EPA 815-Z-OO-ODi
Monday,
April 10, 2000
Part H
Environmental
Protection Agency
40 CFR Parts 141 and 142
National Primary Drinking Water
Regulations: Long Term 1 Enhanced
Surface Water Treatment and Filter
Backwash Rule; Proposed Rule
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19046
Federal Register/Vol. 65, No. 69/Monday, April 10, 2000/Proposed Rules
ENVIRONMENTAL PROTECTION
AGENCY
40 CFR Parts 141 and 142
[WH-FRL-6570-5]
RIN 2040-AD18
National Primary Drinking Water
Regulations: Long Term 1 Enhanced
Surface Water Treatment and Filter
Backwash Rule
AGENCY: Environmental Protection
Agency (EPA).
ACTION: Proposed rule.
SUMMARY: In this document, EPA is
proposing the Long Term 1 Enhanced
Surface Water Treatment and Filter
Backwash Rule (LTlFBR). The purposes
of the LTlFBR are to: Improve control
of microbial pathogens in drinking
water, including Cryptosporidium, for
public water systems (PWSs) serving
fewer than 10,000 people; prevent
increases in microbial risk while PWSs
serving fewer than 10,000 people
control for disinfection byproducts, and;
require certain PWSs to institute
changes to the return of recycle flows
within the treatment process to reduce
the effects of recycle on compromising
microbial control. Today's proposal
addresses two statutory requirements of
the 1996 Safe Drinking Water Act
(SDWA) Amendments. First, it
addresses the statutory requirement to
establish a Long Term Final Enhanced
Surface Water Treatment Rule
(LTESWTR) for PWSs that serve under
10,000 people. Second, it addresses the
statutory requirement to promulgate a
regulation which "governs" the recycle
of filter backwash within the treatment
process of public utilities.
Today's proposed LTlFBR contains 5
key provisions for surface water and
ground water under the direct influence
of surface water (GWUDI) systems
serving fewer than 10,000 people: A
treatment technique requiring a 2-log
(99 percent) Cryptosporidium removal
requirement; strengthened combined
filter effluent turbidity performance
standards and new individual filter
turbidity provisions; disinfection
benchmark provisions to assure
continued microbial protection is
provided while facilities take the
necessary steps to comply with new
disinfection byproduct standards;
inclusion of Cryptqsporidium in the
definition of GWUDI and in the
watershed control requirements for
unfiltered public water systems; and
requirements for covers on new finished
water reservoirs,
Today's proposed LTlFBR contains
three key provisions for all conventional
and direct filtration systems which
recycle and use surface water or
GWUDI: A provision requiring recycle
flows to be introduced prior to the point
of primary coagulant addition; a
requirement for systems meeting criteria
to perform a one-time self assessment of
their recycle practice and consult with
their primacy agency to address and
correct high risk recycle operations; and
a requirement for direct filtration
systems to provide information to the
State on their current recycle practice.
The Agency believes implementing
the provisions contained in today's
proposal will improve public health
protection in two fundamental ways.
First, the provisions will reduce the
level of Cryptosporidium in filtered
finished drinking water supplies
through improvements in filtration and
recycle practice resulting in a reduced
likelihood of outbreaks of
cryptosporidiosis. Second, the filtration
provisions are expected to increase the
level of protection from exposure to
other pathogens (i.e. Giardia or other
waterborne bacterial or viral pathogens).
It is also important to note that while
today's proposed rule contains new
provisions which in some cases
strengthen or modify requirements of
the 1989 Surface Water Treatment Rule,
each public water system must continue
to comply with the current rules while
new microbial and disinfectants/
disinfection byproducts rules are being
developed. In conjunction with the
Maximum Contaminant Level Goal
(MCLG) established in the Interim
Enhanced Surface Water Treatment
Rule, the Agency developed a treatment
technique in lieu of a Maximum
Contaminant Level (MCL) for
Cryptosporidium because it is not
economically and technologically
feasible to accurately ascertain the level
of Cryptosporidium using current
analytical methods.
DATES: The Agency requests comments
on today's proposal. Comments must be
received or post-marked by midnight
June 9, 2000. Comments received after
this date may not be considered in
decision making on the proposed rule.
ADDRESSES: Send written comments on
today's proposed rule to the LTlFBR
Comment Clerk: Water Docket MC 410,
W-99-10, Environmental Protection
Agency 401 M Street, S.W., Washington,
DC 20460. Please submit an original and
three copies of comments and
enclosures (including references).
Those who comment and want EPA to
acknowledge receipt of their comments
must enclose a self-addressed stamped
envelope. No facsimiles (faxes) will be
accepted. Comments may also be
submitted electronically to ow-
docket@epamail.epa.gov. For additional
information on submitting electronic
comments see Supplementary
Information Section.
Public comments on today's proposal,
other major supporting documents, and
a copy of the index to the public docket
for this rulemaking are available for
review at EPA's Office of Water Docket:
401 M Street, SW., Rm. EB57,
Washington, DC 20460 from 9:00 a.m. to
4:00 p.m., Eastern Time, Monday
through Friday, excluding legal
holidays. For access to docket materials
or to schedule an appointment please
call (202) 260-3027.
FOR FURTHER INFORMATION CONTACT:
Technical inquiries on the rule should
be directed to Jeffery Robichaud at 401
M Street, SW., MC4607, Washington,
DC 20460 or (202) 260-2568. For
general 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 a.m. to 5:30 p.m. Eastern Time.
SUPPLEMENTARY INFORMATION: Entities
potentially regulated by the LTlFBR are
public water systems (PWSs) that use
surface water or ground water under the
direct influence of surface water
(GWUDI). The recycle control
provisions are applicable to all PWSs
using surface water or GWUDI,
regardless of the population served. All
other provisions of the LTlFBR are only
applicable to PWSs serving under
10,000 people. Regulated categories and
entities include:
Category
Industry
State, Local, Tribal or Fed-
eral Governments.
Examples of regulated entities
Public Water Systems that use surface water or ground water under the direct influence of surface water.
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19047
This table is not intended to be
exhaustive, but rather provides a guide
for readers regarding entities likely to be
regulated by the LT1FBR. This table
lists the types of entities that EPA is
now aware could potentially be
regulated by this rule. Other types of
entities not listed in this table could
also be regulated. To determine whether
your facility is regulated by this action,
you should carefully examine the
definition of public water system in
§ 141.3 of the Code of Federal
Regulations and applicability criteria in
§§ 141.76 and 141.501 of today's
proposal. If you have questions
regarding the applicability of the
LTlFBR to a particular entity, consult
the person listed in the preceding
section entitled FOR FURTHER
INFORMATION CONTACT.
Submitting Comments
Send an original and three copies of
your comments and enclosures
(including references) to W-99-10
Comment Clerk, Water Docket
(MC4101), USEPA, 401 M Street, SW.,
Washington, D.C. 20460. Comments
must be received or post-marked by
midnight June 9, 2000. Note that the
Agency is not soliciting comment on,
nor will it respond to, comments on
previously published regulatory
language that is included in this
document to ease the reader's
understanding of the proposed
language.
To ensure that EPA can read,
understand and therefore properly
respond to comments, the Agency
would prefer that commenters cite,
where possible, the paragraph(s) or
sections in the proposed rule or
supporting documents to which each
comment refers. Commenters should
use a separate paragraph for each issue
discussed.
Electronic Comments
Comments may also be submitted
electronically to ow-
docket@epamail.epa.gov. Electronic
comments must be submitted as an
ASCII, WP5.1, WP6.1 or WPS file
avoiding the use of special characters
and form of encryption. Electronic
comments must be identified by the
docket number W-99-10. Comments
and data will also be accepted on disks
in WP 5.1, 6.1, 8 or ASCII file format.
Electronic comments on this document
may be filed online at many Federal
Depository Libraries.
The record for this rulemaking has
been established under docket number
W-99-10, and includes supporting
documentation as well as printed, paper
versions of electronic comments. The
record is available for inspection from 9
a.m. to 4 p.m., Monday through Friday,
excluding legal holidays at the Water
Docket, EB 57, USEPA Headquarters,
401 M Street, SW., Washington, D.C. For
access to docket materials, please call
(202) 260-3027 to schedule an
appointment.
List of Abbreviations Used in This
Document
ASCE American Society of Civil
Engineers
ASDWA Association of State Drinking
Water Administrators
ASTM American Society for Testing
Materials
AWWA American Water Works
Association
AWWARF American Water Works
Association Research Foundation
°C Degrees Centigrade
CCP Composite Correction Program
CDC Centers for Disease Control
CFE Combined Filter Effluent
CFR Code of Federal Regulations
COI Cost of Illness
CPE Comprehensive Performance
Evaluation
CT The Residual Concentration of
Disinfectant (mg/L) Multiplied by
the Contact Time (in minutes)
CTA Comprehensive Technical
Assistance
CWSS Community Water System
Survey
DBFs Disinfection Byproducts
DBPR Disinfectants/Disinfection
Byproducts Rule
ESWTR Enhanced Surface Water
Treatment Rule
FACA Federal Advisory Committee
Act
GAG Granular Activated Carbon
GAO Government Accounting Office
GWUDI Ground Water Under the
Direct Influence of Surface Water
HAAS Haloacetic acids
(Monochloroacetic, Dichloroacetic,
Trichloroacetic, Monobromoacetic
and Dibromoacetic Acids)
HPC Heterotropic Plate Count
hrs Hours
ICR Information Collection Rule
IESWTR Interim Enhanced Surface
Water Treatment Rule
IFA Immunofluorescence Assay
Log Inactivation Logarithm of (N0/Nr)
Log Logarithm (common, base 10)
LTESWTR Long Term Enhanced
Surface Water Treatment Rule
LTlFBR Long Term 1 Enhanced
Surface Water Treatment and Filter
Backwash Rule
MCL Maximum Contaminant Level
MCLG Maximum Contaminant Level
Goal
MGD Million Gallons per Day
M-DBP Microbial and Disinfectants/
Disinfection Byproducts
MPA Microscopic Particulate Analysis
NODA Notice of Data Availability
NPDWR National Primary Drinking
Water Regulation
NT The Concentration of Surviving
Microorganisms at Time T
NTTAA National Technology Transfer
and Advancement Act
NTU Nephelometric Turbidity Unit
PE Performance Evaluation
PWS Public Water System
Reg. Neg. Regulatory Negotiation
RIA Regulatory Impact Analysis
RFA Regulatory Flexibility Act
RSD Relative Standard Deviation
SAB Science Advisory Board
SDWA Safe Drinking Water Act
SWTR Surface Water Treatment Rule
TC Total Coliforms
TCR Total Coliform Rule
TTHM Total Trihalomethanes
TWG Technical Work Group
TWS Transient Non-Community Water
System
UMRA Unfunded Mandates Reform
Act
URCIS Unregulated Contaminant
Information System
x log removal Reduction to 1/10X of
original concentration
Table of Contents
I. Introduction and Background
A. Statutory Requirements and Legal
Authority
B. Existing Regulations and Stakeholder
Involvement
1. 1979 Total Trihalomethane Rule
2. Total Coliform Rule
3. Surface Water Treatment Rule
4. Information Collection Rule
5. Interim Enhanced Surface Water
Treatment Rule
6. Stage 1 Disinfectants and Disinfection
Byproduct Rule
7. Stakeholder Involvement
II. Public Health Risk
A. Introduction
B. Health Effects of Cryptosporidiosis and
Sources and Transmission of
Cryptosporidium
C. Waterborne Disease Outbreaks In the
United States
D. Source Water Occurrence Studies
E. Filter Backwash and Other Process
Streams: Occurrence and Impact Studies
F. Summary and Conclusions
III. Baseline Information-Systems Potentially
Affected By Today's Proposed Rule
IV. Discussion of Proposed LTlFBR
Requirements
A. Enhanced Filtration Requirements
1. Two Log Cryptosporidium Removal
Requirement
a. Two Log Removal
i. Overview and Purpose
ii. Data
iii. Proposed Requirements
iv. Request for Comments
2. Turbidity Requirements
a. Combined Filter Effluent
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i. Overview and Purpose
ii. Data
iii. Proposed Requirements
iv. Request for Comments
b. Individual Filter Turbidity
i. Overview and Purpose
ii. Data
iii. Proposed Requirements
iv. Request for Comments
B. Disinfection Benchmarking Requirements
1. Applicability Monitoring
a. Overview and Purpose
b. Data
c. Proposed Requirements
d. Request for Comment
2. Disinfection Profiling
a. Overview and Purpose
b. Data
c. Proposed Requirements
d. Request for Comments
3. Disinfection Benchmarking
a. Overview and Purpose
b. Data
c. Proposed Requirements
d. Request for Comments
C. Additional Requirements
1. Inclusion of Cryptosporidium In Definition
ofGWUDI
a. Overview and Purpose
b. Data
c. Proposed Requirements
d. Request for Comments
2. Inclusion of Cryptosporidium Watershed
Requirements for Unfiltered Systems
a. Overview and Purpose
b. Data
c. Proposed Requirements
d. Request for Comments
3. Requirements for Covering New Reservoirs
a. Overview and Purpose
b. Data
c. Proposed Requirements
d. Request for Comments
D. Recycle Provisions for Public Water
Systems Employing Rapid Granular
Filtration Using Surface Water and
GWUDI as a Source
1. Treatment Processes that Commonly
Recycle and Recycle Flow Occurrence
Data
a. Treatment Processes that Commonly
Recycle
i. Conventional Treatment Plants
ii. Direct Filtration Plants
iii. Softening Plants
iv. Contact Clarification Plants
v. Package Plants
vi. Summary of Recycle Disposal Options
b. Recycle Flow Occurrence Data
i. Untreated Spent Filter Backwash Water
ii. Gravity Settled Spent Filter Backwash
Water
iii. Combined Gravity Thickener
Supernatant
iv. Gravity Thickener Supernatant from
Sedimentation Solids
v. Mechanical Dewatering Device Liquids
2. National Recycle Practices
a. Information Collection Rule
i. Recycle Practice
b. Recycle FAX Survey
i. Recycle practice
ii. Options to recycle
iii. Conclusions
3. Recycle Provisions for PWSs Employing
Rapid Granular Filtration Using Surface
Water or Ground Water Under the Direct
Influence of Surface Water Influence of
Surface Water ,
a. Return Select Recycle Streams Prior to
the Point of Primary Coagulant Addition
i. Overview and Purpose
ii. Data
iii. Proposed Requirements
iv. Request for Comments
b. Recycle Requirements for Systems
Practicing Direct Recycle and Meeting
Specific Criteria
i. Overview and Purpose
ii. Data
iii. Proposed Requirements
iv. Request for Comments
c. Requirements for Direct Filtration Plants
that Recycle Using Surface Water or
GWUDI
i. Overview and Purpose
ii. Data
iii. Proposed Requirements
iv. Request for Comments
d. Request for Additional Comment
V. State Implementation and Compliance
Schedules
A. Special State Primacy Requirements
B. State Recordkeeping Requirements
C. State Reporting Requirements
D. Interim Primacy
E. Compliance Deadlines
VI. Economic Analysis
A. Overview
B. Quantifiable and Non-Quantifiable Costs
1. Total Annual Costs
2. Annual Costs of Rule Provisions
3. Non Quantifiable Costs
C. Quantifiable and Non-Quantifiable Health
Benefits
1. Quantified Health Benefits
2. Non-Quantified Health and Non-Health
Related Benefits
a. Recycle Provisions
b. Issues Associated with Unquantified
Benefits
D. Incremental Costs and Benefits
E. Impacts on Households
F. Benefits From the Reduction of Co-
Occurring Contaminants
G. Risk Increases From Other Contaminants
H. Other Factors: Uncertainty in Risk,
Benefits, and Cost Estimates
I. Benefit Cost Determination
J. Request for Comment
VII. Other Requirements
A. Regulatory Flexibility Act
1. Today's Proposed Rule
2. Use of Alternative Definition
3. Background and Analysis
a. Number of Small Entities Affected
b. Recordkeeping and Reporting
c. Interaction with Other Federal Rules
d. Significant Alternatives
i. Turbidity Provisions
ii. Disinfection Benchmarking
Applicability Monitoring Provisions
iii. Recycling Provisions
e. Other Comments
B. Paperwork Reduction Act
C. Unfunded Mandates Reform Act
1. Summary of UMRA requirements
2. Written Statement for Rules With
Federal Mandates of $100 Million or ,
More
a. Authorizing Legislation
b. Cost Benefit Analysis
c. Estimates of Future Compliance Costs
and Disproportionate Budgetary Effects
d. Macro-economic Effects
e. Summary of EPA's Consultation with
State, Local, and Tribal Governments
and Their Concerns
f. Regulatory Alternatives Considered
g. Selection of the Least Costly, Most-Cost
Effective or Least Burdensome
Alternative That Achieves the Objectives
of the Rule
3. Impacts on Small Governments
D. National Technology Transfer and
Advancement Act
E. Executive Order 12866: Regulatory
Planning and Review
F. Executive Order 12898: Environmental
Justice
G. Executive Order 13045: Protection of
Children from Environmental Health
Risks and Safety Risks
H. Consultations with the Science Advisory
Board, National Drinking Water
Advisory Council, and the Secretary of
Health and Human Services
I. Executive Order 13132: Executive Orders
on Federalism
J. Executive Order 13084: Consultation and
Coordination With Indian Tribal
Governments
K. Likely Effect of Compliance with the
LT1FBR on the Technical, Financial, and
Managerial Capacity of Public Water
Systems
L. Plain Language
VIII. Public Comment Procedures
A. Deadlines for Comment
B. Where to Send Comment
C. Guidelines for Commenting
IX. References
I. Introduction and Background
A. Statutory Requirements and Legal
Authority
The Safe Drinking Water Act (SDWA
or the Act), as amended in 1986,
requires U.S. Environmental Protection
Agency (EPA) to publish a maximum
contaminant level goal (MCLG) for each
contaminant which, in the judgement of
the EPA Administrator, "may have any
adverse effect on the health of persons
and which is 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 the health of persons
occur and which allows an adequate
margin of safety" (Section 1412(b)(4)).
The Act was again amended in
August 1996, resulting in the
renumbering and augmentation of
certain sections with additional
statutory language. New sections were
added establishing new drinking water
requirements. These modifications are
outlined below.
The Act requires EPA to publish a
National Primary Drinking Water
Regulation (NPDWR) that specifies
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either a maximum contaminant level
(MCL) or treatment technique (Sections
1401(1) and 1412(a)(3)) at the same time
it publishes an MCLG, which is a non-
enforceable health goal. EPA is
authorized to promulgate a NPDWR
"that requires the use of a treatment
technique in lieu of establishing an
MCL," if the Agency finds that "it is not
economically or technologically feasible
to ascertain the level of the
contaminant." EPA's general authority
to set MCLGs and NPDWRs applies 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" (SDWA Section
The 1996 amendments, also require
EPA, when proposing a NPDWR that
includes an MCL or treatment
technique, to publish and seek public
comment on an analysis of health risk
reduction and cost impacts. EPA is
required 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)(Q).
The amendments established a
number of regulatory deadlines,
including schedules for a Stage 1
Disinfection Byproduct Rule (DBPR), an
Interim Enhanced Surface Water
Treatment Rule (IESWTR), a Long Term
Final Enhanced Surface Water
Treatment Rule (LTESWTR), and a Stage
2 DBPR (Section 1412(b)(2)(Q). To
provide additional time for systems
serving fewer than 10,000 people to
comply with the IESWTR provisions
and also ensure these systems
implement Stage 1 DBPR and the
IESWTR provisions simultaneously, the
Agency split the IESWTR into two rules:
the IESWR and the LT1ESWTR. The Act
as amended also requires EPA to
promulgate regulations to "govern" the
recycle of filter backwash within the
treatment process of public utilities
(Section 1412(b)(14)).
Under 1412(b)(4)(E)(ii), EPA must
develop a Small System Technology List
for the LTlFBR. The filtration
technologies listed in the Small System
Compliance Technology List for the
Surface Water Treatment Rule and Total
Coliform Rule (EPA-815-R-98-001,
September 1998) are also the
technologies which would achieve
compliance with the provisions of the
LTlFBR. EPA will develop a separate
list for the LTlFBR as new technologies
become available.
Although the Act permits small
system variances for compliance with a
requirement of a national primary
drinking water regulation which
specifies a maximum contaminant level
or treatment technique, Section
1415(e)(6)(B) of SDWA, excludes
variances for any national primary
drinking water regulation for a
microbial contaminant or an indicator
or treatment technique for a microbial
contaminant. LTlFBR requires
treatment techniques to control
Cryptosporidium (a microbial
contaminant), and as such systems
governed by the LTlFBR are ineligible
for variances.
Finally, as part of the 1996 SDWA
Amendments, recordkeeping
requirements were modified to apply to
every person who is subject to a
requirement of this title 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 the
Administrator may reasonably require
by regulation.
B. Existing Regulations and Stakeholder
Involvement
1. 1979 Total Trihalomethane Rule
In November 1979 (44 FR 68624)
(EPA, 1979) EPA set an interim MCL for
total trihalomethanes (TTHM—the sum
of chloroform, bromoform,
bromodichloromethane,
dibromochloromethane) of 0.10 mg/1 as
an annual average. Compliance is
defined on the basis of a running annual
average of quarterly averages for four
samples taken in the distribution
system. The value for each sample is the
sum of the measured concentrations of
chloroform, bromodichloromethane,
dibromochloromethane and bromoform.
The interim TTHM standard applies
to community water systems using
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. The Stage 1 DBPR (as discussed
later) contains updated TTHM
requirements.
2. Total Coliform Rule
The Total Coliform Rule (TCR) (54 FR
27544, June 29, 1989) (EPA, 1989a)
applies to all public water systems. The
TCR sets compliance with the
Maximum Contaminant Level (MCL) for
total coliforms (TC) as follows. For
systems that collect 40 or more samples
per month, no more than 5 percent of
the samples may be TC-positive; for
those that collect fewer than 40 samples,
no more than one sample may be TC-
positive. If a system has a TC-positive
sample, it must test that sample for the
presence of fecal coliforms or E. coli.
The system must also collect a set of
repeat samples, and analyze for TC (and
fecal coliform or E. coli within 24 hours
of the first TC-positive sample).
In addition, any fecal cohform-
positive repeat sample, B-co/j.-positive
repeat sample, or any total-coliform-
positive repeat sample following a fecal
coliform-positive or E-coli-positive
routine sample constitutes an acute
violation of the MCL for total coliforms.
If a system exceeds the MCL, it must
notify the public using mandatory
language developed by the EPA. The
required monitoring frequency for a
system depends on the number of
people served and ranges from 480
samples per month for the largest
systems to once annually for the
smallest systems. All systems must have
a written plan identifying where
samples are to be collected.
The TCR also requires an on-site
inspection (referred to as a sanitary
survey) every 5 years for each system
that collects fewer than five samples per
month. This requirement is extended to
every 10 years for non-community
systems using only protected and
disinfected ground water.
3. Surface Water Treatment Rule
Under the Surface Water Treatment
Rule (SWTR) (54 FR 27486, June 29,
1989) (EPA, 1989b), EPA set maximum
contaminant level goals of zero for
Giardia lamblia, viruses, and Legionella
and promulgated regulatory
requirements for all 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) Requirements
for maintenance of a disinfectant
residual in the distribution system; (2)
removal and/or inactivation of 3 log
(99.9 percent) for Giardia and 4 log
(99.99 percent) for viruses; (3) combined
filter effluent turbidity performance
standard of 5 nephelometric turbidity
units (NTU) as a maximum and 0.5 NTU
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at the 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 (4)
watershed protection and other
requirements for unfiltered systems.
Systems seeking to avoid filtration were
required to meet avoidance criteria and
obtain avoidance determination by
December 30, 1991, otherwise filtration
must have been provided by June 29,
1993. For systems properly avoiding
filtration, later failures to meet
avoidance criteria triggered a
requirement that filtration be provided
within 18 months.
4. Information Collection Rule
The Information Collection Rule
(ICR), which was promulgated on May
14, 1996 (61 FR 24354) (EPA, 1996)
applied to large public water systems
serving populations of 100,000 or more.
A more limited set of ICR requirements
pertain to ground water systems serving
between 50,000 and 100,000 people.
About 300 PWSs operating 500
treatment plants were involved with the
extensive ICR data collection. Under the
ICR, these PWSs monitored for water
quality factors affecting disinfection
byproduct (DBF) formation and DBFs
within the treatment plant and in the
distribution system on a monthly basis
for 18 months. In addition, PWSs were
required to provide treatment train
schematics, operating data and source
water occurrence data for bacteria,
viruses, and protozoa. Finally, a subset
of PWSs performed treatment studies,
using either granular activated carbon
(GAG) or membrane processes, to
evaluate DBF precursor removal and
control of DBFs. Monitoring for
treatment study applicability began in
September 1996. The remaining
occurrence monitoring began in July
1997 and concluded in December 1998.
The purpose of the ICR was to collect
occurrence and treatment information to
help evaluate the need for possible
changes to the current microbial
requirements and existing microbial
treatment practices, and to help evaluate
the need for future regulation of
disinfectants and disinfection
byproducts (DBFs). The ICR will
provide EPA with additional
information on the national occurrence
in drinking water of (1) chemical
byproducts that form when disinfectants
used for microbial control react with
naturally occurring compounds already
present in source water; and (2) disease-
causing microorganisms, including
Cryptosporidium, Giardia, and viruses.
Analysis of ICR data is not expected to
be completed in the time frame
necessary for inclusion in the LTlFBR,
however if the data is available and has
been quality controlled and peer
reviewed during the necessary time
frame, EPA will consider the datat as it
refines its analysis for the final rule.
The ICR also required PWSs to
provide engineering data on how they
currently control for such contaminants.
The ICR monthly sampling data will
also provide information on the quality
of the recycle waters via monthly
monitoring (for 18 months) of pH,
alkalinity, turbidity, temperature,
calcium and total hardness, TOG, UV254,
bromide, ammonia, and disinfectant
residual (if disinfectant is used). This
data will provide some indication of the
treatability of the water, the extent to
which contaminant concentration
effects may occur, and the potential for
contribution to DBF formation.
However, sampling to determine the
occurrence of pathogens in recycle
waters was not performed.
5. Interim Enhanced Surface Water
Treatment Rule
Public water systems serving 10,000
or more people that use surface water or
ground water under the direct influence
of surface water (GWUDI) are required
to comply with the IESWTR (63 FR
69477, December 16, 1998) (EPA, 1998a)
by December of 2001. The purposes of
the IESWTR are to improve control of
microbial pathogens, specifically the
protozoan Cryptosporidium, and
address risk trade-offs between
pathogens and disinfection byproducts.
Key provisions established by the rule
include: a Maximum Contaminant Level
Goal (MCLG) of zero for
Cryptosporidium; 2-log (99 percent)
Cryptosporidium removal requirements
for systems that filter; strengthened
combined filter effluent turbidity
performance standards of 1.0 NTU as a
maximum and 0.3 NTU at the 95th
percentile monthly, based on 4-hour
monitoring for treatment plants using
conventional treatment or direct
filtration; requirements for individual
filter turbidity monitoring; disinfection
benchmark provisions to assess the level
of microbial protection provided as
facilities take the necessary steps to
comply with new disinfection
byproduct standards; inclusion of
.Cryptosporidium in the definition of
GWUDI and in the watershed control
requirements for unfiltered public water
systems; requirements for covers on new
finished water reservoirs; and sanitary
surveys for all surface water systems
regardless of size.
6. Stage 1 Disinfectants and Disinfection
Byproduct Rule
The Stage 1 DBPR applies to all PWSs
that are community water systems
(CWSs) or nontransient noncommunity
water systems (NTNCWs) that treat their
water with a chemical disinfectant for
either primary or residual treatment. In
addition, certain requirements for
chlorine dioxide apply to transient
noncommunity water systems
(TNCWSs). The Stage 1 DBPR (EPA,
1998c) was published at the same time
as the IESWTR (63 FR 69477, December
16, 1998) (EPA, 1998a). Surface water
and GWUDI systems serving at least
10,000 persons are required to comply
with the Stage 1 Disinfectants and
Disinfection Byproducts Rule by
December 2001. Ground water systems
and surface water and GWUDI systems
serving fewer than 10,000 must comply
with the Stage 1 Disinfectants and
Disinfection Byproducts Rule by
December 2003.
The Stage 1 DBPR finalizes maximum
residual disinfectant level goals
(MRDLGs) for chlorine, chloramines,
and chlorine dioxide; MCLGs for four
trihalomethanes (chloroform,
bromodichloromethane,
dibromochloromethane, and
bromoform), two haloacetic acids
(dichloroacetic acid and trichloroacetic
acid), bromate, and chlorite; and
NPDWRs for three disinfectants
(chlorine, chloramines, and chlorine
dioxide), two groups of organic
disinfection byproducts TTHMs and
HAAS and two inorganic disinfection
byproducts, chlorite and bromate. The
NPDWRs consist of maximum residual
disinfectant levels (MRDLs) or
maximum contaminant levels (MCLs) or
treatment techniques for these
disinfectants and their byproducts. The
NPDWRs also include monitoring,
reporting, and public notification
requirements for these compounds. The
Stage 1 DBPR includes the best available
technologies (BATs) upon which the
MRDLs and MCLs are based. EPA
believes the implementation of the Stage
1 DBPR will reduce the levels of
disinfectants and disinfection
byproducts in drinking water supplies.
The Agency believes the rule will
provide public health protection for an
additional 20 million households that
were not previously covered by drinking
water rules for disinfection byproducts.
' 7. Stakeholder Involvement
EPA conducted two stakeholder
meetings to solicit feedback and
information from the regulated
community and other concerned
stakeholders on issues relating to
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19051
today's proposed rule. The first meeting
was held July 22 and 23,1998 in
Lakewood, Colorado. EPA presented
potential regulatory components for the
LTlFBR. Breakout sessions with
stakeholders were held to generate
feedback on the regulatory provisions
being considered and to solicit feedback
on next steps for rule development and
stakeholder involvement. Additionally,
information was presented summarizing
ongoing research and data gathering
activities regarding the recycle of filter
backwash. The presentations generated
useful discussion and provided
substantial feedback to EPA regarding
technical issues, stakeholder concerns,
and possible regulatory options (EPA
1999k), The second stakeholder meeting
was held in Dallas, Texas on March 3
and 4,1999. EPA presented new
analyses, summaries of current research,
and revised regulatory options and data
collected since the July stakeholder
meeting. Regional perspectives on
turbidity and disinfection benchmarking
components were also discussed with
presentations from EPA Region VI and
the Texas Natural Resources
Conservation Commission. Four break-
out sessions were extremely useful and
generated a wide range of information,
issues, and technical input from a
diverse group of stakeholders (EPA
1999J).
The Agency utilized the feedback
received during these two stakeholder
meetings in developing today's
proposed rule. EPA also mailed a draft
version of the preamble for today's
proposed rule to the attendees of these
meetings. Several of the options which
are presented today represent
modifications suggested by
stakeholders.
II. Public Health Risk
The purpose of this section, is to
discuss the health risk associated with
pathogens, particularly
Cryptosporidium, in surface waters and
GVVUDI. More detailed information
about such pathogens and other
contaminants of concern may be found
in an EPA criteria document for Giardia
(EPA 1998d), three EPA criteria
documents for viruses (EPA, 1985;
1999a; 1999b), the Cryptosporidium and
Giardia Occurrence Assessment for the
Interim Enhanced Surface Water
Treatment Rule (EPA, 1998b) and the
LTlFBR Occurrence and Assessment.
Document (EPA 1999c). EPA requests
comment on today's proposed rule, the
information supporting the proposal,
and the potential impact of proposed
regulatory provisions on public health
risk.
A. Introduction
In 1990, EPA's Science Advisory
Board (SAB), an independent panel of
experts established by Congress, cited
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 (EPA/SAB, 1990).
Information on the number of
waterborne disease outbreaks from the
U.S. Centers for Disease Control and
Prevention (CDC) underscores this
concern. CDC indicates that, between
1980 and 1996, 401 waterborne disease
outbreaks were reported, with over
750,000 associated cases of disease.
During this period, a number of agents
were implicated as the cause, including
protozoa, viruses and bacteria.
Waterborne disease caused by
Cryptosporidium is of particular
concern, as it is difficult to inactivate
Cryptosporidium oocysts with standard
disinfection practices (unlike pathogens
such as viruses and bacteria), and there
is currently no therapeutic treatment for
cryptosporidiosis (unlike giardiasis).
Because Cryptosporidium is not
generally inactivated in systems using
standard disinfection practices, the
control of Cryptosporidium is
dependent on physical removal
processes (e.g., filtration).
The filter effluent turbidity limits
specified under the SWTR were created
to remove large parasite cysts such as
Giardia and did not specifically control
for smaller Cryptosporidium oocysts. In
addition, filter backwash water
recycling practices such as adding
recycled water to the treatment train
after primary coagulant addition may
overwhelm the plant and harm efforts to
control Giardia lamblia,
Cryptosporidium, and emerging
pathogens. Despite filtration and
disinfection, Cryptosporidium oocysts
have been found in filtered drinking
water (LeChevallier, et al., 1991a; EPA,
1999c), and many of the individuals
affected by waterborne disease
outbreaks caused by Cryptosporidium
were served by filtered surface water
supplies (Solo-Gabriele and Neumeister,
1996). Surface water systems that filter
and disinfect may still be vulnerable to
Cryptosporidium, depending on the
source water quality and treatment
effectiveness. EPA believes that today's
proposal, however, will ensure that
drinking water treatment is operating
efficiently to control Cryptosporidium
(see Sections IV.A and IV.D) and other
microbiological contaminants of
concern (e.g., Giardia}.
In order to assess the public health
risk associated with consumption of
surface water or GWUDI from PWSs,
EPA has evaluated information and
conducted analysis in four important
areas discussed in the following
paragraphs. These areas are: (l) The
health effects of cryptosporidiosis; (2)
cryptosporidiosis waterborne disease
outbreak data; (3) Cryptosporidium
occurrence data from raw surface water,
raw GWUDI, finished water, and recycle
stream studies; and (4) an assessment of
the current baseline surface water
treatment required by existing
regulations.
B. Health Effects of Cryptosporidiosis
and Sources and Transmission of
Cryptosporidium
Waterborne diseases are usually acute
(i.e., sudden onset and typically lasting
a short time in healthy people), and
most waterborne pathogens cause
gastrointestinal illness, with diarrhea,
abdominal discomfort, nausea,
vomiting, and/or other symptoms. Some
waterborne pathogens cause or are
associated with more serious disorders
such as hepatitis, gastric cancer, peptic
ulcers, myocarditis, swollen lymph
glands, meningitis, encephalitis, and
many other diseases. Cryptosporidiosis
is a protozoal infection that usually
causes 7-14 days of diarrhea with
possibly a low-grade fever, nausea, and
abdominal cramps in healthy
individuals (Juranek, 1995). Unlike
giardiasis for which effective antibiotic
therapy is available, an antibiotic
treatment for cryptosporidiosis does not
exist (Framm and Soave, 1997).
There are several species of
Cryptosporidium which have been
identified, including C. baileyi and C.
meleagridis (bird host); C. muris (mouse
host); C. nasorum (fish host), C. parvum
(mammalian host), and C. serpentis
(snake host). Cryptosporidium parvum
was first recognized as a human
pathogen in 1976 (Juranek, 1995).
Recently, both the human and cattle
types of C. parvum have been found in
healthy individuals, and these types, C.
felis, and a dog type have been found in
immunocompromised individuals
(Pieniazek et al., 1999). Transmission of
cryptosporidiosis often occurs through
the ingestion of infective
Cryptosporidium oocysts from feces-
contaminated food or water, but may
also result from direct or indirect
contact with infected persons or
mammals (Casemore, 1990; Cordell and
Addiss, 1994). Dupont, et. al., 1995,
found through a human feeding study
that a low dose of C. parvum is
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Federal Register/Vol. 65, No. 69/Monday, April 10, 2000/Proposed Rules
sufficient to cause infection in healthy
adults (Dupont et. al., 1995). Animal
agriculture as a nonpoint source of C.
parvum has been implicated as the
source of contamination for the 1993
outbreak in Milwaukee, Wisconsin, the
largest outbreak of waterborne disease
in the history of the United States
(Walker et al., 1998). Other sources of C.
parvum include discharges from
municipal wastewater treatment
facilities and drainage from
slaughterhouses. In addition, rainfall
appears to increase the concentration of
Cryptosporidium in surface water,
documented in a study by Atherholt, et
al. (1998).
There is evidence that an immune
response to Cryptosporidium exists, but
the degree and duration of this
immunity is not well characterized
(Payer and Ungar, 1986). Recent work
conducted by Chappell, et al. (1999)
indicates that individuals with evidence
of prior exposure to Cryptosporidium
parvum have demonstrated immunity to
low doses of oocysts (approximately 500
oocysts). The investigators found the 50
percent infectious dose for previously
exposed individuals (possessing a pre-
existing blood serum antibody) to be
1,880 oocysts compared to 132 oocysts
for individuals without prior exposure,
and individuals with prior exposure
who became infected shed fewer
oocysts. Because of this type of immune
response, symptomatic infection in
communities exposed to chronic low
levels of oocysts will primarily be
observed in newcomers (e.g., visitors, ,
young children) (Frost et al., 1997;
Okhuysen et al., 1998).
Sensitive populations are more likely
to become infected and ill, and
gastrointestinal illness among this
population may be chronic. These
sensitive populations include children,
especially the yery young; the elderly;
pregnant women; and the
immunocompromised (Gerba et al.,
1996; Payer and Ungar, 1986; EPA
1998e). This sensitive segment
represents almost 20 percent of the
population in the U.S. (Gerba et al.,
1996). EPA is particularly concerned
about the exposure of severely
immunocompromised persons to
Cryptosporidium in drinking water,
because the severity and duration of
illness is often greater in
immunocompromised persons than in
healthy individuals, and it may be fatal
among this population. For instance, a
follow-up study of the 1993 Milwaukee,
Wisconsin, waterborne disease outbreak
reported that at least 50
CryptosporiA'um-associated deaths
occurred among the severely
immunocompromised (Hoxie et al.,
1997).
Cases of illness from
cryptosporidiosis were rarely reported
until 1982, when the disease became
prevalent due to the AIDS epidemic
(Current, 1983). As laboratory diagnostic
techniques improved during subsequent
years, outbreaks among
immunocompetent persons were
recognized as well. Over the last several
years there have been a number of
documented waterborne
cryptosporidiosis outbreaks in the U.S.,
United Kingdom, Canada and other
countries (Rose, 1997, Craun et al.,
1998).
C. Waterborne Disease Outbreaks in the
United States
The occurrence of outbreaks of
waterborne gastrointestinal infections,
including cryptosporidiosis, may be
much greater than suggested by reported
surveillance data (Craun and Calderon
1996). The CDC-EPA, and the Council
of State and Territorial Epidemiologists
have maintained a collaborative
surveillance program for collection and
periodic reporting of data on waterborne
disease outbreaks since 1971. The CDC
database and biennial CDC-EPA
surveillance summaries include data
reported voluntarily by the States on the
incidence and prevalence of waterborne
illnesses. However, the following
information demonstrates why the
reported surveillance data may under-
report actual outbreaks.
The U.S. National Research Council
strongly suggests that the number of
identified and reported outbreaks in the
CDC database (both for surface and
ground waters) represents a small
percentage of actual waterborne disease
outbreaks National Research Council,
1997; Bennett et al., 1987). In practice,
most waterborne outbreaks in
community water systems are not
recognized until a sizable proportion of
the population is ill (Perz et al.)
Healthy adults with cryptosporidiosis
may not suffer severe symptoms from
the disease; therefore, infected
individuals may not seek medical
assistance, and their cases are
subsequently not reported. Even if
infected individuals consult a
physician, Cryptosporidium may not be
identified by routine diagnostic tests for
gastroenteritis and, therefore, tends to
be under-reported in the general
population (Juranek 1995). Such
obstacles to outbreak reporting indicate
that the incidence of disease and
outbreaks of cryptosporidiosis may be
much higher than officially reported by
the CDC.
The CDC database is based upon
responses to a voluntary and
confidential survey that is completed by
State and local public health officials.
CDC defines a waterborne disease
outbreak as occurring when at least two
persons experience a similar illness
after ingesting water (Kramer et al.,
1996). Cryptosporidiosis water system
outbreak data from the CDC database
appear in Table II.l and Table II.2.
Table II.l illustrates the reported
number of waterborne disease outbreaks
in U.S. community, noncommunity, and
individual drinking water systems
between 1971 and 1996. According to
the CDC-EPA database, a total of 652
outbreaks and 572,829 cases of illnesses
were reported between 1971 and 1996
(see Table II-l). The total number of
outbreaks reported includes outbreaks
resulting from protozoan contamination,
virus contamination, bacterial
contamination, chemical contamination,
and unknown factors.
TABLE 11.1.—COMPARISON OF OUTBREAKS AND OUTBREAK-RELATED ILLNESSES FROM GROUND WATER AND SURFACE
WATER FOR THE PERIOD 1971-19961
Water source
Ground
Surface
Other
Total out-
breaks 2
371 (57%)
223 (34%)
58 (9%)
Cases of2
illnesses
90 815
(16%).
471 375
(82%).
10639
(2%).
Outbreaks in
CWSs
113
148
30
Outbreaks in
NCWSs
258
43
19
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19053
TABLE II. 1. — COMPARISON
OF OUTBREAKS AND OUTBREAK-RELATED ILLNESSES FROM GROUND WATER AND SURFACE
WATER FOR THE PERIOD 1971-1996 1 — Continued
Water source
All Systems3
Total out-
breaks2
652
(100%).
Cases of2
illnesses
572,829
(100%).
Outbreaks in
CWSs
291
Outbreaks in
NCWSs
320
'Craun and Calderon, 1994, CDC, 1998.
2 Includes outbreaks in CWSs + NCWSs + Private wells.
Epidemiological investigations of
outbreaks in populations served by
filtered systems have shown that
treatment deficiencies have resulted in
the plants' failure to remove
contamination from the water.
Sometimes operational deficiencies
have been discovered only during post-
outbreak investigations. Rose (1997)
identified the following types of
environmental and operating conditions
commonly present in filtered surface
water systems at the time
cryptosporidiosis outbreaks have
occurred:
• Improperly-installed, -operated,
-maintained, or -interpreted monitoring
• Equipment (e.g., turbidimeters);
• Inoperable flocculates, chemical
injectors, or filters;
• Inadequate personnel response to
failures of primary monitoring
equipment;
• Filter backwash recycle;
• High concentrations of oocysts in
source water with no mitigative barrier;
• Flushing of oocysts (by heavy rain
or snow melt) from land surfaces
upstream of the plant intakes; and
• Altered or suboptimal filtration
during periods of high turbidity, with
turbidity spikes detected in finished
water.
From 1984 to 1994, there have been
19 reported outbreaks of
cryptosporidiosis in the U.S. (Craun et
al., 1998). As mentioned previously, C.
parvum was not identified as a human
pathogen until 1976. Furthermore,
cryptosporidiosis outbreaks were not
reported in the U.S. prior to 1984. Ten
of these cryptosporidiosis outbreaks
have been documented in CWSs,
NCWSs, and a private water system
(Moore et al., 1993; Kramer et al., 1996;
Levy et al., 1998; ; Craun et al., 1998).
The remaining nine outbreaks were
associated with recreational activities
(Craun et al., 1998). The
cryptosporidiosis outbreaks in U.S.
drinking water systems are presented in
Table II.2.
TABLE 11.2.—CRYPTOSPORIDIOSIS OUTBREAKS IN U.S. DRINKING WATER SYSTEMS
Year
1984
1987 ,
1991
1992
1992
1993
1993
1993 . . .
1994
1994
Location and CWS,
NCWS, or private
Braun Station TX
CWS.
Carrollton, GA, CWS
Berks County PA
NCWS.
Medford (Jackson
County), OR. CWS.
Talent OR CWS . .
Milwaukee Wl, CWS
Yakima, WA private
Cook County MN
NCWS.
Clark County, NV,
CWS.
Walla Walla WA
CWS.
Cases of
illness
(estimated)
117(2000)
(13,000)
(551)
(3,000; combined
total for Jackson
County and Talent,
below).
see Medford OR ..
(403,000)
7
27
1 03; many confirmed
for
cryptosporidiosis
were HIV positive.
134
Source water
Well ...
River
Well
Spring/River
Spring/River . .
Lake
Well
Lake
River/Lake
Well
Treatment
Chlorination
Conventional filtra-
tion/chlorination; in-
adequate
backwashing of
some filters.
Chlorination
Chlorination/package
filtration plant.
Chlorination/package
filtration plant.
Conventional filtration
N/A
Filtered chlorinated .
Prechlorination, filtra-
tion and post-filtra-
tion Chlorination.
None reported
Suspected cause
Sewage-contami-
nated well.
Treatment defi-
ciencies.
Ground water under
the influence of
surface water.
Source not identified.
Treatment defi-
ciencies.
High source water
contamination and
treatment defi-
ciencies.
Ground water under
the influence of
surface water.
Possible sewage
backflow from toi-
let/septic tank.
Source not identified.
Sewage contamina-
tion.
Craun, etal., 1998.
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Federal Register/Vol. 65, No. 69/Monday, April 10, 2000/Proposed Rules
Six of the ten cryptosporidiosis
outbreaks reported in Table II.2
originated from surface water or
possibly GWUDI supplied by public
drinking water systems serving fewer
than 10,000 persons. The first outbreak
(117 known cases, 2,000 estimated cases
of illness), in Braun Station, Texas in
1984, was caused by sewage leaking into
a ground water well suspected to be
under the influence of surface water. A
second outbreak in Pennsylvania in
1991 (551 estimated cases of illness),
occurred at a well also under the
influence of surface water. The third
and fourth (multi-episodic) outbreaks
took place in Jackson County, Oregon in
1992 (3,000 estimated cases of illness)
and were linked to treatment
deficiencies in the Talent, OR surface
water system. A fifth outbreak (27 cases
of illness) in Minnesota, in 1993,
occurred at a resort supplied by lake
water. Finally, a sixth outbreak (134
cases of illness) in Washington in 1994,
occurred due to sewage-contaminated
wells at a CWS.
Three of the ten outbreaks (Carollton,
GA (1987); Talent, OR (1992);
Milwaukee, WI (1993)) were caused by
water supplied by water treatment
plants where the recycle of filter
backwash was implicated as a possible
cause of the outbreak. In total, the nine
outbreaks which have taken place in
PWSs have caused an estimated 419,939
cases of illness. These outbreaks
illustrate that when treatment in place
is not operating optimally or when
source water is highly contaminated,
Cryptosporidium may enter the finished
drinking water and infect drinking
water consumers, ultimately resulting in
waterborne disease outbreaks.
D. Source Wafer Occurrence Studies
Cryptosporidium is common in the
environment (Rose, 1988; LeChevallier
et al., 1991b). Runoff from unprotected
watersheds allows the transport of these
microorganisms from sources of oocysts
(e.g., untreated wastewater, agricultural
runoff) to water bodies used as intake
sites for drinking water treatment
plants. If treatment operates
inefficiently, oocysts may enter the
finished water at levels of public health
concern. A particular public health
challenge is that simply increasing
existing disinfection levels above those
most commonly practiced for standard
disinfectants (i.e., chlorine or
chloramines) in the U.S. today does not
appear to be an effective strategy for
controlling Cryptosporidium.
Cryptosporidium oocysts have been
detected in wastewater, pristine surface
water, surface water receiving
agricultural runoff or contaminated by
sewage, ground water under the direct
influence of surface water (GWUDI),
water for recreational use, and drinking
water (Rose 1997, Soave 1995). Over 25
environmental surveys have reported
Cryptosporidium source water
occurrence data from surface water or
GWUDI (presented in Tables II.3 and
II.4), which typically involved the
collection of a few water samples from
a number of sampling locations having
different characteristics (e.g., polluted
vs. pristine; lakes or reservoirs vs.
rivers). Results are presented as oocysts
per 100 liters, unless otherwise marked.
Each of the studies cited in Tables II. 3
and II.4 presents Cryptosporidium
source water occurrence information,
including (where possible): (1) The
number of samples collected; (2) the
number of samples positive; and (3)
both the means and ranges for the
concentrations of Cryptosporidium
detected (where available). However,
the immunofluorescence assay (IFA)
method and other Cryptosporidium
detection methods are inaccurate and
lack adequate precision. Current
methods do not indicate the species of
Cryptosporidium identified or whether
the oocysts detected are viable or
infectious (Frey et al., 1997). The
methods for detecting Cryptosporidium
were modeled from Giardia methods,
therefore recovery of Cryptosporidium is
deficient primarily because
Cryptosporidium oocysts are more
difficult to capture due to their size
(Cryptosporidium oocysts are 4—6|i6=Sm;
Giardia cysts are 8—12|i9Sm). In
addition, it is a challenge to recover
Cryptosporidium oocysts from the filters
when they are concentrated, due to the
adhesive character of the organisms.
Other potential limitations to the
protozoan detection methods include:
(1) Filters used to concentrate the water
samples are easily clogged by debris
from the water sample; (2) interference
occurs between debris or particulates
that fluoresce due to cross reactivity of
antibodies, which results in false
positive identifications; (3) it is difficult
to view the structure of oocysts on the
membrane filter or slide, resulting in
false negative determinations; and (4)
most methods require an advanced level
of skill to be performed accurately.
Despite these limitations, the
occurrence information generated from
these studies demonstrates that
Cryptosporidium occurs in source
waters. The source waters for which
EPA has compiled information include
rivers, reservoirs, lakes, streams, raw
water intakes, springs, wells under the
influence of surface water and
infiltration galleries. The most
comprehensive study in scope and
national representation (LeChevallier
and Norton, 1995) will be described in
further detail following Tables II.3 and
II.4.
TABLE 11.3.—SUMMARY OF SURFACE WATER SURVEY AND MONITORING DATA FOR CRYPTOSPORIDIUM OOCYSTS
Sample source
Rivers .
River
Reservoirs/rivers (polluted)
Reservoir (pristine)
Impacted river
Lake
Stream
Raw water
River (pristine)
River (polluted)
Lake/reservoir (pristine)
Lake/reservoir (polluted)
Number of
samples (n)
25
6
6
6
11
20
19
85
59
38
34
24
Samples
positive
for
Cryptosporidium
(percent)"
100
100
100
83
100
71
74
87
32
74
53
58
Range of oocyst
cone.
(oocysts/100L)
200-1 1 200
200-580 000
19-300
1-13
200-11 200b
0-2200
0-24 000
7-48 400
NR
<0 1_4400b
NR
<0.1-380»
Mean
(oocysts/100L)
2510
192000(a)
99(a)
2(a)
2 500(q)
58(q)
109(g)
270(g) detect-
able.
29(q)
66(q)
93(q)
103(q)
Reference
Ongerth and Stibbs 1 987
Madore et al 1987
Rose 1988.
Rose 1988
Rose et al 1 988ab
Rose et al 1988bb
Rose et al 1988bb
LeChevallier et al 1991c
Rose et al 1991
Rose et al 1 991
Rose et al 1991
Rose et al. 1991.
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19055
TABLE 11.3.—SUMMARY OF SURFACE WATER SURVEY AND MONITORING DATA FOR CRYPTOSPORIDIUM OOCYSTS—
Continued
Sample source
River (all samples) .
(subset of all).
of all).
eslcd area (subset of all).
tural activities (subset of all).
bkfily).
bldity).
Lakes
Finished water
River/take
River 1
River 2
Dairy farm stream
Reservoir Inlets
Source water .
River 1
Raw water intakes
Raw Water
DE River Winter
DE River, Spring
DE River. Fall
Number of
samples (n)
36
g
6
6
6
56
33
37
10
10
10
179
210
262
262
147
15
15
13
60
60
72
NR
20
21
24
22
24
NR
148
NR
100 plants
18
18
18
18
Samples
positive
for
Cryptosporidium
(percent)"
97
81
100
100
100
45
48
51
100
70
70
6
6
13
52
20
73
80
77
5
12
40
24
35
19
63
82
63
37_52d
25
NR
77
NR
NR
NR
NR
Range of oocyst
cone.
(oocysts/100L)
15-45 (pristine)
1000-6,350
(agricultural).
15-42
46-697
54-360
330-6 350
NR
NR
NR
82-7 190
42-510
77-870
0-2,240
0-2,000
0.29-57
6.5-6,510
30-980
0-2,230
0-1,470
0-1,110
0.7-24
1.2-107
20-280
1-5,390"
0-41,700
0-650
0-1,470
0-2,300
0-2 200
15-43 (maxi-
ma)'1.
0.04-18
40-400
0.5-117
NR
NR
NR
NR
Mean
(oocysts/100L)
20 (pristine)
1 ,830 (agricul-
tural).
24(q)
162(q)
107(q)
1 072(q) . .
NR
NR
NR
480
250
250
3.3 (median)
7 (median)
33 (detectable)
240 (detectable)
200
1 88 (a) all sam-
ples 43 (g)
detected.
147 (a) all sam-
ples 61 (g)
detected.
126 (a) all sam-
ples 55 (g)
detected.
1.9(g) 1.6 (me-
dian).
6.1 (g) 60 (me-
dian).
24(g)
740(a)=71(g)= ...
NR
NR
58(g)
42(g)
31(g)
0 8-1 4J
0.3
NR
3(g)
70 per 500L(g) ..
100 per500L(g)
30 per 500L(g) ..
20 per 500L(g) ..
Reference
Hansen and Ongerth 1991.
Hansen and Ongerth 1991.
Hansen and Ongerth 1991.
Hansen and Ongerth 1991.
Hansen and Ongerth 1991.
Consonery et al. 1 992.
Consonery et al. 1992.
Consonery et al. 1992.
LeChevallier and Norton 1 992.
LeChevallier and Norton 1 992.
LeChevallier and Norton 1992.
Archer et al. 1995.
Archer et al. 1995.
LeChevallier and Norton 1995.
LeChevallier and Norton 1995.
LeChevallier et al. 1995.
States etal. 1995.
States etal. 1995.
States et al. 1 995.
LeChevallier et al. 1997b.
LeChevallier et al. 1997b.
LeChevallier et al. 1997a.
Swertfeger et al. 1997.
Stewart etal. 1997.
Stewart etal. 1997.
States etal. 1997.
States etal. 1997.
States et al. 1997.
Okun et al. 1997.
Consonery et al. 1997.
Swiger et al. 1999.
McTigue, etal. 1998.
Atherholt, etal. 1998.
Atherholt, et al. 1998.
Atherholt, etal. 1998.
Atherholt, etal. 1998.
"Rounded to nearest percent.
>>As cited in Lisle and Rose 1995.
« Based on presumptive oocyst count
11 Combined monitoring results for multiple sites in large urban water supply.
«As cited in States et al. 1997.
(a) = arithmetic average.
(g) = geometric average.
NR = not reported, NA = not applicable.
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Federal Register/Vol. 65, No. 69/Monday, April 10, 2000/Proposed Rules
TABLE H.4.—SUMMARY OF U.S. GWUDI MONITORING DATA FOR CRYPTOSPORIDIUM OOCYSTS
Sample source
Well
Vertical wells (subcategory of above
ground water sources).
Springs (subcategory of above
ground water sources).
Infiltration galleries (subcategory of
above ground water sources).
Horizontal wells (subcategory of
above ground water sources).
Ground water
Springs
Wells
Vertical well Lemont Well #4 (Center
Co., PA, Aug. 1992).
Number of
samples (n)
17 (6 wells) ..
199 sitesb
149 sitesb
35 sitesb
4 sitesb
11 sitesb
17
18
7 (4 springs)
5 sites
6
Samples posi-
tive for
Cryptosporidium
oocysts (per-
cent)
(1 sample)
11b
5b
20b
50b
45b
41.2
5.6
57b
100
667
Range of
positive val-
ues (oocysts/
100L)
.085L
0 002-0 45d
NR
NR
NR
NR
NR
.13
0.25-10
0.26-3
NR
Mean
(oocysts/
100L)"
NA
NR
NR
NR
NR
NR
NR
.13
4
0.9
NR
Reference
Archer et al. 1995.
Hancock et al. 1998i
Hancock et al. 1998.
Hancock et al. 1998.
Hancock et al. 1998.
Hancock et al. 1998.
Rosen et al., 1996.
Rose et al. 1991.
Rose et al. 1991.
SAIC, 1997C
Lee, 1993.
a Geometric mean reported unless otherwise indicated.
bData are presented as the percentage of positive sites.
cData included are confirmed positive samples not reported in Hancock, 1998.
NA = not applicable.
NR = not reported.
The LeChevallier and Norton (1995)
study collected the most samples and
repeat samples from the largest number
of surface water plants nationally.
LeChevallier and Norton conducted the
study to determine the level of
Cryptosporidium in surface water
supplies and plant effluent water. In
total, surface water sources for 72
treatment plants in 15 States and 2
Canadian provinces were sampled.
Sixty-seven surface water locations were
examined. The generated data set
covered a two-year monitoring period
(March, 1991 to January, 1993) which
was combined with a previous set of
data (October, 1988 to June, 1990)
collected from most of the same set of
systems to create a database containing
five samples (IFA) per site or more for
94 percent of the 67 systems sampled.
Cryptosporidium oocysts were detected
in 135 (51.5 percent) of the 262 raw
water samples collected between March
1991 and January 1993, while 87
percent of the 85 samples were positive
during the survey period from October,
1988 to June, 1990. The geometric mean
of detectable Cryptosporidium -was 240
oocysts/lOOL, with a range from 6.5 to
6510 oocysts/lOOL. When the 1991-
1993 results (n=262) were combined
with the previous results (n=85),
Cryptosporidium was detected in 60.2
percent of the samples. The authors
hypothesize the origin of the decrease in
detections in the second round of
sampling to be most probably linked to
fluctuating or declining source water
concentrations of Cryptosporidium
oocysts from the first reporting period to
the second.
LeChevallier and Norton (1995) also
detected Cryptosporidium oocysts in 35
of 262 plant effluent samples (13.4
percent) analyzed between 1991 and
1993. When detected, the oocyst levels
averaged 3.3 oocysts/100 L (range = 0.29
to 57 oocysts/100 L). A summary of
occurrence data for all samples in
filtered effluents for the years 1988 to
1993 showed that 32 of the water
treatment plants (45 percent) were
consistently negative for
Cryptosporidium; 24 plants (34 percent)
were positive once; and 15 plants (21
percent) were positive for
Cryptosporidium two or more times
between 1988 to 1993. Forty-four of the
plants (62 percent) were positive for
Giardia, Cryptosporidium, or both at
one time or another (LeChevallier and
Norton 1995).
The oocyst recoveries and densities
reported by LeChevallier and Norton
(1995) are comparable to the results of
another survey of treated, untreated,
protected (pristine) and feces-
contaminated (polluted) water supplies
(Rose et al. 1991). Six of thirty-six
samples (17 percent) taken from potable
drinking water were positive for
Cryptosporidium, and concentrations in
these waters ranged from .5 to 1.7
oocysts/lOOL. In addition, a total of 188
surface water samples were analyzed
from rivers, lakes, or springs in 17
States. The majority of surface water
samples were obtained from Arizona,
California, and Utah (126 samples in
all), with others from eastern States (28
samples), northwestern States (14
samples), southern States (13 samples),
midwestern States (6 samples), and
Hawaii (1 sample). Arithmetic average
oocyst concentrations ranged from less
than 1 to 4,400 oocysts/100 L,
depending on the type of water
analyzed. Cryptosporidium oocysts were
found in 55 percent of the surface water
samples at an average concentration of
43 oocysts/100 L.
The LeChevallier and Norton (1995)
study collected the most samples and
repeat samples from the most surface
water plants on a national level.
Therefore, the data from this study were
analyzed by EPA (EPA, 1998n) to
generate a distribution of source water
occurrence, presented in Table II. 5.
TABLE 11.5.—BASELINE EXPECTED NA-
TIONAL SOURCE WATER
CRYPTOSPORIDIUM DISTRIBUTIONS
Percentile
25
50
75
90
95
Mean
Standard Deviation ....
Source
water
concentration
(oocysts/100L)
103
231
516
1064
1641
470
841
Although limited by the small number
of samples per site (one to sixteen
samples; most sites were sampled five
times), the mean concentration at the 69
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19057
sites from the eastern and central U.S.
seems to be represented by a lognormal
distribution.
In addition to the source water data,
several studies have detected
Cryptosporidium oocysts in finished
water. The results of these studies have
been compiled in Table II.6.
TABLE 11.6.—SUMMARY OF U.S. FINISHED WATER MONITORING DATA FOR CRYPTOSPORIDIUM OOCYSTS
Sample source
Filleted water .....
Finished water
Finished water (clearwell)
Finished water (filter effluents)
Site 1 — Filter effluent
Site 2 — Filter effluent
Site 3 — Filter effluent
Finished water
Finished water
Finished water
Finished water
Number of
samples (n)
82
6
262
14
118
10
10
10
1 237
87
24
155
100
Samples posi-
tive for
Cryptosporidium
(percent)
27
33
13
14
26
70
10
10
7
10
"8
***13
2.5
15
Range of
oocyst cone.
(oocysts/
100L)
0.1^8
0 1-1 7
0.29-57
NR
NR
•\-4
0.5
2
NR
0-420
0-0.6
0.02-0.8
0.04-0.08 ....
Mean
i (oocysts/
100L)
i.5
02
33 (detect-
able).
NR
NR
NR
NA
NA
NR
NR
0.5 (g)
0.2
0.08 (g)
Reference
LeChevallier et al. 1991 a.
LeChevallier et al 1 992
LeChevallier and Norton 1995.
Consonery et al. 1992.
Consonery et al. 1992.
LeChevallier and Norton 1992.
LeChevallier and Norton 1 992.
LeChevallier and Norton 1992.
Rosen et al. 1996.
Stewart et al. 1997a.
States etal. 1997.
Consonery et al. 1997.
McTigue, etal. 1998.
•Plants
"Confirmed
•"Presumed
These studies show that despite some
treatment in place, Cryptosporidium
may still pass through the treatment
plant and into finished water.
In general, oocysts are detected more
frequently and in higher concentrations
In rivers and streams than in lakes and
reservoirs (LeChevallier et al., 1991b;
Rose et al., 1988a,b). Madore et al.
(1987) found high concentrations of
oocysts in a river affected by
agricultural runoff (5800 oocysts/L).
Such concentrations are especially
significant if the contaminant removal
process (e.g., sedimentation, filtration)
of the treatment plant is not operating
effectively. Oocysts may pass through to
the finished water, as LeChevallier and
Norton (1995) and several other
researchers also found, and infect
drinking water consumers.
E. Filter Backwash and Other Process
Streams: Occurrence and Impact
Studies
Pathogenic microorganisms are
removed during the sedimentation and/
or filtration processes in a water
treatment plant. Recycle streams
generated during treatment, such as
spent filter backwash water,
sedimentation basin sludge, or thickener
supernatant are often returned to the
treatment train. These recycle streams,
therefore, may contain high
concentrations of pathogens, including
chlorine-resistant Cryptosporidium
oocysts. Recycle can degrade the
treatment process, especially when
entering the treatment train after the
rapid mix stage, by causing a chemical
imbalance, hydraulic surge and
potentially overwhelming the plant's
filtration capacity with a large
concentration of pathogens. High oocyst
concentrations found in recycle waters
can increase the risk of pathogens
passing through the treatment plant into
finished water.
AWWA has compiled issue papers on
each of the following recycle streams:
Spent filter backwash water,
sedimentation basin solids, combined
thickener supernatant, ion-exchange
regenerate, membrane concentrate,
lagoon decant, mechanical dewatering
device concentrate, monofill leachate,
sludge drying bed leachate, and small-
volume streams (e.g., floor, roof, lab
drains) (Environmental Engineering &
Technology, 1999). In addition, EPA
compiled existing occurrence data on
Cryptosporidium in recycle streams.
Through these efforts, Cryptosporidium
occurrence data has been found for
three types of recycle streams: Spent
filter backwash water, sedimentation
basin solids, and thickener supernatant.
Nine studies have reported the
occurrence of Gryptosporidium for these
process streams. Each study's scope and
results are presented in Table II.7, and
brief narratives on each major study
follow the table. Note that the results of
the studies, if not presented in the
published report as oocysts/lOOL, have
been converted into oocysts/lOOL.
TABLE 11.7.—CRYPTOSPORIDIUM OCCURRENCE IN FILTER BACKWASH AND OTHER RECYCLE STREAMS
Name/location of study
Drinking water treat-
ment facilities.
Number of
samples (n)
2
Type of sample
backflush waters from
rapid sand filters.
Cyst/oocyst concentration
sample 1: 26,000 oocysts/gal
(calc. as 686,900 oocysts/
100L).
sample 2: 92,000 oocysts/gal
(calc as 2,430,600 oocysts/
100L)
Number of
treatment
plants sampled
2
Reference
Rose etal. 1986.
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Federal Register/Vol. 65, No. 69/Monday, April 10, 2000/Proposed Rules
TABLE 11.7.—CRYPTOSPORIDIUM OCCURRENCE IN FILTER BACKWASH AND OTHER RECYCLE STREAMS—Continued
Name/location of study
Thames, U.K.,
Potable water supplies
in 17 States.
Name/location not re-
ported.
Bangor Water Treat-
ment Plant (PA).
Round 2: 1 (8-hour
composite).
Moshannon Valley
Water Treatment
Plant.
Plant "C"
Pittsburgh Drinking
Water Treatment
Plant.
"Plant Number 3"
"Plant C" (see Karanis
et al. 1996).
"Plant A" ;
Number of
samples (n)
not reported .
not reported ....
not reported
Round 1: 1 (8-
hour com-
posite).
raw water
filter backwash
supernatant re-
cycle
Round 1' 1 (8-
hour com-
posite).
Round 2: 1 (8-
hour com-
posite).
1 1 samples
using contin-
uous flow
centrifuga-
tion;.
24 (two years
of monthly
samples).
riot reported
12
50
1
Type of sample
backwash water from
rapid sand filter.
filter backwash from
rapid sand filters (10
to 40 L sample vol.).
raw water
initial backwash water
raw water
filter backwash
supernatant recycle 6
oocysts/1 OOL.
140 oocysts/1 OOL
raw water
spent backwash
supernatant recycle
sludge 13 oocysts/
100L.
raw water
supernatant recycle
39 samples using car-
tridge filters.
filter backwash
raw water
spent backwash
raw water
backwash water from
rapid sand filters.
rapid sand filter (sam-
ple taken 10 min.
after start of
backwashing).
Cyst/oocyst concentration
Over 1 000 000 oocysts/1 OOL
in backwash water on 2/1 9/
89.
100,000 oocysts/1 OOL in su-
pernatant from settlement
tanks during the next few
days
217 oocysts/ 100 L (geometric
mean).
7 to 108 oocysts/1 OOL
detected at levels 57 to 61
times higher than in the raw
water.
902 oocysts/1 OOL
850 oocysts/1 OOL
16 613 oocysts/1 OOL
20 oocysts/1 OOL
backwash water from rapid
sand filters; samples col-
lected from sedimentation
basins during sedimentation
phase of backwash water at
depths of 1 , 2, 3, and 3.3 m.
328 oocysts/ 100 L (geometric
mean); (38 percent occur-
rence rate).
140 oocysts/1 OOL
avg 23 2 oocysts/1 OOL (max
109 oocysts/1 OOL) in 8 of 12
samples.
150 oocysts/1 OOL
Number of
treatment
plants sampled
1
not reported ....
not reported
141 oocysts/
100L 1
100L. 1
82 oocysts/
100L
420 oocysts/
100L. 1
flow: range 1
to 69
oocysts/1 00
L; 8 of 1 1
samples
positive.
non-detect-
13,158
oocysts/
100L. 1
100L.
avg 22 1
oocysts/1 OOL
(max. 257
oocysts/
1 0OL) in 41
of 50 sam-
ples
Reference
Colbourne 1989
Roseetal. 1991.
1991c.
Cornwell and Lee
1993
1993.
2 642 oocysts/1 OOL 1
Cornwell and Lee
1993.
1993.
0.8 to 252/1 OOL; 33
of 39 samples posi-
tive 1 Karanis et al.
1996.
States et al 1 997
1997.
1 Karanis et al 1 998
The occurrence data available and
reported are primarily for raw and
recycle stream water. If filter backwash
enters the treatment train as a slug load
and disrupts the treatment process, it is
possible its effects would not be readily
seen in the finished water until several
minutes or hours after returning the
filter to service. In addition, the poor
recovery efficiencies of the IFA
Cryptosporidium detection method
complicate measurements in dilute
finished effluent waters.
As shown in Table II. 7, the
concentrations of oocysts in backwash
water and other recycle streams are
greater than the concentrations
generally found in raw water. For
example, four studies (Cornwell and
Lee, 1993; States et al., 1997; Rose et al.,
1986; and Colbourne, 1989] have
reported Cryptosporidium oocyst
concentrations in filter backwash water
exceeding 10,000 oocysts/lOOL. Such
concentrations illustrate that the
treatment plant has been removing
oocysts from the influent water during
the sedimentation and/or filtration
processes. As expected, the oocysts have
concentrated on the filters and/or in the
sedimentation basin sludge. Therefore,
the recycling of such process streams
(e.g., filter backwash, thickener
supernatant, sedimentation basin
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19059
sludge) re-introduces high
concentrations of oocysts to the
drinking water treatment train.
Recycle can potentially return a
significant number of oocysts to the
treatment plant in a short amount of
time, particularly if the recycle is
returned to the treatment process
without prior treatment, equalization, or
some other type of hydraulic detention.
In addition, Di Giovanni, et al. (1999)
presented data indicating that viable
oocysts have been detected in filter
backwash samples using a cell culture/
polymerase chain reaction (PCR)
method. Cell culture is a test of the
viability/infectivity of the oocysts, while
PCR identified the cells infected by C.
parvum. Although recovery by IFA was
poor (6 to 8 percent for backwash
samples), 9 filter backwash recycle
samples were found to contain viable
and infectious oocysts, and the
infectious agent was determined to be
more than 98 percent similar in
structure to C. parvum. Should filter
backwash recycle disrupt normal
treatment operations or should
treatment not function efficiently due to
other deficiencies, high concentrations
of potentially viable, infectious oocysts
may pass through the plant into finished
drinking water. The recycle stream
occurrence studies presented in Table
U.7 are described in further detail in the
following sections.
Thames, U.K. Water Utilities Experience
with Cryptosporidium, Colbourne (1989)
In response to a cryptosporidiosis
outbreak reported in February of 1989,
Thames Water undertook an
investigation of pathogen concentrations
within the Farmoor conventional
treatment plant's treatment train,
finished and raw \vaters. The
investigation occurred over a two month
period, from February to April 1989 and
included sampling of settled filter
backwash, the supernatant from spent
filter backwash, raw water, and water
sampled at the end of various Thames
distribution points.
On February 19,1989 at the start of
the outbreak investigation, a
concentration of approximately
1,000,000 oocysts/lOOL was detected in
the filter backwash water. During the
first few days of the following
investigation, the supernatant of the
settled backwash water contained
approximately 100,000 oocysts/lOOL. At
the peak of the outbreak, thirty percent
of Thames' distribution system samples
were positive for oocysts, and ranged in
concentration from 0.2 to 7700 oocysts/
100L. Raw reservoir water contained
oocyst concentrations ranging from .2 to
1400 oocysts/lOOL. After washing the
filters twice in 24 hours, no oocysts
were found in the settled backwash
waters. Thames, U.K. Water Utilities
determined that a storm causing intense
precipitation and runoff resulted in
elevated levels of oocysts in the source
water which led to the high
concentrations of oocysts entering the
plant and subsequently deposited on the
filters and recycled as filter backwash.
Survey of Potable Water Supplies for
Cryptosporidium and Giardia, Rose, et
al., 1991
In this survey, Rose, et al., collected
257 samples from 17 States from 1985
to 1988. The samples were collected on
cartridge filters and analyzed using
variations of the IFA method. The
reported percent recovery for the
method was 29 to 58 percent. Filter
backwash samples were a subset of the
257,10 to 40 L samples were collected
from rapid sand filters.
Rose, et al. reported the geometric
mean of the backwash samples at 217 -
Cryptosporidium oocysts/lOOL. This
was the highest reported average
Cryptosporidium concentration of any
of the water types tested, which
included polluted and pristine surface
and ground water sources, drinking
water sources in addition to filter
backwash recycle water.
Giardia and Cryptosporidium in Water
Supplies, LeChevallier, et al. (1991c)
LeChevallier et al. conducted a study
to determine "whether compliance with
the SWTR would ensure control of
Giardia in potable water supplies." Raw
water and plant effluent samples were
collected from 66 surface water
treatment plants in 14 States and one
Canadian province, although only
selected sites were tested for
Cryptosporidium oocysts in filter
backwash and settled backwash water.
In the analysis of pathogen
concentrations in the raw water and
filter backwash water of the water
treatment process, LeChevallier et al.
(1991c) found very high oocyst levels in
backwash water of utilities that had low
raw water parasite concentrations. The
pathogens were detected using a
combined IFA method that the authors
developed. Cryptosporidium levels in
the initial backwash water were 57 to 61
times higher than in the raw water
supplies. Raw water samples were
found to contain from 7 to 108 oocysts/
100L. LeChevallier et al. (1991c) also
noted that when Cryptosporidium were
detected in plant effluent samples (12 of
13 times), the organisms were also
observed in the backwash samples. The
study concluded that the consistency of
these results shows that accumulation of
parasites in the treatment filters (and
subsequent release in the filter
backwash recycle water) could be
related to subsequent passage through
treatment barriers.
Recycle Stream Effects on Water
Treatment, Comwell and Lee (1993,
1994)
The results described in Cornwell and
Lee's 1993 American Water Works
Association Research Foundation
Report and 1994 Journal of the
American Water Works Association
article on the Bangor and Moshannon
Valley, PA water treatment plants are
consistent with the results of States et
al. (1997). In total, Cornwell and Lee
investigated eight water treatment
plants, examining treatment efficiencies
including several recycle streams and
their impacts, and reporting a range of
pathogen and other water quality data.
All of the pathogen testing was
conducted using the EPA IFA method
refined by LeChevallier, et al. (1991c).
Cornwell and Lee (1993) conducted
two rounds of sampling at both the
Bangor and Moshannon plants,
sampling the different recycle and
treatment streams as eight-hour
composites. They detected
Cryptosporidium concentrations of over
16,500 Cryptosporidium oocysts/lOOL,
in the backwash water at an adsorption
clarifier plant (Moshannon Valley) and
over 850 Cryptosporidium oocysts/lOOL
in backwash water from a direct
filtration plant (Bangor). The parasite
levels in the backwash samples were
significantly higher than concentrations
found in the raw source water, which
contained Cryptosporidium oocyst
concentrations of 13-20 oocysts/lOOL at
the Moshannon Valley plant and 6-140
oocysts/lOOL at the Bangor plant.
In addition, Cornwell and Lee
determined oocyst concentrations for
two other recycle streams, combined ,
thickener supernatant and
sedimentation basin solids. The
supernatant pathogen concentrations
were reported at 141 Cryptosporidium
oocysts/lOOL at the Bangor plant, and
levels were reported at 82 to 420
oocysts/lOOL for the Moshannon plant
in Rounds 1 and 2 of sampling,
respectively. The sedimentation basin .
sludge was reported at 2,642 !
Cryptosporidium oocysts/lOOL in the
clarifier sludge from the Moshannon
Valley plant.
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Federal Register/Vol. 65, No. 69/Monday, April 10, 2000/Proposed Rules
Giardia and Cryptosporidium in
Backwash Water from Rapid Sand
Filters Used for Drinking Water, Karanis
et al. (1996) and Distribution and
Removal of Giardia and
Cryptosporidium in Water Supplies in
Germany Karanis, etal. (1998)
Karanis et al. (1996 and 1998)
conducted a four-year research study
(samples collected from July, 1993-
December, 1995) on the efficiency of
Cryptosporidium removal by six
different surface water treatment plants
from Germany, all of which treat by
conventional filtration. The method
used was an IF A method dubbed the
"EPA method", developed by
Jakubowski and Ericksen, 1979.
Karanis et al. (1996) detected
Cryptosporidium in 82 percent of the
samples of backwash water from rapid
sand filters of a water treatment plant
("Plant C") supplied by small rivers.
Eight out of 12 raw water samples tested
were positive for Cryptosporidium
(range of 0.8 to 109 oocysts/lOOL).
Backwash water samples collected by
continuous flow centrifugation were
positive for Cryptosporidium in 8 of 11
samples (range of 1 to 69/100L). Of 39
samples collected using cartridge filters,
33 were positive for Cryptosporidium
(range of 0.8 to 252/100L). The authors
called attention to the high detection
rate of Cryptosporidium in the
backwash waters (82 percent) of Plant C
and to the fact that the supernatant
following sedimentation was not free
from cysts and oocysts (Karanis et al.
1996).
In the 1998 publication, Karanis et al.
compiled the data from the 1996 study
with more backwash occurrence data
collected from another treatment plant
("Plant A"). The filter backwash of Plant
A was sampled 10 minutes after the
start of backwashing; and the backwash
water was found to contain 150
Cryptosporidium oocysts/lOOL.
Protozoa in River Water: Sources,
Occurrence, and Treatment, States, et
al. (1997)
Over a two year period (July, 1994-
June, 1996), States et al. sampled
monthly for Cryptosporidium in the
raw, settled, filtered and filter backwash
water at the Pittsburgh Drinking Water
Treatment Plant, in order to gauge the
efficiency of pathogen removal at the
plant. States et al. identified several
sources contributing oocysts to the
influent water, including sewage plant
effluent, combined sewer overflows,
dairy farm streams, and recycling of
backwash water. All pathogen sampling
was conducted with the IFA method.
Cryptosporidium occurred in the raw
Allegheny river water supplying the
plant with a geometric mean of 31
oocysts/lOOL in 63 percent of samples
collected, and ranged from non-detect to
2,333 oocysts/lOOL (see Table II.3 for
source water information). Of the filter
backwash samples, a geometric mean of
328 oocysts/lOOL was found at an
occurrence rate of 38 percent of
samples, with a range from non-detect
to 13,158 oocysts/lOOL. The fact that the
mean concentration of Cryptosporidium
oocysts in backwash water can be
substantially higher than the oocyst
concentration in untreated river water
suggests that recycling untreated filter
backwash water can be a significant
source of this parasite to water within
the treatment process.
F. Summary and Conclusions
Cryptosporidiosis is a disease without
a therapeutic cure, and its causative
agent, Cryptosporidium, is resistant to
chlorine disinfection. Cryptosporidium
has been known to cause severe illness,
especially in immunocompromised
individuals, and can be fatal. Several
waterborne Cryptosporidiosis outbreaks
have been reported, and it is likely that
others have occurred but have gone
unreported. Cryptosporidium has been
detected in a wide range of source
waters, documented in over 30 studies
from the literature, and it has been
found at levels of concern in filter
backwash water and other recycle
streams.
One of the key regulations EPA has
developed and implemented to counter
pathogens in drinking water is the
SWTR (54 FR 27486, June 19, 1989).
The SWTR requires that surface water
systems have sufficient treatment to
reduce the source water concentration
of Giardia and viruses by at least 99.9
percent (3 log) and 99.99 percent (4 log),
respectively. A shortcoming of the
SWTR, however, is that the rule does
not specifically control for
Cryptosporidium. The first report of a
recognized waterborne outbreak caused
by Cryptosporidium was published
during the development of the SWTR
(D'Antonio et al. 1985).
In 1998, the Agency finalized the
IESWTR that enhances the microbial
pathogen protection provided by the
SWTR for systems serving 10,000 or
more persons. The IESWTR includes an
MCLG of zero for Cryptosporidium and
requires a minimum 2-log (99 percent)
removal of Cryptosporidium, linked to
enhanced combined filter effluent and
individual filter turbidity control
provisions.
Several provisions of today's
proposed rule, the LTlFBR, are
designed to address the concerns
covered by the IESWTR, improving
control of Cryptosporidium and other
microbial contaminants, for the portion
of the public served by small PWSs (i.e.,
serving less than 10,000 persons). The
LTlFBR also addresses the concern that
for all PWSs that practice recycling,
Cryptosporidium (and other emerging
pathogens resistant to standard
disinfection practice) are reintroduced
to the treatment process of PWSs by the
recycle of spent filter backwash water,
solids treatment residuals, and other
process streams.
Insufficient treatment practices have
been cited as the cause of several
reported waterborne disease outbreaks
(Rose, 1997). Rose (1997) also found that
a reduction in turbidity is indicative of
a more efficient filtration process.
Therefore, the turbidity and filter
monitoring requirements of today's
proposed LTlFBR will ensure that the
removal process necessary to protect the
public from Cryptosporidiosis is
operating properly, and the recycle
stream provisions will ensure that the
treatment process is not disrupted or
operating inefficiently. The LTlFBR
requirements that address the potential
for Cryptosporidium to enter the
finished drinking water supply will be
described in more detail in the
following sections.
III. Baseline Information-Systems
Potentially Affected By Today's
Proposed Rule
EPA utilized the 1997 state-verified
version of the Safe Drinking Water
Information System (SDWIS) to develop
the total universe of systems which
utilize surface water or groundwater
under the direct influence (GWUDI) as
sources. This universe consists of
11,593 systems serving fewer than
10,000 persons, and 2,096 systems
serving 10,000 or more persons. Given
this initial baseline, the Agency
developed estimates of the number of
systems which would be affected by
components of today's proposed rule by
utilizing three primary sources: Safe
Drinking Water Information Systems;
Community Water Supply Survey; and
Water: Stats. A brief overview of each of
the data sources is described in the
following paragraphs.
Safe Drinking Water Information System
(SDWIS)
SDWIS contains information about
PWSs including violations of EPA's
regulations for safe drinking water.
Pertinent information in this database
includes system name and ID,
population served, geographic location,
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19061
type of source water, and type of
treatment (if provided).
Community Water System Survey
(CWSS)
EPA conducted the 1995 CWSS to
obtain data to support its development
and evaluation of drinking water
regulations. The survey consisted of a
stratified random sample of 3,700 water
systems nationwide (surface water and
groundwater). The survey asked 24
operational and 13 financial questions.
Waten/Stats (WaterStats)
WaterStats is an in-depth database of
water utility information compiled by
the American Water Works Association.
The database consists of 898 utilities of
all sizes and provides a variety of data
including treatment information.
Information regarding estimates of the
number of systems which may
potentially be affected by specific
components of today's proposed rule
can be found in the discussion of each
proposed rule component in Section IV.
IV. Discussion of Proposed LTlFBR
Requirements
A. Enhanced Filtration Requirements
As discussed earlier in this preamble,
one of the key objectives of today's
proposed rule is ensuring that an
adequate level of public health
protection is maintained in order to
minimize the risk associated with
Cryptosporidium. While the current
SWTR provides protection from viruses
and Giardia, it does not specifically
address Cryptosporidium, which has
been linked to outbreaks resulting in
over 420,000 cases of gastrointestinal
illness in the 1990s (403,000 associated
with the Milwaukee outbreak). Because
of Cryptosporidium's resistance to
disinfection practices currently in place
at small systems throughout the ,
country, die Agency believes enhanced
filtration requirements are necessary to
improve control of this microbial
pathogen.
In the IESWTR, the Agency utilized
an approach consisting of three major
components to address Cryptosporidium
at plants serving populations of 10,000
or more. The first component required
systems to achieve a 2 log removal of
Cryptosporidium. The second :
component consisted of strengthened
turbidity requirements for combined
filter effluent. The third component
required individual filter turbidity
monitoring.
In today's proposed rule addressing
systems serving fewer than 10,000
persons, the Agency is utilizing the
same framework. Where appropriate,
EPA has evaluated additional options in
an effort to alleviate burden on small
systems while still maintaining a
comparable level of public health
protection.
The following sections describe the
overview and purpose of each of the
rule components, relevant data utilized
during development, the requirements
of today's proposed rule (including
consideration of additional options
where appropriate), and a request for
comment regarding each component.
1. Two Log Cryptosporidium Removal
Requirement
a. Two Log Removal
i. Overview and Purpose
The 1998 IESWTR (63 FR 69477,
December 16,1998) establishes an
MCLG of zero for Cryptosporidium in
order to adequately protect public
health. In conjunction with the MCLG,
the IESWTR also established a treatment
technique requiring 2 log
Cryptosporidium removal for all surface
water and GWUDI systems which filter ,
and serve populations of 10,000 or more
people, because it was not economically
and technologically feasible to
accurately ascertain the level of
Cryptosporidium using current
analytical methods. The Agency
believes it is appropriate and necessary
to extend this treatment technique of 2
log Cryptosporidium removal
requirement to systems serving fewer
than 10,000 people.
ii. Data
As detailed later in this section, EPA
believes that the data and principles
supporting requirements established for
systems serving populations of 10,000
or more are also applicable to systems
serving populations fewer than 10,000.
The following section provides
information and data regarding: (1) the
estimated number of small systems
subject to the proposed 2 log
Cryptosporidium removal requirement;
and (2) Cryptosporidium removal using
various filtration technologies.
Estimate of the Number of Systems
Subject to 2 log Cryptosporidium
Removal Requirement
Using the baseline described in
Section III of today's proposed rule, the
Agency applied percentages of surface
water and GWUDI systems which filter
(taken from the 1995 CWSS) in order to
develop an estimate of the number of
systems which filter and serve fewer
than 10,000 persons. This resulted in an
estimated 9,133 surface water and
GWUDI systems that filter which may
be subject to the proposed removal
requirement. Table IV. 1 provides this
estimate broken down by system size
and type.
TABLE IV.1 .—ESTIMATE OF SYSTEMS SUBJECT TO 2 LOG CRYPTOSPORIDIUM REMOVAL REQUIREMENT3
System type
Community
Non Community
NTNC
Total
Population served
<100
888
1099
214
2201
101-500
1453
374
204
2031
501-1K"
950
' 78
I 82
' 1110
1K-3.3K>>
2022
64
64
2150
3.3K-10Ki>
1591
35
17
1643
Total #Sys.
6903
16491
581
»9134b
•Numbers may not add due to rounding
bK = thousands •
Cryptosporidium Removal Using Conventional and Direct Filtration
During development of the LTlFBR, the Agency reviewed the results of several studies that demonstrated the ability
of conventional and direct filtration systems to achieve 2 log removal of Cryptosporidium at well operated plants achieving
low turbidity levels. Table IV.2 provides key information from these studies. A brief description of each study follows
the table.
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TABLE IV.2.—CONVENTIONAL AND DIRECT FILTRATION REMOVAL STUDIES
Type of treatment
Log removal
Experimental design
Researcher
Conventional
Direct filtration
Rapid Granular Fil-
tration (alone).
Cryptosporidium 4.2-5.2 .
Giardia 4.1-5.1
Cryptosporidium 1.9-4.0 .
Giardia 2.2-3.9
Cryptosporidium 1.9-2.8 .
Giardia 2.8-3.7
Cryptosporidium 2.3-2.5 .
Giardia 2.2-2.8
Cryptosporidium 2-3
Giardia and Crypto 1.5-2
Cryptosporidium 4.1-5.2 .
Cryptosporidum .2-1.7 .....
Cryptosporidium 2.7-3.1
Giardia 3.1-3.5
Cryptosporidium 2.7-5.9
Giardia 3.4-5.0
Cryptosporidium 1.3-3.8
Giardia 2.9-4.0
Cryptosporidium 2-3
Cryptosporidium 2.3-4.9
Giardia 2.7-5.4
Pilot plants
Pilot plants
Pilot-scale plants
Pilot-scale plants
Full-scale plants
Full-scale plants
Full-scale plants
Full-scale plants
Pilot plants
Full-scale plant (operation considered
not optimized).
Pilot Plant (optimal treatment)
Pilot Plant (suboptimal treatment)
Pilot plants
Pilot plants
Pilot plants
Pilot plants
Pilot plants
Pilot plants
Pilot plants
Pilot plant .
Patania et al. 1995
Patania et al. 1995
Nieminski/Ongerth 1995
Nieminski/Ongerth 1995
Nieminski/Ongerth 1995
Nieminski/Ongerth 1995
LeChevallier and Norton 1992
LeChevallier and Norton 1992
Foundation for Water Research, Britain
1994
Kelley etal. 1995
Dugan et al. 1999
Dugan et al. 1999
Ongerth/Pecaroro 1995
Ongerth/Pecaroro 1995
Patania et al. 1995
Patania ef al. 1995
Nieminski/Ongerth 1995
Nieminski/Ongerth 1995
West etal. 1994
Swertfeger et al., 1998
Patania, NancyL, etal. 1995
This study consisted of four pilot
studies which evaluated treatment
variables for their impact on
Cryptosporidium and Giardia removal
efficiencies. Raw water turbidities in the
study ranged between 0.2 and 13 NTU.
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 Giardia 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, 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).
Cryptosporidium removal rates of less
than 2.0 log occurred at the end of the
filtration cycle. '•
Nieminski, Eva C. and Ongerth, ferry E.
1995
This 2-year study evaluated Giardia
and Cryptosporidium cyst removal
through direct and conventional
filtration. The source water of the full
scale plant had turbidities typically
between 2.5 and 11 NTU with a
maximum 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,
Cryptosporidium 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
differences in source water quality
during the filter runs.
Ongerth, ferry E. and Pecaroro, f.P. 1995
A 1 gallon per minute (gpm) pilot
scale water filtration plant was used to
measure removal efficiencies of
Cryptosporidium and Giardia using very
low turbidity source waters (0.35 to 0.58
NTU). With optimal coagulation, 3 log
removal for both pathogens were
obtained. In one test run, where
coagulation was intentionally sub-
optimal, the removals were only 1.5 log
for Cryptosporidium and 1.3 log for
Giardia. This demonstrates 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
The purpose of this study was to
evaluate the relationships among
Giardia, Cryptosporidium, turbidity,
and particle counts in raw water and
filtered water effluent samples at three
different systems. Source water
turbidities ranged from less than 1 to
120 NTU. Removals of Giardia and
Cryptosporidium (2.2 to 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
operated within varying stages of
treatment optimization. The median
removal achieved was 2.5 log for
Cryptosporidium and Giardia.
LeChevallier, Mark W.; Norton, William
D.; and Lee, Raymond G. 199lb
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 oocysts
were detected in the finished water,
occurrence levels were assumed at the
detection limit for calculating removal
efficiencies.
Foundation for Water Research 1994
This study evaluated
Cryptosporidium removal efficiencies
for several treatment processes
(including conventional filtration) using
a pilot plant and bench-scale testing.
Raw water turbidity ranged from 1 to 30
NTU. Cryptosporidium oocyst removal
was between 2 and 3 log using
conventional filtration. Investigators
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19063
concluded that any measure which
reduced filter effluent turbidity should
reduce risk from Cryptosporidium, and
also showed the importance of selecting
proper coagulants, dosages, and
treatment pH. In addition to turbidity,
increased color and dissolved metal ion
coagulant concentration in the effluent
are indicators of reduced efficiency of
coagulation/flocculation and possible
reduced oocysts removal efficiency.
Kelley, M.B. et al. 1995
This study evaluated two U.S. Army
installation drinking water treatment
systems for the removal of Giardia and
Cryptosporidium. Protozoa removal was
between 1.5 and 2 log. The authors
speculated that this low
Cryptosporidium removal efficiency
occurred because the coagulation
process was not optimized, although the
finished water turbidity was less than
0.5 NTU.
West, Thomas; et al. 1994
This study evaluated the removal
efficiency of Cryptosporidium through
direct filtration using anthracite mono-
media at filtration rates of 6 and 14
gpm/sq.ft. Raw water turbidity ranged
from 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. Log removal declined
significantly during particle
breakthrough. When effluent turbidity
was less than 0.1 NTU, removal
typically exceeded 2 log. Log removals
of Cryptosporidium generally exceeded
that for particle removal.
Swertfeger et al., 1998
The Cincinnati Water Works
conducted a 13 month pilot study to
determine the optimum filtration media
and depth of the media to replace media
at its surface water treatment plant. The
study investigated cyst and oocyst
removal through filtration alone
(excluding chemical addition, mixing,
or sedimentation) and examined sand
media, dual media, and deep dual
media. Cyst and oocyst removal by each
of the media designs was > 2.5 log by ;
filtration alone.
Duganetal, 1999
EPA conducted pilot scale
experiments to assess the ability of
conventional treatment to control
Cryptosporidium oocysts under steady
state conditions. The work was
performed with a pilot plant designed to
minimize flow rates and the number of
oocysts required for spiking. With
proper coagulation control, the
conventional treatment process
achieved at least 2 log removal of
Cryptosporidium. In all cases where 2
log removal was not achieved, the plant
also did not comply with the IESWTR
filter effluent turbidity requirements.
All of 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). Other
key points 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 Table IV.2.a tend to be,
for low-turbidity waters, which are
considered to be the most difficult to
treat regarding particulate removal and
associated protozoan removal.
• Because high removal rates were
demonstrated in pilot studies using
lower-turbidity source waters, it is
likely that similar or higher removal
rates can be achieved for higher-
turbidity source waters.
• Determining Cryptosporidium
removal in full-scale plants can be
difficult due to the fact that data
includes many non-detects in the
finished water. In these cases, finished
water concentration levels are assigned
at the detection limit and are likely to
result in over-estimation of oocysts in
the finished water. This tends to under-
estimate removal levels.
• 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 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), the following
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; and
—A significant percentage of these
systems were also achieving low
filtered water turbidities,
substantially less than 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).
Cryptosporidium Removal Using Slow
Sand and Diatomaceous Earth Filtration
During development of the IESWTR,
the Agency also evaluated several
studies which demonstrated that slow
sand and diatomaceous earth filtration
were capable of achieving at least 2 log
removal of Cryptosporidium. Table IV. 3
provides key information from these
studies. A brief description of each
study follows the table.
TABLE IV.3— SLOW SAND AND DIATOMACEOUS EARTH FILTRATION REMOVAL STUDIES
Type of treatment
Log removal
Giardia & Cryptosporidium > 3
Cryptosporidium 3 3—6 68
Experimental design
Pilot plant at 4 5 to 16 5°C
Full-scale plant
Pilot plant
Bench scale
Researcher
Shuler and Ghosh 1991.
imms et. al. 1995.
Shuler et. al. 1990.
Ongerth & Hutton, 1997.
Shuler and Ghosh 1991
This pilot study was conducted to
evaluate the ability of slow sand filters
to remove Giardia, Cryptosporidium,
coliforms, and turbidity. The pilot study
was conducted at Pennsylvania State
University using a raw water source
with a turbidity ranging from 0.2-0.4
NTU. Influent concentration of
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Cryptosporidium oocysts during the
pilot study ranged from 1,300 to 13,000
oocysts/gallon. Oocyst removal was
shown to be greater than 4 log.
Timms et al 1995
This pilot study was conducted to
evaluate the efficiency of slow sand
filters at removing Cryptosporidium. A
pilot plant was constructed of 1.13 m2
in area and 0.5 m in depth with a
filtration rate of 0.3m/h. The filter was
run for 4—5 weeks before the experiment
to ensure proper operation.
Cryptosporidium oocysts were spiked to
a concentration of 4,000/L. Results of
the study indicated a 4.5 log removal of
Cryptosporidium oocysts.
Shuler et al 1990
In this study, diatomaceous earth (DE)
filtration was evaluated for removal of
Giardia, Cryptosporidium, turbidity and
coliform bacteria. The study used a
O.lm2 pilot scale DE filter with three
grades of diatomaceous earth (A, B, and
C). The raw water turbidity varied
between 0.1 and 1 NTU. Filter runs
ranged from 2 days to 34 days. A greater
than 3 log removal of Cryptosporidium
was demonstrated in the 9 filter runs
which made up the study.
Ongerth and Hutton, 1997
Bench scale studies were used to
define basic characteristics of DE
filtration as a function of DE grade and
filtration rate. Three grades of DE were
used in the tests. Cryptosporidium
removal was measured by applying river
water seeded with Cryptosporidium to
Walton test filters. Tests were run for
filtration rates of 1 and 2 gpm/sq ft.
Each run was replicated 3 times.
Approximately 6 logs reduction in the
concentration of Cryptosporidium
oocysts was expected under normal
operating conditions.
Cryptosporidium Removal Using
Alternative Filtration Technologies
EPA recognizes that systems serving
fewer than 10,000 individuals employ a
variety of filtration technologies other
than those previously discussed. EPA
collected information regarding several
other popular treatment techniques in
an effort to verify that these treatments
were also technically capable of
achieving a 2 log removal of
Cryptosporidium. A brief discussion of
these alternative technologies follows
along with studies demonstrating
effective Cryptosporidium removals.
Membrane Filtration
Membrane filtration (Reverse
Osmosis, Nanofiltration, Ultrafiltration,
and Microfiltration) relies upon pore
size in order to remove particles from
water. Membranes possess a pore size
smaller than that of a Cryptosporidium
oocyst, enabling them to achieve
effective log removals. The smaller the
pore size, the more effective the rate of
removal. Typical pore sizes for each of
the four types of membrane filtration are
shown below:
• Microfiltration—1-0.1 microns
(am)
• Ultrafiltration—0.1-.01 (urn)
• Nanofiltration—.01-.001 (urn)
• Reverse Osmosis—<.001 (urn)
Bag Filtration
Bag filters are non-rigid, disposable,
fabric filters where water flows from
inside of the bag to the outside of the
bag. One or more filter bags are
contained within a pressure vessel
designed to facilitate rapid change of the
filter bags when the filtration capacity
has been used up. Bag filters do not
generally employ any chemical
coagulation. The pore sizes in the filter
bags designed for protozoa removal
generally are small enough to remove
protozoan cysts and oocysts but large
enough that bacteria, viruses and fine
colloidal clays would pass through. Bag
filter studies have shown a significant
range of results in the removal of
Cryptosporidium oocysts (0.33-3.2 log).
(Goodrich, 1995)
Cartridge Filtration
Cartridge filtration also relies on
physical screening to remove particles
from water. Typical cartridge filters are
pressure filters with glass, fiber or
ceramic membranes, or strings wrapped
around a filter element housed in a '
pressure vessel (USEPA, 1997a).
The Agency evaluated several studies
which demonstrate the ability of various
alternative filtration technologies to
achieve 2 log removal of
Cryptosporidium (in several studies 2
log removal of 4-5 (um) microspheres
were used as a surrogate for
Cryptosporidium). These studies
demonstrate that 2 log removal was
consistently achievable in all but bag
filters. Table IV.4 provides key
information from these studies. A brief
description of each study follows:
TABLE IV.4.—ALTERNATIVE FILTRATION REMOVAL STUDIES
Type of treatment
Microfiltration
Ultrafiltration '....
Reverse Osmosis ....
Hybrid Membrane ...
Bag Filtration
Cartridge filtration ....
Log removal
Cryptosporidium 4.2—4.9 log . .. .
Giardia 4.6—5.2 log
Cryptosporidium 6.0 — -7.0 log
Cryptosporidium 4.3 — 5.0 log
Cryptosporidium 7.0—7 7 log
Microspheres 3 57—3 71 log
Cryptosporidium 4.4 — 4.9 log
Giardia 4 7-5 2 log
Cryptosporidium 5.73—5.89 log
Giardia 5.75— 5.85 log
Cryptosporidium 7.1—7.4 log
Cryptosporidium 3.5 log
Microspheres 3—4 log
Cryptosporidium > 5 7 log
Giardia > 5.7 log.
Microspheres 4.18 log
Microspheres .33—3 2 log .
Microspheres 3.52-3.68 log
Particles (5—1 5 um) > 2 log
Experimental design
Bench Scale
Pilot Plant
Pilot Plant
Bench Scale
Full Scale
Bench Scale
Bench Scale
Bench Scale
pilot Plant
Pilot Scale
Bench Scale
Pilot Plant
Pilot Plant
Bench Scale
Researcher
Jacangelo et al 1997
Drozd & Schartzbrod 1 997
Hirata & Hashimoto 1998
Goodrich et al 1995 ' >
Jacangelo et al 1997 •
Collins ef al 1996
Hirata & Hashimoto 1998
Lykins et al 1 994 •
Adham et al 1998
Goodrich et al 1995
Goodrich et al 1995
Goodrich et al 1995
Land 1998
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19065
Jacangelo et al., 1997
Bench scale and pilot plant tests were
conducted with microfiltration and
ultrafiltration filters (using six different
membranes) in order to evaluate
microorganism removal. Bench scale
studies were conducted under worst
case operating conditions (direct flow
filtration at the maximum recommended
transmembrane pressure using
deionized water slightly buffered at pH
7). Log removal ranged from 4.7 to 5.2
log removal. Pilot plant results ranged
from 6.0—7.0 log removal during worst-
case operating conditions (i.e., direct
filtration immediately after backwashing
at the maximum recommended
operating transmembrane pressure).
DrozdandSchartzbrod, 1997
A pilot plant system was established
to evaluate the removal of
Cryptosporidium using crossflow
microfiltration (.2 um porosity). Results
demonstrated Cryptosporidium log
removals of 4.3 to greater than 5.5 with
a corresponding mean filtrate turbidity
of0.25NTU.
Collins et. al., 1996
This study consisted of bench scale
testing of Cryptosporidium and Giardia
log removals using an ultrafiltration
system. Log removal of Cryptosporidium
ranged from 5.73 to 5.89 log, while
removal of Giardia ranged from 5.75 to
5.85 log.
Hirata G-Hashimoto, 1998
Pilot scale testing using
microfiltration (nominal pore size of .25
um) and ultrafiltration (nominal cut-off
molecular weight (MW) 13,000 daltons)
was conducted to determine
Cryptosporidium oocyst removal.
Results conducted on the ultrafiltration
units ranged from 7.1 to 7.5 logs of
Cryptosporidium removal. Results of the
microfiltration studies yielded log
removals from 7.0 to 7.7 log.
Lykirts et al., [1994]
An ultrafiltration system was
evaluated for the removal of
Cryptosporidium oocysts at the USEPA
Test and Evaluation Facility in
Cincinnati, Ohio. The filter run was just
over 48 hours. A 3.5 log removal of
Cryptosporidium oocysts was observed.
Additionally, twenty-four experiments
were performed using 4.5 um
polystyrene microspheres as a surrogate
for Cryptosporidium because of a
similar particle distribution. Log
removal of microspheres ranged from 3
to 4 log.
Adham et al., 1998
This study was conducted to evaluate
monitoring methods for membrane
integrity. In addition to other activities,
microbial challenge tests were
conducted on reverse osmosis (RO)
membranes to both determine log
removals and evaluate system integrity.
Log removal of Cryptosporidium and '.
Giardia was >5.7 log in uncompromised
conditions, and > 4.5 log in
compromised conditions.
Goodrich et al., 1995
This study was conducted to evaluate
removal efficiencies of three different
bag filtration systems. Average filter
pore size of the filters was 1 um while
surface area ranged from 35 to 47 sq ft.
Bags were operated at 25, 50 and 100
percent of their maximum flow rate
while spiked with 4.5 um polystyrene
microspheres (beads) as a surrogate for
Cryptosporidium. Bead removal ranged
from .33 to 3.2 log removal.
Goodrich et al 1995.
This study evaluated a cartridge filter
with a 2 um rating and 200 square feet
of surface area for removal efficiency of
Cryptosporidium sized particles. The
filter was challenge tested with 4.5 um
polystyrene microspheres as a surrogate
for Cryptosporidium. Flow was set at 25
gpm with 50 psi at the inlet. Results
from two runs under the same
conditions exhibited log removals of
3.52 and 3.68.
Land, 1998
An alternative technology
demonstration test was conducted to
evaluate the ability of a cartridge filter
to achieve 2 log removal of particles in
the 5 to 15 um range. The cartridge
achieved at least 2 log removal of the 5
to 25 um particles 95 percent of the time
up to a 20 psi pressure differential. The
filter achieved at least 2 log removal of
5 to 15 um particles up to 30-psi
pressure differential.
While the studies above note that
alternative filtration technologies have
demonstrated in the lab the capability to
achieve a 2 log removal of
Cryptosporidium, the Agency believes
that the proprietary nature of these
technologies necessitates a more
rigorous technology-specific
determination be made. Given this
issue, the Agency believes that its
Environmental Technology Verification
(ETV) Program can be utilized to verify
the performance of innovative
technologies. Managed by EPA's Office
of Research and Development, ETV was
created to substantially accelerate the,
entrance of new environmental
technologies into the domestic and
international marketplace. ETV consists
of 12 pilot programs, one of which
focuses on drinking water. The program
contains a protocol for physical removal
of microbiological and particulate
contaminants, including test plans for
bag and cartridge filters and membrane
filters (NSF, 1999). These protocols can
be utilized to determine whether a
specific alternative technology can
effectively achieve a 2 log removal of
Cryptosporidium, and under what
parameters that technology must be
operated to ensure consistent levels of
removal. Additional information on the
ETV program can be found on the
Agency's website at http://
www.epa.gov/etv.
iii. Proposed Requirements
Today's proposed rule establishes a
requirement for 2 log removal of
Cryptosporidium for surface water and
GWUDI systems serving fewer than
10,000 people that are required to filter
under the SWTR. Compliance with the
combined filter effluent turbidity
requirements, as described later, ensures
compliance with the 2 log removal
requirement. The requirement for a 2 log
removal of Cryptosporidium applies
between a point where the raw water is
not subject to recontamination by
surface water runoff and a point
downstream before or at the first ;
customer.
iv. Request for Comments
EPA requests comment on the 2 log
removal requirement as discussed. The
Agency is also soliciting public
comment and data on the ability of
alternative filtration technologies to
achieve 2 log Cryptosporidium removal.
2. Turbidity Requirements
a. Combined Filter Effluent
i. Overview and Purpose
In order to address concern with
Cryptosporidium, EPA has analyzed log
removal performance by well operated
plants (as described in the previous
section) as well as filter performance
among small systems to develop an
appropriate treatment technique
requirement that assures an increased
level of Cryptosporidium removal. In ,
evaluating combined filter performance
requirements, EPA considered the
strengthened turbidity provisions
within the IESWTR and evaluated ',
whether these were appropriate for
small systems as well.
ii. Data
In an effort to evaluate combined filter
effluent (CFE) requirements, EPA
collected data in several areas to
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Federal Register/Vol. 65, No. 69/Mpnday, April 10, 2000/Proposed Rules
supplement existing data, and address
situations unique to smaller systems.
This data includes: .
. • An estimate of the number of ,
systems subject to the proposed
strengthened turbidity requirements;
• Current turbidity levels at systems
throughout the U.S. serving populations
fewer than 10,000; \
• The ability of package plants to
meet strengthened turbidity standards;
and
• The correlation between meeting
CFE requirements and achieving 2 log
removal of Cryptosporidium.
Estimate of the Number of Systems
Subject to Strengthened CFE Turbidity
Standards
Using the estimate of 9,134 systems
which filter and serve fewer than 10,000
persons (as described in Section IV.A.I
i of today's proposal), the Agency used
the information contained within 'the
CWSS database to estimate the number
of systems which utilized specific types
of filtration. The data was segregated
based on the type of filtration utilized
and the population size of the system.
Percentages were derived for each of the
following types of filtration:
• Conventional and Direct Filtration;
• Slow Sand Filtration;
• Diatomaceous Earth Filtration; and
• Alternative Filtration Technologies.
The percentages were applied to the
estimate discussed in Section IV.A.I of
today's proposal for each of the
respective population categories. Based
on this .analysis, the Agency estimates
5,896 conventional and direct filtration
systems will be subject to the
strengthened combined filter effluent
turbidity standards. EPA estimates 1,756
systems utilize slow sand or
diatomaceous earth filtration, and must
continue to meet turbidity standards set
forth in the SWTR. The remaining 1,482
systems are estimated to use alternative
filtration technologies and will be
required to meet turbidity standards as
set forth by the State upon analysis of
a 2 log Cryptosporidium demonstration
conducted by the system.
Current Turbidity Levels
EPA has developed a data 'set which
summarizes the historical turbidity
performance of various filtration plants
serving populations fewer than 10,000
(EPA, 1999d). The data set represents
those systems that were in compliance
with the turbidity requirements of the
SWTR during all months being
analyzed. The data set consists of 167
plants from 15 States. Table IV.5
provides information regarding the
number of plants from each State. The
data set includes plants representing
each of the five population groups
utilized in the CWSS (25-100,101-500,
501-1,000,1,001-3,300, and 3,301-
10,000). The Agency has also received
an additional data set from the State of
California (EPA, 2000). This data has
not been included'in the assessments
described below. The California data
demonstrates similar results to the
larger data set discussed below.
TABLE IV.5.—SUMMARY OF LT1FBR
TURBIDITY DATA SET
State
Alabama
California
Colorado
Illinois
Kansas
Minnesota
Montana .. . ....
North Carolina ,
Ohio
Pennsylvania
South Carolina
Texas
Washington :..........
West Virginia
Total
Number of
Plants
1
1
16
13
20
6
3
2
16
4
27
16
, 23
17
2
167
This data was evaluated to assess the
national impact of modifying existing
turbidity requirements. The current
performance of plants was assessed with
respect to the number of months'in
which selected 95th percentile and
maximum turbidity levels were met.
The data show that approximately 88
percent of systems are also Currently
meeting the new requirements of a
maximum turbidity limit of 1 NTU
(Figure IV.l). With respect to the 95th
percentile turbidity limit, roughly 46
percent of these systems are currently
meeting the new requirement of 0.3
NTU (Figure IV. 2) while approximately
70 percent meet this requirement 9
months out of the year. Estimates for
systems needing to make changes to
meet a turbidity performance limit of
0.3 NTU were based on the ability of
systems currently to meet a 0.2 NTU.
This assumption was intended to take
into account a utility's concern with
possible turbidity measurement error
and to reflect the expectation that a
number of utilities will attempt to
achieve finished water turbidity levels
below the regulatory performance level
to assure compliance.
As depicted in Figure IV.l and IV.2,
the tighter turbidity performance
standards for combined filter effluent in
today's proposed rule reflect the actual,
current performance many systems
already achieve nationally. Revising the
turbidity criteria effectively ensures that
these systems continue to perform at
their current level while also improving
performance of a substantial number of
systems that currently meet existing
SWTR criteria, but operate at turbidity
levels higher than proposed in today's
rule.
BILLING CODE 6560-50-P
(EPA, 1999d)
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19067
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Federal Register/Vol. 65, No. 69/Monday, April 10, 2000/Proposed Rules
19069
Package Plants
During development of today's
proposed rule, some stakeholders
expressed concern regarding the ability
of "package plants" to meet the
proposed requirements. EPA evaluated
these systems by gathering data from
around the country. The information
affirms the Agency's belief that package
plants can and currently do meet the
turbidity limits in today's proposed
rule.
Package plants combine the processes
of rapid mixing, flocculation,
sedimentation and filtration (rapid sand,
mixed or dual media filters) into a
single package system. Package
Filtration Plants are preconstructed,
skid mounted and transported virtually
assembled to the site. The use of tube
settlers, plate settlers, or adsorption
clarifiers in some Package Filtration
Plants results in a compact size and
more treatment capacity.
Package Filtration Plants are
appropriate for treating water of a fairly
consistent quality with low to moderate
turbidity. Effective treatment of source
waters containing high levels of or
extreme variability in turbidity levels
requires skilled operators and close
operational attention. High turbidity or
excessive color in the source water
could require chemical dosages above
the manufacturer's recommendations for
the particular plant. Excessive turbidity
levels may require presedimentation or
a larger capacity plant. Specific design
criteria of a typical package plant and
operating and maintenance
requirements can vary, but an example
schematic is depicted in Figure IV.3.
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Federal Register/Vol. 65, No. 69/Monday, April 10, 2000/Proposed Rules
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Federal Register/Vol. 65, No. 69/Monday, April 10, 2000/Proposed Rules
19071
The Agency believes that historic data
show that package plants have a
comparable ability to meet turbidity
requirements as conventional or direct
filtration systems.
A 1987 report of pilot testing using a
trailer-mounted package plant system to
treat raw water from Clear Lake in
Lakeport, California demonstrates the
ability of such systems to achieve low
turbidity requirements. The raw water
contained moderate to high turbidity (18
to 103 NTU). Finished water turbidities
ranged from 0.07 to 0.11 NTU (EPA,
1987). Two previous studies (USEPA,
1980a,b and Cambell et al., 1995) also
illustrate the ability of package systems
throughout the country to meet historic
turbidity performance criteria. These
studies are described briefly:
Package Water Treatment Plant
Performance Evaluation (USEPA,
1980a,b)
The Agency conducted a study of
package water treatment systems which
encompassed 36 plants in Kentucky,
West Virginia, and Tennessee. Results
from that study showed that the plants
could provide water that met the
existing turbidity limits established
under the National Interim Primary
Drinking Water Standards. Of the 31
plants at which turbidity measurements
were made, 23 (75 percent) were found
to be meeting existing standards. Of the
8 which did not meet requirements, one
did not use chemical coagulants, and 6
operated les's than four hours per day.
(USEPA, 1980a, b)
Package Plants for Small Systems: A
Field Study (Cambell et al, 1995)
This 1992 project evaluated the
application of package plant technology
to small communities across the U.S.
The project team visited 48 facilities
across the U.S. Of the 29 surface water
and GWUDI systems, 21 (72 percent)
had grab turbidity samples less than 0;5
NTU, the 95 percent limit which
became effective in June of 1993.
Twelve systems (41 percent) had values
less than today's proposed 0.3 NTU 95
percent turbidity limit. (Cambell et al.,
1995) It should be noted that today's
rule requires compliance with turbidity
limits based on 4 hour measurments.
The Agency recently evaluated Filter
Plant Performance Evaluations (FPPEs)
conducted by the State of Pennsylvania,
in an effort to quantify the comparative
abilities of package plants and
conventional filtration systems to meet
the required turbidity limits. The data
set consisted of 100 FPPEs conducted at
systems serving populations fewer than
10,000 (PADEP, 1999). Thirty-seven
FPPEs were conducted at traditional
conventional filtration systems while 37
were conducted at package plants or
"pre-engineered" systems. The
remaining 26 systems utilized other
filtration technologies.
The FPPEs provided a rating of either
acceptable or unacceptable as
determined by the evaluation team. This
rating was based on an assessment of
the capability of individual unit
processes to continuously provide an
effective barrier to the passage of
microorganisms. Specific performance
goals were utilized to evaluate the
performance of the system including the
consistent ability to produce a finished
water turbidity of less than 0.1 NTU,
which is lower than the combined filter
effluent turbidity requirement in today's
proposed rule. Seventy-three percent of
the traditional conventional filtration
systems were rated acceptable and 89
percent of the package plants were rated
acceptable.
The Agency also evaluated historic
turbidity data graphs contained within
each FPPE to provide a comparison of
the ability of package plants and
conventional systems to meet the 1 NTU
max and 0.3 NTU 95 percent
requirements that are contained in
today's proposed rule. Sixty-seven
percent of the conventional systems
would meet today's proposed
requirements while 74 percent of
package systems in the data set would
meet today's proposed requirements.
The Agency believes that, when viewed
alongside the aforementioned studies
(USEPA, 1980a,b and Cambell et al.,
1995), it is apparent that package
systems have the ability to achieve more
stringent turbidity limits.
Correlation Between CFE Requirements
and 2-log Cryptosporidium Removal
Recent pilot scale experiments
performed by the Agency assessed the
ability of conventional treatment to
control Cryptosporidium under steady
state conditions. The work was
performed with a pilot plant that was
designed to minimize flow rates and as
a result the number of oocyst required
for continuous spiking. (Dugan et al.
1999)
Viable oocysts were fed into the plant
influent at a concentration of 106/L for
36 to 60 hours. The removals of oocysts
and the surrogate parameters turbidity,
total particle counts and aerobic
endospores were measured through
sedimentation and filtration. There was
a positive correlation between the log
removals of oocysts and all surrogate
parameters through the coagulation and
settling process. With proper
coagulation control, the conventional
treatment process achieved the 2 log
total Cryptosporidium removal required
by the IESWTR. In all cases where 2 log
total removal was not achieved, the
plant also did not comply with the
lESWTR's CFE turbidity requirements.
Table IV.6 provides information on
Cryptosporidium removals from this
study. ;
TABLE IV.6.—LOG REMOVAL OF OOCYSTS (DUGAN ET AL. 1999)
Run
1
2
3 ,
4
5
6
7
8 ,
9
10
Log removal
crypto
4.5
5.2
1.6
1.7
4.1
5.1
0.2
0.5
5.1
4.8
Exceeds CFE
No.
No.
Yes, average CFE 2.1 NTU.
Yes, only 88% CFE under 0.3 NTU.
No.
No.
Yes, average CFE 0.5 NTU.
Yes, only 83% CFE under 0.3 NTU.
No.
No. :
requirements
*
i
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Federal Register/Vol. 65, No. 69/Monday, April 10, 2000/Proposed Rules
iii. Proposed Requirements
Today's proposed rule establishes
combined filter effluent turbidity
requirements which apply to all surface
water and GWUDI systems which filter
and serve populations fewer than
10,000. For conventional and direct
filtration systems, the turbidity level of
representative samples of a system's
combined filter effluent water must be
less than or equal to 0.3 NTU in at least
95 percent of the measurements taken
each month. The turbidity level of
representative samples of a system's
filtered water must not exceed 1 NTU at
anytime.
For membrane filtration,
(microfiltration, ultrafiltration,
nanofiltration, and reverse osmosis) the
Agency is proposing to require that the
turbidity level of representative samples
of a system's combined filter effluent
water must be less than or equal to 0.3
NTU in at least 95 percent of the
measurements taken each month. The
turbidity level of representative samples
of a system's filtered water must not
exceed 1 NTU at any time. EPA
included turbidity limits for membrane
systems to allow such systems the
ability to opt out of a possible costly
demonstration of the ability to remove
Cryptosporidium. The studies displayed
previously in Table IV.4, demonstrate
the ability of these technologies to
achieve log-removals in excess of 2 log.
In lieu of these turbidity limits, a public
water,system which utilizes membrane
filtration may demonstrate to the State
for purposes of membrane approval
(using pilot plant studies or other
means) that membrane filtration in
combination with disinfection treatment
consistently achieves 3 log removal and/
or inactivation of Giardia lamblia cysts,
4 log removal and/or inactivation of
viruses, and 2 log removal of
Cryptosporidium oocysts. For each
approval, the State will set turbidity
performance requirements that the
system must meet at least 95 percent of
the time and that the system may not
exceed at any time at a level that
consistently achieves 3 log removal and/
or inactivation of Giardia lamblia cysts,
4 log removal and/or inactivation of
viruses, and 2 log removal of
Cryptosporidium oocysts.
Systems utilizing slow sand or
diatomaceous earth filtration must
continue to meet the combined filter
effluent limits established for these
technologies under the SWTR (found in
§ 141.73 (b) and (c)). Namely, the
turbidity level of representative samples
of a system's filtered water must be less
than or equal to 1 NTU in at least 95
percent of the measurements taken each
month and the turbidity level of
representative samples of a system's
filtered water must at no time exceed 5
NTU.
For all other alternative filtration
technologies (those other than
conventional, direct, slow sand,
diatomaceous earth, or membrane),
public water systems must demonstrate
to the State for purposes of approval
(using pilot plant studies or other
means), that the alternative filtration
technology in combination with
disinfection treatment, consistently
achieves 3 log removal and/or
inactivation of Giardia lamblia cysts, 4
log removal and/or inactivation of
viruses, and 2 log removal of
Cryptosporidium oocysts. For each
approval, the State will set turbidity
performance requirements that the
system must meet at least 95 percent of
the time and that the system may not
exceed at any time at a level that
consistently achieves 3 log removal and/
or inactivation of Giardia lamblia cysts,
4 log removal and/or inactivation of
viruses, and 2 log removal of
Cryptosporidium oocysts.
iv. Request for Comments
EPA solicits comment on the proposal
to require systems to meet the proposed
combined filter effluent turbidity
requirements. Additionally, EPA solicits
comment on the following:
• The ability of package plants and/
or other unique conventional and/or
direct systems to meet the combined
filter effluent requirements;
• Microbial attachment to particulate
material or inert substances in water
systems may have the effect of
providing "shelter" to microbes by
reducing their exposure to disinfectants
(USEPA, 1999e). While inactivation of
Cryptosporidium is not a consideration
of this rule, should maximum combined
filter effluent limits for slow sand and
diatomaceous earth filtration systems be
lowered to 1 or 2 NTU and/or 95th
percentile requirements lowered to 0.3
NTU to minimize the ability of turbidity
particles to "shelter" Cryptosporidium
oocysts?
• Systems which practice enhanced
coagulation may produce higher
turbidity effluent because of the process.
Should such systems be allowed to
apply to the State for alternative
exceedance levels similar to the
provisions contained in the rule for
systems which practice lime softening?
• Issues specific to small systems
regarding the proposed combined filter
effluent requirements;
• Establishment of turbidity limits for
alternative filtration technologies;
• Allowance of a demonstration to
establish site specific limits in lieu of
generic turbidity limits, including
components of such demonstration; and
• The number of small membrane
systems employed throughout the
country. *
The Agency also requests comment on
establishment of turbidity limits for
membrane systems. While integrity of
membranes provides the clearest
understanding of the effectiveness of
membranes, turbidity has been utilized
as an indicator of performance (and
corresponding Cryptosporidium log
removal) for all filtration technologies.
EPA solicits comment on modifying the
requirements for membrane filters to
meet integrity testing, as approved by
the State and with a frequency approved
by the State.
b. Individual Filter Turbidity
i. Overview and Purpose
During development of the IESWTR,
it was recognized that performance of
individual filters within a plant were of
paramount importance to producing
low-turbidity water. Two important
concepts regarding individual filters
were discussed. First, it was recognized
that poor performance (and potential
pathogen breakthrough) of one filter
could be masked by optimal
performance in other filters, with no
discernable rise in combined filter
effluent turbidity. Second, it was noted
that individual filters are susceptible to
turbidity spikes (of short duration)
which would not be captured by four-
hour combined filter effluent
measurements. To address the
shortcomings associated with individual
filters, EPA established individual filter
monitoring requirements in the
IESWTR. For the reasons discussed
below, the Agency believes it
appropriate and necessary to extend
individual filter monitoring
requirements to systems serving
populations fewer than 10,000 in the
LT1FBR.
ii. Data
EPA believes that the support and
underlying principles regarding the
IESWTR individual filter monitoring
requirements are also applicable for the
LTlFBR. The Agency has estimated that
5,897 conventional and direct filtration
systems will be subject to today's
proposed individual filter turbidity
requirements. Information regarding this
estimate is found in Section IV.A.2.a of
today's proposal. The Agency has
analyzed information regarding
turbidity spikes and filter masking
which are presented next.
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Federal Register/Vol. 65, No. 69/Monday, April 10, 2000/Proposed Rules
19073
Turbidity Spikes
During a turbidity spike, significant
amounts of particulate matter (including
Cryptosporidium oocysts, if present)
may pass through the filter. Various
factors affect the duration and
amplitude of filter spikes, including
sudden changes to the flow rate through
the filter, treatment of the filter
backwash water, filter-to-waste
capability, and site-specific water
quality conditions. Recent experiments
have suggest that surging has a
significant effect on rapid sand filtration
performance (Glasgow and Wheatley,
1998). An example filter profile
depicting turbidity spikes is shown in
Figure IV.4.
BILLING CODE 6560-50-P
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Federal Register/Vol. 65, No, 69/Monday, April 10, 2000/Proposed Rules
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Federal Register/Vol. 65, No. 69/Monday, April 10, 2000/Proposed Rules
19075
Studies considered by both EPA and
the M-DBP Advisory Committee noted
that the greatest potential for a peak in
turbidity (and thus, pathogen
breakthrough) is near the beginning of
the filter run after filter backwash or
start up of operation (Amirtharajah,
1988; Bucklin, et al. 1988; Cleasby,
1990; and Hall and Croll, 1996). This
phenomenon is depicted in Figure IV.4.
Turbidity spikes also may occur for a
variety of other reasons. These include:
• Outages or maintenance activities at
processes within the treatment train;
• Coagulant feed pump or equipment
failure;
• Filters being run at significantly
higher loading rates than approved;
• Disruption in filter media;
• Excessive or insufficient coagulant
dosage; and
• Hydraulic surges due to pump
changes or other filters being brought
on/off-line.
A recent study was completed which
evaluated particle removal by filtration
throughout the country. While the
emphasis of this study was particle
counting and removal, fifty-two of the
100 plants surveyed were also surveyed .
for turbidity with on-line turbidimeters. :
While all of the plants were able to meet
0.5 NTU 95 percent of the time, it was
noted that there was a significant
occurrence of spikes during the filter
runs. These were determined to be a
major source of raising the 95th
percentile value for most of the filter
runs. (McTigue et al. 1998)
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BILLING CODE B580-50-C
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Masking of Filter Performance
Combined Filter Effluent monitoring
can mask poor performance of
individual filters which, may allow
passage of particulates (including
Cryptosporidium oocysts). One poorly
performing filter, can be effectively
"masked" by other well operated filters
because water from each of the filters is
combined before an effluent turbidity
measurement is taken. The following
example illustrates this phenomenon.
The fictitious City of "Smithville"
(depicted in Figure IV.6) operates a
conventional filtration plant with four
rapid granular niters as shown below.
Filter number 1 has significant problems
because the depth and placement of the
media are contributing to elevated
turbidities. Filters 2, 3, and 4 do not
have these problems and are operating
properly.
BILLING CODE 6560-50-P
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BILUNG CODE 6560-50-C
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19084
Federal Register/Vol. 65, No. 69/Monday, April 10, 2000/Proposed Rules
Turbidity measurements taken at the
clearwell indicate 0.3 NTU. Filter 4
produces water with a turbidity of 0.08
NTU, Filter 3 a turbidity of 0.2 NTU,
Filter 2 a'turbidity of 0.1 NTU, and
Filter 1 a turbidity of 0.9 NTU. Each
filter contributes an equal proportion of
water, but each is operating at different
turbidity levels which contributes to the
combined filter effluent of 0.32 NTU.
([0.08+0.2+0.1+0.91+4 = 0.32 NTU)
As discussed previously in Section
IV.2.a, the Agency believes that a system
must meet 0.3 NTU 95 percent of the
time an appropriate treatment technique
requirement that assures an increased
level of Cryptosporidium removal.
While the fictitious system described
above would barely meet the required
CFE turbidity, it is entirely possible that
they would not be achieving an overall
2 log removal of Cryptosporidium with
one filter achieving considerably less
than 2-log removal. This issue
highlights the importance of
understanding the performance of
individual filters relative to overall
plant performance.
iii. Proposed Requirements
Today's proposed rule establishes an
individual filter turbidity requirement
which applies to all surface water and
GWUDI systems using filtration and
which serve populations fewer than
10,000 and utilize direct or
conventional filtration. In developing
this requirement, the Agency evaluated
several alternatives (A, B and C) in an
attempt to reduce the burden faced by
small systems while still providing: (1)
A comparable level of public health
protection as that afforded to systems
serving 10,000 or more people and (2)
an early-warning tool systems can use to
detect and correct problems with filters.
Alternative A
The first alternative considered by the
Agency was requiring direct and
conventional filtration systems serving
populations fewer than 10,000 to meet
the same requirements as established for
systems serving 10,000 or more people.
This alternative would require that all
conventional and direct filtration
systems must conduct continuous
monitoring of turbidity (one turbidity
measurement every 15 minutes) for each
individual filter. Systems must provide
an exceptions report to the State as part
of the existing combined filter effluent
reporting process for any of the
following circumstances:
(1) Any individual filter with a
turbidity level greater than 1.0 NTU
based on two consecutive measurements
fifteen minutes apart;
(2) Any individual filter with a
turbidity greater than 0.5 NTU at the
end of the first four hours of filter
operation based on two consecutive
measurements fifteen minutes apart;
(3) Any individual filter with
turbidity levels greater than 1.0 NTU
based on two consecutive measurements
fifteen minutes apart at any time in each
of three consecutive months (the system
must, in addition to filing an exceptions
report, conduct a self-assessment of the
filter); and
(4) Any individual filter with
turbidity levels greater than 2.0 NTU
based on two consecutive measurements
fifteen minutes apart at any time in each
of two consecutive months (the system
must file an exceptions report and must
arrange for a comprehensive
performance evaluation (CPE) to be
conducted by the State or a third party
approved by the State).
Under the first two circumstances
identified, a system must produce a
filter profile if no obvious reason for the
abnormal filter performance can be
identified.
Alternative B
The second alternative considered by
the Agency represents a slight
modification from the individual filter
monitoring requirements of large
systems. The 0.5 NTU exceptions report
trigger would be omitted in an effort to
reduce the burden associated with daily
data evaluation. Additionally, the filter
profile requirement would be removed.
Requirement language was slightly
modified in an effort to simplify the
requirement for small system operators.
This alternative would still require that
all conventional and direct nitration
systems conduct continuous monitoring
(one turbidity measurement every 15
minutes) for each individual filter, but
includes the following three
requirements:
(1) A system must provide an
exceptions report to the State as part of
the existing combined effluent reporting
process if any individual filter turbidity
measurement exceeds 1.0 NTU (unless
the system can show that the next
reading is less than 1.0 NTU);
(2) If a system is required to submit
an exceptions report for the same filter
in three consecutive months, the system
must conduct a self-assessment of the
filter.
(3) If a system is required to submit
an exceptions report for the same filter
in two consecutive months which
contains an exceedance of 2.0 NTU by
the same filter, the system must arrange
for a CPE to be conducted by the State
or a third party approved by the State.
Alternative C
The third alternative considered by
the Agency would include new triggers
for reporting and follow-up action in an
effort to reduce the daily burden
associated with data review. This
alternative would still require that all
conventional and direct filtration
systems must conduct continuous
monitoring (one turbidity measurement
every 15 minutes) for each individual
filter, but would include the following
three requirements:
(1) A system must provide an
exceptions report to the State as part of
the existing combined effluent reporting
process if filter samples exceed 0.5 NTU
in at least 5 percent of the
measurements taken each month and/or
any individual filter measurement
exceeds 2.0 NTU (unless the system can
show that the following reading was <
2.0 NTU).
(2) If a system is required to submit
an exceptions report for the same filter
in three consecutive months the system
must conduct a self-assessment of the
filter.
(3) If a system is required to submit
an exceptions report for the same filter
in two consecutive months which
contains an exceedance of 2.0 NTU by
the same filter, the system must arrange
for a CPE to be conducted by the State
or a third party approved by the State.
For all three alternatives the
requirements regarding self assessments
and CPEs are the same. If a CPE is
required, the system must arrange for
the State or a third party approved by
the State to conduct the CPE no later
than 30 days following the exceedance.
The CPE must be completed and
submitted to the State no later than 90
days following the exceedance which
triggered the CPE. If a self-assessment is
required it must take place within 14
days of the exceedance and the system
must report to the State that the self-
assessment was conducted. The self
assessment must consist of at least the
following components:
• assessment of filter performance;
• development of a filter profile;
• identification and prioritization of
factors limiting filter performance;
• assessment of the applicability of
corrections; and
• preparation of a filter self
assessment report.
In considering each of the above
alternatives, the Agency attempted to
reduce the burden faced by small
systems. Each of the three alternatives
was judged to provide levels of public
health protection comparable to those in
the IESWTR for large systems.
Alternative A, because it contains the
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19085
same requirements as EESWTR, was
expected to afford the same level of
public health protection. Alternative B,
(which removes the four-hour 0.5 MTU
trigger and the filter profile
requirement) was expected to afford
comparable health protection because
the core components which provide the
overwhelming majority of the public
health protection (monitoring
frequency, trigger which requires
follow-up action, and the follow-up
actions) are the same as the IESWTR.
Alternative C was expected to provide
comparable health protection because
follow-up action is the same as under
the IESWTR and a 0.5 NTU 95percent
percentile trigger was expected to
identify the same systems which the
triggers established under the IESWTR
would identify. All three were also
considered useful diagnostic tools for
small systems to evaluate the
performance of filters and correct
problems before follow-up action was
necessary. The first alternative was
viewed as significantly more
challenging to implement and
burdensome for smaller systems due to
the amount of required daily data
review. This evaluation was also echoed
by small entity representatives during
the Agency's SBREFA process as well as
stakeholders at each of the public
meetings held to discuss issues related
to today's proposed rule. While
Alternative C reduced burden associated
with daily data review, it would
institute a very different trigger for small
systems than established by the EESWTR
for large systems. This was viewed as
problematic by several stakeholders
who stressed the importance of
maintaining similar requirements in
order to limit transactional costs and
additional State burden. Therefore, the
Agency is proposing Alternative B as
described above, which allows operators
to expend less time to evaluate their
turbidity data. Alternative B maintains a
comparable level of public health
protection as those afforded large
systems, reduces much of the burden
associated with daily data collection
and review (removing the requirement
to conduct a filter profile allows systems
to review data once a week instead of
daily if they so choose), yet still serves
as a self-diagnostic tool for operators
and provides the mechanism for State
follow-up when significant performance
problems exist.
iv. Request for Comments
The individual filter monitoring
provisions represent a challenging
opportunity to provide systems with a
useful tool for assessing filters and
correcting problems before State
intervention is necessary or combined
filter turbidity is affected and treatment
technique violations occur. The Agency
is actively seeking comment on this
provision. Because of the complexity of
this provision, specific requests for
comment have been broken down into
five distinct areas.
Comments on the Alternatives
EPA requests comment on today's
proposed individual filter requirement
and each of the alternatives as well as
additional alternatives for this provision
such as establishing a different
frequency for individual filter
monitoring (e.g., 60 minute or 30 minute
increments). The Agency also seeks
comment or information on:
• Tools and or guidance which would
be useful and necessary in order to
educate operators on how to comply
with individual filter provisions and
perform any necessary calculations;
• Data correlating individual filter
performance relative to combined filter
effluent;
• Contributing factors to turbidity
spikes associated with reduced filter
performance;
• Practices which contribute to poor
individual filter performance and filter
spikes; and
• Any additional concerns with
individual filter performance.
Modifications to the Alternatives
The Agency also seeks comment on a
variety of proposed modifications to the
individual filter monitoring alternatives
discussed which could be incorporated
in order to better address the concerns
and realities of small surface water
systems. These modifications include:
• Modification of the alternatives to
include a provision which would
require systems which do not staff the
plant during all hours of operation, to
utilize an alarm/phone system to alert
off-site operators of significantly
elevated turbidity levels and poor
individual filter performance;
• A modification to allow
conventional and direct filtration
systems with either 2—3 or less filters to
sample combined filter effluent -.
continuously (every 15 minutes) in lieu
of monitoring individual filter turbidity.
This modification would reduce the
data collection/analysis burden for the
smallest systems while not
compromising the level of public health
protection; •:
• A modification to lengthen the
period of time (120 days or a period of
time established by the State but not to
exceed 120 days) for completion of the
CPE and/or a modification to lengthen
the requirement that a CPE must be
conducted no later than 60 or 90 days
following the exceedance; and
• A modification to require systems
to notify the State within 24 hours of
triggering the CPE or IFA. This would
inform States sooner so they can begin
to work with systems to address
performance of filters and conduct CPEs
and IF As as necessary.
Establishment of Subcategories
The Agency is also evaluating the
need to establish subcategories in the
final rule for individual filter
monitoring/reporting. EPA is currently
considering these three categories:
1. Systems serving populations of
3,300 or more persons;
2. Systems with more than 2 filters,
but less than 3,300 persons; and
3. Systems with 2 or fewer filters
serving populations fewer than 3,300
persons. ;
Individual filter monitoring
requirements would also be based on
these subcategories. Systems serving
3,300 or greater would be required to
meet the same individual turbidity
requirements as the IESWTR
(Alternative A as described above).
Systems serving fewer than 3,300 but
using more than 2 filters would be
required to meet a modified version of
the IESWTR individual filter
requirements (Alternative B as
described above). Systems serving fewer
than 3,300 and using 2 or fewer filters
would continue to monitor and report
only combined filter effluent turbidity at
an increased frequency (once every 15
minutes, 30 minutes, or one hour).
Input and or comment on cut-offs for
subcategories and how to apply
subcategories to Alternatives is
requested. The Agency would also like
to take comment on additional strategies
to tailor individual filter monitoring for
the smallest systems while continuing
to maintain an adequate level of public
health protection. Such possible
strategies include:
• Since small systems are often
understaffed one approach would
require those systems utilizing only two
or fewer filters to utilize, maintain, and
continually operate an alarm/phone
system during all hours of operation,
which alert off-site operators of
significantly elevated turbidity levels
and poor individual filter performance
and/or automatically shuts the system
down if turbidity levels exceed a
specified performance level. This
modification would be in addition to
the proposed requirements.
• Establishing a more general
modification which would require
systems which do not staff the plant
during all hours of operation to utilize
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Federal Register/Vol. 65, No. 69/Monday, April 10, 2000/Proposed Rules
an alarm/phone system to alert off-site
operators of significantly elevated
turbidity levels and poor individual
filter performance, and/or to
automatically shut the system down if
turbidity levels exceed a specified
performance level.
• If systems with 2 or fewer filters is
allowed to sample combined filter
effluent in lieu of individual filter
effluent with a frequency of a reading
every hour and combined filter effluent
turbidity exceeds 0.5 NTU, should the
system be required to take grab samples
of individual filter turbidity for all
filters every 15 minutes until the results
of those samples are lower than 0.5
NTU?
Reliability
Maintaining reliable performance at
systems using filtration requires that the
filters be examined at intervals to
determine if problems are developing.
This can mean that a filter must go off-
line for replacement or upgrades of
media, underdrains, backwash lines etc.
In order to provide adequate public
health protection at small systems, the
lack of duplicate units can be a problem.
EPA is considering requiring any system
with only one filter to install an
additional filter. The schedule would be
set by the primacy agency, but the filter
would have to be installed no later than
6 years after promulgation. EPA is
requesting comment on this potential
requirement.
Data Gathering Recordkeeping and
Reporting
The Agency is evaluating data
gathering/reporting requirements for
systems. A system collecting data at a
frequency of once every 15 minutes,
(and operating) 24 hours a day, would
record approximately 2800 data points
for each filter throughout the course of
the month. Although the smallest
systems in operation today routinely
operate on the average of 4 to 12 hours
a day (resulting in 480 to 1400 data
points per filter), these systems do not
typically use sophisticated data
recording systems such as SCADAs. The
lack of modern equipment at small
systems may result in difficulty with
retrieving and analyzing data for
reporting purposes. While the Agency
intends to issue guidance targeted at
aiding these systems with the data
gathering requirements, EPA is also
seeking feedback on a modification to
the frequency of data gathering required
under each of the aforementioned
options. Specifically, the Agency would
like to request comment on modifying
the frequency for systems serving fewer
than 3,300 to continuous monitoring on
a 30 or 60 minute basis. EPA also
requests comment on the availability
and practicality of data systems that
would allow small systems, State
inspectors, and technical assistance
providers to use individual filter
turbidity data to improve performance,
perform filter analysis, conduct
individual filter self assessments, etc.
The Agency is interested in specific
practical combinations of data
recorders, charts, hand written
recordings from turbidimeters, that
would accomplish this.
Failure of Continuous Turbidity
Monitoring
Under today's proposed rule, the
Agency requires that if there is a failure
in the continuous turbidity monitoring
equipment, the system must conduct
grab sampling every four hours in lieu
of continuous monitoring until the
turbidimeter is back on-line. A system
has five working days to resume
continuous monitoring before a
violation is incurred. EPA would like to
solicit comment on modifying this
component to require systems to take
grab samples at an increased frequency,
specifically every 30 minutes, 1 hour, or
2 hours.
B. Disinfection Benchmarking
Requirements
Small systems will be required to
comply with the Stage 1 Disinfection
Byproduct Rule (Stage 1 DBPR) in the
first calendar quarter of 2004. The Stage
1 DBPR set Maximum Contaminant
Levels (MCLs) for Total
Trihalomethanes (chloroform,
bromodichloromethane,
chlorodibromomethane, and
bromoform), and five Haloacetic Acids
(i.e., the sum of the concentrations of
mono-, di-, and trichloroacetic acids and
mono- and dibromoacetic acids.) The
LTlFBR follows the principles set forth
in earlier FACA negotiations, 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 MCL's for
TTHM and HAAS set forth in Stage 1
DBPR. The disinfection benchmarking
requirements are designed to ensure that
risk from one contaminant is not
increased while risk from another
contaminant is decreased.
The Stage 1 DBPR was promulgated
because disinfectants such as chlorine
can react with natural organic and
inorganic matter in source water and
distribution systems to form
disinfection byproducts (DBFs). Results
from toxicology studies have shown
several DBFs (e.g.,
bromodichloromethane, bromoform,
chloroform, dichloroacetic acid, and
bromate) to potentially cause cancer in
laboratory animals. Other DBFs (e.g.,
certain haloacetic acids) have been
shown to cause adverse reproductive or
developmental effects in laboratory
animals. Concern about these health
effects may cause public water utilities
to consider altering their disinfection
practices to minimize health risks to
consumers.
A fundamental principle, therefore, of
the 1992-1993 regulatory negotiation
reflected in the 1994 proposal for the
IESWTR was that new standards for
control of DBFs must not result in
significant increases in microbial risk.
This principle was also one of the
underlying premises of the 1997 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
MCL's for TTHM and HAAS set forth in
Stage 1 DBPR. The Advisory Committee
reached agreement on the use of
microbial profiling and benchmarking
as a process by which a PWS and the
State, working together, could assure
that there would be no significant
reduction in microbial protection as the
result of modifying disinfection
practices in order to comply with Stage
1 DBPR.
The process established under the
IESWTR has three components: (1)
Applicability Monitoring; (2)
Disinfection Profiling; and (3)
Disinfection Benchmarking. These
components have the following three
goals respectively: (1) determine which
systems have annual average TTHM and
HAAS levels close enough to the MCL
(e.g., 80 percent of the MCL) that they
may need to consider altering their
disinfection practices to comply with
Stage 1 DBPR; (2) those systems that
have TTHM and HAA5 levels of at least
80 percent of the MCLs must develop a
baseline of current microbial
inactivation over the period of 1 year;
and (3) determine the benchmark, or the
month with the lowest average level of
microbial inactivation, which becomes
the critical period for that year.
The aforementioned components were
applied to systems serving 10,000 or
more people in the IESWTR and were
carried out sequentially. In response to
concerns about early implementation
(any requirement which would require
action prior to 2 years after the
promulgation date of the rule), the
Agency is considering modifying the
IESWTR approach for small systems, as
described in the following section.
Additionally, the specific provisions
have been modified to take into account
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19087
specific needs of small systems. EPA's
goal in developing these requirements is
to recognize the specific needs of small
system and States, while providing
small systems with a useful means of
ensuring that existing microbial
protection must not be significantly
reduced or undercut as a result of
systems taking the necessary steps to
comply with the MCL's for TTHM and
HAAS set forth in Stage 1 DBPR.
The description of the disinfection
benchmarking components of today's
proposed rule will be broken into the
three segments: (1) Applicability
Monitoring; (2) Disinfection Profiling;
and (3) Disinfection Benchmarking.
Each section will provide an overview
and purpose, data, a description of the
proposed requirements, and request for
comment.
1. Applicability Monitoring
a. Overview and Purpose
The purpose of the TTHM and HAAS
applicability monitoring is to serve as
an indicator for systems that are likely
to consider making changes to tiieir
disinfection practices in order to
comply with the Stage 1 DBPR. TTHM
samples which equal or exceed 0.064
mg/L and/or HAAS samples equal or
exceed 0.048 mg/L (80 percent of their
respective MCLs) represent DBF levels
of concern. Systems with TTHM or
HAAS levels exceeding 80 percent of
the respective MCLs may consider
changing their disinfection practice in
order to comply with the Stage 1 DBPR.
b. Data
In 1987, EPA established monitoring
requirements for 51 unregulated
synthetic organic chemicals.
Subsequently, an additional 113
unregulated contaminants were added
to the monitoring requirements.
Information on TTHMs has become
available from the first round of
monitoring conducted by systems
serving fewer than 10,000 people.
Preliminary analysis of the data from
the Unregulated Contaminant
Information System (URCIS, Data)
suggest that roughly 12 percent of
systems serving fewer than 10,000
would exceed 64 |i/L or 80 percent of
the MCL for TTHM (Table IV.7). This
number is presented only as an
indicator, as it represents samples taken
at the entrance to distribution systems.
In general, TTHMs and HAASs tend to
increase with time as water travels
through the distribution system. The
Stage 1 Disinfection Byproducts Rule •
estimated 20 percent of systems serving
fewer than 10,000 would exceed 80
percent of the MCLs for either TTHMs
or HAASs or both. EPA is working to
improve the knowledge of TTHM and
HAAS formation kinetics in the
distribution systems for systems serving
fewer than 10,000 people. EPA is
currently developing a model to predict
the formation of TTHM and HAAS in
the distribution system based on
operational measurements. This model
is not yet available. In order to develop
a better estimate of the percent of small
systems that would be triggered into the
profiling requirements (i.e., develop a
profile of microbial inactivation over a
period of 1 year) EPA is considering the
following method:
• Use URCIS data to show how many
systems serving 10,000 or more people
have TTHM levels at or above 0.064 mg/
L;
• Compare those values to the data
received from the Information
Collection Rule for TTHM average
values taken at representative points in
the distribution system;
• Determine the mathematical factor
by which the two values differ; and
• Apply that factor to the URCIS data
for systems serving fewer than 10,000
people to estimate the percent of those
systems that would have TTHM values ,
at or above 0.064mg/L as an average of
values taken at representative points in
the distribution system.
TABLE IV.7.—TTHM LEVELS AT SMALL SURFACE SYSTEMS
[Data from Unregulated Contaminant Database, 1987-921]
System size (population served)
<500
501-1,000
1,001-3.300
3,301-10,000
Total
Total num-
ber of sys-
tems
74
44
114
116
348
Number of
systems w/
ave. TTHM
> 64 ug/L
(80 % of
MCL)
n in0/*}
6 (136%)
12 (10 5%)
OC /O-l f!0/\
43 (12.4%)
!
Maximum
level of ave.
TTHM
(US/L) :
cc
999
179
97Q
279
1ln Unregulated Contaminant Database (1987-1992), there are ten States (i.e., CA, DE, IN, MD, Ml, MO, NC, NY, PR, WV). However only
eight of them can be identified with the data of both population and TTHM for systems serving fewer than 10,000 people (See next page).
The Agency requests comment on this
approach to estimating TTHM levels in
the distribution system based on TTHM
levels at the entry point to the
distribution system. The Agency also
requests comment on the relationship of
HAAS formation relative to TTHM
formation in the distribution system.
Specifically, is there data to support the
hypothesis that HAASs do not peak at
the same point in the distribution
system as TTHMs?
The Agency also received two full
years of TTHM data for seventy-four
systems in the State of Missouri
(Missouri, 1998). This data consisted of
quarterly TTHM data, which was
converted into an annual average. The
data (presented in Table IV.8)
demonstrates a very different picture
than that displayed by the URCIS data
described above. In 1996, 88 percent of
the systems exceeded 64 ug/L, while in
1997, 85 percent exceeded 64 Ug/L.
Figure IV.7 graphically displays this
data set.
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TABLE IV.8—TTHM LEVELS AT SMALL SURFACE SYSTEMS IN THE STATE OF MISSOURI
[State of Missouri, 1996, 1997]
1
Year
1996
1997
All years
Total num-
ber of sys-
tems
74
75
149
Number of
systems w/
ave. TTHM
> 64 ug/L
(80 percent
of MCL)
65 (88%)
64 (85%)
129 (87%)
Maximum
Level of
Ave. TTHM
(ug/L)
276
251
276
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shown in Table IV. 8 is similar to the
methodology required under the Stage 1
DBPR.
c. Proposed Requirements
EPA considered four alternatives for
systems to use TTHM and HAAS data to
determine which systems whether they
would be required to develop a
disinfection profile. In today's proposed
rule, EPA is proposing Alternative 4.
Alternative 1
The IESWTR required that systems
monitor for TTHMs at four points in the
distribution system each quarter. At
least one of those samples must be taken
at a point which represents the
maximum residence time of the water in
the system. The remaining three must be
taken at representative locations in the
distribution system, taking into account
number of persons served, different
sources of water and different treatment
methods employed. The results of all
analyses per quarter are averaged and
reported to the State.
EPA considered applying this
alternative to systems serving fewer
than 10,000 people and requested input
from small system operators and other
interested parties, including the public.
Based on the feedback EPA received,
two other alternatives were developed
for consideration (listed as Alternatives
2 and 3).
Alternative 2
EPA considered requiring systems
serving fewer than 10,000 people to
monitor for TTHM and HAAS at the
point of maximum residence time
according to the following schedule:
• No less than once per quarter per
treatment plant operated for systems
serving populations between 500 and
10,000 persons; and no less than once
per year per treatment plant during the
month of warmest water temperature for
systems serving populations less than
500. If systems wish to take additional
samples, however, they would be
permitted to do so.
• Systems may consult with States
and elect not to perform TTHM and
HAAS monitoring and proceed directly
with the development of a disinfection
profile.
This alternative provides an
applicability monitoring frequency
identical to the DBF monitoring
frequency under the Stage 1 DBPR that
systems will have to comply with in
2004. In addition, it allows systems the
flexibility to skip TTHM and HAAS
monitoring completely, pending State
approval, and begin profiling
immediately.
Alternative 3
EPA considered requiring all systems
serving fewer than 10,000 people to
monitor once per year per system during
the month of warmest water
temperature of 2002 and at the point of
maximum residence time.
During the SBREFA process and
during stakeholder meetings, EPA
received some positive comments
regarding Alternative 3 as the least
burdensome approach. Other
stakeholders, however, pointed out that
Alternative 3 does not allow systems to
measure seasonal variation as is done in
Alternative 2 for systems serving
populations between 500 and 10,000.
Several stakeholders agreed that despite
the costs, the information obtained from
applicability monitoring will be useful.
EPA agrees that it is valuable to systems
to monitor and understand the seasonal
variation in TTHM and HAAS values,
however, EPA has determined that
requiring a" full year of monitoring may
place an excessive burden on both
States and systems. In order to complete
a full year of monitoring and another
full year of disinfection data gathering,
systems would have to start TTHM and
HAAS monitoring January of 2002.
Under SDWA, States have two years
to develop their own regulations as part
of their primacy requirements, EPA
recognized that requiring Applicability
Monitoring during this period would
pose a burden on States. In response to
these concerns, the Agency developed a
new alternative, described in the
following paragraph.
Alternative 4
Applicability Monitoring is optional
and not a requirement under today's
proposed rule. If a system has TTHM
and HAAS data taken during the month
of warmest water temperature (from
1998-2002) and taken at the point of
maximum residence time, they may
submit this data to the State prior to
[DATE 2 YEARS AFTER PUBLICATION
OF FINAL RULE]. If the data shows
TTHM and HAAS levels less than 80
percent of the MCLs, the system does
not have to develop a disinfection
profile. If the data shows TTHM and
HAAS levels at or above 80 percent of
the MCLs, the system would be required
to develop a disinfection profile in 2003
as described later in section IV.B.2. If
the system does not have, or does not
gather TTHM and HAAS data during the
month of warmest water temperature
and at the point of maximum residence
tune in the distribution system as
described, then the system would
automatically be required to develop a
disinfection profile starting January 1 of
2003. This option still provides systems
with the necessary tools for assessing
potential changes to their disinfection
practice, (i.e. the generation of the
profile), while not forcing States to pass
their primacy regulations, contact all
small systems within their jurisdiction,
and set up TTHM and HAAS monitoring
all within the first year after
promulgation of this rule. Systems will
still be able to ensure public health
protection by having the disinfection
profile when monitoring under Stage 1
DBPR takes effect. It should be noted
that EPA estimates the cost for
applicability monitoring (as described
in Alternative 4) and disinfection
profiling (as described in Alternative 3
in Section IV.B.2.C of this preamble) are
roughly equivalent. EPA anticipates that
systems with known low levels of TOC
may opt to conduct the applicability
monitoring while the remaining systems
will develop a disinfection profile.
d. Request for Comment
EPA requests comment on the
proposed requirement, other
alternatives listed, or other alternatives
that have not yet been raised for
consideration. The Agency also requests
comment on approaches for determining
the percent of systems that would be
affected by this requirement.
Specifically:
• With respect to Alternative 4, the
Agency requests comment on
approaches for determining the percent
of systems that might demonstrate
TTHM and HAAS levels less than 80
percent of their respective MCLs and
would therefore not develop a
disinfection profile.
• The Agency requests additional
information (similar to the State of
Missouri data discussed previously) on
the current levels of TTHM and HAASs
in the distribution systems of systems
serving fewer than 10,000 people.
• The Agency requests comment on
developing a TTHM and HAAS
monitoring scheme during die winter
months as opposed to the current
monitoring scheme based on the highest
TTHM/HAA5 formation potential
during the month of warmest water
temperature. If a relationship can be
established, and shown to be consistent
through geographical variations, EPA
would consider modifying an
alternative so that applicability
monitoring would occur during the 1st
quarter of 2003.
• The Agency requests comment on
modifying Alternative 3, to require
systems to begin monitor for TTHMs
and HAASs during the warmest water
temperature month of 2003. The results
of this monitoring would be used to
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19091
determine whether a system would need
to develop a disinfection profile during
2004. This option is closer in structure
and timing to the IESWTR and has been
included for comment. It should be
noted, however, that postponing the
disinfection profile until 2004 would
prevent systems from having
inactivation data prior to their
compliance date with the Stage 1 DBPR,
possibly compromising simultaneous
compliance.
2. Disinfection Profiling
a. Overview and Purpose
The disinfection profile is a graphical
representation showing how
disinfection varies at a given plant over
time. The profile gives the plant
operator an idea of how seasonal
changes in water quality and water
demand can have a direct effect on the
level of disinfection the plant is
achieving.
The strategy of disinfection profiling
and benchmarking stemmed from data
provided to the EPA and M-DBP
Advisory Committee by PWSs and
reviewed by stakeholders. The microbial
inactivation data (expressed as logs of
Giardia lamblia inactivation) used by
the M—DBP Advisory Committee
demonstrated high variability.
Inactivation varied by several log 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, M-DBP stakeholders
developed the procedure of profiling
inactivation levels at an individual
plant over a period of at least one year,
and then establishing a benchmark of
minimum inactivation as a way to
characterize disinfection practice. This,
approach makes it possible for a plant
that may need to change its disinfection
practice in order to meet DBP MCLs to :
determine the impact the change would
have on its current level of disinfection
or inactivation and, thereby, to assure
that there is no significant increase in
microbial risk. In order to develop the
profile, a system must measure four
parameters (EPA is assuming most small
systems use chlorine as their '•
disinfection agent, and these
requirements are based on this
assumption):
(1) Disinfectant residual concentration
(C, in mg/L) before or at the first
customer and just prior to each
additional point of disinfectant
addition;
(2) Contact time (T, in minutes)
during peak flow conditions;
(3) Water temperature (°C); and
(4) pH.
Systems convert this operational data
to a number representing log
inactivation values for Giardia by using
tables provided by EPA. Systems graph
this information over time to develop a
profile of their microbial inactivation.
EPA will prepare guidance specifically
developed for small systems to assist in
the development of the disinfection
profile. Several spreadsheets and simple
programs are currently available to aid
in calculating microbial inactivation
and the Agency intends to make such
spreadsheets available in guidance.
b. Data
Figure IV.8a depicts a hypothetical
disinfection profile showing seasonal
variation in microbial inactivation.
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c. Proposed Requirements
EPA considered four alternatives for
requiring systems to develop the
disinfection profile.
Alternative 1
The IESWTR requires systems serving
10,000 or more persons to measure the
four parameters described above and
develop a profile of microbial
inactivation on a daily basis. EPA
considered extending this requirement
to systems serving fewer than 10,000
persons and requested input from small
system operators and other interested
stakeholders including the public. EPA
received feedback that this requirement
would place too heavy of a burden on
the small system operator for at least
two reasons:
• Small system operators are not
present at the plant every day; and
• Small systems often have only one
operator at a plant who is responsible
for all aspects of maintenance,
monitoring and operation.
Alternative 2
EPA also considered not requiring the
disinfection profile at all. After
consideration of the feedback of small
system operators and other interested
stakeholders, however, EPA believes
that there is a strong benefit in the plant
operator knowing the level of microbial
inactivation, and that the principles
developed during the regulation
negotiation and Federal Advisory
Committee prior to promulgation of the
lESVVTR could be applied to small
systems for the purpose of public health
protection. Recognizing the potential
burdens the profiling procedures placed
on small systems, EPA considered two
additional alternatives.
Alternative 3
EPA considered requiring all systems
serving fewer than 10,000 persons, to
develop a disinfection profile based on
weekly measurements for one year
during or prior to 2003. A system with
TTHM and HAAS levels less than 80
percent of the MCLs (ba.sed on either
required or optional monitoring as
described in section IV.B.l) would not
be required to conduct disinfection
profiling. EPA believes this alternative
would save the operator time (in
comparison to Alternative 1), and still
provide information on seasonal
variation over the period of one year.
Alternative 4
Finally, EPA considered a monitoring
requirement only during a one month
critical monitoring period to be
determined by the State. In general,
colder temperatures reduce disinfection
efficiency. For systems in warmer :
climates, or climates that do not change
very much during the course of the year,
the State would identify other critical
periods or conditions. This alternative
reduces the number of times the
operator has to calculate the microbial ;
inactivation.
EPA considered all of the above
alternatives, and in today's proposed
rule, EPA is proposing Alternative 3.
First, this alternative does not require
systems to begin monitoring before
States have two years to develop their
regulations as part of primacy
requirements. Given early
implementation concerns, the timing of
this alternative appears to be the most
appropriate in balancing early
implementation issues with the need for
systems to prepare for implementation ,
of the Stage 1 DBPR and ensuring
adequate and effective microbial
protection. Second, it allows systems
and States which have been proactive in
conducting applicability monitoring to
reduce costs for those systems which
can demonstrate low TTHM and HAAS
levels. Third, this alternative allows
systems and States the opportunity to
understand seasonal variability in
microbial disinfection. Finally, this
alternative takes into account the
flexibility needed by the smallest
systems while maintaining comparable
levels of public health protection with
the larger systems.
Request for Comments
EPA requests comment on this
proposed requirement as well as
Alternatives 1,2, and 4. The Agency also
requests comment on a possible
modification to Alternatives 1, 3 and 4. '
Under this modification, systems
serving populations fewer than 500
would have the opportunity to apply to
the State to perform the weekly
inactivation calculation (although data
weekly data collection would still be
required). If the system decided to make
a change in disinfection practice, then
the State would assist the system with
the development of the disinfection
profile.
The Agency also requests comment on
a modification to Alternative 3 which
would require systems to develop a
disinfection profile in 2004 only if
Applicability Monitoring conducted in
2003 indicated TTHM and HAAS levels
of 80 percent or greater of the MCL. This
modification would be coupled with the
applicability monitoring modification
discussed in the previous section.
3. Disinfection Benchmarking
a. Overview and Purpose
The DBPR requires systems to meet
lower MCLs for a number of disinfection
byproducts. In order to meet these
requirements, many systems will
require changes to their current
disinfection practices. In order to ensure
that current microbial inactivation does
not fall below those levels required for
adequate Giardia and virus inactivation
as required by the SWTR, a disinfection
benchmark is necessary. A disinfection
benchmark represents the lowest
average monthly Giardia inactivation
level achieved by a system. Using this
benchmark States and systems can begin
to understand die current inactivation
achieved at the system, and estimate
how changes to disinfection practices
will affect inactivation.
b. Data
Based on the hypothetical
disinfection profile depicted in Figure
IV.8a, the benchmark, or critical period,
is the lowest level of inactivation
achieved by the system over the course
of the year. Figure IV.8b shows that this
benchmark (denoted by the dotted line)
takes place in December for the
hypothetical system.
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c. Proposed Requirements
If a system that is required to produce
a disinfection profile decides to make a
significant change in disinfection
practice after the profile is developed, it
must consult with the State and receive
approval before implementing such a
change. Significant changes in
disinfection practice are defined as: (1)
moving the point of disinfection (other
than routine seasonal changes already
approved by the State); (2) changing the
type of disinfectant; (3) changing the
disinfection process; or (4) making other
modifications designated as significant
by the State. Supporting materials for
such consultation with the State must
include a description of the proposed
change, the disinfection profile
developed under today's proposed rule
for Giardia lamblia (and, if necessary,
viruses for systems using ozone or
chlorarnines), and an analysis of how
the proposed change might affect the
current level of Giardia inactivation. In
addition, the State is required to review
disinfection profiles as part of its
periodic sanitary survey.
A log inactivation benchmark is
calculated as follows:
(I) Calculate the average log
inactivation for either each calendar
month, or critical monitoring period
(depending on final rule requirement for
the profiling provisions).
(2) Determine the calendar month
with the lowest average log inactivation;
or lowest inactivation level within the
critical monitoring period.
(3) The lowest average month, or
lowest level during the critical
monitoring period becomes the critical
measurement for that year.
(4) If acceptable data from multiple
years are available, the average of
critical periods for each year becomes
the benchmark.
(5) If only one year of data is
available, the critical period (lowest
monthly average inactivation level) for
that year is the benchmark.
d. Request for Comments
EPA has included a requirement that
State approval be obtained prior to
making a significant change to
disinfection practice. EPA requests
comment on whether the rule should
require State approval or whether only
state consultation is necessary.
EPA also requests comment on
providing systems serving fewer than
500 the option to provide raw data to
the State, and allowing the State to
determine the benchmark.
C. Additional Requirements
1. Inclusion of Cryptosporidium in
definition of GWUDI
a. Overview and Purpose
Groundwater sources are found to be
under the direct influence of surface
water (GWUDI) if they exhibit specific
traits. The SWTR defined ground waters
containing Giardia lamblia as GWUDI.
One such trait is the presence of
protozoa such as Giardia which migrate
from surface water to groundwater. The
IESWTR expanded the SWTR's
definition of GWUDI to include the
presence of Cryptosporidium. The
Agency believes it appropriate and
necessary to extend this modification of
the definition of GWUDI to systems
serving fewer than 10,000 persons.
b. Data
The Agency issued guidance on the
Microscopic Particulate Analysis (MPA)
in October 1892 as the Consensus
Method for Determining Groundwater
Under the Direct Influence of Surface ;
Water Using Microscopic Particulate
Analysis (EPA, 1992). Additional
guidance for making GWUDI
determinations is also available •;
(USEPA, 1994a,b). 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 the SWTR may also be
found in the State Sanitary Survey •
Resource Directory, jointly published in
December 1995 by EPA and the
Association of State Drinking Water
Administrators (EPA/ASDWA).
AWWARF has also published guidance
(Wilson et al., 1996).
Most recently, Hancock et al. (1997)
used the MPA test to study the
occurrence of Giardia and
Cryptosporidium in the subsurface.
They found that, in a study of 383
ground water samples, the presence of
Giardia correlated with the presence of
Cryptosporidium. The presence of both
pathogens correlated with the 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 the
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 that are calculated by ,
the MPA scoring system. An additional
two reports (SAIC 1997a and I997b)
provide data on wells with Giardia cyst .
and Cryptosporidium oocyst recovery
and concurrent MPA analysis.
c. Proposed Requirements
In today's proposed rule, EPA is
modifying the definition of GWUDI to
include Cryptosporidium for systems
serving fewer than 10,000 persons.
Under the SWTR, States were
required to determine whether systems
using ground water were using ground
water under the direct influence of
surface water (GWUDI). State
determinations were required to be
completed by June 29,1994 for CWSs
and by June 29,1999 for NCWSs. EPA
does not believe that it is necessary to
make a new determination of GWUDI
for this rule based on the addition of
Cryptosporidium to the definition of
"ground water under the direct
influence of surface water". While a
new determination is not required,
States may elect to conduct a new
analysis based on such factors as a new
land use pattern (conversion to dairy
farming, addition of septic tanks).
EPA does not believe that a new
determination is necessary because the
current screening methods appear to
adequately address the possibility of
Cryptosporidium in the ground water.
d. Request for Comments
The Agency requests comment on the
proposal to modify the definition of
GWUDI to include Cryptosporidium for
systems serving fewer than 10,000
persons.
2. Inclusion of Cryptosporidium
Watershed Requirements for Unfiltered
Systems
a. Overview and Purpose
Existing SWTR requirements for
unfiltered surface water and GWUDI
systems require these systems to
minimize the potential for source water
contamination by Giardia lamblia and
viruses. Because Cryptosporidium has
proven resistant to levels of disinfection
currently practiced at systems
throughout the country, the Agency felt
it imperative to include
Cryptosporidium in the watershed
control provisions wherever Giardia
lamblia is mentioned. The IESWTR
therefore, modified existing watershed
regulatory requirements for unfiltered
systems to include the control of
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Cryptosporidium. The Agency believes
it appropriate and necessary to extend
this requirement to systems serving
fewer than 10,000 persons.
It should be noted that today's
proposed requirements do not replace
requirements established for unfiltered
systems under the SWTR. Systems must
continue to maintain compliance with
the requirements of the SWTR for
avoidance of filtration. If an unfiltered
system fails any of the avoidance
criteria, that system must install
filtration within 18 months, regardless
of future compliance with avoidance
criteria.
EPA anticipates that in the planned
Long Term 2 Enhanced Surface Water
Treatment rule, the Agency will
reevaluate treatment requirements
necessary to manage risks posed by
Cryptosporidium and other microbial
pathogens in both filtered and unfiltered
surface water systems. In conducting
this reevaluation, EPA will utilize the
results of several large surveys,
including the Information Collection
. Rule (ICR) and ICR Supplemental
Surveys, to more fully characterize the
occurrence of waterborne pathogens, as
well as watershed and water quality
parameters which might serve as
indicators of pathogen risk level. The
LT2ESWTR will also incorporate the
results of ongoing research on removal
and inactivation efficiencies of
treatment processes, as well as studies
of pathogen health effects and disease
transmission. Promulgation of the
LT2ESWTR is currently scheduled for
May, 2002.
b. Data
Watershed control requirements were
initially established in 1989 (54 FR
27496, June 29, 1989) (EPA, 1989b), as
one of a number of preconditions that a
public water system using surface water
must meet to avoid filtration. 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 include a
characterization of the watershed
hydrology characteristics, land
ownership, and activities which may
have an advers9 effect on source water
quality, and must minimize the
potential for source water
contamination by Giardia lamblia and
viruses.
The SWTR Guidance Manual (EPA,
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
SWTR Guidance Manual recommends
that grazing and sewage discharges not
be permitted within 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. 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. The
guidance already suggests identifying
sources of microbial contamination,
other than Giardia, transmitted by
animals, and points out specifically that
Cryptosporidium may be present if there
is grazing in the watershed.
c. Proposed Requirements
In today's proposed rule, EPA is
extending the existing watershed
control regulatory requirements for
unfiltered systems serving fewer than
10,000 people to include the control of
Cryptosporidium. Cryptosporidium will
be included in the watershed control
provisions for these systems wherever
Giardia lamblia is mentioned.
Specifically, the public water system
must maintain a watershed control
program which minimizes the potential
for contamination by Giardia lamblia,
and Cryptosporidium oocysts and
viruses in the water. The State must
determine whether the watershed
control program is adequate to meet this
goal. The adequacy of a program to limit
potential contamination by Giardia
lamblia cysts, Cryptosporidium oocysts
and viruses must be based on: The
comprehensiveness of the watershed
review; the effectiveness of the system's
program to monitor and control
detrimental activities occurring in the
watershed; and the extent to which the
water system has maximized land
ownership and/or controlled land use
within the watershed.
It should be noted that unfiltered
systems must continue to maintain
compliance with the requirements of the
SWTR for avoidance of filtration. If an
unfiltered system fails any of the
avoidance criteria, that system must
install filtration within 18 months,
regardless of future compliance with
avoidance criteria.
d. Request for Comments
EPA requests comment on the
inclusion of these requirements for
unfiltered systems serving fewer than
10,000 people.
3. Requirements for Covering New
Reservoirs
a. Overview and Purpose
Open finished water reservoirs,
holding tanks, and storage tanks are
utilized by public water systems
throughout the country. Because these
reservoirs are open to the environment
and outside influences, they can be
subject to the reintroduction of
contaminants which the treatment plant
was designed to remove. The IESWTR
contains a requirement that all newly
constructed finished water reservoirs,
holding tanks, and storage tanks be
covered. The Agency believes it
appropriate and necessary to extend this
requirement to systems serving fewer
than 10,000 people.
b. Data
Existing EPA guidelines recommend
that all finished water reservoirs and
storage tanks be covered (EPA, 1991b).
The American Water Works Association
(AWWA) also has issued a policy
statement strongly supporting the
covering of reservoirs that store potable
water (AWWA, 1993). In addition, 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.
Under the IESWTR, systems serving
populations of 10,000 or greater were
prohibited from constructing uncovered
finished water reservoirs after February
16, 1999. The Agency developed an
Uncovered Finished Water Reservoirs
Guidance Manual (USEPA, 1999f)
which provides a basic understanding of
the potential sources of external
contamination in uncovered finished
water reservoirs. It also provides
guidance to water treatment operators
for evaluating and maintaining water
quality in reservoirs. The document
discusses:
• Existing regulations and policies
pertaining to uncovered reservoirs;
• Development of a reservoir
management plan;
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19097
• Potential sources of water quality
degradation and contamination;
• Operation and maintenance of
reservoirs to maintain water quality; and
• Mitigating potential water quality
degradation.
As discussed in the 1997 IESWTR
NODA (EPA, 1997b), 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. Potential sources
of contamination to uncovered
reservoirs and tanks include airborne
chemicals, surface water runoff, animal
carcasses, animal or bird droppings and
growth of algae and other aquatic
organisms due to sunlight that results in
biomass (Bailey and Lippy, 1978). In
addition, uncovered reservoirs may be
subject to contamination by persons
tossing items into the reservoir or illegal
swimming (Pluntze 1974; Erb, 1989).
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, Silverman et
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.,
1996a; Geldreich, 1990; Payer and
Ungar, 1986;). 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). 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).
In addition, algae can cause drinking
water taste and odor problems as well
as impact water treatment processes. A
1997 study conducted by the City of
Seattle (Seattle Public Utilities, 1997)
evaluated nutrient loadings by three
groups of birds at Seattle's open
reservoirs. Table IV.9 indicated the
amount of soluble nutrient loadings
estimated over the course of the year. It
shows that bird feces may contribute
nutrient loadings that can enhance algal
growth in the reservoir.
TABLE IV.9.—1997 NUTRIENT LOADINGS BY BIRD GROUPS IN SEATTLE'S OPEN RESERVOIRS
Resea-oir
Beacon Hill*
Bitter Lake
Green Lake
Lake Forest ,
Lincoln ,
Maple Leaf
Myrtle
Volunteer
West Seattle
Geese
Nitr.
kg/yr
0.00
0.82
1.78
2.23
0.00
2.16
0.00
0.00
0.40
Phos.
kg/yr
0.00
0.24
0.52
0.65
0.00
0.63
0.00
0.00
0.12
Gulls
Nitr.
kg/yr
0.00
0.01
0.03
0.36
0.24
0.13
0.08
0.01
0.38
Phos.
kg/yr
0.00
0.00
o.o'i
0.11
0.07
0.04
0.02
0.00
0.11
Ducks
Nitr.
kg/yr
0.00
0.06
0.53
0.07
0.01
0.35
,0.01
0.01
0.02
Phos.
kg/yr
0.00
0.02
0.16
0.02
0.00
0.10
0.00
0.00
0.01
Overall
Total
kg/yr
0.00
1.15
3.04
3.43
0.31
3.42
0.12
0.03
1.03
Cone.
(mg/L)
0.00
14.09
16.05'
15.09
3.96
15.43'
4.35
0.42
4;
c. Proposed Requirements
In today's proposed rule EPA is
requiring surface water and GWUDI
systems that serve fewer than 10,000
people to cover all new reservoirs,
holding tanks or other storage facilities
for finished water for which
construction begins 60 days after the
publication of the final rule in the
Federal Register. Today's proposed rule
does not apply these requirements to
existing uncovered finished water
reservoirs.
d. Request for Comments
EPA solicits comments regarding the
requirement to require that all new
reservoirs, holding tanks and storage
facilities for finished water be covered.
D. Recycle Provisions for Public Water
Systems Employing Rapid Granular
Filtration Using Surface Water and
GWUDI as a Source
Section 1412(b)(14) of the 1996
SDWA Amendments requires EPA to
promulgate a regulation to govern the
recycle of filter backwash within the
treatment process of public water
systems. "The Agency is concerned that
the recycle of spent filter backwash and
other recycle streams may introduce
additional Cryptosporidium oocysts to '
the treatment process. Adding oocysts to
the treatment process may increase the
risk oocysts will occur in finished water
supplies and threaten public health. The
Agency is further concerned because
Cryptosporidium is not inactivated by
standard disinfection practice, an
important treatment barrier employed to
control microbial pathogens. Oocysts
returned to the plant by recycle flow ,
therefore remain a threat to pass through
filters into the finished water.
The Agency engaged in three primary
information gathering activities to
investigate the potential risk posed by
returning recycle flows that may contain
Cryptosporidium to the treatment
process. First, die Agency performed a
broad literature search to gather
research papers and information on the
occurrence of Cryptosporidium and
organic and inorganic materials in
recycle flows. The literature search also
sought information regarding the
potential impact recycle may have on
plant treatment efficiency. Second, the
Agency worked with AWWA,
AWWSCo., and Cincinnati Water Works
to develop twelve issue papers on
commonly generated recycle flows
(Environmental Engineering and
Technology, Inc.,1999). These papers
are summarized in the next section.
Information from EPA's literature search
was incorporated into the issue papers.
Third, the Agency presented
preliminary data and potential
regulatory components to stakeholders,
and solicited feedback, at public
meetings in Denver, Colorado, and
Dallas, Texas. EPA also received
valuable input from representatives of
small water systems through the
SBREFA process.
Through the above activities, the
Agency has identified four primary
concerns regarding the recycle of spent
filter backwash and other recycle
streams within the treatment process of
PWSs. The first concern is that some
recycle flows contain Cryptosporidium
oocysts, frequently at higher
concentrations than plant source waters.
Recycling these flows may increase the
number of oocysts entering the plant
and the number of oocysts reaching the
filters. Loading more oocysts to the :
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filters could increase finished water
oocyst concentrations. The second
concern regards the location in the
treatment process recycle flow is
returned. The return of recycle at the
point of primary coagulant addition or
downstream of it may disrupt treatment
chemistry by introducing residual
coagulant or other treatment chemicals
to the process stream and thereby lower
plant treatment efficiency. Also, recycle
flow returned to the clarification
process may not achieve sufficient
residence time for oocysts in the recycle
flow to be removed, or it may create
hydraulic currents that lower the unit's
overall oocyst removal efficiency. The
third concern regards direct filtration
plants. Direct filtration plants do not
employ clarification in their primary
treatment process to remove suspended
solids and oocysts; all oocyst removal is
achieved by the filters. If the recycle
flow is not treated before being returned
to the plant, all of the oocysts captured
by a filter during a filter run will be
returned to the plant and again loaded
to the filters. This may lead to ever
increasing levels of oocysts being
applied to the filters and could increase
the concentration of oocysts in finished
water. Therefore, it is important for
direct filtration plants to provide
adequate recycle flow treatment to
remove oocysts and protect the integrity
of the filters and finished water quality.
Finally, the fourth concern is that the
direct recycle of spent filter backwash
without first providing treatment,
equalization, or some form of hydraulic
detention for the recycle flow, may
cause plants to exceed State-approved
operating capacity during recycle
events. This can cause clarification and
filter loading rates to be exceeded,
which may lower overall oocyst removal
provided by the plant and increase
finished water oocyst concentrations.
EPA has particular concerns regarding
the direct recycle of spent filter
backwash water as it is produced (i.e.,
recycle flow is not retained in an
equalization basin, treatment unit, or
oilier hydraulic detention unit prior to
reintroduction to the main treatment
process) for the following reasons:
(1) Direct recycle may cause operating
rates for clarification and filtration to be
exceeded, which may lower overall
Cryptosporidium removal;
(2) Direct recycle may hydraulically
upset some plants, lowering overall
plant treatment performance, and;
(3) Clarification and filtration
operating rates may be exceeded at
precisely the time recycle flow may be
returning large numbers of oocysts to
the treatment process.
The impact of direct recycle practice
to smaller plants with few filters is of
greatest concern because return of
recycle flow can double or triple plant
influent flow, which may hydraulically
overload the plant and reduce oocyst
removal.
Since standard disinfection practice
does not inactivate Cryptosporidium, its
control is entirely dependent on
physical removal processes. The Agency
is concerned that direct recycle may
cause some plants to exceed operating
capacity and thus lower their physical
removal capabilities. This can increase
the risk of oocysts entering the finished
water and lead to an increased risk to
public health.
The limited data (Cornwell and Lee,
1993) EPA has identified regarding
plants with existing equalization and/or
treatment indicates they may be at no
greater risk of hydraulic upset or
degradation of oocyst removal
performance than non-recycle plants.
Given current data limitations, it is
reasonable to assume the presence and
utilization of adequate recycle flow
equalization and/or treatment processes
will alleviate the potential for hydraulic
disruptions and the impairment of
treatment performance. Data suggesting
otherwise is currently unavailable.
The potential for recycle to return
significant numbers of oocysts to the
treatment train does provide a general
basis for concern regarding the impact
of recycle practice to finished water
quality. However, the Agency does not
currently believe data warrants a
national regulation requiring all recycle
plants to provide recycle flow
equalization or treatment for the
following reasons:
(1) Data correlating oocyst occurrence
in recycle streams to increased oocyst
occurrence in finished water is
unavailable;
(2) Data regarding the response of full-
scale plants to recycle events is limited;
(3) Data is not available to determine
the level of recycle flow equalization or
treatment full-scale systems may need,
if any, to control the risk of oocysts
entering finished water, and;
(4) Whether and the extent to which
oocyst occurrence in source water
influences the necessary level of recycle
treatment and equalization is unknown.
The Agency believes requiring plants
that may be at greater risk due to
recycle, such as direct recycle plants
and direct filtration plants, to
characterize their recycle practice and
provide data to the State for its review
provides a cost effective opportunity to
increase public health protection and
supply a measure of safety to finished
drinking water supplies. EPA believes
that today's proposal will address
potentially higher risk recycle situations
that may threaten the performance of
some systems, and will do so by
allowing State drinking water programs
to consider site-specific treatment
conditions and needs. The Agency
believes these recycle provisions are
needed to protect plant performance,
the quality of finished water supplies,
and to provide an additional measure of
public health protection.
1. Treatment Processes That Commonly
Recycle and Recycle Flow Occurrence
Data
a. Treatment Processes That Commonly
Recycle
The purpose of this section is to
provide general background on common
treatment plant processes, fundamental
plant operations, and the origin of plant
recycle streams. Detailed information on
the specific recycle flows these
processes generate are presented after
this background discussion. Four
general types of water treatment
processes, conventional filtration, direct
filtration, softening, and contact
clarification, are discussed. Although
there are numerous variations of these
four treatment processes, only the most
basic configurations are discussed here.
The operation of package plants and
options to returning recycle to the
treatment process are also summarized.
i. Conventional Treatment Plants
Conventional water filtration plants
are defined by the use of four essential
unit processes: Rapid mix, coagulation/
flocculation, sedimentation, and
filtration. Sedimentation employs
gravity settling to remove floe and
particles. Particles not removed by
sedimentation may be removed by the
filters. Periodically, accumulated solids
must be removed from the
sedimentation unit. These solids,
termed "residuals," are currently
disposed to sanitary sewer, treated with
gravity thickening, or some other
process prior to returning them to plant
headworks or other locations in the
treatment train. Clarification processes
other than sedimentation may also be
used, and they also produce process
residuals.
Clarification sludge may be processed
on-site if the plant is equipped with
solids treatment facilities. Commonly
employed treatment processes include
thickeners, dewatering equipment (e.g.,
plate and frame presses, belt filter
presses, or centrifuges), and lagoons.
Each of these processes produces
residual water streams that are currently
returned to the treatment process at the
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19099
headworks or other locations prior to
filtration. The volume of residuals
produced by clarification depends upon
the amount of solids present in the raw
water, the dose and type of coagulant
applied, and the concentration of solids
in the treated water stream.
The one residual stream associated
with filtration, spent filter backwash
water, is produced during periodic
backwashing events performed to
remove accumulated solids from the
filter. Spent filter backwash is
frequently returned to the treatment
process at the head of the plant, other
locations prior to the filters, or disposed
of to sanitary sewer or surface water.
Some plants have the capability to send
the filtrate produced during the filter
ripening period to plant headworks, a
raw water reservoir, or to a sanitary
sewer or surface water rather than to the
clear well as finished water. This
practice, referred to as "filter-to-waste"
is used to prevent solids, which pass
through the filter more easily during the
ripening period, from entering the
finished water.
Filter backwash operations can differ
significantly from plant to plant. The
main variables are the time between
backwashes (length of filter run), the
rate of backwash flow, the duration of
the backwash cycle, and the
backwashing method. The time between
filter backwashes is generally a function
of either run time, headless, or solids
breakthrough. Both headloss and solids
breakthrough can be dependent upon
the quality of the sedimentation
effluent. Regardless of the variable
driving backwash frequency, the
interval between backwashes typically
vary from 24 to 72 hours. Recommended
backwash frequency is every 24-48
hours (ASCE/AWWA, 1998).
There are a number of different
methods that can be used to backwash
a filter. These include: Upflow water
only, upflow water with surface wash,
and air/water backwash. Air/water
backwash systems typically use 30-50
percent less water than the other two
methods. The filter backwash flow rate
can vary, depending on media type,
water temperature, and backwash
method, but generally has a maximum
of 15-23 gpm/ftz (air/water backwash
may have a lower maximum rate of 6-
7 gpm/ft2). A number of different
backwash sequences are employed, but
a typical backwash consists of a low rate
wash (6-7 gpm/ft2 for several minutes),
followed by a high rate wash (15-23
gpm/ft2 for 5-15 minutes), which is
then followed by a final low rate wash
(6-7 gpm/ft2 for several additional
minutes). Some treatment plants only
use a high rate wash for 15 to 30
minutes. Backwash rates are
significantly higher than filtration rates,
which vary from 1 to 8 gpm/ft2.
ii. Direct Filtration Plants
The direct filtration process is similar
to conventional treatment, except the
clarification process is not present.
Direct filtration plants produce the same
filter residual as conventional filtration
plants, namely filter backwash, and may
also generate a filter-to-waste flow.
Direct filtration plants do not produce
clarification residuals because
clarification is not employed. Filter
backwash may be either recycled to the,
head of the plant or discharged to
surface waters or a sanitary sewer.
Although direct filtration plants
generally treat source waters that have •
low concentrations of suspended
material, the solids loading to the filters
may be higher than at conventional
plants because solids are not removed in
a clarification process prior to filtration.
If spent filter backwash is not treated to
remove solids prior to recycle, solids
loading onto the filters will continue to
increase over time, as an exit from the
treatment process is unavailable. Filter
run length may be shorter in some direct
filtration plants relative to conventional
plants because the solids loading to the
filters may be higher due to the lack of
a clarification process. The
concentration of solids in the source ,
water is a key variable in filter run
length.
iii. Softening Plants
Softening plants utilize the same basic
treatment processes as conventional
treatment plants. Softening plants
remove hardness (calcium and
magnesium ions) through precipitation,
followed by solids removal. Many
softening plants employ a two-stage
process, which consists of a rapid mix-
flocculation-sedimentation sequence, in
series, followed by filtration. Others use
a single stage process, resembling
conventional treatment plants.
Precipitation of the calcium and
magnesium ions is accomplished
through the addition of lime (calcium
hydroxide), with or without soda ash
(sodium carbonate), which reacts with
the calcium and magnesium ions in the
raw water to form calcium carbonate
and magnesium hydroxide. The
precipitation of the calcium carbonate
can be improved by recirculating some
of the calcium carbonate sludge into the
rapid mix unit because the additional
solids provide nucleation points for the
precipitation of calcium and
magnesium. Without this recirculation,
additional hydraulic detention time in;
the flocculation and sedimentation
basins may be required to prevent
excessive scale deposits in the plant
clearwell or in the distribution system.
A softening plant generally has the
same residual streams as a conventional
plant: Filter backwash, sedimentation
solids, and thickener supernatant and
dewatering liquids. A filter-to-waste
flow may also be generated. These
residual streams are either disposed or
recycled within the plant. A portion of
the sedimentation basin solids are
commonly recycled as the
sedimentation basin solids contain
significant quantities of precipitated
calcium carbonate, recycle of these
solids reduces the required chemical
dose. Solids are generally recycled into
the rapid mix chamber to maximize
their effectiveness.
iv. Contact Clarification Plants
In the contact clarification process,
the flocculation and clarification (and
often the rapid mix) processes are
combined in one unit, an upflow solids
contactor or contact clarifier. Contact
clarifiers are employed in both softening
and non-softening processes. Raw water
flows into the contact clarifier at the top
of the central compartment, where
chemical addition and rapid mix occurs.
The water then flows underneath a skirt
and into the outer sedimentation zone
where solid separation occurs. A large
portion of previously settled solids from
the sedimentation zone is circulated to
the mixing zone to enhance
flocculation. The remainder of the
solids are disposed to prevent their
accumulation. Circulation and disposal
of accumulated solids allows clarifier
loading rates to be 10 to 20 times greater
than loading rates for conventional
sedimentation basins. Solids
recirculation rates are generally
different for softening and turbidity
removal applications, with rates of up to
12 times the raw water flow for
softening processes and up to 8 times
the raw water flow for non-softening
processes (ASCE/AWWA, 1998).
Following clarification, treated water
from the contactor is then filtered.
The residual streams from contact
clarification plants are similar to those
for conventional filtration plants. They
include filter backwash, clarification
solids, thickener supernatant, and
dewatering liquids. The key operational
consideration for these types of systems
is the maintenance of a high
concentration of solids within the skirt
to allow high loading rates while
maintaining adequate solids removal.
Solids recirculation (e.g., recycle) helps
contact clarification processes maintain
the necessary solids concentration.
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Softening plants may also generate filter
to waste flow.
v. Package Plants
Package plants are typically used to
produce between a few thousand to 1
million gallons of water per day.
Package plants can employ a
conventional treatment train, as well as
proprietary unit processes. Package
plants typically include the same
processes found in large plants,
including coagulation, flocculation,
clarification and filtration. The potential
recycle streams are also comparable.
The recycle of filter backwash may
occur, however, the typical package
plant may not be designed to convey
process streams back into the plant as
recycle.
vi. Summary of Recycle Disposal
Options
Two recycle disposal options
available to some plants are direct
discharge to sanitary sewers or
discharge to surface waters. Discharge of
recycle waters to the municipal sewer
system may occur when the treatment
plant and Publicly Owned Treatment
Works (POTW) are under the same
authority or when the plant has access
to a sanitary sewer and a POTW agrees
to accept its discharge.
There may be a fee associated with
discharge to a sanitary sewer system,
and the total fee may vary with the
volume of backwash effluent discharged
as well as the amount of solids in the
effluent (Cornwell and Lee, 1994). In
addition to the fee requirement,
discharging into the sewer system may
require the plant to equalize the effluent
prior to discharging to the POTW. The
equalization process requires holding
the effluent in tanks and gradually
releasing it into the sanitary sewer
system. The fee associated with sanitary
sewer discharge may influence whether
a plant recycles to the treatment process
or discharges to a sanitary sewer.
Another option to recycle within the
treatment process is the direct discharge
of recycle flow to surface waters, such
as creeks, streams, rivers, and reservoirs.
Direct discharge is a relatively common
method of disposal for water treatment
plant flows. A National Pollutant
Discharge Elimination System (NPDES)
permit requires that certain water
quality conditions be met prior to the
discharge of effluent into surface waters.
Treatment of the effluent prior to
discharge may be required. The cost of
effluent treatment may influence
whether plants recycle within the
treatment process or discharge to
surface water.
b. Recycle Flow Occurrence Data
EPA has not regulated recycle flows
in previous rulemakings. The 1996
SDWA Amendments have lead the
Agency to perform an examination of
recycle flow occurrence data for the first
time. EPA discovered through its
literature search and its work with
AWWA, AWWSCo., and Cincinnati
Water Works to develop the issue
papers, that the amount of recycle
stream occurrence data available is very
limited, particularly for
Cryptosporidium, the primary focus of
this regulation. This may be because
Cryptosporidium was identified as a
contaminant of concern relatively
recently and because currently available
oocyst detection methods have
limitations.
Twelve issue papers were developed
to compile information on several
commonly produced recycle streams.
Each individual paper summarizes how
the recycle stream is generated, the
typical volume generated, characterizes
the occurrence of various recycle stream
constituents to the extent data allows,
(i.e., occurrence of Cryptosporidium and
inorganic and organic material), and
briefly discusses potential impacts of
recycling the stream. The discussion of
potential impacts is usually brief, due to
overall data limitations and particularly
due to a lack of data on
Cryptosporidium occurrence. The 12
recycle streams examined include:
• untreated spent filter backwash
water
• gravity settled spent filter backwash
water
• combined gravity thickener
supernatant (spent filter backwash and
clarification process solids)
• gravity thickener supernatant from
sedimentation basin solids
• mechanical dewatering device
concentrate
• untreated basin solids
• lagoon decant
• sludge drying bed leachate
• monofill leachate membrane
concentrate
• ion exchange regenerate
• minor streams
A total of 112 references were used to
complete the issue papers, and
AWWSCo. and Cincinnati Water Works
performed sampling of non-microbial
recycle stream constituents to
supplement occurrence information.
Cryptosporidium occurrence data was
only identified for five recycle streams,
namely: untreated spent filter backwash
water, gravity settled spent filter
backwash water, untreated
sedimentation basin solids, combined
thickener supernatant, and sludge
drying bed leachate. Oocysts may occur
in the other recycle streams as well, but
published occurrence data was not
identified. The issue papers and
supporting literature indicate data does
not exist to correlate oocyst occurrence
in recycle streams to the occurrence of
oocysts in finished water. However, the
issue papers did identify data showing
that oocysts occur in recycle streams,
often at concentrations higher than that
of the source water.
Cryptosporidium is not the only
constituent of recycle waters. Other
common constituents are manganese,
iron, aluminum, disinfection
byproducts, organic carbon, Giardia
lamblia and particles. EPA does not
currently have data to indicate these
constituents occur in recycle streams at
levels which threaten treatment plant
performance, finished water quality, or
public health. Additionally, current
regulations may largely control any
minor risk these constituents may
present. For example, organic matter in
recycle flow may form disinfection
byproducts in the presence of oxidants.
The Stage 1 DBPR, which requires
monitoring for disinfection byproducts,
will identify systems experiencing
disinfection byproduct occurrence
above or near applicable MCLs through
distribution system monitoring.
Additionally, Secondary Maximum
Contaminant Levels (SMCLs) have been
promulgated to control occurrence of
aluminum, iron, and manganese at
levels of .05-.2 mg/1, .3 mg/1, and .05
mg/1, respectively. Particle levels are
controlled by effluent turbidity
standards and Giardia lamblia is
controlled through a combination of
disinfection and filtration requirements.
EPA believes existing regulations
control these recycle stream
constituents. Therefore, their control is
not a primary goal of today's proposal.
Additionally, detailed discussion of
these constituents is not provided in the
below summary of the issue papers
because: (1) control of Cryptosporidium
is the focus of the recycle provisions,
and; (2) concentrations of inorganic and
organic materials reported in lie issue
papers are for recycle streams, not
finished water occurrence. The recycle
stream concentrations will be
significantly diluted by mixing with
source water.
The occurrence of recycle flow
constituents other than
Cryptosporidium is not discussed in
today's preamble for the above reasons.
The following discussion of recycle
stream occurrence data covers only
untreated spent filter backwash water,
gravity settled spent filter backwash
water, combined gravity thickener
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19101
supernatant (a combination of spent
filter backwash and clarification process
solids), gravity thickener supernatant
from clarification process solids, and
mechanical dewatering device liquids.
These five recycle streams are discussed
in detail because they are most likely to
present a threat to treatment plant
performance or finished water quality
when recycled. For example, treated
and untreated spent filter backwash
water and thickener supernatant are the
only two recycle streams of sufficient
volume to cause plants to exceed their
operating capacity during recycle
events. The five recycle streams
discussed below are also most likely to
contain Cryptosporidium.
Copies of all the issue papers are
available for public review in the Office
of Water docket for this rulemaking.
Portions of the following recycle stream
descriptions use excerpts from the issue
papers.
/. Untreated Spent Filter Backwash
Water
Water treatment plants that employ
rapid granular filtration (e.g.,
conventional, softening, direct filtration,
contact clarification) generate spent
filter backwash water. The backwash
water is generated when water is forced
through the filter, counter-current to the
flow direction during treatment
operations, to dislodge and remove
accumulated particles and pathogens
residing in the filter media. Backwash
rates are typically five to eight times the
process rate, and are used to clean the
filter at the end of a filter run, which is
generally 24 to 72 hours in length.
Backwash operations usually last from
10 to 25 minutes. The flow rate and
duration of backwashing are the primary
factors that determine the volume of
backwash water produced. Once the
backwashing process is complete, the
backwash water and entrained solids are
either disposed of to a sanitary sewer,
discharged to a surface water, or
returned to the treatment process. Plants
currently return spent filter backwash to
the treatment process at a variety of
locations, usually between plant
headworks and clarification. Data
regarding common recycle return
locations is discussed in the next
section of this preamble.
Spent filter backwash can be returned
to the treatment process directly as it is
produced, be detained in an
equalization basin, or passed through a
treatment process, such as clarification,
prior to being returned to the plant. On
a daily basis, spent filter backwash can
range from 2 to 10 percent of plant
production. Spent filter backwash is
usually produced on an intermittent
basis, but large plants with numerous
filters may produce it continuously. At
small and mid-size plants, large volume,
short duration flows of spent filter
backwash are usually produced. This
may cause some plants, particularly
smaller plants that recycle directly
without flow equalization or treatment,
to exceed their operating capacity or to
experience hydraulic disruptions, both
of which may negatively impact
treatment efficiency and oocyst removal.
The concentrations of :
Cryptosporidium reported in the
untreated spent filter backwash issue
paper ranges from non-detect to a
concentration of 18,421 oocysts per 100
L. This range is not amenable to formal
statistical analysis, but rather provides a
summary of minimum and maximum
oocyst concentrations reported in
available literature. Although a few
studies report isolated data points of
freater than 10,000 oocysts/lOOL for
Iter backwash water (Rose et al., 1989;
Cornwell and Lee, 1993; Colbourne,
1989), occurrence studies that collected
the largest number of samples reported
mean filter backwash oocyst occurrence
concentrations of a few hundred oocysts
per 100L (States et al., 1997; Karanis et
al., 1996). The high concentration of
oocysts found in some spent filter
backwash samples is cause for concern,
because oocysts are not inactivated by
standard disinfection practice. They
remain a threat to pass through the plant
into the finished water if they are
returned to the treatment process.
However, current oocyst detection
methods do not allow the occurrence of
oocysts in spent filter backwash water to
be correlated to finished water oocyst
concentrations for a range of plant
types, source water qualities, and
recycle practices. Today's proposal does
not require the installation of recycle
equalization or treatment for spent filter
backwash water on a national basis due
to these data limitations.
The Agency is concerned that certain
recycle practices, such as returning
spent filter backwash to locations other
than prior to the point of primary
coagulant addition, or hydraulically
overloading the plant with recycle flow
so it exceeds its State approved
operating capacity, may present risk to
finished water quality and public :
health. Exceeding plant operating
capacity during recycle events may
cause greater risk to finished water
quality, because plant performance is
potentially being lowered at precisely
the time oocysts are returned to the ;
plant in the recycle flow. To address
this concern, today's proposal requires
that certain direct recycle plants that
recycle spent filter backwash water and/
or thickener supernatant to perform a
self assessment of their recycle practice
and report the results to the State. The
self assessment requirements are
discussed in detail later in this
preamble.
ii. Gravity Settled Spent Filter Backwash
Water
Gravity settled spent filter backwash
water is generated by the same filter
backwash process and is produced in
the same volume as untreated spent
filter backwash water. The difference
between the two streams is that the
former is treated by gravity settling prior
to its return to the primary treatment
process. Sedimentation treatment is
usually accomplished by retaining the
spent filter backwash water in a
treatment unit for a period of time to
allow suspended solids (including
oocysts) to settle to the bottom of the
basin. Polymer may be used to improve
process efficiency. The water that leaves
the basin is gravity settled spent filter
backwash water. Removing solids from
the spent filter backwash causes only a
minor reduction in volume as the solids
content of the untreated stream is low,
usually below 1 percent.
Providing gravity settling for spent
filter backwash is advantageous for two
reasons. First, the sedimentation process
detains the spent filter backwash in
treatment basins for a period of hours,
which lowers the possibility a large
recycle volume will be returned to the
plant in a short amount of time and
cause the plant operating capacity to be
exceeded. Second, treating the spent
filter backwash flow can remove
Cryptosporidium oocysts from the flow,
which will reduce the number of
oocysts returned to the plant.
Limited data show that sedimentation
can effectively remove oocysts.
Cornwell and Lee (1993) conducted
limited sampling of spent filter
backwash water at two plants prior to
and after sedimentation treatment. The
first facility-practiced direct filtration
and was sampled twice. The
Cryptosporidium concentrations into
and out of the sedimentation basin
treating spent filter backwash were 900/
100L and 140/100L, respectively, for the
first sampling and 850/100L in the
influent and 750/100L in the effluent for
the second sampling. At the second
plant a sludge settling pond received
both sedimentation basin sludge and
spent filter backwash, and the spent
filter backwash oocyst concentration
was 16,500/lOOL, and the treated
recycle water concentration was 420/
100L. In a study by Karanis (1996),
Cryptosporidium was regularly detected
in settled backwash waters. Of the 50
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samples collected, 82 percent tested
positive for Cryptosporidium. The mean
value for Cryptosporidium was 22
oocysts/lOOL.
Sedimentation treatment can remove
oocysts from spent filter backwash, but
data indicate oocysts remain in gravity
settled spent filter backwash water even
after treatment. The Agency believes
that sedimentation treatment for spent
filter backwash waters is capable of
removing oocysts and improving the
quality of the water prior to recycle.
However, given current data limitations,
the Agency does not believe it is
possible to specify, in a national
regulation, the conditions (e.g., source
water oocyst concentrations, primary
treatment train performance,
concentration of oocysts in spent filter
backwash, ability of sedimentation to
remove oocysts under a range of
conditions) under which sedimentation
treatment of spent filter backwash water
may be appropriate. This decision is
best made by State programs to allow
consideration of site-specific conditions
and treatment needs.
Hi. Combined Gravity Thickener
Supernatant
Combined gravity thickener
supernatant is derived from the
treatment of filter backwash water and
sedimentation basin solids in gravity
thickener units. These two flows may
not reside in the thickener at the same
time or in equal volumes, depending on
plaint operations. The volume of
thickener supernatant generated at a
water treatment plant is a function of
the type of flows it treats,- the solids
content of the influent stream, and the
method of thickener operation.
Regardless of whether a continuous or a
batch process is used, a number of
factors, including residuals production
(a function of plant production, raw
water suspended solids, and coagulant
dose), volume of spent filter backwash
water produced, and the level of
treatment provided to thickener influent
streams, directly affect the quantity of
thickener supernatant produced.
The flow entering the thickener is
primarily spent filter backwash water.
Sedimentation basin solids is the
second largest flow. Flow from
dewatering devices, which is generated
by the dewatering of residuals, may
comprise a minor volume entering the
thickener. Combined thickeners will
have an influent that may be eighty-
percent spent filter backwash or more
by volume. About eighty-percent of the
solids entering the thickener will be
from the sedimentation basin sludge, as
spent filter backwash water has a
comparatively low solids concentration.
A recent FAX survey (AWWA, 1998)
identified more than 300 water
treatment plants in the United States
with production capacities ranging from
less than 2 mgd to greater than 50 mgd
that recycle spent filter backwash water.
Many of the survey respondents
indicated that they recycle more than
just spent filter backwash water. Based
on the survey and published literature,
thickener supernatant is probably the
second largest and second most
frequently recycled stream at water
treatment facilities after spent filter
backwash.
Data summarized in the issue paper
showed that thickener supernatant
quality varies widely, due in large part
because the type and quality of recycle
streams entering thickeners varies over
time and from plant to plant. The
turbidity, total suspended solids, and
particle counts of thickener effluent are
directly impacted by the quality of
water loaded onto the thickener,
thickener design, and thickener
operation (e.g., residence time, use of
polymer).
Data on the occurrence of
Cryptosporidium was limited to two
samples, with oocyst occurrence ranging
from 82 to 420 oocysts per 100 L. Data
is too limited, and practice varies too
widely, to draw conclusions on the
impact recycle of this flow may have on
plant performance. However, given that
the contents of the thickener have been
treated and the amount of flow
produced by gravity thickeners is
relatively modest, it may be feasible to
recycle the flow in a manner that
minimizes adverse impact.
Additionally, treatment plant personnel
have a vested interest in optimizing
thickener operation to minimize sludge
dewatering and handling costs;
optimization of thickener operation is
likely to assist oocyst removal.
However, additional data is needed to
characterize the occurrence of
Cryptosporidium and the potential
impact recycle of combined thickener
supernatant may have on finished water
quality.
iv. Gravity Thickener Supernatant from
Sedimentation Solids
Gravity settled sedimentation basin
solids are sedimentation basin solids
that have undergone settling to allow
solid sludge components to settle to the
bottom of a gravity thickener. The
supernatant from the thickener is a
potential recycle flow. The tank bottom
is sloped to enhance solids thickening
and collection and removal of settled
solids is accomplished with a bottom
scraper mechanism. If the supernatant is
recycled, it can be returned to the plant
continuously or intermittently,
depending on whether the thickener is
operated in batch mode. Thickeners
may receive and treat both spent filter
backwash water and sedimentation
basin solids. For purposes of this
discussion, and the data presented in
the issue paper, the gravity thickener is
only receiving sedimentation basin
solids.
The volume of treated sedimentation
basin solids supernatant generated is
dependent on the amount of sludge
produced in the sedimentation basin,
the solids content of the sludge, and
method of thickener operation. Sludge
production is a function of plant
production, raw water suspended
solids, coagulant type, and coagulant
dose. The quantity of sedimentation
basin sludge supernatant is
approximately 75 to 90 percent of the
original volume of sedimentation basin
sludge produced.
There is a very limited amount of data
on the quality of thickener supernatant
produced by gravity settling of only
sedimentation basin solids (i.e., spent
filter backwash and other flows are not
added to the thickener), and no data was
identified regarding the concentration of
Cryptosporidium that occur in the
supernatant. As is the case with
combined gravity thickener supernatant,
it is difficult to determine what impact,
if any, the return of the supernatant may
have on plant operations and finished
water quality due to limited data.
Additional data is necessary to
determine the concentration of oocysts
in this recycle stream, and to
characterize the impact its recycle may
have to plant performance.
v. Mechanical Dewatering Device
Liquids
Water treatment plant residuals
(usually thickened sludge) are usually
dewatered prior to disposal to remove
water and reduce volume. Two common
mechanical dewatering devices used to
separate solids from water are the belt
filter press, which compresses the
residuals between two continuous
porous belts stretched over a series of
rollers, and the centrifuge, which
applies a strong centrifugal force to
separate solids from water. The plate
and frame press is another dewatering
device that contains a series of filter
plates, supported and contained in a
structured frame, which separate sludge
solids from water using a positive
pressure differential as the driving force.
Water removed from the solids with a
belt filter press is called filtrate, from a
filter press it is called pressate, and the
water separated from the residuals with
a centrifuge is referred to as centrate.
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19103
These streams will be collectively
referred to as "dewatering liquid" for
the following discussion.
The volume of dewatering liquid
produced depends primarily on the
volume and solids content of the
thickened residuals fed to the
mechanical dewatering device. Plants
that produce small sludge volumes, and
hence a low volume of thickener
residuals, will process fewer residuals
in the mechanical dewatering device
and hence produce a smaller volume of
dewatering liquid than a plant
producing a large volume of solids, all
else being equal. Since residuals are
often thickened (typically to about 2 •<,
percent solids) prior to dewatering, the
volume of the dewatering device feed
stream is significantly lower than the
volume of sedimentation basin residuals
generated. If the sedimentation basin
sludge flow is assumed to be 0.6 percent
of plant production, then dewatering
device flow may be approximately 0.1 to
0.2 percent of plant flow. Generally
these streams are mixed in with other
recycle streams prior to being returned
to the plant. Mechanical dewatering
devices may be operated intermittently,
after a suitable volume of residuals have
been produced for dewatering. The
production of dewatering liquid and its
recycle may not be a continuous
process.
Data on the constituents in
dewatering liquid were found in three
references, one on belt filter press
liquids, one on plate and frame pressate,
and one on centrifuge centrate. Data on
the occurrence of Cryptosporidium was
not identified. Given the small,
intermittent flow produced by
mechanical dewatering devices, recycle
flows from them are unlikely to cause
plants to exceed operating capacity.
However, it is possible that dewatering
device liquid contains Cryptosporidium
because it derived from solids likely to
hold a large numbers of oocysts.
Additional data is necessary to
determine the concentration of oocysts
in this recycle stream, and to
characterize any impact its recycle may
have to plant performance.
2. National Recycle Practices
a. Information Collection Rule
Public water systems affected by the
ICR were required to report whether
recycle is practiced and sample
washwater (i.e., recycle flow) between
the washwater treatment plant (if one
existed) and the point at which recycle
is added to the process train. Sampling
of plant recycle flow was required prior
to blending with the process train.
Monthly samples were required for pH,
alkalinity, turbidity, temperature,
calcium and total hardness, TOG, UV254,
bromide, ammonia, and disinfectant
residual if disinfectant was used.
Systems were also required to measure
recycle flow at the time of sampling, the
twenty four hour average flow prior to
sampling, and report whether treatment
of the recycle was provided and, if so,
the type of treatment. Reportable
treatment types were plain
sedimentation, coagulation and
sedimentation, filtration, disinfection,
or a description of an alternative
treatment type. Plants were also
required to submit a plant schematic to
identify sampling locations. EPA used
the sampling schematics and other
reported information to compile a
database of national recycle, practice.
i. Recycle Practice
The Agency developed a database
from the ICR sampling schematics and
other reported information. Table IV.10
summarizes the plants in the database.
Of the 502 plants in the database at the
time the analysis was performed, 362
used rapid granular filtration.
TABLE IV. 10.—RECYCLE PRACTICE AT
ICR PLANTS
Plant classification
All ICR plants
Filtration plants a
Filtration plants recycling b
Filtration plants treating recycle
Recycle plants serving 5100,000
Recycle plants serving <1 00,000
Num-
ber
502
362
226
148
168
58
"Defined as conventional, lime softening,
other softening, and direct filtration plants.
b Plants report existence of a recycle
stream, not its origin.
These plants are classified as
conventional, lime softening, other
softening, and direct filtration. The
remaining 140 plants in the database do
not employ rapid granular filtration
capability and generally provide
disinfection for ground water. Of the
362 filtration plants in the database, 226
(62.4 percent) reported recycling to the
treatment process. Seventy-four percent
of the plants that recycle serve
populations greater than 100,000 and 26
percent serve populations below
100,000. Figure IV.9 shows the
distribution of plants by treatment type
and Figure IV. 10 shows the distribution
of plants by population served. Table
IV. 11 shows that 88 percent of ICR
recycle plants use surface water. An
additional one percent use GWUDI and
another one percent use a combination
of ground water and surface water.
Therefore, 90 percent of ICR recycle
plants use a source water that could
contain Cryptosporidium,
BILLING CODE 6560-50-P
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Federal Register/Vol. 65, No. 69/Monday, April 10, 2000/Proposed Rules
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Federal Register/Vol. 65, No. 69/Monday, April 10, 2000/Proposed Rules
TABLE iv.11.—SOURCE WATER USE BY ICR RECYCLE PLANTS
Source water type
Ground water only
Number of
plants
226
199
3
2
22
Percent of
recycle
plants
100
88
1
1
10
Table IV. 12 shows that 65 percent of
ICR recycle plants report providing
treatment for the recycle flow. The
percentage of plants providing treatment
is the same for the subsets of plants
serving greater than and less than
100,000 people. Sedimentation is the
most widely reported treatment method,
as 77 percent of plants providing
treatment employ it. The database does
not provide information on the solids
removal efficiency of the sedimentation
units. All direct filtration plants
practicing recycle reported providing
treatment for the recycle flow.
TABLE IV. 12.—TREATMENT OF RECYCLE AT ICR PLANTS 1
ICR recycling plants
Other treatment
Number of
plants
226
147
114
14
14
5
Percentage of
recycle plants
100
65
77
10
10
3
1 Disinfection not counted as treatment because it does not inactivate Cryptosporidium.
Table IV.13 indicates that 75 percent
of ICR recycle plants return recycle
prior to rapid mix. Fifteen percent
return it prior to sedimentation, and ten
percent of plants return it prior to
filtration. These percentages hold for the
subsets of plants serving greater than
and less than 100,000 people. The data
indicate that introducing recycle prior
to rapid mix may be a common practice.
EPA believes that introducing recycle
flow prior to the point of primary
TABLE IV.13.—RECYCLE RETURN POINT
coagulant addition, is the best recycle
return location because it limits the
possibility residual treatment chemicals
in the recycle flow will disrupt
treatment chemistry.
Point of recycle return
Prior to filtration
Number of
plants
1224
169
34
21
percent of
plants
100
75
15
10
1 Recycle return point could not be determined for two plants.
The data provides the following
conclusions regarding the recycle
practice of ICR plants: (1) The recycle of
spent filter backwash and other process
streams is a common practice; (2) the
great majority of recycle plants in the
database use filtration and surface water
sources; (3) a majority of plants in the
database that recycle provide treatment
for recycle flow, and; (4) a large majority
of plants in the database that recycle
(approximately 3 out of 4) recycle prior
to the point of primary coagulant
addition.
b. Recycle FAX Survey
The AWWA sent a FAX survey
(AWWA, 1998) to its membership in
June 1998 to gather information on
recycle practices. Plants were not
targeted based on source water type, the
type of treatment process employed, or
any other factor. The survey was sent to
the broad membership to increase the
number of responses. Responses
indicating a plant recycled spent filter
backwash or other flows were compiled
to create a database. The resulting
database included 335 plants. The
database does not contain information
from respondents who reported recycle
was not practiced. Data from some of
the FAX survey respondents also
.populates the ICR database. Plants in
the database are well distributed
geographically and represent a broad
range of plant sizes as measured by
capacity. Figure IV. 11 shows plant
distribution by capacity and Figure
IV. 12 by geographic location. The
following discussion of FAX survey data
is divided into two sections. The first
discusses national recycle practice and
the second discusses options for recycle
disposal in lieu of returning recycle to
the treatment process.
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Federal Register/Vol. 65, No. 69/Monday, April 10, 2000/Proposed Rules
19107
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Federal Register/Vol. 65, No. 69/Monday, April 10, 2000/Proposed Rules
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19109
i. Recycle practice
Data summarized in Table IV. 14 show
that 78 percent of plants in the database
rely on a surface water as their source.
The percentage of plants using source
water influenced by a surface water
(which may contain Cryptosporidium)
could be higher because the data do not
report whether wells were pure ground
water or GWUDI.
TABLE IV.14.—SOURCE WATER USED
BY FAX SURVEY PLANTS
Source water type
Surface Water
River
Reservoir
Lake
Other
Well i
Percent
of plants
78
27
28
16
7
22
1 Wells sources not defined as either ground
water or ground water under the direct influ-
ence of surface water.
Table FV.15 shows that a wide variety
of treatment process types are included
in the data, with conventional filtration
(rapid mix, coagulation, sedimentation,
filtration) representing over half of the
plants submitting data. Upflow
clarification is the second most common
treatment process reported. Ten percent
of plants in the database use direct
filtration. Only four percent of plants do
not use rapid granular filtration.
TABLE IV.15.—TREATMENT TRAINS OF
FAX SURVEY PLANTS
Treatment process type
Rapid mix, coagulation, filtration ....
Upflow clarifier
Softening
Direct filtration
Other
Percent
of
plants 1
51
21
14
10
4
196 percent of plant in the database provide
filtration.
Table IV. 16 indicates that a vast
majority of plants recycle prior to the
point of primary coagulant addition.
Only six percent of plants returned
recycle in the sedimentation basin or
just prior to filtration.
TABLE IV.16.—RECYCLE RETURN
POINT OF FAX SURVEY PLANTS
Return point
Prior to point of primary coagulant
addition
Pre-sedimentation (e.g., rapid mix)
Sedimentation basin
Before filtration
Percent
of plants
83
11
, 4
2
Table IV.17 shows that the majority of
plants in the database provide some
type of treatment for the recycle flow
prior to its reintroduction to the
treatment process. Approximately 70
percent of plants reported providing
treatment, with sedimentation being
employed by over half of these plants.
Equalization, defined as a treatment
technology by the survey, is practiced
by 20 percent of plants in the database.
Fourteen percent of plants reported
using both sedimentation and
equalization.
TABLE IV.17.—RECYCLE TREATMENT
AT FAX SURVEY PLANTS
Treatment type
No treatment
Treatment
Sedimentation
Equalization
Sedimentation and equalization
Lagoon
Others
Percent
of plants
30
70
54
20
14
5
- 7
Table IV.18 summarizes recycle
treatment practice and frequency of
direct recycle based on population
served. The table illustrates that, for
plants supplying data, treatment of
recycle with sedimentation is provided
more frequently as plant service
population deceases. Plants serving
populations of less than 10,000 recycle
directly (27.5 percent) less frequently
than plants serving populations greater
than 100,000 (50 percent). The data
indicate that a majority of small plants
in the database may have installed
equalization or sedimentation treatment
to protect treatment process integrity
from recycle induced hydraulic
disruption. All direct filtration plants in
the FAX survey provide recycle
treatment or equalization.
TABLE IV.18.—RECYCLE PRACTICE BASED ON POPULATION SERVED 1
<10,000
10000-50000
50,000-100000
100.000
#Plants
43
79
35
65
Equalization
9% (n=4)
10% (n=8)
17% (n=6)
35% m=23)
Sedimentation
67% (n=29)
57% (n=45)
54% (n=19)
23% (n=15)
•
Direct recycle
23% (n=10)
33% (n=26)
29% (n=10)
42% (n=27)
Recycle practice
1 Based on 222 surface water plants suppling all necessary data to make determination.
FAX survey data support the
following conclusions regarding the
recycle practice of plants supplying
data: (1) The recycle of spent filter
backwash and other process streams is
a common practice; (2) the majority of
recycle plants use surface water as their
source and are thereby at risk from
Cryptosporidium; (3) a large majority of
plants providing data recycle prior to
the point of primary coagulant addition,
and; (4) a majority of plants supplying
data provide treatment for recycle
waters prior to reintroducing them to
the treatment plant. The FAX survey.
provides an informative snapshot of
national recycle practices due to the
number of recycle plants it includes, the
geographic distribution of respondents,
and the good representation of plants
serving populations of less than 10,000
people.
ii. Options to recycle.
The FAX survey asked whether
feasible alternatives to recycle are
available (i.e., NPDES surface water
discharge permit, pretreatment permit
for discharge to POTW) and the
importance of recycle to optimizing
treatment performance and meeting
production requirements. Responses to
these questions is summarized in Table
IV.19.
Table IV.19 shows that approximately
20 percent of respondents could not
obtain either an NPDES surface water
discharge permit or a pretreatment
permit for discharge to a POTW.
Approximately 90 percent of
respondents stated that recycle flow is
not important to meet typical demand.
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Federal Register/Vol. 65, No. 69/Monday, April 10, 2000/Proposed Rules
Twenty-four percent of all respondents
stated that returning recycle to the
treatment process is important for
respondents may have considered not
changing current plant operation (e.g.,
not changing current recycle practice)
practice is important for the plant to
produce the highest quality finished
water.
optimal operation. "Optimal operation" an aspect of optimal treatment, rather
was not defined by the survey and
than addressing whether recycle
TABLE IV. 19.—OPTIONS TO RECYCLE AS REPORTED BY FAX SURVEY PLANTS'"
Question
Able to obtain NPDES surface discharge permit*?
Can obtain either an NPDES or a POTW discharge permit'?
Is recycle important to meet peak demand*? *
Is recycle important to meet typical demand1?
Is recycle important to optimal operation*? (All plants in survey)
Percent
Yes
41%
(n=131)
43%
(n=137)
60%
(n=192)
14%
(n=44)
9%
(n=28)
24%
(n=75)
13%
(n=3)
Percent
No
37%
(n=120)
42%
(n=136)
19.5%
(n=63)
80%
(n=257)
85%
(n=272)
70%
(n=225)
83%
(n=19)
Percent
Unknown
22%
(n=70)
15%
(n=48)
20.5%
(n=66)
6%
(n=20)
6%
(n=21)
6%
(n=21)
4%
(n=1)
1 Number of plants varies from question to question due to different response rates.
2 Optimal operation not defined by survey. May include overall plant operation rather than importance of recycle to producing highest possible
quality finished water.
iii. Conclusions
The ICR and FAX survey data are
complimentary, as the ICR data supplies
a wealth of data regarding recycle
practices at large capacity plants, while
the FAX Survey provides data on
recycle practices over a range of plant
capacities. Taken together, the two data
sets provide a good picture of current
recycle practice. The data indicate that
recycle is a common practice for plants
sampled. Approximately half of the
respondents providing data return
recycle flow to the treatment process
and 70 percent provide some type of
recycle treatment. Sedimentation and
equalization are the two most
commonly employed treatment
technologies for plants supplying data.
Approximately 80 percent of plants
sampled return recycle prior to the
point of primary coagulant addition.
Examining the recycle practices of
plants in the ICR and FAX survey data
show that small plants (f.e., fewer than
10,000 people served) are more than
twice as likely as large plants (i.e.,
greater than 100,000 people served) to
provide sedimentation for recycle
treatment (58 versus 26 percent).
The FAX survey responses show that
approximately half of plants providing
data have an option to recycle return,
whether it be an NPDES surface water
discharge permit or discharge to a
POTW. Eighty-five percent of
respondents stated that recycle flow is
not important to meet peak demand.
Less than a quarter of respondents have
monitored pathogen concentrations in
backwash water and fewer than half
have any monitoring data to
characterize the quality of the backwash
water.
3. Recycle Provisions for PWSs
Employing Rapid Granular Filtration
Using Surface Water or Ground Water
Under the Direct Influence of Surface
Water
a. Return Select Recycle Streams Prior
to the Point of Primary Coagulant
Addition
i. Overview and Purpose
Today's proposal requires that
systems employing rapid granular
filtration and using surface water or
GWUDI as a source return filter
backwash, thickener supernatant, and
liquids from dewatering processes to the
primary treatment process prior to the
point of primary coagulant addition.
The goal of this provision is to protect
the integrity of chemical treatment and
ensure these recycle streams are passed
through as many physical removal
processes as possible to provide
maximum opportunity for removal of
Cryptosporidium oocysts from the
recycle flow. Since Cryptosporidium is
resistant to standard disinfection
practice, it is important that chemical
treatment be optimized to protect
treatment plant efficiency and that all
available physical removal processes be
employed to remove it.
Today's proposal requires these flows
be returned prior to the point of primary
coagulant addition because these
streams are either of sufficient volume
to cause hydraulic disruption within the
treatment process when recycled and/or
are likely to contain Cryptosporidium
oocysts. Minor recycle streams, such as
lab sample lines, pump packing water,
and infrequent process overflows are
not likely to threaten plants' hydraulic
stability or contain appreciable numbers
of oocysts.
Treatment plant types that need to
return recycle to a location other .than
prior to the point of primary coagulant
addition to maintain optimal treatment
performance (optimal performance as
indicated by finished water or intra-
plant turbidity levels), plants that are
designed to employ recycle flow as an
intrinsic component of their operations,
plants with very low influent turbidity
levels that may need alternative recycle
locations to obtain satisfactory
suspended solids removal, or other
types of plants constrained by unique
treatment considerations, may apply to
the State to recycle at an alternative
location under today's proposal. Once
approved by the State, plants may
recycle to the specified location.
ii. Data
Data from the ICR and FAX Survey
indicate that 75 and 78 percent of
plants, respectively, return recycle prior
to the point of primary coagulant
addition. The "point of primary
coagulant addition" was defined in both
analyses as the return of recycle prior to
the rapid mix unit. The FAX Survey
data indicate that 77 percent of plants
serving under 10,000 people recycle
prior to the point of primary coagulant
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19111
addition. It also showed that 78 percent
percent of all plants in the database
return recycle there, which suggests that
plants serving smaller populations may
return recycle prior to the point of
primary coagulant addition as
frequently as plants serving larger
populations. Other common recycle
return locations are the rapid mix unit,
between rapid mix and clarification, or
into the clarification unit itself.
The Agency does not believe filter
backwash, thickeners supernatant, or
liquids from dewatering processes
should be recycled at the point of
primary coagulant addition or after it for
three reasons:
(l) Addition of these recycle streams,
which can contain residual coagulant
and other treatment chemicals, after the
location of primary coagulant addition,
may render the chemical dose applied
less effective, potentially harming the
efficiency of subsequent treatment
processes;
(2) Introduction of recycle into the
flocculation unit or clarification unit
may create hydraulic currents that
exacerbate or create short circuiting,
and;
(3) Recycle introduced into the
clarification process may not experience
sufficient residence time for adequate
solids removal to occur.
The Agency is concerned that plants
may not adjust chemical dosage during
recycle events to account for: (1) The
presence of a potentially significant
amount of residual treatment chemical
in recycle flow and changes in recycle
flow quality, and; (2) potentially large
fluctuations in plant influent flow
during recycle events. EPA is concerned
that changes in influent water quality
and flow are not monitored on an
instantaneous basis during recycle
events. Since the chemistry of the
recycle flow and source water may
differ significantly, it is important
plants mix source and recycle water to
establish a uniform chemistry prior to
applying treatment chemical so the dose
is appropriate for the mixture.
Additionally, wide fluctuation in plant
influent flow during recycle events may
cause chemical over-or under-dosing,
which can lower overall oocyst removal
efficiency. In an article concerning
optimization of filtration performance,
Lytle and Fox (1996) state, "The
capability to instantaneously monitor
treatment processes and rapidly and
effectively respond to raw and filter
effluent quality changes are important
factors in consistently producing low
turbidity water." Logdson (1987) further
states, "For a plant to be operated
properly, the total flow rate has to be
known on an instantaneous basis or by
volumetric measurement." EPA believes
it is important plants diligently monitor
the appropriateness of chemical dosing
at all times, but particularly during
recycle events, and strive for real-time
chemical dose and influent flow
management to optimize plant oocyst
removal.
Pilot-scale research conducted by
Patania et al. (1995) to examine the
optimization of filtration found that
chemical pretreatment was the most
important variable determining oocyst
removal by filtration. Edzwald and
Kelley (1998) performed pilot-scale
work to determine the ability of
sedimentation, DAF, and filtration to
remove Cryptosporidium and found that
coagulation is critical to effective
Cryptosporidium control by clarification
and filtration. Bellamy et al. (1993)
stated that the most important factor in
plant performance is the use of optimal
chemical dosages. Coagulation was
recognized as the single most important
step in the process of water clarification
by Conley (1965). Ten pilot scale runs
performed by Dugan et al. (1999)
showed that coagulation has a large
influence on the log removal of
Cryptosporidium achieved by
sedimentation. The importance of
proper coagulation to filter performance
was noted by Robeck et al. (1964) in
pilot and full-scale work that showed
proper coagulation is more important to
the production of safe water than the
filtration rate used. Results of direct
filtration pilot studies, summarized by
Trussell et al. (1980), showed that
"effective coagulant is absolutely
necessary if good effluent qualities are
to be consistently produced."
Given the critical role proper
chemical dosing plays in maintaining
effective clarification and filtration
processes, the Agency believes it is
prudent and necessary to minimize the
possibility recycle of spent filter
backwash, thickener supernatant, and
dewatering liquids will render chemical
dosages applied during recycle events
inaccurate, due to the presence of
residual chemical or variations in
influent flow, by requiring they be
returned prior to the point of primary^
coagulant addition.
Finally, a fundamental tenet of water
treatment is multiple treatment barriers
should be provided to prevent microbial
pathogens from entering finished water.
To achieve this, conventional plants
rely on coagulation, flocculation,
clarification, and filtration as preventive
microbial barriers. The Agency believes
it is important that recycle waters be
passed through each of these treatment
processes to maximize the probability
disinfection resistant oocysts will be
removed in the plant and not enter the
finished water supply.
iii. Proposed Requirements
Today's proposal requires that rapid
granular filtration plants using surface
water or GWUDI as a source return filter
backwash, thickener supernatant, and
liquids from dewatering processes prior
to the point of primary coagulant
addition. Plants that require an
alternative recycle return location to .
maintain optimal finished water quality
(as indicated by finished water or intra-
plant turbidity levels), plants that are
designed to employ recycle flow as an
intrinsic component of the treatment
process, or plants with unique treatment
requirements or processes may apply to
the State to return recycle flows to an
alternative location. Plants may utilize
this alternative location once granted by
the State. EPA will develop detailed
guidance and make it available to States
and PWSs.
Softening systems may recycle
process solids, but not spent filter
backwash, thickener supernatant, or
liquids from dewatering processes, at
the point of lime addition immediately
preceding the softening process to
improve treatment efficiency. Literature
establishes that return of process solids
to point of lime addition decreases
production of nuclei, increases the rate
of crystallization, and increases crystal
size, all of which enhance settling and
process integrity (Randtke, 1999;
Snoeyink and Jenkins, 1980). Contact
clarification systems may recycle
process solids, but not spent filter
backwash, thickener supernatant, or
liquids from dewatering processes,
directly into the contactor to improve
treatment efficiency.
iv. Request for Comments
EPA requests comment on the
proposed requirements. The Agency
also requests comment on the following
aspects of this provision:
(1) What regulatory options are
available to ensure direct recycle plants
practice real-time chemical dose and
influent flow management? Should
flow-paced coagulant feed be required at
direct recycle plants to minimize
potential harmful impacts of recycle?
What regulatory requirements may be
applicable to ensure the integrity of the
coagulation process?
(2) What treatment processes or
treatment configurations may need an
alternative recycle location to maintain
optimal treatment?
(3) What alternative recycle locations
are appropriate for such treatment
configurations and what location may
be inappropriate?
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Federal Register/Vol. 65, No. 69/Monday, April 10, 2000/Proposed Rules
(4) Are there other reasons, beyond
maintaining optimal treatment
efficiency, to justify granting alternate
recycle locations to plants? What are
they?
(5) What criteria, operating practices,
or other parameters should be evaluated
to determine whether an alternative
recycle return location should be
granted?
(6) Does recycling at the point of
primary coagulant addition, instead of
prior to it, provide assurance that an
appropriate dose of treatment chemicals
will be consistently applied during
recycle events? Is it necessary to mix the
recycle and raw water prior to chemical
addition to ensure a consistent water
chemistry for chemical dosing?
(7) Are there circumstances where it
would be appropriate to allow systems
to recycle at the point of primary
coagulant addition?
b. Recycle Requirements for Systems
Practicing Direct Recycle and Meeting
Specific Criteria
i. Overview and Purpose
Today's proposal requires that self
assessments be performed at
conventional filtration plants meeting
all of the following criteria and the
results of the self assessment reported to
the State. The criteria are:
(1) Use of surface water or GWUDI as
a source;
(2) Employ of 20 or fewer filters to
meet production requirements during
the highest production month in the 12
month period prior to LTlFBR's
compliance date, and;
(3) Recycle spent filter backwash or
thickener supernatant directly to the
treatment process (i.e., recycle flow is
returned within the treatment process of
a PWS without first passing the recycle
flow through a treatment process
designed to remove solids, a raw water
storage reservoir, or some other
structure with a volume equal to or
greater than the volume of spent filter
backwash water produced by one filter
backwash event.)
The goal of the self assessment is to
identify those direct recycle plants that
exceed their State approved operating
capacity, on an instantaneous basis,
during recycle events. Plants are
required to submit a monitoring plan to
the State prior to conducting the month
long self assessment monitoring. Results
of self assessment monitoring must be
reported to the State. The State is
required to determine, by reviewing the
self assessment, whether the plant's
current recycle practice should be
modified to protect plant performance
and provide an additional measure of
public health protection. The State is
required to report its determination for
each plant performing a self assessment
to EPA and briefly summarize the
reason(s) supporting each
determination.
EPA selected the three
aforementioned criteria to identify
plants required to perform a self
assessment for the following reasons.
First, surface or GWUDI source waters
may contain Cryptosporidium. Second,
the hydraulic impact of recycle to plants
typically employing more than 20 filters
to meet production requirements should
be dampened because plant influent
flow is of significantly greater
magnitude than the flow produced by a
backwash event. Third, plants that
practice direct recycle of filter backwash
and/or thickener supernatant may
exceed their operating capacity during
recycle events due to the large volume
of these streams.
ii. Data
Plants that recycle filter backwash
and thickener supernatant, directly,
without recycle flow equalization or
treatment, may exceed their operating
capacity during recycle events. Table
IV.20 illustrates the magnitude by
which direct recycle plants may exceed
their operating capacity during recycle
events. For purposes of the table,
operating capacity is assumed to be
either plant design flow or average flow
(see example below). The values in the
table are conservative, as they are likely
to over predict the factor by which
direct recycle plants will exceed
operating capacity during recycle
events. This conservatism is due to the
assumed filter backwash rate of 15 gpm/
ft2 and the assumed backwash duration
of 15 minutes, the minimum backwash
rate and duration recommended by the
Great Lakes-Upper Mississippi River
Board of State and Provincial Public
Health and Environmental Managers
(1997). Design and average flow values
assumed for plant operating capacity
were developed from equations
presented in EPA's baseline handbook
(1999g). For purposes of this example,
plant design and average flow are
assumed to equal State approved
operating capacity to illustrate the
potential for plants to exceed operating
capacity during recycle events. Relevant
equations and example calculations are
shown below.
Example
(1) Design to average ratios:
design flow < .25 mgd; ratio design flow :
average flow = 3.2:1
design flow > .25 mgd to 1 mgd; ratio design
flow : average flow = 2.8:1
design flow > 1 mgd to 10 mgd; ration design
flow : average flow = 2.4:1
design flow > 10 mgd; ratio design flow :
average flow = 2.0:1
(2) Maximum filter size: 700 sq./ft2 (EPA,
1998a)
(3) Backwash volume calculation:
Filter area (ft2) x 15 gpm/ft2 x 15 minutes =
volume of one backwash
(4) Design and average capacity exceedence
factors:
(Backwash flow -t- design (or average) flow)
-s- design flow = exceedence factor
(5) Percent Influent that is recycle:
Backwash flow •*• (Backwash flow + design
(or average flow)) = percent of influent that
is backwash
(6) Design flow = State approved operating
flow
TABLE IV.20.—IMPACT OF DIRECT RECYCLE
Design
flow
(MGD)
.033
.669
2.02
8.8
14.5
42.44
56.23
Number of
filters
2
4
6
8
10
18
24
Area of
one filter
(sq. ft)
5
50
100
320
425
700
700
Volume of
one back-
wash
(gallons)
1,125
11,250
22,500
72,000
95,625
157,500
157,500
Backwash
return flow
(15 minute
return;
gpm)
75
750
1,500
4,800
6,375
10,500
10,500
Design
flow
(gpm)
23
465
1,403
6,111
10,069
29,472
39,048
Average
flow
(gpm)
7
166
584
2,546
5,135
14,736
19,524
Factor de-
sign flow
is exceed-
ed by dur-
ing recycle
(at design
flow)
4.3
2.6
2.1
1.8
1.6
1.4
1.3
Percent in-
fluent that
is recycle
(at design
flow)
(percent)
77
62
52
44
39
26
21
Factor de-
sign flow
is exceed-
ed by dur-
ing recycle
(at aver-
age flow)
3.6
2.0
1.5
1.2
1.1
.86
.77
Percent in-
fluent that
is recycle
(at aver-
age flow)
(percent)
91
82
72
65
55
42
35
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19113
The purpose of Table IV. 20 is to
illustrate the impact direct recycle can
have on plant hydraulic loading and the
factor by which plant operating capacity
can be exceeded during recycle events.
As shown in Table IV.20, a plant with
two filters would process influent at
over three times its operating capacity
during a recycle event. Even if the plant
reduced or eliminated its raw water
influent flow for the duration of the
event, the remaining filter would be
subject to a loading rate that exceeds its
operating capacity, which could harm
finished water quality.
The amount of sedimentation basin or
clarification process storage available
during recycle events will have an
impact on the hydraulic loading to the
filters and the performance of the
sedimentation or clarification process.
The actual increase to filter loading
rates may be less than predicted in
Table IV.20 due to site-specific
conditions. However, the potential for
direct recycle plants to exceed operating
capacity is cause for concern because
oocyst removal can be compromised.
The Agency believes 20 filters is an
appropriate number for specifying
which plants are required to perform a
self assessment due to the results in
Table IV.20 and the above
considerations.
The importance of maintaining proper
plant hydraulics has been
acknowledged, notably by Logdson
(1987) who wrote, "Both the quantity
and quality of filtered water can be
affected by plant hydraulics. Maximum
hydraulic capacity is an obvious
limitation. The adverse influences of
rate of flow and flow patterns on water
quality may not be so obvious, but they
can be important." Fulton (1987)
recognized that short circuiting can
diminish the performance of settling
basins, cause overloading of filters, and
increase breakthrough of turbidity.
Other publications (Cleasby, 1990)
recognize that settled water quality
deteriorates when the surface loading
rate of sedimentation basins is
increased. Direct recycle practice can
give rise to short circuiting, cause plant
operating capacity to be exceeded, and
increase surface loading rates, all of
which can be detrimental to
Cryptosporidium removal.
Direct recycle practice can abruptly
increase filter loading rates, which has
been shown to lower filter performance.
Cleasby etal. (1963) performed
experimental runs with three pilot plant
filters by increasing the filtration rate
ten, twenty-five, and fifty-percent over
various time periods and monitoring the
passage of a target material during the
rate increase. Conclusions drawn from
the experiments were:
(l) Disturbance in filtration rate can
cause filters to pass previously
deposited material and the amount of
material passed is dependent on the
magnitude of the rate disturbance;
(2) More rapid disturbances cause
more material to be flushed through the
filter;
(3) The amount of material flushed
through the filter is independent, or
very nearly independent of
disturbance's duration, and;
(4) The amount of material flushed
through the filter following a
disturbance is dependent on the type of
material being filtered.
Pilot scale work was recently
performed by Glasgow and Wheatley
(1998) to investigate whether surges
affect filtrate quality. Effluent turbidity
and headloss within the filter media
were monitored for two pilot filter
columns that were surged at different
magnitudes. The results were compared
to control runs through the same pilot
columns to determine the effect of the
surge. Results indicated that surging
may significantly affect full scale filter
performance. Additional work is needed
to confirm these results.
Recent pilot scale work by McTigue et
al. (1998) examined the impact of
doubling the filter loading
instantaneously and gradually (over an
80 minute period) on pilot filters that
had been in operation for a period of
time or were "dirty." The experiments
showed that Cryptosporidium removal
achieved by the filters was lowered by
changes in filtration rate regardless of
whether loading rate was increased
instantaneously or gradually. In the
experiment, filter loading rates of 2
gpm/ft2 and 4 gpm/ft2 were doubled in
six separate test runs to determine
whether oocysts removal was affected.
Results showed that log removal of
oocysts was reduced by approximately
1.5 to 2.0 logs for when filter loading
rates of 2 gpm/ft2 and 4 gpm/ft2 were
either instantaneously and gradually
doubled. The report states, "These data
clearly demonstrate that any change in
filter loading rate on a filter that is dirty
presents a risk for breakthrough of
Giardia and Cryptosporidium to the
finished water, should these organisms
be present in the filter." Effluent
turbidity values remained low during
increases in filter loading rates but
particle count concentrations
immediately increased with increases in
loading rate. This may indicate that
turbidity is not a good indicator of
oocyst passage by dirty filters during
filtration rate increases.
Results of three other pilot runs from
the study showed that log removal of
oocysts did not change when the
influent oocyst concentration varied and
all other treatment conditions were held
constant. A four log removal of oocysts
was obtained for all three runs despite
influent oocyst concentrations of 4.610/
L, 688/L, and 26/L. The report states,
"This finding indicates that the risk for
passage of large numbers of cysts to the
finished water is greater when a water
treatment plant receives a highly
concentrated slug of cysts at its intake."
The Agency believes this is an
interesting conclusion, even though it is
based on a limited number of pilot runs.
If further pilot and full-scale work
verifies this finding, it indicates that log
removal of oocysts does not increase as
more oocysts are loaded to plant.
Recycle of flows containing oocysts
would therefore increase the number of
oocysts present in finished water,
relative to the number of oocysts that
would occur were recycle not practiced,
because plant treatment efficiency
would not increase to remove the
additional oocysts returned by recycle.
In summary, the Agency is concerned
that direct recycle of spent filter
backwash, thickener supernatant, and
liquids from dewatering process may
increase the risk of oocyst occurrence in
finished water for the following reasons:
(1) Sampling has established that
oocysts occur in finished water supplies
(see Table II.6 of this preamble);
(2) Data show that oocysts occur in
recycle streams;
(3) Literature indicates that
hydraulically overloading the
sedimentation process, as may happen
during direct recycle events, can harm
sedimentation performance;
(4) Literature indicates increasing or
abruptly changing filtration rates can
lead to more material passing through
filters, and;
(5) Recent pilot scale work by
McTigue et al. (1998) and Glasgow and
Wheatley (1998) indicates that filter
performance can be harmed by surges
and changes to filtration rate.
The Agency encourages the States to
closely examine recycle self assessments
performed by direct recycle plants to
determine whether direct recycle poses
an unacceptable risk to finished water
quality and public health and needs to
be modified due to the considerations
cited above.
Finally, EPA realizes that State
programs may use different
methodologies to set plant operating
capacity. States may also apply safety
factors of different magnitudes when
determining operating capacity. The
Agency does not believe it is
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appropriate to erode any safety factor or
margin of safety States provide when
setting operating capacity. Safety factors
are provided for a reason: to provide a
margin of safety to public health
protection efforts. The integrity and
magnitude of a safety factor should be
maintained, as it is in and of itself
integral to adequate public health
protection. The fact a safety factor is
applied when plant operating capacity
is set is not a justification, a priori, for
allowing plants to operate above said
operating capacity during recycle
events.
EPA also acknowledges that States
may use different methodologies to set
plant operating capacity. The Agency is
confident that the State programs, its
partners in public health protection, set
plant capacity to provide necessary
level of public health protection. The
fact that some State programs may set
plant operating capacities with different
methodologies likely reflects
geographical conditions and public
expectations unique to certain States
and sections of the country. EPA
believes methodologies employed by the
States results in establishment of
operating capacities necessary to protect
public health, meet regulatory
requirements, and satisfy unique
treatment needs and considerations
where they exist.
iii. Proposed Requirements
Self assessments must be performed at
plants meeting all of the following
criteria and the results of the self
assessment reported to the State:
(1) Use surface water or GWUDI as a
source and employ conventional rapid
granular filtration treatment;
(2) Employ of 20 or fewer filters to
meet production requirements during
the highest production month in the 12
month period prior to LTlFBR's
compliance date, and;
(3 j Recycle spent filter backwash or
thickener supernatant directly to the
treatment process [i.e., recycle flow is
returned within the treatment process of
a PWS without first passing the recycle
flow through a treatment process
designed to remove solids, a raw water
storage reservoir, or some other
structure with a volume equal to or
greater than the volume of spent filter
backwash water produced by one filter
backwash event).
Systems are required to develop and
submit a recycle self assessment
monitoring plan to the State no later
than three months after the rule's
compliance date for each plant the
requirements are applicable to. At a
minimum, the monitoring plan must
identify the month during which
monitoring will be conducted, contain a
schematic identifying the location of
raw and recycle flow monitoring
devices, describe the type of flow
monitoring devices to be used, and
describe how data from the raw and
recycle flow monitoring devices will be
simultaneously retrieved and recorded.
The self assessment of recycle
practices shall consist of the following
five steps:
(1) From historical records, identify
the month in the calendar year
preceding LTlFBR's effective date with
the highest water production.
(2} Perform the monitoring described
below in the twelve month period
following submission of the monitoring
plan to the State.
(3) For each day of the month
identified in (1), separately monitor
source water influent flow and recycle
flow before their confluence during one
filter backwash recycle event per day, at
three minute intervals during the
duration of the event. Monitoring must
be performed between 7:00 a.m. and
8:00 p.m. Systems that do not have a
filter backwash recycle event every day
between 7:00 am and 8:00 p.m. must
monitor one filter backwash recycle
event per day, any three days of the
•week, for each week during the month
of monitoring, between 7:00 a.m. and
8:00 p.m. Record the time filter
backwash was initiated, the influent and
recycle flow at three minute intervals
during the duration of the event, and the'
time the filter backwash recycle event
ended. Record the number of filters in
use when the filter backwash recycle
event is monitored.
(4) Calculate the arithmetic average of
all influent and recycle flow values
taken at three minute intervals in (3).
Sum the arithmetic average calculated
for raw water influent and recycle flows.
Record this value and the date the
monitoring was performed. This value is
referred to as event flow.
(5) After monitoring is complete,
order the event flow values in
increasing order, from lowest to highest,
and identify the monitoring events in
which plant operating capacity is
exceeded.
Systems are required to submit a self
assessment report to the State within
one month of completing the self
assessment monitoring. At a minimum,
the report must provide the following
information:
(1) All source and recycle flow
measurements taken and the dates they
were taken. For all events monitored,
report the times the filter backwash
recycle event was initiated, the flow
measurements taken at three minute
intervals, and the time the filter
backwash recycle event ended. Report
the number of filters in use when the
backwash recycle event is monitored.
(2) All data and calculations
performed to determine whether the
plant exceeded its operating capacity.
Report the number of event flows that
exceed State approved operating
capacity.
(3) A plant schematic showing the
origin of all recycle flows, the hydraulic
conveyance used to transport them, and
their final destination in the plant.
(4) A list of all the recycle flows and
the frequency at which they are
returned to the plant.
(5) Average and maximum backwash
flow through the filters and the average
and maximum duration of backwash
events in minutes, for each monitoring
event, and;
(6) Typical filter run length, number
of filters typically employed, and a
written summary of how filter run
length is determined (preset run time,
headloss, turbidity level).
EPA is proposing that the State review
all self assessments submitted by PWSs
and report to the Agency the below
information as it applies to individual
plants:
(1) A finding that modifications to
recycle practice are necessary, followed
by a brief description of the required
change and a summary of the reason(s)
the change is required, or;
(2) A finding that changes to recycle
practice are not necessary and a brief
description of the reason(s) this
determination was made.
The Agency also considered requiring
all recycle plants without existing
recycle flow equalization or treatment to
install recycle flow equalization. As
summarized in Table IV.21, several
recommendations for recycle
equalization and treatment have been
provided. However, these
recommendations are based on
theoretical calculations and/or limited
pilot-scale data that has not been
verified by full-scale plant performance
data. The Agency currently believes
insufficient data is available to
determine whether recycle flow
equalization is necessary to protect
finished water quality, and, if it is, the
level of equalization required to provide
protection to finished water supplies for
a wide variety of source water qualities,
treatment process types, and levels of
treatment effectiveness. The Agency
does not believe it is appropriate at this
time to propose a national recycle flow
equalization requirement for the
following reasons:
(l) Data on the occurrence of oocysts
in recycle streams, and their impact to
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19115
finished water quality upon recycle, is
very limited;
(2) Data that establishes the
magnitude of hydraulic disruption
caused by direct recycle events for a
variety of plant types, designs, and
operational practices has not been
identified; without this data, it is not
possible to quantify how much
treatment efficiency is reduced by the
hydraulic disruption and the number of
oocysts in the recycle flow that will
enter the finished water due to the
disruption. Without this information, it
is not possible to specify the level of
equalization necessary to control
hydraulic disruption for a variety of
plant configurations and operational
practices with any degree of certainty
and cost effectiveness, and;
(3) A uniform, national equalization
standard may not be appropriate
because it would not allow
consideration of site-specific factors
such as plant treatment efficiency,
loading capacity of clarification and
filtration units, source water quality,
and other site-specific factors that
influence the level of equalization a
plant may need to control recycle event
induced hydraulic disruption.
EPA believes some plants can realize
substantial benefit by installing recycle
flow equalization and will review data
to determine the need for an
equalization requirement when it
becomes available. The Agency requests
that commenters submit the following
pilot or full-scale data to assist its effort
to conduct a thorough analysis of
equalization based upon the best
available science:
(1) Data on the magnitude of
hydraulic disruption caused by recycle
events and its affect on finished water
turbidity and particle count levels;
(2) Data that correlate hydraulic
disruption to increased oocyst
concentration in finished water, and;
(3) Any other data commenters
believe that may be appropriate to
analyze the need for equalization, and;
(4) Whether the regulation should
require States to specify modifications
to recycle practice, for all plants that
exceed operating capacity during
monitoring, to ensure said plants'
remain below their State approved
operating capacity during recycle
events.
TABLE IV.21—RECOMMENDED EQUALIZATION PERCENTAGES
Source of recommendation •
Recommended Standards for Water Works Great Lakes Upper Mississippi
River Board of State and Provincial Public Health and Environmental Man-
agers. 1997. Albany: Health Education Services.
for Water Research Limited, United Kingdom (1994).
Recycle Stream Effects on Water Treatment. Comwell, D., and R. Lee. 1993.
Denver. AWWARF.
Equalization
Percentage
10%
10%
Use equalized,
continuous recy-
cle.
Is recycle treatment recommended?
No.
Yes. Turbidity less than 5.0 NTU or re-
sidual of 10mg/L suspended solids in
treated recycle flow.
Use proper waste stream treatment
prior to recycle.
«See the reference list at the end of the preamble for complete citations.
Finally, the Agency considered
requiring conventional filtration plants
that recycle within the treatment
process to provide sedimentation or
more advanced recycle treatment and
concluded a national treatment
requirement is inappropriate at this time
due data deficiencies. The Agency
believes the following data is necessary
to determine whether recycle flow
treatment is necessary to protect public
health and the requisite level of
treatment:
(1) Significant amounts of additional
data on the occurrence of oocysts for a
complete range of recycle streams
generated by a wide variety of source
water qualities, treatment plant types,
plant operational and recycle practices,
and plant treatment efficiencies;
(2) Data that correlates recycle stream
oocyst occurrence to finished water
occurrence;
(3) Additional data on the ability of
full-scale sedimentation basins to
remove oocysts during normal operation
and during recycle events. The Agency
has identified only three full-scale
studies, States eta/. (1995), Baudin and
Lame (1998), and Kelly et al (1995),
that allow quantification of oocyst
removal by sedimentation basins. Pilot
scale work, such as Edzwald and Kelley
(1998) and Dugan et al. (1999) is also
available, but the number of studies is
not extensive. The removal achieved by
sedimentation and other clarification
processes is critical for determining the
number of oocysts loaded to the filters,
the likely concentration of oocysts in
various recycle streams, and the impact
recycle may have on intra-plant oocyst
concentrations. Good oocyst removal in
the clarification process will remove a
large percentage of oocysts from recycle
and source water flows before they
reach the filters. The amount of removal
provided by primary clarification
therefore has a large influence on the
level of recycle flow treatment that may
be needed to mitigate risk to finished
water quality. Given that data on oocyst
removal by sedimentation and other
clarification processes is very limited,
the Agency does not believe it is
possible to assess the need for recycle
treatment and specify a minimum
treatment level that is meaningful for a
wide variety of plant types and recycle
practices;
(4) Data regarding the ability of DAF
and other clarification processes to
remove oocysts from recycle flow is
very limited. This data is important,
because the Agency anticipates plants
may respond to any recycle treatment
requirement by using DAF to treat
recycle flow because of the advantages
it provides relative to sedimentation.
However, EPA has only identified four
studies, Hall et al. (1995), Plummer et
al. (1995), Edzwald and Kelley (1998),
and Alvarez et al. (1999), that
determined the ability of DAF to remove
oocysts from source water.. One study,
by Gmbb et al. (1997), addresses the
ability of DAF to treat filter backwash
waters has been identified, but sampling
for oocyst removal was not performed,
although turbidity and color removal
were monitored and good results
obtained. Additional data is needed to
characterize the ability of DAF to
remove oocysts from recycle flow before
it can be used to meet any recycle
treatment requirement;
(5) Full-scale data on the ability of
sedimentation and other clarification
processes to remove oocysts from
recycle streams before they are returned
to the plant is very limited. EPA has
identified two studies, one by Cornwell
and Lee (1993) and a study by Karanis
et al. (1998) that provide data regarding
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sedimentation's ability to remove
oocysts from recycle flows. Additional
information is needed to establish lower
and upper bounds on the oocyst
removal sedimentation can achieve;
without this data, it is difficult to
specify a feasible level of oocyst
removal in a recycle flow treatment
requirement;
[6) Microfiltration and ultrafiltration
membranes appear to be very reliable at
removing Cryptosporidium from source
waters Qacangelo et al., 1995). However,
the Agency has identified limited data
regarding the ability of membranes to
effectively treat recycle flow, and
treatment of backwash with membranes
may not be appropriate at all locations
(Thompson et al., 1995) due to
incompatibility between membrane
filter material and residual treatment
chemical(s) in the backwash water.
Additional information regarding the
ability of microfiltration and
ultrafiltration membranes to treat
recycle flow is necessary to
comprehensively evaluate their
applicability, and;
(7) EPA is not aware of a surrogate,
including turbidity, particle counts, or
any other common and easy to measure
parameter, that can serve as an indicator
of the log removal of Cryptosporidium
recycle flow treatment units achieve.
The Agency does not believe it is
economically or technically feasible to
directly monitor oocyst removal by
treatment units. Without an accurate,
easy to measure surrogate for
Cryptosporidium removal, the Agency
does not believe it is possible to
ascertain the level of treatment recycle
flow treatment units achieve during
routine operations.
Given the above limiting factors, the
Agency does not believe it is prudent to
establish a national recycle flow
treatment requirement until additional
data becomes available. EPA requests
the following data be submitte'd:
(1) Data regarding intra-plant and
recycle stream occurrence of oocysts;
(2) Information on the ability of
individual treatment units of the
primary treatment train to remove
oocysts during normal, hydraulically
challenged, and suboptimal chemical
dose operations;
(3) Data on the ability of
sedimentation and other clarification
processes to remove oocysts from a wide
range of recycle streams;
(4) Data on the compatibility of
specific ultrafiltration and
microfiltration membrane materials
with residual chemicals that occur in
recycle streams and data regarding the
performance of these membrane
materials at full and pilot scale, and;
(5) Information on potential
surrogates that can be easily measured
and can accurately establish the log
removal of oocysts removed by recycle
flow treatment processes.
iv. Request for Comments
EPA requests comment on the
proposed requirements. The Agency
also requests comment on the following:
(1) What other parameters could be
monitored or what otiier overall
monitoring schemes could be employed
to assess whether a plant is exceeding
its operating capacity?
(2) What data should the plant report
to the State as part of its self assessment,
beyond the monitoring data and other
information listed above?
(3) Is monitoring during the highest
flow month appropriate? Is monitoring
during additional months necessary? Is
daily monitoring necessary or would
less frequent monitoring during the
month be sufficient?
(4) Should systems be required to
monitor and report turbidity
measurements from a representative
filter taken immediately preceding and
after recycle events monitored during
the self assessment to help characterize
the impact of recycle on plant
performance?
(5) Is limiting the self assessment to
plants with 20 or less filters
appropriate? Should the number of
filters be less or greater than 20? What
is the appropriate number of filters?
(6) Should systems be required to
monitor sedimentation overflow rates or
clarification loading rates while the
recycle flow monitoring is performed?
(7) EPA requests comment on criteria
that may identify recycle plants that
could receive substantial benefit from
implementing recycle equalization or
treatment as a standard practice.
(8) What type and amount of data is
required to determine whether recycle
flow equalization would provide a
benefit to finished water quality? What
methodology could be used to
determine an appropriate recycle flow
equalization percentage, and how
relevant are turbidity and particle
counts, at various locations in a plant,
to assessing an appropriate equalization
percentage for a single plant or a plant
type?
d. Requirements for Direct Filtration
Plants that Recycle Using Surface Water
or GWUDI
i. Overview and Purpose
Today's proposal requires direct
filtration plants that recycle to report to
the State whether flow equalization or
treatment is provided for recycle flow
prior to its return to the treatment
process. The purpose of today's
proposed requirement is to assess
whether the existing recycle practice of
direct filtration plants addresses
potential risks. The Agency believes that
direct filtration plants need to remove
oocysts from recycle flow prior to
reintroducing it to the treatment
process.
ii. Data
Twenty-three direct filtration plants
that used surface water responded to the
FAX Survey (AWWA, 1998). In the FAX
survey, plants could report whether
they provide recycle flow equalization,
sedimentation, or some other type of
treatment. Of the respondents, 21
reported providing treatment for the
recycle flow and two plants reported
providing only equalization. In the ICR
database, there were 23 direct filtration
plants and fourteen of them recycled to
the treatment process. All fourteen
plants provide recycle treatment. It is
not possible to determine the level of
oocyst removal FAX survey and ICR
plants achieve with available data.
The treatment train of a direct
filtration plant does not have a
clarification process to remove
Cryptosporidium before they reach the
filters; all oocyst removal is achieved by
the filters. If recycle flow treatment is
not provided, all of the oocysts captured
in the filters will be returned to the
treatment process in the recycle flow.
Because a primary clarification process
is not present to remove recycled
oocysts, they are caught in a closed
"loop" from which the only exit is
passage through the filters into the
distribution system. The Agency
believes direct filtration plants should
provide solids removal treatment for
recycle flows to limit the number of
oocysts returned to the treatment plant.
iii. Proposed Requirements
EPA is proposing that PWSs using
direct filtration that recycle to the
treatment process and utilize surface
water or GWUDI as a source report data
to the State that describes their current
recycle practice. Plants should report
the following information to the State:
(l) Whether recycle flow treatment or
equalization is in place;
(2) The type of treatment provided for
the recycle flow;
(3) If equalization, sedimentation, or
some type of clarification process is
used, the following information should
be provided: a) physical dimensions of
the unit (length, width, (or
circumference) depth,) sufficient to
allow calculation of volume and the
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19117
type, typical dose, and frequency with
which treatment chemicals are used;
(4) The minimum and maximum
hydraulic loading the treatment unit
experiences, and;
(5) Maximum backwash rate,
duration, typical filter run length, and
the number of filters at the plant.
The State should use the above
information to determine which plants
need to modify recycle practice to
provide additional public health
protection. States are required to report
to EPA whether they required
individual direct filtration plants to
modify recycle practice and provide a
brief explanation of the reason(s) for the
decision.
The Agency also considered requiring
that all direct filtration plants provide a
specific level of treatment for the
recycle flow. However, data necessary to
determine the appropriate level of
treatment is unavailable. Specifically,
the following data is needed:
(1) Data on the on the occurrence of
oocysts in. the spent filter backwash of
direct filtration plants. Direct filtration
plants generally use higher quality
source water than conventional plants
(AWWA, 1990) and it would be
inaccurate to use spent filter backwash
occurrence data from conventional
plants to assess the level of treatment
direct recycle plants may need;
(2) Data regarding the ability of
sedimentation and other clarification
processes to remove oocysts from
recycle flows is needed to determine
what may be a feasible level of
treatment. This data need was treated to
a detailed discussion in the previous
section of the preamble;
(3) An easy to measure and accurate
surrogate for oocyst removal is currently
unavailable; without such a surrogate, it
is not feasible to monitor the
performance of recycle treatment units,
and;
(4) Data on the applicability of
microfiltration and ultrafiltration for
treating spent filter backwash produced
by direct filtration plants. This data
need was discussed in detail in the
previous section.
Given the lack of oocyst occurrence
data for direct filtration recycle streams,
and limited knowledge of the level of
treatment clarification processes can
achieve, the Agency does not currently
believe it is possible to identify a
treatment standard for direct filtration
plants.
iv. Request for Comments
EPA requests comment on the
proposed requirements. The Agency
also requests comment on the following:
(1) Whether direct filtration plants
should be required to provide treatment
for recycle flows;
(2) The level of treatment direct
filtration plants should achieve;
(3) Data that establishes turbidity,
particle counting, or some other
surrogate as an appropriate indicator of
oocyst removal achieved by recycle
treatment units, and;
(4) Data on the ability of clarification
processes to remove oocysts and criteria
that can be used to determine the
applicability of specific membrane
materials for treatment of spent filter
backwash produced by direct filtration
plants.
d. Request for Additional Comment .
EPA requests comment on the
following:
(1) Should the recycle of untreated
clarification sludges be allowed to
continue, or should the Agency ban this
practice? What affect would a ban have
on the operation of specific plant types,
such as softening plants?
(2) Is it appropriate to apply
regulatory requirements to the
combined recycle flow rather than
stipulating requirements for individual
recycle flows? Which flows should be
regulated individually and why?
V. State Implementation and
Compliance Schedules ,
This section describes the regulations
and other procedures and policies States
have to adopt, or have in place, to
implement today's proposed rule. States
must continue to meet all other
conditions of primacy in 40 CFR part
142.
Section 1413 of the SDWA establishes
requirements that a State or eligible
Indian tribe must meet to maintain
primary enforcement responsibility
(primacy) for its public water systems.
These include: (1) Adopting drinking
water regulations that are no less
stringent than Federal NPDWRs in effect
under sections 1412(a) and 1412(b) of
the Act, (2) adopting and implementing
adequate procedures for enforcement,
(3) keeping records and making reports
available on activities that EPA requires
by regulation, (4) issuing variances and
exemptions (if allowed by the State)
under conditions no less stringent than
allowed by sections 1415 and 1416, and
(5) adopting and being capable of
implementing an adequate plan for the
provision of safe drinking water under
emergency situations.
40 CFR part 142 sets out the specific
program implementation requirements
for States to obtain primacy for the
public water supply supervision
program, as authorized under section
1413 of the Act. In addition to adopting
the basic primacy requirements, States
may be required to adopt special
primacy provisions pertaining to a
specific regulation. These regulation-
specific provisions may be necessary
where implementation of the NPDWR
involves activities beyond those in the
generic rule. States are required by 40
CFR 142.12 to include these regulation-
specific provisions in an application for
approval of their program revisions.
These State primacy requirements apply
to today's proposed rule, along with the
special primacy requirements discussed
below.
To implement today's proposed rule,
States are required to adopt revisions to
§ 141.2—definitions; § 141.32—public
notification; § 141.70—general
requirements; § 141.73—filtration;
§ 141.76—recycle; § 141.153—content of
the reports; § 141.170—general
requirements; § 142.14—records kept by
States; § 142.16—special primacy
requirements; and a new subpart T,
consisting of § 141.500 to § 141.571.
A. Special State Primacy Requirements
In addition to adopting drinking water
regulations at least as stringent as the
Federal regulations listed above, EPA
requires that States adopt certain
additional provisions related to this
regulation to have their program
revision application approved by EPA.
This information advises the regulated
community of State requirements and
helps EPA in its oversight of State
programs. States which require without
exception subpart H systems (all public
water systems using a surface water
source or a ground water source under
the direct influence of surface water) to
provide filtration, need not demonstrate
that the State program has provisions
that apply to systems which do not
provide filtration treatment. However,
such States must provide the text of the
State statutes or regulations which
specifies that public water systems
using a source water must provide
filtration.
EPA is currently developing, with
stakeholders input, several guidance
documents to aid the States and water
systems in implementing today's
proposed rule. This includes guidance
for the following topics: Disinfection
benchmarking and profiling, Turbidity,
and Filter Backwash and Recycling.
EPA will also work with States to
develop a State implementation
guidance manual.
To ensure that the State program
includes all the elements necessary for
a complete enforcement program, the
State's application must include the
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following in order to obtain EPA's
approval for implementing this rule:
fl) Adoption of the promulgated
LT1FBR.
(2) Description of the procedures the
State will use to determine the adequacy
of changes in disinfection process by
systems required to profile and
benchmark under § 142.16(h)(2)(ii) and
how the State will consult with PWSs
to approve modifications to disinfection
practice.
(3) Description of existing or adoption
of appropriate rules or other authority.
under § 142.16(h)(l) to require systems
to participate in a Comprehensive
Technical Assistance (CTA) activity,
and the performance improvement
phase of the Composite Correction
Program (CCP).
(4) Description of how the State will
approve a method to calculate the logs
of inactivation for viruses for a system
that uses either chloramines or ozone
for primary disinfection.
(5) For filtration technologies other
than conventional filtration treatment,
direct filtration, slow sand filtration or
diatomaceous earth filtration, a
description of how the State will
determine under § 142.16(h)(2)(iii), that
a public water system may use a
filtration technology if the PWS
demonstrates to the State, using pilot
plant studies or other means, that the
alternative filtration technology, in
combination with the disinfection
treatment that meets the requirements of
Subpart T of this title, consistently
achieves 99.9 percent removal and/or
inactivation of Giardia lamblia cysts and
99.99 percent removal and/or
inactivation of viruses, and 99 percent
removal of Cryptosporidium oocysts;
and a description of how, for the system
that makes this demonstration, the State
will set turbidity performance
requirements that the system must meet
95 percent of the time and that the
system may not exceed at any time a
level that consistently achieves 99.9
percent removal and/or inactivation of
Giardia lamblia cysts, 99.99 percent
removal and/or inactivation of viruses,
and 99 percent removal of
Cryptosporidium oocysts.
(6) Description of the criteria the State
will use under § 142.16(b)(2)(vi) to
determine whether public water systems
completing self assessments under
§ 141.76 (c) are required to modify
recycle practice and the criteria that will
be used to specify modifications to
recycle practice.
(7) Description of the criteria the State
will use under § 142.16(b)(2)(vii) to
determine whether direct filtration
systems reporting data under § 141.76
(d) are required to change recycle
practice and the criteria that will be
used to specify changes to recycle
practice.
(8) The application must describe the
criteria the State will use under
§ 142.16(bH2Hviii) to determine whether
public water systems applying for a
waiver to return recycle to a location
other than prior to the point of primary
coagulant addition, will be granted the
waiver for an alternative recycle
location.
B. State Recordkeeping Requirements
Today's rule includes changes to the
existing record-keeping provisions to
implement the requirements in today's
proposed rule. States must maintain
records of the following: (1) Turbidity
measurements must be kept for not less
than one year;
(2) disinfectant residual
measurements and other parameters
necessary to document disinfection
effectiveness must be kept for not less
than one year; (3) decisions made on a
system-by-system basis and case-by-case
basis under provisions of part 141,
subpart H or subpart P or subpart T; (4]
records of systems consulting with the
State concerning a modification of
disinfection practice (including the
status of the consultation);
(5) records of decisions that a system
using alternative filtration technologies
can consistently achieve a 99 percent
removal of Cryptosporidium oocysts as
well as the required levels of removal
and/or inactivation of Giardia and
viruses for systems using alternative
filtration technologies, including State-
set enforceable turbidity limits for each
system. A copy of the decision must be
kept until the decision is reversed or
revised and the State must provide a
copy of the decision to the system, and;
(6) records of systems required to do
filter self-assessments, CPE or CCP.
These decision records must be kept for
40 years (as currently required by
§ 142.14 for other State decision
records) or until a subsequent
determination is made, whichever is
shorter.
C. State Reporting Requirements
Currently States must report to EPA
information under 40 CFR 142.15
regarding violations, variances and
exemptions, enforcement actions and
general operations of State public water
supply programs. Today's proposal
requires States to report a list of direct
recycle plants performing self
assessments, whether the State required
these systems to modify recycle
practice, and the reason(s)modifications
were or were not required and a list of
direct filtration plants performing self
assessments, whether the State required
these systems to modify recycle
practice, and the reason(s) modifications
were or were not required
D. Interim Primacy
On April 28, 1998, EPA amended its
State primacy regulations at 40 CFR
142.12 (63 FR 23362) (EPA 1998i) to
incorporate the new process identified
in the 1996 SDWA amendments for
granting primary enforcement authority
to States while their applications to
modify their primacy programs are
under review. The new process grants
interim primary enforcement authority
for a new or revised regulation during
the period in which EPA is making a
determination with regard to primacy
for that new or revised regulation. This
interim enforcement authority begins on
the date of the primacy application
submission or the effective date of the
new or revised State regulation,
whichever is later, and ends when EPA
makes a proposed determination.
However, this interim primacy authority
is only available to a State that has
primacy for every existing national
primary drinking water regulation in
effect when the new regulation is
promulgated.
As a result, States that have primacy
for every existing NPDWR already in
effect may obtain interim primacy for
this rule, beginning on the date that the
State submits its final application for
primacy for this rule to EPA, or the
effective date of its revised regulations,
whichever is later. Interim primacy is
available for the following rules:
• Stage 1 Disinfectants and
Disinfection Byproducts Rule
(December 16, 1998)(EPA,1998c)
• Interim Enhanced Surface Water
Treatment Rule (EPA,1998a)
• Consumer Confidence Report Rule
(EPA, 1998f)
• Variances and Exemptions Rule
(EPA, 1998g)
• Drinking Water Contaminant
Candidate List (EPA, 1998h)
• Revisions to State Primacy
Requirements (EPA,1998i)
• Public Notification Rule (EPA,
1999i)
In addition, a State which wishes to
obtain interim primacy for future
NPDWRs must obtain primacy for this
rule. After the effective date of the final
rule, any State that does not have
primacy for this rule cannot obtain
interim primacy for future rules.
E. Compliance Deadlines
Section 1412(b)(10) of SDWA
provides that drinking water rules
become effective 36 months after
promulgation unless the Administrator
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determines that an earlier time is
practicable. The Administrator may also
extend the effective date by an
additional 24 months if capital
improvements are necessary. The
Agency believes the three year effective
date is appropriate for all of the
provisions in today's notice except for
those provisions that address the return
of recycle flows. The Agency believes
providing a five year compliance period
for systems making modifications to
recycle practice is appropriate and
warranted under 1412(b)(10). To
effectively modify recycle practice,
capital improvements, such as installing
additional equipment and/or
constructing new facilities, will likely
be required. Specific examples of
potential capital improvements are
installing new piping and pumps to
convey recycle flow prior to the point of
primary coagulant addition and
constructing equalization basins or
recycle flow treatment facilities. A
limited number of systems may be able
to make operational modifications, per
the State's determination, that will
effectively address potential risks.
However, the Agency believes the great
majority of systems required to either
relocate their recycle return location or
modify recycle practice as directed by
the State will need to perform capital
improvements. The capital
improvement process is lengthy;
systems will need to engage in
preliminary planning activities, consult
with State and local officials, develop
engineering and construction designs,
obtain financing, and construct the
facilities. The Agency believes the
widespread need that systems making
modifications to recycle practice will
have for capital improvements warrants
the additional 24 months for
compliance purposes. The Agency
solicits comment on the appropriateness
of providing an additional two years for
compliance with the recycle provisions.
EPA seeks comment on extending the
compliance deadline an extra two years
because systems are expected to make
capital improvements to address recycle
practice. EPA also seeks comment on a
similar two year extension to comply
with the turbidity provisions of today's
proposed rule.
II. Economic Analysis
This section summarizes the Health
Risk Reduction and Cost Analysis in
support of the Long Term 1 Enhanced
Surface Water Treatment and Filter
Backwash Rule (LT1FBR) as required by
Section 1412(b)(3}(C) of the 1996
Amendments to the SDWA. In addition,
under Executive Order 12866,
Regulatory Planning and Review, EPA
must estimate the costs and benefits of
LTlFBR in a Regulatory Impact
Analysis (RIA) and submit the analysis
to the Office of Management and Budget
(OMB) in conjunction with publication
of the proposed rule. EPA has prepared
an RIA to comply with the requirements
of this Order and the SDWA Health Risk
Reduction and Cost Analysis (EPA,
1999h). The RIA has been published on
the Agency's web site, and can be found
at http://www.epa.gov/safewater. The
RIA can also be found in the docket for
this rulemaking.
The goal of the following section is to
provide an analysis of the costs,
benefits, and other impacts of the
proposed rule to support future
decisions regarding the development of
the LTlFBR.
A. Overview
The analysis for this rule examines
the costs and benefits for five rule
provisions: filter effluent turbidity,
applicability monitoring, disinfection
benchmark profiling, uncovered finish
water reservoirs, and recycle. Several
options were considered for each
provision. Costs were estimated for
three individual turbidity options, three
profiling options, and three
applicability monitoring options. In
addition, costs were estimated for four
different recycle options. All four
recycle options require spent filter
backwash, thickener supernatant, and
liquids from dewatering be returned to
the treatment process prior to the point
of primary coagulant addition. The
extent of modifications to recycle
practice varies among the rule options.
The value of health benefits from the
turbidity provision was estimated for
the preferred option. The benefits from
the other rule provisions are described
qualitatively. Several non-health
benefits from this rule were also
considered by EPA but were not
monetized. The non-health benefits of
this rule include: avoided outbreak
response costs and possibly reduced
uncertainty and averting behavior costs.
By adding the non-monetized benefits
with those that are monetized, the
overall benefits of these rule options
increase beyond the dollar values
reported.
Additional analysis was conducted by
EPA to look at the incremental impacts
of the various rule options, impacts on
households, benefits from reductions in
co-occurring contaminants, and possible
increases in risk from other
contaminants. Finally, the Agency
evaluated the uncertainty regarding the
risk, benefits, and cost estimates.
B. Quantifiable and Non-Quantifiable
Costs
In estimating the costs of each rule
option, die Agency considered impacts
on public water systems and on States
(including territories and EPA
implementation in non-primacy States).
The LTlFBR will result in increased
costs to public water systems for
improved turbidity treatment,
applicability monitoring, disinfection
benchmarking, covering new finished
water reservoirs and modification to
recycle practice. States will also face
implementation costs. Most of the
provisions of this rule, except the
recycle provision, apply to systems
using surface water or ground water
under the direct influence of surface
water that serve less than 10,000 people.
The recycle provisions, however, apply
to all surface water systems that recycle
filter backwash, thickener supernatant,'
or liquids from dewatering.
1. Total Annual Costs
EPA estimates that the annualized
cost of the preferred alternatives for the
proposed rule will be $97.5 million.
This estimate includes capital costs for
treatment changes and start-up labor
costs for monitoring and reporting
activities that have been annualized
assuming a 7% discount rate and a 20-
year amortization period. Other cost
estimates reported in this section also
use these same amortization
assumptions. The estimated cost of the
preferred alternatives also includes
annual operating and maintenance costs
for treatment changes and annual labor
for turbidity monitoring activities.
The turbidity provisions (including
treatment changes, monitoring, and
exceptions reporting) account for 70%
($68.6million annually) of total costs
and the recycling provisions (i.e.,
recycle to headworks, self assessment,
and direct filtration) account for 25%
($24.5 million annually) of total costs.
Utility expenditures for all provisions
equal almost 93% ($90.2 million
annually) of total costs; State
expenditures make up the other 7%
($6.7 million annually).
To reduce the potential cost to small
systems, EPA developed and evaluated
the cost implications of several
regulatory alternatives for four of the
proposed LTlFBR provisions:
individual filter turbidity monitoring,
applicability monitoring, disinfection
benchmark profiling, and recycle. Many
of these alternatives reduce the labor
burden on small systems relative to
what it would be if the proposed rule
used the same requirements as IESWTR.
The total national costs previously
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discussed only included the costs of the
preferred alternatives. The following
section will describe the cost estimates
for each provision and discuss the cost
of other alternatives that were
considered.
2. Annual Costs of Rule Provisions
The national estimate of annual utility
costs for the proposed turbidity
provisions is based on estimates of
system-level costs for the various
provisions of the rule and estimates of
the number of systems expected to incur
each type of cost. The following
paragraphs describe the cost estimates
for each of the rule provisions.
Turbidity Provision Costs
The turbidity provisions are estimated
to cost $69.0 million annually. This cost
is associated with three primary
activities that result from this provision:
treatment changes, monitoring, and
exceptions reporting.
The treatment costs associated with
meeting the revised turbidity standard
of 0.3 NTU or less are the main costs
associated with the turbidity provision.
EPA estimates that 2,406 systems will
modify their turbidity treatment in
response to this rule. These costs are
estimated to be $52.2 million annually.
O&M expenditures account for 59% of
annual costs and the remain 41%
percent is annualized capital costs.
In addition to the turbidity treatment
costs, turbidity monitoring costs apply
to all small surface water or GWUDI
systems using conventional or direct
filtration methods. There are an
estimated 5,896 systems that fall under
this criteria. EPA estimated the costs to
utilities for three turbidity monitoring
alternatives. Alternative B, the preferred
alternative, excludes the exceptions
report for an individual filter exceeding
0.5 NTU in two consecutive
measurements, enabling systems to shift
from daily to weekly analysis and
review of the monitoring data. The
annualized individual filter turbidity
cost to public water systems for this
preferred option is approximately $10.1
million. In contrast, under the IESWTR
monitoring requirements of Alternative
A, small systems would expend $63.3
million annually for turbidity
monitoring. Alternative C, which only
requires monthly analysis is estimated
to cost $5.6 million annually. The total
state turbidity start-up and monitoring
annual costs are $4.98 million annually
and is assumed to be the same for all of
the three alternatives.
In addition to the turbidity treatment
and monitoring costs, individual filter
turbidity exceptions are estimated to
cost utilities $120 thousand annually for
the preferred option. State costs will be
approximately $1.17 million. This cost
includes the annual exception reports
and annual individual filter self.
assessment costs. Costs are slightly
higher for the other two alternative
individual filter turbidity monitoring
options because they result in increased
number of exception reports.
Disinfection Benchmarking Costs
Disinfection benchmarking involves
three components: profiling,
applicability monitoring, and
benchmarking. Four options were
costed for applicability monitoring.
Alternative 3, which uses the critical
monitoring period, is estimated to cost
less than $0.4 million annually. This is
substantially lower than the $6.0
million estimated for Alternative 1,
which has the same requirements as
IESWTR. Alternative 2 requires
sampling once per quarter for 4 quarters
for systems serving 501-10,000, but
allows systems under 500 to sample
once during the critical monitoring
period. This option has an annualized
cost of $1.1 million. The preferred
option, Alternative 4, makes it optional
to sample during the critical monitoring
period and is estimated to cost $0.04
million annualized.
Three options were considered for
disinfection profiling and
benchmarking. They differed in the
frequency and duration of data
collection. The preferred alternative,
Alternative 2, requires weekly
monitoring for one year and is estimated
to have an annualized cost of $0.8
million. In comparison, Alternative 1
which requires daily data collection for
one year, has an annualized cost of
approximately $1.3 million. The final
option, Alternative 3, requires daily
monitoring for 1 month and has an
estimated annualized cost of $0.5
million.
State disinfection benchmarking
annualized costs are estimated to be
$0.4 million. This estimate includes
start-up, compliance tracking/
recordkeeping, and benchmark related
costs.
Covered Finished Water Reservoir
Provision Costs
The proposed LT1FBR requires that
new systems cover all finished water
reservoirs, holding tanks, or other
storage facilities for finished water.
Historical construction rates suggest that
new reservoirs over the next 20 years
will roughly equal to five percent of the
existing number of systems. Assuming
then that 580 new uncovered finished
water reservoirs would be built in the
next 20 years, total annual costs,
including annualized capital costs and
one year of O&M costs are expected to
be $2.6 million for this provision using
a 7% discount rate. This estimate is
calculated from a projected construction
rate of new reservoirs and unit cost
assumptions for covering new finished
water reservoirs.
Recycle Provision Cost
EPA considered four different
regulatory options for recycle. Each of
the four options requires spent filter
backwash, thickener supernatant, and
liquids from dewatering be returned
prior to the point of primary coagulant
addition. Alternative 1, is estimated to
result in an annualized cost of $16.7
million. Of the total costs of this
alternative, State start-up and review
costs for this alternative are only $20 to
$30 thousand annually.
Alternative 2, the preferred option,
further requires that conventional rapid
granular filtration plants using surface
water or GWUDI perform a self
assessment if they recycle spent filter
backwash and thickener supernatant,
employ 20 or less filters, and practice
direct recycle (treatment for the recycle
flow or equalization in a basin that has
a volume equal to the volume of spent
filter backwash produced by a single
filter backwash event is not provided).
The results of the self assessment are
reported to the State, and it specifies
whether modifications to recycle
practice are necessary. PWSs are
required to implement the modification
specified by the State. Under
Alternative 2, direct filtration plants are
required to submit data to the State on
current recycle practice, and the State
specifies whether changes to recycle
practice are required. The total
annualized cost of Alternative 2 is $17.4
to $24.5 million. $0.4 to $5.9 million of
the total annualized cost is for the direct
recycle component, $0.1 to $1.7 million
is for the direct filtration component,
and the remaining cost is for the
requirement to return recycle prior to
the point of primary coagulant addition.
Of the total costs of this alternative,
State start-up, review, and self
assessment costs for this alternative is
only $115 thousand annually.
Alternative 3 contain the same
requirements for direct filtration plants
and also requires the three recycle flows
mentioned above be returned prior to
the point of primary coagulant addition.
Direct recycle plants are required to
install equalization basins with a
volume equal to or greater than the
volume produced by two filter
backwash events. The annualized cost
of Alternative 3 is $55.0 to $56.7
million. Of this range, $38.1 million of
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the annualized cost is directly
associated with requiring direct recycle
plants to install equalization, and $0.1
to SI.7 million is associated with the
direct filtration component. State start-
up and self assessment costs for this
alternative is $95 thousand annually.
Alternative 4 requires the three
recycle flows mentioned above be
returned prior to the point of primary
coagulant addition and also requires
that all systems that recycle
(conventional and direct systems) install
sedimentation basins for recycle flow
treatment. Systems may also install
recycle flow treatment technologies that
provide treatment capability equivalent
or superior to sedimentation. For cost
estimation purposes, sedimentation
basins with tube settlers and polymer
addition where used. The Agency
approximated the annualized costs of
this option to be $151.8 million. The
sedimentation basin treatment
requirement for conventional and direct
filtration plants is 88% ($133.3 million)
of the total annualized cost of
Alternative 4. State start-up and self
assessment costs for this alternative is
$100 thousand annually.
3. Non-Quantifiable Costs
Although EPA has estimated the cost
of all the rule's components on drinking
water systems and States, there are some
costs that the Agency did not quantify.
These non-quantifiable costs result from
uncertainties surrounding rule
assumptions and from modeling
assumptions. For example, EPA did not
estimate a cost for systems to acquire
land if they needed to build a treatment
facility or significantly expand their
current facility. This was not costed
because many systems will be able to
construct new treatment facilities on
land already owned by the utility. In
addition, if the cost of land was
prohibitive, a system may choose
another lower cost alternative such as
connecting to another source. A cost for
systems choosing this alternative is
unquantified in our analysis.
C. Quantifiable and Non-Quantifiable
Health Benefits
The primary benefits of today's
proposed rule come from reductions in
the risks of microbial illness from
drinking water. In particular, LTlFBR
focuses on reducing the risk associated
with disinfection resistant pathogens,
such as Cryptosporidium. Exposure to
other pathogenic protozoa, such as
Giardia, or other waterborne bacteria,
viral pathogens, and other emerging
pathogens are likely to be reduced by
the provisions of this rule as well but
are not quantified. In addition, LTlFBR
produces nonquantifiable benefits
associated with the risk reductions that
result from the recycle provision,
uncovered reservoirs provision,
including Cryptosporidium in GWUDI
definition, and including
Cryptosporidium in watershed
requirements for unfiltered systems.
1. Quantified Health Benefits
a. Turbidity Provisions
The quantification of benefits from
this rule is focused solely on reductions
in the risk of cryptosporidiosis.
Cryptosporidiosis is an infection caused
by Cryptosporidium which is an acute,
self-limiting illness lasting 7 to 14 days
with symptoms that include diarrhea,
abdominal cramping, nausea, vomiting
and fever (Juranek, 1995). The cost of
illness avoided of cryptosporidiosis is
estimated to have a mean of $2,016
(Harrington et al., 1985; USEPA 1999h)
The benefits of the turbidity
provisions of LTlFBR come from
improvements in filtration performance
at water systems. The benefits analysis
attempts to take into account some of
the uncertainties in the analysis by
estimating benefits under two different
current treatment and three improved
removal assumptions. The benefits
analysis also used Monte Carlo
simulations to derive a distribution of
estimates, rather than a single point
estimate.
The benefits analysis focused on
estimating changes in incidence of
cryptosporidiosis that would result from
the rule. The analysis included
estimating the baseline (pre-LTlFBR)
level of exposure from Cryptosporidium
in drinking water, reductions in such
exposure resulting from treatment
changes to comply with the LTlFBR,
and resultant reductions of risk.
Baseline levels of Cryptosporidium in
finished water were estimated by
assuming national source water
occurrence distribution (based on data
by LeChevallier and Norton, 1995) and
a national distribution of
Cryptosporidium removal by treatment.
In the LTlFBR RIA, the following two
assumptions were made regarding the
current Cryptosporidium oocyst
performance to estimate finished water
Cryptosporidium concentrations. First,
based on treatment removal efficiency
data presented in the 1997 IEWSTR,
EPA assumed a national distribution of
physical removal efficiencies with a
mean of 2.0 logs and a standard
deviation oft 0.63 logs. Because the
finished water concentrations of oocysts
represent the baseline against which
improved removal from the LTlFBR is
compared, variations in the log removal
assumption could have considerable
impact on the risk assessment. Second,
to evaluate the impact of the removal
assumptions on the baseline and
resulting improvements, an alternative
mean log removal/inactivation
assumption of 2.5 logs and a standard
deviation of ± 0.63 logs was also used
to calculate finished water
concentrations of Cryptosporidium.
For each of the two baseline
assumptions, EPA 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. As a result, the
RIA considers six scenarios that
encompass the range of endemic health
damages avoided based on the rule.
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, i.e.,
that sites currently operating at the
highest filtered water turbidity 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 VI. 1 indicates estimated annual
benefits associated with implementing
the LTlFBR. The benefits analysis
quantitatively examines endemic health
damages avoided based on the LTlFBR
for each of the six scenarios mentioned
above. For each of these scenarios, EPA
calculated the mean of the distribution
of the number of illnesses avoided. The
10th and 90th percentiles imply that
there is a 10 percent chance that the
estimated value could be as low as the
10th percentile and there is a 10 percent
chance that the estimated value could
be as high as the 90th percentile. EPA's
Office of Water has evaluated drinking
water consumption data from USDA's
1994-1996 Continuing Survey of Food
Intakes by Individuals (CSFII) Study.
EPA's analysis of the CSFII Study
resulted in a daily water ingestion
lognormally distributed with a mean of
1.2 liters per person (EPA, 2000a). The
risk and benefit analysis contained
within the RIA reflects this distribution.
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TABLE VI.1.—NUMBER AND VALUE OF ILLNESSES AVOIDED ANNUALLY FROM TURBIDITY PROVISIONS
[Dollar amounts in billions]
Improved Log-Removal Assumption
Illnesses Avoided with Low Improved Cryptosporidium Removal Assumption:
Mean
10th Percentile
90th Percentile
COI Avoided with Low Improved Cryptosporidium Removal Assumption:
Mean
10th Percentile
90th Percentile
Illnesses Avoided with Mid Improved Cryptosporidium Removal Assumption:
Mean
10th Percentile
90th Percentile
COI Avoided with Mid Improved Cryptosporidium Removal Assumption:
Mean
10th Percentile
90th Percentile
Illnesses Avoided with High Improved Cryptosporidium Removal Assumption:
Mean
10th Percentile
90th Percentile
COI Avoided with High Improved Cryptosporidium Removal Assumption:
Mean
10th Percentile
90th Percentile
Daily Drinking Water Ingestion
and Baseline Cryptosporidium
Log-Removal Assumptions
(Mean = 1 .2 Liters per person)
2.0 log
62,800.0
0.0
152,000.0
$150.3
$0.0
$288.2
77,500.0
0.0
184,000.0
$185.3
$0.0
$350.9
83,600.0
0.0
196,000.0
$199.5
$0.0
$376.7
2.5 log
22,800.0
0.0
43,900.0
$53.9
$0.0
$81.4
27,900.0
.00
52,900.0
$66.2
$0.0
$98.8
30,000.0
0.0
56,500.0
$71.1
$0.0
$105.8
"All values presented are in January 1999 dollars.
According to the RIA performed for
the LTlFBR published today, the rule is
estimated to reduce the mean annual
number of illnesses caused by
Cryptosporidium in water systems with
improved filtration performance by
22,800 to 83,600 cases depending upon
which of the six baseline and improved
Cryptosporidium removal assumptions
was used, and assuming the 1.2 liter
drinking water consumption
distribution. Based on these values, the
mean estimated annual benefits of
reducing the illnesses ranges from $54
million to $200 million per year. The
RIA also indicated that the rule could
result in a mean reduction of 3 to 10
fatalities each year, depending upon the
varied baseline and improved removal
assumptions. Using a mean value of
$5.7 million per statistical life saved,
reducing these fatalities could produce
benefits in the range of $16.0 million to
$60 million.
Combining the value of illnesses and
mortalities avoided, the total benefits
range from $70 million to $260 million
assuming a 1.2 liter drinking water
consumption distribution.
b. Sensitivity Analysis for Recycle
Provisions
Available literature research
demonstrates that increased hydraulic
loading or disruptive hydraulic
currents, such as may be experienced
when plants exceed State-approved
operating capacity or when recycle is
returned directly into the sedimentation
basin, can disrupt filter (Cleasby, 1963;
Glasgow and Wheatley, 1998; McTigue
et al, 1998) and sedimentation (Fulton,
1987; Logsdon, 1987; Cleasby, 1990)
performance. However, the literature
does not quantify the extent to which
performance can be lowered and, more
specifically, does not quantify the log
reduction in Cryptosporidium removal
that may be experienced during direct
recycle events.
In the absence of quantified log
reduction data, the Agency performed a
sensitivity analysis to estimate a range
of potential benefit provided by the
recycle provisions. The analysis
assumes a baseline Cryptosporidium log
removal value of 2.0. The analysis
estimates the effect of recycle by
reducing the average baseline log
removal by a range of values (reduction
ranged from 0.05 to 0.50 log) to account
for the reduction in removal
performance plants may experience if
they exceed State-approved operating
capacity or return recycle to the
sedimentation basin. The installation of
equalization to eliminate exceedence of
State-approved operating capacity or
moving the recycle return location from
the sedimentation basin to prior to the
point of primary coagulant addition will
result in the health benefit. The benefit
estimate is conservative, because it does
not account for the fact that recycle
returns additional oocysts to the plant.
Benefits are estimated by assuming
that the installation of equalization or
moving the recycle return point prior to
the point of primary coagulant addition
will return the plant to the baseline
Cryptosporidium removal of 2.0 log. The
difference between the number of
illnesses that result from the baseline
situation and the reduced performance
is used to calculate the monetary
benefit. The benefit is compared to the
cost of returning recycle prior to the
point of primary coagulant additional
and the cost of installing equalization
for two service populations. Service
populations of 1,900 persons, which
represents a plant serving fewer than
10,000 people, and a service population
of 25,108, which represents a plant
serving greater than 10,000 people, are
used. Results are summarized in Tables
IV.2 and IV.3 below.
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TABLE IV.2.—BENEFIT FOR SERVICE POPULATION OF 1,900
Log removal reduction
0 05
0.50
Benefit" for
population of
1,900
$1,400
30,700
Costa of moving
recycle return
$5,200
5,200
Cost" of install-
ing equalization
$25,200
25,290
"Cost and benefit are annualized with a 7% capital cost over 20 years.
TABLE IV.3.—BENEFIT RANGE FOR SERVICE POPULATION OF 25,108
Log removal reduction
0 05
0.50
] Benefit" for
population of
25,108
$18,700
405,800
Cost" of moving
recycle return
$18,700
18,700
Cost" of install-
ing rqualization
i
$57,200
57,200
»Cost and benefit are annualized with a 7% capital cost over 20 years.
Although literature research does not
quantify the log reduction caused by
specific recycle practices, the results of
the sensitivity analysis show that the
benefit a plant serving 25,108 people
would realize by improving its baseline
performance to 2.0 logs would range
from $18,700 to $405,800. $27,256
Benefits would range from $1,400 to
$30,700 for a plant serving 1,900. This
benefit range supports the Agency's
determination that unqualified benefits
will justify costs. The determination is
discussed in the Benefit Cost
Determination section.
2. Non-Quantified Health and Non-
Health Related Benefits
a. Recycle Provisions
The benefits associated with the filter
backwash provision are unquantified
because of data limitations. Specifically,
there is a lack of treatment performance
data to accurately model the oocysts
removal achieved by individual full-
scale treatment processes and the
impact recycle may have on treatment
unit performance and finished water
quality. Additional data on the ability of
unit processes (sedimentation, DAF,
contact clarification, filtration) to
remove oocysts from source and recycle
flows, the extent to which recycle may
generate hydraulic surge within plants
and lower the performance of individual
treatment processes, data on the
potential for recycle to threaten the
integrity of chemical treatment, and
additional information on the
occurrence of oocysts in recycle streams
are all needed before an impact model
can be calibrated and used as a
predictive tool.
However, available data demonstrate
that oocysts occur in recycle streams,
often at concentrations higher than
found in source water, and returning
recycle streams to the plant will
increase intra-plant oocyst
concentrations. Data also shows that
oocysts frequently occur in the finished
water of treatment plants that are not
operating under stressed conditions.
Engineering literature also shows that
proper coagulation and the maintenance
of balanced hydraulic conditions within
the plant [i.e., not exceeding State
approved sedimentation/clarification
and filtration operating rates) are
important to protect the integrity of the
entire treatment process. Some recycle
practices, such as direct recycle, can
potentially upset coagulation and the
proper hydraulic operation of
sedimentation/clarification and
filtration processes. The benefits of the
recycle provisions are derived from
protecting the coagulation process and
the hydraulic performance of
sedimentation/clarification and
filtration processes. Today's recycle
provisions reduce the risk posed by
recycle and provided additional public
health protection in the following ways:
(1) Returning spent filter backwash,
thickener supernatant, and liquids from
dewatering into, or downstream of, the
point of primary coagulant addition may
disrupt treatment chemistry by
introducing residual coagulant or other
treatment chemicals to the process
stream. The wide variation in plant
influent flow can also result in chemical
over-or under-dosing if chemical dosage
is not adjusted to account for flow
variation. Returning the above flows
prior to the point of primary coagulant
addition will help protect tie integrity
of coagulation and protect the
performance of downstream unit
processes, such as clarification and
filtration, that require proper
coagulation be conducted to maintain
proper performance. This will provide
an additional measure of public health
protection.
(2) The direct recycle of spent filter
backwash without first providing
treatment, equalization, or some form of
hydraulic detention for the flow, may
cause plants to exceed State-approved
operating capacity during recycle
events. This may lead to lower overall
oocyst removal performance due to the
hydraulic overload unit processes (i.e.,
clarification and filtration) experience
and increase finished water oocyst
concentrations. The self assessment
provision in today's rule will help the
States identify direct recycle systems
that may experience this problem so
modifications to recycle practice can be
made to protect public health.
(3) Direct filtration plants do not
employ a sedimentation basin in their
primary treatment process to remove
solids and oocysts; all oocyst removal is
achieved by the filters. If treatment for
the recycle flow is not provided prior to
its return to the plant, all of the oocysts
captured by a filter during a filter run
will be returned to the plant and again
loaded to the filters. This may lead to
ever increasing levels of oocysts being
applied to the filters and could increase
the concentration of oocysts in finished
water. Today's provision for direct
recycle systems will help States identify
those systems that are not obtaining
sufficient oocyst removal from the
recycle flow. Public health protection
will be increased when systems
implement modifications to recycle
practice specified by the State.
The goal of the recycle provisions is
to reduce the potential for oocysts
getting into the finished water and
causing cases of cryptosporidiosis.
Other disinfection resistant pathogens
may also be removed more efficiently
due to implementation of these
provisions.
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b. Issues Associated With Unquantified
Benefits
The monetized benefits from filter
performance improvements are likely
not to fully capture all the benefits of
the turbidity provisions. EPA monetized
the benefits from reductions in
cryptosporidiosis by using cost-of-
illness (COI) estimates. This may
underestimate the actual benefits of
these reductions because COI estimates
do not include pain and suffering. In
general, the COI approach is considered
a lower bound estimate of willingne'ss-
to-pay (WTP) to avoid illnesses. EPA
requests comment on the use of an
appropriate WTP study to calculate the
benefits of this rule.
Several non-health benefits from this
rule were also considered by EPA but
were not monetized. The non-health
benefits of this rule include avoided
outbreak response costs and possibly
reduced uncertainty and averting
behavior costs. By adding the non-
monetized benefits with those that are
monetized, the overall benefits of this
rule would increase beyond the dollar
values reported.
D. Incremental Costs and Benefits
EPA evaluated the incremental or
marginal costs of today's proposed
turbidity option by analyzing various
turbidity limits, 0.3 NTU, 0.2 NTU, and
0.1 NTU. For each turbidity limit, EPA
developed assumptions about which
process changes systems might
implement to meet the turbidity level
and how many systems would adopt
each change. The comparison of total
compliance cost estimates show that
costs are expected to increase
significantly across turbidity limits. The
total cost of a 0.1 NTU limit, $404.6
million, is almost eight times higher
than the cost of the 0.3 NTU limit,
which is $52.2 million. Similarly, the
total cost of the 0.2 NTU limit, $134.1
million, is more than twice as great as
the 0.3 NTU cost.
Analytical limitations in the
estimation of the benefits of LTlFBR
prevent the Agency from quantitatively
describing the incremental benefits of
alternatives. The Agency requests
comment on how to analyze and the
appropriateness of analyzing
incremental benefits and costs for
treatment techniques that address
microbial contaminants.
E. Impacts on Households
The cost impact of LTlFBR at the
household level was also assessed.
Household costs are a way to represent
water system treatment costs as costs to
the system's customers. As expected,
costs per household increase as system
size decreases. Costs to households are
higher for households served by smaller
systems than larger systems for two
reasons. First, smaller systems serve far
fewer households than larger systems,
and consequently, each household must
bear a greater percentage share of capital
and O&M costs. Second, filter backwash
recycling may pose a greater risk
because the flow of water from filter
backwash recycling is a larger portion of
the total water flow in smaller systems.
This greater risk potential in small
systems makes it more likely that some
form of recycle treatment might be
needed.
The average (mean) annual cost for
the turbidity, benchmarking, and
covered finished water provision per
household is $8.66. For almost 86
percent of the 6.6 million households
affected by these provisions, the per-
household costs are $10 per year or less,
and costs of $120 per year (i.e., $10 per
month) or less for approximately 99
percent of the households. Costs
exceeding $500 per household occur
only for the smallest size category, and
the number of affected households
represent about 34 of the smallest
systems. The highest per-household cost
estimate is $2,177. This extreme
estimate, however, is an artifact of the
way the system cost distribution was
generated. It is unlikely that any small
system will incur annual costs of this
magnitude because less costly options
are available.
The average household cost for the
recycle provisions is $1.80 per year for
households that are served by systems
that recycle. The cost per household is
less than $10 per year for almost 99%
of 12.9 million households potentially
affected by the proposed rule. The cost
per household exceeds $120 per year for
less than 1800 households and it
exceeds $500 per year for approximately
100 households. The maximum cost of
$1,238 per year would only be incurred
if a direct filtration system that serves
less than 100 customers installed a
sedimentation basin for backwash
treatment.
There are approximately 1.5 million
households served by small drinking
water systems that may be affected by
the recycling provisions in addition to
the turbidity, benchmarking, and
covered finished water provisions. The
expected aggregate annual cost to these
households can be approximated by the
sum of the expected cost for each
distribution, which is $10.45 per year.
The assumptions and structure of this
analysis tend to overestimate the highest
costs. To face the highest household
costs, a system would have to
implement all, or almost all, of the
treatment activities. These systems,
however, might seek less costly
alternatives, such as connecting into a
larger regional water system.
F. Benefits From the Reduction of Co-
Occurring Contaminants
If a system chooses to install
treatment, it may choose a technology
that would also address other drinking
water contaminants. For example, some
membrane technologies installed to
remove bacteria or viruses can reduce or
eliminate many other drinking water
contaminants including arsenic.
The technologies used to reduce
individual filter turbidities have the
potential to reduce concentrations of
other pollutants as well. Reduction in
turbidity that result from today's
proposed rule are aimed at reducing
Cryptosporidium by physical removal. It
is reasonable to assume that similar
microbial contaminants will also be
reduced as a result of improvements in
turbidity removal. Health risks from
Giardia lamblia and emerging
disinfection resistant pathogens, such as
microsporidia, Toxoplasma, and
Cyclospora, are also likely to be reduced
as a result of improvements in turbidity
removal and recycle practices. The
frequency and extent that LTlFBR
would reduce risk from other
contaminants has not been
quantitatively evaluated because of the
Agency's lack of data on the removal
efficiencies of various technologies for
emerging pathogens and the lack of co-
occurrence data for microbial pathogens
and other contaminants from drink
water systems.
G. Risk Increases From Other
Contaminants
It is unlikely that LTlFBR will result
in any increased risk from other
contaminants. Improvements in plant
turbidity performance will not result in
any increases in risk. In addition, the
benchmarking and profiling provisions
were designed to minimize the potential
reductions in microbial disinfection in
order to lower disinfection byproduct
levels to comply with the Stage 1
Disinfection Byproducts Rule.
Furthermore, the filter backwash
provision does not potentially increase
the risk from other contaminants.
H. Other Factors: Uncertainty in Risk,
Benefits, and Cost Estimates
There is uncertainty in the baseline
number of systems, the risk calculation,
and the cost estimates. Many of these
uncertainties are discussed in more
detail in previous sections of today's
proposal.
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First, the baseline number of systems
is uncertain because of data limitation
problems in SDWIS. For example, some
systems use both ground and surface
water but because of other regulatory
requirements are labeled in SDWIS as
surface water. Therefore, EPA does not
have a reliable estimate of how many of
these mixed systems exist. The SDWIS
data on non-community water systems
does not have a consistent reporting
convention for population served. Some
states may report the population served
over the course of a year, while others
may report the population served on an
average day. Also, SDWIS does not
require states to provide information on
current filtration practices and, in some
cases, it may overestimate the daily
population served. For example, a park
may report the population served yearly
instead of daily. EPA is looking at new
approaches to address these issues and
both are discussed below in request for
comment.
Second, there are several important
sources of uncertainty that enter the
benefits assessment. They include the
following:
• Occurrence of Cryptosporidium
oocysts in source waters
• Baseline occurrence of
Cryptosporidium oocysts in finished
waters
• Reduction of Cryptosporidium
oocysts due to improved treatment,
including filtration and disinfection
• Viability of Cryptosporidium
oocysts after treatment
• Inactivity of Cryptosporidium
• Incidence of infections (including
impact of under reporting)
• Characterization of the risk
Willingness-to-pay to reduce risk and
avoid costs.
• The baseline water system
treatment efficiency for the removal of
Cryptosporidium is uncertain. Turbidity
measurements have been used as a
means of estimating removal treatment
efficiency (i.e. log removal). In addition
to the baseline treatment efficiency
estimates, improvements in treatment
efficiency for Cryptosporidium removal
that result from this rule are uncertain.
The benefit analysis incorporates all
of the uncertainties associated with the
benefits assessment in either the Monte
Carlo simulations or the assumption of
two baselines—2.0 log removal and 2.5
log removal. The results in table VI. 1
show that benefits are more sensitive to
the baseline log removal assumptions
than the range of low to high improved
removal assumptions. Third, some costs
of today's proposed rule are uncertain
because ofthe diverse nature of the
modifications that may be made to
address turbidity limits. Cost analysis
uncertainties are primarily caused by
assumptions made about how many
systems will be affected by various
provisions and how they will likely
respond. Capital and O&M expenditures
account for a majority of total costs. EPA
derived these costs for a "model"
system in each size category using
engineering models, best professional
judgement, and existing cost and
technology documents. Costs for
systems affected by the proposed rule
could be higher or lower, which would
affect total costs. Also, the filter
backwash provision's flexibility for
States to assess plants' need to modify
recycle practices leads to some
uncertainty in the estimates of how
many plants will have to potentially
install some form of recycle equalization
or treatment. These uncertainties could
either under or overestimate the costs of
the rule.
I. Benefit Cost Determination
The Agency has determined that the
benefits ofthe LT1FBR justify the costs.
EPA made this determination for both
the LTl and the FBR portions of the rule
separately as described below.
The Agency has determined that the
benefits of the LTl provisions justify
their costs on a quantitative basis. The
LTl provisions include enhanced
filtration, disinfection benchmarking ,
and other non-recycle related
provisions. The quantified benefits of
$70 million to $259.4 million annually
exceed the costs of $73 million at the
seven percent cost of capital over a
substantial portion of the range of
benefits. In addition, the non-quantified
benefits include avoided outbreak
response costs and possibly reduced
uncertainty and averting behavior costs.
The Agency has determined that the
benefits of the recycle provisions (FBR)
justify their cost on a qualitative basis,
The recycle provisions will reduce the
potential for certain recycle practices to
lower or upset treatment plant
performance during recycle events; the
provisions will therefore help prevent
Cryptosporidium oocysts from entering
finished drinking water supplies and
will increase public health protection.
The Agency strongly believes that
returning Cryptosporidium to the
treatment process in recycle flows, if
performed improperly, can create
additional public health risk. The
Agency holds this belief for three
reasons. First, returning recycle flow
directly to the plant, without
equalization or treatment, can cause
large variations in the influent flow
magnitude and influent water quality. If
chemical dosing is not adjusted to
reflect this, less than optimal chemical
dosing can occur, which may lower the
performance of sedimentation and
filtration. Returning recycle flows prior
to the point of primary coagulant
addition will help diminish the risk of
less than optimal chemical dosing and
diminished sedimentation and filtration
performance. Second, exceeding State-
approved operating capacity, which is
likely to occur if recycle equalization or
treatment is not in place, can
hydraulically overload plants and
diminish the ability of individual unit
processes to remove Cryptosporidium.
Exceeding approved operating capacity
violates fundamental engineering
principles and water treatment
objectives. States set limits on plant
operating capacity and loading rates for
individual unit processes to ensure
treatment plants and individual
treatment processes are operated to :
within their capabilities so that
necessary levels of public health
protection are provided. Third,
returning recycle flows directly into
flocculation or sedimentation basins,
which can generate disruptive hydraulic
currents, may lower the performance of
these units and increase the risk of
Cryptosporidium in finished water
supplies.
The recycle provisions in today's
proposal are designed to address those
recycle practices that are inconsistent
with fundamental engineering and
water treatment principles. The
objective of the provisions is to
eliminate practices that are counter to
common sense, sound engineering
judgement, and that create additional
and preventable risk to public health.
EPA believes the public health
protection benefit provided by the
recycle provisions justifies their cost
because they are based upon sound
engineering principles and are designed
to eliminate recycle practices that are
very likely to create additional public
health risk.
/. Request for Comment
Pursuant to Section 3142(b)(3)(C), the
Agency requests comment on all aspects
of the rule's economic impact analysis.
Specifically, EPA seeks input into the
following two issues.
NTNC and TNC Flow Estimates
As part of the total cost estimates for
LTlFBR, EPA estimated the cost ofthe
rule on NTNC and TNC water systems
by using flow models. However, these ,
flow models were developed to estimate
flows only for CWS and they may not
accurately represent the much smaller
flows generally found in NTNC and
TNC systems. The effect ofthe
overestimate in flow would be to inflate
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the cost of the rule for these systems.
The Agency requests comment on an
alternative flow analysis for NTNC and
TNG water systems described below.
Instead of using the population served
to determine the average flow for use in
the rule's cost calculations, this
alternative approach would re-
categorize NTNC and TNG water
systems based on service type (e.g.,
restaurants or parks). Service type
would be obtained from SDWIS data.
However, service type data is not always
available because it is a voluntary
SDWIS data field. Where unavailable,
the service type would be assigned
based on statistical analysis. Estimates
of service type design flows would be
obtained from engineering design
manuals and best professional
judgement if no design manual
specifications exist.
In addition, each service type category
would also have corresponding rates for
average population served and average
water consumption. These would be
used to determine contaminant
exposure which is used in the benefit
determination. For example, schools
and churches would be two separate
service type categories. They each
would have their own corresponding
average design flow, average population
served (rather than the population as
reported in SDWIS), and average water
consumption rates. These elements
could be used to estimate a rule's
benefits and costs for the average church
and the average school.
Mixed Systems
Current regulations require that all
systems that use any amount of surface
water as.a source be categorized as
surface water systems. This
classification applies even if the
majority of water in a system is from a
ground water source. Therefore, SDWIS
does not provide the Agency with
information to identify how many
mixed systems exist. This information
would help the Agency to better
understand regulatory impacts.
EPA is investigating ways to identify
how many mixed systems exist and how
many mix their ground and surface
water sources at the same entry point or
at separate entry points within the same
distribution systems. For example, a
system may have several plants/entry
points that feed the same distribution
system. One of these entry points may
mix and treat surface water with ground
water prior to its entry into the
distribution system. Another entry point
might use ground water exclusively for
its source while a different entry point
would exclusively use surface water.
However, all three entry points would
supply the same system classified in
SDWIS as surface water.
One method EPA could use to address
this issue would be to analyze CWSS
data then extrapolate this information to
SDWIS to obtain a national estimate of
mixed systems. CWSS data, from
approximately 1,900 systems, details
sources of supply at the level of the
entry point to the distribution system
and further subdivides flow by source
type. The Agency is considering this
national estimate of mixed systems to
regroup surface water systems for
certain impact analyses when
regulations only impact one type of
source. For example, surface water
systems that get more than fifty percent
of their flow from ground water would
be counted as a ground water system in
the regulatory impact analysis for this
rule. The Agency requests comment on
this methodology and its applicability
for use in regulatory impact analysis.
VII. Other Requirements
A. Regulatory Flexibility Act (RFA), as
amended by the Small Business
Regulatory Enforcement Fairness Act of
1996 (SBREFA), 5 USC 601 et seq.
1. Background
The RFA, generally requires an
agency to prepare a regulatory flexibility
analysis of any rule subject to notice
and comment rulemaking requirements
under the Administrative Procedure Act
or any other statute unless the agency
certifies that the rule will not have a
significant economic impact on a
substantial number of small entities.
Small entities include small businesses,
small organizations, and small
governmental jurisdictions.
2. Use of Alternative Definition
The RFA provides default definitions
for each type of small entity. It also
authorizes an agency to use alternative
definitions for each category of small
entity, "which are appropriate to the
activities of the agency" after proposing
the alternative definition(s) in the
Federal Register and taking comment. 5
U.S.C. sees. 601(3)-(5). In addition to
the above, to establish an alternative
small business definition, agencies must
consult with SBA's Chief Counsel for
Advocacy.
EPA is proposing the LTlFBR which
contains provisions which apply to
small PWSs serving fewer than 10,000
persons. This is the cut-off level
specified by Congress in the 1996
Amendments to the Safe Drinking Water
Act for small system flexibility
provisions. Because this definition does
not correspond to the definitions of
"small" for small businesses,
governments, and non-profit
organizations, EPA requested comment
on an alternative definition of "small
entity" in the preamble to the proposed
Consumer Confidence Report (CCR)
regulation (63 FR 7620, February 13,
1998). Comments showed that
stakeholders support the proposed
alternative definition. EPA also
consulted with the SBA Office of
Advocacy on the definition as it relates
to small business analysis. In the
preamble to the final CCR regulation (63
FR 4511, August 19,1998). EPA stated
its intent to establish this alternative
definition for regulatory flexibility
assessments under the RFA for all
drinking water regulations and has thus
used it in this proposed rulemaking.
In accordance with Section 603 of the
RFA, EPA prepared an initial regulatory
flexibility analysis (IRFA) that examines
the impact of the proposed rule on small
entities along with regulatory
alternatives that could reduce that
impact. The IRFA is available for review
in the docket and is summarized below.
3. Initial Regulatory Flexibility Analysis
As part of the 1996 amendments to
the Safe Drinking Water Act (SDWA),
Congress required the U.S.
Environmental Protection Agency (EPA)
to develop a Long Term Stage 1
Enhanced Surface Water Treatment Rule
(LT1ESWTR) under Section
1412(b)(2)(C) which focuses on surface
water drinking water systems that serve
fewer than 10,000 persons. Congress
also required EPA to develop a J
companion Filter Backwash Recycle
Rule (FBRR) under Section 1412(b)(14)
which will require that all surface water
public water systems, regardless of size,
meet new requirements governing the
recycle of filter backwash within the
drinking water treatment process. The
goal of both the LTlESWTR and the
related FBRR is to provide additional
protection from disease-causing
microbial pathogens for community and
non-community public water systems
(PWSs) utilizing surface water.
For purposes of assessing the impacts
of today's rule on small entities, small
entity is defined by systems serving
fewer than 10,000 people. The small
entities directly regulated by this
proposed rule are surface water and
systems using ground water under the
direct influence of surface water
(GWUDI), using filtration and serving
fewer than 10,000 people. We have
determined that the final rule would
result in approximately 2,400 systems
needing capital improvement to meet
the turbidity requirements,
approximately 3,360 systems would
need to significantly change their
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19127
disinfection practices, and
approximately 790 systems would need
to make capital improvements to change
the location of return of their filter
backwash recycle stream. A discussion
of the impacts on small entities is
described in more detail in chapters six
and seven of the Regulatory Impact
Analysis of the LT1FBR (EPA, 1999).
The following recordkeeping and
reporting burdens were projected in the
IRFA:
Turbidity Monitoring and Reporting
Costs
Utility monitoring activities at the
plant level include data collection, data
review, data reporting and monthly
reporting to the State. The labor burden
hours for data collection and review
were calculated under the assumption
that plants are using on-line monitoring,
in the form of a SCADA or other
automated data collection system. The
data collection process requires that a
plant engineer gather and organize
turbidimeter readings from the SCADA
output and enter them into either a
spreadsheet or a log once per 8-hour
shift (three times per day).
After data retrieval, the turbidity data
from each turbidimeter will be reviewed
by a plant engineer once per 8-hour shift
(three times per day) to ensure that the
filters are functioning properly and are
not displaying erratic or exceptional
patterns. A monthly summary data
report would be prepared. This task
involves the review of daily
spreadsheets and the compilation of a
summary report. It is assumed to take
one employee 8 hours per month to
prepare. Recordkeeping is expected to
take 5 hours per month. Recordkeeping
entails organizing daily monitoring
spreadsheets and monthly summary
reports.
Plant-level data will also be reviewed
monthly at the system level to ensure
that each plant in a system is in
compliance with the rule. A system-
level manager or technical worker will
review the daily monitoring
spreadsheets and monthly summary
reports that are generated at the plant
level. This task is estimated to take
about 4 hours per month. Once the
plant-level data have been reviewed, the
system manager or technical worker will
also compile a monthly system
summary report. These reports are
estimated to take 4 hours each month to
prepare.
Disinfection Benchmarking Monitoring
and Reporting Costs
It is assumed that all Subpart H
systems currently collect the daily
inactivation data required to generate a
disinfection profile, in either an
electronic or paper format, and therefore
would not incur additional data
collection expenses due to microbial
profiling. Costs per plant are divided
into costs per plant using paper data,
costs per plant using mainframe data
and costs per plant using PC data. Plants
with paper data were assumed to
represent half of the number of plants
needing benchmarking, while plants
with mainframe and plants with PC data
each represent a quarter.
Filter Backwash Monitoring and
Reporting Costs
The proposed requirements are as
follows: All subpart H systems,
regardless of size, that use conventional
rapid granular filtration, and that return
spent filter backwash, thickener
supernatant, or liquids from dewatering
process to submit a schematic diagram
to the State showing their intended
changes to move the return location
above the point of primary coagulant
addition.
All subpart H systems, regardless of
size, that use conventional rapid
granular filtration and employ 20 or
fewer filters during the highest
production month and that use direct
recycling, to perform a self assessment
of their recycle practice and report the
results to the State.
All subpart H systems, regardless of
system size that use direct filtration
must submit a report of their recycling
practices to the State. The State would
then determine whether changes in
recycling practices were warranted.
EPA believes that the skill level
required for compliance with all of the
above recordkeeping, reporting and
other compliance activities are similar
or equivalent to the skill level required
to pass the first level of operator
certification required by most States.
Relevant Federal Rules
EPA has issued a Stage 1
Disinfectants/Disinfection Byproducts
Rule (DBPR) along with an Interim
Enhanced Surface Water Treatment Rule
(IESWTR) in December 1998, as
required by the Safe Drinking Water Act
Amendments of 1996. EPA proposed
these rules in July 1994. The Stage 1
DBPR includes a THM MCL of 0.080
mg/L (reduced from the existing THM
MCL of 0.10 mg/L established in 1979)
and an MCL of 0.060 mg/L for five
haloacetic acids (another group of
chlorination) as well as MCLs for
chlorite (1.0 mg/L) and bromate (0.010
mg/L) byproducts. The Stage 1 DBPR
also finalized MRDLs for chlorine (4
mg/L as C12), chloramine (4 mg/L as C12)
and chlorine dioxide (0.8 mg/L as CICh).
In addition, the Stage 1 DBPR
includes requirements for enhanced
coagulation to reduce the concentration
of TOG in the water and thereby reduce
DBF formation potential. The IESWTR
was proposed to improve control of
microbial pathogens and to control
potential risk trade-offs related to the
need to meet lower DBF levels under
the Stage 1 DBPR.
None of these regulations duplicate,
overlap or conflict with this proposed
rule.
Significant Alternatives
As a result of consultations during the
SBREFA process, and public meetings
held subsequently, EPA has developed
several alternative options to those
presented in the IRFA, and has selected
preferred alternatives for each of the
turbidity, disinfection benchmarking
and filter backwash recycle provisions.
These alternatives were developed
based on feedback from small system
operators and trade associations and are
designed to protect public health, while
minimizing the burden to small
systems. In summary, the proposed
turbidity requirements are structured to
require recordkeeping once a week as
opposed to daily which was written in
the IRFA; the proposed disinfection
profile requirements are structured to be
taken once per week, as opposed to
daily which was written in the IRFA;
and the filter backwash requirements
have been scaled back significantly from
those included in the IRFA, i.e. a ban on
recycle is no longer being considered,
nor are several treatment techniques
now being considered that were in the
IRFA prior to discussions with
stakeholders. The provisions being
proposed are: systems that recycle will
be required to return recycle flows prior
to the rapid mix unit; direct recycle
systems will need to perform a self
assessment to determine whether
capacity is exceeded during recycle
events, and States will determine
whether recycle practices need to be
changed based on the self-assessment;
and direct filtration systems will need to
report their recycle practices to the
State, which will determine whether
changes to recycle practices are
required,
4. Small Entity Outreach and Small
Business Advocacy Review Panel
As required by section 609(b) of the
RFA, as amended by SBREFA, EPA also
conducted outreach to small entities
and convened a Small Business
Advocacy Review Panel to obtain advice
and recommendations of representatives
of the small entities that potentially
would be subject to the rule's
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requirements. The SBAR Panel
produced two final reports; one for the
LT1 provisions and the other for the
filter backwash provisions. Although
the LTl and filter backwash provisions
have since been combined into the same
rule, the projected economic impact of
the provisions have not significantly
changed, and the relevance of SERs'
comments has not been affected.
The Agency invited 24 SERs to
participate in the SBREFA process, and
16 agreed to participate. The SERs were
provided with background information
on the Safe Drinking Water Act and the
LT1FBR in preparation for a
teleconference on April 28,1998. This
information package included data on
options as well as preliminary unit costs
for treatment enhancements under
consideration. Eight SERs provided
comments on these materials.
On August 25,1998, EPA's Small
Business Advocacy Chair person
convened the Panel under section
609(b) of the Regulatory Flexibility Act
as amended by the Small Business
Regulatory Enforcement Fairness Act
(SBREFA). In addition to its
chairperson, the Panel consisted of the
Director of the Standards and Risk
Management Division of the Office of
Ground Water and Drinking Water
within EPA's Office of Water, the
Administrator of the Office of
Information and Regulatory Affairs
within the Office of Management and
Budget, and the Chief Counsel for
Advocacy of the Small Business
Administration. The SBAR Panels
reports, Final Report of the SBREFA
Small Business Advocacy Review Panel
on EPA's Planned Proposed Rule: Long
Term 1 Enhanced Surface Water
Treatment (EPA, 1998k) and the Final
Report of the SBREFA Small Business
Advocacy Review Panel on EPA's
Planned Proposed Rule: Filter Backwash
Recycling (EPA, 19981), contain the
SERs comments on the components of
the LT1FBR.
The SERs were provided with
additional information on potential
costs related to LTlFBR regulatory
options during teleconferences on
September 22 and 25,1998. Nine SERs
provided additional comments during
the September 22 teleconference, four
SERs provided additional comments
during the September 25 teleconference,
and three SERs provided written
comment on these materials.
In general, the SERs that were
consulted on the LTlFBR were
concerned about the impact of the
proposed rule on small water systems
(because of their small staff and limited
budgets), small systems' ability to
acquire the technical and financial
capability to implement requirements,
and maintaining flexibility to tailor
requirements to the needs and
limitations of small systems. Consistent
with the RFA/SBREFA requirements,
the Panel evaluated the assembled
materials and small-entity comments on
issues related to the elements of the
IRFA. The background information
provided to the SBAR Panel and the
SERs are available for review in the
water docket. A copy of the Panel report
is also included in the docket for this
proposed rule. The Panel's
recommendations to address the SERs
concerns are described next.
a. Number of Small Entities Affected
When the IRFA was prepared, EPA
initially estimated that there were 5,165
small public water systems that use
surface water or GWUDI. A more
detailed discussion of the impact of the
proposed rule and the number of
entities affected is found in Section VI.
None of the commenters questioned the
information provided by EPA on the
number and types of small entities
which may be impacted by the LTlFBR.
This information is based upon the
national Safe Drinking Water
Information System (SDWIS) database,
which contains data on all public •water
systems in the country. The Panel
believed this was a reasonable data
source to characterize the number and
types of systems impacted by the
proposed rule.
b. Recordkeeping and Reporting
The Panel noted that some small
systems are operated by a sole, part time
operator with many duties beyond
operating and maintaining the drinking
•water treatment system and that several
components of the proposed rule may
require significant additional operator
time to implement. These included
disinfection profiling, individual filter
monitoring, and ensuring that short-
term turbidity spikes are corrected
quickly.
One SER stated that assumptions can
be made that small systems will have to
add an additional person to comply
with the monitoring and recordkeeping
portions of the rule. Another SER
commented that the most viable and
economical option would be to use
circuit riders (a trained operator who
travels between plants) to fill staffing
needs, but the LTlFBR would increase
the amount of time that a circuit rider
would be required to spend at each
plant. An additional option
recommended by several SERs to reduce
monitoring burden and cost was to
allow the use of one on-line
turbidimeter to measure several filters.
This would entail less frequent
monitoring of each filter but might still
be adequate to ensure that individual
filter performance is maintained.
The proposed LTlFBR takes into
consideration the recordkeeping and
reporting concerns identified by the
Panel and the SERs. For example,
initially the Agency considered
requiring systems to develop a profile of
individual filter performance. Based on
concerns from the SERs this
requirement was eliminated. In
addition, the Agency initially
considered requiring operators to record
pH, temperature, residual chlorine and
peak hourly flow every day. This
requirement has been scaled back to
once per week to meet difficulties faced
by small system operators. Finally, in
today's proposed rule the Agency is
requesting comment on a modification
to allow one on-line turbidimeter
instead of several to be used at the
smallest size systems (systems serving
fewer than 100 people).
c. Interaction With Other Federal Rules
The Panel noted that the LTlFBR and
Stage 1 DBF rules will affect small
systems virtually simultaneously and
that the Agency should analyze the net
impact of these rules and consider
regulatory options that would minimize
the impact on small systems.
One SER commented that any added
responsibility or workload due to
regulations will have to be absorbed by
him and his staff. He noted that many
systems, including his own, are losing
staff through attrition and are unable to
hire replacements. The SER stated that
he hoped the Panel was aware of the
volume of rules and regulations to
which small systems are currently
subject. As an example, the SER stated
that he had spent a week's time
collecting samples for the mandated
tests of the Lead and Copper rule. He
noted that the sampling had delayed
important maintenance to his system by
over a month.
The Agency considered these
comments when developing the
requirements of today's proposed rule,
and developed the alternatives with the
realization that small systems will be
required to implement several rules in
a short time frame. In today's proposed
rule, the preferred options attempt to
minimize the impact on small systems
by reducing the amount of monitoring
and the amount of operator's time
necessary to collect and analyze data.
For example, under the IESWTR, large
systems are required to monitor
disinfection byproducts for 1 year to
determine whether or not they must
develop a disinfection profile (based on
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19129
daily measurements of operating
conditions). In response to SERs
concerns, the Agency is proposing to
eliminate the requirement for
disinfection byproduct monitoring all
together. Under the proposed
requirements, all systems would
develop a disinfection profile based on
weekly measurements of operating
parameters for 1 year. Overall, this will
save small system operators both time
and money. The proposed rule also
requests comment on several additional
strategies for reducing impacts.
d. Significant Alternatives
During the SBAR panel several
alternatives were discussed with the
Panel and SERs. These alternatives and
the Panel's recommendations are
discussed next.
5. Turbidity Provisions
During the SBAR Panel, the Agency
presented the IESWTR turbidity
provisions as appropriate components
for the LT1FBR. The Panel noted that
one SER commented that it was a fair
assumption that turbidity up to 1 NTU
maximum and 0.3 NTU in 95% of all
monthly samples is a good indicator of
two log removal of Cryptosporidium,
but stressed the need to allow operators
adequate time to respond to
exceedances in automated systems.
They were referring to the fact the small
system operators are often away from
the plant performing other duties, and
cannot respond immediately if the
turbidity levels exceed a predetermined
level. The Panel recommended that EPA
consider this limitation when
developing reporting and recordkeeping
requirements.
The Panel also noted that another SER
agreed that lowered turbidity level is a
good indicator of overall plant •
performance but thought the 0.3 NTU
limit for the 95th percentile reading was
too low in light of studies which appear
to show variability and inaccuracies in
low level turbidity measurements. This
SER referenced specific data suggesting
that current equipment used to measure
turbidity levels below the 0.3 NTU may
nonetheless give readings above 0.3
which would put the system out of
compliance. EPA has evaluated this
issue in the context of the 1997 IESWTR
FACA negotiations and believes that
readings below the 0.3 NTU are reliable.
Moreover, EPA notes that the SERs'
concern was based on raw performance
evaluation data that had not been fully
analyzed.
Finally, the Panel recognized that
several SERs supported individual filter
monitoring, provided there was
flexibility for short duration turbidity
spikes. Other SERs, however, noted that
the assumption that individual filter
monitoring was necessary was
unreasonable. The Panel recommended
that EPA consider the likelihood and
significance of short duration spikes
(i.e., during the first 15-30 minutes of
filter operation) when evaluating the
frequency of individual filter
monitoring and reporting requirements
and the number and types of
exceedances that will trigger
requirements for Comprehensive
Performance Evaluations (CPEs). The
Panel also noted the concern expressed
by several SERs that individual filter
monitoring may not be practical or
feasible in all situations.
The Agency has structured today's
proposed rule with an emphasis on
providing flexibility for small systems.
The individual filter provisions have
been tailored to be easier to understand
and implement and require less data
analysis. For example, the operator can
look at monitoring data once per week
under this rule, as opposed to having to
review turbidity data every day as the
larger systems are required to do. The
proposed rule also requests comment on
several modifications to provide
additional flexibility to small systems.
ii. Disinfection Benchmarking:
Applicability Monitoring Provisions
None of the SERs commented
specifically on the applicability
monitoring provisions which are
designed to identify systems tiiat may
consider cutting back on their
disinfection doses in order to avoid
problems with disinfection byproducts
formation. The Panel noted, however,
that burden on small systems might be
reduced if alternative applicability
monitoring provisions were adopted. In
consideration of the Panel's suggestions,
the Agency first considered limiting the
applicability monitoring, and has now
eliminated this requirement from the
proposal. It is optional, however, for
systems who believe their disinfection
byproduct levels are below 80% of the
MCL—as required under the Stage 1
DBPR.
The Panel noted SER comments that
monitoring and computing Giardia
lamblia inactivation on a daily basis for
a year would place a heavy burden on
operators that may only staff the plant
for a few hours per day. The Panel
therefore recommended that EPA
consider alternative profiling strategies
which ensure adequate public health
protection, but will minimize
monitoring and recordkeeping
requirements for small system operators.
The Agency considered several
alternatives to the profile development
strategies, and decided to propose that
systems perform the necessary
monitoring and record the results once
per week, instead of every day as the
larger systems are required to do. This
will significantly reduce burden and
costs for small systems.
iii. Recycling Provisions
During the SBAR Panel, the Agency
proposed several alternatives for
consideration in the LT1FBR including
a ban on recycle, a requirement to return
recycle flow to the head of the plant,
recycle flow equalization, and recycle
flow treatment. The Panel noted the
concern of the SERs regarding a ban on
the recycle of filter backwash water.
These concerns included the expense of
filter backwash disposal and the
economic and operational concerns of
western and southwestern drinking
water systems which depend on
recycled flow to maintain adequate
supply. The Panel strongly
recommended that EPA explore
alternatives to an outright ban on the
recycle of filter backwash and other
recycle flows.
The Panel noted that SERs supported
a requirement that all recycled water be
reintroduced at the head of the plant.
This was considered an element of
sound engineering practice. The Panel
recommended that EPA consider
including such a requirement in the
proposed rule, and investigate whether
there are small systems for which such
a requirement would present a
significant financial and operational
burden.
The Panel noted that SERs agreed
with the appropriateness of flow
equalization for filter backwash. The
Panel supported the concept of flow
equalization as a means to minimize
hydraulic surges that may be caused by
recycle and the reintroduction of a large
number of Cryptosporidium oocysts or
other pathogenic contaminants to the
plant in a brief period of time. The
Panel noted that there are various ways
of achieving flow equalization and
suggested that specific requirements
remain flexible.
The Panel noted the concerns of SERs
regarding installation of treatment,
solely for the purpose of treating filter
backwash water and/or recycle streams
may be costly and potentially
prohibitive for small systems. The
Agency addressed this concern by
allowing the States to determine
whether recycle flow equalization or
treatment is necessary based on the
results of the self assessment prepared
by the S3fstem rather than requiring
universal flow equalization or
treatment. This will allow site-specific
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factors to be considered and help
minimize cost and burden.
e. Other Comments
The Panel also noted the concern of
several SERs that flexibility be provided
in the compliance schedule of the rule.
SERs noted the technical and financial
limitations that some small systems will
have to address, the significant learning
curve for operators with limited
experience, and the need to continue
providing uninterrupted service as
reasons why additional compliance time
may be needed for small systems. The
panel encouraged EPA to keep these
limitations in mind in developing the
proposed rule and provide as much
compliance flexibility to small systems
as is allowable under the SDWA. We
invite comments on all aspects of the
proposal and its impacts on small
entities.
The Agency structured the timing of
the LT1ESWTR provisions specifically
to follow the promulgation of the
IESWTR. Since the IESWTR served as a
template for the establishment of the
LTlESWTR provisions, the Agency
decided that small systems would have
an advantage by giving them an
opportunity to see what was in the rule,
and how it was implemented by larger
systems.
Under SDWA, systems have 3 years to
comply with the requirements of the
final rule. If capital improvements are
necessary for a particular PWS, a State
may allow the system up to an
additional 2 years to comply with the
regulation. The Agency is developing
guidance manuals to assist the
compliance efforts of small entities.
B. Paperwork Reduction Act
The information collection
requirements in this proposed rule have
been submitted for approval to the
Office of Management and Budget
(OMB) under the Paperwork Reduction
Act, 44 U.S.C. 3501 et seq. An
Information Collection Request (ICR)
document has been prepared by EPA
(ICR No. 1928.01) and a copy may be
obtained from Sandy Farmer by mail at
OP Regulatory Information Division;
U.S. Environmental Protection Agency
(2137); 401 M St., S.W.; Washington, DC
20460, by email at
farmer.sandy@epamail.epa.gov, or by
calling (202) 260-2740. A copy may also
be downloaded off the Internet at http:/
lwww.epa.gov/icr. For technical
information about the collection contact
Jini Mohanty by calling (202) 260-6415.
The information collected as a result
of this rule will allow the States and
EPA to determine appropriate
requirements for specific systems, in
some cases, arid to evaluate compliance
with the rule. For the first three years
after the effective date (six years after
promulgation) of the LT1FBR, the major
information requirements are (1)
monitor filter performance and submit
any exceedances of turbidity
requirements (/.e. exceptions reports) to
the State; (2) develop a 1 month recycle
monitoring plan and submit both plan
and results to the State; (3) submit flow
monitoring plan and results to the State;
and (4) report data on current recycle
treatment (self assessment) to the State.
The information collection requirements
in Part 141, for systems, and Part 142,
for States are mandatory. The
information collected is not
confidential.
Burden means the total time, effort, or
financial resources expended by persons
to generate, maintain, retain, or disclose
or provide information to or for a
Federal Agency. This includes the time
needed to review instructions; develop,
acquire, install, and utilize technology
and systems for the purposes of
collecting, validating, and verifying
information, processing and
maintaining information, and disclosing
and providing information; adjust the
existing ways to comply with any
previously applicable instructions and
requirements; train personnel to be able
to respond to a collection of
information; search data sources;
complete and review the collection of
information; and transmit or otherwise
disclose the information.
The preliminary estimate of aggregate
annual average burden hours for
LTlFBR is 311,486. Annual average
aggregate cost estimate is $10,826,919
for labor, $2,713,815 for capital, and
$1,898,595 for operation and
maintenance including lab costs which
is a purchase of service. The burden
hours per response is 18.9. The
frequency of response (average
responses per respondent) is 2.7
annually. The estimated number of
likely respondents is 6,019 (the product
of burden hours per response,
frequency, and respondents does not
total the annual average burden hours
due to rounding). Most of the regulatory
provisions discussed in this notice
entail new reporting and recordkeeping
requirements for States, Tribes, and
members of the regulated public. An
Agency may not conduct or sponsor,
and a person is not required to respond
to a collection of information unless it
displays a currently valid OMB control
number. The OMB control numbers for
EPA's regulations are listed in 40 CFR
Part 9 and 48 CFR Chapter 15.
Comments are requested on the
Agency's need for this information, the
accuracy of the provided burden
estimates, and any suggested methods
for minimizing respondent burden,
including through the use of automated
collection techniques. Send comments
on the ICR to the Director, OP
Regulatory Information Division; U.S.
Environmental Protection Agency
(2137); 401 M St., S.W.; Washington, DC
20460; and to the Office of Information
and Regulatory Affairs, Office of
Management and Budget, 725 17th St.,
N.W., Washington, DC 20503, marked
"Attention: Desk Officer for EPA."
Include the ICR number in any
correspondence. Since OMB is required
to make a decision concerning the ICR
between 30 and 60 days after April 10,
2000, a comment to OMB is best assured
of having its full effect if OMB receives
it by May 10, 2000. The final rule will
respond to any OMB or public
comments on the information collection
requirements contained in this proposal.
C. Unfunded Mandates Reform Act
1. Summary of UMRA requirements
Title II of the Unfunded Mandates
Reform Act of 1995 (UMRA), Public
Law 104-4, establishes requirements for
Federal agencies to assess the effects of
their regulatory actions on State, local,
and tribal governments and the private
sector. Under UMRA section 202, EPA
generally must prepare a written
statement, including a cost-benefit
analysis, for proposed and final rules
with "Federal mandates" that may
result in expenditures by State, local,
and tribal governments, in the aggregate,
or to the private sector, of $100 million
or more in any one year. Before
promulgating an EPA rule, for which a
written statement is needed, section 205
of the UMRA generally requires EPA to
identify and consider a reasonable
number of regulatory alternatives and
adopt the least costly, most cost-
effective or least burdensome alternative
that achieves the objectives of the rule.
The provisions of section 205 do not
apply when they are inconsistent with
applicable law. Moreover, section 205
allows EPA to adopt an alternative other
than the least costly, most cost effective
or least burdensome alternative if the
Administrator publishes with the final
rule an explanation why that alternative
was not adopted.
Before EPA establishes any regulatory
requirements that may significantly or
uniquely affect small governments,
including tribal governments, it must
have developed, under section 203 of
the UMRA, a small government agency
plan. The plan must provide for
notification to potentially affected small
governments, enabling officials of
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19131
affected small governments to have
meaningful and timely input in the
development of EPA regulatory
proposals with significant Federal
intergovernmental mandates and
informing, educating, and advising
small governments on compliance with
the regulatory requirements.
2. Written Statement for Rules With
Federal Mandates of $100 Million or
More
EPA has determined that this rule
does not contain a Federal mandate that
may result in expenditures of $100
million or more for the State, local and
Tribal governments, in the aggregate, or
the private sector in any one year. Thus
today's rule is not subject to the
requirements of sections 202 and 205 of
the UMRA. Nevertheless, since the
estimate of annual impact is close to
SlOO million under certain assumptions
EPA has prepared a written statement,
which is summarized below, even
though one is not required. A more
detailed description of this analysis is
presented in EPA's Regulatory Impact
Analysis of the LTlFBR (EPA, 1999h)
which is available for public review in
the Office of Water docket under docket
number W-99-10. The document is
available for inspection from 9 a.m. to
4 p.m., Monday through Friday,
excluding legal holidays. The docket is
located in room EB 57, USEPA
Headquarters, 401 M St. SW,
Washington, D.C. 20460. For access to
docket materials, please call (202) 260-
3027 to schedule an appointment.
a. Authorizing Legislation
Today's rule is proposed pursuant to
Section 1412 (b)(2)(C) and 1412(b)(14) of
the SDWA. Section 1412 (b)(2)(C)
directs EPA to establish a series of
regulations including an interim and
final enhanced surface water treatment
rule. Section 1412(b)(14) directs EPA to
promulgate a regulation to govern the
recycling of filter backwash water. EPA
intends to finalize the LTlFBR in the
year 2000 to allow systems to consider
the dual impact of this rule and the
Stage 1 DBF rule on their capital
investment decisions.
b. Cost Benefit Analysis
Section VI of this preamble discusses
the cost and benefits associated with the
LTlFBR. Also, the EPA's Regulatory
Impact Analysis of the LTlFBR (EPA,
1999h) contains a detailed cost benefit
analysis. Today's proposal is expected
to have a total annualized cost of
approximately $ 97.5 million using a 7
percent discount rate. At a 3 percent
discount rate the annualized costs drop
to $87.6 million. The national cost
estimate includes cost for all of the
rule's major provisions including
turbidity monitoring, disinfection
benchmarking monitoring, disinfection
profiling, covered finished storage, and
recycling. The majority of the costs for
this rule will be incurred by the public
sector. A more detailed discussion of
these costs is located in Section VI of
this preamble.
In addition, the regulatory impact
analysis includes both monetized
benefits and descriptions of
unquantified benefits for improvements
to public health and safety the rule will
achieve. Because of scientific
uncertainty regarding LTlFBR's
exposure and risk assessment, the
Agency has used Monte Carlo methods
and sensitivity analysis to assess the
quantified benefits of today's rule. The
monetary analysis was based upon
quantification of the number of
cryptosporidiosis illnesses avoided due
to improved particulate removal that
results from the turbidity provisions.
The Agency was not able to monetize
the benefits from the other rule
provisions such as disinfection
benchmarking and covered finished
storage. The monetized annual benefits
of today's rule range from $70.1 million
to $259.4 million depending on the
^baseline and removal assumptions.
Better management of recycle streams
required by the proposal also result in
nonquantifiable health risk reductions
from disinfection resistant pathogens.
The rule may also decrease illness
caused by Giardia and other emerging
disinfection resistant pathogens, further
increasing the benefits.
Several non-health benefits from this
rule were also identified by EPA but
were not monetized. The non-health
benefits of this rule include outbreak
response costs avoided, and possibly
reduced uncertainty and averting
behavior costs. By adding the non-
monetized benefits with those that are
monetized, the overall benefits of this
rule increase beyond the dollar values
reported.
Various Federal programs exist to
provide financial assistance to State,
local, and Tribal governments in
complying with this rule. The Federal
government provides funding to States
that have primary enforcement
responsibility for their drinking water
programs through the Public Water
Systems Supervision Grants program.
Additional funding is available from
other programs administered either by
EPA, or other Federal Agencies. These
include EPA's Drinking Water State
Revolving Fund (DWSRF), U.S.
Department of Agriculture's Rural
Utilities' Loan and Grant Program, and
Housing and Urban Development's
Community Development Block Grant
Program.
For example, SDWA authorizes the
Administrator of the EPA to award
capitalization grants to States, which in
turn can provide low cost loans and
other types of assistance to eligible
public water systems. The DWSRF helps
public water systems finance the cost of
infrastructure necessary to achieve or
maintain compliance with SDWA
requirements. Each State has
considerable flexibility to design its
program and to direct funding toward
the most pressing compliance and
public health protection needs. States
may also, on a matching basis, use up
to ten percent of their DWSRF
allotments each fiscal year to run the
State drinking water program.
Furthermore, a State can use the
financial resources of the DWSRF to
assist small systems. In fact, a minimum
of 15% of a State's DWSRF grant must ,
be used to provide infrastructure loans
to small systems. Two percent of the
State's grant may be used to provide
technical assistance to small systems.
For small systems that are .
disadvantaged, up to 30% of a State's
DWSRF may be used for increased loan
subsidies. Under the DWSRF, Tribes ;
have a separate set-aside which they can
use. In addition to the DWSRF, money
is available from the Department of
Agriculture's Rural Utility Service
(RUS) and Housing and Urban
Development's Community Block Grant
(CDBG) program. RUS provided-loans,
guaranteed loans, and grants to improve,
repair, or construct water supply and
distribution systems in rural areas and
towns up to 10,000 people. In fiscal year
1997, the RUS had over $1.3 billion in
available funds. Also, three sources of
funding exist under the CDBG program
to finance building and improvements ,
of public faculties such as water
systems. The three sources of funding
include: (1) Direct grants to
communities with populations over
200,000; (2) direct grants to States,
which they in turn award to smaller
communities, rural areas, and colonias
in Arizona, California, New Mexico, and
Texas; and (3) direct grants to US.
Territories and Trusts. The CDBG
budget for fiscal year 1997 totaled over
$4 billion dollars.
c. Estimates of Future Compliance Costs;
and Disproportionate Budgetary Effects
To meet the UMRA requirement in
section 202, EPA analyzed future
compliance costs and possible
disproportionate budgetary effects. The
Agency believes that the cost estimates,
indicated previously and discussed in
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more detail in Section VI of this
preamble, accurately characterize future
compliance costs.
In analyzing the disproportionate
impacts, EPA considered four measures:
(l) The impacts of small versus large
systems and the impacts within the five
small system size categories;
(2) The costs to public versus private
water systems;
(3) The costs to households, and;
(4) The distribution of costs across
States.
First, small systems will experience a
greater impact than large systems under
LT1FBR because large systems are
subject only to the recycle provisions.
The Interim Enhanced Surface Water
Treatment Rule (IESWTR) promulgated
turbidity, benchmarking, and covered
finished storage provisions for large
systems in December, 1998. However,
small systems have realized cost savings
over time due to their exclusion from
the IESWTR. Also, some provisions in
the LT1FBR have been modified so they
would not be as burdensome for small
systems. Further information on these
changes can be found in section
VII.A.3.of this proposal.
The second measure of impact is the
relative total cost to privately owned
water systems compared to the incurred
by publicly owned water systems. A
majority of the systems are publicly
owned (60 percent of the total]. As a
result, publicly owned systems will
incur a larger share of the total costs of
the rule.
The third measure, household costs,
is described in further detail in VLB of
this preamble. The fourth measure,
distribution of costs across States, is
described in greater detail in the RIA for
today's proposed rule (EPA, 1999h).
There is nothing to suggest that costs to
individual systems would vary
significantly from State to State, but as
expected, the States with the greatest
number of systems experience the
greatest costs.
d. Macro-Economic Effects
As required under UMRA Section
202, EPA is required to estimate the
potential macro-economic effects of the
regulation. These types of effects
include those on productivity, economic
growth, full employment, creation of
productive jobs, and international
competitiveness. Macro-economic
effects tend to be measurable in
nationwide econometric models only if
the economic impact of the regulation
reaches 0.25 percent to 0.5 percent of
Gross Domestic Product (GDP). In 1998,
real GDP was $7,552 billion. This
proposal would have to cost at least $18
billion to have a measurable effect. A
regulation of less cost is unlikely to
have any measurable effect unless it is
highly focused on a particular
geographic region or economic sector.
The macro-economic effects on the
national economy from LTlFBR should
not have a measurable effect because the
total annual cost of the preferred option
is approximately $ 97.5 million per year
(at a seven percent discount rate). The
costs are not expected to be highly
focused on a particular geographic
region or sector.
e. Summary of EPA's Consultation with
State, Local, and Tribal Governments
and Their Concerns
Consistent with the intergovernmental
consultation provisions of section 204 of
UMRA EPA has already initiated
consultation with the governmental
entities affected by this rule.
EPA began outreach efforts to develop
the LTlFBR in the summer of 1998.
Two public stakeholder meetings,
which were announced in the Federal
Register, were held on July 22-23, 1998,
in Lakewood, Colorado, and on March
3-4,1999, in Dallas, Texas. In addition
to these meetings, EPA has held several
formal and informal meetings with
stakeholders including the Association
of State Drinking Water Administrators.
A summary of each meeting and
attendees is available in the public
docket for this rule. EPA also convened
a Small Business Advocacy Review
(SBAR) Panel in accordance with the
Regulatory Flexibility Act (RFA), as
amended by the Small Business
Regulatory Enforcement Fairness Act
(SBREFA) to address small entity
concerns including those of small local
governments. The SBAR Panel allows
small regulated entities to provide input
to EPA early in the regulatory
development process. In early June,
1999, EPA mailed an informal draft of
the LTlFBR preamble to the
approximately 100 stakeholders who
attended one of the public stakeholder
meetings. Members of trade associations
and the SBREFA Panel also received the
draft preamble. EPA received valuable
comments and stakeholder input from
15 State representatives, trade
associations, environmental interest
groups, and individual stakeholders.
The majority of concerns dealt with
reducing burden on small systems and
maintaining flexibility. After receipt of
comments, EPA made every effort to
make modifications to address these
concerns.
To inform and involve Tribal
governments in the rulemaking process,
EPA presented the LTlFBR at three
venues: the 16th Annual Consumer
Conference of the National Indian
Health Board, the annual conference of
the National Tribal Environmental
Council, and the OGWDW/Inter Tribal
Council of Arizona, Inc. tribal
consultation meeting. Over 900
attendees representing tribes from
across the country attended the National
Indian Health Board's Consumer
Conference and over 100 tribes were
represented at the annual conference of
the National Tribal Environmental
Council. At both conferences, an
OGWDW representative conducted two
workshops on EPA's drinking water
program and upcoming regulations,
including the LTlFBR.
At the OGWDW/Inter Tribal Council
of Arizona meeting, representatives
from 15 tribes participated. The
presentation materials and meeting
summary were sent to over 500 tribes
and tribal organizations. Additionally,
EPA contacted each of our 12 Native
American Drinking Water State
Revolving Fund Advisors to invite
them, and representatives of their
organizations to the stakeholder
meetings described previously. A list of
tribal representatives contacted can be
found in the docket for this rule.
The primary concern expressed by
State, local and Tribal governments is
the difficulty the smallest systems will
encounter in adequately staffing
drinking water treatment facilities to
perform the monitoring and reporting
associated with the new requirements.
Today's proposal attempts to minimize
the monitoring and reporting burden to
the greatest extent feasible and still
accomplish the rule's objective of
protecting public health. The Agency
believes the monitoring and reporting
requirements are necessary to ensure
consumers served by small systems
receive the same level of public health
protection as consumers served by large
systems. Summaries of the meetings
have been included in the public docket
for this rulemaking.
f. Regulatory Alternatives Considered
As required under Section 205 of the
UMRA, EPA considered several
regulatory alternatives for individual
filter monitoring and disinfection
benchmarking, as well as several
alternative strategies for addressing
recycle practices. A detailed discussion
of these alternatives can be found in
Section IV and also in the RIA for
today's proposed rule (EPA, 1999h).
Today's proposal also seeks comment
on several regulatory alternatives that
EPA will consider for the final rule.
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g. Selection of the Least Costly, Most-
Cost Effective or Least Burdensome
Alternative That Achieves the
Objectives of the Rule
As discussed previously, EPA has
considered and requested comment on
various regulatory options that would
reduce Cryptosporidium occurrence in
the finished water of surface water
systems. The Agency believes that the
preferred option for turbidity
performance, disinfection
benchmarking, and recycle management
are the most cost effective combination
of options to achieve the rule's
objective; the reduction of illness and
death from Cryptosporidium occurrence
in the finished water of PWSs using
surface water. The Agency will carefully
review comments on the proposal and
assess suggested changes to the
requirements.
3. Impacts on Small Governments
In developing this proposal, EPA
consulted with small governments to
address impacts of regulatory
requirements in the rule that might
significantly or uniquely affect small
governments. As discussed previously, a
variety of stakeholders, including small
governments, were provided the
opportunity for timely and meaningful
participation in the regulatory
development process through the
SBREFA panel, public stakeholder and
Tribal meetings. EPA used these
processes to notify potentially affected
small governments of regulatory
requirements being considered and
provided officials of affected small
governments with an opportunity to
have meaningful and timely input to the
regulatory development process.
In addition, EPA will educate, inform,
and advise small systems, including
those run by small governments, about
LTlFBR requirements. One of the most
important components of this outreach
effort will be the Small Entity
Compliance Guide, required by the
Small Business Regulatory Enforcement
Fairness Act of 1996. This plain-English
guide will explain what actions a small
entity must take to comply with the
rule. Also, the Agency is developing fact
sheets that concisely describe various
aspects and requirements of the LTlFBR
and detailed guidance manuals to assist
the compliance effort of PWSs and small
government entities.
D. National Technology Transfer and
Advancement Act
Section 12(d) of the National
Technology Transfer and Advancement
Act of 1995 (NTAA), Public Law No.
104-113, section 12(d) (15 U.S.C. 272
note), directs EPA 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) that are developed or
adopted by voluntary consensus
standards bodies. The NTAA directs
EPA to provide Congress, through the
Office of Management and Budget,
explanations when the Agency decides
not to use available and applicable
voluntary consensus standards.
Today's rule requires the use of
previously approved technical
standards for the measurement of
turbidity. In previous rulemakings, EPA
approved three methods for measuring
turbidity in drinking water. These can
be found in 40 CFR, Part 141.74 (a).
Turbidity is a method-defined
parameter and therefore modifications
to any of the three approved methods
requires prior EPA approval. One of the
approved methods was published by the
Standard Methods Committee of
American Public Health Association,
the American Water Works Association,
and the Water Environment Federation,
the latter being a voluntary consensus
standard body. That method, Method
2130B (APHA, 1995), is published in
Standard Methods for the Examination
of Water and Wastewater (19th ed.).
Standard Methods is a widely used
reference which has been peer-reviewed
by the scientific community. In addition
to this voluntary consensus standard,
EPA approved two additional methods
for the measurement of turbidity. One is
the Great Lakes Instrument Method 2,
which can be used as an alternate test
procedure for the measurement of
turbidity (Great Lakes Instruments,
1992). Second, the Agency approved
revised EPA Method 180.1 for turbidity
measurement in August 1993 in
Methods for the Determination of
Inorganic Substances in Environmental
Samples (EPA-600/R-93-100) (EPA,
1993).
In 1994, EPA reviewed and rejected
an additional technical standard, a
voluntary consensus standard, for the
measurement of turbidity, die ISO 7027
standard, an analytical method which
measures turbidity at a higher
wavelength than the approved test
measurement standards. ISO 7027
measures turbidity using either 90°
scattered or transmitted light depending
on the turbidity concentration
evaluated. Although instruments
conforming to ISO 7027 specifications
are similar to the GLI instrument, only
the GLI instrument uses pulsed,
multiple detectors to simultaneously
read both 90° scattered and transmitted
light. EPA has no data upon which to
evaluate whether the separate 90°
scattered or transmitted light
measurement evaluations, according to
the ISO 7027 method, would produce
results that are equivalent to results
produced using GLI Method 2, Standard
Method 2130B (APHA, 1995), or EPA
Method 180.1 (EPA, 1993).
Today's proposed rule also requires
continuous individual filter monitoring
for turbidity and requires PWSs to
calibrate the individual turbidimeter
according to the turbidimeter
manufacturer's instructions. These
calibration instructions may constitute
technical standards as that term is
defined in the NTTAA. EPA has looked
for voluntary consensus standards with
regard to calibration of turbidimeters.
The American Society for Testing and
Materials (ASTM) is developing such
voluntary consensus standards,
however, there do not appear to be any
voluntary consensus standards available
at this time. EPA welcomes comments
on this aspect of the proposed
rulemaking and, specifically invites the
public to identify potentially applicable
voluntary consensus standards and to
explain why such standards should be
used in this regulation.
EPA plans to implement in the future
a performance-based measurement
system (PBMS) that would allow the
option of using either performance
criteria or reference methods in its
drinking water regulatory programs. The
Agency is currently determining the
specific steps necessary to implement
PBMS in its programs and preparing an
implementation plan. Final decisions
have not yet been made concerning the
implementation of PBMS in water
programs. However, EPA is currently
evaluating what relevant performance
characteristics should be specified for
monitoring methods used in the water
programs under a PBMS approach to
ensure adequate data quality. EPA
would then specify performance
requirements in its regulations to ensure
that any method used for determination
of a regulated analyte is at least
equivalent to the performance achieved
by other currently approved methods.
Once EPA has made its final
determinations regarding
implementation of PBMS in programs
under the Safe Drinking Water Act, EPA
would incorporate specific provisions of
PBMS into its regulations, which may
include specification of the performance
characteristics for measurement of
regulated contaminants in the drinking
water program regulations.
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E. Executive Order 12866: Regulatory
Planning and Review
Under Executive Order 12866, (58 FR
51735 (October 4, 1993) the Agency
must determine whether the regulatory
action is "significant" and therefore
subject to OMB review and the
requirements of the Executive Order.
The Order defines "significant
regulatory action" as one that is likely
to result in a rule that may:
1. Have an annual effect on the
economy of $100 million or more or
adversely affect in a material way the
economy, a sector of the economy,
productivity, competition, jobs, the
environment, public health or safety, or
State, local, tribal governments or
communities;
2. Create a serious inconsistency or
otherwise interfere with an action taken
or planned by another agency;
3. Materially alter the budgetary
impact of entitlement, grants, user fees,
or loan programs or the rights and
obligations of recipients thereof, or;
4. Raise novel legal or policy issues
arising out of legal mandates, the
President's priorities, or the principles
set forth in the Executive Order.
Pursuant to the terms of Executive
Order 12866, it has been determined
that this rule is a "significant regulatory
action." As such, this action was
submitted to OMB for review. Changes
made in response to OMB suggestions or
recommendations will be documented
in the public record.
F. Executive Order 12898:
Environmental Justice
Executive Order 12898 establishes a
Federal policy for incorporating
environmental justice into Federal
agency missions by directing agencies to
identify and address disproportionately
high and adverse human health or
environmental effects of its programs,
policies, and activities on minority and
low-income populations. The Agency
has considered environmental justice
related issues concerning the potential
impacts of this action and consulted
with minority and low-income
stakeholders.
This preamble has discussed many
times how the IESWTR served as a
template for the development of the
LTlFBR. As such, the Agency also built
on the efforts conducted during the
lESWTRs development to comply with
E.O. 12898. On March 12,1998, the
Agency held a stakeholder meeting to
address various components of pending
drinking water regulations and how
they may impact sensitive sub-
populations, minority populations, and
low-income populations. Topics
discussed included treatment
techniques, costs and benefits, data
quality, health effects, and the
regulatory process. Participants
included national, State, tribal,
municipal, and individual stakeholders.
EPA conducted the meetings by video
conference call between eleven cities.
This meeting was a continuation of
stakeholder meetings that started in
1995 to obtain input on the Agency's
Drinking Water Programs. The major
objectives for the March 12,1998
meeting were:
(1) Solicit ideas from stakeholders on
known issues concerning current
drinking water regulatory efforts;
(2) Identify key issues of concern to
stakeholders, and;
(3) Receive suggestions from
stakeholders concerning ways to
increase representation of communities
in OGWDW regulatory efforts.
In addition, EPA developed a plain-
English guide specifically for this
meeting to assist stakeholders in
understanding the multiple and
sometimes complex issues surrounding
drinking water regulation.
The LTlFBR applies to community
water systems, non-transient non-
community water systems, and transient
non-community water systems that use
surface water or ground water under the
direct influence (GWUDI) as their
source water for PWSs serving less than
10,000 people. The recycle provisions
apply to all conventional and direct
surface water or GWUDI systems
regardless of size.
EPA believes this rule will provide
equal health protection for all minority
and low-income populations served by
systems regulated under this rule from
exposure to microbial contamination.
These requirements will also be
consistent with the protection already
afforded to people being served by
systems with larger population bases.
G. Executive Order 13045Protection of
Children from Environmental Health
Risks and Safety Risks
Executive Order 13045: "Protection of
Children from Environmental Health
Risks and Safety Risks" (62 FR 19885,
April 23,1997) applies to any rule that:
1) is determined to be economically
significant as defined under E.O. 12866,
and; 2) concerns an environmental
health or safety risk that EPA has reason
to believe may have a disproportionate
effect on children. If the regulatory
action meets both criteria, the Agency
must evaluate the environmental health
or safety effects of the planned rule on
children and explain why the planned
regulation is preferable to other
potentially effective and reasonably
feasible alternatives considered by the
Agency.
While this proposed rule is not
subject to the Executive Order because
it is not economically significant as
defined by E.O. 12866, we nonetheless
have reason to believe that the
environmental health or safety risk
addressed by this action may have a
disproportionate effect on children.
Accordingly, EPA evaluated available
data on the health effect of
Cryptosporidium on children. The
results of this evaluation are contained
in Section II.B of this preamble and in
the LTlFBR RIA (EPA, 1999h). A copy
of the RIA and supporting documents is
available for public review in the Office
of Water docket at 401 M St. SW,
Washington, D.C.
The risk of illness and death due to
cryptosporidiosis depends on several
factors, including the age, nutrition,
exposure, and the immune status of the
individual. Information on mortality
from diarrhea shows the greatest risk of
mortality occurring among the very
young and elderly (Gerba et al., 1996).
Specifically, young children are a
vulnerable population subject to
infectious diarrhea caused by
Cryptosporidium (CDC 1994).
Cryptosporidiosis is prevalent
worldwide, and its occurrence is higher
in children than in adults (Payer and
Ungar, 1986).
Cryptosporidiosis appears to be more
prevalent in populations that may not
have established immunity against the
disease and may be in greater contact
with environmentally contaminated
surfaces, such as infants (DuPont, et al.,
1995). Once a child is infected it may
spread the disease to other children or
family members. Evidence of such
secondary transmission of
cryptosporidiosis from children to
household and other close contacts has
been found in many outbreak
investigations (Casemore, 1990; Cordell
et al., 1997; Frost et al., 1997). Chapell
et al., 1999, found that prior exposure to
Cryptosporidium through the ingestion
of a low oocyst dose provides protection
from infection and illness. However, it
is not known whether this immunity is
life-long or temporary. Data also
indicate that either mothers confer short
term immunity to their children or that
babies have reduced exposure to
Cryptosporidium, resulting in a
decreased incidence of infection during
the first year of life. For example, in a
survey of over 30,000 stool sample
analyses from different UK patients, the
1—5 year age group suffered a much
higher infection rate than individuals
less than one year of age. For children
under one year of age, those older than
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six months of age showed a higher rate
of infection than individuals aged fewer
than six months (Casemore, 1990).
EPA has not been able to quantify the
differential health effects for children as
a result of Cryptosporidium-
contamSnated drinking water. However,
the result of the LTlFBR will be a
reduction in the risk of illness for the
entire population, including children.
Furthermore, the available anecdotal
evidence indicates that children may be
more vulnerable to cryptosporidiosis
than the rest of the population. The
LTlFBR would, therefore, result in
greater risk reduction for children than
for trie general population.
The public is invited to submit or
identify peer-reviewed studies and data,
of which EPA may not be aware, that
assessed results of early life exposure to
Cryptosporidium.
H. Consultations ivith the Science
Advisory Board, National Drinking
Water Advisory Council, and the
Secretary of Health and Human Services
In accordance with section 1412 (d)
and (e) of the SDWA, the Agency will
consult with the National Drinking
Water Advisory Council (NDWAC) and
the Secretary of Health and Human
Services and request comment from the
Science Advisory Board on the
proposed LTlFBR.
/, Executive Order 13132: Executive
Orders on Federalism
Executive Order 13132, entitled
"Federalism" (64 FR 43255, August 10,
1999), requires EPA to develop an
accountable process to ensure
"meaningful and timely input by State
and local officials in the development of
regulatory policies that have federalism
implications." "Policies that have
federalism implications" is defined in
the Executive Order to include
regulations that have "substantial direct
effects on the States, on the relationship
between the national government and
the States, or on the distribution of
power and responsibilities among the
various levels of government."
Under section 6 of Executive Order
13132, EPA may not issue a regulation
that has federalism implications, that
imposes substantial direct compliance
costs, and that is not required by statute,
unless the Federal government provides
the funds necessary to pay the direct
compliance costs incurred by State and
local governments, or EPA consults with
State and local officials early in the
process of developing the proposed
regulation. EPA also may not issue a
regulation that has federalism
implications and that preempts State
law, unless the Agency consults with
State and local officials early in the
process of developing the proposed
regulation.
If EPA complies by consulting,
Executive Order 13132 requires EPA to
provide to the Office of Management
and Budget (OMB),, in a separately
identified section of the preamble to the
final rule, a federalism summary impact
statement (FSIS). The FSIS must include
a description of the extent of EPA's
prior consultation with State and local
officials, a summary of the nature of
their concerns and the agency's position
supporting the need to issue the
regulation, and a statement of the extent
to which the concerns of State and local
officials have been met. Also, when EPA
transmits a draft final rule with
federalism implications to OMB for
review pursuant to Executive Order
12866, EPA must include a certification
from the agency's Federalism Official
stating that EPA has met the
requirements of Executive Order 13132
in a meaningful and timely manner.
EPA has concluded that this proposed
rule may have federalism implications
since it may impose substantial direct
compliance costs on local governments,
and the Federal government will not
provide the funds necessary to pay
those cost. Accordingly, EPA provides
the following FSIS as required by
section 6(b) of Executive Order 13132.
As discussed further in section
VT[.C.2.e, EPA met with a variety of
State and local representatives, who
provided meaningful and timely input
in the development of the proposed
rule. Summaries of the meetings have
been included in the public record for
this proposed rulemaking. EPA
consulted extensively with State, local,
and tribal governments. For example,
two public stakeholder meetings were
held on July 22-23, 1998, in Lakewood,
Colorado, and on March 3-4, 1999, in
Dallas, Texas. Several key issues were
raised by stakeholders regarding the LT1
provisions, many of which were related
to reducing burden and maintaining
flexibility. The Office of Water was able
to significantly reduce burden and
increase flexibility by tailoring
requirements to reduce monitoring,
reporting, and recordkeeping
requirements faced by small systems.
These modifications and others aided in
lowering the cost of the LTlFBR by $87
million (from $184.5 million to $97.5
million). It should be noted that this
rule is important because it will reduce
the level of Cryptosporidium in filtered
finished drinking water supplies
through improvements in filtration and
recycle practices resulting in a reduced
likelihood of outbreaks of
cryptosporidiosis. The rule is also
expected to increase the level of :
protection from exposure to other
pathogens (i.e., Giardia and other
waterborne bacterial or viral pathogens).
Because consultation on this proposed
rule occurred before the November 2,
1999 effective date of Executive Order
13132, EPA will initiate discussions
with State and local elected officials
regarding the implications of this rule
during the public comment period.
/. Executive Order 13084: Consultation
and Coordination With Indian Tribal
Governments
Under Executive Order 13084, EPA
may not issue a regulation that is not
required by statute, that significantly or
uniquely affects the communities of
Indian tribal governments, and that
imposes substantial direct compliance
costs on those communities, unless the
Federal government provides the funds
necessary to pay the direct compliance
costs incurred by the tribal governments
or EPA consults with those
governments. If EPA complies by
consulting, Executive Order 13084
requires EPA to provide to the Office of
Management and Budget, in a separately
identified section of the preamble to the
rule, a description of the extent of EPA's
prior consultation with representatives
of affected tribal governments, a
summary of the nature of their concerns,
and a statement supporting the need to
issue the regulation. In addition,
Executive Order 13084 requires EPA to
develop an effective process permitting
elected officials and other
representatives of Indian tribal
governments "to provide meaningful
and timely input in the development of
regulatory policies on matters that
significantly or uniquely affect their
communities."
EPA has concluded that this rule may
significantly or unique affect the
communities of Indian tribal
governments. It may also impose
substantial direct compliance costs on
such communities. The Federal
government will not provide the funds
necessary to pay all the direct costs
incurred by the Tribal governments in
complying with the rule. In developing
this rule, EPA consulted with
representatives of Tribal governments .
pursuant to UMRA and Executive Order
13084. EPA held extensive meetings
that provided Indian Tribal
governments the opportunity for
meaningful and timely input in the
development of the proposed rule.
Summaries of the meetings have been
included in the public docket for this
rulemaking. EPA's consultation, the
nature of the government's concerns,
and the position supporting the need for
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this rule are discussed in Section
VII.C.2.6, which addresses compliance
with UMRA.
K. Likely Effect of Compliance with the
LTlFBR on the Technical, Financial,
and Managerial Capacity of Public
Water Systems
Section 1420(d)(3) of the SDWA as
amended requires that, in promulgating
a NPDWR, the Administrator shall
include an analysis of the likely effect
of compliance with the regulation on
the technical, financial, and managerial
capacity of public water systems. This
analysis can be found in the LTlFBR
RIA (EPA, 1999h).
Overall water system capacity is
defined in EPA guidance (EPA, 1998J) as
the ability to plan for, achieve, and
maintain compliance with applicable
drinking water standards. Capacity has
three components: technical,
managerial, and financial.
Technical capacity is the physical and
operational ability of a water system to
meet SDWA requirements. Technical
capacity refers to the physical
infrastructure of the water system,
including the adequacy of source water
and the adequacy of treatment, storage,
and distribution infrastructure. It also
refers to the ability of system personnel
to adequately operate and maintain the
system and to otherwise implement
requisite technical knowledge. A water
system's technical capacity can be
determined by examining key issues
and questions, including:
• Source water adequacy. Does the
system have a reliable source of
drinking water? Is the source of
generally good quality and adequately
protected?
• Infrastructure adequacy. Can the
system provide water that meets SDWA
standards? What is the condition of its
infrastructure, including well(s) or
source water intakes, treatment, storage,
and distribution? What is the
infrastructure's life expectancy? Does
the system have a capital improvement
plan?
• Technical knowledge and
implementation. Is the system's operator
certified? Does the operator have
sufficient technical knowledge of
applicable standards? Can the operator
effectively implement this technical
knowledge? Does the operator
understand the system's technical and
operational characteristics? Does the
system have an effective operation and
maintenance program?
Managerial capacity is the ability of a
water system to conduct its affairs to
achieve and maintain compliance with
SDWA requirements. Managerial
capacity refers to the system's;
institutional and administrative
capabilities. Managerial capacity can be
assessed through key issues and
questions, including:
• Ownership accountability. Are the
system owner(s) clearly identified? Can
they be held accountable for the system?
• Staffing and organization. Are the
system operator(s) and manager(s)
clearly identified? Is the system
properly organized and staffed? Do
personnel understand the management
aspects of regulatory requirements and
system operations? Do they have
adequate expertise to manage water
system operations? Do personnel have
the necessary licenses and
certifications?
• Effective external linkages. Does the
system interact well with customers,
regulators, and other entities? Is the
system aware of available external
resources, such as technical and
financial assistance?
Financial capacity is a water system's
ability to acquire and manage sufficient
financial resources to allow the system
to achieve and maintain compliance
with SDWA requirements. Financial
capacity can be assessed through key
issues and questions, including:
• Revenue sufficiency. Do revenues
cover costs? Are water rates and charges
adequate to cover the cost of water?
• Credit worthiness. Is the system
financially healthy? Does it have access
to capital through public or private
sources?
• Fiscal management and controls.
Are adequate books and records
maintained? Are appropriate budgeting,
accounting, and financial planning
methods used? Does the system manage
its revenues effectively?
Systems not making significant
modifications to the treatment process
to meet LTlFBR requirements are not
expected to require significantly
increased technical, financial, or
managerial capacity.
L. Plain Language
Executive Order 12866 and the
President's memorandum of June 1,
1998, require each agency to write its
rules in plain language. We invite your
comments on how to make this
proposed rule easier to understand. For
example: Have we organized the
material to suit your needs? Are the
requirements in the rule clearly stated?
Does the rule contain technical language
or jargon that is not clear? Would a
different format (grouping and order of
sections, use of headings, paragraphing)
make the rule easier to understand?
Would shorter sections make the final
rule easier to understand? Could we
improve clarity by adding tables, lists,
or diagrams? What else could we do to
make the rule easier to understand?
VIII. Public Comment Procedures
EPA invites you to provide your
views on this proposal, approaches we
have not considered, the potential
impacts of the various options
(including possible unintended
consequences), and any data or
information that you would like the
Agency to consider. Many of the
sections within today's proposed rule
contain "Request for Comment"
portions which the Agency is also
interested in receiving comment on.
A. Deadlines for Comment
Send your comments on or before
June 9, 2000. Comments received after
this date may not be considered in
decision making on the proposed rule.
Again, comments must be received or
post-marked by midnight June 9, 2000.
B. Where To Send Comment
Send an original and 3 copies of your
comments and enclosures (including
references) to W-99-10 Comment Clerk,
Water Docket (MC4101), USEPA, 401 M,
Washington, D.C. 20460. Comments
may also be submitted electronically to
ow-docket@epamail.epa.gov. Electronic
comments must be submitted as an
ASCII, WP5.1, WP6.1 or WPS file
avoiding the use of special characters
and form of encryption. Electronic
comments must be identified by the
docket number W-99-10. Comments
and data will also be accepted on disks
in WP 5.1, 6.1, 8 or ASCII file format.
Electronic comments on this notice may
be filed online at many Federal
Depository Libraries. Those who
comment and want EPA to acknowledge
receipt of their comments must enclose
a self-addressed stamped envelope. No
facsimiles (faxes) will be accepted.
Comments may also be submitted
electronically to ow-
docket@epamail.epa.gov.
C. Guidelines for Commenting
To ensure that EPA can read,
understand and therefore properly
respond to comments, the Agency
would prefer that commenters cite,
where possible, the paragraph(s) or
sections in the notice or supporting
documents to which each comment
refers. Commenters should use a
separate paragraph for each issue
discussed. Note that the Agency is not
soliciting comment on, nor will it
respond to, comments on previously
published regulatory language that is
included in this notice to ease the
reader's understanding of proposed
language. You may find the following
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Federal Register/Vol. 65, No. 69/Monday, April 10, 2000/Proposed Rules
19137
suggestions helpful for preparing your
comments:
1. Explain your views as clearly as
possible.
2. Describe any assumptions that you
used.
3. Provide solid technical information
and/or data to support your views.
4. If you estimate potential burden or
costs, explain how you arrived at the
estimate.
5. Indicate what you support, as well
as what you disagree with.
6. Provide specific examples to
illustrate your concerns.
7. Make sure to submit your
comments by the deadline in this
proposed rule.
8. At the beginning of your comments
(e.g., as part of the "Subject" heading),
be sure to properly identify the
document you are commenting on. You
can do this by providing the docket
control number assigned to the
proposed rule, along with the name,
date, and Federal Register citation.
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List of Subjects
40 CFR Part 141
Environmental protection, Chemicals,
Indians-lands, Intergovernmental
relations, Radiation protection,
Reporting and recordkeeping
requirements, Water supply.
40 CFR Part 142
Environmental protection,
Administrative practice and procedure,
Chemicals, Indians-lands, Radiation
protection, Reporting and recordkeeping
requirements, Water supply.
Dated: March 27, 2000.
Carol M. Browner,
Administrator.
For the reasons set forth in the
preamble, title 40 chapter I of the Code
of Federal Regulations is proposed to be
amended as follows:
PART 141—NATIONAL PRIMARY
DRINKING WATER REGULATIONS
3. The authority citation for part 141
continues to read as follows:
Authority: 42 U.S.C. 300f, 300g-l, 300g-2,
300g-3, 300g-4, 300g-5, 300g-6, 300J-4,
300J-9, and 300J-11.
4. Section 141.2 is amended by
revising the definition of "Ground water
under the direct influence of surface
water" and "Disinfection profile" and
adding the following definitions in
alphabetical order to read as follows:
§141.2 Definitions.
*****
Direct recycle is the return of recycle
flow within the treatment process of a
public water system without first
passing the recycle flow through a
treatment process designed to remove
solids, a raw water storage reservoir, or
some other structure with a volume
equal to or greater than the volume of
spent filter backwash water produced by
one filter backwash event.
*****
Disinfection profile is a summary of
Giardia lamblia inactivation through the
treatment plant, from the point of
disinfectant application to the first
customer. The procedure for developing
a disinfection profile is contained in
§ 141.172 (Disinfection profiling and
benchmarking) in subpart P and
§§ 141.530-141.536 (Disinfection ,
profile) in subpart T of this part.
*****
Equalization is the detention of
recycle flow in a structure with a
volume equal to or greater than the
volume of spent filter backwash
produced by one filter backwash event.
*****
Ground water under the direct
influence of surface water (GWUDI)
means any water beneath the surface of
the ground with significant occurrence
of insects or other macroorganisms,
algae, or large-diameter pathogens such
as Giardia lamblia or Cryptosporidium,
or significant and relatively rapid shifts
in water characteristics such as
turbidity, temperature, conductivity, or
pH which closely correlate to
climatological or surface water
conditions. Direct influence must be
determined for individual sources in
accordance with criteria established by
the State. The State determination of
direct influence may be based on site-
specific measurements of water quality
and/or documentation of well
construction characteristics and geology
with field evaluation.
Membrane Filtration means any
filtration process using tubular or spiral
wound elements that exhibits the ability
to mechanically separate water from
other ions and solids by creating a
pressure differential and flow across a
membrane with an absolute pore size <1
Operating capacity is the maximum
finished water production rate approved
by the State drinking water program.
*****
Recycle is the return of any water,
solid, or semisolid generated by plant
treatment processes, operational
processes, maintenance processes, and
residuals treatment processes into a
PWS's primary treatment processes.
*****
5. Section 141.32 is amended by
revising paragraph (e)(10) to read as
follows:
§ 141.32 Public notification.
*****
(e)* * *
(10) Microbiological contaminants (for
use when there is a violation of the
treatment technique requirements for
filtration and disinfection in subpart H,
subpart P, or subpart T of this part). The
United States Environmental Protection
Agency (EPA) sets drinking water
standards and has determined that the
presence of microbiological
contaminants are a health concern at '
certain levels of exposure. If water is
inadequately treated, microbiological
contaminants in that water may cause
disease. Disease symptoms may include
diarrhea, cramps, nausea, and possibly
jaundice, and any associated headaches
and fatigue. These symptoms, however,
are not just associated with disease-
causing organisms in drinking water,
but also may be caused by a number of
factors other than your drinking water.
EPA has set enforceable requirements
for treating drinking water to reduce the
risk of these adverse health effects.
Treatment such as filtering and
disinfecting the water removes or ;
destroys microbiological contaminants.
Drinking water which is treated to meet
EPA requirements is associated with
little to none of this risk and should be
considered safe.
*****
6. Section 141.70 is amended by
revising paragraph (b)(2) and adding
paragraph (e) to read as follows:
§141.70 General requirements.
*****
(b)* * *
(2) It meets the filtration requirements
in § 141.73, the disinfection
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Federal Register/Vol. 65, No, 69/Monday, April 10, 2000/Proposed Rules
requirements in § 141.72(b) and the
recycle requirements in § 141.76.
*****
(e) Additional requirements for
systems serving fewer than 10,000
people. In addition to complying with
requirements in this subpart, systems
serving fewer than 10,000 people must
also comply with the requirements in
subpart T of this part.
7. Section 141.73 is amended by
adding paragraph (a)(4) and revising
paragraph (d) to read as follows:
§141.73 Filtration.
*****
(a)* * *
(4) Beginning [DATE 36 MONTHS
AFTER DATE OF PUBLICATION OF
FINAL RULE IN THE FEDERAL
REGISTER], systems serving fewer than
10,000 people must meet the turbidity
requirements in §§ 141.550 through
141.553.
*****
(d) Other filtration technologies. A
public water system may use a filtration
technology not listed in paragraphs (a)
through (c) of this section if it
demonstrates to the State, using pilot
plant studies or other means, that the
alternative filtration technology, in
combination with disinfection treatment
that meets the requirements of
§ 141.72(b), consistently achieves 99.9
percent removal and/or inactivation of
Giardia lamblia cysts and 99.99 percent
removal and/or inactivation of viruses.
For a system that makes this
demonstration, the requirements of
paragraph (b) of this section apply.
Beginning December 17, 2001, systems
serving at least 10,000 people must meet
the requirements for other filtration
technologies in paragraph (b) of this
section. Beginning [DATE 36 MONTHS
AFTER DATE OF PUBLICATION OF
FINAL RULE IN THE FEDERAL
REGISTER], systems serving fewer than
10,000 people must meet the
requirements for treatment technologies
in §§ 141.550 throughl41.553.
8. Subpart H is amended by adding a
new § 141.76 to subpart H to read as
follows:
§ 141.76 Recycle Provisions.
(a) Public water systems employing
conventional filtration or direct
filtration that use surface water or
ground water under the direct influence
of surface water and recycle within the
treatment process must meet all
applicable requirements of this section.
Requirements are summarized in the
following table.
RECYCLE PROVISIONS FOR SUBPART H SYSTEMS
If you are a ...
(1) subpart H public water system employing conventional or direct filtration re-
turning spent filter backwash, thickener supernatant, or liquids from dewatering
processes concurrent with or downstream of the point of primary coagulant ad-
dition.
(2) Plant that is part of a subpart H public water system, employ conventional fil-
tration treatment, practice direct recycle, employ 20 or fewer filters to meet pro-
duction requirements during the highest production month in the 12 month pe-
riod [date 60 months after publication of final rule], and recycle spent filter
backwash or thickener supernatant to the treatment process.
(3) subpart H public water system practicing direct filtration and recycling to the
treatment process.
You are
required to meet the requirements in ...
§141.76(b).
§141.76(c).
§141.76(d).
(b) Recycle return location. All
subpart H systems employing
conventional filtration or direct
filtration and returning spent filter
backwash, thickener supernatant, or
liquids from dewatering processes at or
after the point of primary coagulant
addition must return these recycle flows
prior to the point of primary coagulant
addition by [DATE 60 MONTHS AFTER
DATE OF PUBLICATION OF FINAL
RULE IN THE FEDERAL REGISTER].
The system must apply to the State for
approval of the change in recycle
location before the system implements
it.
(1) All subpart H systems employing
conventional filtration or direct
filtration, returning spent filter
backwash, thickener supernatant, or
liquids from dewatering processes at or
after the point of primary coagulant
addition must submit a plant schematic
to the State by [DATE 42 MONTHS
AFTER DATE OF PUBLICATION OF
FINAL RULE IN THE FEDERAL
REGISTER] showing the current recycle
return location(s) for the recycle
stream(s) and the new return location
that will be used to establish
compliance. The system must keep the
plant schematic on file for review
during sanitary surveys.
(2) Softening systems may recycle
process solids at the point of lime
addition preceding the softening process
to improve treatment efficiency. Process
solids may not be returned prior to the
point of lime addition. Softening
systems shall not return spent filter
backwash, thickener supernatant, or
liquids from dewatering processes to a
location other than prior to the point of
primary coagulant addition unless an
alternate location is granted by the
State.
(3) Contact clarification systems may
recycle process solids directly into the
contactor. Contact clarification systems
shall not return spent filter backwash,
thickener supernatant, or liquids from
dewatering processes to a location other
than prior to the point of primary
coagulant addition unless an alternate
location is granted by the State.
(4) Systems may apply to the State to
return spent filter backwash, thickener
supernatant, or liquids from dewatering
processes to an alternate location other
than prior to the point of primary
coagulant addition.
(c) Plants that are part of subpart H
public water systems that employ
conventional rapid granular filtration,
practice direct recycle, employ 20 or
fewer filters to meet production
requirements during the highest
production month in the 12 month
period prior to [DATE 60 MONTHS
AFTER PUBLICATION OF FINAL RULE
IN THE Federal Register], and recycle
spent filter backwash or thickener
supernatant to the primary treatment
process shall complete a recycle self
assessment, as stipulated in
paragraphs(c)(l) and (c)(2) by [Date 51
Months After Date of Publication of '
Final Rule in the Federal Register].
Systems required to perform the self
assessment shall:
(1) Submit a recycle self assessment
monitoring plan to the State no later
than [Date 39 Months After Date of
Publication of Final Rule in the Federal
Register]. At a minimum, the
monitoring plan must identify the
highest water production month during
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19143
which monitoring will be conducted,
contain a schematic identifying the
location of raw and recycle flow
monitoring devices, describe the type of
flow monitoring devices to be used,
identify the system's State approved
operating capacity, and describe how
data from the raw and recycle flow
monitoring devices will be
simultaneously retrieved and recorded.
(2) Implement the following recycle
self assessment monitoring and analysis
steps:
p) Steps for Implementation of
Recycle Self Assessment:
(A) Identify the highest water
production month during the 12 month
period preceding [Date 36 Months After
Date of Publication of Final Rule in the
Federal Register].
(B) Perform the monitoring described
in paragraph (c)(2)(i)(C) of this section
during the 12 month period after
submission of the monitoring plan to
the State. The twelve month period
must begin no later than [Date 39
Months After Date of Publication of
Final Rule in the Federal Register].
(C) For each day of the month
identified in paragraph (c)(2)(i)(A) of
this section, separately monitor source
water influent flow and recycle flow
before their confluence during one filter
backwash recycle event per day, at three
minute intervals during the duration of
the event. Monitoring must be
performed between 7:00 a.m. and 8:00
p.m. Systems that do not have a filter
backwash recycle event every day
between 7:00 am and 8:00 p.m. must
monitor one filter backwash recycle
event per day, any three days of the
week, for each week during the month
of monitoring, between 7:00 a.m. and
8:00 p.m. Record the time filter
backwash was initiated, the influent and
recycle flow at three minute intervals
during the duration of the event, and the
time the filter backwash recycle event
ended. Record the number of filters in
use when the filter backwash recycle
event is monitored.
(D) Calculate the arithmetic average of
all influent and recycle flow values
taken at three minute intervals in
paragraph (c)(2)(i)(c) of this section.
Sum the arithmetic average calculated
for raw water influent and recycle flows.
Record this value and the date the
monitoring was performed. This value is
referred to as event flow.
(E) After the month of monitoring is
complete, order the event flows in a list
of increasing order, from lowest to
highest. Highlight the event flows that
exceed State approved operating
capacity and then sum the number of
event flows highlighted.
(ii) [Reserved]
(3) Subpart H systems performing
recycle self assessments are required to
report the results of the self assessment
and supporting documentation to the
State within one month of completing
raw water influent and recycle flow
monitoring. The report must be
submitted no later than [DATE 52
MONTHS AFTER DATE OF
PUBLICATION OF FINAL RULE IN
THE FEDERAL REGISTER]. If the State
determines the self assessment is
incomplete or inaccurate, it may require
the system to correct deficiencies or
perform an additional self assessment.
At a minimum, the report must contain
the following information:
(i) Minimum Information Included in
Recycle Assessment Report to State:
(A) All source and recycle flow
measurements taken and the dates they
were taken. For all events monitored,
report the times the filter backwash
recycle event was initiated, the flow
measurements taken at three minute
intervals, and the time the filter
backwash recycle event ended. Report
the number of filters in use when the
backwash recycle event is monitored,
(B) All data used and calculations
performed to determine whether the
system exceeded operating capacity
during monitored recycle events and the
number of event flow values that
exceeded State approved operating
capacity.
(C) A plant schematic showing the
origin of all recycle flows, the hydraulic
conveyance used to transport them, and
their final destination in the plant.
(D) A list of all the recycle tlows and
the frequency at which they are
returned to the plant's primary
treatment process.
(E) Average and maximum backwash
flow rate through the filters and the
average and maximum duration of the
filter backwash process, in minutes.
(F) Typical filter run length and a
written summary of how filter run
length is determined (preset run time,
headloss, turbidity breakthrough, etc.).
(ii) [Reserved]
(4) All subpart H systems performing
self assessments are required to modify
their recycle practice in accordance
with the State determination by [DATE
60 MONTHS AFTER DATE OF
PUBLICATION OF FINAL RULE IN
THE FEDERAL REGISTER] and keep a
copy of the self assessment report
submitted to die State on file for review
during sanitary surveys.
(d) Subpart H public water systems
practicing direct filtration and recycling
to the primary treatment process are
required to submit data to the State on
their current recycle treatment no later
than [DATE 42 MONTHS AFTER DATE
OF PUBLICATION OF FINAL RULE IN
THE FEDERAL REGISTER.]
(l) Direct filtration systems
submitting data to the State shall report
the following information, at a
minimum:
(i) Data Submitted to States by Direct
Filtration Systems:
(A) A plant schematic showing the
origin of all recycle flows, the hydraulic
conveyance used to transport them, and
their final destination in the plant.
(B) The number of filters used at the
plant to meet average daily production
requirements and average and
maximum backwash flow rate through
the filter and the average and maximum
duration of the filter backwash process,
in minutes.
(C) Whether recycle flow treatment or
equalization is in place.
(D) The type of treatment provided for
the recycle flow.
(E) For recycle equalization and
treatment units: data on the physical
dimensions of the unit (length, width
(or circumference), depth,) sufficient to
allow calculation of volume; typical and
maximum hydraulic loading rate; type
of treatment chemicals used and average
dose and frequency of use, and
frequency at which solids are removed
from the unit, if applicable.
(ii) [Reserved]
(2) All direct filtration systems
submitting data to the State are required
to modify their recycle practice in
accordance with the State determination
no later than [DATE 60 MONTHS
AFTER DATE OF PUBLICATION OF
FINAL RULE IN THE FEDERAL
REGISTER] and keep a copy of the
report submitted to the State on file for
review during sanitary surveys.
9. Section 141.153 is amended by
revising the first sentence of paragraph
(d)(4)(v)(C) to read as follows:
§141.153 Content of the reports.
*****
(d)* * *
(4) * * *
(V)* * *
(C) When it is reported pursuant to
§ 141.73 or § 141.173 or § 141.551: the
highest single measurement and the
lowest monthly percentage of samples
meeting the turbidity limits specified in
§ 141.73 or § 141.173, or § 141.551 for
the filtration technology being used.
10. The heading to Subpart P is
revised as follows:
Subpart P—Enhanced Filtration and
Disinfection-Systems Serving 10,000
or More People
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Federal Register/Vol. 65, No. 69/Monday, April 10, 2000/Proposed Rules
11. Section 141.170 is amended by
adding paragraph (d) to read as follows:
§141.170 General requirements.
*****
(d) Subpart H systems that did not
conduct applicability monitoring under
§ 141.172 because they served fewer
than 10,000 persons when such
monitoring was required but serve more
than 10,000 persons prior to [DATE 36
MONTHS AFTER DATE OF
PUBLICATION OF FINAL RULE IN
THE FEDERAL REGISTER] must
comply with §§ 141.170, 141.171,
141.173, 141.174, and 141.175. TJiese
systems must also consult with the State
to establish a disinfection benchmark. A
system that decides to make a
significant change to its disinfection
practice, as described in
§ 141.172(c)(lHi) through (iv) must
consult with, the State prior to making
such change.
*****
12. Part 141 is amended by adding a
new subpart T to read as follows:
Subpart T—Enhanced Filtration and
Disinfection—Systems Serving Fewer
than 10,000 People
Sec.
General Requirements
141.500 General requirements.
141.501 Who is subject to the requirements
of subpart T?
141.502 When must my system comply
with these requirements?
141.503 What does subpart T require?,
Finished Water Reservoirs
141.510 Is my system subject to the new
finished water reservoir requirements?
141.511 What is required of new finished
water reservoirs?
Additional Watershed Control Requirements
141.520 Is my system subject to the updated
watershed control requirements?
141.521 What updated watershed control'
requirements must my system comply
with?
141.522 How does the State determine
whether my system's watershed control
requirements are adequate?
Disinfection Profile
141.530 Who must develop a Disinfection
Profile and what is a Disinfection
Profile?
141.531 How does my system demonstrate
TTHM and HAAS levels below 0.064
mg/1 and 0.048 mg/1 respectively?
141.532 How does my system develop a
Disinfection Profile and when must it
begin?
141.533 What measurements must my
system collect to calculate a Disinfection
Profile?
141.534 How does my system use these
measurements to calculate an
inactivation ratio?
141.535 How does my system develop a
Disinfection Profile if we use
chloramines, ozone, or chlorine dioxide
for primary disinfection?
141.536 If my system has developed an
inactivation ratio; what must we do
now?
Disinfection Benchmark
141.540 Who has to develop a Disinfection
Benchmark?
141.541 What are significant changes to
disinfection practice?
141.542 How is the Disinfection Benchmark
calculated?
141.543 What if my system uses
chloramines or ozone for primary
disinfection?
141.544 ' What must my system do if
considering a significant change to
disinfection practices?
Combined Filter Effluent Requirements
141.550 Is my system required to meet
subpart T combined filter effluent
turbidity limits?
141.551 What strengthened combined filter
effluent turbidity limits must my system
meet?
141.552 If my system consists of
"alternative filtration" and is required to
conduct a demonstration, what is
required of my system and how does the
State establish my turbidity limits?
141.553 If my system practices lime
softening, is there any special provision
regarding my combined filter effluent?
Individual Filter Turbidity Requirements
141.560 Is my system subject to individual
filter turbidity requirements?
141.561 What happens if my turbidity
monitoring equipment fails?
141.562 What follow-up action is my
system required to take based on
turbidity monitoring of individual
filters?
141.563 My system practices lime
softening. Is there any special provision
regarding my individual filter turbidity
monitoring?
Reporting and Recordkeeping Requirements
142.570 What does subpart T require that
my system report to the State?
142.571 What records does subpart T
require my system to keep?
Subpart T—Enhanced Filtration and
Disinfection—Systems Serving Fewer Than
10,000 People
General Requirements
§ 141.500 General requirements.
The requirements of subpart T
constitute national primary drinking
water regulations. These regulations
establish requirements for filtration and
disinfection that are in addition to
criteria under which filtration and
disinfection are required under subpart
H of this part. The regulations in this
subpart establish or extend treatment
technique requirements in lieu of
maximum contaminant levels fpr the
following contaminants: Giardia
lamblia, viruses, heterotrophic plate
count bacteria, Legionella,
Cryptosporidium and turbidity. The
treatment technique requirements
consist of installing and properly
operating water treatment processes
which reliably achieve:
(a) At least 99 percent (2 log) removal
of Cryptosporidium between a point
where the raw water is not subject to
recontamination by surface water runoff
and a point downstream before or at the
first customer for filtered systems, or
Cryptosporidium control under the
watershed control plan for unfiltered
systems.
(b) Compliance with the profiling and
benchmark requirements in §§ 141.530
through 141.544.
§141.501 Who is subject to the
requirements of subpart T?
You are subject to these requirements
if your system:
(a) Is a public water system;
(b) Uses surface water or GWUDI as a
source; and
(c) Serves fewer than 10,000 persons
annually.
§141.502 When must my system comply
with these requirements?
You must comply with these
requirements beginning [DATE 36
MONTHS AFTER DATE OF
PUBLICATION OF FINAL RULE IN
THE FEDERAL REGISTER] except
where otherwise noted.
§ 141.503 What does subpart T require?
There are six requirements of this
subpart which your system may need to
comply with. These requirements are
discussed in detail later in this subpart.
They are:
(a) Any finished water reservoir for
which construction begins on or after
[DATE 60 DAYS AFTER DATE OF
PUBLICATION OF FINAL RULE IN
THE FEDERAL REGISTER] must be
covered;
(b) Unfiltered systems must comply
with updated watershed control
requirements;
(c) All systems subject to the
requirements of this subpart must
develop a disinfection profile;
(d) All systems subject to the
requirements of this subpart that are
considering a significant change to their
disinfection practice must develop a
disinfection benchmark and receive
State approval before changing their
disinfection practice;
(e) Filtered systems must comply with
specific combined filter effluent
turbidity limits and monitoring and
reporting requirements; and
(f) Filtered systems using
conventional or direct filtration must
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19145
comply with individual filter turbidity
limits and monitoring and reporting
requirements.
Finished Water Reservoirs
§ 141.510 Is my system subject to the new
finished water reservoir requirements?
All subpart H systems which serve
populations fewer than 10,000 are
subject to this requirement.
§141.511 What is required for new
finished water reservoirs?
If your system initiates construction
of a finished water reservoir after [DATE
60 DAYS AFTER DATE OF
PUBLICATION OF FINAL RULE IN
THE FEDERAL REGISTER the reservoir
must be covered. Finished water
reservoirs constructed prior to [DATE 60
DAYS AFTER DATE OF PUBLICATION
OF FINAL RULE IN THE FEDERAL
REGISTER are not subject to this
requirement,
Additional Watershed Control
Requirements
§ 141.520 Is my system subject to the
updated watershed control requirements?
If you are a subpart H system serving
fewer than 10,000 persons which does
not provide filtration, you must
continue to comply with all of the
watershed control requirements in
§ 141.71, as well as the additional
watershed control requirements in
§141.521.
§ 141.521 What additional watershed
control requirements must my system
comply with?
Your system must also maintain the
existing watershed control program to
minimize the potential for
contamination by Cryptosporidium
oocysts in the source water. Your
system's watershed control program
must, for Cryptosporidium:
(a) Identify watershed characteristics
and activities which may have an
adverse effect on source water quality;
and
(b) Monitor the occurrence of
activities which may have an adverse
effect on source water quality.
§ 141.522 How does the State determine
whether my system's watershed control
requirements are adequate?
During an onsite inspection
conducted under the provisions of
§ 141.71 [b)(3), the State must determine
whether your watershed control
program is adequate to limit potential
contamination by Cryptosporidium
oocysts. The adequacy of the program
must be based on the
comprehensiveness of the watershed
review; the effectiveness of your
program to monitor and control
detrimental activities occurring in the
watershed; and the extent to which your
system has maximized land ownership
and/or controlled land use within the
watershed.
Disinfection Profile
§ 141.530 Who must develop a
Disinfection Profile and what is a
Disinfection Profile?
All subpart H community and non-
transient non-community water systems
which serve fewer than 10,000 persons
must develop a disinfection profile. A
disinfection profile is a graphical
representation of your system's level of
Giardia lamblia or virus inactivation
measured during the course of a year.
Your system must develop a
disinfection profile unless you can
demonstrate to the State that your
TTHM and HAAS levels are less than
0.064 mg/1 and 0.048 mg/1 respectively,
prior to January 7, 2003.
§ 141.531 How does my system
demonstrate TTHM and HAAS levels below
0.064 mg/l and 0.048 mg/l respectively?
In order to demonstrate that your
TTHM and HAAS levels are below 0.064
mg/L and 0.048 mg/L, respectively your
system must have collected one TTHM
and one HAAS sample taken between
1998-2002. Samples must have been
collected during the month with the
warmest water temperature, at the point
of maximum residence time in your
distribution system which indicate
TTHM levels below 0.064 mg/l and
HAAS levels below 0.048 mg/L. By
January 7, 2003, you must submit a copy
of the results to the State along with a
letter indicating your intention to forgo
development of a disinfection profile
because of the results of the sampling.
This letter, along with a copy of your
TTHM and HAAS sample lab results
must be kept on file for review by the
State during a sanitary survey. If the
data you have collected is either equal
to or exceeds either 0.064 mg/l for
TTHM and/or 0.048 mg/l for HAASs,
you must develop a disinfection profile.
§ 141.532 How does my system develop a
Disinfection Profile and when must it
begin?
A disinfection profile consists of three
steps:
(a) First, your system must collect
measurements for several treatment
parameters from the plant as discussed
in § 141.533. Your system must begin
this monitoring no later than January 7,
2003.
(b) Second, your system must use
these measurements to calculate
inactivation ratios as discussed in
§§ 141.534 and 141.535; and
(c) Third, your system must use these
inactivation ratios to develop a
disinfection profile as discussed in
§141.536.
§ 141.533 What measurements must my
system collect to calculate a Disinfection
Profile?
Your system must monitor the
parameters necessary to determine the
total inactivation ratio using analytical
methods in § 141.74 (a), once per week
on the same calendar day each week as
follows:
(a) The temperature of the disinfected
water must be measured at each residual
disinfectant concentration sampling
point during peak hourly flow;
(b) If the system uses chlorine, the pH
of the disinfected water must be
measured at each chlorine residual
disinfectant concentration sampling
point during peak hourly flow;
(c) The disinfectant contact time(s)
("T") must be determined during peak
hourly flow; and
(d) The residual disinfectant
concentration(s) ("C") of the water
before or at the first customer and prior
to each additional point of disinfection
must be measured during peak hourly
flow.
§ 141.534 How does my system use these
measurements to calculate an inactivation
ratio?
Calculate the total inactivation ratio
as follows, and multiply the value by
3.0 to determine log inactivation of
Giardia lamblia:
If a system...
The system must determine...
(a) Uses only one point of disinfectant application
(1) One inactivation ratio (CTcalc/CT99.9) before or at the first customer
during peak hourly flow, or
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Federal Register/Vol. 65, No. 69/Monday, April 10, 2000/Proposed Rules
If a system...
The system must determine...
(b) Uses more than one point of disinfectant application before the first
customer.
(2) Successive CTcalc/CT99.9 values, representing sequential inactiva-
tion ratios, between the point of disinfectant application and a point
before or at the first customer during peak hourly flow. Under this al-
ternative, the system must calculate the total inactivation ratio by de-
termining (CTcaIc/CT99.9) for each sequence and then adding the
(CTcalc/CT99.9) values together to determine (Z (CTcalc/CT99.9)). You
may use a spreadsheet that calculates CT and/or contains the nec-
essary inactivation tables.
(1) The CTcalc/CT99.9 value of each disinfection segment immediately
prior to the next point of disinfectant application, or for the final seg-
ment, before or at the first customer, during peak hourly flow using
the procedure described in the above paragraph.
§ 141.535 How does my system develop a
Disinfection Profile if we use chloramines,
ozone, or chlorine dioxide for primary
disinfection?
If your system uses either
chloramines, ozone or chlorine dioxide
for primary disinfection, you must also
calculate the logs of inactivation for
viruses. You must develop an additional
disinfection profile for viruses using a
method approved by the State.
§ 141.536 If my system has developed an
inactivation ratio, what must we do now?
Each inactivation ratio serves as a
data point in your disinfection profile.
Your system will have obtained 52
measurements (one for every week of
the year). This will allow your system
and the State the opportunity to
evaluate how microbial inactivation
varied over the course of the year by
looking at all 52 measurements (your
Disinfection Profile). Your system must
retain the Disinfection Profile data in
graphic form, as a spreadsheet, or in
some other format acceptable to the
State for review as part of sanitary
surveys conducted by the State. Your
system will need to use this data to
calculate a benchmark if considering
changes to disinfection practices.
Disinfection Benchmark
§ 141.540 Who has to develop a
Disinfection Benchmark?
If you are a subpart H system required
to develop a disinfection profile under
§§ 141.530 through 141.536, your
system must develop a Disinfection
Benchmark if you decide to make a
significant change to disinfection
practice. State approval must be
obtained before you can implement a
significant disinfection practice change.
§ 141.541 What are significant changes to
disinfection practice?
Significant changes to disinfection
practice are:
(a) Changes to the point of
disinfection;
(b) Changes to the disinfectant(s) used
in the treatment plant;
(c) Changes to the disinfection
process; or
(d) Any other modification identified
by the State.
§ 141.542 How is the Disinfection
Benchmark Calculated?
If your system is making a significant
change to its disinfection practice, it
must calculate a disinfection benchmark
using the following procedure:
(a) To calculate a disinfection
benchmark a system must perform the
following steps:
Step 1: Using the data your system
collected to develop the Disinfection
Profile, determine the average Giardia
lamblia inactivation for each calender
month by dividing the sum of all
Giardia lamblia inactivations for that
month by the number of values
calculated for that month.
Step 2: Determine the lowest monthly
average value out of the twelve values.
This value becomes the disinfection
benchmark.
(b) [Reserved]
§ 141.543 What if my system uses
chloramines or ozone for primary
disinfection?
If your system uses chloramines,
ozone or chlorinated dioxide for
primary disinfection your system must
calculate the disinfection benchmark
from the data your system collected for
viruses to develop the disinfection
profile in addition to the Giardia
lamblia disinfection benchmark
calculated under § 141.542. The
disinfection benchmark must be
calculated as described in §141.542.
§ 141.544 What must my system do if
considering a significant change to
disinfection practices?
If your system is considering a
significant change to the disinfection
practice, it must complete a disinfection
benchmark(s) as described in §§ 141.542
and 141.543 and provide the
benchmark(s) to your State. Your system
may only make a significant disinfection
practice change after receiving State
approval. The following information
must be submitted to the State as part
of their review and approval process:
(a) A description of the proposed
change;
(b) The disinfection profile for Giardia
lamblia (and, if necessary, viruses) and
disinfection benchmark;
(c) An analysis of how the proposed
change will affect the current levels of
disinfection; and
(d) Additional information requested
by the State.
Combined Filter Effluent Requirements
§ 141.550 Is my system required to meet
subpart T combined filter effluent turbidity
limits?
All subpart H systems •which serve
populations fewer than 10,000, and are
required to filter, must meet combined
filter effluent requirements. Unless your
system consists of slow sand or
diatomaceous earth filtration, you are
required to meet the combined filter
effluent turbidity limits in § 141.551. If
your system uses slow sand or
diatomaceous earth filtration you must
continue to meet the combined filter
effluent turbidity limits in § 141.73.
§ 141.551 What strengthened combined
filter effluent turbidity limits must my
system meet?
Your system must meet two
strengthened combined filter effluent
turbidity limits.
(a) The first combined filter effluent
turbidity limit is a "95th percentile"
turbidity limit which your system must
meet in at least 95 percent of the
turbidity measurements taken each
month. Measurements must continue to
be taken as described in § 141.74(a) and
(c). The following table describes the
required limits for specific filtration
technologies.
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19147
If your system consists of ...
Your 95th percentile turbidity value is ...
(1) Conventional filtration or direct filtration
(2) Membrane filtration
(3) All other "alternative" filtration
0.3 NTU.
0.3 NTU or a value determined by the State (not to exceed 1 NTU)
based on a demonstration conducted by the system as described in
§141.552.
A value determined by the State (not to exceed 1 NTU) based on the
demonstration described in § 141.552.
(b) The second combined filter
effluent turbidity limit is a "maximum"
turbidity limit which your system may
at no time exceed during the month.
Measurements must continue to be
taken as described in § 141.74(a) and (c).
The following table describes the
required limits for specific filtration
technologies.
If your system consists of ...
(3) AH other "alternative" filtration
Your maximum turbidity value is ...
1 NTU.
1 NTU or a value determined by the State (not to exceed 5 NTU)
based on a demonstration conducted by the system as described in
§141.552.
A value determined by the State (not to exceed 5 NTU) based on the
demonstration as described in §141.552.
§141.552 If my system consists of
"alternative filtration" and is required to
conduct a demonstration, What is required
of my system and how does the State
establish my turbidity limits?
(a) If your system is required to
conduct a demonstration (see tables in
§ 141,551), your system must
demonstrate to the State, using pilot
plant studies or other means, that your
system's filtration, in combination with
disinfection treatment, consistently
achieves:
(1) 99.9 percent removal and/or
inactivation of Giardia lamblia cysts;
(2) 99.99 percent removal and/or
inactivation of viruses; and
(3) 99 percent removal of
Qyptosporidium oocysts.
(b) If the State approves your
demonstration, it will set turbidity
performance requirements that your
system must meet:
(1) At least 95 percent of the time (not
to exceed 1 NTU); and
(2) That your system must not exceed
at any time (not to exceed 5 NTU).
§ 141.553 If my system practices lime
softening, is there any special provision
regarding my combined filter effluent?
If your system practices lime
softening, you may acidify
representative combined filter effluent
turbidity samples prior to analysis using
a protocol approved by the State.
Individual Filter Turbidity
Requirements
§ 141.560 Is my system subject to
individual filter turbidity requirements?
If your system is a subpart H system
serving fewer than 10,000 people and
utilizing conventional filtration or direct
filtration, you must conduct continuous
monitoring of turbidity for each
individual filter at your system. The
following requirements apply to
individual filter turbidity monitoring:
(a) Monitoring must be conducted
using an approved method in
§141.74(a);
(b) Calibration of turbidimeters must
be conducted using procedures
specified by the manufacturer;
(c) Results of individual filter
turbidity monitoring must be recorded
every 15 minutes;
(d) Monthly reporting must be
completed according § 141.570; and
(e) Records must be maintained
according to § 141.571.
§ 141 .!>61 What happens if my system's
turbidity monitoring equipment fails?
If there is a failure in the continuous
turbidity monitoring equipment, the
system must conduct grab sampling
every four hours in lieu of continuous
monitoring until the turbidimeter is
back on-line. A system has five working
days to resume continuous monitoring
before a violation is incurred.
§ 141.562 What follow-up action is my
system required to take based on turbidity
monitoring of individual filters?
Follow-up action is required
according to the following tables:
If the turbidity of an individual filter exceeds...
(a) If the turbidity of an individual filter exceeds 1 .0 NTU (in two con-
secutive recordings).
The system must...
Submit an exceptions report to the State by the 10th of the month
which includes the filter nurnber(s), corresponding date(s), and the
turbidity value(s) which exceeded 1 .0 NTU.
If an exceptions report is submitted for the same filter...
The system must...
(b) If an exceptions report is submitted for the same filter three months
in a row.
Conduct a self-assessment of the filter within 14 days of the exceed-
ance and report that the self assessment was conducted by the 10th
of the following month. The self assessment must consist of at least
the following components: Assessment of filter performance; devel-
opment of a filter profile; identification and prioritization of factors lim-
iting filter performance; assessment of the applicability of corrections;
and preparation of a filter self-assessment report.
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Federal Register/Vol. 65, No. 69/Monday, April 10, 2000/Proposed Rules
If an
exceptions
report
is submitted
for the same
filter...
The
system
must...
(c) If an exceptions report is submitted for the same filter two months in
a row and both months contain exceedances of 2.0 NTU (in 2 con-
secutive recordings).
(1) Arrange to have a comprehensive performance evaluation (CPE)
conducted by the State or a third party approved by the State no
later than 30 days following the exceedance and have the evaluation
completed and submitted to the State no later than 90 days following
the exceedance, Unless—
(2) A CPE has been completed by the State or a third party approved
by the State within the 12 prior months or the system and State are
jointly participating in an ongoing Comprehensive Technical Assist-
ance (CTA) project at the system.
§ 141.563 My system practices lime
softening. Is there any special provision
regarding my individual filter turbidity
monitoring?
If your system utilizes lime softening,
you may apply to the State for
alternative turbidity exceedance levels
for the levels specified in the table in
§ 141.562. You must be able to
demonstrate to the State that higher
turbidity levels in individual filters are
due to lime carryover only, and not due
to degraded filter performance.
Reporting and Recordkeeping
Requirements
§ 141.570 What does subpart T require that
my system report to the State?
This subpart T requires your system
to report several items to the State. The
following table describes the items
which must be reported and the
frequency of reporting. Your system is
required to report the information
described below, if it is subject to the
specific requirement shown in the first
column.
Corresponding requirement
(a) Combined Filter Effluent Re-
quirements.
(b) Individual Filter Turbidity Re-
quirements.
(c) Disinfection Profiling
(d) Disinfection Benchmarking
Description of information to report
(1)The total number of filtered water turbidity measurements taken
during the month.
(2) The number and percentage of filtered water turbidity measure-
ments taken during the month which are greater than your sys-
tem's required 95th percentile limit.
(3) The date and value of any turbidity measurements taken during
the month which exceed the maximum turbidity value for your fil-
tration system.
(1) That your system conducted individual filter turbidity monitoring
during the month.
(2) The filter number(s), corresponding date(s), and the turbidity
value(s) which exceeded 1 .0 NTU during the month..
(3) That a self assessment was conducted within 14 days of the date
it was triggered.
(4) That a CPE is required and the date that it was triggered
(5) Copy of completed CPE report
(1) Results of applicability monitoring which show TTHM levels
<0.064 mg/l and HAAS levels <0.048 mg/l. (Only if your system
wishes to forgo profiling) or that your system has begun disinfec-
tion profiling.
tern's disinfection profile for Giardia lamblia (and, if necessary, vi-
ruses) and disinfection benchmark, and an analysis of how the
proposed change will affect the current levels of disinfection.
Frequency
By the 10th of the following
month.
By the 10th of the following
month.
(i) Within 24 hours of exceedance
and
(ii) By the 10th of the following
month.
By the 10th of the following
month.
By the 10th of the following month
only if —
(ii) 2 consecutive values exceeded
1.0 NTU.
(i) By the 10th of the following
month (or 14 days after the self
assessment was triggered only
if the self assessment was trig-
gered during the last four days
of the month) only if —
(ii) A self-assessment is required.
(i) By the 10th of the following
month only if —
(ii) A CPE is required.
Within 90 days after the CPE was
triggered.
. ' .
ering a significant change to its
disinfection practice.
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Federal Register/Vol. 65, No. 69/Monday, April 10, 2000/Proposed Rules
19149
§141.571 What records does subpart T
require my system to keep?
Your system must keep several types
of records based on the requirements of
the necessary records, the length of time subject to the specific requirement
these records must be kept, and for
which requirement the records pertain.
Your system is required to maintain
subpart T. The following table describes records described in this table, if it is
shown in the first column. For example,
if your system uses slow sand filtration,
you would not be required to keep
individual filter turbidity records:
Corresponding requirement
qulrements.
(b) Disinfection Profiling
(c) Disinfection Benchmarking
(d) Covered Reservoirs
Description of necessary records
Results of individual filter monitoring
Results of Profile (including raw data and analysis)
Benchmark (including raw data and analysis)
Date of construction for all uncovered finished water reservoirs uti-
lized by your system.
Duration of time records must be
kept
At least 3 years.
Indefinitely.
Indefinitely.
Indefinitely.
PART 142—NATIONAL PRIMARY
DRINKING WATER REGULATIONS
IMPLEMENTATION
13. The authority citation for Part 142
continues to read as follows:
Authority: 42 U.S.C. 300f, 300g-l, 300g-2,
300g-3, 300g~4, 300g-5, 300g-6, 300J-4,
300J-9, and 300J-11.
14. Section 142.14 is amended by
revising paragraphs (a)(3), (a)(4)(i),
(a)(4)(ii) introductory text, and (a}(7) to
read as follows:
§ 142.14 Records kept by States.
fa)* * *
(3) Records of turbidity measurements
must be kept for not less than one year.
The information retained must be set
forth in a form which makes possible
comparison with the limits specified in
§§141.71,141.73,141.173 and 141.175,
141.550-141.553 and 141.560-141.563
of this chapter. Until June 29,1993, for
any public water system which is
providing filtration treatment and until
December 30,1991, for any public water
system not providing filtration
treatment and not required by the State
to provide filtration treatment, records
kept must be set forth in a form which
makes possible comparison with the
limits contained in § 141.13 of this
chapter.
*****
(4)(i) Records of disinfectant residual
measurements and other parameters
necessary to document disinfection
effectiveness in accordance with
§§ 141.72 and 141.74 of this chapter and
the reporting requirements of §§ 141.75,
141.175, and 141.570, of this chapter
must be kept for not less than one year.
(ii) Records of decisions made on a
system-by-system and case-by-case basis
under provisions of part 141, subpart H,
subpart P, or subpart T of this chapter,
must be made in writing and kept at the
State.
(7) Any decisions made pursuant to
the provisions of part 141, subpart P or
subpart T of this chapter.
(i) Records of systems consulting with
the State concerning a modification to
disinfection practice under
§§141.172(c), 141.170(d), and 141.544
of this chapter, including the status of
the consultation or approval.
(ii) Records of decisions that a system
using alternative filtration technologies,
as allowed under §§ 141.173(b) and
§ 141.552 of this chapter, can
consistently achieve a 99.9 percent
removal and/or inactivation of Giardia
lamblia cysts, 99.99 percent removal
and/or inactivation of viruses, and 99
percent removal of Cryptosporidium
oocysts. The decisions must include
State-set enforceable turbidity limits for
each system. A copy of the decision
must be kept until the decision is
reversed or revised. The State must
provide a copy of the decision to the
system.
(iii) Records of systems required to do
filter self-assessment, CPE, or CCP
under the requirements of § 141.175 and
§ 141.562 of this chapter.
*****
15. Section 142.15 is amended by
adding paragraphs (c)(6) and (c)(7) and
MM.
§ 142.15 Reports by States.
*****
(c)* * *
(6) Recycle return location. A list of
all systems moving the recycle return
location prior to the point of primary
coagulant addition. The list must also
contain all the systems the State granted
alternate recycle locations, describe the
alternative recycle return location, and
briefly discuss the reason(s) the
alternate recycle location was granted
and is due [DATE 60 MONTHS AFTER
DATE OF PUBLICATION OF FINAL
RULE IN THE FEDERAL REGISTER].
(7) Self assessment determination. A
list of all systems performing self
assessments must be reported to EPA.
The list must state whether individual
plants exceeded State approved
operating capacity during self
assessment monitoring and whether the
State required modification to recycle
practice. A brief description of the
modification to recycle practice
required at each plant must be provided.
If a plant exceeded State approved
operating capacity, and the State did not
require modification of recycle practice,
the State must provide a brief
explanation for this decision. Self
assessment results must be reported no
later than [DATE 54 MONTHS AFTER
DATE OF PUBLICATION OF FINAL
RULE IN THE FEDERAL REGISTER].
(8) Direct filtration determination. A
list of all direct filtration systems
recycling within the treatment process
must be submitted to EPA. The list must
state which systems were required to
modify recycle practice and briefly
describe the modification and the
reason it was required. It must also
identify systems not required to modify
recycle practice and provide a brief
description of the reason modification
to recycle practice was not required.
The list must be submitted no later than
[DATE 54 MONTHS AFTER DATE OF
PUBLICATION OF FINAL RULE IN
THE FEDERAL REGISTER].
*****
16. Section 142.16 is amended by
adding paragraph (b)(2)(v), (b)(2)(vi),
and (b)(2Kvii) and (i) to read as follows:
§ 142.1(5 Special primacy requirements.
*****
(b)* * *
(2)* * *
(v) The application must describe the
criteria the State will use to determine
alternate recycle locations for public
water systems applying to return spent
filter backwash, thickener supernatant,
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19150
Federal Register/Vol. 65, No. 69/Monday, April 10, 2000/Proposed Rules
or liquids from dewatering to an
alternate location other than prior to the
point of primary coagulant addition.
(vi) The application must describe the
criteria the State will use to determine
whether public water systems
completing self assessments are
required to modify recycle practice and
the criteria that will be used to specify
modifications to recycle practice.
(vii) The application must describe
the criteria the State will use to
determine whether direct filtration
systems are required to change recycle
practice and the criteria that will be
used to specify changes to recycle
practice.
*****
(i) Requirements for States to adopt
40 CFR part 141, subpart T Enhanced
Filtration and Disinfection. In addition
to the general primacy requirements
enumerated elsewhere in this part,
including the requirement that State
provisions are no less stringent than the
federal requirements, an application for
approval of a State program revision
that adopts 40 CFR part 141, subpart T
Enhanced Filtration and Disinfection,
must contain the information specified
in this paragraph;
(1) Enforceable requirements. States
must have rules or other authority to
require systems to participate in a
Comprehensive Technical Assistance
(CTA) activity, the performance
improvement phase of the Composite
Correction Program (CCP). The State
shall determine whether a CTA must be
conducted based on results of a CPE
which indicate the potential for
improved performance, and a finding by
the State that the system is able to
receive and implement technical
assistance provided through the CTA. A
CPE is a thorough review and analysis
of a system's performance-based
capabilities and associated
administrative, operation and
maintenance practices. It is conducted
to identify factors that may be adversely
impacting a plant's capability to achieve
compliance. During the CTA phase, the
system must identify and systematically
address factors limiting performance.
The CTA is a combination of utilizing
CPE results as a basis for follow-up,
implementing-process control priority-
setting techniques and maintaining
long-term involvement to systematically
train staff and administrators.
(2) State practices or procedures, (i)
Section 141.536 of this chapter—How
the State will approve a method to
calculate the logs of inactivation for
viruses for a system that uses either
chloramines or ozone for primary
disinfection.
(ii) Section 141.544 of this chapter—
How the State will approve
modifications to disinfection practice.
(iii) Section 141.552 of this chapter—
For filtration technologies other than
conventional filtration treatment, direct
filtration, slow sand nitration,
diatomaceous earth filtration, or
membrane filtration, how the State will
determine that a public water system
may use a filtration technology if the
PWS demonstrates to the State, using
pilot plant studies or other means, that
the alternative filtration technology (or
membrane filtration), in combination
with disinfection treatment that meets
the requirements of § 141.72(b) of this
chapter, consistently achieves 99.9
percent removal and/or inactivation of
Giardia lamblia cysts and 99.99 percent
removal and/or inactivation of viruses,
and 99 percent removal of
Cryptosporidium oocysts. For a system
that makes this demonstration, how the
State will set turbidity performance
requirements that the system must meet
95 percent of the time and that the .
system may not exceed at any time at a
level that consistently achieves 99.9
percent removal and/or inactivation of
Giardia lamblia cysts, 99.99 percent
removal and/or inactivation of viruses,
and 99 percent removal of
Cryptosporidium oocysts.
[FR Doc. 00-8155 Filed 4-7-00; 8:45 am]
BILLING CODE 6560-50-P
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