozone — Ozone is the st powerful oxidant used in the potable water
industry. One study indicated that an ozona dosage of 1 to 2 mg/L was suffi-
cient to provide a S log reduction of . !L1a (Muraca, et al. 1986). Ozone
is generated by passing a high voltage current of electricity through a stream
of dry air or oxygen. The use of high voltage electricity requires proper
handling to avoid creating hazardous conditions. The ozone is applied by
bubbling the ozone containing gas through the water in a chamber called a
contactor.
One of the disadvantages of this system is its complexity. It requires a
dry sir or oxygen source, a qeneratof, and a contactor sized to provide 2 to 5
minutes of contact time and an ambient ozone monitor. All materials in
B- 3

-------
contact with the ozone must be constructed of special ozone resistant nat—
erials to prevent leakage. Leak detection is also required because of the
toxic nature of ozone and possible explosive conditions if pure oxygen is used
for generation.
Mother disadvantage of ozonation is the rapid decomposition of ozone
residuals. The half-Life of ozone in drinking water is typically around 10
minutes. This makes it difficult, if not impossible, to maintain a residual
throughout the water system and may require the use of a supplementary
disinfectant such as chlorine or heat. For these reasons it is not thought
that ozoriation is viable for institutional applications.
Ultraviolet Irradiation — Ultraviolet (UV) Light, in the 254 nanometer
wavelength range can be used as a disinfectant. UV systems typically contain
low—pressure mercury vapor lamps to maximize output in the 254 nm range.
water entering the uzu.t passes through a clear cylinder while the lamp is on,
exposing bacteria to the UV light. Because liv light can not pass through
ordinary window glass, special glass or quartz sleeves are used to assure
adequate exposure.
The intensity of liv irradiation is measured in microwatt-seconds per
sq uare centimeter (uW—s/cm2). Several studies have shown a 90 percent reduc-
tion of Legionella with a liv dosage of 1000 — 3000 uW—i/cm2, compared to 2000
to 5000 uW—s/cm2 for E. coil, Salmonella and Pseudomonas (USEPA, 1985). In
another study, a 5 log reduction of LeqioneUa was achieved at 30,000
uW-s/c2: and the reduction was more rapid than with both ozone and chlorine
disinfection (Huraca, et al. 1986).
The ma)or advantage of liv disinfectic n is that it does not require the
addition of chemicals. This eliminates the storage and feed problems associ-
ated with the use of chlorine, chlorine dioxide and chioramines. In addition,
the only I %A 4 ,Itenance required is periodic cleaning of the quartz sleeve and
replacement of bulbs. VV monitors are available which measure the light
intensity reaching the water and provide, a signal to the user when
maintenance is required. These monitors are strongly suggested for any
application of liv irradiation for disinfection. It should be noted, however,
that these monitors measure light intensity which may not be directly related
to disinfection efficiency. The vv lamps should therefore not be operated
past the manufacturers use rating even with a continuous Uv monitor installed.
B-4

-------
Mother disadvantage of LW disinfection, as with ozonatton, is that a
res idual. is not provided. A supplementary disinfectant may therefore be
required to provide protection throughout the system. In addition, turbidity
may interfere with LW disinfection by blocking the passage of light to the
microorganisms.
Other Control Methods — In addition to chemical and heat disinfection.
there are system modifications which can be made to inhibit LegLortella growth.
Many institutions have large hot water tanks heated by coils located midway in
the tank. This type of de5ign may result in areas near the bottom of the tank
which are not hot enough to kill Legionella . Designing tanks for more even
distribution of heat may help limit bacterial colonization. In addition.
sediment build-up in the bottom of storage tanks provides a surface for
colonization. Periodic draining and cleaning may therefore help control
growth. Additionally, other studies have found that hot water systems with
stand—by hot water tanks used for meeting peak demands, still tested positive
for Legionella despite using elevated temperature (55 C) and chlorination
(2 p ) (Fisher—Koch, et al. 1984.) Stringent procedures for the cleaning,
disinfection and monitoring of these stagnant tanks should be set up and
followed on a regular basis.
In another study, it was reported that black rubber washers and gaskets
supported Legionella growth by providing habitats protected from heat and
chlorine. It was found, after replacement of the black rubber washers with
Proteus 80 compound washers, that it was not possible to detect Legionella
from any of the fixtures (Colbourne, et al. 1984).
Conclusions
Legionella bacteria have bean identified as the cause of the disease
legionellosi., of which the most serious form is Legionnaires Disease.
Although conventional water treatment practices are sufficient to provide
disinfection of Legionella , regrowth in buildings with large hot water
heaters, and especially with recirculating hot water systems, is a significant
problem. This problem is of particular concern to health care institutions,
such as hospitals, where patients may be more susceptible to the disease. -
a—s

-------
This guideline suggests a program of quarterly monitori g for L.egionella .
If the monitoring program suggests a potential problem with these organisms • a
two stage disinfection program is suggested consisting of an initial period of
shock treatment followed by long term disinfection.
Four methods of disinfection for the control of Legionella were presented
in this appendix; heat, chlorination, ozonation, and ultraviolet irradiation.
All four of the methods have proven effective in killing Legionella .
Ultraviolet irradiation and heat eradication are the suggested methods of
disinfection due, primarily, to advantages in monitoring and maintenance.
However, site specific factors nay make chlorination or ozonation more feas-
ible for certain applications. In addition, it is recommended that all
outlets, fixtures and shower heads be inspected and all black rubber washers
and gaskets replaced with materials which do not support the growth of
Legionella organisms.
One problem associated with the application of point-of—entry treatment
systems is the lack of an approved program for certifying performance claims.
However, the National Sanitation Foundation (NSF’, Ann Arbor, MI an
unofficial, non—profit organization, does have a testing program to verify
disinfection efficiencies and materials of construction. Certification by the
NSF, or other equivalent organizations, is desirable when selecting a
treatment system.
References
Cothourne, J.; Smith, M. C.; Fisher—Koch, S. P. and Harper, D. Source of
Leq .one1la pneumophila Infection in a Hospital Hot Water Systemt Materials
Used in Water Fittings Capable of Supporting I.. pneumophila Growth. In
ThornBberry, C..; Balows. A.; Feeley, .7. C. and akubowski, W. Legionella —
Proceedings of the 2nd InternationaL Symposium. American Society for
Microbiology, pp. 305—307, 1984.
Fisher—Koch, S. P.; Smith, M.G.; Harper. D. and Colbourne, 7. Source of
Legioneila pneumonia in a Hospital Sot Water System, pp. 302—304 in
Thornsberry, C.; Belays, A.; Feeley, J.C. and J&kubowski, W.
Proceedings of the 2nd International Symposium, American Socicty for
MicrobioLogy, pp. 302—304, 1984.
B—6

-------
APPE\DIX C
CO; CENTR 1 \TINC, PROCESSING. DETECTING A D IDENTIFYING
GT. RflT CYSTS IN A ER
The 60! o .Ln9 page s con tai.n bacIzg’Lo ind £n60 t.con ppo’t ,..ng
Jay Va4concee04 t zLk, “Me thodo c Te t . ng 04 O .a d4a u1 Wate .”
PZeaAe 6ee he ia y 06 .th .4 aZIz (pp.74 &tot cth 76) 6o/t £c& t.the’.
n6o&maton 1 and 6on. an outL’ ..ne 06 .tke. modi6 ed EPA Con en4
Method.

-------
APPENDIX C
DETERMINATION OF DISINFECTANT CONTACT TIME
As indicated in Section 3, for pipelines, J.! fluid passing through
the pipe is assumed to have a detention time equal to the theoretical or
mean residence time at a particular flow rate. However, in mixing basins,
storage reservoirs, and other treatment plant process units, utilities
will be required to determine the contact time for the calculation of CT
through tracer studies or other methods approved by the Primacy Agency.
For the purpose of determining compliance with the disinfection
requirements of the SWTR, the contact time of mixing basins and storage
reservoirs used in calculating CT should be the detention time at which
90 percent of the water passing through the init is retained within the
basin. This detention time was designated as I according to the
convention adopted by Thirumurthi (1969). A profile of the flow through
the basin over time can be generated by tracer studies. Information
pr vide 1 by these studies is used for estimating the detention time, T .
for the purpose of calculating CT.
This appendix is divided into two sections. The first section
presents a brief synopsis of tracer study methods, procedures, and data
evaluation. In addition, examples are presented for conducting hypo-
thetical tracer studies to determine the T contact time in a clearwell.
The second section presents a method of determining T from theoretical
detention times In systems where it is impractical to conduct tracer
studies.
C.1 Tracer Studies
C.1.1 Flow conditions
Although detention time is proportional to flow, it is not generally
a linear function. Therefore, tracer studies are needed to establish
detention times for the range of flow rates experienced within each
disinfectant section.
As discussed in Section 3.2, a single flow rate may not characterize
the flow through the entire system. With a series of reservoirs,
C-’

-------
clearweHs, and storage tanks flow will vary between each portion of the
system.
In filter plants, the plant flow is relatively uniform from the
intake through the filters. An increase or reduction in the intake
pumping capacity will impart a proportional change in flow through each
process unit prior to and including the filters. Therefore, at a constant
intake pumping rate flow vanations between disinfectant sections within
a treatment plant, excluding clearwells, are likely to be small, and the
the design capacity of the plant, or plant flow, can be considered the
nominal flow rate through each individual process unit within the plant.
Clearwells may operate at a different flow rate than the rest of the
plant, depending on the pumping capacity.
Ideally, tracer tests should be performed for at least four flow
rates that span the entire range of flow for the section being tested.
The flow rates should be separated by approximately equal intervals to
span the range of operation, with one near average flow, two greater than
average, and one less t’ av average flow. The flows should also be
selected so that the highest test flow rate isat leaste 91 percent of the
highest flow rate expected to ever occur in that section. Four data
points will assure a good definition of the section’s hydraulic profile.
The results of the tracer tests performed for different flow rates
should be used to generate plots of T 10 vs. Q for each section in the
system. A smooth line is drawn through the points on each graph to create
a curve from which T may be read for the corresponding Q at peak hourly
flow conditions. This procedure is presented In Section C.1.8.
It may not be practical for all systems to conduct studies at four
flow rates. The number of tracer tests that are practical to conduct is
dependent on site-specific restrictions and resources available to the
system. Systems with limited resources can conduct a minimum of one
tracer test for each disinfectant section at a flow rate of not less than
91 percent of the highest flow rate experienced at that section. If only
one tracer test Is performed, the detention time determined by the test
may be used to provide a conservative estimate in CT calculations for that
:::tlon for all flow rates less than or equal to the tracer test flow
C-2

-------
rate. is inverseix proportional to flow rate, therefore, the T 10 at a
flow rate other than that which the tracer study was conducted (T ) can
be determined by multiplying the from the tracer study ( T jor) by the
ratio of the tracer study flow rate to the desired flow rate, i.e.,
= Tj3 X where
at system flow rate
= at tracer flow rate
= tracer study flow rate
= system flow rate
The most accurate tracer test results are obtained when flow is
constant through the section during the course of the test. Therefore,
the tracer study should be conducted at a constant flow whenever
practical. For a treatment plant consisting of two or more equivalent
process trains, a constant flow tracer test can be performed on a section
of the plant by holding the flow through one of the trains constant while
operating the parallel train(s) to absorl, any flow variations. Flow
variations during tracer tests in systems without parallel trains or with
single clearwells and storage reservoirs are more difficult to avoid. In
these instances, T LQ should be recorded at the average flow rate over the
course of the test.
C.1.2 Other Traceri3tudy Considerations
In addition to flow conditions, detention times determined by tracer
studies are dependent on the water level in the contact basin. This is
particularly pertinent to storage tanks, reservoirs, and clearwel Is which,
in addition to being contact basins for disinfection are also often used
as equalization storage for distribution system demands. In such
instances, the water levels in the reservoirs vary to meet the system
demands. The actual detention time of these contact basins will also vary
depending on whether they are emptying or filling.
For some process units, especially sedimentation basins which are
operated at a near constant level, that Is, flow In equals flow out, the
detention time determined by tracer tests is valid for calculating CT when
C-3

-------
the basin is operating at water levels greater than or equal to the level
at which the test was performed. If the water level during testing is
higher than the normal operating level, the resulting concentration
profile will predict an erroneously high detention time. Conversely 1
extremely low water levels during testing may lead to an overly conserva-
tive detention time. Therefore 1 when conducting a tracer study to
determine the detention time, a water level at or slightly below, but not
above, the normal minimum operating level is recorirended.
For many plants, the water level in a clearwell or storage tank
varies between high and low levels in response to distribution system
demands. In such instances, in order to obtain a conservative estimate
of the contact time, the tracer study should be conducted during a period
when the tank level is falling (flow out greater than flow in). This
procedure wfll provide a detention time for the contact basin which is
also valid when the water level is rising (flow out less than flow in)
from a level which is at or above the level when the was determined by
the tracer study. Whether the water level is constant or vari3 le, the
tracer study for each section should be repeated for several different
flows, as described in the previous section.
For clearwells which are operated with extreme variations in water
level, maintaining a CT to comply with inactivation requirements may be
impractical. Under such operating conditions, a reliable detention time
is not provided for disimfection. However, the system may install a weir
to ensure a minimum water level and provide a reliable detention time.
Systems comprised of storage reservoirs that experience seasonal
variations in water levels may perform tracer studies during the various
seasonal conditions. For these systems, tracer tests should be conducted
at several flow rates and representative water levels that occur for each
seasonal ca dition. The results of these tests can be used to develop
hydraulic profiles of the reservoir for each water level. These profiles
can be plotted on the same axis of T 10 vs. Q and may be used for calculat•
img CT for different water levels and flow rates.
Detention time may also be Influenced by differences in water
temperature within the system. For plants with potential for thermal
C-4

-------
stratification, additional tracer studies are suggested under the various
seasonal conditions which are likely to occur. The contact times
determined by the tracer studies under the various seasonal conditions
should remain valid as long as no physical changes are made to the mixing
basin(s) or storage reservoir(s).
As defined in Section 3.2.2, the portion of the system with a
neasurable tontact time between two points of disinfection or residual
monitoring is referred to as a section. For systems which apply
disinfectant(s) at more than one point, or choose to profile the residual
from one point of application, tracer studies should be conducted to
determine T 10 for each section containing process unit(s). The T for a
section may or may not include a length of pipe ard is used along with the
residual disinfectant concentration prior to the next disinfectant appli-
cation or monitoring point to determine the CT ajc for that section. The
inactivation ratio for the section is then determined. The total
inactivation and log inactivation achieved in the system can then be
determined by sunrino the inactivation ratios for all sections as
explained in Section 3.2.2.
For systems that have two or more units of identical size and
configuration, tracer studies only need to be conducted on one of the
units. The resulting graph of T 13 vs. flow can be used to determine T 10
for all identical units.
Systems with more than one section in the treatment plant may
determine T 19 for each section
— by individual tracer studies through each section, or
- by one tracer study across the system
If possible, tracer studies should be conducted on each section to
determine the T 10 for each section. In order to minimize the time needed
to conduct studies on each section, the tracer studies should be started
at the last section of the treatment train prior to the first customer and
completed with the first section of the system. Conducting the tracer
studies in this order will prevent the interference of residual trac!r
material with subsequent studies.
C-5

-------
However, it may not always be practical for systems to conduct
tracer studies for each section because of time and manpower constra rits.
In these cases, one tracer study may be used to determine the T 10 values
for all of the sections at one flow rate. this procedure involves the
following steps:
1. Add tracer at the beginning of the furthest upstream
disinfection section.
2. Measure the tracer concentration at the end of each disinfec-
tion section.
3. Determine the T 10 to each monitoring point as outlined in the
data evaluation examples presented in Section C.1.7.
4. Subtract values of each of the upstream sections from the
overall t 10 value to determine the T of each downstream
section.
This approach is valid for a series of two or more consecutive
sections as long as all process units within the sections experience the
same flow condition. This approacn is illustrated by Hudson (1975) in
which step-dose tracer tests were employed to evaluate the baffling
characteristics of flocculators and settling basins at six water treatment
plants. At one plant, tracer chemical was added to the rapid mix, which
represented the beginning of the furthest upstream disinfection section
in the system. Samples were collected from the flocculator and settling
basin outlets and analyzed to determine the residence-time characteristics
for each section. Tracer measurements at the flocculator outlet indicated
an approximate T 10 of 5 minutes through the rapid mix, interbasin piping
and flocculator. Based on tracer concentration monitoring at the settling
basin outlet, an approxImate 110 of 70 minutes was determined for the
combined sections, including the rapid mix, interbasin piping, floccu-
lator, and settling basin. The flocculator of 5 minutes was subtracted
from the c tned sections’ T 10 of 70 mInutes, to determine the T 10 for the
settling basin alone, 65 minutes.
This approach may also be applied in cases where disinfectant
application and/or residual monitoring iS discontinued at any point
C-6

-------
between two or more sections with known values. These T values may
be sumed to obtain an equivalent T 10 for the combined sections.
For ozone contactors, flocculators or any basin containing mixing,
tracer studies should be conducted for the range of mixing used in the
process. In ozone contactors, air or oxygen should be added in lieu of
ozone to prevent degradation of the tracer. The flow rate of air or
oxygen used for the contactor should be applied during the study to
simulate actual operation. Tracer studies should then be conducted at
several airfoxygen to water ratios to provide data for the complete range
of ratios used at the plant. For flocculators, tracer studies should be
conducted for various mixing intensities to provide data for the complete
range of operations.
C.1.3 Tracer itudv Methods
This section discusses the two most co on methods of tracer
addition employed in water treatment evaluations, the step-dose method
and the slug-dose method. Tracer study methods involve “ appli:ation
of chemical dosages to a system and tracking the resulting effluent
concentration as a function of time. The effluent concentration profile
is evaluated to determine the detention time, T 10 .
While both tracer test methods can use the same tracer materials and
involve measuring the concentration of tracer with time, each has distinct
advantages and disadvantages with respect to tracer addition procedures
and analysis of results.
The step-dose method entails introduction of a tracer chemical at
a constant dosage until the concentration at the desired end point reaches
a steady-state level. Step-dose tracer studies are frequently employed
in drinking water applications for the following reasons:
— the resulting normalized concentration vs. time profile is
directly used to determine, T . the detention time required
for calculating CT
— very often, the necessary feed equipment is available to
provide a constant rate of application of the tracer chemical
c - I

-------
One other advantage of the step-dose method is that the data may be
verified by comparing the concentration versus elapsed time profile for
samples collected at the start of dosing with the profile obtained when
the tracer feed is discontinued.
Alternatively, with the slug-dose method, a large instantaneous dose
of tracer is added to the incoming water and samples are taken at the exit
of the unit over time as the tracer passes through the unit. A disadvan-
tage of this technique is that very concentrated solutions are needed for
the dose in order to adequately define the concentration versus time
profile. Intensive mixing is therefore required to minimize potential
density-current effects and to obtain a uniform distribution of the
instantaneous tracer dose across the basin. This is inherently difficult
under water flow conditions often existing at inlets to basins. Other
disadvantages of using the slug—dose method include:
- the concentration and volume of the instantaneous tracer dose
must be carefully computed to provide an adequate tracer
profile at the effluent of the basin
- the resulting concentration vs. time profile cannot be used
to directly determine T without further manipulation
— a mass balance on the treatment section is required to
determine whether the tracer was completely recovered
One advantage of this method is that it may be applied where
chemical feed equipment is not available at the desired point of addition,
or where the equipment available does not have the capacity to provide the
necessary concentration of the chosen tracer chemical. Although, in
general, the step-dose procedure offers the greatest simplicity, both
methods are theoretically equivalent for determining T 10 . Either method
is acceptable for conducting drinking water tracer studies, and the choice
of the thod may be determined by site-specific constraints or the
system 1 s experience.
C.1.4 Tracer Selection
An Important step in any tracer study is the selection of a chemical
to be used as the tracer. Ideally, the selected tracer chemic :hc )d
be readily available, conservative (that is, not consumed or removed
c-a

-------
during treatment), easily monitored, and acceptable for use in potable
water supplies. Historically, many chemicals have been used in tracer
studies that do not satisfy all of these criteria, including potassium
permanganate, alum, chlorine, and sodium carbonate. However, chloride and
fluoride are the most convnon tracer chemicals employed in drinking water
plants that are nontoxic and approved for potable water use. Rhodamine
WI can be used as a fluorescent tracer in water flow studies in accordance
with the following guidelines:
— Raw water concentrations should be limited to a maximum
concentration of 10 mg/L.
- Drinking water concentations should not exceed 0.1 ug/L.
- Studies which results in human exposure to the dye must be
brief and infrequent.
- Concentrations as low as 2 ug/L can be used in tracer studies
because of the low detection level in the range of 0.1 to 0.2
ug/L.
The use of Rhodamire B as a tracer in water flow studies is not recom-
mended by the EPA.
The choice of a tracer chemical can be made based, in part, on the
selected dosing method and also on the availability of chemical feeding
equipment. For example, the high density of concentrated salt solutions
and their potential for inducing density currents, usually precludes
chloride and fluoride as the selected chemical for slug-dose tracer tests.
Fluoride can be a convenient tracer chemical for step-dose tracer
tests of clearwells because it is frequently applied for finished water
treatment. However, when fluoride is used in tracer tests on clarifiers,
allowances should be made for fluoride that is absorbed on floc and
settles out of water (Hudson, 1915). Additional considerations when using
fluoride in tracer studies include:
— It Is difficult to detect at low levels
sany states impose a finished water limitation of I mg/I.
- the federal secondary and primary drinking water
standards (MCLs) for fluoride are 2 and 4 mg/I,
respectively
c-9

-------
The use of fluoride is only reconinended in cases where the feed equipment
s already in place for safety reasons.
In instances where Only one of two or more parallel units is tested,
flow from the other units would dilute the tracer concentration prior to
leaving the plant and entering the distribution system. Therefore, the
impact of drinking water standards on the use of fluoride and other tracer
chemicals can be alleviated in some cases.
C.l..5 tracer Addition
The tracer chemical should be added at the same point(s) in the
treatment train as the disinfectant to be used in the CT calculations.
C.1.5.1 SteD-dose Method
The duration of tracer addition is dependent on the volume of the
basin, and hence, its theoretical detention time. In order to approach
a steady-state concentration in the water exiting the basin, tracer
addition and sampling should usually be continued for a period of two to
three times the theoretical detention time (Hudson, 1981). It is not
necessary to reach a steady state concentration in the exiting water to
determine T , however, it is necessary to determine tracer recovery, it
is recomended that the tracer recovery be determined to identify
hydraulic characteristics or density problems.
In all cases, the tracer chemical should be dosed in sufficient
concentration to easHy monitor a residual at the basin outlet throughout
the test. The required tracer chemical concentration, is generally depen-
dent upon the nature of the chosen tracer chemical 1 including its
background concentration, and the mixing characteristics of the basin to
be tested. Reco eeded chloride doses on the order of 20 mg/L (Hudson,
1975) should be used for step-method tracer studies where the background
chloride level Is less than 10 mg/I. Also, fluoride concentrations as low
as 1.0 to 1.5 mg/L are practical when the raw water fluoride level is not
significant (Hudson, 1975). However, tracer studies conducted on systems
suffering from serious shortcircuiting of flow may require substantially
c-to

-------
larger step-doses. This would be necessary to detect the tracer chemical
and to adequately define the effluent tracer concentration profile.
C.1.5.2 Slug-dose Method
The duration of tracer measurements using the slug-dose method is
also dependent on the volume of the basin, and hence, its theoretical
detention time. In general, samples should be collected for at least
twice the basin ’s theoretical detention time, or until tracer concentra—
tions are detected near background levels.
Tracer addition for slug-dose method tests should be instantaneous
and provide uniformly mixed distribution of the chemical. Tracer addition
is considered instantaneous if the dosing time does not exceed 2 percent
of the basin’s theoretical detention time (Marske and Boyle, 1973). One
recon nended procedure for achieving instantaneous tracer dosing is to
apply the chemical by gravity flow through a funnel and hose apparatus.
This method is also beneficial because it provides a means of standardiza-
tion, which is necessary to obtain reproducible results.
The mass of tracer chemical to be added is determined by the desired
theoretical concentration and basin size. Since the mass of tracer added
in slug-dose tracer tests should be the minimum mass needed to obtain
detectable residual measurements to generate a concentration profile. As
a guideline, the theoretical concentration for the slug-dose method should
be conparable to the constant dose applied in step-dose tracer tests,
i.e., 10 to 20 mg/L and 1 to 2 mg/L for chloride and fluoride, respective-
ly. The mass of tracer chemical is calculated by multiplying the
theoretical concentration by the total basin volume. This quantity is
diluted as required to apply an instantameous dose, and minimize density
effects,
c-Il

-------
C.L6 Test Procedure
In preparation for beginning a tracer study 1 the raw water
background concentration of the chosen tracer chenncal must be estab-
lished. The background concentration is essential, not only for aiding
in the selection of the tracer dosage, but also to facilitate proper
evaluation of the data.
The background tracer concentration should be determined by
monitoring for the tracer chemical prior to beginning the test. The
sampling point(s) for the pre-tracer study mon oring should be the same
as the points to be used for residual monitoring to determine CT values.
The monitoring procedure is outlined in the following steps:
- If the tracer chemical is normally added for treatment,
discontinue its addition to the water in sufficient time to
perntit the tracer concentration to recede to its background
level before the test is begun.
- Prior to the start of the test, regardless of whether the
chosen tracer material is a treatment chemical, the tracer
concentration in the water is monitored at the sampling point
where the uisinfectant residual will be measured for CT
calculations.
- If a background tracer concentration is detected, monitor it
until a constant concentration, at or below the raw water
background level is achieved. This measured concentration is
the baseline tracer concentration.
Following the determination of the tracer dosage, feed and monitoring
point(s), and a baseline tracer concentration, tracer testing can begin.
Equal sampling intervals, as could be obtained from automatic
sampling, are not required for either tracer study method. However, using
equal sample intervals for the slug-dose method can simplify the analysis
of the data. During testing, the time and tracer residual of each
measurement should also be recorded on a data sheet. In addition, the
water level, flow, and temperature should be recorded during the test.
C.h6.1 Step-dose Method
At time zero, the tracer chemical feed will be started and left at
a constant rate for the duration of the test. Over the course of the
test, the tracer residual should be monitored at the required sampling
C- 12

-------
point(s) at a frequency determined by the overall detention time and site
specific considerations. As a general guideline, sampling at intervals
of 2 to 5 minutes should provide data for a well—defined plot of tracer
concentration vs time. Less frequent residual monitoring may be possible
until a change in residual concentration is first detected. As a
guideline, in systems with a theoretical detention time greater than 4
hours, sampling may be conducted every 10 minutes for the first 30
minutes, or until a tracer concentration above the baseline level is first
detected. In general, shorter sampling intervals enable better character-
ization of concentration changes; therefore, sampling should be conducted
at 2 to 5-minute intervals from the time that a concentration change is
first observed until the residual concentration reaches a steady-state
value. A reasonable sampling interval should be chosen based on the
overall detention time of the unit being tested.
If verification of the test is desired, the tracer feed should be
discontinued, and the receding tracer concentration at the effluent should
be monitored at the same frequency until tracer concentrat 4 ons correspond-
ing to the background level are detected. The time at which tracer feed
is stopped is time zero for the receding tracer test and must be noted.
The receding racer test will provide a replicate set of measurements which
can be compared with data derived from the rising tracer concentration
versus time curve. For systems which currently feed the tracer chemical,
the receding curve may be generated from the time the feed is turned off
to determine the background concentration level.
C.1.6.2 Slug-dose Method
At time zero for the slug—dose method, a large instantaneous dose
of tracer will be added to the Influent of the unit. The same sampling
locations and frequencies described for step-dose method tests also apply
to slug-dose method tracer studies. One exception with this method is
that the tracer concentration profile will not equilibrate to a steady
state concentration. Because of this, the tracer should be monitored
frequently enough to ensure acquisition of data needed to identify the
peak tracer concentration.
C-13

-------
Slug—dose method tests should be checked by performing a mater al
balance to ensure that afl of the tracer fed is recovered, or, mass
applied equals mass discharged.
C.1.7 Data Evaluation
Data from tracer studies should be suninarized in tables of time and
residual concentration. These data are then analyzed to determine the
detention time, to be used in calculating CT. Tracer test data from
either the step or slug-dose method can be evaluated graphically,
numerically, or by a combination of these techniques.
C.1.7.1 Steo-dose Method
The graphical method of evaluating step-dose test data involves
plotting a graph of dimensionless concentration versus time and reading
the value for 110 directly from the graph at the appropriate dimensionless
concentration. Alternatively, the data from step-dose tracer studies may
be evaluated numerically by developing a semi-logarithmic plot of the
dimensionless data. The semi-logarithmic plot allows a straight li’ to
be drawn through the data. The resulting equation of the line is used to
calculate the T va1ue, assuming that the correlation coefficient
indicates a good statistical fit (0.9 or above). Scattered data points
from step-dose tracer tests are discredited by drawing a smooth curve
through the data.
An illustration of the I determination will be presented in an
example of the data evaluation °equired for a clearwell tracer study.
C.1.1.2 Slug-dose Method
Data from slug-dose tracer tests is analyzed by converting it to the
mathematically equivalent step-dose data and using techniques discussed
in Section C.1.1.1 to determine T 10 . A graph of dimensionless concentra-
tion versus time should be drawn which represents the results of a
slug-dose tracer test. The key to converting between the data forms is
obtaining the total area under the slug-dose data curve. This area is
found by graphically or numerically lntergrating the curve. The
conversion to step—dose data Is then completed In several mathematical
steps involving the total area.
C- 14

-------
A graphical technique for converting the slug-dose data involves
physically measuring the area using a planimeter. The planimeter is an
instrument used to measure the area of a plane closed curve by tracing its
boundary. Calibration of this instrument to the scale of the graph is
required to obtain meaningful readings.
The -ectangle rule is a simple numerical intergration method which
approximates the total area under the curve as the sum of the areas of
individual rectangles. These rectangles have heights and widths equal to
the residual concentration and sampling interval (time) for each data
point on the curve, respectively. Once the data has been converted, T
may be determined in the same manner as data from step-dose tracer tests.
Slug—dose concentration profiles can have many shapes, depending on
the hydraulics of the basin. Therefore, slug-dose data points should not
be discredited by drawing a smooth curve through the data prior to its
conversion to step-dose data. The steps and specific details involved
with evaluating data from both tracer study methods are illustrated in the
following examples.
Examole for Determining TLO in a Clearwell
Two tracer studies employing the step—dose and slug-dose methods of
tracer addition were conducted for a clearwell with a theoretical
detention time, T, of 30 minutes at an average flow of 2.5 MCD. Because
fluoride is added at the inlet to the clearweU as a water treatment
chemical, necessary feed equipment was in place for dosing a constant
concentration of fluoride throughout the step-dose tracer test. Based on
this convenience, fluoride was chosen as the tracer chemical for the
step-dose method test. Fluoride was also selected as the tracer chemical
for the slug—dose method test. Prior to the start of testing, a fluoride
baseline concentration of 0.2 mg/L was established for the water exiting
the clearwell.
Steo-dose Method Test
For the step-dose test a constant fluoride dosage of 2.0 mg / L was
added to the clearwell inlet. Fluoride levels in the clearwell effluent
were monitored and recorded every 3 minutes. The raw tracer study data,
along with the results of further analyses are shown In Table C-i.
c-i 5

-------
TABLE C-I
c. ARWELL DATA--STEP-DOSE TRACER TE5I
Fluonde Concentration
t. innutes Measure& 1L Tracer. mgIL Duiiens onle s, C/Co
0 0.20 0 0
3 0.20 0 0
6 0.20 0 0
9 0.20 0 0
12 0.29 o.ag 0.045
15 0.67 0.47 0.24
18 0.94 0.74 0.37
21 1.04 0.84 0.42
24 1.44 1.24 0.62
27 1.55 1.35 0.68
30 1.52 1.32 0.66
33 1.73 1.53 0.76
36 1.93 1.73 0.86
39 1.85 1.65 0.82
42 1.92 1.72 0.86
45 2.02 1.82 0.91
48 1.97 1.77 0.88
51 1,84 1.64 0.32
54 2.06 1.86 0.93
57 2.05 1.85 0.92
60 2.10 1.90 0.95
63 2.14 1.94 0.96
Notes
1. Baseline coric. = 0.2 rng/L. fluoride dose 2.0 mg/L
2. Measured conc. = Tracer conc. + Baseline conc.
3. Tracer conc. = Measured conc. - Baseline conc.

-------
The steps in evaluating the raw data shown in the first column of
Table C—i are as follows. First, the baseline fluoride concentration,
0.2 mg/I, is subtracted from the measured concentration to give the
fluonde concentration resulting from the tracer study addition alone.
For example, at elapsed time 39 minutes, the tracer fluoride concentra-
tion, C, is obtained as follows:
C C , 1 , 1 0 —
1.85 mg/I — 0.2 mg/I
1.65 mg/I
This calculation was repeated at each time interval to obtain the data
shown in the third column of Table C-i. As indicated, the fluoride
concentration rises from 0 mg/I at t a Q minutes to the applied fluoride
dosage of 2 mg/I, at t = 63 minutes.
The next step is to develop dimensionless concentrations by dividing
the tracer concentrations in the second column of Table C-i by the applied
fluoride dosage, Co 2 mg/I. For time 39 minutes, C/Co is calculated
as follows:
C/Co (1.65 mgfL)/(2.0 mg/I)
0.82
The resulting dimensionless data, presented in the fourth column of
Table C-I, is the basis for completing the determination of by either
the graphical or numerical method.
In order to determine by the graphical method, a plot of C/Co vs.
time should be generated using the data in Table C—I. A smooth curve
should be drawn through the data as shown on Figure C-I.
is read directly from the graph at a dimensionless concentration
(C/Co) corresponding to the time for which 10 percent of the tracer has
passed at the effluent end of the contact basin ( T ) For step-dose
method tracer studies, this dimensionless concentration is C/Co • 0.10
(levensp iel, 1972).
T should be read directly from Figure C-i at C/Co a 0.1 by first
drawing a horizontal line (C/Ca a 0.1) from the V—axis (t a 0) to its
intersection with the smooth curve drawn through the data. At this point
C- 16

-------
FIGURE C-i
C/Co vs. Time
Graphical Analysis for T 10
0 10 20 30 40 50 60
TIME (MINUTES)
0.9
0.
0.
0.6
0
0
a
0.5
0.4
0
0
0.1

-------
of intersection, the time read from the X-axis is and may be found by
extending a vertical line downward to the X-axis. These steps were
performed as illustrated on Figure C-i, resulting in a value for T of
approximately 13 minutes.
For the numerical method of data analysis, several additional steps
are required to obtain T . from the data in the fourth column of Table C-I.
The forms of data necessary for determining T 10 through a numerical
solutton are log 10 (i-C/Co) and t/T, the elapsed time divided by the
theoretical residence time. These are obtained by performing the required
mathematical operations on the data in the fourth column of Table C-i.
For example, recalling that the theoretical detention time, 1, is 30
minutes, the values for log 10 (1-C/Co) and t/T are computed as follows for
the data at t a 39 minutes:
1og 10 (I-C/Co) log 10 (1-0.82)
= log (0.18)
a - Oj%7
t/T a 39 min./30 mm. = 1.3
This calculation was repeated at each time interval to obtain the
data shown n Table C-2. These data should be linearly regressed as
log 10 (1-CfCo) versus t/T to obtain the fitted straight-line parameters to
the following equation:
log 0 (i—C/Co) a m(t/T) + b ( 1)
In equation 1, m and b are the slope and intercept, respectively,
for a plot of 1og 10 (i-C/Co) vs. t/T. This equation can be used to
calculate T 10 , assuming that the correlation coefficient for the fitted
data indicates a good statistical fit (0.9 or above).
A linear regression analysis was performed on the data in Table C-2,
resulting In the following straight-line parameters:
slope • m • -0.714
intercept • b • 0.251
correlation coefficient • 0.93
C-i l

-------
Although these numbers were obtained numerically, a plot of
log 0 (1 -C/Co) versus tli is shown for illustrative purposes on Figure C-2
for the data in Table C-2. In this analysis, data for time = 0 through
9 minutes were excluded because fluoride concentrations above the baseline
level were not observed in the cleat-well effluent until t 12 minutes.
Equation I is then rearranged in the following form to facilitate
a solution for
T /T . (log 10 (1 — 0.1) — b)/m (2)
In equation 2, as with graphical method, T is determined at the
time for which C/Co = 0.1. Therefore, in equation 2. C/Co has been
replaced by 0.1 and t (time) by T 10 . To obtain a solution for T , the
values of the slope, intercept, and theoretical detention time are
substituted as follows:
T /30 mm. = (log 0 (1 - 0.1) - 0.251)/(—0.774)
12 minutes
In sumary both the graphical and numerical methods of data
reduction resulted in comparable values for T . With the numerical
method, T 10 was determined as the solution to an equation based on the
straight-line parameters to a linear regression analysis of the tracer
study data instead of an ueyeballu estimate from a data plot.
Slug-dose Method Test
A slug-dose tracer test was also performed on the clearwell at a
flow rate of 2.5 mgd. A theoretical clearwell fluoride concentration of
2.2 mg/L was selected based on the baseline fluoride concentration of 0.2
mg/L. and to maintain the finished water fluoride level below 2 mg/L. The
fluoride dosing volume and concentration were determined from the follow-
ing considerations:
Dosing Volume
— The fluoride injection apparatus consisted of a funnel anda
length of copper tubing. This apparatus provided a constant
- C-18

-------
0
0
0
0.01
S opo. ma-O.774
,terce . b.O.251
FIGURE C-2
1 —C/Co vs. t/T
Numencal Analysis for T1O
0 0.5 1 1.5 2
trr
2.5
CorrsI. on Co.ffic . -0.93

-------
TABLE C-2
DATA FOR NUMERICAL DETERMINATION OF_110
LLI iQ 0 (l-CfCoi,
0• 0
0.1 0
0.2 0
0.3 0
0.4 -0.020
0.5 -0.116
0.6 -0.201
0.7 -0.237
0.8 -0.420
0.9 -0.488
1.0 -0.468
1.1 -0.629
1.2 -0.870
1.3 -0.75?
1.4 -0.854
1.5 —1.046
1.6 -0.939
1.7 -0.745
1.8 -1.155
1.9 -1.125
2.0 -1.301
2.1 —1.532

-------
volumetric feeding rate of 7.5 liters per minute (L/min) under
gravity flow conditions.
— At a flow rate of 2.5 mgd , the clearwell has a theoretical
detention time of 30 minutes. Since the duration of tracer
injection should be less than 2 percent of the clearweflts
theoretical detention time for an instantaneous dose, the
maximum duration of fluoride injection was:
Max. dosing time 30 minutes x .02 0.6 minutes
- At a dosing rate of 7.5 1/mm, the maximum fluoride dosing
volume is calculated to be:
Max. dosing volume 7.5 1/mm. x 0.6 minutes = 4.5 1
For this tracer test, a dosing volume of 4 liters was
selected, providing an instantaneous fluoride dose in 1.8
percent of the theoretical detention time.
Fluoride Concentration
- The theoretical detention time of the clearwell, 30 minutes,
was calculated by dividing the clearwell volume, 52,100
gallons or 197,200 liters, by the average flow rate through
the clearwell, 2.5 mgd.
- The mass of fluoride required to achieve a theoretical
concentration of 2.2 mg/L is calculated as follows:
Fluoride mass (initial) = 2.2 mg/I x 197,200 1 x J .g 434g
1000 mg
— The concentration of the instantaneous fluoride dose is
determined by dividing this mass by the dosing volume, 4
liters:
Fluoride concentration • 434 g • 109 g/L
41
fluoride levels in the exit to the clearwell were monitored and
recorded every 3 minutes. The raw slug-dose tracer test data are shown
in Table C—3.
The first step in evaluating the data for different times is to
subtract the baseline fluoride concentration, 0.2 mg/I, from the measured
concentration at each sampling interval (Table C-3). This is the same as
the first step used to evaluate step-dose method data and gives the
c-1g

-------
TABLE C-3
CLEARWELL DATA -- SLUG-DOSE TRACER TEST ’’ 2 3
fluoride Concentration
t. minutes Measured. mg/I Tracer. mg/I Dimensionless, C/Co
0 0.2 0 0
3 0.2 0 0
6 0.2 0 0
9 0.2 0 0
12 1.2 1 0.45
15 3.6 3.4 1.55
18 3.8 3.6 1.64
21 2.0 1.8 0.82
24 2.1 1.9 0.86
27 1.4 1.2 0.55
30 1.3 1.1 0.50
33 1.5 1.3 0.59
36 1.0 0.8 0.36
39 0.6 0.4 0.18
42 1.0 0.8 0.36
45 0.6 0.4 0.18
48 08 0.6 0.27
51 0.6 0.4 0.18
54 0.4 0.2 0.09
57 0.5 0.3 0.14
60 0.6 0.4 0.18
63 0.4 0.2 0.09
Notes :
1. Measured conc. Tracer conc. + Baseline conc.
2. BaselIne conc. 0.2 mg/I, fluoride dose = 09 g/L, theoretical conc. 2.2 mg/I
3. Tracer conc. Measured conc. - Baseline conc.

-------
fluoride concentrations resulting from the tracer addition alone, shown
in the third column of Table C-3. As indicated, the fluoride concentra-
tion rises from 0 mg/I at t 0 nnnutes to the peak concentration of 3.6
mgfL at t 18 minutes. The exiting fluoride concentration gradually
recedes to near zero at t = 63 minutes.
The dimensionless concentrations in the fourth column of Table C-3
were obtained by dividing the tracer concentrations in the third column
by the clearwells theoretical concentration, Co = 2.2 mg/I. These
dimensionless concentrations were then plotted as a function of time, as
is shown by the slug-dose data on Figure C-3. These data points were
connected by straight lines, resulting in a somewhat jagged curve.
The next step in evaluating slug-dose data is to determine the total
area under the slug-dose data curve on Figure C-3. Two methods exist for
finding this area —— graphical and numerical. The graphical method is
based on a physical measurement of the area using a planimeter. This
involves calibration of the instrument to define the units conversion and
tracing the outline of the curve to determine the area. The re’ ults of
performing this procedure may vary depending on instrument accuracy and
measurement technique. Therefore, only an illustration of the numerical
technique for finding the area under the slug-dose curve will be presented
for this example.
The area obtained by either the graphical or numerical method would
be similar. Furthermore, once the area is found, the remaining steps
involved with converting the data to the step-dose response are the same.
Table C-4 suninarizes the results of determining the total area using
a numerical integration technique called the rectangle rule. The first
and second columns in Table C-4 are the sampling time and fluoride
concentration resulting from tracer addition alone, respectively. The
steps In app y1ng these data are as follows. First, the sampling time
interval, 3 ilnutes, is multiplied by the fluoride concentration at the
g of the 3-minute interval to give the incremental area, in units of
milligram minutes per liter. For example, at elapsed time, t • 39
minutes, the incremental area is obtained as follows:
C-20

-------
FiGURE C.3
C/Co vs. Time
Conversion ol Slug- to Step-dose Data
1.8
I
1
1.2
0
0
0.8
0.6
0.4
0.2
30 40
TIME (MINUTES)

-------
Incremental area sampling time interval x fluoride conc.
(39-36) minutes x 0.4 mg/L
= 1.2 rng-min/L
This calculation was repeated at each ttme interval to obtain the data
shown in the third column of Table C.4.
If the data had been obtained at unequal sampling intervals, then
the incremental area for each interval would be obtained by multiplying
the fluoride concentration at the of each interval by the time
duration of the interval. This convention also requires that the
incremental area be zero at the first sampling point, regardless of the
fluoride concentration at that time.
As is shown in Table C-4, all incremental areas were summed to
obtain 59.4 mgmin/L , the total area under the slug-dose tracer test
curve. This number represents the total mass of fluoride that was
detected dur ng the course of the tracer test divided by the average flow
rate through the cIearwefl.
To complete the conversion of slug-dose data to its equivalent
step-dose response requires two additional steps. The first involves
summing, consecutively, the incremental areas in the third column of Table
C-4 to obtain the cumulative area at the of each sampling interval.
For example, the cumulative area at time, t 27 minutes is found as
follows:
Cumulative area • 0 + 0 + 0 + 0 + 3 i. 10.2 + 10.8 + 5.4 + 57 + 3.6
38.7 mg-mm/I
The cumulative areas for each interval are recorded in the fourth column
of Table C—4.
The final step in converting slug-dose data involves dividing the
cumulative area at each Interval by the total area under the slug-dose
data curve. For time 39 mInutes, the resulting step-dose data point is
calculated as follows:
C-21

-------
TABLE C-4
EVALUATION OF SLUG-DOSE DATA
Equivalent
Incremental Cumulative Step-Dose
t. minutes fluoride. m /L Ared,. ntg-minIL Area. mg-mm/I Data
0 0 0 0 0
3 0 0 0 0
6 0 0 0 0
9 0 0 0 0
12 1 3 3 0.05
15 3.4 10.2 13.2 0.22
18 3.6 10.8 24.0 0.40
21 1.8 5.4 29.4 0.49
24 1.9 5.7 35.1 0.59
27 1.2 3.6 38.7 0.65
30 1.1 3.3 42.0 031
33 1.3 3.9 0.77
36 0.8 2.4 48.3 0.81
39 0.4 1.2 49.5 0.83
42 0.8 2.4 51.9 0.87
45 0.4 1.2 53.1 0.89
48 0.6 1.8 54.9 0.92
51 0.4 1.2 56.1 0.94
54 0.2 0.6. 56.7 0.95
57 0.3 0.9 57.6 0.97
60 0.4 1.2 58.8 0.99
63 0.2 + 0.6 59.4 1.00
Total Area = 59.4

-------
C/Co 49.5 mg-min/L / 59.4 mg-min/L
0.83
The result of performing this operation at each sampling interval is the
equivalent step-dose data. These data points are shown in the fifth
column of Table C-4 and are also plotted on Figure C-3 to facilitate a
graphical determination of T 10 . A smooth curve was fitted to the step-dose
data as shown on the figure.
can be determined by the methods illustrated previously in this
example for evaluating step-dose tracer test data. The graphical method
illustrated on Figure C-3 results in a reading of T 15 minutes.
C.1.7.3 Additional Considerations
In addition to determining T 13 for use in CT calculations, slug—dose
tracer tests provide a more general measure of the basin’s hydraulics in
terms of the fraction of tracer recovery. This number is representative
of short-circuiting and dead space in the unit resulting from poor
baffling co’iditions and density currents induced by the tracer chemical.
A low tracer recovery is generally indicative of inadequate hydraulics.
However, inadequate sampling in which peaks in tracer passage are not
measured will result in an under estimate of tracer recovery. The tracer
recovery is calculated by dividing the mass of fluoride detected by the
mass of fluoride dosed.
The dosed fluoride mass was calculated previously and was 434 grams.
The mass of detected fluoride can be calculated by multiplying the total
area under the slug-dose curve by the average flow, in appropriate units,
at the time of the test. The average flow in the clearwell during the
test was 2.5 mgd or 6,570 1/mm. Therefore, the mass of fluoride tracer
that was detected Is calculated as follows:
Detected fluoride mass a total area x average flow
59.4 mg-mm x 1 g x 6,570 J.,..
1 1000 mg m m
a 390 g
C-22

-------
Tracer recovery is than calculated as follows:
Fluoride recovery • detected mass/dosed mass x 100
390 g / 434 g x 100
5 90 %
Thu is a typical tracer recovery percentage for a slug-dose test, based
on the experiences of Hudson (1975) and Thirumurthi (1969).
C.1.8 Flow OeDendencv of
For systems conducting tracer studies at four or more flows, the
detention time should be determined by the above procedures for each of
the desired flaws. The detention times should then be plotted versus
flow. For the example presented in the previous section, tracer studies
were conducted at additional flows of 1.1, 4.2, and 5.6 NGO. The T 10
values at the various flows were:
LLO
1.1 25
2.5 13
4.2 7
5.6 4
data for these tracer studies were plotted as a function of the flow,
Q, as shown on Figure C-4.
If only one tracer test is performed, the flow rate for the tracer
study should be not less than 91 percent of the highest flow rate
experienced for the section. The hydraulic profile to be used for
calculating CT would then be generated by drawing a line through points
obtained by multiplying the T at the tested flow rate by the ratio of the
tracer study flow rate to each of several different flows In the desired
flow range.
For the exa le presented in the previous section, the clearwell
experiences a maximum flow at peak hourly conditions of 6.0 mgd. The
highest tested ‘flow rate was 5.6 mgd, or 93 percent of the maximum flow.
Therefore, the detention time, T . 4 mInutes. deterilned by the tracer -
test at a flow rate of 5.6 mgd may be used to-provide a conservative
estimate of T 0 for all flow rates less than or equal to the maximum flow
C-23

-------
FIGURE C-4
Detention Time vs. Flow
0 1 2 3 4 5
FLOW (MOD)
6 7 8
4-Flow profile
1-Flow profile
35
30
25
20
15
10
5.
LU
a
C
t
1
‘ S
‘ S
‘ S
Maximum
Extrapolation
0

-------
rate, 6.0 mgd. the line drawn through points found by multiplying 110
4 minutes by the ratio of 5.6 mgd to each of several flows less than 5.6
mgd is also shown on Figure C .4 for comparative purposes with the
hydraulic profile obtained from performing four tracer studies at
different flow rates.
C.2 Determination of T 10 Without Conducting a Tracer Stud ’ ,
In some situations, conducting tracer studies for determining the
disinfectant contact time, T , may be impractical or prohibitively
expensive. The limitations may include a lack of funds, manpower or
equipment necessary to conduct the study. For these cases, the Primacy
Agency may allow the use of rule of thumb” fractions representing the
ratio of T 10 to T, and the theoretical detention time, to determtne the
detention time, 110, to be used for calculating CT values. Thls.method for
finding 110 involves multiplying the theoretical detention time by the rule
of thumb fraction, T, 0 /T, that is representative of the particular basin
configuration for which is desired. These fractions provide rough
estimates of the actual and are reconinended to be used only on a
limited basis.
Tracer studies conducted by Marske and Boyle (1973) and Hudson
( 1975) on chlorine contact chambers and flocculators /settling basins,
respectively, were used as a basis in determining representative T /T
values for various basin configurations. Marske and Doyle (1973) performed
tracer studies on 15 distinctly different types of full-scale chlorine
contact chambers to evaluate design characteristics that affect the actual
detention time. Hudson (1975) conducted 16 tracer tests on several
flocculation and settling basims at six water treatment plants to identify
the effect of flocculator baffling and settling basin inlet and outlet
design characteristics on the actual detention time.
C.2.1 Intact of Oesign Characteristics
The significant design characteristics include: length-to-width
ratio, the degree of baffling within the basins, and the effect of inlet
baffling and outlet welt configuration. These physical characteristics of
the contact basins affect their hydraulic efficiencies in terms of dead
C — U

-------
space, plug flow, and mixed flow proportions. The dead space zone of a
basin is basin volume through which no flow occurs. The remaining volume
where flow occurs is comprised of plug flow and mixed flow zones. The
plug flow zone is the portion of the remaining volume in which no mixing
occurs in the direction of flow. The mixed flow zone is characterized by
complete mixing in the flow direction and is the complement to the plug
flow zone. All of these zones were identified in the studies for each
contact basin. Comparisons were then made between the basin configura-
tions and the observed flow conditions and design characteristics.
The ratio rio/I was calculated from the data presented in the studies
and compared to its associated hydraulic flow characteristics. Both
studies resulted in T /T values which ranged from 0.3 to 0.7. The results
of the studies indicate how basin baffling conditions can influence the
T /I ratio, particularly baffling at the inlet and outlet to the basin.
As the basin baffling conditions improved, higher T /T values were
observed, with the outlet conditions generally having a greater impact
than the inlet conditions.
As discovered from the results of the tracer studies performed by
Marske and Boyle (1973) and Hudson (1975), the effectiveness of baffling
in achieving a high T fT fraction is more related to the geometry and
baffling of the basin than the function of the basin. For this reason,
T /T values may be defined for three levels of baffling conditions rather
than for particular types of contact basins. General guidelines were
developed relating the T /T values from these studies to the respective
baffling characteristics. These guidelines can be used to determine the
values for specific basins.
t.2.2 Baffling Classifications
The purpose of baffling is to maximize utilization of basin volume,
increase the plug flow zone In the basin, and minimize short circuiting.
Some form of baffling at the inlet and outlet of the basins Is used to
evenly distribute flow across the basin. Additional baffling may be
provided within the interior of the basin (Intro-basin) in circumstances
requiring a greater degree of flow distribution. Ideal baffling design
C-25

-------
reduces the inlet and outlet flow velocities, distributes the water as
uniformly as practical over the cross section of the basin , minimizes
mixing with the water already in the basin, and prevents entering water
from short circuiting to the basin outlet as the result of wind or density
current effects. Three general classifications of baffling conditions --
poor, average 1 and superior -- were developed to categorize the resu’ts
of the tracer studies for use in determining T from the theoretical
detention time of a specific basin. The 1 10 1T fractions associated with
each degree of baffling are suimnarized in Table C-5. Factors representing
the ratio between T 1 and the theoretical detention time for plug flow in
pipelines and flow in a completely mixed chamber have been included in
Table C-5 for comparative purposes. However 4 in practice the theoretical
T 10 /T values of 1.0 for plug flow and 0.1 for mixed flow are seldom
achieved because of the effect of dead space. Conversely 4 the T 0 /T values
shown for the intermediate baffling conditions already incorporate the
effect of the dead space zone 1 as well as the plug flow zone, because they
were cI riv d empirically rather than from theory.
As indicated in Table C -S, p . baffling conditions consist of an
unbaffled inlet and outlet with no intra-basin baffling. Average baffling
conditions consist of intra-basin baffling and either a baffled inlet or
outlet. Superior baffling conditions consist of at least a baffled inlet
and outlet, and possibly some intra—basin baffling to redistribute the
flow throughout the basin’s cross—section.
The three basic types of basin inlet baffling configurations are:
a target-baffled pipe inlet, an overflow weir entrance, and a baffled
submerged orifice or port inlet. Typical intra-basin baffling structures
include: diffuser (perforated) walls; launders; cross, longitudinal, or
maze baffling to cause horizontal or ert1cal serpentine flow; and
longitudinal divider walls, which prevent mixing by increasing the
length-to-width ratio of the basin(s). Comonly used baffled outlet
structures Include free-discharging weirs, such as sharpcrested and
V—notch, and submerged ports or weirs. Welts that do not span the width
of the contact basin, such as Cipolleti weirs, should not be considered
C-26

-------
TA8LE C-S
BAFFLING CLASSIFICATIONS
Baffling Conditio n 1 i i Bafflinoi Description
unbaffled (mixed flow) None, agitated basin, very low length to
width ratio, high inlet and outlet flow
velocities
Poor 0.3 Single or multiple unbaffled inlets and
out1ets, no intra—basin baffles
Average 0.5 Baffled inlet j outlet with some intra-
basin baffles
Superior 0.7 Perforated inlet baffle 4 serpentine or
perforated intra-basni baffles, outlet weir
or perforated launders
Perfect (plug flow) 1.0 Very high length to width ratio (pipeline
flow), perforated inlet, outlet, and intra-
basin baffles

-------
baffling as their use may 5ubstantlally increase weir overflow rates and
the dead space zone of the basin.
C.2.3 Exarnoles of Baffling
Examples of these levels of baffling conditions for rectangular and
crrcular basins are explained and illustrated in the following section.
Typical uses of various forms of baffled and unbaffled inlet and outlet
structures are also illustrated.
The plan and section of a rectangular basin with baffling con-
ditions, which can be attributed to the unbaffled inlet and outlet pipes,
is illustrated on Figure C-5. The flow pattern shown in the plan view
indicates straight-through flow with dead space occurring in the regions
between the individual pipe inlets and outlets. The section view reveals
additional dead space from a vertical perspective in the upper inlet and
lower outlet corners of the contact basin. Vertical mixing also occurs
as bottom density currents induce a counter-clockwise flow in the upper
water layers.
The inlet flow distribution is markedly improved by the addition of
an inlet diffuser wall and intra-basin baffling as shown on Figure C-6.
However, only average baffling conditions are achieved for the basin as
a whole because of the inadequate outlet structure -— a Cipolleti weir.
The width of the weir is short in comparison with the width of the basin.
Consequently, dead space exists in the corners of the basin, as shown by
the plan view. In addition, the small weir width causes a high weir
overflow rate, which results in short circuiting in the center of the
basin.
Superior baffling conditions are exemplified by the flow pattern and
physical characteristics of the basin shown on Figure C-?. The inlet to
the basin consists of submerged, target-baffled ports. This inlet design
serves to reduce the velocity of the incoming water and distribute it
uniformly throughout the basin’s cross—section. The outlet structure is
a sharpcrested welt which extends for the entire width of the contact
basin. This type of outlet structure will reduce short circuiting and
decrease the dead space fraction of the basin, although the overflow welt
C-27

-------
-- , / / / / ,
/
— — -
—
— .—
- -
— — ____
____ — -
— — .
- - - - -
PLAN
7-
/ ______
/
(
/ _ _
— —
__ __
SECTION
FIGURE C-5 POOR BAFFL 1NG CONDITIONS - -
RECTANGULAR CONTACT BASIN

-------
/
/ —
/
A
FIGURE C-S AVERAGE BAFFLING CONDITIONS - -
RECTANGULAR CONTACT BASIN
/
/
— a
/
I
/ • a
/
71
/
-4
/,
/•
. -
I ’
PLAN
StCTION

-------
FiGURE C .7
SUPERIOR BAFFLING CONDITIONS - -
RECTANGULAR CONTACT BASIN
it
/
/
I A
/
SECTION

-------
/ //// ////
- J
SECTION
FIGURE CS POOR BAFFLING CONDITIONS -
CIRCULAR CONTACT BASIN
Pt. A N
V
I i-
—‘

-------
dr _

/ ///1 / /Z//Z/ZZ// / 7 / 7/7 ,
SECTION
FIGURE C-9 AVERAGE BAFFLING CONDITIONS - -
CIRCULAR CONTACT BASIN
PLAN

-------
FIGURE C.1 0 SUPERIOR BAFFLING CONDITIONS - —
CIRCULAR CONTACT BASIN
PLAN
S!CflON

-------
does create some dead space at the lower corners of the effluent end.
These inlet and outlet structures are by themselves sufficient to attain
superior baffling conditions; however, maze-type intra-basin baffling was
included as an example of how this type of baffling aids in flow
redistribution within a contact basin.
The plan and section of a circular basin with p..g. baffling
conditions, which can be attributed to flow short circuiting from the
center feed well directly to the effluent trough is shown on Figure C-8.
Short circuitinç occurs in spite of the outlet weir configuration because
the center feed inlet is not baffled. The inlet flow distribution is
improved somewhat on Figure C-9 by the addition of an annular ring baffle
at the inlet which causes the inlet flow to be distributed throughout a
greater portion of the basinls available volume. However, the baffling
conditions in this contact basin are only average because the inlet center
feed arrangement does not entirely prevent short circuiting through the
upper levels of the basin.
Superior baffling conditions are attained in the basin configuration
shown on Figure C-1O through the addition of a perforated inlet baffle and
submerged orifice outlet ports. As indicated by the flow pattern, more
of the basin’s volume is utilized due to uniform flow distribution created
by the perforated baffle. Short circuiting is also minimized because only
a small portion of flow passes directly through the perforated baffle wall
from the inlet to the outlet ports.
C.2.4 Additional Considerations
Flocculation basins and ozone contactors represent water treatment
processes with slightly different characteristics from those presented in
Figures C—5 through C-tO because of the additional effects of mechanical
agitation and mixing from ozone addition, respectively. Studies by Hudson
(1975) IndIcated that a single-compartment flocculator had a T 0 /T value
less than 0.3, corresponding to a dead space zone of about 20 percent and
a very high mixed flow zone of greater than 90 percent. In this study,
two four—compartment flocculators, one with and the other without
mechanical agitation, exhibited T 10 1T values in the range of 0.5 to 0.7.
C-28

-------
This observation indicates that not only will compartmentatian result in
higher T fT values through better flow distribution 1 but also that the
effects of agitation intensity on T /T are reduced where sufficient
baffling exists. Therefore, regardless of the extent of ag itation,
baffled flocculation basins with two or more compartments should be
considered to possess average baffling conditions (T 0 /T 0.5), whereas
unbaffled, single-compartment floccuLation basins are characteristic of
poor baffling conditions (T /T 0.3).
Similarly, multiple stage ozone contactors are baffled contact
basins which show characteristics of average baffling conditions. Single
stage ozone contactors should be considered as being poorly baffled.
However, circular, turbine ozone contactors may exhibit flow distribution
characteristics which approach those of completely mixed basins, with a
T 10 /T of 0.1, as a result of the intense mixing.
In many cases, settling basins are directly connected to the
flocculators. Data from Hudson (1975) indicates that poor baffling
conditions at the flocculator/settling basin interface can result in
backniixing from the settling basin to the flocculator. Therefore,
settling basins that have rntegrated flocculators without effective inlet
baffling should be considered as poorly baffled, with a T 0 /T of 0.3,
regardless of the outlet conditions, unless intra-basin baffling is
employed to redistribute flow. If Intra-basin and outlet baffling is
utilized, then the baffling conditions should be considered average with
a T /T of 0.5.
Filters are special treatment units because their design and
function is dependent on flow distribution that Is completely uniform.
Except for a small portion of flow which shortcircults the filter media
by channeling along the walls of the filter, filter media baffling
provides a high percentage of flow uniformity and can be considered
superior baffling conditions for the purpose of determining T 10 . As such,
the T 0 value can be obtained by subtracting the volume of the filter media,
support gravel, and underdrains from the total volume and calculating the
theoretical detention time by dividing this volume by the flow through the
f liter. The theoretical detention time Is then multiplied by a factor of
c-29

-------
0.7, corresponding to superior baffling conditions, to determine the
value.
C.2.5 Conclusioni
The recommended 110/1 values and examples are presented as a
guidehne for use by the Primacy Agency in determining T values in site
specific conditions and when tracer studies cannot be performed because
of practical considerations. Selection of 1 10 /T values in the absence of
tracer studies was restricted to a qualitative assessment based on
currently available data for the relationship between basin baffling
conditions and their associated T /T values. Conditions which are
combinations or variations of the above examples may exist and warrant
the use of intermediate I /1 values such as 0.4 or 0.6. As more data on
tracer studies become available, specifically correlations between other
physical characteristics of basins and the flow distribution efficiency
parameters, further refinements to the T 10 /1 fractions and definitions of
baffling conditions may be appropriate.
References
Hudson, H. E., Jr.. ‘Residence Times in Pretreatment’, J. AWWA, pp. 45-52,
January, 1975.
Hudson, H. E., Jr.. Water Clarification Processes: Practical Design and
Evaluation , Van Nostrand Reinhold Company, New York, 1981.
Levenspiel, 0.. Chemical Reaction Engineering , John Wiley & Sans, New
York, 1972.
I4arske, 0. 14. and Boyle, J. 0.. “Chlorine Contact Chamber Design — A Field
Evaluation TM , Water and Sewage Works, pp. 70—77, January, 1973.
Thlru:urthi, D.. TM A Break-through In the Tracer Studies of Sedimentation
Tanks”, J. WPCF pp. R405-R418, November, 1969.
C-30

-------
PpE )IXC : ‘0NCE ’TRATING, PROCESSING
flETE’ TIT4G AND IDENTIFYflIG GIAPOIA CYSTS TN WATE’
lETHOD INVESTIGATOR (5) RESULTS
1. e’i r ne Filtration
Cellu sic ‘hang and Kabler Generally unsuccessful
P7r m -O. 4 5un) USPHS, 19 6
øolycarHnate Pyper, DuFrain and Henry Eng Passing 1 gal/mm at
19R , (unpublished) 10 PSI. 15-180 (1 gal
total
2. PartIculate Filtration Shaw et al, 1977 Ge’ierally gooc’ ren v l
[ thatomacecus earth, sanil, JurariiE,T979 but poor eluation
etc. )
3. Algae (Foerst) (en’ rifuqe Holman et al, 1983 Good rapid recovery,
DHHS, W ihTh gton hut limited In field
use
4. Anionic and Cationic Brewer, Wright State UN. Generally unsuccessful
Exchanqe Resins (unpublished)
Epoxv-Fiherglass Ralston Riggs, CDHS Lab, Berkley, CA Over3ll recovery 2 -8O
Tube Filters (unpublIshed) percent
‘. Mi’roDorous Yarnwnven i eo t h . J k’ibowski, ErIckson, 1979 and Recovery 3-15 percent
F 1 ters 1980, EPA-Cincinnati Extraction ave. 58
(1 nd lum orion an percent
polvproivlen )
7. Pel’ican Cassette System Millinore Carp, May be useful for
(unpublishetil processing filter
washings
8. F lterwashfng pparatus Duwalle, U. of Wash., 1982 Claims 75 percent
(unpublished) recovery fror orion
filters
TABLE 1
(Cl

-------
APPENDIX C: CO ICEWTRATI IV, DR’XF SSL’iS.
DETECTIUG AND IDE JTIFYING GIARDIA CYSTS IN ‘4ATER
PRIMARY C0 YENTR TIDH ANfl PPOCESSItJG METH )flS
1. MEMBRANE FILTER (MF) i TH0DS
r l, l ir (nrixerl esters of cellulose )
1. Chan’i and Kabler n 1955
First to use MF for cyst recovery. Recovere 2C-42 percent at cyst
concentration of 3, , an 10 cyst/aal. - nn c 5t founi at
1 cyst/gal.
2. 1e ho 1 was used in 1965 Colorado outhr ak (Moore, et al, 1969) using
P liter size water samples from 10 sites. No cystiThi e detected.
Use ‘ celliziosic filters have generally not 5een successful in
derncrnstrating cysts in drinking water.
b. Pnlycarbnna1 e (PC) Filtørs
1. Luchtel and Colleaqes in 198fl used 293 rn, 5.0 ufl pore size
nucleocore (PC) filters to concentrata fon’ alin-fixe 1. G. lamblia
cysts frun 20 . tap water samples. Recovery rates of ap5ro imateTy
7c perc ’nt were reoorterl.
2. Pyper of i)uFraln nd Henry Engineers claim good recovery with same
nucleopore filter at f 1 ow rate of 1 gal .1mm., not over 10 P3!,
passing 15-1800 gal. in just over 24 hours.
c. Even with thcse claims by Pyper and Luchtel, the flE lethod has only once
(Aspen, l9 ) heen successful in demonstrating cysts in water--Drobably
because:
1. Ina’,ility to process a sufficient volume.
2. Ina’ility to re iove cysts from *llter.
3. Cysts weren’t present at time of sampling during or after outbreak.
2. pApTIrl,LATr FTt’ RATI(flJ
a. SAU ) - CDC (Shaw, 1977) used high-vol filtratIon thrc g1i swltmning cool
san ” filter (280,000 qal. total over 10 days) - was ackflushed into 55
gal. iru’ns ane’ coagulated w/alun. Concentration fed to beagle puppies
an ’ 1 after treatment (cheesecloth to wire screeninç to 33 n MF to
centrifuge) was examlne’t microscopically. First time cysts observed in
water suo ly after concentration.
b. ‘ )latomaceous earth (flE’ ) - COC (Juranek, l979) used DE to remove cysts
frr seed ’ 1 wator. Prni,lem was t’iat cysts co l’ n’t be removed fro’, DE
particles. Brewer (1983) claIms 5.2-31.1 pe cent recovery from DE
backwash. Retention thro’ gh 3 forms (celit SOS, HyFlo-Supercel and
celite 5 O) at cyst concentration ranging ‘tom 6-16,000 cyst/L. Recovery
range betwe n 66-100 percent.
C2)

-------
APP JDIX : C UCENTR TIWG, PROCESSflif ,
DETECTPJG ANfl IDEUTIFYING GIARnIA CYSTS IN WATER
P GAE CENTRIFUGE
a. Was found to recover more cysts (lOX) than a series of MV-filters and
nylon screens: 5 vs. 1 day hy MV.
b. May he irrnracticai in field because of power requirement.
c. If used in lab, I large single sample collected in the field could miss
cyst.
,l May find application concentration cysts from orion filter washings.
4. A JTO JIC APfl) CATV)UTC EXCHANGE RESINS (Brewer - unpublish eJ)
a. Based on hypothesis that Cysts could be attracted to charged surfaces,
cysts have a charg of approximately 2SrnV at pH 5.5 which increases In
electro-negativity as the pH rIses to 8.0.
b. Charge attraction techniques have beefl used for concentration of both
bacteria and viruses in water.
c. Five exchange resins were tested:
(1. percent recovery from anfonic Dowex 1-XY columns
(2. 38 percent recovery from cationic Dowex 50W-X8 columns
ii Compared to parallel tests wfdiatomaceous earth, exchange resins less
e’ficient in retention .
5. RALc OtI tPO V-FIBERGLASS TUBE FILTERS
a. Riggs of CStID, Viral and Rick. Lab., can fIlter 500 gallons drinking
water thru lost — 8 rn Baiston tube tilter.
h. Backfl’jshes wIl L 3 percent beef extract or solution of 0.5 percent
potassiu’l citrate.
c. Concentration is centrifuged w/40 percent potassium citrate and middle
layer ffltered thru 5 u polycarbonate filters.
d. Uses v rect $!‘runofluorescence antibody technique for detection and
i nt1 1cation.
e. Claims 0-BD percent efficiency In collection, preprocessing and ID.
& MICROPORIUS YA’W 0YEN flEPTH FTLTE!1S
a. In 197 EPA develooel a concentration-extraction method Involving large
volumes of water thru microporous yarnwoven orion-fiber filters.
b. This t’ ethort has been tenatively adopted as the “method of choice’ f or
concentrsting cysts from water suoplies.
(C3

-------
ApD Wt EX C: f0 CEHTRATINc , PROCESStMG,
ETEc r G A ID fl HTJFyI IG GIAROI& CYSTS IN WATER
c. Since Initial studies which sh w d only 3-15 percent recovery with a mean
of 6.3 percent an ’ 4 a 58 percent extraction rate, several changes have 5een
n aie which my have increase i the retention rate to >20 percent.
1. Gone from 7 to 1 n pmrsity filter
2. Limited the rae of f1o to 1/2 gallon/mm
3. L t mited the pressure head to 10 PSI
4. Have gone to po’yproyl ne filters in lieu of orion
d. It was the first methol successfully used to detect cysts in the
distribution syste l of a community water supply.
e. Is the recommended fflter to he used hy the EPA consensus method.
7. P LLlCAN CASSET’ E SYST!i1
a. Is a p ete and frame style holier which accepts both u tra thin and • epth
t”pe filters.
h. Has from 0.5 to 25 ft 2 of filter area.
c. Has not been investigate 4 thoroughly but has had some success in virus
concerttrati on.
d. Tts math application for cyst recovery may lay with the processing of
filter washlnqs.
9. FILTERW SHP G APPARATUS
a. This is a proposed device by DuWaile, 1982 from U. of W., for unwinding
the fibers from the filter cartridge while repeatedly brushing au’d
sgueezing them while In a bath solution.
b. Bath could cont 1n either a surfactant or pH controlled so)uti’n.
c. Potential claims are as high as 75’percent extraction of cysts from the
fibers.
TABLE 2: OrrECTION IIETHODS
METHOI) INVESTIGATOR(S) RESULTS
1. lrimuno’luorescence Riggs, CS f5 Lab, Berkley, CA Good prep.,
a. flFA 1983 Cross Rx
b. ICA Sauch, cPA-Cincinnati Still under study
Riggs, CSDS
c. Monoclonal Antlbo4lles Rtg s, CSDHS Still under study
Sauch, EPA—CIncinnati
(unpublished)
2. ELISA Method Hunger, J. Hopkins MD, 1983 Feces samples only
4)
3. Rrightffeld/Phase Cont—ast EPA Consensus method Ongoing

-------
4PPEMI)!X C: O !C NTRATT 1G PQOCESSTNG,
flET TING AND IDENTIFYING 1M DIA CYSTS IN WA’ER
flETECTI()M MET 1ODS
l.a. flIRECT L1JORE5CEPJT A! TIBODY (DR ) TECHNIQUE
1. Riggs has oroduce’l a high titer purified imune sera to Giardia lamblia
cysts in guinea pigs and laheled it with fluorecein isothio cyanate. Sera
Is purified thru NH 4 OH an 4 )EAE se adex fractionation.
2. Obtained cross reactions with Chflonastix nesn1li cysts hut claims it can
be easily distinguished from Giardia by its smaller size.
l.b. TUflIREC FLUORESCENT A rT8ODY (IFA) TECHNIQUE
1. Sauch using IFA with imune sera from rabbits (unourifled). It is reacted
with cor nerci ally available fluorescent-labeled coat anti -rabbit gamma
globulin.
2. Some cross-reactions with certain algal cells.
1.c. Mr) ,OCLOP!AL APJTIRO!)IES
1. Using cleines of hybridorna cell lines obtained by fusing mouse myeloma
cells with s’ 1 en cells from mIce (BALB/c) inriunized with C. larnblia
troohozol tes.
2. Produ’ed eiqht ,nonoclnnal antibodies evaluated by IFA against both trophs
ane( cysts.
a. 3/8 stained the ventral disk
b. 2 staine 1 the nuclr l
c. 2 stained cytoplasmic granules
d. 2 stainel membrane co. nnon nts
3. VariabIlity in sta 4 ning may be due tg’ differences in stages of encystment.
4. Preliminary results in.1i ate nonoclonal ABs may give rapid and specific ID
n’ cysts.
5. Rx may be too specific, not reacting with all human fonns of C. lamblf a
may have to go to polyclonal Ms.
2. ELISA ‘ TW I )
a. Hungar at John Hopkins (unpubllshe’i) has produce i a .Ietection method by
ELISA usini a Intact sanr$wich tec rnique In 96-well inicrotiter plates.
b. Using antisera from 2 different animals (may present problem).
c. PJe 4 a minimum of 12 cysts/well for color Rx.
(CS

-------
APPENDIX 0
ANALYTICAL REQUIREMENTS OF THE SWTR AND
A SURVEY OF THE CURRENT STATUS OF RESIDUAL DISINFECTANT
MEASUREMENT METHODS FOR ALL CifLORINE SPECIES AND OZONE

-------
APPENDIX D
ANALYTICAL REQUIREMENTS
Cnly the analytical method(s) specified in the SWZR, or otherwise ap-
proved by EPA, may be used to demonstrate compliance with the requirements of
the SWrR. Measurements of pH, temperature, turbidity, and residual disinfec-
tant concentrations must be conducted by a party approved by the Primacy
Agency. Measurements for total coliforms, feca]. coliforms, and heterotrophic
bacteria as measured by the heterotrophic plate count (HPC), must be conducted
by a laboratory certified by the Pri.mac’y Agency or EPA to do such analysis.
tintj.L laboratory certification criteria are developed for the analysis of HPC
and feca]. coliforns, any laboratory certified for total coliform analysts is
acceptable for fWC and fecal coliform analysis. The test methods to be used
for various analyses are listed below:
(1) Fecal coliform concentration — Method 906C (MPN Procedure), 9080
(Estimation of Bacterial Density), or 909C (Membrane Filter Proce-
dure) as set forth in Standard Methods for the Examination of Water
and Wastewater , American Public Health Association, 16th edition.
(2) Total coliform concentration - Methods 908k, B, 0 (MPN Procedure) or
909k, B (Membrane Filter Procedure) as set forth in Standard Methods
for the Examination of Water and Wastewater , American Public Health
Association, 16th edition; Autoanalysis Coli].ert (EPA refers to this
as Minimal Medium ONPG-MUG Method), as set forth in Applied and
Environmental Microbiology, American Society for Microbiology,
Volume 54, No. 6, 3une 1988. pp. 1595—1601.
(3) Heterotorphic Plate Count — Method 907k (Pour Plate Method) as set
forth in Standard Methods for the Examination of Water and Waste—
water , American Public Health Association, 16th edition.
(4) Turbidity — Method 214k (Nephelometric Method) as set forth in
Standard Methods for the Examination of Water and Wastewater ,
Ameri.ca.n Public Health Association, 16th edItion.
(5) Residual disinfectant concentration — Residual disinfectant concen-
trations for free chlorine and combined chlorine must be measured by
Method 408C (Amperometric Titration Method), Method 4080 (DPD
Ferrous Titrimetric Method), Method 408E (DPD Colorinetric Method),
or Method 400? (Leuco Crystal Violet Method) as Bet forth in Stan-
dard Methods for the Examination of Water and Vastewater , American
Public Health Association, 16th edition. Disinfectant residuals for
free chlorine and combined chlorine way also be measured by using
DPD colorimetric test kits if approved by the Primacy Agency.
D-1

-------
Disinfectant residuals for ozone must be measured by the Indigo Tn—
sulfortate Method (Bader, It., Koigne, .7.., “Determination of Ozone in
Water by the Indigo Method; A Submitted Standard Method;” Ozone
Science and Engineering, Vol. 4, pp. 169—176, Pergamon Press Ltd.,
1982), or automated methods which are calibrated in reference to the
results obtained by the Indigo Trisulfonate Method, on a regular
basis, as determined by the Primacy Agency. This method is de-
scribed in section of the manual. (Note: This method is included in
the 17th edition of Standard Methods for the Examination of Water
and Wastewater , American Public Health Association; the Idiodometnc
Method in the 16th edition may not be used.) Disinfectant residuals
for chlorine dioxide must be measured by Method 4102 (Amperometric
Method ) or Method 410C (DPD Method) as set forth in Standard Methods
for the Examination of Water and Wastewater , American Public Health
Association, 16th edition.
(6) Temperature — Method 212 as set forth in Standard Methods for the
Examination of Water and Wastewater , American Public Health Asso-
ciation, 16th edition.
(7) pM — Method 423 as set forth in Standard Methods for the Examination
of Water and Wastewater , American Public Health Association, 16th
edition.
References
Edberg et al, “National Field Evaluation of a Defined Substrate Method for the
Simultaneous Enumeration of Total Coliforms and Escherichia Coli from Drinking
Water: Comparison with the Standard Multiple Tube Fermentation Method,’
Applied and Environmental Microbiology, Volume 54, pp. 1595-1601, June 1988.
D-2

-------
PREFACE
The AWWA paper entitled “A survey of the current status of residual
disinfectant measurement method for all chlorine species and ozone” will be
included in the final document. It he,s’ r r included here £ot aS2 f
However, the publication is available from the AWWA Customer Ser-
vices Department, 6666 W. Quincy Avenue, Denver, Co. 80235; Telephone (303)
794-7711. The document publication number is 90529.
The above publication suniarizes the AWWA Research foundation’s 816 page
publication entitled “ Disinfectant Residual Measurement Methods”, publication
number 90528. This document is also available from the customer services
department listed above.
D-3

-------
A SURVEY OF THE CURRENT STATUS OF RESIDUAL DISiNFECTAHT
MEASUREMENT METHODS FOR ALL CHLORINE SPECIES AND OZOHE
by
Gilbert Gordon
Departaient of Ciemistry
Miami University
Oxford, OH 45056
William J. Coooer
Drinking Water Research Center
Florida !nternational 1Jn versity
Miam i Florida 3199
Rip G. Rica
Rice, Incorporated
Ashton, Maryland 20861
Gilbert E. Pacey
Department of Chemistry
Miami University
Oxford 1 Ohio 45056
Prepared for:
AW t AA Resatrch Foundation
5666 W. Quincy Avenue
Denver, C D 80235
November 1987
Published by the American Water Works Association

-------
DISCUIMER
This sz dy was funced by the Mier,can Water Works As3ac aticn
Researc Founcation (AWWA F). AWWARF assumes no resOonS7bil—
ity for the content of the research s; dy reocrtao in this
publication, or for the coin ons or statenents of 4 ac:
expressed in the re or. The mention of tradenaxnes for
c m ercia1 products does not represent or imply the approval
or endors iient of AW’.iIARF. This report is presenteo sole’y
for informational purposes.
Although the research describe’ in this document has been
funded in part by the Unitad States Environmental Protection
Agency tflrougn a Coocerative Agre nent, C —811335—O1, to
AWWARF, it has nct bee’i subjec;ed to Agency revieA arid
therefore does not necessarily reflect the views of the
Agency and no official endors nent snou1d be inferrec.
Copyright I 87
by
nerfc n arar Works Association Research Foundat,On
Prfnte in U.S.
‘11

-------
FOREtJCRD
This report Is pert of the ott-go ing researth pro ran of the AWWA Researcn
Pounoation. The researcn described in the following pages was funced by
the Foundation in benalf of its mernoers and subscribers in particular and
the water suopty industry in general. Selected for funoing by AWWARF’s
Board of Trustees, the project was Identified as a prac:;cal, priority need
of the incus:rv. t Is hoped that this puolication will receive wide arid
serious attention and that its ftndings, concFusions, and reconrendations
will be applied In commurntles throughout the United States arm Canada.
The Research Foundation was created by the water suoply industry as its
center for cooperative research and development. The Foundation itself
does not conduct research; it functions as a planning and managanent
agency) awarcing contracts to other institutions, such as water utilities,
universities, engineering fims, and other organizations. The scientific
and technical expert ise of the staff Is further ennanced by inoustry
volunteers who serve on Project Advisory Cousnittees and on other standing
cosrmnttees and councils. -An ext2nsive planning process .nvolves many
hundreds of water professIonals in the important task Of keeping the
Foundation ’s program responsive to the practical, operational needs of
local utilities and to the general research an develotment neecs of a
progressive industry.
All aspects of water supply are served by AWWARF’s research agenca:
resource!) treattent ano operacicns, discrioution and storage, water
quality and analys;s, economics and management. The ultimate purpose of
this effort is to assist local water suopliers to provide the hignest
pcss;ble quality of witer, economically and reliably. The Foundation’s
Trustees are please’i to offer this publication as c;ntrtbution toward that
end.
This project reviewed all disinfectant residual measurement methods for
free cilorine , cflloraznines, ozone and chlorine dioxide with special
attention to Intertereices cnac could be experienced by tie water utility
Industry. Recnznendations) practical cuidance, and c3ut ons on the
selection of acoropriate residual measurement techniques are summarized
(Please see Preface for Infonoation on full report).
s 0 r -
c 1 9es F. lanwaring, ?. .
aeciztive 01 rector
tWWA Research Foundation
2eseartn Foundation
l i i

-------
PREF .C
This ocument anzes t e AWWA Research Foundat ori’s 815 pace
puolic3t lon ‘ 1 Disinfectant Residual easurenienc Methoos.” That
puc1icat cn (Publication Nuinoer 90528) can be ordered frcm t ie AW’14A
Customer Services Cepart ent, 66 6S W. Quincy Avenue, Denver, C3 80235;
telepnone, (303) 794—7711.
The purpose of this summary document is to provide t e water utility
laboratory analyst with guidance in selecting disinfectant residual
measurement methods. Either this document or the full reoort is
reccn temded as a comoanion to Stanoard Methods or the Examination of
Water and Wastewater.

-------
AcX OWl .EDGZMENTS
The authors wisn to exoress their appreciation to the American Water Works
Association — Resear:h Foundation for the opportunity to carry out this
detailed review of the literature.
Furthermore, the authors would like to pay tribut to the really important
people —— all.those wno did the original work and made this secondary
source of Information possible.
Finally, the authors wish to express their appreciation to the memoers of
the Project Advisory Co ittee:
1) Mark Carter, Ph.D.
Rocky Mountain Analytical Laboratories
2) J. Donald Jonrison, Ph.D.
University of lorth Carolina
3) Leown A. Moore
Drinking Water Research Division— —EPA
4) R. Rhodes Trjss ll, Ph.D.
James M. Mont;cmery Consul irig Engtheers, mc.
G. G.
W .J.. C.
R.t3.R
G.E.P.
•1

-------
WCVtzvg SUMMARY
BACKGROUND
The objective of this Report is to review and summarize all disinfectant re-
sidual measurement techniques currently available for free chlorine (along with
the various chloramines), combined chlorine 1 chlorite ion, chlorine dioxide,
chlorate ion, and ozone.
Presently, both chlorine dioxide and ozone are gaining considerable favor as
alternatives to chlorine disinfection (1). The analytical chemistry for these
disinfectants when compared with chlorine is even more complex and less readily
understood as evidenced by various surveys (2-5) and detailed research carried
out in various laboratories (6-10).
Chlorine dioxide is manufactured at the site of its use by reactions involv-
ing sodium chlorite, chlorate ion, chlorine gas and/or hypochlorite ion and sul-
furic acid or hydrochloric acid (11-12). Consequently, chlorate ion, chlorite
ion, hpochlorite ion and/or hypoch lorous acid frequently will be found occur-
ring as by-products or unreacted starting materials. These materials are strong
oxidizing agents which are very reactive and behave in many ways similar to
chlorine dioxide itself.
There are more than 2,000 water treatment plants today using ozone, and less
than half of them are applying ozone solely for disinfection. The large major-
ity of water treatment plants use ozone as a chemical oxidant. Many of the
plants applying ozone for disinfection also are using ozone, in the same plant,
for chemical oxidation. Analyses for resid u al. ozone in water arc applicable
only in the treatment plant, either in the ozone contactor(s) or at their
outlets. Residual ozone is never present in the distribution system; however.
its by-products may be.
There have been numerous attempts to evaluate the relative advantages and
disadvantages associated with the measurement of free end combined chlorine.
Different criteria are frequently used for the evaluation of the analytical
measurements and often suggestions for the improvement of test procedures have
gone largely ignored. No comprehensive and objective review of the literan.zre
appears to be available. This Report is aimed at providing such a review along
with guidance and recommendations as to what criteria water utilities should use
in selecting residual monitoring techniques based on circumstances by category.
OJJEcrivtS
1. to review and summarize all residual measurement techniques
currently available for fret chlorine- - taking into account
the roles of chloramines.
2. to review and summarize all residual measurement techniques
currently available for combined chlorine.
1

-------
3. To briefly review the present understanding of the chlorine-
ammonia chemistry and in particular, in relationship to the
measurement of chlorine and combined chlorine.
4. To review and summarize all residual measurement techniques
currently available for chlorine dioxide, chlorite ion and
chlorate ion.
5. To review and summarize the analytical procedures currently
used by operating water utilities to control ozone treatment
processes, considering disinfection as well as the many oxid•
acive applications of ozone in water treatment applications.
6. To discuss coon interferences associated with the measurement
of each of the disinfectancs/oxidants described above (free
chlorine, combined chlorine, chlorite ion, chlorine diox .de,
chlorate ion, and ozone).
7. To provide guidance and recommendation for water utilities in
selecting residual monitoring techniques for each of the above
disinfeccaxits/oxidants.
8. To recommend future research for development of monitoring and
analytical methods to improve accuracy, and reduce time and. cost
requirements for the measurement of the above disinfactants.
In the full report, we present as coaplete as possible an examination of the
world-wide body of literature on analytical methods used by the water ut liry
industry in order to elaborate on the various problems, advantages, disadvan-
tages and known interferences for each of the currently used analytical methods.
Foremost in our objectives has been 6 better understanding of the rel.iabil-
ity of various measurements which have been carried out. Since there are iither-
ent limitations in aU measurements, it becomes apparent that there are specific
needs for some indication of the reliability of the result. i.e., what is the
precision and accuracy of the reported value, and are these acceptable?
The volatility of most of the disinfectants makes sampling and sample
handling a major contributor to imprecision and inaccuracies. Stand.ard
addittons is a questionable technique; it should be avoided if possible, since
the pipettinig and dilution process causes potential loss of disinfectant.
The relative usefulness of each method, along with descriptions of known
interferences such as turbidity, organic matter, ionic materials, solids, color.
buffering capacity, as veil as the nature of the sample and the time between
collection of the sample and the actual analysis, are described in this report.
It must be emphasized, however, that almost invariably each of the methods
described is based n the total oxidizing capacity of the solution being
analyzed and is readily subject to interferences from the presence of ether
potential oxidizing agents and/or intermediates from concomitant chemical
reactions. Under ideal conditions some of the methods are accurate to bectet
2

-------
than ±1%- -especially in the absence of common interferences- -whereas other
methods are almost semi-quantitative in nature with many common species
interfering with both the precision and accuracy of the measurements.
We have also included chlorate ion as a residual species in that only
recently have reliable analytical methods begun to appear in the literature
(5,6,10). We also report on the chemistry of the chlorine-ammonia system and
the associated breakpoint reactions. because one of the most common thteferences
in the measurement of free chlorine is monochloramine.
The most important development for this report has been the decision to in-
clude a preliminary section describing an idealized” analytical method. The
need for this section became apparent as our writing progressed describing each
of the analytical methods for chlorine. Specific items included in this ideal-
ized method are accuracy, precision, reproduciblity. lack of interferences,
ease of use of the method, lack of false positive values, and so forth.
The benefit of the sidealizedu analytical method La to allow individual com-
parisons and to allow the choice between various methods based on individual
method shortcomings. For example, a particular method might have as its onLy
difficulty interference by manganese and iron. In many circumstances, this type
of interference might be a major problem. However, should the water supply
under consideration not have any manganese or iron, it is quite likely that the
method might be very usable- and as a matter of fact well mig it be the best
method of choice.
In other cases, speed of analysis rather than potential interferences (or
choice of some other important characteristic) might be the guiding factor in
choosing an analytical method. In this way rational choices can be made based
on potential and/or real difficulties and/or interferences and as compared to an
idealized method -. rather than a possibly controversial existing method.
Table I has been constructed as a quick reference guide to the available
methods for the determination of water disinfection chemicals and byproducts.
Included are pertinent analytical characteristics such as detection limits,
working range, interferences, accuracy and precision estimates. The current
status of the method, as gleaned from this report, is given. The necessary
operator skill level is given to aid the laboratory manager in assessing the
manpower requirements for a particular method. Additional information
concerning the reasons for the current status is contained in the Recommendation
Section of the Executive Summary and the complete report.
As each of the methods La described in detail in the full report, specific
conclusions are drawn- -along with appropriate recommendations--by comparing the
method against the idaalized analytical method for that species.
One additional benefit of this direct comparison is the possibility of add-
ing or subtracting a method to the list of Standard Methods for the E canination
of Water and (Jastevater (13), based on a rational set of criteria. It should
also be possible in the future to decide on the viability of various methods
based on their meeting specific criteria rather than based only on comparisons
between analytical laboratories (and personalized subjective reactions to the
various methods themselves
3

-------
TABLE I. CHARACrE.RISTICS AND
Specia5?
TYPE OF TEST MEASURED
(METHOD)t DIRECTLY
COMPARISONS
DETECTION
LIMIT
(i2g/L)
OF ANALYTICAL METhODS°
!JORKINC EXPECTED EXPECTED
RANGE ACCURACY PRECISION SKILl?
( g/L) (± %) (± %) LEVEL
Continuous Cl 2 + ROC1/OCl?
LODOMETRIC TITRATION:
Standard (Total Chlorine)
1.3 1.3 300 HR HR 3
O.O7
0.1 - 10 HR NR 2
‘ -c v
Q 354 0.5 - 10 HR HR 2
Black a d
Vhicrle Cl 2 + HOC1/OC1
Whittle &
Lapteff Cl 2 + HOCLfOCP
0.01
0.01
0.25-3 HF HR 1
0.25-10 HR 0-10 2
FREE CHLORINE
Ideal
Cl 1 + HOC1/OC].
0.001.
0.001 - 10
0.5
0.1
1
WV/VISIBLE
Cl 2 + UOCI/0C1
— 1.
1 - 100
HR
HR
3
AMPEROMETRIC
TITRATION:
Forward
Cl 2 + HOCI/OCl
O.0018&
0.02 - 0.032
>
>
10
10
NP
HF
NP
3 - 50
2
2
Back
Cl 2 + HOC1/0C1
0.002
>
10
3
•
50
HF
2
Continuous
Cl 7 + KOC1/OCl?
0.005
>
10
HR
1.0
2/3
DPD
FAS Tit’n
Cl 2 + HOC 1/0C1
O.OO4
0.01 - 10
NP
2
-
7
1.
0.Ol1
0.01 10
HF
2
•
7
1
Co1or’ tre
Cl 7 i - HOC1/OCl?
0.01’
0.0]. - 10 1 - 15
1.
-
14
2.
Steadifac
Cl 3 + HOC1/0C1
0.01’
0.01 - 10
HF
HR
1/2
4

-------
TABLE I. CHARACT ISTICS (contd)
saitir
REAGENT PRODUCTS INTERFERENCES
FIELD
pH RANGE TEST AUTOMATED
CUR NT
STATUS
5YRS >IDAY NONE
NA NA C1.NH 2 - C1 N
backgnd Abs
NA NA C1N , - C1,N
YES RECO (ENDED
NO RECO (ENDED
(LAB TEST)
NO YES CONT’D STUDY
Lyr 10mm
or .ess
Lyr lOam
or less
All oxidizing
species
A]1 oxidizing
species
pH Dependent NO
pH Dependent NO
NO RECO G(ENDED
(LAB TEST)
NO RECO? ENDED
(LAB TEST)
YES
NO
Independent
pH Dependent
pH Dependent
pH Dependent
pH Dependent
pH Dependent
pH Dependent
1-2
1-2
1-2
1-2
Ire
yrs
yrs
yrs
NA C INH 2 - CL,N
NA CLNR 2 - C 1 3 N
NA C LNU 2 - CL 3 N
NA C]N 4 2 C1 N
YES
YES
YES
YES
YES
YES
YES
YES
RECO?a(ENDED
RECO ’2tENDED
RECO ENDED
REC0Z0i DED
powder
30 mm
C1NR., - Cl,N
Requires
NO
NO
RZCO?*IENDED
stable’
ozid species
bu.tfer
(LAB TEST)
powder
30 am
ClN1f - C1 5 N
Requires
NO
NO
RECOt 4!NDED
sr.able
oxid species
buffer
(LAB TEST)
powder
s table
30 aLit
C1NH 2 - C1 3 N
oxid species
Requires
buffer
YES
NO
RECO D(ENDED
(FIELD TEST)
powder
stable
30 aLa
CLNH 2 - CL,N
oxid speciss
Requires
buffer
YES
NO
RECO tENDED
(FIELD TEST)
months
NR.
C INH , - cl ,N
oxid species
Requires
buffer
YES
NO
! 0N
months
NR
Oxidizing
species
Buffering
YES
NO
RECO?*IENDED
(LAB TEST)
S

-------
TABLE I. CHARACTERISTICS AND COMPARISONS OF ANALrrIcAL METHCDSG (coned)
Sp.ciea t DETECTIOH WORICING EXPECTED EXPECTED
TYPE OF TEST MEASURED UNIT RANGE ACCURACY PRECISION SKILL
(METH OD)I DIRECTLY ( g/L) ( g/L) (± 1) (± ) LEVEL
FACTS
Co1or 4 trc Cl, + HOCI/OC 1 .
0.1.
0.25 • 10
5 20
1
11
1
Spsctphoto Cl , + ROCL/0C1
0.012
0.05 10
NP
NR
1
METhYL ORANGE Cl, + HOCI/OC1
HR
HR
HR
HR
2
0-TOLIDINE Cl 2 + ROCL/0C1
HR
HR
HR
HR
1
3.3’-DIMEThYLNAPHTHIDINE
Cl, + HOCI/0C1
0.05
HR
HR
2
- 6
2/3
0-DIANISIDINE Cl , + HOCI/0C1
0.1
HR
HR
HR
2/3
cREMIUfl1 INESCENCE
Hydrogen
Peroxide Cl , + HOCL/OC].
HR
HR
HR
HR
3
Lu ir o1 0CL
0.0007
HR
HR
HR
3
Lophin. OCL
0.14
0.2 - 20
NB.
HR
3
ELECTRODE METHODS
Me bran. HOC ].
0.004
0.04 1
HR
1.6
3
1 tTh - C l , + HOCI/OC 1
0.1
0.]. - 3
NB.
1
25
3
Potsne erc C L , i HOCI/OC ]
0.005
0.01 - 1.
1 -
6
7
- 10
2
Agi
Volt’mtrc Cl, + HOC I/0C1
0.01
0.1 10
HR
HR
3
6

-------
TABLE 1. CHAPACTUISTICS (contd)
STA3ILIT FIELD CURR T
REAGENT PROD 3CTS INTERFERENCES pH RANGE TEST AUTOMATED STATUS
2 yeatsT 30 in Oxidizing Buffering YES NO RZCOtQ(ENDED
it high Cl 2 species critical
2 years’ 30 in Oxidizing Buffering YES NO RECO *1ENDED
at high Cl 2 species critical
N T NP Oxidizing Buffering YES NO ABANDON
species required
N T NP Oxidizing Buffering YES NO ABANDON
species required
NT 15.20 in Oxidizing HR NO NO ABANDON
species
HF 55 in Oxidizing HR NO NO ABANDON
species
NE <1 usc None Ind.penderit NO POSSIBLE ABANDON
HR l sic Oxidizing pli Dependent NO POSSIBLE CONVD STUDY
species
HR <1 sec Non. pH Dependent NO YES CONT’D STUDY
NA NA Oxidizing Dependent POSSIILE POSSIBLE CONTD STUDY
Cm.. species on pH
NA -a Oxidizing NP. POSSIBLE POSSIBLE CONT’D STUDY
species, C1
3 .onths NA Oxidizing pH Dependent YES YES RECO)V4ENDED
species C1
NA NA Oxidizing Buffer POSSIBLE POSSIBLE CONT’D STUDY
species, C1 required
7

-------
TA3LE I. OIAJ.AcrEazsncs AND cOMPARISoNs or MAL’frIcM. METHODSe (cont’d)
Spucisst DETECTION IJORICING PECTED CPECTED
TYPE OP TEST MEASURED LT.KIT RANGE ACCURACY PRECISION S1 II.L’
(METHOD)$ DIRECTLY ( g/L) (wg/L) (± %) (± %) LEVEL
TOTAL RIW
C]., + ROCL/0C1 0.001 0.001 - 1.0 0.5 0.1.
N}I,Cl N 4C1 , NC].,
AMPEROMETRIC TITRATION:
Forward Cl, + HOC 1/0C1 0.0018’ > 10 NP HF 2
NH ,C1 K}(CL , Nd,
Cl , + HOC1/0C1 0.02 .0.032 > 10 N T 3 - 50 2
NH,C]. NRC]., NC ] .,
Back Cl, + HOC I/0C1 0.002 > 10 3 - 50 HF 2
NR,C1 NRC]., NC ] .,
Continuous Cl, + HOCL/0C1 0.005 > 10 HR 1.0 2/3
NH,Cl NRC]., NC]., -
XODOMETRIC TITRATION:
Standard CL , + HOCL/0C1 0.07’ 0.1 - 10 NE NR 2
NH,Cl NHCI, NC]. ,
C l, + HOCL/0C1 0.35’ 0.5 - 100 HR HR 2
NH ,c]. NRC]., NC].,
DPD
FAS TLt’n Cl 2 + HOCL/OCV 0.004’ 0.01 1.0 NT 2 - 7 1
NH,C1 NRC]., NC].,
Cl 2 + ROC1/OC1. 0.11’ 0.01 - 10 NP 2 - 7 1
NH,C1 NRC]., NC].,
Color’acrc Cl., + HOd/OC r 0.00].’ 0.01 - 10 1 • 15 1. • 14 1.
NH 1 C1 NRC]., NC].,
LCV
Black 6
Whitti. Cl, + HOC1/0C1 0.005 0.25 - 3 NF 4 - 10
tiH,Cl HRC1, NC].,
8

-------
TABLE I . Q(ARACTUISTICS (cont’d)
STABILITY FIELD CURRENT
REAGENT PRODUCTS INTERFERENCES pH RANGE TEST AUTOMATED STATUS
5 IRS > 1 DAY NONE Independent YES YES RECO!2ICDED
of pH
1 - 2 yrs NA Oxidizing pH Dependent YES YES RECOtO (ENtE
Species
1. - 2 yrs NA Oxidizing pH Dependent YES YES RECOlct 1DED
Species
1 - 2 yrs NA Oxidizing pH Dependent YES YES RZCO)*tENDED
Species
1 - 2 yrs NA Oxidizing pH Dependent YES YES R1COt0(D ED
Species
1 yr 10 mm All oxidizing pH Dependent NO NO RECO?O4ENDED
species (LAB TEST)
2 yr 10 sin All oxidizing pH Dependent NO NO RECO ZQ IENDED
species (LAB TEST)
powder 30 sin Oxidizing Requires NO NO RECO )* ENT )ED
stale’ Species buffer (LAB TEST)
powder 30 tin Oxidizing Requires YES NO R&COIOID OED
stable’ Species buffer (FIELD TEST)
powder 30 sin Oxidizing Require. YES NO RECO)QWThED
stable’ Species buffer (FIELD TEST)
onths HR Oxidizing Requires YES NO ABANDON
Species buffer
9

-------
TAZLE I. Qt RACTUISTICS AND COMPARISONs OF ANALYTICAL METHODS 0 (cont’d)
Speciest DETECTION VOEXINC PECTED CPECTED
TYPE OF TEST MEASURED LIMIT RANGE ACCURACY PRECISION SKILL’
(METHOD)t DIRECTLY ( g/L) ( g/L) (± %) (± %) t.EVEL
Whittle 6
Lapteff Cl 2 + HOCI/0C1 0.01 0.25 10 NF 6 - 10 2
NN 2 C1 NHC I 2 Nd 3
FACTS
Coler’mtrc C L 2 + HOCL/0C1 0.1 0.25 10 5 - 20 1. - 1]. 1
NB 2 C1 NBCI. 2 Nd,
Spect’phoco C l 2 + HOCI/0C1 0.012 0.05 - 10 NT t R 1
Nli ,CL NHCL, MCi,
ELECTRODE METHODS
Pot’ ecric Cl , + HOC1/0C1 0.005 0.01 - 1 1. - 6 7 - 10 2
tlH ,C1 NHCL, MCi,-
MoNoaaoaA1( 1NE 9
1d.&1 NH ,Ci 0.001 0.001 - 10 0.5 0.1. 1
UV/VIS IBLE HR ,C1. — 1 1 - 100 HR MR 3
AMPEROtTrRIC TITRATION:
Forward NH 2 C 1 NR > 10 NT 0 - 1.0 2
lack NH,Ci HR >1.0 07 OF 2
DPD
FAS Tit’n NH ,C3. HR 0.01 . 10 07 2 7 1
Co1or’ crc HH ,CI MR 0.01 - 10 HF S - 75 1
10

-------
TABLE I. aiAPACTERIS’rICS (eont’d)
ontha NR Oxidizing
Species
B1.Lfferthg YES
NO LECO C EN EDD
(LAB TEST)
2YRS 3O in
at high
C l 2
2YR.S 3O in
at high
Cl,
3 onths NA Oxidizing
Species, C1
pH Dependent YES
YES RECO Q ENDED
5YRS >LDAY
NONE
Independsnt YES
YES RECO1 DtENDED
NA
NA Cl ,NH - Cl,N
backgnd Abs
pH Dependent NO
NO IECO?’QIENDED
(LAB TEST)
1-2 yra NA Cl ,K4 Ct,tI
pH Depandane YES
YES RECO? DED
1-2 yrs NA C1,NN . C1,N
pH Dep.ndsne YES
YES RECO (END ED
STAZIUT( FIELD CURRENT
REAGENT PRODUCTS INTWERENCES pH RANGE TEST ALrrOMATED STATUS
Oxidizing
Buffering
YES
NO
RZCO *(ZNDED
Species
n ritica .
Oxidizing
Buffering
YES
NO
RECO CtENDED
species
crt ical
powder
stable’
30
ath
CINH ,
oxid
- C1 1 N
species
Requires
buffer
NO
NO
RECO O(ENDED
(LAB TEST)
powder
stable’
30
mm
CINN,
ozid
Cl ,N
species
Requires
buffer
YES
NO
RECOHMENDED
(FlE1 D TEST)
11

-------
TABLE t. CHARACTERISTICS AND COMPARISONS OF ANAL’fIICAL METHODS 0 (conc’ d)
Spiciest DETECTION WORXINC EXPECTED EXPECTED
TYPE OF TEST MEASURED LIMIT RAJiGE ACCURACY PRECISIO& SKILL’
(METHOD)’ DIRECTLY (mg/I.) (mg/L) (t %) (± 1) LEVEL
LCv
Whittle & NH 2 CL NR 0.25 - to HF 0 - 43 2
L p eff
ELECTRODE METHODS
Silver iodide
Vo1ta .tric NE Cl HR 0.1. - 10 HR HR 3
Dt .OBAMINE’
1d.a1 NRCI 2 0.001 0.001 - 10 0.5 0.1 1.
S
UV/VISThLE NHC1 2 — 1. 1. - 100 HR HR 3
AXPEROMETR.IC TITRATION:
Forward NEC I 3 KR > 10 NE 0 2
lack HHCI, HR > 10 3 - 50 NP 2
DPD
FAST It ’n NHC 1 2 HR 0.01-10 NE NP 1
Co1or mtxc DCl, HR 0.01 - 1.0 NP 0 100 1
LCV
0.25 10 HF 10 150 2
Lapt.ff
12

-------
TABLE I. CHARACTERISTICS (cont’d)
STAB ILITY FIELD CURRENT
REAGENT PRODUCTS INTERFERENCES pH RMGE TEST AUTOMATED STATUS
months NR Oxidizing Requires YES NO RECO * ENDED
species buffer (LAB TEST)
NA NA Oxidizing Requires POSSIBL.E POSSIBLE CONT’D STUDY
species buffer
5 YES > 1 DAY Independent YES YES RECO O(ENDED
of pM
NA NA CINU, & Cl N pH Dependent NO NO RECO ENDED
baekgnd Abs (LAB TEST)
1-2 yrs NA CLNU 2 & Cl,N pH Dependent YES YES RECO tENDED
1-2 yrs NA CU H & C1 N pH Dependent YES YES RECOMMENDED
powder 30 in CINH, & C1,N Requires NO NO RECOMMENDED
stable’ ozid spsct.. buffet (LAB TEST)
powder 30 sin C1NH 2 & C1 3 N Requires YES NO RECOMMENDED
atab le ozid species buffer (FIELD TEST)
sonthe NR Oxidizing Requires YES NO RECOMMENDEDD
species buffer (LAB TEST)
13

-------
TA$LE I. CNfl RACTERISTICS AND COMPARISONS OF ANALYTICAL METhODS 1 (cont’d)
Sp.cie3 t DETECTION WORICING EXPECTED EXPECTED
TYPE OF TEST MEASURED LIMIT RANGE lcCtCY PRECISION SKILl?
(METhOD)I DIRECTLY ( g/L) ( g/L) (± I) (± 1) LEVEL
TRIQil R ’
NC ] 3 0.001 0.001 • 3.0 0.5 0.1
UV/V’ISIBLE NB NB NR 3
AMP 0METRIC TITRATION:
Forward NC ] 3 NB > 10 NF S - 1.00 2
DPD
FM Tit’n NC ] 3 NB 0.01 - 10 NB NB I.
Co1or mtrc NC ]. 3 NB 0.01 10 NB NB 1.
LCV
Whittle 6 NC]., NB 0.25 10 NB NB 2
Lapteff
QUORINE DI DE
14ma1 dO, 0.001 0.001 - 10 0.5 0.1 1
IOD O M ETS.IC C].0 , 0.002 0.002 • 95 1 - 2 1. - 2 2
AMP OMETRIC dO, ’, 0.03.2 0.02 7? 3. 3.5 1. - 15
C10,10.lt 0.008 0.008 - 20 10 7 15 2
W I
Manual ClO, 0.05 0.05 - 500 5 5 2
FIA ClO , 0.25 0.25 • 142 2 1. 1
14

-------
TAZLE I. cHARACT lSTICS (cont’d)
SYRS >IDAY
NONE
!nd.pend.nt YES
YES R.ECO}OcDDED
NA NA C1NR C I 2 NH
backgnd Abs
HOCL/0CL
pH Dependent NO
NO RECO! ENOED
(LAZ TEST)
YES RECO O DED
(LAB TEST)
YES NO RECO tENDED
(LAB TEST)
5YRS >1DAY NONE
1 YR Subject to Oxidizing
oxidation sp.ci.s
good Subject to Metal ions &
oxidation nitrite Len
YES RECO1 iDED
NO NO NOT &ECO (D ED
STABILITY
REAGENT PRODUCTS
INTERFERENCES
FIELD
CURRENT
pH RANGE TEST AUTOMATED STATUS
1-2 yrs
NA
CUfl , - C1 2 UH
pH Dependent NO
povdar
30 in
C1NR 2 - C1 2 NH
R..quir.e
stable’
oxid species
buffer
powder
30 ath
C1.NH 2 - C1*NH
Requires
stable’
ozid species
bt&ffer
aonths
HR
Oxidizing
species
Requires
buffer
NO NO R1CO O( DED
(LAS TEST)
YES NO RECO OtENDED
(LAB TEST)
solid
stable.
<30 aiw OziAI ing
species
Other ( IV
absorbers
Independent YES
2-5
7 NO P lO CUP.RENTLYUSED
7 NO NO NOT RZCO QtE21DED
Ictd.psndent NO YES RECOPUtENDED
(LAB TEST)
Indsp.nd.nt NO YES RECOMMENDED
(LAB TEST)
none none non.
15

-------
TABLE I. CHARACTERISTICS AND COMPARISONS OF ANAL’ITICAL MZTHODSC (coned)
SpecLe DETECTION i0RKINC EXPECTED EXPECTED
TYPE OF TEST MEASURED LIMIT RANGE ACCURACY PRECISION IKILL’
(METMOD)l DIRECTLY (mg/L) ( g/L) (± %) (± 1) LEVEL
A CVX 12 cia 2 0.04 0 - 25 NR NP. I
CHLOROPHENOL RED dO 2 0.003 0.003 - 1 10 5 1.
o-TOUDINE ClO, 0.1 NP. NR NP. 3.
INDIGO EWE C10 2 0.01 NR NR 1.5 1
C2iEt IWMlNESC CE
L*inol dO, 0.3 0.3 - 1 NR 8 1
CDFL ” C1O. 3 0.005 0.005 74 2 1 1
ELECTROCHEM.
Pt Hicroelec. dO, + C1O , 1.3 NR 7 R 2/3
Vit. Carbon dO, 32 NP. NR NP. 3
Vo1 a . Hew. dO, 0.25 NR NP. 2
Rotating Volt.
Membrane ClO , 0.30 0.30 - 3 NP. 6.4 2/3
QR .ORITE ION
C10 , 0.001 0.001 - 10 0.5 0.1 3.
MPER OMETRIC
Iodowetric 0.05 0.05 95 5 5 2
1oDo frrRIc
Sequer tiai. C10 , 0.011 > 1 1 2. 3
HodLEied C1Q , 0.3 0.5 - 20 0.5 1 - 3 3
DPD C1O, 0.01 0.01 - 10 5 5 2
16

-------
TAZI.E I. CHARACTERISTICS (cont’d)
STABIUTY FIELD CURRENT
REAGENT PRODUCTS INTERFERENCES pH RANGE TEST AI.TIOHATED STATUS
HR HR inima1 8.1 - 8.4 NO NO CONT’D STUDY
6 oonths HR unknown 7 YES NO NOT RECOZOIENDED
HR HR Oxidizing HR NO NO NOT RECOIO(ENDED
species
good good O Cl 2 > 4 NO NO NOT RECO D DED
1 DAY < 1 sec HR NR NO NO NOT RECO?Q ZNDED
I DAY < 1 sec Cl ., > 12 NO YES RECO *tENDED
CONT’D STUDY
none none C lO , - S - 55 NO NO CONT’D STUDY
none none CLO , 3.5 - 7 NO NO CONVD STUDY
none none NOd 7.8 NO NO CONT D STUDY
none none HOC ] 5 - 5.5 NO NO CONT’D STUDY
5 YRS > 1 DAY NONE Independent YES YES RECO (ENDF.D
1 YR Subj eec to Oxidizing 2 - S NO NO NOT RECO *(ENDED
oxidation species
good Subject to Metal ion. , & 7 NO NO RECO?*(ENDED AT
oxiditien nitits Len HIGH CONC.
good Subject to Metal ions & 2 NO NO CONTD STUDY
oxidation nitic. ion
Solid < 10 sin Oxidizing 7 NO NO NOT RECO CiENDED
etable species
17

-------
TABLE I. CHARACT IST1CS AND COMPARISONS OP ANALYTICAL METhODS 0 (co r!d)
Speciest DETECTION WORXINC EXPECTED EXPECTED
TYPE OF TEST ME . SURED LIZIIT RANGE ACCUP .ACT PRECISION SKILL
(HEThCD) DIRECTLY (ag/L) ( g/L) (± %) (± %) LEVEL
c U ..ORATE ION
‘Id.e al C10 3 0.001 0.001 - tO 0.5 0.1 1
IODOMETRIC
Sequential C1 0 3 0.064 > 1 2 2 • 5 3
Modified C10 3 0.3 0.3 20 1. 1 - 3 3
FIA C 10 3 0.08 0.08 - 0.8 3.5 1 2
DPD C10 3 0.01 0.01 - 10 5 5 2
OWNE
Idaa l’ 03 0.01 0.01 10 0.5 0.1 1.
IOD OflETR .IC 03 0.002 0.5 100 1. - 35 1 - 2 2
ARSENIC RACK
TITRATION 0 0.002 0.5 - 65 1 - 5 1. - 2 2
PACTS 03 0.02 0.5-5 5-20 1-5 2
DPD 0 , 0.]. 0.2 - 2 5 - 20 5 2
INDIGO
Spact’pboto — 0 0.001 0.01 - .1 1 0.5 1
0.006 0.05 - .5 1 0.5 1
0.1 >0.3 1 0.5 1
18

-------
TABLE I. CHARACT lST1CS (contd)
STAEIUTT FIELD
REACENT PRODUCTS INT FER.ENCES pH RANGE TEST AUTOMATED STATUS
5 YRS > I DAY NONE Independent YES YES RECO 2iENDED
good Subject to Metal ions & 7 NO NO RECO ENDED AT
oxidation nitrite ion HIGH CONC.
good Subject to Metal ions & 2 NO NO CONT’D STUDY
oxidation nitrit, ion
1 year I day Oxidizing < I NO YES USED A.flER ALL
species dO 2 ClO , CONE
Solid < 30 in Oxidizing 7 NO NO NOT RECO EiDED
scable species
3 YRS > 1 DAY NONE Independent YES YES F.ECO ENDED
1 YR subject to All ozone < 2 NO NO ABANDON
oxidation by products
and oxidants
1 YR subject to Oxidizing 6.8 NO NO CONT’D STUDY
oxidation species
2 YRS no fading Oxidizing 6.6 NO NO NOT RECO?O(fl DED
first 5 sin species
SoLid < 30 sin Oxidizing 6.4 NO NO NOT RECOPOiENDED
sr.ab le species
good josd Cl ,. Mn ion.; 2 NO YES RECO?NVqDED
• Br ,!,
good $ood Cl 2 , Mn Lena 2 NO YES RECOPO4ENDED
Br, I ,
good good Cl ,, Mn ions 2 NO YES tECO)*IENDED
Br 2 12
19

-------
TABLE I. c)tARACTUISTICS AND COMPARISONS OF ANAL’ITICAL METhODS 0 (cont’d)
Spec teat DETECTION WORKING PECTED CPECTED
TYPE OF TEST MEASURED LIMIT RANGE ACCURACY PRECISION SKILL’
( ME T hOD) $ DIRECTLY (og/L) (0g/L) (± %) (± t) LEVEL
INDiGO (cont’d)
Visual. 03 0. 1 0.01 0.1 5 5 1
>0.1 S S I
CDFIA O 0.03 0.03 0.4 1. 0.5 2
other ranges
possible
LCV 03 0.005 NR MR MR 1
ACVK 0 0.25 0.05 - I HR MR 1
o-TOUDINE 03 NOT QUANTITATIVE MR. MR 1
BISTERPYRIDINE 0, 0.004 0.05 20 2.7 2.1 3
CARMINE INDIGO 03 < 0.5 HR MR I.
ELECTROC}IEM
Aapero stric Total — 1 5 5 2
oxidant a
A psroeetric
iodoi .tric Total — 0.5 MR 5 5 2
Oxidanta
Bare electrode O 0.2 NT 5 5 2
Meebrwiis elect. O 0.062 NP 5 5 1.
Dtffer.utis l
Pulse Dropping
Mercury 0 , HR HR HR. MR 3
Dtfferer tta1
Pulia Polar.
ography 03 0.003 HR HR HR 3
Pocenrio etrtc 0, 1JR KR 1.
20

-------
TABLE I. CHABACT 1STtCS (cont’ d)
STABILITY
REAGENT PRODUCTS
FIELD
TEST AUTOMATED
good good
S ab1e
MR
MR
Good
Stabi.
MR
MR
Good
1 YR Subject to
oxidation
none NR
nons MR
Cl ,, Mn ions
Br, 19
Cl ,, Mn ions
Br, 12
Cl, at > Lng/L
S’ S0 1 Cr’
Mn> 1 mg/L
Cl, > 10 og/L
M.tal ions, NO
Cl 2
Oxidizing
.p.ctu
MR
MR
NO RECO? (ENDED
NO RECOl ENDED
NO YES COMPARISON
STUDIES
NEEDED
NO NO CONT’D STUDY
NO NO CONT’D STUDY
MR NO NO RESEARCH LAB
4 NO MO NT’D STUDY
MR NO YES CONT’D STUDY
INTERFERENCES pH RANGE
good
good
good
good
STATUS
YES
YES
2
2
2
2
2
NR MR MR
none NA Oxidizing
species
2
<
7
NO
YES
RECO Q(DItED
(LAB TEST)
2
NO
NO
CONT’D STUDY
2
NO
YES
RELATIVE
MONITORING
4 4.5
NO
NO
NOT RECOP ENDED
HR
NO
YES
CONT’D STUDY
non. it
non.
none
MR
MR
21

-------
TABLE I. CHARACTERISTICS AND COMPARISONS OF ANALXTICAL. METHODS 0
Speciest DETECTION WORKING DCPECTED EXPECTED
TYPE OF TEST MEASURED LIMIT RANGE ACCURACY PRECISION SKILL’
(METh0D) DIRECTLY (ogfL) (og/L) (± %) (± %) LEVEL
uv O 0.02 > 0.02 0.514 0.5
ISOTHER MAL
PRESSURE CHANCE 0, 4 x 10 4 x 10 - 10 0.5 0.5
OZONE GAS PHASE
Idsai 0, 1 1 50,000 1 1
UV 0, 0.5 0.5 - 50.000 2 2.5
S tripp thg
Absorption
Iedc .try 0, 0.002 0.5 - 100 1 - 35 1. - 2 2
Che i1 inescenca O 0.005 0.005 1 7 5 1/2
Gas phase titration 0, 0.005 0.005 - 30 8 8.5 2
Rhod.anine 8/
GaI .lic Acid 0, 0.001 NR 5
A psro n ctry 03 NE KR HR KR
O for page nunberi in the full report, refer to the Alphabetical. Index
t direct d.t.rathation of the specie. ea.aured vithaut interferences
• Operator Skill Levels: I — ainisi.1, 2 — good technician,
3 — experienced chesist
NA Not applicable
HR Not reported
NY Not found
1 Using research grads slectrochesical oquipi.nt
2 Using ce ercia1 titrator
3 Spsctrophotosstric endpoint detection
4 VIsual endpoint dateetion.
5 Using test kit
6 Liquid reagent is unstable
7 Stablility is very dependent on the purity of the 2-propanol . used
22

-------
TABLE I. CI3AP.ACTEP.ISTICS (cont’d)
STABILITY FIELD
REAGENT PRODUCTS INTERFERENCES pH RANGE TEST AUTOMATED STATUS
none NA Other Independent NO YES ESTABLISH
Absorber MOLAR AZSOP-
TIVITY
none good none Independ.ent NO YES COMPARISON
STUDY
none none none Independent YES YES RECO ENDED
none none none NA YES YES RECO iENDED
good good SO 2 NO 2 NA YES NO ABANDON
stable < 1. sec none NA YES YES RECO 2 !NDED
stable stable none NA YES NO NOT RECO ZNDED
problems YES POSSIBLE NOT RECO ENDED
none none NR NA YES YES NOT RECO ENDED
8 Total. Chlorine is all, chlorine species with +1 oxidation state
9 Vary little actual work has been carried our on selective determin.ation
of chloramines. The values reported are from extrapolated studies that
had objectives other than the selective determination of chloramthes.
Most methods are indirect procedures which are not recommended
10 Indirect method
II 1/5 of C10 2 determined
12 Acid chrome violet potassium (ACVIC)
13 Gas diffusion flow injection analysis (GDFIA)
14 Based on current molar absorbtiviey cr4 proper sample handling teeniques.
Current best ostimates of molar a.bsorbtiviry of 2900.3300 give a
possibis error of ) 10%.
C Taken from Cordon. Cooper. Rice. and Pacey, AWA.RF Reviov on
Disinfectant Residual Measurements Methodsu (1987)
23

-------
Chapter 4 (Indexed Reference Citations) has been included in this report in
order to assist readers in locating particular papers of interest. The 48
categories for chlorine, chloramines, and the oxy-chiorine species, along th
the additional 60 categories for ozone, should make the cask of finding n-
dividual papers of interest considerably less cumbersome. Papers which descr .be
several methods have been included in each of the appropriate categories. All
together, the 1,400 references cited in Chapters 1.3 number more than 2,CO0
individual citations when distributed in the indexed form of Chapter 4.
Chapter 5 is an alphabetical listing of the thdividuaJ. references citations
Finally, a detailed Index has been included in order to assist readers n
locat .ng subjects of specific interest. We hope the readers will find these
additional chapters as useful as have we in preparing this report.
R C0M C DATI0NS
General Statements on Comparisons.
There have been and will continue to be reports of inethod.s comparison. One
of the most important considerations for a method is accuracy, i.e. the ability
of the method to determine the correct concentration of a di jnfecta t in
solution. An equally important consideration is precision, i.e. how veil does
the analytical method reproducibly measure the same concentration. Frequently
experiments are conducted to determine the “equivalancy of the methods. From
such results, methods may be found to be equivalent, but the only analytical
ccnsiderac ons tested were accuracy, as judged by a Referee Method, and
precision, judged for each method based on the experimental design.
No considerations were given to specificity or analyst preference. Yet erie
of the most difficult tasks in the area of disinfection analytical methods
development is comparison testing. It is recommended that a protocol be
developed to initiate comparison of the disinfectants. This protocol should
include all of the factors delineated in the Idaal Method and should be
undertaken in both laboratory controlled conditions and at selected water
treatment plants around the country.
chlorine Chemistry.
Clearly, the conversion to moles, equivalents, or normality from units of
mg/I. (as Cl 2 ) or mg/L (as other oxidants) can easily be confused (and
confusing). Our recommendation is that all, oxidizing agents be reported in molar
units (M) and, if necessary, in mg/L of that oxidizing agent as measured (i.e.
mg/L (as Cl 2 ) or mg/I. (as C10 2 ) or mg/I. (as ClO, ’). Furthermore, we recommend
that oxidizing equivalents per mole of oxidant be reported to minimize
additional potential confusion. For example, when CLO, is reduced to ClO ,
this corresponds to one equivalent/mole; on the othet hand, when C10 2 is reduced
to CP, this corresponds to five equivalents/mole. A summary of molecular
weights and oxidizing equivalents for the various chlorine species, oxychlorine
species and ozone is given in Table II.
24

-------
TABLE I I. EQUIVALENT WEIGHTS FOR CALCULATING CONCENTRATIONS ON THE
BASIS OF MASS.
Molecular Equivalent
\Jeight Electrons Weight
Species g/mol Transferred g/eq
Chlorine 70.906 2 35.453
Moncchloramine 51.476 2 25.736
Dichloramine 85 921 4 21.480
Trichloraoine 120.366 6 20.061
Chlorine dioxide 67.452 1 67.452
Chlorine dioxide 67.452 5 13.490
Chlorite ion 67.452 4 16.863
Chlorate ion 83.451 6 13.909
Ozone 47.998 2 23.999
Ozone 47.998 6 8.000
Several mechanLsms have been proposed for the decomposition of dtchloraxnine,
but the complete mechanism at the breakpoint has not been resolved. Clearly, the
chemistry LS complicated and varies markedly with solution composition. A
detailed understanding of the specific reactions involved requires a detailed
knowledge of the concentration of all chloramsno species in the system.
Nitrogen-containing organic compounds may be present in surface water and
ground-water. Because of analytical complexities, very few detailed studies
have been undertaken to determine the individual compounds present and the
concentration at which they exist. Kjeld.ahl nitrogen analysis is used
frequently, but this does not provide any detailed information with regard to
individual compounds. The area of organic nitrogen and the determination of
specific compounds in natural waters is one of the increasing interest and
requires considerably more research in characterization and methods development.
Ultraviolet Methods.
In general, because the molar absorptivities are quite low for chlorine and
chioramine species, ultraviolet methods are not considered useful in routino
monitoring of chlorine residuals. In addition to the low molar absorptivities,
there is often background absorbance chat may interfere with the measurement in
various natural waters. However, these measurements are of use in standardizing
the chlorine species in distilled waters and are often eased in experimental work
25

-------
related to chlorine speciacion. This method does have considerable potential
for the determination of reLatively high concentrations of halogens ,
particularly in relatively clean water. This method might find use in
monitoring chlorine species in water treatment plants. However, with a more
elaborate multiwavelengch speecrophotometer and computer-controlled spectral
analysis, it might be possible to analyze several halogens simultaneously.
It is also possible that additional methods using permeable membranes could
be developed for the simultaneous determination of chlorine species in aqueous
solution. Additional work is necessary in this area. Although the molar
absorprivities of the species is not of a magnitude as to lend it to the routine
determination of the dilute (less than lO M) chlorine and chlorirte-arnmonia
species, it is potentially helpful in determining the concentration of standard
solutions. Absorption speccrophotometric analysis has and will continue to be
very important in the area of chlorine chemistry. It can be used in the
unambiguous determination of relatively high concentrations of the species in
relatively pure water.
Continuous Amperomecric Titration Method.
Interferences appear to be reduced using the continuous amperemetric method
because the reagents are added to the sample Just prior to contacting the
indicating electrode. Thus, when compared to the amperomecric titration, the
amount of interference by iod.ac. ion, brom.ace ion, copper(II), iron(III), and
manganese(IV) is reduced by approximately one-tenth. No reports appear to be
available in the literature -on the determination of mixed oxidants using the
amperometric method. Such experiments need to be carried out. In addition, few
experiments have been reported which clearly demonstrate chat the electrodes
remain uncontaminated for drinking water or waste water systems. In the absence
of such comparisons, the accuracy of any electrode procedure may be
questionable.
However, the amperomecric titration determination of chlorine species re-
mains the standard for routine laboratory measurements. Given proper analyst
training and experience, the commercially available instrumentation is sensitive
and precise. This method should remain as the method for laboratory use and
accuracy comparisons. It requires more analyst experience than colorimetric
methods, but can be relied on to give very accurate and precise measurements.
It should be noted that care must be exercised when using one titrator for the
measurement of both free and combined chlorine. Small quantities of iodide ion
can lead to errors when differentiating between free and combined chlorine.
Careful rinsing with chlorine demand free water (CDF J) La a must! Additional
development of automated back-titration equipment with the goal of lowering the
limit of detection and improving the reproducibility would be highly beneficial.
Iodomscrjc Titration Method.
The Lodometric titration La useful for determining high concentrations of
total chlorine. The most useful range is 1 mg/L (as Cl 2 ) or greater. It is a
common oxidation-reduction titration analytical method and provides a reference
procedure for total. chlorine. Although not necessarily used routinely, most
laboratories use it as a reference method and it is net likely ever to be
eliminated from use.
26

-------
Colorimetrjc Methods.
It is reported in Standard ethod (13) that nitrogen trichioride can be
measured using the DPD method; however, the method has not been confirmed by
independent investigations and should be used only as a qualitative method.
Additional research is necessary to determine the sffectLveness of the DPD
method for nitrogen trichioride. The effect of the presence of mercuric
chlotide in the reagents for minimizing the breakthrough of monochioramine into
the free chlorine reading with the DPD method has been shown. It is very
important that the addition of mercuric chloride to the buffer be followed to
minimize the direct reaction of monochioramine with DPD. This phenomenon is not
thoroughly understood. This effect should be studied more thoroughly and the
principle may be applicable to all of the colorimetric methods.
The use of thimacetamide was evaluated for monochloramine (using DPD-
Steadifac). It was shown under these conditions to elimirLace any positive
inteference in the free residual measurement. These results are not as yet
understood, but the implication is that the chemistry of oxidation is different
for monochloramine and free chlorine. These results suggest that more work is
necessary to better define the reactions involved, and this may lead to a more
usable analytical procedure. This procedure is recommended for use in waters
that are suspected to be relatively high in combined chlorine.
The DPD-Ethyl Acetate Extraction Procedure is a modification of the DPD
chemistry. The method is based on the oxidation of iodide ion by active
chlorine followed by extraction of the iodine species into ethyl acetate. This
procedural modification may be of use in the determination of total resith. al
chlorine in both the field and laboratory. Additional work is necessary before
it can be used to any great extent. It does not appear to offer substantial
advantages to the already well tested colorimetric method for laboratory
measurements.
The DPD methods have become the most widely used procedures for the measure-
ment of chlorine. This is not Likely to change. The DPD color reagent, in
liquid form, has been shown to be quite unstable and is not recommended for use.
It is sensitive to oxidation by oxygen and thus requires a control measurement.
Clearly, it is better to use dry reagents.
Leuca Crystal Violet. LCV.
No studies have been reported that examine the interference of chlorine
dioxide and/or ozone in the LCV method. It is anticipated that these oxidants
would interfere in th. method, and studies should be conducted to quantify these
potential interfe rents.
Syringaldazine; FACTS.
A study using syringaldazine in a continuous method to differentiate free
from combine chlorine has been reported. It vas concluded that it could be used
and was useful in controlling free chlorination. Futther work would have to be
conducted to use this or any colorimetric method in continuous analyzers.
27

-------
Q emi luminescence.
Several papers have appeared that detail the reaction of hydrogen peroxide
and hypochiorous acid and the resulting chemiluminescence. The mechanisn has
been relatively well established and the chemilusiinescence is thought to occur
as a result of the formation of singlet oxygen. The light emitted is red (635
nm), and occurs most readily in alkaline solution. This reaction is rather
insensitive to low concentrations and is not suitable for the determination of
hypochiorous acid in aqueous solution. However, the studies that have been
reported can serve as a guide for those interested in pursuing other methods for
the determination of hypochiorous acid by chemiluminescence. It is not sensitive
enough to be considered as an analytical method for chlorine in water treatment.
A study has been reported that details the use of luminol for the
measurement of hypoch] .orite ion. The optimum pH for analysis was between 9.0 and
11.0 Luminol also has been used for the determination of hydrogen peroxide.
,5,6 ,7,.cecramethoxy1uminol is 30 s more sensitive than luminol. Either of
these compounds may be more sensitive in the determination of free chlorine. As
these compounds have not been tried it appears that additional studies are
necessary. From the limited data available, it appears that this reaction has
considerable promise as an analytical method. It may very wel]. be the most
sensitive method to date.
It is reported that lophine, in a reaction with hypochlorite ion, produces
light. Very few details were given in the study for this reaction. It appears
that lophine also may be good as. a chemiluminescence reaction system for free
chlorine. Additional work should be undertaken to better criaracterize the
details of this reaction.
Luminol and some of its derivatives, or Lophine, may be well suited for the
very sensitive measurements of chlorine species. Additional research should be
undertaken to develop the use of chemiluminescence for use in the determination
of chlorine in water. The potential exists for rapid, simple, and specific
methods for chlorine and possibly other oxidants. With the advent of fiber
optic sensors and their application in chemiluminescence methods, this
technology will be important in the future.
Fluorescence.
The use of rhodanine 5 has been reported as a low level fluoromerric method
for the determination of bromine. This method ii qualitatively specific for
bromine, although chlorine will react to decrease the fluorescence. The advant.
age of this method is that it is capable of determining oxidants at very low
concentrations. This method could be applied to chlorine analysis by first
using the frss chlorine to oxidize the bromide ion to bromine, an irreversible
reaction, foUowed by the determination of bromine. This method was not
developed fully and very little work has been undertaken since the first
publication. It does appear to have considerable potential and future research
in the area of methods development should not exclude additional work on this
fluorometric procedure.
28

-------
Other Electrode Methods.
Additional studies are required to better uhderstand the limitations of
membrane electrode methods. It appears that they may have prominent roles to
play in chlorine residual measurements in the future.
In a series of experiments carried out for the determination of free
chlorine in tap water, it was observed that there was a statistically
significant difference between the results of the asperometric titration and the
membrane electrodes. It was thought to be a problem in the membrane electrodes
However, on reconsLderation, it is possible that the electrodes were accuai].y
giving a free chlorine reading and the amperometric titration was reading the
sum of free and organically combined chlorine. The study was conducted on water
which is relatively high in organic nitrogen. ‘It is possible that considerable
chlorine is present as organically combined chlorine and interferes in the
amperometric titration procedure, but does not interfere with the membrane
electrode measurements. This question must be resolved. Carefully designed
experiments to expicitly resolve these differences would be most appropriate.
There have been no reports of experiments using bare-electrode amperometric
analyzers where other oxidants such as chlorine dioxide, chlorite ion, chlorate
ion or ozone have been tested with the bare-electrode, Additional studies are
required to expand these bare-electrode amperometrie studies to quantitate
interferences with oxidants other than those tested, and to expand to other
natural waters.
Since the accuracy of the potentiometric electrodes is affected, if
temperature corrections are not used, it is recommended that temperature be
either controlled or measured simultaneously. Additional independent measure-
ments of accuracy should be undertaken for the potentiometric electrodes.
It appears that the potentiometric electrode can be used for the
determination of total residual oxidant. It is suitable for continuous
measurements and appears to give results that are acceptable when compared to
the amperometric titrator.
General Stary and tecotnsnttions for chlorine.
In comparing all of the methods to the “Ideal Method ” we find that none come
very close to our ideal standard. Continued development of the various methods
will, however 1 come closer and closer to the ideal.
For the present, the emperometric titration techniques will remain the
laboratory standard used for the basis of comparisons of accuracy. These
methods, with proper precautions can differentiate between the common inorganic
chorine/chlorine ammonia species, and in general suffer from as few inter-
ferences as any of the methods.
Of the three common colorimetric procedures, nfl, T,,CV, and FACTS, the DPD is
by far the most commonly used method. From the available literature it is clear
that the CPD procedure has a number of weaknesses. Zn particular, the colored
product is a free radical which limits the stability of the colored reaction
product. The direct reaction with monochloraaine, to form a product identical
29

-------
to the reaction with free chlorine, is also a drawback. This problem can be
reduced by the addition of thioacetamide. Liquid reagent instability precludes
their use in most cases; care should be taken to determine blanks frequently.
The present L.CV method that appears in Standard Methods (13) is outdated and
has been substantially improved upon by Whittle and Lapteff (14). This method
allows for the differentiation of the common free and combined inorganic
chlorine species. However, because only one comparison study has been
conducted, ad4itional collaborative testing is recommended.
The FACTS test procedure .ppears to be very useful for the determination of
free chlorine in the presence of relatively high concentrations of combined in•
organic chlorine. A severe drawback of the FACTS test procedure is the irtsolu-
bility of the syringaldazine in either 2-propanol or water. This leads to dif.
ficulties itt reagent preparation, and presumably to the color stability problem
encountered at the higher concentrations of chlorine (greater than 6 - 8 ng/L
(as Cl 2 )). Although a method for the use of the FACTS test for total chlor ne
has been reported, it should be tested further.
Electrode method.s have been developed amploythg several different cenceots.
The membrane electrodes appear to have potential as specific methods for hypo-
chiorous acid. Common interferences are other riorU .onLzed molecules such as
chlorine dioxide and ozone. Potentiometric electrodes fur the determination of
total chlorine are improving in both detection unit and stability. These
electrodes appear to have promise in the area of process control. Their
inclusion as methods for routine use in the laboratory and field is warranted.
Both fluorescence and chemiluminescence methods also show promise for the
specific determination of free chlorine at very low concentrations. JichLn ch .s
area of speccrofluorometric methods, there is considerable work vet to be
initiated. Continued development work is warranted and recommended in thi s
promising area.
From the review of analytical procedures for the determination of chlorine
in aqueous solution, it is readily apparent chat only a few of the methods are
used routinely. Nevertheless, there is certain to be a continued interest in
developing new and better methods of analysis. We would strongly recoend that
new methods be presented in terms of the Ideal Xeth.od’ and that whenever pos-
sible. comparisons with real samples and incerlaboratory comparisons be made.
Flow injection analytical techniques are becoming very common. Continued
development should lead to th. automation of many col .oriaetric and f].uorometric
analytical methods for the measurement of free arid combined chlorine and its
various species in water. With the current emphasis on automation, the methods
that are to ba developed and those already developed can readily exceed present
standards of accuracy and precision. Automation will also lead to operator
independent methods and should lead to improvements in process control and
monitoring.
Chlorine Analytical 1(ethoda Comparative Studies.
The reader is cautioned against accepting the results of any or all of the
above tests without some reservations. Where possible we have tried to add corn-
30

-------
ments, parenthetically, based upon our knowledge of the field. It is very in.
portant in reviewing data from comparison tests that the analyst be aware of the
objectives of the comparison testing. For example, a test may be judged
unacceptable because of an unacceptable lower limit of detection that is beyond
the need for concern for other investigators.
In general when testing several test procedures it is important to identify
the objective of the testing. Equally important is the use of the data. In
reporting the results of the above tests, it should be kept in mind that many
manufacturers of chemicals for analytical methods and test Kits change their
procedures as a result of the testing. The concerned analyst needs to determine
if the results are still valid. This change is not necessarily applicable to
other studies where the chemistry of an analytical method is examined. In
general, the more the test studies chemistry and not merely the test procedures.
the more applicable the results are for future reference.
Another area of confusion concerns precision and accuracy. An analytical
method may be judged acceptable based on the precision of the results, while the
same method may give poor accuracy. These statistical parameters are separate
and must be tested using different exper3.mental designs. Comparisons with the
Idaal Method would require that both be at acceptable levels.
In general, there is a lack of comprehensive studies to better understand
the chemistry associated with the individual test procedures. Investigations of
this nature are necessary on a continuing basis, because of the advances in ana-
lytical instrumentation and our-continued improvements in understanding the de-
tails of the underlying chemistry.
Chlorine Dioxide Analytical. Method,s.
The todonetric method is a questionable method even for carefully controlled
research laboratory chlorine dioxide standards. In real samples where a large
number of potential interferences can exist, the method is destined to produce
erroneous results. Newer, more species specific methods are better choices.
Any method which determines concentrations by difference is potentially
inaccurate and subject to large accumulative errors- -beth in terms of accuracy
and precision. The subtraction of two large numbers to produce a small number
means that the errors associated with those large numbers are propagated to the
small number. The result in many cases is that the error is larger than the
smaller number, therefore, giving meaningless information. Methods such as
this, which obtain values by differences, should be avoided.
The DPD method uses the difference method in the evaluation of concen-
trations. The direct measurement of species by means of a more reliable and
accurate method to determine chlorine dioxide is needed. The same questions
raised about the DPD method for chlorine also apply here.
Ultraviolet spectrophoromecry, utilizing continuous flow automated methods,
has a great potential for accurate and precise measurements with the added
advantage of ease of operation and high sample throughput. Flow injection
analysis methods (FIA) should be carefully evaluated against existing methods
for accuracy and precision. The method should be field tested and the potential
31

-------
problem of membran. reliability should be evaluated for long term operations.
Additional bench studies using continuous flow methods with chemiluminescent
detection must be carried out. The superior selectivity of this method needs to
be utilized. Comparison lab testing and field study should be carried out.
Chlorite/Chlorate Ion Analytical Methods.
The Lodomecric/amperometric methods are indirect determinations of chlorite
ion and cannot be recommended. The DPD method for chlorite ion can not be
recommended because it is unreliable.
The iodometric sequential methods appear to be very workable on samples
containing greater than 1 mg/L chlorite ion or chlorate ion with good precisLon
and accuracy resulting. The method requires considerable operator skill and
experience to obtain good precision and accuracy for samples containing less
than 1. mg/I.. chlorite ion or chlorate ion. The method should be field tested
with other methods using both high and low ratios of chlorate ion to chlor .te
ion. The method should be used with caution on low level samples of drinking
water and/or wastewater, although direct methods requiring less specialized
skills are preferred.
Inrerlaboratory comparisons should be carried out for the modified
Lodomecr .c method for the direct analysis of thiorite ion and chlorate ion. The
detailed effects of various potential interferences need to be evaluated.
The argertcometric titration method is to be recommended only for relatively
high concentrations of oxy-chiorine species (10-100 mg/I..) but may be very useful
in establishing inter-laboratory bench mark comparisons at these high concen-
tration ranges. No such comparisons are currently available.
A highly precise, automated FIA method for low level chlorate ion needs to
be developed possibly using various masking agents such as glycine. oxalic acid.
malonic acid, and nitrite ion to initially remove other possible oxy halogen
interfering species. The method appears to be very promising in that it can be
used to directly determine low level chlorate ion concentrations.
Difficulties With Ozone Measurements: Need For Ideal Method.
As a consequence of the nature of ozone, its continuous self-decomposition,
volatility from solution, and the reaction of ozone and its decomposition
products with many organic and inorganic contaminants in water, the deter-
mination of dissolved residual ozone is very difficult. A detailed knowledge of
the mechanism of aqueous ozone decomposition and the potential role of the
various highly reactive intermediates, is imperative in order to accurately
evaluate th. analytical methods (15). In this context it should be noted that
most ozone methods are modifications of chlorine residual methods which
determine total oxidants in the solution. Therefore, ozone decomposition
products such as hydrogen peroxide and the like are also measured.
Iodomecry can be used as an example of the difficulties encountered in
making aqueous ozone measurements (16). Iodide ion is oxidized to iodine by
ozone in an unbuffered potassium iodide solution. The pH then is adjusted to 2
32

-------
with sulfuric acid and liberated iodine is titrated with sodium thiosulfare
to a starch end point. The ozone/iodine stoichiomecry for this reaction has been
found to range from 0.65 to 1.5. Factors affecting the stoichiometry include:
pM, buffer composition, buffer concentration, iodide ton concentration. sampling
techniques, and teaction time. The pH during the initial ozone/iodide ion
reaction and the pH during the iodine determination have been shown to markedly
alter the ozone/iodine stoichiertecry. The formation of iod.ate ion and hydroten
peroxide have been implicated speci.fically as factors affecting the ozone/iodine
stoichiomecry (Ii). Modifications in the iodine determination include changes
in end point detection, pH, and back-titration techniques. None of these
modifications has been demonstrated to be totally satisfactory.
The biggest difficulty in interpreting the existing ozone 1.iterature is that
no one method has been accepted as the Referee Method, Therefore, comparison
between several different methods can create false conclusions about the
accuracy of the methods. The method nest often used for comparative purposes in
the research laboratory is UV measurement of ozone at 260 nm. Even with this
method there is apparent confusion over the molar absorpcivicy for aqueous
ozone, with the values ranging from 2900 to 3600 K cm 1 (16).
All analytical methods reported, particularly those of early vintage, should
be reevaluated. considering the recent information about oxidative by-products
from ozone decomposition and the ozonacion process itself. Some of these
factors may not have been considered during development of the original
analytical procedures. Certainly, more detailed information and comparisons
should be available. Because of the difficulties of establishing a reliable
Referee Method we propose that the existing and future methods be compared
against an Nideal Methods. This IdeaL Method would incorporate all of the
characteristics that are desired for an ozone method, taking into account all.
other potential interferences, decomposition products, and samples originating
from various sources. Finally, automation, while nor an absolute necessity, can
add to the selectivity and ideal nature of a method for ozone determination.
Ozone Measurement: Ca. , Thase.
The many uses of ozonatton in the treatment of drinking water are controlled
by monitoring a number of parameters. Dissolved residual ozone La only one of
these parameters, and its measurement controls only disinfection conducted after
filtration, but before addition of a residual disinfectant for the distribution
system. However, it is very clear that the cost, efficiency, safety and
improvements in design of ozone water purification systems is extremely
dependent on the accurate determination of gas phase ozone. Therefore,
analytical methods must be developed that will, accurately measure ozone in the
gas phase and residual ozone in the aqueous phase. At this point it is
unrealistic to believe that one single method will, be acceptabl. for both sample
matrices.
todomecry, UV absorption and chemiluminescence are the thtee most common
methods employed for gas phase measurements (16). Each of these has been applied
to determine the amount of ozone present in generator exit gases, when stripped
from solution to the gas phase, or the amount of ozone in a contactor exhaust
gas.
33

-------
These techniques of monitoring concentrations in concactor exhaust gases are
quite promising as a method of controlling the production of adequate quantities
of ozone. This provides considerable savings in eLectrical energy costs for
ozone generation. Direct inter -comparisons of the various gas phase measurement
techniques are needed in order to evaluate accuracy.
Determination of stripped ozone in the gaseous state was reported in the
iLth Edition of Standard itethods (1.3) for measuring ozone dissolved in water.
However, in addition to the procedure being subject to the same limitations of
UV absorption and checiluminescence procedures in aqueous solution, the effects
of the gas stripping process itself must be taken into consideration.
Although the iodometric stripping/a ueous absorption method has been
approved in Standard Methods (13). we question the accuracy of the method. All
evidence would suggest that the method is problematic. Even though the
impurities are substantially left behind by the stripping, the actual procedure
and the continual decomposition of ozone does introduce inaccuracies into this
method. This method can be used as a relative measure of ozone for control
purposes.
This basic stripping approach followed by absorption in aqueous solution
(and colorimetric measurement) may deserve to be studied further. However, the
biggest potential problem appears to be that at high concentrations of ozone the
colorimetric compounds may react by a mechanism different from that used for
residual ozone measurements. Research should be concentrated on the reagents
that have already exhibited ozone selectivity.
todome try (Aqueous Phase).
If the performance of ozone in a spec .fic treatment application is not de-
pendent only on the ozone, but is instead a collective function of its reactLve
decomposLtion products as well, then iodometry can give a represerttatLve and
reproducible reading of the total oxidancs. For example, most European drinking
water treatment plants employing ozonatien as the primary disinfectant, have
relied on iodometr±c measurements as the basis for insuring adequate
disinfection, attaining a residual ozone level of 0.4 mg/ I.. in the first
contact chamber and maintaing this level for at least four minutes).
Kowever, it is now abundantly clear chat the 0.4 mg /I. value is a measure of
the amount of total oxidants present, and not necessarily ozone alone.
Therefore, either the absolute level of ozone required to attain the expected
degree of disinfection is lover than 0.6 mg/I. over the required period of time,
or tome of the decomposition/oxidation products formed upon ozonation also have
disinfecting properties, or both. Clearly, detailed experiments need to be
carried out to demonstrate the efficacy of disinfection by the decomposition
products of ezerm. Similar efficacy data for ozone decomposition products could
be developed for other uses of ozone (e.g., chemical. oxidation) when measurement
of residual ozon. levels must be made to control the process. Such data would
help to justify the continued use of jodametry to measure tetal oxidants,
rather than only ozone.
Historically. todoreetry has been used as the reference method for deter-
mining ozone, and against which other analytical procedures have been
34

-------
“standardized”. It is now quite clear that because of its lack of selectivity,
the use of iodomecry should be limited to that of only a control procedure. In
terms of ozonation processes, measurement-for control purposes-of the production
rate of ozone generators and bacterial disinfection/viral inactivation may be
based upon Lodomerry, provided the user recognizes the eany limitations of the
method. The reevaluation of this method must be carried out with the specific
goal being to define when the method is reliable and the situations where it i.s
not accurate.
Many authors have tactfully pointed out the many disadvantages of lodomecry,
leaving it to çhe reader to decide whether or not to use the procedure. In a
detailed comparison of eight analytical methods for the determination of
residual ozone it was concluded (16):
“No iodometric method is recommended for the determination
of ozone in aqueous solution because of the unreliability
of the method and because of the difficulty of the com-
parison of results obtained with minor modifications in
the iodometric method itself.”
Arsenic(tII) Direct Oxidation.
In the direct oxidation of arsenic(IIt). ozone reacts with inorganic
arsertic(III) at pH 4-7. the p14 is adjusted to 6.5-7 and the excess arsentc(III)
species is back-titrated with standard iodine to a starch end point. Values for
residual ozone determined by the arsenic direct oxidation method and by the
indigo method agreed within 6% of the UV values. The primary advantages of the
arsenic direct oxidation procedure are minimal interferences, good precision in
the hands of experienced operators, and apparently good overall accuracy. This
procedure continues to be recommended along with the indigo method. Additional
comparisons of this method should be made with the indigo method under various
conditions.
Syringalda.zine, FACTS.
The FACTS procedure, which was developed for the selective determination of
free available chlorine (hypochiorous acid + hypochiorice ion) in the presence
of combined chlorine (chloramines), has been adapted for the determination of
residual ozone (19). In this procedure, an aqueous solution of Ozone is added
to a solution of potassium iodide, and the liberated iodine is added to a 2-
propanol. solution of syringald.azine at pH 6.6. The resulting color is measured
spectrophotomecrical.ly at 530 nm.
The FACTS procedure has the major advantage of providing a spectrophoto.
metric procedure for the determination of ozone. However, the major limitations
of the FACTS method are still, those of the todometric procedure. Due to the
observed changes in slope and intercept which are problems caused by the
interferences, self .decouzposition of ozone, and seotettiometry, this method could
be reviewed in order to fully evaluate its potential usefulness. However,
considering the other colorietric methods that are available further
development of the FACTS method does not sees to give any promise of the
improved selectivity that is needed.
35

-------
N.N-Diethyl .p-phenylenedismiz , DPD.
The DPD procedure L a based on the ozone oxidation of iodide ion present in
.xcess phosphate buffer at pH 6.4 to produce iodine, which then oxLdizes the DPD
cation to a pink Wurster cation which is measured spectrophocomecrically, or
titrated. . The interferences include all oxidants capable of oxidizing iodide
ion to iodine, including ozone decomposition products, halogens, and nanganese
oxides (20).
One advantage of the DPD method is that determinations can be made by
ferrous ammoniua sulfate (FAS) titrimetry, specerophororeecrically or by a color
comparator. Ozone concentrations of less than or equal to 2 mg/I. can be
determined colorimetrically. Clearly, the procedure requires the difference of
differences and is limited by the same factors which limit iodoweery, specific-
ally the presence of materials which can oxidize iodide ion to iodine.
Although evaluation of this procedure versus the standard ultraviolet and
indigo procedures would seem to be necessary to make a more educated decision
about the continued use or abandonment of this method, the recommendation is
that other colorimetric methods are considerably more reliable then DPD.
Therefore development or testing is neither recommended nor considered necessary
at this time.
Indigo Triaulfoaate
The indigo method is subject to fever interferences than most colorinecr,.c
methods and fewer interferences than all iodomeeric procedures (21-23). At pH
2, chlorite, chlorate, and perchiorate ions, and hydrogen peroxide do not
decolorize Indigo Reagent when observed within a few hours and when the
concentrations of the intarferents are within a factor of 10 of that of the
ozone to be determined.
Ozone decomposition products and the products of ozonolysis of organic
soluces do not appear to interfere. However, chlorine, bromine, and iodine do
cause some interference, as do the oxidized forms of manganese. The addition of
malonic acid to the samples will mask the interference of chlorine.
For the Indigo Trisulfonate Method, it should be noted that when the
ultraviolet absorption method is used to standardize the indigo method (or any
method) for ozone, the choice of molar absorprivity is very critical. It is
recommended that the equations of Hoigne continue to be used since they are
based on a molar absorpttvicy of 2950 M’cm . If and when a different value
for molar abiorpeivicy is reported and confirmed, the (calibration) equations
would have to be appropriately changed. In this manner, all current
measurements using the indigo method would continua to be comparable.
The advantages of the indigo procedure is that it is based on a measure of
discoloration which is rapid and stoichtomerric. This analytical procedure is
recommended for use over any other procedure for the determination of residual.
ozone. Its primary attributes are its sensitivity, selectivity, accuracy,
precision, speed, and simplicity of operation.
36

-------
The gas diffu.siort flow injection analysis (CD-PtA) procedure eliminates the
interference of oxidized forms of manganese, and markedly reduces the interfer
ence of chlorine (24). Other than interference of chlorine which can be reduced
to zero by addition of malonic acid, there are no known interferences to the
determination of ozone by this CD-FIA procedure using the indigo method.
The primary advantages of the CD-PtA procedure are its accuracy.
selectivity. lack of interferences. reproducibility, and rapidity. Thus, the
method is wet], suited for laboratory research studies and for use as an
automated analytical procedure.
More studies should be conducted with specific gas-permeable membranes,
particularly with respect to repeated and/or continuous exposure to ozone solu-
tions. The use of hA equipment in a process control environment also must be
evaluated. The GD-PtA indigo procedure might well be adopted as the analytical
method of choice.
a-Tel idine
The o-tolidirte method (addition of 1-2 drops of o-tolidine solution to
ozone-containing water to develop the yellow color) is very simple, and easily
adapted to field color comparators, suitable for unskilled analysts. However.
this advantage cannot compensate for the lack of quantitation of the method, nor
for the carcinogenicity of the reagent (o-colidine). The recommendation is to
abandon this method.
Carmine Indigo.
The carmine indigo procedure has been used in Canadian water works plants
for the past 15 years. The ozone containing water is titrated with a solution
of carmine indigo until a faint blue color persists indicating that all of the
ozone has been destroyed. Specific interferences are unknown, but any oxidant
capable of decolorizing the carmine indigo dye most likely will interfere.
Effects of interferents should be determined, as should precision, accuracy,
and effects of reagent storage and pH. The method should be studied in direct
comparison with other methods, such as the iudigo and UV absorption methods.
Automation of this method could lead to improved selectivity for ozone.
Amperamecry.
With bare electrode anperometers, either the solution or the electrode is
rotated to establish a diffusion layer, and the electrical current measured is
directly proportional to the concentration of dissolved oxidant (25). Commer-
cial anpero .tric analyzers give satisfactory results provided there is no
oxidant other than ozone present in the sample. In many situations they provide
adequate monitoring of total oxidant. The bare electrode system has good
sensitivity, and is applicable as a contLnu us nonselective monitor for ozone.
When other oxidants such as chlorine, chlorine dioxide, bromine, and iodine are
present, the technique has difficulties. The exact nature and magnitude of
these interferences requires additional research.
37

-------
Due to the accumulation of surface impurities at the electrode surfaces, all
bare azsperomecric electrode systems are subject to loss of sensitivity with use.
With uncovered electrode surfaces, fouling has been observed to be a significant
problem as was the case in earlier tests with oxygen electrodes. Additionally.
the response is influenced by numerous surface-active agents and also halogens
and oxygen.
An improvement in the development of azperometric methods for ozone analysis
has been the application of gas-permeable membranes for increasing selectivity
and preventing electrode fouling (26.27). These Teflon nernbrane electrodes
exhibit less than 2% interference (in terms of current response) from bromine,
hypobromous acid, chlorine dioxide, hydrogen peroxide, nitrogen trichloride, and
hypochlorou.s acid (26.27).
This type of amperomecric membrane sensor needs to be developed further
based on the exhibited selectivities. The most disturbing attribute is the
temperature dependence. If different membranes could maintain selectivity vh .le
minimizing the temperature effect, this type of sensor could become highly
reco ended.
The application of positive voltage potentials and the use of polymeric mem-
branes that are selectively permeable to gases has enhanced the opportunity for
selective measurement of ozone. This is a very significant improvement aver
bare ..mperomecric elsctrod.s as well as most older colorimerric/spectrophoco.
metric and titrimetric methods. With an applied voltage of 1-0.6 V (vs SCE) at
the cathode, only the most -powerful oxidizing agents can overcome the
“resistance” of this anodic voltage and cause electron flow cathodically through
the electrochemical circuit. This general approach should conti.nue to be used
in future electrochemical developments.
Other Electrochealcal. Methods.
In the differential pulse polarography procedure (DPP). a predetermined
amount of phenylarsine oxide (PAO) is added in excess to an ozone solution to
reduce the levels of dissolved ozone present. Excess PAO then is measured
quantitatively by pulse polaregraphy. The DPP method may under some
circumstances be useful in the research laboratory. The prospects of its use in
the plant or field are not as promising since a higher degree of operator skill
is required. -
Potenriometry involves the cathodic reduction of dissolved ozone. The
diffusion-limiting current measured is proportional to the concentration of
ozone in the water. Further evalu.ation of potentiomecric systems may be in
order. However, the fundamental problems of electrode fouling must be
addressed. Fsrhaps a combination of membranes and porenciometric detection
would produce a promising system for ozone determinations. The system appears
to have modest potential for development.
Ultraviolet J(easureaents.
Ultraviolet absorption measurements also can be used far residual aqueous
ozone at 258-260 na. There is uncertainty with respect to the molar
absorptivity for aqueous ozone. In the literature, values ranging from 2900 to
38

-------
3600 M cm are reported. This uncertainty in the molar absorptivity is
critical to the future use and calibration uses of the UV methods. Clearly,
further work to ver .fy this vaI e is strongly recommended.
If the molar absorptiviry for ozone is known unambigiously, UV absorption is
in principle an absoLute method for the decermLnaci.on of ozone, which is not
dependent upon calibration or standardization against other analytical methods.
Therefore, it can be used for calibration of other analytical methods for ozone.
Et is specific to the determination of ozone, and is applicable to measurement
in gaseous and aqueous phases.
Physical Method.s.
The calorimetric method is based on the enthalpy of the catalyzed
decomposition of ozone ( H — 144.41 lU/mole). The calorimetric determ ,riation
of ozone is calibration-independent. The technique is specific to the
determination of molecular ozone, but is applicable to measurement only in the
gas phase. However, the higher the concentration of ozone in the gas phase, the
more accurate the method appears to be. since a greater temperature difference
is observed. Potential interferents have not been reported.
The method has been shown to agree with iodomecric and IJV absorption pro-
cedures, particularly for the measurement of ozone in the gases exiting ozone
generators. Therefore, the procedure can be used to monitor applied ozone
dosages. Additional detailed interlaboratory comparisons need to be carried
out.
The isothermal differential pressure procedure is based on the generation of
art increased nuaber of gas molecules during the UV destruction of ozone at
constant temperature. Then this reaction is carr .ed out isothermaLly Lfl a
closed vessel., the increase in pressure of the contained gas is proportional to
the ozone concentration. In prLnciple, this procedure achieves a totally
physical ozone measurement without requiring calibration using a chemical
method. Various automated instrumental. checks such as the stored molar
absorpciviry, the age of the UV light source, the zero point reading,
measurement of the flow of the test gas and the flushing gas, and the reading of
the diagnostic display are possible.
No specific comparisons are reported. However, in principle it appears that
this physical method is the best candidate for calibrating the gas phase ozone
instruments currently being used for ozonation control. As long as pure oxygen
is used for ozone generation this method would be free of interferences and
would be subject only to strict temperature control of the measurement cell.
Further study of this system would be necessary before it could be recommended
for further consideration.
General St.ary and Recommendations for Ozone.
In comparing all the methods to the ‘Ideal Method’ we find that none come
close to our ideal standard. Continued development of the various selective
methods will, however, come closer and closer to the ideal.
39

-------
In terms of gas phase measurements, none of the existing methods can be
reco ended for accurate determinations of ozone. If a relative value of the
ozone concentration is needed for control purposes. most of the methods repor:ed
could be applicable.
The accurate determination of ozone in the aqueous phase is complicated by
the decomposition of ozone, its reactivity to the ocher species present, and the
by-products of the ozonation reactions. Most current methods were ceveloped
without a clear knowledge of the associated ozone chemistry. Therefore most of
the methods are unacceptable or cannot be recommended. In particular, no
todometric based chemistry is acceptable for the determination of aqueous ozone.
Indigo trisulfonate and arsenic(III) direct oxidation are acceptable methods.
Amperometery continues to improve -• especially as an automated control method.
The stripping techniques have some merit in terms of improved ozone
selectivity. However, automated chemical systems such as flow injection
analysis offer considerably more promise. The current GD-F1A indigo procedure
is superior for residual ozone measurements due to its selectivity for ozone.
The moat important aspect of any potential new or improved ozone analytical
method will be speed of analysis and selectivity of the detection system for
only ozone. As a point of comparison, we strongly recoend that all future and
existing methods be compared against the ldea]. Method”.
LIT ATUR ,E
1. Symons, J.M.; eta] . “Ozone, Chlorine Dioxide and Chloramines as
Alternatives to Chlorine for Disinfection of Drinking water” in
Vater Chiorthatign: Env1ron nenrpl Irroact and Health Ef t s , 3 j.
2.. Jolley, R.L.; Corchev, H. and Hamilton, D.H., Jr., Editors, (Ann
Arbor, MI: Ann Arbor Science Publishers, Inc.. 1979) pp. 555-560
and Complete Report entitled “State of the Art ...“ (Cincinnati.
OH: U.S. EPA, November. 1977), 84 pp.
2. Proceedings of Seminar on “The Design and Operation of Drinking water
Facilities Using Ozone or Chlorine Dioxide”, Rice, R.C., Editor,
(Dedham, MA: New England Water Works Assoc., 1979).
3. MLll.r, C.W.; Rice, k.C.; Robson, C.M.; Scullin, R.L.; Kuhn, U. and
Wolf, H., An Assessment of Ozone and Chlorine Dioxide
Technologies for Treatment of Municipal Water Supplies”, U.S.
Environmental Protection Agency, EPA Project Report, EPA-600/2-
78/018. 1978, 571 pp.
4. Miltner, R..J. Measurement of Chlorine Dioxide and Related Products”,
in P1oceedfnj!s of the Uater ()t, pj [ y Techrtological Conference ,
(Denver, CO: American Water Works Assoc., 1976). pp. 141.
40

-------
5. Cordon, C. tmproved Methods of Analysis for Chlorate. Chlorite,
and Hypochiorite tons at the Sub .mg/L Level”, U.S. Environmental
Protection Agency, EPA Technical. Report. EPA-600/4-85/079, October,
1985. 35 p. and Presented at AWWA WQTC, in Proc. . 1JA Water Quali ’!
Technoloev Conference , December, Nashville. TN. 1982. pp. 1?5 l89.
6. Aieta, E.M.: Roberts, P.V. “Chlorine Dioxide Chemistry: Generation
and Residual. Analysis” in Chemistry in Uater Reuse , j. j,
Cooper, W.J., Editor (Ann Arbor, MI: Ann Aroor Science PubLishers,
Inc., 1981), pp. 429-452.
7. Hoigne. .3. Bader. H. “Bestimma.mg von Ozon und Chiordioxid in Wasser
mit dec Indigo-Methods” (“Decerminatton of Ozone and Chlori.ne
Dioxide in Water With the Indigo Method”), Vo Wasser. 1980, ,
261-280.
8. Gilbert, E.; Hoignd, .3. 9lessung von Ozon in Wasserverken; Vergleich
dec DPD- und Indigo-Methods” (“Ozone Measurement in Water Treatment
Plants: Comparison of the DPD and Indigo Methoris”), CFW-
Wasser/Abwasser, 1983, j. , 527-531.
9. Schalekamp, N. “European Alternatives and Experience” in Proceedinna
of the National (Canadjpn) Conference on Critical Issues in
Dririkinn ‘Jater Quality , (Ottawa, Ontario, Canada: Federae .on of
Associations on Canadian Environment, 1984). pp. 140-169.
10. Ikeda, Y.; tang, ‘I-F.; Cordon, C. lodometrjc Method of DeeermLnatjon
of Trace Chlorate Ion”, Anal. Chem, 1984, . , 71-73.
11. Emmenegger F.; Cordon, C. “The Rapid Interaction between Sodium
Chlorite and Dissolved Chlorine”, lnorg. Chem., 1967, . 633-635.
12. Ateta, E.M.; Berg, J.D. A Review of Chlorine Dioxide in Drinktng
Water Treatment”, .3. Am. Water Works Assoc., 1986, j , 62-72.
13. Standard Methods for The Examination of Vater arid Wastewaeer ,
Edition , Greenberg, A.E.; Trusseji, R.R,; Clesceri, L.S.; Franson.
M.A.H., Editors (Washington, D.C.: American Public Health Assoc.,
1985). 1268 pp. and Edition , Greenberg, A.E.; Connors, J.J.;
Jenkins, D.; Franson, M.A.H., Editors (Washington, DC: American
Public Health Assoc., 1980). 1134 pp.
14. Whittle, C.?.; Lapteff, A., Jr. “New Analytical Techniques for the
Study of Water Disinfection” in Chemistry of Water Suoolv
Treatment, and Distribution , Rubin, A.J.. Editor, (Ann Arbor, MI:
Mn Arbor Sci. Pub., Inc., 1974), pp. 63-88.
15. Tootyasu, H.; Fukutomt. H.; Cordon, C. ‘Kinetics and Mechanism of
Ozone Decomposition in Basic Aqueous Solution”, Inorg. Chem., 1985.
2 . 2962-2966.
41.

-------
16. Grunwell, J.; Benga, J.; Cohen, H., Cordon. C. “A Detailed Comparison
of Analytical Methods for Residual Ozone Measuremenc , Ozone Sci.
Eng. , 1983. , 203-223.
17. Fiamm, D.L.; Anderson, S.A. “todate Formation and Decomposit: n in
todomecric Analysis of Ozone’, Environ. Sci. Technol.. 1975.
660-663.
18. Rehize, K.A.; Puzak. .J.C.; Beard, M.E .,; Smith, C.F.; Paur, R.J.
“Evaluation of Ozone Calibration Procedures”, U.S. Environmental
Protection Agency, EPA Project Summary, EPA.600/S4-80-050,
February, 1980, 277 pp.
19. Liebermann, J., Jr.; Roscher, N.M.; Meter, E.P.; Cooper. tJ.J. Develop-
aenc of the FACTS Procedure for Combined Forms of Chlorine and
Ozone in Aqueous Solutions”, Environ. Set. Technol., 1980, j ,
1395-l(.O0.
20. Palm, A.T.; Derreumaux, A. “Determination de lOzone Rdsiduel dans
l’eau” (Determ3 .nation of Ozone Residual in Water”), L. Eau et
l ’.Indu.strie, 1977, ] , , 57-60.
21. Bader, H.; Hoigne, J. “Colorimecric Method for the Measurement
of Aqueous Ozone Based on the Decolorization of Indigo
Derivatives”, in Ozonizatiori Manual for ‘Jacer and Jaste’.7ater
Treatnent , Masechelein, W,J., Editor, (New York, NY: John
Wiley & Sons, 1982), pp. 169-172.
22. Bader. H.: Hoignd, J. “Determination of Ozone in Water by the
Indigo Method”, Water Research 1981, j, , 449-456.
23. Bader, H.; Hoigné, J. “Determination of Ozone in Water by the tndigo
Method; A Submitted Standard Method”, Ozene Science and Eng.,
1982. . , 169-176.
24. Straka, M.R.; Cordon, C.; Pacey, G.E. “Residual Aqueous Ozone Deter-
ination by Cas Diffusion flow Injection Analysis”, Anal. Chem.,
1985, .Z . 1799-1803.
25. ltasschelein , W.J. “Continuous Aznperometrtc Residual Ozone Analysts
in the Tailfer (Brussels, Belgium) Plant”, in Ozonization Manual
for Wptet and Vastewater Treatment , Masseheleirt, U., Editor, (New
York, NY: John Wiley & Sons. 1982), pp. 187-188.
26. Stanley, J.H.; Johnson, J.D. Amperometric Membrane Electrode for
Measurement of Ozone in Water”, Anal. Chem., 1979, . I. 2144 ’2141.
27. Stanley, J.U. : Johnson, J.D. Analysis of Ozone in Aqueous Solution”.
in Handbook of Ozone Technology and Applications , 1. Rice,
R,G. and Netzer, A.. Editors (Arm Arbor, MI: Ann Arbor Sci. Pub..
Inc., 1982), pp. 255-276.

-------
A GOIDE FOR EFflClD f USE OF ThIS REPORT (AND A BRIEF GLOSSARY OF TEF .flS)
This Report contains a very detailed review of all disinfectant residual
measurement methods. The Executive Sunmary is intended to give readers a brief
overview of the advantages arid disadvantages of each method. To that end, Table
I (Charactaristics and Comparisons of Analytical i’(ethods) has been included - to
summarize each of our findings and to recommend posaLbie directions for future
research. In addition. Table II (Equivalent Weights for Calculatthg
Concentrations on the basis of Mass) descrLbes the equivalent uetghts of each of
the disinfection spec .es in terms of the actual reactions involved in the
disinfection process.
Each chapter contains individual. recosendations following the discussion of
the method. A summary of all of the recommendations is also given at the end of
each chapter. Additional help is given by means of an alphabetical Index
containing more than 2500 individual terms. Specific cross referencing for all
recommendations can be found in the Index either under the recommendation” • or,
in terms of the subject of the numbered recosendation itself.
The term Referee Method is used to describe appropriate comparisons with
existing methods and Standard cthods refers to a £pecifically recommended
method. The Index should be an additional aid to finding the data .ls of
specific methods.
In this context, it should be noted that the individual literature citations
are specifit to each individual chapter - and are either numbered individual],v
within chapters 2 and 3, or alphabetically sequenced within chapters 6 and 5.
Chapter 4 (Indexed Reference Citations) has been included in this report n
order to assist readers in locating particular papers of interest. The 68
categories for chlorine, chloramines, and the oxy-chlorine species, along with
the additions]. 60 categories for ozone, should make the task of finding in
dividual papers of interest considerably less cumbersome. Papers which describe
several methods have been included in each of the appropriate categories. Al].
together, the 1.400 references cited in Chapters 1-3 number more than 2,000
individual citations vh.n distributed in the indexed form of Chapter 4.
Chapter 5 is an alphabetical listing of the individual references citations.
Finally, a detailed Index has been included in order to assist readers in
locating subjects of specific interest. 1.7. hope the readers will find these
additional chapters as useful as have we in preparing this report.
A brief Glossary follows on the next page in order to assist readers in the
various specialized terms and abbreviations used in this report. For additional
terms, the reader is referred to the Index.
43

-------
CT.GS SARI
Accuracy - . the ability to determine the correct concentration
BAXI - boric acid buffered potassium iodide method for ozone
Breakpoint the inorganic reaction of chlorine with ammonia nitrogen
CDflJ - . chlorine demand free water
Combined Chlorine -• inorganic and organic chloramxnes
Detection Limit - - a signal that is 3 times the noise level of the system
DCC - - dissolved organic carbon
DPD - - (N ,N-diethyl-p-phenylenedianine)
FACTS - . free available chlorine test with syringaldazine
F M - - flow injection analysis, an automated analysis procedure
Free Chlorine - - the species, C l 3 + MCCI + OCl
KI -• potassium iodide method for ozone
LCV •- leuco crystal violet
m l . -- milliliter(s), standard unit of volume
Molar Absorptivity (c) reported in units of wtcm t
NBKI - - neutral buffered potassium iodide method for ozone
Precision - - how well the method reproducibly measures the same
concentration
Reactive Intermediate -- species such as 02, H0 3 , HO 3 , OH, 03, etc.
Referee Method - - the method aqainat which a working method is compared
Sensitivity -- the change in signal per unit concentration (i.e. Amps/mol]
Standard Methods - - the book, Standard Methods for the Exaninstion of
Water and Wastewater published by APHA, AWWA, and WPCF
trihalomethanes
Total Chlorine - . the combination of Free Chlorine and Combined Chlorine
TOC . . total organic carbon
TOX -. total organic halogen
44

-------
APPENDIX E
INACTIVATIONS ACHIEVED
BY VARIOUS DISINFECTANTS

-------
VALIES I IflCtIV*t 121
:r 0141014 0 1571 11 P 1 23 CNL l 1(
aT 3 5 C U
.09 InSCtIvStlfl .09 trattrn;1vs .,q InscIuwaI&us
::wCENrl It : .
5 3 s 2.3 2 3 3.3 :.s 3 2.0 2.3 3.3 :5 : : : : ! 3
“ 0 :3 .6 : •14 :37 27 54 52 ‘39 134 63 33 :5 t5 3 53 5
. 7 a I_ I 25 ¶6 s :12 143 66 33 33 :7 ::a
:5 :..5 7q 1’_5 29 57 56 15 143 72 5 :8 ;3 37 -“ ::s
a :9:23 as 29 59 53 117 1 47 76 35 :5 • 0 ‘5 V3
2 •5 ‘6 ‘71 27 ‘32 33 60 ; 123 153 53 36 ‘2 t3 .5 ‘‘1
- : ¶2 ‘3 :33 :ao 155 31 61 ; 123 153 ‘64 37 t’1 •7 14 UI
9 Q5 ‘31 137 32 63 95 176 154 109 35 ‘3 fl3 “1 45 226
3 27 ¶4 I I ‘03 135 162 32 64 97 179 6 I 193 39 77 ‘ ‘6 ‘36 ‘ Il 231
2 23 ¶5 53 110 133 165 33 64 991351 6 5197 39 Ye ‘17 1 236
2.2 26 ¶6 35 ‘I I 161 169 34 67 101 134 ‘66 201 40 31 •fl 61 32 262
2.4 29 51 56 115 143 172 .34 dl ¶03 : 17 r71 205 n 32 124 165 2:6 1’?
2.6 29 53 6.3 I I ? 46 ¶7 3 35 73 103 139 176 209 ‘2 34 126 66 112 252
2.6 30 59 59 1 )9 148 ‘Vs 36 71 ¶07 142 ¶7 3 2.13 43 53 129 171 2 76 257
3 30 60 i Ifl 51 l51 36 72 109 14$ 16? 217 ‘4 57 ‘31 174 216 28?
,as ?.S pu40
(aQJL)
3 3
1.3
1.5
2.0
2.5
3.0
0.5
1.0
1.5
2.0
2.5
1.3
3.3
1.0
1 5
2.0
2.5
3.0
0.4
40
79
119
153
195
237
44
92
139
153
231
277
55
110
163
219
27
379
0.6
‘0
50
120
159
199
49
44
95
143
191
235
2*4
57
1 )4
171
223
263
342
0.6
61
52
123
164
209
246
49
95
145
¶97
246
295
59
113
177
236
295
354
1
‘2
64
127
169
211
233
5?
101
152
205
233
106
61
122
153
243
306
365
1.2
43
66
130
173
216
259
52
1%
137
ZX
261
113
43
133
136
231
3 )3
324
1,6
44
69
133
177
222
256
54
107
161
216
264
521
65
¶29
194
256
323
38?
1.6
46
9?
I I?
1U
U I
273
55
110
163
219
214
329
66
132
199
263
331
397
13
47
93
16*
156
2.23
279
54
II ,
Ifl
Z23
333
65
134
204
271
339
40?
2
65
95
141
¶91
23*
236
56
115
173
231
2&
346
70
139
209
273
344
617
2.2
50
99
‘49
199
246
297
39
113
17?
396
353
71
142
213
234
M I
‘26
1.4
30
99
¶69
¶99
246
296
60
120
¶31
241
301
361
13
165
215
290
363
‘35
7.6
5 1
101
152
233
233
304
61
123
I$4
245
347
346
74
¶ 46
222
296
370
4.4
3.8
52
103
153
20?
UI
310
63
121
135
210
313
373
75
151
226
301
377
‘52
3
53
195
¶55
21%
243
114
44
127
191
215
315
312
77
153
2.33
357
323
460
tkl. 1US
ca 1un
(99643
O.4 63 IS 199 140 UP 199
0.6 45 134 206 211 33) 447
0.5 70 041 211 141 352 ‘22
1 75 ¶44 219 291 3M 437
1.2 75 IS O 226 301 374 451
1.4 77 133 232 109 Sn 444
1.6 50 159 239 314 199 477
1.5 *2 163 243 314 ‘50 499
2 53 1 67 210 UP 41? 535
2.2 65 173 356 541 424 51%
2.6 57 174 24* 345 433 522
2.6 99 17* 267 333 444 533-
2.3 91 151 212 362 ‘33 54.3
3 92 164 216 364 660 532
C L lI 1 LSQ IflSCtlVIIIfl 499 iflsttinrin 7.09 lnactin;,sn
499 Lmt* un
0.3 1.4 1.3 ZJ 2.3 3.0
us a , CT • CT ts r 3•Lq •PUn?99r’
‘9.,

-------
‘4$63 5-2
VALLII I INACtIVAt ION
:F Clajola CYSts I? 7 563 CNL IuI
£1 S C
9 1 1 .6.5
:1.7 3
.a9 Irl$ct van , Log In.cIIv.t1 _:q
3 I 3 15 2.3 2.5 3 3 3.5 1.3 1.5 2.0 2.3 3.0 5 3 5 3 5 3
.2 . 6 32 .7 63 51 97
16 7 33 53 7 Si ‘CO
. 5 31. 52 9 36 ‘35
S 35 53 3 36 105
2 5 !6 54 ‘1 39 ‘37
• . 3 35 ‘3 • 3 01 ‘39
5 9 37 03 I I I
‘3 9 33 37 r o
2 9 39 58 7? 97 116
2.2 20 39 59 70 93 ¶18
2 1. 20 3 60 30 *00 123
26 20 ‘1 61 31 102 ‘22
2.5 21 t 62 83 103 •12&
$ 1 .2 63 51. 135 ‘26
20 39 59 78 06 117
20 —O 60 80 100 123
20 4 61 61 132 132
21 ‘2 63 33 104 123
21 .2 4 65 186 *2?
22 43 65 67 106 ‘30
22 .4 66 38 110 132
23 ‘3 68 90 113 135
32 .4 69 92 113 138
2.3 1.? 70 93 11? *1.0
2’. 44 72 93 119 *1.3
24 49 77 97 127 *1.6
25 ‘9 74 99 123 *43
25 50 76 101 126
23 .6 ‘3 3 “6 57
21. .8 2 ;s ,
21. .7 ‘-3 ; 22 -6
‘S 53 :9 •34 9
25 5 165 1 ’37 ’53
26 52 ‘6 ‘03 ‘29 ¶55
26 ¶3 “9 •33 ‘32 ‘56
27 54 61 ‘38 35 62
28 55 •3 ‘ 0 38 .63
28 56 33 113 ‘1.1 169
29 5? 36 115 11.3 173
29 55 58 ‘17 ‘1.6 175
30 59 39 9 1 $ *73
30 61 1 ‘21 12 ‘62
9.! .? 3 _.0
:51.00 :55 LOg Ifl tivst .O1 1.01 iuc8tvS5* . Log ANC1.,v*t*
2*C5IITR 1 1TION
( “ 511.) 3.5 1.0 5.5 2.0 L5 3.0 3.5 1.3 53 2.0 2.3 3.0 0.5 1.0 1.5 2.3 2.3 3.0
‘ .0.
0.6
0.3
1.2
1 4
1.6
15
2
2.2
2.4
2.6
2-s
3
2! 55 53 111 138 *64
29 31 ’ 66 111. 143 171
29 36 83 ¶1? 11.6 115
30 60 90 119 149 ¶79
31 6* 97 122 ¶53 163
31 67 94 123 ¶56 1$?
32 U 96 ‘23 160 197
33 63 98 *31 *63 *96
33 6? 100 133 167 200
34 68 102 136 170 204
OS 73 108 *39 174 290
36 71 10? 14.3 170 213
34 72 109 143 181 217
37 74 111 147 186 221
33 34 99 132 165 *91
34 68 102 *36 170 304
55 70 105 *40 1?! 2*8
34 72 101 144 180 216
3? 7 ’ . 151 147 186 221
11 76 114 151 109 227
39 77 *16 153 193 232
40 79 119 159 191 231
4.1 5* 122 162 243
41 63 124 108 237 240
‘2 86 *21 169 211 233
‘3 66 129 172 2*3 231
44 09 137 ¶7 1 219 343
45 69 134 179 3M
39 79 118 ¶5 ? 19? 236
4* 61 132 163 203 21.4
62 64 *26 68 210 232
41 3? 130 173 217 260
4% I I 136 113 223 267
44 9* 13? 163 221 274
47 94 U I 181 234 281
4 96 144 191 239 21?
49 93 11.7 196 21.5 2%
53 100 ¶30 230 250 300
51 ¶02 133 2% 233 306
52 134 153 206 260 3*2
53 *06 139 212 263 31$
53 186 562 2*6 270 324
3 5 )90*86
180
409
4343 0.5 1.5 1.1 LO 1.3 3.0
0.6
0.3
1.2
1.4
1.6
2
2.2
3.’
2.6
2.3
3
47 95 139 109 371
‘9 91 364 *96 363 291
53 190 971 201 231 201
33 101 186 3M 312
53 107 300 212 217
53 113 *0 319 213 379
54 1*2 309 lii U?
51 US 172 730 3M US
S I 11$ 177 3M 3M 3M
60 120 I I I 2(1 331 341
II 121 *86 243 301 364
43 123 09 200 113 271
64 *21 191 212 3M
45 130 195 209 231 3M
P$ CT • CT Isi 1 ’ -197 tnNft 1siI
0.*

-------
;aIIao
A S iA 1 -3
vaugs $0’ INAC I IVAT SCN
2 Cxaots C 51S ir r.u
AT 10 C
:‘n? 3
ag 1nsct vnioni . 09 lnscltwsnovi$ . q Inictu .attaj
:iiCEs ltAti :u .
‘i / Li 35 • 3 ‘.5 2.3 2.5 3.3 3 5 0 • 5 2.0 2.5 3.3 5 3 5 2 3 2 5 3 3
2 4. 37 .9 51
3 25 28 50 s3 I
1 26 39 32 sS 8
‘1 26 .3 53 so
1 27 .3 53 5 ? !0
4 27 .1 ¶5 58 52
‘ 25 ‘2 55 # 53
. 4 9 .3 57 72 36
‘5 29 .1. 55 73 57
5 33 .5 59 74 59
13 33 4 60 75 90
15 51 . 5 61 7? 92
16 31 7 62 75 93
6 32 ‘3 63 79 95
C 4L0’Ifl 409 ItIaCtIvStisfl

( /L ) 3.5 1.0 1.3 2.0 2.5 3.0
‘3 29 .4 5 9 ‘ 35 11 25 ¶2 9 !7 :4
•5 3 .5 3 93 •$ 36 *4 - ‘ *9 . 7
*3 31 .6 sI fl 92 5 27 ¶5 1 12 ‘0
6 31 .? 63 18 94 19 37 ¶6 73 73 :2
16 32 .3 63 79 95 19 25 ¶7 ‘6 fl .4
•6 33 9 65 82 98 19 2 ¶5 ‘7 97
1? 33 50 66 83 99 20 ‘0 60 79 79 19
¶7 34 51 67 54 *01 20 . 1 51 51 132 ‘22
1? 35 52 69 37 104 21 41 2 53 133 24
18 35 ¶5 70 58 105 21 ‘2 s IS • •
15 34 54 7 1 59 lOT 22 ‘3 53 55 33 •79
18 37 55 73 92 110 22 4 4 56 87 109 11
19 31 56 74 93 I I ! 22 ‘5 6? 59 112 134
¶9 38 5? 75 94 113 22 6 59 I I 114 •37
0.6
0.8
1.2
1. 4
1.6
‘.3
2
2.2
2.
2.8
2.8
3
21 ‘2 65 53 104 *75
21 43 64 55 107 128
22 44 66 87 ¶09 ¶31
22 ‘5 6? 59 112 154
75 41 69 9* 1*4 137
23 ‘7 70 93 117 144
24 ‘4 72 96 120 144
25 ‘9 74 98 123 147
23 50 75 ix 123 no
28 SI 77 102 124 133
26 52 79 105 131 151
27 53 30 107 133 ¶ 60
2? 34 u *08 154 163
23 55 33 111 ¶33 1 6
25 50 75 09 126 141 3D
2.6 51 77 *02 123 135 31
24 53 79 105 ¶32 153 32
27 54 81 103 ¶35 162 55
2$ 55 53 111 133 966 33
23 37 23 *13 ¶42 170 54
29 54 37 ii i US *74 35
30 60 90 ¶19 ¶49 179 3$
30 6* 91 121 132 153 31
31 42 93 126 153 131 34
32 63 95121*53190 33
32 65 97 129 *62 ¶9 1 39
U 6 6 99 131 *66 197 40
34 67 101 134 153 205 41
59 59 113 t&3 171
61 92 122 153 133
6.3 9 126 155 159
65 95 130 183 195
6? 100 133 16? 200
69 103 137 172 201
70 106 141 178 211
72 151 ¶43 179 215
74 111 1$? 134 221
75 113 150 ‘a za
77 1*5 153 199 230
73 117 *56 195 234
30 120 139 ¶99 239
31 tU 162 208 24.3
CkL0’Il4
0s 4IMnI In
C lL3 0.3 1.0 5.1 2.0 LI 3.0
‘ .4.4
0.6
0.S
t.2
1.4
7.6
1.3
2
2.2
2.6
2.6
2.3
3
35 70 ¶01 119 1%
56 73 *08 145 Ic U s
it i i i is Ut
59 74 1 17 156 195 536
40 40 120 160 200 tea
41 53 124 16$ 206 247
42 34 127 169 211 253
N ill 173 216 59
44 40 133 177 221 236
45 90 13$ 131 221 271
44 92 533 134 230 27$
47 94 $41 IS? 254 24 1
4$ 96 *44 191 239 U ?
49 91 144 195 243 292
‘ .13 .
38
2
16
IS
2
2.2
24
26
25
409 IViictivsrifl Log InsCtlvtti a
0.3 ‘.0 1.5 2.0 2.5 3.0 0.5 I . ) 1.5 2.3 2.5 3.0
at.O
usni C? • C l fw 3’t Is tInt*r
08.9

-------
F GIJJOLI. CYSTS IT P Itt C%n .08 111
“ is C
,•7 0
. _ . . . If .acta et
‘9!Ll .5 1.0 ‘ S 2.3 25 53 .5 3 S 2.3 2.5 30 5 23 23 33
‘3 I .3 •3 23 33 39 .9 ¶9 ‘2 Z3 :s .7 s -
3 7 5 33 - ¶3 3 23 33 .3 ¶3 so ‘7 :. 6 .1 3 -z
• 3 1 7 33 35 3 •3 23 31 41 51 61 ‘z :. , .; i .3
‘5 2? 53 -. 53 II 21 32 .2 53 63 13 :s ss .s 5
2 8 2? !6 • . n 21 37 .3 53 4 ‘3 25 :3 sI 3 •6
3 23 3 -6 5 I I cZ 33 43 51 S ‘5 59 12 bS
• 3 23 37 .7 56 II 22 33 .6 35 66 ‘3 :s 3 66
3 3 9 29 18 —6 ¶7 11 23 3!. 43 57 68 ‘4 27 -. ¶4 sI 31
2 3 19 29 39 .8 38 12 73 35 ‘6 58 69 14 23 -Z ¶5 ,9 ¶3
2.2 ‘3 20 30 39 49 59 12 23 35 ‘.7 58 70 ‘4 23 .3 3? ‘I 55
‘ •3 20 30 .0 50 sO 12 2’. 36 8 60 72 I’. 29 .3 ¶7 72 5.6
2.6 3 20 31 —I II I 12 2’. 37 ‘9 61 73 IS 29 .. 50 73 36
2.8 3 21 31 .1 ¶2 62 12 23 37 49 62 74 s 30 .5 59 7’ 39
3 ‘1 21 32 .2 53 35 13 25 33 51 63 76 IS 39 —6 33 76 91
.3
.09 1cTtvatIw ’ .09 If % W$I1 1.09 IrJCYIVItIW
1 C M
hP 3 S 1.0 ¶ S 2.0 2.5 3.0 0.5 LO 1.5 2.0 2.5 3.0 0.5 hO I 5 2.0 2.3 3.0
39 59 79 9* 118
3.6 41 3% 81 102 ¶22
3.8 ‘2 53 84 105 ‘04
3 65 87 104 ¶50
1.2 45 37 89 112 134
1.4 44 69 9* 114 131
1.6 47 7* 96 114 145
1.5 41 72 94 123 U4
2 49 74 05 123 l IT
2.2 30 75 100 13 ¶30
2.!. 51 7 ’? 102 175 135
2.4 52 70 136 130 134
2.6 53 33 ¶06 733 159
34 87 lOS 133 162
LOS (. t vs*fws
U11tMI00
(0511.) 0.1 0.3 1.3 2.0 2.5 3.0
23 47 7* 93 117 740
0.6 24 49 15 9? 123 846
0.3 23 50 16 101 126 I I I
I 26 12 1* 101 133 114
1.2 27 53 *0 10? 13 160
1.4 2* 53 110 133 063
¶4 23 36 08 ¶13 141 169
1.1 29 54 SI 115 144 175
2 30 19 19 11* ¶46 ITT
2.2 30 60 91 121 151 13?
2. 1. 31 60 92 123 in i08
2.6 3? 63 94 123 157 *03
2.8 32 64 96 127 159 19*
3 3363 05130163 195
14 28 ‘2 53 69 83 17 33 50 64 83 99 20
14 7 43 i 36 17 34 51 61 83102 70
IS 29 41. 39 73 88 18 33 53 70 $3101 27
15 30 ‘.5 60 73 90 15 36 54 72 90 103 22
13 31 ‘6 81 77 92 19 3 ? 56 74 93 ¶11 22
76 31 ‘.7 63 73 94 19 35 57 74 II 014 23
16 32 1.4 64 60 96 19 3? 33 77 97114 21
13 33 49 35 82 95 20 44 60 79 99119 24
17 33 50 37 83 ¶00 10 4% 6* 1* 102 133 23
1? 34 51 64 85 102 II 41 63 83 103 *24 23
1 35 13 70 04 103 21 41 04 23 106 127 26
18 36 54 71 39 107 22 43 33 08 103 139 26
15 36 53 73 91109 22 *0113*33 2?
19 31 56 T 93 ¶11 22 ‘S 67 84 113 731. 27
.0
0016% CT • CT 4w 1 - 7 0 5 PT$’S**S
0.9

-------
:, GIAlOSA CYSIS IT $ 15 1 CWL 5L6I
g C
1? 3
.39 Ct a s .09 l,ilctivs ,w .39 IrOCtP.$TtonI
.C2I 15aflCa.
•5 •3 5 3 25 3 5 3 55 20 25 3.0 5 3 •5 3 25 32
‘2 a :. o :s 7 5 22 9 37 4 9 .7 5 :5 5 2
:6 , 3 9 .3 2 3 5 ‘5 23 32 5 .5 3 3 27 5 .s
2 3 3 ; 25 33 1 S 55 2.3 35 33 .6 Q ‘3 5 17 .6 15
3 3 25 33 51 S :s 24 31 39 7 9 3 25 37 .7 “ .
‘2 3 3 2.7 33 . S 6 24 32 .o .3 •0 I 39 33 .3 57
25 27 34 .1 S 6 25 33 .1 9 19 9 9 5
• 3% 33 33 . 3 17 25 33 10 2.0 33 1 • 3
3 ‘4 22 29 15 .3 9 :7 23 34 3 31 10 20 31 .5 51 o
2 7 ‘5 22 29 57 . 9 5? 26 35 43 sz 10 21 51 .5 12 52
2.2 7 ‘ S 22 29 37 . 9 53 27 55 33 si 21 32 .2 53 sS
2 3 13 23 30 35 .5 9 13 27 36 3 5 si 22 33 .1 14 s
7.6 5 .5 23 31 35 ..o 9 13 73 57 53 ii 22 53 — . IS so
2 5 3 ‘6 24 31 39 .7 9 ¶9 23 37 47 56 I I 22 34 .5 36 sl
3 8 s 2 31 39 .7 0 ¶0 29 58 a 57 s1 23 34 .3 i?
3,,.? S
109 Lrhc1 utIol LOS 5IIOCt%v4t 409 SftSCI1,Ot,OflI
: 6C( lTIaTZ06
(e9/4) 3.5 I 3 1.5 2.0 2.5 3.0 3.5 5.0 1.3 2.0 2.5 8.0 0.3 1 9 1 3 2.0 2.5 3.9
..0.6 ‘0 21 SI 4) 52 52 12 25 37 49 43 74 13 30 43 39 1$. 39
0.4 1% 21 32 3 53 64 53 26 39 SI 44 77 13 31 46 65 77 92
0.5 I I 22 33 ‘4 53 56 13 23 ‘3 53 56 79 16 32 ‘6 s3 79 93
I iS 22 36 ‘3 36 6? 16 27 ‘I 34 63 81 16 33 4 63 33 95
5.2 12 23 35 ‘6 55 69 14 38 42 35 69 53 17 33 30 6733100
1.4 12 23 35 ‘.7 55 70 14 38 63 5771 53 17 34 32 69 56103
1.6 ‘2 24 36 43 60 72 15 39 u 53 7j 57 15 35 53 7088105
5.5 12 25 37 49 63 74 13 33 5 597439 55 33 54 72 98104
2 13 21 38 50 63 73 13 30 (4 61 76 91 58 37 53 73 92 110
2.2 13 26 39 ¶1 64 77 16 31 4762 13 93 19 333775 96513
2.’. 13 26 39 52 65 75 16 33 4163 7995 tO 3.6 35 77 96513
2.6 13 2744 33 67 53 14 33 4961 II 97 20 39 39 75 00157
2.3 14 2761 54 61 51 17 33 305683 00 20 4350 7939119
3 1$. 23 42 31 60 53 11 34 31 37 34 105 20 45 61 51 592 133
C1t lSl LOq t C*f SI1
c09 5fIAT 509
(. i ) 0.5 1.0 1.1 LO 2.3 5.0
d .3,4 iS 33 U 70 U 105
0.6 18 36 05 75 91 109
0.1 19 36 57 75 56 113
1 20 39 30 73 99 117
1.2 20 40 60 09 100 120
1.4 21 1 12 103 133
5.6 21 ‘2 83 56 103 12*
1.3 22 45 65 16 101 129
2 33 44 46 01 150 133
2.2 33 65 I I 98 I I) 133
2.4 33 44 *9 92 115 136
2.6 24 47 TI 56 13* 145
2.3 24 41 12 95 119 543 c i • cy e,r S.O.S 5l I ti.l
3 26 49 73 97 133 544 98.9

-------
:c .1D1A Cflfl S T V hS C*Latfl
1 25 C
.09 nntiw.c ’w . o nactIYhtIwn -fl inierrv.uons
::NCL STS .
‘c 33 ‘0 1.5 2.3 2.5 33 3.5 3 1.3 2.0 23 3.0 :5 .3 ! l :s i
;JI•’ 5 9 . 1 . 6.0 4.5
L09 Znactsv*t.n 409 &nStlhntin Loq 1nactIvot.a
czw 1fl I cow
509 14) 3.5 *0 1.5 2.0 2.5 3.0 0.5 1.0 1.5 2. 0 2.5 3.0 04 1.0 1.5 2.0 2.3 3.0
0.6
0.8
12
1.4
1.6
1.8
2
2.2
2.4
2.6
2.8
$
caa.rui is
0 *09.0
Is I tiflt*a
CM /U 0.3 i i 1.3 2.0 2.3 3.0
0.4
0.3
1.2
1.4
1.4
04
2
2 . 2
2.8
2 4
2.3
3
12 0 5 4? is m
12 24 37 49 61 73
is a M 50 43 75
13 U 39 52 40 73
03 27 40 33 47 n
to 27 41 13 a U
n a ta so is so
14 fl 43 3? 72 U
15 29 44 59 73 U
15 30 43 40 75 90
15 31 44 61 7? 92
*4 31 47 63 75 94
16 32 44 46 90 94
16 32 49 63 I I 9?
‘ ‘s -
.
8
12
s
:3
5
1 1
9
24
29
*
2
3
:s
21
:s
.
.
8
1
7
21
23
3
3 •3
20
25
30
6
1
3
.
I
:s
:
•
t
I
“
22
26
5
1 16
2 0
26
31
2
;
:5
31
37
3
•3
7
22
:6
5
• ‘6
2 3
16
31
8
1
o
:s
31
3?
;
1
3
23
2?
3
‘ I 16
21
27
32
o
I
I
25
32
38
.
5
4
4
1
23
2?
6
I I 07
2 2
28
33
7
1
:
:s
i i
09
b
4
•.
1
23
28
6
11 I?
22
28
33
7
1
23
2?
33
.0
5
S
‘0
‘ S
‘1
24
29
6
II 17
23
a
7
1
21
2?
3.
a
2
1
10
13
3
24
29
4
‘2 I I
23
29
33
1
•4
21
27
04
45
2.2
5
0
53
20
23
30
6
12.14
23
29
33
7
21
21
33
‘2
2’
3
10
13
2*
25
30
6
12 16
24
30
36
7
1 ’
22
29
36
.3
26
5
10
16
21
26
3)
6
12 59
23
31
57
7
15
22
29
1?
‘4
2.8
1
IQ
16
21
26
31
6
52 19
23
31
37
4
¶3
3
30
38
‘5
3
5
11
36
21
27
32
6
13 19
23
32
38
8
1
23
01
38
-6
7
14
21
28
33
42
8
5?
23
33
q
3 5
13
20
30
39
49
59
7
14
22
29
36
•3
9
1?
25
34
3
31
50
20
31
‘1
50
61
t
is
zz
29
37
‘4
9
18
27
33
‘4
33
I I
20
32
‘2
13
63
a
is
23
30
38
‘5
9
18
27
36
43
34
11
22
33
‘3
54
63
8
15
23
31
38
46
9
a
as
i i
46
55
11
22
34
‘3
56
o7
8
16
24
30
39
‘7
is
to
zs
35
4 5
3?
12
23
31
6
15
69
6
16
26
32
40
48
10
19
29
39
is
58
*2
2.3
35
‘7
58
70
6
16
25
33
41
49
10
20
30
40
30
60
12
24
36
45
60
72
a
i i
as
33
42
30
00
20
51
41
I I
61
12
23
37
44
62
74
9
17
U
34
‘3
51
00
21
31
41
52
62
13
25
35
50
63
73
9
11
26
35
5
32
11
21
32
42
53
63
iS
26
39
11
64
7?
9
15
2?
33
44
55
i i
22
33
‘i
so
63
I i
26
39
32
65
is
9
18
27
36
43
54
I I
22
33
44
55
65
13
7?
40
33
67
88
9
08
25
3?
44
35
11
U
34
43
54
67
04
U
ti
34
65
51
9s9z C? • a te 3-L.a it$ntIa
‘9-,

-------
T? .BLE -7
CT VALCES FOR
IN CTrVATION OF v: rJsEs 8? F E cRNtU 2 )
toc Inactivati.on
2.0 3.0 4.0
pH pH pH
Temperature (C ) 6-9 10 6—9 10 6-9 10
0.5 6 45 9 66 12 90
5 4 30 6 44 8 60
10 3 22 4 33 6 45
15 2 15 3 22 4 30
20 1 11 2 16 3 22
25 1 7 3. 3.1 2 15
Notes:
1. Data adapted from Sobsey (1988) for inactivation of ifepatitus A
Virus (}IAV) at pH — 6, 7, 8, 9, and 3.0 and temperature • S C. CT
values include a safety factor of 3.
2. CT values adjusted to other temperatures by doubling CT for each
10 C drop in temperature.

-------
‘IALLtS FOR
INACTV?.TION CF CZAR IA C’iSTS
BY CHLORINE D:OxIDE H 6-
Tem erature tC)
: act va on l 5 10 15 O 25
C.5 log 10 4.3 4 3.2 2.5 2
1 log 21 8.7 7.7 6.3 5 3.7
..5 log 32 13 12 10 7.5 S.5
2 log 42 17 15 13 10 7.3
52 22 19 16 .3 9
3 Log 63 26 23 19 15 11

-------
TABLE E-9
CT VALUES FOR
U C I I VATION OF VIRUSES
[ _ LOR1NE Q OXIDE OH 6 _ 9 2
______________ Tenmerature
Remova ’
2 og 8.4 5. 4.2 2.8 2.1 1.4
3 log 25.6 17.1 12.8 8.6 6.4 4.3
4 log 50.1 33.4 25.1 16.7 12.5 8.4
Notes:
1. Cata adapted from Sobsey (1988) for inactivation of Hepatitus A Virus (HAY)
at pH 6.0 and temperature — 5 C. CT values include a safety factor of
2.
2. CT values adjusted to other temperatures by doubling CT for each 10 C drop
in temperature.

-------
1.
TA LZ. E .iO
CT /ALUtS FOR
:NAcr:vAT:c CF GIA DIA CYSTS
3? CZONE cH 6—9
Temperature c)
nact vat orz ____
0.5 Log 0.48 0.32 0.23 0.16 0.12 0.08
1 Log 0.97 0.63 0.48 0.32 0.24 0.16
1.5 log 1.5 0.95 0.72 0.48 0.36 0.24
2 log 1.9 1.3 0.95 0.63 0.48 0.32
2.5 log 2.4 1.6 1.2 0.79 0.60 0.40
3 log 2.9 1.9 1.43 0.95 0.72 0.48

-------
TABLE E-
CT VALUES
INACTIVATION OF VIRUS \ BY OZONE ’ 1
Temperat. Le (C -
I n act I vat i on j IL IL ZL
2 log 0.9 0.6 0.5 0.3 0.25 0.15
3 log 1.4 0.9 0.8 0.5 0.4 0.25
4 log 1.8 1.2 1.0 0.6 0.5 0.3
Notes:
1. Data adapted from Roy (1982) for inactivation of poliovirus for pH — 7.2
and temperature • 5 C. CT values include a safety factor of 3.
2. CT values adjusted to other temperatures by doubhng CT for each 10 C drop
in temperature.

-------
TABLE E-12
CT VALUES FOR
INACTtVATWN OF GIARDIA CYSTS
BY CHLOR MINLoH 6-9
Inact ivation
Teuioerature
(C)
1
635
5
365
10
310
15
250
20
185
25
125
0.5
log
1
log
1,270
735
615
500
370
250
1.5
log
1,900
1,100
930
750
550
375
2
log
2,535
1,470
1,230
1,000
735
500
2.5
log
3,170
1,830
1,540
1,250
915
625
3
log
3,800
2,200
1,850
1,500
1,100
750

-------
TABLE E-13
CT LUES FOR
: NAcT: ATIcN C ‘J1P 5ES 3 CHLC?X INE t1 ’ 2 ’
er’ perature (C)
5 10 15 — - 25
2 1.243 657 643 428 321 214
3 g 2.063 1 423 1,O6 712 534 356
4 :ca 2,863 1,988 1,491 994 746 497
ote
1. Data from Sobsey U988) for i.nactivation of Hepatitus A Virus (F AV)
for pH • 8.0 an 1 temperature — 5 C, and assumed to apply for pHs in
.ne range of 60 to 10.0.
2. CT values adjusted to other temperatures by doubling CT for each
10 C drop in temperature.
3. This table of CT values applies for systems usirtg combined chlorine
where chlortne j.s added prior to a oni .a in the treatment sequence.
CT values in this table should not be used for estimating the
adequacy of disinfection in systems applying preformed chioramines
or ammonia ahead of chlorine.

-------
TABLE E-14
CT VALUES FOR
INACTIVATION OF VIRUSES BY UVW
Loa Inactivation
2.0 3.0
21 36
Note
1. Data adapted from Sobsey (1988) for UV inactivation of
Hepatitus A Virus (HAy). UrUts of CT va’ues are mw-sec/cm.
CT va1ue nc ude a saftey factor of 3.

-------
APPENDIX F
BASIS FOR CT VALUES

-------
APPENDIX F
BASIS OF CT VALUES
F.1 Inactivation of Giardia Cysts
F.1.1 Free Chlorine
The C T values for free chlorine in Tables E-1 through E-6 are based
on a statistical analysis (Clark et al., 1988; attached to this appendix),
which considered both animal infectivity studies (Hibler et al.. 1981) and
excystation studies (Jarroll et al., 1981; Rice et al., 1982; Rubin et
al., 1988). A multiplicative model was selected to best represent the
chemical reactions during the inactivation process. This model was
applied to each of the data sets, listed above, and in various combina-
tions. The animal infectivity data were included in all combinations
studied. The animal infectivity data was considered essential for
inclusion in all the analysis of combined data sets because it included
many more data points than the other data sets, all of which represented
inactivation levels at 99.99 percent. Because of limitations with the
excystation methodology, only data for achieving less than 99.9 percent
inactivation was available from such studies.
Statistical analysis supported the choice of combining the Hibler
et al. and the Jarroll et al. data (and excluding the Rice et al. (1981)
and Rubin et al. (1987) data), to form the best fit model for predicting
CT values for different levels of inactivation. As a conservative
regulatory strategy 1 Clark et al. (1988) reconcended that CT values for
different levels of inactivation be determined by applying first order
kinetics to the 99 percent upper confidence interval of the CT 99 values
predicted by the model.
The aedel was applied using the above strategy as a safety factor,
to deterstus the CT values ranging from 0.5—log to 3-log inactivation at
0.5 and 5 C. CT values for temperatures above 5 C were estimated assuming
a twofold decrease for every 10 C. CT values for temperatures at 0.5 C
were estimated assuming a 1.5 times increase to CT values at 5 C. This
general principle is supported by hoff (1986). It Is important to note
F-I

-------
that the CT values for free chlorine are sensitive to the residual
concentration, C. For example, at a pH of 7 and a temperature of 10 C,
a 3-log Ciardia cyst inactivation results from a CT of 107 mg/L-min with
a free residual of 0.6 giL and a CT of 124 rng/L-min with a free residual
of 2.0 mg/L.
Application of the model to pf4s above 8, up to 9, was considered
reasonable because the model is substantially sensitive to pH (e.g., CTs
at pH 9 are over three times greater than CTs at pH 6 and over two times
greater than CTs at pH 7). At a pH of 9, approximately four percent of
the hypochiorous acid fraction of free chlorine is still present. Recent
data indicate that in terms of HOC1 residuals (versus total free chlorine
residuals including HOC1 and OCl ) the CT products required far inactiva-
tion of Giardia muris and Giardip lamblia cysts decrease with increasing
pH from 7 to 9 (Leahy et aL , 1987; Rubin et aL , 1988b). However, with
increasing pH, the fraction of free chlorine existing as the weaker
oxidant species (0C1) increases. In terms of total free chlorine
residuals (i.e., HOC1 and OC1 ) the CT products required for 4 n?ctivaticn
of Giardia murii cysts increase with increasing pH from 7 to 9 by less
than a factor of 2 at concentrations of less than 5.0 mg/L (see
Table F-i). Also, the significance of pH on the value of CT products
achieving 99 percent inactivation appears to decrease with decreasing
temperature and free chlorine concentration. The relative effects of p14,
temperature, and chlorine concentration, on inactivation of Giardia nuns
cysts appears to be the same for Giardia lamblia cysts (Rubin et al.,
1988b) , although not as much data for Giardia lamblia cysts for high pH
and temperature values as for Giardia muris cysts is yet available.
F.1.2 Ozone and Chlorine Dioxide
The CT values for ozone in Table £40 are based on disinfection
studies using j vitro excystatlon of Glardia lamblia
(Wickra anayake, G. B., et al., 1985). CT 9 , values at 5 C and pH 7 for
ozone ranged frog 0.46 to 0.64 (dIsinfectant concentrations ranging from
0.11 to 0.48 mg/I). No CT values were available for other pHs. The
highest C l 99 value, 0.64, was used as a basis for extrapolation to obtain
F-2

-------
TABLE F-I
CT VALUES TO ACHIEVE 99 PERCENT
INACTIVATiON OF GIARDIA MURJ5 CYSTS BY FRIE CHLORINE
(Source: Rubin, et a]., 1988b)
Temperature Concentration (mo/U
( C l O 2-O ,S 0.5-1.0 1 . 0-2.0 2.0-5.0
7 1 500 760 1,460 1,200
15 200 290 360 290
8 1 510 820 1,580 1,300
15 220 320
9 1 440 1,100 1,300 2,200
15 310 420 620 760

-------
TABLE F-2
CT VALUES FOR 99 PERCENT
INACTIVATION OF tIARDIA MURIS CYSTS BY MONOCHLORAM INE*
(Source: Rubin, 1988)
Temperature Monochloramine Concentration ( malL )
2± ! IC 2 .0-10.0
6 15 1,500 880
5 >1,500 >880
1 >1,500 >880
7 iS >970 970
5 >970 1,400
1 2,500 >1,400
8 15 1,000 630
5 >1,000 1,430
1 >1,000 1,880
9 15 890 560
5 >890 >560
1 >890 >560
‘CT values with u > signs are extrapolated from the known data.

-------
the CT values at 5 C, assuming first order kinetics and applying a safety
factor of 2, e.g., (.64 X 3/2 X 2 = 1.9). CT values for temperatures
above 5 C were estimated assuming a twofold decrease for every 10 C. CT
values for temperatures at 0.5 C were estimated assuming a 1.5 times
increase to CT values at 5 C.
The CT values for chlorine dioxide in Table E-8 are based on
disinfection studies using jj vitro excystation of Giardia muris CT 9
values at pH 7 and 1 C, 5 C, 15 C and 25 C (Leahy, 1985 and Rubin, 1988b).
The average CT 99 value at each temperature (27.9 at 1 C, 11.8 at 5 C, 8.5
at 15 C, and 4.7 at 25 C) was extrapolated using first order kinetics and
multiplied by a safety factor of 1.5 to obtain the CT 99 values, e.g.,
at 1 C C 99 27.9 x 1.5 x 1.5 = 63.
Because of the limited data available at pHs other than pH 7, the same CT
values are specified for all pHs. Although most of the CT 99 data were
determined at pH 7, it is known that chlorine dioxide is more effective
at pH 9. Thus, the CT values in the rule are more conservative for higher
pHs than for lower pHs.
A lower safety factor is used for chlorine dioxide than for ozone,
because the data was generated using Giardia nuns cysts which are more
resistant than Giardia lamblia cysts. CT values at other temperatures
were estimated, based on the same rule of thumb multipliers assumed for
ozone.
A larger safety factor was applied to the ozone and chlorine dioxide
data than to the chlorine data because:
a. Less data were available for ozone and chlorine dioxide than
for chlorine;
b Data available for ozone and chlorine dioxide, because of the
limitations of the excystation procedure, only reflected up
to or slightly beyond 99 percent inactivation. Data for
chlorine, based on animal infectivity studies rather than
excystatlon procedures, reflected inactivation of 99.99 per-
cent. Extrapolation of data to achieve CT values for
99.9 percent inactivation with ozone and chlorine dioxide,
involved greater uncertainty than the direct determination of
CT values for 99.9 percent inactivation using chlorine.
c. The CT values for ozone and chlorine dioxide to achieve 99.9
percent Inactivation are feasible to achieve; and
F—3

-------
d. Use of ozone and chlorine dioxide is likely to occur within
the plant rather than in the distribution system (versus
cMorine and chioramines which are the likely disinfectants
for use in the distribution system). Contact time measure-
ments within the plant will involve greater uncertainty than
measurement of contact time in pipehnes.
EPA recognizes that the CT values for ozone and chlorine
dioxide are based on limited data. Therefore, EPA encourages
the generation of additional data in accordance with the
protocols provided in Appendix G to determine conditions other
than the specified CT values, for providing effective
disinfection at a particular system.
1.1.3 Chloramines
The CT values for chloramines in Table E-12 are based on disinfec-
tion studies using preformed chloramines and jj . vitro excystation of
Giardia inuris (Rubin, 1988). Table F-2 sumarizes CT values for achieving
99 percent inactivation of Giardia nuns cysts. The highest CT values for
achieving 99 percent inactivation at 1 C (2, 500) and 5 C (1,430) were each
multiplied by 1.5 (i.e., first order kinetics were assumed) to estimate
the CT 99 values at 0.5 C and 5 C, respectively, in Table E-12. The CT 99
value of 970 at 15 C was multiplied by 1.5 to estimate the CT 99 value.
The highest CT 99 value of 1,500 at 15 C and pH 6 was not used because it
appeared anomalous to the other data. Interesting to note is that among
the data in Table 1-2 the CT values in the lower residual concentration
range (<2 mg/L) are higher than those in the higher residual concentration
range (2-10 mg/L). This is opposite to the relationship between these
variables for free chlorine. For chloraxnines, residual concentration may
have greater influence than contact time on the inactivation of Giardia
cysts within the range of chioramine residual concentrations practiced by
water utilities (less than 10 mg/L). No safety factor was applied to
these data since chioramination, conducted in the field, is more effective
than using prefoni ed thioramines. Also, Giardia muri s appears to be more
resistant than Glardla lamblia to chloramines (Rubin, 1988b).
1-4

-------
F.2 Inact ivation of Viruses
F.2.1 Free Chlorine
CT values for free chlorine are based on data by Sobsey (1938) for
inactivation of Hepatitus A virus (HAV), Strain HM175, at pH 6,7,8 9 and
10, chlorine concentrations of 0.5 to 0.2, and a temperature of 5 C, as
contained in Table F-3. The highest CT value for the pH range 6-9 for
achieving 2, 3 and 4-log inactivation of HAV were multiplied by a safety
factor of 3 to obtain the CT values listed in Table E-7. (e.g., the CT
value for achieving 4-log inactivation at pHs 6-9 was determined by
multiplying 2.55 X 3 7.6 8). The CT va’ues at pH 10 were significant-
ly higher than those for pHs 6-9 and are considered separately. The CT
values in Table E-7 for pH 10 also include a safety factor of 3. CT
values at temperatures other than S C were determined assuming a two fold
decrease for every 10 C increase. CT values for inactivating viruses in
general are based on HAV data since they g ve higher CT values than those
for ir’activation of polio and rotaviruses under similar conditions of pW
and temperature (Hoff, 1986).
F.2.2 Chlorine Dioxide
Data by Sobsey (1988) for inactivation of Hepatitus A virus, strain
HM 175, by a chlorine dioxide concentration of 0.5 mg/l at pH 6 and 5 C
is shown in Table F-4. The CT values in Table E-9 for pHs 6-9 and
temperature 5 C were determined by applying a safety factor of 2 to the
average CT values presented in Table F-4 at pH 6. This safety factor is
lower than that used to determine CT values for chlorine because chlorine
dioxide appears to be significantly more effective at higher pHs and most
waters are assumed to have a higher pH than 6.
CT values at temperatures other than 5 C in Table E-9 were
determine4 by applying a twofold decrease for every 10 C increase. The
data for pH 9 was not considered because it is very limited and other
viruses are more resistant to chlorine dioxide than Hepatitus A is at pH
9. According to Hoff (1986) at a pH of 9 and a temperature of 21 C a CT
of 0.35 provIdes a 4—log inactivation of poliov lrus 1. Applying the same
F- 5

-------
TABLE F-3
CT VALUES FOR INACTIVATION OF HEPATITUS A VIRUS
BY FREE CHLORINE
(Source: Sobsey 1988)
LOG INACTIVAT ION oH
2. 1
2 1.18 0.70 1.00 1.25 19.3
3 1.75 1.07 1.51 1.9 14.6
4 2.33 1.43 2.03 2.55 9.8

-------
TABLE F—4
CT VALUES FOR It ACTIVA1ION OF HEPATITUS A VIRUS
BY CHLORtNE DIOXIDE ( 5085EV 1988)
pH6 2
3
4
Experinient
No.
I
2
3
4
1
2
(rrin
Experiment No.
1 2 3 4
Initial
0.49
0.50
0.51
0.51
0.5
0.5
12 9 5 7 3.8
30 29 22 20 9.4
55 59 43 39 17
Ave r g
0.32
0.33
0.36
0.37
0.5
0.5
pH9 >2.5
0.33
--
-—
--
<0.17
--
<0.17
>3.6
0.33
——
——
——
<0.17
—-
<0.17
1. CT values were obtained by multiplying inactivation time by the average
concentration shown above for each experiment.
ClO, Ccncentr tion (n1Q1L
pH6
pH9
Inactivation Time
Log
Inactivation
N’
Average
1 2 3 4 CT
3.0
1.8
2.6
2.8
9.6
7.9
7.4
8.6
20
16
14
16.7
Note :

-------
safety factor and rule of thumb multipliers to this data results in a CT
of 2.8 for a 4-log virus inactivation at 0.5’C, in contrast to a CT of
50.1 resulting from the Hepatitus A data at pH 6. Therefore 4 in order to
assure inactivation of Hepatitus A, the higher CT values are needed.
Systems with high pHs may wish to demonstrate the effectiveness of
chlorine dioxide at lower CT values based on the protocol in Appendix C.
Chlorine dioxide is much more effective for inactivating rotavirus and
polio virus than it is for inactivating N M (Hoff 1986).
F.2.3 Ch loramines
The CT values in Table E- 13 at 5 C were based directly on data by
Sobsey (1988) using preformed chloramines at pH 8. No safety factor was
applied to the laboratory data since chlorainination in the field, where
some transient presence of free chlorine would occur 1 is assumed more
effective than preformed ch loramines.
HAV is less resistant to preformed ch loramines than are other
viruses. For example, CTs of 3,800-6,500 were needed for 2-log inictiva—
tion of simian rotavirus at pH 8.0 and temperature — 5 C (Berman and
Hoff, 1984). However, these same viruses are very sensitive to free
chlorine. CT values ranging from less than 0.025 to 2.16 were required
to achieve 99 percent inactivation of rotavirus by free chlorine at pH
6-10 and temperature 4-5 C (Hoff, 1986). HAV is more resistant to free
chlorine than are rotaviruses.
The CT values In Table E-13 apply for systems using combined
chlorine where chlorine is added prior to aemonia In the treatment
sequence, This should provide sufficient contact with free chlorine to
assure inactivation of rotaviruses. CT values Table (-13 should not be
used for estimating the adequacy of disinfection in systems applying
preformed chioramines or amonia ahead of chlorine, since CT values based
on HAY inKtivation with preformed chloramines may not be adequate for
destroying rotaviruses. In systems applying preformed chloramines, it is
recomended that inactivation studies as outlined In Appendix C be
performed with Bacteriophage 14S2 as the indicator virus to determine
sufficient CT values. Also, the protocol In Appendix 6 can be used by
F-6

-------
systems applying chlorine ahead of aninonia to demonstrate lower CT’s than
those indicated in Table E-13.
P.2.4 Ozone
No laboratory CT values based on inactivation of MV virus are yet
available for ozone. Based on data from Roy (1982) , a mean CT value of
0.2 achieved 2-log inactivation of polfovirus I at 5 C arid pH 7.2. Much
lower CT values are needed to achieve a 2-log inactivation of rotavirus
(Vaughn, 1987). No CT values were available for achieving greater than
a 2—log inactivation. The CT values in Table E-11 for achieving 2-log
inactivation at 5 C were determined by applying a safety factor of 3 to
the data from Roy (1982). CT values for 3 and 4-log inactivation were
determined by applying first order kinetics and assuming the same safety
factor of 3. CT values were adjusted for temperatures other than 5 C by
applying a twofold decrease for every 10 C Increase. Based on the
available data, CT values for ozone disinfection are not strongly
dependent on pH. Therefore, data obtained at pH • 7.2 Is assumed to apply
for pus in the range of 6.0 to 9.0. However, it should be noted that the
maintenance of an ozone residual is affected by pH.
P.2.5 Ultraviolet Light ( J 1
The CT values for inactivation of viruses by UV are based on studies
by Sobsey (1988) on inactivation of Hepatitis A virus (HAV) by UV. These
data were used because MV has been established as an important cause of
waterborne disease. The CT values were derived by applying a safety
factor of 3 to the MV Inactivation data. The CT values In Table E-14
are higher than the CT values for l i v inactivation of poliovirus 1 and
simian rotavinis from previous studies (Chang et al., 1985).
P.2.6 Potassium Pennanganate
Potassium persanganate is a co only used oxidant in water
treatment. Preliminary testing by Yahya, et al 1988, tndicates that
F-i

-------
potassium per vnanganate nay contribute to virus inactivation. The test
data included in Table F-S indicates the inactivation of bacteriophage
MS-2 using potassium permanganate with a pure water-buffer solution.
These data do not include safety factors. It is likely that CT values for
actual water treatment processes will differ from these values. This data
has only been provided here as an indication of the potential of potassium
permanganate.as a disinfectant. It is not meant to be used as a basis for
establishing CT requirements.
References
Berman, D. Hoff, J. Inactivation of Simian Rotavirus SA IL by Chlorine,
Chlorine Dioxide and Monochioramine. Appl. Environ. Microbiol.,
48:317-323, 1984.
Chang, J.C.H.; Ossoff, S.F.; lobe, D.C.; Dorfman, M.H.; Dumais, C.M.;
Qualls, P.C.; Johnson, J.D. Inactivation of Pathogenic and Indicator
Microorganisms. Applied Environ. Micro., June 1985, pp. 1361-1365.
Clark, R.M.; Read, E.J.; Hoff, J.C. Inactivation of Giardia lamb ]i by
Chlorine: A Mathematical and Statiflical Analysis. Unpublished Report,
EP4/600/x-87/149, DWRD, Cincinnati, OH, 1987.
Clark, P.; Regli, S.; Black, D. Inactivation of Giardia lamblia by Free
Chlorine: A Mathematical Model. Presented at AWWA Water Quality
Technology Conference. St. Louis, Mo., November 1988.
Hfb!er, C. P.; C. H. Hancock; 1. H. Perger; J. C. Wegrzn; K. 0. Swabby
Inactivation of Glardia cysts with Chlorine at 0.5 C to 5.0 C American
Water Works Association Research Foundation, In press, 1987.
Hoff, J. C. Inactivation of Microbial Agents by Chemical Disinfectants ,
EPA/600/52—86/067, U.S. Environmental Protection Agency, Water Engineering
Research Laboratory, Cincinnati, Ohio, September, 1986.
Jarroll, E. 1.; A. K. Binham; E. A. Meyer Effect of Chlorine on Giardia
lamblia Cyst Viability. Appl. Environ. Microblol., 41:483—487, 1981.
Leahy, J. G.; Rubin, A. J.; Sproul, 0. J. Inactivation of Glardia unuris
Cysts by Free-Chlorine. Appl. Environ. Mlcrobiol., July 1987.
Rice, E.; Hoff 1 3.; Schaefer, F. Inactivation of Giardia Cysts by
Chlorine. Appi. and Environ. Microbiology 1 43:250-251, January 1982.
Roy, 0., R.S. Engelbrecht, and E.S.K. Chian. Comparative Inactivation of
Six Enteroviruses by Ozone. J. AWWA, 74(12):660, 1982.
F-B

-------
TABLE F-5
CT VALUES FOR 2-LOG INACTIVATION
OF MS-2 BACTERIOPHAGE WITH POTASSIUM PERMANGANATE
KMnO
ni /L) pH 6.0 DH 8.0
0.5 27.4 a” 26.1 a
1.5 32.0 a 50.9 b
2.0 ND 2 53.5 c
5.0 63.8 a 35.5 c
Notes :
1. Treatments with different letters are significant different.
2. Not determined.

-------
Rubin , A. “CT Products for the Inactivation of Giard ip Cysts by Chlorine,
Chloramine, Iodine, Ozone and Chlorine Dioxide” submitted for publication
in U. AWWA, December, 1988b.
Sobsey, N. Oetection and Chlorine Disinfection of Hepatitus A in Water.
CR-813-024. EPA QuarterSy Report. December 1988.
Vaughn, U.; Chen, Y.; Lindburg, K.; Morales, 0. Inactivation of Human and
Simun Rotaviruses by Ozone. App I. Environ. Microbiol., 53(9):2218-2221,
September 1987.
Wickramanayake, G.; Rubin, A.; Sproul, 0. Effects of Ozone and Storage
Temperature on Giardia Cysts. J.AWWA, 77(8):14—77, 1985.
Yahya, M.T., 1andeen, L.K., Forsthoefel, N.R., Kujawa, K., and Gerba, C.P.
Evaluation of Potassium Permanganate for Inactivation of Bacteriophage
NS-2 in Water Systems. Copyright 1988, Carus Chemical Company, Ottawa,
Ill i no is.
F-9

-------
A ?L TI L AND S TISTICAL D V ’I
OF GIARDIA LA LIA BY FR Qfl ORD E
by
R ert M. Cla. k,a
D WCI’ION
The 1986 azr r erits to the Safe Drinjdsq Water Act (St ) r .tire A to
pr iJ.gate prin&y drinkirg water r ulations (a) sç ifyirq oriteria r er
wh.ith filtration s 1d be r uir , (b) r juirir disinfection as a trea nt
t nique for all p b1ic water systers, ar i (c) estab1J.shii axi tam—
inant levels (1 a) or treat nt requiz nts for t l of Giax iia larrblia ,
viruses, I ionella , heterotr ic plate t bacteria, ard turbidity. ‘A
has prcços surface water trea nt t nique r uir ts to fulfill the
S requireu nts for systers usis surf a waters)’ itional r u.latiors
specifyix disinfection r iire ents for systa s usir gr rd water s r
will be prcçosed ard pr a lgat 1 at a later date.
Urder the prtçosed surfac2 water trea t rule (SWIR) all mirdty ard
r r .zn.ity piblic water syst 1d be r irul to treat their surface
water s r to tro1 Giardia laitlia , teric vir es ard patl garLic
bacteria. miniiia r iir 1 treatment for ea faca water o.zld 1z l x e
disinf ti In a iti , w less the s water is wall otect ard
aDirector Drmnk1i ter eard Divisi , Risk tic s erirq
Iafrratozy, 26 W. ? xtin Luther Klxrj, Clxcirmati, thio 45268
kISEPA, Of fi of Drinking 1 ter, 401 M Streat, S.W., Washin3tcm, DC 20460

-------
i ets certa.th ter q . ality iteria (total or f .l lifor aid itidity
1i its), req4red ea nt 4d also lzcli.de filtratiai. The trea rit
provided in any se, .ild be required to a Lieve a 99.9 per r t r a 1
aid/or inactivati of Giard.ia laxrblia cysts, aid at least 99.99 per nt
r val ar4’or inactivati of enteric viruses (i.e. viruses of fe l origin
aid inf ti s to kn ar ). Unfiltered syst axe required to d trate
that disinfectici, ala athieves the minis.u perfor z r iir x nts by
uaiitorix disinf tiant resi’ 1 (s), dis1nf t cxrit t i (s), (if
dilori is used), aid ter ipi ratzre, aid a ly1n these data to dete ir
if there “Ct” value (the prod t of disinf tant ic itrati ( /L) aid
disini tant c xtact (mir ites)) equal to the Ct value ified in
the rule. Ct value spictfied In the rule. The Ct values r y
to athieve 99.9 pex it inactivatia of Giardia l lj cysts by vari
die inf tant aid r vari diti are sp ’ified in the
With the e ti of d laremirEs, ere a ia j 3 4 4 prior to thlor ,
these C t valt are also ate to athieve greater than 99.99 pe .ent in
activati of viruees.
lbr filtered syet , states are rs iired to ify the level of
disInf ti for .yst to ze *t their sra11 treatm it athiaves
at least 99.9 aid 99.99 pur .*nt r a.t aid/or ir ivati i of Giardia
li lia cysts aid vtha , jr c tively.
In m Giidm ? nal of _. re -- .—’iM C•t val% for
diifu .iit lltinf&taiits to a ievs diffare t in .ivatici , aid
per’ . t Ji ivatia th_at filtered syvt i1d ivs es a of
fil atia t. wwli aid ‘ ter q 1 (ty a rgtttia . 2
Glands 1 is Is a of the t reaistant oripnl to dialnf.±im by
2

-------
1orir f zd in ter. Therefore, a di intar t and effort has b devot
to the determinaticm of Ct vaI for Giaz ia laxblia .
Many factors inf1uez Giaxd.ia 1 lia reacti kineticm. Ptd effort
.s made to deve1 an ad uate to d cribe Giardia 1an 1ia reacti s
with fr d 1orir , and then to estimate the r 1 para ters. This paper
dis is es the de1 us for develcçizq Ct values in the SW and the
ass iat Q4daz Mar ia1.
ct ai r
In rir the bio ’i eff tiv sa of disinfectants, jor
sideruti axe the disinfactarit t ticm aid tii* to attain
1nactivatia of a c*rtain pu orti of the pcp laticr poe w r ifi&1
tia . - NC•t 1 w. )t that is in aa tt t e is an e piri 1 aticm
st inirq fran the early x c of tsa aid is çreas as: 3 ’ 4
K”.C t (1)
K - ca’stant for a ific icroorgani cpze 1 wder ific
c dit
C — disinfactant tiaticm
n — tant, also the “ eff4r i t of dilut1 ’
t — the ti r .iir for a fI ni inactivaticE
It is bas vm ’t II ff aaticz tmed for dsta inirq r z’e of
d i 1 r tiQ In i4 jd the va1 of i detst ir s the or of d” 1
1I t.t at this ti ) to distnf.ctIm t atixitea r iirea ilti.ple
çsrI ts &*rs * sffsctiv at ae rsre1 iabIea, i I( t mv-
tizs, aid d44I f Aflt z tiatia era to tstwir* t i tiW
at fact the Ii ivati of aic ± ia1 t Equ . fl* Value of ii is a v y
3

-------
i ortarit factor in dete.r inirq the d r to e c po] .atta of data
fr disi ti eç er 4 z nts j 5 i, Jj 7,8,9
FACI AF X’DG Ct
the d tn ti of pathcqens by thlcrinaticm is dq ezx3er t a a
of factors, xr.1u’11rg s ter t m ratue, disinfactant itact t ,
dwjree of mixii q, t bidity, pr e of intarfer xq betaz , a d -
c ntz atia of i1orir available. fi eiaUy, has a si iifi rzt
eff t i thactivatic* efficiercy bt n e it detersir the ies of
düorix f .ud in scluti t , eath of thid has diffex it 1j tivati
effi y.
i ” t Of t ç rature a disinf tiat .iilci y is also sic ifi-
cant. For e iiple , Clarke’s rk in virus txutia by d lorir thlicates
that cxa-itact tire uz t be ircreasel o to thr the t ç’ ra u e
is l r 10 C 10 Disinfactia by cthlorinati can inactivate Giaxd.ia
cysts, bit a 1y w r riqor is axditicz . ) st r tly, }bff et al.
cl that (1) th e cysts are ams the t r istant patheg )c n,
(2) disinfacticm at 1 i th ,eratzr is e i lly diffi .lt, anl (3) treat-
xnt prior to disinfacti axe j rtant.
Jarroll at al. • min vi statia to t irm cyst viability,
t t eat than 99.8 of Giardia cysts n be kiUe
by c s to 2.5 JL of thlorii for 10 alzaat at 15 C anl [ 11 6, or aft
60 alait 7 orS. At 5 C, e,qr ir . to 2 a j1 of dl.oriz kill 1 at
least 99.8 p * of al.l cysts at 6 m d 7 aft 60 frutss. bI il . it
rsq.iix 8 JL to kill the s &* .a1ta s of cysts at 6 wd 7 aft 10
dnztas, it r iir 8 JL to lj ivats cyst. to level at S
a2t 30 eiriat. C t va1 for 99 p.j .a.it 1sa ivatia k of Giazdlh 1 1ia
4

-------
by tree cth1crir at di.fferer t t erat .u az I va1 are sh in ir Table 1.
Inactivati rat ea.s i at 1 r t era ir ar at hi er v 1
as ir 1i t by the hi er Ct va1ue . Fi tzee 1 eM 2 fr Jarroi.1 et
a].. ‘s r1c iil ate s of t] e effects. 12
.ELE 1. Ct VAW FOR 99% r criv na OF C IARDIA
LAMBLIA C STS 8
Disinfe tant
Texç e iU tia Tiiie 1 an No. of
C) I (r JL) (Lu ) Ct Ct 1 ç.
5 6 1. 0 —8 .0 6—47 47—84 65 4
7 2.0-8.0 7—42 56—152 97 3
8 2.0—8.0 72—164 72—164 110 3
15 6 2.S—3.0 7 18—21 20 2
7 2.5—3.0 6—18 18—45 32 2
8 2.5—3.0 7—21 21—52 37 2
25 6 1.5 <6 <9 <9 1
7 1.5 <7 <10 <10 1
8 1.5 <8 <12 <12 1
D L n ivr i
Hibler at al. Wr 1ian gethils to detaz ir* the effects of
thlorine . 1 1ia cysts. 1 - 3 In a seri of ri zts, cysts a
a far vari .a ti ri s to tree d 1 Lr. itreticr E 5Z iTJ
fr 0.4 to 4. ‘L at 0.5, 2.5, aid 5.0 C aid 6, 7. aid 8.
geztila 5z i0 of the dilarb a,qxeeI cysts aid bo xtly
ea iz far of infacticri. Six U* teet artieels h
r ivui a of S x d 1ar1s t cysts d & 3 inf ivity atLdiee
vith i 1ar1i t.1 cysts that a çr cit.ly 5 cysts 11y tibit
an nfectivs s, foU thg es icz s - vd ii *
S

-------
CHI.0RU41 CONCE$T*A flQM5
• I mg/i
2 mg/I
o 4 mg/I
• $ mgiI
FIGURE 1.
INACTiVATION OF G. LAMBLIA CYSTS BY
FREE RESIDUAL CHLORINE AT 5°C
CONTACT TIME (m nutss)
C 4LCqINE CONCENTRATIOsS
0 3.0 mg/I
• 2.1 mg/I
FIGURE 2. INACTIVATION OF G. LAMBL1A CYSTS BY
FREE RESIDUAL CHLORINE AT 15°C
S
)I.
U
z
U
4 ’
CONTACT TIME (mUiut.i)
DM1 pMS
-a
S
=
‘I .
U
U
w
4.
6

-------
infetivity petter o rrir in tha a ii 1 r ivin thlorthe e3ç ad
cysts. If all five a 4 ” ’ 1 - re x f tei, t it s as that the
C t had pr less that 99.99 percent ir tivaticm ard if r aiü 1s
‘ re ijifectad, that it had pro± greater than 99.99 percent inactiva-
tiai. It is i1r,r ib1e to deternth tha t level of ir ctivati i for
these r lts. If, var, 1-4 api i g re infectad it s - - ‘ 1 that
tha level of viable cysts e 5 per ani, sl &xl that 99 • 99 percent of tha
origir .l cyst p p 1ati i had been inactivatel.
}Libler interpolated fr tha r lts an2 pr i 1 r ive
tables at in Ct values at 0 • 5 C t perathre intervals. P ti g t of
±servaticr idic tizç that Ct val ii easad as thlorir t t-
i iz eased within the rarqe of diloriZE t tim ad, Hibler at
al. advised iz t e of tha Ct val far d larir tt ti z
above 2.5 JL.
Thble 2 arizes Kibler’s data for tha diffe t e çeri ital
i1itia lt i 3 s s t.ha rar of th.lorir t ati
in /L to cysts re qx ad before being fed to U gethils, ad
1t t 7 — a mx*er of e3çeri its iith yi dM 1-4 infected gerbils
.it of 5. 1i 4 tha reri of cyst ‘q ’ ire ti &d Q 1t i S
rtair - rar of Ct values that are . t of U - di1ari
& cyst . . .
7

-------
‘ &Z 2. Ct VALI3 F 99.99 1 D CFIV TI J AS
clJ AN L n wriviri m
Rar e of
r e of Cfst ! qx sure Rar e of of ffLm r of
r p. O3 c. Ti Ct values fr i Prsiict Ct serva-
C ta Ct Values ti
6 0.5 0.56—3.93 39—300 113—263 136—192 25
6 2.5 0.53—3.80 18—222 65—212 107—151 15
6 5 0.44—3.47 25—287 50—180 93—134 26
7 0.5 0.51—4.05 75—600 156—306 205—295 14
7 2.5 0.64—4.23 55—350 124—347 169—235 14
7 5 0.73—4.08 47—227 144—222 156—211 15
8 0.5 0.49—3.25 132—593 159—526 294—410 22
8 2.5 0.50-3.24 54—431 175—371 233—324 21
8 5 0.48—3.67 95—417 200—386 209—299 15
Hibler’s data is bas 1 . aninial Infectivity it has great ççea1 In
t of .1a . 1atirq Ct values for p sib1e regulatory uea. This ar ] .ysis
is pres tad in the follcMirq secticm.
s i ri Lxsis
first att t to analyze these data s by e of a Tessi 4 1
that l x atea itratia t, rki ar te ratwe, as’.miirq that all of
these data re for 99.99% inactivatic . This del is as foU s:
t — (2)
re
t — ti to 99.99% 1nactivati as t 1i ani 1 infectivity
C — ‘c itraticm of disinfectant
— at iJt4jd çeri it s
• atn . at tiid çerl t
R,a,b,c • t.ant$ fr ro icm
A log ran.if of ti % 2 yi.1 :
log (t) — log(R) + a log(C) + b log( ) + a I (t ) (3)
irq log to 10.
a

-------
Fittin aticm 3 to the 167 data pints, thith yie1 ’l 1-4 inf t gerbils,
r .i1ts in the para ter estinates di 1ay in Table 3
.&E 3. FARN i E i ria 3
Pzter Estinate Si ifi r Level
log R -0.0067
a —0.8242 0.0001
b 2.7519 0.0001
C —0.1467 0.0001
R-S .RE of 0.80 for the fitt aq . atia 3 is the pr rticr of vAriability
in log (t) a it for by the fitt fDr the p e of pru1ictir
Ct values eq ati i 3 s as fan 1 back to the ai1tip1i tive fo arx1
iai1tip .1i i by C yield.frag the fol1 i’ir pr ictive aticr :
CtsRC pHbt rç (4)
tit itin the raaeter estinates c±ita ft the g iczi analysis
into .ati i 4 yields:
C t — Q 9 847 C 0 1758 2.75l9 ,—0.1467 (5)
Cblt 6 in Table 2 c tair - predicta C’t v 1i for the arU 1 infec-
tivity date iairq ati m 5.
q ati t 2 be m to be iiva1e it to s iatia 1 (b ta ’s
L ) by div4Ab. b a4 of ati 2 by ‘.C ’ j& 4 yields:
C t .‘Rfê t4II rP (6)
a atw* aid a tant t • that
(7)
E — (8)
9

-------
tbez
c_at_K (9)
If let -a • n in s uaticxt 1 then e aticm 2 n be s n to be 4valent
to uati i.14
pruvicx analysis as art inf tivity level of 99.99 percent.
1 ver, the r ilts (1-4 ari 1 inf t ) 9V t a slcçe bas ut macti-
vaticzt level as a possible iticz a1 variable in ati t 2. M altex te
a roadt s att ta1 usix a cyst inf tivity del. 1?rYi 1
the t prthable ri er (?‘ 1) of viable cysts rç 1i f any given c xd .t-
tire as:
— (1/d)ln(5/(5-P)] (10)
re P is tbe r,m& er of infected an{ ll aid d is ptthability of infec-
tia t ( a & ted by Hibler to be 0.2) . tsirq ati 10, the percent macti—
vati oc iata1 with the r r r of jy f ct &iiw 1c (1-4) n be tl te
as s n in Thble 4. a in tes the izT irg u r of viable
cysts before dlormnatiort is 50,000 per aninal. This a cad io.ild aflc*
f the Ii c&ati i of Iz tivatior Lwel in equatior 2.
&E 4 • ? ED S F V7 RIa.E ?U Dff
(as miirq wix nfu1 probability of infectior i& s 0.2)
* of mt
(of
Ani 1.s N W $ of V1Ahl
5 t 1) Cysts
Ir .ivat1
Iaw 1
% Ir ivatior (*)
1
2
3
4
1.115
2.555
4.581
8.045
0.00O 2
0.000051
0.000092
0.000161
99.99777
99.99489
99.99084
99.98391
*% IMctivati — 100 - p 4 x 100/50,000)
10

-------
Thble 4 the ? I4 of viable cysts &d the percent inactivaticr as a
trcticr of inf tM n. rs of ani 1s. It cen be s that 3 infectal
e1iir t e cUy 4 lcqs inactivaticm. valu in Table 4
i ly a slcçe to the a ve ard further iii 1y that the iti of inactivatia
level to the r re sia aticzt o.ild be Jrthle.
In order to ir p sible d1 r rr L. in this analysis the - mç ’-
tiQ s t t as fo11 s. Table 5 s the n Ct vali ver arn l
JsLf e ctai.
.E 5. ! N C t VALVES V S ?ND9J.S
ArLl .ls Infectai
4
3
1
2
Ct Va1i
160
193
226
242
For the 1 analysis to be istent the n C•t va1 s ui1d be in
the order: 4 <3 <2 < 1. I ver the n Ct val for 2 an1 ls
infected is greater than for 1 ani .l infected. ‘flmrefors t-t ts re
cEr ted ig the ver . levels of infectivity to xi1t are the Ct val .
As n ha fr Table 6, it is r t in y ’th1 . at the 0.05 level of
ai ifi to l* t the levels of inf ivity are all diffare t as
as _
‘a z 6. T-’ IS ._ D ) N
Ct VALVES OG D FW’i JQ 5
D fectivity Level p-Va lia
1 vs. 2 0.3669
1 vs. 3 0.1127
1 4 0.0151
2ve.3 0.0454
2 4 0.0061
3 • 4 0.1763
11

-------
As a ftzrtber t t of the ass zçtici , that an )‘ l esti.n te of viable
cysts mild be . to differentiate q ii s of ar i . . _ inf t , the
95% *fi. intermls re c lc ilata as s n be1 i.
&Z 7. 95%
mi v is
P 4 EI’IPc a
95%
A prt d. te fiderz
No.
of
Inf tai
Ani ].s
MW
of Viable
I ntervals
(of
5 total)
Cysts
L r U par
1
1.1.15
0.0 5.7
2
2.555
0.2 8.5
3
4.581
0.7 13.4
4
8.045
1.5 23.7
‘ fid intervals vvided by Wild, Statistician, C auter
Scie O rp.
The error r1s the tinat.es are wide that it .zld be diffio lt
to lu e that n estixmte per nt in tivatia vez mers of
inf t ar 4 ’ 1 bes’ a this cr t .
AltIu4 tha jji. t of irq tha Mibler deta set to i z.zte a a1 ci to
tha Ct level bead i ard l inf tivity is a p ’l 4 rq it t d a t r t to
be statisth 1ly def .th1e. , tha of irq deta ooUwtad
at ot ii jvatim levels (oU than 4 1 ji .iveti xi) is irab1a
if tha ‘ e1 Ia to be _______ for pr 1I.ctJ 1z ivstic levels.
fls.a an at 1 * - — - to inveeti ta — • - t e of • av 11 hl . deta sets
for this pg.
12

-------
Several data sets re cu ider as a data k ae for lc iri a
pr ictirq Giaxd.ia 1 bUa cyst ir ctivati : Jarrofl,, Hibler, Rice, ard
g jy l2 ,l 3 ,l 6 ,l 7 data e rts of Hilber’s are all. a
e ystati i it ies.
} ff et al. c are *ise inf tivity ard e aystatic i for deter!xlirtirq
the viability of G. ris cysts pc i to th1oriT ard reprtal that both
n tJ ds ve s ilar re 2ts. 12 ystatia t ±3niqJ ail for easier
a e of cyst vi.ak>ility than ar 1 inf tivity sb i{ . I ver
of Limitati with tha e ystatic th 1c ’, cr 1y cu itia rw ry
for athiec,ixq 1 s than 99.9 r nt thactivat.ia available for t e
Thble 8 ita1z a r ry d az terizaticm of u thith
t e data sets re bas’ .
Z 8 • OF . L TA F
D C IVP TIQ $1UDIF T.E D D l IcITVE ) S
I fex Cyst Viability
No.
12 Sy t tic ystati iv iti a.l
v±va1 a ves
ip1e
r 1ea. d
point — 0.1%
wviva1
13 GQr iTh , apt thil i fsc- aviva1 ves.
fr infect tivity (10 4ioint a *it
rs. a c a ] . ’ 0.01* viva1
a-
16 Sy tic ard ystat1a w t 1
r y t c viva1 a
Ib a a 1tipl
ad
— 0.1%
a viva1
17 G.i+i1 t. &1a 1 t ws tia 1
fr inf t øitvival
Iz . (Sav a1 w4tip 1
iaolat ed) —. ad
— 0.1%
* ta prwi r 1k. Jdm ff tLirm..rly of L .
13

-------
‘ first q. seti i to arise is the statistical o etibi1ity of the data
sets. e of the size of the data set ard the fact thet it is bes€d
ar l infectivity, thid is a e direct irdicator of cyst viability t
e.xcystati ’i data, the Mible.r data s 8idered in all inati eva]uatal.
fl a road . s to stn t an Ixdicmtor rar variable to e the
regre si inter t slc e to o ata f data set diffexei .
si %ifica1 of the irdicator rar variable ld su port the hypoth is
of diffezwrt reqresai t irfaoes, i.e., lzrr. itibility of the data sets
irdicator rar variable .a eat in a as to a1 ye
differentiate he i the Mibler data set ard ctk data sets ider 1 ard
to e the r sesi intervept. ixdicator rez variable a defir 1
as fol1 :
Oi.fKiblerdata (11)
z— (
1 if other data
Therefore atici 2 s dafir as fo1l :
t - R leCtac/llOer (12)
re t, C, ç , t are daZin as in tia 2, I — lnactivati level at
— t (ratio of organi friactivatai to or ni at ti zero) aid
R,a,b,c,d - tGrits datarizdx 1 ft regr ica . ticm 12 is ____
as foll :
1c t — 1 R + a l I + b 1 C + c 1 8 + d 1 ta + .Z (13)
In . atjgm 13 ard 1.3 — 0 .*tia 1 .2 is daflza’i the MIbler data
set, aid
tRI t (14)
*t — 1 s t 3.2 ii fii __ r bda data aid
(15)
14

-------
Table 9 di 1ays the data set inattcr as regressicm diagrcstt .
Note that z is the jrxiicmtor rar variable.
‘ i tor tar variable for the intaz t variable i. iz the
Mibler, Jarrol.1 data base as rct signifi rtt (p-’ fal 3372) All other
data bas’- idar 1 h a sigrzifi nt imiicztor rar variable at the
0.05 level of si nificarce. A forn l tast for differ s of irrter t
ar4/or s1 e the Hibler ard arroll data sets aa Ebxt a id r
ditfere e s det te . miS, stat1atij 1 a lysis rta the e of
the H b1er Jar o11 data base for ectar iog the 1 deve1 t aid the
para tax in s uaticzi ii. re ze- ti t wli t o data.
Usiog the a th dis ’ ’ earlier r texs for .aticxt 12 re
ti ted zeø ltir in the fo1lcv4r atim:
t • 0.12 r 027 , O.8l p 2 54 t pO•] 5 (16)
c t — o.i r° c 0 t 2.54 t 0d5 (17)
Thbl 1 aid U. rize the para t seti t aid di etic
stat.istic for the . att zi. ‘fl fit of l * pd, with
rersesia variabise 1ain1rq 86% of veriatia * In log (t).
15

-------
.BT.Z 9. oi ric I2S D 11 sEr D 2 Ia A L1SIS
ta sets ider
R-Sc are
Variables
Plots
—
Hibler, Rice, Jarroll, R b n
Hibler, Rice, Jarroli., 1 bin, 2
0.6801
irrter t, t
i ifi nt
xu -r data
r- tant var
0.7316
interc ,t, ta ç
rt—si ifi nt
rxx -r r .t data
iu - tar t var
Hibler, Rice, I bin
Hibler, Rice, Rabin, 2
0.6649
inter ,t, t p
r t-si iuicer t
r -wr ra1 data
z - tant var
0.7899
intercept
r t-si ifi nt
r -r .n 1 data
r -c r tar t var
flibler, Jarxoll, b ibin
Hibler, Jarrofl, bin, Z
0.6424
interc ,t, taip
i ificant
ra -t r 1 data
ra - tant var
0.6879
intercept, tarp
r t—si ifi nt
data
r i— stant var
Ribler, Rice, Jarroll
Hibler, Rice, Jarroll, 2
0.8619
all variables
signifi nt
r —r r 1 data
ra r- tarrt var
0.865
all variables
si ifi rrt
r -r r 1 data
n -tant var
Hib].er, bin
H .ibler, birt, Z
0.6483
tarp
r ,t-ei ificent
IU — 1cjnii 1 data
iu tant var
0.7593
intex t
r t—si ifi nt
1u -vaxi l data
var
Hibler, Rice
Hibler, RI , 2
018548
all variables
siticent
data
w var
0.8678
*11 vaziablea
ai zdficerit
data
tant var
-
Hibler, arra1l
Hibler, Jarroll, 2
0.8452
all variables
si i
r iw l data
var
0.8459
2 r t
ii ific rit
r- - . . .&i data
tant var
16

-------
&E 10. PARJ ME1 TI?V F D .ThTIa 12
Varja 1e
Parax ter
tiz ate
Sta1x axd T f I :
ror Para t.er-0 B>
Variart
Infl .ati
DfFE P
1
—0.902
0.200 —4.51.8 0.0001
0.000
L 1
1
—0.268
0.014 —19.420 0.0001
1.183
LQ Q LL:R
1
—0.812
0.042 —19.136 0.0001
1.033
L f
1
2.544
0.22]. 11.535 0.0001
1.032
L I
I
-0.146
0.028 —5.117 0.0001
1.179
V &Z
11. LLD .Rrr DI 1’I
ditta
v p
v p v p v p
v p
r
LQ I
1.000
0.0002
0.0031 0.0214 0.0003
0.0174
2.495
0.0001
0.0063 0.0138 0.0001
0.7833
2.801
0.0003
0.0067 0.9285 0.0004
0.0005
10.662
0.0147
0.9266 0.0029 0.0253
0.1918
45.636
0.9847
0.0574 0.0334 0.9739
0.0071
- interv .1s oZ t ra ter esti t of ti xi 17 t e ’ 4 a
I.ferzr ii 19,20
R: ( 0.0384, 0.4096)
a: (—0.2321, —0.3031)
14b: ( 0.0792, 0.2977)
C: ( 1,9756, 3.1127)
d: (—0.2192, -0.0724)
bs *i rsd f Io ath Ct va1 s. u k* vartebi. emly.is
17

-------
the statisti 1 z si ti.bility a t of t1 e data sets. tbre crk
r th to be m to defir the hp t of stra .1. n variatior ard j. yj vert
i.D vjtr t i a t Ct values. In order to provide cxr exvative estimtes
for C t va1i in the ard iii guidar the aut s us i the a roadi
i11us at in Figure 3.
In Figure 3 the 99% fider interval at the 4 1 Iractivatia level
is cala.ilatel. First order kir ti are t that the thactiva-
ticii “lire” thrw t 1 at Ct — 0 arxl a Ct value al to the r 99%
tt.fi interval at 4 1 s of thactivaticr . Pa n be , the ir tiva—
tj 1ir mists of hi er Ct values than all of the an pr iict Ct
vali iati i 17, ia. , t of the Jarroil at al . , aid st of the
Hl 1ar at al. data nts. Oxsezvative Ct val , for a Apwifi level of
ir tivatia , n be thtair fx the inactivaticm 1ir presorib by the
disinf ti i cmttttcr . For the e p1e irdi ta in Fig e 3, the a o-
priate Ct for acthievin 99.9% inactivatia i1d be 105. This a çroacth
(as çtirm of first order kir tic ) also pzwid basis far estallishin
its for ee itia1 disinfectici st s as all w r the .
} pJaticv 17 s lied ueirq the a ye strategy, a safety f tar, to
dater li the ct va1 for 99.9 perixrzt 1n ivatia at 0.5 C ard 5 C In
the flzml R. 1 Ct va1u for t aratz above 5 C % S esti ta1
a irq a fa1d deoruass for every 10 C si all Niblar data s
rate S c 1. This era1 zircip1. is .çpartth by ff.
Jç il 4 rtfm of tia 17 to Iti a 8, iç to 9 — -
Z 15 k+— s a wc1al is tantial1y .. itLv. to (e.g., Cta at
9 are gc’ut thru. ‘ 4 . uatar than Cte at 6 d abc, t b ‘
gruatar than Ct at 7). At a 1I of 9, Luata1y f of the
1or * wid ft 1u of frss th1orir is still tuast. Oth data
18

-------
1.0000
0.1000
0.0100
0.0010
0.0001!
E

0.0000 -- .1 .. . .
0 20
OA
0 A
. . . .
Ct VALUES
FIGURE 3.
99% CONFIDENCE LEVELS USING HIBLER-
JARROLL EQUATION FOR CHLORINE • 2 mg/I;
PH . 6; TEMPERATURE 5°C
I
N
A
C
T
I
V
A
I
I
0
N
E
V
E
I
o CI-PRED.
ACTUAL Ct
99% CONF. INTERVAL
•0
I I I I I I I I I I I
40 60 80 100 120 140 160 180 200 220 240

-------
ii di te that t ax of 1 XI ree4ib i 1 (versa total free d 1oru r ir a1s
i1txW C1 ard 0c1) the Ct va1t ru Lira1 for inactivati of
G1ar ia ard Giax ia Ia±lia cysts de ease with ircreasirx çlf fr 7
9 16 } ver, with ir sasjrgg e1 , t? fracti of free d lormne existjrj
as t1 aker cidarTt ecies ( ) J eases. In of total free
düor z iñL1A1 (i.e., } Ci. ard 0C1) t Ct values r zir for In
activaticm of Giardia Ii aid Giardia la±1IA cysts i eeee with izx eaairq
FM frtn 7 to 9 b zt ra1.1y less than by a f tor of 2 at 1 t ti of
less than 5.0
Table 22 xes tk* Ct va1 1 alstsf in tkii final. 3fl i iz the
ifi a osd to t Ct vali fx t?a pz Ct values
In t prqcs 3 TB e 4 1y the RIbl.r data aid ir lt safety
factors. 2 ’
‘ & 22. RI WfTh 1’ uxiw A LE Cts
AT 99.9% CIIVJiflQ4 AND 5 C fl . . _ — AND F12 .L 3 lR
z itr sti 6 7 8
fL Final Final ht
3.
108
105
165
149
238
216
329
31.2
2
322
2.16
lU
165
269
343
371
35)
to M t . 1i*1zq 1 t*r c1es 1y ru irs t all
i mn hi t U.S. filt ar4’ dI.sin .ct to ot t
hsalth of ti ’ a.WtLww$ . 9. 1 4A b $ Gl1 1 tith Of *
of wt it eeJ in U.S. 9. 1 th1J.a
20

-------
cysts axe al u’ of the t resistant argeni to disinfecticzi by fres
thlorir . ‘s Office of t inkirz b t.er has the Ct cu t to
q. antify the x tivati of Q. la blia cysts by dlsthf& ticm. If a
utility n - re that a large en 4 Ct n be ixTtair to we
ate d i tu ticii t , dc ixq sits ific factors, it y
rct be r ired to lz taU fil atia . S1 d1* ly, the Ct n be
applied to filt ed syst for detarsinthg levels of pratectia .
In this paper , an e aticxi has b devel that n be ed to
predict Ct val for the inactivatkn of . l lia by frse dilorir based
the thteracti t of disinZ tant t ticm , t rature, I1, ar macti-
vaticn level. pers ters for this atia have bs derived fr a set
of aniral Infactivity data ard a ystati i data. The ati i be u to
predict Ct valuse for a tievirg 0.5 to 4 logs of 1nactivati , within t a-
ze rergse of 0.5 to 5 C, d loririe c ttia rar to 4 j/L, ard f
levels of 6 to 8. a iile the s r t ba at i{ valt a s 8, the
is still r idered a li h1e to levels tç to 9 for rseea
els md re. tiat sk is the effect of di ti ate ir esa of
C t ver ii .ivatiat levels. Wing 99% ifid& intervals at tla 4 log
1ziactjvat .ia levels w lying first oz Jth*tice to ss aid p nta a
ervative z 1sty s ategy for dsfinln C’t at variua levels of 1i i-
vaticm I b ed. This 5 1 its an alt tive to
r.gulat y teyy .via ly
2 a a1d 11J s to & Ju 1edgs ) . Pa a Piersat cd Pb.
Ibatledgs for siato in rliq this — ___
21

-------
t*tu2. to . J m )bff, fc i r1y of J . ria Wild, ) . ir1ey
ard ? . of the ziter Scie Orp ati Mr. vd.s
Black of the t iv zsity of Las V s, Nev a ard . tharl Haas of the
Iilir is Ir tibite of Ted l y f their reviw ard ti to i o ’e
the rz ipt.
22

-------
1. Nati 1 Pr ry ‘thkirq Water 1ati : PLltratia , Dsinfectj
Ttiztidity, Giar ia 1ait j . Vth aes, L icrEila , aid Hetarotr p ic
Sactarja. Final rule, 40 R parts 141 aid 142. Fed. . 54:124:27486
( . 3, 1987)
2. Nati a1 Pri ry .r 3cirrWater u1ati : Fil ati ,, Disthf ti ,
Turbidity, Giazdia L rI lia , Virus , Lø zii 11a , aid Heterotr t .jc
Bacteria. Pr z ed rule, 40 R parts 2.41. aid 142. Fed. . 52:212:
42718 (Nov. 3, 1987).
3. Noff, 3. C., NIn tivati of Mi thia1 q ta by a i 1 Disthfectartts’
V600/2-86—067.
4. Wat , H. Z. 1908. A rcte a t variatia of t rats of diainZectj
vith than in tk t ti of tk disinfaitant. 3. Hyg. 8:536-592.
5. Bez , G., than , S. L. aid Harris, E. K. 1964. Ditaltzatjcri of ai u-
organi by icd . Vol. I. D i of vjt 1. ‘ati of e taro-
vu by e1 rita1 i iz . Virol . 22:469-481.
6. Fair, G. K., Geyer, 3. C. aid 0 , 0. A. 1968. Water aid Waat at .sr
&iineerixz. Vol. 2 • Water p fi ti r aid at a ter ea t aid
1I5rv a .1 . J m Wiley aid Sa , Irc., N Y , NY .
7. Fair, G. K., M ris, 3. C. aid tharq, S. L. 1947. dyrsmic of tai
d 1orlzstici . . J flm :285-301.
8. FaIr, G. K., PL , is, 3. C., thaz , S. L., U Wail, aid az , R. P.
1941. mm *viar- of th1 ir a i ter disInZ tant. 3. )a. Water
‘brlc ). . 4Q:l051—1061.
9. 3. C., 1970. NDisIflf.taflt ( istry aid Bio ’ 4 1 1 .iviti”
In Pro s11z of - t tia 1 Spp-4*1 Ity ifrs i ____ _____
A ian Society of Civil Er ir rs, z Yak, NY.
10. C1ar , N. A., Barg, C., Yabl , P. W., aid a aiq, S. L., & ri &itailc
Vjri. In Wat : 9 viva1, aid ability”. ai tia sl
fe i ai Wat 11izti msmrth, I r, S ta r, 1962.
U. I ff, 3 . C., , S. W., aid Sthasf III, F. V. idztf im aid t
Of *t b z* Glardiaaia 0 , In Pr jrz of ths 1984 ‘1ty
wIzu 1 IJ rl iviai , z* 1984.
12. Janoll, S. L., Rhx , A. I .. aid ) , S. A. ‘ Ett * at th1 Ix ai
Giardia T ! i Cyst Vii.M tity. A 1ied aid bwir zai irital X1 4’ e w ,
1. 41, . 483—48, ? ary, 1981.
23

-------
13. Hibler, C.P., Har k, C. N., E rger, L. N., zyn, J. G. ard S ±y,
K. D. “Iri tivatia of Giar 1ia Cysts with Oilor at 0.5 C to 5.0 C.
A ri n ter rks As& iat La 1 earth F &ti , 6666 West Qiircy
Aven. , iver, 1.or 80235, 1987.
14. Clark, R. N. , E. J., ard Not!, J. C. “Analysis of Inactivati of
Giaz ia La 1ia by U .Lorir ”, Jo . a1 of wircx-z rital ir rixm
AS , Vol. 115, No. 1, F iruarj, 1989, ç. 80—90.
15. Ha.as, tharles W., aid Hillar, B. Stat.isti .l Analysis of C ta thiorine
Inactivati of Giardi.a La±Ua, Final P rt pr ar for U.S. A Off i
of ink z tar, Jar ary 6, 1988.
16. Ri , E. W., Not!, J. C. aid 5d aefer III, F. W. “I tivatim of Giardia
Cysts by Q &1crir ”, P i il aid E wirc nta1 Nior±iol V , Jan. 1982,
Vol. 43, No. 1, çp. 250—251.
17. .Ibi1L, A. J. “Cot Pr ts for the Inactivati Giax ia Cysts by th1or ,
C lora i , I ir , Oz , aid C üoride Di rb4m ” ‘ “idtte for p b1i ti
3. . Wetar W r ., 12/88.
18. aper, N. aid ith, H. (1981) 5c .r c d ittim, Arxlied R&iressia i Analysis ,
Wiley: Ne i l York.
19. Neter, 3. aid s&Pr n , W. (1974), A 1ie Linaar StatIstic ]. Pt,lels ,
Irwin: fl
20. l ley, D. A., ) .th, E. aid R. B. (1980), a siai D1a r t.ic ,
Wiley: N York.
21. U.S. thvir ta1 Prot tic* ) xy, Off i * of dzq tar, itaria
aid Staidards Divisi . waft Q.2idarce Narial for 1iar * with tl
Surf tar Tat t uJ ..r Tts for R b11c tar Syst , Narth 31,
1988.
24

-------
O8/O 1f 4 )
APPENDIX G—1
DETERMINING CHLORPJIINE INACTIVATION OF GIARD 1A
FOR THE SURFACE WATER TREATMENT RULE
Microbiological Treatment Branch
Risk Reduction Engineering Uboratory
and
Parasitology and Imuno logy Branch
Environmental Monitoring Systevis Laboratory
U.S. Environmental Protection Agency
26 West Martin Luther King Drive
Cincinnati, Ohio 45268

-------
2
TABLE OF CONTENTS
I. Materials..,.,.,,... ....................... . 3
II. eagents . ........,...... .. . 4
I II. Giardia rnuris Assay . 7
IV. Disinfection Procedures for Glardla . 10
V. Procedure for Determining Inactivation....................... ......12
V 1. 31 bi log ra phy 13
VII. Technical Contacts.. 14
Appendix
A. Use of the Hemocytorneter . . 15
8. PreparatIon and Loading of Chamber Slides. 20

-------
3
The Surface Water Treatment Rule requires 9.9% or greater removal/
inactivation of Glardia . The following protocol may be used to determine
the percentage of Giardla Inactivation obtained by a treatment plant
using chioramine dlsfnfect ion.
I. MATERIALS
A. Mater.ials for Disinfection
I. Stock chlorine solution
2. Stock ammonia solution
3. StIrring device
4. Incubator or water bath for temperatures below ambient
5. Water from treatment plant
6. Glardia muris cysts
7. Assorted glassware
8. Assorted pipettes
9. Reagents and Instruments for determining disinfectant residual
10. Sterile sodium thiosulfate solution
11. Vacuum filter device, for 47m diameter filters
12. 1.0 m pore size polycarbonate fIlters, 47 mn diameter
13. Vacuum source
14. Crushed Ice and ice bucket
15. Timer
B. Materials for Excystatlon
1. Exposed arid control Glardla muris cysts
2. Reducing solution
3. 0.1 M sodium bicarbonate
4. Trypsln-Tryode’s solution
5. 15 ml conical screw cap centrifuge tubes
6. Water bath, 37°C
7. Warm air Incubator or slide warming tray, 37°C
8. Aspirator flask
9. Vacuum source
10. Assorted pipettes
11. Vortex mixer
12. CentrIfuge with swinging bucket rotor
13. Chamber slides
L4. PI ase contrast microscope
15. DIfferential cell counter
16. T aer

-------
4
11. REAGENTS
A. Reducing Solution
Ingredient Amount
glutathione (reduced form) 0.2 g
L-cysteine—HC 1 0.2 g
1X Hanks’ balanced salt solution 20.0 ml
5 issolve the dry ingredients In the 1X Hanks’ balanced salt
solution and warm to 37°C before use In the experiment.
Prepare fresh, within 1 hour of use.
B. Sodium Bicarbonate Solution, 0.1 P1
In9redient Mount
Sodium bicarbonate 0.42 g
Dissolve the salt In 10 to 15 ml distilled water. Adjust
the volume to 50 ml with additional distilled water and
warm to 37°C before use in the experiment. Prepare fresh,
within 1 hour of use.
C. Sodium Bicarbonate Solution, 7.5%
ln9redient Amount
Sodium bicarbonate 7.5 g
Dissolve the sodium bicarbonate In 50 ml distilled water.
Adjust the volume to 100 ml with additional distifled
water. Store at room temperature.
0. Sodium Thiosulfate Solution, 10%
Ingredient Amount
Sodium thlosulfate 10.0 g
Dissolve the sodium thiosulfate in 50 ml distilled water.
Adjust the volume to 100 ml with additional distilled
water. Filter sterilize the solution through a 0.22 urn
porosity membrane or autoclave for 15 mInutes at 121°C.
Store at ro temperature.

-------
‘5
E. Tyrodes Solution, 20X
Ingredient Amount
had 160.0 g
KC1 4.0 g
CaC1 2 4.0 g
MgCl 6H O 2.0 g
aK 2 P0 4 R 2 O 1.0 g
Glucose 20.0 g
Dissolve the dry ingredients in the order listed in 750 ml
distilled water. adjust the volume to 1.0 liter with addi-
tional distilled water. If long term storage (up to I
year) Is desired, filter sterilize the solution through a
0.22 i m porosity membrane.
F. Tyrode’s Solution, l x
Ingredient Amount
20X Tyrode’s solution 5.0 ml
DIlute 5 ml of the 20X Tyrode’s solution to a final volume
of 100 ml with distilled water.
G. Trypsin-Tyrode’s Solution
Ingredient Amount
Trypsin, 1:100, U.S. &iocl emical Co. 0.50 g
NaHC O 3 0.15 g
lx Tyrode’s solution 100.00 ml
With continuous mixing on a stirplate, gradually add 100 ml
lx Tyrode’s solution to the dry ingredients. Continue
stirring until the dry Ingredients are completely dissolved.
Adjust the pH of the solution to 8.0 wIth 7.5% NaHCO 3 .
Chill the trypsln Tyrode’s solution to 4°C. NOTE: Trypsirt
lots must be tested for their excystation efficiency.
Prepare fresh, within 1 hour of use.
H. Polyoxyethylene Sorbltan Mortolaurate (Tween 20) Solution, 0.01%
(v/v)
Ingredient Amount
Tweeri 20 0.] ml
Add the Tween 20 to 1.0 lIter of distilled water. Mix
well.

-------
6
I. Vaspar
Ingredient
Paraffin 1 part
Petroleum jelly I part
Heat the two Ingredients In a boiling water bath until melt-
ing and mixing is complete.

-------
7
[ II. GIARDIA MURIS ASSAY
A. Cysts
Glardla muris Cysts may be available from commercial sources.
The cysts may be produced In Mongolian gerbils ( Meriones unguicu-
latus ) or in mice. Mus musculus , the laboratory mouse, CF-i.
BALSc, and C3H/he stF i s have been used to produce G. nuns
cysts. The method Is labor Intensive and requires a good animal
facility.
In order for the disinfection procedure to work properly, the G.
nuns cysts used must be of high quality. Evaluation of a cy t
suspension is a subjective procedure involving aspects of morpho-
logy and microbial contamination as well as excystment. A good
quality G. nuns Cyst preparation should exhibit the following:
1. ExamIne cyst stock suspension microscopically for the presence
of empty Cyst walls (ECu). Cyst suspensions containing equal
to or greater than 1% ECW should not be used for determining
inactivation at any required level. However, If a 99.9%
level of disinfection Inactivation Is required, the stock
cyst suspension must contain (0.1% ECW.
2. Excystation should be 90% or ;reater.
3. The cyst suspension should contain little or no detectable
microbial contamination.
4. GoodS. nuns cysts are phase bright with a defined cyst wall,
penitrophic space, and agranular cytoplasm. Cysts which are
phase dark, have no detectable peritrophic space, and have a
granular cytoplasm may be non-viable. There generally should
be no more than 4 to 5% phase dark cysts in the cyst prepara-
tion.
good G. nuns cyst preparations result when the following
gulderlnes are followed during cyst purification from feces:
a. t e feces collected over a period of 24 hours or less.
b. The Isolation of the cysts fr s the feces should be done
Ia ediately after the fecal material Is collected.
C. Initially, G. nuns cysts should be purified from the
fecal materf l by flotation using 1.0 P1 sucrose.
d. If the 6. munls cyst suspension contains an undesirable
density f contaminants after the first sucrose float,
further purification Is necessary. Two aethods for
further purification are suggested.
1) Cysts aay be reconcentrated over a layer of 0.85 N
sucrose In a 50 ml conical centrifuge tube. If this

-------
a
second exposure to sucrose is not done quickly, high
Cyst losses can occur due to their Increased bouyant
density In the hyperosrnotfc sucrose medium. The
cysts must be thoroughly washed free of the sucrose
Ininediately after collection of the Interface.
2) Cysts can be Separated from dissimilar sized contami-
nants by sedimentation at unit gravity, which will
not adversely affect cyst bouyant density, morphology,
or viability.
B. Maintenance of Cysts
1. Preparation of stock suspension
Determine the suspension density of the G. muris cyst prepara-
tion using a hemocytometer (see Appendix A). Mjust the Cyst
suspension density with distilled water to approxImately 3-5
* 1O cysts/mi.
2. Storage
Store cysts in distilled water in a refrigerator at 4°C.
Cysts should not be used for disinfection experiments if they
are more than 2 weeks old (from time of feces depusitlon).
C. Excystation Assay
A number of G. muris excystatlon procedures have been described In
the scientific literature (see Bibliography, Section VI). Any of
these procedures may be used provided 90% or greater excystatlon
of control, undisinfected G. muris cysts is obtained. The
following protocol is used to evaluate the suitability of cysts In
the stock suspension, and to determine excystatlon In control and
disinfected cysts.
1. For evaluating a cyst suspension or for running an unexposed
control, transfer 5 x i 5 G. muris cysts from the stock
preparation to a 15 ml conicil screw cap centrifuge tube. An
unexposed control should be processed at the same time as the
disinfectant exposed cysts.
2. educe the voltre of C. muris cyst suspension In each 15 ml
centrifuge tube to o.cmi or less by centrifugatlon at 400 x
g for 2 minutes. Aspirate and discard the supernatant to no
less than 0.2 ml above the pellet.
3. dd 5 .1 reducIng solution, prewarmed to 37C. to each tube.
4. Add 5 ml 0.1 N NaHCO3, prewarmed to 37’C. to each tube. NOTE:
Tightly close the caps to prevent the loss of C02. If the
co 2 escapes, excystatlon will not occur.
5. NIx the contents 0 f each tube by vortexing and place In
a 37°C water bath for 30 mInutes.

-------
9
6. Remove the tubes from the water bath and centrifuge each for
2 mInutes at 400 x g.
7. Aspirate and discard the supernatant to no less than 0.2 ml
above the pellet and resuspend the pellet In each tube In 10
ml trypsin-Tyrode’s solution chilled to 4°C.
8. CentrIfuge the tubes for 2 minutes at 400 x g.
9. spirate and discard the supernatant to no less than 0.2 ml
above the pellet.
10. d 0.3 ml trypsin-Tyrode’s solution, prewarmed to 37°C. to
each tube. Resuspend the G. muris cysts by low speed vortex-
Ing.
11. Prepare a chamber slide for each tube (see Appendix B).
12. Seal the coverslip on each chamber slide with i elted vaspar
and Incubate at 37°C for 30 mInutes In an incubator or on a
slide warmer.
13. After Incubation, place a chamber slide on the stage of an
upright phase contrast microscope. Focus on the slide with a
low poker cb ectIve. Use a total magnification of 400X or
more for the actual quantitation. NOTE: Be careful to keep
the objectives Out of the vaspar.
14. While scanning the slide and using a differential cell coun-
ter, enumerate the number of empty Cyst walls (ECW). partial-
ly excysted trophozoites (PET), and Intact cysts (IC) observed
(see Section V for a further description of these forms and
the method for calculating percentage excystatlon). If the
percentage excystatlon In the stock suspension Is not 90% or
greater, do not continue with the disinfection experiment.

-------
10
IV. DISINFECTION PROCEDURES FOR GIARDIA
A. The treatment plant water to be used should be the water influent
into the chloramlne disinfectIon unit process used in the plant.
If chioramine disinfection Is performed at more than one point In
the treatment process, e.g., prefiltratlon and postfiltration,
the procedure should simulate as closely as possible actual
treatment practice.
B. Prepare stock ammonia and chlorine solutions to be added to the
treatment plant water to achieve the same stoichiometric relation-
ship between chlorine and ammonia that Is used In the water
treatment plant. These solutions shou’d be concentrated enough
so that no more than 2 ml of each solution will be added to the
treatment plant water being disinfected.
C. Determine the Contact time by the methods described in the Surface
Water Treatment Rule and/or the associated C iidance Manual.
0. Rinse a 600 ml beaker with treatment plant water to remove any
extraneous material that may cause disinfectant demand. Then
add 400 ml treatment plant water to the beaker.
E. Nix the contents of the beaker short of producing a vortex in the
center and continue until the con lus1on of the experiment.
F. Equilibrate the 600 ml beaker and Its contents as li as the dis-
infectant reagents to the desired experimental temperature.
G. Mjust the stock G. muris cyst suspension with distilled water so
that the concentration is 2-5 x 1OD cysts/mi.
H. Add 0.5 ml of the adjusted cyst suspension to the contents of the
600 ml beaker.
1. P4d the disinfectant reagents to the beaker using the same rea-
gents, the same sequence of addition of reagents, and the same
time interval between addition of reagents that Is used in the
disinfection procedure In the treatment plant.
J. zst prior to the end of the exposure time, remove a sample ade-
quate for determination of the disinfectant residual concentra-
tion. tat-methods prescribed In the Surface Water Treatment Rule
for th. determination of combined chlorine. This residual should
be the same (x2O%) as residual present In the treatment plant
operation.
K. At the end of the exposure time, add 1.0 m l 101 sodhr thiosulfate
solution to the contents of the 600 ml beaker.
L. Concentrate the G. curls cysts In the beaker by filtering the
entire contents t rough a 1.0 c porosity 47 m diameter polycar-
bonate filter.

-------
U
Ii. Place the filter, cyst side up, on the side of a 150 ml beaker.
Add 10 ml 0.01% Tween 20 solutIon to the beaker. Using a Pasteur
pipette, wash the 6. muris cysts from the surface of the filter
by aspirating and expelling the 0.01% Tween 20 solutIon over the
surface of the filter.
N. Transfer the contents of the 150 ml beaker to an appropriately
labeled 15 ml screw cap conical centrifuge tube.
0. keep the tube on crushed ice until the excystation assay is
performed (see Section I II, C) on the disinfectant exposed cysts
and on an unexposed control preparation obtained from the stock
cyst suspension.

-------
12
V. PROCEDURE FOR DETERMINING INACTIVATIOM
A. Giardla muris Excystatlon Quantitation Procedure
The percentage excystatlon is calculated using the following for-
mula:
excystation = tC i + PET x lao,
ECW s PET + IC
where ECW Is the number of empty cyst walls,
PET Is the number of partially excysted trophozoites, and
IC Is the number of intact cysts.
An ECW Is defined as a cyst wall which Is open at one end and Is
completely devoid of a trophozolte. A PET Is a cyst which has
started the excystatlon process and progressed to the point where
the trophozoite has either started to emerge or has completely
emerged and Is still attached to the cyst wall. An 1C is a
trophozofte which Is completely surrounded with a Cyst wall
showing no evidence of emergence. For the control , generally 100
forms are counted to determine the percent excystatlon.
The number of cysts that must be observed and classiffed (ECW,
PET, IC) in the disinfected sample is dependent on the level of
inactivation desired and on the excystatlon percentage obtained
in the control.
For 0.5, 1 and 2 log 10 reductions, (68%, 90% and 99% inactI-
vation, respectively), the minimum number of cysts to be
observed and classified Is determined by dividing 100 by the
percentage excystatlon (expressed as a decimal) obtained in
the control.
For a 3 10910 reduction (99,9% InactivatIon) the minimum
number of cysts to be observed and classified is determined
by dividing 1.000 by the percentage excystatlon (expressed
as a decimal) obtained In the control.
8. Oeter.Inlnj Inactivation
The msunt of Inactivation Is determined by comparing the percent-
age excystatlon of the exposed Cyst preparation to the percentage
excystatlon in the control preparation using the following for-
mula:
S Inactivation s 100% — [ (exposed S excystedlcontrol S excysted) x 100]
If the percentage excystation In the exposed preparation Is zero,
i.e., only IC (no ECW or PET) are observed and counted, use <1 as
the value for exposed S excysted in the formula for calculating
S inactivation.

-------
13
VI. BIBLiOGRAPHY
American Public Health Association; American Water Works Association;
Water Polutlon Control Federation. Standard Methods for the Examina-
tion of Water and Wastewater , 16th ed. (1985).
Belosevic, N. & G.M. Faubert. Glardia nuns : correlation between
oral dosage, course of infection, and trophozolte distribution in the
mouse small intestine. Exp. Parasitol., 56:93 (1983).
Erlandsen, L.S. and E.A. Meyer. Glardia and Giardiasis. Plenum
Press, New York, (1984).
Faubert 1 G.M. et al. Comparative studies on the pattern of infec-
tion with Giardia spp. in Mongolian gerbils. J. Parasltol., 69:802
(1983).
Feely, D.E. A simplifed method for in vitro excystatlon of Giardla
nuns . 3. Parasltol.. 72:474—475 (i9 ).
Feely, D.E. Induction of excystation of Giardia nuns by Co 2 . 62nd
Annual Meeting of the M erican Society of ParasitoTogists, Lincoln,
Nebraska 1 Abstract No. 91 (1987).
Gonzalez—Castro, J., Bermejc—Vfcedo , M.T. and Palacios—Gonzalez, F.
Desenquistamlento y cultivo de Giardla nuns . Rev. Iber. Parasitol.,
46:21-25 (1986).
Melvin 1 D.M. and MM. Brooke. Laboratory Procedures for the Diagnosis
of Intestinal Parasites. 3rd ed., HHS Publication No. (CDC) 82—8282
(1982).
Miale, J.B. Laboratory Medicine Hematology, 3rd ed. C. V. Mosby
Company, St. Louis, MissourI (1967).
Roberts-Thomson, 1.C. et al. Giardlasis In the mouse: an animal
model. Gastroenterol., 71:57 (1976).
Sauch, J,F. Purification of Gierdia nuns cysts by velocity sedi-
mentation, Apph Environ. PlIcrobiol., 48:454 (1984).
Sauch, J ,F. A new method for excystatlon of Glardla . Advances In
Giardla R•sssrch. University of Calgary, Calgary, Canada (In Press).
Schaefer, III, .W., Rice, E.W., & Hoff, J.C. Factors promoting
In vitro excystatlon of Glardla muris cysts. Trans. Roy. Soc. Irop.
Rid. {yg., 78:795 (1984).

-------
14
VIZ. TECHNICAL CONTACTS :
A. Eugene W. Rice
Microbiological Treatment Branch
Risk Reduction Engineering Laboratory
U.S. Environmental Protection Agency
26 West Martin Luther King Drive
Cincinnati, Ohio 45268
Phone: (513) 569-7233
8. Frank W. Schaefer, II I
Parasitology and Immunology Branch
Environmental flonitoring Systems Laboratory
U.S. Environmental Protection Agency
26 West Martin Luther King Drive
Cincinnati, Ohio 45269
Phone: (513) 569-7222

-------
15
Appendix A: Use of the Ilemocytometer
Suspension Density Determination Using the Improved tleubauer (Bright-line)
Hemocytometer
The henocytometer consists of two chambers separated by a transverse
trench and bordered bilaterally by longitudinal trenches. Each chamber
is ruled and consists of nine squares, each 1 x 1 x 0.1 mm with a
volume of 0.1 mm 3 . Each square mm is bordered by a triple line. The
center line of the three is the boundary line of the square. (See
Figure 1).
According to the U. S. Bureau of Standards’ requirements, the cover
glass must be free of visible defects and must be optically plane on
both sides within plus or minus 0.002 m m. ONLY HEM0CYTONETER COVER
GLASSES MAY BE USED. ORDINARY COVER GLASSES AND SCRkTCHED HEMOCYTOMETERS
ARE UNACCEPTABLE , as they introduce errors into the vo l ume relationships.
The suspension to be counted must be evenly distributed and free of
large debris 1 so that the chamber floods properly. The suspension to be
counted should contain 0.011 Tween 20 solutton to prevent Giardia cysts
from sticking and causing improper hemocytometer chamber flooding. Cyst
suspensions should be adjusted so that there are a total of 60 to 100 cysts
in the four corner counting squares. Counts are statistically accurate
in this ranye. If the suspension is too numerous to be counted, then it
must be diluted sufficiently to bring it into this range. In some cases,
the suspension will be too dilute after concentration to give a statisti-
cally reliable count In the 60—100 cyst range. There is nothing that can
be done about this situation other than to record the result as question-
able.
To use the hemocytonteter:
1. DIlute or concentrate the suspension as required.
2. Apply a clean cover glass to the henocytoineter and load the
hemocytometer chamber with 9—10 p1 of vortexed suspension per
chamber. If this operation has been properly executed, the
liquid should amply fill the entire chamber without bubbles or
overflowing Into the surrounding moats. Repeat this step with a
clean, dry hemocytoneter and cover glass 1 if loading has been
Incorrectly done. See step (12) below for the hemocytometer
cl cant nrprocsure.
3. riot attempt to adjust the cover glass, apply clips, or In any
way disturb the chamber after it has been filled. Allow the
Giardia cysts to settle 3D to 60 seconds before starting the
count.
4. The Giardia cysts may be counted using a magnification 200-600X.
S. Itove the chamber s the ruled area Is centered underneath It.
6. iZnj t loi r : ofl :: t i 0 v t r t %P Ji

-------
16
7. Focus up from the coverslip until the hemocytoneter ruling
appears.
8. At each of the four corners of the chamber is a 1 rmn 2 divided
into 16 squares in which Ofardia cysts are to be counted (see
Figure 1). Beginning with the top row of four squares, count
with a hand tally counter in the directions indicated in Figure
2. Avoid counting Giardia cysts twice by counting only those
touching the top and left boundary lines and none of those touch-
ing the lower and right boundary lines. Count each square mm in
this fashion.
9. The formula for determining the number of Giardia cysts per ml
suspension is:
A of cysts counted 10 dilution factor 1 ,000 mu ?
Hofsq.nvncounted r lml
A cysts/m I
10. Record the result on a data sheet similar to that shown in
Figure 3.
11. A total of six different hemocytonieter chambers must be loaded,
counted, and then averag2d for each Giardla cyst suspension to
achieve optimal counting accuracy.
12. After each use, the hemocytometer and coverslip must be cleaned
immediately to prevent the cysts and debris from drying on it.
Since this apparatus is precisely machined, abrasives cannot be
used to clean it as they will disturb the flooding and volume
relationships.
a. Rinse the henocytometer and cover glass first with tap
water, then 70% ethanol, and finally with acetone.
b. Dry and polish the hemocytometer chamber and cover glass
with lens paper. Store it in a secure place.
13. A nrber of factors are known to introduce errors into hemocyto-
meter counts. These include:
a. Inadequate suspension mixing before flooding the chamber.
b. Irregu lar filling of the chamber, trapped air bubbles,
dust, or oil on the chamber or coverslip.
c. Chamber coversllp not flat.
d. Inaccurately ruled chamber.
e. The eniseration procedure. Too many or too few Giardia
cysts per square, skipping or recounting some Giardiatists.

-------
17
f. Total number of Glardia cysts counted is too low to
give statistical confidence In result.
9. Error In recording tally.
h, Calculation error; failure to consider dih tion factor,
or area counted.
1. Inadequate cleaning and reqnoval of cysts from the previous
Count.
j,. Allowing fllled chamber to sit too long so that chamber sus-
pension dries and concentrates.

-------
lm
-
:
••
£
•
‘
18
FIgure 1. I4emocytometer platform ruling. Squares 1, 2, 3, and 4 are
used to count Giardla cysts. (From MIale, 1967)
a
a
0
-.—
-
I .—
-;
L
__
.
v—
—•
jH
)


.
r
t_
.
•_-S .-
•0
I
*
.,

.•___j
I
)
—
—
-
Figure 2. P nner of counting Glardla cysts In 1 square —. Dark cysts
are counted and light cysts are omitted. (After NIale, 1967)

-------
1g
Dite
Per s
Counting
Ceu t
I
0 Cells
Courted
g 2
Counted
Dlluttøn
Factor
0
.1
R ir
I
-___
2
3
4
S
6
7
B
9
10
11
12
13
14
IS
16
17
16
1 5
to
•• cysts/mi • lot cysts counted 10 dilution factor i,ooo
— m1
Figure 3. Nemocytoceter Ots Sheet for Gludla Cysts

-------
Appendix B. Preparation and Loading of Excystation Chac ber Slides
1. UsIng tape which Is sticky on both sides, cut strips approximately 12
x 3 mm.
2. pp1y a strip of the tape to one side of a 22 x 22 mm coversltp.
3. Apply a second strip of tape to the opposite edge but same side of
the coversllp.
4. HandlIng the coversllp by the edges only, attach the co ersl1p to the
center of a 3 x 1 Inch glass slide by placing the taped sides of the
coverslip down along the long edge of the glass slide.
5. hake sure the coversllp Is securely attached to the slide by lightly
pressing down on the edges of the coversllp with your fingers. Care
should be taken to keep finger prints off the center of the coversllp.
6. To load the chamber slide, place a Pasteur or microliter pipette
containing at least 0.2 ml of the Glardia cyst suspension about 2 m
from an untaped edge of the coverslip. Slowly allow the cyst suspen-
sion to flow toward the coverslip. As It touches the coversllp it
will be wicked or drawn rapidly under the co erslIp by adhesive forces.
Only expell enough of the Cyst suspension to completely fill the
chamber formed by the tape, slide, and coversllp.
7. Wipe away any excess cyst suspension which Is not under the coverslip
with an absorbant paper towel, but be careful not to pull Cyst
suspension from under the coversllp.
8. Seal all sides of the coversllp with vaspar to prevent
drying out during the Incubation.
the slide from
NOTE: Prepared excystatlon chamber slides may be comerclally avail-
able from Spiral Systems, Inc., 6740 Clough Pike, Cincinnati,
Ohio 452 , (513) 231—1211 or 232-3122, or from other sources.
Figure 1. Excystatlon Chamber Slide

-------
O8/ I,S
APPENDIX G-2
DETERMINING CHLORAMINE INACTIVATION OF VIRUS
FOR THE SURFACE WATER TREATMENT RULE
Microbiological Treatment Branch
Risk Reduction Engineering Laboratory
and
Parasitology and Imunology Branch
Environmental Monitoring Systems Laboratory
U.S. Environmental Protection Agency
26 West Martin Luther King Drive
Cincinnati, Ohio 45268

-------
2
TABLE OF CONTENTS
1. Materia ls....,.......... .....•....
(I. eagents and Media ... ...... 4
I It. M 52 Bacteriophage Assay ....... . 6
IV. Disinfection Procedure.. . ............ ... . .. .8
V. Procedure for Determining Inactivation . 9
Vt. Aibliography 10
V I I . Te C Pin I cal Contacts , • • •4 • . . . 11

-------
3
The Surface Water Treatment Ru e requires 99.99% or greater removal/
inactivation of viruses. The following protocol may be used to determine
the percentage of virus inactivation obtained by a treatment plant usinç
chloraniine disinfection.
I. MATERIALS
A. Materials for Disinfection
1. Stock chlorine solution
2. Stock ammonia solution
3. Stirring device
4. Incubator or water bath for less than ambient temperature
5. Water from treatment plant
6. MS2 bacteriophage
7. Assorted glassware
8. Assorted pipettes
9. Aqueous 1 sterile sodium thiosulfate solution
10. Refrigerator
11. Vortex mixer
12. Timer
Materials for MS2 Assay
1. MS2 bacteriophage and Its Escherlchla coll host
2. Assorted glassware
3. Assorted pipettes
4. Incubator, 37°C
5. Refrigerator
6. Petri dishes, 100 x 15 rr, sterile
7. Vortex mixer
8. Water bath, 45°C
9. Sterile rubber spatula
10. LOlA, disodiwn salt
11. Lysozyme crystallized from egg white
12. Centrifuge with swinging bucket rotor

-------
4
II. REAGENTS AND MEDtA
A. Tryptone—Yeast Extract (rYE) Broth
Ingredient Amount
Bacto tryptone 10.0 g
Yeast extract 1.0 g
Glucose 1.0 g
NaC 1 8.0 g
1.0 N CaCI 2 2.0 ml
Dissolve In distilled water to a total volume of 1.0 lIter,
then add 0.3 ml of 6.0 N NaOH, This medium should be steri-
lized either by autoclaving for 15 mInutes at 121°C or
filtration through a 0.22 urn porosity membrane and then
stored at approximately 4°C. It Is used in preparing
bacterial host suspensions for viral assays.
B. Tryptone-Yeast Extract (lYE) Agar
Ingredient Mount
lYE broth 1.0 liter
Agar 15.0 g
The agar should be added to the broth prior to steriliza-
tion. The medium should be sterilized by autoclaving for
15 mInutes at 121°C. This medium Is used to prepare slant
tubes for maintenance of bacterial stock cultures. The
prepared slant tubes should be stored at approximately 4°C.
C. Bottom Agar for Bacteriophage Assay
Ingredient Amount
Bacto tryptone 10.0
Agar 15.0 g
NaCI 2.5 g
KC1 2.5 g
1.0 M CaC1 2 1.0 ml
Dissolve the ingredients In distilled ter to a total
volume of 1 liter. The medli.an should be sterilized by
autoclaving for 15 mInutes at 121°C. After autoclaving and
cooling, store at 4°C. I rediately prior to use, liquefy
the med1i by heating, Add approximately 15 ml of llque-
fled agar Into each Petri dish. This bottom layer serves
as an anchoring substrate for the top agar layer.

-------
5
0. Top Agar for Bacteriophage Assay
gred1ent Amount
Bacto tryptone 10.0 g
Agar 8.0 g
NaCi 8.0 g
Yeast extract i.o g
Glucose i.o g
1.0 4 CaC1 2 1.0 ml
Dissolve the ingredients In distilled water to a total
volume of 1 lIter. This medium should be sterilized by
autoclaving 15 minutes at 121°C. After cooling, store at
4°C until needed in bacteriophage assays. Imedlately
prior to use in assays, liquefy the medium by heating and
then cool to and maintain at a temperature of 45°C.
E. Salt Diluent for Bacteriophage Assay
Ingredient Amount
ha 1 8.5 g
1.0 N Cad 2 2.0 ml
Dissolve In distilled water to a total volume of I liter.
Tt 1s diluent should be sterilized either by autoclaving
for 15 minutes at 121°C or filtration through a 0.22 im
porosity membrane. Store at room temperature.
F. CaC1 2 , 1.0 N
Ingredient Amount
Ca l 2 11.1 g
Dissolve In distilled water to a total volume of 100 ml.
Autoclave 15 minutes at 121°C or filter sterilize the
solution through a 0.22 pm porosity membrane. Store at
room temperature.
G. Sodium Thlosulfate, 1%
£nqredient M ount
5odlum thlosulfate 1.0 g
Dissolve the sodium thiosulfate In 50 ml distilled water.
Adjust the volume to 100 ml with additional distilled
water. Filter sterilize the solution through a 0.22 pm
porosity menbrane or autoclave 15 minutes at 121’C. Store
at room temperature.

-------
S
III. M52 BACTERIOPHAGE ASSAY
A, Microorganisms
1. 1452 bacteriophage: catalog number 15597-Bi, American Type
Culture Collection, 12301 Parkiawn Drive, Rockville, MD 20852
2. Bacterial host: Eschertchla coil , catalog number 15597,
American Type Culture Collection.
B. Growth and Maintenance of Microorganisms
1. Preparation of bacterial host stock cultures
Inoculate host bacteria onto TIE agar slant tubes, incubate
24 hours at 37°C to allow bacterial growth 1 and then refriger-
ate at 4°C. At monthly intervals the cultured bacterial
hosts should be transferred to a new TIE agar slant.
2. Preparation of bacteriophage stock suspension
Melt top agar and maintain at 45’C. Add 3 ml of the agar to
a 13 x ZOO m test tube contained in a rack In a 45°C water
bath. Add 0.5 to 1.0 ml of the bacteriophage suspension
diluted so that the most bacterial ‘lawn ’ will show nearly
complete lysis after overnight incubation. Add 0.1 to 0.2 ml
of a TIE broth culture of the host bacteria that has been
incubated overnight. Mix gently and pour the contents on the
surface of bottom agar contained in a Petri dish that has
been prepared previously. Rock the Petri dish to spread the
added material evenly over the agar surface. After the top
agar solidifies (about 15 minutes), invert the Petri dish
and incubate overnight at 37°C. Repeat the above procedure
so that a minimum of S but no more than 10 Petri dishes are
prepared.
Following this incubation and using a sterile rubber spatula,
gently scrape the top and bottom agar layers into a large
beaker. Md to this pool of agar layers an amount of TIE
broth sufficient to yield a total volume of 80 ml. To this
mixture add 0.4 g of (OTA (disodir salt) and 0.052 g of
Ipozj.e (crystallized from egg white). Incubate this mixture
atroou.taperature for 2 hours with continuous mixing. Then
catrifuge the mixture for 15 minutes at 3,000 x g. Carefully
reova the upper fluid layer. This fluid layer constitutes a
viral stock suspension for use in subsequent testing and
essays. The viral stock suspension may be divided into
aliquots and stored either frozen or at Vt.
C. Performance of Bacteriophage Assay
A two-week supply of Petri dishes uy be poured with bottom agar
ahead of time and refrigerated inverted at 4°C. If stored in a
refrigerator, allow agar plates to equilibrate to room tsperature

-------
7
before use. Eighteen hours prior to beginning a bacteriophage
assay, prepare a bacterial host suspension by inoculating 5 ml of
T n broth with a small amount of bacteria taken directly from a
slant tube culture. Incubate the broth containing this bacterial
inoculum overnight (approximately 18 hours) at 37°C invnediately
prior to use in bacteriophage assays as described below. This
type of broth culture should be prepared freshly for each day’s
bacteriophage assays. If necessary, a volume greater than S ml
can be prepared in a similar manner.
On the day of assay, melt a sufficient amount of top agar and
maintain at 45°C in a water bath. Place test tubes (13 * 100 mm)
in a rack in the same water bath and allow to warm, then add 3 ml
of top agar to each tube. Inoculate the test tubes containing
top agar with the bacteriophage samples (0.5 to 1.0 ml of the
sample/tube) plus 0.1 to 0.2 ml of the overnight bacterial host
suspension. Dilute the bacteriophage samples from io1 to io-’
in salt diluent prior to Inoculation and assay each dilution in
triplicate. In addition, assay the uninoculated salt diluent as
a negative control. Agitate the test tubes containing top agar.
bacteriophage inoculum, and bacterial host suspension gently on a
vortex mixer, and pour the contents of each onto a hardened
bottom agar layer contained In an appropriately numbered dish.
Quickly rock the Petri dishes to spread the added material evenly 1
and place on a flat surface at room tsparature mhile the agar
present in the added material solidifies (approximately 15 min-
utes). Invert and incubate the dishes at 31°C overnight (approxi-
mately 18 hours). The focal areas of viral infection which
develop during this incubation are referred to as plaques’ and,
if possible, should be enumerated inrediatly after the incubation.
If necessary, the incubated Petri dishes can be refrigerated at
4°C overnight prior to plaque enumeration. As a general rule,
count only those plates that contain between 20 and 200 plaques.

-------
IV. DISINFECTION pqocEDuRE
A. The treatment plant water to be used should be the water influent
Into the chloranthe disinfection unit process used in the plant.
If chloramine disinfection is performed at more than one point in
the treatment process, e.g. prefiltration and postfiltration. the
procedure should simulate as closely as possible actual treatment
practice.
B. Prepare stock ammonia and chlorine solutions to be added to the
treatment plant water to achieve the same stoichiometriC relation-
ship between chlorine and ammonia that is used in the water
treatment plant. These solutions should be concentrated enough
so that no more than 2 ml of each solution will be added to the
treatment plant water being disinfected.
C. Determine the contact time by the methods described in the Surface
Water Treatment Rule and/or the associated Gaidance Manual.
D. Rinse two 600 ml beakers with treatment plant water to remove any
extraneous material that may cause disinfectant demand. Then add
400 ml treatment plant water to the beaker. The first beaker
will be seeded with 1152 before the contents are chioraminated.
The second beaker will be an indigenous virus control and will
b3 chloraminated without addition of extraneous phage.
E. Mix the contents of the beaker short of producing a vortex in the
center and continue until the conclusion of the experiment.
F. Equilibrate the 600 ml beakers and their contents as well as the
disinfectant reagents to the desired experimental temperature.
G. Dilute the stock 1152 bacteriophage so that the bacteriophage con-
centration is I to 5 x 108 PFIJ/ml.
H. Md 1.0 ml of the diluted 1 1S2 bacteriophage to the contents of the
first 600 ml beaker.
I. Remove a 10 ml sample from the contents of the first beaker after
2 minutes of mixing. Assay the MS2 bacteriophage concentration
In this sample within 4 hours and record the results as PFU/ml.
This value is the initial M52 concentration.
4. ovs a 10 ml sample from the contents of the second beaker
after 2 minutes of mixing. Assay the indigenous bacteriophage
concentration in this sample within 4 hours (at the same time as
you assay the sample from the first beaker) and record the
results as PFU/e l. This value is the Initial unseeded concentra-
tion.
K. Md the disinfectant reaqents to the contents of both beakers
using the same sequence, time, and concentrations as are used in
the actual treathent plant operations.

-------
I.. Just prior to the end of the contact tine, remove a volume of sam-
ple adequate for determination of the disinfectant residual con-
centration from both beakers. Use methods prescribed In the
Surface Water Treatment Rule for the determination of combined
chlorine, This residual should be the same (±20%) as the
residual present in the treatment plant operation.
N. At the end of the exposure time, remove a 10 ml sample from the
first 600 ml beaker and neutralize with 0.25 ml of 1.0% aqueous,
sterile sodir thiosulfate. Assay for the $52 bacteriophage
survivors and record the results as PFIjfml. This value is the
exposed $52 concentration.
N. At the end of the exposure time, remove a 10 ml sample from the
second 600 ml beaker and neutralize with 0.25 ml of 1.0% aqueous,
sterile sodium thiosulfate. Assay for the indigenous bacterio-
phage survivors and record the results as PFU/nl. This value is
the exposed unseeded concentration.
1. PROCEDURE FOR DETERMINING INACTIVATION
A. Calculation of Percentage Inactivation -
Use the following formula to calculate the percent inactivation
of $52:
1. % inactivation • 100% . [ (exposed $52/initial 1152) x 100]
Using values from Section IV steps I, J, Ii and N calculate initial
$52 and exposed $52 as follows:
2. InItial $52 (PFU/ml) a —
3. Exposed $52 (PFUfml) a -
If the number of PF1J/ml in exposed $52 is zero, I.e., no plaques
are produced after assay of undiluted and diluted samples, use <1
PFU/ml as the value in the above formula.
8, Comparison of Percentage Inactivation to Log 10 of Inactivation
68% inscUvation is equivalent to 0.5 log 1 inactivation
90% inactivation is equivalent to 1 log inactivation
99% InactIvation is equivalent to 2 logio inactivation
99.9% Inactivation is equivalent to 3 log inactivation

-------
10
V I. BIBUOGRAPHY
Adams, N.H. Bacteriophages. Intersclence Publishers, New York (1959).
Aniericart Public Health Association; American Water Works Association;
Water Pollution Control Federation. Standard Methods for the Examina-
tion of Water and Wastewater , 16th ed. (1985).
Grabow, W.O.K. et al. Inactivation of hepatitus A virus, other enter-
Ic viruses and Indicator organisms In water by chlorination. Water
Sd. Technol., 17:657 (1985)
Jacangelo. .3.0.; OlivIeri, V.P.; Kawata, K. P chan1sm of Inactiva-
tion of microorganisms by combined chlorine. AWWARF Rept., Denver,
CO (1987).
Safe Drinking Water Cormiilttee. The disinfection of drinking water.
In: Drinking Water and Health , National Academy Press, Washington,
D.C.. 2:5 (19B0).
Shah, P. & McCamlsh, .3. Relative resistance of pollovirus I and coil-
phages f 2 and 12 In water. Appl. Microblol. 24:658 (1972).
U.S. Environmental Protection Agency. Guidance Manual for Compliance
with the Filtration and Disinfection Requirements for Public Water
Systems Using Surface Water Sources. Appendix 6. U.S. EPA, Office
of Water, Criteria arid Standards Division, Washington, D.C. (1988).
Ward, N.R.; Wolfe, R.L.; & Olson, B.H. tffect of pH, applIcation
technique, and chlorine-to-nitrogen ratio on disinfectant activity of
inorganic chloramlnes with pure culture bacteria. Appi. Environ.
Microblol., 48:508 (1984).

-------
1 1
V I I. TECHNICAL CONTACTS :
A. DonaU Berman
MicrobIologIcal Treatment Branch
Risk Reduction Engineering Laboratory
U.S. Environmentat Protection Agency
26 West Martin Luther King Drive
Cincinnati, Ohio 45268
Phone: (513) 569-1235
B. christon J. Hurst
Microbiological treatment Branch
Risk Reduction Engineering Laboratory
U.S. Environmental Protection Agency
26 West Martin Luther King Drive
Cincinnati, Ohio 45268
Phone: (513) 569—7331

-------
G.3 DETERMINING CHLORINE DIOXIDE INACTIVATION
OF GIARDIA CYSTS AND VIRUS
Giirdia Cysts
The basis for the chlorine dioxide CT values for Giardia cysts in
the Guidance Manual is given in Appendix F.1.2. The CT values are based
on data collected mainly at pH 7. Very little data was available at other
pHs. A review of data from Hoff (1986) indicates that the disinfection
efficiency of chlorine dioxide for bacteria and viruses increases
approximately 2 to 3 fold as pH increases from 7 to 9. Data on which the
CT values in the SWTR are based indicate that at 25 C. . nuns cyst
inactivation CTs were approximately 2 fold higher at pH 7 than at pH 9
(Leahy, 1985). In addition, the data also Indicate that chlorine dioxide
efficiency increases as disinfectant concentration increases within the
range studied.
Because the data on effects of chlorine dioxide concentration and
water pH on Giardia cyst inactivation efficiency were very limited, they
were not considered in calculating the Giardia cyst CT values in Appendix
E. However 4 the data suggest that site specific conditions, i.e. water
pH and disinfectant concentration, can have significant effects on
chlorine dioxide effectiveness. Therefore, the option of allowing the
Primacy Agency to consider the use of lower CT values by Individual
systems has been provided.
This approval should be based on acceptable experimental data
provided by the system. The data should be collected using the protocol
provided in Appendix G-1 for detenoining Giardia cyst Inactivation by
chioramine with appropriate changes in Section IV A, B, I end J to reflect
the use of chlorine dioxide rather than chioramines. This procedure can
be used for any disinfectant which can be prepared in an aqueous solution
and Is stable over the course of the testing. To do this, chloramine
should be replaced with the test disinfectant in the above noted sections.
G.3 - 1

-------
Virus
The basis for the chlorine dioxide CT values for virus in Appendix
F.2.2 consists of limited data from Sobsey (1988). Because the pH 9 data
available were very limited, the CT values are based on the pH 6 data with
a safety factor of 2 applied. As indicated previously, review of data
from a number of studies (Hoff, 1986) shows that chlorine dioxide
efficiency increases 2 to 3 fold as pH increases from 7 to 9.
Because the virus CT values for chlorine dioxide are very conserva-
tive and most systems operate at water plis higher than those on which the
CT values are based, the option of allowing the Primacy Agency to consider
the use of lower CT values has been provided.
This approval should be based on acceptable experimental data
provided by the system. The data should be collected using the protocol
provided in Appendix 6.2 with appropriate changes in Sections 1 A,1 and
2 and IV A, B, D, K, and L to ref le t the use of chlorine dioxide rather
than chiorainines. This procedure can be used for any disinfectant which
can be prepared in an aqueous solution and is stable over the course of
the testing. To do this, chioramine should be replaced with the test
disinfectant in the above noted sections.
REFERENCES
Hoff, J.C. Inactivation of Microbial Agents By Chemical Disinfectant’s,
EPA/600/52-86/067, U.S. Environmental Protection Agency, Water Engineering
Research Laboratory, Cincinnati, Ohio, September, 1986.
Leahy, J.G. Inactivation of Giardia Muri Cysts by Chlorine and Chlorine
Dioxide. Thesis, Department of Civil Engineering, Ohio State University,
1985.
Sobsey, M.D. Detection and Chlorine Disinfection of Hepatitis A Virus in
Water. C 13D24, EPA Quarterly Report, Dec. 1988.
6.3 - 2

-------
G.4 DETERMININIG OZONE INACTIVATION OF GIARDIA CYSTS AND VIRUS
G.4.I BACKGROUND
The basis for the ozone CT values are given in Appendices F.1.2
( Giardia cysts) and F.2.4 (Virus). As indicated, both sets of CT values
are based on limited data and because of this, the values established are
conservative and employ large safety factors. In addition, the difference
between how laboratory experiments were used to develop the CT values and
how ozone is used in water treatment presents a problem with translating
the data for field use. The laboratory studies were conducted using
steady state ozone concentrations with ozone continually added during the
contact period. In contrast, steady state ozone concentrations are mot
maintained in field use. Also, the effectiveness of ozone contactors used
in field applications may gary from each other and from the mixing
efficiencies applied in the laboratory experiments used to establish the
CT values.
The net effect of all of these differences limits the applicability
of the CT values in the SWTR and Guidance Manual to individual systems.
Therefore, the option of allowing the Primacy Agency to consider the use
of lower CT values by individual systems has been provided.
This approval should be based on acceptable experimental data
provided by the system. In general, the procedures provided in Appendix
G.1 for determining Giardia cyst inactivation and Appendix G.2 for
determining virus inactivation can be used. However 4 unlike chloramines
ozone is not a stable disinfectant. Because of ozone’s rapid dissipation,
a pilot study may be used in lieu of the batch system to demonstrate the
disinfection efficiency for a particular system. General considerations
for conducting pilot studies to demonstrate the disinfection ability of
ozone or any other unstable disinfectant are ern.aerated below.
G.4.2 General considerations for Pilot Test
A. All microorganisms, reagents and media are prepared as in-
dicated In sections 6.1 for Glardia and 6.2 tar virus.
B. The disinfectant should be prepared, measured and added to the
test water as it weuld be added to the water at the water
treatment plant.
G.4 - 1

-------
C. Specific reactor design should be a function of the disinfec-
tant and reflect flow the disinfectant is added at the water
treatment plant. Provisions should be made to determine
concentration of disinfectant and microbial survival to be
measured with contact time.
An example of conducting a pilot test for a plug flow reactor using
ozone or another unstable disinfectant is prodded below.
Examole — Plug Flow Reactor Protocol
The size of the plug flow reactor can be approximated from the table
below. Glass, stainless steel, copper, plastic tubing or other material
compatible with the disinfectant can be used to construct the plug flow
reactor. Table 1 shows the approximate length of pipe for a plug flow
reactor to yield 10 minutes contact at flow rates between 50 and 500
al/mm. Cepending on pipe size and material an economical reactor can be
constructed.
TABLE 1 APPROA1MATE IEMGTH AND DImETU OP PIPE
flif b ON Etow
LINEAR PIPE LENGTH. METERS
N IMAL PIPE DI*aETU.
P1.00 TIME 4011SF 0 6 2 1 1 214 I I I S DR
mI / m m MIN 11195 CC 0 21 1 31 2 54 5 07 I I 40 20 27
$0
I C
05
500
17
7
4
4
2
0
I
0
0
4
0
2
lOG
10
1
1000
3S
1
0
0
3
9
2
0
0
9
0
S
200
10
2
2000
70
7
17
7
7
9
5
9
1
1
1
0
300
10
3
1000
10$
1
26
5
11
I
1
9
2
6
1
S
400
10
1
1000
111
5
35
4
15
7
7
9
3
5
2
0
500
10
5
5000
376
I
44
2
19.6
9
9
4
4
2
5
Additional information on the design of specific pilot studies can
be found in references by Thompson (1982), Montgomery (1985), and Al-Ani
(1985).
Additional Materials to those In 6.1 and/or 6.2
plug flow reactor
cyst suspension, ZxlO 7 cysts/trial
cyst quantity — cysts are prepared as Indicated in G.1.
10’ cysts/al X 20,000 ml a 2x10’ cysts required/trial
G.4 — 2

-------
MS2 stocks ZXIOIO/trial
2-20 liter (5 gal) carboy
test water pump, mid range 200 mi/mm
disinfectant generator
disinfectant pump, mid range 10-20 mi/m m
disinfecta&t residual reagents and equipment
lest Procedure
A. Reactor conditions
1. Test Water Flow rates 200 mi/mitt (this may vary from 50 to 500
mi/m m with 20 1 reservoir total experimental time 100 m m)
2. Disinfectant flow
gas-requires specific contactor designed for disinfectant
Liquidsi0 to 20 mi/n m
3. Temperature
controlled
4. Prepare 20 liter reservoir (5 gal) of test water at the pH and
temperature of the CT trial. Do not add microorganisms
5. Prepare 20 liter reservoir (5 gal) of test water and equi-
librate to the temperature of the CT trial. Add Giardia nu ns
cysts at an initial density of io cysts/mi andf or #452 bacter-
ia) virus at an initial density of 106 PFUJm1. Mix thoroughly
and adjust pH to the pH of the CT trial. Continuous mixing of
the test water feed stock should be carried out over the course
of the CT trial to prevent the Giardia cysts from settling.
8. Disinfection Procedure — Prior to Disinfection Trial
1. Determine contact time for the sawle ports in the plug flow
reactor under conditions of the CT trial by methods described
In Appendix C of the Guidance Manual.
2. Determine disinfectant concentration with no microorganisms in
the feed test water.
C. CT Trial Procedure
I. Start test water feed without cysts and or virus (approx. 200
el/sin), start disinfectant feed (gas or liquid).
G.4 - 3

-------
Allow system to equilibrate.
Monitor disinfectant residual by appropriate method during this
time. Samples for disinfectant residual should be taker,
directly into tubes or bottles containing reagents to fix the
disinfectant at the time the sample is collected. Keep a plot
of disinfectant residual vs running time to evaluate steady
state conditions.
2. After the disinfectant residual has stabilized, switch to the
reservoir containing the test microorganism(s).
3. Allow system to equilibrate for a time 3 X final contact
time.
example
final contact time 1O mm, allow 30 mm.
4. MonItor disinfectant residual by appropriate method during this
t;me. If the thsinfectant residual is stable begin chemical
and biological sampling for calculation of CT.
5. Samp
a.
ii ng
Chemical
A sufficient volume (about 250 ml should be collected from
the sampling tap prior to the biological composite to
deterini ne:
pH
Residual disinfectant — Samples
should be collected directly
into tubes or bottles containing
reagents to fix the disinfectant
at the time the sample is collected.
b. Biological
._Sa les for microbial analysis are collected as short time
co osite samples over a 10 to 20 minute time period.
Several trials uy run for a given 20 liter test water
preparation as long as sufficient equilibration and flow
recovery times are allowed between trials.
— Zero time samples should be collected as 250 ml
.ccsposite samples either directly from the test water
G.4 - 4

-------
feed reservoir or in line prior to the addition of
the disinfectant.
— Four 250 ml samples are collected separately into a 2
1 sterile bottle containing a neutralizing agent for
the particular disinfectant. Each sample is thor-
oughly mixed upon collection and stored at 4 C. If
multiple sample ports are used, the order of collec-
tion should be from longest to shortest contact time
to minimize flow changes due to sampling.
6. Giardia cyst recovery and assay.
Concentrate the 1000 ml composite sample by filtration accord-
ing to the method given in section G.1. Record and report the
data as described in section G.1. The expected cysts/sample is
given below:
Cysts/sample 4 x 250 ml X 10 cyst/ml 1x10 cyst/sample.
7. Virus Assay
Before filtration for Giardia remove 10.0 ml from the biologi-
cal composite sample to a sterile scr2w cap c ltLre tube
containing 2 to 3 drops chloroform. Assay for t4 52, record and
report the virus data according to the methods and procedures
described in G.2. Be sure to correct the Giardia sample volume
to 990 ml.
8. Calculation of CT
Calculate CT in a manner described in Section G.1 for Giardia
and Section G.2 for virus. The residual disinfectant should be
the average of the four residual determinations performed prior
to the individual samples collected for the biological compos-
ite and the time should be the time determined for the sample
port under similar flow conditions.
G.4 - 5

-------
REFERENCES
Al-Mi, C.S.tl., Filtration of Giardia Cysts and other substances:
Volume 3. Rapid Rate Filtration (EPA/500/2-85/027) 1985.
Montgomery 1 James N. Consulting Engineers Inc., Water Treatment Princi-
ples and Design , John Wiley and Sons, Inc., 1985.
Thonipscn. J.D. Overview of Pilot and Plant Studies, AWWA Seminar
Proceedings on Design of Pilot Studies, May 1982.
Wallis, P.M., Davies, 3.5., Nuthonn, R.,Bichanin-Mappin, J.M., Roach,
P.D., and Van Roodeloon, A. Removal and Inactivation of Giardla Cysts
in a Mobile Water Treatment Plant Under Field Conditions: Preliminary
Results. In Advances in Giardia Researcl3 . P.M. Waflis and B.R.
Hamand, eds, Union of Calgary Press, p. 137-144, 1989.
Wolfe, R.L., Stewart, N.H., Liange , 5.1., and McGulre, M.J., Disinfec-
tion of Model Indicator Organisms in a Drinking Water Pilot Plant by
Using PEROXOME, Applied Environmental Microbiology, vol 55, 1989, pp
2230 - 2241
Olivieri, V.P. and Sykora, 3.1., Field and Evaluation of CT for D c-
ter’nining the Adequacy of Disinfection. American Water Works Asso-
ciation Water Quality Technology Conference. In press, 1989.
G A — 6

-------
APPENDIX H
SAMPLING FREQUENCY FOR TOTAL COLIFORMS
IN IKE DISTRIBUTION SYSTEM

-------
TABLE H-i
TOTAL COLIFORM SAMPLING REQUIREMENTS
BASED UPON POPULATION
Nu imun Minimum
Number Number
Population of Sample 1 2 3) Population of Samples
Served Per Month ‘ Served Per Month
25 to 1,000 1 59,001 to 70,000 70
1,001 to 2,500 2 70,001 to 83,000 80
2,501 to 3,300 3 83,001 to 96,000 90
3,301 to 4,100 4 96,001 to 130,000 100
4,101 to 4,900 5 130,001 to 220,000 120
4,901 to 5,800 6 220,001 to 320,000 150
5,801 to 6,700 7 320,001 to 450,000 180
6,701 to 7,600 8 450,001 to 600,000 210
7,601 to 8,500 9 600,001 to 780,000 240
8,501 to 12,900 10 780,001 to 970,000 270
12,901 to 17,200 15 970,001 to 1,230,000 300
17,201 to 21,500 20 1,230,001 to 1,520,000 330
21,501 to 25,000 25 1,520,001 to 1,850,000 360
25,001 to 33,000 30 1,850,001 to 2,270,000 390
33,001 to 41,000 40 2,270,001 to 3,020,000 420
41,001 to 50,000 50 3,020,001 to 3,960,000 450
50,001 to 59,000 60 3,960,001 or more 480
Notes :
1. Non—community system.s using all or part surface water and community
systems must monitor total coliforn at this frequency. A non—
colunity water system using gro md water and serving 1,000 persons
or fewer must monitor qua.rteriy, beginning S years after the rule’s
promulgation, although this can be reduced to yearly if a ean tary
survey shows no defects. A non-community water system aerv .ng more
than 1,000 persona during any month, or a non—community water system
using surface water, must monitor at the same frequency as a like-
sized community public water system for each month the system
provides water to the public.
2. Unfiltered surface water systems must analyse one coliform sample
each day the turbidity exceeds INTU.

-------
TABLE K —i
TOTAL COLIFORM SAMPLING REQUIREMENTS
BASED UPON POPULATION (Continued)
3. Systems collecting fewer than 5 samples per month on a regular basis
must conduct sanitary surveys. Coamiunity and non-community systems
must conduct the initial sanitary surveys within S and 10 years of
promulgation, respectively. Subsequent surveys must be conducted
every 5 years, except for non—county systems using protected and
disinfected ground water, which have up to 10 years to conduct
subsequent surveys.

-------
TABLE 11-2
MONITORING MD REPEXT SMPLE FREQUENCY
S Routine
Systen Size Sa mples # Repeats More Monitoring For
Quarter1y 2 4 5/mo for I additional no
25 — 1,000 Month 1y 2 4 5/mo for I additional no
1,001 — 2,500 2/mo 3 5/mo for I additional no
2,501 — 3,300 3/mo 3 5/mo for 1 additional no
3,301 — 4,100 4/mo 3 5/mo for 1 additional to
4,101 — 4,900 5/mo 3 None
>4,9C0 Table 1 3 None
Notes :
1. Non-co nunity Water systems.
2. For exceptions, see Table 1.

-------
APPEl ZX I
MAINTAINING REDUNDANT
DISINFECTION CAPABILITY

-------
APP DIX I
REDUNDANT DISINFECTION CAPABILITY
The SSf R requires that unfiltered water systems provide redundant disin—
fection components to ensure the continuous application of a disinfectant to
the water entering the distribution system. In many systems, both filtered
and unfiltered, a primary disinfectant is used to provide the overall inac-
tivation/removal and a secondary residual is applied to maintain a residual in
the distribution system. As outlined in Sections 3.2.4 and 5.5.4, redundancy
of the disinfection system(s) is recoemended to ensure that the overall
treatment requirement of 3—log Giardia cyst and 4—log virus re—
moval/inactivation is achieved, and a residual is maintained entering the
distribution system. This is particularly important for unfiltered supplies
where the only treatment barrier is disinfection. Redundancy of components is
necessary to allow for disinfection during routine repairs, maintenance and
inspection and possible failures.
In reviewing water disinfection facilities for compliance with redundancy
requirements, the following items should be checked:
I. General
A. Are the capacities of all components of both the primary system and
the backup system equal to or greater than the required capacities?
Some systems may have two or more units that provide the required
dosage rates when all, units are operating. In these cases, an
additional unit is needed as backup, during the downtime of any of
the operating units. The backup must have a capacity equal to or
greater than that of the largest on—lime unit.
B. Are adequate safety precautions being followed, relative to the type
of disinfectant being used?
C. Ass redundant c iponents being exercised or alternated with the
primary c ponents?
D. Are all components being properly maintained?
B. Are critical spare parts on hand to repair disinfection equipment?
F. Are spare parts available for cimponente that are indiapensible for
disinfecting the water?

-------
II. Disinfectant Stcrag
A minimum of two storage units capable of being used alternately should
be provided. The total combined capacity of the storage units should provide
as a minimum the system design capacity.
A. Chlorine
Storage for gaseous chlorine will normally be in 150—lb cylinders,
2,000—lb containers, or larger on—site storage vessels.
1. Is there automatic switchaver equipment it one cylinder or
container empties or becomes inoperable?
2. Is the switching equipment in good working order, (manually
tested on a regularly scheduled basis), and are spare parts on
hand?
3. Are the scales adequate for at least two cylinders or contain-
ers.
B. Hypochlorite -
Storage of calcium hypochiorite or sodium hypochiorite is normally
provided in drums or other suitable containers. Redundancy requirements are
not applicable to these by themselves, as long as the required minimum storage
quantity is on hand at all times.
C. Ammonia
An hydrous ammonia is usually stored in cylinders as a pressurized
liquid. Aqua a nia is usually stored as a solution of ammonia and water in
a horizontal pressure vessel.
1. Is the available storage volume divided into two or more usable
units?
2. Is aut atic switching equipment in operation to change over
from one unit to another when one is empty or inoperable?
3. Are there spare parts for the switching equipaent7
III. Generation
Ozone -end -chlorine dioxide are nOt stored on-site. Rather, because of
their reactivity, they are generated and used i. m diately.
To satisfy the -redundancy requir ntI for these disinf.ctant it is
rec ended that two generating unite, or two s.ts of units, capable of
1—2

-------
supplying the required feed rate be provided. In systems there there is more
than one generation system. a standby unit should be available for tunes the
on—line units need repair. The backup unit should have a capacity equal to or
greater than the unit(s) it may replace.
A. Chlorine Dioxide
Chlorine, sodium chlorite, or sodium hypochiorite should be stored in
accordance with storage quide].ines previously described.
B. Ozone
Are all generation components present and in working order for both the
primary and the redundant units (whether using air or oxygen)?
C. Co m on
Is switchover and autonatie start—up equipment installed and operable to
change from the primary generating unit(s) to the redundant unit(s)?
IV. Feed Systems
Redundancy in feed systems requires two separate units, or systems, each
capable of supplying the required dosage of disinfectant. If more than one
unit is needed to apply the required feed rate, a spare unit should be avail-
able to replace any of the operating units during tines of malfunction. The
replacement unit should, therefore, have a capacity equal to or greater than
that of the largest unit which it may replace. This requirement applies to
all disinfection methods, and is beat implemented by housing the on-line and
redundant components in separate rooms, enclosures, or areas, as appropriate.
In reviewing these systems for redundancy, the following components
should be checked
A. Chlorine
1. Evaporators
2. Chlorinator.
3. Injectors
B. Hypochlorite
1. Ltxing tanks and mixers
2 • Chemical feed pimps and controls
3. Injectors
1-3

-------
C. Ozone
1. Dissolution equipment , including compressor and delivery piping
systems
IL Chlorine Dioxide
1. Chlorine £ red equipment
2. Sodium chlorite mixing and metering equipment
3. Day tank and mixer
4. Metering pumps
5. If a package d o 2 unit is used, two must be provided
£. Chloramination
1. Chlorine feed equipment
2. Aonia feed equipment, including applicable equipment for
either:
a. Anhydrous aronia (gas)
b. Aqua aronia (solution)
V. Residual Monitoring
The best method of monitoring a disinfection facility for continuous
operation is by continuous recording equipment. To improve reliability, it is
suggested that duplicate continuous monitors are present for backup in the
event of monitor failure. However, if there is a failure in the monitoring
system for indicating that a continuous residual is being maintained, the SWTR
allows systems to take grab samples every four hours for up to five days
during monitor repair. For systems without 24 hour staffing it will not be
practical to take grab samples and redundant monitoring equipment is
recnended. Failure of continuous monitoring would be a violation of a
monitoring requirement, not a treatoant requirement.
A. Chlorine
1. Does the facility have a continuous monitor for chlorine
residual at the disinfection system sits with an alarm or
indicator to show when the monitor is not functioning? For
added assurance, the provision of a backup monitoring unit is
also recceended.
2 • Is there instrtaentation in place to aut atically switch frca
one monitor to the other if the first one fails?
‘-‘.4

-------
B. Hypochlorjte
Same as for chlorine system.
C. Ozone
1. Does the facility have a continuous ozone monitor with automa-
tic swi tchover capabili.ty and alarms?
2. Does the facility have a continuous ozone residual monitor w .th
automatic switchover capabLlity and alarms?
D. Chlorine Dioxide
1. Does the facii .ity have a conti .nuous chlorine dioxide monitor
with automatic switchover capability and alarms?
2. Does the facility have a continuous chlorine dioxide res dual
monitor w .th automatic switchover capability and alarms?
E. Chloramination
1.. Does the facility have a continuous a onia monitor with
automatic switchover capability and alarm?
2. Does the facility also have a continuous chlorine residual
monitor on—site with automatic switchover capability and
alarms?
VI. Power Supply
A permanently installed standby generator, capable of running all, elec-
trical equipment at the disinfection station, and equipped for automatic
start-up on power failure, should be on—site end functional.
Alternatives to a standby generator, 8uch as a feed line from a different
power source, are acceptable if they can be shown to have equal reliability.
VII. Alarms
Indicatoxa and alaxma, both local and re te, should be capable of
promptly alaitinq øperating and supervisory personnel of problem conditions.
A. local
Lights, buzzera, and horns should be installed and functioning to alert
on-site personnel to problem conditions.
B. Remote
Alarm aignals should be relayed to a central control panel which is
manned 24 hours per day and whose operators can notify response personnel
imeediately.
I -5

-------
C. Problem Conditions
A minimum list of problem conditions which should have indicators and
alarms, both locally and at a 24-hour per day switchboard, are as followsg
1. Disinfectant leak
2. Feeder p p failure
3. power outage
4. Generator or alternate power source on
5. Disinfectant residual less than setpoint value
VIII. Facility Layout
Ma3cimum reliability is ensured when redundant units are separated from
pri.mary units. The type of separation should be appropriate to the type of
potential malfunction. For example, any area within a building sub eet to a
chlorine leak should have prLmary components separated from redundant compo-
nents by an airtight enclosure, i.e., separate rooms of varying sizes.
IX. Separate Facility
Under certain conditions, such as location of a disinfection facility in
an area of high earthquake potential, the most reliable mans of providing
redundant facilities may be to house them in a completely separate structures
at a different site.
1—6

-------
APPENDIX J
WATERSHED CONTROL PRCZPXI

-------
APP DIX J
WATERS D CONTROL PROGRAM
The following is a guideline for docunenting a watershed control program.
The SWTR only requires a watershed control program for unfiltered supplies. A
watershed control program can also benefit a filtered system by providing
protection for maintaining the source water quality, minimizing the level of
disinfection to be provided. It is therefore rec ended that all systems
conduct the basic elements of a watershed control program. However, the scope
of the program should increase as the complexity and size of the watershed/
system 1.ncreaseB. The program could be more or less comprehensive than this
outline, and will be determined on a case—by—case basis by the utility and the
Primacy Agency. In addition to the guidelines below, a well.head protection
program could be the basis of a watershed control program in many states. All
of the elements found below would also be part of a local welihead protection
program.
A. Watershed Description
1. Geographical location and physical features of the watershed.
2. Location of major components of the water system in relation-
ship to the watershed.
3. Hydrology: Annual precipitation patterns, stream flow charac—
terist.ics, etc.
4. Agreements and delineation of land use/ownership.
B. Identification of the Watershed Characteristics
and Activities Detrimental to Water Quality
1. Baturally Occurring:
a. Effect of precipitation 1 terrain, soil types and land
cover
b. Animal populations (describe) — include a discussion of
the Giardia contamination pot.ntial. , any ether microbial
contamination transmitted .by animals
c. Other — any other activity which can adversely affect
water quality
.7-1

-------
2. Man-Made:
a. Point sources of contamination such as wastewater treat-
ment plant, industrial discharges, barnyard, feedlots, or
private septic systems
The impact of these sources on the microbiological quality of
the water source should be evaluated. In cases resulting in
identifiable degradation, the discharges should be eliminated
in order to minimize the treaent of the water needed.
b. Nonpoa.nt Source of Contamination:
1) Road construction - major highways, railroads
2) Pesticide usage
3) Logging
4) Grazing animals
5) Discharge to ground water which recharges the surface
source
6) Recreation activities
7) Potential for unauthorized activity in the watershed
8) Describe any other human activity in the watershed
and its potential impact on water quality
It should be noted that grazing animals in the watershed may
lead to the presence of Cryptosporidium in the water. Crypto-
sporidium is a pathogen which may result in a disease outbreak
upon ingestion. No information is available on its resistance
to various disinfect.ants, therefore it is rec ended that
grazing should not be permitted on watersheds of non—filtering
systems. Sewage discharges will introduce viruses into the
water source which may be occluded in solids and protected from
inactivation through disinfection. It is, therefore, recom-
mended that sewage discharges should not be permitted within
watersheds of non-faltering supplies. Although it is prefer-
able to nit have grazing or sewage discharges within the
watershed, Primacy Agencies will need to evaluate the impact of
these activities on a case—by—cas. basis. In cases where there
‘ ts’t tong deteniion time and a high degree of dilution between
tii point âTt CI activity and the jater intake, these activ-
ities may be permissible for unfiltered supplies. The utility
ihould set priorities to address the impacts in 8.1. and 2.,
Snsideiing thezr health significance and the ability to
control them.
. 1-2

-------
C. Control of Detrimental Activities/Events
Depending art the activities occurring within the watershed, various
techniques could be used to eliminate or minimize their effect.
Describe what techniques are being used to control the effect of
activities/events identified in B.l. and 2. in its yearly report.
Example:
Activity : Logging in the watershed.
Management Decision : Develop program to minimize impact of
logging.
Procedure : Establish agreements with logging companies to
maintain practices which will minimize adverse impacts on water
quality. These practices should include:
— limiting access to logging sites
— ensuring cleanup of sites
— controlling erosion from site.
Monitoring Periodically review logging practices to ensure
they are consistent with the agreement between the utility and
the logging companies.
Examples
Activity : Point sources of discharge within the watershed.
Management Decision : Eliminate those discharges or minimize
their impact.
Procedures : Actively participate in the review of discharge
permits to alert the reviewing agency of the potential (actual}
impacts of the discharge and lobby for its elimination or
strict control.
Monitoring : Conduct special monitoring to ensure conditions of
the permit are met and to doctent adverse effects on water
quality.
D. Monitoring
I. .Routine: ?4in i mum specifications for monitoring several raw
water quality parameters are listed in Section 3.1. Describe
when, where and bow these samples will be collected. These
results will be used to evaluate whether the source may con-
tinue to be used without filtration.
I I- 3

-------
2. Specific: Routine monitoring may not provide information about
all parameters of interest. For example, it may be valuable to
conduct special studies to measure contaminants suspected of
being present ( Giardia , pesticides, fuel products, enteric
viruses, etc.). Frequent presence of either Giardia or enteric
viruses in raw water samples prior to disinfection would
indicate an inadequate watershed control program. Monitoring
may also be useful to assess the effectiveness of specific
control techniques, and to audit procedures or operational
requirements instituted within the watershed. Utilities are
encouraged to conduct additional monitoring as necessary to aid
them in controlling the quality of the source rater.
E. Management/Operations
1.. Management
a. Organizational structure
b. Personnel and education/certification requirements
2. Operations
a. Describe system operations a-nd design flexibility.
b. The utility should conduct same form of ongoing review or
survey in the watershed to identify and react to potential
impacts on water quality. The scope of this review should
be doc ented and agreed upon by the utility and Primacy
Agency on a case—by—case basis.
c. Specifically describe operational changes which cart be
made to ad)ust for changes in water quality. Example:
Switching to alternate sourcess increasing the level of
tisj.n.tectioni using settling basins. Discuss what trig-
g.ra , and who decides to make, those changes.
3. Annual Report: As part of the watershed program, an annual
report ehould be suheitted to the Primacy Agency. The contents
of the Teport should:
a. Identify special concerns that occurred in the watershed
and bow they were h Aisd (example: herbicide usage, new
construction, etc.).
b. &ti rise .other activities in the watershed such as
logging, hunting, water quality monitoring, etc.
c. Project. ivhat ‘adverse activities are expected to occur in
the future snd describe how the utility expects to address
them.
3—4

-------
F. Agreements/Land Ownership
The goal of a watershed management program is to achieve the highest
level of raw water quality practicable. This is particularly
critical to an unfiltered surface supply.
1. The utility will have maximum opportunity to realize this goal
if they have complete ownership of the watershed. Describe
efforts to obtain ownership, such as any special programs or
budget. When complete ownership of the watershed is not
practical, efforts should be taken to gain ownership of cnti—
cal elements, such as, reservoir or stream shoreline, highly
erodable land, and access areas to water system facilities.
2. Where ownership of land is not possible, written agreements
should be obtained recognizing the watershed as part of a
public water supply. Maximum flexibility should be given to
the utility to control land uses which could have adverse
effect on the water quality. Describe such agree nts.
3. Describe how the utility ensures that the landowner complies
with these agreements.

-------
APPENDIX K
SANITARY SURVEY

-------
APPENDIX K
SANITARY SURVEY
The SWIR requires that an on-site inspection be conducted each year as
outlined In Section 3. It is recomended that at the onset of determining
the classification of a source water that a detailed sanitary survey be
conducted. In addition, it is recomended that a sanitary survey such as
contained in this appendix be conducted every 3 to 5 years by both
filtered and unfiltered systems to ensure that the quality of the water
and service is maintained. This time period is suggested since the time
and effort needed to conduct the comprehensive survey makes it impractical
for it to be conducted annually. A periodic sanitary survey is also
required under the Total Coliforin Rule for systems collecting fewer than
5 samples/month. The survey must be conducted every 5 years for all
systems except for protected ground water systems which disinfect. These
systems must conduct the survey every 10 years.
The sanitary survey involves three phases 4 includirg planning the
survey, conducting the survey and compiling the final report of the
survey, as will be presented In the following pages.
1. Planning the Survey
Prior to conducting or scheduling a sanitary survey, there should
be a detailed review of the water system’s file to prepare for
the survey. The review should pay particular attention to past
sanitary survey reports and correspondence describing previously
identified problems and their solutions. These should be noted 4
and action/inaction regarding these problems should be specifi-
cally verified in the field. Other information to review
Includes: any other correspondence, water system plans, chemical
and microbiological sampling results, operating reports, and
engineering studies. This rev ew will aid in the familiarization
with the system’s past history and present conditions, and the
agency’s past Interact onsi’tlth the system.
The initial phase of-the ater quality review will be carried out
pr1or to.conducting heasurvey..as well, -and will consist of
revIew ng the water system’ s monitoring records. Records should
be reviewed for compijence tth all applicable microbiological,
1norganl c chemIcaI 1 :or an1C c tca1 , and radiological contami-
1%ant NC [ s and also far lance with the monitoring require-
ments for those contaminants. The survey will provide an
opportunity to review these records with the utility, and to
K-I

-------
discuss solutions to any MCL or monitoring violations. The
survey will also provide an opportunity to review how and where
samples are collected, and how field measurements (turbidity,
chlorine residual, fluoride, etc.) are made. Points to cover
Include:
a. Is the system in compliance with all applicable MCLs
(or anic chei ical, inorganic chemical 1 microbiological, and
radiological)?
b. Is the system In compliance with all monitoring require-
ments?
The pre-survey file review should generate a list of Items to
check in the field, and a list of questions about the system.
It will also help to plan the format of the survey and to esti-
mate how much time it may take. The next step is to make the
initial contact with the system management to establish the
survey date(s) and time. Any records, files, or people that will
be referenced during the survey should be mentioned at the
outset. Clearly laying out the Intent of the survey up front
will greatly help in managing the system, and will ensure that
the survey goes smoothly without a need for repeat trips.
2. Conducting the Survey
The on-site portion of the survey is the most important and will
involve interviewing those in charge of managing the water system
as well as the operators and other technical people. The survey
will also review all major system components from the source(s)
to the distribution system. A standard form is frequently used
to ensure that all major components and aspects of each system
are consistently reviewed. However, when in the field it is
best to have an open mind and focus most attention on the specif-
ics of the water system, using the for. only as a guide. The
surveyor should be certain to be on time when beginning the
survey. This consideration will help get the survey started
smoothly wIth the ,operator and/or .anag r.
As the survey progresses, any deficiencies that are observed
should be brought to the attention of the water system personnel.
and the problem arid the corrective measures should be discussed.
It is far better.tp clirify technical detaflsand solutions while
standing iiext b he problem than it js: to do so over the
telephone. Poi*ts to cover lncludéi
a. Is the vpe ’atbrcompetent In performing the necessary field
teiting f rooerational control?
b. #re -testing ,fa ilifr ie , nd equipment adequate, and do
•eagents)iSe4)’!.ak animexpJ ed shelf life?

-------
c. Are field and other analytical instruments properly and
regularly calibrated?
d. Are records of field test results and water quality
compliance monitoring results being maintained?
e. Conduct any sampling which will be part of the survey.
Also, detailed notes of the findings and conversations should be
taken so that the report of the survey will be an accurate recon-
struction of the survey.
Specific components/features of the system to review and some
pertinent questions to ask are:
A. Source Evaluation
All of the elements for a source elevation enumerated below may
also be part of a Wellhead Protection Program.
1. Description: based on field observations and dis-
cussion with the operator, a general characterization
of the watershed should be made. Features which
could be included in the description are:
a. Area of watershed or recharge area.
b. Stream flow.
c. Land usage (wilderness, fari land, rural
housing, recreational, cownercial, industrial,
etc.).
d. Degree of access by the public to watershed.
e. Terrain and soil type.
f. Vegetation.
g. Other.
2. Sources of contamination in the watershed or
sensitive areas. urrounding wells or well fields
shouW be .identit d. . Not only should this be
determined by pI yslc41ly touring and observing the
watershed and its daily uses, but the surveyor should
also actively questton th water system manager about
advErse and potegtIa3l e4verse activities tn the
watershed.. . An exa 1e o 1 types of contamination
.lnc4udes:
K-3

-------
a. Man Made.
1. Point discharges of sewage 1 stor ater,
and other wastewater.
2. On-site sewage disposal systems.
3. Recreational activities (swiuining,
boating, fishing, etc.).
4. Human habitation.
5. PestIcide usage.
6. Logging.
7. Highways or other roads from which there
might be spills.
8. Comnerclal or industrial activity.
9. SolId waste or other disposal facilities.
10. Barnyards, feed lots, turkey and chicken
farms and other concentrated domestic
animal activity.
11. Agricultural activities such as grazin 9 ,
tillage, etc., which affects soil
erosion, fertilizer usage, etc.
12. Other.
b. Maturally Occurring.
1. Animal populations, both domestic and
wild.
2. Turbidity fluctuations (from precipita-
tion, landslides, etc.).
3. Fires.
4; Inoiganic contaminants from parent
materials (e.g., asbestos fibers).
5; £tgaebIoo.s.
6 Other.
This list ls.by no means all Inclusive. The
surveyor should rely principally on his

-------
observations and thorough questioning regarding
the unique properties of each watershed to
completely describe what may contaminate the
source water.
3. Source Construction.
a. Surface Intakes.
1. Is the source adequate in quantity?
2. Is the best quality source or location
In that source being used?
3. Is the intake protected from icing
problems if appropriate?
4. Is the intake screened to prevent entry
of debris, and are screens maintained?
5. Is animal activity controlled within the
iunedlate vicinity of the Intake?
6. Is there a raw water sampling tap?
b. Infiltration Galleries.
1. Is the source adequate In quantity?
2. is the best quality source being used?
3. Is the lid over the gallery watertight
and locked?
4. Is the collector in sound condition and
maintained as necessary?
5. Is there a raw water sampling tap?
c. - Springs.-
1. Is the source adequate in quantity?
2. 1s there adequate protection around the
spring such as fencing to control the
area within 200 feett
3. isthe spring conflr!icted to best capture
the spring flai-sn4 xc ljade surface water
inf4ltrat l pn?
K-5

-------
4. Are there drains to divert surface water
from the vicinity of the spring?
5. Is the collection structure of sound con-
struction with no leaks or cracks?
6. Is there a screened overflow and drain
pipe?
7. Is the supply Intake located above the
floor and screened?
8. Is there a raw water sampling tap?
d. Catchment and Cistern.
1. Is source adequate In quantity?
2. Is the cistern of adequate size?
3. Is the catchment area protected from
potential contamination?
4. Is the catchment drain properly screened?
5. Is the catchment area and cistern of
sound construction and in good condition?
6. Is catchnent constructed of approved
non-toxic, non-leaching material?
7. Is the cistern protected from contamina-
tion —— manholes, vents, etc?
8. Is there a raw water tap?
e. Other Surface Sources.
1. Is the source adequate In quantity?
2. Is the best possible source being used?
3. Is th e iite vicinity of the source
protected 4100 contamination?
4. Is the structure in good condition and
prooerlv Cbnstructed?
S. iserera r iJflg tap?
k-6

-------
4. Pumps 1 Pumphouses, and Controls.
a. Are all intake pumps, booster pumps 1 and other
pumps of sufficient capacity?
b. Are all pumps and controls operational and
maintained properly?
c. Are check valves, blow off valves, water meters
and other appurtenances operated and maintained
properly?
d. Is emergency power backup with automatic
start-up provided and does it work (try it)?
e. Are underground compartments and suction wells
waterproof?
f. Is the Interior and exterior of the pumphouse
In good structural condition and properly
maintained?
g. Are there any safety hazards (electrical or
mechanical) in the pumphouse?
I i. Is the pumphouse locked and otherwise protected
against ‘vandalism?
1. Are water production records maintained at the
pumphouse?
5. Watershed Management (controlling contaminant
sources): The 9 oal of the watershed management
program is to identify and control contaminant
sources in the watershed (see Section 3.3.1 of this
document, Watershed Control Prograr). Under ideal
conditions each source of contamination identified
in 2 will already have been identified by the
-.utIl4ty, and some means of control instltpted, or a
factual determination made that its Impact on water
quality Is insignificant. To assess the degree to
ithich the watershed management program Is achieving
its goal, the following types of inquiries could be
made:
rs.: elf :the Watershed Is not entirely owned by the
r . e ut1i1ty,-havewrlttnagreements been made with
ter. uother land owners to control land usage to the
:1. - satisfaction of the utility? Are appropriate
re : regulations -under the contract of flate/local
IeZT 3.%tPM ’taetttf health f r i effect?
-g --r.2:. ck.jr.ta4flt.
K-7

-------
b. Is the utility making efforts to obtain as
complete ownership of the watershed as
possible? Is effort directed to control
critical elements?
C. Are there means by which the watershed is
regularly inspected for new sources of
contaittination or trespassers where access is
limited?
d. Are there adequately qualified personnel
employed by the utility for identifying
watershed and water quality problems and who
are given the responsibility to correct these
problems?
e. Are raw water quality records kept to assess
trends and to assess the 1 act of different
activities and contaminant control techniques
In the watershed?
1. Has the system responded adequately to concerns
expressed about the source or watershed in past
sanitary surveys?
g. Has the utility Identified problems in its
yearly watershed control reports, and if so,
have these problems been adequately addressed?
h. Identify what other agencies have control or
jurisdiction in the watershed. Does the
utility actively Interact with these a9encies
to see that their policies or activit es are
consistent with the utility’s goal of
maintaining high raw water quality?
B. Treatment Evaluation
1. Disinfection.
a. Is the disinfection equipment and disinfectant
appropriate for the application (chloramlnes,
chlorine, ozone, and chlorine dioxide are
generally accepted dj infectants)?
b Are there back-up disinfection units on line
In se of failur are th y operational?
C , Is t hTjre auxiliary pr With aUtomatic start
upiñ case of p r outage? Is it tested and
operated on a regular basis, both with and
without load?
K-8

-------
d. Is there an adequate quantity of disinfectant
on hand and is it properly stored (e.g., are
chlorine cylinders properly labeled and
chained)?
e. In the case of gaseous chlorine, is there
automatic switch over equipment when cylinders
expire?
f Are critical spare parts on hand to repair
disinfection equipment?
g. Is disinfectant feed proportional to water
flow?
h. Are daily records kept of disinfectant residual
neat the first customer from which to calculate
CTs?
1. Are production records kept from which to
determine CTs?
j. Are CTs acceptable based on the level of
treatment provided (see Surface Water Treatment
Rule for CT values, and Sections 3 and 5 of
this guidance manual for calculation of CT).
k. Is a disinfectant residual maintained in the
distribution system, and are records kept of
daily measurements?
1. If gas chlorine is used, are adequate safety
precautions being followed (e.g., exhaust fan
with lnta e within six inches of the floor,
:self—contained breathing apparatus that is
regularly tested, regular safety training for
employees, aemonia bottles and/or automatic
‘chlorine detectors)? Is the system adequate
to ensure the safety of both the public and the
ee loyees n the event of a chlorine leak?
2. Other.
a. Are other treatment processes appropriate and
- are they operated to produce consistently high
weteçtqualt y?.
b. Are pi s, chemical feeders, and other
-. .scbaMcal . qulpmeot in good condition and
prQperiy.a1ata aed? -.
k-9

-------
c. Are controls and instrumentation adequate for
the process, operational, well maintained and
calibrated?
d. Are accurate records maintained (volume of
water treated, amount of chemical used, etc.)?
e. Are adequate supplies of chemical on hand and
properly stored?
f. Are adequate safety devices available and
precautions observed?
Sections of a sanitary survey pertaining to systems
containing filtration facilities have been omitted,
as this section of the guidance document pertains to
non-fl ltering systems.
C. Distribution System Evaluation
After water has been treated, water quality must be
protected and maintained as it flows through the distribu-
tion system to the customer’s tap. The following questions
pertain to the water purveyor’s ability to maintain high
water quality during storage and distribution.
1. Storage.
a. Gravity.
1. Are storage reservoirs covered and
otherwise constructed to prevent
contamination?
2. Are a l overflow lines, vents, drain-
lines, or cleanout pipes turned downward
and screened?
3. Are all reservoirs Inspected regularly?
4. Is the storage capacity adequate for the
system?
5. Does the reservoir (or .reservoirs)
provide sufficient pressu -throughoUt
the system?
5. Pine surface coatings wlthla:the-reservOir
4ngood repair and acc!p ab1e for potable
tier ontact7
K-iD

-------
7. Is the hatchcover for the tank watertight
and locked?
8. Can the reservoir be isolated from the
system?
9. Is adequate safety equipment (caged
ladder, OSHA approved safety belts, etc.)
in place for climbing the tank?
10. Is the site fenced, locked, or otherwise
protected against vandalism?
11. Is the storage reservoir disinfected
after repairs are made?
12. Is there a scheduled program for cleaning
storage reservoir sediments, slime on
floor and side walls.
b. llydropneumatic.
I. is the storage capacity adequate for the
system?
2. Are instruments, controls, and equipment
adequate, operational, and maintained?
3. Are the interior and exterior surfaces
of the pressure tank in good condition?
4. Are tank supports structurally sound?
5. Does the low pressure cut in provide
adequate pressure throughout the entire
system?
6. Is the pump cycle rate acceptable (not
acre than 15 cycles/hour)?
2. Cross Connections.
a. Is the system free of known uncontrolled cross
connect Ions?
b. Does the. .utillty ..b ave a cross connection
prevention progr , -including annual testing
of ,.backflow-pr.yention devicas?
c. Are backflcii prevention dêvicisinstalled at
all appropriate locations (wasteiiater treatment
plant. industrial -locations, hospitals, etc.)?
k -I I

-------
3. Other.
a. Are proper pressures and flows maintained at
all times of the year?
b. Do all construction materials meet AWWA or
equivalent standards?
c. Are all services metered and are meters read?
d. Are plans for the system avail able and current?
e. Does the system have an adequate maintenance
program?
— Is there evidence of leakage in the
system?
- Is there a pressure testing program?
— Is there a regular flushing program?
— Are valves and hydrants regularly
exercised and maintained?
— Are AWWA standards for disinfection
followed after all repairs?
— Are there specific bacteriological
criteria and limits prescribed for new
line acceptance or following line
repairs?
— Describe the corrosion control program.
— Is the system Interconnected with other
systems?
0. Management/OperatIon
1. Is there an organization that is responsible for
providing the operation, maintenance, and management
of the water system?
2. Does the utility regularly suarize both current and
long-ten, problems Identified In their watershed, or
other parts of the systems and define how they intend
to solve the problems i.e. Is their plannin
ecltanisa effective; do they follow through wit
plans?
K- 12

-------
3. Are customers charged user fees and are collections
satisfactory?
4. Are there sufficient personnel to operate and manage
the system?
5. Are personnel (including management) adequately
trained, educated, and/or certified?
6. Are operation and maintenance manuals and manufactur-
ers technical specifications readily available for
the system?
7. Are routine preventative maintenance schedules
established and adhered to for all components of the
water system?
8. Are sufficient tools, supplies, and maintenance parts
on hand?
9. Are sufficient operation and maintenance records kept
and readily available?
10. Is an emergent y plan available and usable, and are
employees aware of it?
11. Are all facilities free from safety defects?
When the survey is completed, It is always preferable to
briefly surinarize the survey with the operator(s) and
management. The main findings of the survey should be
reviewed so it is clear that there are not misunderstand-
ings about findings/conclusions. It is also good to thank
the utility for taking part In the survey, arranging
interviews with employees, gathering and explaining their
records, etc. The information and help which the utility
can provide an invaluable to a successful survey, and every
attempt should be made to continue a positive relationship
with the system.
3. ReportIng the Survey
A final report of the survey should be completed as soon as
possible to formally notify the system and other agencies of the
findings. There is no set or necessarily best format for doin
so, and the length of the report will depend on the findings o
the survey and size of the system. Since the report may be used
for future compliance actions and Inspections, It should include
as a .in1mt : 1) the date of the survey; 2) who was present
during the survey; 3) the findings of the survey; 4) the
reccemended improvements to Identified proble.s and 5) the dates
IC-13

-------
for completion of any improvements. Any differences between the
findings discussed at the conclusion of the survey and what’s
included in the final report should be discussed and clarified
with the utility prior to sending out the final report. In other
words, the utility should be fully aware of the contents of the
final report before receiving it.
k-14

-------
APPENDIX L
SMALL SYSTEM CONSIDERATIONS

-------
APPENDIX L
SMALL SYSTZMS CQNSIDERATONS
Introduction
Under the provisions of the SWTR, systems with fewer than 500 service
connections may be eligible for an exemption. Guidance on the requirements
for an exemption is provided in Section 9. For systems which are not eligible
for an exemption, compliance with the SWTR is mandatory. It is recognized
that the majority (approxi.mately 75 percent) of people in the United States
are served by a relatively small number of large Systems. However, most water
systems in the United States are small. For small systems, compliance with
the various previsions of the SDWA has traditionally been a problem. Records
show small systems have a disproportionately higher incidence of drinking
water quality and monitoring difficulties. The reasons for these difficulties
can generally be broken down into the following three categories:
— Economics
— Treatment Technologies
— Operations Uack of qualified personnel)
Small water systems typically face severe economic constraints. Their
lack of operating revenues results in significant limitations on their ability
to respond to the requirements of the SOWA. These systems cannot benefit from
the economies of scale which are available to larger systems.
The second difficulty facing the small systems has been the lack of
appropriate treatment technologies. Although methods for removing most of the
contaminants known to occur in drinking water are available many of these
technologies have only recently been scaled down for the smaller systems.
The third problem which has traditionally plagued small systems is the
lack of well trained operators. This deficiency is the result of many com-
bined factors. First of all, many of these operators are employed only on a
part—time basis or if they are employed on a full-time basis they have a
myriad of additional duties. In addition, the operator’s technical background
may be limited as well. This results from the low salary of the position.
which is uninviting to qualified operators. Also, in spite of the requirement
f_—I

-------
of retaining certified operators upheld in many states, it seems to be diffi-
cult to enforce this requirement in small systems.
The purpose of this appendix is to provide assistance to the Primacy
Agency in defining the problems and potential solutions typically associated
with small systems. It is beyond the scope of this document to provide an
indepth dicussion of the needs of small systems. However, over the past
several years the needs of the small water systems have been recognized to be
of primary concern and numerous workshops, seminars and cos ittees have been
attempting to more clearly define workable solutions. A partial listing of
the papers, reports and proceedings which discuss problems and solutions
pertaining to small systems beyond that which is possible in this manual is
presented in the reference list of this appendix.
Economics
One of the most severe consr.raints of small systems is the small economic
base from which to draw funds. Certain treatment and services must be pro-
vided for a cosm unity regardless of how few people are served. Thus, as the
nwnber of connections to the system decrease, the cost per connection in-
creases. The economic limitations of small utilities makes it difficult to
provide needed upgrading of existing facilities or an adequate salary to
maintain the employment of a qualified operator to monitor and maintain the
system. Adding to the severity of the economic hardships of small systems is
the fact that many of the small water systems are privately owned, with
private ownership increasing as system size decreases. The ownership of the
plant presents difficulties since privately owned systems are sub ect to rate
controls by the local, public utility co nission, are not eligible for public
grants and loans, and may find cosmercial loans hard to obtain.
Financing options for small systems include; ‘federal and state loan and
grant programs, federal revenue’ sharing and revenue bonds (for municipal
systems) md - loans through the United states Small Business Administration
(SBA) and’use’óf ‘industr ial development bonds or privatization (for private
utilities). These options are explained in greater detail in the Guidance
ManuaL. st .tutienal lternatives for Small Water Systems (AWWA, 1986).
L-2

-------
The following paragraphs will explain some existing options which may ease the
hardship of fina.ncing small water treatment facilities.
The ma or cause of small system difficulties arises from the lack of
funds and resources. It is therefore in the best interest of small utilities
to expand their economic base and the resources available to them, to achieve
the economies of scale available to larger systems. Regionalization is the
physical or operational union of s mall systems to effect this goal. This
uiuon can be accomplished through the physical interconnection of two or more
small systems or the connection of a smaller system to a pre—existing larger
system. Water supply systems can also oin together for the purchase of
supplies, materials, engineering services, billing and maintenance. The union
of the small systems increases the population served, thereby dispersing the
operational costs and decreasing the cost per cons wier.
The creation of utility satellites is another form of regionalization. ?
satellite utility is one which taps into the resources of an existing larger
facility without being physically connected to, or owned by, the larger facil-
ity. The larger system may provide any of the following for the smaller
system:
1. Varying levels of technical operational, or managerial assistance on
a contract basis.
2. Wholesale treated water with or without additional services.
3. Assuming ownership, operation and maintenance responsibility when
the small system is physically separate with a separate source.
The formation of a satellite offers many advantages for both the
satellite and the parent utility. These advantages include: an improved
economy of scale for satellites, an expanded revenue base for the parent
utility, provisions of needed resources to satellites, the retention of the
satellites’ local autonomy, improved water quality management of the
satellite, improved use of public funds for publicly ned satellites.
In order to create a re definite structure for the union of resources
of v ter treatment facilities, water districts may be created. Water
districts are formed by county officials and provide for the public ownership
of the utilities. The utilities in any given district would combine resources
and/or physically connect systems so that one or two facilities would provide
L-3

-------
water for the entire district. The creation of water districts creates
eligibility for public rnoiues, has the potential for economies of size,
facilitates the takeover or contract services with publicly owned non—cosmun-
ity systems and small privately owned systems, and offers a tax advantage.
Drawbacks include subjection to politics, a strong local planning effort is
needed for success, and competition with private enterprises.
The centralization of utilities can be taken one step further through the
creation of county utilities or even state utilities. The government will
create a board which may then act to acquire, construct, maintain and operate
any public water supply within its district, the system may provide water on
its own or purchase water from any municipal corporation. The board may adopt
and administer rules for the construction, maintenance, protection and use oi
public water supplies and the fixation of reasonable rates for water supplies.
The cost of construction and/or upgrading -of facilities may be defrayed
through the issuance of bonds and/or property assessment. As with all the
alternatives, the creation of government control of the utilities has its
advantages and disadvantages. The advantages include: the creation of
central management, creation of economy of scale for utilities, eliqibility
for public grants and loans, savings through centralized purchasing, manage-
ment, consultation, planning and technical assistance, and possible provision
for pool of trained operators. The disadvantages include the sub)ectivity to
politics, the slow response caused by bureaucracy, and competition to private
contractors.
Treatment Technologies
The high cost of available treatment technologies has limited their use
in small water supply systems. Recently prefabricated package plants and
individual treatment units have been developed to lessen these costs. At the
present time, the treatment technologies which are available to enable systems
-to comply with the Safe Drinking Water Act are identified to be the following:
— Package plants
— Slow—sand filters
— Diatomaceous earth filters
Cartridge filtration
A brief discussion of each treatment method is provided below.
t.-4

-------
Package Plants
Clarification and filtration units which require minimal assembly in the
field can now be manufactured. To minimize required operator skill level and
operational attention, the equipment should be automated. Continuous effluent
turbidity and disinfectant residual monitoring systems with alarms and
emergency shutdown provisions are features that safeguard water quality and
should be provided for unattended plants.
Slow—Sand Filters
Slow-sand filters are applicable to small, water supply systems. Their
proven record of effective removal of turbidity and Giardia cysts makes them
suitable for application where operational attention is minimal. Since no
chemicals other than a disinfectant are needed, and no mechanical equipment is
involved, the required operator skill level is the lowest of the filtration
alternatives available to small systems.
Diatomaceous Earth Filters
Diatomaceous earth (OS) ressure and vacuum filters can be used on
relatively low turbidity surface waters (less than 1 to 2 NTU) for removal of
turbidity arid Giardia cysts. DE filters can effectively remove particles as
small as 1 micron, but would require coagulating chemicals and special filter
aids to provide significant virus removal.
Cartridge Filters
Cartridge filters using inicroporous ceramic filter elements with pore
sizes as small as 0.2 urn may be suitable for producing potable water, in
combination with disinfection, from raw water supplies containing moderate
levels of turbidity 1 algae, protozoa and bacteria. The advantage to a small
system, is, with the exception of chlorination, that no other chemicals are
required. The process is one of strictly physical removal of small particles
by straining as the water passes through the porous membranes. Other than
occasional cleaning or membrane replacement, operational requirements are not
complex and do not require skilled personnel.
Selection of a Filtration Technoloqy
The criteria for aelection of filtration technology for a small co in—
ity are casentially the same as those for a larger cosmunity. That is, the
utility must first screen the complete list of available alternatives to
L- 5

-------
eljnu.nate those which are either not technically suited to the existing
conditions (Table 4—1) or not affordable by the utility. Remaining alterna-
tives should then be evaluated based on both cost (capital, annual, and
life-cycle) and non—cost bases (operation and maintenance, technical require-
ments versus personnel available; flex2.bility regarding futue needs; etc.).
In these evaluations it should be noted that even though automated package
plants are cost-competitive with slow sand filters, their operation require—
ments to achieve optimum performance could be complicated. Also, the
maintenance requirements for package plants would be mechanically and
electrically oriented and might require a maintenance agreement with the
manufacturer.
During the process of installing the treatment system, interim measures
should be taken to ensure the delivery of a reasonably safe water to the
consumers. In addition to the available interim measures listed in
Section 9.3, temporary installation of mobile filtration plants may be
possible. These trailer—mounted units are sometimes available from state
agencies for emergencies, but more often may be rented or leased from an
equipment manufacturer.
Modification of Existing Filtration Systems
Small treatment systems that are already in existence should comply with
the performance criteria of the SWTR. If the systems are not found to be
performing satisfactorily, modifications to the existing process may be
required. Improvement in treatment efficiency depends on the type of filtra-
tion system in use. Operation of slow sand filters could be checked for bed
depth, short—circuiting, excessive hydraulic loading, and for the need to pre-
treat the raw water. Infiltration galleries, or s times, roughing filters
ahead of a slow sand filter may provide for better performance by reducing the
solids load on the filters. However, .he design criteria and costs for this
alternative have not yet been defined. $i .te specific studies may be required
before roughing filters could be used to ichieve compliAnce with the regula-
tions: - Diatomacec.us earth WE) filters should be checked for appropriate
precoat and body feed application, hydraulic J oadinq,.qrAde (size) of E being
used. possible need for chemic4 pretreatment. Package plants would have
to be - chicked process-by-process, similar to the system used for a

-------
conventional plant. Other filtration processes would have to be checked for
hydraulic lotting rate, appropriateness of the filter material (pore size)
and possible need for additional pretreatment.
Disinfection
Dis i nfection C’T ) requirements for small systems can be met in several
different ways: The most obvious method of maintaining a disinfectant
residual in the distribution system is to add disinfectant at one or more
additional locations. An alternate method is to increase the disinfectant
dose at the existing application point(s). The latter alternative, however,
may increase disinfectant byproducts, including THMs, in the system.
If it is a relatively short distance between the treatment system and the
first customer, additional contact time can be prov i ded so that the
disinfectant dose does not have to be increased beyond desirable residuals.
Two specific methods of increasing contact time for small systems are
i i installing a pressure vessel or closed storage vessel, baffled to provide
adequate contact time, or 2) cth structing a looped pipeline, on the finished
water line between the filtration—disinfection system and the first customer.
The feasibility of either of these methods would depend on system specifics
that include size, physical conditions, and cost.
If it is not practical to provide additional storage time to achieve the
desired a, an alternate, more effective disinfectant may be used. An
alternate disinfectant may provide a sufficient CT without altering the system
configuration.
Operations
Water treatment facilities need to be operated properly in order to
achieve maximum treatment efficiencies. There is currently a lack of well
trained operators at many small treatment plants. The main cause is lack of
awareness of the importance of correct plant operation, lack of training
programs, lack of enforcement of the requirement for employment of a certified
operator and lack of funds to employ such an operator.
Small systems may wish to implement a circuit rider/operator program. In
this program a qualified, certified, experienced operator works for several
water supply systems. The rider can either directly operate the plants, or
1.- 7

-------
provide technical assistance to individual plant operators, by acting as a
trainer through cn—the—30b supervision. The latter would be preferable since
it could create a pool of well trained operators.
The main cause of inadequately trained operators is the lack of well
established training programs. Until such training programs are begun,
systems must depend on other training means, such as seminars and books. One
resource which may be helpful in running the plant is ‘Basic Management
Principles for Small Water Systems — An AWWA Seta U-Systems Resource Book”,
1982.
Most package plant manufacturers’ equipment manuals include at least
brief sections on operating principles, methods for establishing proper
chemical dosages, instructions far operating the equipment, and troubleshoot-
ing guides. An individual who studies these basic instructions and receives
comprehensive start-up training chould be able to operate the equipment
satisfactorily. These services are vital to the successful performance of a
package water treatment plant ai d should be a requirement of the package plant
manufacturer. The engineer designing a package plant facility should specify
that start-up and training services be provided by the manufacturer, and also
should consider requiring the manufacturer to visit the plant at 6-month and
1—year intervals after start—up to ad)ust the equi.pittent, review operations,
and retrain operating personnel. Further, this program should be ongoing and
funds should be budgeted every year for at least one revisit by the package
plant manufacturer.
Another way for small systems to obtain qualified plant operation would
be to contract the services of administrative, operations, and/or maintenance
personnel from a larger neighboring utility, government agencies, service
companies or consulting firms. These organizations could supply assistance in
financial and legal planning, engineering, purchasing accounting and collec-
tion servicss, laboratory support, licensed operators or operator training,
treatment and water quality assurance, regulatory Liaison, and/or emergency
assistance. Through the contracting of these services the utility provides
for the resources needed, improves water quality management and retains its
autonomy. However, if and .then the contract is tcr inated, the utility
returns to its original status.
L—8

-------
References
American Water Works Association. Basic Management Principles for Small Water
ystems . 1982.
American Water Works Association. Design and Construction of Small Water
Systems , 1934.
Kelly, G dley, Blair and Wolfe, Inc. Guidance Manual - Institutional
Alternatives for Small Water Systems . AWWA Research Foundation Contract
79—84, l9 .
L-9

-------
APPENDIX II
PROTOCOL FOR DEMONSTRATION
OF EFFECTIVE TREATMENT

-------
APPENDIX N
PROTOCOL FOR DEMONSTRATION
Of EFFECTIVE TREATMENT
This appendix presents approaches which can be taken to demonstrate
overall effective removal and/or inactivation of Giardia cysts.
M.1 Demonstration for Alternate Technology
Systems using a filtration technology other than those enumerated
in the SWTR may demonstrate the effectiveness of the treatment process
through pilot or full scale testing. As a minimum, testing should be
conducted when the source exhibits its worst case annual conditions. Some
systems may have two periods of ‘worst case’ water quality Including the
cold water in winter or algae blooms during the suurer.
Pilot units should Include the following:
— filtration rate of the pilot system equal to filtration
rate on full scale unit
- pilot filter diameter greater than or equal to SO times
the media diameters (Robeck, et al 1959)
— media diameter, depth, and size gradation should be
identical to full scale 1
— coagulant dosing Identical to full scale
— any mixing and settling occurring before filtration in
the full scale plant should be reproduced as closely as
possible in the pilot. Mixing should be of the same G
value(s), and the detention time for settling should be
close to the average flow detention time for the
projected full scale plant.
According to the SWTR, alternate technologies must be capable of
meetin the same turbidity performance criteria of slow sand filtration
systems. 1bui the filtered water from the process should be monitored
continubuslyor with grab samples every four hours for turbidity. The
requirement for reeting turbidity performance h s been established to
N - i

-------
ensure that there will be no interference of turbidity with virus
inactivation through disinfection.
Following the demonstration of meeting the turbidity requirements,
the level of Giardth cyst removal achieved must be determined. The
protocol in M.2 may be followed for this demonstration.
M.2 Particle Si n Analysis Demonstration for Giardia Cyst Removal Credit
Particle size analysis may be used to demonstrate the level of
actual Giardia cyst removal provided by the system. This demonstration
can be done using samples from the full scale plant or a pilot unit.
In the case of either a full scale or pilot scale demonstration,
removal of particles in the range of 5 to 15 urn In diameter should be
detemined using an electronic particle counter that has been calibrated
with latex spheres. If a light blockage device Is used (e.g. HIAC) this
calibration should have been done during installation of the device. The
calibration should be checked before taking measurements for the purposes
of this demonstration. Samples should be diluted appropriately to ensure
that measurements do not reflect coincident error. Coincident error
results when more than one particle passes the detector at one time,
causing an inaccurate particle count and diameter measurement. An
electrical sensing zone device (e.g. Coulter Counter or Elzone) may also
be used. Appropriate dilutions, electrolyte strength 4 and calibration
procedures should be followed (these are scheduled to be outlined in the
17th edition of Standard Methods). When using an electrical sensing zone
instrument, an orifice no larger than 125 urn and no smaller than 40 urn
should be used since only particles between 2% and 40% of the orifice
diameter are accurately sized and counted (karuhn et al 1975).
Sa les of the filter influent and effluent should be taken 5
minutes after the backwashed filter is plaEed in operation, and every 30
minutes thereafter for the fIrst 3 hourstbt.operatlon, followed by hourly
samples u inti l backwash (Wlesner-etat 1987). *11 samplesihould show
at least it2_log removal. The sbIiR estabflshes en overalfttreatment
requIreméiii of 3—log Giardia cystié hljiäctivat’ionP”ThuL disinfec-
M-2

-------
tion must be provided to supplement the particulate removal and meet this
requirement.
Samples from repeated filter runs may be averaged at each sampling
time, but samples should not be averaged within one filter run.
Additional suggestions on particle counting technique (Wiesner
1985):
1) if particle Counts are not determined invnediately upon
sampling (within 10 minutes) samples should be diluted.
2) For an electrical sensing zone measurement. samples
should be diluted 1:5 to 1:20 with a 1 ’partic e-free”
electrolyte solution (approximately 1% NaC1) containing
100 particles per ml or fewer.
3) For a light blockage measurement, particle free water
should be used to dilute samples.
4) Dilutions should be done to produce particle concentra-
tions as close to the tolerance for coincident error as
possible to minimize background counts.
5) Particle counts should be determined within 8 hours of
sampling.
6) All sampling vessels should be washed with laboratory
detergent, double rinsed in particle free water, and
rinsed twice with the water being sampled at the time
of sampling.
The log reduction of particles in the size range of 5 to 15 urn in
size can be assumed to correspond to the log reduction of Giardia cysts
which would be achieved.
P 1.3 Demonstration for Increased Turbidity Allowance
Based upon the requirements of the SWTR, the minimum turbidity
performance criteria for systems using conventional treatment or direct
filtration is filtered water turbidity less than or equal to 0.5 NTU in
95 percent of the measurements taken each month. However, at the dis-
cretion of the Primacy Agency, filtered water turbidity levels of less
than or equal to 1 NTU In 95 percent of the measurements taken every month
P4-3

-------
may be permitted on a case-by-case basis depending on the capabtilty of
the total system to remove and/or inactivate at least 99.9 percent of
Giardi a lamblia cysts.
Treatment plants that use settling followed by filtration 1 or direct
filtration are generally capable of producing a filtered water with a
turbidity of 0.2 NTLI or less. The most likely cause of high turbidities
in the filtered water is incorrect coagulant dosing (O’Melia, 1974).
Regardless of the turbidity of the raw or finished water, coagulant
addition at some point prior to filtration is required to destabilize
particles for removal in the filter. Only plants documenting continuous
coagulant feed prior to filtration should be eligible for being allowed
higher filtered water turbidities than the 0.5 NTU requirement. At plants
that continuously feed coagulant and do not meet the 0.5 NTU requirement.
a series of jar tests, and perhaps sand column filtration tests (in batch)
should be performed to evaluate the optimum coagulant dose for turbidity
-removal.
In the event that plants can document continuous coagulant feed.
and, after running the plant under conditions determined In batch testing
to be optimal for turbidity removal, still do not meet the 0.5 NTU
requirement, effective filtration status may still be appropriate. This
would further be supported if it can be shown that the full scale plant
is capable of achieving at least a 2-log reduction in the concentration
of particles between 5 and 15 urn in size through particle size analysis
as outlined In Section M.2. Where a full scale plant does not yet exist,
appropriately scaled-down pilot filters might be used for such a
demonstration.
Disinfection
The level of disinfection could also be considered for determining
when to allow a higher turbidity performance criterion for a system. For
example, If a system achieves 3-log Glardia cyst inactivation through
disinfection, as determined by CT values, it may be appropriate to allow
higher filtered water turbiditles (I.e. greater than 0.5 MU but less
than 1 MU In 95 percent of the measurements and never exceedIng 5 MU).
- 14-4

-------
As an extension of this concept, if a system achieves 2-log Giardia cyst
inactivation and is able to demonstrate greater than a 1-log reduction in
concentration of particles between 5 and 15 urn 1 in accordance with the
procedure discussed In the previous section 1 this could provide a basis
for allowing filtered water turbidity limits above 0.5 NTU but less than
1 NTU in 95 percent of the measurements.
The expected level of fecal contamination and Giardia cyst
concentrations in the source water should be considered in the above
analysis. High levels of disinfection (e.g., 2 to 3—log inactivation of
Giardia cysts), in addition to filtration which achieves less than 0.5 NTU
in 95 percent of the measurements may be appropriate, depending upon
source water quality. Further guidance on the level of disinfection to
be provided for various source water conditions Is provided In Section
4.4.2. In all cases the minimum disinfection to be provided must
supplement the particulate removal to ensure at least a 3-log Giardia cyst
removal/inactivation.
p4 5

-------
References
American Public Health Association; American Water Works Association;
Water Pollution Control Federation. Standard Methods for the Examination
of Water and Wastewater , 17th ed. (supplement), September 1989.
Coulter Electronics 600 W. 20th Street, Hialeah, FL 33010-2428
Karuhn, R.; Davies, R.; Kaye, B.; Clinch, H. Studies on the Coulter
Counter Part I. Powder Technology Volume II, pp. 157-171, 1975.
O’Melia, C. The Role of Polvelectrolytes in Filtration Processes , EPA -
67012-74-032, 1974.
Robeck, G.; Woodword, R. L. Pilot Plants for Water Treatment Research,
Journal of Sanitary Engineering ASCE Vol. 85;SA4; 1, August 1959.
Wiesner, P4. 0ptimum Water Treatment Plant Configuration Effects of Raw
Water Characteristics, 1 dissertation John Hopkins University, Baltimore,
MD, 1985.
Wiesner, H.; Rook, J. J.; Fiessinger, F. Optimizing the Placement of GAC
Filters, J. AWWA VOL 79, pp. 39-49, Dec 1987.

-------
APPENDIX N
PROTOCOLS FOR POINT-OF-USE
DEVICES

-------
UNLTED STATES
ENVIRONMENTAL PROTECTION AGENCY
Registration Division
Office of Pesticide Programs
Criteria and Standards Division
Office of Drinking Water
GUIDE STANDARD A!JD PROTOCOL FOR
TESTING MICROBIOLOGICAL WATER PURIFIERS
Report of Task Force
Submitted April, 1986
Revised April, 1987

-------
CONTENTS
PREFACE
1. GENERAL N-i
2. PERFORMANCE REQUIREMENTS N-6
3• MICROBIOLOGICAL WATER PURIFIER TEST PROCEDURES N -S
APPENDIX N-i StTh4MARY FOR BASIS OF STANDARDS AND N-23.
TEST WATER PARAMETERS
APPENDIX N—2 LIST OF PARTICIPANTS IN TASK FORCE N-29
APPENDIX N- ] RESPONSE BY REVIEW SUBCOMMITTEE TO N-3i
PUBLIC COMMENTS

-------
Preface
The protocol presented in this paper can be applied to demonstrate the
effectiveness of new technologies as well as point-of—use devices. The
evaluation presented here deals with the removal of partaculates and
disinfection. In areas which pertain to disinfection, the guidelines
contained in Appendix C take precedence.

-------
1. GENERAL
1.1 Irtroduction
The subject of microbiological purification for waters of unknown micro-
biological quality repeatedly presents itself to a variety of governmental and
non—governmental agencies, consumer groups, manufacturers and others. Exam—
pies of possible application of such purification capabilities include:
— Backpackers and campers
— Non-standard military requirements
— Floods and other natural disasters
— Foreign travel and stations (however, not for extreme contamination
situations outside of the U.S.)
— Contaminated individual sources, wells and springs (however, not for
the conversion of waste water to sticrobiologically potable water)
— Motorhomes and trailers
Batch methods of water purification based on chlorine and iodine disir—
fection or boiling are well known, but many situations and personal choice
call for the consideration of water treatment equipment. Federal agencies
specifically involved in responding to questions and problems relating to
microbiological purifier equipment include:
— Registration Division, Office of Pesticide Programs (OPP), Environ-
mental Protection Agency (EPA): registration of microbiological
purifiers (using chemicals);
— Compliance Monitoring Staff, EPA: control of microbiological
purifier device claims (non—registerable products such as ultra-
violet units, ozonators, chlorine generators, others);
— U.S. Army Medical Bioengineering Research and Development Laboratory
(USMBRDL), U.S. Army Natick Research and Develo zient Center and
other Army and military agencies: research and development for
possible field applications;
— Criteria and Standards Division, Office of Drinking Water (ODW),
EPA: Consideration of point—of—use technology as acceptable tech-
nology nn r the Primary Drinking Water Regulations consumer
information and service;
N-i

-------
— Drinking Water Research, Water Engineering Research Laboratory
(WERL , EPA; responsible for water treatment technology research;
— Microbiology Branch, Health Effects Research Laboratory (HERL), EPA;
responsible for study of health effects related to drinking water
filters.
A number of representatives of the above mentioned agencies provided
excellent participation in the task force to develop microbiological testing
protocols for water purifiers. Major participation was also provided by the
following:
— A technical representative from the Water Quality Association;
— A technical representative from the Environmental Health Center,
Department of Health and Welfare of Canada; and
— An associate professor (microbiology) from the University of
Arizona.
1.2 Basic Principles
1.2.1 Definition
As set forth in EPA Enforcement Strategy and as supported by a Federal
Trade Cosctission (FTC) decision CFTC v. Sibco Products Co., Inc., et al.,
Nov. 22, 1965), a unit, in order to be called a microbiolog .ca1 water
purifier, must remove, kill or inactivate all types of disease—causing micro-
organisms from the water, including bacteria, viruses and protozoan cysts so
as to render the processed water safe for drinking. Therefore 1 to qualify, a
microbiological water purifier must treat or rerove all types of challenge
organisms to meet specified standards.
1.2.2 General Guide
The standard and protocol will be a general guide and, in some cases, may
present only the minimum features and fr work for testing. While basic
features of the standard and protocol have been tested, it was not feasible to
conduct full—fledged testing for all, possible types of units. Consequently,
protocol users ihould “include -pie--testing -4f—their units in a testing rig,
including the sampling techniques -to be used. Where •users of the protocol
find good reason to alter or add to the guide in order to meet specific
operational problems,_t9use an alternate organism or Laboratory procedure, or
to respond to innovative treatment unitn without decreasing the level of

-------
testing or altering the intent of the protocol, they should feel free to do
so. For example, the OPF Registration Division might find it necessary to
amend the guide somewhat for different types of treatment units. Another
example would be ultraviolet W.V.) units, which nay have specific require-
ments in addition to the guide protocol.
1.2.3 Performance—Based
The standard will be performance-based, utilizing realistic worst case
challenges and test conditions and use of the standard shall result in water
quality equivalent to that of a public water supply meeting the
microbiological requirements and intent of the National Primary Drin3cing Water
Regulations.
1.2.4 Exceptions
A microbiological water purifier must remove, kill or inactivate all
types of pathogenic organisms if claims are made for any organism. However,
an exception for limited claims may be allowed for units removing specific
organisms to serve a definable environmental need (i.e., cyst reduction units
which can be used on otherwise disinfected and isicrobiologically safe drinking
water, such as a disinfected but unfiltered surface water containing cysts.
Such units are not to be called microbiological water purifiers and should not
be used as sole treatment for an untreated raw water.)
1.2.5 Not to Cover Non—Microbiological Reduction Claims
The treatment of water to achieve removal of a specific chemical or ether
non-microbiological substances from water will not be a part of this standard.
National Sanitation Foundation (NSF) Standards 42 (Aesthetic Effects) and 53
(Health Effects) provide partial guides for chemical removal and other claims
testing.
1.2.6 Construction and Information Exclusions
While the standard reco ends safe, responsible construction of units
with non-toxic materials for optimum operation, all such items and associated
operational considerations are excluded as being beyond the scope of the
standard. Included in the exclusion are materials of construction, electrical
and safety aspects, design and construction details, operational instructions
and information, and mechanical performance testing.
1.2.7 Research Needs Excluded
N-3

-------
The guide standard and protocol must represent a practical testing
program and not include research recorndations. For example, consideration
of mutant organisms or differentiation between injured and dead organisms
would be research items at this time and not appropriate for inclusion in the
standard.
1.2.8 Not to Consider Sabotage
Esoteric problems which could be presented by a variety of hypothetical
terrorist (or wartime) situations, would provide an unnecessary complication,
and are not appropriate for inclusion in the standard.
1.2.9 Continuity
The guide standard and protocol will be a living document, sub ect to
revision and updating with the onset of new technology and knowledge. it is
recommended that the responsible authorities for registration and drinking
water quality review potential .needs every two to three years and reconvene
the task force upon need or upon request from the water quality industry, to
review and update the standard and testing protocol.
1.3 Treatment Units Coverage
1.3.2 Universe of Possible Treatment Units
A review of treatment units that might be considered as microbiological
purifiers discloses a number of different types covering treatment principles
ranging from filtration and chemical disinfection to ultraviolet light ra-
diation.
1.3.2 Coverage of This Standard
in -view of the limited technical data available and in order to expedite
the wdrk of the taak force, the initial coverage is limited, on a priority
basis, to three basic types of microbiological water purifiers or active
components with their principal ans of action as follows:
1.3.2.1 Ceramic Filtration Candles or Units (may or
may not contain a chemical bacteriostatic agent )
Filtration, and adsorption, - and chemical anti-microbial activity if a
chemieal is included.
1:L :2 Ralogenated Resins and Units
N-4

-------
Chenical disinfection and possibly filtration. (Note: While not
included in this guide standard, halogen products far dis .nfection or systems
using halogen addition and fine filtration may be tested using many of its
elements, i.e.,, test water paraneters, microbiological challenge and reduction
requirements, analytical techniques and other pertinent elements.)
1.3.2.3 tlitraviolet WV) TJruts
UV irradiation with possible add—on treatment for adsorption and filtra-
tion (not applicable to IJV units for treating potable water from public water
supply systems).
1.3.3 Application of Principles to Other Units
While only three types of units are covered in this standard, the princi-
ples and approaches outlined should provide an initial guide for the testing
of any of a nu sber of other types of units and/or systems for the microbiolog-
ical purification of con -minated water.
N-5

-------
2. PEFORMANC REQ 7IRE1ZNTS
2.1 Microbiological Water Purifier
In order to make the claim of “microbiological water purifier,” units
must be tested and demonstrated to meet the microbiological reduction require-
ments of Table 1 according to the test procedures described in Section 3
(Appendix N—i) for the specific type of unit involved.
2.2 Chemical Health Limits
Where sliver or some other pesticidal chemical is used in a unit, that
chemical concentration in the effluent water must meet any National Primary
Drinking Water Ilaxisium Contaminant Level (MCL), additional Federal guidelines
or otherwise be demonstrated not to constitute a threat to health from con-
sumption or contact where no MCL exists.
2.3 Stability of Pesticidal Chemical
Where a pesticidal chemical is used in the treatment unit, the stability
of the chemical for disinfectant effectiveness should be sufficient for the
potential shelf life and the projected use life of the unit based on manufac-
turer’s data. Where stability cannot be assured from historical data and
information, additional tests will be required.
2.4 Performance Limitations
2.4.1 Effective Lifetime
The manufacturer must provide en explicit indication or assurance of the
unit’s effective use lifetime to warn the-consumer of potential diminished
treatment capability either through:
a. Having the unit terminate discharge ãf treated water, or
b. Sounding an alarm, or
c. Providing simple, explicit instruction for servicing or replacing
units within the recomeended use life (measurable in terms of volume
throughput, specific time frame or other appropriate method).
2.4.2 Limitation on Use of Iodine
N-6

-------
EPA policy initially developed in 1973 and reaffirmed in 1982 (memo of
March 3, 1982 from 7. A. Cotruvo to G. A. Jones, sub3ect: “Policy on Iodine
Disinfection) is that iodine disinfection is acceptable for short-term or
limited or emergency use but that it is not recor nended for long-term or
routine corununity water supply application where iodine—containing species may
remain in the drinking water.
N-7

-------
3. NIcR0BIOLOGIcAL WATER PURIFIER TEST PROCEDURES
3.1 Purpose
These tests are performed on ceramic filtration candles or units, halo-
genated resins and units and ultraviolet (UV) units in order to substantiate
their microbiological re val capabilities over the effective use life of the
purifier as defined in Table 1 and, where a pesticidal chemical is used, to
determine that said chemical is not present in the effluent at excessive
levels (see Section 3.5.3.4, Appendix N).
3.2 Apparatus
Three production units of a type are to be tested, simultaneously, if
feasible; otherwise, in a manner as similar to that as possible.
Design of the testing rig must parallel and simulate projected field use
conditions. For plumbed—in units a guide for design of the test rig may be
taken from “Figure 1: Test Apparatus_SchetnaticR (p. A-2 of Standard Number 53
“Drinking Water Treatment Units —— Health Effects, 0 National Sanitation
Foundation). Otherwise, the test rig must be designed to simulate field use
conditions (worst case) for the unit to be tested.
3.3 Test Waters —— Non—Microbiological Parameters
In addition to the microbiological influent challenges, the various test
waters will be constituted with chemical and physical characteristics as
follows:
3.3.1 Test Water *1 (General Test Water )
This water is intended for the normal non—stressed (non—challenge) phase
of testing for all units and shall have specific characteristics which may
easily be obtained by the adjustment of many public system tap waters, as
follows:
a. !t shall be free f any chlorine or other disinfectant residual;
b. pH — 6.5 — 8.5,
c. Total Organic Carbon (T OC) 0.1 - 5.0 agIL ;
d. Turbidity 0.1 — 5 NTU;
N-S

-------
e. Terperature 20 C S C; and
f. Total Dissolved Solids (TDS) 50 - 500 mg/I..
3.3.2 Test Water #2 (Challenge Test Water/Halogen Disinfection )
This water is intended for the stressed challenge phase of testing where
units involve halogen disinfectants (halogen resins or other units) and shall
have the following specific characteristics:
a. Free of chlorine or other disinfectant residual;
b. (1) p H 9.0 .2, and
(2) for iodine-based units a pH of 5.0 .2 (current information
indicates that the low pH will be the most severe test for virus
reduction by iodine disinfection);
c. Total Organic Carbon (TOC) not less than 10 mg/Li
d. Turbidity not less than 3D NTU;
e. Temperature 4 C I C; and
f. Total Dissolved Solids (TOS) 1,500 mg/I. - 150 mg/I..
3.3.3 Test Water #3 (Challenge Test Water/Ceramic Candle
or Units With or Without Silver Impregnation )
This water is intended for the stressed challenge phase of testing for
the indicated units but not for such units when impregnated with a halogen
disinfectant (for the latter, use Test Water *2). it shall have the following
specific characteristics:
a. It shall be free of any chlorine or other disinfectant residualj
b. pH 9.0 .2,
c. Total Organic Carbon (TOC) — not less than 10 mg/Li
d. Turbidity — not less than 30 wru,
e. Tei erature4C1C; and
f. Total Dissolved Solids (TOS) — - l-,-SOO mg/I. ISO mg/L.
3.3.4 Test Water *4 (challenge Test Water for Ultraviolet Units )
This water is intended for the stressed phase of testing for L IV units and
shall have the following specific characteristics:
N-9

-------
a. Free of chlorine or other disinfectant residual;
b. pH 6.5 — 8.5;
c. Total Organic Carbon (TOC) —— not less than 10 mg/Li
d. Torbidity —— not less than 30 NTU;
e. Temperature 4 C • 1 C,
f. Total Dissolved Solids (TDS) —— 1,500 mg/i 150 mg/L;
g. Color U.V. absorption (absorption at 254 nm) —- Sufficient para—
hydroxybenzoic acid (P1fBH) to be just below the trigger point of the
warning alarm on the U.V. unit. (Note that Section 3.5.1.1 provides
an alternative of adjusting the U.V. lamp electronically, especially
when the U.V. lamp is preceded by activated carbon treatment.)
3.3.5 Test Water 05 (Leaching Test Water for Units Containing Silver )
This water is intended for stressed leaching tests of units containing
silver to assure that excess levels of silver will not be leached into the
drinking water. It shall have the following specific characteristics:
a. Free of chlorine or other disinfectant residual;
b. pH —— 5.0 0.2;
c. Total Organic Carbon (TOC) — approximately 1.0 mg/L;
d. Turbidity —— 0.1 — S NTUj
e. Temperature —— 20 C 5 C; and
f. Total Dissolved Solids (TDS1 —— 25 — 100 mg/L. -
3.3.6 Recommended Materials for Adjusting Test Water Characteristics
a. pH: inorganic acids or bases (i.e., HC1, NaOH);
b. Total Organic Carbon (TOC): humic acids;
c, Tu.rbidity A.C. Pine Test Dust (Park No. 1543094)
fr : A.C. park Ping Division
General Motors Corporation
1300- tlorth Dort Highway
Punt, lich1gan 48556;
d. Total Dissolved Solids (TDS): sea salts, Sigma Chemical Co., 89883
1St. Louis,MO) oz.ai, ,ther equivalent source of TDS;
N- 10

-------
e. Color tJ.V. Absorption: p-hydroxybenzoic acid (grade: general
purpose reagent).
3.4 Analytical Methods
3.4.1 Microbiological Methods
Methods in this section are considered state—of—the—art” at the time of
its preparation and subsequent improvements should be expected. Methods used
for microbiological analyses should be compatible with and equal to or better
than those given below.
3.4.1.1 Bacterial Tests
a. Chosen Organism: Klebsiella terrigena (AT C-332S7).
b. Method of Production: Test organism will be prepared by overnight
growth in nutrient broth or equuralent to obtain the organ sm in the
stationary growth phase (Reference: Aaburg, S.D., Methods of
Testing Sanitizers and Bacteriostatic Substances In: Disinfection,
Sterilization and Preservation , Seymour S. Block, ed., pp. 964-980,
1983). The argaitiam w .ll be collected by centrifugation and washed
three times in phosphate buffered saline before use. A1ternat vely,
the organisms may be grown overnight on nutrient agar slants or
equivalent and washed from the slants with phosphate buffered
saline. The suspensions should be filtered through sterile Whatman
Number 2 filter paper (or equivalent) to remove any bacteri.al
clumps. New batches of organisms must be prepared daily for use in
challenge testing.
c. State of organism: organisms in the stationary growth phase and
suspended in phosphate buffered saline will be used.
d. Assay Techniques: Assay may be by the spread plate, pour plate or
membrane filter technique on nutrient agar, LF.C. or m-Endo medium
( Standard Methods for the Examination of Water and Wastewater , 16th
edItion, 1985, APHA). Each sample dilution will be assayed in
triplicate.
3.4.1.2 Virus Tests
a. Chosen Organisms: Poliovirus type 1 (LSc) (ATCC-VR-59), and Rota-
virus Strain SA-li (ATCC-VR-899) or WA (ATCC-VR-2018).
b. Method of Production: All stocks should be grown by a method
described by Smith and Gerba (in Methods in Environmental Virology ,
pp. 15—47, 1982) and purified by the procedure of Sharp, et al.
(Appl. Microbiol., 29:94-101, 1975), or similar procedure (Berman
and Hoff, Appi. Environ. Microbiol., 48:317—323, 1984), as these
methods will produce largely monodispersed virion particles.
N-Il

-------
c. State of the Organism: Preparation procedure will, largely produce
monodispersed particles.
d. Assay Techniques: Poliovirus type 1 may be grown in the ECM, MA-104
or other cell line which will support the growth of this virus. The
rotaviruses are best grown in the 14A—104 cell line. Since both
viruses can be assayed on the MA-104 cell line, a challenge test may
consist of equal amounts of both viru 9 es as a mI.xture (i.e., the
mixture must contain at least 1.0 x 10 /inL of each virus). Assays
may be as plaque forming wilts (PPU) or as ismunofluorescence foci
(IF) (Smith and Gerba, In: Methods in Environmental Virology ,
pp. 15—47, 1982). Each dilution will be assayed in triplicate.
3.4.1.3 Cyst Tests
a. Chosen Organism
1. Giardia lamblia or the related organism, Giardia nuns , may be
used as the challenge cyst.
2. Where filtration is involved, tests with 4—6 micron spheres or
particles have been found to be satisfactory and may be used as
a substitute for tests of occlusion using live organisms (see
Table 1). Spheres or particles may only be used to evaluate
filtration efficacy. Disinfection efficacy can only be evalu-
ated with the use of viable Giardia cysts.
b. Method of Production: Giardia nuns may be produced in laboratory
mice and Giardia lamblia may be produced in Mongolian gerbils;
inactivation results based on excystation measurements correlate
well with animal infectivity results.
c. State of the Organism: Organisms may be separated from fecal
material by the procedure described by Sauch (Appl. Environ.
Nicrobiol., 48:454—455, 1984) or by the procedure described by
Bingham, et al. (Exp. Panasitol., 47:284-281, 1979).
d. Assay Techniques: Cysts are first reconeentrated (500 ml., minimum
sample size) according to the method of Rice, Hoff and Schaefer
(Appl. Environ. Microbiol., 43:250—251, 1982). The excystation
method described by Schaefer, et al. (Trans., oyal Soc. of Txop.
Ned. a Ryg. 78:795-800, 1984) shall be used to evaluate Giardia
as,xis cyst viability. For Ciardia lamblia cysts, the excystation
method described by Bingham and Meyer (Nature, 277*301—302, 1979) or
Rice-and Schaefer (.7. din. Ilicrobiol., l4 709—710, 1981) shall. be
used. Cyst viability may also be determined by an assay method
involving the counting of .trophozoites as well as intact cysts
(Bingham, et al. , Exp. Parasitol., 47&284—293, 1979).
3.4.2 Chemical and Physical Methods
N- 12

-------
All physical and chemical analyses shall be conducted in accordance with
procedures in Standard Methods for the E cantination of Water and Wastewater ,
16th Edition, American Public Health Association, or equivalent.
3.5 Test Procedures
3.5.1 Procedure — Plumbed—in Units
a. 1. Install three production units of a type as shown in Figure 1
and condition each unit prior to the start of the test in
accordance with the manufacturer’s instructions with the test
water without the addition of the test contaminant. Measure
the flow rate through each unit. The unit shall be tested at
the maxi.mum system pressure of 60 psig static and flow rate
will not be artificially controlled.
2. Test waters shall have the defined characteristics continuously
except for test waters 2, 3 and 4 with respect to turbidity.
The background non—sampling turbidity level will be mainta3.ned
at 0.1-5 NTU but the turbidity shall be increased to the
challenge level of not less than 30 rru in the following
manner:
— In the “on” period(s) prior to the sampling “on” period.
— In the sampling “on” period when the sample actually will
be taken. (Note: at least 10 unit void volumes of the 30
NTU water shall pass through the unit prior to actual
sampling so as to provide adequate seasoning and uni—
fortn.tty before sample collection.)
b. 1. Use appropriate techniques of dilution and insure continual
mixing to prepare a challenge solution containing the bacterial
contaminant. Then spike test water continuously with the
influent concentration specified in Table 1.
2. Use appropriate techniques to prepare concentrated virus and
Giardia suspensions. Feed these suspensions into the influent
stream so as to achieve the influent concentrations specified
in Table 1 in the following manner:
— In the “on” period(s) prior to the sampling “on” period.
— In the sampling “on” period when the sample actually will
e taken. (Note; at least 10 unit void volumeB of seeded
water shall pass through the unit prior to sampling so as
to provide adequate seasoning and uniformity before sample
collection.)
N-i. 3

-------
c. Purge the system of the uncontaminated water with a sufficient flow
of contaminated test water. Start an operating cycle of 10 percent
on, 90 percent off with a 15 to 40 minute cycle (Example: 3 minutes
on, 27 minutes off) with the contaminated test water. This cycle
shall be continued for not more than 16 hours per day (minimum dE.ly
rest period of 8 hours). The total program shall extend to 100% of
est mated volume capacity for halogenated resins or units and for
10—1/2 days for ceramic candles or units and U.V. units.
d. Sampling: Samples of influent and effluent water at the specified
sampling points shall be collected as shown below for the various
units: these are minimum sampling plans which may be increased in
number by the investigator. All samples shall be collected in
duplicate from the flowing water during the sampling ‘on” portion cf
the cycle and they shall be one ‘unit void volume” in quantity (or
of appropriate quantity for analysis) and represent worst case
challenge conditions. Effluent samples shall usually be collected
near the middle of the sampling “on” period (or the whole volume
during one ‘on” period) except for samples following the specified
‘stagnation” periods, for which sampling shall be conducted on the
first water volume out of the unit. Each sample will be taken in
duplicate and shall be retained and appropriately preserved, if
required, for chemical or microbiological analysis in the event
verification is required. (For units where the volume of a single
“on” period is insufficient for the required analysis, samples from
successive “on” periods may be accumulated until a sufficient volume
has been collected.)
1(a). Sampling Plan: Halogenated Resins or Units (Non—iodine Based)
Tests
Test Point Active
(% of Estimated Test Influent Agent/
Capacity) Water aackground Residual Z(icrobio logical
Start General X X
25% X X
50% X X
After 48 hours
stagnation R X
60% chal— X X
75% lenge X
After 48 hours pH t
stagnation 9.0 0.2 X
100% X X
1(b). Sampling Plan: - Zodinated Resins or Units
N- 14

-------
Tests
Test Point Active
(% of Estimated Test Influent Agent/
Capacity) Water Background Residual Microbiological
Start General X X X
25% X X
50% X X
After 48 hours
stagnation x X
60% Chal— X X
75% lenge X X
After 48 hours pH —
stagnation 9.0 0.2 X X
90% chal— X x
100% lenge X x
After 48 hours pH —
stagnation 5.0 0.2 X x
2. Sair ling Plan: Ceramic Candles or Units and U.V. Units
Tests
Test Inf luent
Test Point Water Background Microbiological
Start General X X
Day 3 (middle) X
Day 6 (middle) x
After 48 hours
stagnation x
Day 7 (middle) X
Day 8 (near end) Chal-
After 48 hours lange
stagnation X
Day 10-1/2 X
(Note: All days are running days and exclude stagnation periods. When
the units contain silver, a leaching test shall be conducted as shown in
Section 3 .5.l.e and Buyer residual will be measured -at each microbiological
aair Ung point.)
N-I 5

-------
e. Leachthg Tests for Si]verized Units: Where the unit contains
silver, additional tests utilizing Test Water 05 will be conducted
as follows:
Tests
Influent
Test Point Background Silver/Residual
Start X X
Day2 X
After 48 hours
stagnation X
f. Alternate Sampling Plans:
1. Since some laboratories may find it inconvenient to test some
units on a 16 hour on/8 hour off cycle, two alternates are
recognized:
- Go to a shorter operational day but lengthen the days of
test proportionally
— Use up to 20 percent wort /80 percent off for a propor-
tionally shorter operational day
2. Sampling points must be appropriately adjusted in any alternate
sampling plan.
g. Application of Test Waters: The application of test waters is
designed to provide information on performance under both normal and
stressed conditionsi it should be the same or equivalent to the
following:
1. a. Nalogenated Resins or Units (Non-iodine based) —-
First 50% of test period: Test Water 1 (General)
Last 50% of test period: Test Water 2 (Chal1enge)
(pH — 9.0 0.2)
b. Iod.thated Resins or Units —
First 50% of test period: Test Water 1 (General)
Next 25% of test period: Test Water 2 (Challenge)
(pH — 9.0 0.2)
I.ast 25% o? test pe.riod: Test Wat•r 2 (Challenge)
(but with pH — 5.0 0.2)
2 __Ceramic-Candleaor Units —
Firèt.6 days of testing: Test Water 1 (General)
N-l6

-------
Last 4—1/2 days of testing: Test Water 3 (Challenge)
3. Ultraviolet (U.V.) Units —-
First 6 days of testing: Test Water 1 (General)
Last 4—1/2 days of testing: Test Water 4 (Challenge)
h. Analyses and monitoring:
1. Microbiological sampling and analysis shall be conducted of the
specified influent and effluent sampling points during each
indicated sampling period.
2. Test Water Monitoring: The specified parameters of the various
test waters (see Section 3.3) wii.l be measured and recorded at
each microbiological sampling point; the specified parameters
will be measured at least once on non—sampling days when the
units are being operated.
3. Background chemical analyses of influent water s iL1.
ducted at least once at the start of eaci- tert- : ri.. ‘,
determine the concentration of the U.S. EPA primary inorganic
contaminants, secondary contaminants and routine water para-
meters, not otherwise covered in the described test waters.
4. In addition, quality assurance testing shall be conducted for
the seed bacteria under environmental conditions on the first
and last days of testing to make sure that there is no signifi-
cant change over the test day. Populations will be measured
(for example, as dispersed in the supply tank) at the beginning
and end of the test day to detect possible incidental effects
such as proliferation, die—off, adsorption to surfaces, etc.
Relatively stable bacterial seed populations are essential to
an acceptable test program.
5. When a unit contains a halogen or silver, the active agent
residual will be measured in the effluent at each mi.crobiologi-
cal test (sampling) point.
6. Silver will additionally be measured three times in the efflu-
ent as specified in Section 3.5.l.e.
i. Neutralization of Disinfection Activity Iamediately after col-
lection, each test sample must be treated to neutralize residual
disinfectant. For halogen- and silver—based disinfectants this may
be done by addition of thioglycollate—thiosulfate neutralizer
solution (Chambers, et al ., , J. Amer. Water Works Assoc., 54:208—216,
1962). This solution should be prepared daily. All results are
invalid unless samples are neutralized issaediately upon collection.
j. Special Provisions for Ceramic Candles or Units:
N- 17

-------
1. Provisions for slow flow: Ceramic units may be subject to
clogging and greatly reduced flow over the test period. An
attempt should be made to maintain manufacturer rated or
claimed flow rates, but even at reduced flows the sampling
program set forth in Section 3.5.1.6.2 shall be maintained.
2. Cleaning of ceramic units: Units should be cleaned acecrding
to manufacturer’s directions. Two cleanings should occur
during the period of test (in order to prove the unit’s
durability through the cleaning procedure). owever, near the
time of microbiological sampling, the units should not be
cleaned until after the sampling. Further, no anti-microbial
chemical (for cleaning or sanitizing) may be applied to the
units during the test period unless the manufacturer specifies
the same as part of routine maintenance.
k. Balogenated units or CLV. units with mechanical filtration processes
separate from the microbiological disinfection components shall have
the mechanical filtration components replaced or serviced when
significant flow reduction (clogging) occurs in accordance with the
manufacturer’s instructions in order to maintain the test flow rate.
Units with non—removable mechanical filtration components will be
run until flow is below that considered acceptable for consumer
convenience. (If premature clogging presents a problem, some
specialized units may require a customized test plan.)
1. Special Provisions for Ultraviolet (U.V.) Units;
I. The units will be adequately challenged by the prescribed test
waters; consequently they will be operated at normal intensity.
However, where the U.v. treatment component is preceded by
activated carbon treatment, the output of the U.V. lamp shall
be adjusted electronically, such as by reducing the current to
the lamp or other appropriate means, to be just above the alarm
point. This option shall be available for use under other U.V.
configurations, at the choice of the persons responsible for
testing, as an alternative to the use of the C LV. absorbent,
p—bydroxybensoic acid.
2. Fail/safe: Units will provide and will be tested for fail/safe
warnings in the event of water quality changes or equipment
failures which may interfere with its microbiological purifica-
tion fnnqtJ i , .
3. Cleaning: -nanufacturer’s guidance with respect to cleaning
- will be followed.
9.5.2 •Procedur-ss :N ..pl ed Units
a. General: The basic procedures given in Section 3.5.1 Mall be used
with necessary adaptations to allow for the specific design of the
u-l a

-------
unit. In any event, the testing procedures shall provide a test
challenge equivalent to those for plumbed-in units.
b. Test conditions and apparatus should be adapted to reflect proposed
or actual use conditions in consultation with the manufacturer,
including flow rate and number of people to be served per day. In
some cases variable flow or other non-standard conditions may be
necessary to reflect a worst-case test.
3.5.3 Acceptance and Records
3.5.3.1
To qualify as a microbiological water purifier, all three productzon
units of a type must continuously meet or exceed the reduction requirements of
Table 1, within allowable measurement tolerances for not more than ten percent
of influent/effluent sample pairs, defined as follows:
Virus: one order of magnitude
Bacteria: one order of magnitude
Cysts : one/half order of magnitude
The geometric mean of all microbiological reductions must meet or exceed
the requirements of Table 1. An example is given as follows:
— Unit: iodinated resin.
— Number of sample pairs over the completed test program:
10 per unit — 3 units 30.
— NSber of allowable sample pairs where log reduction is insuffi-
cient: 10% of 30 a 3 sample pairs.
— Allowable minimum log reductions in these 3 pairs:
- Bacteria — S log
- Virus - 3log
— Cyst — 2—1/2 log
— Conclusion: If the geometric mean of all reductions meets or
exceeds the requirements of Table 1, the indicated insufficient
sample paira will be allowed.
3.5.3.2 Records
N-l 9

-------
All pertinent procedures and data shall be recorded in a standard format
end retained for possible review until the report of results has been com-
pletely accepted by review authorities, in no case for less than a year.
3.5.3.3 Scaling Up or Down
Where a manufacturer has several similar units using the same basic
technology and parallel construction and operation, it may sometimes be
appropriate to allow the test of one unit to be considered representative of
others. Where any serious doubt exists, all units of various sizes may
require testing. A rule of three” is suggested as a matter of judgment.
Scaling up to three times larger or on—third, based on the Bize of either the
test unit or of its operative element, may be allowed. However, for LIV units,
any size scale—up must be accos ,anied by a parallel increase in radiation
dose.
3.5.3.4
Where silver or some other chemical is used in the unit, concentrations
in the effluent water must meet any National Primary Drinking Water Maximum
Contaminant Level (MCL), additional Federal guidelines, or otherwise must not
constitute a threat to health where no MCI. exists.
N-20

-------
APPENDIX N-i
SUM1 tARY FOR BASrS OF STA1 IDARDS AND TEST WATER PARAMETERS
A. Microbiological Reduction Requirements
1. Bacteria
Current standards for the microbiological safety of drinking
water are based on the presence of coliforu bacteria of which
Kiebsiella is a member. Members of the genus Klthsieila are also
potential pathogens of man (Vlassof, 1977). Klebsiella terrigena is
designated as the test organism since it is coum only found in
surface waters (Izard, et al., 1981).
Experience with the use of coliform bacteria to estimate the
presence of enteric bacterial pathogens in drinking water as per-
formed over the last 75 years indicates a high degree of reliabil-
ity. Required testing of more than one bacterial pathogen appears
un ustified since viral and Ciardia testing will be required.
Enteric viruses and Clardia are known to be more resistant to cormeon
disinfectants than enteric bacterial pathogens and viruses are more
resistant to removal by treatments such as filtration. Thus, any
treatment which would give a good removal of both virus and Giardia
pathogens would most likely reduce enteric bacteria below levels
considered infectious (Jarroll, et a).., 1981; L.iu, et al., 1971).
The c ncentration of coliforrn bacteria in raw sewage is approx-
imately 10 /100 ml. C ncentrations in polluted stream waters have
been found to exceed 10 per 100 ml (Culp, et al., 1978, Table 10).
Based on the over 1O /1O0 ml concentrations observed in highly
polluted stream water and a target effluent concentration of less
than 1/100 ml, a 6 log reduction is recoamended.
2. Virus
In the United St 9 es oncentrations of enteroviruses are esti-
mated to range from 10 -10 /liter in raw sewage (Farrah and Schaub,
1971). Based on this observation it is estimated that 1 natura
waters contaminated with raw sewage may contain from 10 to 10
entaric viruses per liter: - - -
There are currently no standards for viruses in drinking water
in the United States. However, EPA has proposed a non—enforceable
health—based recosmended maximum contaminant level (R .) of zero
for viruses (EPA, 1985). Several individuals and organizations have
developed guidelines for the presence of viruses in drinking water
and various experts have propàsed standards (WHO, 1979, 1984; Berg,
1971; Melnick, 1976). It t as generally been felt that drinking
N- 21

-------
water should be free of infectious virus since even one virus is
potentially infectious and suggested standards are largely based on
technological limits of our detection methodology. Guidelines
suggested by the World Health Organization (1984) and others
recommend that volumes to be tested be in the order of 100—1,000
liters and that viruses be absent in these volumes.
Assuming a target effluent level of less than one virus in 100
liters of water and a concentration of 10 enteric viruses in 100
liters of sewage-contaminated waters, the water purifier units
should achieve at least 4 logs of virus removal.
The relative resistance of enteric viruses to different dis-
infectants varies greatly as ng the enteric viruses and even among
members of the sane group (i.e., enteroviruses). For example, while
12 coliphaqe is one cf the most resistant viruses to inactivation by
chlorine it is one of the most susceptible to inactivation by ozone
(Harakeb and Butler, 1984). Ionic conditions and pH can also affect
the relative resistance of different viruses to a disinfectant
(EngeThrecht, et al., I9BO). On this basis it is felt that more
than one enteric virus should be tested to ensure the efficacy of
any disinfection system. Poliovirus type 1 (Strain LSc) was chosen
as one of the test viruses because it has been extensively used in
disinfection and environmental studies as representative of the
enterovirus family. It is recognized that it is not the most
resistant virus to inactivation by chlorine, but is still resistant
enough to serve as a useful indicator. Rotavirus is selected as the
second test enteric virus since it represents another group of
enteric viruses in nucleic acid composition and size. It is also a
major cause of viral gastroenteritis and has been documented as a
cause of water borne gastroenteritis (Gerba, et al., 1985). The
human rotavirus or the similar Simian rotavirus may be used in the
test gjrocedure. A net 4-log reduction for a joint challenge of
1 x 10 /L each for poliovirus and rotavirus is recommended.
3. Cysts (Protozoan)
Over the-past several years, giardiasis has consistently been
one of the most frequently reported waterborne diseases transmitted
by drinking water in the united States (Craun, 1984). EPA has
proposed a MCL of rero for Giardia (EPA, 1985). Its occurrence has
generally been associated with treatment deficiencies including
either inadequate or no filtration. Siardiasis has not been known
to occur from drinking -water - produced by well-operated filtration
treatment plants.. be Walle, ret al.S41984), in a study of filtration
treatment plant efficiencies, cited percent removals for Giardia in
pilot plant teats as follows:
- bpf&fLttzation withcoagvzaatio&-sedimefltattofl: 96.6-99.9%;
- ? t44 ltratiosvwith roagutat1oñ .95.3.49.9%.
N - i l

-------
From this research and from the lack of Giardia cases in
systems where adequate filtration exists, a 3-log (99.9%) reduction
requirement is considered to be conservative and to provide a
comparable level of protection for water purifiers to a
well—operated filtration treatment plant.
Data on environmental levels for Cysts in natural waters is
limited because of the difficulties of sampling and analysis.
Unpublished data indicate very low levels from less than lit to less
than lO/L. Here a 3-log reduction would provide an effluent of less
than 1/100 L, comparable to the recomeended virus reduction require-
ments.
Either Clardia lairtblia or the related organism, Giardia niuris ,
which is reported to be a satisfactory test organism (Hoff, et al.,
1985), may be used as the chal’enge organism. Tests will be con-
ducted with a challenge of 10 organisms per liter for a 3—log
reduction.
Where the treatment unit or component for cysts is based on the
principle of occlusion filtration alone, testing for a 3-log reduc-
tion of 4—6 micron particles or spheres (National Sanitation Founda-
tion Standard 53, as an example) is acceptable. Difficulties in the
cyst production and measurement technologies by lesser-equipped
laboratories may require the use of such alternative tests where
applicable.
B. Microbiological Purifier Test Procedures
1. Test Waters
a. The general test water (test water #1) is designed for the
normal, non—stressed phase of testing with characteristics that
may easily be obtained by the adjustment of many public system
tap waters.
b. Test water #2 is intended for the stressed phase of testing
where units involve halogen disin.fectants.
1. Since the disinfection activity of some halogens falls
with a rising pH, it is important to stress test at an
elevated pH. The recoended level of 9.0 0.2, while
exceeding the recomeended secondary level (Environmental
Protection Agency, 1984) is still within a range seen in
some natural waters (Environmental Protection Agency,
1976). However, for iodine—based units, a second stress-
ful condition is provided —— a pH of 5.0 0.2 since
current information indicates that the disinfection
activity of iodine falls with a low pH (National Research
Council, 1980). While beneath the reco nended secondary
level (Environmental Protection Agency, 1984) a pH of 5.0
N-2 3

-------
is not unusual. in natural waters (Environmental Protection
Agency, 1976).
2. Organic matter as total organic carbon ( VC) is known to
interfere with halogen disinfection. While this TOC is
higher than levels in many natural waters, the designated
concentration of 10 mqfL is cited as typical in stream
waters (Cuip/Wesner/CuIp, 1978).
3. High concentrations of turbidity can shield microorganisms
and interfere with disinfection. While the recosuiended
level of not less than 30 NTU is in the range of turbidi-
ties seen in secondary wastewater effluents, this level is
also found in many surface waters 1 especially during
periods of heavy rainfall and snow melt (Culp/Wesner/Culp,
1978).
4. Studies with Giardia cysts have shown decreasing halogen
disinfection activity with lower temperatures (Jarroll,
et al. , 1980), 4 C, a cnl ,ion low temperature in many
natural waters, Is rec ended for the stress test.
5. The amount of dissolved solids (TDS) may impact the
disinfection effectiveness of units that rely on displace-
able or exchange elements by displacement of halogens or
resins, or it may interfere with adsorptive processes.
While TDS levels of 10,000 mg/L are considered unusable
for drinking, many supplies with over 2,000 mg/L are used
for potable purposes (Environmental Protection Agency,
1984). The recos iended level of 1,500 mg/L represents a
realistic stress challenge.
c. Test water *3 is intended for the stressed phase of testing of
ceramic filtration candles or units with or without silver
impregnation.
1. Since viruses are typically eluted from adsorbing media at
high pHe (Enviro ental Protection Agency, 1978) it may be
concluded that a high pH will, provide the most stressful
testing for a ceramic-type unit; consequently, the high
natural water pH of 9 • 0 is reco ended.
2. Expert opinion also holdB that organic material will
interfere with adsorption of viruses. Thus, a high total
organic carbon level of not less than 10 mg/L is recom—
mended.
3. Thrbidity may enhance the .entrapment and removal of
microorganimsa but it elso - may stimulate ‘short—
circuiting’ through some units. A turbidity level of
- 30 NTU will provide stress at time of sampling but the
N-24

-------
non—sampling level of 0.1—5 NTU will allow routine opera-
tion of units.
4. Expert opinion holds that low water temperatures and high
TDS would most likely .nterfere with virus reduction by
adsorption; consequently, a 4 C temperature and 1,500 nig/L
TDS are recor wtended.
d. Test water *4 is intended for the stressed phase of testing for
ultraviolet (UV) units.
1. !n general, high TOC, turbidity and TDS and low tempera-
ture are considered most stressful far UV, and the in-
dicated challenge levels are the sane as for test
water #2.
2. The pH is not critical and may range from 6.5 to 8.5.
3. In order to test the tJV units at their most vulnerable
stage of operation, a color challenge (light absorption at
254 nm) is to be maintained at a level where liv light
intensity is just above the unit’s low intensity warning
alarm point. However, an alternate to the absorption
challenge is provided through adjusting the light intensi-
ty output of the l iv lamp electronically by reducing
current to the lamp, or other appropriate means, to be
just above the alarm point; this approach would be
particularly necessary where the liv lamp is preceded by
activated carbon treatment.
e. Test water #5 is intended for the stressed leaching tests of
units containing silver. Low pH, TOC, turbidity, and TDS and
higher temperature are felt to be the characteristics associ-
ated with increased leachabi].ity. The reco ended pH of
5.0 .2, while being beneath the recon ended secondary range
of 6.5- 8.5 (Environmental Protection Agency, 1984) is still
found in some natural waters.
2. Test Procedures
The plan for testing and sampling is designed to reveal unit
performance under both normal and “stressed” operating conditions.
The stressed phase would utilize a set of water quality and opera—
t.tons conditions to give the units a realistic worst case challenge.
Testing plans for a specific model might involve modifications to
the rec ended plan; more samples could be taken and analyzed; more
units could be studied. The principle of demonstrating adequate
performance even under realistic worst case conditions should be
maintained and the final selected test procedures should be agreed
as between investigators and reviewers or regulators.
N—2 5

-------
While some aspects of the testing procedures have been utilized
in actual experiments, the proposed protocol has not been verified
or utilized for the various units that may be considered. Conse-
quently, investigators and users of this protocol may find reasons
to alter some aspects through their practical experience; needed
changes should be discussed and cleared with involved reviewers/—
regulators.
N-26

-------
REFERENCES :
Berg, G. Integrated approach to the problem of viruses in water. J. ASCE,
Sanit. Eng. Div. 97:867—882, 1971.
Cuip/Wesner/Cuip. Guidance for planning the location of water supply intakes
downstream from municipal wastewater treatment fac 1aties. EPA Report, Office
of Drinking Water. Washington, DC, 1978.
Craun, G. P. 1984. Waterborne outhreaks of giardiasis: Current status. In:
Giardia and giardiasis. D. L. Erlandsen and E. A. Meyer Eds., Plenum Press,
New York, pp. 243—261, 1984.
DeWalle, F. B.; .Y. Engeset, Lawrence, W. Removal of Ciardia laxnblia cyst by
drinking water treatment plants. Report No. EPA- .600/52—84-069, Office of
Research and Development, Cincinnati, 08, 1984.
EngeThrecht, R. S., et al. Comparative inactivation of viruses by c}-.orine.
Appi. Environ. Microbiol. 40:249-256, 1980.
Environmental Protection Agency. Quality criteria for water. Washington, DC,
1976.
Environmental Protection Agency. National secondary drinking water
regulati.ons. EPA—570/9—76—000, Washington, DC, 1984.
Environmental Protection Agency. National primary drinking water regu1at .ons;
synthetic organic chemicals, inorganic chemicals and microorganisms; Proposed
rule. Federal Register, Nov. 13, 1985.
Farrah, S. R., and S. A. Schaub. Viruses in wastewater sludges. In: Viral
Pollution of the Environment, C. Berg, Ed. CRC Press, Boca Raton, F1or .da.
pp. 161—163, 1983.
Cerba, C. P.; Rose, J. B.; Singh, S. N. Waterborne gastroenteritis and viral
hepatitis. CRC Critical Rev. Environ. Contr. 15:213—236, 1985.
Marakeh, N.; Butler, N. Inactivation of human rotavirus, SA—il and other
enteric viruses i effluent by disinfectants. J. Hyg. Camb. 93:157—163, 1984.
Hoff, J. C. 1 Rice, E. W. ; Schaefer, F. W. Coi arison of animal infectivity
and excystation as measures of Giardia nuns cyst inactivation by chlorine.
Appl. Environ. Iticrobjol 50:1115—1117, 1985.
Izard, D.; Farragut, C.;Gavini, F.; Kersters, K.; DeLey, J.; Leclerc, H.
Klebsiella terrigena , a new species from water and soil. - Intl. J. Systematic
Bacteriol. 31:116—127, 1981.
.lakubowski, W. Detection of Giardia cysts in drinking water. In: Giardia
and Giardiasis, Erlandsen, S. L.; Meyer, E. A. Eds., Plenum Press, NY.
pp. 263—286, 1984.
N-27

-------
Jarroll, E. L., Bingham, A. K.; Meyer, E. A. Giardia cyst destruction:
Effectiveness of six sma1l—q iantity water disinfection methods. Am. .3. ‘Prop.
lied. 29:8—11, 1980
Jarroll, E. L.; Binghazn, A. K.7 Meyer, E. A. Effect of chlorine on Glardia
cyst viability. App I. Environ. Microbiol. 43:483—487, 1981.
Liu, 0. C., et al. Relative resistance of 20 human enteric viruses to free
chlorine in Potomac River water. Proceedings of 13th Water Quality Conference
Snoeyink, V.; Griffin, V. Eds., pp. 171—195, 1971.
Melnick, J. I .. Viruses in water. In: Viruses in Water Berg, C.;
Bodily, H. L.; Lennette, E. H.; Melnick, J. L.; Metciaf ‘P. C., Eds. Amer.
Public filth. Assoc., Washington, IDE, pp. 3—11, 1976.
National Research Council. The disinfection of drinking water, In: Drinking
Water and Health, Volume 2. Washington, DC, pp. 5—137, 1980.
National Sanitation Foundation. Drinking water treatment units: Health
effects. Standard 53. Ann Arbor, MI, 1982. -
Viassoff, L. ‘P. Klebsiella . In: Bacterial Indicators/Health Hazards
Associated with Water Hoadley, A. W.; Dutka, B. J., Eds. American Society for
Testing and Materials, Philadelphia, PA. pp. 275—288, 1977.
World Health Drganization. Human Viruses in Water, Technical Support
Series 639, World Health Organization, Geneva, 1979.
World Health Organization. Guidelines for Drinking Water Quality. Volume 1.
Reconm endations. World Health Organization, Geneva, 1984.

-------
APPENDIX N—2
LIST OF PARTICIPANTS: TASK FORCE ON GUIDE STANDARD AND PROTOCOL FOR
TESTING MICROBIOLOGICAL WATER PURIFIERS
Stephen A. Schaub, Chairman — — U.S. Army Medical Bioengirteering Research and
Developnent Laboratory (tJSAMBRDL), Fort Detrick, Maryland 217C 1, FTS:
8/935—7207 —- Come: 331/663—7207.
Frank A. Bell, Jr., Secretary — — Criteria and Standards Division, Of lice of
Drinking Water (WH—550), Environmental Protecti.on Agency, Washington,
D.C. 20460, Phone: 202/382—3037.
Paul Berger, Ph.D. - - Criteria and Standards Division, Office of Drinking
Water (WH-550), Environmental Protection Agency, Washington, D.C. 20460,
Phone: 202/382—3039.
Art Castillo —— Disinfectants Branch, Office of Pesticide Programs CTS—767C0,
Environmental Protection Agency, Washington, D.C. 20460, Phone: 703/557—
3695.
Ruth Douglas —— Disinfectants Branch, Office of Pesticide Programs (TS—767C),
Environmental Protection Agency, Washington, D.C. 20460, Phone: 703/557—
3675.
Al Dufour — — Microbiology Branch, Health Effects Research Laboratory,
Environmental Protection Agency, 26 W. St. Clair Street, Cincinnati, Ohio
45268, Phone: FTS: 8/684—7870 — — Comet: 513/569—7870.
Ed Geldreich — - Chief, Microbiological Treatment Branch, Water Engineering
Research Laboratory, Environmental Protection Agency, 26 W. St. Clair
Street, Cincinnati, Ohio 45268, Phone: flS: 8/664-7232 —— Coneti:
513/569—7232.
Charles Gerba —e Associate Professor, Department of Microbiology and
Inwtunology, University of Arizona, Tucson, Arizona 85721, Phone:
602/621—6906.
John Hoff — — Microbiological Treatment Branch, Water Engineering Research
Laboratory, Environmental Protection Agency, 26 W. St. Clair Street,
Cincinnati, Ohio 45268, Phone: FTS: 8/684—7331 — — Come: 513/569—7331.
Art Kaplan — Office of Research and Development (PD—Eel) Environmental
Protection Agency, Wa shington, D.C. 20460, Phone: 202/382—2583.
Bala Xrishnan —— Office of Research and Development (RD—681) Environmental
Protection Agency, Washington D.C. 20460, Phone: 202/382—2583.
John Lee —— Disinfectants Branch, Office of Pesticide Programs (TS-767C)
1 4—29

-------
Environmental Protection Agency, Washington, D.C. 20460, Phone:
703/557—3663.
Dorothy Portner — — Disinfectants Branch, Office of Pesticide Programs
(TS-767-C), Environmental Protection Agency, Washington, D.C. 20460,
Phone; 703/557—0484.
Don Reasoner — Microbiological Treatment Branch, Water Engineering Research
Laboratory, Environmental Protection Agency, 26 W. St. Clair Street,
Cincinnati, Ohio 45268, Phone: 312/654—4000.
P. Reguanthan (Regu) —— Everpure, Inc., 660 N. Blackhawk Drive, Westmont,
Illinois 60559, Phone: 312/654—4000.
David Stangel —— Policy and Analysis Pranch, Office of Cou liance Monitoring,
Environmental Protection Agency, Washington, D.C., Phone: 202/382-7845.
Richard Tobirt —— Monitoring and Criteria Division, Environmental Health
Center, Department of Health and Welfare of Canada, Tunney’s Pasture,
Ottawa, Ontario, KIA 0L2, Canada, Phones 613/990—8982.
N-30

-------
APPENDIX N-3
RESPONSE BY REVIEW SECOMMI1’TEE TO PUBLIC COMNENTS ON GUIDE STANDARD
AND PROTOCOL FOR TESTING MICROBIOLOGICAL WATER PURIFIERS
A. Recommendation for the use of Ciardia iambus cysts as a replacement for
Giardia nuns cysts as the protozoan cyst test organisms.
Recommendation :
The subcommittee concurs with the recommendation and further endorses the
use of Giardia lamblia as the preferred cyst test for evaluation of all
treatment units and devices. Obviously the use of the protozoan orga—
nis s of actual health concern in testing is most desirable. Anyone
finding the Giardia iambus strain feasible for testing and cost—
effective to work w .th is encouraged to use same instead of Giardia
nuns .
B. Substitution of 4—6 micron bead or particle tests as an alternate option
instead of the Giardia cysts for evaluating devices that rely strictly on
occlusion filtrat .on for microbiological removal: Several conunenters
criticized the use of beads or particles (e.g., A.C. fine dust) and
recommended only use of live Giardia cysts for performance tests.
Discuss3.on :
The subcos ittee recognizes and favors the use of the natural human
parasite, Giardia lambl .a , but was not aware of any convincing se .ent .fic
data which would disallow the optional use of testing with beads or
particles for units or devices using only occlusion filtration to remove
microorganisms. Previous development of the National Sanitation Standard
(NSF) 53 (1982) reqa.iirement for cyst reduction (using 4—6 micron parti-
cles as cyst models) was based on engineering and scientific opi on and
experimental evidence at that time. Specifically, Logsdon used
radioactive cyst.models in the initial phase of a study of removal
efficiencies for diatomaceous earth fi1ters subsequent experiments with
Giardia muris cysts confirmed the effi ,cy of the di omaceous earth
filters. Further studies by Hendricks and Dewalle with Ciardia
lamblia cysts also showed comparable reduction efficiencies for
dxatomaceous earth filters.
l.S.A. Schaub; F.A. Bell, Jr.j P. Bergen C. Gerba J. Hoff;
P. Regunathan; and R.-Tobin. (Includes additional revision pursuant to
Scientific Advisory Panel review (Federal Insecticide, Fungicide, and
denticide Act).)
N- 31

-------
Subsequently confirmatory parallel testing results have been developed
v is-a—vis 4-6 micron particles as compared to Giardia lamblia cysts.
Specifically, two( 4 nits listed by NSF for cyst reduction (using 4—6
micron particles) have also been tested and li d for 100% efficiency
reduction (using Giardia lamblia cysts) by Hibler
1. Everpure Model QC4-SC
2. Royal Soulton Model P303.
Again we prefer the use of the human pathogen, Giardia iambus ; however,
no experimental data has been provided regarding the lack of validity or
of failure in previous tests utilizing beads or particles of 4—6 microns.
In most cases the bacterial or viral challenges to occlusion filters ill
represent a greater problem in terms of microbiological reduction
requirements than viii cysts. Therefore, without substantiation of
deficiencies, the use of 4—6 micron beads or particles is considered to
be as feasible as the use of live cysts for routine performance testing
of water filtration (occlusion) devices.
Reco endation :
Recoa end retaining the optional use of 4—6 micron particles or beads for
cyst reduction testing in occlusion filtration devices only.
References :
(1) Logsdon, C. S., et al. Alternative Filtration Methods for Removal
of Giardia Cysts and Cyst Models, JAWWA, 73(2)111—118, 1981.
(2) Logsdon, C. S.; Hendricks, D. W., et al. Control of Giardia Cysts
by Filtration: The Laboratory’s Rose. Presented at the AWWA Water
Quality Technology Conference, December, 1983.
DeWalle, et al. Removal of Giardia lamblia Cysts by Drinking Water
Treatment Plants, Grant No. R806127, i eport to Drinking Water
Research Division, U.S. EPA (ORD/MERL)., Cincinnati, Ohio.
National San.ttata.on ioun at.ton, List.ij g or- prinicLng Water Treatment
Units, Standard 53. May, 1986. -
Ribler, c. F, An Evaluation àf Filters i,n the Removal of Ciardia
lamblia . Water Technology, pp. 34—36 July, .1.984.
C. Alternate assay techniques for cyst tests (Jensen): Proposed alterations
in cyst tests include a different method for separating cysts from fecal
material and an assay method involving the counting of trophozoites as
well as intact cysts. Both alterations have been used by Bingham, et al.
(Exp. Pa.rasito1,,47:284—29 , 1979). -
Recome endation :
N- 32

-------
These alterations appear to be reasonable laboratory procedures, support-
ed by a peer—reviewed article and will be included in the Report as
options for possible development and use by interested laboratories.
D. The use of pour plate techniques as an option for Kiebsiella terrigena
bacteria analyses.
Recorrniendation :
The pour plate technique adds a heat stress factor to the bacteria which
constitutes a possible deficiency. However, it is a recognized standard
method and probably viii. not adversely affect the Kiebsiella terrigena .
Consequently, it will be added to the Report as one of the acceptable
techniques.
E. Option of using Escherichia coli in lieu of Kiebsiella terrigena for the
bacterial tests.
Discussion :
Appendix N-i, Section A.i. of the Guide Standard and Protocol sets forth
the basis for selection of K. terrigena as the test bacteria. The
selection was made along pragmatic line emphasizing the occurrence of K.
terrigena in surface waters and that It would represent the enteric
bacteria. It was also pointed out that the tests with virus and Giardia
were expected to be more severe than the bacterial tests. For comprehen-
siveness, bacterial tests were included in the protocol but were not felt
to be as crucial as the virus and Giardia tests.
E. coil , or any number of other generally accepted indicator bacteria,
could be used for the test program if they were shown to have good
testing and survival characteristics (equivalent to K. terrigena ) by the
interested research laboratory.
Reconese ndat ion :
The intent of the Qzide Standard and Protocol is to provide a baseline
program subject to modification when properly supported by an interested
laboratory. Consequently, any - laboratory could propose and with proper
support (demonstrating challenge and test equivalency to K. terrigena )
use Escherichia coli or one of the other enteric bacteria. This idea
will be included in revised working in Section 1.2.2, General Guide.”
F. Performance requirements for Giardia -cysts and virus in relation to the
EPA-Reco nded Maximum Contamination Levels (RZ4CLs) of zero.
Discussion :
The P.$CLs of xero for Giardia and viruses which have been proposed by EPA
are health goals. They are no enforceable standards since to assure the
presence of “no organisms” would require an infinite sample. The
N- 33

-------
rationale for the reco m ertded performance requirements for Giardia cysts
and virus is set forth in Sections A.2 and A.3 of Appendix A. We feel
that these requirements together with the application of realistic worst
case test conditions will provide a conservative test for units resulting
in treated effluent water eqi.iivalent to that of a public water supply
meeting the microbiological requirements and intent of the National
Primary Drinking Water Regulations.
Recor iendation :
Retain recommended performance (log reduction) requirements for cyst and
virus reduction.
C. Rotavirus and its proposed assay: One commenter states that the rota—
virus tests are impractical because Amirthara ah (3. AWWA, 78(3);34-49,
1976) cites “no satisfactory culture procedures available for analysis of
these pathogens and, therefore, monitoring would not be feasible.”
Discussion :
Section 3.4.1.2, Virus Tests” of the Report, presents means for cul-
turing and assaying rotaviruses. This means for doing the rotavirus
tests are available and are practical for application in the laboratory .
Dr. Am .rtharajah was referring to the field collection, identification in
the presence of a wide variety of microorganisms, and quantification as
not being “satisfactory. • Laboratory analysis of rotaviruses is practi-
cal but their field monitoring may not yet be feasible.
Further, the selection of both poliovirus and rotavirus as test viruses
was necessitated by the fact that the surface adsorptive properties and
disinfection resistance of the various enteric viruses have been shown to
differ significantly by virus group and by strains of a specific virus.
While all enteric viruses and their strains could not be economically
tested, it was determined by the task force that at least two distinctly
different virus types should be tested to achieve some idea of the
diversity of remoyal by the various types of water purifiers. Polio and
rota viruses have distinctly different physical and chemical charac-
teristics representative of the viruses of concern. Polioviruses are
small Bingle stranded RNA viruses with generally good adsorptive proper-
ties to surfaces and filter -media while rotaviruses -are over twice as
large, are double stranded RNA and in some athdiea have been found to
possess less potential for adsorption onto surfaces or filter media.
These two viruses also have been demonstrated to have somewhat different
4isinfect.Lon kinetics,
Recome ,endat.ion :
Retain the rotavirus test requirements.
.D .fiz ition of miQrthjQl gica1 - iwtr puxifier zOne ieneral ‘cosment
x qu.B ted redefin.t.tjo t ased ¶1.eck of any ithus moval requirement
N-34

-------
in the EPA primary drinking water regulations, so that no virus reduction
requirement should be included. Also, it was claimed that the separation
of purifiers from non—purifiers would be a “disservice to consumers and
other users. ”
Discussion :
Viruses are recognized in the EPA regulations vis-a—vis a proposed recom-
mended maximum contaminant level of zero. Since virus monitoring for
compliance with a possi.ble ?tCL is not yet feasible, a treatment require-
ment is necessary. Virus control will be considered in the Safe Drinking
Water Act filtration and disinfection treatment regulstions. The reduc-
tion of viruses by treatment is discussed by Amsrtharajah (J. AWWA,
78:3:34—49, 1986).
With respect to consumers and other users, we feel that the current
definition is appropriate and necessary. The average consumer cannot be
expected to know the difference between viruses, bacteria and cysts, or
when a raw water will or will not contain any of these organisms. In
order to protect the average consumer, the subject units either alone or
with supplementary treatment, should be able to cope with all of the
specified organisms.
Recommendation :
Retain the current definition for microbiological water purifier.
I. Coverage of units: Several comments related to the coverage of units.
These questions are addressed individually as follows:
1. Ultraviolet units that are used for supplemental treatment of water
from public water system taps would not be covered. We agree that
such units are not covered and parenthetical language has been
included in Section 1.3.2.3 to clarify this point.
2. A special status should be given to units which remove Giardia and
bacteria but not virus. Specifically, the meaning of Section 1.2.4,
Nsxceptionaga was addressed. The “Exceptions” section was specif-
ically developed to relate to the problem of public water systems
having disinfection but no filtration on a surface supply. Cysts
alone have been found to survive disinfection treatment and could be
present in such treated waters. In this case an effective cyst
filter serves an independent, beneficial purpose and should not be
required to be a microbiological water purifier. However, such a
-unit should not be used as sole treatment for untreated raw water.
Additional parenthetical language has been added to section 1.2.4.
3,.. Vie entire treatment unit or system should be tested, not just a
single ccziponent. We agree but believe that it is sufficiently
cle at without providinq additional language.
P1-35

-------
4. The protocol should be expanded to cover units for the reduction of
TCE, EDB and other chemical pollutants. We felt that the introduc-
tion of non—microbiological claims to the standard would make it
large, unwieldy and duplicative of an existing third—party standards
and testing program see Section 1.2.5).
.J. Alleged preference of National Sanitation Foundation (NSF) over other
laboratories for conducting the microbiological water purifier testing
protocol. The cossnent indicated that we were giving NSF preferential
treatment “to the detriment of other laboratories well qualified to
perform the required protocol.
Discussion :
We have made appropriate references to existing standards (#42 and #53)
developed by the NSF standards development process. Standard 53, the
health effects standard, was developed by a broadly based Drinking Water
Treatment Units Coss .ittee, including representatives from local, State
and Federal health and environmental agencies, universities, professional
and technical associations, as well as water quality industry
representatives. It as adopted in 1982 and the only test from it
utilized in our Report has been substantiated as descrthed in Part S of
this “Response.
Nowhere in our report have we advocated NSF (or any other laboratory) as
the prime or only laboratory for implementing TM the required protocol.”
Reconm endation ;
No action needed.
x. Instruction concerning effective lifetime. One comeent described an
alternate means for determining lifetime where a ceramic unit is
“brushed to renew its utility and is gradually reduced in diameter. A
gauge is provided to measure diameter and to determine when replacement
is needed.
Recormi endation ,
Where a manufacturer provides a satisfactory mother ” means of determining
lifetime, this should be accepted. Appropriate words have been added to
Section 2.4.1.C.
1.. Ceramic candles should not be cleaned during testing because- some
consumers would not clean them and this would provide the worst case
testa - One coent asserted this point.
Discussion :
There is some truth to this proposition. However, the other approach may
also have validity. Frequent brushing may reduce filtration efficiency.
—N-36

-------
In any event 1 where a manufacturer prescribes filter cleaning and how to
do it, and provides a gauge to determine lifetime, we feel the testing
program is bound to follow the manufacturer’s directions.
Reconniendatjon :
No change needed.
11. Scaling up or down. One comment points out that one or more manufac-
turers may vary size of treatment units by increasing or decreasing the
number of operative units rather than the size of the operative unit.
The comment suggests allowing scaling based on size of operative unit.
RecorTmiendatiorl :
we agree with the comment and have added clarifying words to Sec-
tion 3.5.3.3.
N. Turbidity level of not less that 30 wru” for ceramic candles or units.
One comment states that “Such levels are impossible to utilize in testing
mechanical filtration devices which will clog entirely or require such
frequent brushing as to render the test impossible as a practical
matter.”
Discussion :
We recognized the potential “clogging problems” in Section 3.5.1.a(2)
where the 30 rru water is only to be applied immediately before and
during each sampling event; the non—sampling turbidity level, which will
be applied over 90% of the “on” time, is currently set at no less than
10 NTtT.
Turbidity levels of 30 NTU are couonly found in surface waters during
heavy rainfall or snow melt. Treatment units may be used under these
circumstances, so this challenge level should be retained. However, most
usage will occur under background conditions so the non—sampling
turbidity levels should be 0.1-5 NTU.
Recommendationsz
1. Retain samplthg turbidity level of not less than 30 NTU, and
2. Change non-sa ling turbidity to 0.1-5 N U. Appropriate wording
changes have been introduced in Section 3.5.l.a(2) and in Appen-
dix ti-i, Section 8.
0. Chlorine in test water *5. one comment asserts that chlorine “tends to
increase silver ion leaching activity” and that a high chlorine level
should be included in the silver leaching test: but no reference or
-.vidence, however, ii provided to back this assertion.
N-37

-------
Discussion :
We have no compelling evidence or reason to expect that chlorine will
erthance the leaching’ of silver. However, the prescribed low pH and TDS
levels will provide a clearly severe test for silver leaching.
Recosmendation :
t o change needed.
P. Unnecessary difficulty and expense of test protocols. Several comuents
were made under this general heading. These comments are outlined and
discussed as follows:
1. i ’oo many sampling events are required; sampling of a few units at
start, middle and finish should be satisfactory: The conmu ttee has
carefully laid out the standard and protocol and we feel the minimum
sampling plan must be maintained for the consumers’ health pro-
tection.
2. Three units are too many to study, parallel testing of two units
should be satisfactory; For consumer protection, the Disinfectants
Branch, Office of Pesticide Programs, has traditionally required the
testing of three units. The committee recognizes the additional
cost involved in testing a third unit but feels that this will
provide a minimum level of assurance to prevent infectious disease
and recommends retention of the 3-unit requirement.
3. The protocol requires large tanks and microbiological reseeding on a
daily basis: We feel that the tank size requirements are not
extreme and can be met by an interested laboratory. With respect to
reseeding, it should be pointed out that virus and cyst seeding need
only be conducted immediately before and during the sampling won
period (see Section 3.5.3.b(2fl, equivalent to less that 10% of the
aonN time. This spot seeding for viruses and cysts recognized the
expense and ,difficulty of maintaining large populations of these
organisms. Continuous seeding was provided for bacteria because
they are easier to grow and maintain and might have the capacity to
grow through some units, given enough time and opportunity.
4. Challenge levels of contaminants re too high compared to known
enviroomental conditions and the required log reductions exceed Safe
Drinking Water Act requirements: As explained in a footnote to
Table 1, Section 2, the influent challenges may constitute greater
concentrations than would be anticipated in source waters. These
levels are necessary to test properly for the required log reduc-
tions without having to utilize sample -concentration procedures
which are tjmeflabor intensive and wti.tch may • on their own, intro-
duce ‘quantitative errors to the microbiological assays. ?‘ s men-
tioned in Part I of this paper, the log reductions for bacteria,
virus and Giardia have been suggested for public water system
-N-38

-------
treatment in a paper by Anu.rthara)ah (1986, JAWWA, 78:3:34-49). The
reductions in the #ticrobiological purifier standard are entirely
cc atib1e with the reductions cited for public water supply
treatment.
N- 39

-------