EPA-815-Z-97001
Monday
November 3, 1997
Part III
Environmental
Protection Agency
40 CFR Parts 141 and 142
National Primary Drinking Water
Regulations: Interim Enhanced Surface
Water Treatment Rule Notice of Data
Availability; Proposed Rule
59485
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59486
Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules
ENVIRONMENTAL PROTECTION
AGENCY
40 CFR Parts 141 and 142
P/VH-FRL-5915-4]
National Primary Drinking Water
Regulations: Interim Enhanced Surface
Water Treatment Rule Notice of Data
Availability
AGENCY: U.S. Environmental Protection
Agency (USEPA).
ACTION: Notice of Data Availability;
request for comments; reopening of
comment period.
SUMMARY: USEPA proposed in 1994 to
amend the Surface Water Treatment
Rule to provide additional protection
against disease-causing organisms
(pathogens) in drinking water (59 FR
38832: July 29. 1994). This Notice of
Data Availability summarizes the 1994
proposal; describes new data and
information that the Agency has
obtained and analyses that have been
developed since the proposal; provides
information concerning
recommendations of the Microbial-
Dlslnfectants/Disinfection Byproducts
(M-DBP) Advisory Committee (chartered
in February 1997 under the Federal
Advisory Committee Act) on key issues
related to the proposal; and requests
comment on these recommendations as
well as on other regulatory implications
that flow from the new data and
information. USEPA solicits comment
on all aspects of this Notice and the
supporting record. The Agency also
solicits additional data and information
that may be relevant to the issues
discussed in the Notice. USEPA is
particularly interested in public
comment on the Committee's
recommendations and whether the
Agency should reflect these
recommendations in the final rule. In
addition, USEPA is hereby providing
notice that the Agency is re-opening the
comment period for the 1994 proposal
for 90 days beginning on the date of
publication of today's Notice in the
Federal Register. USEPA also requests
that any information, data or views
submitted to the Agency since the close
of the comment period on the 1994
proposal that members of the public
would like the Agency to consider as
part of the final rule development
process be resubmitted during this
current 90-day comment period unless
already in the underlying record in the
Docket for this Notice.
The Interim Enhanced Surface Water
Treatment Rule (IESWTR) would apply
to surface water systems serving 10,000
or more people. USEPA intends to
promulgate the final rule in November
1998 as required by the 1996
Amendments to the Safe Drinking Water
Act. The Agency plans subsequently to
address surface water systems serving
fewer than 10,000 people as part of a
"long-term" Enhanced Surface Water
Treatment Rule which may also include
additional refinements for larger
systems.
Key issues related to the ffiSWTR that
are addressed in this Notice include the
establishment of a Maximum
Contaminant Level Goal for
Cryptosporidium; removal of
Cryptosporidium by filtration; revised
turbidity provisions; disinfection
benchmark provisions to assure
continued levels of microbial protection
while facilities take the necessary steps
to comply with new disinfection
byproduct standards; sanitary surveys;
inclusion of Cryptosporidium in the
definition of ground water under the
direct influence of surface water; and
inclusion of Cryptosporidium in the
watershed control requirements for
unfiltered public water systems. Other
issues that are discussed include
inactivation of Cryptosporidium, viruses
and Giardia lamblia; uncovered finished
water reservoirs; cross connection
control; and recycling of filter backwash
water and filter-to-waste.
' Today's Federal Register also
contains a related Notice of Data
Availability for the Stage 1
Disinfectants/Disinfection Byproducts
Rule (DBPR). USEPA proposed this rule
at the same time as the IESWTR and
plans to promulgate it along with the
IESWTR in November 1998.
DATES: Comments should be postmarked
or delivered by hand on or before
February 3,1998. Comments must be
received or post-marked by midnight
February 3.1998.
ADDRESSES: Send written comments to
IESWTR NOD A Docket Clerk, Water
Docket (MC-4101); U.S. Environmental
Protection Agency; 401 M Street, SW;
Washington, DC 20460. Please submit
an original and three copies of your
comments and enclosures (including
references). If you wish to hand-deliver
your comments, please call the Docket
between 9:00 a.m. and 4 p.m., Monday
through Friday, excluding legal
holidays, to obtain the room number for
the Docket. Comments may be
submitted electronically to ow-
docket@epamail.epa.gov.
FOR FURTHER INFORMATION, CONTACT: The
Safe Drinking Water Hotline, Telephone
(800) 426-4791. The Safe Drinking
Water Hotline is open Monday through
Friday, excluding Federal holidays,
from 9:00 am to 5:30 pm Eastern Time.
For technical inquiries, contact
Elizabeth Corr or Paul S. Berger,
Ph.D.(Microbiology), Office of Ground
Water and Drinking Water (MC 4607),
U.S. Environmental Protection Agency,
401 M Street SW, Washington DC
20460; telephone (202) 260-8907 (Corr)
or (202) 260-3039 (Berger).
Regional Contacts
Region I. Kevin Reilly, Water Supply
Section, JFK Federal Bldg., Room 203,
Boston, MA 02203, (617) 565-3616
II. Michael Lowy, Water Supply Section,
290 Broadway, 24th Floor, New York,
NY 10007-1866, (212) 637-3830
III. Jason Gambatese, Drinking Water
Section (3WM41), 841 Chestnut
Building, Philadelphia, PA 19107,
(215) 566-5759
IV. David Parker, Water Supply Section,
345 Courtland Street, Atlanta, GA
30365, (404)562-9460
V. Kimberly Harris (micro), Miguel Del
Toral (DBF), Water Supply Section, 77
W. Jackson Blvd., Chicago, IL 60604,
(312) 886-4239 (Harris), (312) 886-
5253 (Del Toral)
VI. Blake L. Atkins, Team Leader, Water
Supply Section, 1445 Ross Avenue,
Dallas, TX 75202, (214) 665-2297
VII. Stan Calow, State Programs Section,
726 Minnesota Ave., Kansas City, KS
66101, (913) 551-7410
VIII. Bob Clement, Public Water Supply
Section (8WM-DW), 999 18th Street,
Suite 500, Denver, CO 80202-2466,
(303) 312-6653
IX. Bruce Macler, Water Supply Section,
75 Hawthorne Street, San Francisco,
CA 94105, (415) 744-1884
X. Wendy Marshall, Drinking Water
Unit, 1200 Sixth Avenue (OW-136),
Seattle, WA 98101, (206) 553-1890.
SUPPLEMENTARY INFORMATION:
Regulated entities. Entities potentially
regulated by the IESWTR are public
water systems that use surface water
and serve at least 10,000 people.
Regulated categories and entities
include:
Public Water System
State Governments
Category
Examples of regulated entities
PWSs that use surface water and serve at least 10,000 people.
State government offices that regulate drinking water.
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This table is not intended to be
exhaustive, but rather provides a guide
for readers regarding entities likely to be
regulated by the IESWTR. This table
lists the types of entities that USEPA is
now aware could potentially be
regulated by the rule. Otfier types of
entities not listed in tiiis table could
also be regulated. To determine whether
your facility may be regulated by this
action, you should carefully examine
the applicability criteria outlined under
Alternatives A and B in § 141.70 of the
proposed rule (59 FR 38832, July 29,
1994).
If you have questions regarding the
applicability of the IESWTR to a
particular entity, contact one of the
persons listed in the preceding FOR
FURTHER INFORMATION CONTACT section.
Additional Information for
Commenters. The Agency requests that
commenters follow the following
format: type or print comments in ink,
and cite, where possible, the
paragraph(s) in this Notice to which
each comment refers. Commenters
should use a separate paragraph for each
method or issue discussed. Electronic
comments must be submitted as a
WPS. 1 or WP6.1 file or as an ASCII file
avoiding the use of special characters
and any form of name or tide of the
Federal Register. Comments and data
will also be accepted on disks in
WordPerfect in 5.1 or WP6.1 or ASCII
file format. Electronic comments on this
Notice may be filed online at many
Federal Depository Libraries.
Commenters who want EPA to
acknowledge receipt of their comments
should include a self-addressed,
stamped envelope. No facsimiles (faxes)
will be accepted.
Availability of Record. The record for
this Notice, which includes supporting
documentation as well as printed, paper
versions of electronic comments, is
available for inspection from 9 to 4 p.m.,
Monday through Friday, excluding legal
holidays at the Water Docket, U.S. EPA
Headquarters, 401 M. St., S.W.
Washington, D.C. 20460. For access to
docket materials, please call 202/260-
3027 to schedule an appointment and
obtain the room number.
Copyright Permission. Supporting
documentation reprinted in this
document from copyrighted material
may be reproduced or republished
without restriction in accordance with 1
CFR 2.6.
List of Abbreviations Used in This
Document
ASCE—American Society of Civil
Engineers
ASTM—American Society for Testing
Materials
AWWA—American Water Works
Association
C—the residual concentration of
disinfectant, mg/L
CDC—Centers for Disease Control
CFE—Combined Filter Effluent
CFR—Code of Federal Regulations
CPE—Comprehensive Performance
Evaluation
CT—the residual concentration of
disinfectant multiplied by the contact
time
DOC—dissolved organic carbon
ESWTR—Enhanced Surface Water
Treatment Rule
FACA—Federal Advisory Committee
Act
gpm/sf—gallons per minute per square
foot
HAAS—Haloacetic acids
(monochloroacetic, dichloroacetic,
trichloroacetic, monobromoacetic,
and dibromoacetic acids)
HAV—hepatitis A virus
hrs—hours
ICR—Information Collection Rule
IESWTR—Interim Enhanced Surface
Water Treatment Rule
IF A—Individual Filter Assessment
IFE—Individual Filter Effluent
ISO—International Standards
Organization
k—the pseudo first-order reaction rate
constant
L—liter
Log Inactivation—logarithm of (N0/N-r)
Log—logarithm (common, base 10)
LTESWTR—Long Term Enhanced
Surface Water Treatment Rule
MCL—Maximum Contaminant Level
MCLG—Maximum Contaminant Level
Goal
M-DBP—Microbial and Disinfectants/
Disinfection Byproducts
mg/L—milligram per liter
mg-min/L—milligram minutes per liter
MMWR—Morbidity and Mortality
Weekly Report
mW-s/cm2—milliwatt seconds per
square centimeter
No—the initial viable concentration of
microorganisms
NPDWR—National Primary Drinking
Water Regulation
NT—the concentration of surviving
microorganisms at time T
NTU—nephelometric turbidity unit
°C—degrees centigrade
PE—Performance Evaluation
pH—negative logarithm of the effective
hydrogen-ion concentration
PV1—poliovirus 1
PV3—poliovirus 3
PWS—Public Water System
RSD—Relative Standard Deviation
SAB—Science Advisory Board
SDWA—Safe Drinking Water Act
T—the contact time, second or minute
TOC—total organic carbon
TTHM—Total Trihalomethanes
TWG—Technical Work Group
UV—ultraviolet
x—log removal Reduction by 1/10* *x
Table of Contents
I. Introduction and Background
A. Existing regulations
1. Surface Water Treatment Rule
2. Total Trlhalomethane MCL
3. Total Coliform Rule
4. Information Collection Rule
B. Public health concerns to be addressed
C. Statutory provisions
1. SDWA and 1986 provisions
2. Changes to initial provisions and new
mandates
D. Regulatory negotiation process
E. Information Collection Rule
F. Formation of 1997 Federal Advisory
Committee
G. Overview of 1994 proposed IESWTR
1. Summary of major elements
2. Alternative treatment requirements
3. Possible supplemental treatment
requirements
a. uncovered finished water reservoirs
b. cross connection control program
c. State notification of high turbidity levels
4. Other related issues
II. New Information and Key Issues To Be
Addressed
A. MCLG for Cryptosporidium
1. Summary of 1994 proposal and public
comments
2. New data and perspectives
3. Advisory Committee recommendations
and related issues
B. Removal of Cryptosporidium by filtration
1. Summary of 1994 proposal and public
comments
2. New data and perspectives
a. rapid granular filtration
b. other filtration technologies
c. multiple barrier approach
3. Advisory Committee recommendations
and related Issues
C. Turbidity control
1. Summary of 1994 proposal as It relates
to turbidity Issues and public comments
2. New data and perspectives
a. 95th percentile and maximum turbidity
levels of composite filtered water
b. individual filter performance
c. turbidity measurement
3. Advisory Committee recommendations
and related issues
D. Disinfection benchmark for Stage I DBF
MCLs
1. Applicability
2. Developing the profile and benchmark •
3. State review
4. Guidance
5. Request for public comment
E. Definition of ground water under direct
influence of surface water (GWUDI)—
inclusion of Cryptosporidium in the
definition
1. Summary of 1994 proposal and public
comments
2. Overview of existing guidance
3. Summary of new data and perspectives
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Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules
4. Request for public comment
F, Inclusion of Ctyptosporidium In watershed
control requirements
1. Summary of 1994 proposal and public
comments
2. Overview of existing guidance
3. Summary of new data and perspectives
G. Sanitary survey requirements
1. Summary of 1994 proposal
2. Overview of existing regulations and
guidance
3. New developments
4. Advisory Committee recommendations
and related issues
H. Covered finished water reservoirs
1. Summary of 1994 proposal and public
comments
2. Overview of existing information
3. Request for public comment
I. Cross connection control program
1. Summary of 1994 proposal and public
comments
2. Overview of existing information
3. Request for public comment
J. Recycling filter backwash water and
filtering to waste
1. Filter backwash recycle configuration
2. State drinking water regulations
3. Literature overview of standards of
practice
4. Filter-to-waste
5. Request for public comment
K. Certification criteria for water plant
operators
L. Regulatory compliance schedule and other
compliance-related issues
1. Regulatory compliance schedule
2. Compliance violations and State
primacy obligations
3. Compliance with current regulations
M. Disinfection studies
1. New Giardla inactivation studies at high
pH levels
2. Effectiveness of different disinfectants
on Ciyptosportdlum
3. New virus Inactivation studies
in. Economic Analysis of M-DBP Advisory
Committee Recommendations
A. Overview of RIA for proposed rule
B. What's changed since proposed rule
C. Summary of cost analysis
1. Total national costs
2. Household costs
D. Cost of turbidity performance criteria &
associated monitoring
1. System level impact analysis
2. National Impact analysis
a. decision tree
b. utility costs
c. State costs
E. Disinfection benchmark
1. Decision tree
2. Utility costs
3. State costs
F. Sanitary surveys
G. Summary of benefits analysis
IV. National Technology Transfer and
Advancement Act
I. Introduction and Background
A. Existing Regulations
1. Surface Water Treatment Rule
Under the Surface Water Treatment
Rule (SWTR)(54 FR 27486. June 29.
1989), USEPA set maximum
contaminant level goals of zero for
Giardla lamblia. viruses, and Legionella;
and promulgated national primary
drinking water regulations for all public
water systems (PWSs) using surface
water sources or ground water sources
under the direct influence of surface
water. The SWTR includes treatment
technique requirements for filtered and
unfiltered systems that are intended to
protect against the adverse health effects
of exposure to Giardia lamblia, viruses,
and Legionella, as well as many other
pathogenic organisms. Briefly, those
requirements include (1) removal or
inactivation of 3 logs (99.9%) for
Giardia and 4 logs (99.99%) for viruses;
(2) combined filter effluent performance
of 5 NTU as a maximum and 0.5 NTU
at 95th percentile monthly, based on 4-
hour monitoring for treatment plants
using conventional treatment or direct
filtration (with separate standards for
other filtration technologies); and (3)
watershed protection and other
requirements for unfiltered systems.
2. Total Trihalomethane MCL
USEPA set an interim Maximum
Contaminant Level (MCL) for total
trihalomethanes (TTHM) of 0.10 mg/1 as
an annual average in November 1979
(44 FR 68624). This standard was based
on the need to balance the requirement
for continued disinfection of water to
reduce exposure to pathogenic
•microorganisms while simultaneously
lowering exposure to disinfection
byproducts which might be
carcinogenic to humans.
The interim TTHM standard only
applies to any PWSs (surface water and/
or ground water) serving at least 10,000
people that add a disinfectant to the
drinking water during any part of the
treatment process. At their discretion,
States may extend coverage to smaller
PWSs. However, most States have not
exercised this option. About 80 percent
of the PWSs, serving populations of less
than 10,000, are served by ground water
that is generally low in THM precursor
content (USEPA, 1979) and which
would be expected to have low TTHM
levels even if they disinfect.
3. Total Coliform Rule
The Total Coliform Rule (54 FR
27544; June 29, 1989), revised in June
1989 and effective on December 31,
1990 applies to all public water systems
(USEPA, 1989b). This regulation sets
compliance with the Maximum
Contaminant Level (MCL) for total
coliforms as follows. For systems that
collect 40 or more samples per month,
no more than 5.0% of the samples may
be total coliform-positive; for those that
collect fewer than 40 samples, only one
sample may be total coliform-positive. If
a system exceeds the MCL for a month,
it must notify the public using
mandatory language developed by the
USEPA. The required monitoring
frequency for a system ranges from 480
samples per month for the largest
systems to once annually for certain of
the smallest systems. All systems must
have a written plan identifying where
samples are to be collected. In addition,
systems are required to conduct repeat
sampling after a positive sample.
The Total Coliform Rule also requires
each system that collects fewer than five
samples per month to have the system
inspected every 5 years (10 years for
certain types of systems using only
protected and disinfected ground
water.) This on-site inspection (referred
to as a sanitary survey) must be
performed by the State or by an agent
approved by the State.
4. Information Collection Rule
The Information Collection Rule (ICR)
is a monitoring and data reporting rule
that was promulgated on May 14, 1996
(61 FR 24354) (USEPA, 1996b). The
purpose of the ICR is to collect
occurrence and treatment information to
evaluate the need for possible changes
to the current Surface Water Treatment
Rule and existing microbial treatment
practices and to evaluate the need for
future regulation for disinfectants and
DBFs. The ICR will provide USEPA
with additional information on the ,
national occurrence in drinking water of
(1) chemical byproducts that form when
disinfectants used for microbial control
react with compounds already present
in source water and (2) disease-causing
microorganisms, including
Cryptosporidium, Giardia, and viruses.
The ICR will also collect engineering
data on how PWSs currently control
such contaminants. This information is
being collected because the regulatory
negotiation on disinfectants and DBFs
concluded that additional information
was needed to assess the potential
health problem created by the presence
of DBFs and pathogens in drinking
water and to assess the extent and
severity of risk in order to make sound
regulatory and public health decisions.
The ICR will also provide information to
support regulatory impact analyses for
various regulatory options, and to help
develop monitoring strategies for cost
effectively implementing regulations.
B. Public Health Concerns To Be
Addressed
In 1990, USEPA's Science Advisory
Board (SAB), an independent panel of
experts established by Congress, cited
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59489
drinking water contamination as one of
the most important environmental risks
and indicated that disease-causing
microbial contaminants (i.e., bacteria,
protozoa and viruses) are probably the
greatest remaining health risk
management challenge for drinking
water suppliers (USEPA/SAB 1990).
This view was prompted by the SAB's
concern about die number of waterborne
disease outbreaks in the U.S. Between
1980 and 1994, 379 waterborne disease
outbreaks were reported, with over
500,000 cases of disease. During diis
period, a number of agents were
implicated as the cause, including
protozoa, viruses and bacteria, as well
as several chemicals. Most of the cases
(but not-outbreaks) were associated with
surface water, and specifically with a
single outbreak of cryptosporidiosis in
Milwaukee (over 400,000 cases) (Craun,
Pers. Comm. 1997a).
The number of waterborne disease
outbreaks and cases is, however,
probably much greater than that
recorded because the vast majority of
waterborne disease is probably not
reported. Few States have an active
outbreak surveillance program and
disease outbreaks are often not
recognized in a community or, if
recognized, are not traced to the
drinking water source. This situation is
complicated by the fact that the vast
majority of people experiencing
gastrointestinal illness (predominantiy
diarrhea) do not seek medical attention.
For those who do, physicians generally
cannot attribute gastrointestinal illness
to any specific origin such as a drinking
water source. An unknown but probably
significant portion of waterborne
disease is endemic, i.e., not associated
with an outbreak, and thus is even more
difficult to recognize.
One of the key regulations USEPA has
developed and implemented to counter
pathogens in drinking water is the
SWTR. Among its provisions, the rule
requires that a public water system have
sufficient treatment to reduce the source
water concentration of Giardia and
viruses by at least 99.9% (3 logs) and
99.99% (4 logs), respectively.
The goal of the SWTR is to reduce risk
to less than one infection per year per
10,000 people (10-4). However, one of
the SWTR's shortcomings is that the
source waters of some systems have
high pathogen concentrations that,
when reduced by die levels required
under the rule, still may not meet a
common health goal (e.g., 10-4).
Another shortcoming of die SWTR is
that the rule does not specifically
control for the protozoan
Cryptosporidium. The first report of a
recognized outbreak caused by
Cryptosporidium was published during
the development of the SWTR
(D'Antonio et al., 1985). Other outbreaks
caused by this pathogen have since been
reported both in the United States and
other countries (Smidi et al.,1988; Hayes
et al., 1989; Levine and Craun, 1990;
Moore etal., 1993; Craun, 1993). A
particular public health challenge is that
simply increasing existing disinfection
levels above those most commonly
practiced in the United States today
does not appear to be an effective
strategy for controlling
Cryptosporidium.
In addition to these issues, tiiere is
another potentially counter-balancing
public health concern. The disinfectants
used to control microbial pathogens
may produce toxic or carcinogenic
disinfection byproducts (DBFs) when
they react with organic chemicals in the
source water. Thus, an important
question facing water supply
professionals is how to minimize the
risk from both microbial pathogens and
DBFs simultaneously.
At die time die SWTR was
promulgated, USEPA had limited data
concerning Giardia and
Cryptosporidium occurrence in source
waters and treatment efficiencies. The 3-
log removal/inactivation of Giardia
lamblia and 4-log removal/inactivation
of enteric viruses required by die SWTR
were developed to provide protection
from most pathogens in source waters.
However, additional data has become
available since promulgation of the
SWTR concerning source water
occurrence and treatment efficiencies
for Giardia, as well as for
Cryptosporidium (LeChevallier et al.
1991 a,b). A major concern is that if
systems currently provide four or more
logs of removal/inactivation for Giardia,
such systems might reduce existing
levels of disinfection to more easily
meet new DBF regulations, and thus
only marginally meet the three-log
removal/inactivation requirement for
Giardia lamblia specified in the current
SWTR. Depending upon source water
Giardia concentrations, such treatment
changes could lead to significant
increases in microbial risk (Regli et al.,
1993; Grubbs et al., 1992; USEPA,
1994b).
C. Statutory Provisions
1. SDWA and 1986 Provisions
The Safe Drinking Water Act (SDWA
or the Act), as amended in 1986,
requires USEPA to publish a "maximum
contaminant level goal" (MCLG) for
each contaminant which, in the
judgement of die USEPA Administrator,
"may have any adverse effect on the
health of persons and which are known
or anticipated to occur in public water
systems" (Section 1412(b)(3)(A)).
MCLGs are to be set at a level at which
"no known or anticipated adverse effect
on die health of persons occur and
which allows an adequate margin of
safety" (Section 1412(b)(4)).
The Act also requires diat at the same
time USEPA publishes an MCLG, which
is a non-enforceable healtii goal, it also
must publish a National Primary
Drinking Water Regulation (NPDWR)
that specifies either a maximum
contaminant level (MCL) or treatment
technique (Sections 1401(1) and
1412(a)(3)). USEPA is audiorized to
promulgate a NPDWR "that requires the
use of a treatment technique in lieu of
establishing a MCL," if die Agency finds
tiiat "it is not economically or
technologically feasible to ascertain die
level of die contaminant".
Section 1414 (c) of die Act requires
each owner or operator of a public water
system to give notice to the persons
served by die system of any failure to
comply with an MCL or treatment
technique requirement of, or testing
procedure prescribed by, a NPDWR and
any failure to perform monitoring
required by section 1445 of die Act.
Section 1412(b)(7)(C) of die SDWA
requires die USEPA Administrator to
publish a NPDWR "specifying criteria
under which filtration (including
coagulation and sedimentation, as
appropriate) is required as a treatment
technique for public water systems
supplied by surface water sources". In
establishing these criteria, USEPA is
required to consider "the quality of
source waters, protection afforded by
watershed management, treatment
practices (such as disinfection and
lengdi of water storage) and other
factors relevant to protection of health".
This section of the Act also requires
USEPA to promulgate a NPDWR
requiring disinfection as a treatment
technique for all public water systems
and a rule specifying criteria by which
variances to this requirement may be
granted.
2. Changes to Initial Provisions and New
Mandates
In 1996, Congress reauthorized the
Safe Drinking Water Act. Several of the
1986 provisions discussed above were
renumbered and augmented witii
additional language, while odier
sections mandate new drinking water
requirements. These modifications, as
well as new provisions, are detailed
below.
, As part of the 1996 amendments to
die Safe Drinking Water Act (die
Amendments), USEPA's general
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authority to set a MCLG and NPDWR
was modified to apply to contaminants
that may "have an adverse effect on the
health of persons", that are "known to
occur or there is a substantial likelihood
that the contaminant will occur in
public water systems with a frequency
and at levels of public health concern",
and for which "in the sole judgement of
the Administrator, regulation of such
contaminant presents a meaningful
opportunity for health risk reduction for
persons served by public water systems'
(1986 SDWA Section 1412 (b)(3)(A)
stricken and amended with
14l2(b)(D(A)).
The Amendments also require that
USEPA. when proposing a NPDWR that
includes an MCL or treatment
technique, publish and seek public
comment on health risk reduction and
cost analyses. The Amendments also
require USEPA to take into
consideration the effects of
contaminants upon sensitive
subpopulations (i.e. infants, children,
pregnant women, the elderly, and
Individuals with a history of serious
illness), and other relevant factors.
(Section 1412 (b)(3)(C)).
The 1996 Amendments also newly
require USEPA to promulgate an Interim
Enhanced SWTR and a Stage I
Disinfectants and Disinfection
Byproducts Rule by November 1998. In
addition, the 1996 Amendments require
USEPA to promulgate a Final Enhanced
SWTR and a Stage 2 Disinfection
Byproducts Rule by November 2000 and
May 2002, respectively (Section
Under the Amendments of 1996,
recordkeeping requirements were
modified to apply to "every person who
is subject to a requirement of this tide
or who is a grantee" (Section 1445
(a)(l)(A)). Such persons are required to
"establish and maintain such records,
make such reports, conduct such
monitoring, and provide such
information as die Administrator may
reasonably require by regulation . . .".
D. Regulatory Negotiation Process
In 1992 USEPA initiated a negotiated
rulemaking to develop a disinfectants/
disinfection byproducts rule. The
negotiators Included representatives of
State and local health and regulatory
agencies, public water systems, elected
officials, consumer groups and
environmental groups. The Committee
met from November 1992 through June
1993.
Early in the process, the negotiators
agreed that large amounts of information
necessary to understand how to
optimize the use of disinfectants to
concurrently minimize microbial and
DBF risk on a plant-specific basis were
unavailable. Nevertheless, the
Committee agreed that USEPA propose
a disinfectants/disinfection byproducts
rule to extend coverage to all
community and nontransient
noncommunity water systems that use
disinfectants. This rule proposed to
reduce die current TTHM MCL, regulate
additional disinfection byproducts, set
limits for the use of disinfectants, and
reduce the level of organic compounds
in the source water that may react with
disinfectants to form byproducts.
One of the major goals addressed by
the Committee was to develop an
approach that would reduce the level of
exposure from disinfectants and DBFs
without undermining the control of
microbial pathogens. The intention was
to ensure that drinking water is
microbiologically safe at the limits set
for disinfectants and DBFs and that
these chemicals do not pose an
unacceptable risk at these limits.
Following months of intensive
discussions and technical analysis, the
Committee recommended the
development of three sets of rules: a
two-staged Disinfectants/Disinfection
Byproduct Rule (proposal: 59 FR 38668,
July 29,1994) (USEPA, 1994a), an
"interim" ESWTR (proposal: 59 FR
38832, July 29,1994) (USEPA, 1994b),
and an Information Collection rule
(proposal: 59 FR 6332, February 10,
1994) (USEPA, 1994c). The IESWTR
would only apply to systems serving
10,000 people or more. The Committee
agreed that a "long-term" ESWTR
(LTESWTR) would be needed for
systems serving fewer than 10,000
people when the results of more
research and water quality monitoring
became available. The LTESWTR could
also include additional refinements for
larger systems.
The approach in developing these
proposals considered the .constraints of
simultaneously treating water to control
for both microbial contaminants and
DBFs. As part of this effort, the
Negotiating Committee concluded that
the SWTR may need to be revised to
address health risk from high densities
of pathogens in poorer quality source
waters and from the protozoan,
Cryptosporidium. The Committee also
agreed that the schedules for IESWTR
and LTESWTR should be "linked" to
the schedule for the Stage 1 DBF Rule
to assure simultaneous compliance and
a balanced risk-risk based
implementation. The Committee agreed
that additional information on health
risk, occurrence, treatment technologies,
and analytical methods needed to be
developed in order to better understand
the risk-risk tradeoff, and how to
accomplish an overall reduction in risk.
Finally the Negotiating Committee
agreed that to develop a reasonable set
of rules and to understand more fully
die limitations of the current SWTR,
additional field data were critical. Thus,
a key component of the regulation
negotiation agreement was the
promulgation of the Information
Collection Rule (ICR) noted above and
described in more detail below.
E. Information Collection Rule
As stated above, the ICR established
monitoring and data reporting
requirements for large public water
systems serving populations over
100,000. About 350 PWSs operating 500
treatment plants are involved in the data
collection effort. Under the ICR, these
PWSs monitor their source water for
bacteria, viruses, and protozoa (surface
water sources only); water quality
factors affecting DBF formation; and
DBFs within the treatment plant and in
the distribution system. In addition,
PWSs must provide operating data and
a description of their treatment plan
design. Finally, a subset of PWSs
perform treatment studies, using either
granular activated carbon or membrane
processes, to evaluate DBF precursor
removal. Monitoring for treatment study
applicability began in September 1996.
The remaining occurrence monitoring
began in July 1997.
The initial intent of the ICR was to
collect monitoring data and other
information for use in developing the
Stage 2 DBPR and IESWTR and to
estimate national costs for various
treatment options. However, because of
delays in promulgating the ICR and
technical difficulties associated with
laboratory approval and review of
facility sampling plans, most ICR
monitoring did not begin until July 1,
1997. As a result of this delay and the
new Stage 1 DBPR and IESWTR
deadlines specified in the 1996 SDWA
amendments, ICR data will not be
available for analysis in connection with
these rules. In place of the ICR data, the
Agency has worked with stakeholders to
identify additional data developed since
1994 that can be used in components of
these rules. USEPA intends to continue
to work with stakeholders in analyzing
and using the comprehensive ICR data
and research for developing subsequent
revisions to die SWTR and the Stage 2
DBF Rule.
F. Formation of 1997 Federal Advisory
Committee
In May 1996, the Agency initiated a
series of public informational meetings
to exchange information on issues
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Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules 59491
related to microbial and disinfectants/
disinfection byproducts regulations. To
help meet the deadlines for the IESWTR
and Stage 1 DBPR established by
Congress in the 1996 SDWA
Amendments and to maximize
stakeholder participation, the Agency
established the Microbial and
Disinfectants/Disinfection Byproducts
(M-DBP) Advisory Committee under the
Federal Advisory Committee Act
(FACA) on February 12, 1997, to collect,
share, and analyze new information and
data, as well as to build consensus on
the regulatory implications of this new
information. The Committee consists of
17 members representing USEPA, State
and local public health and regulatory
agencies, local elected officials, drinking
water suppliers, chemical and
equipment manufacturers, and public
interest groups.
The Committee met five times, in
March through July 1997, to discuss
issues related to the IESWTR and Stage
1 DBPR. Technical support for these
discussions was provided by a
Technical Work Group (TWG)
established by the Committee at its first
meeting in March 1997. The
Committee's activities resulted in the
collection, development, evaluation,
and presentation of substantial new data
and information related to key elements
of both proposed rules. The Committee
reached agreement on the following
major issues discussed in this Notice
and the Notice for the Stage 1 DBPR
published elsewhere in today's Federal
Register: (1) MCLs for TTHMs, HAAS
and bromate; (2) requirements for
enhanced coagulation and enhanced
softening (as part of DBF control); (3)
microbial benchmarking/profiling to
provide a methodology and process by
which a PWS and the State, working
together, assure that there will be no
significant reduction in microbial
protection as the result of modifying
disinfection practices in order to meet
MCLs for TTHM and HAAS; (4)
disinfection credit; (5) turbidity; (6)
Cryptosporidium MCLG; (7) removal of
Cryptosporidium; (8) role of
Cryptosporidium inactivation as part of
a multiple barrier concept and (9)
sanitary surveys. The Committee's
recommendations to USEPA on these
issues were set forth in an Agreement In
Principle document dated July 15, 1997.
This document is included with this
notice as Appendix 1.
G. Overview of IESWTR 1994 Proposal
1. Summary of Major Elements
As part of the IESWTR July 29, 1994,
Federal Register notice (59 FR 38832),
USEPA proposed to revise the SWTR to
provide additional protection against
pathogens in drinking water. USEPA
proposed to set the MCLG for
Cryptosporidium at zero based on
animal studies and human
epidemiology studies of waterborne
outbreaks of cryptosporidiosis. The
proposal also focused on treatment
requirements for the waterborne
pathogens Giardia lamblia,
Cryptosporidium, Legionella and
viruses that would apply to all public
water systems that use surface water or
ground water under the influence of
surface water and serve 10,000 people
or more. Major features of the proposal
included a stricter watershed control
requirement for systems using surface
water that wish to avoid filtration; a
change in the definition of ground water
under the influence of surface water to
include the presence of
Cryptosporidium; a periodic sanitary
survey requirement for all systems using
surface water or ground water under the
influence of surface water; and several
alternative requirements, described
below, for augmenting treatment control
of Giardia lamblia, Cryptosporidium,
and viruses. USEPA also requested
comment on several supplemental
provisions and on other related issues,
described below.
2. Alternative Treatment Requirements
USEPA proposed five treatment
alternatives for controlling Giardia
lamblia, Cryptosporidium, and viruses.
Each alternative included several
options. Alternative A addressed
enhanced treatment for Giardia lamblia
only. Alternatives B and C addressed
treatment for Cryptosporidium only.
Alternative D addressed enhanced
treatment for viruses only. Alternative E
would maintain existing levels of
treatment for Giardia lamblia and
viruses.
a. Alternative A. Enhanced treatment
for Giardia lamblia. The SWTR
currently requires a 99.9 percent (3-log)
removal/inactivation of Giardia lamblia
for all surface waters, regardless of
Giardia lamblia cyst concentrations in
the source water. Under Alternative A,
the minimum level of treatment a
system would be required to provide
(e.g., 3, 4, 5 or 6 log removal/
inactivation) would depend on the
Giardia lamblia density in the source
water as determined by monitoring over
some specified interval of time. The
level of prescribed treatment for a
particular system would correspond to
providing water below an annual risk
level for Giardia lamblia infections (e.g.
10-").
b. Alternative B. Specific Treatment
for Cryptosporidium. USEPA also
proposed a treatment technique for
Cryptosporidium similar to the proposal
for Giardia under Alternative A, such
that the required level of
Cryptosporidium treatment for any
particular system would depend on the
density of Cryptosporidium in the
source water.
c. Alternative C. 99% (2-log) removal
of Cryptosporidium. Under this
alternative, USEPA would require
systems to achieve at least a 99% (2-log)
removal of Cryptosporidium by
filtration (with pretreatment). The 2-log
level was based on the premise that a 3-
log level (as currently required for
Giardia removal/inactivation) is not
economically or technologically
possible, since data suggests that
Cryptosporidium is consistently more
resistant to disinfection than is Giardia.
USEPA indicated that it would continue
to assess new field and laboratory data
to control Cryptosporidium by physical
removal and disinfection for
consideration in subsequent microbial
regulations.
d. Alternative D. Specific disinfection
treatment for viruses. The SWTR
required systems to achieve a four-log
removal/inactivation of viruses. This is
to be achieved through a combination of
filtration and disinfection or, for
systems not required to filter their
source waters, by disinfection alone.
However, this level of treatment may
not be adequate to achieve a particular
health risk (e.g., 10~4 infections/yr/
person) for viruses. Viruses are of
particular concern, given that one or
several virus particles may be infectious
(Regli et al., 1991) and that several
enteric viruses are associated with
relatively high mortality rates (Bennett
et al., 1987). Failure or impairment of
filtration performance could allow
substantial pathogen contamination of
drinking water, particularly if the
disinfection barrier following filtration
is minimal.
Alternative D would require that
systems provide sufficient disinfection
such that disinfection alone would
achieve at least a 0.5-log inactivation of
Giardia lamblia or, alternatively, a 4-log
inactivation of viruses. This proposed
approach would be independent of the
level of physical removal or the source
water density of viruses. If the filtration
process was able to remove three logs of
Giardia lamblia, a system would still
have to provide at least an additional
0.5-log inactivation of Giardia lamblia
or 4-log inactivation of viruses by
disinfection.
e. Alternative E. No change to existing
SWTR treatment requirements for
Giardia lamblia and viruses. Alternative
E maintains existing SWTR levels of
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59492
Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules
treatment for Giardia lamblia and
viruses. USEPA could regulate
Cryptosporidium directly (e.g.,
Alternative C above) or make a finding
that existing SWTR filtration and
disinfection requirements are adequate
to control this organism.
3, Possible Supplemental Treatment
Requirements
USEPA also requested comment on
three supplemental requirements
regarding uncovered finished water
reservoirs, cross connection control and
State notification of turbidity levels.
a. Uncovered Finished Water
Reservoirs. As part of the 1994 proposal,
USEPA requested comment on possible
supplemental requirements for
uncovered finished water reservoirs.
The Agency noted that USEPA
guidelines recommend that all finished
water reservoirs be covered (USEPA,
199 la) and that the American Water
Works Association (AWWA) also has
issued a policy statement that strongly
supports the covering of such reservoirs
(AWWA. 1993).
b. Cross Connection Control Program.
USEPA requested comment on whether
to require States or public water systems
to have cross connection control
programs. Plumbing cross-connections
are actual or potential connections
between a potable and non-potable
water supply (USEPA. 1989a).
According to Craun (1991), 24% of the
waterborne disease outbreaks that
occurred during 1981-1990 were caused
by water contamination in the
distribution system, primarily as the
result of cross-connections and main
repairs.
c. State Notification of High Turbidity
Levels. USEPA also requested comment
on whether to require systems to notify
the State as soon as possible for
persistent turbidity levels above the
performance standards or for any other
situation that is not now a violation of
the turbidity standards. Under die
SWTR. any time the turbidity of a
treatment plant's combined filter
effluent exceeds 5 NTU the system must
notify the State as soon as possible, but
no later than the end of the next
business day. In addition, the system
must notify the public as soon as
possible, but in no case later than 14
days after the violation.
USEPA indicated in the proposal that
it was considering broadening the
requirement for State notification. The
Agency suggested it might, for example,
require systems to notify the State as
soon as possible if at any point during
the month it becomes apparent diat a
system will violate the monthly 95th
percentile turbidity performance
standard specified in the SWTR, rather
dian wait to the end of the month.
USEPA oudined a number of public
healdi reasons for requiring swift State
notification for persistent turbidity
levels. Pathogens may accompany the
turbidity particles that exit the filters,
especially with poor quality source
waters. High turbidity levels in the
filtered water, even for a limited time,
may represent a significant risk to the
public. USEPA's proposed approach
was intended to allow States to respond
in controlling a potentially serious
problem more quickly.
4. Other related issues. The Agency
also requested comments on other
issues related to possible IESWTR
options. A number of these are listed
below.
(a) To what extent should the ESWTR
address the issue of recycling filter
backwash, given its potential for
increasing the densities of Giardia
lamblia and Cryptosporidium on the
filter?
(b) Should the ESWTR define
minimum certification criteria for
surface water treatment plant operators?
Currently the SWTR (40 CFR 141.70)
requires such systems to be operated by
"qualified personnel who meet the
requirements specified by the State."
(c) What criteria, if any, should the
ESWTR include to ensure that systems
optimize treatment plant performance?
(d) Should turbidity performance
criteria be modified? Should criteria
pertain to individual filters?
(e) Should the rule include a
performance standard for particle
removal?
(f) Should the rule include a
requirement for an early warning for
high turbidity?
(g) Under what conditions could
systems be allowed different log
removal credits dian is currently
recommended in die SWTR Guidance
Manual?
(h) How should USEPA decide, in
developing a Notice of Data Availability,
what treatment approach(es) is most
suitable for additional public comment?
II. New Information and Key Issues to
be Addressed
A. MCLG for Cryptosporidium
1. Summary of 1994 Proposal and
Public Comments
The July 29,1994, Federal Register
notice proposed to set the MCLG for
Cryptosporidium at zero. The purpose
of the MCLG is to protect public healtii.
The reasons for this determination were
based upon animal studies and human
epidemiology studies of waterborne
outbreaks of cryptosporidiosis.
Most cpmmenters supported an
MCLG of zero for Cryptosporidium.
Those who provided reasons stated that
(1) a single cell could infect, and data
do not support a threshold dose below
which an outbreak or disease will not
occur, (2) die organism is present in
water and has caused major waterborne
disease outbreaks, and (3) it is
consistent witii die goals set under die
SWTR and Total Coliform Rule.
Commenters who opposed the proposed
MCLG stated dial USEPA needed more
health risk and organism/disease
transmission data and better analytical
methods before setting an MCLG and
regulating Cryptosporidium.
2. New data and Perspectives
Since publication of the proposed
rule, results of a human feeding study
have become available. Dupont et al.
(1995) fed 29 healthy volunteers single
doses ranging from 30 to 1 million C.
parvum oocysts obtained from a calf. Of
die 16 volunteers who received 300 or
more oocysts, 88% became infected. Of
the five volunteers who received the
lowest dose (30 oocysts), one became
infected. The median infective dose was
132 oocysts. According to a
mathematical model based upon the
Dupont et al. data, 0.5% of a population
exposed to an average dose of one
oocyst, would be expected to become
infected. (Haasetal., 1996).
An important concern is that certain
populations are at greater risk of
waterborne disease infection than
others. These vulnerable populations
include die immunocompromised;
children, especially die very young; die
elderly; and pregnant women (Gerba et
al. 1996; Payer and Ungar 1986). The
most significant segment within these
vulnerable populations with regard to
cryptosporidiosis is people who are
immunocompromised. In patients with
severely weakened immune systems,
(e.g cancer, AIDS patients),
cryptosporidiosis can be serious, long-
lasting and sometimes fatal. There is
concern about cryptosporidiosis in
immunocompromised individuals
because currently there is no cure for
die disease.
C. parvum is the only
Cryptosporidium species known for
certain to infect humans. One
controversial report (the only one of its
kind) found evidence that C. baileyi,
which infects birds, was present in the
stools and other autopsied organs of an
immunodeficient patient (Ditrich et al.,
1991). There was no indication that
Cryptosporidium had been responsible
in this instance for any adverse health
effects. C. parvum also infects many
other mammals. While C. parvum is a
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59493
well-documented human pathogen,
strain variation may occur and one
strain may cause infection and/or
disease at a higher or lower
concentration than other strains. USEPA
is currendy funding research
[Cryptosporidium virulence study using
different strains, Herbert Dupont] to
examine this issue.
There is some question about the
taxonomy (i.e., classification) of species
within the genus Cryptosporidium. Up
until 1980, classification was based on
the assumption that a particular species
only infected one type of animal. This
assumption appears to be incorrect;
hence other appropriate taxonomy
schemes'have been suggested.
An important issue not directly
related to the MCLG involves the
measurement of C. parvum in water.
With current technology, it is often very
difficult to distinguish between viable
and non-viable oocysts. When
Cryptosporidium is identified it is often
not clear whether it is C. parvum or
another species. Several
Cryptosporidium species look similar to
C. parvum and react to "specific" C.
parvum stains in a like manner (cross-
reactions). In addition, it can be difficult
to distinguish Cryptosporidium from
alga and invertebrate eggs (Clancy et al.
1994)
3. Advisory Committee
Recommendations and Related Issues
The M-DBP Federal Advisory
Committee supported the proposed
establishment of a Cryptosporidium
MCLG at zero. However, a key issue
identified by the Committee and public
commenters is whether the MCLG
should be set at the genus level (i.e.,
Cryptosporidium), as proposed, or at the
more specific species level (i.e., C.
parvum). Setting the MCLG at the genus
level would automatically include any
Cryptosporidium species other than C.
parvum that is later found to be
pathogenic to humans. In contrast,
setting an MCLG at the species level
would indicate that only C. parvum
infects humans, and would also be
consistent with the approach taken
under the SWTR for Giardia where the
MCLG is set at the species level (i.e., G.
lamblia). USEPA has not decided which
approach is most appropriate and seeks
public comment on this issue.
As indicated above, USEPA's intent in
establishing this MCLG at zero is to
protect public health. The Agency
believes there is adequate research data
to support this determination. However,
as noted above, the Agency recognizes
that there is scientific uncertainty on the
issue of Cryptosporidium taxonomy and
on the question of cross reactions
between species. USEPA expects further
clarification on this issue as research
continues, Cryptosporidium analytical
methods improve, and more is learned
about the circumstances under which
cross-reactivity between species occurs.
The Agency also wishes to emphasize
that the scope or specificity of the
MCLG may be modified in the future to
reflect new research and additional
information about particular species
that represent a significant risk to
human health.
As part of tills notice, USEPA requests
comment on whether to establish a
Cryptosporidium MCLG at the genus
level as proposed or at the species level
(i.e., Cryptosporidium vs.
Cryptosporidium parvum). USEPA also
requests copies of any additional
research, data or other information
related to this issue.
B. Removal of Cryptosporidium by
Filtration
1. Summary of 1994 Proposal and
Public Comments Received
One of USEPA's proposed treatment
Alternatives (Alternative C) would
require filtered systems to achieve at
least a 2 log removal of Cryptosporidium
oocysts. USEPA recognized that the
proposed removal level was based on
limited data and therefore solicited
comment on whether other minimum
removal levels might be appropriate.
Most commenters addressing the
issue of treatment alternatives
supported Alternative C. Some
commenters opposed any treatment
requirement greater than a 2 log removal
due to a lack of better understanding of
dose-response, effectiveness of
treatment, and analyses to justify the
higher treatment costs involved.
Other commenters referred to specific
studies (Nieminski 1995; Patania et al.,
1995) that provided additional
information on Cryptosporidium
removal. One commenter cited a study
(Parker and Smith, 1993), where oocyst
damage was observed after agitation
with sand. This study postulated that
oocysts may be damaged as they pass
through the filtration media. This
commenter also pointed to the lack of
data on cyst removal by full-scale plants
and recommended that additional
research be conducted. Some
commenters recognized the need to
regulate Cryptosporidium, but opposed
having the level of treatment based
upon source water pathogen density
(alternative B). One commenter
indicated that further implementation
and evaluation of the adequacy of the
SWTR needs to occur before modifying
it.
2. New Data and Perspectives
a. Rapid Granular Filtration. Table 1
summarizes research pertinent to
Cryptosporidium and Giardia lamblia
removal efficiencies by rapid granular
filtration. Brief descriptions of these
studies and a summary of'key points
follow.
TABLE 1 .—CRYPTOSPORIDIUM AND GIARDIA LAMBLIA REMOVAL EFFICIENCIES BY RAPID GRANULAR FILTRATION
Type of treatment plant
Conventional filtration plants
Do
Do
Do
Do
Do
Do
Do
Do
Do
Do
Do ...
DoCrypt 1 5-2
Direct filtration plants
Do
Log removal
Crypt 2.7-5.9
Giardia 3 4—5 8
Crypt 2.3-3.0
Giardia 3.3—3.4
Crypt 2.7-3.1
Giardia 31—35
Crypt 2-2.5
Giardia 2—2 5
Crypt 2 3-2.5
Giardia 2 2—2 8
Crypt 2-3
Giardia and ....
operation considered ot optimized)
Crypt 1 5-4 0
Giardia 1.5-4.8
Experimental design
Pilot Plants
do
Pilot scale plant
+full scale plant with seeded cysts/
oocysts.
Pilot Plants
do
Full scale plants
Full scale plants
Full scale plants
do
Pilot scale plant
Full scale plant
Pilot Plants
do
Researcher
Patania et al. 95.
Do.
Nieminski/Ongerth 95.
Do.
Ongerth/Pecaroro 95.
Do.
LeChevallier et al. 91 b.
LeChevallier et al. 91 b.
LeChevallier/Norton 92.
Do.
Foundation for Water.
Research 94.
Kelley et al. 95.
Patania et al 1 995.
Do.
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Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules
TABLE 1.—CRYPTOSPORIDIUM AND GIARDIA LAMBLIA REMOVAL EFFICIENCIES BY RAPID GRANULAR FILTRATION—
Continued
Type of treatment plant
rv>
n«
Do
Log removal
Crypt 2 8-3 0
Giardla 3 3-3 9
Crypt 2-3
Experimental design
do
do
do
Researcher
Nieminski/Ongerth 95.
Do.
Westetal. 1994.
Patania, Nancy L; etal. 1995
Raw water turbidities were between
0.2 and 13. When treatment conditions
were optimized for turbidity and
particle removal at four different sites,
Cryptosporidium removal ranged from
2.7 to 5.9 log and Giardla removal
ranged from 3.4 to 5.1 log during stable
filter operation. The median turbidity
removal was 1.4 log. whereas the
median particle removal was 2 log.
Median oocyst and cyst removal was 4.2
log. A filter effluent turbidity of 0.1
NTU or less resulted in the most
effective cyst removal, by up to 1 log
greater than when filter effluent
turbidities were greater than 0.1 NTU
(within the 0.1 to 0.3 NTU range) (see
Figures 1 and 2 below).
Cryptosporidium removal rates of less
than 2.0 log (indicated in Figures 1 and
2) occurred at the end of the filtration
cycle.
Blackened data points in these figures
represent data in which oocysts were
not detected in the filtered water. The
log removal values shown would be
greater than indicated had the influent
oocyst concentration been sufficiently
high to show oocyst detection in the
filtered water. The researchers also
noted that removal of Cryptosporidium
was 0.4 to 0.9 log lower during filter
ripening than during stable filter
operation; Giardia removal was
generally 0.4 to 0.5 log lower during
ripening. Cryptosporidium removal was
1.4 to 1.8 log higher for conventional
treatment (including sedimentation) as
compared to direct filtration. Similarly,
Giardia removal was 0.2 to 1.8 log
higher. Figures 1 and 2 below show the
log removal rates discussed above.
BILLING CODE 6560-SO-P
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59495
1
00
3
7.o:
6.0-:
5.0--
4.0:
3.0-
2.0-
1.0"
0.01
.(
C. parvum
o
0M * ° 0
jff*** D
jFa^ff2cP°m
^>* -
^
c ° °°" o Turbidity S 0.1 NTU
• Turbidity S 0.1 NTU
0 c (C. parvum removal > indicated value)
a Turbidity * 0.1 NTU
• Turbidity > 0.1 NTU
(C. narvum removal > indicated value)
i i iiiiiiiii i i
31 .1 15 10 20 30 50 70 80 90 95 99 99.9 99
Percent of Samples Less Than or Equal to a Given Value
99
Figure 1: Cumulative probability distribution of aggregate pilot plant data for C. parvum
removal when filtered water turbidity was < 0.1 NTU and > 0.1 NTU (extracted from Patania
et al. 1995). Reprinted from Optimization of Filtration for Cyst Removal, by permission.
Copyright ©1995, American Water Works Association and AWWA Research Foundation.
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59496 Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules
7.0
6.0-j
5.0'
4.0'
2.0:
i.o-
0.0
G. murii
o Turbidity 5 0.1 NTU
* Turbidity <; 0.1 NTU
(G. muris removal > indicated value)
o Turbidity > 0.1 NTU
• Turbidity > 0.1 NTU
(G. mum removal > indicated value)
.01 .1 1 5 10 20 30 50 70 80 90 95 99 99.9 99.99
Percent of Samples Less Than or Equal to a Given Value
Figure 2: Cumulative probability distribution of aggregate pilot plant data for G. muris
removal when filtered water turbidity was < 0.1 NTU and > 0.1 NTU (extracted from Patania
et al. 1995). Reprinted from Optimization of Filtration for Cyst Removal, by permission.
Copyright ©1995, American Water Works Association and AWWA Research Foundation.
B1UJNO CODE KtO-SO-C
Nieminskl, Eva C. and Ongerth, Jerry E.
1995
This study evaluated performance in
a pilot plant and in a full scale plant
(not in operation during the time of the
study) and considered two treatment
modes: direct filtration and
conventional treatment. The source
water of the full scale plant had
turbidities typically between 2.5 and 11
NTU with a peak level of 28 NTU. The
source water of the pilot plant typically
had turbidities of 4 NTU with a
maximum of 23 NTU. For the pilot
plant, achieving filtered water
turbidities between 0.1-0.2 NTU,
Cryptosporidium removals averaged 3.0
log for conventional treatment and 3.0
log for direct filtration, while the
respective Giardia removals averaged
3.4 log and 3.3 log. For the full scale
plant, achieving similar filtered water
turbidities, Ctyptosportdium removal
averaged 2.25 log for conventional
treatment and 2.8 log for direct
filtration, while the respective Giardia
removals averaged 3.3 log for
conventional treatment and 3.9 log for
direct filtration. Differences in
performance between direct filtration
and conventional treatment by the full
scale plant were attributed to different
source water quality during the filter
runs.
Ongerth, Jerry E. and Pecoraro, J.P. 1995
This project used very low turbidity
source waters (0.35 to 0.58 NTU). With
optimal coagulation, 3 log removal for
both cysts were obtained. In one test
run, where coagulation was
intentionally suboptimal, the removals
were only 1.5 log for Cryptosporidium
and 1.3 log for Giardia. This
emphasized the importance of proper
coagulation for cyst removal even
though the effluent turbidity was less
than 0.5 NTU.
LeChevallier, Mark W. and Norton,
William D. 1992
Source water turbidities ranged from
less than 1 to 120 NTU. Removals of
Giardia and Cryptosporidium (2.2-2.8
log) were slightly less than those
reported by other researchers, possibly
because full scale plants were studied,
under less ideal conditions than the
pilot plants. The participating treatment
plants were in varying stages of
treatment optimization. Removal
achieved a median of 2.5 log for
Cryptosporidium and Giardia.
LeChevallier, Mark W.; Norton, William
D.; and Lee, Raymond G. 1991b
This study evaluated removal
efficiencies for Giardia and
Cryptosporidium in 66 surface water
treatment plants in 14 States and 1
Canadian province. Most of the utilities
achieved between 2 and 2.5 log
removals for both Giardia and
Cryptosporidium. When no cysts were
detected on the finished water below
detection protozoan levels were set at
the detection limit for calculating
removal efficiencies.
Foundation for Water Research 1994
Raw water turbidity ranged from 1 to
30 NTU. Cryptosporidium oocyst
removal was between 2 and 3 log.
Investigators concluded that any
measure which reduced filter effluent
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59497
turbidity should reduce risk from
Cryptosporidium. The importance in
selecting coagulants, dosages, and pH
should not be overlooked. Apart from
turbidity, indicators of possible reduced
efficiency for oocyst removal would be
increased color and dissolved metal ion
coagulant concentration in the effluent,
for these are indications of reduced
efficiency of coagulation/ flocculation.
Kelley, M.B. et al. 1995
Protozoa removal was between 1.5
and 2 log. The authors speculated that
this low Cryptosporidium removal
occurred because the coagulation
process was not optimized, though the
finished water turbidity was less than
0.5 NTU. Also, when cysts were not
detected in the finished water below
detection values were assumed as
filtered water concentration levels.
West, Thomas; etal. 1994
Pilot scale direct filtration was used
with anthracite mono-media at filtration
rates of 6 and 14 gpm/sq ft. Raw water
turbidity was 0.3 to 0.7 NTU. Removal
efficiencies for Cryptosporidium at both
filtration rates were 2 log during filter
ripening (despite turbidity exceeding
0.2 NTU), and 2 to 3 log for the stable
filter run, declining significantly during
particle breakthrough. When effluent
turbidity was less than 0.1 NTU,
removal typically exceeded 2 log. Log
removal of Cryptosporidium generally
exceeded that for particle removal.
Summary of Studies
The studies described above indicate
that rapid granular filtration, when
operated under appropriate coagulation
conditions and optimized to achieve a
filtered water turbidity level of less than
0.3 NTU, should achieve at least 2 log
of Cryptosporidium removal. Removal
rates vary widely, up to almost 6 log,
depending upon water matrix
conditions, filtered water turbidity
effluent levels, and where and when
removal efficiencies are measured
within the filtration cycle. The highest
log pathogen removal rates occurred in
those pilot plants and systems which
achieved very low finished water
turbidities (less than 0.1 NTU).
Members of the M-DBP Advisory
Committee discussed that tighter
turbidity performance criteria would
increase the likelihood of systems
achieving higher oocyst removal rates.
As a general principle, members of the
M-DBP Advisory Committee indicated
that if a utility were required to achieve
less than 0.3 NTU 95% of the time, it
would target substantially lower
turbidity levels in order to have
confidence that it will not exceed the
0.3 level. This principle was also
recognized by the M-DBP Advisory
Committee's Technical Work Group and
served as a technical basis for much of
the Committee's discussion of turbidity
(i.e., that if the performance standard is
0.3 NTU systems would target achieving
less than 0.2 NTU 95 percent of the
time).
The Patania and Nieminski/Ongerth
studies as they relate to finished water
turbidity levels and log removal are
particularly relevant to this point. These
particular studies involve finished water
turbidity at low levels in the same range
as the finished water target identified by
the Committee. The associated removal
of Cryptosporidium at these turbidity
levels was reliably in the range of 2 log
or greater.
Other key points discussed during the
Advisory Committee's deliberations
related to the studies include:
• As turbidity performance improves
for treatment of a particular water, there
tends to be greater removal of
Cryptosporidium.
• Pilot plant study data in particular
indicate high likelihood of achieving at
least 2 log removal when plant
operation is optimized to achieve low
turbidity levels. Moreover, pilot studies
represented in the table tend to be for
low-turbidity waters, which are
considered to be the most difficult to
treat regarding paniculate removal and
associated protozoan removal. Since
high removal rates have been
demonstrated in pilot studies using
lower-turbidity source waters, it is
likely that similar or higher removal
rates would be achieved for higher-
turbidity source waters.
• The evaluation of Cryptosporidium
removal in full-scale plants can be
difficult in that this data includes many
non-detects in the finished water. In
these cases, values assigned at the
detection limit will likely result in over-
estimation of oocysts in the finished
water. This in turn means that removal
levels will tend to be under-estimated.
• Another factor that contributes to
differences among the data is that some
of the full-scale plant data comes from
plants that are not optimized, but that
still meet existing SWTR requirements.
In such cases, oocyst removal may be
less than 2 log. In those studies that
indicate that full-scale plants are
achieving greater than 2 log removal
(LeChevallier studies in particular), die
follow.ing characteristics pertain:
—Substantial numbers of filtered water
measurements resulted in oocyst
detections;
—Source water turbidity tended to be
relatively high compared to some of
the other studies;
—A significant percentage of these
systems were also achieving low
filtered water turbidities, substantially
less tfian 0.5 NTU.
• Removal of Cryptosporidium can
vary significantly in the course of the
filtration cycle (i.e., at the start-up and
end of filter operations versus the stable
period of operation, which is the
predominant period).
b. Other Filtration Technologies.
Other filtration technologies include
slow sand and diatomaceous earth
filtration. "Technologies and Costs for
the Treatment of Microbial
Contaminants in Potable Water
Supplies, October 1988" by USEPA
(1988) listed research studies indicating
that a well designed and operated plant
using these technologies is capable of 3-
to 4-log removal of Giardia and viruses.
Recent findings appear in Table 2
below.
TABLE 2.—CRYPTOSPORIDIUM AND GIARDIA LAMBLIA REMOVAL EFFICIENCIES
Type of treatment plant
Diatomaceous Earth
Log removal
Giardia >3
Crypt >3
Crypt 4 5
Giardia >3
Crypt >3
Experimental design
Pilot plant at 4.5 to
16.5 degrees C
Full scale plant
Pilot plant, addition of
coagulant increased.
removal beyond.
values shown.
Researcher
Schuller and Ghosh, 91.
Timms et al., 1995
Schuler and Ghosh, 90.
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Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules
c. Multiple Barrier Approach.
The M-DBP Advisory Committee
engaged in extensive discussion
regarding the adequacy of relying solely
on physical removal to control
Cryptosporidium in drinking water
supplies and on the need for
inactivation. There was a substantial
absence of technical consensus on how
to or whether it is currently possible to
adequately measure Cryptosporidium
inactivation efficiencies for various
disinfection technologies. This issue
emerged as a significant impediment to
addressing inactivation in the IESWTR.
As part of the original 1994 proposal,
USEPA included control strategies that
would entail the development of a map
of inactivation efficiencies for
Cryptosporidium. As discussed later in
Section M. of this Notice, adequate
information to develop such a map is
not available at this time. The Advisory
Committee discussion recognized,
however, that inactivation requirements
may be appropriate and necessary under
future regulatory scenarios and that
physical removal by filtration may not
be sufficient under all circumstances or
for all source waters.
As part of the development process
for the long term ESWTR. the Advisory
Committee recommended that USEPA
request comment on a risk-based
proposal for Cryptosporidium
embodying the multiple barrier
approach (e.g., source water protection,
physical removal, inactivation, etc.),
including, where risks suggest
appropriate, inactivation requirements.
In establishing the LTESWTR. the
Committee recommended that the
following issues be evaluated:
—Data and research needs and
limitations (e.g., occurrence,
treatment, viability, active disease
surveillance, etc.);
—Technology and methods capabilities
and limitations;
—Removal and inactivation
effectiveness;
—Risk tradeoffs including risks of
significant shifts in disinfection
practices;
—Cost considerations consistent with
the SDWA;
—Reliability and redundancy of
systems; and
—Consistency with the requirements of
the Act.
3. Advisory Committee
Recommendations and Related Issues
USEPA reiterates its request for
comment on the following
recommendations of the M-DBP
Advisory Committee.
All surface water systems that serve more
than 10,000 people and are required to filter
must achieve at least a 2-log removal of
Ctyptosporidium. Systems which use rapid
granular filtration (direct filtration or
conventional filtration treatment-as currently
defined in the SWTR), and meet the turbidity
requirements described in section H.C. are
assumed to achieve at least a 2-log removal
of Ciyptosporidlum, Systems which use slow
sand filtration and diatomaceous earth
filtration and meet existing turbidity
performance requirements under the SWTR
(less than 1 NTU for the 95th percentile or
alternative criteria as approved by the State)
are assumed to achieve at least 2-logs
removal of Cryptosporidium.
Systems may demonstrate that they
achieve higher levels of physical removal.
C. Turbidity Control
1. Summary of 1994 Proposal as it
Relates to Turbidity Issues and Public
Comments
Finished water turbidity levels are
currently regulated by USEPA under the
SWTR as a treatment technique to
ensure removal of Giardia and viruses.
The SWTR requires systems to monitor
the turbidity of the combined filter
effluent every four hours at each
treatment plant. Systems using direct
filtration or conventional treatment
must achieve a combined filter effluent
turbidity level of no more than 0.5 NTU
in 95% of the measurements in each
month and never exceed 5 NTU. Failure
of individual filters may allow
pathogens to enter the distribution
system. However, the SWTR does not
presently require systems to monitor the
effluent of individual filters.
As a treatment technique, turbidity is
&n indicator of filtration performance.
Treatment plants are, as noted above,
required to meet certain turbidity levels
to meet the removal requirements for
Giardia. Although turbidity is not a
direct indicator of health risk, a very
low turbidity level of the treated water
is in general a good indicator of effective
Cryptosporidium and Giardia oocyst
and cyst removal by rapid granular
filtration. USEPA continues to believe
that turbidity is the most readily
measurable parameter to indicate
filtration treatment effectiveness.
A primary focus of the 1994 proposal
was the establishment of treatment
requirements that would address public
health risks from high densities of
pathogens in poor quality source waters
and from the waterborne pathogen
Cryptosporidium. As discussed earlier
in this Notice, waterborne pathogens
have caused significant disease
outbreaks in the United States.
Approaches outlined in the 1994
proposal included treatment
requirements based on site-specific
concentrations of pathogens in source
water and a proposed 2-log removal
requirement for Cryptosporidium by
filtration.
USEPA also specifically requested
comment on what criteria, if any,
should be included to ensure that
systems optimize treatment plant
performance and on whether any of the
existing turbidity performance criteria
should be modified (e.g., should
systems be required to base compliance
with the turbidity standards on
individual filter effluent monitoring in
lieu of or in addition to monitoring the
confluence of all filters; and should any
performance standard value be
changed). In addition, the Agency
requested comment in the 1994
proposal on possible supplemental
requirements for State notification of
persistent high turbidity levels (e.g.,
broadening the requirements for State
notification of turbidity exceedances);
Some comments suggested and
supported a revised approach to the
IESWTR that would focus on optimizing
existing water treatment processes to
provide insurance against microbial
disease outbreak in the absence of
source water occurrence data. Another
comment suggested that current levels
of treatment, including filtration, have a
sufficient degree of effectiveness in
preventing transmission of
Cryptosporidium in drinking water.
One commenter suggested that
turbidity performance standards should
not be modified until the SWTR has
been further implemented. One
commenter suggested that decreases in
turbidity standards or monitoring after
each filter should be voluntary unless
scientific data demonstrate otherwise.
Another commenter suggested that
individual filters can be evaluated
during sanitary surveys. Several
commenters supported tighter turbidity
standards and monitoring of individual
filters. Suggested turbidity performance
levels included 0.1 or less, or 0.2 NTU
as revised standards. Several
commenters supported monitoring of
individual filters, with one suggesting
backwashing of filters when turbidity
levels increase.
2. New Data and Perspectives
As presented in detail below, the M-
DBP Advisory Committee's
recommendations to the Agency
included tighter turbidity performance
criteria and individual filter monitoring
requirements as part of the IESWTR.
These revised performance criteria,
along with the individual filter
monitoring requirements, would better
enable systems to demonstrate that they
meet a 2 log removal requirement for
Cryptosporidium. Because
Cryptosporidium is exceptionally
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Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules
59499
resistant to inactivation using chlorine,
physical removal by filtration is
extremely important in controlling this
organism. Data presented in the
previous section of this Notice support
modifications to the existing turbidity
requirements under the SWTR to enable
systems to demonstrate diat they meet
the proposed 2 log requirement.
The revised turbidity performance
criteria would also contribute to another
of the lESWTR's key objectives, which
is to establish a microbial backstop to
prevent significant increases in
microbial risk when systems implement
new disinfection byproduct standards
under the Stage 1 DBPR. As indicated
by data presented below, tighter
turbidity performance criteria would
reflect actual current performance for a
substantial percentage of systems
nationally. Revising the turbidity
criteria would effectively ensure that
these systems continue to perform at
these levels (in addition to resulting in
improved performance by systems that
currendy meet die existing criteria but
that operate at levels higher than those
suggested in the Advisory Committee's
recommendations). The other major
component of a microbial backstop
would be provisions for disinfection
profiling and benchmarking, which are
discussed in Section D. of this Notice.
The revisions to the turbidity
provisions (including the individual
filter provisions) recommended by the
Committee would also contribute to the
microbial backstop objective in direct
relationship to the treatment process
itself. The reliability of the disinfection
barrier as a means for preventing
waterborne disease should increase
substantially as a result of these tighter
turbidity provisions because:
—There would be fewer and shorter
periods of elevated turbidity during
which the disinfection barrier could
be compromised; and
—The removal of particulate matter
achieved by the filtration process will
both be higher on average and more
consistent throughout the treatment
cycle, thus putting less burden on the
disinfection barrier.
a. 95th Percentile and Maximum
Turbidity Levels of Composite Filtered
Water.
Three data sets, summarizing the
historical turbidity performance of
various filtration plants, were evaluated
to assess the national impact of
modifying existing turbidity
requirements. This included turbidity
information from the American Water
Works Service Company (AWWSC,
1997), a multi-State data set (which was
analyzed in two sets) (SAIC, 1997), and
information from plants participating in
the Partnership for Safe Water program
(Bissonette, 1997). Only turbidity data
from plants serving populations greater
than 10,000 persons were used. The
analyses also included only plants that
met the current 95th percentile turbidity
standard, 0.5 NTU, and the current
maximum turbidity standard, 5 NTU, in
all months. Each of the data sets was
analyzed to assess the current
performance of plants with respect to
the number of months in which selected
95th percentile and maximum turbidity
levels were exceeded.
The AWWSC is a privately-held
company that owns and operates for
profit about 70 water treatment facilities
located across the country. For this
analysis, die AWWSC data set
(AWWSC, 1997) included one year's
data for 45 plants in 10 States. The
States, witfi number of plants in each
state listed in parentheses, are as
follows: California (1), Connecticut (3),
Iowa (2), Indiana (6), Maryland (1),
Missouri (2), Pennsylvania (24),
Tennessee (1), Virginia (2), and West
Virginia (3). USEPA analyzed die
composite filtered effluent turbidity
data obtained from the AWWSC plants
measured every 4-hours.
The analyses examined two variations
of turbidity data obtained from die
multi-State data set (SAIC, 1997). The
multi-State data set included 86 plants
in 11 states. The States, with number of
plants in each state listed in
parentheses, are as follows: California
(10), Georgia (5), Kansas (9), New Jersey
(5), Ohio (12), Oregon (10), Rhode Island
(6), Texas (9), Wisconsin (8), West
Virginia (6), Wyoming (6). The State
data was analyzed as two data sets,
denoted as State 1 and State 2. The State
1 data set included only plant
information with measurements every 4
hours, comprising slightly more than
half of the State data (47 plants in CA
(10), OR (10), TX (9), WI (6), WY (6),
WV (6)). The State 2 data set was
comprised of both the State 1 data and
other data including plant information
consisting of daily maximum turbidity
values only, altogether 86 plants.
The State 1 data set was expected to
provide a more accurate picture of
typical plant performance among die
plants in the entire State data set
because there were more data points per
plant. However, the State 2 data set
increased regional coverage by
incorporating data from five additional
States (GA, KS, NJ, OH, RI) to reflect
additional geographic variation that may
not have been captured in die State 1
data set.
In order to determine how many of
the systems met lower 95th percentile
turbidity levels based on turbidity
measurements every four hours, the data
from those States in which systems only
report maximum daily values had to be
statistically adjusted. The adjustment is
necessary to take into account die
difference in die number of reported
measurements in a mondi diat can •
exceed a particular level (e.g., 0.3 NTU)
without exceeding the monthly 95th
percentile for that level. (Systems that
report measurements every four hours
can have up to 9 of 180 measurements
(5%) diat exceed die level in a month;
however, there is no way to directly
calculate an equivalent value for
systems that only report daily maximum
values without making some
adjustment.) No adjustment was
necessary for assessing mondily
maximum turbidity levels.
The State 2 analyses adjusted die
monthly 95th percentile turbidity levels
for plants with only daily maximum
data. This was done because die 95th
percentile based on 31 daily turbidity
maximums a montii will overestimate
the 95th percentile based on 186 daily
measures (or measurements every 4
hours). To assess the magnitude of'the
bias, the State 1 data were used to
examine die relationship between die
95th percentile of the daily maximums
and the 95th percentile of the daily
measurements.
The State 2 monthly 95th percentile
analyses were obtained by dividing the
estimated montiily 95th percentiles of
those systems reporting only daily
maximums by a factor of 1.2 to account
for bias. This factor was derived as
follows. The daily maximum was
determined for each day in the State 1
data set and a montiily 95th percentile
(of die 30 or 31 daily maximums) was
determined, i.e., the second largest daily
maximum. The corresponding monthly
95th percentile based on the daily data
was also determined. The ratio of these
two values was then calculated and
summarized across months. The median
ratio across all months was 1.2, with 90
percent of die ratios ranging between 1.0
and 1.9. The analysis used to derive die
adjustment factor examined only plants
that reported six values per day.
The remaining data set included in
the turbidity analysis was of plants
participating in the Partnership for Safe
Water. The Partnership for Safe Water is
a joint venture of several organizations,
including the American Water Works
Association, the Association of State
Drinking Water Administrators, the
Association of Metropolitan Water
Agencies, the National Association of
Water Companies, die American Water
Works Association Research Foundation
and USEPA. These organizations
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Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules
entered into a voluntary "partnership"
with the nation's drinking water
filtration plants treating surface water to
tighten treatment practices and
operational controls to reduce the risk
from Cryptosportdium and other
waterborne pathogens. The Partnership
approach, described in the "Partnership
for Safe Water Voluntary Water
Treatment Plant Performance
Improvement Program Self-Assessment
Procedures" (USEPAetal. 1995), is
based on USEPA's Composite
Correction Program (CCP). The CCP is a
voluntary program which is described
in detail In the handbook Optimizing
Water Treatment Plant Performance
Using the Composite Correction
Program-USEPA/625/6-91/027. The
Partnership for Safe Water utility
membership consists of 199 utilities
representing almost 280 water treatment
plants. These plants serve'
approximately 80 million persons. The
Partnership consists of four phases with
each phase providing tools and
methodologies to assist utilities in
progressing toward a higher quality
finished water. The following data
summarizes turbidity performance
based on 4-hour measurements reported
by the Partnership utilities for 12
months overlapping 1995 and 1996. The
data represents a composite of
Partnership utilities that have
completed varying phases of
Partnership activities, ranging from
having just joined to having progressed
well into the self-assessment phase
(phase 3). All data were derived from
the 1997 Partnership for Safe Water
Annual report (Bissonette, 1997).
The results of the analyses of all of the
data sets are shown in Tables 3 and 4.
Tables 3 and 4 indicate the extent to
which plants, as currently operated, are
meeting different turbidity levels.
Conversely the data indicate the portion
of utilities which might need to alter
existing practice in order to meet lower
turbidity limits, if such limits were
required through regulation.
Table 3 is organized to reflect the
extent to which utilities are currently
meeting monthly 95th percentile
turbidity limits, assuming that
compliance with such limits is
determined as currendy done under the
existing monthly 95th percentile
standard of < 0.5 NTU. For example.
Table 3 indicates that 19.1 percent
(based on the Partnership data set) and
34.9 percent (based on the State 2 data
set) exceed a monthly 95th percentile
turbidity limit of 0.3 NTU at least one
month during the year for which data
were collected. Table 3 also indicates
the extent to which utilities meet a
particular limit for multiple months of
the year (i.e., for at least 3 months and
for at least 6 months). The frequency in
months by which utilities exceed a
particular monthly turbidity limit could
influence the extent of treatment that
might be needed to achieve compliance
through out the year.
The Technical Work Group (TWG)
which provided technical advice to the
Advisory Committee made the following
recommendations for estimating
national compliance forecasts.
(1) The State 2 data set could be used
as a reference point for estimating
potential compliance burdens for
systems serving less than 100,000
people. The Partnership data could be
used as a reference point for estimating
potential compliance burdens for
systems serving greater than 500,000
people. For systems serving between
100,000 and 500,000 people, the average
of the percentages of systems not
meeting a particular limit reflected by
the Partnership and State 2 data could
be used for estimating compliance
burdens.
(2) Estimates for systems needing to
make changes to meet a turbidity
performance limit of < 0.3 NTU should
be based on the ability of systems
currently being able to meet a 0.2 NTU
as reflected in Table 3. This assumption
would also take into account a utility's
concern with possible turbidity
measurement error.
For example, for systems serving less
than 100,000 people, the TWG assumed
that 51.7 percent of the systems could
be expected to make treatment changes
to consistently comply with a monthly
95th percentile limit of 0.3 NTU.
Similarly, for systems serving over
500,000 people, the TWG assumed that
41.7 percent could be expected to make
treatment changes to comply with a 0.3
NTU regulatory limit.
Table 4 is organized to reflect the
extent to which utilities meet different
monthly maximum turbidity limits (i.e.,
all measurements taken during the
month must be below the indicated
limit). For example, Table 4 indicates
that 6 percent of the plants (based on
State 2 Partnership data) are currently
exceeding a monthly maximum limit of
1.0. The data in Table 4 were considered
for evaluating possible national impacts
of lowering the current maximum limit
of 5 NTU to some lower value.
Regarding maximum turbidity levels,
the Advisory Committee also discussed
filtered water turbidity levels with
respect to the cryptosporidiosis
outbreak in Milwaukee in 1993. Some
members indicated concern that filtered
water turbidities associated with the
outbreak apparently were significantly
lower than the current maximum
turbidity level of 5 NTU. Indications are
that the turbidity levels were at about 2
NTU (MacKenzie et al., 1994; Fox and
Lytle., 1996).
TABLE 3.—NUMBER AND PERCENT OF PLANTS THAT EXCEEDED MONTHLY 95TH PERCENTILE TURBIDITY LIMITS IN AT
LEAST N MONTHS our OF 12
Turbidity limit
0.1
State 2
AWWSC
Partnership
0.2
State 2
AWWSC
Partnership
0.3
State 2
AWWSC
Partnership
04
State 2
AWWSC
Data source
State 1
69
33
177
State 1
44
12
98
State 1
30
6
45
State 1
9
3
At least 1 month
Num
34
80.2
73.3
75.3
17
51.2
26.7
41.7
10
34.9
13.3
19.1
3
10.5
6.7
Pet
72.3
59
24
136
36.2
29
7
51
21.3
11
1
17
6.4
1
0
At least 3 months
Num
28
68.6
53.3
57.9
9
33.7
15.6
21.7
3
12.8
2.4
7.2
0
1.2
0.0
Pet
59.6
51
15
100
19.1
15
2
27
6.4
3
0
7
0.0
0
0
At least 6 months
Num
24
59.3
33.3
42.6
2
17.4
4.4
11.5
0
3.5
0.0
3.0
0
0.0
0.0
Pet
51.1
4.3
0.0
0.0
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Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules 59501
TABLE 3.—NUMBER AND PERCENT OF PLANTS THAT EXCEEDED MONTHLY 95TH PERCEMTILE TURBIDITY LIMITS IN AT
LEAST N MONTHS our OF 12—Continued
Turbidity limit
Partnership
Data source
22
At least 1 month
Num
9.4
Pet
5
At least 3 months
Num
2.1
Pet
3
At least 6 months
Num
1.3
Pet
Population served >10,000. State 1 (4-hour daily data from 47 plants): 10 CA, 10 OR, 9 TX, 6 Wl, 6 VW, 6 WY. State 2 (86 plants including
State 1 data and daily maximums * from additional plants): 10 CA, 5 GA, 9 KS, 5 NJ, 12 OH, 10 OR, 6 Rl, 9 TX, 8 Wl 6 WV 6 WY AWWSC-
45 plants: 1 CA, 3 CT, 2 IA, 6 IN, 1 MD, 2 MO, 24 PA, 1 TN, 2 VA, 3 WV. Partnership for Safe Water 235 plarts. *For plants with only daily
maximums, the monthly 95th percentile was estimated as the 95th percentile of the daily maximums divided by 1.2. The adjustment was done to
account for the potential bias of taking the 95th percentile of daily maximums, and was based on the relationship observed in the State 1 data
between the 95th percentile of the daily maximums and the 95th percentile of the 4-hour data.
TABLE 4.—NUMBER AND PERCENT OF PLANTS THAT EXCEEDED MONTHLY MAXIMUM TURBIDITY LIMITS IN AT LEAST N
MONTHS our OF 12
Maximum turbidity limit
0.3
State 2
AWWSC
Partnership
0.5
State 2
AWWSC
Partnership
1.0
State 2
AWWSC
Partnership
2.0
State 2
AWWSC
Partnership
Data source
State 1
69
24
129
State 1
35
12
65
State 1
6
4
16
State 1
2
0
7
At least 1 month
Num
36
80.2
53.3
54.9
18
40.7
26.7
27.7
1
7.0
8.9
6.8
1
2.3
0.0
3.0
Pet
76.6
36
10
72
38.3
7
3
20
2.1
0
0
4
2.1
0
0
2
At least 3 months
Num
15
41.9
22.2
30.6
3
8.1
6.7
8.5
0
0.0
0.0
1.7
0
0.0
0.0
0.9
Pet
31.9
15
4
37
6.4
1
0
5
0.0
0
0
2
0.0
0
0
1
At least 6 months
Num
6
7.4
8.9
15.7
1
1.2
0.0
2.1
0
0.0
0.0
0.9
0
0.0
0.0
0.4
Pet
12.8
2.1
0.0
0.0
b. Individual Filter Performance.
During a |urb.id,ity spike,, significant
amounts of partipulatg matter (including
oocysts, if present) may paps through
the filter. Figure, 3 presents the turbidity
levels over tinje qf a typical 'filter. The
greatest potential for a. peak (and thus,
pathogen breaic-through) is near the
beginning of the filter run after filtered
backwash or start up of operation
(Amirtharajah 1988; Bucklinetal. 1988;
Cleasby 1990; and Hall and Croll 1996).
Various factors effect the duration and
amplitude of filter spikes, including
sudden changes to the flow rate through
die filter, treatment of the filter
backwash water, filter to waste
capability, and site-specific water
quality conditions. The M-DBP
Advisory Committee also discussed the
need to control turbidity spikes in order
to limit the number of oocysts passing
through the filter.
BILLING CODE 656O-SO-P
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59502 Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules
Filter
R ip en Ing
Spike
z
Sy
•a
3
I-
J
(Y
\ Turbidity
1 Breakthrough
H ours
Figure 3. P lot of Turbidity Profile
BILLING CODE 6560-50-C
c. Turbidity Measurement.
Turbidity is a measure of light scatter
that is affected by the size distribution
and shape of suspended particles in the
water. Four methods are commonly
used to measure turbidity and all are
approved for use under die SWTR. They
include the Nephelometric Method
listed In 2130B of the Standard Methods
for the Examination of Water and
Wastewater, Standard Test Method for
Turbidity of Water ASTM (1990)
D1889-94, the Nephelometric Method
in 180.1 of USEPA-600/R-93-100 and
the Great Lakes Instruments Method 2
(see section 141.74 (a) (1)).
Turbidimeters which measure
turbidity commonly consist of the
following components: (1) a light source
and lenses and odier optical devices to
project the light beam at the sample
container and to direct the scattered
light to the detector; (2) a transparent
cell that contains the water to be
measured; (3) light traps within the
sample chamber that minimize the
amount of stray light that reaches the
detector; and (4) a meter that indicates
the intensity of the light reaching the
detector. While turbidity measurement
has long been recognized as a means for
evaluating treatment performance for
removal of particulate matter (which
include microorganisms), issues remain
pertinent to the accuracy and precision
of the measurement (Hart et al. 1992;
Sethi et al. 1997).
Large tolerances in instrument design
criteria, intended to promote
competition among instrument
manufacturers, have lead to
turbidimeters with significantly
different design features being available
on the market. Turbidimeters with
different designs (but within the design
specifications of Standard Methods),
calibrated according to manufacturer's
recommendations, have been shown to
provide different turbidity readings for
a given suspension (Hart et al. 1992).
The significance of this phenomenon as
it might pertain to the same water with
changing turbidities over time or
different waters in the U.S. is not
known. Therefore, narrowing
instrument design criteria could reduce
variation of turbidity measurement but
the best direction that such change
should take is not yet apparent.
Calibration procedures also affect
turbidity measurements. Calibration
typically involves placing a quantity of
a standard suspension in the
turbidimeter and dien adjusting the
response so that the meter gives a
reading equal to die turbidity value
assigned to title standard. Instruments
that are calibrated with currently
approved different standard
suspensions can yield different turbidity
measurements on the same water (Hart
et al. 1992). The significance of this
phenomenon as it might pertain to the
same water with changing turbidities
over time or different waters in the U.S.
is also not known. While narrowing
specifications for current calibration
procedures could reduce variation of
turbidity measurements, the best
direction that such change should take
is not yet apparent.
Other factors diat may affect turbidity
measurement include procedures used
to prepare and wipe the sample cell and
use of sample degassing procedures.
The extent to which all of the above
factors, collectively, affect turbidity
measurement is not known. However,
past performance evaluation (PE)
studies conducted by USEPA provide
some indication of accuracy and
precision of turbidity measurements
among different laboratories for a
common synthetically prepared water.
In PE studies, PE samples with known
turbidity levels are sent to participating
laboratories (who are not informed of
the turbidity level). Laboratories
participating in tiiese studies used
turbidimeters from various
manufacturers and conducted their
analysis in accordance with calibration
and analytical procedures they are
familiar with. Thus, die variability of
die results reflect differences resulting
from using different turbidimeter
models and methods and the effects of
different laboratory procedures. Table 5
summarizes results from PE studies
conducted at turbidity levels close to
the SWTR turbidity performance limit
of 0.5 NTU. The Relative Standard
Deviation (RSD) is die Standard
Deviation divided by the mean. It
appears tiiat die RSD at turbidity levels
considered in these PE studies are
slightly below 20%. (A RSD of 20%
implies diat 95% of one-time turbidity
measurements made by different
laboratories would fall widiin 40% of
die mean. The RSD for an individual
laboratory, making numerous
measurements on a given sample water
would be expected to be significantly
less than that achieved among different
laboratories (using a variety of
turbidimeters as indicated in Table 5).
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Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules
59503
TABLE 5.—USEPA PERFORMANCE EVALUATION RESULTS OF TURBIDITY MEASUREMENTS (USEPA 1997d)
[Turbidity readings are expressed in NTU, and Relative Standard Deviation in %]
Study No.
34 USEPA/State
34 All Lab
23 USEPA/State
25 USEPA/State
25 All Lab
25 USEPA/State
25 All Lab
22 USEPA/State
True Turb.
.720
.720
.650
.600
.600
.450
.450
.350
No. of
samples
54
1503
24
28
708
29
707
52
Mean
.752
.744
659
.585
.597
463
481
406
Relative
S D
160
158
10 1
138
160
205
195
16 1
No data is yet available on
measurement performance from PE
studies at levels less than 0.3 NTU. A
major concern expressed by participants
among the Advisory Committee is the
ability to reliably measure low turbidity
levels. The TWG assumed that if
systems operated to achieve a turbidity
limit of less than 0.2 NTU 95 percent of
the time, this would provide an
adequate margin of safety from
variability in treatment performance and
turbidity measurement error, to
consistendy meet a turbidity limit of 0.3
NTU.
USEPA intends to conduct two PE
studies with true turbidities ranging
from 0.1 to 0.3 NTU. One study is
planned to begin no later than the end
of January 1998 and the other study
within 6 months thereafter. These new
studies will provide an indication of
accuracy and precision of turbidity
measurements at lower levels than
previously examined. Measurements by
on-line turbidimeters will also be
evaluated. :
On-line monitoring issues: For
expedience, on-line turbidimeters are
often calibrated against a bench
instrument that has been accurately
calibrated by comparing the turbidity
level in a water sample. However, at
regular intervals they need to be taken
offline and calibrated, as for bench
instruments, by pouring the prepared
standard suspension into the chamber of
the instrument. On-line instruments
must be inspected regularly to remove
air bubbles and accumulated debris.
Fluctuations in continuous
measurements do not necessarily signify
a decrease in water treatment
performance. Fluctuations in
continuous measurements should be
investigated since they may be due to
air bubbles, debris or a temporary
disturbance due to a change in the flow
rate of sample water flow through the
turbidimeter. To address the
contingency of such phenomenon, the
Advisory Committee recommended,
based on advice from the Technical
Work Group, that turbidity spikes
should be defined on the basis of at least
2 consecutive measurements taken over
some interval of time (e.g., 15 minutes).
There is no standard design
specification for on-line turbidimeters
regarding chamber size and
recommended flow rate. Thus, turbidity
spikes of the treated water will be
reflected with a delay of a few seconds
to a few minutes, depending on
chamber volume and flow rate of the
turbidimeter. A turbidity peak measured
by a turbidimeter with a large chamber
volume and small flow rate will result
in slightly reduced peak.
3. Advisory Committee
Recommendations and Related Issues
USEPA reiterates its request for
comment on the following
recommendations of the M-DBP
Advisory Committee.
1. Turbidity Performance Requirements.
For all surface water systems that use
conventional treatment or direct filtration,
serve more than 10,000 people, and are
required to filter: (a) the turbidity level of a
system's combined filtered water at each
plant must be less than or equal to 0.3 NTU
in at least 95 percent of the measurements
taken each month and, (b) the turbidity level
of a system's combined filtered water at each
plant must at no time exceed 1 NTU. For
both the maximum and the 95th percentile
requirements, compliance shall be
determined based on measurements of the
combined filter effluent at four-hour
intervals.
2. Individual Filter Requirements. All
surface water systems that use rapid granular
filtration, serve more than 10,000 people, and
are required to filter shall conduct
continuous monitoring of turbidity for each
individual filter and shall provide an
exceptions report to the State on a monthly
basis. Exceptions reporting shall include the
following: (1) any individual filter with a
turbidity level greater than 1.0 NTU based on
2 consecutive measurements fifteen minutes
apart; and (2) any individual filter with a
turbidity level greater than 0.5 NTU at the
end of title first 4 hours of filter operation
based on 2 consecutive measurements fifteen
minutes apart. A filter profile will be
produced if no obvious reason for the
abnormal filter performance can be
identified.
If an individual filter has turbidity levels
greater than 1.0 NTU based on 2 consecutive
measurements fifteen minutes apart at any
time in each of 3 consecutive months, the
system shall conduct a self-assessment of the
filter utilizing as guidance relevant portions
of guidance issued by the Environmental
Protection Agency for Comprehensive
Performance Evaluation (CPE). If an
individual filter has turbidity levels greater
than 2.0 NTU based on 2 consecutive
measurements fifteen minutes apart at any
time in each of two consecutive months, the
system will arrange for the conduct of a CPE
by the State or a third party approved by the
State.
3. State Authority: States must have rules
or other authority to require systems to
conduct a Composite Correction Program
(CCP) and to assure that systems implement
any follow-up recommendations that result
as part of the CCP.
In reference to the above
recommendations, EPA also requests
comment on what would or would not
constitute an obvious reason for
abnormal filter performance. The
Agency also requests comment on how
much time a system should have to
conduct a self-assessment of the filter
and how much time a system should
have to arrange for die conduct of a CPE
under circumstances such as described
in the recommendations.
USEPA also requests comment on
whether there are particular filters
currently in operation in the United
States for which specific guidance may
be needed with regard to individual
filter monitoring. For example, some
members of the M-DBP Advisory
Committee suggested that special
guidance be developed for unique
filtration devices made by Infilco
Degremeont (previously made by
Aldridge). These devices consist of
multi-celled filters with a traveling
bridge-automated back washing unit
that are not conducive to individual cell
monitoring.
USEPA also requests comment
regarding existing SWTR provisions for
lime softening plants that have very low
-------
59504
Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules
turbidity in source waters. The existing
SWTR allows States to set numerically
higher standards up to 1 NTU in 95
percent of samples taken per month for
conventional treatment and direct
filtration plants if the State determines
that on-site studies demonstrate at least
99.9 percent overall removal and/or
inactlvation of Giardia cysts. (54 FR
27503). In the SWTR (54 FR 27486), the
Agency notes that actual demonstrations
"(e.g. with pilot plant study results)" are
not required for the State to determine
when minimum performance
requirements at Ore higher turbidity
level might be appropriate for a
particular system. The SWTR states:
Instead, the State's determination may be
based upon an analysis of existing design and
operating conditions (e.g. adequacy of
treatment prior to nitration, percent turbidity
removal across the entire treatment train,
stringency of disinfection) and/or
performance relative to certain water quality
characteristics (e.g, microbiological analysis
of the filtered water, particle size counts In
water before and after filtration). The State
may wish to consider such factors as source
water quality and system size In determining
the extent of analysis necessary. (54 FR
27503).
Committee members raised situations
where filtration plants have been
designed for specific source water
quality characteristics such as high
alkalinity and extremely low turbidity
water (e.g. 0.1 to 0.5 NTU). In systems
with such source waters, turbidity levels
from the filters may actually be higher
than in the source waters due to
reactions from chemicals added mainly
for purposes other than source water
particle removal. Lime softening plants
operating under certain conditions,
depending upon process configuration
and raw water characteristics or when
flocculation conditions change, may
periodically experience a carry over of
extremely fine calcium carbonate or
magnesium hydroxide particles. These
fine particles may pass through filters
thereby resulting in artificially elevated
effluent turbidity levels. If turbidity
performance criteria are tightened under
the IESWTR some plants may have
difficulty meeting these criteria but still
achieve substantial removal of Giardia
lamblla, Cryptosporidium parvum, and
viruses. As reflected in the 1989 SWTR,
USEPA believes that in cases where
lime softening is practiced and source
water turbidity levels are low,
provisions for alternative treatment
performance criteria (i.e., in lieu of
turbidity) may be appropriate.
As in the present SWTR, USEPA
believes that demonstrations of
equivalent protection need not be based
on actual demonstrations (e.g. pilot
plant study results). Instead the State's
determination can be based on the
factors cited at 54 FR 27503 as quoted
above. Other factors related to source
water microbial quality (e.g. pristine
source water, source water protection
programs, microbial monitoring results,
bank filtration) may be appropriate for
such determinations.
USEPA requests comment on the
appropriateness of continuing existing
provisions that provide States the
flexibility of approving higher turbidity
levels up to 1 NTU in 95 percent of
samples per month and up to 2 NTU
maximum turbidity for such plants, and
additionally seeks comments on:
• What types of plants might fall in this
category (e.g. softening plants designed for
color and hardness removal with very low
turbidity source waters);
• What demonstrations of equivalent
protection from Giardia lamblia,
Cryptosporidium parvum, and viruses are
appropriate (e.g. microbiological analysis of
the filtered water, monitoring results for
protozoans, watershed control, wellhead
protection programs);
• What additional or alternative
requirements States might place on such
systems to insure the objective of equivalent
protection from Giardia lamblia,
Cryptospoiidium parvum, and viruses (e.g.
regular monitoring for protozoans in source
and or filtered water, or for other water
quality parameters, watershed control, well
head protection programs);
• Allowing systems to acidify turbidity
samples when calcium carbonate carry-over
exists to obtain true turbidity readings; and
• The appropriateness of including source
water microbial quality measurements or
surrogates as part of a State determination of
equivalent protection when considering
whether to authorize higher operating
turbidity levels.
D. Disinfection Benchmark for Stage 1
DBPMCLS
A fundamental principle of the 1992-
93 regulatory negotiation which was
reflected in the 1994 proposal for the
IESWTR was that new standards for
control of byproducts must not result in
significant increases in microbial risk.
This principle was also one of the
underlying premises of the M-DBP
Advisory Committee's deliberations,
i.e., that existing microbial protection
must not be significantly reduced or
undercut as a result of systems taking
the necessary steps to comply with the
Stage 1 DBPR. The Advisory
Committee's recommendations to meet
this key objective are discussed in this
section.
The approach outlined below
represents the recommendation of the
Advisory Committee to develop a
mechanism that is designed to assure
that pathogen control is maintained
while the Stage 1 DBPR provisions are
implemented. Briefly, the disinfection
benchmark addresses the three issues of
who must gather the necessary
information to evaluate current
practices, how the benchmark operates,
and finally, how the system and the
State work together to assure that
microbial control is maintained.
Based on data provided by systems
and reviewed by the TWG, the baseline
of microbial inactivation (expressed as
logs of Giardia lamblia inactivation)
demonstrated high variability.
Inactivation varied by several logs on a
day-to-day basis at any particular
treatment plant and by as much as tens
of logs over a year due to changes in
water temperature, flow rate (and
consequently contact time), seasonal
changes in residual disinfectant, pH,
and disinfectant demand (and
consequently disinfectant residual).
There were also differences between
years at individual plants.
To address these variations, the TWG
developed an approach for a system to
use to characterize disinfection practice;
the procedure is called profiling. In
essence, this approach allows a plant to
chart or plot its daily levels of Giardia
inactivation on a graph which, when
viewed on a seasonal or annual basis,
represents a "profile" of the plant's
inactivation performance. The system
can use the profile to develop a baseline
or benchmark of inactivation against
which to measure possible changes in
disinfection practice. This approach
makes it possible for a plant that may
need to change practice to meet DBF
MCLs to assure no significant increase
in microbial risk. It provides the
necessary tool to allow plants to project
or measure the possible impacts of
potential changes in disinfection. Only
certain systems would be required to
develop a profile and keep it on file for
State review during sanitary surveys,
and only a subset of those required to
develop a profile would be required to
submit it to the State as part of a
package submitted when the system is
making significant changes to its
disinfection practice.
USEPA reiterates its request for
comment on the following
recommendations of the M-DBP
Advisory Committee that address the
three questions outlined above: (1) who
should develop a profile, (2) how a
profile is actually generated, and (3)
how the profile will be used.
1. Applicability
Systems would be required to prepare
a disinfection profile, if at least one of
the following criteria are met:
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Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules
59505
(1) TTHM levels are at least 80% of the
MCL (0.064 mg/1) as an annual average for
the most recent 12 month compliance period
for which compliance data are available prior
to November 1998 (or some other period
designated by the State). Monitoring would
be in accordance with current TTHM
requirements.
(2) Haloacetic acid (HAAS) levels are at
least 80% of the MCL (0.048 mg/1) as an
annual average for the most recent 12 month
period for which data are available (or some
other period designated by the State). In
connection with HAAS monitoring, the
following provisions apply:
(a) Systems that have collected HAAS data
under the ICR must use those data to
determine the HAAS level, unless the State
determines that there is a more representative
annual data set.
(b) If the system does not have four
quarters of HAAS data by the end of 90 days
following the IESWTR promulgation date, the
PWS must conduct HAAS monitoring for
four quarters. This monitoring must comply
with the monitoring requirements included
in the DBF Stage 1 rule.
CThe Advisory Committee
recommended a value of 80% of the
MCL because available data indicated
that DBF levels varied from year to year
due to many factors (e.g., changes in
source water quality, changes in water
demand). The Committee believed that
targeting a level 20% below the MCL
would include most systems that would
be expected to make changes to comply
with the TTHM and HAAS MCLs on a
continuing basis. Also, USEPA
previously considered this target level at
the recommendation of the 1992 reg-neg
committee, to evaluate DBF Stage 1
compliance forecasts and costs, based
upon the judgement that most facilities
will take additional steps to ensure
continuing MCL compliance if they are
at or above these levels.)
2. Developing the Profile and
Benchmark
As oudined above, profiling is the
characterization of a system's
disinfection practice over a period of
time. The system can create the profile
by conducting new daily monitoring or
by using "grandfathered" data (as
explained below). A disinfection profile
consists of a compilation of daily
Giardia lamblia log inactivations (or
virus inactivations under conditions to
be specified in die final rule), computed
over die period of a year, based on daily
measurements of operational data
(disinfectant residual concentration(s),
contact time(s), temperature(s), and
where necessary, pH(s)).
Grandfadiered data are those
operational data that a system
previously collected at a treatment plant
during the course of normal operation.
These data may or may not have been
used previously for compliance
determinations with the SWTR. Those
systems that have all necessary data to
determine profiles, using operational
data collected prior to promulgation of
the IESWTR, would be able to use up to
three years of operational data in
developing profiles. Grandfadiered
operational data should be substantially
equivalent to operational data that
would be collected under diis rule.
Those systems that do not have three
years of operational data to develop
profiles would have to conduct
monitoring to develop die profile for
one year beginning no later tiian 15
months after IESWTR promulgation. If
die PWS has existing operational data to
develop profiles, it would have to use
those data to develop profiles for the
years prior to die IESWTR
promulgation.
In order to develop die profile, a
system would have to:
—Measure disinfectant residual
concentration (C, in mg/1) prior to
entrance into distribution system and
just prior to each additional point of
disinfectant addition, whedier witii
die same or a different disinfectant.
—Determine contact time (T, in
minutes) during peak flow conditions.
T can be based on either a tracer study
or assumptions based on contactor
geometry and baffling. However,
systems would have to use the same
mediod for both grandfatiiered data
and new data.
—Measure water temperature (° C).
—Measure pH (for chlorine only).
The system would then have to
convert operational data to log
inactivation values for Giardia (and
viruses when chloramines or ozone
used as primary disinfectant).
—Determine CTacwai for each
disinfection segment.
—Determine CT^.g (i.e., 3-logs
inactivation) from tables in die
SWTR/IESWTR using temperature
(and pH for chlorine) for each
disinfection segment. [NOTE: USEPA
may redesign the tables so that no
conversion is necessary (i.e., die
tables will reflect a CTw (1-log)
value.]
—For each segment, log inactivation =
(CTac,/CT99.9)x3.0.
A log inactivation benchmark would
then be calculated as follows:
1. Calculate die average log
inactivation for each calendar mondi.
2. Determine die calendar month widi
die lowest average log inactivation.
3. The lowest average month becomes
die critical period for that year.
4. If data from multiple years are
available, die average of critical periods
for each year becomes the benchmark.
5. If only one year of data is available,
die critical period for diat year is the
benchmark.
3. State Review
The State would review disinfection
profiles as part of its periodic sanitary
survey. If a system diat is required to
develop a disinfection profile
subsequently decides to make a
significant change in disinfection
practice, it would have to consult widi
die State before implementing such a
change. Significant changes would be
defined as: (1) moving die point of
disinfection, (2) changing the type of
disinfectant, (3) changing the
disinfection process, or (4) making any
other change designated as significant
by die State. Supporting materials for
such consultation would have to
include a description of die proposed
change, die disinfection profile, and an
analysis of how die proposed change
will affect die current disinfection
benchmark.
4. Guidance
USEPA, in consultation widi
interested stakeholders, will develop
guidance for States and systems on how
to develop and evaluate disinfection
profiles, how to identify and evaluate
significant changes in disinfection
practices, and guidance on moving die
point of disinfection from before the
point of coagulant addition to after the
point of coagulant addition. USEPA will
also develop guidance for systems diat
would be required to develop a profile
based on virus inactivation instead of
Giardia lamblia inactivation. Guidance
will be available when die IESWTR is
promulgated.
5. Request for Public Comment
USEPA requests comment on all
aspects of die recommendation oudined
above and any alternative suggestions
diat stakeholders or other interested
parties may have. Commenters may
want to focus particular attention on die
following issues:
—Applicability requirements,
—Characterization of disinfection
practices and components (e.g.,
monitoring, analysis),
—Use of TTHM and HAAS data from
die same time period instead of
TTHM data from one year and HAAS
data from another,
—Definition of significant changes to
disinfection practice,
—Different approaches to evaluating
possible changes in disinfection
practice against a disinfection profile,
and
—Whether the use of grandfathered
data, if available, should be
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mandatory for profiling and
benchmarking.
E. Definition of Ground Water Under the
Direct Influence of Surface Water
(GWJDI)—Inclusion of
Cryptosporidium In the Definition
I. Summary of 1994 Proposal and
Public Comments
The July 29,1994, Federal Register
notice proposed to amend the SWTR by
including Cryptosporidium in the
definition of a GWUDI system. Under
the rule, a system using ground water
considered vulnerable to
Cryptosporidlum contamination would
be subject to the provisions of die
SWTR. USEPA proposed that this
determination be made by the State for
individual sources using State-
established criteria.
The 1994 proposed IESWTR also
requested comment on revisions to
USEPA's guidance on this issue.
Cryptosporidium oocysts are smaller
than Glardia cysts and may have
substantially different hydrodynamic
behavior in ground water due to their
smaller size and perhaps also due to a
difference in charge distribution on die
outer surface of die oocyst. USEPA
guidance for the determination of
GWUDI suggests mediods that may be
insensitive to this differing
hydrodynamic behavior in ground
water.
Almost all commenters agreed that
Cryptosporidium should be added to the
definition. Only one commenter clearly
opposed the addition without caveat,
maintaining that problems with die
analytical metiiods for die recovery and
enumeration of viable organisms and
uncertainties associated with risk
assessment should preclude its
addition. One commenter contended
that Cryptosporidium should be
included only if USEPA addresses die
amount of natural disinfection at each
site and defines treatment effectiveness,
especially coagulant use, for GWUDI
systems. One commenter believed diat
the definition of Cryptosporidium
should be made at die species level, e.g.
Cryptosporidlum parvum, because otiier
species were not padiogenic to humans.
One commenter was concerned about
the Microscopic Paniculate Analysis
(MPA), one of die methods diat USEPA
Identifies in guidance as being suitable
for making GWUDI determinations. As
part of tills method, a microscopic
examination is made of die ground
water to determine whetiier insect parts,
plant debris, rotifers, nematodes,
Glardia lamblia, and other material
associated with the surface or near
surface environment are present. The
commenter claimed that die MPA has
analytical method problems similar to
those associated witii die recovery of
cysts and oocysts from environmental
samples and suggested that die method
should undergo additional testing witii
positive and negative controls and with
performance evaluation samples.
2. Overview of Existing Guidance
USEPA issued guidance on the MPA
in October 1992 as die Consensus
Method for Determining Groundwater
Under die Direct Influence of Surface
Water Using Microscopic Particulate
Analysis. Additional guidance for
making GWUDI determinations is also
available (USEPA, 1994e,f). Since 1990,
States have acquired substantial
experience in making GWUDI
determinations and have documented
their approaches (Massachusetts
Department of Environmental
Protection, 1993; Maryland, 1993;
Sonoma County Water Agency, 1991).
Guidance on existing practices
undertaken by States in response to die
SWTR may also be found in die State
Sanitary Survey Resource Directory,
joindy published in December 1995 by
USEPA and die Association of State
Drinking Water Administrators.
AWWARF has also published guidance
(Wilson etal., 1996).
3. Summary of New Data and
Perspectives
Most recently, Hancock et al. (1997)
used the MPA test to study die
occurrence of Giardia and
Cryptosporidium in die subsurface.
They found diat. in a study of 383
ground water samples, die presence of
Giardia correlated witii die presence of
Cryptosporidium. The presence of both
pathogens correlated witii die amount of
sample examined but not with the
month of sampling. There was a
correlation between source depth and
occurrence of Giardia but not
Cryptosporidium. The investigators also
found no correlation between the
distance of the ground water source
from adjacent surface water and die
occurrence of either Giardia or
Cryptosporidium. However, they did
find a correlation between distance from
a surface water source and generalized
MPA risk ratings of high (high
represents an MPA score of 20 or
greater), medium or low, but no
correlation was found with the specific
numerical values diat are calculated by
the MPA scoring system.
USEPA is interested in an expanded
discussion of MPA performance. The
work cited here is preliminary
information and represents the only
data provided to USEPA so far. USEPA
is considering severed analytical
activities to address possible changes in
the GWUDI determination guidance.
These changes are as follows:
• Change die MPA methodology to
include a score for Cryptosporidium
oocysts in die risk rating method.
• Conduct additional comparison of
MPA scores with cyst and oocyst
recovery to evaluate the performance of
MPA as an indicator method (e.g.,
Schulmeyer, 1995).
• Conduct additional MPA
performance evaluation testing (witii
both positive and negative controls).
• Compare MPA scores and cyst/
oocyst recovery in horizontal collector
wells and vertical wells to determine if
additional guidance for horizontal
collector wells is needed.
4. Request for Public Comment
USEPA is continuing to consider
inclusion of Cryptosporidium in die
definition of GWUDI. USEPA requests
further comment on this issue as well as
on issues outlined above pertaining to
guidance for GWUDI determinations.
F. Inclusion of Cryptosporidium in
Watershed Control Requirements
1. Summary of 1994 Proposal and
Public Comments
USEPA proposed to extend the
existing watershed control requirements
for unfiltered systems to include the
control of Cryptosporidium. This would
be analogous to and build upon the
existing requirements for Giardia
lamblia and viruses; Cryptosporidium
would be included in the watershed
control provisions wherever Giardia
lamblia is mentioned. USEPA also
proposed requiring a State, as a
condition of primacy, to describe how it
would judge the adequacy of watershed
control programs for Cryptosporidium
as well as Giardia lamblia and viruses
in the source water.
Several commenters to die proposed
rule specifically supported inclusion of
Cryptosporidium in watershed control.
Others supported watershed control
programs in general without specifically
articulating an opinion on
Cryptosporidium. One commenter
specifically opposed the inclusion of
Cryptosporidium in watershed control
program, maintaining that other avenues
of watershed control could be promoted
without including this organism in the
control plan. Another commenter
opposed including Cryptosporidium
because environmental sources of
Giardia and Cryptosporidium were not
sufficientiy understood. This
commenter also opposed the
requirement to include Cryptosporidlum
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59507
in State watershed control program
protocols as a condition of primacy.
Other comments included: (1)
Systems need to be informed of the
nature of upstream pathogen sources
and changes in upstream water quality
in a timely manner, (2) watershed
characteristics should not be the sole
basis for determining water treatment
strategies, (3) upstream sewage
discharges should be prohibited and
cattle farming and feedlots prohibited or
substantially limited in a watershed,
and (4) watershed control programs
should be scientifically based,
educational, and voluntary. One
commenter contended that die burden
of contamination on the watershed
should not fall to the drinking water
systems, and that better coordination on
regulations is needed between the
USEPA's drinking water and wastewater
programs.
2. Overview of Existing Guidance
The SWTR specifies the conditions
under which a system can avoid
filtration (40 CFR 141.71). These
conditions include good source water
quality, as measured by concentrations
of coliforms and turbidity, disinfection
requirements; watershed control;
periodic on-site inspections; the absence
of waterborne disease outbreaks; and
compliance with the Total Coliform
Rule and the MCL for TTHMs.
The watershed control program under
the SWTR must minimize the potential
for source water contamination by
Giardia lamblia and viruses. This
program must include a characterization
of the watershed hydrology
characteristics, land ownership and
activities which may have an adverse
effect on source water quality. The
SWTR Guidance Manual (USEPA,
1991a) identifies both natural and
human-caused sources of contamination
to be controlled. These sources include
wild animal populations, wastewater
treatment plants, grazing animals,
feedlots, and recreational activities. The
Guidance Manual recommends that
grazing and sewage discharges not be
permitted widiin the watershed of
unfiltered systems, but indicates that
these activities may be permissible on a
case-by-case basis where there is a long
detention time and a high degree of
dilution between the point of activity
and the water intake.
3. Summary of New Data and
Perspectives
Since proposal of the IESWTR in July
1994, several new outbreaks of
waterborne cryptosporidiosis have
occurred in the United States. A recent
summary of these outbreaks (Solo-
Gabriele and Neumeister, 1996)
identified raw sewage, surface runoff
from livestock grazing areas, septic tank
effluent, cattle wastes, treated
wastewater, and backflow of
contaminated water in die distribution
system as the suspected sources of
Cryptosporidium contamination of the
water supplies in these outbreaks. Cattle
grazing, feedstocks and in particular,
calves and other young livestock, appear
to be of greater concern for
Cryptosporidium contamination than for
Giardia. Some outbreaks of
cryptosporidiosis have been related to
upsets in the treatment process of
filtered water systems or have occurred
on occasions when spikes in turbidity
have occurred in those systems.
However, little information is available
for unfiltered water systems as to
whether spikes in raw water turbidity
increase the likelihood that elevated
levels of Cryptosporidium are present in
the source water. Because
Cryptosporidium cannot easily be
controlled with conventional
disinfection practices, there is particular
concern about the presence of this
organism in the source waters of
systems tihat do not filter.
Data from the ICR may be useful in
providing information on the relative
Giardia and Cryptosporidium levels in
die raw water sources of unfiltered and
filtered water systems. In one
comprehensive study on Giardia and
Cryptosporidium densities in ambient
water and drinking water, investigators
(LeChevallier and Norton, 1995) found
Cryptosporidium oocyst levels in
ambient water ranging from 0.065/L to
65.1/L, with a geometric mean of 2.4
oocysts/L. In drinking water, the level of
Cryptosporidium oocysts ranged from
0.29-57 oocysts/lOOL, with a mean of
3.3 oocysts/lOOL.
The Seatde Water Department
summarized the Giardia and
Cryptosporidium monitoring results
from several unfiltered water systems
(Montgomery Watson, 1995). The
central tendency of diis data is about 1
oocyst/lOOL. Thus, depending upon
what removal efficiencies are achieved
by filtration for Cryptosporidium (for
example, 2 logs), it appears that
unfiltered water systems that comply
with the source water requirements of
die SWTR may have a risk of
cryptosporidiosis equivalent to tiiat of a
water system with a well-operated filter
plant using a water source of average
quality.
Although there are no specific
monitoring requirements in the
watershed protection program, the non-
filtering utility is required to develop
state-approved techniques to eliminate
or minimize the impact of identified
point and non-point sources of
pathogenic contamination. USEPA is
considering adding specific monitoring
requirements to the IESWTR for the
unfiltered supplies serving 10,000 or
more people to ensure the continued
effectiveness of the watershed control
program. The monitoring would be
similar to the requirements under the
ICR for Giardia and Cryptosporidium
altiiough the sampling frequency may be
modified. As widi the ICR, a USEPA-
approved method and laboratory for
Giardia and Cryptosporidium analyses
would be required.
At a minimum, such a monitoring
program might require some level of
routine sampling (e.g., on a weekly,
biweekly or monthly basis). The
program may also include "event"
sampling. An "event" would constitute
an occasion when the raw water
turbidity and/or fecal/total coliform
concentration exceeded a specific value
or possibly exceeded a site-specific 90th
percentile value. At least one sample
during an event might be required in
addition to routine sampling. Results of
all protozoa and related analyses would
be made available to the State at a
minimum as part of the annual on-site
inspection required under die SWTR for
non-filtering supplies.
USEPA is continuing to consider
extending the existing watershed
control requirements for unfiltered
systems to include die control of
Cryptosporidium. USEPA requests
further comment on this issue. The
Agency also requests comment on issues
pertaining to monitoring for unfiltered
systems serving 10,000 or more people,
including comment on the following
approaches:
Routine Source Water Giardia and
Cryptosporidium Monitoring:
Option 1. Weekly Giardia and
Cryptosporidium Monitoring
Option 2. Bi-Weekly Giardia and
Cryptosporidium Monitoring
Option 3. Monthly Giardia and
Cryptosporidium Monitoring
The Agency also requests comments on
whether the frequency of monitoring
should depend on system size, e.g.,
should requirements differ for systems
serving between 10-100,000 people
versus those serving more than 100,000
people.
"Event" Source Water Giardia and
Cryptosporidium Monitoring:
Option 1. No event sampling required.
Option 2. Collect sample(s) for
Giardia and Cryptosporidium when
source water turbidity exceeds 1.0 NTU
or some alternative value such as a site-
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specific 90th percentile which might be
lower than 1.0 NTU.
Option 3. Collect sample(s) for
Giardia and Ciyptosportdium when
source water fecal coliform
concentration exceeds 20 per 100 mL or
total coliform level exceeds 100 per 100
mL, depending on which class of
coliforms is used under the individual
systems filtration avoidance agreement.
Alternatively, the trigger could be some
other coliform or fecal coliform value.
Option 4. Individual utility develops
turbidity frequency distribution (e.g.,
based on previous 1 to 3 years of daily
historical data) and collects sample(s)
for Giardia and Cryptosporfdium when
turbidity exceeds 90th percentile level.
Option 5. Some combination of
Options 2, 3, or 4.
The Agency also requests comment on
whether any of the above options
should depend on system size.
G. Sanitary Survey Requirements
1. Summary of 1994 Proposal and
Public Comments
The July 29.1994, Federal Register
proposed to amend the SWTR to require
periodic sanitary surveys for all public
water systems that use surface water, or
ground water under the direct influence
of surface water, regardless of whether
they filter or not. States would be
required to review the results of each
sanitary survey to determine whether
the existing monitoring and treatment
practices for that system are adequate,
and if not, what corrective measures are
needed to provide adequate drinking
water quality.
The July 1994 notice proposed that
only the State or an agent approved by
the State would be able to conduct the
required sanitary survey, except in the
unusual case where a State has not yet
Implemented this requirement, i.e., die
State had neither performed the
required sanitary survey nor generated a
list of approved agents. The proposal
suggested that under exceptional
circumstances the sanitary survey could
be conducted by the public water
system with a report submitted to the
State within 90 days. USEPA also
requested comment on whether sanitary
surveys should be required every three
or every five years.
Most commenters on this issue voiced
support for requiring a periodic sanitary
survey for all systems. One commenter
suggested that USEPA develop sanitary
survey guidance for administration by
the States, while anotiher commenter
suggested that sanitary surveys by the
private sector be certified by States or
national associations using USEPA-
defined criteria. Commenters
recommended that surveys be
conducted either by the State or a
private independent parly/contractor.
One respondent contended that sanitary
surveys, as presently conducted, were
insufficient to assess operational
effectiveness in surface water systems.
With regard to sanitary survey
frequency, commenters were nearly
evenly divided between every three
years and every five years. Some
commenters argued that the frequency
should depend on: (1) whether a
system's control is effective or marginal,
(2) system size (less frequent for small
systems), (3) source water quality, (4)
whether the State believes a system's
water quality is likely to change over
time, (5) results of the previous survey,
and (6) population density on the
watershed. One commenter suggested
an annual sanitary survey.
Regarding criteria for sanitary survey
inspectors, some commenters suggested
that die State should decide what
requirements to use. Others suggested
some combination of education and
working experience related to water
plant operations, including (1)
professional engineering certificate and
water plant operator license for at least
five years, (2) knowledge of surface
water contaminants, source and fate of
contaminants, and both removal
capabilities of existing treatment
technologies and ability to evaluate
their performance, (3) a BS degree
(preferably MS degree) in sanitary or
environmental engineering with two
years experience in evaluating water
treatment plants and valid plant
operator's license, (4) five years
experience in water system operation,
evaluation, and/or design, and a BS in
engineering or environmental science,
(5) a BS degree in science or engineering
and five years experience in the
drinking water field.
2. Overview of Existing Regulations and
Guidance
Sanitary surveys have historically
been conducted by state drinking water
programs as a preventive tool to identify
water system deficiencies that could
pose a threat to public health. The first
regulatory requirement for systems to
have a periodic on-site sanitary survey
appeared in the final TCR (54 FR
27544-27568). This rule requires all
systems that collect less than 5 total
coliform samples each month to
undergo such surveys. These sanitary
surveys must be conducted by the State
or an agent approved by the State.
Community water systems were to have
had the first sanitary survey conducted
by June 29, 1994, and every five years
thereafter while non-community water
systems are to have the first sanitary
survey conducted by June 29, 1999, and
every five years thereafter unless the
system is served by a protected and
disinfected ground water supply, in
which case, a survey must be conducted
every 10 years.
The SWTR did not specifically
require water systems to undergo a
sanitary survey. Instead, it required that
unfiltered water systems, as one
criterion to remain unfiltered, have an
annual on-site inspection to assess the
system's watershed control program and
disinfection treatment process. The on-
site survey must be conducted by the
State or a party approved by the state.
This on-site survey is not a substitute
for a more comprehensive sanitary
survey, but the information can be used
to supplement a full sanitary survey.
USEPA's SWTR Guidance Manual
(USEPA, 199la), Appendix K, suggests
that, in addition to the annual on-site
inspection, a sanitary survey be
conducted every three to five years by
both filtered and unfiltered systems.
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."
3. New Developments
Since the publication of the proposed
ESWTR in 1994. USEPA and the States
(through the Association of State
Drinking Water Authorities), have issued
a joint guidance on sanitary surveys
entitied USEPA/State Joint Guidance on
Sanitary Surveys (1995), The Guidance
outlines the following elements as
integral components of a comprehensive
sanitary survey:
• Source
—Protection
—Physical Components and
Condition
• Treatment
• Distribution System
• Finished Water Storage
• Pumps/Pump Facilities and Controls
• Monitoring/Reporting/Data
Verification
• Water System Management/
Operations
• Operator Compliance with State
Requirements
The guidance also addresses the
qualifications for sanitary survey
inspectors, the development of
assessment criteria, documentation,
follow-up after the survey, tracking and
enforcement.
USEPA is aware that a number of
States have independently developed
their own sanitary survey criteria. For
instance, the American Water Works
Association California-Nevada Section,
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Source Water Quality Committee in
conjunction with the California
Department of Health Services, Division
of Drinking Water and Environmental
Management (DHS) have published a
document entitled Watershed Sanitary
Survey Guidance Manual (AWWA
California -Nevada Section 1993) to
assist domestic water suppliers in
defining the scope of their watershed
sanitary surveys and to provide
information on the methods and sources
of information for conducting sanitary
surveys.
4. Advisory Committee
Recommendations and Related Issues
USEPA reiterates its request for
comment on the following
recommendations of the M-DBP
Advisory Committee.
A sanitary survey would be defined as an
onsite review of the water source (identifying
sources of contamination using results of
source water assessments where available).
facilities, equipment, operation,
maintenance, and monitoring compliance of
a system to evaluate the adequacy of the
system, its sources and operations and the
distribution of safe drinking water. Included
in this definition is the concept that
components of a sanitary survey may be
completed as part of a staged or phased State
review process within the established
frequency interval set forth below. Finally,
for a sanitary survey to fall within this
definition, it must address each of the eight
elements in the December 1995 USEPA/State
Guidance on Sanitary Surveys.
In terms of frequency, this approach would
provide that sanitary surveys must be
conducted for all surface water systems
(including ground water under the influence)
no less frequently than every three years for
community systems and no less frequently
than eveiy five years for noncommunity
systems. Any sanitary survey conducted after
December 1995, that addresses the eight
sanitary survey components of the 1995 EPA/
State guidance, may be counted or
"grandfathered" for purposes of completing
the round of surveys. This approach would
also provide that for community systems
determined by the State to have outstanding
performance based on prior sanitary surveys.
successive sanitary surveys may be
conducted no less than every five years.
Finally, under this approach, as part of
follow-up activity for sanitary surveys,
systems must respond to deficiencies
outlined in the State's sanitary survey report
within 45 days, indicating how and on what
schedule the system will address significant
deficiencies noted in the survey. In addition.
States must have the appropriate rules or
other authority to assure that facilities take
the steps necessary to address significant
deficiencies identified in the survey report
that are within the control of the PWS and
its governing body.
USEPA also requests comment on
whether systems should be required to
respond in writing to a State's sanitary
survey report discussed in the
paragraph above. USEPA also requests
comment on (1) what would constitute
"outstanding performance" for purposes
of allowing sanitary surveys for a
community water system to be
conducted every five years and (2) how
to define "significant deficiencies."
H. Covered Finished Water Reservoirs
1. Summary of the 1994 Proposal and
Public Comments Received
The July 29, 1994. Federal Register
indicated that USEPA was considering
whether to issue regulations requiring
systems to cover finished water
reservoirs and storage tanks, and
requested public comment. The
rationale for this position was given in
the proposed rule.
Most commenters supported either
federal or State requirements. Some
commenters suggested that regulations
apply only to new reservoirs. Some
commenters opposed any requirement,
citing high cost, the notion that "one
size does not fit all", and aesthetic
benefits of an open reservoir.
Some commenters suggested elements
for such regulations or guidance,
including (1) applying the same criteria
to finished water reservoirs as exists for
unfiltered surface water systems, (2)
using engineering measures to minimize
contamination, (3) disinfecting the
effluent to maintain residual in
distribution system, (4) monitoring
reservoirs routinely for water quality
indicators, (5) covering all storage tanks,
(6) fencing reservoirs with signs
warning against swimming, trespassing,
and tampering, and (7) adding notices in
the annual water quality report that the
reservoir is not in compliance with
current waterworks standards. A few
commenters suggested a number of
other elements.
2. Overview of Existing Information
Possible Health Concerns: When a
finished water reservoir is open to the
atmosphere it may be subject to some of
the environmental factors that surface
water is subject to, depending upon site-
specific characteristics and the extent of
protection provided. It may be subject to
contamination by persons tossing items
into the reservoir or illegal swimming
(Pluntze 1974; Erb, 1989).
Microscopic and other organisms may
proliferate in open finished water
reservoirs. Increases in algal cells,
heterotrophic plate count (HPC)
bacteria, turbidity, color, particle
counts, biomass and decreases in
chlorine residuals have been reported
(Pluntze, 1974, AWWA Committee
Report, 1983, Silvermanet al., 1983,
LeChevallier et al. 1997a).
Small mammals, birds, fish, and the
growth of algae may contribute to the
microbial degradation of an open
finished water reservoir (Graczyk et al.,
1996; Geldreich, 1990; Payer and Ungar,
1986; Current, 1986). Mammals, birds
and fish and their carcasses seed the
water and the sediment with total and
fecal coliforms, E. coli and pathogens. In
one study, sea gulls contaminated a 10
million gallon reservoir and increased
bacteriological growth and in another
study waterfowl were found to elevate
coliform levels in small recreational
lakes by twenty times their normal
levels (Morra, 1979). Seagulls are a
source of numerous coliforms and can
also be a source for several human
pathogens, (Geldreich and Shaw, 1993).
Algal growth increases the biomass in
the reservoir, which reduces dissolved
oxygen and thereby increases the release
of iron, manganese, and nutrients from
the sediments. This, in turn, supports
more growth (Cooke and Carlson, 1989).
Plants, macrophytes and organic debris
will add to the biomass and nutrient
supply.
State Regulations: In order to assess
regulatory requirements at the State
level, it is necessary to contact
individual drinking water programs and
collect and evaluate specific regulatory
language obtained from those programs.
A survey of nine States was conducted
in the summer of 1996 (Montgomery
Watson, 1996). The States which were
surveyed included several in the West
(Oregon, Washington, California, Idaho,
Arizona, and Utah), two States in the
East known to have water systems with
open reservoirs (New York and New
Jersey), and one midwestern state
(Wisconsin). Seven of the nine States
which were surveyed require by direct
rule that all new finished water
reservoirs and tanks be covered.
Survey of Ten Utilities: There is no
comprehensive information available on
the number or size of open finished
water reservoirs in water systems
around the country; however, there is
one recent survey of ten utilities which
either have open finished water
reservoirs or which had them in the past
and covered or replaced them (E&S
Environmental Chemistry, 1997). The
existing open reservoirs which were
operated by these systems varied greatly
in size, from 5.5 million gallons (MG) to
900 MG. The systems with open
finished reservoirs also had closed
reservoirs within their service area, but
for some of the systems the open
reservoirs represent the largest
component of total storage volume in
the systems.' • -'•'..4-~-
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59510 Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules
Most of the reservoirs in the systems
in this survey were excavated and lined,
but several of the larger ones were
formed by dams or natural lakes that
had been converted to water supply use.
Many of these reservoirs have irregular
geometry and configurations which
make covering very difficult or
impossible. Others are so large that
covering them would be impractical.
For some of these reservoirs, it is
impractical to find locations for
replacement with the proper hydraulic
characteristics and size. To partially
solve this problem in some cases,
systems have chosen to leave large
existing open reservoirs off-line, except
for emergency supply purposes.
None of the systems had
comprehensive evidence about the
effect of open reservoirs on water
quality. These water systems had
instituted a number of measures at open
reservoirs to control potential sources of
contamination; these measures included
fencing setbacks, security cameras, on-
site surveillance, rechlorination, wire
canopies to control bird activity, and
other measures.
3. Request for Public Comment
USEPA is considering as part of the
1ESWTR a requirement that systems
cover all new reservoirs, holding tanks
or other storage facilities for finished
water for which construction begins
after the effective date of the rule. The
Agency intends to further consider this
issue, including whether there should
be a requirement that all finished water
reservoirs, holding tanks and other
storage facilities be covered, as part of
the development of the Long-Term
ESWTR. The Agency requests further
comment on this issue and whether
provisions should be established to
require all new reservoirs, holding
tanks, or other storage facilities to be
covered.
/. Cross Connection Control Program
I, Summary of 1994 Proposal and
Public Comments
The July 29.1994, Federal Register
requested public comment on whether
the Agency should require States and/or
systems to have a cross-connection
control program. In addition, the
Agency solicited comment on a number
of associated issues, including (1) what
specific criteria, if any, should be
included in such a requirement, (2) how
often such a program should be
evaluated, (3) whether USEPA should
limit any requirement to only those
connections identified as a cross'
connection by the public water system
or the State, and (4) conditions under
which a waiver from this requirement
would be appropriate. The Agency also
requested commenters to identify other
regulatory measures USEPA should
consider to prevent contamination of
drinking water in the distribution
system (e.g., minimum pressure
requirements in the distribution
system).
Most commenters supported either a
federal or State cross connection control
program. Various commenters
recommended that such a program
include a backflow prevention program
with approved backflow preventer lists,
categorization of all service connections
with respect to potential risk of
backflow, requirement for periodic
testing and maintenance of backflow
prevention devices, periodic review of
program by State, establishment of an
annual backflow device testing program,
establishment of a backflow device
inspector certification program,
enforcement authority, and other
suggestions. Commenters also
recommended national disinfection
procedures for repair of water lines and
for placing new lines into service, a
provision for at least one person trained
in cross-connection control to cany out
the program, and other suggestions.
Commenters opposed to a cross
connection control program indicated
that (1) a federally-mandated program
would be impractical, burdensome, and
would fail, (2) a State program would be
more appropriate than an USEPA-
mandated program, (3) most States
already have a comprehensive program,
thus negating need for federal
regulations, (4) USEPA should publish
general guidelines only, and (5) there
should be a separate regulation because
a cross connection control program
would affect both surface water and
ground water.
2. Overview of Existing Information
Historically, a significant portion of
waterborne disease outbreaks reported
by CDC are caused by distribution
system deficiencies. Distribution system
deficiencies are defined in CDC's
publication Morbidity and Mortality
Weekly Report as cross connections,
contamination of water mains during
construction or repair, and
contamination of a storage facility.
Between 1971-1994, approximately 53
waterborne disease outbreaks were
associated with cross connections or
backsiphonage. Fifty-six outbreaks were
associated with other distribution
system deficiencies (Craun, Pers. Comm.
1997b). Some outbreaks have resulted
from water main breaks or repairs.
There is no centralized repository
where backflow incidents are reported
or recorded. The vast majority of
backflow incidents are probably not
reported. Specific backflow incidents
are described in detail in USEPA's
Cross-Connection Control Manual
(USEPA, 1989a).
Where cross connections exist, some
protection is still afforded to the
distribution system by the maintenance
of a positive water pressure in the
system. Adequate maintenance of
pressure provides a net movement of
water out through breaks in the
distribution pipes and prevents
contaminated water outside of the pipes
from entering the drinking water
supply. The loss of pressure in the
distribution system, less than 20 psi,
can cause a net movement of water from
outside the pipe to the inside, possibly
allowing the introduction of fecal
contamination into the system. This
problem is of special concern where
wastewater piping is laid in the same
street as the water pipes, creating a
potential threat to public health
whenever there is low or no pressure.
Many States have cross connection
control programs. A Florida Department
of Environmental Protection survey
evaluated cross-connection control
regulations in the 50 states (Florida DEP
1996). The survey results showed that
29 of the 40 states that responded to the
survey request have programs. The rigor
of the programs and the extent to which
they are enforced was not addressed by
the survey. An USEPA report suggests
that the responsibility for
administration and enforcement of the
State programs is generally at the local
level (USEPA, 1995a). .
3. Request for Public Comment
USEPA does not plan to address cross
connection control in the IESWTR. As
noted above, many States currently have
programs, although the extent to which
these vary is unclear. The Agency does
plan to consider cross connection
control issues during the development
of the Long-Term ESWTR, in the context
of a broad range of issues related to
distribution systems. USEPA continues
to request comments or additional
information related to cross connection
control or other distribution system
issues.
J. Recycling Filter Backwash Water and
Filtering to Waste
The July 29, 1994, notice requested
comment on the extent to which the
ESWTR should address the issue of
recycling filter backwash water, given
its potential for increasing the densities
of Giardia and Cryptosporidium on the
filters. The 1996 Amendments to the
SOW A require USEPA to promulgate a
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Federal Register / Vol. 62. No. 212 / Monday November 3, 1997 / Proposed Rules 59511
regulation for filter backwash recycling
not later than August 2000, (SDWA
14120b)(14)).
Most commenters who addressed this
issue contended that backwash water
should not be recycled or that, if it is
recycled, it should be treated first. One
commenter suggested that this decision
should be based on the pathogen
density in the backwash water. Another
commenter suggested that the rule
should include criteria for assessing the
extent of backwash recycling,
depending on raw water quality, size of
filters, and water volume. Another
commenter maintained that this issue
should be left to the State and system.
One commenter suggested that the
impacts of recycling needed additional
research and that any rule addressing
this issue needed to incorporate the
results of die latest research.
1. Filter Backwash Recycle
Configurations
Treatment plants can be configured
into several general categories but the
variation within each category is
significant.
One aspect of this treatment variation
is how recycling of waste streams from
plant .processes are handled. Figure 4
shows a general schematic of a
conventional treatment plant and how
recycle streams may be developed and
treated. Note that backwash water
treatment is carried out in a miniature
coagulation-flocculation-sedimentation
treatment facility. Some utilities are
considering microfiltration to replace
these unit processes.
BILLING CODE 6560-50-P
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CI2
River
Sludge from
Backwash
Treatment
•Alum •
Lime
Polymer
Fluoride
Corrosion Inhibitor
Figure 4. Schematic of Typical Waste Stream Recycle with Treatment
KUJHQ CODE BSW-60-C
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59513
Figure 5 shows an alternate view for
some water treatment facilities that do
not practice treatment of their recycled
waste streams. There is an almost
infinite variety between these two
examples. In addition, waste streams
can be recycled to many different points
in the treatment train. The most
common recycle points are at the plant
influent or rapid mix. However, there
are several known examples of recycle
streams being introduced into the
treatment process as late as the filter
influent.
BILLING CODE 6560-50-P
Figure 5. Schematic of Typical Waste Stream Recycle without Treatment
River
Untreated
Backwa«h Water
Sludge to
Sewer
Backwash Water
Fluoride, Corrosion Inhibitor
BILLING CODE 6560-50-C
Figure 6 shows a typical plot of
turbidity over time from a filter from
reintroduction into service after
backwash to breakthrough of turbidity at
the end of the filter run. Some plants
have installed filter-to-waste facilities
which allow the discharge of the first
minutes of a filter's operation after
backwashing usually into the backwash
reclamation system. In California, the
State drinking water regulations define
filter-to-waste as: ' "Filter-to-waste"
means a provision in a filtration process
to allow the first filtered water, after
backwashing a filter, to be wasted or
reclaimed.' (McGuire, 1994)
BILLING CODE 6560-50-P
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0.5
TO
.a
Filter
Ripening
S pike
T u rb id ity
B re a kth ro u g h
24
Hours
Figure 6. Plot of Turbidity Profile
OIUJNQ CODE 6550-50-C
Figure 7 shows a general schematic of
a Illter-to-waste operation. After the
backwash process is complete and the
filter influent water is allowed to enter
the filter, Valve A is operated so that all
of the filter effluent water is sent to
waste. After a specified period of time
or when it is determined that the
ripening spike is largely over. Valve A
is operated so that the filtered water
becomes part of the product water of the
treatment plant.
BILLING CODE 6560-50-P
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Figure 7. Filter-to-Waste Operation
-r-
Filter
Influent
u
Valve
A
<^->
1
F
}
Filtered
Water
To
Waste
BILLING CODE 6560-50-C
2. State Drinking Water Regulations
California has specific regulations that
deal with backwash recycle and filter-
to-waste. Treatment of backwash recycle
flows is covered in the design of
treatment facilities section. For new
construction, utilities are required to
install solids removal treatment for
recycled filter backwash water. Also,
treated backwash water must be
returned to the "headworks" (i.e., the
plant influent) of the treatment plant.
Solids removal treatment unit processes
are not specified in the regulation, but
new construction must be' approved by
the California Department of Health
Services (California Health and Safety
Code, Sections 646658 & 64660).
To minimize the filter ripening spike,
the California Department of Health
specifies operational requirements such
that filtration rates are increased
gradually when filters are placed back
into service following backwashing or
any other interruption in the operation
of the filter. When any individual filter
is placed back into service following
backwashing or other interruption
event, the filtered water turbidity from
that filter cannot exceed any of the
following criteria:
• 2.0 NTU.
• 1.0 NTU in at least 90 percent of the
interruption events during any
consecutive 12-month period.
• 0.5 NTU after the filter has been in
operation for 4 hours.
For new construction, utilities are
required to provide filter-to-waste or
add additional coagulant chemicals to
backwash water.
3. Literature Overview of Standard of
Practice
a. Treatment Reference Texts. The
joint ASCE/AWWA (1990) water
treatment plant design book includes
one section on page 182 dealing with
washwater disposal and recovery. The
section lists several possibilities
including recycling without treatment,
equalization and treatment, and lagoons
to provide for both equalization and
sedimentation. On page 188, the
backwash recycle facility at the Duluth,
Minnesota plant is described. Chemical
addition, flocculation and clarification
comprise the backwash treatment
system.
The fourth edition of Water Quality
and Treatment contains one section on
pages 988-989 dealing with filter
backwash residuals. The section notes
that recovery of "dirty" backwash water
is becoming increasingly common and
that the volume of backwash water is
typically one to five percent of total
plant production. Flow equalization is
listed as the most common approach to
dealing with recycling of backwash
water. The section states that "For
conventional plants, solid separation
before return is not common, and some
holding tanks are mixed to keep solids
in suspension." Direct filtration plants
are noted for needing solids separation
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59516 Federal Register / Vol. 62. No. 212 / Monday November 3, 1997 / Proposed Rules
treatment of backwash water, because
there Is no sedimentation facility in a
direct filtration plant. Concerns are
expressed in the section about
increasing the concentrations of Giardia
cysts in the plant influent with the
recycle of untreated backwash water.
A handbook of practice was published
in 1987 dealing with water treatment
plant waste management. Backwash
water was described as a major waste
stream on page 5 and flow equalization
was listed as an important requirement.
The handbook gives specific examples
of the size of backwash basins needed
based on the number of filters
backwashed and the backwash
frequency. The example discusses
tankage volumes that would allow a
maximum 10 percent recycle rate of the
backwash water to the plant influent.
Neither clarification nor polymer
addition were mentioned in this early
reference (Cornwell et al., 1987).
b. ICR Treatment Plants. Of the 523
treatment plants subject to the ICR, 282
use conventional treatment. Of the
conventional treatment plants, 146 (or
52%) practice recycling of their
backwash water. Additionally, 15 direct
filtration plants and 3 in-line filter
plants recycle their backwash water.
These data show that a large fraction of
the surface water treatment plants
recycle their backwash water.
the ICR will provide the first detailed
data on the number of treatment plants
that treat their recycled backwash water
and the technologies they use and some
limited data on backwash water quality.
Until the initial sampling plan data is
available for analysis sometime in early
1998, the only information available on
the ICR utilities is from their Initial
Sampling Schematics and that will only
show the addition of a treatment
chemical. The Initial Sampling
Schematics do not indicate if
coagulation, flocculation or
sedimentation is used for washwater
recycle treatment.
An inspection of those schematics
revealed the following information on
treatment of recycled backwash water. A
total of 164 schematics for plants using
conventional treatment, direct filtration
or in-line filtration were examined.
Only 12 of the plants indicated that they
provided any chemical treatment.
Addition of a polymer was practiced at
5 plants. Chlorination as the only
treatment of the recycled washwater
was found at 2 plants. A total of 5 plants
provided both chlorination and polymer
treatment of the backwash water.
c. Comwell and Lee 1993 Report.
Another source of information on waste
stream quality and the impact of
recycling of these streams on treated
water quality is found in an American
Water Works Association Research
Foundation (AWWARF) 1993 report
authored by Cornwell and Lee. They
studied the quality characteristics of
waste streams from 24 treatment plants
and investigated the treatment
characteristics in some detail at 8
plants.
Among the contaminants analyzed
were Giardia and Cryptosporidium. The
study found that filter backwash water
could have very high cyst/oocyst
concentrations and chemical loads.
However, the researchers found no
finished water quality problems as a
result of recycling.
The study found that backwash water
sedimentation was effective in reducing
particle and pathogen concentrations in
the used filter backwash water.
However, very low overflow rates (less
than 0.05 gpm/sf) of the sedimentation
basin were required to achieve the
solids removal unless a polymer was
used. Using an anionic polymer
increased the particle removals and
allowed sedimentation overflow rates of
0.2 to 0.3 gpm/sf. The last two sentences
of the Executive Summary of the report
provide insight into the overall findings.
"The use of equalized, continuous recycle,
proper waste stream treatment prior to
recycle, and characterization of waste stream
quality through proper monitoring should be
used In conjunction with recycle operations.
If these recommendations are used, recycle
can be an appropriate part of water treatment
operations (Cornwell and Lee, 1993)."
In a paper which summarized the
report findings, the authors stated a
general rule that the recycle streams
should be flow equalized and blended
in to the plant flow over the entire 24
hour plant operating cycle. The rule of
thumb that the amount of recycle
should be less than 10 percent of the
plant flow may not be sufficient, and a
lower percentage of recycle may have to
be practiced depending on the quality of
the recycled water (Cornwell and Lee,
1994).
d. Other Studies. In 1996, AWWA
conducted a survey of treatment plants
to determine the extent of backwash
water recycling and the treatment
provided to that water (McGuire, 1997).
A total of 400 plants from utilities
serving more than 100,000 people were
contacted. About 40 percent of those
plants responded. Of those responding,
about 60 percent of the plants recycled
their filter backwash water. The other 40
percent appeared to discharge the
backwash water to a surface water
supply or to a sanitary sewer. Of the
plants that recycled their backwash
water, 27 percent responded that they
treated the recycle water. The important
point to note from this limited survey is
that recycle of backwash water appears
to be a common practice among water
treatment plants.
4. Filter-to-Waste
One possible concern is the discharge
of large number of particles from filters
that are put back into service after
backwashing. Work done on Giardia
removal by filtration at Fort Collins,
Colorado, indicated that a filter-to-waste
period was not necessary to produce
low Giardia filter effluent levels as long
as proper chemical preconditioning of
the filter was practiced (Gertig et al.
1988). Logsdon et al. studied
sedimentation and several different
filter media from removing Giardia cysts
at McKeesport, Pennsylvania. Giardia
cyst concentrations were found to be
higher at the beginning of the filter run,
indicating that filter-to-waste may be
needed to reduce the levels of Giardia
in the finished water (Logsdon et al,
1985).
One study (Amirtharajah, 1988)
indicated that more than 90% of the
particles that pass through a filter do so
during the initial stages of filtration.
Another study (Logsdon etal., 1981)
found that initial cyst concentrations in
the effluent, after backwash, were from
10 to 25 times higher than those in the
stabilized filter run, even though the
difference in turbidity was less than 0.1
NTU. One British study (Hall and Croll
1996) found that in one test filter run,
calculation of the total number of
particles released during the whole run
showed that up to 30% of the particles
were released during the first hour of
filter ripening. The turbidity during this
peak was 0.4 NTU. Gradual start of the
filter after backwashing reduced the
peak particle count in the effluent.
Effectiveness of practicing filter-to-
waste in reducing the passing of oocysts
depends on the duration of the ripening
period. For example, a 15 minute filter-
to-waste period will not be very
effective for a ripening period of 2
hours. Mid and end-of-run turbidity
spikes can also pass large number of
particles (including pathogen oocysts)
into the effluent. However, these latter
spikes can be controlled by avoidance of
flow changes and by timely
backwashing the filter.
5. Request for Public Comment
USEPA does not plan to include
separate provisions for recycling of filter
backwash water and filter-to-waste
issues in the IESWTR. The Agency
anticipates that some systems will
address these issues as part of their
efforts to comply with revised turbidity
performance standards of 0.3 NTU for
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Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules 59517
the 95th percentile of monthly
measurements and a maximum turbidity
level of 1 NTU. As previously discussed
in this Notice, USEPA is required under
the 1996 Amendments to the SDWA to
issue a regulation to address filter
backwash recycling by August 2000.
USEPA plans to develop these
regulations in conjunction with the
development of the Long-Term ESWTR.
USEPA continues to request comments
or additional information related to
recycling of filter backwash water or
filter-to-waste issues.
K. Certification Criteria for Water Plant
Operators
The July 29,1994, notice requested
comment on whether the ESWTR
should define minimum certification
criteria for surface water treatment plant
operators. Currently, the SWTR (141.70)
requires such systems to be operated by
"qualified personnel who meet the
requirements specified by the State."
The 1996 Amendments to the SDWA
require USEPA to undertake several
actions with regard to operator
certification, including the publication
of guidelines specifying minimum
standards.
Of the few commenters who
addressed this issue most asserted that
minimum certification criteria for water
operators should be left to the States.
One commenter contended that certified
operators) should be on site at all times
and that a non-certified operator should
never be in charge. Another respondent
noted that rewording § 141.70 to read
"personnel who are certified by the
State, or can obtain certification within
one year of date of employment" will
adequately define certification criteria.
Consistent with the 1996 SDWA
amendments, USEPA appointed an
Operator Certification Working Group of
the National Drinking Water Advisory
Council (NDWAC) to form a partnership
with States, water systems and the
public to develop information on
recommended operator certification
requirements. USEPA will publish
guidelines specifying minimum
standards for certification (and
recertification) of operators of
community and nontransient
noncommunity public water systems.
USEPA is developing the draft
guidelines based on recommendations
from the NDWAC. The draft guidelines,
when available, will be published in the
Federal Register for public review and
comment. Members of the public who
are interested in further information
regarding this effort may contact
Richard Naylor of USEPA's Office of
Ground Water and Drinking Water at
202-260-5135 or at e-mail address:
naylor.richard@epamail.epa.gov.
L. Regulatory Compliance Schedule and
Other Compliance-Related Issues
A. Regulatory Compliance Schedule
Background
During the 1992 Disinfectants/
Disinfection Byproducts Regulatory
Negotiation (reg-neg) that resulted in the
1994 proposed Stage 1 DBPR and
proposed IESWTR, there was extensive
discussion of the compliance schedule
and applicability to different groups of
systems and coordination of timing with
other regulations.
In addition to the Stage 1 DBPR, the
Negotiating Committee agreed that EPA
would (a) propose an interim ESWTR
which would apply to surface water
systems serving 10,000 or more people,
and (b) at a later date, propose a long-
term ESWTR applying primarily to
small systems under 10,000. Both of
these microbial rules would be
proposed and promulgated so as to be
in effect at the same time that systems
of the respective size categories would
be required to comply with new
regulations for disinfectants and DBPs.
Finally, although the GWDR was not
specifically addressed during the reg-
neg, EPA anticipated that it would be
promulgated at about the same time as
the IESWTR and Stage 1 DBPR.
EPA proposed a staggered compliance
schedule, based on the reg-neg results.
The Negotiating Committee and EPA
believed that such a process was needed
for the rules to be properly implemented
by both States and PWSs. Also, EPA
proposed a staggered schedule to
achieve the greatest risk reduction by
providing that larger water systems were
to come into compliance earlier than
small systems (to cover more people
earlier), and surface water systems were
to come into compliance earlier than
ground water systems (since the
potential risks of botfi pathogens and
DBPs were considered generally higher
for surface water systems). Large and
medium size surface water PWSs
(serving at least 10,000 people)
constitute less than 25% of community
water systems using surface water and
less than 3% of the total number of
community water systems, but serve
90% of the population using surface
water and over 60% of the population
using water from community water
systems. These large PWSs are also
those with experience in simultaneous
control of DBPs and microbial
contaminants. EPA proposed that these
systems be required to comply with the
Stage 1 DBPR and IESWTR 18 months
after promulgation of the rules and that
States would be required to adopt the
rules no later than 18 months after
promulgation. These 18 month periods
were prescribed in the 1986 SDWA
Amendments.
Surface water PWSs serving fewer
than 10,000 people were to comply with
the Stage 1 DBPR requirements 42
months after promulgation, to allow
such systems to simultaneously come
into compliance with the LTESWTR.
This compliance date reflected a
schedule that called for the LTESWTR
to be promulgated 24 months after the
IESWTR was promulgated and for PWSs
then to have 18 months to come into
compliance. Such a simultaneous
compliance schedule was intended to
provide the necessary protection from
any downside microbial risk that might
otherwise result when systems of this
size attempted to achieve compliance
with the Stage 1 DBPR.
Ground water PWSs serving at least
10,000 people would also be required to
achieve compliance with the Stage 1
DBPR 42 months after promulgation. A
number of these systems, due to
recently installing or upgrading to meet
the GWDR (which EPA planned to
promulgate at about the same time as
the Stage 1 DBPR), were expected to
need some period of monitoring for
DBPs in order to adjust their treatment
processes to also meet the Stage 1 DBPR
standards.
1996 Safe Drinking Water Act
Amendments
The SDWA 1996 Amendments
affirmed several key principles
underlying the M-DBP compliance
strategy developed by EPA and
stakeholders as part of the 1992
Regulatory Negotiation process. First,
under Section 1412(b)(5)(A), Congress
recognized the critical importance of
addressing risk/risk tradeoffs in
establishing drinking water standards
and gave EPA the authority to take such
risks into consideration in setting MCL
or treatment technique requirements.
Second, Congress explicitly adopted the
staggered M-DBP regulatory
development schedule developed by the
Negotiating Committee. Section
1412(b)(2)(C) requires that the standard
setting intervals laid out in EPA's
proposed ICR rule be maintained even
if promulgation of one of the M-DBP
rules was delayed. As noted above, this
staggered regulatory schedule was
specifically designed as a tool to
minimize risk/risk tradeoff. A central
component of this approach was the
concept of "simultaneous compliance"
which provides that a PWS must
comply with new microbial and DBF
requirements at die same time to assure
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59518 Federal Register / Vol. 62. No. 212 / Monday November 3, 1997 / Proposed Rules
that In meeting a set of new
requirements In one area, a facility does
not Inadvertently increase the risk (i.e.,
the risk "tradeoff1) in the other area.
The SDWA 1996 Amendments also
changed two statutory provisions that
elements of the 1992 Negotiated
Rulemaking Agreement were based
upon. As outlined above, the 1994 Stage
1 DBPR and ICR proposals provided that
18 months after promulgation large
PWSs would comply with the rules and
States would adopt and implement the
new requirements. Section 1412(b)(10)
of the SDWA as amended now provides
that drinking water rules shall become
effective 36 months after promulgation
(unless the Administrator determines
that an earlier time is practicable or that
additional time for capital
improvements is necessary—up to two
years). In addition, Section 1413(a)(l)
now provides that States have 24
instead of the previous 18 months to
adopt new drinking water standards that
have been promulgated by EPA.
Discussion
In light of the 1996 SDWA
amendments, developing a compliance
deadline strategy that encompasses both
the Stage 1 DBPR and IESWTR, as well
the related LTESWTR and Stage 2
DBPR, is a complex challenge. On the
one hand, such a strategy needs to
reflect new statutory provisions. On the
other, it needs to continue to embody
key reg-neg principles reflected in both
the 1994 ICR and Stage 1 DBPR
proposals; principles that both
Congressional intent and the structure
of the new Amendments, themselves,
indicate must be maintained.
An example of the complexity that
must be addressed is the relationship
between the principles of risk/risk
tradeoff, simultaneous compliance, and
the staggered regulatory schedule
adopted by Congress. Under the 1996
SDWA amendments, the staggered
regulatory deadlines under Section
1412(b)(2)(C) call for the IESWTR and
Stage 1 DBPR to be promulgated in
November 1998 and the LTESWTR in
November of 2000. However, a
complicating factor reflected in the
Negotiated Rulemaking Agreement of
1992 and contained in the 1994 ICR,
IESWTR, and Stage 1 DBPR proposals,
Is that Stage 1 applies to all PWSs,
while IESWTR applies only to PWSs
over 10,000. and the LTESWTR covers
remaining surface water systems under
10.000.
One approach might be to simply
provide that each M-DBP rule becomes
effective 3 years after promulgation in
accordance with the new SDWA
provisions. For surface water systems
over 10,000, each plant would be
required to comply with related
microbial and DBF requirements at the
same time thereby minimizing potential
risk/risk tradeoffs. For surface water
systems under 10,000, however, this
approach would result in a very large
number of smaller plants complying
with DBF requirements two years before
related LTESWTR microbial provisions
became effective, thereby creating an
unbalanced risk tradeoff situation that
the Negotiating Committee, EPA, and
Congress each sought to avoid.
As this example suggests, given the
staggered regulatory development
schedule developed by stakeholders in
the reg-neg process and adopted by
Congress, there is a difficult
inconsistency between the principle of
avoiding risk tradeoffs, simultaneous
compliance, and simply requiring all
facilities to comply with applicable
M-DBP rules three years after their
respective promulgation. The challenge,
then, is to give the greatest possible
meaning to each of the new SDWA
provisions while adhering to the
fundamental principles also endorsed
by Congress of addressing risk-risk
tradeoffs and assuring simultaneous
compliance.
A further question that must be
factored into this complex matrix is how
to address the relationship between
promulgation of a particular rule, its
effective date, and its adoption by a
primacy State responsible for
implementing the Safe Drinking Water
Act. Under the 1994 IESWTR and Stage
1 DBPR proposals, the rule's 18 month
effective date was the same as the 18
month date by which a State was
required to adopt it. This approach
reflected the 18 month SDWA deadlines
applicable during reg-neg negotiations
and at the time of proposal.
The difficulty with requiring PWS
compliance and State implementation
by the same date is that States may not
have enough lead time to adopt rules,
train their own staff, and develop
policies to implement and enforce new
rules by the deadline for PWS
compliance. In situations where the new
rules are complex and compliance
requires state review and ongoing
interaction with PWSs, successful
implementation can be very difficult,
particularly for States with many small
systems that have smaller staffs and
fewer resources to anticipate the
requirements of final rules. As noted
above, Congress addressed this issue by
extending the time for States to put their
own rules in place from 18 months to
two years after federal promulgation
and, then, by generally providing for a
one year interval before PWSs must
comply (three years after promulgation).
As a result, the 18 month interval
contemplated by the 1994 proposals is
no longer applicable, and the approach
of setting the same date for PWS
compliance and State rule
implementation is no longer consistent
with the phased approach laid out in
the new SDWA amendments.
A final set of issues that must be
addressed in connection with the Stage
1 DBPR proposal are compliance
deadlines for ground water systems that
currently disinfect. Reflecting the
Negotiated Rulemaking Agreement, the
1994 proposal provided that ground
water systems serving at least 10,000
that disinfect must comply three and
one half years (42 months) after Stage 1
DBPR promulgation. Small ground
water systems serving fewer than 10,000
that disinfect would be required to come
into compliance five years (60 months)
after Stage 1 DBPR promulgation. Again,
the challenge here is to reconcile new
statutory compliance provisions with
the principles of simultaneous
compliance, avoiding risk/risk tradeoffs,
and deference to Congress' clear intent
to preserve the "delicate balance that
was struck by the parties in structuring
the negotiated rulemaking agreement"
(Joint Explanatory Statement of the
Committee on Conference on S. 1316,
p2). An additional factor that must be
considered in this context is that
Congress affirmed the need for
microbial ground water regulations but
also clearly contemplated that such
standards might not be promulgated
until issuance of Stage 2 DBPR (no later
than May, 2002).
Alternative Approaches
In light of the 1996 SDWA
amendments and their conflicting
implications for different elements of
the compliance strategy agreed to by the
Negotiating Committee and set forth in
the 1994 IESWTR and Stage 1 DBPR
proposals, EPA is today requesting
comment on four alternative compliance
approaches. The Agency also requests
comment on any other compliance
approaches or modifications to these
options that commenters believe may be
appropriate.
-------
Federal Register / Vol. 62. No. 212 /Monday November 3. 1997 / Proposed Rules 59519
OPTION 1.—IMPLEMENT 1994 PROPOSAL SCHEDULE
Rule
(promulgation)
DBF 1 (11/98)
IESWTR (11/98)
LTESWTR (11/00)
GWDR (11/00)
Surface water PWS
S10k
5/00
5/00
15/02
NA
<10k
5/02
NA
5/02
NA
Ground water PWS
S10k
5/02
NA
NA
(2)
<10k
11/03
NA
NA
(2)
1 (If required).
2 Not addressed.
Option 1 (schedule as proposed in
1994) simply continues the compliance
strategy laid out in the 1994 Stage 1
DBPR and IESWTR proposals. This
would provide that medium and large
surface water PWSs (those serving at
least 10,000 people) comply with the
final Stage 1 DBPR and IESWTR within
18 months after promulgation, and that
surface water systems serving fewer
than 10,000 comply within 42 months
of Stage 1 DBPR promulgation. This
option also would provide that ground
water systems serving at least 10,000
and that disinfect comply within 42
months, while ground water systems
serving fewer than 10,000 comply
within 60 months.
This approach was agreed to by EPA
and other stakeholder members of the
1992 Negotiating Committee. However,
it has been at least in part superseded
by both the general 36 month PWS
compliance period and the 24 month
State adoption and implementation
period provided under the 1996 SDWA
amendments. If the proposed 1994
compliance schedule were to be
retained, EPA would need to make a
determination that the statutory
compliance provision of 36 months was
not necessary for large and medium
surface systems because compliance
within 18 months is "practicable". To
maintain simultaneous compliance, the
Agency would also have to make the
same practicability determination for
small surface water systems in
complying with the LTESWTR and for
ground water systems serving at least
10,000 in complying with the GWDR. In
addition, the Agency would need to
justify 42 months for small surface
water systems and 60 months for small
ground water systems with disinfection
by making a national determination that
the additional time was required due to
the need for capital improvements at
each of these small systems. EPA also
would need to articulate a rationale for
why States should not be provided the
statutorily specified 24 months to
implement new complex regulatory
provisions before PWSs are required to
comply. Finally, to implement this
approach, the Agency would be
required to modify the timing associated
with the microbial backstop provision
agreed to on July 15. 1997 by the M-
DBP Advisory Committee (since a 18
month schedule would not allow time
after promulgation for medium surface
water systems (10,000-99,999) to collect
HAA data prior to having to determine
whether disinfection benchmarking is
necessary).
EPA requests comment on the issues
outlined above in connection with this
option. In particular, the Agency
requests comment and information to
support a finding that compliance by
specified systems in 18 months is
practicable for some rules, and that
extensions to 42 or 60 months for other
systems are required to allow for capital
improvements.
OPTION 2.—ADD 18 MONTHS TO 1994 PROPOSAL SCHEDULE
Rule
(promulgation)
DBP 1 (11/98)
IESWTR (1 1/98)
LTESWTR (1 1/00)
GWDR (11/00)
Surface water PWS
£10k
11/01
11/01
1 11/03
NA
<10k
11/03
NA
11/03
NA
Ground water PWS
S10k
11/03
NA
NA
<2)
<10k
5/05
NA
NA
(2)
1 (If required).
2 Not addressed.
Option 2 (each date in proposed 1994
compliance strategy extended by 18
months) reflects the fact that the 1996
SDWA amendments generally extended
the previous statutory deadlines by 18
months (to three years) and established
an overall compliance period not to
extend beyond 5 years. This second
approach would result in simultaneous
compliance for surface water systems.
Large surface water systems (those
serving at least 10,000) would have
three years to comply in accordance
with the baseline 3 year compliance
period established under Section
1412(b)(10) of the 1996 Amendments.
Small surface water systems (under
10,000) would be required to comply
with Stage 1 D/DBPR requirements
within five years and applicable
LTESWTR requirements within three
years. Since the LTESWTR will be
promulgated two years after Stage 1
DBPR (in accordance with the new
SDWA M-DBP regulatory deadlines
discussed above), the net result of this
approach is that small surface water
systems would be required to comply
with both Stage 1 DBPR and IESWTR
requirements by the same end date of
November 2003, thus assuring
simultaneous compliance. This meets
the objective of both the reg-neg process
and Congress to address risk-risk
tradeoffs in implementing new M-DBP
requirements.
USEPA believes that providing a five
year compliance period for small
surface water systems under the Stage 1
DBPR is appropriate and warranted
under section 1412(b)(10), which
expressly allows five years where
necessary for capital improvements. Of
necessity, capital improvements require
-------
59520 Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules
preliminary planning and evaluation.
Such planning requires, perhaps most
importantly, identification of final
compliance objectives. This then is
followed by an evaluation of
compliance alternatives, site
assessments, consultation with
appropriate state and local authorities,
development of final engineering and
construction designs, financing, and
scheduling. In the case of the staggered
M-DBP regulatory schedule established
as part of the 1996 SDWA amendments,
LTESWTR microbial requirements for
small systems are required to be
promulgated two years after the
establishment of Stage 1DBPR
requirements. Under these
circumstances, small systems will not
even know what their final combined
M-DBP compliance obligations are until
Federal Register publication of the final
LTESWTR. As a result, an .additional
two year period reflecting the two year
Stage 1 DBPR/LTESWTR regulatory
development interval established by
Congress is required to allow for
preliminary planning and evaluation
which is an inherent component of any
capital improvement process. EPA
believes this approach is consistent with
both the objective of assuring
simultaneous compliance and not
exceeding the overall statutory
compliance period of five years. This
same logic would also apply to ground
water systems serving at least 10,000,
since such systems would need the final
GWDR to determine and implement a
compliance strategy.
With regard to extended compliance
schedules, EPA notes that the economic
analysis developed as part of the M-
DBP Advisory Committee indicates that
there will be capital costs associated
with implementation of both the
IESWTR as well as the Stage I DBF
rules. As outlined above, the 1996
SDWA amendments provide that a two
year extension may be provided by EPA
at the national level or by States on a
case-by-case basis if either EPA or a
State determines that additional time is
necessary for capital improvements.
EPA does not believe there is data
presently in the record for either of
these rulemakings to support a national
determination by the Agency that a two-
year extension is justified. EPA requests
comment on this issue and, if a
commenter believes such an extension
is warranted, requests that the
comments provide data to support such
a position.
Adding 18 months to the 1994
proposed compliance strategy would
result in 78 month (six and a half year)
compliance period for small ground
water systems. This is beyond the
.overall five year compliance period
established by Congress under Section
1412(b)(10). EPA is not aware of a
rationale to support this result that is
consistent with both the objectives of
the reg-neg process and the new SDWA
amendments; however, the Agency
requests comment on this issue. As
discussed below, EPA believes there is
a reasonable compliance strategy for
addressing ground water systems that
reflects the requirements of the SDWA
amendments as well as the intent of the
reg-neg process.
OPTION 3.—REQUIRE COMPLIANCE WITH ALL RULES WITHIN THREE YEARS OF PROMULGATION
Rule
(promulgation)
DBF 1 (11/98)
IP«flA/TR MIMftt
LTESWTR (11/00)
GWDR (11/00)
Surface water PWS
&10k
11/01
11/01
111/03
NA
<10k
11/01
NA
11/03
NA
Ground water PWS
SlOk
11/01
NA
NA
11/03
<10k
11/01
NA
NA
11/03
«(If required).
Under this approach, all systems
would be required to comply with Stage
1 DBPR, IESWTR. and LTESWTR within
three years of final promulgation. This
approach reflects the baseline three year
compliance period included as part of
the new SDWA compliance provisions.
Unlike option 2 outlined above which
simply adds an 18 month extension to
the 1994 proposed compliance
approach, this option is not tied to the
1994 proposal. Rather it applies the new
baseline three year compliance period to
the staggered M-DBP regulatory
development schedule which was also
established as part of the 1996 SDWA
amendments.
This approach would result in
simultaneous compliance for large
surface water systems. However, it
would eliminate the possibility of
simultaneous compliance for small
surface water systems and all ground
water systems. Contrary to reg-neg
objectives and Congressional intent, it
would create an incentive for risk/risk
tradeoffs on the part of small surface
water systems who would be required to
take steps to comply with Stage 1 DBPR
provisions two years before coming into
compliance with the LTESWTR, and for
all ground water systems who would be
required to take steps to comply with
Stage 1 DBPR provisions two years
before coming into compliance with the
GWDR.
OPTION 4.—MERGE SDWA PROVISIONS WITH NEGOTIATED RULEMAKING OBJECTIVES
Rule
(promulgation)
DBF 1 (11/98)
IP<5WTR M1/9ftt
ITF^WTR M1/0rrt .
GWDR (11/00)
Surface water PWS
£10k
11/01
11/01
•"11/03
NA
<10k
11/03
NA
11/03
NA
Ground water PWS
SlOk
11/03
NA
NA
11/03
<10k
11/03
NA
NA
11/03
1 (If required).
This option combines the principle of
simultaneous compliance with the
revised compliance provisions reflected
in the 1996 SDWA amendments. Large
surface water systems would be
required to comply with Stage 1 DBPR
-------
Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules
59521
and IESWTR within 3 years of
promulgation, thus assuring
simultaneous compliance and
consistency with the baseline statutory
compliance period of 3 years. Small
surface water systems under 10,000
would comply with the provisions of
the Stage 1 DBPR at the same time they
are required to come into compliance
with the analogous microbial provisions
of the LTESWTR. This would result in
small surface water systems
simultaneously complying with both the
LTESWTR and Stage 1 DBPR
requirements. Under this approach,
small systems would comply with
LTESWTR requirements three years
after promulgation and Stage 1 DBPR
requirements five years after
promulgation. For the reasons
articulated under option two above,
EPA believes providing a five year
compliance period under Stage 1 DBPR
is appropriate and necessary to provide
for capital improvements.
For ground water systems, the 1994
proposed Stage 1 DBPR compliance
schedules provided for only one half of
the risk-risk tradeoff balance. They did
not include a companion rule
development and compliance schedules
for the analogous microbial provisions
of a Ground Water Disinfection Rule.
The 1996 SDWA amendments provide
an outside date for promulgation of
ground water microbial requirements of
"no later than" May 2002, but leave to
EPA the decision of whether an earlier
promulgation is more appropriate. In
light of the reg-neg emphasis and
Congressional affirmation of the
principal of simultaneous compliance to
assure no risk-risk tradeoffs, EPA has
developed a ground water disinfection
rule promulgation schedule that will
result in a final GWDR by November
2000, the same date as the
Congressional deadline for the
LTESWTR. Ground water systems
would be required to comply with the
GWDR by November 2003, three years
after promulgation, and to assure
simultaneous compliance with DBF
provisions, such systems would be
required to comply with Stage 1 DBPR
requirements by the same date. Again,
for the reasons outlined under option 2,
USEPA believes a five year compliance
period for ground water systems is
necessary and appropriate.
Option 4 assures that ground water
systems will be required to comply with
Stage 1 DBPR provisions at the same
time that they comply with the
microbial provisions of the Ground
Water Disinfection Rule (GWDR).
Successful implementation of this
option requires that EPA develop and
promulgate the GWDR by November
2000 as indicated above. The Agency
recognizes that this is an ambitious
schedule, but believes it is necessary to
meet the twin objectives of
simultaneous implementation and
consistency with the new statutory
compliance provisions of the 1996
SDWA. In evaluating this option, the
Agency also considered the possibility
of meeting these twin objectives in a
somewhat different fashion by delaying
final promulgation of the Stage I DBF
rule as it applies ground water systems
until the promulgation of the GWDR.
This alternative possibility would
assure simultaneous compliance and
also provide a "safety net" in the event
that the GWDR November 2000
promulgation schedule is delayed. EPA
is concerned, however, that this
approach may not meet or be consistent
with new SDWA requirements which
provide tfiat the Stage I DBPR be
promulgated by November 1998. The
Agency requests comment on this issue.
Recommendation
EPA has evaluated each of the
considerations identified in Options 1
through 4. On balance, the Agency
believes that Option 4 is the preferred
option. The primary reasons are (1) to
allow States at least two years to adopt
and implement M-DBP rules consistent
with new two year time frame provided
for under the 1996 SDWA amendments,
(2) to match the compliance schedules
for the LTESWTR and Stage 1 DBPR for
small (<10,000 served) surface water
systems to allow time for capital
improvements and addressing risk-risk
tradeoff issues, and (3) to assure that all
ground water systems simultaneously
comply with newly applicable microbial
and Stage 1 DBPR requirements on the
same compliance schedule provided for
small surface water systems.
Request for Comments
EPA requests comment on both the
compliance schedule options discussed
above and on any other variations or
combinations of these options. EPA also
requests comment on its preferred
option 4 and on the underlying rationale
for allowing a five year compliance
schedule for ground water and small
surface water systems under the Stage 1
DBPR.
B. Compliance Violations and State
Primacy Obligations
A public water system that fails to
comply with any applicable
requirement of the SDWA (as defined in
1'414 (I)) is subject to an enforcement
action and a requirement for public
notice under the provisions of section
1414. Applicable requirements include,
but are not limited to, MCLs, treatment
techniques, monitoring and reporting.
These regulatory requirements are set
out in 40 CFR141.
The SDWA also requires States that
would have primary enforcement
responsibility for the drinking water
regulations ("primacy") to adopt
regulations that are no less stringent
than those promulgated by EPA. States
must also adopt and implement
adequate procedures for the
enforcement of such regulations, and
keep records and make reports with
respect to these activities in accordance
with EPA regulations. 5 U.S.C. 1413.
EPA may promulgate regulations that
require States to submit reports on how
they intend to comply with certain
requirements (e.g., how the State plans
to schedule and conduct sanitary
surveys required by the IESWTR), how
the State plans to make certain
decisions or approve PWS-planned
actions (e.g., approve significant
changes in disinfection under the
IESWTR or approve Step 2 DBF
precursor removals under the enhanced
coagulation requirements of the Stage I
DBPR), and how the State will enforce
its authorities (e.g., correct deficiencies
identified by the State during a sanitary
survey within a specified time). The
primacy regulations are set out in 40
CFR 142.
EPA drafted requirements for both the
PWSs (part 141) and the primacy States
(part 142) in the proposed rules. EPA is
requesting comments on whether there
are elements of the Advisory
Committee's recommendations in this
Notice that should be treated as
applicable requirements for the PWS
and included in part 141 as enforceable
requirements. Similarly, EPA requests
comments on whether there are
elements of the Advisory Committee's
recommendations in this Notice that
should be treated as requirements for
States and included in part 142 as
primacy requirements.
C, Compliance With Current Regulations
EPA reaffirms its commitment to the
current Safe Drinking Water Act
regulations, including those related to
microbial pathogen control and
disinfection. Each public water system
must continue to comply with the
current rules while new microbial and
disinfectants/disinfection byproducts
rules are being developed.
M. Disinfection Studies
1. New Giardia Inactivation Studies at
High pH Levels
The Surface Water Treatment Rule
(SWTR) requires plants treating surface
-------
59522 Federal Register / Vol. 62. No. 212 / Monday November 3, 1997 / Proposed Rules
water to meet minimum inactivation/
removal requirements for Giardia cysts
and viruses. Under the SWTR. the
concept of CT values (disinfectant
residual concentration (C) multiplied
by contact time CO) is used for
estimating inactivation efficiency of
disinfection practices in plants. As a
supplement to the rule, USEPA
published a guidance manual document
entitled "Guidance Manual for
Compliance with the Filtration and
Disinfection Requirements for Public
Water Systems Using Surface Water
Sources" (USEPA 1991a) [SWTR
Guidance Manual]. In this manual, CT
tables (Log inactivation versus CT
values under different environmental
conditions) are provided to utilities as a
guidance in carrying out the
disinfection requirements.
The SWTR Guidance Manual did not
include CT values at pH values above 9
due to the limited research results
available at the time of rule
promulgation. pH values above 9 mainly
exist in plants with lime softening
processes. An approach for extending
the existing CT tables in the SWTR
Guidance Manual to the upper pH
boundary (pH 11.5) that may occur in
some plants is presented below. With
this approach, the latest available data
reported by Logsdon et al. (1994) was
used as a basis for CT values at high pH
values by applying a linear regression to
Logsdon's experimental results in
laboratory water and a safety factor to
cover the variability in natural water.
Analysis oFLogsdon's Data: Logsdon
etal. (1994) performed Giardia
Inactivation experiments with free
chlorine in both laboratory and natural
waters at 5°C and at pH values of 9.5,
10.5, and 11.5. The analysis of MW-s's
data is performed with the following
assumptions:
1. Since the experimental data of MW-
s et .al. for CT values vs. log inactivation
are relatively scattered, a sophisticated
model will not improve the result of
simulation. Rather, a linear regression
was used to fit these data points, by
assuming the dilution coefficient n=l in
the conventional Watson's Law (first-
order kinetics).
2. Data points for inactivation greater
than 3-logs in the Logsdon et al. report
are not included in the linear regression
because of their uncertainty.
3. Data points for natural water have
a greater variability than those for
laboratory water. Also, CT tables in the
SWTR Guidance Manual were
developed solely based on tests using
laboratory water. To ensure consistency,
therefore, data points for natural water
from the Logsdon et al. study were not
used. However, a safety factor was
applied to the CT values estimated from
laboratory data to reflect the variability
of inactivation results in natural water.
4. To be consistent, the safety factor
of CT values at pH > 9 is assumed to be
the same as that for the existing CT
values in the SWTR Guidance Manual at
pH 5 9. To appropriately quantify a
safety factor being applied to obtain
those existing CT values in the SWTR
Guidance Manual, the previous data
base for pH <, 9 was reevaluated and
interpreted in the same manner as that
for pH > 9 (using a linear regression and
a safely factor). Subsequently, the safety
factor was set at a value such that, if
multiplied by the CT values estimated
by a linear regression, the resultant CT
values would match the existing CT
values in die SWTR Guidance Manual.
5. For determination of a safety factor,
data from the following studies were
considered: Jarroll et al. (1981), Rice et
al. (1982), Hibler et al. (1987), and
Rubin et al. (1989) [Those data were
used as a basis for developing the
existing CT values in the SWTR
Guidance Manual.]. Only the data from
Jarroll et al. (1981) were used in the
linear regression because the protocols
or conditions in other studies are not
comparable to those used in the study
by Logsdon et al. (1994), as noted below:
(1) The study by Hibler et al. (1987) was
based on animal infectivity tests. Excystation
was used in the study by Logsdon et al.
(1994).
(2) The study by Rubin et al. (1989) was
conducted only at 15°C while the study by
Logsdon et al. (1994) was performed at 5°C.
(3) No data for control excystation was
shown in the study by Rice et al. (1982) and
therefore this data was not used in the
regression analysis.
The data from Jarroll et al. (1981) for
chlorine concentrations of 4 and 8 mg/
L were not used in the regression
analysis because the chlorine residual in
the study by Logsdon et al. (1994) was
no higher than 2.1 mg/L.
The Results of Data Analysis: The
data from Jarroll et al. (1981) pertaining
to log inactivation versus CT values are
plotted in Figures 8—10 for pH values
of 6, 7, and 8, respectively. Because
Jarroll et al. found that essentially no
inactivation at pH values of 6-8 was
observed in control samples in which
no disinfectant was added within 60
minutes (i.e., CT = 0, log inactivation =
0), the intercept of the linear regression
line was zero.
BILLING CODE 6S60-60-P
-------
Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules
59523
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-------
59524 Federal Register / Vol. 62. No. 212 / Monday November 3, 1997 / Proposed Rules
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-------
Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules
59525
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BILLING CODE 6560-50-C
The regression results with the values
of the Watson coefficient k are shown in
each figure. Based on these results, CT
values for a designated log inactivation
at the three different pH values are
estimated and shown in Table 6. By
trials, it is found that if a safety factor
of 1.5 is applied to those estimated CT
values, the resulting CT values
approximate the values in the SWTR
Guidance Manual for chlorine
concentration <, 2 mg/L: at pH 6, the
safety-factored CT values are slightly
higher than those in the SWTR
Guidance Manual; at pH 7, the safety-
factored CT values are about in the
middle of the range of CT values in the
SWTR Guidance Manual; at pH 8, the
safety-factored CT values are in the low
range of CT values in the SWTR
Guidance Manual. Therefore, a safely
factor of 1.5 appears appropriate for the
development of CT tables at higher pHs.
BILLING CODE 6560-50-P
-------
59526 Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules
Table 6: Comparison of Estimated CT Values (Based on the Jarroll's Study) and Values in
the Manual for C £ 2 mg/L for pH=6-8 at 5 °C
PH
pH-6
pH=7
pH-8
Loglnactivatlon
... ' ';>^y\p. r/X^ '
0.5
1
1.5
2
2.5
3
0.5
1
1.5
2
2.5
3
0.5
1
1.5
2
2.5
3
Estimated CT, mg-
. min/L -
14
29
44
58
73
88
17
34
52
69
86
103
23
45
68
91
114
136
Estimated CTx 1,5
Safety Factor
21
43
66
87
110
132
26
51
78
104
129
154
34
68
102
136
171
204
CT In Guidance Manna!
for C £ 2 mg/L ::
16-19
32-39
49-58
65-77
81-97
97-116
23-28
46-55
70-83
93-110
116-138
139-165
33-41
66-81
99-122
132-162
165-203
198-243
B1UUNQ CODE eWO-SO-C
The Logsdon data for Giardia
inactivation with chlorine are shown in
Figures 11-13 for pH values of 9.5.10.5,
and 11.5. respectively. Since Logsdon et
al. (1994) also observed that little or no
inactivation was caused by a high pH
itself (i.e., non-disinfected lime softened
water) in at least 6 hours, the intercept
of the linear regression line should be
zero. Based on the determinant k values
indicated in each Figure, CT values
required for inactivation in the range of
0.5-3 log at pH values of 9.5-11.5 and
temperature of 5°C are estimated and
tabulated in Table 7. To evaluate the
adequacy of the safety factor value (1.5),
the line of log inactivation versus the
safety-factored CT values is also shown
in each of Figures 11-13. It can be seen
from Figures 11 and 12 tfiat most data
points for natural water are above the
safety-factored line, and few points are
near the line, indicating the safety factor
of 1.5 is appropriate for the
establishment of CT tables for pH > 9.
BILLING CODE 6660-50-P
-------
Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules
59527
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-------
59528 Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules
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-------
Federal Register / Vol. 62. No. 212 / Monday November 3, 1997 / Proposed Rules 59529
Ijl
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BILLING CODE 6S60-SO-C
TABLE 7.—ESTIMATED CT VALUES
FOR pH=9.5-11.5 AT C < 2 mg/L
AND AT 5°C—BASED ON THE
LOGSDON'S STUDY FOR LABORA-
TORY WATER
PH
pH=9.5 ...
pH=10.5
Log inac-
tivation
0.5
1
1.5
2
2.5
3
0.5
1
1.5
2
Estimated
CT mg-
min/L
21
42
62
83
104
125
70
141
211
282
Estimated
CTx1.5
S.F.
32
63
93
124
156
188
105
212
316
423
TABLE 7.—ESTIMATED CT VALUES
FOR pH=9.5-11.5 AT C ^ 2 mg/L
AND AT 5°C—BASED ON THE
LOGSDON'S STUDY FOR LABORA-
TORY WATER—Continued
PH
pH=11.5
Log inac-
tivation
2.5
3
0.5
1
1.5
2
2.5
3
Estimated
CTmg-
tnin/L
352
422
128
256
385
513
641
769
Estimated
CTx1.5
S.F.
528
633
192
384'
578
770
962
1154
By comparing the data in Table 6 and
10, it is seen that estimated CT values
at pH 9.5 are consistently lower than
those at pH 8 in the SWTR Guidance
Manual. To maintain the consistency of
an increasing trend of CT values with an
increasing pH and be conservative for
compliance purposes, the mathematical
model described in the SWTR Guidance
Manual (equation 15 in Appendix F) by
Clark and Regli (1993) is used to extend
the existing CT tables in the SWTR
Guidance Manual to pH=9.5, e.g.,
CT=60 mg/L for 0.5 log inactivation
with 1 mg/L of chlorine at 5°C. As
proposed in the SWTR Guidance
Manual, the equation can be directly
applied to estimate CT values for 0.5
and 5°C, and a twofold decrease in CT
values for every 10°C increase in
temperature can be assumed when it is
higher than 5°C. Consequently, the CT
-------
59530
Federal Register / Vol. 62, No. 212 / Monday November 3. 1997 / Proposed Rules
values for Glardia inactivation with free
chlorine at pH 9.5 are computed and
shown In Table 8.
The same temperature correction
factor above is used to estimate CT
values for pH values of 10.5 and 11.5 at
temperature from 5 to 25°C. and 1.5 of
temperature factor is applied to convert
CT values at 5°C to those at 0.5°C.
Subsequently, the safety-factored CT
values for Giardia inactivation with free
chlorine were estimated and
summarized in Tables 11 and 13 for pH
values of 10.5 and 11.5, respectively. It
should be mentioned that although the
level of chlorine residual (the C value)
may affect CT values shown in Tables
12 and 13, it is recommended that those
values are only applicable to a C value
up to 3 mg/L, at least until more
research data become available.
BIUNG CODE 6S60-60-P
-------
Federal Register / Vol. 62. No. 212 / Monday November 3. 1997 / Proposed Rules 59531
Table 8: CT Values. (mg-min/L) for Inactivation of Giardia by Free Chlorine at pH 9.5
C, mg/L
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
2.2
2.4
2.6
2.8
3
. . Log Inactivation at 0.5 °C
', •' • ',' ¥ • ' -
9J5~ ,:_•:$:. ":$&•'••'. .2 2$ 3.0'
74 149 223 297 371 446
79 158 237 316 395 474
82 165 247 330 412 494
85 170 256 341 426 511
88 175 263 350 438 525
90 179 269 358 448 538
91 183 274 366 457 549
93 186 279 372 465 558
95 189 284 378 473 567
96 192 288 384 480 575
97 194 292 389 486 583
98 197 295 393 492 590
99 199 298 398 497 597
100 201 301 402 502 603
'• '.-'"C>.
• ,. .,mgiflL::.:
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
2.2
2.4
2.6
2.8
3
Log Inactivation at 5 °C
::.0% ' 1 .•;...;l*f/f •,•!-. .'2.5 m
53 105 158 210 263 315
56 112 168 224 279 335
58 117 175 233 292 350
60 121 181 241 302 362
62 124 186 248 310 372
63 127 190 254 317 381
65 129 194 259 324 388
66 132 198 264 329 395
67 134 201 268 335 402
68 136 204 272 339 407
69 138 206 275 344 413
70 139 209 278 348 418
70 141 211 282 352 422
71 142 213 285 356 427
Continued
a
. ™SfL
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
2.2
2.4
2.6
2.8
3
Log Inactivation at 10 "C
0.5 1 1.5 2 2.5 3.0
35 70 105 140 175 210
37 75 112 149 186 224
39 78 117 156 194 233
40 80 121 161 201 241
41 83 124 165 207 248
42 85 127 169 211 254
43 86 129 173 216 259
44 88 132 176 220 264
45 89 134 178 223 268
45 91 136 181 226 272
46 92 138 183 229 275
46 93 139 186 232 278
47 94 141 188 235 282
47 95 142 190 237 285
a
rag/L
0.4
0.6
0.8
1.
1.2
1.4
1.6
1.8
2
2.2
2.4
2-6
2.8
3
Log Inactivation at 15 °C
0.5 1 . 1.5 2 2.5 m
26 53 79 105 131 158
28 56 84 112 140 168
29 58 88 117 146 175
30 60 90 121 151 181
31 62 93 124 155 186
32 63 95 127 159 190
32 65 9s! 129 162 194
33 66 99 132 165 198
33 67 100 134 167 201
34 68 102 136 170 204
34 69 103 138 172 206
35 70 104 139 174 209
35 70 106 141 176 211
36 71 107 142 178 213
Table 8: CT Values (mg-min/L) for Inactivation of Giardia by Free Chlorine at pH 9.5
-------
59532
Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules
Continued
c,
mg/L
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
2.2
2.4
2.6
2.8
3
Lo& laacttvation at 20 °C
0.5 1 1.5- 2 2.5 3.0
21 42 63 84 105 126
22 45 67 89 112 134
23 47 70 93 117 140
24 48 72 97 121 145
25 50 74 99 124 149
25 51 76 102 127 152
26 52 78 104 129 155
26 53 79 105 132 158
27 54 80 107 134 161
27 54 81 109 136 163
28 55 83 110 138 165
28 56 84 111 139 167
28 56 84 113 141 169
28 57 85 114 142 171
"'• :-. . . .-•• *
•: .";.'/»' •'.; •
•••••••;•%•».•.•
mgtL-
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
2.2
2.4
2.6
2.8
3
Dag.faactivation at 2S.°C
0.5:* ': fi-;. i.s:'Fl.v..:.2 ;, 2.5 3.0
18 35 53 70 88 105
19 37 56 75 93 112
19 39 58 78 97 117
20 40 60 80 101 121
21 41 62 83 103 124
21 42 63 85 106 127
22 43 65 86 108 129
22 44 66 88 110 132
22 45 67 89 112 134
23 45 68 91 113 136
23 46 69 92 115 138
23 46 70 93 116 139
23 47 70 94 117 141
24 47 71 95 119 142
-------
Federal Register / Vol. 62, No, 212 / Monday November 3, 1997 /Proposed Rules
59533
Table 9: CT Values (mg-min/L) for Inactivation otGiardia by Free Chlorine at pH 10.5
'?*%?•'.:
0.5
5
10
15
20
25
•::.?> •• - Log Inactivation (^pH^lO^S : •:•
0,5
131
105
79
53
39
26
1
265
212
159
106
80
53
"l:S. '
395
316
237
158
119
79
•' 2- ••••'•:
395
316
237
158
119
79
2,5
529
423
317
212
159
106
3.0
660
528
396
264
198
132
Table 10: CT Values (mg-min/L) for Inactivation ofGiardia by Free Chlorine at pH 11.5
1;^%
0.5
5
10
15
20
25
:-;•.. >-r.:- •:• -u^iBaoij^!^jp^|^=>^:..- -.-=..••.
v 0.5
240
192
144
96
72
48
1"
480
384
288
192
144
96
vefcS; -•"•
723
578
434
289
217
145
v; :':£.•:
963
770
578
385
289
193
lo^'-l'S' •;:
1203
962
722
481
361
241
. 3.0
1443
1154
866
577
433
289
BILLING CODE 6560-50-C
In summary, the CT table for Giardia
inactivation with free chlorine at pH 9.5
was developed by using the same
approach in the SWTR Guidance
Manual for the existing CT tables at
lower pH values. For the development
of CT tables at pH values of 10.5 and
11.5, the data reported by Logsdon et al.
(1994) was used with a linear regression
multiplied by a safety factor of 1.5. The
new CT values are shown in Tables 11,
12, and 13 for pH values of 9.5, 10.5,
and 11.5, respectively. USEPA solicits
comment on the approach taken and
whether the CT values shown in Tables
11, 12 and 13 are appropriate for
revising existing guidance for estimating
inactivation efficiencies for chlorine at
pHs above 9. USEPA also solicits
comment on other approaches for
developing criteria by which systems
could estimate inactivation efficiencies
at pHs above 9.
2. Effectiveness of Different
Disinfectants on Cryptosporidium
When the ESWTR was proposed in
1994, USEPA recognized that chlorine
disinfectants were relatively ineffective
in inactivating Cryptosporidium, but
was not certain if alternative
disinfectants might be more effective
than chlorine. No public comment
addressed this issue directly. Studies
since the proposal have confirmed the
ineffectiveness of chlorine species, such
as free chlorine and monochloramine,
for the practical inactivation of
Cryptosporidium. However, new data
suggest that sequential disinfection with
free chlorine followed by
monochloramine can achieve a greater
degree of Cryptosporidium inactivation
than by chlorine alone. Moreover, ozone
and chlorine dioxide have been found to
Be much more effective than chlorine.
Sequential disinfection such as ozone or
chlorine dioxide followed by one of the
chlorine species appears more powerful
than either disinfectant alone in
inactivating Ciyptosporidium. The
following data detail the inactivation of
Cryptosporidium by individual
disinfectants, as well as by sequential
disinfectants.
The purpose of presenting this data in
this section is to provide the public
opportunity to comment on whether
there is (a) sufficient information
available for generating CT tables to
estimate log inactivation of
Cryptosporidium, comparable to what
was done for Giardia under the SWTR,
and (b) sufficient data to conclude that
chlorination, at levels commonly
practiced by utilities, is virtually
ineffective for inactivating
Cryptosporidium. Both of these issues
relate to USEPA's rationale for using
Giardia as the key target organism for
defining the disinfection benchmark
(see Section D).
Table 1 la summarizes the data on
disinfection of Cryptosporidium with
-------
59534
Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules
chlorine species and ultraviolet
radiation (UV). The results from studies
with free chlorine indicate that some
Inactivatlon of C. parvtun could be
achieved at relatively high doses of
chlorine (I.e., >1,000 mg/L of chlorine
bleach and 80 mg/L of free chlorine)
(Korich et al., 1990a; Ransome et al.,
1993) and a high CT value (7.200 mg-
min/L) (Korich et al., 1990a; Lykins et
al., 1992). However, this common water
disinfectant has been conclusively
shown to be ineffective for inactivation
of C. parvum oocysts at practical plant
doses (<6 mg C12/L) or CT values
(Korich et al., 1990a; Ransome et al.,
1993; Finch et al., 1997). The same is
essentially true for monochloramine
(Lykins et al., 1992; Finch et al., 1997)
and the oxidant of permanganate (Finch
et al., 1997). Therefore, it is unlikely
that significant inactivation of
Cryptosporidium will occur in water
treatment plants with the single
addition of these disinfectants at
currently used levels.
BILLING CODE 6560-SO-P
-------
Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules
59535
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onatal CD-I m
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o
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on 2 um filter
00
*
BILUNG CODE 6560-50-C
-------
59536
Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules
As Indicated in Table lla, the
literature data on Ctyptosporidium
Inactivation with UV appear
controversial because of different
experimental protocols used by different
Investigators. Finch et al. (1997) found
that UV was ineffective in inactivating
C. parvum suspended in a batch reactor.
However, significant inactivation was
observed when the oocysts were
captured in 2cm filters and exposed to
a preset UV irradiation dose (Campbell
et al., 1995; Clancy et al., 1997). More
data are needed to evaluate the practical
application of UV for inactivation of
Cryptosporidium oocysts. Also, of
interest are possible synergistic effects
with UV application followed by
residual disinfectants.
Table 1 Ib summarizes the findings of
inactivation of Cryptosporidium with
ozone. The data obtained from bench-
scale tests with oxidant-demand-free
laboratory water indicate that for CT
values between 1.2-23.0 mg-min/L, the
range of inactivation was 0.5 to 5 log at
temperatures of 5 to 25 °C and at pH
values of 7 to 8 (Peelers et al., 1989;
Korich et al., 1990a,b; Parker et al.,
1993; Ransome et al., 1993; Finch et al.,
1994 & 1997). The variability
demonstrated in these results is
influenced by the differences in test
procedures used by different
researchers, i.e., the different measures
of Cryptosporidium inactivation
(infectivity, excystation, etc.) and the
different methods of CT calculations
(initial ozone dose, average ozone
concentration, and ozone residual).
BILLING CODE 6560-50-P
-------
Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules
59537
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•^-
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^ u
li
IB
BILLING CODE 6560-50-C
-------
59538
Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules
Therefore, caution should be used
when comparing the results from one
study to another. For Instance, a CT
value of 10 mg-min/L for 0.5-log
Inactlvatlon was obtained from the
study conducted by Parker et al. (1993),
who used vital dyes to evaluate the
viability of Cryptosporidium. This result
Is incomparable to the data shown in
Table lib. Subsequently, Korich et al.
(1993) found that vital stains are of
questionable value for determining
oocyst viability.
In another example, in a series of
experiments at pH 7 and at temperatures
of 5-22 °C. Finch et al. (1997) found a
45-92% reduction in ozone
concentration at initial residuals of 0.6-
2.2 mg/L and contact times of 5-15
minutes. Parker et al. (1993) reported
that the Cryptosporidium inactivation
level was greater when the ozone
concentration was maintained at a
constant level (i.e., through a batch
mode reactor), compared to when the
same initial ozone dose was allowed to
decay during the same contact time.
Both Finch et al. (1994) and Parker et al.
(1993) found that an increase in
temperature caused a higher
Inactivation at the same ozone residual
mid the same contact time. It appears
that an increase of 15 °C decreases by
half the CT values needed for a 2-log
inactivation.
Owens et al. (1994) observed that C.
murls is slightly more resistant to ozone
than C. parvum, and proposed that C.
murls be used as a surrogate model for
C. parvum. However, the data that
support this hypothesis are very limited.
Two pilot-scale studies with natural
waters have been performed (Danial et
al., 1993; Miltner et al., 1997). The CT
values of ozone required to achieve 2-
and 3-logs inactivation of
Cryptosporidium were 6.0 mg-min/L
(pH 8, 24 °C) (Miltner et al., 1997) and
10-15 mg-min/L (pH 7, 15 °C) (Danial
et al., 1993). It appears that higher CT
values are required in natural water for
inactivation of Cryptosporidium than in
laboratory water; this may be attributed
to the existing oxidant demands in
natural water or other factors. Danial et
al. (1993) indicated that the ozone
residual for a given dose rapidly
decomposed as the pH was increased
from 7 to 9 during lime addition. This
finding implies that if ozonation is
practiced in lime-softening water plants,
it will be necessary to adjust the pH
downstream.
When inactivation of
Cryptosporidium oocysts is compared
with that of Giardia cysts with similar
test protocols, C. parvum is
approximately 10 times more resistant
to ozone than G. lamblia in laboratory
water (Finch et al., 1994) and G. muris
in natural water (Owens et al., 1994;
Miltner et al., 1997). These findings
imply that the use of ozone cannot be
expected to significantly inactivate
Cryptosporidium at the concentration
and contact times employed in
inactivating Giardia in water treatment
practices.
Table 1 Ic summarizes the findings of
Cryptosporidium inactivation with
chlorine dioxide. For CT values between
23-213 mg-min/L, the range of
inactivation is 0.5-3.2 log or higher at
temperatures of 10-25 °C and at pH
values of 7-8 in laboratory water
(Peeters et al., 1989; Korich et al., 1990b;
Ransome et al., 1993; Finch et al., 1995
& 1997). Similar to ozone, chlorine
dioxide is also unstable in the water. In
0.05 M phosphate buffer water at pH 8
and 22 °C, Finch et al. (1997) found that
a 49-99% reduction in chlorine dioxide
concentrations occurs after 15-120
minutes at initial residuals of 0.36-3.3
mg/L. LeChevallier et al. (1997b)
recently performed a pilot-scale study in
a natural water by evaluating viability of
oocysts with both an in-vitro
excystation assay and a tissue culture
infectivity. While the difference in
results with the two methods was not
shown, the study reported that a CT
value of 40 mg-min/L results in 1-log
inactivation of oocysts at pH 8.0 and
20°C, and a 0.5-log inactivation at pH
6.0. The study also revealed that a
temperature reduction from 20 to 10 °C
decreases the effectiveness of chlorine
dioxide by 40%.
The existing data show chlorine
dioxide as an effective disinfectant for
Cryptosporidium inactivation. However,
CT values required for Cryptosporidium
inactivation appear much higher than
those for same log inactivation of
Giardia under comparable water
conditions (Lisle and Rose, 1995). Since
the 1994 D/DBP proposed rule has set
the maximum contaminant levels for
chlorine dioxide and chlorite (by-
product of chlorine dioxide), at 0.8
mg/L and 1 mg/L, respectively, the use
of chlorine dioxide may be limited for
the inactivation of Cryptosporidium.
BILLING CODE 6660-50-P
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Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules 59539
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BILLING CODE 6E60-50-C
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59540 Federal Register / Vol. 62, No. 212 / Monday November 3. 1997 / Proposed Rules
Table 12 summarizes the results from
Finch et al. (1997). Finch et al. found
that sequential disinfection of C.
parvum oocysts by different
disinfectants is more effective than that
indicated by the effectiveness of each
disinfectant from independent studies,
I.e., the effect is synergistic. According
to their current report, greater than 2.9-
log inactivation of oocysts can be
achieved when C. parvum is exposed to
0.75 mg/L initial ozone residual for 3.7
minutes and then 2.0 mg/L free chlorine
residual for 265 minutes (pH 6). Based
on the additive effects of ozone and free
chlorine alone under similar conditions,
a 2.0-logs inactivation is expected.
Similarly, the inactivation by
monochloramine following ozonation is
increased by 1.5 log-units when
compared with either ozone or
monochloramine alone.
Additional 1.2-log inactivation due to
the synergism of chlorine dioxide and
free chlorine has also been obtained at
pH 8. Furthermore, sequential exposure
of C. parvum .oocysts to free chlorine
followed by a monochloramine (pH 8.0)
reduces infectivity by 0.6 log. Since the
expected inactivation by either chlorine
species at pH 8 is virtually zero, there
is a synergism between free chlorine
and monochloramine. It should be
noted that combinations of chlorine
species with other disinfectants may
stimulate the formation of chlorate
(Siddiqui et al., 1996) or other toxic
disinfectant byproducts. Also, the
synergistic effect with sequential
disinfectants has only been observed in
bench-scale studies in a single
laboratory. Nevertheless, such findings
suggest new strategies for the effective
inactivation of Cryptosporidium. For a
practical application, further
investigations are being conducted at a
wider range of water quality conditions
(pH, temperature, and disinfectant
demand) (USEPA, 1995b).
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Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules 59541
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BILLING CODE 6560-50-C
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59542 Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules
Analytical Method—Four analytical
methods are currendy being used to
evaluate inactivation of
Cryptosportdium oocysts: in vitro
excystation. vital dyes (DAPI/PI
staining), animal infectivity, and tissue
culture infectivity. It has been shown
that excystation and DAPI/PI staining
consistently underestimate inactivation
when compared wtth animal infectivity,
which is more expensive (Finch et al.,
1994; Black et al., 1996). The use of
different animal models also leads to
Inconsistent results for Cryptosporidium
Infectivity. Although the tissue culture
technique may provide a convenient,
low-cost alternative to animal
infectivity, only limited data exist with
this method (LeChevallier et al., 1997b).
Cryptosporidium Inactivation Map-
In conjuncdon with development of the
long-term ESWTR. USEPA is developing
a graph of CT values versus log
inactivation under various water quality
conditions. The Agency is also
exploring other means that utilities can
use to estimate Cryptosporidium
Inactivation with different single or
sequential disinfectants. Additional
data, especially under natural water/
field conditions, is necessary to develop
this graph. Finch et al. (1994) attempted
to establish CT tables for
Cryptosportdium inactivation with
ozone by analyzing numerous sets of
experimental data by using both the
Chick-Watson model and the Horn
model. It was found that the
inactivation kinetics of C. parvum by
ozone deviated from the simple first-
order Chick-Watson model and was
better described by a nonlinear Horn
model. A further analysis, however,
hasn't been performed on a broader data
basis to evaluate such a finding.
Moreover, a much better understanding
of Cryptosporidium inactivation with
sequential disinfectants is needed.
3. New Virus Inactivation Studies
One of the treatment options that
USEPA proposed as part of the ESWTR
was to include a 4-logs minimal
inactivation requirement for viruses, in
addition to any physical removal of
viruses that might be achieved. USEPA
intends to consider this option when
additional data become available.
However, significant data are available
regarding disinfection conditions
necessary to achieve different
inactivation levels of viruses. The
availability of such data is discussed
below.
USEPA's guidance manual to the
SWTR (USEPA, 1991a), assumes that CT
values for chlorine necessary to achieve
a 0.5-log inactivation of Giardia cysts
will result in greater than a 4-log
inactivation of viruses. This assumption
is based on the comparison between the
effects of free chlorine on Giardia
lamblia and hepatitis A virus (HAV). In
the proposed ESWTR, USEPA noted
that some viruses are more resistant to
chlorine than is HAV, and the use of
disinfectants other than free chlorine to
achieve 0.5-log inactivation of Giardia
may not yield a 4-log inactivation of
viruses. Achieving adequate
inactivation of viruses may be of greater
concern when disinfectants other than
chlorine (e.g., chlorine dioxide and
ozone) are used to inactivate
Cryptosporidium oocysts.
CT tables in the SWTR for estimating
viral inactivation efficiency with
chlorine dioxide and ozone were based
on laboratory studies using HAV and
poliovirus 1, respectively. Very few
studies have since been conducted to
investigate viral inactivation with
chlorine dioxide. Huang et al. (1997)
evaluated the disinfection effects of
chlorine dioxide on six viruses,
including poliovirus type 1,
coxsackievirus type 63, echovirus 11,
adenovirus type 7, herpes simplex virus
1, and mumps virus. All viruses were
completely inactivated at CT=90 mg-
min/L (3 mg/L of initial dose and 30
minutes of contact time) at pH values of
3, 5, and 7, but not 9. Complete
inactivation of all six viruses was also
found at CT=30 mg-min/L (1 mg/L of
initial dose and 30 minutes of contact
time) at pH 7.0. At 7.0 mg/L of initial
dose, greater than 10 minutes of contact
time were required for complete
inactivation at the same pH.
More studies have been performed to
evaluate viral inactivation efficiencies
by ozone than by chlorine dioxide. The
results from these studies are
summarized in Table 13.
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59543
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59544
Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules
In general, the tested viruses,
including HAV, MS2 coliphage,
poltovirus 1 (PV1), poliovirus 3 (PV3),
and T2 phage, are relatively sensitive to
ozone, and more than 4-logs
inactivatlon of these viruses can be
achieved with less than 2 mg/L of ozone
and 5 minutes of contact time in a wide
range of pH values and temperatures
(Herbold et al.. 1989; Kaneko, 1989;
Vaughn et al., 1990; Finch et al., 1992;
Hall and Sobsey, 1993; Miltner et al..
1997). Finch et al. (1992) reported that
MS2 coliphage was extremely sensitive
to, ozone in both laboratory water and
natural water, and that complete viral
inactivation could occur during the
process of satisfying ozone demand in
natural water. In paired experiments,
they also found that there was
significantly less inactivation of PV3
than MS2 coliphage under the same
ozonatlon conditions. In contrast, Hall
and Sobsey (1993) demonstrated that
MS2 coliphage was at least as resistant
to ozone as HAV in a pH range of 6-10,
suggesting that MS2 coliphage might be
a good model for predicting HAV
inactivation by ozone. In a continuous-
flow system with a constant flow of
ozone and viral suspensions, Herbold et
al. (1993) found that HAV required
approximately three times the ozone
that PV1 required for the same
inactivation. In a similar system,
Botzenhart et al. (1993) showed that
MS2 coliphage was more resistant to
ozone than PhiX 174 coliphage.
Some researchers have pointed out
that viral disinfection with ozone is
difficult to evaluate, not only due to the
relatively short inactivation times, but
also because the concentration of ozone
significantly decreases during the
contact time. Finch et al. (1992) found
ozone dose and the interaction between
ozone dose and dissolved organic
carbon (DOC) were the most important
factors affecting ozone inactivation of
MS2 coliphage in surface waters.
Inactivation of MS2 coliphage was
significantly reduced when the natural
DOC in the water Increased during
spring runoff, presumably because the
ozone concentration was rapidly
depleted by the DOC. This effect,
however, was not observed when an
ozone residual of 0.1 mg/L at the end of
30 seconds was detected, resulting in
greater than 4-logs inactivation of MS2
coliphage under all water quality
conditions.
Finch et al. (1992) found that the
effects of temperature and turbidity on
inactivation rates were
indistinguishable from experimental
error. This contrasts with other studies
that reported that viral inactivation with
ozone was more efficient at lower
temperatures (Botzenhart etal., 1993;
Herbold et al., 1993), and the presence
of kaolin particles at 1 mg/L or higher
resulted in a greater level of ozone
residual required for the same level of
viral inactivation (Kaneko, 1989).
Vaughn et al. (1990) observed that the
pH-related effects on ozonation of
viruses was not significant in a pH range
of 6-8. Kaneko (1989) reported that the
presence of ammonium decreased the
ozone concentration and thus decreased
the inactivation efficiency of ozone.
Kaneko (1989) also revealed that
ozonation of viruses could be divided
into three phases: an initial large
reduction of viruses; a subsequent
logarithmic reduction of viruses; and
finally, a slow reduction in response to
decreasing ozone concentrations. Thus,
it is not surprising that the viral
inactivation rate beginning 5 minutes
after adding the disinfectant was greater
with chlorine than with ozone, even
though the inactivation rates within 5
minutes of the addition of ozone were
10 to 1,000 higher than the initial rates
of inactivation with chlorine (Kaneko
andlgarashi, 1983; Kaneko, 1989).
Finch et al. (1992) have concluded
that, when comparing the ozone
inactivation data for MS2 coliphage,
PV3, and Giardia muris, the conditions
for inactivating G. muris cysts are the
most rigorous and it is likely that enteric
viruses will be inactivated by greater
than 4 logs when Giardia is inactivated
by 3 logs. Such a comparison is also
needed for chlorine dioxide. Although
the tested enteric viruses appear to be
more susceptible to ozone than Giardia,
no data are yet available on the
effectiveness of ozone in inactivating
Norwalk virus and other pathogenic
human viruses, especially when they
are clumped and adsorbed to organic
matter as they usually are in natural
water. The varying results on viral
inactivation with ozone suggest that
ozone inactivation studies need to
measure and report ozone
concentrations over time.
III. Economic Analysis of the M-DBP
Advisory Committee Recommendations
A. Overview of RIA for Proposed Rule
The Regulatory Impact Analysis (RIA)
for the proposed IESWTR (59 FR 38832,
July 29, 1994), estimated national
capital and annualized costs (amortized
capital and annual operating costs) for
surface water systems serving at least
10.000 people at $3.6 billion and $391
million respectively. These costs were
based on the assumption that systems
would also be required to provide
enough treatment to achieve less than a
10~4 risk level from giardiasis while
meeting the Stage 1 DBPR. In estimating
these costs, it was assumed that
additional Giardia reduction beyond the
requirements of the SWTR to achieve
the 10 ~4 risk level would be achieved
solely by using chlorine as the
disinfectant and providing additional
contact time by increasing the
disinfectant contact basin size.
The Regulatory Impact Analysis for
the Interim Enhanced Surface Water
Treatment Rule (USEPA, 1994d)
predicted tiiat ESWTR compliance
would result in no more than a few
hundred infections caused by
waterborne Giardia per year per 100
million people. This is hundreds of
thousands of cases fewer than predicted
in the absence of an ESWTR. USEPA
estimated that the benefit per Giardia
infection avoided would be $3000 per
case. Using this estimate, the 400,000 to
500,000 Giardia infections per year that
could be avoided would have an
economic value of $1.2 to $1.5 billion
per year. This suggests that the benefit
nationwide of avoiding Giardia
infections is as much as three or four
times greater than the estimated $391
million national annual cost of
providing additional contact time.
Table 14 shows this $391 million
estimated cost as described in the
proposal (using 1992 $s and a discount
rate of 10 percent). The table also
converts this cost to 1997$s (with a 10
percent discount rate) to provide for
comparison with costs based on
provisions included in diis notice.
For a more detailed discussion of the
cost and benefit analysis of the 1994
proposal refer to The Regulatory Impact
Analysis for the Interim Enhanced
Surface Water Treatment Rule (USEPA,
1994d).
B, What's Changed Since the Proposed
Rule
The cost estimates in the proposed
rule reflect cost estimates for one of
several regulatory alternatives included
in the proposal. At the time of proposal
USEPA assumed that additional data
would be collected under the ICR to
more accurately estimate costs and
benefits of the Giardia based rule option
as well as alternative regulatory options.
National source water occurrence data
for Giardia and Cryptosporidium are
being collected as part of the ICR to help
this effort. Due to the delays discussed
earlier in this Notice and the new
expedited rule deadlines, ICR data will
not be available for the IESWTR impact
analysis. From February 1997, however,
the Agency has worked with
stakeholders to identify additional data
available since 1994 to be used in
developing components of the
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59545
expedited rules. USEPA established the
Microbial and Disinfectants/
Disinfection Byproducts Advisory
Committee to collect, share and analyze
new information and data, as well as to
build consensus on the regulatory
implications of this new information.
The Committee met five times from
March to July, 1997 to discuss issues
related to the IESWTR and Stage ID/
DBPR.
USEPA has also evaluated comments
received on the proposal in its
consideration of elements to be
included in a regulatory option
independent of ICR source water
occurrence data. These comments
suggested (1) sufficient degrees of
effectiveness of current treatment,
including filtration, in'preventing
waterborne transmission of
Cryptosporidium and (2) a revised
approach focussing on optimizing
treatment processes. In response to
these comments, new information
received and the Advisory Committee's
recommendations, USEPA has
developed die Economic Analysis
described in summary below. Details of
the analysis used to derive the costs and
benefits described below are available in
the draft document Economic Analysis
of M/DBP Advisory Committee
Recommendations for the Interim
Enhanced Surface Water Treatment Rule
(USEPA, 1997a). The economic analyses
are based on the Committee's
recommendations to USEPA on issues
including turbidity control, removal of
Cryptosporidium, disinfection
benchmarking and sanitary surveys.
C. Summary of Cost Analysis
1. Total National Costs
USEPA is considering several
approaches, based on the
recommendations of the Advisory
Committee. The two most substantial
approaches, from the perspective of
costs and benefits, govern turbidity
performance and turbidity monitoring.
The Microbial and Disinfectants/
Disinfection Byproducts Committee
made a number of recommendations
that are indicated in this Notice for
comment, including new turbidity
provisions with associated monitoring
requirements, disinfection
benchmarking practices to help ensure
there are no significant increases in
microbial risk while systems comply
witfi the Stage 1 DBPR and a sanitary
survey provision of relatively minimal
costs. USEPA estimates that the national
capital and annualized costs (amortized
capital and annual operating costs) of
these provisions (based on a 10 percent
interest rate) would be $730 million and
$312 million, respectively [Table 14]
(USEPA, 1997a). These figures include
costs associated with improved
treatment, turbidity monitoring, a
disinfection benchmark and sanitary
surveys. This represents a reduction of
over $3.4 billion (in 1997 $s) from die
capital costs estimated for the proposed
rule. This is accounted for primarily by
die recommendations for changes in the
level of disinfection required and
restoration of disinfection credit prior to
precursor removal. This would result in
fewer systems needing to install
additional disinfectant contact basins,
relative to the costs in the 1994
proposal.
A discount rate of 10 percent was
used to calculate the unit costs for die
national cost model. This discount rate
provides both a link to the 1994
IESWTR cost analyses and is a
reasonable estimation of die cost to
utilities to finance capital purchases
assumed to be necessary due to the
proposal.
In order to demonstrate the sensitivity
of the national cost model to different
discount rates, the national costs at 10
percent are compared to national costs
calculated using a 7% discount rate.
This rate represents die standard social
discount rate preferred by the Office of
Management and Budget for benefit-cost
analyses of government programs and
regulations. Tables of unit cost estimates
at the 7 percent rate are included in the
appendix to the draft Economic
Analysis and displayed for comparative
purposes (USEPA, 1997a). Costs
presented in die Economic Analysis are
expressed in June 1997 constant dollars.
The water flow rates that were used
in calculating die costs of die 1994
proposal (in 1992 $s and 1997 $s) were
also used in calculating die national
costs of die recommended provisions
discussed in this Notice. Additional
analyses gauged the sensitivity of die
cost model to a different input value for
maximum flow rates for die largest
system category (systems serving >1
million people). Widi this adjusted flow
rate (using a 10 percent discount rate)
total annualized national costs would be
$314 million, compared to $312 million
based on flow rates used in the 1994
proposal.
USEPA requests comment on how the
new data have been used and any
additional data that would improve die
assessment of costs and benefits.
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59546 Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules
Table 14: Costs of the Interim Enhanced Surface Water Treatment Rule (SOOO)
'.'- '••••• • ./... <;:•.,.• . "? '£" •', '
UtllltyCdsts ..;•;;;.. i^':,-^
Total Utility Treatment Capital
Annual Utility Costs
Annualized Capital
Annual O&M
Total Treatment
Turbidity Monitoring
Total Annual Utility Costs
One-Time Utility Costs
Turbidity Monitoring Start-up
Disinfection Benchmarking
Advisory Committee Recommendations
(1997 Ss)
10 Percent
discount rate
''t , -
730,802
101,834
101,102
202,936
95.982
298,918
' 7 Percent
discount rate
'
191,251
95.982
287,233
4,291
2,691
4,291
2,691
10 Percent
w/adjusted
flow rates)
I"
205,124
95.982
301,106
4,291
2,691
1994 Proposal
1997 Ss
(10 percent
discount rate)
< "•
4,139,555
442,231
442,231
1992 Ss
(7 percent
discount
rate)
3,665,568
391,702
391,702
State Co jfr ..' 7^';T "'•*•};•• -"r !.<"•? "'
Annual State Costs
Turbidity Monitoring
IFAs and CPEs
Sanitary Survey
One-Time State Costs
Start-up/Implementation 1
Disinfection Benchmarking
Summary of Total Cost* ""- *>'
Utility Costs
Total Annual
One-Time
State Costs
Total Annual
One-Time
Total One^imfe;C6stir:;i;:- . ,". .•'•%& 'I
Total Annual Costs .ivii'^s.>. • ^rM^-
:>: :! £,"•': v
5,257
547
6,781
407
3,112
v *• • ;
298,918
6,983
12,585
3,519
t!;.to£0fc ;•<;
•. ...jiiis'dj; •:..-..
*, ^
5,257
547
6,781
407
3,112
* t"* f
287,233
6,983
12,585
3,519
10)SOl
299,818
* °^ f
5^57
547
6,781
407
3,112
1 ,
301,106
6,983
12,585
3,519
i&,$dj
313,691
4 '
979
3*057
„
442,231
979
3,057
3,057
- 443,210
867
2,708
-.':.'•.
391,702
867
2,70$:;: .-
392,5«9:;:^,;;;.
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59547
2. Household Costs
Household costs are a way to
represent water system treatment costs
as a costs to the system customer. Figure
14 displays results of the household cost
analyses for a 0.3 NTU, 1 maximum CFE
NTU turbidity treatment approach
discussed in this Notice. As can be seen
from the graph, a small percentage of
the systems might, using this
methodology, incur a maximum cost per
household of approximately $ 110 per
year. The highest household costs are
incurred in households served by small
systems that need to implement all of
the activities to comply.
It must be borne in mind that die
upper bound of the graph displays an
extrapolated curve, and does not
represent actual data points. The
assumptions and structure of this
analysis, in describing die curve, tend to
overestimate the highest costs. To find
itself on the upper bound of the curve,
a system would have to implement all,
or almost all, of die treatment activities.
These systems, conversely, might seek
less cosdy alternatives, such as
connecting into a larger regional water
system. In the judgment of die Advisory
Committee's Technical Work Group,
this extreme situation and die resulting
high values may occur only for a small
number of households.
Based on tills analysis, over 97
percent of die households are estimated
to incur annual costs of less dian $20
per household per year and over 50
percent are estimated to incur costs of
less dian $2 per household per year.
BILLING CODE 6560-50-P
Figure 14: Cumulative Percentage of Household Costs
$120
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Cumulative Percent
BILLING CODE 6660-50-C
D. Cost of Turbidity Performance
Criteria and Associated Monitoring
1. System Level Impact Analysis
The TWG developed a list of
treatment activities that systems would
be expected to employ in order to
implement Advisory Committee
recommendations. These activities were
grouped into 10 categories based on
general process descriptions as follows;
chemical addition, coagulant
improvements, rapid mixing,
flocculation improvements, settling
improvements, filtration improvements,
hydraulic improvements, administration
culture improvements, laboratory
modifications and process control
testing modifications. Descriptions of '
how systems were expected to evaluate
diese activities are described in die draft
document Technologies and Costs for
the Interim Enhanced Surface Water
Treatment Rule (USEPA, 1997b).
2. National Impact Analyses
a. Decision Tree. The decision tree is
a table of treatment activities diat taken
either singly or in combination will help
utilities evaluate what is potentially
involved in meeting die turbidity limits
recommended by the Advisory
Committee, i.e., the requirement tiiat
utilities serving more dian 10,000
people be required to achieve a 95
percentile turbidity limit of 0.3 NTU
and at no time exceed a turbidity value
of 1 NTU (Appendix A, USEPA, 1997a).
Percentages in a decision tree represent
die projected percentage of public water
systems using that activity to meet die
turbidity limits recommended by die
Advisory Committee. These percentages
were factors in die national cost model
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59548 Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules
and generally represent the percentage
of systems needing to modify treatment
to meet the limits.
Further description of the compliance
decision tree and methodology are
Included In the draft Economic Analysis
of M/DBP Advisory Committee
.Recommendations for the Interim
Enhanced Surface Water Treatment Rule
(Economic Analysis) (USEPA. 1997a).
b. Utility Costs. Turbidity Treatment.
The number of systems, the associated
total capital costs, and the associated
total annualized costs were estimated
for seven system size categories. Total
annual costs were calculated for each
possible treatment activity and for each
system size category. Unit costs were
converted to annualized cost totals (in
thousands of dollars) using the
methodology described in the draft
Economic Analysis.
As indicated in Table 14, the estimate
of national annualized turbidity
treatment costs are $203 million based
on the Advisory Committee's
recommended 0.3 NTU 95th percentile
CFE standard while meeting a 1 NTU
maximum combined filter effluent level
(calculated with a 10% interest rate in
1997SS).
Turbidity Monitoring. A generalized
turbidity monitoring model was
developed to provide a framework for
estimating costs associated with
Individual filter monitoring. The model
assumes turbldimeters for each filter
and an on-line Supervisory Control And
Data Acquisition (SCADA) system.
Filter readings would be taken at least
once every 15 minutes and tabulated.
The model assumes that once each work
shift (8 hours) the turbidity data would
be converted to a reviewable form, and
would then be reviewed by a system
manager. In cases where the monitoring
recorded exceedances as described
below, a report would be made to the
State and. 5 warranted, an individual
filter review or system assessment might
occur. Annual utility monitoring costs
are estimated at $96 million as shown
in Table 14 above.
Under the approach recommended by
the Advisory Committee, exception
reporting to the State is warranted if:
—An individual filter has a turbidity
level greater than 1.0 NTU for 2
consecutive measurements 15
minutes apart.
—An individual filter has a turbidity
level greater than 0.5 NTU at the end
of the first 4 hours of filter operation
for 2 consecutive measurements 15
minutes apart.
—If a plant reports exceedances of 1.0
NTU at one filter for 3 consecutive
months, an individual filter
assessment (IFA) is required to be
performed by the utility.
—If a plant records exceedances of 2.0
NTU at one filter in 2 consecutive
months, a comprehensive
performance evaluation (CPE) is
required and must be performed by a
third party.
c. State Costs. Annual Review Costs.
Under the recommended provisions, it
would be the State's responsibility to
review system data to ensure that all
systems in the State are in compliance
with the provisions. State activities
include compliance tracking, review of
Statewide utility data, record keeping,
and compliance determinations. Annual
State costs for review (nationwide) are
estimated to be $5.3 million (USEPA,
1997a).
Implementation and Start-Up Costs
Related to Turbidity Monitoring. One-
time State implementation activities
include the adoption of the rule and
State regulation development. As shown
in Table 14, the rule would collectively
cost States a total of $407,000 to
implement turbidity monitoring
provisions.
Exception Costs (Exception Reports,
IFAs and CPEs). Under the approach
recommended by the Advisory
Committee, a monthly exception report
would be filed by each utility at which
a plant exceeds individual filter effluent
(IFE) turbidities of either 1.0 NTU for 2
consecutive measurements 15 minutes
apart, or 0.5 NTU at the end of the first
4 hours of a filter run.
In addition to the monthly exception
report of individual filter effluent
exceedances, additional steps are
triggered when exceedances persist. If
an individual filter has turbidity levels
greater than 1.0 NTU based on 2
consecutive measurements fifteen
minutes apart at any time in each of 3
consecutive months, the system
conducts a self assessment of the filter
utilizing as guidance relevant portions
of guidance issued by the
Environmental Protection Agency for
Comprehensive Performance Evaluation
(CPE). If an individual filter has
turbidity levels greater than 2.0 NTU
based on 2 consecutive measurements
fifteen minutes apart at any time in each
of two consecutive months, the system
will arrange for the conduct of a CPE by
the State or a third party approved by
the State.
The following assumptions were
made by the Technical Working Group
of the Advisory Committee regarding
the percentage of systems per year that
would trigger an interaction with the
State based on the recommended
provisions.
—10 percent of systems per year are
assumed to file monthly reports to the
State based on individual filter
effluent provisions
—2 percent of systems per year are
assumed to trigger Individual Filter
Assessment (IFA) provisions
—1 percent of systems per year are
assumed to trigger Comprehensive
Performance Evaluation (CPE)
provisions.
Based on these assumptions,
approximately 28 IFAs and 14 CPEs will
be conducted each year at an estimated
cost of $5,000 and $25,000 each,
respectively. States are expected,
therefore, to incur annual costs
(nationally) of $64,000 to review die
exception reports, $138,000 and
$345,300 in annual costs for IFAs and
CPEs, respectively. The combined total
annual State cost for these items is
$572,000 (Table 14, above).
E. Disinfection Benchmark
1. Decision Tree
The Advisory Committee
recommended that a utility prepare a
disinfection profile if they:
—measure TTHM levels of at least 80
percent of the MCL (0.064 mg/1) as an
annual average for the most recent 12-
month period for which compliance
data are available.
—measure HAA% level of at least 80
percent of the MCL (0.048 mg/1) as an
annual average for the most recent 12-
month compliance period for which
compliance data are available.
HAA and TTHM figures from the
1996 Water Industry Data Base (WIDB)
were used to estimate the percentage of
systems that would be required to
prepare a disinfection profile.
2. Utility Costs
Utility costs associated with profiling
were divided into four activity areas;
cost per system, cost per plant using
paper data (i.e., for those plants that
currently use paper to document their
plant profile data), cost per plant using
mainframe data, and cost per plant
using PC data. Plants witii paper data
were assumed to represent half of the
number of plants needing profiling,
while plants with mainframe data and
plants with PC data each represent 25
percent of all plants. The TWG assumed
that all plants currently collect this data
in either an electronic or paper format,
and, therefore, would not incur
additional data collection expenses due
to microbial profiling. Data reporting
costs per plant that are associated with
microbial profiling include; data entry
and spreadsheet development, data
manipulation and analysis, and data
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Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules
59549
review. Costs per system include those
to; read and understand the rule,
mobilization and planning, generation
of reports to State and for in-house
review, and meet and review profile
with the State. The national costs
associated with microbial profiling for
utilities was estimated at $2.7 million
[Table 14].
3. State Costs
States will review profiles as part of
its sanitary survey process. Utilities
required to develop a disinfection
profile that subsequently decide to make
a significant change in disinfection
practice must consult with the state
prior to making such a change. Table 14
details the total national State costs of
profiling (one-time) at $3.1 million.
F. Sanitary Surveys
States are expected to conduct
sanitary surveys on a rotating basis, in
general no less frequently than once
every 3 years for community water
systems (CWSs) and no less frequently
than every 5 years for noncommunity
water systems (NCWSs). For this
analysis, 80 percent of Systems are
assumed to have already conducted a
sanitary survey. The remaining 20
percent of systems are considered to
require new surveys in order to comply
with the requirements in the IESWTR.
The total national cost estimate for
sanitary surveys, as shown in Table 14,
is estimated at $6.7 million.
G. Summary of Benefits Analysis
The economic benefits of the
provisions recommended by the
Advisory Committee derive from the
increased level of protection to public
health. The primary goal of these
provisions is to improve public health
by increasing the level of protection
from exposure to Cryptosporidium and
other pathogens in drinking water
supplies through improvements in
filtration at water systems. In this case,
benefits will accrue due to the
decreased likelihood of endemic
incidences of cryptosporidiosis,
giardiasis and other waterborne disease,
and the avoidance of resulting health
costs. In addition to reducing the
endemic disease, the provisions are
expected to reduce the likelihood of the
occurrence of Cryptosporidium
outbreaks and their associated economic
costs, by providing a larger margin of
safety against such outbreaks for some
systems.
The benefits analysis quantitatively
examines health damages avoided based
on the provisions recommended by the
Advisory Committee. The assessment
also discusses, but does not quantify,
other economic benefits that may result
from the provisions, including reduced
risk of outbreaks, avoided costs of
averting behavior such as boiling water.
The assessment of net benefits is
always somewhat problematic due to
the relative ease of quantifying
compliance treatment costs versus the
difficulty of assigning monetary values
to the avoidance of health damages and
other benefits arising from a regulation.
The challenge of assessing net benefits
for the recommended provisions is
compounded by the fact that there are
large areas of scientific uncertainty
regarding the exposure to and the risk
assessment for Cryptosporidium. Areas
where important sources of uncertainty
enter the benefits assessment include
the following.
• Occurrence of Cryptosporidium
oocysts in source waters.
• Occurrence of Cryptosporidium
oocysts in finished waters.
• Reduction of Cryptosporidium
oocysts due to treatment, including
filtration and disinfection.
• Viability of Cryptosporidium
oocysts after treatment.
• Infectivity of Cryptosporidium.
• Incidence of infections and
associated symptomatic response
(including impact of under reporting).
• Characterization of the risk.
• Willingness to pay to reduce risk
and avoid costs.
The cumulative impact of these
uncertainties on the outcome of the
exposure and risk assessment is
impossible to measure. The benefit
analysis attempts to take into account
some of these uncertainties by
estimating benefits under two different
current treatment assumptions and three
improved removal assumptions. The
benefit analysis also used Monte Carlo
simulations to derive a distribution of
estimates, rather than a single point
estimate.
The following two assumptions were
made about the performance of current
treatment in removing or inactivating
oocysts to estimate finished water
Cryptosporidium concentrations. The
standard assumption is that current
treatment results in a mean physical
removal and inactivation of oocysts of
2.5 logs and a standard deviation ±0.63
logs). Because the finished water
concentrations of oocysts represent the
baseline against which improved
removal from the recommended
provisions is compared, variations in
the log removal assumption could have
considerable impact on the risk
assessment. To evaluate the impact of
the removal assumptions on the
baseline and resulting improvements, an
alternative mean log removal/
inactivation assumption of 3.0 logs (and
a standard deviation ±0.63 logs) was
also used to calculate finished water
concentrations of Cryptosporidium.
USEPA made three assumptions about
the improved log removal of oocysts
that would result from the turbidity
provisions recommended by the
Advisory Committee. These were based
on studies of treatment removal
efficiencies discussed earlier in this
Notice (Table 1: Cryptosporidium and
Giardia lamblia removal efficiencies by
rapid granular filtration). A range of 2-
6 logs removal of Cryptosporidium
oocysts were observed in these studies.
USEPA assumed that a certain number
of plants would show low, mid or high
improved removal, depending upon
factors such as water matrix conditions,
filtered water turbidity effluent levels,
and coagulant treatment conditions.
The finished water Cryptosporidium
distributions that would result from
additional log removal with the
turbidity provisions were derived
assuming that additional log removal
was dependent on current removal, as
described above, i.e., that sites currently
achieving the highest filtered water
turbidity performance levels would
show the largest improvements or high
improved removal assumption (e.g.,
plants now failing to meet a 0.4 NTU
limit would show greater removal
improvements than plants now meeting
a 0.3 NTU limit). Table 15 contains the
assumptions used to generate the new
treatment distribution.
TABLE 15.—IMPROVED REMOVAL ASSUMPTIONS
Additional log removal with committee recommendations
Plants now meeting 0.2 NTU limit
Plants operating between 0.2-0.3 NTU
Plants now meeting 0.4 NTU limit
Low
None
0.15
0.35
Mid
None
0.25
0.5
High
None
0.3
0.6
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59550 Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules
TABLE 15.—IMPROVED REMOVAL ASSUMPTIONS—Continued
Additional log removal with committee recommendations
Low
0.5
Mid
0.75
High
0.9
The TWG working group assumed
that for plants to achieve a 0.3 NTU 95th
percentlle standard they would operate
their plants to achieve a 0.2 NTU limit.
Therefore, systems meeting a 95th
percentile limit of 0.2 NTU were
assumed to make no further treatment
changes to meet a 0.3 NTU standard,
and therefore show no incremental
increase in log removal.
Given the uncertainties described
above, assumptions were made in
developing the risk characterization. In
summary, USEPA assumed:
—an exponential dose/response
function for estimating infection rates
(Haas et al., 1996)
-2 liters per person daily water
consumption with a log normal
distribution (Haas and Rose, 1995)
-a national surface water distribution
of oocysts based on Monte Carlo
analysis of data collected by
LeChevallier and Norton (USEPA,
1996a)
-A uniform distribution of percentage
of oocysts that would be infectious
with a mean value of 10 percent
-An estimated 0.39 mean ratio
(triangular distribution) of people that
are infected to people that become ill
(Haas, et al., 1996).
-The cost of an avoided case of
cryptosporidiosis was estimated to be
approximately $1800 per case. This
was extrapolated from the estimate of
$3,000 for giardiasis used in the RIA
for the proposal, and based on the
relatively shorter average length of
illness.
Risk characterization uses these
assumptions to calculate the number of
illnesses avoided in Table 16. Using this
number of illnesses avoided, the cost of
illnesses avoided is calculated under
each current log treatment assumption
(i.e., 2.5 and 3.0 logs) for each of the
improved removal assumptions. Table
16 summarizes the mean expected value
of potential benefits expected to accrue
to the recommended provisions under
the six different scenarios, as well as the
range.
BILLING CODE 6660-50-P
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Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules 59551
Table 16: Summary of Potential Benefits
Current Treatment Assumption
2.5 Logs
3.0 Logs
Cost of Illness Avoided Annually , % ,' 4 , C''' -" -1
LOW (improved removal assumption)
Number of Illnesses Avoided (Expected Value)
Cost of Illness Avoided
319,000
S574.2 million
MID (improved removal assumption)
Number of Illnesses Avoided (Expected Value)
Cost of Illness Avoided
HIGH (improved removal assumption)
Number of Illnesses Avoided (Expected Value)
Cost of Illness Avoided
437,000
$786.6 million
469,000
$844.2 million
136,000
$244.8 million
165,000
$297.0 million
177,000
$318.6 million
Mortalities Prevented Annually ' f •• , '' ' - ' \ ? '"''",
Low (Expected Value)
Mid (Expected Value)
High (Expected Value)
Value of Lives Saved
Reduced Msfc Of Outbreaks ,'" " "^ > , ^
Cost of Illness Avoided
Emergency Expenditures
Liability Costs
Averting Behavior" ' '*"
•. f f ^ ? f f , _ f
r "; -", ', '"•" „'* '-*""••
' *Vv'*v^';*r;,,.
*„ ">. * -, , ,;£,/ , '--,=: ,'•*,'
"• * •" •. -,?, w"1, 's ^ f * f * * > A
48
63
67
19
23
24
Benefits not quantified, but could be substantial (estimated at
$300 million annually at 2.5 logs or $100 million at 3.0 logs).
""••'' ' ' ri i < , '«,',-' " ' '<• '&,•'
*',*•, '' *'*'. •. » ' - >>>'> 'tft
Benefits not quantified, but could be substantial for large
outbreak ($720 million cost of illness avoided for Milwaukee).
•; f f , "• f _. ff( $ j, f \
Benefits not quantified, but could be substantial for large ••
' ' , *, ' , * "'"'-••' "'
' outbreak ($i?.S million to $61.? m^^^^
'% f f ''• •" ^ ' '' ' v^
;!'/':- ' '' ', ,' ""i '"•" ;-' "»f" , „' -< *
BILLING CODE 6560-50-C
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59552 Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules
IV. National Technology Transfer and
Advancement Act
Under section 12(d) of the National
Technology Transfer and Advancement
Act ("NTTAA"). the Agency is required
to use voluntary consensus standards in
its regulatory activities unless to do so
would be inconsistent with applicable
law or otherwise impractical. Voluntary
consensus standards are technical
standards (e.g.. materials specifications,
test methods, sampling procedures,
business practices, etc.) that are
developed or adopted by voluntary
consensus standards bodies. Where
available and potentially applicable
voluntary consensus standards are not
used by EPA, the Act requires the
Agency to provide Congress, through
the Office of Management and Budget,
an explanation of the reasons for not
using such standards.
The Agency does not believe that this
Notice addresses any technical
standards subject to the NTTAA. A
commenter who disagrees with this
conclusion should indicate how the
Notice is subject to the Act and identify
any potentially applicable voluntary
consensus standards.
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63. Kaneko M and H Igarashi (1983). Effects
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72. LeChevallier MW. DN Norton, and RG
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76. Logsdon GS, JM Symons, RL Hoge, and
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(1994). The removal and disinfection
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Jour, of Parasitology, 79(1): 67-70.
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(1993). Findings of an Investigation of
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83. MacKenzle WR and NJ Hoxie, ME
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Peterson, JJ Kazmlerczak, DA Addlss, KR
Fox, JB Rose. andJP Davis (1994). A
massive outbreak In Milwaukee of
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167.
84, McGulre MJ (1994). ICR Water Treatment
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26,1997.
86. Miltner RJ. EW Rice, JH Owens. FW
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87. Montgomery Watson (1995). Enhanced
Monitoring Program; Glardia and
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88. Montgomery Watson (1996). Summary of
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July 1,1996.
89. Moore AC. BL Herwaldt, GF Craun. RL
Calderon, AK Hlghsmith. and DD
Juranek (1993). Surveillance for
waterborne disease outbreaks—United
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90. Morra JJ (1979). A Review of Water
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Open Distribution Storage Reservoirs.
Pp. 316-321.
91. Nleminskl EC (1995). Effectiveness of
Direct Filtration and Conventional
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Proceedings AWWA Annual Conf., June
1995.
92. Nlemlnski EC and JE Ongerth (1995).
Removing Glardia and Cryptosporidium
by Conventional Treatment and Direct
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93. Ongerth JE and JP Pecoraro (1995).
Removing Cryptosporidium Using
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1995), 87(12): 83-89.
94. Owens JH. RJ Mlltner. FW Schaefer m,
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95. Parker JF and HV Smith (1993).
Destruction of Oocysts of
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96. Parker JFW. GF Greaves, and HV Smith
, (1993). The effects of ozone on the
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97. Patania NL, JG Jacangelo, L Cummings, A
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99. Pluntze JC (1974). Health aspects of
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101. Regli S. JB Rose. CN Haas, and CP Gerba
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102. Regli S, BA Macler, JE Cromwell, X
Zhang, AB Gelderoos, WD Grubbs, and F
Letkiewicz (1993). Framework for
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International Life Sciences Institute
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103. Rice E, J Hoff, and F Schaefer (1982).
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Applied and Environmental
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104. Rubin AJ, DP Evers, CM Eyman, and EL
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cultured Giardia lamblia cysts by free
chlorine. Applied and Environmental
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105. SAIC (1997). State 1 and State 2
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106. Schuler PF and MM Ghosh (1990).
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107. Schuler PF and MM Ghosh (1991). Slow
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Particulates. AWWA Annual Conference
Proceedings, June 1991, pp 235-252.
108. Schulmeyer PM (1995). Effect of the
Cedar River on the Quality of
Groundwater supply for Cedar Rapids,
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109. Sethi V, P Patnaik, P Biswas, RM Clark,
and EW Rice (1997). Evaluation of
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Waterborne Suspensions. Journal
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110. Siddiqui MS (1996). Chlorine-ozone
interactions: Formation of chlorate.
Water Research, 30(9): 2160-2170.
111. Silverman GS, LA Nagy, and BH Olson
(1983). Variations in paniculate matter,
algae, and bacteria in an uncovered,
finished-drinking-water reservoir.
Journal AWWA (Apr 1983), 75(4):191-
195.
112. Smith HV, RWA Girdwood, WJ
Patterson, et al. (1988). Waterborne
outbreak of cryptosporidiosis. Lancet 2:
1484.
113. Solo-Gabriele H and S Neumeister
(1996). U.S. Outbreaks of
Cryptosporidiosis. Journal AWWA (Sept
1996), 88: 76-86.
114. Sonoma County Water Agency (1991)
Russian River Demonstration Study
(unpublished report) and Letter from
Bruce H. Burton. P.E., District Engineer,
Santa Rosa District Office to Robert F,
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116. Timms S, JS Slade, and CR Fricker
(1995). Removal of Cryptosporidium by
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117. USEPA (1979). National Interim Primary
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FR 68624, November 29, 1979.
118. USEPA (1988). Technologies and Costs
for the Treatment of Microbial
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(Oct 1988).
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59555
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Administrators (ASDWA), and National
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Assessment Procedures. October, 1995.
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144. Wilson MP, WD Gollnitz, SN Boutros,
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Dated: October 22,1997.
Robert Perciasepe,
Assistant Administrator.
Appendix A—U.S. Environmental Protection
Agency, Microbial/Disinfection by-Products
(M/DBP), Federal Advisory Committee
Agreement in Principle
1.0 Introduction
Pursuant to requirements under the Safe
Drinking Water Act (SDWA), the
Environmental Protection Agency (EPA) is
developing interrelated regulations to control
microbial pathogens and disinfectants/
disinfection byproducts (D/DBPs) in drinking
water. These rules are collectively known as
the microbial/disinfection byproducts (M/
DBF) rules.
The regulations are intended to address
complex risk trade-offs between the two
different types of contaminants. In keeping
with the agreement reached during the 1992-
93 negotiated rulemaking on these matters,
EPA issued a Notice of Proposed Rulemaking
for Disinfection By-Products Stage I on July
29, 1994. EPA also issued a Notice of
Proposed Rulemaking for an Interim
Enhanced Surface Water Treatment Rule
(IESWTR) on July 29, 1994. Finally, in May
1996, EPA promulgated a final Information
Collection Rule (ICR), to obtain data on
source water quality, byproduct formation
and drinking water treatment plant design
and operations. (
As part of recent amendments to the
SDWA, Congress has established deadlines
for all the M/DBP rules, beginning with a
November 1998 deadline for promulgation of
both the IESWTR and the Stage ID/DBP
Rule. To meet this new deadline, EPA
initiated an expedited schedule for
development of these two rules. Building on
the 1994 proposals, EPA intends to issue a
Notice of Data Availability (NODA) in
November 1997 for public comment. EPA
also decided to establish a committee under
the Federal Advisory Committee Act (FACA)
for development of the rules.
The .M/DBP Advisory Committee is made
up of organizational members (parties)
named by EPA (see Attachment A). The
immediate task of the Committee has been to
discuss, evaluate and provide advice on data,
analysis and approaches to be included in
the NODA to be published in November
1997. This Committee met four times from
March through June 1997, with the initial
objective to reach consensus, where possible,
on the elements to be contained in the D/DBP
Stage I and IESWTR NODA. Where
consensus was not reached, the Committee
sought to develop options and/or to clarify
key issues and areas of agreement and
disagreement. This document is the
Committee's statement on the points of
agreement reached.
2.0 Agreement in Principle
The Microbial and Disinfection By-
Products Federal Advisory Committee
considered the technical and policy issues
involved in developing a DBF Stage I rule
and an IESWTR under the Safe Drinking
Water Act and recommends that the
Environmental Protection Agency base the
applicable sections of its anticipated M/DBP
Notice of Data Availability (NODA) on the
elements of agreement described below.
This agreement in principle represents the
consensus of the parties on the best
conceptual principles that the Committee
was able to generate within the allocated
time and resources available.
The USEPA, a party to the negotiations.
agrees that:
1. The person signing this agreement is
authorized to commit this party to its terms.
2. EPA agrees to hold a meeting in July
1997 following circulation of a second draft
of the NODA to obtain comments from the
parties and the public on the extent to which
the applicable sections of the draft NODA are
consistent with the agreements below.
3. Each party and individual signatory that
submits comments on the NODA agrees to
support those components of the NODA that
reflect the agreements set forth below. Each
party and individual signatory reserves the
right to comment, as individuals or on behalf
of the organization he or she represents, on
any other aspect of the Notice of Data
Availability.
4. EPA will consider all relevant comments
submitted concerning the Notice(s) of
Proposed Rulemaking and in response to
such comments will make such
modifications in the proposed rule(s) and
preamble (s) as EPA determines are
appropriate when issuing a final rule.
5. Recognizing that under the
Appointments Clause of the Constitution
governmental authority may be exercised
only by officers of the United States and
recognizing that it is EPA's responsibility to
issue final rules, EPA intends to issue final
rules that are based on the provisions of the
Safe Drinking Water Act, pertinent facts, and
comments received from the public.
6. Each party agrees not to take any action
to inhibit the adoption of final rule(s) to the
extent it and corresponding preamble (s) have
the same substance and effect as the elements
of this agreement in principle.
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59556 Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules
Z.I MCLs
MCLs should remain at the levels
proposed: 0.080 mg/1 for TTHMs, 0.060 mg/
1 for HAAS, and 0.010 mg/1 for Bromate.
2.2 Enhanced Coagulation
The proposed enhanced coagulation
provisions should be revised as follows:
a. The top row of the TOC removal table
(3x3 matrix) should be modified for systems
that practice enhanced coagulation by
lowering the TOC removal percentages by
5% across the top row. while leaving the
other rows the same.
b. SUVA (specific UV absorbance) should
be used for determining whether systems
would be required to use enhanced
coagulation. The use of a raw water SUVA <
2.0 llter/mg-m as a criterion for not requiring
a system to practice enhanced coagulation
should be added to those proposed in
§141.135(a)(l)(l)-ttv).
c. For a system required to practice
enhanced coagulation or enhanced softening,
the use of a finished water SUVA < 2.0 liter/
mg-m should be added as a Step 2 procedure.
Such a criterion would be In addition to the
proposed Step 2 procedure, not In lieu of It.
d. The proposed TOC removals for
softening systems should be modified by
lowering the value for TOC removal in the
matrix at alkalinity >120 mg/1 and TOC
between 2-4 mg/1 by 5% (which would make
U equal to the value for non-softening
systems) and leaving the remaining values as
proposed.
e. If a system Is required to practice
enhanced softening, lime softening plants
would not be required to perform lime soda
softening or to lower alkalinity below 40-60.
mg/1 as part of any Step 2 procedure.
f. There is no need to separately address
softening systems In the 3x3 matrix or the
Step 1 regulatory language, which was
identical to enhanced coagulation regulatory
language In the proposed D/DBPR. The
revised matrix should appear as follows:
TOC (mg/
n
2-4
4-8
>8
A
0-<60
35
45
50
kalinity (mg,
60 -<
120
25
35
40
D
S120
15
25
30
2.3 Mlcroblal Benchmarking/Profiling
A mlcroblal benchmark to provide a
methodology and process by which a PWS
and the State, working together, assure that
there will be no significant reduction In
mlcroblal protection as the result of
modifying disinfection practices In order to
meet MCLs for TTHM and HAAS should be
established as follows:
A. Applicability. The following PWSs to
which the IESWTR applies must prepare a
disinfection profile:
(1) PWSs with measured TTHM levels of
at least 80% of the MCL (0.064 mg/1) as an
annual average for the most recent 12 month
compliance period for which compliance
data are available prior to November 1998 (or
some other period designated by the State),
(2) PWSs with measured HAAS levels of at
least 80% of the MCL (0.048 mg/1) as an
annual average for the most recent 12 month
period for which data are available (or some
other period designated by the State)—In
connection with HAAS monitoring, the
following provisions apply:
(a) PWSs that have collected HAAS data
under the Information Collection Rule must
use those data to determine the HAAS level,
unless the State determines that there is a
more representative annual data set.
(b) For those PWSs that do not have four
quarters of HAAS data 90 days following the
IESWTR promulgation date, HAAS
monitoring must be conducted for four
quarters.
B. Disinfection profi/e. A disinfection
profile consists of a compilation of daily
Glardia lamblia log inactivations (or virus
inactivations under conditions to be
specified), computed over the period of a
year, based on daily measurements of
operational data (disinfectant residual
concentration^), contact time(s),
temperature(s), and where necessary, pH(s)).
The PWS will then determine the lowest
average month (critical period) for each 12
month period and average critical periods to
create a "benchmark" reflecting the lower
bound of a PWS's current disinfection
practice. Those PWSs that have all necessary
data to determine profiles, using operational
data collected prior to promulgation of the
IESWTR, may use up to three years of
operational data in developing those profiles.
Those PWSs that do not have three years of
operational data to develop profiles must
conduct the necessary monitoring to develop
the profile for one year beginning no later
than 15 months after promulgation, and use
up to two years of existing operational data
to develop profiles.
C. State review. The State will review
disinfection profiles as part of its sanitary
survey. Those PWSs required to develop a
disinfection profile that subsequently decide
to make a significant change in disinfection
practice (i.e., move point of disinfection,
change the type of disinfectant, change the
disinfection process, or any other change
designated as significant by the State) must
consult with the State prior to implementing
such a change. Supporting materials for such
consultation must include a description of
the proposed change, the disinfection profile,
and an analysis of how the proposed change
will affect the current disinfection.
D. Guidance. EPA, in consultation with
interested stakeholders, will develop detailed
guidance for States and PWSs on how to
develop and evaluate disinfection profiles,
identify and evaluate significant changes in
disinfection practices, and guidance on
moving the point of disinfection from prior
to the point of coagulant addition to after the
point of coagulant addition.
2.4 Disinfection Credit
Consistent with the existing provisions of
the 1989 Surface Water Treatment Rule,
credit for compliance with applicable
disinfection requirements should continue to
be allowed for disinfection applied at any
point prior to the first customer.
EPA will develop guidance on the use and
costs of oxldants that control water quality
problems (e.g., zebra mussels, Asiatic clams,
Iron, manganese, algae) and whose use will
reduce or eliminate the formation of DBFs of
public health concern.
2.5 Turbidity
Turbidity Performance Requirements. For
all surface water systems that use
conventional treatment or direct filtration,
serve more than 10,000 people, and are
required to filter: (a) the turbidity level of a
system's combined filtered water at each
plant must be less than or equal to 0.3 MTU
in at least 95 percent of the measurements
taken each month and, (b) the turbidity level
of a system's combined filtered water at each
plant must at no time exceed 1 NTU. For
both the maximum and the 95th percentile
requirements, compliance shall be
determined based on measurements of the
combined filter effluent at four-hour
intervals.
Individual Filter Requirements. All surface
water systems that use rapid granular
filtration, serve more than 10,000 people, and
are required to filter shall conduct
continuous monitoring of turbidity for each
individual filter and shall provide an
exceptions report to the State on a monthly
basis. Exceptions reporting shall include the
following: (1) any individual filter with a
turbidity level greater than 1.0 NTU based on
2 consecutive measurements fifteen minutes
apart; and (2) any individual filter with a
turbidity level greater than 0.5 NTU at the
end of the first 4 hours of filter operation
based on 2 consecutive measurements fifteen
minutes apart. A filter profile will be
produced if no obvious reason for the
abnormal filter performance can be
identified.
If an Individual filter has turbidity levels
greater than 1.0 NTU based on 2 consecutive
measurements fifteen minutes apart at any
time in each of 3 consecutive months, the
system shall conduct a self-assessment of the
filter utilizing as guidance relevant portions
of guidance issued by the Environmental
Protection Agency for Comprehensive
Performance Evaluation (CPE). If an
individual filter has turbidity levels greater
than 2.0 NTU based on 2 consecutive
measurements fifteen minutes apart at any
time in each of two consecutive months, the
system will arrange for the conduct of a CPE
by the State or a third party approved by the
State.
State Authority. States must have rules or
other authority to require systems to conduct
a Composite Correction Program (CCP) and to
assure that systems implement any follow-up
recommendations that result as part of the
CCP.
2.6 Cryptosporidium MCLG
EPA should establish an MCLG to protect
public health. The Agency should describe
existing and ongoing research and areas of
scientific uncertainty on the question of
which species of Cryptosporidium represents
a concern for public health (e.g. parvum.
muris, serpententious) and request further
comment on whether to establish an MCLG
on the genus or species level.
In the event the Agency establishes an
MCLG on the genus level, EPA should make
clear that the objective of this MCLG is to
protect public health and explain the nature
of scientific uncertainty on the issue of
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Federal Register / Vol. 62, No. 212 / Monday November 3, 1997 / Proposed Rules
59557
taxonomy and cross reactivity between
strains. The Agency should indicate that the
scope of MCLG may change as scientific data
on specific strains of particular concern to
human health become available.
2.7 Removal of Cryptosporidium
All surface water systems that serve more
than 1 0,000 people and are required to filter
must achieve at least a 2 log removal of
Cryptosporidium. Systems which use rapid
granular filtration (direct filtration or
conventional filtration treatment—as
currently defined in the SWTR), and meet the.
turbidity requirements described in Section
2.5 are assumed to achieve at least a 2 log
removal of Cryptosporidium. Systems which
use slow sand filtration and diatomaceous
earth filtration and meet existing turbidity
performance requirements (less than 1 MTU
for the 95th percentile or alternative criteria
as approved by the State) are assumed to
achieve at least a 2 log removal of
Cryptosporidium.
Systems may demonstrate that they
achieve higher levels of physical removal.
2.8 Multiple Barrier Concept
EPA should issue a risk-based proposal of
the Final Enhanced Surface Water Treatment
Rule for Cryptosporidium embodying the
multiple barrier approach (e.g. source water
protection, physical removal, inactivation,
etc.), including, where risks suggest
appropriate, inactivation requirements. In
establishing the Final Enhanced Surface
Water Treatment Rule, the following issues
will be evaluated:
• Data and research needs and limitations
(e.g. occurrence, treatment, viability, active
disease surveillance, etc.);
• Technology and methods capabilities
and limitations;
• Removal and inactivation effectiveness;
• Risk tradeoffs including risks of
significant shifts in disinfection practices;
• Cost considerations consistent with the
SDWA;
• Reliability and redundancy of systems;
• Consistency with the requirements of the
Act.
2.9 Sanitary Surveys
Sanitary surveys operate as an important
preventive tool to identify water system
deficiencies that could pose a risk to public
health. EPA and ASDWA have issued a joint
guidance dated 12/21/95 on the key
components of an effective sanitary survey.
The following provisions concerning sanitary
surveys should be included.
I. Definition
(A) A sanitary survey is an onsite review
of the water source (identifying sources of
contamination using results of source water
assessments where available), facilities,
equipment, operation, maintenance, and
monitoring compliance of a public water
system to evaluate the adequacy of the
system, its sources and operations and the
distribution of safe drinking water.
(B) Components of a sanitary survey may
be completed as part of a staged or phased
state review process within the established
frequency interval set forth below.
(C) A sanitary survey must address each of
the eight elements outlined in the December
1995 EPA/STATE Guidance on Sanitary
Surveys.
II. Frequency
(A) Conduct sanitary surveys for all surface
water systems (including groundwater under
the influence) no less frequently than every
three years for community systems except as
provided below and no less frequently than
every five years for noncommunity systems.
—May "grandfather"sanitary surveys
conducted after December 1995, if
they address the eight sanitary survey
components outlined above.
(B) For community systems determined by
the State to have outstanding performance
based on prior sanitary surveys, successive
sanitary surveys may be conducted no less
than every five years.
in. Follow Up
(A) Systems must respond to deficiencies
outlined in a sanitary survey report within at
least 45 days, indicating how and on what
schedule the system will address significant
deficiencies noted in the survey.
(B) States must have the appropriate rules
or other authority to assure that facilities take
the steps necessary to address significant
deficiencies identified in the survey report
that are within the control of the PWS and
its governing body.
Agreed to by:
Name, Organization
Date
Signed By:
Peter L. Cook, National Association of Water
Companies
Michael A. Dlmltriou, International Ozone
Association
Cynthia C. Dougherty, US Environmental
Protection Agency
Mary J.R. Gilchrist, American Public Health
Association
Jeffrey K. Griffiths, National Association of
People with AIDS
Barker Hamill, Association of State Drinking
Water Administrators
Robert H. Harris, Environmental Defense
Fund
Edward G. Means m, American Water Works
Association
Rosemary Menard, Large Unfiltered Systems
Erik D. Olson, Natural Resources Defense
Council
Brian L. Ramaley, Association of
Metropolitan Water Agencies
Charles R. Reading Jr., Water and Wastewater
Equipment Manufacturers Association
Suzanne Rude, National Association of
Regulatory Utility Commissioners
Ralph Runge, Chlorine Chemistry Council
Coretta Simmons. National Association of
State Utility Consumer Advocates
Bruce Tobey, National League of Cities
Chris J. Wiant, National Association of City
and County Health Officials; National
Environmental Health Association
[FR Doc. 97-28747 Filed 10-31-97; 8:45 am]
BILLING CODE 6560-50-P
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