EPA 815-Z-03-004
Monday,
August 11, 2003
Part II
Environmental
Protection Agency
40 CFR Parts 141 and 142
National Primary Drinking Water
Regulations: Long Term 2 Enhanced
Surface Water Treatment Rule; Proposed
Rule
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47640
Federal Register/Vol. 68, No. 154/Monday, August 11, 2003/Proposed Rules
ENVIRONMENTAL PROTECTION
AGENCY
40 CFR Parts 141 and 142
IFRL-7530-5]
RIN 2040—AD37
National Primary Drinking Water
Regulations: Long Term 2 Enhanced
Surface Water Treatment Rule
AGENCY: Environmental Protection
Agency.
ACTION: Proposed rule.
SUMMARY: In this document, the
Environmental Protection Agency (EPA)
is proposing National Primary Drinking
Water Regulations that require the use
of treatment techniques, along with
monitoring, reporting, and public
notification requirements, for all public
water systems (PWSs) that use surface
water sources. The purposes of the Long
Term 2 Enhanced Surface Water
Treatment Rule (LT2ESWTR) are to
improve control of microbial pathogens,
including specifically the protozoan
Cryptosporidium, in drinking water and
to address risk-risk trade-offs with the
control of disinfection byproducts. Key
provisions in today's proposed
LT2ESWTR include the following:
source water monitoring for
Cryptosporidium, with reduced
monitoring requirements for small
systems; additional Cryptosporidium
treatment for filtered systems based on
source water Cryptosporidium
concentrations; inactivation of
Cryptosporidium by all unfiltered
systems; disinfection profiling and
benchmarking to ensure continued
levels of microbial protection while
PWSs take the necessary steps to
comply with new disinfection
byproduct standards; covering, treating,
or implementing a risk management
plan for uncovered finished water
storage facilities; and criteria for a
number of treatment and management
options (i.e., the microbial toolbox) that
PWSs may implement to meet
additional Cryptosporidium treatment
requirements. The LT2ESWTR will
build upon the treatment technique
requirements of the Interim Enhanced
Surface Water Treatment Rule and the
Long Term 1 Enhanced Surface Water
Treatment Rule.
EPA believes that implementation of
the LT2ESWTR will significantly reduce
levels of Cryptosporidium in finished
drinking water. This will substantially
lower rates of endemic
cryptosporidiosis, the illness caused by
Cryptosporidium, which can be severe
and sometimes fatal in sensitive
subpopulations (e.g., AIDS patients, the
elderly). In addition, the treatment
technique requirements of this proposal
are expected to increase the level of
protection from exposure to other
microbial pathogens (e.g., Giardia
lamblia}.
DATES: EPA must receive public
comment on the proposal by November
10,2003.
ADDRESSES: Comments may be
submitted by mail to: Water Docket,
Environmental Protection Agency, Mail
Code 4101T, 1200 Pennsylvania Ave.,
NW., Washington, DC 20460, Attention
Docket ID No. OW-2002-0039.
Comments may also be submitted
electronically or through hand delivery/
courier by following the detailed
instructions as provided in section I.C.
of the SUPPLEMENTARY INFORMATION
section.
FOR FURTHER INFORMATION CONTACT: For
technical inquiries, contact Daniel
Schmelling, Office of Ground Water and
Drinking Water (MC 4607M), U.S.
Environmental Protection Agency, 1200
Pennsylvania Ave., NW., Washington,
DC 20460; telephone (202) 564-5281.
For regulatory inquiries, contact Jennifer
McLain at the same address; telephone
(202) 564-5248. For general information
contact the Safe Drinking Water Hotline,
Telephone (800) 426^791. The Safe
Drinking Water Hotline is open Monday
through Friday, excluding legal
holidays, from 9 a.m. to 5:30 p.m.
Eastern Time.
SUPPLEMENTARY INFORMATION:
1. General Information
A. Who Is Regulated by This Action?
Entities potentially regulated by the
LT2ESWTR are public water systems
(PWSs) that use surface water or ground
water under the direct influence of
surface water (GWUDI). Regulated
categories and entities are identified in
the following chart.
Category
Industry
State, Local,
Tribal or
Federal
Govern-
ments.
Examples of regulated enti-
ties
Public Water Systems that
use surface water or
ground water under the di-
rect influence of surface
water.
Public Water Systems that
use surface water or
ground water under the di-
rect influence of surface
water.
This table is not intended to be
exhaustive, but rather provides a guide
for readers regarding entities likely to be
regulated by this action. This table lists
the types of entities that EPA is now
aware could potentially be regulated by
this action. 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
Title 40 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
LT2ESWTR to a particular entity,
consult one of the persons listed in the
preceding section entitled FOR FURTHER
INFORMATION CONTACT
B. How Can I Get Copies of This
Document and Other Related
Information?
1. Docket. EPA has established an
official public docket for this action
under Docket ID No. OW-2002-0039.
The official public docket consists of the
documents specifically referenced in
this action, any public comments
received, and other information related
to this action. Although a part of the
official docket, the public docket does
not include Confidential Business
Information (CBI) or other information
whose disclosure is restricted by statute.
The official public docket is the
collection of materials that is available
for public viewing at the Water Docket
in the EPA Docket Center, (EPA/DC)
EPA West, Room B102,1301
Constitution Ave., NW., Washington,
DC. The EPA Docket Center Public
Reading Room is open from 8:30 a.m. to
4:30 p.m., Monday through Friday,
excluding legal holidays. The telephone
number for the Public Reading Room is
(202) 566-1744, and the telephone
number for the Water Docket is (202)
566-2426. For access to docket material,
please call (202) 566-2426 to schedule
an appointment.
2. Electronic Access. You may access
this Federal Register document
electronically through the EPA Internet
under the "Federal Register" listings at
h Up -.//www.epa .gov/fedrgstr/.
An electronic version of the public
docket is available through EPA's
electronic public docket and comment
system, EPA Dockets. You may use EPA
Dockets at http://www.epa.gov/edocket/
to submit or view public comments,
access the index listing of the contents
of the official public docket, and to
access those documents in the public
docket that are available electronically.
Once in the system, select "search,"
then key in the appropriate docket
identification number.
Certain types of information will not
be placed in the EPA Dockets.
Information claimed as CBI and other
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Federal Register/Vol. 68, No. 154/Monday, August 11, 2003/Proposed Rules
47641
information whose disclosure is
restricted by statute, which is not
included in the official public docket,
will not be available for public viewing
in EPA's electronic public docket. EPA's
policy is that copyrighted material will
not be placed in EPA's electronic public
docket but will be available only in
printed, paper form in the official public
docket. Although not all docket
materials may be available
electronically, you may still access any
of the publicly available docket
materials through the docket facility
identified in section I.B.I.
For public commenters, it is
important to note that EPA's policy is
that public comments, whether
submitted electronically or in paper,
will be made available for public
viewing in EPA's electronic public
docket as EPA receives them and
without change, unless the comment
contains copyrighted material, CBI, or
other information whose disclosure is
restricted by statute. When EPA
identifies a comment containing
copyrighted material, EPA will provide
a reference to that material in the
version of the comment that is placed in
EPA's electronic public docket. The
entire printed comment, including the
copyrighted material, will be available
in the public docket.
Public comments submitted on
computer disks that are mailed or
delivered to the docket will be
transferred to EPA's electronic public
docket. Public comments that are
mailed or delivered to the Docket will
be scanned and placed in EPA's
electronic public docket. Where
practical, physical objects will be
photographed, and the photograph will
be placed in EPA's electronic public
docket along with a brief description
written by the docket staff.
C. How and to Whom Do I Submit
Comments;'
You may submit comments
electronically, by mail, or through hand
deli very/courier. To ensure proper
receipt by EPA, identify the appropriate
docket identification number in the
subject line on the first page of your
comment. Please ensure that your
comments are submitted within the
specified comment period. Comments
received after the close of the comment
period will be marked "late." EPA is not
required to consider these late
comments.
1. Electronically. If you submit an
electronic comment as prescribed
below, EPA recommends that you
include your name, mailing address,
and an e-mail address or other contact
information in the body of your
comment. Also include this contact
information on the outside of any disk
or CD ROM you submit, and in any
cover letter accompanying the disk or
CD ROM. This ensures that you can be
identified as the submitter of the
comment and allows EPA to contact you
in case EPA cannot read your comment
due to technical difficulties or needs
further information on the substance of
your comment. EPA's policy is that EPA
will not edit your comment, and any
identifying or contact information
provided in the body of a comment will
be included as part of the comment that
is placed in the official public docket,
and made available in EPA's electronic
public docket. If EPA cannot read your
comment due to technical difficulties
and cannot contact you for clarification,
EPA may not be able to consider your
comment.
a. EPA Dockets. Your use of EPA's
electronic public docket to submit
comments to EPA electronically is
EPA's preferred method for receiving
comments. Go directly to EPA Dockets
at http://www.epa.gov/edocket, and
follow the online instructions for
submitting comments. Once in the
system, select "search," and then key in
Docket ID No. OW-2002-0039. The
system is an "anonymous access"
system, which means EPA will not
know your identity, e-mail address, or
other contact information unless you
provide it in the body of your comment.
b. E-mail. Comments may be sent by
electronic mail (e-mail) to OW-
Docket@epa.gov, Attention Docket ID
No. OW-2002-0039. In contrast to
EPA's electronic public docket, EPA's e-
mail system is not an "anonymous
access" system. If you send an e-mail
comment directly to the Docket without
going through EPA's electronic public
docket, EPA's e-mail system
automatically captures your e-mail
address. E-mail addresses that are
automatically captured by EPA's e-mail
system are included as part of the
comment that is placed in the official
public docket, and made available in
EPA's electronic public docket.
c. Disk or CD ROM. You may submit
comments on a disk or CD ROM that
you mail to the mailing address
identified in section I.C.2. These
electronic submissions will be accepted
in WordPerfect or ASCII file format.
Avoid the use of special characters and
any form of encryption.
2. By Mail. Send three copies of your
comments and any enclosures to: Water
Docket, Environmental Protection
Agency, Mail Code 4101T, 1200
Pennsylvania Ave., NW., Washington,
DC, 20460, Attention Docket ID No,
OW-2002-0039.
3. By Hand Delivery or Courier.
Deliver your comments to: Water
Docket, EPA Docket Center,
Environmental Protection Agency,
Room B102,1301 Constitution Ave.,
NW, Washington, DC, Attention Docket
ID No. OW-2002-0039. Such deliveries
are only accepted during the Docket's
normal hours of operation as identified
in section I.B.I.
D. What Should I Consider as I Prepare
My Comments for EPA?
You may find the following
suggestions helpful for preparing your
comments:
1. Explain your views as clearly as
possible.
2. Describe any assumptions that you
used.
3. Provide any technical information
and/or data you used that support your
views.
4. If you estimate potential burden or
costs, explain how you arrived at your
estimate.
5. Provide specific examples to
illustrate your concerns.
6. Offer alternatives.
7. Make sure to submit your
comments by the comment period
deadline identified.
8. To ensure proper receipt by EPA,
identify the appropriate docket
identification number in the subject line
on the first page of your response. It
would also be helpful if you provided
the name, date, and Federal Register
citation related to your comments.
Abbreviations Used in This Document
AIPC All Indian Pueblo Council
ASDWA Association of State Drinking
Water Administrators
ASTM American Society for Testing
and 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 and
Prevention
CFE Combined Filter Effluent
CFR Code of Federal Regulations
COI Cost-of-Illness
CT The Residual Concentration of
Disinfectant (mg/L) Multiplied by the
Contact Time (in minutes)
CWS Community Water Systems
DAPI 4',6-Diamindino-2-phenylindole
DBFs Disinfection Byproducts
DBPR Disinfectants/Disinfection
Byproducts Rule
DE Diatomaceous Earth
DIG Differential Interference Contrast
(microscopy)
EA Economic Analysis
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EPA United States Environmental
Protection Agency
GAG Granular Activated Carbon
GWUDI Ground Water Under the
Direct Influence of Surface Water
HAAS Haloacetic acids
(Monochloroacetic, Dichloroacetic,
Trichloroacetic, Monobromoacetic
and Dibromoacetic Acids)
HPC Heterotrophic Plate Count
ICR Information Collection Request
ICRSS Information Collection Rule
Supplemental Surveys
ICRSSM Information Collection Rule
Supplemental Survey of Medium
Systems
ICRSSL Information Collection Rule
Supplemental Survey of Large
Systems
IESWTR Interim Enhanced Surface
Water Treatment Rule
IFA Immunofluorescence Assay
Log Logarithm (common, base 10)
LRAA Locational Running Annual
Average
LRV Log Removal Value
LTlESWTR Long Term 1 Enhanced
Surface Water Treatment Rule
LT2ESWTR Long Term 2 Enhanced
Surface Water Treatment Rule
MCL Maximum Contaminant Level
MCLG Maximum Contaminant Level
Goal
MGD Million Gallons per Day
M-DBP Microbial and Disinfectants/
Disinfection Byproducts
MF MicrofiUration
NCWS Non-community water systems
NF Nanofiltration
NODA Notice of Data Availability
NPDWR National Primary Drinking
Water Regulation
NTNCWS Non-transient Non-
community Water System
NTTAA National Technology Transfer
and Advancement Act
NTU Nephelometric Turbidity Unit
OMB Office of Management and
Budget
PE Performance Evaluation
PWS Public Water System
QC Quality Control
QCRV Quality Control Release Value
RAA Running Annual Average
RFA Regulatory Flexibility Act
RO Reverse Osmosis
RSD Relative Standard Deviation
SAB Science Advisory Board
SBAR Small Business Advocacy
Review
SERs Small Entity Representatives
SDWA Safe Drinking Water Act
SWTR Surface Water Treatment Rule
TCR Total Coliform Rule
TTHM Total Tribal omethanes
TNCWS Transient Non-community
Water Systems
UF Ultrafiltration
UMRA Unfunded Mandates Reform
Act
Table of Contents
1. Summary
A. Why Is EPA Proposing the LT2ESWTR?
B, What Does the LT2ESWTR Proposal
Require?
1. Treatment Requirements for
Cryptosporidium
2. Disinfection Profiling and Benchmarking
3, Uncovered Finished Water Storage
Facilities
C. Will This Proposed Regulation Apply to
My Water System?
H. Background
A. What Is the Statutory Authority for the
LT2ESWTR?
B. What Current Regulations Address
Microbial Pathogens in Drinking Water?
1. Surface Water Treatment Rule
2. Total Coliform Rule
3. Interim Enhanced Surface Water
Treatment Rule
4. Long Term 1 Enhanced Surface Water
Treatment Rule
5. Filter Backwash Recycle Rule
C. What Public Health Concerns Does This
Proposal Address?
1. Introduction
2. Cryptosporidium Health Effects and
Outbreaks
a. Health Effects
b. Waterborne Cryptosporidiosis
Outbreaks.
3. Remaining Public Health Concerns
Following the IESWTR and LTlESWTR
a. Adequacy of Physical Removal To
Control Cryptosporidium and the Need
for Risk Based Treatment Requirements.
b. Control of Cryptosporidium in
Unnhered Systems
c. Uncovered Finished Water Storage
Facilities
D. Federal Advisory Committee Process
III. New Information on Cryptosporidium
Health Risks and Treatment
A. Overview of Critical Factors for
Evaluating Regulation of Microbial
Pathogens
B. Cryptosporidium Infectivity
1, Cryptosporidium Infectivity Data
Evaluated for IESWTR
2. New Data on Cryptosporidium
Infectivity
3. Significance of New Infectivity Data
C. Cryptosporidium Occurrence
1. Occurrence Data Evaluated for IESWTR
a. Filtered Systems.
b. Unfiltered Systems
2. Overview of the Information Collection
Rule and Information Collection Rule
Supplemental Surveys (ICRSS)
a. Scope of the Information Collection Rule
b. Scope of the ICRSS
3. Analytical Methods for Protozoa in the
Information Collection Rule and ICRSS
a. Information Collection Rule Protozoan
Method
b. Method 1622 and Method 1623
4. Cryptosporidium Occurrence Results
from the Information Collection Rule and
ICRSS
a. Information Collection Rule Results
b. ICRSS Results
5. Significance of New Cryptosporidium
Occurrence Data
6. Request for Comment on Information
Collection Rule and ICRSS Data Sets
D. Treatment
1. Overview
2. Treatment Information Considered for
the IESWTR and LTlESWTR
a. Physical Removal
b. Inactivation
3. New Information on Treatment for
Control of Cryptosporidium
a. Conventional Filtration Treatment and
Direct Filtration
i. Dissolved Air Flotation.
b. Slow Sand Filtration
c. Diatomaceous Earth Filtration
d. Other Filtration Technologies
e. Inactivation
i. Ozone and Chlorine Dioxide
H. Ultraviolet Light
iii. Significance of New Information on
Inactivation
IV. Discussion of Proposed LT2ESWTR
Requirements
A. Additional Cryptosporidium Treatment
Technique Requirements for Filtered
Systems
1. What Is EPA Proposing Today?
a. Overview of Framework Approach
b. Monitoring Requirements
c. Treatment Requirements
i. Bin Classification
ii. Credit for Treatment in Place
iii. Treatment Requirements Associated
With LT2ESWTR Bins
o. Use of Previously Collected Data
2. How Was This Proposal Developed?
a. Basis for Targeted Treatment
Requirements
b. Basis for Bin Concentration Ranges and
Treatment Requirements
i. What Is the Risk Associated With a Given
Level of Cryptosporidium in a Drinking
Water Source?
ii. What Degree of Additional Treatment
Should Be Required for a Given Source
Water Cryptosporidium Level?
c. Basis for Source Water Monitoring
Requirements
i. Systems Serving at Least 10,000 People
ii. Systems Serving Fewer Than 10,000
People
iii. Future Monitoring and Reassessment
d. Basis for Accepting Previously Collected
Data
3. Request for Comment
B. Unfiltered System Treatment Technique
Requirements for Cryptosporidium
1. What Is EPA Proposing Today?
a. Overview
b. Monitoring Requirements
c. Treatment Requirements
2. How Was This Proposal Developed?
a. Basis for Cryptosporidium Treatment
Requirements
b. Basis for Requiring the Use of Two
Disinfectants
c. Basis for Source Water Monitoring
Requirements
3. Request for Comment
C. Options for Systems to Meet
Cryptosporidium Treatment
Requirements
1. Microbial Toolbox Overview
2. Watershed Control Program
a. What Is EPA Proposing Today?
b. How Was This Proposal Developed?
c. Request for Comment
3. Alternative Source
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a. What Is EPA Proposing Today?
b. How Was This Proposal Developed?
c. Request for Comment
4. Off-stream Raw Water Storage
a. What Is EPA Proposing Today?
b. How Was This Proposal Developed?
c. Request for Comment
5. Pre-sedimentation With Coagulant
a. What Is EPA Proposing Today?
b. How Was This Proposal Developed?
i. Published Studies of Cryptosporidium
Removal by Conventional Sedimentation
Basins
ii. Data Supplied by Utilities on the
Removal of Spores by Presedimentation
c. Request for Comment
6. Bank Filtration
a. What Is EPA Proposing Today?
b. How Was This Proposal Developed?
c. Request for Comment
7. Lime Softening
a. What Is EPA Proposing Today?
b. How Was This Proposal Developed?
c. Request for Comment
8. Combined Filter Performance
a. What Is EPA Proposing Today?
b. How Was This Proposal Developed?
c. Request for Comment
9. Roughing Filter
a. What Is EPA Proposing Today?
b. How Was This Proposal Developed?
c. Request for Comment
10. Slow Sand Filtration
a. What Is EPA Proposing Today?
b. How Was This Proposal Developed?
c. Request for Comment
11. Membrane Filtration
a. What Is EPA Proposing Today?
b. How Was This Proposal Developed?
c. Request for Comment
12. Bag and Cartridge Filtration
a. What Is EPA Proposing Today?
b. How Was This Proposal Developed?
c. Request for Comment
13. Secondary Filtration
a. What Is EPA Proposing Today?
b. How Was This Proposal Developed?
c. Request for Comment
14. Ozone and Chlorine Dioxide
a. What Is EPA Proposing Today?
b. How Was This Proposal Developed?
c. Request for Comments
15. Ultraviolet Light
a. What Is EPA Proposing Today?
b. How Was This Proposal Developed?
c. Request for Comment
16. Individual Filter Performance
a. What Is EPA Proposing Today?
b. How Was This Proposal Developed?
c. Request for Comment
17. Other Demonstration of Performance
a. What Is EPA Proposing Today?
b. How Was This Proposal Developed?
c. Request for Comment
D. Disinfection Benchmarks for Giardia
lambHa and Viruses
1. What Is EPA Proposing Today?
a. Applicability and Schedule
b. Developing the Disinfection Profile and
Benchmark
c. State Review
2. How Was This Proposal Developed?
3. Request for Comments
E. Additional Treatment Technique
Requirements for Systems with
Uncovered Finished Water Storage
Facilities
1. What Is EPA Proposing Today?
2. How Was This Proposal Developed?
3. Request for Comments
F. Compliance Schedules
1. What Is EPA Proposing Today?
a. Source Water Monitoring
i. Filtered Systems
ii. Unfiltered Systems
b. Treatment Requirements
c. Disinfection Benchmarks for Giardia
lamblia and Viruses
2. How Was This Proposal Developed?
3. Request for Comments
G. Public Notice Requirements
1. What Is EPA Proposing Today?
2. How Was This Proposal Developed?
3. Request for Comment
H, Variances and Exemptions
1. Variances
2. Exemptions
3. Request for Comment
a. Variances
b. Exemptions
I. Requirements for Systems To Use
Qualified Operators
J. System Reporting and Recordkeeping
Requirements
1. Overview
2. Reporting Requirements for Source
Water Monitoring -
a. Data Elements To Be Reported
b. Data System
c. Previously Collected Monitoring Data
3. Compliance With Additional Treatment
Requirements
4. Request for Comment
K. Analytical Methods
1. Cryptosporidium
a. What Is EPA Proposing Today?
b. How Was This Proposal Developed?
c. Request for Comment
2. E. coif
a. What Is EPA Proposing Today?
b. How Was This Proposal Developed?
c. Request for Comment
3. Turbidity
a. What Is EPA Proposing Today?
b. How Was This Proposal Developed?
c. Request for Comment
L. Laboratory Approval
1. Cryptosporidium Laboratory Approval
2. E. coli Laboratory Approval
3. Turbidity Analyst Approval
4. Request for Comment
M. Requirements for Sanitary Surveys
Conducted by EPA
1. Overview
2. Background
3. Request for Comment
V. State Implementation
A. Special State Primacy Requirements
B. State Recordkeeping Requirements
C. State Reporting Requirements
D. Interim Primacy
VI. Economic Analysis
A. What Regulatory Alternatives Did the
Agency Consider?
B. What Analyses Support Selecting the
Proposed Rule Option?
C. What Are the Benefits of the Proposed
LT2ESWTR?
1. Non-quantifiable Health and Non-health
Related Benefits
2. Quantifiable Health Benefits
a. Filtered Systems
b. Unfiltered Systems
3, Timing of Benefits Accrual (latency)
D. What Are the Costs of the Proposed
LT2ESWTR?
1. Total Annualized Present Value Costs
2. Water System Costs
a. Source Water Monitoring Costs
b. Filtered Systems Treatment Costs
c. Unfiltered Systems Treatment Costs
d. Uncovered Finished Water Storage
Facilities
e. Future Monitoring Costs
f. Sensitivity Analysis-influent Bromide
Levels on Technology Selection for
Filtered Plants
3. State/Primacy Agency Costs
4. Non-quantified Costs
E. What Are the Household Costs of the
Proposed Rule?
F. What Are the Incremental Costs and
Benefits of the Proposed LT2ESWTR?
G. Are There Benefits From the Reduction
of Co-occurring Contaminants?
H. Are There Increased Risks From Other
Contaminants?
I. What Are the Effects of the Contaminant
on the General Population and Groups
Within the General Populations That Are
Identified as Likely to be at Greater Risk
of Adverse Health Effects?
J. What Are the Uncertainties in the
Baseline, Risk, Benefit, and Cost
Estimates for the Proposed LT2ESWTR
as well as the Quality and Extent of the
Information?
K. What Is the Benefit/Cost Determination
for the Proposed LT2ESWTR?
L. Request for Comment
VII. Statutory and Executive Order Reviews
A. Executive Order 12866: Regulatory
Planning and Review
B. Paperwork Reduction Act
C. Regulatory Flexibility Act
D. 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 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
E. Executive Order 13132: Federalism
F. Executive Order 13175: Consultation
and Coordination With Indian Tribal
Governments
G. Executive Order 13045: Protection of
Children from Environmental Health and
Safety Risks
H. Executive Order 13211: Actions that
Significantly Affect Energy Supply,
Distribution, or Use
I. National Technology Transfer and
Advancement Act
J. Executive Order 12898: Federal Actions
to Address Environmental Justice in
Minority Populations or Low-Income
Populations
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K. Consultations With the Science
Advisory Board, National Drinking
Water Advisory Council, and the
Secretary of Health and Human Services
L. Plain Language
Vlll. References
I. Summary
A. Why Is EPA Proposing the
LT2ESWTR?
EPA is proposing the Long Term 2
Enhanced Surface Water Treatment Rule
(LT2ESWTR) to provide for increased
protection against microbial pathogens
in public water systems that use surface
water sources. The proposed
LT2ESWTR focuses on
Cryptosporidium, which is a protozoan
pathogen that is widespread in surface
water. EPA is particularly concerned
about Cryptosporidium because it is
highly resistant to inactivation by
standard disinfection practices like
chlorination. Ingestion of
Cryptosporidium oocysts can cause
acute gastrointestinal illness, and health
effects in sensitive subpopulations may
be severe, including risk of mortality.
Cryptosporidium has been identified as
the pathogenic agent in a number of
waterborne disease outbreaks across the
U.S. and in Canada (details in section
II).
The intent of the LT2ESWTR is to
supplement existing microbial treatment
requirements for systems where
additional public health protection is
needed. Currently, the Interim
Enhanced Surface Water Treatment Rule
(IESWTR) requires large systems that
filter to remove at least 99% (2 log) of
Cryptosporidium (63 FR 69478,
December 16,1998) (USEPA 1998a).
The Long Term 1 Enhanced Surface
Water Treatment Rule (LT1ESWTR)
extends this requirement to small
systems (67 FR 1812, January 14, 2002)
(USEPA 2002a). Subsequent to
promulgating these regulations, EPA has
evaluated significant new data on
Cryptosporidium infectivity,
occurrence, and treatment (details in
section HI). These data indicate that
current treatment requirements achieve
adequate protection for the majority of
systems, but there is a subset of systems
with higher vulnerability to
Cryptosporidium where additional
treatment is necessary.
Specifically, national survey data
show that average Cryptosporidium
occurrence in filtered systems is lower
than previously estimated. However,
these data also demonstrate that
Cryptosporidium concentrations vary
widely among systems, and that a
fraction of filtered systems have
relatively high levels of source water
Cryptosporidium contamination. Based
on this finding, along with new data
suggesting that the infectivity (i.e.,
virulence) of Cryptosporidium may be
substantially higher than previously
understood, EPA has concluded that the
current 2 log removal requirement does
not provide an adequate degree of
treatment in filtered systems with the
highest source water Cryptosporidium
levels. Consequently, EPA is proposing
targeted additional treatment
requirements under the LT2ESWTR for
filtered systems with the highest
Cryptosporidium risk.
Under current regulations, unfiltered
systems are not required to provide any
treatment for Cryptosporidium. New
occurrence data suggest that typical
Cryptosporidium levels in the treated
water of unfiltered systems are
substantially higher than in the treated
water of filtered systems. Hence,
Cryptosporidium treatment by
unfiltered systems is needed to achieve
equivalent public health protection.
Recent treatment studies have allowed
EPA to develop criteria for systems to
inactivate Cryptosporidium with ozone,
ultraviolet (UV) light, and chlorine
dioxide. As a result, EPA has concluded
that it is feasible and appropriate to
propose under the LT2ESWTR that all
unfiltered systems treat for
Cryptosporidium.
In addition to concern with
Cryptosporidium, the LT2ESWTR
proposal is intended to ensure that
systems maintain adequate protection
against microbial pathogens as they take
steps to reduce formation of disinfection
byproducts (DBFs). Along with the
LT2ESWTR, EPA is also developing a
Stage 2 Disinfection Byproducts Rule
(DBPR), which will further limit
allowable levels of trihalomethanes and
haloacetic acids. The proposed
LT2ESWTR contains disinfection
profiling and benchmarking
requirements to ensure that microbial
protection is maintained as systems
comply with the Stage 2 DBPR. Also in
the proposed LT2ESWTR are
requirements to limit risk associated
with existing uncovered finished water
storage facilities. Uncovered storage
facilities are subject to contamination if
not properly managed or treated.
Today's proposed LT2ESWTR reflects
consensus recommendations from the
Stage 2 Microbial and Disinfection
Byproducts (M-DBP) Federal Advisory
Committee. These recommendations are
set forth in the Stage 2 M-DBP
Agreement in Principle (65 FR 83015,
December 29, 2000} (USEPA 2000a).
B. What Does the LT2ESWTH Proposal
Require?
1. Treatment Requirements for
Cryptosporidium
EPA is proposing risk-targeted
treatment technique requirements for
Cryptosporidium control in filtered
systems that are based on a microbial
framework approach. Under this
approach, systems that use a surface
water or ground water under the direct
influence of surface water (referred to
collectively as surface water systems)
will conduct source water monitoring to
determine an average Cryptosporidium
concentration. Based on monitoring
results, filtered systems will be
classified in one of four possible risk
categories (bins). A filtered system's bin
classification determines the extent of
any additional Cryptosporidium
treatment requirements beyond the
requirements of current regulations.
EPA expects that the majority of
filtered systems will be classified in the
Bin 1, which carries no additional
treatment requirements. Those systems
classified Bins 2-4 will be required to
provide from 1.0 to 2.5 log of treatment
(i.e., 90 to 99.7 percent reduction) for
Cryptosporidium in addition to
conventional treatment that complies
with the 1ESWTR or LT1ESWTR (details
in section IV.A). Filtered systems will
meet additional Cryptosporidium
treatment requirements by using one or
more treatment or control steps from a
"microbial toolbox" of options (details
in section IV.C). Rather than monitoring,
filtered systems may elect to comply
with the treatment requirements of Bin
4 directly.
Under the proposed LT2ESWTR, all
surface water systems that are not
required to filter (i.e., unfiltered
systems) must provide at least 2 log (i.e.,
99 percent) inactivation of
Cryptosporidium. In addition, unfiltered
systems will monitor for
Cryptosporidium in their source water
and must achieve at least 3 log (i.e., 99.9
percent) inactivation of
Cryptosporidium if the mean level
exceeds 0.01 oocysts/L. Alternatively,
unfiltered systems may elect to provide
3 log Cryptosporidium inactivation
directly, instead of moriitoring. All
requirements established under the
Surface Water Treatment Rule (SWTR)
(54 FR 27486, June 29, 1989) (USEPA
1989a) for unfiltered systems will
remain in effect, including 3 log
inactivation of Giardia lamblia and 4 log
inactivation of viruses. However, the
LT2ESWTR proposal requires that
unfiltered systems achieve their overall
inactivation requirements using a
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47645
minimum of two disinfectants (details
in section IV.B).
2. Disinfection Profiling and
Benchmarking
The purpose of disinfection profiling
and benchmarking is to ensure that
when a system makes a significant
change to its disinfection practice, it
does not compromise the adequacy of
existing microbial protection. EPA
established the disinfection benchmark
under the IESWTR and LTlESWTR for
the Stage 1 M-DBP rules, and the
LT2ESWTR proposal extends
disinfection benchmark requirements to
apply to the Stage 2 M-DBP rules.
The proposed profiling and
benchmarking requirements are similar
to those promulgated under IESWTR
and LTlESWTR. Systems that meet
specified criteria must prepare
disinfection profiles that characterize
current levels of virus and Giardia
lamblia inactivation over the course of
one year. Systems with valid
operational data from profiling
conducted under the IESWTR or
LTlESWTR are not required to collect
additional data. If a system that is
required to prepare a profile proposes to
make a significant change to its
disinfection practice, the system must
calculate a disinfection benchmark and
must consult with the State regarding
how the proposed change will affect the
current benchmark (details in section
IV.D).
3. Uncovered Finished Water Storage
Facilities
The proposed LT2ESWTR also
includes requirements for systems with
uncovered finished water storage
facilities. The IESWTR and LTlESWTR
require systems to cover all new storage
facilities for finished water, but these
rules do not address existing uncovered
finished water storage facilities. Under
the LT2ESWTR proposal, systems with
uncovered finished water storage
facilities must cover the storage facility
or treat the storage facility discharge to
achieve 4 log virus inactivation unless
the State determines that existing risk
mitigation is adequate. Where the State
makes such a determination, systems
must develop and implement a risk
mitigation plan that addresses physical
access, surface water run-off, animal
and bird wastes, and on-going water
quality assessment (details in section
IV.E).
C. Will This Proposed Regulation Apply
to My Water System?
All community and non-community
water systems that use surface water or
ground water under the direct influence
of surface water are affected by the
proposed LT2ESWTR.
II. Background
A. What Is the Statutory Authority for
the LT2ESWTR?
This section discusses the Safe
Drinking Water Act (SDWA or the Act)
sections that direct the development of
the LT2ESWTR.
The Act, as amended in 1996, requires'
EPA to publish a maximum
contaminant level goal (MCLG) and ,
promulgate a national primary drinking
water regulation (NPDWR) with
enforceable requirements for any
contaminant that the Administrator
determines may have an adverse effect
on the health of persons, is known to
occur or there is a substantial likelihood
that the contaminant will occur in
public water systems (PWSs) 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 PWSs
(section 1412 (b)(l)(A)).
MCLGs are non-enforceable health
goals, and 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 (sections 1412(b)(4) and
1412(a)(3)). EPA established an MCLG
of zero for Cryptosporidium under the
IESWTR (63 FR 69478, December 16,
1998) (USEPA 1998a). The Agency is
not proposing any changes to the
current MCLG for Cryptosporidium.
The Act also requires that at the same
time EPA publishes an NPDWR and
MCLG, it must specify in the NPDWR a
maximum contaminant level (MCL)
which is as close to the MCLG as is
feasible (sections 1412(b)(4) and
1401(l)(c)). The Agency is authorized to
promulgate an 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 (sections
1412(b)(7)(A) and 1401(1)(Q). The Act
specifies that in such cases, the Agency
shall identify those treatment
techniques that would prevent known
or anticipated adverse effects on the
health of persons to the extent feasible
(section 1412(b)(7)(A)).
The Agency has concluded that it is
not currently economically or
technologically feasible for PWSs to
determine the level of Cryptosporidium
in finished drinking water for the
purpose of compliance with a finished
water standard (the performance of
available analytical methods for
Cryptosporidium is described in section
III.C; the treated water Cryptosporidium
levels that the LT2ESWTR will achieve
are described in section IV.A).
Consequently, today's proposal for the
LT2ESWTR relies on treatment
technique requirements to reduce health
risks from Cryptosporidium in PWSs.
When proposing a NPDWR that
includes an MCL or treatment
technique, the Act requires EPA to
publish and seek public comment on an
analysis of health risk reduction and
cost impacts. This includes an analysis
of quantifiable and non quantifiable
costs and health risk reduction benefits,
incremental costs and benefits of each
alternative considered, the effects of the
contaminant upon sensitive
subpopulations (e.g., infants, children,
pregnant women, the elderly, and
individuals with a history of serious
illness), any increased risk that may
occur as the result of compliance, and
other relevant factors (section 1412
(b)(3)(C)). EPA's analysis of health
benefits and costs associated with the
proposed LT2ESWTR is presented in
"Economic Analysis of the LT2ESWTR"
(USEPA 2003a) and is summarized in
section VI of this preamble. However,
the Act does not authorize the
Administrator to use additional health
risk reduction and cost considerations
to establish MCL or treatment technique
requirements for the control of
Cryptosporidium (section 1412
Finally, section 1412 (b)(2)(C) of
SDWA requires EPA to promulgate a
Stage 2 Disinfectants and Disinfection
Byproducts Rule within 18 months after
promulgation of the LTlESWTR, which
occurred on January 14, 2002.
Consistent with statutory requirements
for risk balancing (section
1412(b)(5)(B)), EPA will finalize the
LT2ESWTR with the Stage 2 DBPR to
ensure parallel protection from
microbial and DBF risks.
B. What Current Regulations Address
Microbial Pathogens in Drinking Water?
This section summarizes the existing
regulations that apply to control of
pathogenic microorganisms in surface
water systems. These rules form the
baseline of regulatory protection that
will be supplemented by the
LT2ESWTR.
1. Surface Water Treatment Rule
The SWTR (54 FR 27486, June 29,
1989) (USEPA 1989a) applies to all
PWSs using surface water or ground
water under the direct influence
(GWUDI) of surface water as sources
(Subpart H systems). It established
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MCLGs of zero for Giardia lamblia,
viruses, and Legionella, and includes
treatment technique requirements to
reduce exposure to pathogenic
microorganisms, including: (1)
Filtration, unless specified avoidance
criteria are met; (2) maintenance of a
disinfectant residual in the distribution
system; (3) removal and/or inactivation
of 3 log (99.9%) of Giardia lamblia and
4 log (99.99%) of viruses; (4) combined
filter effluent turbidity of 5
nephelometric turbidity units (NTU) as
a maximum and 0,5 NTU at 95th
percentile monthly for treatment plants
using conventional treatment or direct
filtration (with separate standards for
other filtration technologies); and (5)
watershed protection and source water
quality requirements for unfiltered
systems.
2. Total Coliform Rule
The Total Coliform Rule (TCR) (54 FR
27544, June 29, 1989) (USEPA 1989b)
applies to all PWSs. It established an
MCLG of zero for total and fecal
coliform bacteria, and an MCL based on
the percentage of positive samples
collected during a compliance period.
Coliforms are used as a screen for fecal
contamination and to determine the
integrity of the water treatment process
and distribution system. Under the TCR,
no more than 5 percent of distribution
system samples collected in any month
may contain coliform bacteria (no more
than 1 sample per month may be
coliform positive in those systems that
collect fewer than 40 samples per
month). The number of samples to be
collected in a month is based on the
number of people served by the system,
3. Interim Enhanced Surface Water
Treatment Rule
The IESWTR (63 FR 69477, December
16, 1998) (USEPA 1998a) applies to
PWSs serving at least 10,000 people and
using surface water or GWUDI sources.
Key provisions established by the
IESWTR include the following: (1) An
MCLG of zero for Cryptosporidium; (2)
Cryptosporidium removal requirements
of 2 log (99 percent) for systems that
filter; (3) strengthened combined filter
effluent turbidity performance standards
of 1.0 NTU as a maximum and 0.3 NTU
at the 95th percentile monthly for
treatment plants using conventional
treatment or direct filtration; (4)
requirements for individual filter
turbidity monitoring; (5) disinfection
benchmark provisions to assess the level
of microbial protection provided as
facilities take steps to comply with new
DBF standards; (6) inclusion of
Cryptosporidium in the definition of
GWUDI and in the watershed control
requirements for unfiltered public water
systems; (7) requirements for covers on
new finished water storage facilities;
and (8) sanitary surveys for all surface
water systems regardless of size.
The IESWTR was developed in
conjunction with the Stage 1
Disinfectants and Disinfection
Byproducts Rule (Stage 1 DBPR) (63 FR
69389; December 16,1998) (USEPA
1998b), which reduced allowable levels
of certain DBFs, including
trihalomethanes, haloacetic acids,
chlorite, and bromate.
4. Long Term 1 Enhanced Surface Water
Treatment Rule
The LT1ESWTR (67 FR 1812, January
14, 2002) (USEPA 2002a) builds upon
the microbial control provisions
established by the IESWTR for large
systems, through extending similar
requirements to small systems. The
LT1ESWTR applies to PWSs using
surface water or GWUDI as sources that
serve fewer than 10,000 people. Like the
IESWTR, the LTlESWTR established
the following: 2 log (99 percent)
Cryptosporidium removal requirements
for systems that filter; individual filter
turbidity monitoring and more stringent
combined filter effluent turbidity
standards for conventional and direct
filtration plants; disinfection profiling
and benchmarking; inclusion of
Cryptosporidium in the definition of
GWUDI and in the watershed control
requirements for unfiltered systems; and
the requirement that new finished water
storage facilities be covered.
5. Filter Backwash Recycle Rule
EPA promulgated the Filter Backwash
Recycling Rule (FBRR) (66 FR 31085,
June 8, 2001} (USEPA 2001a) to increase
protection of finished drinking water
supplies from contamination by
Cryptosporidium and other microbial
pathogens. The FBRR requirements will
reduce the potential risks associated
with recycling contaminants removed
during the filtration process. The FBRR
provisions apply to all systems that
recycle, regardless of population served.
In general, the provisions include the
following: (1) Recycling systems must
return certain recycle streams prior to
the point of primary coagulant addition
unless the State specifies an alternative
location; (2) direct filtration systems
recycling to the treatment process must
provide detailed recycle treatment
information to the State; and (3) certain
conventional systems that practice
direct recycling must perform a one-
month, one-time recycling self
assessment.
C. What Public Health Concerns Does
This Proposal Address?
This section presents the basis for the
public health concern associated with
Cryptosporidium in drinking water by
summarizing information on
Cryptosporidium health effects and
outbreaks. This is followed by a
description of the specific areas of
public health concern that remain after
implementation of the IESWTR and
LTlESWTR and that are addressed in
the LT2ESWTR proposal. More detailed
information about Cryptosporidium
health effects may be found in the
following criteria documents:
Cryptosporidium: Human Health
Criteria Document (USEPA 2001b),
Cryptosporidium: Drinking Water
Advisory (USEPA 2001c), and
Cryptospondium: Risks for Infants and
Children (USEPA 2001 d).
1. Introduction
While modern water treatment
systems have substantially reduced
waterborne disease incidence, drinking
water contamination remains a
significant health risk management
challenge. EPA's Science Advisory
Board in 1990 cited drinking water
contamination, particularly
contamination by pathogenic
microorganisms, as one of the most
important environmental risks (USEPA
1990). This risk is underscored by
information from the Centers for Disease
Control and Prevention (CDC) which
indicates that between 1980 and 1998 a
total of 419 outbreaks associated with
drinking water were reported, with
greater than 511,000 estimated cases of
disease. A number of agents were
implicated in these outbreaks, including
viruses, bacteria, and protozoa, as well
as several chemicals (Craun and
Calderon 1996, Levy et al 1998,
Barwick et al, 2000). The majority of
cases were associated with surface
water, and specifically with the 1993
Cryptosporidium outbreak in
Milwaukee, WI with an estimated
403,000 cases (Mac Kenzie et al. 1994).
A recent study by McDonald et al
(2001), which used blood samples from
Milwaukee children collected during
and after the 1993 outbreak, suggests
that Cryptosporidium infection,
including asymptomatic infection, was
more widespread than might be inferred
from the illness estimates by Mac
Kenzie etal. (1994).
It is important to note that the number
of identified and reported outbreaks in
the CDC database is believed to
substantially understate the actual
incidence of waterborne disease
outbreaks and cases (Craun and
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47647
Calderon 1996, National Research
Council 1997). This under reporting is
due to a number of factors. Many people
experiencing gastrointestinal illness do
not seek medical attention. Where
medical attention is provided, the
pathogenic agent may not be identified
through routine testing. Physicians often
lack sufficient information to attribute
gastrointestinal illness to any specific
origin, such as drinking water, and few
States have an active outbreak
surveillance program. Consequently,
outbreaks are often not recognized in a
community or, if recognized, are not
traced to a drinking water source.
In addition, an unknown but probably
significant portion of waterborne
disease is endemic (i.e. isolated cases
not associated with an outbreak) and,
thus, is even more difficult to recognize.
The Economic Analysis for the
proposed LT2ESWTR (USEPA 2003a)
uses data on Cryptosporidium
occurrence, infectivity, and treatment to
estimate the baseline endemic incidence
of cryptosporidiosis attributable to
drinking water, as well as the reductions
projected as a result of this rule.
Most waterborne pathogens cause
gastrointestinal illness with diarrhea,
abdominal discomfort, nausea,
vomiting, and other symptoms. The
effects of waterborne disease are usually
acute, resulting from a single or small
number of exposures. Such illnesses are
generally of short duration in healthy
people. However, some pathogens,
including Giardia lamblia and
Cryptosporidium, may cause disease
lasting weeks or longer in otherwise
healthy individuals, though this is not
typical for Cryptosporidium.
Waterborne pathogens also cause more
serious disorders such as hepatitis,
peptic ulcers, myocarditis, paralysis,
conjunctivitis, swollen lymph glands,
meningitis, and reactive arthritis, and
have been associated with diabetes,
encephalitis, and other diseases
(Lederberg 1992).
There are populations that are at
greater risk from waterborne disease.
These sensitive subpopulations include
children (especially infants), the elderly,
the malnourished, pregnant women, the
disease impaired (e.g., diabetes, cystic
fibrosis), and a broad category of those
with compromised immune systems,
such as AIDS patients, those with
autoimmune disorders (e.g., rheumatoid
arthritis, lupus erythematosus, multiple
sclerosis), transplant recipients, and
those on chemotherapy (Rose 1997).
This sensitive segment represents
almost 20% of the population in the
United States (Gerba et al. 1996). The
severity and duration of illness is often
greater in sensitive subpopulations than
in healthy individuals, and in a small
percentage of such cases, death may
result.
2. Cryptosporidium Health Effects and
Outbreaks
Cryptosporidium is a protozoan
parasite that exists in warm-blooded
hosts and, upon excretion, may survive
for months in the environment (Kato et
al., 2001). Ingestion of Cryptosporidium
can lead to cryptosporidiosis, a
gastrointestinal illness. Transmission of
cryptosporidiosis often occurs through
consumption of feces contaminated food
or water, but may also result from direct
or indirect contact with infected persons
or animals (Casemore 1990). Surveys
(described in Section III) indicate that
Cryptosporidium is common in surface
waters used as drinking water supplies.
Sources of Cryptosporidium
contamination include animal
agriculture, wastewater treatment plant
discharges, slaughterhouses, birds, wild
animals, and other sources of fecal
matter.
EPA is particularly concerned about
Cryptosporidium because, unlike
pathogens such as bacteria and most
viruses, Cryptosporidium oocysts are
highly resistant to standard
disinfectants like chlorine and
chloramines. Consequently, control of
Cryptosporidium in most treatment
plants is dependent on physical removal
processes. Finished water monitoring
data indicate that Cryptosporidium is
sometimes present in filtered, treated
drinking water (LeChevallier ef al. 1991;
Aboytes et al. 2002). Moreover, as noted
later, many of the individuals sickened
by waterborne outbreaks of
cryptosporidiosis were served by
filtered surface water supplies (Solo-
Gabriele and Neumeister, 1996). In some
cases, these outbreaks were attributed to
treatment deficiencies, while in other
cases the cause was unidentified (see
Table II-l).
These data suggest that surface water
systems that filter and disinfect may
still be vulnerable to Cryptosporidium,
depending on the source water quality
and treatment effectiveness. Today's
proposed rule addresses concern with
passage of Cryptosporidium through
physical removal processes during
water treatment, as well as in systems
lacking filtration.
a. Health effects. Cryptosporidium
infection is characterized by mild to
severe diarrhea, dehydration, stomach
cramps, and/or a slight fever. Symptoms
typically last from several days to two
weeks, though in a small percentage of
cases, the symptoms may persist for
months or longer in otherwise healthy
individuals. Human feeding studies
have demonstrated that a low dose of
Cryptosporidium parvum (C. parvum) is
sufficient to cause infection in healthy
adults (DuPont et a!. 1995, Chappell et
al. 1999, Messner et al. 2001). Studies
of immunosuppressed adult mice have
demonstrated that a single viable oocyst
can induce patent C. parvum infections
(Yang et al. 2000).
There is evidence that an immune
response to Cryptosporidium exists, but
the degree and duration of this
immunity is not well characterized. In
a study by Chappell et al. (1999),
individuals with a blood serum
antibody (IgG), which can develop from
exposure to C. parvum, demonstrated
immunity to low doses of oocysts. The
investigators found the ID50 dose (i.e.,
dose that infects 50% of the challenged
population) of one C. parvum isolate for
adult volunteers who had pre-existing
serum IgG to be 1,880 oocysts in
comparison to 132 oocysts for
individuals reported as serologically
negative. However, the implications of
these data for studies of
Cryptosporidium infectivity are unclear.
Earlier work did not observe a
correlation between the development of
antibodies after Cryptosporidium
exposure and subsequent protection
from illness (Okhuysen et al. 1998}. A
subsequent investigation by Muller et
al. (2001) observed serological
responses to Cryptosporidium antigens
in samples from individuals reported by
Chappel et al. as serologically negative.
Cryptosporidium parvum was first
recognized as a human pathogen in
1976 (Juranek 1995). Cases of illness
from Cryptosporidium were rarely
reported until 1982 when documented
disease incidence increased due to the
AIDS epidemic (Current 1983). As
laboratory diagnostic techniques
improved during subsequent years,
outbreaks among immunocompetent
persons were recognized as well.
Human, cattle, dog and deer types of C.
parvum have been found in healthy
individuals (Ong et al. 2002, Morgan-
Ryan et al. 2002). Other
Cryptosporidium species (C. felis, C.
meleagridis, and possibly C. muris) have
infected healthy individuals, primarily
children (Xiao et al. 2001, Chalmers et
al. 2002, Katsumata et al 2000). Cross-
species infection occurs. The human
type of C. parvum (now named C.
hominis (Morgan-Ryan et al. 2002)) has
infected a dugong and monkeys (Spano
et al. 1998). The cattle type of C. parvum
infects humans, wild animals, and other
livestock, such as sheep, goats and deer
(Ong et al. 2002).
As noted earlier, there are sensitive
populations that are at greater risk from
pathogenic microorganisms.
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Cryptosporidiosis symptoms in
immunocompromised subpopulations
are much more severe, including
debilitating voluminous diarrhea that
may be accompanied by severe
abdominal cramps, weight loss, and low
grade fever (Juranek 1995). Mortality is
a significant threat to the
immunocompromised infected with
Cryptosporidium:
the duration and severity of the disease are
significant: whereas 1 percent of the
immunocompetent population may be
hospitalized with very little risk of mortality,
Cryptosporidium infections are associated
with a high rate of mortality in the
immunocompromised (Rose 1997)
A follow-up study of the 1993
Milwaukee, WI outbreak reported that at
least 50 Cryp(osporich'um-associated
deaths occurred among the severely
immunocompromised (Hoxie et al.
1997).
b. Waterborne cryptosporidiosis
outbreaks. Cryptosporidium has caused
a number of waterborne disease
outbreaks since 1984 when the first one
was reported in the U.S. Table 11-1 lists
reported outbreaks in community water
systems (CWS) and non-community
water systems (NCWS). Between 1984—
1998, nine outbreaks caused by
Cryptosporidium were reported in the-
U.S. with approximately 421,000 cases
associated cases of illness (CDC 1993,
1996,1998, 2000, and 2001), Solo-
Gabriele and Neumeister (1996)
characterized water supplies associated
with U.S. outbreaks of
cryptosporidiosis. They determined that
almost half of the outbreaks were
associated with ground water (untreated
or chlorinated springs and wells), but
that the majority of affected individuals
were served by filtered surface water
supplies (rivers and lakes). They found
that during outbreaks involving treated
spring or well water, the chlorination
systems were apparently operating
satisfactorily, with a measurable
chlorine residual.
Although the occurrence of
Cryptosporidium in U.S. drinking water
supplies has been substantiated by data
collected during outbreak
investigations, the source and density of
oocysts associated with the outbreak
have not always been detected or
reported. Furthermore, because of
limitations and uncertainties of the
immunofluorescence assay (IFA)
method used in earlier studies, negative
results in source or finished water
during these outbreaks do not
necessarily mean tbat there were no
oocysts in the water at the time of
sampling.
TABLE 11-1.—OUTBREAKS CAUSED BY Cryptosporidium IN PUBLIC WATER SYSTEMS: 1984-1998
Year
1984
1987
1991
1992
1992
1993
1993
1994
1998
State
TX
GA
PA
OR
OR
NV
WI
WA
TX
Cases
117
13,000
551
tt
ft
103
403,000
134
1,400
System
CWS
CWS
NCWS
CWS
CWS
CWS
CWS
CWS
CWS
Deficiency
3
3
3
3
3
5
3
2
3
Source
Well.
River.
Welt.
Spring.
River.
Lake.
Lake.
Well.
Well.
ft=Total estimated cases were 3,000. The locations were nearby and cases overlapped in time Definitions of deficiencies = (1) untreated sur-
face water; (2) untreated ground water; (3) treatment deficiency (e.g., temporary interruption of disinfection, chronically inadequate disinfection,
and inadequate or no filtration); (4) distribution system deficiency (e.g., cross connection, contamination of water mains during construction or re-
pair, and contamination of a storage facility); and (5) unknown or miscellaneous deficiency.
3. Remaining Public Health Concerns
Following the IESWTR and LTlESWTR
This section presents the areas of
remaining public health concern
following implementation of the
IESWTR and LTlESWTR that EPA
proposes to address in the LT2ESWTR.
These are as follows: (a) Adequacy of
physical removal to control
Cryptosporidium and the need for risk
based treatment requirements; (b)
control of Cryptosporidium in unfiltered
systems; and (c) uncovered finished
water storage facilities.
EPA recognized each of these issues
as a potential public health concern
during development of the IESWTR, but
could not address them at that time due
to the absence of key data. Accordingly,
this section begins with a description of
how EPA considered these issues during
development of the IESWTR, including
the data gaps that were identified at that
time. This is followed by a statement of
the extent to which new information has
filled these data gaps, thereby allowing
EPA to address these public health
concerns in the LT2ESWTR proposal.
a. Adequacy of physical removal to
control Cryptosporidium and the need
for risk based treatment requirements. A
question that received significant
consideration during development of
the IESWTR is whether physical
removal by filtration plants provides
adequate protection against
Cryptosporidium in drinking water, or
whether certain systems should be
required to provide inactivation of
Cryptosporidium based on source water
pathogen levels. As discussed in the
proposal, notice of data availability
(NODA), and final IESWTR, EPA and
stakeholders concluded that data
available during IESWTR development
were not adequate to support risk based
inactivation requirements for
Cryptosporidium. However, the Agency
maintained that a risk based approach to
Cryptosporidium control would be
considered for the LT2ESWTR when
data collected under the Information
Collection Rule were available and other
critical information needs had been
addressed.
The IESWTR proposal (59 FR 38832,
July 29,1994) (USEPA 1994) included
two treatment alternatives, labeled B
and C, that specifically addressed
Cryptosporidium. Under Alternative B,
the level of required treatment would be
based on the density of
Cryptosporidium in the source water.
The proposal noted concerns with this
approach, though, due to uncertainty in
the risk associated with
Cryptosporidium and the feasibility of
achieving higher treatment levels
through disinfection. Consequently,
EPA also proposed Alternative C, which
would require 2 log (99%) removal of
Cryptosporidium by filtration. This was
based on the determination that 2 log
Cryptosporidium removal is feasible
using conventional treatment.
In the 1996 Information Collection
Rule (61 FR 24354, May 14,1996)
(USEPA 1996a), EPA concluded that the
analytical method prescribed for
measuring Cryptosporidium was
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adequate for making national
occurrence estimates, but would not
suffice for making site specific source
water density estimates. This finding
further contributed to the rationale
supporting Alternative C under the
proposed IESWTR.
The NODA for the IESWTR (62 FR
59498, Nov. 3, 1997) (USEPA 1997a)
presented the recommendations of the
Stage 1 MDBP Federal Advisory
Committee for the IESWTR. As stated in
the NODA, the Committee engaged in
. extensive discussions regarding the
adequacy of relying solely on physical
removal to control Cryptosporidium and
the need for inactivation. There was an
absence of consensus on whether it was
possible at that time to adequately
measure Cryptosporidium inactivation
efficiencies for various disinfection
technologies. This was a significant
impediment to addressing inactivation
in the IESWTR. However, the
Committee recognized that inactivation
requirements may be necessary under
future regulatory scenarios, as shown by
the following consensus
recommendation from the Stage 1
MDBP Agreement in Principle:
EPA should issue a risk based proposal of
the Final Enhanced Surface Water Treatment
Rule for Cryptosporidium embodying the
multiple barrier approach (e.g., source water
protection, physical removal, inactivation,
etc.), including, where risks suggest
appropriate, inactivation requirements (62 FR
59557, Nov. 3,1997) (USEPA 1997a).
The preamble to the final IESWTR (63
FR 69478, Dec. 16,1998) (USEPA
1998a) states that EPA was unable to
consider the proposed Alternative B
(treatment requirements for
Cryptosporidium based on source water
occurrence levels) for the IESWTR
because occurrence data from the
Information Collection Rule survey and
related analysis were not available in
time to meet the statutory promulgation
deadline. The Agency affirmed, though,
that further control of Cryptosporidium
would be addressed in the LT2ESWTR.
In today's notice, EPA is proposing a
risk based approach for control of
Cryptosporidium in drinking water.
Under this approach, the required level
of additional Cryptosporidium treatment
relates to the source water pathogen
density. EPA believes many of the data
gaps that prevented the adoption of this
approach under the IESWTR have been
addressed. As described in Section III of
this preamble, information on
Cryptosporidium occurrence from the
Information Collection Rule and
Information Collection Rule
Supplemental Surveys, along with new
data on Cryptosporidium infectivity,
have provided EPA with a better
understanding of the magnitude and
distribution of risk for this pathogen.
Improved analytical methods allow for
a more accurate assessment of source
water Cryptosporidium levels, and
recent disinfection studies with UV,
ozone, and chlorine dioxide provide the
technical basis to support
Cryptosporidium inactivation
requirements.
6. Control of Cryptosporidium in
unfiltered systems. There is particular
concern about Cryptosporidium in the
source waters of unfiltered systems
because this pathogen has been shown
to be resistant to conventional
disinfection practices. In the IESWTR,
EPA extended watershed control
requirements for unfiltered systems to
include the control of Cryptosporidium.
EPA did not establish Cryptosporidium
treatment requirements for unfiltered
systems because available data
suggested an equivalency of risk in
filtered and unfiltered systems. This is
described in the final IESWTR as
follows:
it appears that unfiltered water systems that
comply with the source water requirements
of the SWTR have a risk of cryptosporidiosis
equivalent to that of a water system with a
well operated filter plant using a water
source of average quality f63 FR 69492, Dec.
16, 1998) (USEPA 1998a)
The Agency noted that data from the
Information Collection Rule would
provide more information on
Cryptosporidium levels in filtered and
unfiltered systems, and that
Cryptosporidium treatment
requirements would be re-evaluated
when these data became available.
In today's notice, EPA is proposing
Cryptosporidium inactivation
requirements for unfiltered systems.
These proposed requirements stem from
an assessment of Cryptosporidium
source water occurrence in both filtered
and unfiltered systems using data from
the Information Collection Rule and
other surveys, as described in Section III
of this preamble. These new data do not
support the finding described in the
IESWTR of equivalent risk in filtered
and unfiltered systems. Rather,
Cryptosporidium treatment by
unfiltered systems is necessary to
achieve a finished water risk level
equivalent to that of filtered systems. In
addition, the development of
Cryptosporidium inactivation criteria
for UV, ozone, and chlorine dioxide in
the LT2ESWTR has made it feasible for
unfiltered systems to provide
Cryptosporidium treatment.
c. Uncovered finished water storage
facilities. In the IESWTR proposal, EPA
solicited comment on a requirement that
systems cover finished water storage
facilities to reduce the potential for
contamination by pathogens and
hazardous chemicals. Potential sources
of contamination to uncovered storage
facilities include airborne chemicals,
runoff, animal carcasses, animal or bird
droppings, and growth of algae and
other aquatic organisms (59 FR 38832,
July 29, 1994) (USEPA 1994). '
The final IESWTR established a
requirement to cover all new storage
facilities for finished water for which
construction began after February 16,
1999 (63 FR 69493, Dec. 16, 1998)
(USEPA 1998a). In preamble to the final
IESWTR, EPA described future
regulation of existing uncovered
finished water storage facilities as
follows:
EPA needs more time to collect and
analyze additional information to evaluate
regulatory impacts on systems with existing
uncovered reservoirs on a national basis . . .
EPA will further consider whether to require
the covering of existing reservoirs during the
development of subsequent microbial
regulations when additional data and
analysis to develop the national costs of
coverage are available.
EPA continues to be concerned about
contamination resulting from uncovered
finished water storage facilities,
particularly the potential for vims
contamination via bird droppings, and
now has sufficient data to estimate
national cost implications for various
regulatory control strategies. Therefore,
EPA is proposing control measures for
all systems with uncovered finished
water storage facilities in the
LT2ESWTR. New data and proposed
requirements are described in section
IV.E of this preamble.
D. Federal Advisory Committee Process
In March 1999, EPA reconvened the
M-DBP Federal Advisory Committee to
develop recommendations for the Stage
2 DBPR and LT2ESWTR. The
Committee consisted of organizational
members representing EPA, State and
local public health and regulatory
agencies, local elected officials, Indian
Tribes, drinking water suppliers,
chemical and equipment manufacturers,
and public interest groups. Technical
support for the Committee's discussions
was provided by a technical workgroup
established by the Committee at its first
meeting. The Committee's activities
resulted in the collection and evaluation
of substantial new information related
to key elements for both rules. This
included new data on pathogenicity,
occurrence, and treatment of microbial
contaminants, specifically including
Cryptosporidium, as well as new data on
DBF health risks, exposure, and control.
New information relevant to the
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LT2ESWTR is summarized in Section III
of this proposal.
In September 2000, the Committee
signed an Agreement in Principle
reflecting the consensus
recommendations of the group. The
Agreement was published in a
December 29, 2000 Federal Register
notice (65 FR 83015, December 29,
2000) (USEPA 2000a). The Agreement is
divided into Parts A & B. The entire
Committee reached consensus on Part
A, which contains provisions that
directly apply to the Stage 2 DBPR and
LT2ESWTR. The full Committee, with
the exception of one member, agreed to
Part B, which has recommendations for
future activities by EPA in the areas of
distribution systems and microbial
water quality criteria.
The Committee reached agreement on
the following major issues discussed in
this notice and the proposed Stage 2
DBPR:
LT2ESWTR: (1) Additional
Cryptosporidium treatment based on
source water monitoring results; (2)
Filtered systems that must comply with
additional Cryptosporidium treatment
requirements may choose from a
"toolbox" of treatment and control
options; (3) Reduced monitoring burden
for small systems; (4) Future monitoring
to confirm source water quality
assessments; (5) Cryptosporidium
inactivation by all unfiltered systems;
(6) Unfiltered systems meet overall
inactivation requirements using a
minimum of 2 disinfectants; (7)
Development of criteria and guidance
for UV disinfection and other toolbox
options; (8) Cover or treat existing
uncovered finished water reservoirs
(i.e., storage facilities) or implement risk
mitigation plans.
Stage 2 DBPR: (1) Compliance
calculation for total trihanomethanes
(TTHM) and five haloacetic acids
(HAA5) revised from a running annual
average (RAA) to a locational running
annual average (LRAA); (2) Compliance
carried out in two phases of the rule; (3)
Performance of an Initial Distribution
System Evaluation; (4) Continued
importance of simultaneous compliance
with DBF and microbial regulations; (5)
Unchanged MCL for bromate.
III. New Information on
Cryptosporidium Health Risks and
Treatment
The purpose of this section is to
describe information related to health
risks and treatment of Cryptosporidium
in drinking water that has become
available since EPA developed the
IESWTR. Much of this information was
evaluated by the Stage 2 M-DBP Federal
Advisory Committee when considering
whether and to what degree existing
microbial standards should be revised to
protect public health. It serves as a basis
for the recommendations made by the
Advisory Committee and for provisions
in today's proposed rule. This section
begins with an overview of critical
factors that EPA considers when
evaluating regulation of microbial
pathogens. New information is then
presented on three key topics:
Cryptosporidium infectivity,
occurrence, and treatment.
A. Overview of Critical Factors for
Evaluating Regulation ofMicrobia]
Pathogens
When proposing a national primary
drinking water regulation that includes
a maximum contaminant level or
treatment technique, SDWA requires
EPA to analyze the health risk reduction
benefits and costs likely to result from
alternative regulatory levels that are
being considered. For assessing risk,
EPA follows the paradigm described by
the National Academy of Science (NRC,
1983) which involves four steps: (1)
Hazard identification, (2) dose-response
assessment, (3) exposure assessment,
and (4) risk characterization. The
application of these steps to microbial
pathogens is briefly described in this
section, followed by a summary of how
EPA estimates the health benefits and
costs of regulatory alternatives.
Hazard identification for microbial
pathogens is a description of the nature,
severity, and duration of the health
effects stemming from infection. Under
SDWA, EPA must consider health
effects on the general population and on
subpopulations that are at greater risk of
adverse health effects. See section II.C.2
of this preamble for health effects
associated with Cryptosporidium.
Dose-response assessment with
microorganisms is commonly termed
infectivity and is a description of the
relationship between the number of
pathogens ingested and the probability
of infection. Information on
Cryptosporidium infectivity is presented
in section III.B of this preamble.
Exposure to microbial pathogens in
drinking water is generally a function of
the concentration of the pathogen in
finished water and the volume of water
ingested (exposure also occurs through
secondary routes involving infected
individuals). Because it is difficult to
directly measure pathogens at the low
levels typically present in finished
water, EPA's information on pathogen
exposure is primarily derived from
surveys of source water occurrence. EPA
estimates the concentration of
pathogens in treated water by
combining source water pathogen
occurrence data with information on the
performance of treatment plants in
reducing pathogen levels. Data on the
occurrence of Cryptosporidium are
described in section III.C of this
preamble and in Occurrence and
Exposure Assessment for the
LT2ESWTR {USEPA 2003b).
Cryptosporidium treatment studies are
described in section HI.D of this
preamble.
Risk characterization is the
culminating step of the risk assessment
process. It is a description of the nature
and magnitude of risk, and characterizes
strengths, weaknesses, and attendant
uncertainties of the assessment. EPA's
risk characterization for
Cryptosporidium is described in
Economic Analysis for the LT2ESWTR
(USEPA 2003a).
Estimating the health benefits and
costs that would result from a new
regulatory requirement involves a
number of steps, including evaluating
the efficacy and cost of treatment
strategies to reduce exposure to the
contaminant, forecasting the number of
systems that would implement different
treatment strategies to comply with the
regulatory standard, and projecting the
reduction in exposure to the
contaminant and consequent health risk
reduction benefits stemming from
regulatory compliance. EPA's estimates
of health benefits and costs associated
with the proposed LT2ESWTR are
presented in Economic Analysis for the
LT2ESWTR (USEPA 2003a) and are
summarized in section VI of this
preamble.
B. Cryptosporidium Infectivity
This section presents information on
the infectivity of Cryptosporidium
oocysts. Infectivity relates the
probability of infection by
Cryptosporidium with the number of
oocysts that a person ingests, and it is
used to predict the disease burden
associated with different
Cryptosporidium levels in drinking
water. Information on Cryptosporidium
infectivity comes from dose-response
studies where healthy human subjects
ingest different numbers of oocysts and
are subsequently evaluated for signs of
infection and illness.
Data from a human dose-response
study of one Cryptosporidium isolate
(the IOWA study, conducted at the
University of Texas-Houston Health
Science Center) had been published
prior to the IESWTR (DuPont et al.
1995). Following IESWTR
promulgation, a study of two additional
isolates (TAMU and UCP) was
completed and published (Okhuysen et
al, 1999). This study also presented a
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47651
reanalysis of the IOWA study results. As
described in more detail later in this
section, this new study indicates that
the infectivity of Cryptosporidium
oocysts varies over a wide range. The
UCP oocysts appeared less infective
than those of the IOWA study while the
TAMU oocysts were much more
infective. Although the occurrence of
these isolates among environmental
oocysts is unknown, a meta-analysis of
these data conducted by EPA suggests
the overall infectivity of
Cryptosporidiutn may be significantly
greater than was estimated for the
IESWTR. (USEPA 2003a).
This section begins with a description
of the infectivity data considered for the
IESWTR. This is followed by a
presentation of additional data that have
been evaluated for the proposed
LT2ESWTR and a characterization of
the significance of these new data.
1. Cryptosporidium Infectivity Data
Evaluated for IESWTR
Data from the IOWA study (DuPont et
al. 1995) were evaluated for the
IESWTR. In that study, 29 individuals
were given single doses ranging from 30
oocysts to 1 million oocysts. This oocyst
isolate was originally obtained from a
naturally infected calf. Seven persons
received doses above 500, and all were
infected. Eleven of the twenty two
individuals receiving doses of 500 or
fewer were classified as infected based
on oocysts detected in stool samples.
The IOWA study data were analyzed
using an exponential dose-response
model established by Haas et al. (1996)
for Cryptosporidium:
Probability {Infection/Dose} =
•j _ g — Dose/k
Based on the maximum likelihood
estimate of k (238), the probability of
infection from ingesting a single oocyst
(1/k) is approximately 0.4% (4 persons
infected for every 1,000 who each ingest
one oocyst). Based on the same estimate,
the dose at which 50% of persons
become infected (known as the median
infectious dose or ID50) is 165.
2. New Data on Cryptosporidium
Infectivity
A study of two additional
Cryptosporidium isolates was
conducted at the University of Texas-
Houston Health Science Center
(Okhuysen et al. 1999). One of the
isolates (UCP) was originally collected
from naturally infected calves. The
other isolate (TAMU) was originally
collected from a veterinary student who
became infected during necropsy on an
infected foal.
The TAMU and UCP studies were
conducted with 14 and 17 subjects,
respectively. Because thousands of
oocysts per gram of stool can go
undetected, researchers elected to use
both stool test results and symptoms as
markers of infection (only stool test
results had been used for the IOWA
study). Under this definition, two
additional IOWA subjects were regarded
as having been infected. As shown in
Table III-l, all but two of the TAMU
subjects were presumed infected and all
but six of the UCP subjects were
presumed infected following ingestion
of the indicated oocyst doses.
TABLE MM.—Cryptosporidium
Parvum INFECTIVITY IN HEALTHY
ADULT VOLUNTEERS
TABLE III-1.—Cryptosporidium
Parvum INFECTIVITY IN HEALTHY
ADULT VOLUNTEERS—Continued
Isolate and dose
(# of oocysts)
IOWA:
30
100
300
500
1,000
10,000
100,000
1,000,000
TAMU:
10
30
100
Number of
subjects 1
5
8
3
6
2
3
1
1
3
3
3
Number in-
fected 1
2
4
2
5
2
3
1
1
2
2
3
Isolate and dose
(# of oocysts)
500
UCP:
500
1,000
5,000
10.000
Number of
subjects 1
5
5
3
5
4
Number in-
fected 1
5
3
2
2
4
two right columns list the number of
subjects belonging to each category.
EPA conducted a meta-analysis of
these results in which the three isolates
were considered as a random sample (of
size three) from a larger population of
environmental oocysts (Messner et al.
2001). This meta analysis was reviewed
by the Science Advisory Board (SAB). In
written comments from a December
2001 meeting of the Drinking Water
Committee, SAB members
recommended the following: (1) two
assumed infectivity distributions (of
parameter r = 1/k as logit normal and
logit-t) should be used in order to
characterize uncertainty and (2) EPA
should consider excluding the UCP data
set because it seems to be an outlier (see
Section VII.K). In response, EPA has
used the two recommended
distributions for infectivity and has
conducted the meta-analysis both with
and without the UCP data due to
uncertainty about whether it is
appropriate to exclude these data.
Table HI-2 presents meta-analysis
estimates of the probability of infection
given one oocyst ingested. Results are
shown for the four different analysis
conditions (log normal and log-t
distributions; with and without UCP
data) as well as a combined result
derived by sampling equally from each
distribution, A more complete
description of the infectivity analysis is
provided in Economic Analysis for the
LT2ESWTR (USEPA 2003a).
TABLE 111-2.—RISK OF INFECTION, GIVEN ONE OOCYST INGESTED
Basis for analysis
Studies used
IOWA, TAMU, and UCP
IOWA, TAMU, and UCP
IOWA and TAMU
IOWA and TAMU
Distributional model
Student's t {3df}1
Student's t (3df) 1
Probability of infection,
one oocyst ingested
Mean
0.07
0.09
0.09
0.10
0.09
80% Cred-
ible interval
0.007-0.19
0.015-0.20
0.011-0.23
0.014-0.25
0.011-0.22
' Student's t distribution with 3 degrees of freedom (3df)-
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The results in Table III-2 show that
the mean probability of infection from
ingesting a single infectious oocyst
ranges from 7% to 10% depending on
the assumptions used. In comparison,
the best estimate in the IESWTR of this
probability was 0.4%, based on the
IOWA isolate alone, and using the
earlier definition of infection. Thus,
these data suggest that both the range
and magnitude of Cryptosporidium
infectivity is higher than was estimated
in the final IESWTR.
It should be noted that although
significantly more data on
Cryptosporidium infectivity are
available now than when EPA
established the IESWTR, there remains
uncertainty about this parameter in
several areas. It is unknown how well
the oocysts used in the feeding studies
represent Cryptosporidium naturally
occurring in the environment, and the
analyses do not fully account for
variability in host susceptibility and the
effect of previous infections.
Furthermore, the sample sizes are
relatively small, and the confidence
bands on the estimates span more than
an order of magnitude. Another
limitation is that none of the studies
included doses below 10 oocysts, while
when people ingest oocysts in drinking
water it is usually a single oocyst.
3. Significance of New Infectivity Data
The new infectivity data reveal that
oocysts vary greatly in their ability to
infect human hosts. Moreover, due to
this variability and the finding of a
highly infectious isolate, TAMU, the
overall population of oocysts appears to
be more infective than assumed for the
IESWTR. The meta-analysis described
earlier indicates the probability of
infection at low Cryptosporidium
concentrations may be about 20 times as
great as previously estimated (which
was based on the IOWA isolate alone
and using the earlier definition of
infection (stool-confirmed infections)).
C. Cryptosporidium Occurrence
This section presents information on
the occurrence of Cryptosporidivm
oocysts in drinking water sources.
Occurrence information is important
because it is used in assessing the risk
associated with Cryptosporidium in
both filtered and unfiltered systems, as
well as in estimating the costs and
benefits of the proposed LT2ESWTR.
For the IESWTR, EPA had no national
survey data and relied instead on
several studies that were local or
regional. Those data suggested that a
typical (median) filtered surface water
source had approximately 2
Cryptosporidium oocysts per liter, while
a typical unfiltered surface water source
had about 0.01 oocysts per liter, a
difference of two orders of magnitude.
Subsequent to promulgating the
IESWTR, EPA obtained data from two
national surveys: the Information
Collection Rule and the Information
Collection Rule Supplemental Surveys
(ICRSSJ. These surveys were designed to
provide improved estimates of
occurrence on a national basis. As
described in more detail later in this
section, the Information Collection Rule
and ICRSS results show three main
differences in comparison to
Cryptosporidium occurrence data used
for the IESWTR:
(1) Average Cryptosporidium occurrence is
lower. Median oocyst levels for the
Information Collection Rule and ICRSS data
are approximately 0.05/L, which is more than
an order of magnitude lower than IESWTR
estimates.
(2) Cryptosporidium occurrence is more
variable from location to location than was
shown by the data considered for the
IESWTR. This indicates that although
median occurrence levels are below those
assumed for the IESWTR, there is a subset of
systems whose levels are considerably greater
than the median.
(3) There is a smaller difference in
Cryptosporidium levels between typical
filtered and unfiltered system water sources.
The Information Collection Rule data do not
support the IESWTR finding that unfiltered
water systems have a risk of
cryptosporidiosis equivalent to that of a filter
plant with average quality source water.
This section begins with a summary
of occurrence data that were used to
assess risk under the IESWTR (these
data were also used in the main risk
assessment for the LTlESWTR). This is
followed by a discussion of the
Information Collection Rule and ICRSS
that covers the scope of the surveys,
analytical methods, results, and a
characterization of how these new data
impact current understanding of
Cryptosporidium exposure. A more
detailed description of occurrence data
is available in Occurrence and Exposure
Assessment for the Long Term 2
Enhanced Surface Water Treatment Rule
(USEPA 2003b).
1. Occurrence Data Evaluated for
IESWTR
Occurrence information evaluated for
the IESWTR is detailed in Occurrence
and Exposure Assessment for The
Interim Enhanced Surface Water
Treatment Rule (USEPA 1998c). This
information is summarized in the next
two paragraphs.
a. Filtered systems. In developing the
IESWTR, EPA evaluated
Cryptosporidium occurrence data from a
number of studies. Among these studies,
LeChevallier and Norton (1995)
produced the largest data set and data
from this study were used for the
IESWTR risk assessment. This study
provided estimates of mean occurrence
at 69 locations from the eastern and
central U.S. Although limited by the
small number of samples per site (one
to sixteen samples; most sites were
sampled five times), variation within
and between sites appeared to be
lognormal. The study's median
measured source water concentration
was 2.31 oocysts/L and the interquartile
range (i.e., 25th and 75th percentile)
was 1.03 to 5.15 oocysts/L.
b. Unfiltered systems. To assess
Cryptosporidium occurrence in
unfiltered systems under the IESWTR,
EPA evaluated Cryptosporidium
monitoring results from several
unfiltered water systems that had been
summarized by the Seattle Water
Department (Montgomery Watson,
1995). The median (central tendency) of
these data was approximately 0.01
oocysts/L. Thus, the median
concentration in these data set was
about 2 orders of magnitude less than
the median concentration in the data set
used for filtered systems. These data,
coupled with the assumption that
filtered systems will remove at least 2
log of Cryptosporidium as required by
the IESWTR, suggested that unfiltered
systems that comply with the source
water requirements of the SWTR may
have a risk of cryptosporidiosis
equivalent to that of a filter plant using
a water source of average quality (62 FR
59507, November 3,1997) (USEPA
1997a).
2. Overview of the Information
Collection Rule and Information
Collection Rule Supplemental Surveys
(ICRSS)
The Information Collection Rule and
the Information Collection Rule
Supplemental Surveys (ICRSS) were
national monitoring studies. They were
designed to provide EPA with a more
comprehensive understanding of the
occurrence of microbial pathogens in
drinking water sources in order to
support regulatory decision making. The
surveys attempted to control protozoa
measurement error through requiring
that (1) laboratories meet certain
qualification criteria, (2) standardized
methods be used to collect data, and (3)
laboratories analyze performance
evaluation samples throughout the
duration of the study to ensure adequate
analytical performance. Information
Collection Rule monitoring took place
from July 1997 to December 1998;
ICRSS Cryptosporidium monitoring
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47653
began in March 1999 and ended in
February 2000.
a. Scope of the Information Collection
Rule. The Information Collection Rule
(61 FR 24354, May 14,1996) (USEPA
1996a) required large PWSs to collect
water quality and treatment data related
to DBFs and microbial pathogens over
an 18-month period. PWSs using surface
water or ground water under the direct
influence of surface water as sources
and serving at least 100,000 people were
required to monitor their raw water
monthly for Cryptosporidium, Giardia,
viruses, total coliforms, and E. coli.
Approximately 350 plants monitored for
microbial parameters.
b. Scope of the ICHSS. The ICRSS
were designed to complement the
Information Collection Rule* data set
with data from systems serving fewer
than 100,000 people and by employing
an improved analytical method for
protozoa (described later). The ICRSS
included 47 large systems (serving
greater than 100,000 people), 40
medium systems (serving 10,000 to
100,000 people) and 39 small systems
(serving fewer than 10,000 people).
Medium and large systems conducted 1
year of twice-per-month sampling for
Cryptosporidium, Giardia , temperature,
pH, turbidity, and coliforms. Other
water quality measurements were taken
once a month. Small systems did not
test for protozoa but tested for all other
water quality parameters.
3. Analytical Methods for Protozoa in
the Information Collection Rule and
ICRSS
This subsection describes analytical
methods for Cryptosporidium that were
used in the Information Collection Rule
and ICRSS. Information on
Cryptosporidium analytical methods is
important for the LT2ESWTR for several
reasons: (1) It is relevant to the quality
of Cryptosporidium occurrence data
used to assess risk and economic impact
of the LT2ESWTR proposal, (2) it
provides a basis for the statistical
procedures employed to analyze the
occurrence data, and (3) it is used to
assess the adequacy of Cryptosporidium
methods to support source-specific
decisions under the LT2ESWTR.
The Information Collection Rule and
ICRSS data sets were generated using
different analytical methods. The
Information Collection Rule Protozoan
Method (ICR Method) was used to
analyze water samples for
Cryptosporidium during the Information
Collection Rule. For the ICRSS, a similar
but improved method, EPA Method
1622 (later 1623), was used for protozoa
analyses (samples were analyzed for
Cryptosporidium using Method 1622 for
the first 4 months; then Method 1623
was implemented so that Giardia
concentrations could also be measured).
a. Information Collection Rule
Protozoan Method. With the
Information Collection Rule Method
(USEPA 1996b), samples were collected
by passing water through a filter, which
was then delivered to an EPA-approved
Information Collection Rule laboratory
for analysis. The laboratory eluted the
filter, centrifuged the eluate, and
separated Cryptosporidium oocysts and
Giardia cysts from other debris by
density-gradient centrifugation. The
oocysts and cysts were then stained and
counted. Differential interference
contrast (DIG) microscopy was used to
examine internal structures.
The Information Collection Rule
Method provided a quantitative
measurement of Cryptosporidium
oocysts and Giardia cysts, but it is
believed to have generally
undercounted the actual occurrence
(modeling, described later, adjusted for
undercounting). This undercounting
was due to low volumes analyzed and
low method recovery. The volume
analyzed directly influences the
sensitivity of the analytical method and
the Information Collection Rule Method
did not require a specific volume
analyzed. As a result, sample volumes
analyzed during the Information
Coilection Rule varied widely,
depending on the water matrix and
analyst discretion, with a median
volume analyzed of only 3 L.
Method recovery characterizes the
likelihood that an oocyst present in the
original sample will be counted. Loss of
organisms may occur at any step of the
analytical process, including filtration,
elution, concentration of the eluate, and
purification of the concentrate. To
assess the performance of the
Information Collection Rule Method,
EPA implemented the Information
Collection Rule Laboratory Spiking
Program. This program involved
collection of duplicate samples on two
dates from 70 plants. On each occasion,
one of the duplicate samples was spiked
with a known quantity of Giardia cysts
and Cryptosporidium oocysts (the
quantity was unknown to the laboratory
performing the analysis), and both
samples were processed according to
the method. Recovery of spiked
Cryptosporidium oocysts ranged from
0% to 65% with a mean of 12% and a
standard deviation nearly equal to the
mean (relative standard deviation (RSD)
approximately 100%) (Scheller et al
2002).
b. Method 1622 and Method 1623.
EPA developed Method 1622 (detects
Cryptosporidium) and 1623 (detects
Cryptosporidium and Giardia) to
achieve higher recovery rates and lower
inter- and intra-laboratory variability
than previous methods. These methods
incorporate improvements in the
concentration, separation, staining, and
microscope examination procedures.
Specific improvements include the use
of more effective filters,
immunomagnetic separation (IMS) to
separate the oocysts and cysts from
extraneous materials present in the
water sample, and the addition of 4, 6-
diamidino-2-phenylindole (DAPI) stain
for microscopic analysis. The
performance of these methods was
tested through single-laboratory studies
and validated through multiple-
laboratory validation (round robin)
studies.
The per-sample volume analyzed for
Cryptosporidium during the ICRSS was
larger than in the Information Collection
Rule, due to a requirement that
laboratories analyze a minimum of 10 L
or 2 mL of packed pellet with Methods
1622/23 (details in section IV.K). To
assess method recovery, matrix spike
samples were analyzed on five sampling
events for each plant. The protozoa
laboratory spiked the additional sample
with a known quantity of
Cryptosporidium oocysts and Giardia
cysts (the quantity was unknown to the
laboratory performing the analysis) and
filtered and analyzed both samples
using Methods 1622/23. Recovery in the
ICRSS matrix spike study averaged 43%
for Cryptosporidium with an RSD of
47% (Conneli et al. 2000). Thus, mean
Cryptosporidium recovery with
Methods 1622/23 under the ICRSS was
more than 3.5 times higher than mean
recovery in the Information Collection
Rule lab spiking program and relative
standard deviation was reduced by more
than half.
Although Methods 1622 and 1623
have several advantages over the
Information Collection Rule method,
they also have some of the same
limitations. These methods do not
determine whether a cyst or oocyst is
viable and infectious, and both methods
require a skilled microscopist and
several hours of sample preparation and
analyses.
4. Cryptosporidium Occurrence Results
from the Information Collection Rule
and ICRSS
This section describes
Cryptosporidium monitoring results
from the Information Collection Rule
and ICRSS. The focus of this discussion
is the national distribution of mean
Cryptosporidium occurrence levels in
the sources of filtered and unfiltered
plants.
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The observed (raw, unadjusted)
Cryptosporidium data from the
Information Collection Rule and ICRSS
do not accurately characterize true
concentrations because of (a) the low
and variable recovery of the analytical
method, (b) the small volumes analyzed,
and (c) the relatively small number of
sample events. EPA employed a
statistical treatment to estimate the true
underlying occurrence that led to the
data observed in the surveys and to
place uncertainty bounds about that
estimation.
A hierarchical model with Bayesian
parameter estimation techniques was
used to separately analyze filtered and
unfiltered system data from the
Information Collection Rule and the
large and medium system data from the
ICRSS. The model included parameters
for location, month, source water type,
and turbidity. Markov Chain Monte
Carlo methods were used to estimate
these parameters, producing a large
number of estimate sets that represent
uncertainty. This analysis is described
more completely in Occurrence and
Exposure Assessment for the Long Term
2 Enhanced Surface Water Treatment
Rule (USEPA 2003b).
a. Information Collection Rule results.
Figure HI-1 presents plant-mean
Cryptosporidium levels for Information
Collection Rule plants as a cumulative
distribution. Included in Figure III-l are
distributions of both the observed raw
data adjusted for mean analytical
method recovery of 12% and the
modeled estimate of the underlying
distribution, along with 90% confidence
bounds. The two distributions (observed
and modeled) are similar for plants
where Cryptosporidium was detected
(196 of 350 Information Collection Rule
plants did not detect Cryptosporidium
in any source water samples). The
modeled distribution allows for
estimation of Cryptosporidium
concentrations in sources where oocysts
may have been present but were not
detected due to low sample volume and
poor method recovery (this concept is
explained further later in this section).
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Collection Rule data is broader (i.e.,
more source-to-source variability). Also,
the occurrence of Cryptosporidium in
flowing stream sources was greater and
more variable than in reservoir/lake
sources (shown in USEPA 2003b).
The fact that only 44% of Information
Collection Rule plants had one or more
samples positive for Cryptosporidium
and that only 7% of all Information
Collection Rule samples were positive
for Cryptosporidium suggests that
oocyst levels were relatively low in
many source waters. However, as noted
earlier, it is expected that
Cryptosporidium oocysts were present
in many more source waters at the time
of sampling and were not detected due
to poor analytical method recovery and
low sample volumes.
This concept is illustrated by Figure
III-2, which shows the likelihood of no
oocysts being detected by the
Information Collection Rule method as
a function of source water concentration
(assumes median Information Collection
Rule sample volume of 3 L). As can be
seen in Figure III—2, when the source
water concentration is 1 oocyst/L,
which is a relatively high level, the
probability of no oocysts being detected
in a 3 L sample is 73%; for a source
water with 0.1 oocyst/L, which is close
to the median occurrence level, the
probability of a non-detect is 97%.
Consequently, EPA has concluded that
it is appropriate and necessary to use a
statistical model to estimate the
underlying distribution.
EPA modeled Cryptosporidium
occurrence separately for filtered and
unfiltered plants that participated in the
Information Collection Rule because
unfiltered plants comply with different
regulatory requirements than filtered
plants. As shown in Table III—3, the
occurrence of Cryptosporidium was
lower for unfiltered sources.
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Figure 111-2.-- Probability of No Oocysts Being Detected by the Information
Collection Rule Method as a Function of Source Water Cryptosporidium
Concentration
BILLING CODE 6560-50-C
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Federal Register/Vol. 68, No. 154/Monday, August 11, 2003/Proposed Rules
TABLE 111-3.—- SUMMARY OF INFORMATION COLLECTION RULE Cryptosporidium MODELED SOURCE WATER DATA FOR
UNFJLTERED AND FILTERED PLANTS
Information collection rule
modeled plant-mean
(oocysts/L)
Mean
0.014
0.59
Median
0.0079
0.052
90th
per-
centile
0.033
1.4
The median Cryptosporidium
occurrence level for unfiltered systems
in the Information Collection Rule was
0.0079 oocysts/L, which is close to the
median level of 0.01 oocysts/L reported
for unfiltered systems in the IESWTR
(Montgomery Watson, 1995). However,
the Information Collection Rule data do
not show the 2 log difference in median
Cryptosporidium levels between filtered
and unfiltered systems that was
observed for the data used in the
IESWTR. The ratio of median plant-
mean occurrence in unfiltered plants to
filtered plants is about 1:7 (see Table
III-3). Thus, based on an assumption of
a minimum 2 log removal of
Cryptosporidium by filtration plants (as
required by the IESWTR and
LT1ESWTR), these data indicate that, on
average, finished water oocysts levels
are higher in unfiltered systems than in
filtered systems.
b. ICRSS results. Figures III-3 and III-
4 present plant-mean Cryptosporidium
levels for ICRSS medium and large
systems, respectively, as cumulative
distributions. Medium and large system
data were analyzed separately to
identify differences between the two
data sets. Similar to the Information
Collection Rule data plot, Figures III-3
and III-4 include distributions for both
the observed raw data adjusted for mean
analytical method recovery of 43% and
the modeled estimate of the underlying
distribution, along with 90% confidence
bounds. The observed and modeled
distributions are similar for the 85% of
ICRSS plants that detected
Cryptosporidium, and the modeled
distribution allows for estimation of
Cryptosporidium concentrations for
source waters where oocysts may have
been present but were not detected.
Plant-mean Cryptosporidium
concentrations for large and medium
systems in the ICRSS are similar at the
mid and lower range of the distribution
and differ at the upper end. ICRSS
medium and large systems both had
median plant-mean Cryptosporidium
levels of approximately 0.05 oocysts/L,
which is close to the median oocyst
level in the Information Collection Rule
data set as well. However, the 90th
percentile plant-mean was 0.33 oocysts/
L for ICRSS medium systems and 0.24
oocysts/L for ICRSS large systems. Note
that in the Information Collection Rule
distribution, the 90th percentile
Cryptosporidium concentration is 1.3
oocysts/L, which is significantly higher
than either the ICRSS medium or large
system distribution.
The reasons for different results
between the surveys are not well
understood, but may stem from year-to-
year variation in occurrence, systematic
differences in the sampling or
measurement methods employed, and
differences in the populations sampled.
This topic is discussed further at the
end of this section.
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,>-o-o-o-o-o-o
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detected no oocysts
-o-o-o-o-o/o^oy
Modeled Distribution
(with 90% confidence bounds)
1e-005 0.0001 0.001 0.01 0.1 1 10
Plant-Mean Cryptosporidium Concentration (oocysts/L)
100
Figure III-3.-- Plant-Mean Cryptosporidium Levels for ICRSS Medium Plants
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0,0 o o o
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(with 90% confidence bounds)
1e-005 0.0001 0.001 0.01 0.1 1 10
Plant-Mean Cryptosporidium Concentration (oocysts/L)
100
Figure III-4.-- Plant-Mean Cryptosporidium Levels for ICRSS Large Plants
BILLING CODE 6560-SO-C
5. Significance of new
Cryptosporidium occurrence data.
The Information Collection Rule and
ICRSS data substantially improve
overall knowledge of the occurrence
distribution of Cryptosporidium in
drinking water sources. They provide
data on many more water sources than
were available when the IESWTR was
developed and the data are of more
uniform quality. In regard to filtered
systems, these new data demonstrate
two points:
(1) The occurrence of Cryptosporidium in
many drinking water sources is lower than
was indicated by the data used in IESWTR.
Median plant-mean levels for the Information
Collection Rule and ICRSS data sets are
approximately 0.05 oocysts/L, whereas the
median oocyst concentration in the
LeChevallier and Norton (1995) data used in
the IESWTR risk assessment was 2.3 oocysts/
L.
(2) Cryptosporidium occurrence is more
variable from plant to plant than was
indicated by the data considered for the
IESWTR (i.e., occurrence distribution is
broader). This is illustrated by considering
the ratio of the 90th percentile to the median
plant-mean concentration. In the
LeChevallier and Norton (1995) data used for
the IESWTR, this ratio was 4.6, whereas in
the Information Collection Rule data, this
ratio is 27.
These data, therefore, support the
finding that Cryptosporidium levels are
relatively low in most water sources, but
there is a subset of sources with
relatively higher concentrations where
additional treatment may be
appropriate.
In regard to unfiltered plants, the
Information Collection Rule data are
consistent with the Cryptosporidium
occurrence estimates for unfiltered
systems in the IESWTR. However, due
to the lower occurrence estimates for
filtered systems noted previously, the
Information Collection Rule data do not
support the IESWTR finding that
unfiltered water systems in compliance
with the source water requirements of
the SWTR have a risk of
cryptosporidiosis equivalent to that of a
well-operated filter plant using a water
source of average quality (63 FR 69492,
December 16,1998) (USEPA 1998a).
Rather, these data indicate that Agency
conclusions regarding the risk
comparison between unfiltered and
filtered drinking waters must be revised.
For protection equivalent to that
provided by filtered systems, unfiltered
systems must take additional steps to
strengthen their microbial barriers.
6. Request for Comment on Information
Collection Rule and ICRSS Data Sets
EPA notes that there are significant
differences in the Information
Collection Rule and ICRSS medium and
large system data sets. The median
values for these data sets are 0.048,
0.050, and 0.045 oocysts/L, respectively,
while the 90th percentile values are 1.3,
0.33, and 0.24 oocysts/L. The reasons
for these differences are not readily
apparent. The ICRSS used a newer
method with better quality control that
yields significantly higher recovery, and
this suggests that these data are more
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47659
reliable for estimating concentrations at
individual plants. However, the
Information Collection Ruie included a
much larger number of plants (350 v. 40
each for the ICRSS medium and large
system surveys) and, consequently, may
be more reliable for estimating
occurrence nationally. The surveys
included a similar number of samples
per plant (18 v. 24 in the ICRSS). The
two surveys cover different time periods
(7/97-12/98 for the Information
Collection Rule and 3/99-2/00 for the
ICRSS),
In order to better understand the
factors that may account for the
differences in the three data sets, EPA
conducted several additional analyses.
First, EPA compared results for the
subset of 40 plants that were in both the
Information Collection Rule and ICRSS
large system surveys. The medians for
the two data sets were 0.13 and 0.045
oocysts/L, respectively, while the 90th
percentiles were 1.5 and 0.24 oocysts/L.
Clearly, the discrepancy between the
two surveys persists for the subsample
of data from plants that participated in
both surveys. This suggests that the
different sample groups in the full data
sets are not the primary factor that
accounts for the different results.
Next, EPA looked at the six month
period (July through December) that was
sampled in two consecutive years (1997
and 1998) during the Information
Collection Rule survey to investigate
year-to-year variations at the same
plants. Estimated medians for 1997 and
1998 were 0.062 and 0.040 oocysts/L,
respectively, while the 90th percentiles
were 1.1 and 1.3 oocysts/L. While these
comparisons show some interyear
variability, it is less than the variability
observed between the Information
Collection Rule and ICRSS data sets.
EPA has no data comparing the same
plants using the same methods for the
time periods in question (1997-98 and
1999-2000) so it is not known if the
variation between these time periods
was larger than the apparent variation
between 1997 and 1998 in the
Information Collection Rule data set.
The choice of data set has a
significant effect on exposure, cost, and
benefit estimates for the LT2ESWTR.
Due to the lack of any clear criterion for
favoring one data set over the other,
EPA has conducted the analyses for this
proposed rule separately for each, and
presents a range of estimates based on
the three data sets. EPA requests
comment on this approach. EPA will
continue to evaluate the relative
strengths and limitations of the three
data sets, as well as any new data that
may become available for the final rule.
D. Treatment
1. Overview
This section presents information on
treatment processes for reducing the risk
from Cryptosporidium in drinking
water. Treatment information is critical
to two aspects of the LT2ESWTR: (1)
estimates of the efficiency of water
filtration plants in removing
Cryptosporidium are used in assessing
risk in treated drinking water and (2) the
performance and availability of
treatment technologies like ozone, UV
light, and membranes that effectively
inactivate or remove Cryptosporidium
impact the feasibility of requiring
additional treatment for this pathogen.
The majority of plants treating surface
water use conventional filtration
treatment, which is defined in 40 CFR
141.2 as a series of processes including
coagulation, flocculation,
sedimentation, and filtration. Direct
filtration, which is typically used on
sources with low particulate levels,
includes coagulation and filtration but
not sedimentation. Other common
filtration processes are slow sand,
diatomaceous earth (DE), membranes,
and bag and cartridge filters.
For the IESWTR (and later the
LT1ESWTR), EPA evaluated results
from pilot and full scale studies of
Cryptosporidium removal by various
types of filtration plants. Based on these
studies, EPA concluded that
conventional and direct filtration plants
meeting IESWTR filter effluent turbidity
standards will achieve a minimum 2 log
(99%) removal of Cryptosporidium. The
Agency reached the same conclusion for
slow sand and DE filtration plants
meeting SWTR turbidity standards.
Treatment credit for technologies like
membranes and bag and cartridge filters
was to be made on a product-specific
basis.
Subsequent to promulgating the
IESWTR and LTlESWTR, EPA has
reviewed additional studies of the
performance of treatment plants in
removing Cryptosporidium, as well as
other micron size particles (e.g., aerobic
spores) that may serve as indicators of
Cryptosporidium removal. As discussed
later in this section, the Agency has
concluded that these studies support an
estimate of 3 log (99.9%) for the average
Cryptosporidium removal efficiency of
conventional treatment plants in
compliance with the IESWTR or
LTlESWTR. Section IV.A describes how
this estimate of average removal
efficiency is used in determining the
need for additional Cryptosporidium
treatment under the LT2ESWTR.
Further, this estimate is consistent with
the Stage 2 M-DBP Agreement in
Principle, which states as follows:
The additional treatment requirements in
the (LT2ESWTR) bin requirement table are
based, in part, on the assumption that
conventional treatment plants in compliance
with the IESWTR achieve an average of 3 logs
removal of Cryptosporidium.
In addition, the Agency finds that
available data support an estimate of 3
log average Cryptosporidium removal
for well operated slow sand and DE
plants. Direct filtration plants are
estimated to achieve a 2.5 log average
Cryptosporidium reduction, in
consideration of the absence of a
sedimentation process in these plants.
The most significant developments in
the treatment of Cryptosporidium since
IESWTR promulgation are in the area of
inactivation. During IESWTR
development, EPA determined that
available data were not sufficient to
identify criteria for awarding
Cryptosporidium treatment credit for
any disinfectant. As presented in
section IV.C.14, EPA has now acquired
the necessary data to specify the
disinfectant concentrations and contact
times necessary to achieve different
levels of Cryptosporidium inactivation
with chlorine dioxide and ozone.
Additionally, recent studies have
demonstrated that UV light will produce
high levels of Cryptosporidium and
Giardia lamblia inactivation at low
doses. Section IV.C.15 provides criteria
for systems to achieve credit for
disinfection of Cryptosporidium,
Giardia lamblia, and viruses by UV.
This section begins with a summary
of treatment information considered for
the IESWTR and LTlESWTR, followed
by a discussion of additional data that
EPA has evaluated since promulgating
those regulations. Further information
on treatment of Cryptosporidium is
available in Technologies and Costs for
Control of Microbial Contaminants and
Disinfection Byproducts (USEPA
2003c), Occurrence and Exposure
Assessment for the Long Term 2
Enhanced Surface Water Treatment Rule
(USEPA 2003b) and section IV.C of this
preamble.
2. Treatment information considered for
the IESWTR and LTlESWTR
Treatment studies that were evaluated
during development of the IESWTR are
described in the IESWTR NODA (62 FR
59486, November 3,1997) (USEPA
1997b), the Regulatory Impact Analysis
for the IESWTR (USEPA 1998d), and
Technologies and Costs for the
Microbial Recommendations of the M/
DBF Advisory Committee (USEPA
1997b). Treatment information
considered in development of the
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LTlESWTR is described in the proposed
rule (65 FR 59486, April 10, 2000)
(USEPA 2000b). Pertinent information is
summarized in the following
paragraphs.
a. Physical removal. EPA evaluated
eight studies on removal of
Cryptosporidium by rapid granular
filtration for the IESWTR. These were
Patania etal. (1995), Nieminski and
Ongerth (1995), Ongerth and Pecoraro
(1995), LeChevallieT and Norton (1992),
LeChevallier et ai. (1991), Foundation
for Water Research (1994), Kelley et al.
(1995), and West et al. (1994). These
studies included both pilot and full
scale plants.
Full scale plants in these studies
typically demonstrated 2-3 log removal
of Cryptosporidium, and pilot plants
achieved up to almost 6 log removal
under optimized conditions. In general,
the degree of removal that can be
quantified in full scale plants is limited
because Cryptosporidium levels
following filtration are often below the
detection limit of the analytical method.
Pilot scale studies overcome this
limitation by seeding high
concentrations of oocysts to the plant
influent, but extrapolation of the
performance of a pilot plant to the
routine performance of full scale plants
is uncertain.
Cryptosporidium removal efficiency
in these studies was observed to depend
on a number of factors including: water
matrix, coagulant application, treatment
optimization, filtered water turbidity,
and the filtration cycle. The highest
removal rates were observed in plants
that achieved very low effluent
turbidities.
EPA also evaluated studies of
Cryptosporidium removal by slow sand
(Schuler and Ghosh 1991, Timms et al.
1995) and DE filtration (Schuler and
Gosh 1990) for the IESWTR. These
studies indicated that a well designed
and operated plant using these
processes could achieve 3 log or greater
removal of Cryptosporidium.
After considering these studies, EPA
concluded that conventional and direct
filtration plants in compliance with the
effluent turbidity criteria of the
IESWTR, and slow sand and DE plants
in compliance with the effluent
turbidity criteria established for these
processes by the SWTR, would achieve
at least 2 log removal of
Cryptosporidium. Recognizing that
many plants will achieve more than the
minimum 2 log reduction, EPA
estimated median Cryptosporidium
removal among filtration plants as near
3 log (99.9%) for the purpose of
assessing risk.
The LTlESWTR proposal included
summaries of additional studies of
Cryptosporidium removal by
conventional treatment (Dugan et al.
1999), direct filtration (Swertfeger et al.
1998), and DE filtration (Ongerth and
Hutton 1997). These studies supported
IESWTR conclusions stated previously
regarding the performance of these
processes. The LTlESWTR proposal
also summarized studies of membranes,
bag filters, and cartridge filters
(Jacangelo et al. 1995, Drozd and
Schartzbrod 1997, Hirata and
Hashimoto 1998, Goodrich et al. 1995,
Collins et al. 1996, Lykins et al. 1994,
Adham et al. 1998}. This research
demonstrated that these technologies
may be capable of achieving 2 log or .
greater removal of Cryptosporidium.
However, EPA concluded that variation
in performance among different
manufacturers and models necessitates
that determinations of treatment credit
be made on a technology-specific basis
(65 FR 19065, April 10, 2000) (USEPA
2000b).
b. Inactivation. In the IESWTR NODA
(62 FR 59486) (USEPA 1997a), EPA
cited studies that demonstrated that
chlorine is ineffective for inactivation of
Cryptosporidium at doses practical for
treatment plants (Korich et al. 1990,
Ransome et al. 1993, Finch et al 1997).
The Agency also summarized studies of
Cryptosporidium inactivation by UV,
ozone, and chlorine dioxide. EPA
evaluated these disinfectants to
determine if sufficient data were
available to develop prescriptive
disinfection criteria for
Cryptosporidium.
the studies of UV disinfection of
Cryptosporidium that were available
during IESWTR development were
inconclusive due to methodological
factors. These studies included:
Lorenzo-Lorenzo et al. (1993), Ransome
et al. (1993), Campbell et al. (1995),
Finch et al. (1997), and Clancy et al.
(1997). A common limitation among
these studies was the use of in vitro
assays, such as excystation and vital dye
staining, to measure loss of infectivity.
These assays subsequently were shown
to overestimate the UV dose needed to
inactivate protozoa (Clancy et al. 1998,
Craik et al. 2000). In another case, a
reactor vessel that blocked germicidal
light was used (Finch et al. 1997).
EPA evaluated the following studies
of ozone inactivation of
Cryptosporidium for the IESWTR:
Peeters et al. (1989), Korich et al. (1990),
Parker et al. (1993), Ransome et al.
(1993), Finch etal. (1997), Daniel etal
(1993), and Miltner et al (1997). These
studies demonstrated that ozone could
achieve high levels of Cryptosporidium
inactivation, albeit at doses much higher
than those required to inactivate
Giardia. Results of these studies also
exhibited significant variability due to
factors like different infectivity assays
and methods of dose calculation.
The status of chlorine dioxide
inactivation of Cryptosporidium during
IESWTR development was similar to
that of ozone. EPA evaluated a number
of studies that indicated that relatively
high doses of chlorine dioxide could
achieve significant inactivation of
Cryptosporidium (Peeters et al. 1989,
Korich et al. 1990, Ransome et al 1993,
Finch et al 1995 and 1997, and
LeChevallier et al 1997). Data from
these studies showed a high level of
variability due to methodological
differences, and the feasibility of high
chlorine dioxide doses was uncertain
due to the MCL for chlorite that was
established by the Stage 1 DBPR.
After reviewing these studies, EPA
and the Stage 1 Federal Advisory
Committee concluded that available
data were not adequate to award
Cryptosporidium inactivation credit for
UV, ozone, or chlorine dioxide.
3. New Information on Treatment for
Control of Cryptosporidium
a. Conventional filtration treatment
and direct filtration. This section
provides brief descriptions of seven
recent studies of Cryptosporidium
removal by conventional treatment and
direct filtration, followed by a summary
of key points.
Dugan et al (2001) evaluated the
ability of conventional treatment to
control Cryptosporidium under varying
water quality and treatment conditions,
and assessed turbidity, total particle
counts (TPC), and aerobic endospores as
indicators of Cryptosporidium removal.
Fourteen runs were conducted on a
small pilot scale plant that had been
determined to provide equivalent
performance to a larger plant. Under
optimal coagulation conditions, oocyst
removal across the sedimentation basin
ranged from 0.6 to 1.8 log, averaging 1.3
log, and removal across the filters
ranged from 2.9 to greater than 4.4 log,
averaging greater than 3.7 log. Removal
of aerobic spores, TPC, and turbidity all
correlated with removal of
Cryptosporidium by sedimentation, and
these parameters were conservative
indicators of Cryptosporidium removal
across filtration. Sedimentation removal
under optimal conditions related to raw
water quality, with the lowest
Cryptosporidium removals observed
when raw water turbidity was low.
Suboptimal coagulation conditions
(underdosed relative to jar test
predictions) significantly reduced plant
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47661
performance. Oocyst removal in the
sedimentation basin averaged 0.2 log,
and removal by filtration averaged 1.5
log. Under suboptimal coagulation
conditions, low sedimentation removals
of Cryptosporidium were observed
regardless of raw water turbidity.
Nieminski and Bellamy (2000)
investigated surrogates as indicators of
Giardia and Cryptosporidium in source
water and as measures of treatment
plant effectiveness. It involved sampling
for microbial pathogens (Giardia,
Cryptosporidium, and enteric viruses),
potential surrogates (bacteria, bacteria
spores, bacterial phages, turbidity,
particles), and other water quality
parameters in the source and finished
waters of 23 surface water filtration
facilities and one unfiltered system.
While Giardia and Cryptosporidium
were found in the majority of source
water samples, the investigators could
not establish a correlation between
either occurrence or removal of these
protozoa and any of the surrogates
tested. This was attributed, in part, to
low concentrations of Giardia and
Cryptosporidium in raw water and high
analytical method detection limits.
Removal of Cryptosporidium and
Giardia averaged 2.2 and 2.6 log,
respectively, when conservatively
estimated using detection limits in
filtered water. Aerobic spores were
found in 85% of filtered water samples
and were considered a measure of
general treatment effectiveness. Average
reduction of aerobic spores was 2.84 log.
Direct filtration plants removed fewer
aerobic spores than conventional or
softening plants.
McTigue et al. (1998) conducted an
on-site survey of 100 treatment plants
for particle counts, pathogens
(Cryptosporidium and Giardia), and
operational information. The authors
also performed pilot scale spiking
studies. Median removal of particles
greater than 2 mm was 2.8 log, with
values ranging from 0.04 to 5.5 log.
Removal generally increased with
increasing raw water particle
concentration. Results were consistent
with previously collected data.
Cryptosporidium and Giardia were
found in the majority of raw water
sources, but calculation of their log
removal was limited by the
concentration present. River sources
had a higher incidence of pathogen
occurrence. Direct filtration plants had
higher levels of pathogens in the filtered
water than others in the survey.
Nearly all of the filter runs evaluated
in the survey exhibited spikes where
filtered water particle counts increased,
and pilot work showed that pathogens
are more likely to be released during
these spike events. Cryptosporidium
removal in the pilot scale spiking study
averaged nearly 4 log, regardless of the
influent oocyst concentration. Pilot
study results indicated a strong
relationship between removal of
Cryptosporidium and removal of
particles (> 3 \im] during runs using
optimal coagulation and similar
temperatures.
Patania et al (1999) evaluated
removal of Cryptosporidium at varied
raw water and filter effluent turbidity
levels using direct filtration. Runs were
conducted with both low (2 NTU) and
high (10 NTU) raw water turbidity.
Targeted filtered water turbidity was
either 0.02 or 0.05 NTU. At equivalent
filtered water turbidity,
Cryptosporidium removal was slightly
higher when the raw water turbidity
was higher. Also, Cryptosporidium
removal was enhanced by an average of
1.5 log when steady-state filtered water
turbidity was 0.02 NTU compared to
0.05 NTU.
Huck et al. (2000) evaluated filtration
efficiency during optimal and
suboptimal coagulation conditions with
two pilot scale filtration plants. One
plant employed a high coagulation dose
for both total organic carbon (TOC) and
particle removal, and the second plant
used a low dose intended for particle
removal only. Under optimal operating
conditions, which were selected to
achieve filtered water turbidity below
0.1 NTU, median Cryptosporidium
removal was 5.6 log at the high
coagulant dose plant and 3 log at the
low dose plant. Under suboptimal
coagulation conditions, where the
coagulant dose was reduced to achieve
filtered water turbidity of 0.2 to 0.3
NTU, median Cryptosporidium
removals dropped to 3.2 log and 1 log
at the high dose and low dose plants,
respectively. Oocyst removal also
decreased substantially at the end of the
filter cycle, although this was not
always indicated by an increase in
turbidity. Runs conducted with no
coagulant resulted in very little
Cryptosporidium removal.
Emelko et al. (2000) investigated
Cryptosporidium removal during
vulnerable filtration periods using a
pilot scale direct filtration system. The
authors evaluated four different
operational conditions: stable, early
breakthrough, late breakthrough, and
end of run. During stable operation,
effluent turbidity was approximately
0.04 NTU and Cryptosporidium removal
ranged from 4.7 to 5.8 log. In the early
breakthrough period, effluent turbidity
increased from approximately 0.04 to
0.2 NTU, and Cryptosporidium removal
decreased significantly, averaging 2.1
log. For the late breakthrough period,
where effluent turbidity began at
approximately 0.25 NTU and ended at
0.35 NTU, Cryptosporidium removal
dropped to an average of 1.4 log. Two
experiments tested Cryptosporidium
removal during the end-of-run
operation, when effluent turbidities
generally start increasing. Turbidity
started at about 0.04 NTU for both
experiments and ended at 0.06 NTU for
the first experiment and 0.13 NTU for
the second. Reported Cryptosporidium
removal ranged from 1.8 to 3.3 log, with
an average of 2.5 log for both
experiments.
Harrington et al. (2001) studied the
removal of Cryptosporidium and
emerging pathogens by filtration,
sedimentation, and dissolved air
flotation (DAF) using bench scale jar
tests and pilot scale conventional
treatment trains. In the bench scale
experiments, all run at optimized
coagulant doses, mean log removal of
Cryptosporidium was 1.2 by
sedimentation and 1.7 by DAF.
Cryptosporidium removal was similar in
all four water sources that were
evaluated and was not significantly
affected by lower pH or coagulant aid
addition. However, removal of
Cryptosporidium was greater at 22°C
than at 5°C, and was observed to be
higher with alum coagulant than with
either polyaluminum
hydroxychlorosulfate or ferric chloride.
In the pilot scale experiments, mean
log removal of Cryptosporidium was 1.9
in filtered water with turbidity of 0.2
NTU or less. Removal increased as
filtered water turbidity dropped below
0.3 NTU. There was no apparent effect
of filtration rate on removal efficiency.
In comparing Cryptosporidium removal
by sand, dual media (anthracite/sand),
and trimedia (anthracite/sand/garnet)
filters, no difference was observed near
neutral pH. However, at pH 5.7, removal
increased significantly in the sand filter
and it outperformed the other filter
media configurations. The authors
found no apparent explanation for this
behavior. There was no observable effect
of a turbidity spike on Cryptosporidium
removal.
Significance of Conventional and Direct
Filtration Studies
The performance of treatment plants
under current regulations is a significant
factor in determining the need for
additional treatment. As described in
section IV.A, the proposed
Cryptosporidium treatment
requirements associated with
LT2ESWTR risk bins for filtered systems
are based, in part, on an estimate that
conventional plants in compliance with
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the IESWTR achieve an average of 3 log
Cryptosporidium removal. The
following discussion illustrates why
EPA believes that available data support
this estimate.
While Cryptosporidium removal at
full scale plants is difficult to quantify
due to limitations with analytical
methods, pilot scale studies show that
reductions in aerobic spores and total
particle counts are often conservative
indicators of filtration plant removal
efficiency for Cryptosporidium (Dugan
etal 2001, McTigue etal. 1998, Yates
etal. 1998, Emelko eiaJ. 1999 and
2000). Surveys of full scale plants have
reported average reductions near 3 log
for both aerobic spores (Nieminski and
Bellamy, 2000) and total particle counts
(McTigue et al 1998). Consequently,
these findings are consistent with an
estimate that average removal of
Cryptosporidium by filtration plants is
approximately 3 log.
Pilot scale Cryptosporidium spiking
studies (Dugan et al. 2001, Huck et al.
2000, Emelko et al. 2000, McTigue et a].
1998, Patania et al 1995) suggest that a
conventional treatment plant has the
potential to achieve greater than 5 log
removal of Cryptosporidium under
optimal conditions. However, these high
removals are typically observed at very
low filter effluent turbidity values, and
the data show that removal efficiency
can decrease substantially over the
course of a filtration cycle or if
coagulation is not optimized (Dugan et
al 2001, Huck et al 2000, Emelko et al
2000, Harrington et al 2001). Removal
efficiency also appears to be impacted
by source water quality (Dugan et al
2001, McTigue et al 1998). Given these
considerations, EPA believes that 3 log
is a reasonable estimate of average
Cryptosporidium removal efficiency for
conventional treatment plants in
compliance with the IESWTR or
LT1ESWTR.
The Stage 2 M-DBP Advisory
Committee did not address direct
filtration plants, which lack the
sedimentation basin of a conventional
treatment train, but recommended that
EPA address these plants in the
LT2ESWTR proposal (65 FR 83015,
December 29, 2000) (USEPA 2000a).
While some studies have observed
similar levels of Cryptosporidium
removal in direct and conventional
filtration plants (Nieminski and
Ongerth, 1995, Ongerth and Pecoraro
1995), EPA has concluded that the
majority of available data support a
lower estimate of Cryptosporidium
removal efficiency for direct filtration
plants.
As described in section IV.C.5, pilot
and full scale studies demonstrate that
sedimentation basins, which are absent
in direct filtration, can achieve 0.5 log
or greater Cryptosporidium reduction
(Dugan et al 2001, Patania et al 1995,
Edzwald and Kelly 1998, Payment and
Franco 1993, Kelley et al 1995). In
addition, Patania et a]. (1995) observed
direct filtration to achieve less
Cryptosporidium removal than
conventional treatment, and McTigue et
al (1998) found a higher incidence of
Cryptosporidium in the treated water of
direct filtration plants. Given these
findings, EPA has estimated that direct
filtration plants achieve an average of
2.5 log Cryptosporidium reduction (i.e.,
0.5 log less than conventional
treatment).
i. Dissolved air flotation. Dissolved air
flotation (DAF) is a solid-liquid
separation process that can be used in
conventional treatment trains in place of
gravity sedimentation. DAF takes
advantage of the buoyancy of oocysts by
floating oocyst/particle complexes to the
surface for removal. In DAF, air is
dissolved in pressurized water, which is
then released into a flotation tank
containing flocculated particles. As the
water enters the tank, the dissolved air
forms small bubbles that collide with
and attach to floe particles and float to
the surface (Gregory and Zabel, 1990).
In comparing DAF with gravity
sedimentation, Plummer et al (1995)
observed up to 0.81 log removal of
oocysts in the gravity sedimentation
process, while DAF achieved 0.38 to 3.7
log removal, depending on coagulant
dose. Edzwald and Kelley (1998)
demonstrated a 3 log removal of oocysts
using DAF, compared with a 1 log
removal using gravity sedimentation in
the clarification process before
filtration. In bench scale testing by
Harrington et al (2001), DAF averaged
0.5 log higher removal of
Cryptosporidium than gravity
sedimentation. Based on these results,
EPA has concluded that a treatment
plant using DAF plus filtration can
achieve levels of Cryptosporidium
removal equivalent to or greater than a
conventional treatment plant with
gravity sedimentation.
b. Slow sand filtration. Slow sand
filtration is a process involving passage
of raw water through a bed of sand at
low velocity (generally less than 0.4 m/
h) resulting in substantial particulate
removal by physical and biological
mechanisms. For the LT2ESWTR
proposal, EPA has reviewed two
additional studies of slow sand
filtration.
Fogel et al (1993) evaluated removal
efficiencies for Cryptosporidium and
Giardia with a full scale slow sand
filtration plant. The removals ranged
from 0.1-0.5 log for Cryptosporidium
and 0.9-1.4 log for Giardia. Raw water
turbidity ranged from 1.3 to 1.6 NTU
and decreased to 0.35-0.31 NTU after
filtration. The authors attributed the low
Cryptosporidium and Giardia removals
to the relatively poor grade of filter
media and lower water temperature.
The sand had a higher uniformity
coefficient than recommended by design
standards. This creates larger pore
spaces within the filter bed that retard
biological removal capacity. Lower
water temperatures (1 °C) also decreased
biological activity in the filter media.
Hall et al (1994) examined the
removal of Cryptosporidium with a pilot
scale slow sand filtration plant.
Cryptosporidium removals ranged from
2.8 to 4.3 log after filter maturation,
with an average of 3.8 log (at least one
week after filter scraping). Raw water
turbidity ranged from 3.0 NTU to 7.5
NTU for three of four runs and 15.0
NTU for a fourth run. Filtered water
turbidity was 0.2 to 0.4 NTU, except for
the fourth run which had 2.5 NTU
filtered water turbidity. This study also
included an investigation of
Cryptosporidium removal during filter
start-up where the filtration rate was
slowly increased over a 4 day period.
Results indicate that filter ripening did
not appear to affect Cryptosporidium
removal.
The study by Fogel et al is significant
because it indicates that a slow sand
filtration plant may achieve less than 2
log removal of Cryptosporidium removal
while being in compliance with the
effluent turbidity requirements of the
IESWTR and LTlESWTR. The authors
attributed this poor performance to the
filter being improperly designed, which,
if correct, illustrates the importance of
proper design for removal efficiency in
slow sand filters. In contrast, the study
by Hall et al (1994) supports other work
(Schuler and Ghosh 1991, Timms et al
1995) in finding that slow sand filtration
can achieve Cryptosporidium removal
greater than 3 log. Overall, this body of
work appears to show that slow sand
filtration has the potential to achieve
Cryptosporidium removal efficiencies
similar to that of a conventional plant,
but proper design and operation are
critical to realizing treatment goals.
c. Diatomaceous earth filtration.
Diatomaceous earth filtration is a
process in which a precoat cake of filter
media is deposited on a support
membrane and additional filter media is
continuously added to the feed water to
maintain the permeability of the filter
cake. Since the IESWTR and
LTlESWTR, EPA has reviewed one new
study of DE filtration (Ongerth and
Hutton 2001). It supports the findings of
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47663
earlier studies (Schuler and Gosh 1990,
Ongerth and Hutton 1997) in showing
that a well designed and operated DE
plant can achieve Cryptosporidium
removal equivalent to a conventional
treatment plant (i.e., average of 3 log).
d. Other filtration technologies. In
today's proposal, information about bag
filters, cartridge filters, and membranes,
including criteria for awarding
Cryptosporidium treatment credit, is
presented in section IV.C as part of the
microbial toolbox. Section IV.C also
addresses credit for pretreatment
options like presedimentation basins
and bank filtration.
e. Inactivation. Substantial advances
in understanding of Cryptosporidium
inactivation by ozone, chlorine dioxide,
and UV have been made following the
IESWTR and LT1ESWTR. These
advances have allowed EPA to develop
criteria to award Cryptosporidium
treatment credit for these disinfectants.
Relevant information is summarized
next, with additional information
sources noted.
i. Ozone and chlorine dioxide. With
the completion of several major studies,
EPA has acquired sufficient information
to develop standards for the inactivation
of Cryptosporidium by ozone and
chlorine dioxide. For both of these
disinfectants, today's proposal includes
CT tables that specify a level of
Cryptosporidium treatment credit based
on the product of disinfectant
concentration and contact time.
For ozone, the CT tables in today's
proposal were developed through
considering four sets of experimental
data: Li et al (2001), Owens et al.
(2000), Oppenheimer et al (2000), and
Rennecker et al. (1999). Chlorine
dioxide CT tables are based on three
experimental data sets: Li et al. (2001),
Owens et al. (1999), and Ruffell et al.
(2000). Together these studies provide a
large body of data that covers a range of
water matrices, both laboratory and
natural. While the data exhibit
variability, EPA believes that
collectively they are sufficient to
determine appropriate levels of
treatment credit as a function of
disinfection conditions. CT tables for
ozone and chlorine dioxide inactivation
of Cryptosporidium are presented in
Section IV.C.14 of this preamble.
ii. Ultraviolet light. A major recent
development is the finding that UV light
is highly effective for inactivating
Cryptosporidium and Giardia at low
doses. Research prior to 1998 had
indicated that very high doses of UV
light were required to achieve
substantial disinfection of protozoa.
However, as noted previously, these
results were largely based on the use of
in vitro assays, which were later shown
to substantially overestimate the UV
doses required to prevent infection
(Clancy et al. 1998, Bukhari et al. 1999,
Craik et al. 2000). Recent research using
in vivo assays (e.g., neonatal mouse
infectivity) and cell culture techniques
to measure infectivity has provided
strong evidence that both
Cryptosporidium and Giardia are highly
sensitive to low doses of UV.
BILLING CODE 6560-50-P
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Figure III-5.-- Inactivation of Cryptosporidium by UV Light
BILLING CODE 6560-50-C
Figure III-5 presents data from
selected studies of UV inactivation of
Cryptosporidium. While the data in
Figure III-5 show substantial scatter,
they are consistent in demonstrating a
high level of inactivation at relatively
low UV doses. These studies generally
demonstrated at least 3 log
Cryptosporidium inactivation at UV
doses of 10 mJ/cm 2 and higher. In
comparison, typical UV dose for
drinking water disinfection are 30 to 40
mJ/cm 2. A recent investigation by
Clancy et al. (2002) showed that UV
light at 10 mJ/cm2 provided at least 4
log inactivation of five strains of
Cryptosporidium that are infectious to
humans. Studies of UV inactivation of
Giardia have reported similar results
(Craik et al. 2000, Mofidi etal. 2002,
Linden et al 2002, Campbell and Wallis
2002, Hayes etal 2003).
In addition to efficacy for protozoa
inactivation, data indicate that UV
disinfection does not promote the
formation of DBFs (Malley et al. 1995,
Zheng et al 1999). Malley et al (1995)
evaluated DBF formation in a number of
surface and ground waters with UV
doses between 60 and 200 mJ/cm2. UV
light did not directly form DBFs, such
as trihalomethanes (THM) and
haloacetic acids (HAA), and did not
alter the concentration or species of
DBFs formed by post-disinfection with
chlorine or chloramines. A study by
Zheng et al (1999) reported that
applying UV light following chlorine
disinfection had little impact on THM
and HAA formation. In addition, data
suggest that photolysis of nitrate to
nitrite, a potential concern with certain
types of UV lamps, will not result in
nitrite levels near the MCL under
typical drinking water conditions
(Feldszus et al 2000, Sharp less and
Linden 2001).
These studies demonstrate that UV
light is an effective technology for
inactivating Ciardia and
Cryptosporidium, and that it does not
form DBFs at levels of concern in
drinking water. Section IV.G.15
describes proposed criteria for awarding
treatment credit for UV inactivation of
Cryptosporidium, Giardia lamblia, and
viruses. These criteria include UV dose
tables, validation testing, and
monitoring standards. In addition, EPA
is preparing a UV Disinfection Guidance
Manual with information on design,
testing, and operation of UV systems. A
draft of this guidance is available in the
docket for today's proposal (http://
www.epa.gov/edocket/).
iii. Significance of new information
on inactivation. The research on ozone,
chlorine dioxide, and UV light
described in this proposal has made
these disinfectants available for systems
to use in meeting additional
Cryptosporidium treatment
requirements under LT2ESWTR. This
overcomes a significant limitation to
establishing inactivation requirements
for Cryptosporidium that existed when
the IESWTR was developed. The Stage
1 Advisory Committee recognized the
need for inactivation criteria if EPA
were to consider a risk based proposal
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47665
for Cryptosporidium in future
rulemaking (62 FR 59498, November 3,
1997) (USEPA 2000b). The CT tables for
ozone and chlorine dioxide provide
such criteria. In addition, the
availability of UV furnishes another
relatively low cost tool to achieve
Cryptosporidium inactivation and DBF
control.
While no single treatment technology
is appropriate for all systems, EPA
believes that these disinfectants, along
with the other management and
treatment options in the microbial
toolbox presented in section IV.C, make
it feasible for systems to meet the
additional Cryptosporidium treatment
requirements in today's proposal.
IV. Discussion of Proposed LT2ESWTR
Requirements
A. Additional Cryptosporidium
Treatment Technique Requirements for
Filtered Systems
1. What Is EPA Proposing Today?
a. Overview of framework approach.
EPA is proposing treatment technique
requirements to supplement the existing
requirements of the SWTR, IESWTR,
and LT1ESWTR (see section II.B). The
proposed requirements will achieve
increased protection against
Cryptosporidium in public water
systems that use surface water or ground
water under the direct influence of
surface water as sources. Under this
proposal, filtered systems will be
assigned to one of four risk categories
(or "bins"), based on the results of
source water Cryptosporidium
monitoring. Systems assigned to the
lowest risk bin incur no additional
treatment requirements, while systems
assigned to higher risk bins must reduce
Cryptosporidium levels beyond IESWTR
and LT1ESWTR requirements. Systems
will comply with additional
Cryptosporidium treatment
requirements by selecting treatment and
management strategies from a
"microbial toolbox" of control options.
Today's proposal reflects
recommendations from the Stage 2 M-
DBP Federal Advisory Committee (65
FR 83015, December 29, 2000) (USEPA
2000a), which described this approach
as a "microbial framework". This
approach targets additional treatment
requirements to those systems with the
highest source water Cryptosporidium
leveis and, consequently, the highest
vulnerability to this pathogen. In so
doing, today's proposal builds upon the
current treatment technique
requirement for Cryptosporidium under
which all filtered systems must achieve
at least a 2 log reduction, regardless of
source water quality. The intent of this
proposal is to assure that public water
systems with the higher risk source
water achieve a level of public health
protection commensurate with systems
with less contaminated source water.
b. Monitoring requirements. Today's
proposal requires systems to monitor
their source water {influent water prior
to treatment plant) for Cryptosporidium,
E. coli, and turbidity. The purpose of the
monitoring is to assess source water
Cryptosporidium levels and, thereby,
classify systems in different risk bins.
Proposed monitoring requirements for
large and small systems are summarized
in Table IV-I and are characterized in
the following discussion.
Large Systems
Large systems (serving at least 10,000
people) must sample their source water
at least monthly for Cryptosporidium, E.
coli, and turbidity for a period of 2
years, beginning no later than 6 months
after LT2ESWTR promulgation. Systems
may sample more frequently (e.g., twice-
per-month, once-per-week), provided
the same sampling frequency is used
throughout the 2-year monitoring
period. As described in section IV.A.l.c,
systems that sample more frequently (at
least twice-per-month) use a different
calculation that is potentially less
conservative to determine their bin
classification.
The purpose of requiring large
systems to collect E. coli and turbidity
data is to further evaluate these
parameters as indicators to identify
drinking water sources that are
susceptible to high concentrations of
Cryptosporidium. As described next,
these data will be applied to small
system LT2ESWTR monitoring.
Small Systems
EPA is proposing a 2-phase
monitoring strategy for small systems
(serving fewer than 10,000 people) to
reduce their monitoring burden. This
approach is based on Information
Collection Rule and ICRSS data
indicating that systems with low source
water E. coli levels are likely to have
low Cryptosporidium levels, such that
additional treatment would not be
required under the LT2ESWTR. Under
this approach, small systems must
initially conduct one year of bi-weekly
sampling (one sample every two weeks)
for E. coli, beginning 2.5 years after
LT2ESWTR promulgation. Small
systems are triggered into
Cryptosporidium monitoring only if the
initial E. coli monitoring indicates a
mean concentration greater than 10 E.
coli/IQQ mL for systems using a
reservoir or lake as their primary source
or greater than 50 E. coli/WO mL for
systems using a flowing stream as their
primary source. Small systems that
exceed these E. coli trigger values must
conduct one year of twice-per-month
Cryptosporidium sampling, beginning 4
years after LT2ESWTR promulgation.
The analysis supporting the proposed
E. coli values that trigger
Cryptosporidium monitoring by small
systems is presented in Section IV.A.2.
However, as recommended by the Stage
2 M-DBP Advisory Committee, EPA
will evaluate Cryptosporidium indicator
relationships in the LT2ESWTR
monitoring data collected by large
systems. If these data support the use of
different indicator levels to trigger small
system Cryptosporidium monitoring,
EPA will issue guidance with
recommendations. The proposed
LT2ESWTR allows States to specify
alternative indicator values for small
systems, based on EPA guidance.
TABLE IV-1.—LT2ESWTR MONITORING REQUIREMENTS
Public water systems
Large systems (serving
10,000 or more people).
Small systems (serving
fewer than 10,000 peo-
ple).
Monitoring begins
6 months after promul-
gation of
LT2ESWTR3.
30 months (2% years)
after promulgation of
LT2ESWTR.
Monitoring dura-
tion
Monitoring parameters and sample frequency requirements
Cryptosporidium
minimum 1 sample/
month b.
See following rows
E. coli
minimum 1 sam-
ple/month1".
1 sample every
two weeks.
Turbidity
minimum 1 measure-
ment/month1'.
N/A
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TABLE IV-1.—LT2ESWTR MONITORING REQUIREMENTS—Continued
Public water systems
Monitoring begins
Monitoring dura-
tion
Monitoring parameters and sample frequency requirements
Cryptosporidium
E. coli
Turbidity
Small systems (serving
fewer than 10,000 peo-
Ple)e-
48 months (4 years)
after promulgation of
LT2ESWTR.
N/A
N/A.
N/A = Not applicable. No monitoring required.
Sampling Location
Source water samples must be
representative of the intake to the
filtration plant. Generally, sampling
must be performed individually for each
plant that treats a surface water source.
However, where multiple plants receive
all of their water from the same influent
(e.g., multiple plants draw water from
the same pipe), the same set of
monitoring results may be applicable to
each plant. Typically, samples must be
collected prior to any treatment, with
exceptions for certain pretreatment
processes. Directions on sampling
location for plants using off-stream
storage, presedimentation, and bank
filtration are provided in section IV.C.
Systems with plants that use multiple
water sources at the same time must
collect samples from a tap where the
sources are combined prior to treatment
if available. If a blended source tap is
not available, systems must collect
samples from each source and either
analyze a weighted composite (blended)
sample or analyze samples from each
source separately and determine a
weighted average of the results.
Sampling Schedule
Large systems must submit a sampling
schedule to EPA within 3 months after
promulgation of the LT2ESWTR. Small
systems must submit a sampling
schedule for E. coli monitoring to their
primacy agency within 27 months after
rule promulgation; small systems
required to monitor for Cryptosporidium
must submit a Cryptosporidium
sampling schedule within 45 months
after promulgation. The sampling
schedules must specify the calendar
date on which the system will collect
each sample required under the
LT2ESWTR. Scheduled sampling dates
should be evenly distributed throughout
the monitoring period, but may be
arranged to accommodate holidays,
weekends, and other events when
collecting or analyzing a sample would
be problematic.
Systems must collect samples within
2 days before or 2 days after a scheduled
sampling date. If a system does not
sample within this 5-day window, the
system will incur a monitoring violation
unless either of the following two
conditions apply:
(1) If extreme conditions or situations exist
that may pose danger to the sample collector,
or which are unforeseen or cannot be avoided
and which cause the system to be unable to
sample in the required time frame, the
system must sample as close to the required
date as feasible and submit an explanation
for the alternative sampling date with the
analytical results.
(2) Systems that are unable to report a valid
Cryptosporidium analytical result for a
scheduled sampling date due to failure to
comply with analytical method quality
control requirements (described in section
IV.K) must collect a replacement sample
within 14 days of being notified by the
laboratory or the State that a result cannot be
reported for that date. Systems must submit
an explanation for the replacement sample
with the analytical results. Where possible,
the replacement sample collection date
should not coincide with any other
scheduled LT2ESWTR sampling dates.
Approved Analytical Methods and
Laboratories
To ensure the quality of LT2ESWTR
monitoring data, today's proposal
requires systems to use approved
methods for Cryptosporidium, E. coli,
and turbidity analyses (see section IV.K
for sample analysis requirements), and
to have these analyses performed by
approved laboratories (described in
section IV.L).
Reporting
Because source water monitoring by
large systems will begin 6 months after
promulgation of the LT2ESWTR, EPA is
proposing that monitoring results for
large systems be reported directly to the
Agency though an electronic data
system (described in section 1V.J),
similar to the approach currently used
under the Unregulated Contaminants
Monitoring Rule (64 FR 50555,
September 17,1999) (USEPA 1999c).
Small systems will report data to EPA
or States, depending on whether States
have assumed primacy for the
LT2ESWTR.
Previously Collected Monitoring Results
EPA is proposing to allow systems to
use previously collected (i.e.,
grandfathered) Cryptosporidium
monitoring data to meet LT2ESWTR
monitoring requirements if the data are
equivalent to data that will be collected
under the rule (e.g., sample volume,
sampling frequency, analytical method
quality control). Criteria for acceptance
of previously collected data are
specified in section IV.A.l.d.
Providing Additional Treatment Instead
of Monitoring
Filtered systems are not required to
conduct source water monitoring under
the LT2ESWTR if the system currently
provides or will provide a total of at
least 5.5 log of treatment for
Cryptosporidium, equivalent to meeting
the treatment requirements of Bin 4 as
shown in Table IV-4 (i.e., the maximum
required in today's proposal). Systems
must notify EPA or the State not later
than the date the system is otherwise
required to submit a sampling schedule
for monitoring and must install and
operate technologies to provide a total
of at least 5.5 log of treatment for
Cryptosporidium by the applicable date
in Table 1V-23. Any filtered system that
fails to complete LT2ESWTR monitoring
requirements must meet the treatment
requirements for Bin 4.
Ongoing Source Assessment and Second
Round of Monitoring
Because LT2ESWTR treatment
requirements are related to the degree of
source water contamination, today's
proposal contains provisions to assess
changes in a system's source water
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47667
quality following initial risk bin
classification. These provisions include
source water assessment during sanitary
surveys and a second round of
monitoring.
Under 40 CFR 142.16(b)(3)(i), source
water is one of the components that
States must address during the sanitary
surveys that are required for surface
water systems. These sanitary surveys
must be conducted every 3 years for
community systems and every 5 years
for non-community systems. EPA is
proposing that if the State determines
during the sanitary survey that
significant changes have occurred in the
watershed that could lead to increased
contamination of the source water, the
State may require systems to implement
specific actions to address the
contamination. These actions include
implementing options from the
microbial toolbox discussed in section
IV.C.
EPA is proposing that systems
conduct a second round of source water
monitoring, beginning six years after
systems are initially classified in
LT2ESWTR risk bins. To prepare for
this second round of monitoring, the
Advisory Committee recommended that
EPA initiate a stakeholder process four
years after large systems complete initial
bin classification. The purpose of the
stakeholder process would be to review
risk information, and to determine the
appropriate analytical method,
monitoring frequency, monitoring
location, and other criteria for the
second round of monitoring.
If EPA does not modify LT2ESWTR
requirements through issuing a new
regulation prior to the second round of
monitoring, systems must carry out this
monitoring according to the
requirements that apply to the initial
round of source water monitoring.
Moreover, systems will be reclassified
in LT2ESWTR risk bins based on the
second round monitoring results and
using the criteria specified in this
section for initial bin classification.
However, if EPA changes the
LT2ESWTR risk bin structure to reflect
a new analytical method or new risk
information, systems will undergo a site
specific risk characterization in
accordance with the revised rule.
c. Treatment Requirements
i. Bin classification. Under the
proposed LT2ESWTR, surface water
systems that use filtration will be
classified in one of four
Cryptosporidium concentration
categories (bins) based on the results of
source water monitoring. As shown in
Table IV-2, bin classification is
determined by averaging the
Cryptosporidium concentrations
measured for individual samples.
TABLE IV-2.— BIN CLASSIFICATION
TABLE FOR FILTERED SYSTEMS
If your average
Cryptosporidium con-
centration ' is . . .
Cryptosporidium <0.075/L
0.075/L < Cryptosporidium
< 1.0/L.
1.0/L < Cryptosporidium <
3.0/L.
Cryptosporidium > 3.0/L ...
Then your bin
classification is
Bin 1.
Bin 2.
Bin 3.
Bin 4.
1 All concentrations shown in units of
oocysts/L
The approach that systems wil! use to
average individual sample
concentrations to determine their bin
classification depends on the number of
samples collected and the length of the
monitoring period. Systems serving at
least 10,000 people are required to
monitor for 24 months, and their bin
classification must be based on the
following:
(1) Highest twelve month running
annual average for monthly sampling, or
{2} two year mean if system conducts
twice-per-month or more frequent
sampling for 24 months (i.e., at least 48
samples).
Systems serving fewer than 10,000
people are required to collect 24
Cryptosporidium samples over 12
months if they exceed the E. coli trigger
level, and their bin classification must
be based on the mean of the 24 samples.
As noted earlier, systems that fail to
complete the required Cryptosporidium
monitoring will be classified in Bin 4.
When determining LT2ESWTR bin
classification, systems must calculate
individual sample concentrations using
the total number of oocysts counted,
unadjusted for method recovery,
divided by the volume assayed (see
section IV.K for details). As described in
Section IV.A.2, the ranges of
Cryptosporidium concentrations that
define LT2ESWTR bins reflect
consideration of analytical method
recovery and the percent of
Cryptosporidium oocysts that are
infectious. Consequently, sample
analysis results will not be adjusted for
these factors.
ii. Credit for treatment in place. A key
parameter in determining additional
Cryptosporidium treatment
requirements is the credit that plants
receive for treatment currently provided
(i.e., treatment in place). For baseline
treatment requirements established by
the SWTR, IESWTR, and LT1ESWTR
that apply uniformly to filtered systems,
the Agency has awarded credit based on
the minimum removal that plants will
achieve. Specifically, in the IESWTR
and LT1ESWTR, EPA determined that
filtration plants, including
conventional, direct, slow sand, and DE,
meeting the required filter effluent
turbidity criteria will achieve at least 2
log removal of Cryptosporidium.
Consequently, these plants were
awarded a 2 log Cryptosporidium
removal credit, which equals the
maximum treatment required under
these regulations.
The LT2ESWTR will supplement
existing regulations by mandating
additional treatment at certain plants
based on site specific conditions (i.e.,
source water Cryptosporidium level).
When assessing the need for additional
treatment beyond baseline requirements
for higher risk systems, the Agency has
determined that it is appropriate to
consider the average removal efficiency
achieved by treatment plants. As
described in section III.D, EPA has
concluded that conventional, slow sand,
and DE plants in compliance with the
SWTR, IESWTR, and LTlESWTR
achieve an average Cryptosporidium
reduction of 3 log. Consequently, EPA is
proposing to award these plants a 3 log
credit towards Cryptosporidium
treatment requirements under the
LT2ESWTR. As noted previously, this
approach is consistent with the Stage 2
M-DBP Agreement in Principle.
For other types of filtration plants,
treatment credit under the LT2ESWTR
differs. Conventional treatment is
defined in 40 CFR 141.2 as a series of
processes including coagulation,
flocculation, sedimentation, and
filtration, with sedimentation defined as
a process for removal of solids before
filtration by gravity or separation. Thus,
plants with separation (i.e.,
clarification) processes other than
gravity sedimentation between
flocculation and filtration, such as DAF,
may be regarded as conventional
treatment for purposes of awarding
treatment credit under the LT2ESWTR.
However, for direct filtration plants,
which lack a sedimentation process,
EPA is proposing a 2.5 log
Cryptosporidium removal credit.
Studies that support awarding direct
filtration plants less treatment credit
than conventional plants are
summarized in section III.D.
EPA is unable to estimate an average
log removal for other filtration
technologies like membranes, bag filters,
and cartridge filters, due to variability
among products. As a result, credit for
these devices must be determined by the
State, based on product specific testing
described in section IV.C or other
criteria approved by the State.
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Table IV-3 presents the credit
proposed for different types of plants
towards LT2ESWTR Cryptosporidium
treatment requirements. As described in
section IV.C.18, a State may award
greater credit to a system that
demonstrates through a State-approved
protocol that it reliably achieves a
higher level of Cryptosporidium
removal. Conversely, a State may award
less credit to a system where the State
determines, based on site specific
information, that the system is not
achieving the degree of
Cryptosporidium removal indicated in
Table IV-3.
TABLE IV-3.—Cryptosporidium TREATMENT CREDIT TOWARDS LT2ESWTR REQUIREMENTS'
Plant type
Treatment credit
Conventional treatment (in-
cludes softening)
3.0 log
Direct filtration
2.5 log
Slow sand or diatoma-
ceous earth filtration
3.0 log
Alternative filtration tech-
nologies
Determined by State2.
| Applies to plants in full compliance with the SWTR, IESWTR, and LT1ESWTR as applicable
2 Credit must be determined through product or site specific assessment
iii. Treatment requirements associated
with LT2ESWTR bins
The treatment requirements
associated with LT2ESWTR risk bins are
shown in Table IV-4. The total
Cryptosporidium treatment required for
Bins 2, 3, and 4 is 4.0 log, 5.0 log, and
5.5 log, respectively. For conventional
(including softening), slow sand, and DE
plants that receive 3.0 log credit for
compliance with current regulations,
additional Cryptosporidium treatment of
1.0 to 2.5 log is required when classified
in Bins 2-4. Direct filtration plants that
receive 2.5 log credit for compliance
with current regulations must achieve
1.5 to 3.0 log of additional
Cryptosporidium treatment in Bins 2-4.
For systems using alternative
filtration technologies, such as
membranes or bag/cartridge filters, and
classified in Bins 2-4, the State must
determine additional treatment
requirements based on the credit
awarded to a particular technology. The
additional treatment must be such that
plants classified in Bins 2, 3, and 4
achieve the total required
Cryptosporidium reductions of 4.0, 5.0,
and 5.5 log, respectively.
TABLE IV-4.—TREATMENT REQUIREMENTS PER LT2ESWTR BIN CLASSIFICATION
If your bin classi-
fication is ...
Bin 1
Bin 2
And you use the following filtration treatment in full compliance with the SWTR, IESWTR, and LT1ESWTR (as applica-
ble), then your additional treatment requirements are ...
Conventionat filtration treat-
ment (includes softening)
No additional treatment
1 log treatment 1
Direct filtration
No additional treatment
2.5 log treatment2
Slow sand or diatomaceous
earth filtration
No additional treatment
2 log treatment2
2.5 log treatment2
Alternative filtration tech-
nologies
No additional treatment.
As determined by the
State1-3.
As determined by the
State 2- ".
As determined by the
State 2. 5.
mav use any technology or combination of technologies from the microbial toolbox.
must achieve at least 1 log of the required treatment using ozone, chlorine dioxide, UV, membranes, bag/cartridge fitters, or bank fil-
3Totat Cryptosporidium removal and inactivation must be at least 4.0 tog.
"Total Cryptosporidium removal and inactivation must be at least 5.0 log.
5Total Cryptosporidium removal and inactivation must be at least 5.5 log.
Plants can achieve additional
Cryptosporidium treatment credit
through implementing pretreatment
processes like presedimentation or bank
filtration, by developing a watershed
control program, and by applying
additional treatment steps like UV,
ozone, chlorine dioxide, and
membranes. In addition, plants can
receive additional credit for existing
treatment through achieving very low
filter effluent turbidity or through a
demonstration of performance. Section
IV.C presents criteria for awarding
Cryptosporidium treatment credit to a
host of treatment and control options,
including those listed here and others,
which are collectively termed the
"microbial toolbox".
Systems in Bin 2 can meet additional
Cryptosporidium treatment
requirements through using any option
or combination of options from the
microbial toolbox. In Bins 3 and 4,
systems must achieve at least 1 log of
the additional treatment requirement
through using ozone, chlorine dioxide,
UV, membranes, bag filtration, cartridge
filtration, or bank filtration.
d. Use of previously collected data.
Today's proposal allows systems with
previously collected Cryptosporidium
data (i.e., data collected prior to the
required start of monitoring under the
LT2ESWTR) that are equivalent in
sample number, frequency, and data
quality to data that will be collected
under the LT2ESWTR to use those data
in lieu of conducting new monitoring.
Specifically, EPA is proposing that
Cryptosporidium sample analysis
results collected prior to promulgation
of the LT2ESWTR must meet the
following criteria to be used for bin
classification:
• Samples were analyzed by
laboratories using validated versions of
EPA Methods 1622 or 1623 and meeting
the quality control criteria specified in
these methods (USEPA 1999a, USEPA
1999b, USEPA 2001e, USEPA 2001f).
• Samples were collected no less
frequently than each calendar month on
a regular schedule, beginning no earlier
than January 1999 (when EPA Method
1622 was first released as an
interlaboratory-validated method).
• Samples were collected in equal
intervals of time over the entire
collection period (e.g., weekly,
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47669
monthly). The allowances for deviations
from a sampling schedule specified
under IV.A.l.b for LT2ESWTR
monitoring apply to grandfathered data.
• Samples were collected at the
correct location as specified for
LT2ESWTR monitoring. Systems must
report the use of bank filtration,
presedimentation, and raw water off-
stream storage during sampling.
• For each sample, the laboratory
analyzed at least 10 L of sample or at
least 2 mL of packet pellet volume or as
much volume as two filters could
accommodate before clogging (applies
only to filters that have been approved
by EPA for use with Methods 1622 and
1623).
• The system must certify that it is
reporting all Cryptosporidium
monitoring results generated by the
system during the time period covered
by the previously collected data. This
applies to samples that were (a)
collected from the sampling location
used for LT2ESWTR monitoring, (b) not
spiked, and (c) analyzed using the
laboratory's routine process for Method
1622 or 1623 analyses.
• The system must also certify that
the samples were representative of a
plant's source water(s) and the source
water(s) have not changed.
If a system has at least two years of
Cryptosporidium data collected before
promulgation of the LT2ESWTR and the
system does not intend to conduct new
monitoring under the rule, the system
must submit the data and the required
supporting documentation to EPA no
later than two months following
promulgation of the rule. EPA will
notify the system within four months
following LT2ESWTR promulgation as
to whether the data are sufficient for bin
determination. Unless EPA notifies the
system in writing that the previously
collected data are sufficient for bin
determination, the system must conduct
source water Cryptosporidium
monitoring as described in section
IV.A.l.b of this preamble.
If a system intends to grandfather
fewer than two years of
Cryptosporidium data, or if a system
intends to grandfather 2 or more years
of previously collected data and also to
conduct new monitoring under the rule,
the system must submit the data and the
required supporting documentation to
EPA no later than eight months
following promulgation of the rule.
Systems must conduct monitoring as
described in section IV.A.l.b until EPA
notifies the system in writing that it has
at least 2 years of acceptable data. See
section IV.J for additional information
on reporting requirements associated
with previously collected data.
2. How Was This Proposal Developed?
The monitoring and treatment
requirements for filtered systems
proposed under the LT2ESWTR stem
from the data and analyses described in
this section and reflect
recommendations made by the Stage 2
M-DBP Federal Advisory Committee
(65 FR 83015) (USEPA 2000a).
a. Basis for targeted treatment
requirements. Under the IESWTR, EPA
established an MCLG of zero for
Cryptosporidium at the genus level
based on the public health risk
associated with this pathogen. The
IESWTR included a 2 log treatment
technique requirement for medium and
large filtered systems that controlled for
Cryptosporidium as close to the MCLG
as was then deemed technologically
feasible, taking costs into consideration.
The LT1ESWTR extended this
requirement to small systems; Given the
advances that have occurred subsequent
to the IESWTR in available technology
to measure and treat for
Cryptosporidium, a key question for the
LT2ESWTR was the extent to which
Cryptosporidium should be further
controlled to approach the MCLG of
zero, considering technical feasibility,
costs, and potential risks from DBFs.
The data and analysis presented in
Section III of this preamble suggest wide
variability in possible risk from
Cryptosporidium among public water
systems. This variability is largely due
to three factors: (1) The broad
distribution of Cryptosporidium
occurrence levels among source waters,
(2) disparities in the efficacy of
treatment provided by plants, and (3)
differences in the infectivity among
Cryptosporidium isolates. EPA and the
Advisory Committee considered this
wide range of possible risks and the
desire to address systems where the 2
log removal requirement established by
the IESWTR and LTlESWTR may not
provide adequate public health
protection.
A number of approaches were
evaluated for furthering control of
Cryptosporidium. One approach was to
require all systems to provide the same
degree of additional treatment for
Cryptosporidium (i.e., beyond that
required by the IESWTR and
LTlESWTR). This approach could
ensure that most systems, including
those with poor quality source water,
would be adequately protective. The
uniformity of this approach has the
advantage of minimizing transactional
costs for determining what must be
done by a particular system to comply.
However, a significant downside is that
it may require more treatment, with
consequent costs, than is needed by
many systems with low source water
Cryptosporidium levels. In addition,
there were concerns with the feasibility
of requiring almost all surface water
treatment plants to install additional
treatment processes for
Cryptosporidium.
A second approach was to base
additional treatment requirements on a
plant's source water Cryptosporidium
level. Under this approach, systems
monitor their source water for
Cryptosporidium, and additional
treatment is required only from those
systems that exceed specified oocyst
concentrations. This has the advantage
of targeting additional public health
protection to those systems with higher
vulnerability to Cryptosporidium, while
avoiding the imposition of higher
treatment costs on systems with the
least contaminated source water. In
consideration of these advantages, the
Advisory Committee recommended and
EPA is proposing this second approach
for filtered systems under the
LT2ESWTR.
b. Basis for bin concentration ranges
and treatment requirements. The
proposed LT2ESWTR will classify
plants into different risk bins based on
the source water Cryptosporidium level,
and the bin classification will determine
the extent to which additional treatment
beyond IESWTR and LTlESWTR is
required. Two questions were central in
developing the proposed bin
concentration ranges and additional
treatment requirements:
• What is the risk associated with a
given level of Cryptosporidium in a
drinking water source?
• What degree of additional treatment
should be required for a given source
water Cryptosporidium level?
This section addresses these two
questions by first summarizing how
EPA assessed the risk associated with
Cryptosporidium in drinking water,
followed by a description of how EPA
and the Advisory Committee used this
type of information in identifying
LT2ESWTR bin concentration ranges
and treatment requirements. For
additional information on these topics,
see Economic Analysis for the
LT2ESWTR (USEPA 2003a).
i. What is the risk associated with a
given level of Cryptosporidium in a
drinking water source? The risk of
infection from Cryptosporidium in
drinking water is a function of
infectivity (i.e., dose-response
associated with ingestion) and exposure.
Section III.B summarizes available data
on Cryptosporidium infectivity. EPA
conducted a meta-analysis of reported
infection rates from human feeding
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studies with 3 Cryptosporidium isolates.
This analysis produced an estimate for
the mean probability of infection given
a dose of one oocyst near 0.09 (9%),
with 10th and 90th percentile
confidence values of 0.011 and 0.22,
respectively.
Exposure to Cryptosporidium
depends on the concentration of oocysts
in the source water, the efficiency of
treatment plants in removing oocysts,
and the volume of water ingested
(exposure can also occur through
interactions with infected individuals).
Based on data presented in section III.D,
EPA has estimated that filtration plants
in compliance with the IESWTR or
LT1ESWTR reduce source water
Cryptosporidium levels by 2 to 5 log
(99% to 99.999%), with an average
reduction near 3 log. For drinking water
consumption, EPA uses a distribution,
derived from the United States
Department of Agriculture's (USDA)
1994-96 Continuing Survey of Food
Intakes by Individuals, with a mean
value of 1.2 L/day. Average annual days
of exposure to drinking water in CWS,
non-transient non-community water
systems (NTNCWS), and transient non-
community water systems (TNCWS) are
estimated at 350 days, 250 days, and 10
days, respectively. (The Economic
Analysis for the LT2ESWTR (USEPA
2003a) provides details on all
parameters listed here, as well as
morbidity, mortality, and other risk
factors.)
Using an estimate of 1.2 L/day
consumption and a mean probability of
infection of 0.09 for one oocyst ingested,
the daily risk of infection (DR) is as
follows:
DR = (oocysts/L in source water) x
(percent remaining after treatment) x
(1.2 L/day) x (0.09).
The annual risk (AR) of infection for
a CWS is
AR=1-(1-DR)350
where 350 represents days of exposure
in a CWS.
Table IV-5 presents estimates of the
mean annual risk of infection by
Cryptosporidium in CWSs for selected
source water infectious oocyst
concentrations and filtration plant
removal efficiencies.
TABLE IV-5.—ANNUAL RISK OF Cryptosporidium INFECTION IN CWSs THAT FILTER, AS A FUNCTION OF SOURCE WATER
INFECTIOUS OOCYST CONCENTRATION AND TREATMENT EFFICIENCY
Source water concentration
(infectious oocysts per liter)
0.0001
0.001
0.01
0.1
1
10
2 log
3.8E-05
3.7E-04
3.7E-03
3.7E-02
0.31
0.89
3 tog
3.8E-06
3.8E-05
3.7E-04
3.7E-03
3.7E-02
0.31
4 log
3.8E-07
3.8E-06
3.8E-05
3.7E-04
3.7E-03
3.7E-02
Slog
3.8E-08
3.8E-07
3.8E-06
3.8E-05
3.7E-04
3.7E-03
Scientific notation (E"») designates 10'
For example, Table IV-5 shows that if
a filtration plant had a mean
concentration of infectious
Cryptosporidium in the source water of
0.01 oocysts/L, and the filtration plant
averaged 3 log removal, the mean
annual risk of infection by
Cryptosporidium is estimated as 3.7 x
10~4 (3.7 infections per 10,000
consumers).
ii. What degree of additional
treatment should be required for a given
source water Cryptosporidium level? In
order to develop targeted treatment
requirements for the LT2ESWTR, it was
necessary to identify a source water
Cryptosporidium level above which
additional treatment by filtered systems
would be required. Based on the type of
risk information shown in Table IV-5,
EPA and Advisory Committee
deliberations focused on mean source
water Cryptosporidium concentrations
in the range of 0.01 to 0.1 oocysts/L as
appropriate threshold values for
prescribing additional treatment.
Analytical method and sampling
constraints were a significant factor in
setting the specific Cryptosporidium
level that triggers additional treatment
by filtered systems. The number of
samples that systems can be required to
analyze for Cryptosporidium is limited.
Consequently, if the bin threshold
concentration for additional treatment
was set near 0.01 oocysts/L, systems
could exceed this level due to a very
low number of oocysts being detected.
For example, if systems took monthly 10
L samples and bin classification was
based on a maximum running annual
average, then a system would exceed a
mean concentration of 0.01 oocysts/L by
counting only 2 oocysts in 12 samples.
Given the variability associated with
Cryptosporidium analytical methods,
the Advisory Committee did not support
requiring additional treatment for
filtered systems based on so few counts.
Another concern related to analytical
method limitations was systems being
misclassified in a lower bin. For
example, if a system had a true mean
concentration at or just above 0.1
oocysts/L, the mean that the system
would determine through monitoring
might be less than 0.1 oocyst/L. Thus,
if the bin threshold for additional
treatment was set at 0.1 oocysts/L, a
number of systems with true mean
concentrations above this level would
be misclassified in the lower bin with
no additional treatment required. This
type of error, described in more detail
in the next section, is a function of the
number of samples collected and
variability in method performance.
In consideration of the available
information on Cryptosporidium risk, as
well as the performance and feasibility
of analytical methods, EPA is proposing
that the source water threshold
concentration for requiring additional
Cryptosporidium treatment by filtered
systems be established at a mean level
of 0.075 oocysts/L. This is the level
recommended by the Advisory
Committee, and it affords a high
likelihood that systems with true mean
Cryptosporidium concentrations of 0.1
oocysts/L or higher will provide
additional treatment under the rule.
Beyond identifying this first
threshold, it was also necessary to
determine Cryptosporidium
concentrations that would demarcate
higher risk bins. With respect to the
concentration range that each bin
should comprise, EPA and the Advisory
Committee dealt with two opposing
factors: bin misclassification and
equitable risk reduction.
As described in the next section, a
monthly monitoring program involving
EPA Methods 1622 or 1623 can
characterize a system's mean
Cryptosporidium concentration within a
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47671
0.5 log (factor of 3.2) margin with a high
degree of accuracy. However, the closer
a system's true mean concentration is to
a bin boundary, the greater the
likelihood that the system will be
misclassified into the wrong bin due to
limitations in sampling and analysis.
Accordingly, by establishing bins that
cover a wide concentration range, the
likelihood of system misclassification is
reduced.
However, a converse factor relates to
equitable protection from risk. Because
identical treatment requirements will
apply to all systems in the same bin,
systems at the higher concentration end
of a bin will achieve less risk reduction
relative to their source water pathogen
levels than systems at the lower
concentration end of a bin. Thus, bins
with a narrow concentration range
provide a more uniform level of public
health protection.
In balancing these factors and to
account for the wide range of possible
source water concentrations among
different systems as indicated by
Information Collection Rule and ICRSS
data, the Advisory Committee
recommended and EPA is proposing a
second bin threshold at a mean level of
1.0 oocysts/L and a third bin threshold
at a mean level of 3.0 oocysts/L.
Information Collection Rule and ICRSS
data indicate that few, if any, systems
would measure mean Cryptosporidium
concentrations greater than 3.0 oocysts/
L, so there was not a need to establish
a bin threshold above this value. Thus,
the LT2ESWTR proposal includes the
following four bins for classifying
filtered systems: Bin 1: <0.075/L; Bin 2:
>0.075 to <1.0/L; Bin 3: >1.0/L to <3.0/
L; and Bin 4: >3.0/L (oocysts/L).
With respect to additional
Cryptosporidium treatment for systems
in Bins 2-4, values were considered
ranging from 0.5 to 2.5 log and greater.
As recommended by the Advisory
Committee, EPA is proposing 1.0 log
additional treatment for conventional
plants in Bin 2. This level of treatment
will ensure that systems classified in
Bin 2 will achieve treated water
Cryptosporidium levels comparable to
systems in Bin 1, the lowest risk bin. In
contrast, if systems in Bin 2 provided
only 0.5 log additional treatment then
those systems with mean source water
concentrations in the upper part of Bin
2 would have higher levels of
Cryptosporidium in their finished water
than systems in Bin 1,
In consideration of the much greater
potential vulnerability of systems in the
highest risk bins, the Advisory
Committee recommended additional
treatment requirements of 2.0 log and
2.5 log for conventional plants in Bins
3 and 4, respectively. The Agency
concurs with these recommendations
and has incorporated them in today's
proposal.
An important aspect of the proposed
additional treatment requirements is
that they are based, in part, on the
current level of treatment provided by
filtration plants. As noted earlier, the
Advisory Committee assumed when
developing its recommendations that
conventional treatment plants in
compliance with the IESWTR achieve
an average of 3 log removal of
Cryptosporidium. EPA has determined
that available data, discussed in section
III.D, support this assumption and has
proposed a 3 log Cryptosporidium
treatment credit for conventional plants
under the LT2ESWTR. Thus, the
additional treatment requirements for
conventional plants in Bins 2, 3, and 4
translate to total requirements of 4.0,
5.0, and 5.5 log, respectively.
The Advisory Committee did not
address additional treatment
requirements for plants with treatment
trains other than conventional, but
recommended that EPA address such
plants in the proposed LT2ESWTR and
take comment. Based on treatment
studies summarized in section III.D,
EPA has concluded that plants with
slow sand or DE filtration are able to
achieve 3 log or greater removal of
Cryptosporidium when in compliance
with the IKSWTR or LTlESWTR.
Because these plants can achieve
comparable levels of performance to
conventional treatment plants, EPA is
proposing that slow sand and DE
filtration plants also apply 1 to 2.5 log
of additional treatment when classified
in Bins 2-4.
Direct filtration differs from
conventional treatment in that it does
not include sedimentation or an
equivalent clarification process prior to
filtration. As described in section III.D,
EPA has concluded that a sedimentation
process can consistently achieve 0.5 log
or greater removal of Cryptosporidium.
The Agency is proposing that direct
filtration plants in compliance with the
IESWTR or LTlESWTR receive a 2.5 log
Cryptosporidium removal credit
towards LT2ESWTR requirements.
Accordingly, proposed additional
treatment requirements for direct
filtration plants in bins 2, 3, and 4 are
1.5 log, 2.5 log, and 3 log, respectively.
Section IV.C of this notice describes
proposed criteria for determining
Cryptosporidium treatment credits for
other filtration technologies like
membranes, bag filters, and cartridge
filters. Due to the proprietary and
product specific nature of these
filtration devices, EPA is not able to
propose a generally applicable credit for
them. Rather, the criteria in section IV.C
focus on challenge testing to establish
treatment credit. Systems using these
technologies that are classified in Bins
2-4 must work with their States to
assess appropriate credit for their
existing treatment trains. This will
determine the level of additional
treatment necessary to achieve the total
treatment requirements for their
assigned bins. EPA has developed
guidance on challenge testing of bag and
cartridge filters and membranes, which
is available in draft form in the docket
(http://www.epa.gov/edocket/).
In order to give systems flexibility in
choosing strategies to meet additional
Cryptosporidium treatment
requirements, the Advisory Committee
identified a number of management and
treatment options, collectively called
the microbial toolbox. The toolbox,
which is described in section IV.C,
contains components relating to
watershed control, intake management,
pretreatment, additional filtration
processes, inactivation, and
demonstrations of enhanced
performance.
As recommended by the Advisory
Committee, EPA is proposing that
systems in Bin 2 can meet additional
Cryptosporidium treatment
requirements under the LT2ESWTR
using any component or combination of
components from the microbial toolbox.
However, systems in Bins 3 and 4 must
achieve at least 1 log of the additional
treatment requirement using
inactivation {UV, ozone, chlorine
dioxide), membranes, bag filters,
cartridge filters, or bank filtration. These
specific control measures are proposed
due to their ability to serve as
significant additional treatment barriers
for systems with high levels of
pathogens.
c. Basis for source water monitoring
requirements. The goal of monitoring
under the LT2ESWTR is to correctly
classify filtration plants into the four
LT2ESWTR risk bins. The proposed
sampling frequency, time frame, and
averaging procedure for bin
classification are intended to ensure that
systems are accurately assigned to
appropriate risk bins while limiting the
burden of monitoring costs. The basis
for the proposed monitoring
requirements for large and small
systems is presented in the following
discussion.
i. Systems serving at least 10,000
people.
Sample Number and Frequency
Systems serving at least 10,000 people
have two options for sampling under the
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Federal Register/Vol. 68, No. 154/Monday, August 11, 2Q03/Proposed Rules
LT2ESWTR: (1) They can collect 24
monthly samples over a 2 year period
and calculate their bin classification
using the highest 12 month running
annual average, or (2) They can collect
2 or more samples per month over the
2 year period and use the mean of alt
samples for bin classification.
These proposed requirements reflect
recommendations by the Advisory
Committee and are based on analyses of
misclassification rates associated with
different monitoring programs that were
considered. EPA is concerned about
systems with high concentrations of
Cryptosporidium being misclassified in
lower bins as well as systems with low
concentrations being misclassified in
higher bins. The first type of error could
lead to systems not providing an
adequate level of treatment while the
second type of error could lead to
systems incurring additional costs for
unnecessary treatment.
A primary way that EPA analyzed
misclassification rates was by
considering the likelihood that a system
with a true mean Cryptosporidium
concentration that is a factor of 3.2 (0.5
log) above or below a bin boundary
would be assigned to the wrong bin.
Probabilities were assessed for two
cases:
• False negative: a system with a
mean concentration of 0.24 oocysts/L
(i.e., factor of 3.2 above the Bin 1
boundary of 0.075 oocysts/L) is
misclassified low in Bin 1.
• False positive: a system with a
mean concentration of 0.024 oocysts/L
(i.e., factor of 3.2 below the Bin 1
boundary of 0.075 oocysts/L) is
misclassified high in Bin 2.
Table IV-6 provides false negative
and false positive rates as defined
previously for different approaches to
monitoring and bin classification that
were evaluated. Results are shown for
the following approaches:
• 48 samples with bin assignment
based on arithmetic mean (i.e., average
of all samples).
• 24 samples with bin assignment
based on highest 12 sample average,
equivalent to the maximum running
annual average (Max-RAA).
• 24 samples with bin assignment
based on arithmetic mean.
• 12 samples with bin assignment
based on the second highest sample
result.
• 8 samples with bin assignment
based on the maximum sample result.
These estimated misclassification
rates were generated with a Monte Carlo
analysis that accounted for the volume
assayed, variation in source water
Cryptosporidium occurrence, and
variable method recovery. See Economic
Analysis for the LT2ESWTR (USEPA
2003a) for details.
TABLE IV-6.—FALSE POSITIVE AND
FALSE NEGATIVE RATES FOR MONI-
TORING AND BINNING STRATEGIES
CONSIDERED FOR THE LT2ESWTR
[In percentages]
Strategy
48 sample arithmetic
24 sample Max-RAA
24 sample arithmetic
12 sample second highest
8 samoe maximum
False
posi-
tive '
1.7
5.3
2.8
47
66
False
nega-
tive2
1.4
1.7
6.2
1.1
1.0
1 False positive rates calculated for systems
with Cryptosporidium concentrations 0.5 log
below the Bin 1 boundary of 0.075 oocysts/L.
2 False negative rates calculated for sys-
tems with Cryptosporidium concentrations 0.5
log above the Bin 1 boundary of 0.075
oocysts/L.
The first two of these approaches, the
48 sample arithmetic mean and 24
sample Max-RAA, were recommended
by the Advisory Committee and are
proposed for bin classification under the
LT2ESWTR because they have low false
positive and false negative rates. As
shown in Table IV-6, these strategies
have false negative rates of 1 to 2%,
meaning there is a 98 to 99% likelihood
that a plant with an oocyst
concentration 0.5 log above the Bin 1
boundary would be correctly assigned to
Bin 2. The false positive rate is near 2%
for the 48 sample arithmetic mean and
5% for the 24 sample Max-RAA. These
rates indicate that a plant with an oocyst
concentration 0.5 log below the Bin 1
boundary would have a 95 to 98%
probability of being correctly assigned
to Bin 1. Bin misclassification rates
across a wide range of concentrations
are shown in Economic Analysis for the
LT2ESWTR (USEPA 2003a).
The 24 sample arithmetic mean had a
slightly lower false positive rate than
the 24 sample Max-RAA (2.8% vs.
5.3%) but the false negative rate of the
arithmetic mean was almost 4 times
higher. Consequently, a plant with a
mean Cryptosporidium level above the
Bin 1 boundary would be much more
likely to be misclassified in Bin 1 using
a 24 sample arithmetic mean than with
a 24 sample Max-RAA. In order to
increase the probability that systems
with mean Cryptosporidium
concentrations above 0.075 oocysts/L
will provide additional treatment, EPA
is proposing that if only 24 samples are
taken, the maximum 12 month running
annual average must be used to
determine bin assignment.
Monitoring strategies involving only
12 and 8 samples were evaluated to
determine if lower frequency
monitoring could provide satisfactory
bin classification. The results of this
analysis indicate that these lower
sample numbers are not adequate and
could unfairly bias excessive treatment
requirements. For example, results in
Table IV-6 show that if plants were
classified in bins based on the second
highest of 12 samples or the highest of
eight samples then low false negative
rates could be achieved. A system with
a mean Cryptosporidium level 0.5 log
above the Bin 1 boundary would have
a 99% chance of being appropriately
classified in a bin requiring additional
treatment under either strategy.
However, the false positive rates
associated with these low sample
numbers are very high. A system with
a mean oocyst concentration 0.5 log
below the Bin 1 boundary would have
a 47% probability of being incorrectly
classified in Bin 2 using the second
highest result among 12 samples, or a
66% likelihood of being misclassified in
Bin 2 using the maximum result among
8 samples. Due to high false positive
rates, these strategies are not proposed.
EPA also evaluated lower frequency
monitoring strategies that had lower
false positive rates, such as bin
classification based on the mean of 12
samples, the third highest result of 12
samples, and the second highest of 8
samples. Each of these strategies,
though, had an unacceptably high false
negative rate, meaning that many
systems with mean oocyst
concentrations greater than the Bin 1
boundary would be misclassified low in
Bin 1. Consequently, these strategies are
inconsistent with the public health goal
of the LT2ESWTR for systems with
mean levels above 0.075 oocysts/L to
provide additional treatment.
Increasing the number of samples
used to compute the maximum running
annual average above 24 also increased
the number of annual averages
computed, so it did not reduce the
likelihood of false positives. Raising the
number of samples used to compute an
arithmetic mean above 48 did reduce
bin misclassification rates, but the rates
were already very small (1 to 2% for
plants with levels 0.5 log above or
below bin boundaries). For sources with
Cryptosporidium concentrations very
near or at bin boundaries, increasing the
number of samples did not markedly
improve the error rates, which remained
near 50% at the bin boundaries.
In summary, EPA believes that the
proposed sampling designs perform
well for the purpose of classifying
plants in LT2ESWTR risk bins and,
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47673
thereby, achieving the public health
protection intended for the rule. More
costly designs, involving more frequent
sampling and analysis, provide only
marginally improved performance. Less
frequent sampling, though lower in cost,
creates unacceptably high
misclassification rates and would not
provide for the targeted risk reduction
goals of the rule.
No Adjustments for Method Recovery or
Percent of Oocysts That Are Infectious
Two considerations in using
Cryptosporidium monitoring data to
project risk are (1) Fewer than 100% of
oocysts in a sample are recovered and
counted by the analyst and (2) not all
the oocysts measured with Methods
1622/23 are viable and capable of
causing infection. These two factors are
offsetting in sign, in that oocyst counts
not adjusted for recovery tend to
underestimate the true concentration,
while the total oocyst count may
overestimate the infectious
concentration that presents a health
risk. Based on information described in
this section, EPA is proposing that
Cryptosporidium monitoring results be
used directly to assign systems to
LT2ESWTR'risk bins and not be
adjusted for either factor.
As described in section III.C, ICRSS
matrix spike data indicate that average
recovery of Cryptosporidium oocysts
with Methods 1622/23 in a national
monitoring program will be about 40%.
There is no similar direct measure of the
fraction of environmental oocysts that
are infectious, but information related to
this value can be derived from two
sources: (1) A study where samples
were analyzed with both Method 1623
and a cell culture-polymerase chain
reaction (CC-PGR) test for oocyst
infectivity, and (2) the structure of
oocysts counted with Methods 1622 and
1623.
LeChevallier et al. (2003) conducted a
study in which six natural waters were
frequently tested for Cryptosporidium
using both Method 1623 and a CC-PCR
method to test for infectivity.
Cryptosporidium oocysts were detected
in 60 of 593 samples (10.1%) by Method
1623 and infectious oocysts were
detected in 22 of 560 samples (3.9%) by
the CC-PCR procedure. Recovery
efficiencies for the two methods were
similar. According to the authors, these
results suggest that approximately 37%
(22/60) of the Cryptosporidium oocysts
detected by Method 1623 were viable
and infectious.
In regard to oocyst structure,
Cryptosporidium oocysts counted with
Methods 1622/23 are characterized in
one of three ways: (l) Internal
structures, (2) amorphous structures, or
(3) empty. Oocysts with internal
structures are considered to have the
highest likelihood of being infectious,
while empty oocysts are believed to be
non-viable (LeChevallier et al, 1997).
During the ICRSS, 37% of the oocysts
counted were characterized as having
internal structures, 47% had amorphous
structures, and 16% were empty. If it is
assumed that empty oocysts could not
be infectious, the mid-point value
within the percentage range of counted
oocysts that could have been infectious
is 42%.
After considering this type of
information, the Advisory Committee
recommended that monitoring results
not be adjusted upward for percent
recovery, nor adjusted downward to
account for the fraction of oocysts that
are not infectious. While it is not
possible to establish a precise value for
either factor in individual samples, the
data suggest that they may be of similar
magnitude. EPA concurs with this
recommendation and is proposing that
systems be classified in bins under the
LT2ESWTR using the total
Cryptosporidium oocyst count,
uncorrected for recovery, as measured
using EPA Method 1622/23. The
proposed LT2ESWTR risk bins are
constructed to reflect this approach.
Data Collection To Support Use of a
Microbial Indicator by Small Systems
As described in the next section,
small systems will monitor for an
indicator, currently proposed to be E.
coli, to determine if they are required to
sample for Cryptosporidium. The
proposed E. coli levels that will trigger
Cryptosporidium monitoring are based
on Information Collection Rule and
ICRSS data. However, to provide for a
more extensive evaluation of
Cryptosporidium indicator criteria, EPA
is proposing that large systems measure
E. coli and turbidity in their source
water when they sample for
Cryptosporidium. This was-
recommended by the Advisory
Committee and will allow for possible
development of alternative indicator
levels or parameters (e.g., turbidity in
combination with E. coli) to serve as
triggers for small system
Cryptosporidium monitoring.
Time Frame for Monitoring
In recommending a time frame for
LT2ESWTR monitoring, the Agency
considered the trade-off between
monitoring over a long period to better
capture year-to-year fluctuations, and
the desire to prescribe additional
treatment quickly to systems identified
as having high source water pathogen
levels. Reflecting Advisory Committee
recommendations, EPA is proposing
that large systems evaluate their source
water Cryptosporidium levels using 2
years of monitoring. This will account
for some degree of yearly variability,
without significantly delaying
additional public health protection
where needed.
ii. Systems serving fewer than 10,000
people.
Indicator Monitoring
In recognition of the relatively high
cost of analyzing samples for
Cryptosporidium, EPA and the Advisory
Committee explored the use of indicator
criteria to identify drinking water
sources that may have high levels of
Cryptosporidium occurrence. The goal
was to find one or more parameters that
could be analyzed at low cost and
identify those systems likely to exceed
the Bin 1 boundary of 0.075 oocysts/L.
Data from the Information Collection
Rule and ICRSS were evaluated for
possible indicator parameters, including
fecal coliforms, total coliforms, E. coli,
viruses (Information Collection Rule
only), and turbidity. Based on available
data, E. coli was found to provide the
best performance as a Cryptosporidium
indicator, and the inclusion of other
parameters like turbidity was not found
to improve accuracy.
The next part of this section presents
data that support E. coli mean
concentrations of 10/100 mL and 50/100
mL as proposed screening levels that
will trigger Cryptosporidium monitoring
in reservoir/lake and flowing stream
systems, respectively. It describes how
E. coli and Cryptosporidium data from
the Information Collection Rule and
ICRSS were analyzed and shows the
performance of different concentrations
of E. coli as an indicator for systems that
will exceed the Bin 1 boundary of 0.075
oocysts/L.
Information Collection Rule data were
evaluated as maximum running annual
averages (Information Collection Rule
samples were collected once per month
for 18 months) while ICRSS data were
evaluated using an annual mean (ICRSS
samples were collected twice per month
for 12 months). In addition, as
indicators were being evaluated it
became apparent that it was necessary
to analyze plants separately based on
source water type, due to a significantly
different relationship between E. coli
and Cryptosporidium in reservoir/lake
systems compared to flowing stream
systems.
Analyzing the performance of an E.
coli level as a screen to trigger
Cryptosporidium monitoring under the
proposed LT2ESWTR involved
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evaluating each water treatment plant in
the data set relative to two factors: (1)
Did the plant E. coli level exceed the
trigger value being assessed? and (2) Did
the plant mean Cryptosporidium
concentration exceed 0.075 oocysts/L?
Accordingly, plants were sorted into
four categories, based on
Cryptosporidium and E. coli
concentrations:
• Plants with Cryptosporidium <
0.075 oocysts/L that did not exceed the
E. coli trigger level (Figure IV-1, box A)
• Plants with Cryptosporidium <
0,075 oocysts/L that exceeded the E. coli
trigger level (Figure IV. 1, box B)
• Plants with Cryptosporidium >
0.075 oocysts/L that did not exceed the
E. coli trigger level (Figure IV.1. box C)
• Plants with Cryptosporidium >
0.075 oocysts/L that exceeded the E. coli
trigger level (Figure IV.l, box D)
Summary data with E. coli trigger
concentrations ranging from 5 to 100 per
100 mL are presented for Information
Collection Rule and ICRSS data in
Figures W-2 and IV-3.
The performance of each E. coli level
as a trigger for Cryptosporidium
monitoring was evaluated based on false
negative and false positive rates. False
negatives occur when plants do not
exceed the E. coli trigger value, but
exceed a Cryptosporidium level of 0.075
oocysts/L. False positives occur when
plants exceed the E. coli trigger value
but do not exceed a Cryptosporidium
level of 0.075 oocysts/L. The false
negative rate is critical because it
characterizes the ability of the indicator
to identify those plants with high
Cryptosporidium levels. In general, low
false negative rates can be achieved by
lowering the E. coli trigger
concentration. However, when the E,
coli trigger concentration is decreased,
more plants with low Cryptosporidium
levels in their source water exceed it. As
a result, more plants incur false
positives. Consequently, identifying an
appropriate E. coli concentration to
trigger Cryptosporidium monitoring
involves balancing false negatives and
false positives to minimize both.
Results of the indicator analysis for
plants with flowing stream sources are
shown in Figure IV-2. An E. coli trigger
concentration of 50/100 mL produced
zero false negatives for both data sets.
This means that in these data sets, all
plants that exceeded mean
Cryptosporidium concentrations of
0.075 oocysts/L also exceeded the E. coli
trigger concentration and would,
therefore, be required to monitor.
However, this trigger concentration had
a significant false positive rate (i.e., it
was not highly specific in targeting only
those plants with high Cryptosporidium
levels). False positive rates were 57%
(24/42) and 53% (9/17) with
Information Collection Rule and ICRSS
data, respectively. At a higher E. coli
trigger concentration, such as 100/100
mL, the false negative rate increased to
12.5% (3/24) with Information
Collection Rule data and 50% (2/4) with
ICRSS data, while the false positive rate
decreased to 43% (18/42) and 35% (6/
17), respectively. Consequently, EPA is
proposing a mean E. coli concentration
of 50/100 mL as a trigger for
Cryptosporidium monitoring by small
systems with flowing stream sources.
Results of the indicator analysis for
plants with reservoir/lake sources are
shown in. Figure IV-3. An E. coli trigger
of 10/100 mL resulted in a false negative
rate of 20% (2/10) with Information
Collection Rule data and 67% (2/3) with
ICRSS data (misclassified 2 out of 3
plants over 0.075 oocysts/L). Going to a
lower concentration E. coli trigger, such
as 5 per 100 mL, decreased the false
negative rate in both the Information
Collection Rule and ICRSS data sets by
one plant, but increased the false
positive rate from 20% to 43% (13/30)
in the ICRSS data and from 24% to 39%
(44/114) in the Information Collection
Rule data. Based on these results, EPA
is proposing that a mean E. coli
concentration of 10/100 mL trigger
small systems using lake/reservoir
sources into monitoring for
Cryptosporidium. While the false
negative rate associated with this trigger
value in the ICRSS data set is high, the
ICRSS data set contains only 3
reservoir/lake plants that exceeded a
Cryptosporidium level of 0.075 oocysts/
L.
Due to limitations in the available
data, the Advisory Committee did not
recommend that large systems use the E.
coli indicator screen, as
Cryptosporidium monitoring is less of
an economic burden for large systems-
Rather, the Advisory Committee
recommended that large systems sample
for E, coli and turbidity when they
monitor for Cryptosporidium under the
LT2ESWTR. These data will then be
used to verify or, if necessary, further
refine the proposed indicator trigger
values for small systems. EPA concurs
with these recommendations and they
are reflected in today's proposal.
The proposed monitoring schedule
under the LT2ESWTR is set up to allow
EPA and stakeholders to evaluate large
system monitoring data for indicator
relationships prior to the start of small
system E. coli monitoring. After one
year of large system monitoring is
completed, EPA will begin analyzing
monitoring data to assess whether
alternative indicator strategies would be
appropriate. Depending on the findings
of this analysis, EPA may issue
guidance to States on approving
alternative indicator trigger strategies for
small systems. Therefore, the proposed
rule is written with the allowance for
States to approve alternative indicator
strategies.
BILLING CODE 6560-50-P
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Federal Register/Vol. 68, No. 154/Monday, August 11, 2003/Proposed Rules
47675
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47676
Federal Register/Vol. 68, No, 154/Monday, August 11, 2003 / Proposed Rules
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-------
Federal Register/Vol. 68, No. 154/Monday, August 11, 2003/Proposed Rules
47677
BILLING CODE 6560-50-C
Cryptosporidium Monitoring
Small systems that exceed the E. coli
trigger must conduct Cryptosporidium
monitoring, beginning 6 months after
completion of£". coli monitoring. As
recommended by the Advisory
Committee, EPA is proposing that small
systems collect 24 Cryptosporidium
samples over a period of one year. This
number of samples is the same as
required for large systems, but the
monitoring burden is targeted only on
those plants that E. coli monitoring
indicates to have elevated levels of fecal
matter in the source water. By
completing Cryptosporidium monitoring
in one year, small systems will conduct
a total of 2 years of monitoring to
determine LT2ESWTR bin classification
(including the one year of E. coli
monitoring). This time frame is
equivalent to the requirement for large
systems, which monitor for
Cryptosporidium, E. coli, and turbidity
for 2 years.
The Stage 2 M-DBP Agreement in
Principle recommended that EPA
explore the feasibility of alternative,
lower frequency, Cryptosporidium
monitoring criteria for providing a
conservative mean estimate in small
systems. As described earlier, EPA has
evaluated smaller sample sizes, such as
systems taking 12 or 8 samples instead
of 24 (see Table IV-6). However, EPA
has concluded that these smaller sample
sizes result in unacceptably high
misclassification rates. For example, bin
classification based on the second
highest of 12 samples produces an
estimated false positive rate of 47% for
systems with a mean Cryptosporidium
concentration 0.5 log below the Bin 1
boundary of 0.075/L. In comparison, bin
classification based on the mean of 24
samples achieves a false positive rate of
2.8% for systems at this
Cryptosporidium concentration.
Consequently, EPA is proposing no
alternatives to the requirement that
small systems take at least 24 samples.
Small system bin classification will be
determined by the arithmetic mean of
the 24 samples collected over one year.
Because the bin structure in the
LT2ESWTR is based on annual mean
Cryptosporidium levels, it is necessary
that bin classification involve averaging
samples over at least one year.
Consequently, small systems will
determine their bin classification by
averaging results from all
Cryptosporidium samples collected
during their one year of monitoring.
iii. Future monitoring and
reassessment. EPA is proposing that
beginning 6 years after the initial bin
classification, large and smail systems
conduct another round of monitoring to
determine if source water conditions
have changed to a degree that may
warrant a revised bin classification. The
Advisory Committee recommended that
EPA convene a stakeholder process
within 4 years after the initial bin
classification to develop
recommendations on how best to
proceed with implementing this second
round of monitoring. Unless EPA
modifies the LT2ESWTR to allow for an
improved analytical method or a revised
bin structure based on new risk
information, the second round of
monitoring will be conducted under the
same requirements that apply to the
initial round of monitoring.
In addition, EPA is proposing to use
the required assessment of the water
source during sanitary surveys as an
ongoing measure of whether significant
changes in watersheds have occurred
that may lead to increased
contamination. Where the potential for
increased contamination is identified,
States must determine what follow-up
actions by the system are necessary,
including the possibility of the system
providing additional treatment from the
microbial toolbox.
d. Basis for accepting previously
collected data. Members of the Advisory
Committee had multiple objectives in
recommending that EPA allow the use
of previously collected (grandfathered)
Cryptosporidium data. These include (1)
giving credit for data collected by
proactive utilities, (2) facilitating early
determination of LT2ESWTR
compliance needs and, thereby,
allowing for early planning of
appropriate treatment selection, (3)
increasing laboratory capacity to meet
demand for Cryptosporidium analysis
under the LT2ESWTR, and (4) allowing
utilities to improve their data set for bin
determination by considering more than
2 years of data (i.e., include data
collected prior to effective date of
LT2ESWTR). The latter objective
incorporates the assumption that
occurrence can vary from year to year,
so that if more years of data are used in
the bin determination, the source water
concentration estimate will be a more
accurate representation of the overall
mean.
A significant issue with accepting
previously collected data for making bin
determinations is ensuring that the data
are of equivalent quality to data that
will be collected following LT2ESWTR
promulgation. As noted previously, EPA
is establishing requirements so that data
collected under the LT2ESWTR will be
similar in quality to data that were
generated under the ICRSS. These
requirements include the use of
approved analytical methods and
compliance with method quality control
(QC) criteria, use of approved
laboratories, minimum sample volume,
and a sampling schedule with minimum
frequency. For example, under the
ICRSS, laboratories analyzed 10 L
samples and (considered collectively)
achieved a mean Cryptosporidium
recovery of approximately 43% in
spiked source water with a relative
standard deviation (RSD) of 50%. EPA
anticipates that laboratories conducting
Cryptosporidium analysis for the
LT2ESWTR will collectively achieve
similar analytical method performance.
Consequently, EPA expects previously
collected data sets used under the
LT2ESWTR to meet these standards and
has established criteria for accepting
previously collected data accordingly
(see section IV.A.I.d).
Systems are requested, but not
required, to notify EPA prior to
promulgation of the LT2ESWTR of their
intent to submit previously collected
data. This will help EPA allocate the
resources that will be needed to
evaluate these data in order to make a
decision on adequacy for bin
determination. Systems that have at
least 2 years of previously collected data
to grandfather when the LT2ESWTR is
promulgated and do not intend to
conduct new monitoring under the rule
are required to submit the previously
collected data to EPA within 2 months
following promulgation. This will
enable EPA to evaluate the data and
report back to the utility in sufficient
time to allow, if needed, the utility to
contract with a laboratory to conduct
monitoring under the LT2ESWTR.
Systems that have fewer than 2 years
of previously collected data to
grandfather when the LT2ESWTR is
promulgated, or that intend to
grandfather 2 or more years of
previously collected data and also
conduct new monitoring under the rule,
are required to submit the previously
collected data to EPA within 8 months
following promulgation. This will allow
these utilities to continue to collect
previously collected data in the 6 month
period between promulgation and the
date when monitoring under the
LT2ESWTR must begin, plus a 2 month
period for systems to compile the data
and supporting documentation. Utilities
may submit the data earlier than 8
months after promulgation if they
acquire 2 years of previously collected
data before this date.
Submitted grandfathered data sets
must include all routine source water
monitoring results for samples collected
during the time period covered by the
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47678
Federal Register/Vol. 68, No. 154/Monday, August 11, 2003/Proposed Rules
grandfathered data set (i.e., the time
period between collection of the first
and last samples in the data set).
However, systems are not required
under the LT2ESWTR to submit
previously collected data for samples
outside of this time period.
3. Request for Comment
EPA requests comments on all aspects
of the monitoring and treatment
requirements proposed in this section.
In addition, EPA requests comment on
the following issues:
Requirements for Systems That Use
Surface Water for Only Part of the Year
Bin classification for the LT2ESWTR
is based on the mean annual
sourcewater Cryptosporidium level.
Consequently, today's proposal requires
E. coli and Cryptosporidium monitoring
to be conducted over the full year.
However, EPA recognizes that some
systems use surface water for only part
of the year. This occurs with systems
that use surface water for part of the
year (e.g., during the summer) to
supplement ground water sources and
with systems like campgrounds that are
in operation for only part of the year.
Year round monitoring for these systems
may present both logistic and economic
difficulties. EPA is requesting comment
on how to apply LT2ESWTR monitoring
requirements to surface water systems
that operate or use surface water for
only part of the year. Possible
approaches that may be considered for
comment include the following:
Small public water systems that
operate or use surface water for only
part of the year could be required to
collect E. coli samples at least bi-weekly
during the period when they use surface
water. If the mean E. coli concentration
did not exceed the trigger level (e.g., 10/
100 mL for reservoirs/lakes or 50/100mL
for flowing streams), systems could
apply to the State to waive any
additional E. coli monitoring. The State
could grant the waiver, require
additional E. coli monitoring, or require
monitoring of an alternate indicator. If
the mean E. coli concentration exceeded
the trigger level, the State could require
the system to provide additional
' treatment for Cryptosporidium
consistent with Bin 4 requirements, or
require monitoring of Cryptosporidium
or an indicator, with the results
potentially leading to additional
Cryptosporidium treatment
requirements.
Large public water systems that
operate or use surface water for only
part of the year could be required to
collect Cryptosporidium samples (along
with E. coli and turbidity) either twice-
per-month during the period when they
use surface water or 12 samples per
year, whichever is smaller. Samples
would be collected during the two years
of the required monitoring period, and
bin classification would be based on the
highest average of the two years.
EPA requests comment on these and
other approaches for both small and
large systems.
Previously Collected Monitoring Data
That Do Not Meet QC Requirements
EPA is proposing requirements for
acceptance of previously collected
monitoring data that are equivalent to
requirements for data generated under
the LT2ESWTR. The Agency is aware
that systems will have previously
collected Cryptosporidium data that do
not meet ail sampling and analysis
requirements (e.g., quality control,
sample frequency, sample volume)
proposed for data collected under the
LT2ESWTR. However, the Agency has
been unable to develop an approach for
allowing systems to use such data for
LT2ESWTR bin classification. This is
due to uncertainty regarding the impact
of deviations from proposed sampling
and analysis requirements on data
quality and reliability. For example,
Methods 1622 and 1623 have been
validated within the limits of the QC
criteria specified in these methods.
While very minor deviations from
required QA/QC criteria may have only
a minor impact on data quality, the
Agency has not identified a basis for
establishing alternative standards for
data acceptability.
EPA requests comment on whether or
under what conditions previously
collected data that do not meet the
proposed criteria for LT2ESWTR
monitoring data should be accepted for
use in bin determination. Specifically,
EPA requests comment on the sampling
frequency requirement for previously
collected data, and whether EPA should
allow samples collected at lower or
varying frequencies to be used as long
as the data are representative of seasonal
variation and include the required
number of samples. If so, how should
EPA determine whether such a data set
is unbiased and representative of
seasonal variation? How should data
collected at varying frequency be
averaged?
Monitoring for Systems That Recycle
Filter Backwash
Plants that recycle filter backwash
water may, in effect, increase the
concentration of Cryptosporidium in the
water that enters the filtration treatment
train. Under the LT2ESWTR proposal,
microbial sampling may be conducted
on source water prior to the addition of
filter backwash water. EPA requests
comment on how the effect of recycling
filter backwash should be considered in
LT2ESWTR monitoring.
Bin Assignment for Systems That Fail
To Complete Required Monitoring
Today's proposal classifies systems
that fail to complete required
monitoring in Bin 4, the highest
treatment bin. EPA requests comment
on alternative approaches for systems
that fail to complete required
monitoring, such as classifying the
system in a bin based on data the system
has collected, or classifying the system
in a bin one level higher than the bin
indicated by the data the system has
collected. The shortcoming to these
alternative approaches is that bin
classification becomes more uncertain,
and the likelihood of bin
misclassification increases, as systems
collect fewer than the required 24
Cryptosporidium samples.
Consequently, the proposed approach is
for systems to collect all required
samples.
Note that under today's proposal,
systems may provide 5.5 log of
treatment for Cryptosporidium (i.e.,
comply with Bin 4 requirements) as an
alternative to monitoring. Where
systems notify the State that they will
provide treatment instead of monitoring,
they will not incur monitoring
violations.
Monitoring Requirements for New
Plants and Sources
The proposed LT2ESWTR would
establish calendar dates when the initial
and second round of source water
monitoring must be conducted to
determine bin classification. EPA
recognizes that new plants will begin
operation, and that existing plants will
access new sources, after these dates.
EPA believes that new plants and plants
switching sources should conduct
monitoring equivalent to that required
of existing plants to determine the
required level of Cryptosporidium
treatment. The monitoring could be
conducted before a new plant or source
is brought on-line, or initiated within
some time period afterward. EPA
requests comment on monitoring and
treatment requirements for new plants
and sources.
Determination of LT2ESWTR Bin
Classification
In today's proposal, EPA expects that
systems will be assigned to LT2ESWTR
risk bins based on their reported
Cryptosporidium monitoring results and
the calculations proposed for bin
-------
• assignment described in this section.
I EPA requests comment on whether bin
I classifications should formally be made
I or reviewed by States.
I Source Water Type Classification for
I Systems That Use Multiple Sources
• ' In today's proposal, the E, coli
| concentrations that trigger small system
Cryptosporidium monitoring are
different for systems using lake/
reservoir and flowing stream sources.
However, EPA recognizes that some
systems use multiple sources,
potentially including both lake/reservoir
and flowing stream sources, and that the
use of different sources may vary during
the year. Further, some systems use
sources that are ground water under the
direct influence (GWUD1) of surface
water. EPA requests comment on how to
apply the E. coli criteria for triggering
Cryptosporidium monitoring to systems
using multiple sources and GWUDI
sources.
B. Unfiltered System Treatment
Technique Requirements for
Cryptosporidium
1. What Is EPA Proposing Today?
a. Overview. EPA is proposing
treatment technique requirements for
Cryptosporidium in unfiltered systems.
Today's proposal requires all unfiltered
systems using surface water or ground
water under the direct influence of
surface water to achieve at least 2 log
(99%) inactivation of Cryptosporidium
prior to the distribution of finished
water. Further, unfiltered systems must
monitor for Cryptosporidium in their
source water, and where monitoring
demonstrates a mean level above 0.01
oocysts/L, systems must provide at least
3 log Cryptosporidium inactivation.
Disinfectants that can be used to meet
this treatment requirement include
ozone, ultraviolet (UV) light, and
chlorine dioxide.
All current requirements for
unfiltered systems under 40 CFR 141.71
and 141.72(a} remain in effect,
including requirements to inactivate at
least 3 log of Giardia lamblia and 4 log
of viruses. In addition, unfiltered
systems must meet their overall
disinfection requirements using a
minimum of two disinfectants. These
proposed requirements reflect
recommendations of the Stage 2 M-DBP
Federal Advisory Committee. Details of
the proposed requirements are
described in the following sections.
b. Monitoring requirements.
Requirements for Cryptosporidium
monitoring by unfiltered systems are
similar to requirements for filtered
systems of the same size, as given in
Federal Register/Vol. 68, No. 154/Monday, August 11, 2003/-Proposed Rules
47679
section IV.A.l. Unfiltered systems
serving at least 10,000 people must
sample their source water for
Cryptosporidium at least monthly for
two years, beginning no later than 6
months after promulgation of this rule.
Samples may be collected more
frequently (e.g., semi-monthly, weekly)
as long as a consistent frequency is
maintained throughout the monitoring
period.
Unfiltered systems serving fewer than
10,000 people must conduct source
water sampling for Cryptosporidium at
least twice-per-month for one year,
beginning no later than 4 years
following promulgation of this rule (i.e.,
on the same schedule as small filtered
systems). However, unlike small filtered
systems, small unfiltered systems
cannot monitor for an indicator (e.g., E.
coli] to determine if they are required to
monitor for Cryptosporidium. EPA has
not identified indicator criteria that can
effectively screen for plants with
Cryptosporidium concentrations below
0.01 oocysts/L. Consequently, al! small
unfiltered systems must conduct
Cryptosporidium monitoring.
As described in section IV.K and IV.L,
Cryptosporidium analyses must be
performed on at least 10 L per sample
with EPA Methods 1622 or 1623, and
must be conducted by laboratories
approved for these methods by EPA.
Analysis of larger sample volumes is
allowed, provided the laboratory has
demonstrated comparable method
performance to that achieved on a 10 L
sample. Section IV J describes
requirements for reporting sample
analysis results. All Cryptosporidium
samples must be collected in
accordance with a schedule that is
developed by the system and submitted
to EPA or the State at least 3 months
prior to initiation of sampling. Refer to
section IV.A.l for requirements
pertaining to any failure to report a
valid sample analysis result for a
scheduled sampling date and
procedures for collecting a replacement
sample.
Unfiltered systems are required to
participate in future Cryptosporidium
monitoring on the same schedule as
filtered systems of the same size. Future
monitoring requirements for filtered
systems are described in section IV.A.l.
Unfiltered systems are not required to
conduct source water Cryptosporidium
monitoring under the LT2ESWTR if the
system currently provides or will
provide a total of at least 3 log
Cryptosporidium inactivation,
equivalent to meeting the treatment
requirements for unfiltered systems
with a mean Cryptosporidium
concentration of greater than 0.01
oocysts/L. Systems must notify the State
not later than the date the system is
otherwise required to submit a sampling
schedule for monitoring. Systems must
install and operate technologies to
provide a total of at least 3 log
Cryptosporidium inactivation by the
applicable date in Table IV—24.
c. Treatment requirements. All
unfiltered systems must provide
treatment for Cryptosporidium, and the
degree of required treatment depends on
the level of Cryptosporidium in the
source water as determined through
monitoring. Unfiltered systems must
calculate their average source water
Cryptosporidium concentration using
the arithmetic mean of all samples
collected during the required two year
monitoring period (or one year
monitoring period for small systems).
For unfiltered systems with mean
source water Cryptosporidium levels of
less than or equal to 0.01 oocysts/L, 2
log Cryptosporidium inactivation is
required. Where the mean source water
level is greater than 0.01 oocysts/L, 3 log
inactivation is required.
In addition, unfiltered systems are
required to use at least two different
disinfectants to meet their overall
inactivation requirements for viruses (4
log), Giardia lamblia (3 log), and
Cryptosporidium (2 or 3 log). Further,
each of the two disinfectants must
achieve by itself the total inactivation
required for one of these three pathogen
types. For example, a system could use
UV light to achieve 2 log inactivation of
Cryptosporidium and Giardia lamblia,
and use chlorine to inactivate 1 log
Giardia lamblia and 4 log viruses. In
this case, chlorine would achieve the
total inactivation required for viruses
while UV light would achieve the total
inactivation required for
Cryptosporidium, and the two
disinfectants together would meet the
overall treatment requirements for
viruses, Giardia lamblia, and
Cryptosporidium. In all cases unfiltered
systems must continue to meet
disinfectant residual requirements for
the distribution system.
EPA has developed criteria, described
in sections IV.C.14-15, for systems to
determine Cryptosporidium inactivation
credits for chlorine dioxide, ozone, and
UV light. Unfiltered systems are allowed
to use any of these disinfectants to meet
the 2 (or 3) log Cryptosporidium
inactivation requirement. The following
paragraphs describe standards for
demonstrating compliance with the
proposed Cryptosporidium treatment
technique requirement. For systems
using ozone and chlorine dioxide, these
standards are similar to current
standards for compliance with Giardia
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Federal Register/Vol. 68, No. 154/Monday, August 11. 2003/Proposed Rules
lamblia and virus treatment
requirements, as established by the
SWTR in 40 CFR 141.72 and 141.74,
However, for systems using UV light,
modified compliance standards are
proposed, due to the different way in
which UV disinfection systems will be
monitored.
Each day a system using ozone or
chlorine dioxide serves water to the
public, the system must calculate the CT
value(s) from the system's treatment
parameters, using the procedures
specified in 40 CFR 14l.74(b)(3). The
system must determine whether this
value(s) is sufficient to achieve the
required inactivation of
Cryptosporidmm based on the CT
criteria specified in section IV.C.14. The
disinfection treatment must ensure at
least 99 percent (or 99.9 percent if
required) inactivation of
Cryptosporidium every day the system
serves water to the public, except any
one day each month. Systems are
required to report daily CT values on a
monthly basis, as described in section
1V.J.
Each day a system using UV light
serves water to the public, the system
must monitor for the parameters,
including flow rate and UV intensity,
that demonstrate whether the system's
UV reactors are operating within the
range of conditions that have been
validated to achieve the required UV
dose, as specified in section IV.C.15.
Systems must monitor each UV reactor
while in use and must record periods
when any reactor operates outside of
validated conditions. The disinfection
treatment must ensure at least 99
percent (or 99.9 percent if required]
inactivation of Cryptosporidium in at
least 95 percent of the water delivered
to the public every month. Systems are
required to report periods when UV
reactors operate outside of validated
conditions on a monthly basis, as
described in section IV.].
Unfiltered systems currently must
comply with requirements for DBFs as
a condition of avoiding filtration under
40 CFR 141.71(b)(6). As described
earlier, EPA is developing a Stage 2
DBPR, which will further limit
allowable levels of certain DBFs,
specifically tribal omethanes and
haloacetic acids. EPA intends to
incorporate new standards for DBFs
established under the Stage 2 DBPR into
the criteria for filtration avoidance.
2. How Was This Proposal Developed?
a. Basis for Cryptosporidium
treatment requirements. The intent of
the proposed treatment requirements for
unfiltered systems is to achieve public
health protection against
Cryptosporidium equivalent to filtration
systems. As described in section III.C,
an assessment of survey data indicates
that under current treatment
requirements, finished water
Cryptosporidium levels are higher in
unfiltered systems than in filtered
systems.
Information Collection Rule data
show an average plant-mean
Cryptosporidium level of 0.59 oocysts/L
in the source water of filtered plants and
0.014 oocysts/L in unfiltered systems.
Median plant-mean concentrations were
0.052 and 0.0079 oocysts/L in filtered
and unfiltered system sources,
respectively. Thus, these results suggest
that typical Cryptosporidium occurrence
in filtered system sources is
approximately 10 times higher than in
unfiltered system sources.
In translating these data to assess
finished water risk, EPA and the
Advisory Committee estimated that
conventional plants in compliance with
the IESWTR achieve an average
Cryptosporidium removal of 3 log (see
discussion in section III.D). Hence, if the
median source water Cryptosporidium
level at conventional plants is
approximately 10 times higher than at
unfiltered systems, and it is estimated
that conventional plants achieve an
average reduction of 3 log (99.9%), then
the median finished water
Cryptosporidium concentration at
conventional plants is lower by a factor
of 100 than at unfiltered systems.
Therefore, to ensure equivalent public
health protection, unfiltered systems
should reduce Cryptosporidium levels
by 2 log.
Due to the development of criteria for
Cryptosporidium inactivation with
ozone, chlorine dioxide, and UV light,
EPA has determined that it is feasible
for unfiltered systems to comply with a
Cryptosporidium treatment technique
requirement. Consequently, EPA is
proposing that all unfiltered systems
provide at least 2 log inactivation of
Cryptosporidium.
The proposed treatment requirements
for unfiltered systems with higher
source water Cryptosporidium levels are
consistent with proposed treatment
requirements for filtered systems. As
discussed previously, EPA is proposing
that filtered plants with mean source
water Cryptosporidium levels between
0.075 and 1.0 oocysts/L, as measured by
Methods 1622 and 1623, provide at least
a 4 log reduction (with greater treatment
required for higher source water
pathogen levels). These requirements
will achieve average treated water
Cryptosporidium concentrations below
1 oocyst/10,000 L in filtered systems.
An unfiltered system with a mean
source water Cryptosporidium
concentration above 0.01 oocyst/L
would need to provide more than 2 log
inactivation in order to achieve an
equivalent finished water oocyst level.
Therefore, EPA is proposing that
unfiltered systems provide at least 3 log
inactivation where mean concentrations
exceed 0.01 oocysts/L.
For unfiltered systems using UV
disinfection to meet these proposed
Cryptosporidium treatment
requirements, EPA is proposing that
compliance be based on a 95th
percentile standard (i.e., at least 95
percent of the water must be treated to
the required UV dose). This standard is
intended to be comparable with the
"every day except any one day per
month" compliance standard
established by the SWTR for chemical
disinfection (see 40 CFR 141.72(a)(l)).
Because UV disinfection systems will
typically consist of multiple parallel
reactors that will be monitored
continuously, the Agency has
determined that it is more appropriate
to base a compliance determination on
the percentage of water disinfected to
the required level, rather than a single
daily measurement. The UV
Disinfection Guidance Manual (USEPA
2003d) will provide advice on meeting
this proposed standard. A draft of this
guidance is available in the docket for
today's proposal (http://www.epa.gov/
edocketf).
b. Basis for requiring the use of two
disinfectants. EPA is proposing that
unfiltered systems use at least two
different disinfectants to meet the 2 (or
3}, 3, and 4 log inactivation
requirements for Cryptosporidium,
Giardia lamblia, and viruses,
respectively. The purpose of this
requirement is to provide for multiple
barriers of protection against pathogens.
One benefit of this approach is that if
one barrier were to fail then there would
still be one remaining barrier to provide
protection against some of the
pathogens that might be present. For
example, if a plant used UV to
inactivate Cryptosporidium and Giardia
lamblia, along with chlorine to
inactivate viruses, and the UV system
were to malfunction, the chlorine would
still meet the treatment requirement for
viruses and would provide some degree
of protection against Giardia lamblia.
Another benefit of multiple barriers is
that they will typically provide more
effective protection against a broad
spectrum of pathogens than a single
disinfectant. Because the efficacy of
disinfectants against different pathogens
varies widely, using multiple
disinfectants will generally provide
more efficient inactivation of a wide
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range of pathogens than a single
disinfectant.
EPA is aware, though, that this
requirement would not result in a
redundant barrier for each type of
pathogen. In the example of a plant
using chlorine and UV, the chlorine
would provide essentially no protection
against Cryptosporidium and might
achieve only a small amount of Giardia
lamblia inactivation if it was designed
primarily to inactivate viruses.
However, since the watersheds of
unfiltered systems are required to be
protected (40 CFR 141.71), the
probability is tow that high levels of
Cryptosporidium or Giardia lamblia
would occur during the time frame
necessary to address a short period of
treatment failure.
Note the request for comment on this
topic at the end of this section.
c. Basis for source water monitoring
requirements. Monitoring by unfiltered
systems is necessary to identify those
with mean source water
Cryptosporidium levels above 0.01
oocysts/L. In order to allow for
simultaneous compliance with other
microbial and disinfection byproduct
regulatory requirements, EPA is
proposing that unfiltered systems
monitor for Cryptosporidium on the
same schedule as filtered systems of the
same size. Because EPA was not able to
identify indicator criteria, such as E.
coli, that can discriminate among
systems above and below a mean
Cryptosporidium concentration of 0.01
oocysts/L, EPA is proposing that all
unfiltered systems monitor for
Cryptosporidium.
Consistent with requirements for
filtered systems, unfiltered systems are
required to analyze at least 24 samples
of at least 10 L over the two year
monitoring period (one year for small
systems). However, if an unfiltered
system collected and analyzed only 24
samples of 10 L then a total count of 3
oocysts among all samples would result
in a source water concentration
exceeding 0.01 oocysts/L. To avoid a
relatively small number of counts
determining an additional treatment
implication, unfiltered systems may
consider conducting more frequent
sampling or analyzing larger sample
volumes (e.g., 50 L). Since the water
sources of unfiltered systems tend to
have very low turbidity (compared to
average sources in filtered systems), it is
typically more feasible to analyze larger
sample volumes in unfiltered systems.
Filters have been approved for
Cryptosporidium analysis of 50 L
samples. Note that analysis of larger
sample volumes would not reduce the
required sampling frequency.
3. Request for Comment
EPA solicits comment on the
proposed monitoring and treatment
technique requirements for unfiltered
systems. Specifically, the Agency seeks
comment on the following issues:
Use of Two Disinfectants
EPA requests comment on the
proposed requirement for unfiltered
systems to use two disinfectants and for
each disinfectant to meet by itself the
inactivation requirement for at least one
regulated pathogen. The requirement for
unfiltered systems to use two
disinfectants was recommended by the
Advisory Committee because (1)
disinfectants vary in their efficacy
against different pathogens, so that the
use of multiple disinfectants can
provide more effective protection
against a broad spectrum of pathogens,
and (2) multiple disinfectants provide
multiple barriers of protection, which
can be more reliable than a single
disinfectant.
An alternate approach would be to
allow systems to meet the inactivation
requirements using any combination of
one or more disinfectants that achieved
the required inactivation level for all
pathogens. This would give systems
greater flexibility and could spur the
development of new disinfection
techniques that would be applicable to
a wide range of pathogens. However,
this approach might be less protective
against unregulated pathogens. A
related question is whether the
proposed requirements for use of two
disinfectants establish an adequate level
of multiple barriers in the treatment
provided by unfiltered systems.
Treatment Requirements for Unfiltered
Systems With Higher Cryptosporidium
Levels
Under the proposed LT2ESWTR, a
filtered system that measures a mean
source water Cryptosporidium level of
0.075 oocysts/L or higher is required to
provide a total of 4 log or more
reduction of Cryptosporidium. However,
if an unfiltered system, meeting the
criteria for avoiding filtration were to
measure Cryptosporidium at this level,
it would be required to provide only 3
log treatment. Available occurrence data
indicate that very few, if any, unfiltered
systems will measure mean source
water Cryptosporidium concentrations
above 0.075 oocysts/L. However, EPA
requests comment on whether or how
this possibility should be addressed.
G. Options for Systems To Meet
Cryptosporidium Treatment
Requirements
1, Microbial Toolbox Overview
The LT2ESWTR proposal contains a
list of treatment processes and
management practices for water systems
to use in meeting additional
Cryptosporidium treatment
requirements under the LT2ESWTR.
This list, termed the microbial toolbox,
was recommended by the Stage 2 M-
DBP Advisory Committee in the
Agreement in Principle. Components of
the microbial toolbox include watershed
control programs, alternative sources,
pretreatment processes, additional
filtration barriers, inactivation
technologies, and enhanced plant
performance. The intent of the microbial
toolbox is to provide water systems with
broad flexibility in selecting cost-
effective LT2ESWTR compliance
strategies. Moreover, the toolbox allows
systems that currently provide
additional pathogen barriers or that can
demonstrate enhanced performance to
receive additional Cryptosporidium
treatment credit.
A key feature of the microbial toolbox
is that many of the components cany
presumptive credits towards
Cryptosporidium treatment
requirements. Plants will receive these
credits for toolbox components by
demonstrating compliance with
required design and implementation
criteria, as described in the sections that
follow. Treatment credit greater than the
presumptive credit may be awarded for
a toolbox component based on a site-
specific or technology-specific
demonstration of performance, as
described in section IV.C.17.
While the Advisory Committee made
recommendations for the degree of
presumptive treatment credit to be
granted to different toolbox
components, the Committee did not
specify the design and implementation
conditions under which the credit
should be awarded. EPA has identified
and is proposing such conditions in
today's notice, based on an assessment
of available data. For certain toolbox
components, such as raw water storage
and roughing filters, the Agency
concluded that available data do not
support the credit recommended by the
Advisory Committee. Consequently,
EPA is not proposing a presumptive
credit for these options.
For each microbial toolbox
component, EPA is requesting comment
on: (1) Whether available data support
the proposed presumptive credits,
including the design and
implementation conditions under which
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the credit would be awarded, (2)
whether available data are consistent
with the decision not to award
presumptive credit for roughing filters
and raw water off-stream storage, and
(3) whether additional data are available
on treatment effectiveness of toolbox
components for reducing
Cryptosporidium levels. EPA will
consider modifying today's proposal for
microbial toolbox components based on
new information that may be provided.
EPA particularly solicits comment on
the performance of alternative filtration
technologies that are currently being
used, as well as ones that systems are
considering for use in the future,
specifically including bag filters,
cartridge filters, and bank filtration, in
removing Cryptosporidium. The Agency
requests both laboratory and field data
that will support a determination of the
appropriate level of Cryptosporidium
removal credit to award to these
technologies. In addition, the Agency
requests information on the
applicability of these technologies to
different source water types and
treatment scenarios. Data submitted in
response to this request for comment
should include, where available,
associated quality assurance and cost
information. This preamble discusses
bank filtration in section IV.C.6 and bag
and cartridge filters in section 1V.C.12.
Table IV-7 summarizes presumptive
credits and associated design and
implementation criteria for microbial
toolbox components. Each component is
then described in more detail in the
sections that follow. EPA is also
developing guidance to assist systems
with implementing toolbox
components. Pertinent guidance
documents include: UV Disinfection
Guidance Manual (USEPA 2003d),
Membrane Filtration Guidance Manual
(USEPA 2003e), and Toolbox Guidance
Manual (USEPA 2003f). Each is
available in draft form in the docket for
today's proposal (http://www.epa.gov/
edocket/).
TABLE IV-7— MICROBIAL TOOLBOX: PROPOSED OPTIONS, LOG CREDITS, AND DESIGN/IMPLEMENTATION CRITERIA
Toolbox option
Proposed Cryptosporidium log credit with design and implementation criteria1
0.5 log credit for State-approved program comprising EPA specified elements. Does
not apply to unfiltered systems.
No presumptive credit. Systems may conduct simultaneous monitoring for
LT2ESWTR bin classification at alternative intake locations or under alternative in-
take management strategies.
No presumptive credit. Systems using off-stream storage must conduct LT2ESWTR
sampling after raw water reservoir to determine bin classification,
0.5 log credit with continuous operation and coagulant addition; basins must achieve
0.5 log turbidity reduction based on the monthly mean of daily measurements in 11
of the 12 previous months; all flow must pass through basins. Systems using exist-
ing pre-sed basins must sample after basins to determine bin classification and are
not eligible for presumptive credit.
0.5 log additional credit for two-stage softening (single-stage softening is credited as
equivalent to conventional treatment). Coagulant must be present in both stages-
includes metal salts, polymers, lime, or magnesium precipitation. Both stages must
treat 100% of flow.
0.5 log credit for 25 ft. setback; 1.0 log credit for 50 ft. setback; aquifer must be un-
consolidated sand containing at least 10% fines; average turbidity in wells must be
< 1 NTU. Systems using existing wetls followed by filtration must monitor well efflu-
ent to determine bin classification and are not eligible for presumptive credit.
0.5 log credit for combined filter effluent turbidity < 0.15 NTU in 95% of samples
each month.
No presumptive credit proposed.
2.5 log credit as a secondary filtration step; 3.0 log credit as a primary filtration proc-
ess. No prior chlori nation.
0.5 log credit for second separate filtration stage; treatment train must include coagu-
lation prior to first filter. No presumptive credit for roughing filters.
Log credit equivalent to removal efficiency demonstrated in challenge test for device
if supported by direct integrity testing.
1 tog credit with demonstration of at least 2 log removal efficiency in challenge test.
2 log credit with demonstration of at least 3 log removal efficiency in challenge test.
Log credit based on demonstration of log inactivation using CT table.
Log credit based on demonstration of log inactivalion using CT table.
Log credit based on demonstration of inactivation with UV dose table; reactor testing
required to establish validated operating conditions.
1.0 log credit for demonstration of filtered water turbidity < 0.1 NTU in 95 percent of
daily max values from individual filters (excluding 15 min period following
backwashes) and no individual filter > 0.3 NTU in two consecutive measurements
taken 15 minutes apart.
Credit awarded to unit process or treatment train based on demonstration to the
State, through use of a State-approved protocol.
i Table provides summary information only; refer to following preamble and regulatory language for detailed requirements.
2. Watershed Control Program
a. What is EPA proposing today? EPA
is proposing a 0.5 log credit towards
Cryptosporidium treatment
requirements under the LT2ESWTR for
filtered systems that develop a State-
approved watershed control program
designed to reduce the level of
Cryptosporidium. The watershed
control program credit can be added to
the credit awarded for any other toolbox
component. However, this credit is not
available to unfiltered systems, as they
are currently required under 40 CFR
141.171 to maintain a watershed control
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program that minimizes the potential for
contamination by Cryptosporidium as a
criterion for avoiding filtration.
There are many potential sources of
Cryptosporidium in watersheds,
including sewage discharges and non-
point sources associated with animal
feces. The feasibility, effectiveness, and
sustainability of control measures to
reduce Cryptosporidium contamination
of water sources will be site-specific.
Consequently, the proposed watershed
control program credit centers on
systems working with stakeholders in
the watershed to develop a site-specific
program, and State review and approval
are required. In the Toolbox Guidance
Manual (USEPA 2003f), available in
draft in the docket for today's proposal,
EPA provides information on
management practices that systems may
consider in developing their watershed
control programs.
Initial State approval of a system's
watershed control program will be
based on State review of the system's
proposed watershed control plan and
supporting documentation. The initial
approval can be valid until the system
completes the second round of
Cryptosporidium monitoring described
in section IV.A (systems begin a second
round of monitoring six years after the
initial bin assignment). During this
period, the system is responsible for
implementing the approved plan and
complying with other general
requirements, such as an annual
watershed survey and program status
report. These requirements are further
described later in this section.
The period during which State
approval of a watershed control program
is in effect is referred to as the approval
period. Systems that want to continue
their eligibility to receive the 0.5 log
Cryptosporidium treatment credit must
reapply for State approval of the
program for each subsequent approval
period. In general, the re-approval will
be based on the State's review of the
system's reapplication package, as well
as the annual status reports and
watershed surveys. Subsequent
approval(s) by the State of the
watershed control program typically
will be for a time equivalent to the first
approval period, but States have the
discretion to renew approval for a
longer or shorter time period.
Requirements for Initial State Approval
of Watershed Control Programs
Systems that intend to pursue a 0.5
log Cryptosporidium treatment credit for
a watershed control program are
required to notify the State within one
year following initial bin assignment
that the system proposes to develop a
watershed control plan and submit it for
State approval.
The application to the State for initial
program approval must include the
following minimum elements:
• An analysis of the vulnerability of
each source to Cryptosporidium. The
vulnerability analysis must address the
watershed upstream of the drinking
water intake, including: A
characterization of the watershed
hydrology, identification of an "area of
influence" (the area to be considered in
future watershed surveys) outside of
which there is no significant probability
of Cryptosporidium or fecal
contamination affecting the drinking
water intake, identification of both
potential and actual sources of
Cryptosporidium contamination, the
relative impact of the sources of
Cryptosporidium contamination on the
system's source water quality, and an
estimate of the seasonal variability of
such contamination.
• An analysis of control measures
that could address the sources of
Cryptosporidium contamination
identified during the vulnerability
analysis. The analysis of control
measures must address their relative
effectiveness in reducing
Cryptosporidium loading to the source
water and their sustainability.
• A plan that specifies goals and
defines and prioritizes specific actions
to reduce source water Cryptosporidium
levels. The plan must explain how
actions are expected to contribute to
specified goals, identify partners and
their role(s), present resource
requirements and commitments
including personnel, and include a
schedule for plan implementation.
The proposed watershed control plan
and a request for program approval and
0.5 log Cryptosporidium treatment
credit must be submitted by the system
to the State no later than 24 months
following initial bin assignment.
The State will review the system's
initial proposed watershed control plan
and either approve, reject, or
"conditionally approve" the plan. If the
plan is approved, or if the system agrees
to implementing the State's conditions
for approval, the system will be
awarded 0.5 log credit towards
LT2ESWTR Cryptosporidium treatment
requirements. A final decision on
approval must be made no later than
three years following the system's initial
bin assignment.
The initial State approval of the
system's watershed control program can
be valid until the system completes the
required second round of
Cryptosporidium monitoring. The
system is responsible for taking the
required steps, described as follows, to
maintain State program approval and
the 0.5 log credit during the approval
period.
Requirements for Maintaining State
Approval of Watershed Control
Programs
Systems that have obtained State
approval of their watershed control
program are required to meet the
following ongoing requirements within
each approval period to continue their
eligibility for the 0.5 log
Cryptosporidium treatment credit:
• Submit an annual watershed
control program status report to the
State during each year of the approval
period.
• Conduct an annual State-approved
watershed survey and submit the survey
report to the State.
• Submit to the State an application
for review and re-approval of the
watershed control program and for a
continuation of the 0.5 log treatment
credit for a subsequent approval period.
The annual watershed control
program status report must describe the
system's implementation of the
approved plan and assess the adequacy
of the plan to meet its goals. It must
explain how the system is addressing
any shortcomings in plan
implementation, including those
previously identified by the State or as
the result of the watershed survey. If it
becomes necessary during
implementation to make substantial
changes in its approved watershed
control program, the system must notify
the State and provide a rationale prior
to making any such changes . If any
change is likely to reduce the level of
source water protection, the system
must also include the actions it will take
to mitigate the effects in its notification.
The watershed survey must be
conducted according to State guidelines
and by persons approved by the State to
conduct watershed surveys. The survey
must encompass the area of the
watershed that was identified in the
State-approved watershed control plan
as the area of influence and, as a
minimum, assess the priority activities
identified in the plan and identify any
significant new sources of
Cryptosporidium.
The application to the State for review
and re-approval of the system's
watershed control program must be
provided to the State at least six months
before the current approval period
expires or by a date previously
determined by the State. The request
must include a summary of activities
and issues identified during the
previous approval period and a revised
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plan that addresses activities for the
next approval period, including any
new actual or potential sources of
Cryptosporidium contamination and
details of any proposed or expected
changes from the existing State-
approved program. The plan must
address goals, prioritize specific actions
to reduce source water
Cryptosporidium, explain how actions
are expected to contribute to achieving
goals, identify partners and their role(s),
resource requirements and
commitments, and the schedule for plan
implementation.
The annual program status reports,
watershed control plan and annual
watershed sanitary surveys must be
made available to the public upon
request. These documents must be in a
plain language format and include
criteria by which to evaluate the success
of the program in achieving plan goals.
If approved by the State, the system may
withhold portions of the annual status
report, watershed control plan, and
watershed sanitary survey based on
security considerations.
b. How was this proposal developed?
The M-DBP Advisory Committee
recommended that systems be awarded
0.5 log Cryptosporidium treatment
credit for implementing a watershed
control program. This recommendation
was based on the Committee's
recognition that some systems will be
able to reduce the level of
Cryptosporidium in their source water
by implementing a well-designed and
focused watershed control program.
Moreover, the control measures used in
the watershed to reduce levels of
Cryptosporidium are likely to reduce
concentrations of other pathogens as
well.
EPA concurs that well designed
watershed control programs that focus
on reducing levels of Cryptosporidium
contamination of water sources should
be encouraged, and that implementation
of such programs will likely reduce
overall microbial risk. A broad
reduction in microbial risk will occur
through the application of control
measures and best management
practices that are effective in reducing
fecal contamination in the watershed. In
addition, plant management practices
may be enhanced by the knowledge
systems acquire regarding the watershed
and factors that affect microbial risk,
such as sources, fate, and transport of
pathogens.
Given the highly site-specific nature
of a watershed control program,
including the feasibility and
effectiveness of different control
measures, EPA believes that systems
should demonstrate their eligibility for
0.5 log Cryptosporidium treatment
credit by developing targeted programs
that account for site-specific factors. As
part of developing a watershed control
program, systems will be required to
assess a number of these factors,
including watershed hydrology, sources
of Cryptosporidium in the watershed,
human impacts, and fate and transport
of Cryptosporidium. Furthermore, EPA
believes that the State is well positioned
to judge whether a system's watershed
control program is likely to achieve a
substantial reduction of
Cryptosporidium in source water.
Consequently, EPA is proposing that
approval of watershed control programs
and allowance for an associated 0.5 log
treatment credit be made by the State on
a system specific basis.
A watershed control program could
include measures such as (1) the
elimination, reduction, or treatment of
wastewater or storm water discharges,
(2) treatment of Cryptosporidium
contamination at the sites of waste
generation or storage, (3) prevention of
Cryptosporidium migration from
sources, or (4) any other measures that
are effective, sustainable, and likely to
reduce Cryptosporidium contamination
of source water. EPA recognizes that
many public water systems do not
directly control the watersheds of their
sources of supply. EPA expects that
systems will need to develop and
maintain partnerships with landowners
within watersheds, as well as with State
governments and regional agencies that
have authority over activities in the
watershed that may contribute
Cryptosporidium to the water supply.
Stakeholders that have some level of
control over activities that could
contribute to Cryptosporidium
contamination include municipal
government and private operators of
wastewater treatment plants, livestock
farmers and persons who spread
manure, individuals with failing septic
systems, logging operations, and other
government and commercial
organizations.
EPA has initiated a number of
programs that address watershed
management and source water
protection. In 2002, EPA launched the
Watershed Initiative (67 FR 36172, May
23, 2002) (USEPA 2002b), which will
provide grants to support innovative
watershed based approaches to
preventing, reducing, and eliminating
water pollution. In addition, EPA has
recently promulgated new regulations
for Concentrated Animal Feeding
Operations (CAFOs), which through the
NPDES permit process will limit
discharges that contribute microbial
pathogens to watersheds.
SDWA section 1453 requires States to
carry out a source water quality
assessment program for the protection
and benefit of public water systems.
EPA issued program guidance in August
of 1997, and expects that most States
will complete their source water
assessments of surface water systems by
the end of 2003. These assessments will
establish a foundation for watershed
vulnerability analyses by providing the
preliminary analyses of watershed
hydrology, a starting point for defining
the area of influence, and an inventory
and hierarchy of actual and potential
contamination sources. In some cases,
these portions of the source water
assessment may fully satisfy those
analytical needs.
As noted earlier, EPA has published
and is continuing to develop guidance
material that addresses contamination
by Cryptosporidium and other
pathogens from both non-point sources
(e.g., agricultural and urban runoff,
septic tanks) and point sources (e.g.,
sewer overflows, POTWs, CAFOs). The
Toolbox Guidance Manual, available in
draft with today's proposal, includes a
list of programmatic resources and
guidance available to assist systems in
building partnerships and implementing
watershed protection activities. In
addition, this guidance manual
incorporates available information on
the effectiveness of different control
measures to reduce Cryptosporidium
levels and provides case studies of
watershed control programs. This
guidance is intended to assist water
systems in developing their watershed
control programs and States in their
assessment and approval of these
programs.
In addition to guidance documents,
demonstration projects, and technical
resources, EPA provides funding for
watershed and source water protection
through the Drinking Water State
Revolving Fund (DWSRF) and Clean
Water State Revolving Fund (CWSRF).
Under the DWSRF program, States may
provide funding directly to public water
systems for source water protection,
including watershed management and
pathogen source reduction plans.
CWSRF funds have been used to
develop and implement agricultural best
management practices for reducing
pathogen loading to receiving waters
and to fund directly, or provide
incentives for, the replacement of failing
septic systems. EPA encourages the use
of CWSRF for source protection and has
developed guidelines for the award of
funds to address non-point sources of
pollution (CWA section 319 Non Point
Source Pollution Program). Further, the
Agency is promoting the broader use of
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SRF funds to implement measures to
prevent and control non-point source
pollution. Detailed sanitary surveys,
with a specific analysis of sources of
Cryptosporidium in the watershed, will
facilitate the process of targeting
funding available under SRF programs
to eliminate or mitigate these sources.
c. Request for comment. EPA requests
comment on the proposed watershed
control program credit and associated
program components.
• Should the State be allowed to
reduce the frequency of the annual
watershed survey requirement for
certain systems if systems engage in
alternative activities like public
outreach?
• The effectiveness of a watershed
control program may be difficult to
assess because of uncertainty in the
efficacy of control measures under site-
specific conditions. In order to provide
constructive guidance, EPA welcomes
reports on scientific case studies and
research that evaluated methods for
reducing Cryptosporidium
contamination of source waters.
• Are there confidential business
information (CBI) concerns associated
with making information on the
watershed control program available to
the public? If so, what are these
concerns and how should they be
addressed?
• How should the "area of influence"
(the area to be considered in future
watershed surveys) be delineated,
considering the persistence of
Cryptosporidium?
3. Alternative Source
a. What is EPA proposing today? Plant
intake refers to the works or structures
at the head of a conduit through which
water is diverted from a source (e.g.,
river or lake) into the treatment plant.
Plants may be able to reduce influent
Cryptosporidium levels by changing the
intake placement (either within the
same source or to an alternate source) or
managing the timing or level of
withdrawal.
Because the effect of changing the
location or operation of a plant intake
on influent Cryptosporidium levels will
be site specific, EPA is not proposing
any presumptive credit for this option.
Rather, if a system is concerned that
Cryptosporidium levels associated with
the current plant intake location and/or
operation will result in a bin assignment
requiring additional treatment under the
LT2ESWTR, the system may conduct
concurrent Cryptosporidium monitoring
reflecting a different intake location or
different intake management strategy.
The State will then make a
determination as to whether the plant
may be classified in an LT2ESWTR bin
using the alternative intake location or
management monitoring results.
Thus, systems that intend to be
classified in an LT2ESWTRbin based
on a different intake location or
management strategy must conduct
concurrent Cryptosporidium
monitoring. The system is still required
to monitor its current plant intake in
addition to any alternative intake
location/management monitoring, and
must submit the results of all
monitoring to the State. In addition, the
system must provide the State with
supporting information documenting
the conditions under which the
alternative intake location/management
samples were collected. The concurrent
monitoring must conform to the sample
frequency, sample volume, analytical
method, and other requirements that
apply to the system for Cryptosporidium
monitoring as stated in Section IV.A.l.
If a plant's LT2ESWTR bin
classification is based on monitoring
results reflecting a different intake
location or management strategy, the
system must relocate the intake or
implement the intake management
strategy within the compliance time
frame for the LT2ESWTR, as specified
in section IV.F.
b. How was this proposal developed?
In the Stage 2 M-DBP Agreement in
Principle, the Advisory Committee
identified several actions related to the
intake which potentially could reduce
the concentration of Cryptosporidium
entering a treatment plant. These
actions were included in the microbial
toolbox under the heading Alternative
Source, and include: (1) Intake
relocation, (2) change to alternative
source of supply, (3) management of
intake to reduce capture of oocysts in
source water, (4) managing timing of
withdrawal, and (5) managing level of
withdrawal in water column.
It is difficult to predict in advance the
efficacy of any of these activities in
reducing levels of Cryptosporidium
entering the treatment plant. However,
if a system relocates the plant intake or
implements a different intake
management strategy, it is appropriate
for the plant to be assigned to an
LT2ESWTR bin using monitoring results
reflecting the new intake strategy.
EPA believes that the requirements
specified for monitoring to determine
•bin placement are necessary to
characterize a plant's mean source water
Cryptosporidium level. Consequently,
any concurrent monitoring carried out
to characterize a different intake
location or management strategy should
be equivalent. For this reason, the
sampling and analysis requirements
which apply to the current intake
monitoring also apply to any concurrent
monitoring used to characterize a new
intake location or management strategy.
EPA also recognizes that if plant's bin
assignment is based on a new intake
operation strategy then it is important
for the plant to continue to use this new
strategy in routine operation. Therefore,
EPA is proposing that the system
document the new intake operation
strategy when submitting additional
monitoring results to the State and that
the State approve that new strategy.
c. Request for comment. EPA requests
comment on the following issues:
* What are intake management
strategies by which systems could
reduce levels of Cryptosporidium in the
plant influent?
• Can representative Cryptosporidium
monitoring to demonstrate a reduction
in oocyst levels be accomplished prior
to implementation of a new intake
strategy (e.g., monitoring a new source
prior to constructing a new intake
structure)?
• How should this option be applied
to plants that use multiple sources
which enter a plant through a common
conduit, or which use separate sources
which enter the plant at different
points?
4. Off-Stream Raw Water Storage
a. What is EPA proposing today? Off-
stream raw water storage reservoirs are
basins located between a water source
(typically a river) and the coagulation
and filtration processes in a treatment
plant. EPA is not proposing
presumptive treatment credit for
Cryptosporidium removal through off-
stream raw water storage. Systems using
off-stream raw water storage must
conduct Cryptosporidium monitoring
after the reservoir for the purpose of
determining LT2ESWTR bin placement.
This will allow reductions in
Cryptosporidium levels that occur
through settling during off-stream
storage to be reflected in the monitoring
results and consequent LT2ESWTR bin
assignment.
The use of off-stream raw water
storage reservoirs during LT2ESWTR
monitoring must be consistent with
routine plant operation and must be
recorded by the system. Guidance on
monitoring locations is provided in
Public Water System Guidance Manual
for Source Water Monitoring under the
LT2ESWTR (USEPA 2003g), which is
available in draft in the docket for
today's proposal.
b. How was this proposal developed?
The Stage 2 M-DBP Agreement in
Principle recommends a 0.5 log credit
for off-stream raw water storage
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reservoirs with detention times on the
order of days and 1.0 log credit for
reservoirs with detention times on the
order of weeks. After a review of the
available literature, EPA is unable to
determine criteria that provide
reasonable assurance of achieving a 0.5
or 1 log removal of oocysts.
Consequently, EPA is not proposing a
presumptive treatment credit for this
process.
This proposal for off-stream raw water
storage represents a change from the
November 2001 pre-proposal draft of the
LT2ESWTR (USEPA 2001g), which
described 0.5 log and 1 log presumptive
credits for reservoirs with hydraulic
detention times of 21 and 60 days,
respectively. These criteria were based
on a preliminary assessment of reported
studies, described later in this section,
that evaluated Cryptosporidium and
Giardia removal in raw water storage
reservoirs.
Subsequent to the November 2001
pre-proposal draft, the Science Advisory
Board (SAB) reviewed the data that EPA
had acquired to support
Cryptosporidium treatment credits for
off-stream raw water storage (see section
VII.K). In written comments from a
December 2001 meeting of the SAB
Drinking Water Committee, the panel
concluded that the available data were
not adequate to demonstrate the
treatment credits for off-stream raw
water storage described in the pre-
proposal draft, and recommended that
no presumptive credits be given for this
toolbox option. The panel did agree,
though, that a utility should be able to
take advantage of off-stream raw water
storage by sampling after the reservoir
for appropriate bin placement. EPA
concurs with this finding by the SAB
and today's proposal is consistent with
their recommendation.
Off-stream raw water storage can
improve the microbial quality of water
in a number of ways. These include (1)
reduced microbial and particulate
loading to the plant due to settling in
the reservoir, (2) reduced viability of
pathogens due to die-off, and (3)
dampening of water quality and
hydraulic spikes. EPA has evaluated a
number of studies that investigated the
removal of Cryptosporidium and other
microorganisms and particles in raw
water storage basins. These studies are
summarized in the following
paragraphs, and selected results are
presented in Table IV-8.
TABLE IV-8.—STUDIES OF Cryptosporidium AND GIARDIA REMOVAL FROM OFF-STREAM RAW WATER STORAGE
Researcher
Reservoir
Residence time
Log reductions
Ketelaars et al. 1995
Van Breeman et al. 1998
Bertolucci et al. 1998
Ongerth, 1989
Biesbosch reservoir system: man-
made pumped storage (Nether-
lands).
Biesbosch reservoir system: man-
made pumped storage (Nether-
lands).
PWN (Netherlands)
Abandoned gravel quarry used for
storage (Italy).
Three impoundments on rivers with
limited public access (Seattle,
WA).
24 weeks (average)
24 weeks (average)
10 weeks (average)
18 days (theoretical)
40, 100 and 200 days (re-
spectively).
Cryptosporidium-^ .4 Giardia-2.3.
Cryptosporidium-2.0 G/ard/a-2.6.
Cryptosporidium^ .3 G/ard/a-0.8.
Cryptosporidium-'l .0 G/ard/a-0.8.
No Giardia removal observed.
Ketelaars et al. (1995) evaluated
Cryptosporidium and Giardia removal
across a series of three man-made
pumped reservoirs, named the
Biesbosch reservoirs, with reported
hydraulic retention times of 11, 9, and
4 weeks (combined retention time of 24
weeks). To prevent algal growth and
hypolimnetic deoxygenation, the
reservoirs were destratified by air-
injection. Based on weekly sampling
over one year, mean influent and
effluent concentrations of
Cryptosporidium were 0.10 and 0.004
oocysts/100 L, respectively, indicating
an average removal across the three
reservoirs of 1.4 log. Mean removal of
Giardia was 2.3 log.
Van Breemen et al. (1998) continued
the efforts of Ketelaars et al. (1995) in
evaluating pathogen removal across the
Biesbosch reservoir system. Using a
more sensitive analytical method, Van
Breeman et al. measured mean
Cryptosporidium levels of 6.3 and 0.064
oocysts/100 L at the inlet and outlet,
respectively, indicating an average
removal of 2.0 log. For Giardia, the
average reduction was 2.6 log. In
addition, Van Breeman et al. (1998)
evaluated removal of Cryptosporidium,
Giardia, and other microorganisms in a
reservoir designated PWN, which had a
hydraulic retention time of 10 weeks.
Passage through this storage reservoir
was reported to reduce the mean
concentration of Cryptosporidium by 1.3
log and of Giardia by 0.8 log.
Bertolucci et al. (1998) investigated
removal of Cryptosporidium, Giardia,
and nematodes in a reservoir derived
from an abandoned gravel quarry with
a detention time reported as around 18
days. Over a 2 year period, average
influent and effluent concentrations of
Cryptosporidium were 70 and 7 oocysts/
100 L, respectively, demonstrating a
mean reduction of 1 log. Average
Giardia levels decreased from 137 cysts/
100L in the inlet to 46 cysts/lOOL at the
outlet, resulting in a mean 0.5 log
removal.
Ongerth (1989) studied concentrations
of Giardia cysts in the Tolt, Cedar, and
Green rivers, which drain the western
slope of the Cascade Mountains in
Washington. The watersheds of each
river are controlled by municipal water
departments for public water supply,
and public access is limited. The Cedar,
Green, and Tolt rivers each have
impoundments with reported residence
times of 100, 30-50, and 200 days,
respectively, in the reach studied.
Ongerth found no statistically
significant difference in cyst
concentrations above and below any of
the reservoirs. Median cyst
concentrations above and below the
Cedar, Green, and Tolt reservoirs were
reported as 0.12 and 0.22, 0.27 and 0.32,
and 0.16 and 0.21 cysts/L, respectively.
It is unclear why no decrease in cyst
levels was observed. It is possible that
contamination of the water in the
impoundments by Giardia from animal
sources, either directly or through run-
off, may have occurred.
EPA has also considered results from
studies which evaluated the rate at
which Cryptosporidium oocysts lose
viability and infectivity over time. Two
studies are summarized next, with
selected results presented in Table IV-
9.
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47687
TABLE IV-9.—STUDIES OF Cryptosporidium DIE-OFF DURING RAW WATER STORAGE
Researcher
Medema et al. 1997
Sattar ef a/. 1999
Type of experiment
bacteria and incubated.
ers inoculated with Giardia and Cryptosporidium.
Log reduction
tion over 20-80 days at 15 °C.
30 days at 20 °C. Little reduction at 4 °C. In situ con-
ditions showed 0,4 to 1.5 log reduction at 21 days.
Medema et al. (1997) conducted
bench scale studies of the influence of •
temperature and the presence of
biological activity on the die-off rate of
Cryptosporidium oocysts. Die-off rates
were determined at 5°C and 15°C, and
in both natural and sterilized
(autoclaved) river water. Both
excystation and vital dye staining were
used to determine oocyst viability. At
5°C, the die-off rate under all conditions
was 0.010 logio/day, assuming first-
order kinetics. This translates to 0.5 log
reduction at 50 days. At 15°C, the die-
off rate in natural river water
approximately doubled to 0.024 logic/
day (excystation) and 0.018 logic/day
(dye staining). However, in autoctaved
water at 15°C, the die-off rate was only
0.006 logio/day (excystation) and 0.011
logio/day (dye staining). These results
suggest that oocyst die-off is more rapid
at higher temperatures in natural water,
and this behavior may be caused by
increased biological or biochemical
activity.
Sattar et al. (1999) evaluated factors
impacting Cryptosporidium and Giardia
survival. Microtubes containing
untreated water from the Grand and St.
Lawrence rivers (Ontario) were
inoculated with purified oocysts and
cysts. Samples were incubated at
temperatures ranging from 4°C to 30°C,
viability of oocysts and cysts was
measured by excystation. At 20°C and
30°C, reductions in viable
Cryptosporidium oocysts ranged from
approximately 0.6 to 2.0 log after 30
days. However, relatively little
inactivation took place when oocysts
were incubated at 4°C (as low as 0.2 log
at 100 days).
To evaluate oocyst survival under
dynamic environmental conditions,
Sattar et al. seeded dialysis cassettes
with Cryptosporidium oocysts and
placed them in overflow tanks receiving
water from different rivers in Canada
and the United States. Reductions in the
concentration of viable oocysts ranged
from approximately 0.4 to 1.5 log after
21 days. Survival of oocysts was
enhanced by pre-filtering the water,
suggesting that microbial antagonism
was involved in the natural inactivation
of the parasites.
Overall these studies indicate that off-
stream storage of raw water has the
potential to effect significant reductions
in the concentration of viable
Cryptosporidium oocysts, both through
sedimentation and degradation of
oocysts (i.e., die-off). However, these
data also illustrate the challenge in
reliably estimating the amount of
removal that will occur in any particular
storage reservoir. Removal and die-off
rates reported in these studies varied
widely, and were observed to be
influenced by factors like temperature,
contamination, hydraulic short
circuiting, and biological activity (Van
Breeman et al. 1998, Medema et al.
1997, Sattar et al. 1999). Because of this
variability and the relatively small
amount of available data, it is difficult
to extrapolate from these studies to
develop nationally applicable criteria
for awarding removal credits to raw
water storage.
c. Bequest for comment. EPA requests
comment on the finding that the
available data are not adequate to
support a presumptive Cryptosporidium
treatment credit for off-stream raw water
storage, and that systems using off-
stream storage should conduct
LT2ESWTR monitoring at the reservoir
outlet. This monitoring approach would
account for reductions in oocyst
concentrations due to settling, but
would not provide credit for die-off,
since non-viable oocysts could still be
counted during monitoring. In addition,
EPA would also appreciate comment on
the following specific issues:
• Is additional information available
that either supports or suggests
modifications to this proposal
concerning off-stream raw water
storage?
• How should a system address the
concern that water in off-stream raw
water storage reservoirs may become
contaminated through processes like
algal growth, run-off, roosting birds, and
activities on the watershed?
5. Pre-Sedimentation With Coagulant
a. What is EPA proposing today?
Presedimentation is a preliminary
treatment process used to remove
particulate material from the source
water before the water enters primary
sedimentation and filtration processes
in a treatment plant. EPA is proposing
to award a presumptive 0.5 log
Cryptosporidium treatment credit for
presedimentation that is installed after
LT2ESWTR monitoring and meets the
following three criteria:
(1) The presedimentation basin must
be in continuous operation and must
treat all of the flow reaching the
treatment plant.
(2) The system must continuously add
a coagulant to the presedimentation
basin.
(3) The system must demonstrate on
a monthly basis at least 0.5 log
reduction of influent turbidity through
the presedimentation process in at least
11 of the 12 previous consecutive
months. This monthly demonstration of
turbidity reduction must be based on
the arithmetic mean of at least daily
turbidity measurements in the
presedimentation basin influent and
effluent, and must be calculated as
follows:
Monthly mean turbidity log reduction =
Iogio(monthly mean of daily
influent turbidity) — logio(monthly
mean of daily effluent turbidity).
If the presedimentation process has not
been in operation for 12 months, the
system must verify on a monthly basis
at least 0.5 log reduction of influent
turbidity through the presedimentation
process, calculated as specified in this
paragraph, for at least all but any one of
the months of operation.
Systems with presedimentation in
place at the time they begin LT2ESWTR
Cryptosporidium monitoring are not
eligible for the 0.5 log presumptive
credit and must sample after the basin
when in use for the purpose of
determining their bin assignment. The
use of presedimentation during
LT2ESWTR monitoring must be
consistent with routine plant operation
and must be recorded by the system.
Guidance on monitoring is provided in
Public Water System Guidance Manual
for Source Water Monitoring under the
LT2ESWTR (USEPA 2003g), which is
available in draft in the docket for
today's proposal.
b. How was this proposal developed?
Presedimentation is used to remove
gravel, sand, and other gritty material
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from the raw water and dampen particle
loading to the rest of the treatment
plant. Presedimentation is similar to
conventional sedimentation, except that
presedimentation may be operated at
higher loading rates and may not
involve use of chemical coagulants.
Also, some systems operate the
presedimentation process periodically
and only in response to periods of high
particle loading.
Because presedimentation reduces
particle concentrations, it is expected to
reduce Cryptosporidium levels. In
addition, by dampening variability in
source water quality, presedimentation
may improve the performance of
subsequent treatment processes. In
general, the efficacy of presedimentation
in lowering particle levels is influenced
by a number of water quality and
treatment parameters including surface
loading rate, temperature, particle
concentration, coagulation, and
characteristics of the sedimentation
basin.
' The Stage 2-M-DBP Agreement in
Principle recommends 0.5 log
presumptive Cryptosporidium treatment
credit for presedimentation with the use
of coagulant. Today's proposal is
consistent with this recommendation.
However, the proposed requirement for
demonstrated turbidity reduction as a
condition for presedimentation credit
represents a change from the November
2001 pre-proposal draft of the
LT2ESWTR (USEPA 2001g). Rather than
a requirement for turbidity removal, the
2001 pre-proposal draft included
criteria for maximum overflow rate and
minimum influent turbidity as
conditions for the 0.5 log
presedimentation credit.
The Science Advisory Board (SAB)
reviewed the criteria and supporting
information for presedimentation credit
in the November 2001 pre-proposal
draft (see section VII.K). In written
comments from a December 2001
meeting of the SAB Drinking Water
Committee, the panel concluded that
available data were minimal to support
a 0.5 log presumptive credit and
recommended that no credit be given for
presedimentation. Additionally, the
panel stated thai performance criteria
other than overflow rate need to be
included if credit is to be given for
presedimentati on.
Due to this finding by the SAB, EPA
further reviewed data on removal of
aerobic spores (as an indicator of
Cryptosporidium removal) and turbidity
in full-scale presedimentation basins.
As shown later in this section, these
data indicate that presedimentation
basins achieving a monthly mean
reduction in turbidity of at least 0.5 log
have a high likelihood of reducing mean
Cryptosporidium levels by 0.5 log or
more. Consequently, EPA has
determined that it is appropriate to use
turbidity reduction as a performance
criterion for awarding Cryptosporidium
treatment credit to presedimentation
basins. The Agency believes this
performance criterion addresses the
concerns raised by the SAB.
The Agency has concluded that it is
appropriate to limit eligibility for the 0.5
log presumptive Cryptosporidium
treatment credit to systems that install
presedimentation after LT2ESWTR
monitoring. Systems with
presedimentation in place prior to
initiation of LT2ESWTR
Cryptosporidium monitoring may
sample after the presedimentation basin
to determine their bin assignment. In
this case, the effect of presedimentation
in reducing Cryptosporidium levels will
be reflected in the monitoring results
and bin assignment. Systems that
monitor after presedimentation are not
subject to the operational and
performance requirements associated
with the 0.5 log credit. The SAB agreed
that a system should be able to sample
after the presedimentation treatment
process for appropriate bin placement.
In considering criteria for awarding
Cryptosporidium removal credit to
presedimentation, EPA has evaluated
both published studies and data
submitted by water systems using
presedimentation. There is relatively
little published data on the removal of
Cryptosporidium by presedimentation.
Consequently, EPA has reviewed
studies that investigated
Cryptosporidium removal by
conventional sedimentation basins.
These studies are informative regarding
potential levels of performance, the
influence of water quality parameters,
and correlation of Cryptosporidium
removal with removal of potential
surrogates. However, removal efficiency
in conventional sedimentation basins
may be greater than in presedimentation
due to lower surface loading rates,
higher coagulant doses, and other
factors. To supplement these studies,
EPA has evaluated data provided by
utilities on removal of other types of
particles, primarily aerobic spores, in
the presedimentation processes of full
scale plants. Data indicate that aerobic
spores may serve as a surrogate for
Cryptosporidium removal by
sedimentation (Dugan et al. 2001).
i. Published studies of
Cryptosporidium removal by
conventional sedimentation basins.
Table IV-10 summarizes results from
published studies of Cryptosporidium
removal by conventional sedimentation
basins.
TABLE IV-10.—SUMMARY OF PUBLISHED STUDIES OF Cryptosporidium REMOVAL BY CONVENTIONAL SEDIMENTATION
BASINS
Authors)
States et al (1997)
Kelly et al (1995)
Patania et al. (1995)
Plant/process type
Full scale conventional with primary and secondary
sedimentation.
Full scale conventional (2 plants)
Full scale conventional (two stage lime softening)
Full scale conventional (two stage sedimentation)
Pilot scale conventional {3 plants)
Cryptosporidium removal by sedi-
mentation
0.6 to 1.6 tog (average 1.3 log).
0.41 log.
0.8 to 1.2 log.
3.8 log and 0.7 log.
0.8 log.
0.5 log.
2.0 log (median).
Dugan et al (2001) evaluated the
ability of conventional treatment to
control Cryptosporidium under different
water quality and treatment conditions
on a small pilot scale plant that had
been demonstrated to provide
equivalent performance to a larger plant.
Under optimal coagulation conditions,
oocyst removal across the sedimentation
basin ranged from 0.6 to 1.6 log,
averaging 1.3 log. Suboptimal
coagulation conditions (underdosed
relative to jar test predictions)
significantly reduced plant performance
with oocyst removal in the
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47689
sedimentation basin averaging 0.20 log.
Removal of aerobic spores, total particle
counts, and turbidity all correlated well
with removal of Cryptosporidium by
sedimentation.
States etal (1997) monitored
Cryptosporidium removal at the
Pittsburgh Drinking Water Treatment
Plant (65-70 million gallons per day
(MGD)). The clarification process
included ferric chloride coagulation,
flocculation, and settling in both a small
primary basin and a 120 MG secondary
sedimentation basin. Geometric mean
Cryptosporidium levels in the raw and
settled water were 31 and 12 oocysts/
100 L, respectively, indicating a mean
reduction of 0.41 log.
Edzwald and Kelly (1998) conducted
a bench-scale study to determine the
optimal coagulation conditions with
different coagulants for removing
Cryptosporidium oocysts from spiked
raw waters. Under optimal coagulation
conditions, the authors observed oocysts
reductions through sedimentation
ranging from 0.8 to 1.2 log.
Payment and Franco (1993) measured
Cryptosporidium and other
microorganisms in raw, settled, and
filtered water samples from drinking
water treatment plants in the Montreal
area. The geometric mean of raw and
settled water Cryptosporidium levels in
one plant were 742 and 0.12 oocysts/
100 L, respectively, suggesting a mean
removal of 3.8 log. In a second plant,
mean removal by sedimentation was
reported as 0.7 log, with raw and settled
water Cryptosporidium levels reported
as <2 and <0.2 oocysts/L, respectively.
Kelley et al. (1995) monitored
Cryptosporidium levels in the raw,
settled, and filtered water of two water
treatment plants (designated site A and
B). Both plants included two-stage
sedimentation. At site A, mean raw and
settled water Cryptosporidium levels
were 60 and 9.5 oocysts/100 L,
respectively, suggesting a mean removal
of 0.8 log by sedimentation. At site B,
mean raw and settled water
Cryptosporidium levels were 53 and 16
oocysts/100 L, respectively, for an
average removal by sedimentation of 0.5
log. Well water was intermittently
blended in the second stage of
sedimentation at site B, which may have
reduced settled and filtered water
pathogen levels.
Patania et al. (1995) evaluated
removal of Cryptosporidium in four
pilot scale plants. Three of these were
conventional and one used in-line
filtration (rapid mix followed by
filtration). Cryptosporidium removal
was generally 1.4 to 1.8 log higher in the
process trains with sedimentation
compared to in-line filtration. While the
effectiveness of sedimentation for
organism removal varied widely under
the conditions tested, the median
removal of Cryptosporidium by
sedimentation was approximately 2.0
log.
ii. Data supplied by utilities on the
removal of spores by presedimentation.
Data on the removal of Cryptosporidium
and spores (Bacillus subtilis and total
aerobic spores) during operation of full-
scale presedimentation basins were
collected independently and reported
by three utilities: St. Louis, MO, Kansas
City, MO, and Cincinnati, OH.
Cryptosporidium oocysts were not
detected in raw water at these locations
at levels sufficient to calculate log
removals of oocysts directly. However,
aerobic spores were present in the raw
water of these utilities at high enough
concentrations to measure log removals
through presedimentation as a surrogate
for Cryptosporidium removal. As noted
earlier, data from Dugan et al. (2001)
demonstrate a correlation between
removal of aerobic spores and
Cryptosporidium through sedimentation
under optimal coagulation conditions. A
summary of the spore removal data
supplied by the these utilities is shown
in Table rV-11.
TABLE IV-11 .—MEAN SPORE RE-
MOVAL FOR FULL-SCALE
PRESEDIMENTATION BASINS RE-
PORTED BY THREE UTILITIES
Reporting utility
St. Louis Water Divi-
sion.
Kansas City Water
Services Depart-
ment.
Cincinnati Water
Works.
Mean spore removal
1.1 log (B. subtilis).
0.8 log (B. subtilis)
(with coagulant).
0.46 log
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Federal Register/Vol. 68, No. 154/Monday, August 11, 2003/Proposed Rules
EPA also has concluded that
presedimentation basins need to be
operated continuously and treat 100%
of the plant flow in order to reasonably
ensure that the process will reduce
influent Cryptospondium levels by at
least 0.5 log over the course of a full
year. The Agency recognizes that,
depending on influent water quality,
some systems may determine it is more
prudent to operate presedimentation
basins intermittently in response to
fluctuating turbidity levels. By
proposing these conditions for the
presumptive presedimentation credit,
EPA is not recommending against
intermittent operation of
presedimentation basins. Rather, EPA is
attempting to identify the conditions
under which a 0.5 log presumptive
credit for presedimentation is
warranted.
In response to the SAB panel
recommendation that performance
criteria other than overflow rate be
included if credit is to ha given for
presedimentation, EPA analyzed the
relationship between removal of spores
and reduction in turbidity through
presedimentation for the three utilities
that supplied these data. Results of this
analysis are summarized in Table IV-12,
which shows the relationship between
monthly mean turbidity reduction and
the percent of months when mean spore
removal was at least 0.5 log.
BILLING CODE 6560-50-P
Table IV-12.- Relationship Between Mean Turbidity Reduction and the
Percent of Months When Mean Spore Removal Was at Least 0.5 Log
Log Reduction in Turbidity
(monthly mean)
>=0.1
>=0.2
>=0.3
>=0.4
>=0.5
>=0.6
>=0.7
>=0.8
>=0.9
>=1.0
Percent of Months with at least 0.5 Log Mean
Reduction in Spores
64%
68%
73%
78%
89%
91 %
90%
89%
95%
96%
Source: Data from Cincinnati Water Works, Kansas City Water Services Department, and St. Louis Water Division
BILLING CODE 6560-50-C
Within the available data set,
achieving a mean turbidity reduction of
at least 0.5 log appears to provide
approximately a 90% assurance that
average spore removal will be 0.5 log or
greater. The underlying data are shown
graphically in Figure IV-4. Based on
this information, EPA has concluded
that it is appropriate to require 0.5 log
turbidity reduction, determined as a
monthly mean of daily turbidity
readings, as an operating condition for
the 0.5 log presumptive
Cryptospondium treatment credit for
presedimentation. Further, EPA is
proposing that systems must meet the
0.5 log turbidity reduction requirement
in at least 11 of the 12 previous months
on an ongoing basis to remain eligible
for the presedimentation credit.
BILLING CODE 6560-50-P
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Federal Register/Vol. 68, No. 154/Monday, August 11, 2003/Proposed Rules
47691
f
E
o
o
|
w
K
«l
JS
O
;
J
^
* *•
•0.5 •<
*
*
*
* * ^
* / <• **» *
* A * * *
> «|'V * *
* * 4 *
^
0.5 1 1.5 2 2.5
*
Monthly Mean Log Removal of Turbidity
Figure IV-4.~ Monthly Mean Log Removal of Spores from Presedimentation vs.
Monthly Mean Turbidity Log Reduction
BILLING CODE 6560-5&-C
c. Request for comment. EPA requests
comment on the proposed criteria for
awarding credit to presedimentation.
EPA would particularly appreciate
comment on the following issues:
• Whether the information cited in
this proposal supports the proposed
credit forpresedimentation and the
operating conditions under which the
credit will be awarded;
* Additional information that either
supports or suggest modifications to the
proposed performance criteria and
presumptive credit;
• Today's proposal requires systems
using presedimentation to sample after
the presedimentation basin, and these
systems are not eligible to receive
additional presumptive
Cryptosporidium removal credit for
presedimentation. However, systems are
also required to collect samples prior to
chemical treatment, and EPA recognizes
that some plants provide chemical
treatment to water prior to, or during,
presedimentation. EPA requests
comment on how this situation should
be handled under the LT2ESWTR.
• Whether and under what conditions
factors like low turbidity raw water,
infrequent sludge removal, and wind
would make compliance with the 0.5
log turbidity removal requirement
infeasibie.
6. Bank Filtration
a. What is EPA proposing today? EPA
is proposing to award additional
Cryptosporidium treatment credit (0.5 or
1.0 log) for systems that implement bank
filtration as a pre-treatment technique if
it meets the design criteria specified in
this section. To be eligible for credit as
a pre-treatment technique, bank
filtration collection devices must meet
the following criteria:
• Wells are drilled in an
unconsolidated, predominantly sandy
aquifer, as determined by grain-size
analysis of recovered core material—the
recovered core must contain greater
than 10% fine-grained material (grains
less than 1.0 mm diameter) in at least
90% of its length;
• Wells are located at least 25 feet (in
any direction) from the surface water
source to be eligible for 0.5 log credit;
wells located at least 50 feet from the
source surface water are eligible for 1.0
log credit;
• The wellhead must be continuously
monitored for turbidity to ensure that no
system failure is occurring. If the
monthly average of daily maximum
turbidity values exceeds 1 NTU then the
system must report this finding to the
State. The system must also conduct an
assessment to determine the cause of the
high turbidity levels in the well and
consult with the State regarding
whether previously allowed credit is
still appropriate.
Systems using existing bank filtration
as pretreatment to a filtration plant at
the time the systems are required to
conduct Cryptosporidium monitoring,
as described in section IV.A, must
sample the well effluent for the purpose
of determining bin classification. Where
bin classification is based on monitoring
the well effluent, systems are not
eligible to receive additional credit for
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Federal Register/Vol. 68, No. 154/Monday, August 11. 2003/Proposed Rules
bank filtration. In these cases, the
performance of the bank filtration
process in reducing Cryptosporidium
levels will be reflected in the
monitoring results and bin
classification.
Systems using bank filtered water
without additional filtration typically
must collect source water samples in the
surface water (i.e., prior to bank
filtration) to determine bin
classification. This applies to systems
using bank filtration to meet the
Cryptosporidium removal requirements
of the IESWTR or LTlESWTR under the
provisions for alternative filtration
demonstration in 40 CFR 141.173(b) or
141.552(a). Note that the proposed bank
filtration criteria for Cryptosporidium
removal credit under the LT2ESWTR do
not apply to existing State actions to
provide alternative filtration
Cryptosporidium removal credit for
IESWTR or LTlESWTR compliance.
In the case of systems that use GWUDI
sources without additional filtration and
that meet all the criteria for avoiding
filtration in 40 CFR 141.71, samples
must be collected from the ground water
(e.g., the well). Further, such systems
must comply with the requirements of
the LT2ESWTR that apply to unfiltered
systems, as described in section IV.B.
b. How was this proposal developed?
This section describes the bank
filtration treatment process, provides
more detail on the aquifer types and
ground water collection devices that are
eligible for bank filtration credit, and
describes the data supporting the
proposed requirements.
Bank filtration is a water treatment
process that makes use of surface water
that has naturally infiltrated into ground
water via the river bed or bank(s) and
is recovered via a pumping well.
Stream-bed infiltration is typically
enhanced by the pumping action of
near-stream wells (e.g., water supply,
irrigation). Bank filtrate is water drawn
into a pumping well from a nearby
surface water source which has traveled
through the subsurface, either vertically,
horizontally or both, mixing to some
degree with other ground water.
Through bank filtration, microorganisms
and other particles are removed by
contact with the aquifer materials.
The bank filtration removal process
performs most efficiently when the
aquifer is comprised of granular
materials with open pore-space for
water flow around the grains. In these
granular porous aquifers, the flow path
is meandering, thereby providing ample
opportunity for the organism to come
into contact with and attach to a grain
surface. Although detachment can
occur, it typically occurs at a very slow
rate so that organisms remain attached
to a grain for long periods. When ground
water travel times from .source water to
well are long or when little or no
detachment occurs, most organisms will
become inactivated before they can
enter a well. Thus, bank filtration relies
on removal, but also, in some cases, on
inactivation to protect wells from
pathogen contamination.
Only Wells Located in Unconsolidated,
Predominantly Sandy Aquifers Are
Eligible
Only granular aquifers are eligible for
bank filtration credit. Granular aquifers
are those comprised of sand, clay, silt,
rock fragments, pebbles or larger
particles and minor cement. The aquifer
material is required to be
unconsolidated, with subsurface
samples friable upon touch.
Uncemented granular aquifers are
typically formed by alluvial or glacial
processes. Such aquifers are usually
identified on a detailed geologic map
(e.g., labeled as Quaternary alluvium).
Under today's proposal, a system
seeking Cryptosporidium removal credit
must characterize the aquifer at the well
site to determine aquifer properties. At
a minimum, the aquifer characterization
must include the collection of relatively
undisturbed, continuous, core samples
from the surface to a depth equal to the
bottom of the well screen. The proposed
site must have substantial core recovery
during drilling operations; specifically,
the recovered core length must be at
least 90% of the total projected depth to
the well screen.
Samples of the recovered core must be
submitted to a laboratory for sieve
analysis to determine grain size
distribution over the entire recovered
core length. Each sieve sample must be
acquired at regular intervals over the
length of the recovered core, with one
sample representing a composite of each
two feet of recovered core. A two-foot
sampling interval reflects the necessity
to sample the core frequently without
imposing an undue burden. Because it
is anticipated that wells will range from
50 to 100 foot in depth, a two-foot
sampling interval will result in about 25
to 50 samples for analysis. Each
sampled interval must be examined to
determine if more than ten percent of
the grains in that interval are less than
1.0 mm in diameter (#18 sieve size). In
the U.S. Department of Agriculture soil
classification system, the #18 sieve
separates very coarse sands from coarse
sands. The length of core (based on the
samples from two-foot intervals) with
more than ten percent of the grains less
than 1.0 mm in diameter must be
summed to determine the overall core
length with sufficient fine-grained
material so as to provide adequate
removal. An aquifer is eligible for
removal credit if at least 90% of the
sampled core length contains sufficient
fine-grained material as defined in this
section.
Cryptosporidium oocysts have a
natural affinity for attaching to fine-
grained material. A study of oocyst
removal in sand columns shows greater
oocyst removal in finer-grained sands
than in coarser-grained sands (Harter et
al. 2000), The core sampling procedure
described in this section is designed to
measure the proportion of fine-grained
sands (grains less than 1.0 mm in
diameter) so as to ensure that a potential
bank filtration site is capable of
retarding transport (or removing)
oocysts during ground water flow from
the source surface water to the water
supply well. The value of 1.0 mm for
the bounding size of the sand grains was
determined based on calculations
performed by Harter using data from
Harter et al. (2000). Harter showed that,
for ground water velocities typical of a
bank filtration site (1.5 to 15 m/day), a
typical bank filtration site composed of
grains with a diameter of 1.0 mm would
achieve at least 1.0 log removal over a
50 foot transport distance. Larger-sized
grains would achieve less removal, all
other factors being equal.
Alluvial and glacial aquifers are
complex mixtures of sand, gravel and
other sized particles. Particles of similar
size are often grouped together in the
subsurface, due to sorting by flowing
water that carries and then deposits the
particles. Where there exists significant
thickness of coarse-grained particles,
such as gravels, with few finer
materials, there is limited opportunity
for oocyst removal. When the total
gravel thickness, as measured in a core,
exceeds 10%, it is more likely (based on
analysis of ground water flow within
mixtures containing differing-sized
grains) that the gravel-rich intervals are
interconnected. Interconnected gravel
can form a continuous, preferential flow
path from the source surface water to
the water supply well. Where such
preferential flow paths exist, a
preponderance of the total ground water
flow occurs within the preferential flow
path, ground water velocity is higher,
and natural filtration is minimal. A
proposed bank filtration site is
acceptable if at least 90% of the core
length contains grains with sufficient
fine-grained material (diameter less than
1.0 mm); that is, it is acceptable if the
core contains less than 10% gravel-rich
intervals.
Aquifer materials with significant
fracturing are capable of transmitting
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47693
ground water at high velocity in a direct
flow path with little time or opportunity
for die-off or removal of microbial
pathogens. Consolidated aquifers,
fractured bedrock, and karst limestone
are aquifers in which surface water may
enter into a pumping well by flow along
a fracture, a solution-enhanced fracture
conduit, or other preferential pathway.
Microbial pathogens found in surface
water are more likely to be transported
to a well via these direct or preferential
pathways. Cryptosporidium outbreaks
have been associated with consolidated
aquifers, such as a fractured chalk
aquifer (Willocks et a!. 1998) or a karst
limestone (solution-enhanced fractured)
aquifer (Bergmire-Sweat et al. 1999).
These outbreaks show that the oocyst
removal performance of consolidated
aquifers is undermined by preferential
water flow and oocyst transport through
rock fractures or through rock
dissolution zones. Wells located in
these aquifers are not eligible for bank
filtration credit because the flow paths
are direct and the average ground water
velocity is high, so that little
inactivation or removal would be
expected. Therefore, only
unconsolidated aquifer are eligible for
bank filtration oocyst removal credit.
A number of devices are used for the
collection of ground water including
horizontal and vertical wells, spring
boxes, and infiltration galleries. Among
these, only horizontal and vertical wells
are eligible for log removal credit. The
following discussion presents
characteristics of ground water
collection devices and the basis for this
proposed requirement.
Horizontal wells are designed to
capture large volumes of surface water
recharge. They typically are constructed
by the excavation of a central vertical
caisson with laterals that extend
horizontally from the caisson bottom in
all directions or only under the
riverbed. Horizontal wells are usually
shallower than vertical wells because of
the construction expense. Ground water
flow to a horizontal well that extends
under surface water is predominantly
downward. In contrast, ground water
flow to a vertical well adjacent to
surface water may be predominantly in
the horizontal direction. Surface water
may have a short ground water flow
path to a horizontal well if the well
extends out beyond the bank.
Hancock et al. (1998) analyzed
samples from eleven horizontal wells
and found Cryptosporidium, Giardia or
both in samples from five of those wells.
These data suggest that some horizontal
wells may not be capable of achieving
effective Cryptosporidium removal by
bank filtration. Insufficient data are
currently available to suggest that
horizontal well distances from surface
water should be greater than distances
established for vertical wells. Two
ongoing studies in Wyoming (Clancy
Environmental Consultants 2002) and
Nebraska (Rice 2002) are collecting data
at horizontal well sites.
A spring box is located at the ground
surface and is designed to contain
spring outflow and protect it from
surface contamination until the water is
utilized. Spring boxes are typically
located where natural processes have
enhanced and focused ground water
discharge into a smaller area and at a
faster volumetric flow rate than
elsewhere (i.e., a spring). Often,
localized fracturing or solution
enhanced channels are the cause of the
focused discharge to the spring orifice.
Fractures and solution channels have
significant potential to transport
microbial contaminants so that natural
filtration may be poor. Thus, spring
boxes are not proposed to be eligible for
bank filtration credit.
Cryptosporidium monitoring results
(Hancock et al. 1998) and outbreaks are
used to evaluate ground water collection
devices. Hancock et al. sampled thirty
five springs for Cryptosporidium oocysts
and Giardia cysts. Most springs were
used as drinking water sources and
sampling was conducted to determine if
the spring should be considered as a
GWUDI source. Cryptosporidium
oocysts were found in seven springs;
Giardia cysts were found in five springs;
and either oocysts or cysts were found
in nine springs (26%). A waterborne
cryptosporidiosis outbreak in Medford,
Oregon (Craun et al. 1998) is associated
with a spring water supply collection
device. Also, a more recent, smaller
outbreak of giardiasis in an Oregon
campground is associated with a PWS
using a spring. The high percentage of
springs contaminated with pathogenic
protozoan, the association with recent
outbreaks, and an apparent lack of bank
filtration capability indicate that spring
boxes must not be eligible for bank
filtration credit.
An infiltration gallery (or filter crib) is
typically a slotted pipe installed
horizontally into a trench and backfilled
with granular material. The gallery is
designed to collect water infiltrating
from the surface or to intercept ground
water flowing naturally toward the
surface water (Symons et al. 2000). In
some treatment plants, surface, water is
transported to a point above an
infiltration gallery and then allowed to
infiltrate. The infiltration rate may be
manipulated by varying the properties
of the backfill or the nature of the soil-
water interface. Because the filtration
properties of the material overlying an
infiltration gallery may be designed or
purposefully altered to optimize oocyst
removal or for other reasons, this
engineered system is not bank filtration,
which relies solely on the natural
properties of the system.
A 1992 cryptosporidiosis outbreak in
Talent, Oregon was associated with poor
performance of an infiltration gallery
underneath Bear Creek (Leland et al
1993). In this case, the ground water-
surface water interface and the
engineered materials beneath did not
sufficiently reduce the high oocyst
concentration present in the source
water. The association of an infiltration
gallery with an outbreak, the design that
relies on engineered materials rather
than the filtration properties of natural
filtration media, and the shallow depth
of constructed infiltration galleries, such
that they typically are not located
greater than 25 feet from the surface and
surface water recharge, all indicate that
infiltration galleries must not be eligible
for bank filtration credit.
EPA notes that under the
demonstration of performance credit
described in section IV.C.17, States may
consider awarding Cryptosporidium
removal credit to infiltration galleries
where the State determines, based on
site-specific testing with a State-
approved protocol, that such credit is
appropriate (i.e., that the process
reliably achieves a specified level of
Cryptosporidium removal on a
continuing basis).
Wells Located 25 Feet From the Surface
Water Source Are Eligible for 0.5 Log
Credit; Wells Located 50 Feet From the
Surface Water Source Are Eligible for
1.0 Log Credit
A vertical or horizontal well located
adjacent to a surface water body is
eligible for bank filtration credit if there
is sufficient ground water flow path
length to effectively remove oocysts. For
vertical wells, the wellhead must be
located at least 25 horizontal feet from
the surface water body for 0.5 log
Cryptosporidium removal credit and at
least 50 horizontal feet from the surface
water body for 1.0 log Cryptosporidium
removal credit. For horizontal wells, the
laterals must be located at least 25 feet
distant from the normal-flow surface
water riverbed for 0.5 log
Cryptosporidium removal credit and at
least 50 feet distant from the normal-
flow surface water riverbed for 1.0 log
Cryptosporidium removal credit.
The ground water flow path to a
vertical well is the measured distance
from the edge of the surface water body,
under high flow conditions (determined
by the mapped extent of the 100 year
-------
floodplain elevation boundary or
floodway, as defined in Federal
Emergency Management Agency
(FEMA) flood hazard maps), to the
wellhead. The ground water flow path
to a horizontal well is the measured
distance from the bed of the river under
normal flow conditions to the closest
horizontal well lateral.
The floodway is defined by FEMA as
the area of the flood plain where the
water is likely to be deepest and fastest.
The floodway is shown on FEMA digital
maps (known as Q3 flood data maps),
which are available for 11,990
communities representing 1,293
counties in the United States. Systems
may identify the distance to surface
water using either the 100 year return
period flood elevation boundary or by
determining the floodway boundary
using methods similar to those used in
preparing FEMA flood hazard maps.
The 100 year return period flood
elevation boundary is expected to be
wider than the floodway but that
difference may vary depending on local
conditions. Approximately 19,200
communities in the United States have
flood hazard maps that show the 100
year return period flood elevation
boundary. If local FEMA floodway
hazard maps are unavailable or do not
show the 100 year flood elevation
boundary, then the utility must
determine either the floodway or 100
year flood elevation boundary.
The separation distance proposed tor
Cryptosporidium removal credit is
based, in part, on measured data for the
removal of oocyst surrogate biota in full-
scale field studies. A variety of surrogate
and indicator organisms were analyzed
in each study evaluated for today's
proposal. However, only two non-
pathogenic organisms, anaerobic
clostridia spores and aerobic
endospores, are resistant to inactivation
in the subsurface, approximately similar
in size and shape to oocysts, and
sufficiently ubiquitous in both surface
water and ground water so that log
removal can be calculated during
passage across the surface water—
ground water interface and during
transport within the aquifer.
Anaerobic spores are typically
estimated at about 0.3-0.4 urn in
diameter as compared with 4-6 um for
oocysts. Aerobic spores, such as
endospores of the bacterium Bacillus
subtilis, are slightly larger than
anaerobic spores, typically 0.5 x 1.0 x
2.0 Mm in diameter (Rice et al. 1996).
Experiments conducted by injecting
Bacillus subtilis spores into a gravel
aquifer show that they can be very
mobile in the subsurface environment
(Pang et al. 1998). As presented in the
following discussion, available data
indicate similar removal of both aerobic
and anaerobic spores, either during
passage across the surface water-
ground water interface or during ground
water flow. These data suggest that
anaerobic spores, like aerobic spores,
may be suitable surrogate measures of
Cryptosporidium removal by bank
filtration.
Available data establish that during
bank filtration, significant removal of
anaerobic and aerobic spores can occur
during passage across the surface water-
ground water interface, with lesser
removal occurring during ground water
transport within the aquifer away from
that interface. The ground water-surface
water interface is typically comprised of
finer grained material that lines the
bottom of the riverbed. Typically, the
thickness of the interface is small,
typically a few inches to a foot. The
proposed design criteria of 25 and 50
feet for 0.5 and 1.0 log Cryptosporidium
removal credit, respectively, are based
on EPA's analysis of pathogen and
surrogate monitoring data from bank
filtration sites. Most of these data are
from studies of aquifers developed in
Dutch North Sea margin sand dune
fields and, therefore, represent optimal
removal conditions consistent with a
homogenous, well sorted (by wind),
uniform sand filter.
Medema et al. (2000) measured 3.3
log removal of anaerobic spores during
transport over a 13 m distance from the
Meuse River into adjacent ground water.
Arora et al. (2000) measured greater
than 2.0 log removal of anaerobic spores
during transport from the Wabash River
to a horizontal collector well. Havelaar
etal. (1995) measured 3.1 log removal
of anaerobic spores during transport
over a 30 m distance from the Rhine
River to a well and 3.6 log removal over
a 25 m distance from the Meuse River
to a well. Schijven et al. (1998)
measured 1.9 log removal of anaerobic
spores over a 2 m distance from a canal
to a monitoring well. Using aerobic
spores, Wang et aL (2001) measured 1.8
log removal over a 2 foot distance from
the Ohio river to a monitoring well
beneath the river.
During transport solely within
shallow ground water (i.e,, not
including removal across the surface
water-ground water interface), Medema
et al. (2000) measured approximately
0.6 log removal of anaerobic spores over
a distance of 39 feet. Using aerobic
spores, Weng et al. (2001) measured 1.0
log removal of aerobic spores over a 48
foot distance from a monitoring well
beneath a river to a horizontal well
lateral.
At distances relatively far from an
injection well in a deep, anaerobic
aquifer, thereby minimizing the effects
of injection, Schijven et al measured
negligible removal of anaerobic spores
over a 30 m distance. However, few
bank filtration systems occur in deeper,
anaerobic ground water so these data
may not apply to a typical bank
filtration system in the United States.
These data demonstrate that during
normal and low surface water
elevations, the surface water-ground
water interface performs effectively to
remove microbial contamination.
However, there will typically be high
water elevation periods during the year,
especially on uncontrolled rivers, that
alter the nature and performance of the
interface due to flood scour, typically
for short periods. During these periods,
lower removals would be expected to
occur.
Averaging Cryptosporidium oocyst
removal over the period of a year
requires consideration of both high and
low removal periods. During most of the
year, high log removal rates would be
expected to predominate (e.g., 3.3 log
removal over 42 feet) due to the removal
achieved during passage across the
surface water-ground water interface.
During short periods of flooding,
substantially lower removal rates may
occur (e.g., 0.5 log removal over 39 feet)
due to scouring of the riverbed and
removal of the protective, fine-grained
material. By considering all time
intervals with differing removal rates
over the period of a year, EPA is
proposing that 0.5 log removal over 25
feet (8 m) and 1.0 log removal over 50
feet (16 m) are reasonable estimates of
the average performance of a bank
filtration system over a year. This
proposal is generally supported by
colloidal filtration theory modeling
results using data characteristic of the
aquifers in Louisville and Cincinnati
and column studies of oocyst transport
in sand (Harter et al 2000).
Wells must be continuously monitored
for turbidity
Under the Surface Water Treatment
Rule (40 CFR 141.73(b)(l)) the turbidity
level of slow sand filtered water must be
1 NTU or less in 95% of the
measurements taken each month.
Turbidity sampling is required once
every four hours, but may be reduced to
once per day under certain conditions.
Although slow sand filtration is not
bank filtration, similar pathogen
removal mechanisms are expected to
occur in both processes. Just as turbidity
monitoring is used to provide assurance
that the removal credit assigned to a
slow sand filter is being realized, EPA
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47695
is proposing continuous turbidity
monitoring for all bank filtration wells
tbat receive credit.
If monthly average turbidity levels
(based on daily maximum values in the
well) exceed 1 NTU, the system is
required to report to the State and
present an assessment of whether
microbial removal has been
compromised. If the State determines
that microbial removal has been
compromised, the system must not
receive credit for bank filtration until
the problem has been remediated. The
turbidity performance requirement for
bank filtration is less strict than that for
slow sand filtration because, unlike
slow sand filtration, bank filtration is a
pre-treatment technique followed by
conventional or direct filtration.
BILLING CODE 6560-50-P
Table IV-13.- Summary Table Showing All Requirements for Bank Filtration Pre-
treatment Log Removal Credit
Eligible for
Bank
filtration
Credit?
Some
GWUDI Sites
Eligible
Some Water
Collection
Devices
Eligible
Yes, eligible for bank
filtration credit (with
continuous turbidity
monitoring*) and
State approval
• Unconsolidated,
young, sandy**,
granular aquifer
• Vertical wells
located greater than
25 feet (0.5 log
credit) or 50 feet
(1.0 log credit) from
surface water
• Horizontal wells
with laterals that are
no closer than 25
feet (0.5 log credit)
or 50 feet (1.0 log
credit) from the river
channel under
normal flow
conditions
No, not eligible for
bank filtration credit
• Located in a
hydrogeologic setting
consisting of
consolidated material
* Spring boxes
• Infiltration galleries
• Horizontal wells
with laterals that
extend within 25 feet
of the river channel
under normal flow
conditions
• Vertical wells
located fewer than 25
feet from surface
water (measured
from the mapped
FEMA floodway
boundary)
"Average monthly turbidity values (based on daily maximum values) exceeding 1 NTU trigger an investigation by the
system and consultation with the primacy agency
**Based on laboratory analysis of continuous core samples collected at the site; At least 90% of the recovered core
length must contain intervals in which more than 10% of the grains are less than 1.0 mm in diameter.
BILLING CODE 6560-50-C
In summary, EPA believes that the
measured full-scale field data from
operating bank filtration systems, the
turbidity monitoring provision, and the
design criteria for aquifer material,
collection device type, and setback
distance, together provide assurance
that the presumptive log removal credit
will be achieved by bank filtration
systems that conform to the
requirements in today's proposal.
c. Request for comment. The Agency
requests comment on the following
issues concerning bank filtration:
• The performance of bank filtration
in removing Cryptosporidium or
surrogates to date at sites currently
using this technology (e.g. sites with
horizontal wells).
• The use of other methods (e.g.,
geophysical methods such as ground
penetrating radar) to complement or
supplant core drilling to determine site
suitability for bank filtration credit.
• The number of GWUDI systems in
each State (i.e., the number of systems
having at least one GWUDI source)
where bank filtration has been utilized
as the primary filtration barrier (e.g., no
other physical removal technologies
follow); also, the method that was used
by the State to determine that each
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47696
Federal Register/Vol. 68, No. 154/Monday. August 11, 2003/Proposed Rules
system was achieving 2 log removal of
Cryptosporidium.
• For GWUDI systems where natural
or alternative filtration (e.g. bank
filtration or artificial recharge) is used in
combination with a subsequent
filtration barrier (e.g., bag or cartridge
filters) to meet the 2 log
Cryptosporidium removal requirement
of the IESWTR or LT1ESWTR, how
much Cryptosporidium removal credit
has the State awarded (or is the State
willing to grant if the bags/cartridges
were found to be achieving < 2.0 logs)
for the natural or alternative filtration
process and how did the State
determine this value?
• The proposed Cryptosporidium
removal credit and associated design
criteria, including any additional
information related to this topic.
• Suitable separation distance(s) to be
required between vertical or horizontal
wells and adjacent surface water.
• Testing protocols and procedures
for making site specific determinations
of the appropriate level of
Cryptosporidium removal credit to
award to bank filtration processes.
• Information on the data and
methods suitable for predicting
Cryptosporidium removal based on the
available data from surrogate and
indicator measurements in water
collection devices.
• The applicability of turbidity
monitoring or other process monitoring
procedures to indicate the ongoing
performance of bank filtration
processes.
7. Lime Softening
a. What is EPA proposing today? Lime
softening is a drinking water treatment
process that uses precipitation with
lime and other chemicals to reduce
hardness and enhance clarification prior
to filtration. Lime softening can be
categorized into two general types: (1)
Single-stage softening, which is used to
remove calcium hardness and (2) two-
stage softening, which is used to remove
magnesium hardness and greater levels
of calcium hardness. A single-stage
softening plant includes a primary
clarifier and filtration components. A
two-stage softening plant also includes
a secondary clarifier located between
the primary clarifier and filter. In some
two-stage softening plants, a portion of
the flow bypasses the first clarifier.
EPA has determined that lime
softening plants in compliance with
IESWTR or LT1ESWTR achieve a level
of Cryptosporidium removal equivalent
to conventional treatment plants (i.e.,
average of 3 log). Consequently, lime
softening plants that are placed in Bins
2—4 as a result of Cryptosporidium
monitoring incur the same additional
treatment requirements as conventional
plants. However, EPA is proposing that
two-stage softening plants be eligible for
an additional 0.5 log Cryptosporidium
treatment credit. To receive the 0.5 log
credit, the plant must have a second
clarification stage between the primary
clarifier and filter that is operated
continuously, and both clarification
stages must treat 100% of the plant
flow. In addition, a coagulant must be
present in both clarifiers (may include
metal salts, polymers, lime, or
magnesium precipitation).
b. How was this proposal developed?
The lime softening process is used to
remove hardness, primarily calcium and
magnesium, through chemical
precipitation followed by sedimentation
and filtration. The addition of lime
increases pH, causing the metal ions to
precipitate. Other contaminants can
coalesce with the precipitates and be
removed in the subsequent settling and
filtration processes. While elevated pH
has been shown to inactivate some
microorganisms like viruses (Battigelli
and Sobsey, 1993, Logsdon etal 1994),
current research indicates that
Cryptosporidium and Giardia are not
inactivated by high pH (Logsdon et al
1994, Li et al. 2001). A two-stage lime
softening plant has the potential for
additional Cryptosporidium removal
because of the additional sedimentation
process.
Limited data are available on the
removal of Cryptosporidium by the lime
softening treatment process. EPA has
evaluated data from a study by Logsdon
et al (1994), which investigated
removal of Giardia and Cryptosporidium
in full scale lime softening plants. In
addition, the Agency has considered
data provided by utilities on the
removal of aerobic spores in softening
plants. These data are summarized in
the following paragraphs.
Logsdon et al. (1994) measured levels
of Cryptosporidium and Giardia in the
raw, settled, and filtered water of 13
surface water plants using lime
softening. Cryptosporidium was
detected in the raw water at 5 utilities:
one single-stage plant and four two-
stage plants. Using measured oocyst
levels, Cryptosporidium removal by
sedimentation was 1.0 log in the single-
stage plant and 1.1 to 2.3 log in the two-
stage plants. Cryptosporidinm was
found in two filtered water samples of
the single stage plant, leading to
calculated removals from raw to filtered
water of 0.6 and 2.2 log. None of the
two-stage plants had Cryptosporidium
detected in the filtered water. Based on
detection limits, calculated
Cryptosporidium removals from raw to
filtered water in the two-stage plants
ranged from >2.67 to >3.85 log.
Giardia removal across sedimentation
was >0.9 log for a single-stage plant and
ranged from 0.8 to 3.2 log for two-stage
plants, based on measured cyst levels.
Removal of Giardia from raw water
through filtration was calculated using
detection limits as >1.5 log in a single-
stage plant and ranged from >0.9 to >3.3
log in two-stage plants.
While results from the Logsdon et al
study are constrained by sample number
and method detection limits, they
suggest that two-stage softening plants
may achieve greater removal of
Cryptosporidium than single-stage
plants. The authors concluded that two
stages of sedimentation, each preceded
by effective flocculation of particulate
matter, may increase removal of
protozoa. Additionally, the authors
stated that consistent achievement of
flocculation that results in effective
settling in each sedimentation basin is
the key factor in this treatment process.
Removal of Aerobic Spores by Softening
Plants
Additional information on the
microbial removal efficiency of the lime
softening process comes.from data
provided by softening plants on removal
of aerobic spores. While few treatment
plants have sufficient concentrations of
oocysts to directly calculate a
Cryptosporidium removal efficiency,
some plants have high concentrations of
aerobic spores in the raw water. Spores
may serve as an indicator of
Cryptosporidium removal by
sedimentation and filtration (Dugan et
al 2001).
The following two-stage softening
plants provided data on removal of
aerobic spores: St. Louis, MO, Kansas
City, MO, and Columbus, OH (2 plants).
Cryptosporidium data were also
collected at these utilities, but it was not
possible to calculate oocyst removal due
to low raw water detection rates. Data
on removal of aerobic spores by these
softening plants is summarized in Table
IV-14.
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Federal Register/Vol. 68, No. 154/Monday, August 11, 2003/Proposed Rules 47697
TABLE IV-14.—SUMMARY OF AEROBIC SPORE REMOVAL DATA FROM SOFTENING PLANTS
Plant
Columbus Plant 2
Mean log removal of aerobic spores
Primary clari-
fier
1.7
2.4
1.2
1.3
Secondary
clarifier
1.1
0
1.6
2.4
Across plant*
3.8
3.4
3.1
4.2
'Excludes removal in pre-sedimentation basins; calculated spore removal may underestimate actual removal due to filter effluent levels below
quantitation limits.
The City of St. Louis Water Division
operates a two-stage lime softening
process preceded by presedimentation.
Ferric sulfate and polymer coagulants
are added at various points in the
process. St. Louis collected Bacillus
subtilis spore samples between June
1998 and September 2000. During this
time period, the mean spore
concentration entering the softening
process (i.e., after presedimentation}
was 8,132 cfu/100 mL. The log removal
values shown in Table IV-14 are based
on average spore concentrations
following primary clarification,
secondary clarification, and filtration.
However, spore levels in some filtered
water samples were below the method
detection limit, so that the true mean
spore removal across the plant may have
been higher than indicated by the
calculated value.
The Kansas City Water Services
Department plant includes two-stage
lime softening with pre-sedimentation
and sludge recycle. Bacillus subtilis
spore data were collected from this
plant during January through November
2000. The mean spore concentration
entering the lime softening process
(after presedimentation) was 5,965 cfu/
100 mL. Mean spore levels following
primary clarification, secondary
clarification, and filtration were 21.1,
25.7, and 2.6 cfu/100 mL, respectively.
Corresponding log removal values are
shown in Table IV-14. Note that the
average spore concentration in the
effluent of the secondary clarifier was
essentially equivalent to the effluent of
the primary clarifier, indicating that
little removal occurred in the secondary
clarifier. This result may have been due
to the high removal achieved in the
primary clarifier and, consequently, the
relatively low concentration of spores
entering the second clarifier. As with
the St. Louis plant, many of the filtered
water observations were below method
detection limits, so actual log removal
across the plant may have been higher
than the calculated value.
The City of Columbus operates two
lime softening plants, each of which has
two clarification stages. Coagulant is
added prior to the first clarification
stage but lime is not added until the
second clarifier (i.e., first clarifier is not
a softening stage). Between 1997 and
2000, samples for total aerobic spores
were collected approximately monthly
at each plant from raw water, following
each clarification basin, and after
filtration. Mean spore concentrations in
the raw water sources for the two plants
were 10,619 cfu/100 mL (Plant 1) and
22,595 cfu/100 mL (Plant 2). Mean log
removals occurring in the two
clarification stages and across the plant
are shown for each plant in Table IV-
14.
These data indicate that two-stage
softening plants can remove high levels
of Cryptosporidium, and, in particular,
that a second clarification stage can
achieve 0.5 log or greater removal. Three
of the four plants that provided data on
removal of aerobic spores achieved
greater than 1 log reduction in the
second clarifier. Kansas City, the one
plant which achieved little removal in
the second clarifier, achieved a mean
2.4 log removal in the primary clarifier.
This was approximately \ log more
reduction than achieved in the primary
clarifiers of the other three plants, so
that the spore concentration entering the
second clarifier in Kansas City may have
been too low to serve as an indicator of
removal efficiency. Consequently, EPA
has concluded that these data support
an additional Cryptosporidium
treatment credit of 0.5 log for a two-
stage softening plant.
EPA is proposing as a condition of the
0.5 log additional credit that a
coagulant, which could include excess
lime and soda ash or precipitation of
magnesium hydroxide, be present in
both clarifiers. This requirement is
necessary to ensure that significant
particulate removal occurs in both
clarification stages. Logsdon et al.
(1994) identified effective flocculation
as being a key factor for removal of
protozoa in softening plants. Among the
softening plants that provided data on
aerobic spore removal, St. Louis added
ferric and polymer coagulants at
different points in the process, and the
two Columbus plants added lime to the
second clarifier. Consequently, a
requirement that plants add a coagulant,
which may be lime, in the secondary
clarifier is consistent with the data used
to support the 0.5 log additional credit.
The Science Advisory Board (SAB)
reviewed the proposed Cryptosporidium
treatment credit for lime softening and
supporting information, as presented in
the November 2001 pre-proposal draft of
the LT2ESWTR (USEPA 2001g). In
written comments from a December
2001 meeting of the Drinking Water
Committee, the SAB panel concluded
that both single- and two-stage softening
generally outperform conventional
treatment due to the heavy precipitation
that occurs. Further, the panel found
that 0.5 log of additional
Cryptosporidium removal is an average
value for a two-stage lime softening
plant. However, the SAB stated that the
additional credit for two-stage softening
should be given only if all the water
passes through both stages. Today's
proposal is consistent with these
recommendations by the SAB.
EPA notes that by including a
presumptive credit for softening plants,
today's proposal differs from the Stage
2 M-DBP Agreement in Principle, which
recommends up to 1 log additional
Cryptosporidium treatment credit for
softening plants based on demonstration
of performance, but no additional
presumptive credit.
c. Request for comment. EPA requests
comment on the proposed criteria for
awarding credit to lime softening plants.
EPA would particularly appreciate
comment on the following issues:
• Whether the information and
analyses presented in this proposal
supports an additional 0.5 log credit for
two-stage softening, and the associated
criteria necessary for credit.
• Additional information that either
support or suggest modifications to the
proposed criteria and credit.
8. Combined Filter Performance
a. What is EPA proposing today? This
toolbox component will grant additional
credit towards Cryptosporidium
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47698 Federal Register/Vol. 68. No. 154/Monday, August 11. 2003/Proposed Rules
treatment requirements to certain plants
that maintain finished water turbidity at
levels significantly lower than currently
required. EPA is proposing to award an
additional 0.5 log Cryptosporidium
treatment credit to conventional and
direct filtration plants that demonstrate
a turbidity level in the combined filter
effluent (CFE) less than or equal to 0.15
NTU in at least 95 percent of the
measurements taken each month.
Compliance with this criterion must be
based on measurements of the CFE
every four hours (or more frequently)
that the system serves water to the
public. This credit is not available to
membrane, bag/cartridge, slow sand, or
DE plants, due to the lack of
documented correlation between
effluent turbidity and Cryptosporidium
removal in these processes.
b. How was this proposal developed?
Turbidity is an optical property
measured from the amount of light
scattered by suspended particles in a
solution. It is a method defined
parameter that can detect the presence
of a wide variety of particles in water
(e.g., clay, silt, mineral particles, organic
and inorganic matter, and
microorganisms), but it cannot provide
specific information on particle type,
number, or size. Turbidity is used as an
indicator of raw and finished water
quality and treatment performance.
Turbidity spikes in filtered water
indicate a potential for breakthrough of
pathogens.
Under the IESWTR and LT1ESWTR,
combined filter effluent turbidity in
conventional and direct filtration plants
must be less than or equal to 0.3 NTU
in 95% of samples taken each month
and must never exceed 1 NTU. These
plants are also required to conduct
continuous monitoring of turbidity for
each individual filter, and provide an
exceptions report to the State when
certain criteria for individual filter
effluent turbidity are exceeded
(described in 63 FR 69487, December
16, 1998) (USEPA 1998a).
The Stage 2 M-DBP Advisory
Committee recommended that systems
receive an additional 0.5 log
Cryptosporidium removal credit for
maintaining 95th percentile combined
filter effluent turbidity below 0.15 NTU,
which is one half of the current required
level of 0.3 NTU. In considering the
technical basis to support this
recommendation, EPA has reviewed
studies that evaluated the efficiency of
granular media filtration in removing
Cryptosporidium when operating at
different effluent turbidity levels.
For the IESWTR, EPA estimated that
plants would target filter effluent
turbidity in the range of 0.2 NTU in
order to ensure compliance with a
turbidity standard of 0.3 NTU.
Similarly, EPA has estimated that plants
relying on meeting a turbidity standard
of 0.15 NTU in 95% of samples will
consistently operate below 0.1 NTU in
order to ensure compliance.
Consequently, to assess the impact of
compliance with the lower finished
water turbidity standard, EPA compared
Cryptosporidium removal efficiency
when effluent turbidity is below 0.1
NTU with removal efficiency when
effluent turbidity is in the range of 0.1
to 0.2 NTU. Results from applicable
studies are summarized in Table IV-15
and are discussed in the following
paragraphs.
TABLE IV-15.—STUDIES OF Cryptosporidium REMOVAL AT DIFFERENT EFFLUENT TURBIDITY LEVELS
Microorganism
^ . •" —
Average of log
removals
4.39
3.55
4.23
3.22
4.09
3.58
3.76
2.56
Filtered effluent turbidity
<0 1 NTU
>0.1 and <0.2 NTU
<0.1 NTU
>0.1 and <0.2 NTU
<0 1 NTU
>0.1 and <0.2 NTU
<0.1 NTU
>0.1 and <0.2 NTU
Experiment design
Pilot-scale
Bench-scale
Researcher
Pataniaetal. {1995).
Emelkoetal. (1999).
Dugan et al. (2001).
Patania et al. (1995) conducted pilot-
scale studies at four locations to
evaluate the removal of seeded
Cryptosporidium and Giardia, turbidity,
and particles. Treatment processes,
coagulants, and coagulant doses differed
among the four locations. Samples of
filter effluent were taken at times of
stable operation and filter maturation.
Analysis of summary data from the
seeded runs at all locations shows that
average Cryptosporidium removal was
greater by more than 0.5 log when
effluent turbidity was less than 0.1
NTU, in comparison to removal with
effluent turbidity in the range 0.1 to 0.2
NTU (see Table IV-15).
Emelko et al. (1999) used a bench
scale dual media filter to study
Cryptosporidium removal during both
optimal and challenged operating
conditions. Water containing a
suspension of kaolinite (clay) was
spiked with oocysts, coagulated in-line
with alum, and filtered. Oocyst removal
was evaluated during stable operation
when effluent turbidity was below 0.1
NTU. Removal was also measured after
a hydraulic surge that caused process
upset, and with coagulant addition
terminated. These later two conditions
resulted in effluent turbidities greater
than 0.1 NTU and decreased removal of
Cryptosporidium. As shown in Table
IV-15, average removal of
Cryptosporidium during periods with
effluent turbidity below 0.1 NTU was
approximately 0,5 log greater than when
effluent turbidity was between 0.1 to 0.2
NTU.
Dugan etal (2001) evaluated
Cryptosporidium removal in a pilot
scale conventional treatment plant.
Sixteen filtration runs seeded with
Cryptosporidium were conducted at
different raw water turbidities and
coagulation conditions. Eleven of the
runs had an effluent turbidity below 0.1
NTU, and five runs had effluent
turbidity between 0.1 and 0.2 NTU. For
runs where the calculated
Cryptosporidium removal was
concentration limited (i.e., effluent
values were non-detect), the method
detection limit was used to calculate the
values shown in Table IV-15. Using this
conservative estimate, average
Cryptosporidium removal with effluent
turbidity below 0.1 NTU exceeded by
more than 1 log the average removal
observed with effluent turbidity
between 0.1 to 0.2 NTU.
In summary, these three studies all
support today's proposal in showing
that plants consistently operating below
0.1 NTU can achieve an additional 0.5
log or greater removal of
Cryptosporidium than when operating
between 0.1 and 0.2 NTU. Because EPA
expects plants relying on compliance
with a 0.15 NTU standard will
consistently operate below 0.1 NTU, the
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Federal Register/Vol. 68, No. 154/Monday, August 11, 2003/Proposed Rules
47699
Agency has determined it is appropriate
to propose an additional 0.5 log
treatment credit for plants meeting this
standard.
The SAB reviewed the proposed
additional 0.5 log Cryptosporidium
removal credit for systems maintaining
very low CFE turbidity, as presented in
the November 2001 pre-proposal draft of
the LT2ESWTR (USEPA 2001gj. The
SAB also reviewed a potential
additional 1.0 log Cryptosporidium
removal credit for systems achieving
very low individual filter effluent (IFE)
turbidity, which is addressed in section
IV.G.16 of today's proposal.
In written comments from a December
2001 meeting of the Drinking Water
Committee, the SAB panel stated that
additional credit for lower finished
water turbidity is consistent with what
is known in both pilot and full-scale
operational experiences for
Cryptosporidium removal. Recognizing
that IESWTR requirements for lowering
turbidity in the treated water will result
in lower concentrations of
Cryptosporidium, the panel affirmed
that even further lowering of turbidity
will result in further reductions in
Cryptosporidium in the filter effluent.
However, the SAB concluded that
limited data were presented to show the
exact removal that can be achieved, and
recommended that no additional credit
be given to plants that demonstrate CFE
turbidity of 0.15 NTU or less. The SAB
recommended that 0.5 log credit be
given to plants achieving IFE turbidity
in each filter less than 0.15 NTU in 95%
of samples each month.
In responding to this recommendation
from the SAB, EPA acknowledges the
difficulty in precisely quantifying
Cryptosporidium removal through
filtration based on effluent turbidity
levels. Nevertheless, EPA finds that
available data consistently show that
removal of Cryptosporidium is
increased by 0.5 log or greater when
filter effluent turbidity is reduced to
levels reflecting compliance with a 0.15
NTU standard, in comparison to
compliance with a 0.3 NTU standard.
Consequently, EPA has concluded that
it is appropriate to propose this 0.5 log
presumptive treatment credit for
systems achieving very low CFE
turbidity.
Measurement of Low Level Turbidity
Another important aspect of
proposing to award additional removal
credit for lower finished water turbidity
is the performance of turbidimeters in
measuring turbidity below 0.3 NTU. The
following paragraphs summarize results
from several studies that evaluated low
level measurement of turbidity by
different on-line and bench top
instruments. Note that because
compliance with the CFE turbidity limit
is based on 4-hour readings, either on-
line or bench top turbidimeters may be
used, EPA believes that results from
these studies indicate that currently
available turbidity monitoring
equipment is capable of reliably
assessing turbidity at levels below 0.1
NTU, provided instruments are well
calibrated and maintained.
The 1997 NODA for the IESWTR (67
FR 59502, Nov. 3, 1997) (USEPA 1997a)
discusses issues relating to the accuracy
and precision of low level turbidity
measurements. This document cites
studies (Hart et al 1992, Sethi et al
1997) suggesting that large tolerances in
instrument design criteria have led to
turbidimeters that provide different
turbidity readings for a given
suspension.
At the time of IESWTR NODA, EPA
had conducted performance evaluation
(PE) studies of turbidity samples above
0.3 NTU. A subsequent PE study
(USEPA 1998e), labeled WS041, was
carried out to address concern among
the Stage 1 M-DBP Federal Advisory
Committee regarding the ability to
reliably measure lower turbidity levels.
The study involved distribution of
different types of laboratory prepared
standard solutions with reported
turbidity values of 0.150 NTU or 0.160
NTU. The results of this study are
summarized in Table IV-16.
BILLING CODE 6560-50-P
Table IV-16.-- Performance Evaluation - WS041 Data for Low Level Turbidity
Analysis (USEPA 1998e)
Type of
Instrument
Bench Top
Portable or IR
Portable or IR
On-Line
Sample
Solution
Type
Polystyrene
Spheres
Polystyrene
Spheres
Formazin
Polystyrene
Spheres
"True"
Value
(NTU)
0.150
0.150
0.160
0.150
No. of
Results
Available
292
340
335
52
Mean*
(NTU)
0.203
0.200
0.176
0.228
Std. Dev*
(NTU)
0.0558
0.0439
0.0431
0.0773
95%
Prediction
Interval
(NTU)
0.093-0.313
0.113-0.286
0.091-0.261
0.072-0.385
'Calculated using biweight transformation
BILLING CODE 6S60-5
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47700
Federal Register/Vol. 68, No. 154/Monday, August 11. 2003/Proposed Rules
at lower than required effluent turbidity
levels).
Letterman et al, (2001) evaluated the
effect of turbidimeter design and
calibration methods on Inter-instrument
performance, comparing bench top to
on-line instruments and instruments
within each of those categories from
different manufacturers, The study used
treated water collected from the filter
effluent of water treatment plants.
Reported sample turbidity values ranged
from 0.05 to 1 NTU. Samples were
analyzed in a laboratory environment.
The results are consistent with those of
the WS041 study, specifically the
positive bias of on-line instruments.
However, Letterman et al. found
generally poor agreement among
different on-line instruments and
between bench-top and on-line
instruments. The authors also observed
that results were independent of the
calibration method, though certain
experiments suggested that analyst
experience may have some effect on
turbidity readings from bench-top
instruments.
Sadar (1999) conducted an infra-
instrument study of low level turbidity
measurements among instruments from
the same manufacturer. This study was
performed under well-controlled
laboratory conditions, //rtra-instrument
variation among different models and
between bench top and on-line
instruments occurred but at
significantly lower levels than the
Letterman et al. j'n tor-instrument study.
Newer instruments also tended to read
lower than older instruments, which the
author attributed to a reduction in stray
light and lower sensitivities in the
newer instruments. Sadar also found a
generally positive bias when comparing
on-line to bench-top and when
comparing all instruments to a prepared
standard.
The American Society for Testing and
Materials (ASTM) has issued standard
test methods for measurement of
turbidity below 5 NTU by on-line
(ASTM 2001) and static (ASTM 2003)
instrument modes. The methods specify
that the instrument should permit
detection of turbidity differences of 0.01
NTU or less in waters having turbidities
of less than 1.00 NTU (ASTM 2001) and
5.0 NTU (ASTM 2003), respectively.
/nter-laboratory study data included
with the method for a known turbidity
standard of 0.122 NTU show an analyst
relative deviation of 7.5% and a
laboratory relative deviation of 16%
(ASTM 2003).
In summary, the data collected in
these studies of turbidity measurement
indicate that currently available
monitoring equipment can reliably
measure turbidity at levels of 0.1 NTU
and lower. However, this requires
rigorous calibration and verification
procedures, as well as diligent
maintenance of turbidity monitoring
equipment (Burlingame 1998, Sadar
1999). Systems that pursue additional
treatment credit for lower finished water
turbidity must develop the procedures
necessary to ensure accurate and
reliable measurement of turbidity at
levels of 0.1 NTU and less. EPA
guidance for the microbial toolbox will
provide direction to water systems on
developing these procedures.
c. Request for comment. EPA invites
comment on the following issues
regarding the proposed
Cryptosporidium treatment credit for
combined filter performance:
• Do the studies cited here support
awarding 0.5 log credit for CFE < 0.15
NTU 95% of the time?
• Does currently available turbidity
monitoring technology accurately
distinguish differences between values
measured near 0.15 NTU?
9. Roughing Filter
a, What is EPA proposing todoy?The
Stage 2 M-DBP Agreement in Principle
recommends a 0.5 log presumptive
credit towards additional
Cryptosporidium treatment
requirements for roughing filters.
However, the Agreement further
specifies that EPA is to determine the
design and implementation criteria
under which the credit would be
awarded. Upon subsequent review of
available literature, EPA is unable to
identify design and implementation
conditions for roughing filters that
would provide reasonable assurance of
achieving a 0.5 log removal of oocysts.
Consequently, EPA is not proposing
presumptive credit for Cryptosporidium
removal by roughing filters. Today's
proposal does, though, include a 0.5 log
credit for a second granular media filter
following coagulation and primary
filtration (see section IV.C.13).
b. How was this proposal developed?
Roughing filtration is a technique used
primarily in developing countries to
remove solids from high turbidity
source waters prior to treatment with
slow sand filters. Typically, roughing
filters consist of a series of
sedimentation tanks filled with
progressively smaller diameter media in
the direction of flow. The media can be
gravel, plastic, crushed coconut, rice
husks, or a similar locally available
material. The flow direction in roughing
filters can be either horizontal or
vertical, and vertical roughing filters can
be either upflow or downflow. The
media in the tanks effectively reduce the
vertical settling distance of particles to
a distance of a few millimeters. As
sediment builds on the media, it
eventually sloughs off and begins to
accumulate in the lower section of the
filter, while simultaneously regenerating
the upper portions of the filter. The
filters require periodic cleaning to
remove the collected silt.
Review of the scientific and technical
literature pertaining to roughing filters
has identified no information on
removal of Cryptosporidium.
Information is available on removal of
suspended solids, turbidity, particles,
fecal coliforms and some algae, but none
of these has been demonstrated to be an
indicator of Cryptosporidium removal
by roughing filters. Moreover, roughing
filters are not preceded by a coagulation
step, and studies have found that some
potential surrogates, such as aerobic
spores, are not conservative indicators
of Cryptosporidium removal by
filtration when a coagulant is not
present (Yates et al. 1998, Dugan et al.
2001). Thus, it is unclear how to relate
results from studies of the removal of
other particles by roughing filters to
potential removal of Cryptosporidium.
In addition, some studies have
observed very poor removal of
Cryptosporidium by rapid sand filters
when a coagulant is not used (Patania et
al. 1995, Huck et al 2000). Based on
these findings, it is expected that there
would be situations where a roughing
filter would not achieve 0.5 log
Cryptosporidium removal. Because
available data are insufficient to
determine the conditions that would be
necessary for a roughing filter to achieve
0.5 log Cryptosporidium removal, EPA
is unable to propose this credit. The
following discussion describes four
studies that analyzed the effectiveness
of roughing filters for removing solids,
turbidity, particles, fecal coliforms, and
algae.
Wegelin et al. (1987) conducted pilot-
scale studies on the use of horizontal
roughing filters to reduce solids,
turbidity, and particles. Testing was
performed to determine the influence of
different design parameters on filter
performance. Data from the parameter
testing was used to establish an
empirical model to simulate filtrate
quality as a function of filter length and
time for a given filter configuration.
Using the mathematical model, the
researchers found that long filters (10 m)
at low filtration rates (0.5 m/h) were
capable of reducing high suspended
solids concentrations (1000 mg/L TSS)
down to less than 3 mg/L.
Further work by Wegelin (1988)
evaluated roughing filters as
pretreatment for slow sand filters for
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47701
waters with variable and seasonably
high suspended solids concentrations.
This study collected data on roughing
filters in Peru, Colombia, Sudan, and
Ghana. Table IV-17 summarizes data for
three of the roughing filters. These
filters were capable of reducing peak
turbidities by 80 to 90 percent. Further,
the Peruvian and Colombian filters
reduced fecal coliforms by 77 and 89
percent, respectively. The Sudanese
filter may have removed around 90
percent of the fecal coliforms, but
specific values were not given. Data
collected from roughing filters in Ghana
on algae removal indicate that the
Merismopedia (0.5 um) and Chlorophyta
(2-10 um), which are comparable in size
to Cryptosporidium oocysts, were
completely removed from the water in
mature filters, and that some removal of
Chlorophyta, but not Merismopedia,
occurred in filters after three days of
operation. However, the removal of
these organisms has not been correlated
with Cryptosporidium oocyst removal.
TABLE IV-17.—ROUGHING FILTER DATA FROM WEGELIN, 1988
Location
Azpita, Peru
0 30 m/h {0 98 ft/hr)
35 mVd
El Retire, Colombia
Upflow (multi-layer filter)
0.74 m/h (2.43 f/hr)
790 mVd
Blue Nile Health Project,
Sudan
Horizontal-flow.
0.3 m/h (0.98 ft/hr).
5 nP/d.
Turbidity (NTU)
Raw Water
Roughing Filter Effluent
50-200
15-40 .
10-150
5-15 ...
40-500
5-50
Fecal Coliforms (/100 mL)
700
160 ..
16,000
1,680
>300
<25
oiler (1993) details the mechanisms of
particle removal that occur in roughing
filters. The conclusions are similar to
those drawn by Wegelin et al. (1987).
Particle analysis reviewed by Boiler
indicates that after seven days of
operation, the four stage pilot filter
utilized by Wegelin et al (1987)
removed more than 98 percent of
particles sized 1.1 um, and greater than
99 percent of particles sized 3.6 um.
After 62 days, only 80 percent of
particles sized 1.1 um were removed,
while 90 percent of particles sized 3.6
um were removed. Boiler did not give
the solids loading on the tested filter,
and particle removal was not correlated
to Cryptosporidium oocyst removal.
Collins et al. (1994) investigated
solids and algae removal with pilot
scale vertical downflow roughing filters.
Gravel media size, filter depth, and flow
rate were varied to determine which
design variables had the greatest effect
on filter performance. Results indicated
that the most influential design
parameters for removing solids from
water, .in order of importance, were
filter length, gravel size, and hydraulic
flow rate. For algae removal, the most
influential design parameters were
hydraulic flow rate, filter length, and
gravel size. Solids removal was better in
filters that had been ripened with algae
for 5-7 days. However, extrapolation of
these results to Cryptosporidium
removal could not be made, .
c. Request for comment. The Agency
requests comment on the information
that has been presented about roughing
filters, and specifically the question of
whether and under what conditions
roughing filters should be awarded a 0.5
log credit for removal of
Cryptosporidium. EPA also requests
information on specific studies of
Cryptosporidium oocyst removal by
roughing filters, or from studies of the
removal of surrogate parameters that
have been shown to correlate with
oocyst removal in roughing filters.
10. Slow Sand Filtration
a. What is EPA proposing today? Slow
sand filtration is defined in 40 CFR
141.2 as a process involving passage of
raw water through a bed of sand at low
velocity (generally less than 0.4 m/h)
resulting in substantial particulate
removal by physical and biological
mechanisms. Today's proposal allows
systems using slow sand filtration as a
secondary filtration step following a
primary filtration process (e.g.,
conventional treatment) to receive an
additional 2.5 log Cryptosporidium
treatment credit. There must be no
disinfectant residual in the influent
water to the slow sand filtration process
to be eligible for credit.
Note that this proposed credit differs
from the credit proposed for slow sand
filtration as a primary filtration process.
EPA has concluded, based on treatment
studies described in section III.D, that
plants using well designed and well
operated slow sand filtration as a
primary filtration process can achieve
an average Cryptosporidium removal of
3 log (Schuler and Ghosh, 1991, Timms
et al. 1995, Hall et al. 1994).
Consequently, as described in section
IV.A, EPA is proposing that plants using
slow sand filtration as a primary
filtration process receive a 3 log credit
towards Cryptosporidium treatment
requirements associated with Bins 2-4
under the LT2ESWTR (i.e., credit
equivalent to a conventional treatment
plant).
The proposed 2.5 log credit for slow
sand filtration as part of the microbial
toolbox applies only when it is used as
a secondary filtration step, following a
primary filtration process like
conventional treatment.' While the
removal mechanisms that make slow
sand filtration effective as a primary
filtration process would also be
operative when used as a secondary
filtration step, EPA has little data on
this specific application. The Agency is
proposing 2.5 log credit for slow sand
filtration as a secondary filtration step,
in comparison to 3 log credit as a
primary filtration process, as a
conservative measure reflecting greater
uncertainty. In addition, the proposed
2.5 log credit for slow sand filtration as
part of the microbial toolbox is
consistent with the recommendation in
the Stage 2 M-DBP Agreement in
Principle.
b. How was this proposal developed?
The Stage 2 M-DBP Agreement in
Principle recommends that slow sand
filtration receive 2.5 log or greater
Cryptosporidium treatment credit when
used in addition to existing treatment
that achieves compliance with the
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IESWTR or LT1ESWTR. Slow sand
filtration is not typically used as a
secondary filtration step following
conventional treatment or other primary
filtration processes of similar efficacy.
However, EPA expects that slow sand
filtration would achieve significant
removal of Cryptosporidium in such a
treatment train.
While there is a significant body of
data demonstrating the effectiveness of
slow sand filtration for Cryptosporidium
removal as a primary filtration process,
as described in section III.D, EPA has
limited data on the effectiveness of slow
sand filtration when used as a
secondary filtration step. Hall et al
(1994) evaluated oocyst removal for a
pilot scale slow sand filter following a
primary filtration process identified as a
rapid gravity filter. The combined
treatment train of a primary filtration
process followed by slow sand filtration
achieved greater than 3 log
Cryptosporidium removal in three of
five experimental runs, while
approximately 2.5 log reduction was
observed in the other two runs. In
comparison, Hall et al. (1994) reported
slow sand filtration alone to achieve at
least a 3 log removal of oocysts in each
of four experimental runs when not
preceded by a primary filtration process.
The authors offered no explanation for
these results, but measured oocyst
removals may have been impacted by
limitations with the analytical method.
Removal of microbial pathogens in
slow sand filters is complex and is
believed to occur through a combination
of physical, chemical, and biological
mechanisms, both on the surface
(schmutzdecke) and in the interior of
the filter bed. It is unknown if the
higher quality of the water that would
be influent to a slow sand filter when
used as a secondary filtration step
would impact the efficiency of the filter
in removing Cryptosporidium. Based on
the limited data on the performance of
slow sand filtration as a secondary
filtration step, and in consideration of
the recommendation of the Advisory
Committee, EPA is proposing only a 2.5
log additional Cryptosporidium
treatment credit for this application,
c. Request for comment. The Agency
requests comment on whether the
available data are adequate to support
awarding a 2.5 log Cryptosporidium
removal credit for slow sand filtration
applied as a secondary filtration step,
along with any additional information
related to this application.
11. Membrane Filtration
a. What is EPA proposing today? EPA
is proposing criteria for awarding credit
to membrane filtration processes for
removal of Cryptosporidium. To receive
removal credit, the membrane filtration
process must: (1) Meet the basic
definition of a membrane filtration
process, (2) have removal efficiency
established through challenge testing
and verified by direct integrity testing,
and (3) undergo periodic direct integrity
testing and continuous indirect integrity
monitoring during use. The maximum
removal credit that a membrane
filtration process is eligible to receive is
equal to the lower value of either:
—The removal efficiency demonstrated
during challenge testing OR
—The maximum log removal value that
can be verified through the direct
integrity test (i.e., integrity test
sensitivity) used to monitor the
membrane filtration process.
By the criteria in today's proposal, a
membrane filtration process could
potentially meet the Bin 4
Cryptosporidium treatment
requirements of this proposal. These
criteria are described in more detail
below. EPA is developing a Membrane
Filtration Guidance Manual that
provides additional information and
procedures for meeting these criteria
(USEPA 2003e). A draft of this guidance
is available in the docket for today's
proposal (http://www.epa.gov/edocket/).
Definition of a Membrane Filtration
Process
For the purpose of this proposed rule,
membrane filtration is defined as a
pressure or vacuum driven separation
process in which paniculate matter
larger than 1 urn is rejected by a
nonfibrous, engineered barrier,
primarily through a size exclusion
mechanism, and which has a
measurable removal efficiency of a
target organism that can be verified
through the application of a direct
integrity test. This definition is intended
to include the common membrane
technology classifications:
microfiltration (MF), ultrafiltration (UF),
nanofiltration (NF), and reverse osmosis
(RO). MF and UF are low-pressure
membrane filtration processes that are
primarily used to remove particulate
matter and microbial contaminants. NF
and RO are membrane separation
processes that are primarily used to
remove dissolved contaminants through
a variety of mechanisms, but which also
remove particulate matter via a size
exclusion mechanism.
In today's proposal, the critical
distinction between membrane filtration
processes and bag and cartridge filters,
described in section IV.C.12, is that the
integrity of membrane filtration
processes can be directly tested. Based
on this distinction, EPA is proposing
that membrane material configured into
a cartridge filtration device that meets
the definition of membrane filtration
and that can be direct integrity tested
according to the criteria specified in this
section is eligible for the same removal
credit as a membrane filtration process.
Membrane devices can be designed in
a variety of configurations including
hollow-fiber modules, hollow-fiber
cassettes, spiral-wound elements,
cartridge filter elements, plate and frame
modules, and tubular modules among
others. In today's proposal, the generic
term module is used to refer to all of
these various configurations and is
defined as the smallest component of a
membrane unit in which a specific
membrane surface area is housed in a
device with a filtrate outlet structure. A
membrane unit is defined as a group of
membrane modules that share common
valving that allows the unit to be
isolated from the rest of the system for
the purpose of integrity testing or other
maintenance.
Challenge Testing
A challenge test is defined as a study
conducted to determine the removal
efficiency (i.e., log removal value) of the
membrane filtration media. The removal
efficiency demonstrated during
challenge testing establishes the
maximum removal credit that a
membrane filtration process is eligible
to receive, provided this value is less
than or equal to the maximum log
removal value that can be verified by
the direct integrity test (as described in
the following subsection). Challenge
testing is a product specific rather than
a site specific requirement. At the
discretion of the State, data from
challenge studies conducted prior to
promulgation of this regulation maybe
considered in lieu of additional testing.
However, the prior testing must have
been conducted in a manner that
demonstrates a removal efficiency for
Cryptosporidium commensurate with
the treatment credit awarded to the
process. Guidance for conducting
challenge testing to meet the
requirements of the rule is provided in
the Membrane Filtration Guidance
Manual (USEPA 2003e). Challenge
testing must be conducted according to
the following criteria:
• Challenge testing must be
conducted on a full-scale membrane
module identical in material and
construction to the membrane modules
proposed for use in full-scale treatment
facilities. Alternatively, challenge
testing may be conducted on a smaller
membrane module, identical in material
and similar in construction to the full-
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47703
scale module, if testing meets the other
requirements listed in this section.
• Challenge testing must be
conducted using Cryptosporidium
oocysts or a surrogate that has been
determined to be removed no more
efficiently than Cryptosporidium
oocysts. The organism or surrogate used
during challenge testing is referred to as
the challenge particulate. The
concentration of the challenge
particulate must be determined using a
method capable of discretely
quantifying the specific challenge
particulate used in the test. Thus, gross
water quality measurements such as
turbidity or conductivity cannot be
used.
• The maximum allowable feed water
concentration used during a challenge
test is based on the detection limit of the
challenge particulate in the filtrate, and
is determined according to the following
equation:
Maximum Feed Concentration = 3.16 x
10B x (Filtrate Detection Limit)
This will allow the demonstration of up
to 6.5 log removal during challenge
testing if the challenge particulate is
removed to the detection limit.
• Challenge testing must be
conducted under representative
hydraulic conditions at the maximum
design flux and maximum design
system recovery as specified by the
manufacturer. Flux is defined as the
flow per unit of membrane area.
Recovery is defined as the ratio of
filtrate volume produced by a
membrane to feed water volume applied
to a membrane over the course of an
uninterrupted operating cycle. An
operating cycle is bounded by two
consecutive backwash or cleaning
events. In the context of this rule,
recovery does not consider losses that
occur due to the use of filtrate in
backwashing or cleaning operations.
• Removal efficiency of a membrane
filtration process is determined from the
results of the challenge test, and
expressed in terms of log removal values
as defined by the following equation;
LRV = LOG,o(Cf} - LOG,o(Cp)
where LRV = log removal value
demonstrated during challenge testing;
Cf = the feed concentration used during
the challenge test; and Cp = the filtrate
concentration observed during the
challenge test. For this equation to be
valid, equivalent units must be used for
the feed and filtrate concentrations. If
the challenge particulate is not detected
in the filtrate, then the term Cp is set
equal to the detection limit. A single
LRV is calculated for each membrane
module evaluated during the test.
* The removal efficiency of a
membrane filtration process
demonstrated during challenge testing is
expressed as a log removal value
(LRVc-Tesi). If fewer than twenty
modules are tested, then LRVc-Tcst is
assigned a value equal to the lowest of
the representative LRVs among the
various modules tested. If twenty or
more modules are tested, then LRVc-Tcst
is assigned a value equal to the 10th
percentile of the representative LRVs
among the various modules tested. The
percentile is defined by [i/(n+l)] where
i is the rank of n individual data points
ordered lowest to highest. It may be
necessary to calculate the 10th
percentile using linear interpolation.
• A quality control release value
(QCRV) must be established for a non-
destructive performance test (e.g.,
bubble point test, diffusive airflow test,
pressure/vacuum decay test) that
demonstrates the Cryptosporidium
removal capability of the membrane
module. The performance test must be
applied to each production membrane
module that did not undergo a challenge
test in order to verify Cryptosporidium
removal capability. Production
membrane modules that do not meet the
established QCRV are not eligible for the
removal credit demonstrated during
challenge testing.
• Any significant modification to the
membrane filtration device (e.g., change
in the polymer chemistry of the
membrane) requires additional
challenge testing to demonstrate
removal efficiency of the modified
module and to define a new QCRV for
the nondestructive performance test.
Direct Integrity Testing
In order to receive removal credit for
Cryptosporidium, the removal efficiency
of a membrane filtration process must
be routinely verified through direct
integrity testing. A direct integrity test is
defined as a physical test applied to a
membrane unit in order to identify and
isolate integrity breaches. An integrity
breach is defined as one or more leaks
that could result in contamination of the
filtrate. The direct integrity test method
must be applied to the physical
elements of the entire membrane unit
including membranes, seals, potting
material, associated valving and piping,
and all other components which under
compromised conditions could result in
contamination of the filtrate.
The direct integrity tests commonly
used at the time of this proposal include
those that use an applied pressure or
vacuum (such as the pressure decay test
and diffusive airflow test), and those
that measure the rejection of a
particulate or molecular marker (such as
spiked particle monitoring). Today's
proposal does not stipulate the use of a
particular direct integrity test. Instead,
the direct integrity test must meet
performance criteria for resolution,
sensitivity, and frequency.
Resolution is defined as the smallest
leak that contributes to the response
from a direct integrity test. Any direct
integrity test applied to meet the
requirements of this proposed rule must
have a resolution of 3 urn or less. The
manner in which the resolution
criterion is met will depend on the type
of direct integrity test used. For
example, a pressure decay test can meet
the resolution criterion by applying a
net test pressure great enough to
overcome the bubble point of a 3 (im
hole. A direct integrity test that uses a
particulate or molecular marker can
meet the resolution criterion by
applying a marker of 3 u.m or smaller.
Sensitivity is defined as the maximum
log removal value that can be reliably
verified by the direct integrity test
(LRVoiT). The sensitivity of the direct
integrity test applied to meet the
requirements of this proposed rule must
be equal to or greater than the removal
credit awarded to the membrane
filtration process. The manner in which
LRVoir is determined will depend on
the type of direct integrity test used.
Direct integrity tests that use an applied
pressure or vacuum typically measure
the rate of pressure/vacuum decay or
the flow of air through an integrity
breach. The response from this type of
integrity test can be related to the flow
of water through an integrity breach
(Qbreach) during normal operation, using
procedures such as those described in
the Membrane Filtration Guidance
Manual (USEPA 2003e). Once Qbreach
has been determined, a simple dilution
model is used to calculate LRVorr for
the specific integrity test application, as
shown by the following equation:
LRVDIT = LOG,0(Qp/(VCF x Qbrcach))
where LRVDjr = maximum log removal
value that can be verified by a direct
integrity test; Qp = total design filtrate
flow from the membrane unit; Qbrcach =
flow of water from an integrity breach
associated with the smallest integrity
test response that can be reliably
measured; and VCF = volumetric
concentration factor.
The volumetric concentration factor is
the ratio of the suspended solids
concentration on the high pressure side
of the membrane relative to the feed
water, and is defined by the following
equation:
VCF = Cm/Cf
where Cm is the concentration of
particulate matter on the high pressure
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side of the membrane that remains in
suspension; and Cf is the concentration
of suspended particulate matter in the
feed water. The magnitude of the
concentration factor depends on the
mode of system operation and typically
ranges from 1 to 20. The Membrane
Filtration Guidance Manual presents
approaches for determining the
volumetric concentration factor for
different operating modes (USEPA
2003e).
Sensitivity of direct integrity tests that
use a particulate or molecular marker is
determined from the feed and filtrate
concentrations of the marker. The
LRVpiT for this type of direct integrity
test is calculated according to the
following equation:
LRVDIT = LOG,o{Cf} - LOG,o(Cp)
where LRVoiT = maximum log removal
value that can be verified by a direct
integrity test; Cr= the typical feed
concentration of the marker used in the
test; and Cp = the filtrate concentration
of the marker from an integral
membrane unit. For this equation to be
valid, equivalent units must be used for
the feed and filtrate concentrations. An
ideal particulate or molecular marker
would be completely removed by an
integral membrane unit.
If the sensitivity of the direct integrity
test is such that LRVDir is less than
LRVc-Tesi, LRVD]T establishes the
maximum removal credit that a
membrane filtration process is eligible
to receive. Conversely, if LRVoir for a
direct integrity test is greater than
LRVc-jcst, LRVc-Tcsi establishes the
maximum removal credit.
A control limit is defined as an
integrity test response which, if
exceeded, indicates a potential problem
with the system and triggers a response.
Under this proposal, a control limit for
a direct integrity test must be
established that is indicative of an
integral membrane unit capable of
meeting the Cryptosporidium removal
, credit awarded by the State. If the
control limit for the direct integrity test
is exceeded, the membrane unit must be
taken off-line for diagnostic testing and
repair. The membrane unit could only
be returned to service after the repair
has been completed and confirmed
through the application of a direct
integrity test.
The frequency of direct integrity
testing specifies how often the test is
performed over an established time
interval. Most direct integrity tests
available at the time of this proposal are
applied periodically and must be
conducted on each membrane unit at a
frequency of not less than once every 24
hours while the unit is in operation. If
continuous direct integrity test methods
become available that also meet the
sensitivity and resolution criteria
described earlier, they may be used in
lieu of periodic testing.
EPA is proposing that at a minimum,
a monthly report must be submitted to
the State summarizing all direct
integrity test results above the control
limit associated with the
Cryptosporidium removal credit
awarded to the process and the
corrective action that was taken in each
case.
Continuous Indirect Integrity
Monitoring
The majority of currently available
direct integrity test methods are applied
periodically since the membrane unit
must be taken out of service to conduct
the test. In order to provide some
measure of process performance
between direct integrity testing events,
continuous indirect integrity monitoring
is required. Indirect integrity monitoring
is defined as monitoring some aspect of
filtrate water quality that is indicative of
the removal of particulate matter. If a
continuous direct integrity test is
implemented that meets the resolution
and sensitivity criteria described
previously, continuous indirect integrity
monitoring is not required. Continuous
indirect integrity monitoring must be
conducted according to the following
criteria:
• Unless the State approves an
alternative parameter, continuous
indirect integrity monitoring must
include continuous filtrate turbidity
monitoring.
• Continuous monitoring is defined
as monitoring conducted at a frequency
of no less than once every 15 minutes.
• Continuous monitoring must be
separately conducted on each
membrane unit.
• If indirect integrity monitoring
includes turbidity and if the filtrate
turbidity readings are above 0.15 NTU
for a period greater than 15 minutes (i.e.,
two consecutive 15-minute readings
above 0.15 NTU), direct integrity testing
must be performed on the associated
membrane units.
• If indirect integrity monitoring
includes a State-approved alternative
parameter and if the alternative
parameter exceeds a State-approved
control limit for a period greater than 15
minutes, direct integrity testing must be
performed on the associated membrane
units.
• EPA is proposing that at a
minimum, a monthly report must be
submitted to the primacy agency
summarizing all indirect integrity
monitoring results triggering direct
integrity testing and the corrective
action that was taken in each case.
b. How was this proposal developed?
The Stage 2 M-DBP Agreement in
Principle recommends that EPA develop
criteria to award Cryptosporidium
removal credit to membrane filtration
processes. Today's proposal and the
supporting guidance are consistent with
the Agreement.
A number of studies have been
conducted which have demonstrated
the ability of membrane filtration
processes to remove pathogens,
including Cryptosporidium, to below
detection levels. A literature review
summarizing the results of several
comprehensive studies was conducted
by EPA and is presented in Low-
Pressure Membrane Filtration for
Pathogen Removal: Application,
Implementation, and Regulatory Issues
(USEPA 2001h). Many of these studies
used Cryptosporidium seeding to
demonstrate removal efficiencies as
high as 7 log. The collective results from
these studies demonstrate that an
integral membrane module, i.e., a
membrane module without any leaks or
defects, with an exclusion characteristic
smaller than Cryptosporidium, is
capable of removing this pathogen to
below detection in the filtrate,
independent of the feed concentration.
Some filtration devices have used
membrane media in a cartridge filter
configuration; however, few data are
available documenting their ability to
meet the requirements for membrane
filtration described in section IV.C.ll.a
of this preamble. However, in one study
reported by Dwyer et a]. (2001), a
membrane cartridge filter demonstrated
Cryptosporidium removal efficiencies in
excess of 6 log. This study illustrates the
potentially high removal capabilities of
membrane filtration media configured
into a cartridge filtration device, thus
providing a basis for awarding removal
credits to these devices under the
membrane filtration provision of the
rule, assuming that the device meets the
definition of a membrane filtration
process as well as the direct integrity
test requirements.
Today's proposal requires challenge
testing of membrane filtration processes
used to remove Cryptosporidium. As
noted in section III.D, EPA believes this
is necessary due to the proprietary
nature of these systems and the lack of
any uniform criteria for establishing the
exclusion characteristic of a membrane.
Challenge testing addresses the lack of
a standard approach for characterizing
membranes by requiring direct
verification of removal efficiency. The
proposed challenge testing is product-
specific and not site-specific since the
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47705
intent of this testing is to demonstrate
the removal capabilities of the
membrane product rather than evaluate
the feasibility of implementing
membrane treatment at a specific plant.
Testing can be conducted using a full-
scale module or a smaller module if the
results from the small-scale module test
.can be related to full-scale module
performance. Most challenge studies
presented in the literature have used
full-scale modules, which provide
results that can be directly related to
full-scale performance. However, use of
smaller modules is considered feasible
in the evaluation of removal efficiency,
and a protocol for challenge testing
using small-scale modules has been
proposed (NSF, 2002a). Since the
removal efficiency of an integral
membrane is a direct function of the
membrane material, it may be possible
to use a small-scale module containing
the same membrane fibers or sheets
used in full-scale modules for this
evaluation. However, it will be
necessary to relate the results of the
small-scale module test to the
nondestructive performance test quality
control release value that will be used
to validate full-scale production
modules.
Challenge testing with either
Cryptosporidium oocysts or a surrogate
is permitted. Challenge testing with
Cryptosporidium clearly provides direct
verification of removal efficiency for
this pathogen; however, several studies
have demonstrated that surrogates can
provide an accurate or conservative
measure of Cryptosporidium removal
efficiency. Since removal of paniculate
matter larger than 1 urn by a membrane
filtration process occurs primarily via a
size exclusion mechanism, the shape
and size distribution of the surrogate
must be selected such that the surrogate
is not removed to a greater extent than
the target organism. Surrogates that have
been successfully used in challenge
studies include polystyrene
microspheres and bacterial endospores.
The bacterial endospore, Bacillus
subtilis, has been used as a surrogate for
Cryptosporidium oocysts during
challenge studies evaluating pathogen
removal by physical treatment
processes, including membrane
filtration (Rice et al. 1996, Fox et al
1998, Trimboli et al 1999, Owen et al,
1999). Studies evaluating cartridge
filters have demonstrated that
polystyrene microspheres can provide
an accurate or conservative measure of
removal efficiency (Long, 1983, Li et al.
1997). Furthermore, the National
Sanitation Foundation (NSF)
Environmental Technology Verification
(ETV) protocol for verification testing
for physical removal of microbiological
and particulate contaminants specifies
the use of polymeric microspheres of a
known size distribution (NSF 2002b).
Guidance on selection of an appropriate
surrogate for establishing a removal
efficiency for Cryptosporidium during
challenge testing is presented in the
Membrane Filtration Guidance Manual
(USEPA 2003e).
The design of the proposed challenge
studies is similar to the design of the
seeding studies described in the
literature cited earlier. Seeding studies
are used to challenge the membrane
module with pathogen levels orders of
magnitude higher than those
encountered in natural waters.
However, elevated feed concentrations
can lead to artificially high estimates of
removal efficiency. To address this
issue, the feed concentration applied to
the membrane during challenge studies
is capped at a level that will allow the
demonstration of up to 6.5 log removal
efficiency if the challenge particulate is
removed to the detection level.
Because challenge testing with
Cryptosporidium or a surrogate is not
conducted on every membrane module,
it is necessary to establish criteria for a
non-destructive performance test that
can be applied to all production
membrane modules. Results from a non-
destructive test, such as a bubble point
test, that are correlated with the results
of challenge testing can be used to
establish a quality control release value
(QCRV) that is indicative of the ability
of a membrane filtration process to
remove Cryptosporidium. The non-
destructive test and QCRV can be used
to verify the Cryptosporidium removal
capability of modules that are not
challenge tested. Most membrane
manufacturers have already adapted
some form of non-destructive testing for
product quality control purposes and
have established a quality control
release value that is indicative of an
acceptable product. It may be possible
to apply these existing practices for the
purpose of verifying the capability of a
membrane filtration process to remove
Cryptosporidium.
Challenge testing provides a means of
demonstrating the removal efficiency of
an integral membrane module; however,
defects or leaks in the membrane or
other system components can result in
contamination of the filtrate unless they
are identified, isolated, and repaired. In
order to verify continued performance
of a membrane system, today's proposal
requires direct integrity testing of
membrane filtration processes used to
meet Cryptosporidium treatment
requirements. Direct integrity testing is
required because it is a test applied to
the physical membrane module and,
thus, a direct evaluation of integrity.
Furthermore, direct integrity methods
are the most sensitive integrity
monitoring methods commonly used at
the time of this proposal (Adham et al
1995).
The most common direct integrity
tests apply a pressure or a vacuum to
one side of a fully wetted membrane
and monitor either the pressure decay or
the volume of displaced fluid over time.
However, the proprietary nature of these
systems makes it impractical to define a
single direct integrity test methodology
that is applicable to all existing and
future membrane products. Therefore,
performance criteria have been
established for any direct integrity test
methodology used to verify the removal
efficiency of a membrane system. These
performance criteria are resolution,
sensitivity, and frequency.
As stated previously, the resolution of
an integrity test refers to the smallest
leak that contributes to the response
from an integrity test. For example, in
a pressure decay integrity test,
resolution is the smallest leak that
contributes to pressure loss during the
test. Today's proposal specifies a
resolution of 3 um or less, which is
based on the size of Cryptosporidium
oocysts. This requirement ensures that a
leak that could pass a Cryptosporidium
oocyst would contribute to the response
from an integrity test.
The sensitivity of an integrity test
refers to the maximum log removal that
can be reliably verified by the test.
Again using the pressure decay integrity
test as an example, the method
sensitivity is a function of the smallest
pressure loss that can be detected over
a membrane unit. Today's proposal
limits the log removal credit that a
membrane filtration process is eligible
to receive to the maximum log removal
value that can be verified by a direct
integrity test.
In order to serve as a useful process
monitoring tool for assuring system
integrity, it is necessary to establish a
site-specific control limit for the
integrity test that corresponds to the log
removal awarded to the process. A
general approach for establishing this
control limit for some integrity test
methods is presented in guidance;
however, the utility will need to work
with the membrane manufacturer and
State to establish a site-specific control
limit appropriate for the integrity test
used and level of credit awarded.
Excursions above this limit indicate a
potential integrity breach and would
trigger removal of the suspect unit from
service followed by diagnostic testing
and subsequent repair, as necessary.
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Most direct integrity tests available at
the time of this proposal must be
applied periodically since it is
necessary to take the membrane unit out
of service to conduct the test. Today's
proposal establishes the minimum
frequency for performing a direct
integrity test at once per 24 hours.
Currently, there is no standard
frequency for direct integrity testing that
has been adopted by all States and
membrane treatment facilities. In a
recent survey, the required frequency of
integrity testing was found to vary from
once every four hours to once per week;
however, the most common frequency
for conducting a direct integrity test was
once every 24 hours (USEPA 2001h).
Specifically, 10 out of 14 States that
require periodic direct integrity testing
specify a frequency of once every 24
hours. Furthermore, many membrane
manufacturers of systems with
automated integrity test systems set up
the membrane units to automatically
perform a direct integrity test once per
24 hours. EPA has concluded that the 24
hour direct integrity test frequency
ensures that removal efficiency is
verified on a routine basis without
resulting in excessive system downtime.
Since most direct integrity tests are
applied periodically, it is necessary to
implement some level of continuous
monitoring to assess process
performance between direct integrity
test events. In the absence of a
continuous direct integrity test,
continuous indirect integrity monitoring
is required. Although it has been shown
that commonly used indirect integrity
monitoring methods lack the sensitivity
to detect small integrity breaches that
are of concern (Adham etal 1995), they
can detect large breaches and provide
some assurance that a major failure has
not occurred between direct integrity
test events. Turbidity monitoring is
proposed as the method of indirect
integrity monitoring unless the State
approves an alternate approach.
Available data indicate that an integral
membrane filtration process can
consistently produce water with a
turbidity less than 0.10 NTU, regardless
of the feedwater quality. Consequently,
EPA is proposing that exceedance of a
filtrate turbidity value of 0.15 NTU
triggers direct integrity testing to verify
and isolate the integrity breach.
c. Request for comment. EPA requests
comment on the following issues:
• EPA is proposing to include
membrane cartridge filters that can be
direct integrity tested under the
definition of a membrane filtration
process since one of the key differences
between membrane filtration processes
and bag and cartridge filters, within the
context of this regulation, is the
applicability of direct integrity test
methods to the filtration process. EPA
requests comment on the inclusion of
membrane cartridge filters that can be
direct integrity tested under the
definition of a membrane filtration
process in this rule.
• The applicability of the proposed
Cryptosporidium removal credits and
performance criteria to Giardia lamblia,
• Appropriate surrogates, or the
characteristics of appropriate surrogates,
for use in challenge testing. EPA
requests data or information
demonstrating the correlation between
removal of a proposed surrogate and
removal of Cryptosporidium oocysts.
• The use of a non-destructive
performance test and associated quality
control release values for demonstrating
the Cryptosporidium removal capability
of membrane modules that are not
directly challenge tested.
• The appropriateness of the
minimum direct integrity test frequency
of once per 24 hours.
• The proposed minimum reporting
frequency for direct integrity testing
results above the control limit and
indirect integrity monitoring results that
trigger direct integrity monitoring.
12. Bag and Cartridge Filtration
a. What is EPA proposing today? EPA
is proposing criteria for awarding
Cryptosporidium removal credit of 1 log
for bag filtration processes and 2 log for
cartridge filtration processes. To receive
removal credit the process must: (1)
Meet the basic definition of a bag or
cartridge filter and (2) have removal
efficiency established through challenge
testing.
Definition of a Bag or Cartridge Filter
For the purpose of this rule, bag and
cartridge filters are defined as pressure
driven separation processes that remove
particulate matter larger than 1 um
using an engineered porous filtration
media through either surface or depth
filtration.
The distinction between bag filters
and cartridge filters is based on the type
of filtration media used and the manner
in which the devices are constructed.
Bag filters are typically constructed of a
non-rigid, fabric filtration media housed
in a pressure vessel in which the
direction of flow is from the inside of
the bag to outside. Cartridge filters are
typically constructed as rigid or semi-
rigid, self-supporting filter elements
housed in pressure vessels in which
flow is from the outside of the cartridge
to the inside.
Although all filters classified as
cartridge filters share similarities with
respect to their construction, there are
significant differences among the
various commercial cartridge filtration
devices. From a public health
perspective, an important distinction
among these filters is the ability to
directly test the integrity of the filtration
system in order to verify that there are
no leaks that could result in
contamination of the filtrate. Any
membrane cartridge filtration device
that can be direct integrity tested
according to the criteria specified in
section IV.C.ll.a is eligible for removal
credit as a membrane, subject to the
criteria specified in that section. Section
IV.C.12 applies to all bag filters, as well
as to cartridge filters which cannot be
direct integrity tested.
Challenge Testing
In order to receive 1 log removal
credit, a bag filter must have a
demonstrated removal efficiency of 2
log or greater for Cryptosporidium.
Similarly, to receive 2 log removal
credit, a cartridge filter must have a
demonstrated removal efficiency of 3
log or greater for Cryptosporidium. The
1 log factor of safety is applied to the
removal credit awarded to these
filtration devices based on two primary
considerations. First, the removal
efficiency of some bag and cartridge
filters has been observed to vary by
more than 1 log over the course of
operation (Li etal 1997, NSF 2001a,
NSF 200lb). Second, bag and cartridge
filters are not routinely direct integrity
tested during operation in the field;
hence, there is no means of verifying the
removal efficiency of filtration units
during routine use. Based on these
considerations, a conservative approach
to awarding removal credit based on
challenge test results is warranted.
Removal efficiency must be
demonstrated through a challenge test
conducted on the bag or cartridge filter
proposed for use in full-scale drinking
water treatment facilities for removal of
Cryptosporidium. Challenge testing is
required for specific products and is not
intended to be site specific. At the
discretion of the State, data from
challenge studies conducted prior to
promulgation of this regulation may be
considered in lieu of additional testing.
However, the prior testing must have
been conducted in a manner that
demonstrates a removal efficiency for
Cryptosporidium commensurate with
the treatment credit awarded to the
process. Guidance on conducting
challenge studies to demonstrate the
Cryptosporidium removal efficiency of
filtration units is presented in the
Membrane Filtration Guidance Manual
(USEPA 2003e). Challenge testing must
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be conducted according to the following
criteria:
• Challenge testing must be
conducted on a full-scale filter element
identical in material and construction to
the filter elements proposed for use in
full-scale treatment facilities.
• Challenge testing must be
conducted using Cryptosporidium
oocysts or a surrogate which is removed
no more efficiently than
Cryptosporidium oocysts. The organism
or surrogate used during challenge
testing is referred to as the challenge
particulate. The concentration of the
challenge particulate must be
determined using a method capable of
discretely quantifying the specific
organism or surrogate used in the test,
i.e., gross water quality measurements
such as turbidity cannot be used.
• The maximum allowable feed water
concentration used during a challenge
test is based on the detection limit of the
challenge particulate in the filtrate and
calculated using one of the following
equations.
For bag filters:
Maximum Feed Concentration = 3.16 x
103 x (Filtrate Detection Limit)
For cartridge filters:
Maximum Feed Concentration = 3.16 x
10" x (Filtrate Detection Limit)
This will allow the demonstration of
up to 3.5 log removal for bag filters and
4.5 log removal for cartridge filters
during challenge testing if the challenge
particulate is removed to the detection
limit.
• Challenge testing must be
conducted at the maximum design flow
rate specified by the manufacturer.
• Each filter must be tested for a
duration sufficient to reach 100% of the
terminal pressure drop, a parameter
specified by tbe manufacturer which
establishes the end of the useful life of
the filter. In order to achieve terminal
pressure drop during the test, it will be
necessary to add particulate matter to
the test solution, such as fine carbon test
dust or bentonite clay particles.
• Each filter must be challenged with
the challenge particulate during three
periods over the filtration cycle: within
2 hours of start-up after a new bag or
cartridge filter has been installed, when
the pressure drop is between 45 and
55% of the terminal pressure drop, and
at the end of the run after the pressure
drop has reached 100% of the terminal
pressure drop.
• Removal efficiency of a bag or
cartridge filtration process is
determined from the results of the
challenge test, and expressed in terms of
log removal values as defined by the
following equation:
LRV = LOGlo(Cf)-LOGio(Cp)
where LRV - log removal value
demonstrated during challenge testing;
Cf = the feed concentration used during
the challenge test; and Cp = the filtrate
concentration observed during the
challenge test. For this equation to be
valid, equivalent units must be used for
the feed and filtrate concentrations. If
the challenge particulate is not detected
in the filtrate, then the term Cp is set
equal to the detection limit. An LRV is
calculated for each filter evaluated
during the test.
• In order to receive treatment credit
for Cryptosporidium under this
proposed rule, challenge testing must
demonstrate a removal efficiency of 2
log or greater for bag filtration and 3 log
or greater for cartridge filtration. If fewer
than twenty filters are tested, then
removal efficiency of the process is set
equal to the lowest of the representative
LRVs among the various filters tested. If
twenty or more filters are tested, then
removal efficiency of the process is set
equal to the 10th percentile of the
representative LRVs among the various
filters tested. The percentile is defined
by (i/(n+l)] where i is the rank of n
individual data points ordered lowest to
highest. It may be necessary to calculate
the 10th percentile using linear
interpolation.
• Any significant modification to the
filtration unit (e.g., changes to the
filtration media, changes to the
configuration of the filtration media,
significant modifications to the sealing
system) would require additional
challenge testing to demonstrate
removal efficiency of the modified unit.
b. How was this proposal developed?
The Stage 2 M-DBP Agreement in
Principle recommended that EPA
develop criteria for awarding
Cryptosporidium removal credits of 1
log for bag filters and 2 log for cartridge
filters. Today's proposal is consistent
with the Agreement.
A limited amount of published data
are available regarding the removal
efficiency of bag and cartridge filters
with respect to Cryptosporidium oocysts
or suitable surrogates. The relevant
studies identified in the literature are
summarized in Table IV-18.
TABLE IV-18— RESULTS FROM STUDIES OF Cryptosporidium OR SURROGATE REMOVAL BY BAG AND CARTRIDGE
FILTERS
Process
Log removal
Organism/surrogate
Reference
Bag and cartridge filtration in se-
ries.
Cartridge filtration
Cartridge filtration
Cartridge filtration
Cartridge filtration
Cartridge filtration
Cartridge filtration
Prefilter and bag filter in series
Bag filtration
Bag filtration
Bag filtration
1.1 to 2.1
3 to 6 jim spheres
3.5 (average)
3.3 (average)
1.1 to 3.3
0.5 to 3.6
2.3 to 2.8
2.7 to 3.7
1.9 to 3.2
-3.0
0.5 to 3.6
0.5 to 2.0
Cryptosporidium
Cryptosporidium
Cryptosporidium
5.7 jim spheres .
Cryptosporidium
Cryptosporidium
3.7 jim spheres .
Cryptosporidium
Cryptosporidium
4.5 jam spheres .
NSF 2001a.
Enriquez et al. 1999.
Roessler, 1998.
Schaubetal. 1993.
Long, 1983.
Ciardelli, 1996 a.
Ciardelli, 1996b.
NSF 2001b.
Cornwell and LeChevallier, 2002.
Li et al. 1997.
Goodrich et al. 1995.
These data demonstrate highly
variable removal performance for these
processes, ranging from 0.5 log to 3.6 log
for both bag and cartridge filtration.
Results of these studies also show no
correlation between the pore size rating
established by the manufacturer and the
removal efficiency of a filtration device.
In a study evaluating two cartridge
filters, both with a pore size rating of 3
jj.m, a 2 log difference in
Cryptosporidium oocyst removal was
observed between the two filters
(Schaub et al. 1993). Another study
evaluated seventeen cartridge filters
with a range of pore size ratings from 1
u.m to 10 jam and found no correlation
with removal efficiency (Long, 1983). Li
et al. (1997) evaluated three bag filters
with similar pore size ratings and
observed a 3 log difference in
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Cryptosporidium oocyst removal among
them. These results indicate that bag
and cartridge filters may be capable of
achieving removal of oocysts in excess
of 3 log; however, performance can vary
significantly among products and there
appears to be no correlation between
pore size rating and removal efficiency.
Based on available data, specific
design criteria that correlate to removal
efficiency cannot be derived for bag and
cartridge filters. Furthermore, the
removal efficiency of these proprietary
devices can be impacted by product
variability, increasing pressure drop
over the filtration cycle, flow rate, and
other operating conditions. The data in
Table IV-18 were generated from
studies performed under a variety of
operating conditions, many of which
could not be considered conservative (or
worst-case) operation. These
considerations lead to the proposed
challenge testing requirements which
are intended to establish a product-
specific removal efficiency.
The proposed challenge testing is
product-specific and not site-specific
since the intent of this testing is to
demonstrate the removal capabilities of
the filtration device rather than evaluate
the feasibility of implementing the
technology at a specific plant. Challenge
testing must be conducted using full-
scale filter elements in order to evaluate
the performance of the entire unit,
including the filtration media, seals,
filter housing and other components
integral to the filtration system. This
will improve the applicability of
challenge test results to full-scale
performance. Multiple filters of the
same type can be tested to provide a
better statistical basis for estimating
removal efficiency.
Either Cryptosporidium oocysts or a
suitable surrogate could be used as the
challenge particulate during the test.
Challenge testing with Cryptosporidium
provides direct verification of removal
efficiency; however, some studies have
demonstrated that surrogates, such as
polystyrene microspheres, can provide
an accurate or conservative measure of
removal efficiency (Long 1983, Li et al.
1997). Furthermore, the National
Sanitation Foundation (NSF)
Environmental Technology Verification
(ETV) protocol for verification testing
for physical removal of microbiological
and particulate contaminants specifies
the use of polymeric microspheres of a
known size distribution (NSF 2002b).
Guidance on selection of an appropriate
surrogate for establishing a removal
efficiency for Cryptosporidium during
challenge testing is presented in the
Membrane Filtration Guidance Manual
(USEPA 2003e).
In order to demonstrate a removal
efficiency of at least 2 or 3 log for bag
or cartridge filters, respectively, it will
likely be necessary to seed the challenge
particulate into the test solution. A
criticism of published studies that use
this approach is that the seeded levels
are orders of magnitude higher than
those encountered in natural waters and
this could potentially lead to artificially
high estimates of removal efficiency. To
address this issue, the feed
concentration applied to the filter
during challenge studies is capped at a
level that will allow the demonstration
of a removal efficiency up to 4.5 log for
cartridge filters and 3.5 log for bag filters
if the challenge particulate is removed
to the detection level.
The removal efficiency of some bag
and cartridge filtration devices has been
. shown to decrease over the course of a
filtration cycle due to the accumulation
of solids and resulting increase in
pressure drop. As an example, Li et al.
(1997) observed that the removal of 4.5
um microspheres by a bag filter
decreased from 3.4 log to 1.3 log over
the course of a filtration cycle. Studies
evaluating bag and cartridge filtration
under the NSF ETV program have also
shown a degradation in removal
efficiency over the course of the
filtration cycle (NSF 2001a and 2001b).
In order to evaluate this potential
variability, the challenge studies are
designed to assess removal efficiency
during three periods of a filtration cycle:
within two hours of startup following
installation of a new filter, between 45%
and 55% of terminal pressure drop, and
at the end of the run after 100% of
terminal pressure drop is realized.
Although challenge testing can
provide an estimate of removal
efficiency for a bag or cartridge filtration
process, it is not feasible to conduct a
challenge test on every production filter.
This, coupled with variability within a
product line, could result in some
production filters that do not meet the
removal efficiency demonstrated during
challenge testing. For membrane
filtration processes, this problem is
addressed through the use of a quality
control release value established for a
non-destructive test, such as a bubble
point test or pressure hold test, that is
correlated to removal efficiency. Since
the non-destructive test can be applied
to all production membrane modules,
this provides a feasible means of
verifying the performance of every
membrane module used by a PWS.
However, the non-destructive tests
applied to membrane filtration
processes cannot be applied to most bag
and cartridge filtration devices, and EPA
is not aware of an alternative non-
destructive test that can be used with
these devices.
Typical process monitoring for bag
and cartridge filtration systems includes
turbidity and pressure drop to
determine when filters must be
replaced. However, the applicability of
either of these process monitoring
parameters as tools for verifying
removal of Cryptosporidium has not
been demonstrated. Only a few bag or
cartridge filtration studies have
attempted to correlate turbidity removal
with removal of Cryptosporidium
oocysts or surrogates. Li et a/. (1997)
found that the removal efficiency for
turbidity was consistently lower than
removal efficiency for oocysts or
microspheres for the three bag filters
evaluated. Furthermore, none of the
filters was capable of consistently
producing a filtered water turbidity
below 0.3 NTU for the waters evaluated.
The contribution to turbidity from
particles much smaller than
Cryptosporidium oocysts, and much
smaller than the mesh size of the filter,
make it difficult to correlate removal of
turbidity with removal of
Cryptosporidium. Consequently, EPA is
proposing a 1 log factor of safety to be
applied to challenge test results in
awarding treatment credit to bag and
cartridge filters, and is not proposing
integrity monitoring requirements for
these devices.
c. Request for comment. EPA requests
comment on the following issues
concerning bag and cartridge filters:
• The performance of bag and
cartridge filters in removing
Cryptosporidium through all differential
pressure ranges in a filter run—EPA
requests laboratory and field data, along
with associated quality assurance and
quality control information, that will
support a determination of the
appropriate level of Cryptosporidium
removal credit to award to these
technologies.
• The performance of bag and
cartridge filters in removing
Cryptosporidium when used in series
with other bag or cartridge filters—EPA
requests laboratory and field data, along
with associated quality assurance and
quality control information, that will
support a determination of the
appropriate level of Cryptosporidium
removal credit to award to these
technologies when used in series.
• Appropriate surrogates, or the
characteristics of appropriate surrogates,
for use in challenge testing bag and
cartridge filters—EPA requests data or
information demonstrating the
correlation between removal of a
proposed surrogate and removal of
Cryptosporidium oocysts.
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• The availability of non-destructive
tests that can be applied to bag and
cartridge filters to verify the removal
efficiency of production filters that are
not directly challenge tested—EPA
requests data or information
demonstrating the correlation between a
proposed non-destructive test and the
removal of Cryptosporidium oocysts.
• The applicability of pressure drop
monitoring, filtrate turbidity
monitoring, or other process monitoring
and process control procedures to verify
the integrity of bag and cartridge
filters—EPA requests data or
information demonstrating the
correlation between a proposed process
monitoring tool and the removal of
Cryptosporidium oocysts.
• The applicability of bag and
cartridge filters to different source water
types and treatment scenarios.
• The applicability of the proposed
Cryptosporidium removal credits and
testing criteria to Giardia lamblia.
• The use of a 1 log factor of safety
for awarding credit to bag and cartridge
filters—EPA requests comment on
whether this is an appropriate factor of
safety to account for the inability to
conduct integrity monitoring of these
devices, as well as the variability in
removal efficiency observed over the
course of a filtration cycle for some
filtration devices. This inability creates
uncertainty regarding both changes in
the performance of a given filter during
use and variability in performance
among filters in a given product line. If
the 1 log factor of safety is higher than
necessary to account for these factors,
should the Agency establish a lower
value, such as a 0.5 log factor of safety?
13. Secondary Filtration
a. What is EPA proposing today?
Today's proposal allows systems using
a second filtration stage to receive an
additional 0.5 log Cryptosporidium
removal credit. To be eligible for this
credit, the secondary filtration must
consist of rapid sand, dual media,
granular activated carbon (GAG), or
other fine grain media in a separate
stage following rapid sand or dual
media filtration. A cap, such as GAG, on
a single stage of filtration will not
qualify for this credit. In addition, the
first stage of filtration must be preceded
by a coagulation step, and both stages
must treat 100% of the flow.
b. How was this proposal developed?
Although not addressed in the
Agreement in Principle, EPA has
determined that secondary filtration
meeting the criteria described in this
section will achieve additional removal
of Cryptosporidium oocysts.
Consequently, additional removal credit
may be appropriate. As reported in
section III.D, many studies have shown
that rapid sand filtration preceded by
coagulation can achieve significant
removal of Cryptosporidium (Patania et
al 1995, Nieminski and Ongerth 1995,
Ongerth and Pecoraro 1995,
LeChevallier and Norton 1992,
LeChevallier et al. 1991, Dugan et al
2001, Nieminski and Bellamy 2000,
McTigue et al 1998, Patania et al. 1999,
Huck et al. 2000, Emelko et al 2000).
While these studies evaluated only a
single stage of filtration, the same
mechanisms of removal are expected to
occur in a second stage of granular
media filtration.
EPA received data from the City of
Cincinnati, OH, on the removal of
aerobic spores through a conventional
treatment facility that employs GAG
contactors for DBF, taste, and odor
control after rapid sand filtration. As
described previously, a number of
studies (Dugan et al. 2001, Emelko et al
1999 and 2000, Yates et al 1998,
Mazounie et al 2000} have
demonstrated that aerobic spores are a
conservative indicator of
Cryptosporidium removal by granular
media filtration when preceded by
coagulation.
During the period of 1999 and 2000,
the mean values of reported spore
concentrations in the influent and
effluent of the Cincinnati GAG
contactors were 35.7 and 6.4 cfu/100
mL, respectively, indicating an average
removal of 0.75 log across the
contactors. Approximately 16% of the
GAG filtered water results were below
detection limit (1 cfu/100 mL) so the
actual log spore removal may have been
greater than indicated by these results.
In summary, studies in the cited
literature demonstrate that a fine
granular media filter preceded by
coagulation can achieve high levels of
Cryptosporidium removal. Data on
increased removal resulting from a
second stage of filtration are limited,
and there is uncertainty regarding how
effective a second stage of filtration will
be in reducing levels of microbial
pathogens that are not removed by the
first stage of filtration. However, EPA
has concluded that a secondary
filtration process can achieve 0.5 log or
greater removal of Cryptosporidium
based on (l) the theoretical
consideration that the same mechanisms
of pathogen removal will be operative in
both a primary and secondary filtration
stage, and (2) data from the City of
Cincinnati showing aerobic spore
removal in GAG contactors following
rapid sand filtration. Therefore, EPA
believes it is appropriate to propose 0.5
log additional Cryptosporidium
treatment credit for systems using
secondary filtration which meets the
criteria of this section.
c. Request for comment. The Agency
requests comment on awarding a 0.5 log
Cryptosporidium removal credit for
systems using secondary filtration,
including the design and operational
criteria required to receive the log
removal credit. EPA specifically
requests comment on the following
issues:
• Should there be a minimum
required depth for the secondary filter
(e.g., 24 inches) in order for the system
to receive credit?
• Should systems be eligible to
receive additional Cryptosporidium
treatment credit within the microbial
toolbox for both a second clarification
stage (e.g., secondary filtration, second
stage sedimentation) and lower finished
water turbidity, given that additional
particle removal achieved by the second
clarification stage will reduce finished
water turbidity?
14. Ozone and Chlorine Dioxide
a. What is EPA proposing today?
Similar to the methodology used for
estimating log inactivation of Giardia
lamblia by various chemical
disinfectants in 40 CFR 141.74, EPA is
proposing the CT concept for estimating
log inactivation of Cryptosporidium by
chlorine dioxide or ozone. In today's
proposal, systems must determine the
total inactivation of Cryptosporidium
each day the system is in operation,
based on the CT values in Table IV-19
for ozone and Table IV-20 for chlorine
dioxide. The parameters necessary to
determine the total inactivation of
Cryptosporidium must be monitored as
stated in 40 CFR 141.74(b)(3)(i), (iii),
and (iv), which is as follows:
* The temperature of the disinfected
water must be measured at least once
per day at each residual disinfectant
concentration sampling point.
• The disinfectant contact time(s)
("T") must be determined for each day
during peak hourly flow.
• The residual disinfectant
concentration(s) ("C") of the water
before or at the first customer must be
measured each day during peak hourly
flow.
Systems may have several
disinfection segments (the segment is
defined as a treatment unit process with
a measurable disinfectant residual level
and a liquid volume) in sequence along
the treatment train. In determining the
total log inactivation, the system may
calculate the log inactivation for each
disinfection segment and use the sum of
the log inactivation estimates of
Cryptosporidium achieved through the
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Federal Register/Vol. 68, No. 154/Monday, August 11, 2003/Proposed Rules
plant. The Toolbox Guidance Manual,
available in draft with today's proposal,
provides guidance on methodologies for
determining CT values and estimating
log inactivation for different
disinfection reactor designs and
operations.
TABLE IV-19 — CT VALUES FOR Cryptosporidium INACTIVATION BY OZONE
Log credit
0 5
1 o
1 5
2 0
2 5
3.0
Water Temperature, °C 1
<=0.5
12
24
36
48
60
72
1
12
23
35
46
58
69
2
10
21
31
42
52
63
3
9.5
19
29
38
48
57
5
7.9
16
24
32
40
47
7
6.5
13
20
26
33
39
10
4.9
9.9
15
20
25
30
15
3.1
6.2
9.3
12
16
19
20
2.0
3.9
5.9
7.8
9.8
12
25
1.2
2.5
3.7
4.9
6.2
7.4
1 CT values between the indicated temperatures may be determined by interpolation.
TABLE IV-20 — CT VALUES FOR Cryptosporidium INACTIVATION BY CHLORINE DIOXIDE
Log credit
0 5
1 o
1 5
2 0
2 5
3.0
Water Temperature, °C 1
<=0.5
319
637
956
1275
1594
1912
1
305
610
915
1220
1525
1830
2
279
558
838
1117
1396
1675
3
256
511
767
1023
1278
1534
5
214
429
643
858
1072
1286
7
180
360
539
719
899
1079
10
138
277
415
553
691
830
15
89
179
268
357
447
536
20
58
116
174
232
289
347
25
38
75
113
150
188
226
1 CT values between the indicated temperatures may be determined by interpolation.
The system may demonstrate to the
State, through the use of a State-
approved protocol for on-site
disinfection challenge studies or other
information satisfactory to the State,
that CT values other than those
specified in Tables IV-19 or IV-20 are
adequate to demonstrate that the system
is achieving the required log
inactivation of Cryptosporidium.
Protocols for making such
demonstrations are available in the
Toolbox Guidance Manual.
b. How was this proposal developed?
EPA relied in part on analyses by Clark
et al (2002a and 2002b) to develop the
CT values for ozone and chlorine
dioxide inactivation of Cryptosporidium
in today's proposal. Clark et al. (2002a)
used data from studies of ozone
inactivation of Cryptosporidium in
laboratory water to develop predictive
equations for estimating inactivation
(Rennecker et al. 1999, Li et al. 2001)
and data from studies in natural water
to validate the equations (Owens et al.
2000, Oppenheimer et al 2000). For
chlorine dioxide, Clark et al. (2002b)
employed data from Li et al. (2001) to
develop equations for predicting
inactivation, and used data from Owens
et al. (1999) and Ruffell et al. (2000) to
validate the equations.
Another step in developing the CT
values for Cryptosporidium inactivation
in today's proposal involved
consideration of the appropriate
confidence bound to apply when
analyzing the inactivation data. A
confidence bound represents a safety
margin that accounts for variability and
uncertainty in the data that underlie the
analysis. Confidence bounds are
intended to provide a high likelihood
that systems operating at a given CT
value will achieve at least the
corresponding log inactivation level in
the CT table.
Two types of confidence bounds that
are used when assessing relationships
between variables, such as disinfectant
dose (CT) and log inactivation, are
confidence in the regression and
confidence in the prediction.
Confidence in the regression accounts
for uncertainty in the regression line
(e.g., a linear relationship between
temperature and the log of the ratio of
CT to log inactivation). Confidence in
the prediction accounts for both
uncertainty in the regression line and
variability in experimental
observations—it describes the
likelihood of a single future data point
falling within a range. Bounds for
confidence in prediction are wider (i.e.,
more conservative) than those for
confidence in the regression. Depending
on the degree of confidence applied,
most points in a data set typically will
fall within the bounds for confidence in
the prediction, while a significant
fraction will fall outside the bounds for
confidence in the regression.
In developing earlier CT tables, EPA
has used bounds for confidence in the
prediction. This was a conservative
approach that was taken with
consideration of the limited inactivation
data that were available and that
reasonably ensured systems would
achieve the required inactivation level.
The November 2001 draft of the
LT2ESWTR included CT tables for
Cryptosporidium inactivation by ozone
and chlorine dioxide that were derived
using confidence in prediction (USEPA
2001g). However, based on comments
received on those draft tables, along
with further analyses described next,
EPA has revised this approach in
today's proposal.
The underlying Cryptosporidium
inactivation data used to develop the CT
tables exhibit significant variability.
This variability is due to both
experimental error and potential true
variability in the inactivation rate.
Experimental error is associated with
the assays used to measure loss of
infectivity, measurement of the
disinfectant concentration, differences
in technique among researchers, and
other factors. True variability in the
inactivation rate would be associated
with variability in resistance to the
disinfectant between different
populations of oocysts and variability in
the effect of water matrix on the
inactivation process.
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47711
In considering the appropriate
confidence bounds to use for developing
the CT tables in today's proposal, EPA
was primarily concerned with
accounting for uncertainty in the
regression and for true variability in the
inactivation rate. Variability associated
with experimental error was a lessor
concern, as the purpose of the CT tables
is to ensure a given level of inactivation
and not predict the measured result of
an individual experiment.
Because confidence in the prediction
accounts for all variability in the data
sets (both true variability and
experimental error), it may provide a
higher margin of safety than is
necessary. Nevertheless, in other
disinfection applications, the use of
confidence in the prediction may be
appropriate, given limited data sets and
uncertainty in the source of the
variability. However, the high doses of
ozone and chlorine dioxide that are
needed to inactivate Cryptosporidium
create an offsetting concern with the
formation of DBFs (e.g., bromate and
chlorite). In consideration of these
factors and the statutory provision for
balancing risks among contaminants,
EPA attempted to exclude experimental
error from the confidence bound when
developing the CT tables in today's
proposal (i.e., used a less conservative
approach than confidence in the
prediction).
In order to select confidence bounds
reflecting potential true variability
between different oocyst populations
(lots) but not variability due to
measurement and experimental
imprecision, it was necessary to
estimate the relative contributions of
these variance components. This was
done by first separating inactivation
data points into groups having the same
Cryptosporidium oocyst lot and
experimental conditions (e.g., water
matrix, pH, temperature). Next, the
variance within each group was
determined. It was assumed that this
within-group variance could be
attributed entirely to experimental error,
as neither of the factors expected to
account for true variability in the
inactivation rate (i.e., oocyst lot or water
matrix) changed within a group. Finally,
comparing the average within-group
variance to the total variance in a data
set provided an indication of the
fraction of total variance that was due to
experimental error (see Sivaganesan
2003 and Messner 2003 for details).
In carrying out this analysis on the Li
et a], (2001) and Rennecker et al (1999)
data sets for ozone inactivation of
Cryptosporidium, EPA estimated that
87.5% of the total variance could be
attributed to experimental error
(Sivaganesan 2003). A similar analysis
done by Najm et al (2002) on the
Oppenheimer et al. (2000) data set for
ozone produced an estimate of 89% of
the total variance due to experimental
error. For chlorine dioxide inactivation
of Cryptosporidium, EPA estimated that
62% of the total variance in the Li et al.
(2001) and Ruffle et al (1999) data sets
could be attributed to experimental
error (Messner 2003). The different
fractions attributed to experimental
error between the chlorine dioxide and
ozone data sets presumably relates to
the use of different experimental
techniques (e.g., infectivity assays).
EPA employed estimates of the
fraction of variance not attributable to
experimental error (12.5% for ozone and
38% for chlorine dioxide) in a modified
form of the equation used to calculate a
bound for confidence in prediction
(Messner 2003). These were applied to
the regression equations developed by
Clark et al (2002a and 2002b) in order
to estimate CT values for an upper 90%
confidence bound (Sivaganesan 2003,
Messner 2003). These are the CT values
shown in Tables IV-19 and IV-20 for
ozone and chlorine dioxide,
respectively.
Since the available data are not
sufficient to support the CT calculation
for an inactivation level greater than 3
log, the use of Tables IV-19 and IV-20
is limited to inactivation less than or
equal to 3 log. In addition, the
temperature limitation for these tables is
1 to 25 °C. If the water temperature is
higher than 25 °C, temperature should .
be set to 25 °C for the log inactivation
calcuiation.
EPA recognizes that inactivation rates
may be sensitive to water quality and
operational conditions in the plant. To
reflect this potential, systems are given
the option to perform a site specific
inactivation study to determine CT
requirements. The State must approve
the protocols or other information used
to derive alternative CT values.
However, EPA has provided guidance
for systems in making such
demonstrations in the Toolbox
Guidance Manual.
During meetings of the Stage 2 M-DBP
Advisory Committee, CT values were
used in the model for impact analysis of
different regulatory options (the model
Surface Water Analytical Tool (SWAT),
as described in Economic Analysis for
the LT2ESWTR, USEPA 2003a). Those
preliminary CT values were based on a
subset of the data from the Li et al
(2001) study with laboratory waters and
were adjusted with a factor to match the
mean CT values derived from the
Oppenheimer et al (2000) study with
natural waters. In comparison, the CT
values in today's proposal are higher.
However, the current CT values are
based on larger data sets and more
comprehensive analyses. Consequently,
they provide more confidence in
estimates of Cryptosporidium log
inactivation than the preliminary
estimates used in earlier SWAT
modeling. EPA has subsequently re-run
analyses for LT2ESWTR impact
assessments with the updated CT values
(USEPA 2003a).
c. Request for comments. EPA
requests comment on the proposed
approach to awarding credit for
inactivation of Cryptosporidium by
chlorine dioxide and ozone, including
the following specific issues:
• Determination of CT and the
confidence bounds used for estimating
log inactivation of Cryptosporidium;
• The ability of systems to apply
these CT tables in consideration of the
MCLs for bromate and chlorite; and
• Any additional data that may be
used to confirm or refine the proposed
CT tables.
15. Ultra violet Light
a. What is EPA proposing today? EPA
is proposing criteria for awarding credit
to ultraviolet (UV) disinfection
processes for inactivation of
Cryptosporidium, Giardia lamblia, and
viruses. The inactivation credit a system
can receive for each target pathogen is
based on the UV dose applied by the
system in relation to the UV dose
requirements in this section (see Table
IV-21).
To receive UV disinfection credit, a
system must demonstrate a UV dose
using the results of a UV reactor
validation test and ongoing monitoring.
The reactor validation test establishes
the operating conditions under which a
reactor can deliver a required UV dose.
Monitoring is used to demonstrate that
the system maintains these validated
operating conditions during routine use.
UV dose (fluence) is defined as the
product of the UV intensity over a
surface area {fluence rate) and the
exposure time. In practice, UV reactors
deliver a distribution of doses due to
variation in light intensity and flow
path as particles pass through the
reactor. However, for the purpose of
determining compliance with the dose
requirements in Table IV-21, UV dose
must be assigned to a reactor based on
the degree of inactivation of a
microorganism achieved during a
reactor validation test. This assigned UV
dose is determined through comparing
the reactor validation test results with a
known dose-response relationship for
the test microorganism. The State may
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designate an alternative basis for
awarding UV disinfection credit.
EPA is developing the UV
Disinfection Guidance Manual (USEPA
2003d) to assist systems and States with
implementing UV disinfection,
including validation testing of UV
reactors. This guidance is available in
draft in the docket for today's proposal
(h ftp ://www. epa.gov/edocket/).
UV Dose Tables
Table IV-21 shows the UV doses that
systems must apply to receive credit for
up to 3 log inactivation of
Cryptosporidium and Giardia lamblia
and up to 4 log inactivation of viruses.
These dose values are for UV light at a
wavelength of 254 nm as delivered by
a low pressure mercury vapor lamp.
However, the dose values can be
applied to other UV lamp types (e.g.,
medium pressure mercury vapor lamps)
through reactor validation testing, such
as is described in the draft UV
Disinfection Guidance Manual (USEPA
2003d). In addition, the dose values in
Table IV-21 are intended for post-filter
application of UV in filtration plants
and for systems that meet the filtration
avoidance criteria in 40 CFR 141.71.
BILLING CODE 656&-50-P
Table IV-21.- UV Dose Requirements for Cryptosporidium, Giardia lamblia, and
Virus Inactivation Credit
Log credit
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
Cryptosporidium
UV dose (mJ/cm2)
1.6
2.5
3.9
5.8
8.5
12
NA
NA
Giardia lamblia
UV dose (m J/cm2)
1.5
2.1
3.0
5.2
7.7
11
NA
NA
Virus
UV dose (mJ/cm2)
39
58
79
100
121
143
163
186
BILLING CODE 6560-50-C
Reactor Validation Testing
For a system to receive UV
disinfection credit, the UV reactor type
used by the system must undergo
validation testing to demonstrate the
operating conditions under which the
reactor can deliver the required UV
dose. Unless the State approves an
alternative approach, this testing must
involve the following: (1) Full scale
testing of a reactor that conforms
uniformly to the UV reactors used by
the system and (2) inactivation of a test
microorganism whose dose response
characteristics have been quantified
with a low pressure mercury vapor
lamp.
Validation testing must determine a
set of operating conditions that can be
monitored by the system to ensure that
the required UV dose is delivered under
the range of operating conditions
applicable to the system. At a minimum,
these operating conditions must include
flow rate, UV intensity as measured by
a UV sensor, and UV lamp status. The
validated operating conditions
determined by testing must account for
the following factors: (1) UV absorbance
of the water, (2) lamp fouling and aging,
(3) measurement uncertainty of on-line
sensors, (4) dose distributions arising
from the velocity profiles through the
reactor, (5) failure of UV lamps or other
critical system components, and (6)
inlet and outlet piping or channel
configurations of the UV reactor. In the
draft UV Disinfection Guidance Manual
(USEPA 2003d), EPA describes testing
protocols for reactor validation that are
intended to meet these criteria.
Reactor Monitoring
Systems must monitor for parameters
necessary to demonstrate compliance
with the operating conditions that were
validated for the required UV dose. At
a minimum systems must monitor for
UV intensity as measured by a UV
sensor, flow rate, and lamp outage. As
part of this, systems must check the
calibration of UV sensors and recalibrate
in accordance with a protocol approved
by the State.
b. How was this proposal developed?
UV disinfection is a physical process
relying on the transference of
electromagnetic energy from a source
(lamp) to an organism's cellular material
(USEPA 1986). In the Stage 2 M-DBP
Agreement in Principle, the Advisory
Committee recommended that EPA
determine the UV doses needed to
achieve up to 3 log inactivation of
Giardia lamblia and Cryptosporidium
and up to 4 log inactivation of viruses.
The Agreement further recommends
that EPA develop standards to
determine if UV systems are acceptable
for compliance with drinking water
disinfection requirements, including (1)
a validation protocol for drinking water
applications of UV technology and (2)
on-site monitoring requirements to
ensure ongoing compliance with UV
dose tables. EPA also agreed to develop
a UV guidance manual to facilitate
design and operation of UV
installations. Today's proposal and
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47713
accompanying guidance for UV are
consistent with the Agreement.
UV Dose Tables
The UV dose values in Table IV-21
are based on meta-analyses of UV
inactivation studies with
Cryptosporidium parvum, Giardia
lamblia, Giardia muris, and adenovirus
(Qian et al, 2003, USEPA 2003d).
Proposed UV doses for inactivation of
viruses are based on the dose-response
of adenovirus because, among viruses
that have been studied, it appears to be
the most UV resistant and is a
widespread waterborne pathogen
(health effects of adenovirus are
described in Embrey 1999).
The data supporting the dose values
in Table IV-21 are from.bench-scale
studies using low pressure mercury
vapor lamps. These data were chosen
because the experimental conditions
allow UV dose to be accurately
quantified. Low pressure lamps emit
light primarily at a single wavelength
(254 nm) within the germicidal range of
200-300 nm. However, as noted earlier,
these dose tables can be applied to
reactors with other lamp types through
reactor challenge testing, as described in
the draft guidance manual. Bench scale
studies are preferable for determining
pathogen dose-response characteristics,
due to the uniform dose distribution.
The data sets and statistical
evaluation that were used to develop the
UV dose table for Cryptosporidium,
Giardia lamblia, and viruses are
described in the draft UV Disinfection
Guidance Manual (USEPA 2003d) and
Qianef al. 2003.
Reactor Validation Testing
Today's proposal requires testing of
full-scale UV reactors because of the
difficulty in predicting reactor
disinfection performance based on
modeled results or on the results of
testing at a reduced scale. All flow-
through UV reactors deliver a
distribution of doses due to variation in
light intensity within the reactor and the
different flow paths of particles passing
through the reactor. Moreover, the
reactor dose distribution varies
temporally due to processes like lamp
aging and fouling, changes in UV
absorbance of the water, and
fluctuations in flow rate. Consequently,
it is more reliable to evaluate reactor
performance through a full scale test
under conditions that can be
characterized as "worst case" for a given
application. Such conditions include
maximum and minimum flow rate and
reduced light intensity within the
reactor that accounts for lamp aging,
fouling, and UV absorbance of the
water. Protocols for reactor validation
testing are presented in the draft UV
guidance manual.
c. Request for comment. The Agency
requests comment on whether the
criteria described in this section for
awarding treatment credit for UV
disinfection are appropriate, and
whether additional criteria, or more
specific criteria, should be included.
16. Individual Filter Performance
a. What is EPA proposing today? EPA
is proposing an additional 1.0 log
Cryptosporidium treatment credit for
systems that achieve individual filter
performance consistent with the goals
established for the Partnership for Safe
Water Phase IV in August 2001 (AWWA
etal. 2001). Specifically, systems must
demonstrate ongoing compliance with
the following turbidity criteria, based on
continuous monitoring of turbidity for
each individual filter as required under
40 CFR 141.174 or 141.560, as
applicable:
(1) Filtered water turbidity less than 0.1
NTU in at least 95% of the maximum daily
values recorded at each filter in each month,
excluding the 15 minute period following
backwashes, and
(2) No individual filter with a measured
turbidity level of greater than 0.3 NTU in two
consecutive measurements taken 15 minutes
apart.
Note that today's proposal does not
include a required peer review step as
a condition for receiving additional
credit. Rather, EPA is proposing to
award additional credit to systems that
meet the performance goals of a peer
review program (Phase IV). Systems that
receive the 1 log additional treatment
credit for individual filter performance,
as described in this section, cannot also
receive an additional 0.5 log additional
credit for lower finished water turbidity
as described in section IV.C.8.
b. How was this proposal developed?
In the Stage 2 M-DBP Agreement in
Principle, the Advisory Committee
recommended a peer review program as
a microbial toolbox component that
should receive a 1.0 log
Cryptosporidium treatment credit. The
Committee specified Phase IV of the
Partnership for Safe Water (Partnership)
as an example of the type of peer review
program where a 1.0 log credit would be
appropriate.
The Partnership is a voluntary
cooperative program involving EPA, the
Association of Metropolitan Water
Agencies (AMWA), the American Water
Works Association (AWWA), the
National Association of Water
Companies (NAWC), the Association of
State Drinking Water Administrators
(ASDWA), the American Water Works
Association Research Foundation
(AWWARFJ, and surface water utilities
throughout the United States. The intent
of the Partnership is to increase
protection against microbial
contaminants by optimizing treatment
plant performance.
At the time of the Advisory
Committee recommendation, Phase IV
was under development by the
Partnership. It was to be based on
Composite Correction Program (CCP)
(USEPA 1991) procedures and
performance goals, and was to be
awarded based on an on-site evaluation
by a third-party team. The performance
goals for Phase IV were such that, over
a year, each sedimentation basin and
each filter would need to produce
specified turbidity levels based on the
maximum of all the values recorded
during the day. Sedimentation
performance goals were set at 2.0 NTU
if the raw water was greater than 10
NTU on an annual basis and 1.0 NTU
if the raw water was less than 10 NTU.
Each filter was to meet 0.1 NTU 95% of
the time except for the 15 minute period
following placing the filter in operation.
In addition, filters were expected to
have maximum turbidity of 0.3 NTU
and return to less than 0.1 NTU within
15 minutes of the filter being placed in
service.
The primary purpose of the on-site
evaluation was to confirm that the
performance of the plant was consistent
with Phase IV performance goals and
that the system had the administrative
support and operational capabilities to
sustain the performance long-term. The
on-site evaluation in Phase IV also
allowed utilities that could not meet the
desired performance goals to
demonstrate to the third-party that they
had achieved the highest level of
performance given their unique raw
water quality.
After the signing of the Stage 2 M-
DBP Agreement in Principle in
September 2000, the Partnership
decided to eliminate the on-site third-
party evaluation as a component of
Phase IV. Instead, the requirement for
Phase IV is for the water system to
complete an application package that
will be reviewed by trained utility
volunteers. Included in the application
package is an Optimization Assessment
Spreadsheet in which the system enters
water quality and treatment data to
demonstrate that Phase IV performance
levels have been achieved. The
application also requires narratives
related to administrative support and
operational capabilities to sustain
performance long-term.
Today's proposal is consistent with
the performance goals of Phase IV.
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Rather than require systems to complete
an application package with historical
data and narratives, the LT2ESWTR
requires systems to demonstrate to the
State that they meet the individual filter
performance goals of Phase IV on an
ongoing basis to receive the 1.0 log
additional Cryptosporidium treatment
credit. EPA is not requiring systems to
demonstrate that they meet
sedimentation performance goals of
Phase W. While EPA recognizes that
settled water turbidity is an important
operational performance measure for a
plant, the Agency does not have data
directly relating it to finished water
quality and pathogen risk.
The November 2001 pre-proposal
draft of the LT2ESWTR described a
potential 1.0 log credit for systems that
achieved individual filter effluent (IFE)
turbidity below 0.15 NTU in 95 percent
of samples [USEPA 2001g). The Science
Advisory Board (SAB) subsequently
reviewed this credit and supporting data
on the relationship between filter
effluent turbidity and Cryptosporidium
removal efficiency (described in section
IV.G.8). In written comments from a
December 2001 meeting of the Drinking
Water Committee, an SAB panel
recommended only a 0.5 log credit for
95th percentile IFE turbidity below 0.15
NTU.
To address this recommendation from
the SAB, EPA is proposing that systems
meet the individual filter performance
criteria of Phase IV of the Partnership in
order to be eligible for a 1.0 log
additional Cryptosporidium treatment
credit. This proposed approach
responds to the concerns raised by the
SAB because the Phase IV criteria are
more stringent than those in the 2001
pre-proposal draft of the LT2ESWTR.
For example, today's proposal sets a
maximum limit on individual filter
effluent turbidity of 0.3 NTU, whereas
no such upper limit was described in
the 2001 pre-proposal draft.
In summary, EPA has concluded that
it is appropriate to award additional
Cryptosporidium treatment credit for
systems meeting stringent individual
filter performance standards. Modestly
elevated turbidity from a single filter
may not significantly impact combined
filter effluent turbidity levels, which are
regulated under IESWTR and
LT1ESWTR, but may indicate a
substantial reduction in the overall
pathogen removal efficiency of the
filtration process. Consequently,
systems that continually achieve very
low turbidity in each individual filter
are likely to provide a significantly more
effective microbial barrier. EPA expects
that systems that select this toolbox
option will have achieved a high level
of treatment process optimization and
process control, and will have both a
history of consistent performance over a
range of raw water quality conditions
and the capability and resources to
maintain this performance long-term.
c. Request for comment. The Agency
invites comment on the following issues
related to the proposed credit for
individual filter performance.
• Are there different or additional
performance measures that a utility
should be required to meet for the 1 log
additional credit?
• Are there existing peer review
programs for which treatment credit
should be awarded under the
LT2ESWTR? If so, what role should
primacy agencies play in establishing
and managing any such peer review
program?
• The individual filter effluent
turbidity criterion of 0.1 NTU is
proposed because it is consistent with
Phase IV Partnership standards, as
based on CCP goals. However, with
allowable rounding, turbidity levels less
than 0.15 NTU are in compliance with
a standard of 0.1. Consequently, EPA
requests comment on whether 0.15 NTU
should be the standard for individual
filter performance credit, as this would
be consistent with the standard of 0.15
NTU that is proposed for combined
filter performance credit in section
IV.C.8.
17. Other Demonstration of Performance
a. What is EPA proposing today? The
purpose of the "demonstration of
performance" toolbox component is to
allow a system to demonstrate that a
plant, or a unit process within a plant,
should receive a higher
Cryptosporidium treatment credit than
is presumptively awarded under the
LT2ESWTR. For example, as described
in section IV.A, plants using
conventional treatment receive a
presumptive 3 log credit towards the
Cryptosporidium treatment
requirements in Bins 2-4 of the
LT2ESWTR. This credit is based on a
determination by EPA that conventional
treatment plants achieve an average
Cryptosporidium removal of 3 log when
in compliance with the IESWTR or
LT1ESWTR. However, EPA recognizes
that some conventional treatment plants
may achieve average Cryptosporidium
removal efficiencies greater than 3 log.
Similarly, some systems may achieve
Cryptosporidium reductions with
certain toolbox components that are
greater than the presumptive credits
awarded under the LT2ESWTR, as
described in this section (IV.C).
Where a system can demonstrate that
a plant, or a unit process within a plant,
achieves a Cryptosporidium reduction
efficiency greater than the presumptive
credit specified in the LT2ESWTR, it
may be appropriate for the system to
receive a higher Cryptosporidium
treatment credit. Today's proposal does
not include specific protocols for
systems to make such a demonstration,
due to the potentially complex and site
specific nature of the testing that would
be required. Rather, today's proposal
allows a State to award a higher level of
Cryptosporidium treatment credit to a
system where the State determines,
based on site-specific testing with a
State-approved protocol, that a
treatment plant or a unit process within
a plant reliably achieves a higher level
of Cryptosporidium removal on a
continuing basis. Also, States may
award a lower level of Cryptosporidium
treatment credit to a system where a
State determines, based on site specific
information, that a plant or a unit
process within a plant achieves a
Cryptosporidium removal efficiency less
than a presumptive credit specified in
the LT2ESWTR.
Systems receiving additional
Cryptosporidium treatment credit
through a demonstration of performance
may be required by the State to report
operational data on a monthly basis to
establish that conditions under which
demonstration of performance credit
was awarded are maintained during
routine operation. The Toolbox
Guidance Manual (USEPA 2003f) will
describe potential approaches to
demonstration of performance testing.
This guidance is available in draft in the
docket for today's proposal (http://
www.epa.gov/edocket/).
Note that as described in section IV.C,
today's proposal allows treatment plants
to achieve additional Cryptosporidium
treatment credit through meeting the
design and/or operational criteria of
microbial toolbox components, such as
combined and individual filter
performance, presedimentation, bank
filtration, two-stage softening, secondary
filtration, etc. Plants that receive
additional Cryptosporidium treatment
credit through a demonstration of
performance are not also eligible for the
presumptive credit associated with
microbial toolbox components if the
additional removal due to the toolbox
component is captured in the
demonstration of performance credit.
For example, if a plant receives a
demonstration of performance credit
based on removal of Cryptosporidium or
an indicator while operating under
conditions of lower finished water
turbidity, the plant may not also receive
additional presumptive credit for lower
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47715
finished water turbidity toolbox
components.
This demonstration of performance
credit does not apply to the use of
chlorine dioxide, ozone, or UV light,
because today's proposal includes
specific provisions allowing the State to
modify the standards for awarding
disinfection credit to these technologies.
As described in section IV.C.14, States
can approve site-specific CT values for
inactivation of Cryptosporidium by
chlorine dioxide and ozone; as
described in section IV.C.15, States can
approve an alternative approach for
validating the performance of UV
reactors.
b. How was this proposal developed?
The Stage 2 M-DBP Agreement in
Principle recommends demonstration of
performance as a process for systems to
receive Cryptosporidium treatment
credit higher than the presumptive
credit for many microbial toolbox
components, as well as credit for
technologies not listed in the toolbox.
EPA is aware that there may be plants
where particular unit processes, or
combinations of unit processes, achieve
greater Cryptosporidium removal than
the presumptive credit awarded under
the LT2ESWTR. In addition, the Agency
would like to allow for the use of
Cryptosporidium treatment processes
not addressed in the LT2ESWTR, where
such processes can demonstrate a
reliable specific !og removal. Due to
these factors, EPA is proposing a
demonstration of performance
component in the microbial toolbox,
consistent with the Advisory Committee
recommen dation.
The Agreement in Principle makes no
recommendations for how a
demonstration of performance should be
conducted. It is generally not practical
for systems to directly quantify high log
removal of Cryptosporidium in
treatment plants because of the
relatively low occurrence of
Cryptosporidium in many raw water
sources and limitations with analytical
methods. Consequently, if systems are
to demonstrate the performance of full
scale plants in removing
Cryptosporidium, this typically will
require the use of indicators, where the
removal of the indicator has been
correlated with the removal of
Cryptosporidium. As described
previously, a number of studies have
shown that aerobic spores are an
indicator of Cryptosporidium removal
by sedimentation and filtration (Dugan
et al 2001, Emelko et al 1999 and 2000,
Yates et al 1998, Mazounie et al. 2000).
The nature of demonstration of
performance testing that will be
appropriate at a given facility will
depend on site specific factors, such as
water quality, the particular process(es)
being evaluated, resources and '
infrastructure, and the discretion of the
State. Consequently, EPA is not
proposing specific criteria for
demonstration of performance testing.
Instead, systems must develop a testing
protocol that is approved by the State,
including any requirements for ongoing
reporting if demonstration of
performance credit is approved. EPA
has developed a draft document,
Toolbox Guidance Manual (USEPA
2003f), that is available with today's
proposal and provides guidance on
demonstration of performance testing.
c. Request for comment. The Agency
requests comment on today's proposal
for systems to demonstrate higher
Cryptosporidium removal levels. EPA
specifically requests comment on the
following issues:
• Approaches that should be
considered or excluded for
demonstration of performance testing;
• Whether EPA should propose
minimum elements that demonstration
of performance testing must include;
• Whether a factor of safety should be
applied to the results of demonstration
of performance testing to account for
potential differences in removal of an
indicator and removal of
Cryptosporidium, or uncertainty in the
application of pilot-scale results to full-
scale plants;
• Whether or under what conditions
a demonstration of performance credit
should be allowed for a unit process
within a plant—a potential concern is
that certain unit processes, such as a
sedimentation basin, can be operated in
a manner that will increase removal in
the unit process but decrease removal in
subsequent treatment processes and,
therefore, lead to no overall increase in
removal through the plant. An approach
to address this concern is to limit
demonstration of performance credit to
removal demonstrated across the entire
treatment plant.
D. Disinfection Benchmarks for Giardia
lamblia and Viruses
1. What Is EPA Proposing Today?
EPA proposes to establish the
disinfection benchmark under the
LT2ESWTR as a procedure to ensure
that systems maintain protection against
microbial pathogens as they implement
the Stage 2 M-DBP rules (i.e., Stage 2
DBPR and LT2ESWTR). The
disinfection benchmark serves as a tool
for systems and States to evaluate the
impact on microbial risk of proposed
changes in disinfection practice. EPA
established the disinfection benchmark
under the IESWTR and LTlESWTR for
the Stage 1 M-DBP rules, as
recommended by the Stage 1 M-DBP
Advisory Committee. Today's proposal
extends disinfection benchmark
requirements to apply to the Stage 2 M-
DBP rules.
Under the proposed LT2ESWTR, the
disinfection benchmark procedure
involves a system charting levels of
Giardia lambJia and virus inactivation
at least once per week over a period of
at least one year. This creates a profile
of inactivation performance that the
System must use to determine a baseline
or benchmark of inactivation against
which proposed changes in disinfection
practice can be measured. Only certain
systems are required to develop profiles
and keep them on file for State review
during sanitary surveys. When those
systems that are required to develop a
profile plan a significant change in
disinfection practice (defined later in
this section), they must submit the
profile and an analysis of how the
proposed change will affect the current
disinfection benchmark to the State for
review.
Systems that developed disinfection
profiles under the IESWTR or
LTlESWTR and have not made
significant changes in their disinfection
practice or changed sources are not
required to collect additional
operational data to create disinfection
profiles under the LT2ESWTR. Systems
that produced a disinfection profile for
Giardia lamblia but not viruses under
the IESWTR or LTlESWTR may be
required to develop a profile for viruses
under the LT2ESWTR. Where a
previously developed Giardia lamblia
profile is acceptable, systems may
develop a virus profile using the same
operational data (i.e., CT values) on
which the Giardia lamblia profile is
based. Spreadsheets developed by EPA
and States automatically calculate
Giardia lamblia and virus profiles using
the same operational data. EPA believes
that virus profiling is necessary because
many of the disinfection processes that
systems will select to comply with the
Stage 2 DBPR and LT2ESWTR (e.g.,
chloramines, UV, MF/UF) are relatively
less effective against viruses than
Giardia lamblia in comparison to free
chlorine.
The disinfection benchmark
provisions contain three major
components: (a) Applicability
requirements and schedule, (b)
characterization of disinfection practice,
and (c) State review of proposed
changes in disinfection practice. Each of
these components is discussed in the
following paragraphs.
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Federal Register/Vol. 68, No. 154/Monday. August 11, 2003/Proposed Rules
a. Applicability and schedule.
Proposed disinfection profiling and
benchmarking requirements apply to
surface water systems only. Systems
serving only ground water are not
subject to the requirements of the
LT2ESWTR. The determination of
whether a surface water system is
required to develop a disinfection
profile is based on whether DBF levels
(TTHM or HAA5) exceed specified
values, described later in this section,
and whether a system is required to
monitor for Cryptosporidium. These
criteria trigger profiling because they
identify systems that may be required to
make treatment changes under the Stage
2 DBPR or LT2ESWTR. Note that it is
not practical to wait until a system has
completed Cryptosporidium monitoring
to identify which systems should
prepare a disinfection profile. A
completed disinfection profile should
be available at the point when a system
is classified in a treatment bin and must
begin developing plans to comply with
any additional treatment requirements.
Unless the system developed a
disinfection profile under the IESWTR
or LTlESWTR, all systems required to
monitor for Cryptosporidium must
develop Giardia lamblia and virus
disinfection profiles under the
LT2ESWTR. This includes all surface
water systems except (1) systems that
provide 5.5 log total treatment for
Cryptosporidium, equivalent to meeting
the treatment requirements of Bin 4 and
(2) small systems (<10,000 people
served) that do not exceed the E. coll
trigger (see section 1V.A for details).
Systems not required to monitor for
Cryptosporidium as a result of providing
5.5 log of treatment are not required to
prepare disinfection profiles. However,
small systems that do not exceed the E.
coli trigger are required to prepare
Giardia lamblia and virus disinfection
profiles if one of the following criteria
apply, based on DBF levels in their
distribution systems:
(i)* TTHM levels in the distribution
system, based on samples collected for
compliance with the Stage 1 DBPR, are
at least 80% of the MCL (0.064 mg/L) at
any Stage 1 DBPR sampling point based
on a locational running annual average
(LRAA).
(2)* HAA5 levels in the distribution
system, based on the samples collected
for compliance with the Stage 1 DBPR,
are at least 80% of the MCL (0.048 mg/
L) at any Stage 1 DBPR sampling point
based on an LRAA.
*These criteria only apply to systems
that are required to comply with the
DBP rules, i.e., community and non-
transient non-community systems.
Table IV-22 presents a summary
schedule of the required deadlines for
disinfection profiling activities,
categorized by system size and whether
a small system is required to monitor for
Cryptosporidium. The deadlines are
based on the expectation that a system
should have a disinfection profile at the
time the system is classified in a
Cryptosporidium treatment bin under
LT2ESWTR and/or has determined the
need to make treatment changes for the
Stage 2 DBPR. Systems have three years
from this date, with a possible two year
extension for capital improvements if
granted by the State, within which to
complete their evaluation, design, and
implementation of treatment changes to
meet the requirements of the
LT2ESWTR and the Stage 2 DBPR.
TABLE IV-22.—SCHEDULE OF IMPLEMENTATION DEADLINES RELATED TO DISINFECTION PROFILING
Activity
.. .
Complete 1 year oft. cort monitoring "•"""; ', 'j"""t'.'t""~t * «
Determine whether required to profile oasea on uer ieveis anu numy oimo
Complete disinfection profiling based on at least one year's data5 ••-_
Systems serv-
ing >1 0,000
people2
NA
NA
24
30
36
Systems serving <10,000 peo-
ple
Required to
monitor for
Cryptosporidium
42
NA
54
60
66
Not required to
monitor for
Cryptosporidi-
um2 36
42
42
42
NA
54
"-ing Bin 4 treatment requirements) are not required to de-
10,000 people are not required to monitor for Cryptosporidium if mean E coff levels are less than 10/100 mL for
'W> or less than 50/100 mL for systems using flowing stream sources.
^ ?ear!oadreata?hCeefendleof which compliance with the LT2ESWTR and Stage 2 DBPR is re-
required to conduct profiling unless TTHM or HAAS exceeds trigger values of 80% of MCL at any sampling point based on LRAA.
As described in the next section,
systems can meet profiling requirements
under the proposed LT2ESWTR using
previously collected data (i.e.,
grandfathered data). Use of
grandfathered data is allowed if the
system has not made a significant
change in disinfection practice or
changed sources since the data were
collected. This will permit most systems
that prepared a disinfection profile
under the IESWTR or the LTlESWTR to
avoid collecting any new operational
data to develop profiles under the
LT2ESWTR.
The locational running annual
average (LRAA) of TTHM and HAAS
levels used by small systems that do not
monitor for Cryptosporidium to
determine whether profiling is required
must be based on one year of DBP data
collected during the period following
promulgation of the LT2ESWTR, or as
determined by the State. By the date
indicated in Table IV-22, these systems
must report to the State on their DBP
LRAAs and whether the disinfection
profiling requirements apply. If either
DBP LRAA meets the criteria specified
previously, the system must begin
disinfection profiling by the date
proposed in Table IV-22.
b. Developing the disinfection profile
and benchmark. Under the LT2ESWTR,
a disinfection profile consists of a
compilation of Giardia lamblia and
virus log inactivation levels computed
at least weekly over a period of at least
one year, as based on operational and
water quality data (disinfectant residual
concentration (s), contact time(s),
temperature (s), and, where necessary,
pH). The system may create the profile
by conducting new weekly (or more
frequent) monitoring and/or by using
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47717
grandfathered data. A system that
created a Giardia lamblia disinfection
profile under the IESWTR or
LT1ESWTR may use.the operational
data collected for the Giardia lamblia
profile to create a virus disinfection
profile.
Grandfathered data are those
operational data that a system has
previously collected at a treatment plant
during the course of normal operation.
Those systems that have all the
necessary information to determine
profiles using existing operational data
collected prior to the date when the
system is required to begin profiling
may use these data in developing
profiles. However, grandfathered data
must be substantially equivalent to
operational data that would be collected
under this rule. These data must be
representative of inactivation through
the entire treatment plant and not just
of certain treatment segments.
To develop disinfection profiles
under this rule, systems are required to
exercise one of the following three
options:
Option 1—Systems conduct
monitoring at least once per week
following the process described later in
this section.
Option 2—Systems that conduct
monitoring under this rule, as described
under Option 1, can also use one or two
years of acceptable grandfathered data,
in addition to one year of new
operational data, in developing the
disinfection profile.
Option 3—Systems that have at least
one year of acceptable existing
operational data are not required to
conduct new monitoring to develop the
disinfection profile under this rule.
Instead, they can use a disinfection
profile based oh one to three years of
grandfathered data.
Process to be followed by PWS for
developing the disinfection profile:
—Measure disinfectant residual
concentration (C, in mg/L) before or at
the first customer and just prior to
each additional point of disinfectant
addition, whether with the same or a
different disinfectant.
—Determine contact time (T, in
minutes} for each residual
disinfectant monitoring point during
peak flow conditions. T could be
based on either a tracer study or
assumptions based on contactor basin
geometry and baffling. However,
systems must use the same method for
both grandfathered data and new data.
—Measure water temperature (°C) (for
disinfectants other than UV).
—Measure pH (for chlorine only).
To determine the weekly log
inactivation, the system must convert
operational data from one day each
week to the corresponding log
inactivation values for Giardia lamblia
and viruses. The procedure for Giardia
lamblia is as follows:
—Determine CTca1c for each disinfection
segment.
—Determine CT99.9 0*.e., 3 log
inactivation) from tables in the SWTR
(40 CFR 141.74) using temperature
(and pH for chlorine) for each
disinfection segment. States can allow
an alternate calculation procedure
(e.g., use of a spreadsheet).
—For each segment, log inactivation =
(CTcalc/CT99.9)x3.0.
—Sum the log inactivation values for
each segment to get the log
inactivation for the day (or week).
For calculating the virus log
inactivation, systems should use the
procedures approved by States under
the IESWTR or LT1ESWTR. Log
inactivation benchmark is calculated as
follows:
—Determine the calendar month with
the lowest log inactivation.
—The lowest month becomes the
critical period for that year.
—If acceptable data from multiple years
are available, the average of critical
periods for each year becomes the
benchmark.
—If only one year of data is available,
the critical period for that year is the
benchmark.
c. State review. If a system that is
required to produce a disinfection
profile proposes to make a significant
change in disinfection practice, it must
calculate Giardia lamblia and virus
inactivation benchmarks and must
notify the State before implementing
such a change. Significant changes in
disinfection practice are defined as (1)
moving the point of disinfection (this is
not intended to include 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. When
notifying the State, the system must
provide a description of the proposed
change, the disinfection profiles and
inactivation benchmarks for Giardia
lamblia and viruses, and an analysis of
how the proposed change will affect the
current inactivation benchmarks. In
addition, the system should have
disinfection profiles and, if applicable,
inactivation benchmarking
documentation, available for the State to
review as part of its periodic sanitary
survey.
EPA developed for the IESWTR, with
stakeholder input, the Disinfection
Profiling and Benchmarking Guidance
Manual (USEPA 1999d). This manual
provides guidance to systems and States
on the development of disinfection
profiles, identification and evaluation of
significant changes in disinfection
practices, and considerations for setting
an alternative benchmark. If necessary,
EPA will produce an addendum to
reflect changes in the profiling and
benchmarking requirements necessary
to comply with LT2ESWTR.
2. How Was This Proposal Developed?
A fundamental premise in the
development of the M-DBP rules is the
concept of balancing risks between
DBFs and microbial pathogens.
Disinfection profiling and
benchmarking were established under
the IESWTR and LTlESWTR, based on
a recommendation by the Stage 1 M-
DBP Federal Advisory Committee, to
ensure that systems maintained
adequate control of pathogen risk as
they reduced risk from DBPs. Today's
proposal would extend disinfection
benchmarking requirements to the
LT2ESWTR.
EPA believes this extension is
necessary because some systems will
make significant changes in their
current disinfection practice to meet
more stringent limits on TTHM and
HAAS levels under the Stage 2 DBPR
and additional Cryptosporidium
treatment requirements under the
LT2ESWTR. In order to ensure that
these systems continue to provide
adequate protection against the full
spectrum of microbial pathogens, it is
appropriate for systems and States to
evaluate the effects of such treatment
changes on microbial drinking water
quality. The disinfection benchmark
serves as a tool for making such
evaluations.
EPA projects that to comply with the
Stage 2 DBPR, systems will make
changes to their disinfection practice,
including switching from free chlorine
to chloramines and, to a lesser extent,
installing technologies like ozone,
membranes, and UV. Similarly, to
provide additional treatment for
Cryptosporidium, some systems will
install technologies like UV, ozone, and
micro filtration. While these processes
are all effective disinfectants,
chloramines are a weaker disinfectant
than free chlorine for Giardia lamblia.
Ozone, UV, and membranes can provide
highly effective treatment for Giardia
lamblia, but they, as well as
chloramines, are less efficient for
treating viruses than free chlorine,
relative to their efficacy for Giardia
lamblia. Because of this, a system
switching from free chlorine to one of
these alternative disinfection
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technologies could experience a
reduction in the level of virus and/or
Giardia lamblia (for chloramines)
treatment it is achieving. Consequently,
EPA believes that systems making
significant changes in their disinfection
practice under the Stage 2 M-DBP rules
should assess the impact of these
changes with disinfection benchmarks
for Giardia lamblia and viruses.
Changes in the proposed
benchmarking requirements under the
LT2ESWTR in comparison to IESWTR
requirements include decreasing the
frequency of calculating CT values for
the disinfection profile from daily to
weekly and requiring al! systems to
prepare a profile for viruses as well as
Giardia lamblia. The proposal of a
weekly frequency for CT calculations
was made to accommodate existing
profiles from small systems, which are
required to make weekly CT
calculations for profiling under the
LTlESWTR. As described earlier, EPA
would like for systems that have
prepared a disinfection profile under
the IESWTR or LTlESWTR and have
not subsequently made significant
changes in disinfection practice to be
able to grandfather this profile for the
LT2ESWTR. Allowing weekly
calculation of CT values under the
LT2ESWTR will make this possible.
The IESWTR and LTlESWTR
required virus inactivation profiling
only for systems using ozone or
chloramine as their primary
disinfectant. However, as noted earlier,
EPA has projected that under the Stage
2 DBPR and LT2ESWTR, systems will
switch from free chlorine to disinfection
processes like chloramines, UV, ozone,
and micron'Itration. The efficiency of
these processes for virus treatment
relative to protozoa treatment is lower
in comparison to free chlorine. As a
result, a disinfection benchmark for
Giardia lamblia would not necessarily
provide an indication of the level or
adequacy of treatment for viruses.
Consequently, EPA believes it is
appropriate for systems to develop
profiles for both Giardia lamblia and
viruses. Moreover, developing a profile
for viruses involves a minimal increase
in effort and no additional data
collection for those systems that have
disinfection profiles for Giardia lamblia.
Systems will use the same calculated CT
values for viruses as would be used for
the Giardia lamblia profile.
The strategy of disinfection profiling
and benchmarking stemmed from data
provided to the Stagel M-DBP Advisory
Committee, in which the baseline of
microbial inactivation (expressed as logs
of Giardia lamblia inactivation}
demonstrated high variability.
Inactivation varied by several logs (i.e.,
orders of magnitude) on a day-to-day
basis at particular treatment plants and
by as much as tens of logs over a year
due to changes in water temperature,
flow rate, seasonal changes, pH, and
disinfectant demand. There were also
differences between years at individual
plants. To address these variations, M--
DBP stakeholders developed the
procedure of profiling a plant's
inactivation levels over a period of at
least one year, and then establishing a
benchmark of minimum inactivation as
a way to characterize disinfection
practice.
Benchmarking of inactivation levels,
an assessment of the impact of proposed
changes on the level of microbial
inactivation of Giardia lamblia and
viruses, and State review prior to
approval of substantial changes in
treatment are important steps in
avoiding conditions that present an
increase in microbial risk. In its
assessment of the microbial risk
associated with the proposed changes,
States could consider site-specific
knowledge of the watershed and
hydrologic factors as well as variability,
flexibility and reliability of treatment to
ensure that treatment for both protozoan
and viral pathogens is appropriate.
EPA emphasizes that benchmarking is
not intended to function as a regulatory
standard. Rather, the objective of the
disinfection benchmark is to facilitate
interactions between the States and
systems for the purpose of assessing the
impact on microbial risk of proposed
significant changes to current
disinfection practices. Final decisions
regarding levels of disinfection for
Giardia lamblia and viruses beyond
those required by the SWTR that are
necessary to protect public health will
continue to be left to the States. For this
reason EPA has not mandated specific
evaluation protocols or decision
matrices for analyzing changes in
disinfection practice. EPA, however,
will provide support to the States in
making these analyses through the
issuance of guidance.
3. Request for Comments
EPA requests comment on the
proposed provisions of the inactivation
profiling and benchmarking
requirement.
E. Additional Treatment Technique
Requirements for Systems With
Uncovered Finished Water Storage
Facilities
1. What Is EPA Proposing Today?
EPA is proposing requirements for
systems with uncovered finished water
storage facilities. The proposed rule
requires that systems with uncovered
finished water storage facilities must (1)
cover the uncovered finished water
storage facility, or (2) treat storage
facility discharge to the distribution
system to achieve a 4 log virus
inactivation, unless (3) the system
implements a State-approved risk
mitigation plan that addresses physical
access and site security, surface water
runoff, animal and bird waste, and
ongoing water quality assessment, and
includes a schedule for plan
implementation. Where applicable, the
plans should account for cultural uses
by Indian Tribes.
Systems must notify the State if they
use uncovered finished water storage
facilities no later than 2 years following
LT2ESWTR promulgation. Systems
must cover or treat uncovered finished
facilities or have a State-approved risk
mitigation plan within 3 years following
LT2ESWTR promulgation, with the
possibility of a two year extension
granted by States for systems making
capital improvements. Systems seeking
approval for a risk mitigation plan must
submit the plan to the State within 2
years following LT2ESWTR
promulgation.
These provisions apply to uncovered
tanks, reservoirs, or other facilities
where water is stored after it has
undergone treatment to satisfy microbial
treatment technique requirements for
Giardia lamblia, Cryptosporidium, and
viruses. In most cases, this refers to
storage of water following all filtration
steps, where required, and primary
disinfection.
2. How Was This Proposal Developed?
Today's proposal is intended to
mitigate the water quality degradation
and increased health risks that can
result from uncovered finished water
storage facilities. In addition, these
proposed requirements for uncovered
finished water storage facilities are
consistent with recommendations of the
Stage 2 M-DBP Advisory Committee in
the Agreement in Principle (USEPA
2000a).
The use of uncovered finished water
storage facilities has been questioned
since 1930 due to their susceptibility to
contamination and subsequent threats to
public health (LeChevallier etal 1997).
Many potential sources of
contamination can lead to the
degradation of water quality in
uncovered finished water storage
facilities. These include surface water
runoff, algal growth, insects and fish,
bird and animal waste, airborne
deposition, and human activity.
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47719
Algal blooms are the most common
problem in open reservoirs and can
become a public health risk, as they
increase the presence of bacteria in the
water. Algae growth also leads to the
formation of disinfection byproducts
and causes taste and odor problems.
Some algae produce toxins that can
induce headache, fever, diarrhea,
abdominal pain, nausea, and vomiting.
Bird and animal wastes are also
common and significant sources of
contamination. These wastes may carry
microbial contaminants such as
coliform bacteria, viruses, and human
pathogens, including Vibrio cholera,
Salmonella, Mycobacteria, Typhoid,
Giardia lamblia, and Cryptosporidium
(USEPA 1999e). Microbial pathogens are
found in surface water runoff, along
with agricultural chemicals, automotive
wastes, turbidity, metals, and organic
matter (USEPA I999e, LeChevallier et
al 1997).
In an effort to minimize
contamination, systems have
implemented various controls such as
reservoir covers and liners, regular
draining and washing, security and
monitoring, bird and insect control
programs, and drainage design to
prevent surface runoff from entering the
facility (USEPA 1999e).
A number of studies have evaluated
the degradation of water quality in
uncovered finished water storage
facilities. LeChevallier et al. (1997)
compared influent and effluent samples
from six uncovered finished water
storage reservoirs in New Jersey for a
one year period. There were significant
increases in the turbidity, particle
count, total coliform, fecal coliform, and
heterotrophic plate count bacteria in the
effluent relative to the influent. Of
particular concern were fecal coliforms,
which were detected in 18 percent of
effluent samples (no influent samples
were positive for coliforms). Fecal
coliforms are used as an indicator of the
potential for contamination by
pathogens. Giardia and/or
Cryptosporidium were detected in 15%
of inlet samples and 25% of effluent
samples, demonstrating a significant
increase in the effluent. There was a
significant decrease in the chlorine
residual concentration in some effluent
samples.
Increases in algal cells, heterotrophic
plate count (HPC) bacteria, turbidity,
color, particle counts, and biomass, and
decreases in residual chlorine levels,
have been reported in other studies of
uncovered finished water reservoirs as
well (Pluntze 1974, AWWA Committee
1983, Silverman etal. 1983).
Researchers have shown that small
mammals, birds, fish, and algal growth
contribute to the microbial degradation
of an open finished water reservoir
(Graczyk et al. 1996, Geldreich 1990,
Payer and Ungar 1986, Current 1986).
As described in section II, the
IESWTR and LTlESWTR require water
systems to cover all new reservoirs,
holding tanks, or other storage facilities
for finished water. However, these rules
do not require systems to cover existing
finished water storage facilities. EPA
stated in the preamble to the final
IESWTR (63 FR 69494, December 16,
1998) (USEPA 1998a) that with respect
to requirements for existing uncovered
finished water storage facilities, the
Agency needed more time to collect and
analyze additional information to
evaluate regulatory impact. The
IESWTR preamble affirmed that EPA
would consider whether to require the
covering of existing storage facilities
during the development of subsequent
microbial regulations when additional
data to estimate national costs were
available.
Since promulgation of the IESWTR,
EPA has collected sufficient data to
estimate national cost implications of
regulatory control strategies for
uncovered finished water storage
facilities. Based on information
provided by States, EPA estimates that
there are approximately 138 uncovered
finished water storage facilities in the
United States and territories, not
including reservoirs that systems
currently plan to cover or take off-line.
Costs for covering these storage facilities
or treating the effluent, consistent with
today's proposed requirements, are
presented in section VI of this preamble
and in the Economic Analysis for the
LT2ESWTR (USEPA 2003a). Briefly,
total capital costs were estimated as
$64.4 million, resulting in annualized
present value costs of $5.4 million at a
three percent discount rate and $6.4
million at a seven percent discount rate.
Based on the findings of studies cited
in this section, EPA continues to be
concerned about contamination
occurring in uncovered finished water
storage facilities. Therefore, as
recommended by the Advisory
Committee, EPA is proposing control
measures for all systems with uncovered
finished water storage facilities. This
proposal is intended to represent a
balanced approach, recognizing both the
potentially significant but uncertain
risks associated with uncovered
finished water storage facilities and the
substantial costs of either covering them
or building alternative storage. Today's
proposal allows systems to treat the
storage facility effluent instead of
providing a cover. Alternatively, States
may determine that existing risk
mitigation is adequate, provided a
system implements a risk mitigation
plan as described in this section.
3, Request for Comments
EPA requests comment on the
proposed requirements pertaining to
uncovered finished water storage
facilities. Specifically, the Agency
would like comment on the following
issues, and requests that comments
include available supporting data or
other technical information:
• Is it appropriate to allow systems
with uncovered finished water storage
facilities to implement a risk
management plan or treat the effluent to
inactivate viruses instead of covering
the facility?
• If systems treat the effluent of an
uncovered finished water storage
facility instead of covering it, should
systems be required to inactivate
Cryptosporidium and Giardia lamblia,
since these protozoa have been found to
increase in uncovered storage facilities?
• Additional information on
contamination or health risks that may
be associated with uncovered finished
water storage facilities.
• Additional data on how
climatological conditions affect water
quality, including daily fluctuations in
the stability of the water related to
corrosion control.
* The definition of an uncovered
finished water storage facility in 40 CFR
141.2 is a tank, reservoir, or other
facility used to store water that will
undergo no further treatment except
residual disinfection and is open to the
atmosphere. There is a concern that this
definition may not include certain
systems using what would generally be
considered an uncovered finished water
storage facility. An example is a system
that applies a corrosion inhibitor
compound to the effluent of an
uncovered storage facility where water
is stored after filtration and primary
disinfection. In this case, the system
may claim that the corrosion inhibitor
constitutes additional treatment and,
consequently, the reservoir does not
meet EPA's definition of an uncovered
finished water storage facility. EPA
requests comment on whether the
definition of an uncovered finished
water storage facility should be revised
to specifically include systems that
apply a treatment such as corrosion
control to water stored in an uncovered
reservoir after the water has undergone
filtration, where required, and primary
disinfection.
F. Compliance Schedules
Today's proposal includes deadlines
for public water systems to comply with
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the proposed monitoring, reporting, and
treatment requirements. These
deadlines stem from the microbial
framework approach of the proposed
LT2ESWTR, which involves a system-
specific risk characterization through
monitoring to determine the need for
additional treatment.
1. What Is EPA Proposing Today?
a. Source water monitoring.
i. Filtered systems. Under today's
proposal, filtered systems conduct
source water Cryptosporidium
monitoring for the purpose of being
classified in one of four risk bins that
determine the extent of any additional
treatment requirements. Small filtered
systems first monitor for E. coli as a
screening analysis and are only required
to monitor for Cryptosporidium if the
mean E. coli level exceeds specified
trigger values. Note that systems that
currently provide or will provide a total
of at least 5.5 log of treatment for
Cryptosporidium are exempt from
monitoring requirements.
Large surface water systems (serving
at least 10,000-people) that filter must
sample at least monthly for
Cryptosporidium, E. coli, and turbidity
in their source water for 24 months,
beginning 6 months after promulgation
of the LT2ESWTR. Large systems must
submit a sampling schedule to their
primacy agency (in this case, EPA) no
later than 3 months after promulgation
oftheLT2ESWTR.
Small surface water systems (fewer
than 10,000 people served) that filter
must conduct biweekly E. coli sampling
in their source water for 1 year,
beginning 30 months after LT2ESWTR
promulgation. States may designate an
alternate indicator monitoring strategy
based on EPA guidance, but compliance
schedules will not change. Small
systems that exceed the indicator trigger
value (i.e., mean E. coli > 10/100 mL for
lake/reservoir sources or > 50/100 mL
for flowing stream sources) must
conduct source water Cryptosporidium
sampling twice-per-month for 1 year,
beginning 48 months after LT2ESWTR
promulgation (i.e., beginning 6 months
following the completion of E. coli
sampling). Small systems must submit
an E. coli sampling schedule to their
primacy agency no later than 27 months
after LT2ESWTR promulgation. If
Cryptosporidium monitoring is
required, small systems must submit a
Cryptosporidium sampling schedule no.
later than 45 months after LT2ESWTR
promulgation.
Large systems must carry out a second
round of source water monitoring
beginning 108 months after LT2ESWTR
promulgation, which is 6 years after
initial bin classification. Similarly,
small systems must conduct a second
round of indicator monitoring (E. coli or
other as designated by the State)
beginning 138 months after LT2ESWTR
promulgation, which is 6 years after
their initial bin classification. Small
systems that exceed the indicator trigger
value in the second round of indicator
monitoring must conduct a second
round of Cryptosporidium monitoring,
beginning 156 months after LT2ESWTR
promulgation.
Compliance dates for filtered systems
are summarized in Table IV-23.
TABLE iv-23.—SUMMARY OF COMPLIANCE DATES FOR FILTERED SYSTEMS
System type
Requirement
Compliance date
Large Systems (serve >10,000 peo-
ple).
Small Systems (serve <10,000 peo-
ple).
Submit sampling schedule '-2
Source water Cryptosporidium, E. coli and turbidity
monitoring.
Comply with additional Cryptosporidium treatment
requirements.
Second round of source water Cryptosporidium, E.
coli, and turbidity monitoring2.
Submit E. coli sampling schedule2
Source water £ coli monitoring
Second round of source water £ coli monitoring2 ...
No later than 3 months after promulgation.
Begin monthly monitoring 6 months after promulga-
tion for 24 months.
No later than 72 months after promulgation.3
Begin monthly monitoring 108 months after promul-
gation for 24 months.
No later than 27 months after promulgation.
Begin biweekly monitoring 30 months after promul-
gation for 1 year.
Begin biweekly monitoring 138 months after promul-
gation for 1 year.
Additional requirements if indicator (e.g., E. coli) trigger level is exceeded"
Submit Cryptosporidium sampling schedule '-2 ..
Source water Cryptosporidium monitoring
Comply with additional Cryptosporidium treatment
requirements.
Second round of source water Cryptosporidium
monitoring.
No later than 45 months after promulgation.
Begin twice-per-month monitoring no later than 48
months after promulgation for 1 year.
No later than 102 months after promulgation.3'5
Begin twice-per-month monitoring no later than 156
months after promulgation for 1 year.
systems may be eligible to use previously collected (grandfathered) data to meet LT2ESWTR requirements if specified quality control criteria
to mon&r if they will provide at least 5.5 log Cryptosporidium^reatment and notify EPA or the State.
-rces or exceeds 50/100 mL for systems
Bin 1 and are not required to provide Cryptospondium treatment beyond
LT1ESWTR levels.
ii. UnfiHered systems. Surface water
systems that do not filter and meet the
criteria for avoidance of filtration [40
CFR 141.71) (i.e., unfiltered systems) are
required to conduct source water
Cryptosporidium monitoring to
determine if their mean source water
Cryptosporidium level exceeds 0.01
oocysts/L. There is no E. coli screening
analysis available to small unfiltered
systems. However, both large and small
unfiltered systems conduct
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47721
Cryptosporidium monitoring on the
same schedule as filtered systems of the
same size. Note that unfiltered systems
that currently provide or will provide a
total of at least 3 log Cryptosporidium
inactivation are exempt from monitoring
requirements.
Large unfiltered systems (serving at
least 10,000 people) must conduct at
least monthly Cryptosporidium
sampling for 24 months, beginning 6
months after LT2ESWTR promulgation.
Small unfiltered systems (serving fewer
than 10,000 people) must conduct at
Jeast twice-per-month Cryptosporidium
sampling for 12 months, beginning 48
months after LT2ESWTR promulgation.
Large systems must submit a
Cryptosporidium sampling schedule to
EPA no later than 3 months after
LT2ESWTR promulgation, and small
systems must submit a sampling
schedule to their State no later than 45
months after LT2ESWTR promulgation.
Unfiltered systems are required to
conduct a second round of
Cryptosporidium monitoring on the
same schedule as filtered systems of the
same size. Large systems must carry out
a second round of Cryptosporidium
monitoring, beginning 108 months after
LT2ESWTR promulgation. Small
systems must perform a second round of
Cryptosporidium monitoring, beginning
156 months after LT2ESWTR
promulgation.
Compliance dates for unfiltered
systems are summarized in Table IV-24.
TABLE IV-24.—SUMMARY OF COMPLIANCE DATES FOR UNFILTERED SYSTEMS
System type
Requirement
Compliance date
Large Systems (serve >10,000 peo-
ple).
Submit sampling schedule1 ...
Source water Cryptosporidium monitoring
Small Systems (serve < 10,000
people).
Comply with Cryptosporidium inactivation require-
ments.
Second round of source water Cryptosporidium
monitoring.
Submit sampling schedule1
Source water Cryptosporidium monitoring
Comply with Cryptosporidium inactivation require-
ments.
Second round of source water Cryptosporidium
monitoring.
No later than 3 months after promulgation.
Begin monthly monitoring [6 months after promulga-
tion for 24 months.
No later than 72 months after promulgation.2
Begin monthly monitoring 108 months after promul-
gation for 24 months.
No later than 45 months after promulgation.
Begin twice-per-month monitoring no later than 48
months after promulgation for 1 year.
No later than 102 months after promulgation.2
Begin twice-per-month monitoring no later than 156
months after promulgation for 1 year.
1 Systems may be eligible to use previously collected (grandfathered) data to meet LT2ESWTR requirements if specified quality control criteria
are met (described in section IV.A.I.d).
2 States may grant up to an additional two years for systems making capital improvements.
b. Treatment requirements. Filtered
systems must determine their bin
classification and unfiltered systems
must determine their mean source water
Cryptosporidium level within 6 months
of the scheduled month for collection of
their final Cryptosporidium sample in
the first round of monitoring. This 6
month period provides time for systems
to receive all sample analysis results
from the laboratory, analyze the data,
and work with their primacy agency.
Filtered systems have 3 years
following initial bin classification to
meet any additional Cryptosporidium
treatment requirements. This equates to
compliance dates of 72 months after
LT2ESWTR promulgation for large
systems and 102 months after
LT2ESWTR promulgation for small
systems (see Table IV-23). Unfiltered
systems must comply with
Cryptosporidium treatment
requirements on the same schedule as
filtered systems of the same size (see
Table IV-24). The State may grant
systems an additional two years to
comply when capital investments are
necessary, as specified in the Safe
Drinking Water Act (section
Systems with uncovered finished
water storage facilities are required to
comply with the provisions described in
section IV.E by 36 months following
LT2ESWTR promulgation, with the
possibility of a 2 year extension granted
by the State for systems making capital
improvements. Systems seeking
approval for a risk mitigation plan must
submit the plan to the State within 24
months following LT2ESWTR
promulgation.
Systems must comply with additional
Cryptosporidium treatment
requirements by implementing one or
more treatment processes or control
strategies from the microbial toolbox.
Most of the toolbox components require
submission of documentation to the
State demonstrating compliance with
design and/or implementation criteria
required to receive credit. Compliance
dates for reporting requirements
associated with microbial toolbox
components are presented in detail in
section IV.], Reporting and
Recordkeeping Requirements.
c. Disinfection benchmarks for
Giardia lamblia and viruses. Today's
proposed LT2ESWTR includes
disinfection profiling and benchmarking
requirements, which consist of three
major components: applicability
determination, characterization of
disinfection practice, and State review
of proposed changes in disinfection
practice. Each of these components is
discussed in detail in section W.D.
Compliance deadlines associated with
each of these components, including
associated reporting requirements, are
stated in section IV J, Reporting and
Recordkeeping Requirements.
2. How Was This Proposal Developed?
The compliance dates in today's
proposal reflects the risk-targeted
approach of the proposed LT2ESWTR,
wherein additional treatment
requirements are based on a system
specific risk characterization as
determined through source water
monitoring. Additionally, they are
designed to allow for systems to
simultaneously comply with the
LT2ESWTR and Stage 2 DBPR in order
to balance risks in the control of
microbial pathogens and DBPs. These
dates are consistent with
recommendations from the Stage 2 M-
DBP Federal Advisory Committee.
Under the LT2ESWTR, large systems
will sample for Cryptosporidium for a
period of two years in order to
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characterize source water pathogen
levels and capture a degree of annual
variability. To expedite the date by
which systems will provide additional
treatment where high risk source waters
are identified, large system
Cryptosporidium monitoring will begin
six months after promulgation of the
LT2ESWTR. Upon completion of
Cryptosporidium monitoring, systems
will have six months to work with their
primacy agency to determine their bin
classification. Beginning at this point,
which is three years following
LT2ESWTR promulgation, large systems
will have three years to implement the
treatment processes or control strategies
necessary'to comply with any additional
treatment requirements stemming from
bin classification.
Other large system compliance dates
in areas like approval of grandfathered
monitoring data, disinfection profiling
and benchmarking, and reporting
deadlines associated with microbial
toolbox components all stem from the
Cryptosporidium monitoring and
treatment compliance schedule.
With respect to small systems under
the LT2ESWTR, EPA is proposing that
small systems first monitor for E. coli as
a screening analysis in order to reduce
the number of small systems that incur
the cost of Cryptosporidium monitoring.
However, due to limitations in available
data, the Agency has determined that it
is necessary to use data generated by
large systems under the LT2ESWTR to
confirm or refine the E. coli indicator
criteria that will trigger small system
Cryptosporidium monitoring.
Consequently, small system indicator
monitoring will begin at the conclusion
of large system monitoring. This
approach was recommended by the
Advisory Committee.
Accordingly, small systems will
monitor for E. coli for one year,
beginning 30 months after LT2ESWTR
promulgation. Following this, small
systems will have six months to
determine if they are required to
monitor for Cryptosporidium and, if so,
contract with an approved analytical
laboratory. Cryptosporidium monitoring
by small systems will be conducted for
one year, which, when added to the one
year of E. coli monitoring, equals two
years of source water monitoring. This
is equivalent to the time period large
systems spend in source water
monitoring.
The time periods associated with bin
assignment and compliance with
additional treatment requirements for
small systems are the same as those
proposed for large systems. Specifically,
small systems will have six months to
work with their States to determine
their bin classification following the
conclusion of Cryptosporidium
sampling. From this point, which is 5.5
years after LT2ESWTR promulgation,
small systems have three years to meet
any additional treatment requirements
resulting from bin classification. States
can grant additional time to small
systems for compliance with treatment
technique requirements through
granting exemptions (see SDWA section
1416).
3. Request for Comments
EPA requests comments on the
treatment technique compliance
schedules for large and small systems in
today's proposal, including the
following issues:
Time Window Between Large and Small
System Monitoring
Under the current proposal, small
filtered system E. coli monitoring begins
in the month following the end of large
system Cryptosporidium, E. coli, and
turbidity monitoring. EPA plans to
evaluate large system monitoring results
on an ongoing basis as the data are
reported to determine if any refinements
to the E. coli levels that trigger small
system Cryptosporidium monitoring are
necessary. If such refinements were
deemed appropriate, EPA would issue
guidance to States, which can establish
alternative trigger values for small
system monitoring under the
LT2ESWTR.
This implementation schedule does
not leave any time between the end of
large system monitoring and the
initiation of small system monitoring.
Consequently, if it is necessary to
provide guidance on alternative trigger
values prior to when small system
monitoring begins, such guidance
would be based on less than the full set
of large system results (e.g., first 18
months of large system data). EPA
requests comment on whether an
additional time window between the
end of large system monitoring and the
beginning of small system monitoring is
appropriate and, if so, how long such a
window should be.
Implementation Schedule for
Consecutive Systems
The Stage 2 M-DBP Agreement in
Principle (65 FR 83015, December 29,
2000) (USEPA 2000a) continues the
principle of simultaneous compliance to
address microbial pathogens and
disinfection byproducts. Systems are
generally expected to address
LT2ESTWR requirements concurrently
with those of the Stage 2 DBPR (as noted
earlier, the Stage 2 DBPR is scheduled
to be proposed later this year and to be
promulgated at the same time as the
LT2ESWTR).
As with the LT2ESWTR, small water
systems (< 10,000 served) generally
begin monitoring and must be in
compliance with the Stage 2 DBPR at a
date later than that for large systems.
However, the Advisory Committee
recommended that small systems that
buy/receive from or sell/deliver finished
water to a large system (that is, they are
part of the same "combined distribution
system") comply with Stage 2 DBPR
requirements on the same schedule as
the largest system in the combined
distribution system. This approach is
intended to ensure that systems
consider impacts throughout the
combined distribution system when
making compliance decisions (e.g.
selecting new technologies or making
operational modifications) and to
facilitate all systems meeting the
compliance deadlines for the rule.
The issue of combined distribution
systems associated with systems buying
and selling water is expected to be of
less significance for the LT2ESWTR.
The requirements of the LT2ESWTR
apply to systems treating raw surface
water and generally will not involve
compliance steps when systems
purchase treated water. Consequently,
the compliance schedule for today's
proposal does not address combined
distribution systems. However, this
proposed approach raises the possibility
that a small system treating surface
water and selling it to a large system
could be required to take compliance
steps at an earlier date under the Stage
2 DBPR than under the LT2ESWTR.
While a small system in this situation
could choose to comply with the
LT2ESWTR on an earlier schedule, the
two rules would not require
simultaneous compliance. EPA requests
comment on how this scenario should
be addressed in the LT2ESWTR.
G. Public Notice Requirements
1. What Is EPA Proposing Today?
EPA is proposing that under the
LT2ESWTR, a Tier 2 public notice will
be required for violations of additional
treatment requirements and a Tier 3
public notice will be required for
violations of monitoring and testing
requirements. Where systems violate
LT2ESWTR treatment requirements,
today's proposal requires the use of the
existing health effects language for
microbiological contaminant treatment
technique violations, as stated in 40
CFR 141 Subpart Q, Appendix B.
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47723
2. How Was This Proposal Developed?
In 2000, EPA published the Public
Notification Rule (65 FR 25982, May 4,
2000) (USEPA 2000d), which revised
the general public notification
regulations for public water systems in
order to implement the public
notification requirements of the 1996
SDWA amendments. This regulation
established the requirements that public
water systems must follow regarding the
form, manner, frequency, and content of
a public notice. Public notification of
violations is an integral part of the
public health protection and consumer
right-to-know provisions of the 1996
SDWA Amendments.
Owners and operators of public water
systems are required to notify persons
served when they fail to comply with
the requirements of a NPDWR, have a
variance or exemption from the drinking
water regulations, or are facing other
situations posing a risk to public health.
The public notification requirements
divide violations into three categories
(Tier 1, Tier 2 and Tier 3) based on the
seriousness of the violations, with each
tier having different public notification
requirements,
EPA has limited its list of violations
and situations routinely requiring a Tier
1 notice to those with a significant
potential for serious adverse health
effects from short term exposure. Tier l
violations contain language specified by
EPA that concisely and in non-technical
terms conveys to the public the adverse
health effects that may occur as a result
of the violation. States and water
utilities may add additional information
to each notice, as deemed appropriate
for specific situations. A State may
elevate to Tier 1 other violations and
situations with significant potential to
have serious adverse health effects from
short-term exposure, as determined by
the State.
Tier 2 public notices address other
violations with potential to have serious
adverse health effects on human health.
Tier 2 notices are required for the
following situations:
• All violations of the MCL,
maximum residual disinfectant level
(MRDL) and treatment technique
requirements, except where a Tier 1
notice is required or where the State
determines that a Tier 1 notice is
required; and
* Failure to comply with the terms
and conditions of any existing variance
or exemption.
Tier 3 public notices include all other
violations and situations requiring
public notice, including the following
situations:
• A monitoring or testing procedure
violation, except where a Tier 1 or 2
notice is already required or where the
State has elevated the notice to Tier 1
or 2; and
• Operation under a variance or
exemption.
The State, at its discretion, may
elevate the notice requirement for
specific monitoring or testing
procedures from a Tier 3 to a Tier 2
notice, taking into account the potential
health impacts and persistence of the
violation.
As part of the IESWTR, EPA
established health effects language for
violations of treatment technique
requirements for microbiological
contaminants. EPA believes this
language, which was developed with
consideration of Cryptosporidium
health effects, is appropriate for
violations of additional
Cryptosporidium treatment
requirements under the LT2ESWTR.
3. Request for Comment
EPA requests comment on whether
the violations of additional treatment
requirements for Cryptosporidium
under the LT2ESWTR should require a
Tier 2 public notice and whether the
proposed health effects language is
appropriate.
H. Variances and Exemptions
SDWA section 1415 allows States to
grant variances from national primary
drinking water regulations under certain
conditions; section 1416 establishes the
conditions under which States may
grant exemptions to MCL or treatment
technique requirements. For the reasons
presented in the following discussion,
EPA has determined that systems will
not be eligible for variances or
exemptions to the requirements of the
LT2ESWTR.
1 . Variances
Section 1415 specifies two provisions
under which general variances to
treatment technique requirements may
be granted:
(1) A State that has primacy may grant
a variance to a system from any
requirement to use a specified treatment
technique for a contaminant if the
system demonstrates to the satisfaction
of the State that the treatment technique
is not necessary to protect public health
because of the nature of the system's
raw water source. EPA may prescribe
monitoring and other requirements as
conditions of the variance (section
(2) EPA may grant a variance from any
treatment technique requirement upon a
showing by any person that an
alternative treatment technique not
included in such requirement is at least
as efficient in lowering the level of the
contaminant (section 1415(a)(3)).
EPA does not believe the first
provision for granting a variance is
applicable to the LT2ESWTR because
Cryptosporidium treatment technique
requirements under this rule account for
the degree of source water
contamination. Systems initially comply
with the LT2ESWTR by conducting
source water monitoring for
Cryptosporidium. Filtered systems are
required to provide additional treatment
for Cryptosporidium only if the source
water concentration exceeds a level
where current treatment does not
provide sufficient protection. All
unfiltered systems are required to
provide a baseline of 2 log inactivation
of Cryptosporidium to achieve finished
water risk levels comparable to filtered
systems; however, unfiltered systems
are required to achieve 3 log
inactivation only if the source water
level exceeds 0.01 oocysts/L.
The second provision for granting a
variance is not applicable to the
LT2ESWTR because the treatment
technique requirements of this rule
specify the degree to which systems
must lower their source water
Cryptosporidium level (e.g., 4, 5, and 5.5
log reduction in Bins 2, 3, and 4,
respectively). The LT2ESWTR provides
broad flexibility in how systems achieve
the required level of Cryptosporidium
reduction, as shown in the discussion of
the microbial toolbox in section VI.C
Moreover, the microbial toolbox
contains an option for Demonstration of
Performance, under which States can
award treatment credit based on the
demonstrated efficiency of a treatment
process in reducing Cryptosporidium
levels. Thus, there is no need for this
type of variance under the LT2ESWTR.
SDWA section 1415(e) describes small
system variances, but these cannot be
granted for a treatment technique for a
microbial contaminant. Hence, small
system variances are not allowed for the
LT2ESWTR.
2. Exemptions
Under SDWA section 1416(a), a State
may exempt any public water system
from a treatment technique requirement
upon a finding that (1) due to
compelling factors (which may include
economic factors such as qualification
of the system as serving a disadvantaged
community), the system is unable to
comply with the requirement or
implement measures to develop an
alternative source of water supply; (2)
the system was in operation on the
effective date of the treatment technique
requirement, or for a system that was
not in operation by that date, no
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Federal Register/Vol. 68, No. 154/Monday. August 11. 2003/Proposed Rules
reasonable alternative source of
drinking water is available to the new
system; (3) the exemption will not result
in an unreasonable risk to health; and
(4) management or restructuring
changes (or both) cannot reasonably
result in compliance with the Act or
improve the quality of drinking water.
IT EPA or the State grants an
exemption to a public water system, it
must at the same time prescribe a
schedule for compliance (including
increments of progress or measures to
develop an alternative source of water
supply) and implementation of
appropriate control measures that the
State requires the system to meet while
the exemption is in effect. Under section
1416(b)(2}(A), the schedule shall require
compliance as expeditiously as
practicable (to be determined by the
State), but no later than three years after
the otherwise applicable compliance
date for the regulations established
pursuant to section 1412(b)(10), For
public water systems that do not serve
more than a population of 3,300 and
that need financial assistance for the
necessary improvements, EPA or the
State may renew an exemption for one
or more additional two-year periods, but
not to exceed a total of six years.
A public water system shall not be
granted an exemption unless it can
establish that: (1) The system cannot
meet the standard without capital
improvements that cannot be completed
prior to the date established pursuant to
section 1412(b)(10); or (2) in the case of
a system that needs financial assistance
for the necessary implementation, the
system has entered into an agreement to
obtain financial assistance pursuant to
section 1452 or any other Federal or
state program; or (3) the system has
entered into an enforceable agreement to
become part of a regional public water
system.
EPA believes that granting an
exemption to the Ctyptosporidium
treatment requirements of the
LT2ESWTR would result in an
unreasonable risk to health. As
described in section 1I.C,
Cryptosporidium causes acute health
effects, which may be severe in sensitive
subpopulations and include risk of
mortality. Moreover, the additional
Cryptosporidium treatment
requirements of the LT2ESWTR are
targeted to systems with the highest
degree of risk. Due to these factors, EPA
is not proposing to allow exemptions
under the LT2ESWTR.
3. Request for Comment
a. Variances. EPA requests comment
on the determination that the provisions
for granting variances are not applicable
to the proposed LT2ESWTR, specifically
including Cryptosporidium inactivation
requirements for unfiltered systems.
In theory it would be possible for an
unfiltered system to demonstrate raw
water Cryptosporidium levels that were
3 log lower than the cutoff for bin \ for
filtered systems and, thus, that it may be
providing comparable public health
protection without additional
inactivation. However, EPA has
determined that in practice it is not
currently economically or
technologically feasible for systems to
ascertain the level of Cryptosporidium
at this concentration. This is due to the
extremely large number and volume of
samples that would be necessary to
make this demonstration with sufficient
confidence. Based on this determination
and the Cryptosporidium occurrence
data described in section III.C, EPA is
not proposing to allow unfiltered
systems to demonstrate raw water
Cryptosporidium levels low enough to
avoid inactivation requirements. EPA
.requests comment on this approach.
b. Exemptions. EPA requests
comment on the determination that
granting an exemption to the
Cryptosporidium treatment
requirements of the LT2ESWTR would
result in an unreasonable risk to health.
/, Requirements for Systems To Use
Qualified Operators
The SWTR established a requirement
that each public water system using a
surface water source or a ground water
source under the direct influence of
surface water must be operated by
qualified personnel who meet the
requirements specified by the State (40
CFR 141.70). The Stage 1 DBPR
extended this requirement to include all
systems affected by that rule, and
required that States maintain a register
of qualified operators (40 CFR
141.130(c)). While the proposed
LT2ESWTR establishes no new
requirements regarding the operation of
systems by qualified personnel, the
Agency would like to emphasize the
important role that qualified operators
play in delivering safe drinking water to
the public. EPA encourages States that
do not already have operator
certification programs in effect to
develop such programs. States should
also review and modify, as required,
their qualification standards to take into
account new technologies (e.g.,
ultraviolet disinfection) and new
compliance requirements.
/. System Reporting and Recordkeeping
Requirements
1. Overview
Today's proposal includes reporting
and recordkeeping requirements
associated with proposed monitoring
and treatment requirements. As
described earlier, systems must conduct
source water monitoring to determine a
treatment bin classification for filtered
systems or a mean Cryptosporidium
level for unfiltered systems. Systems
with previously collected monitoring
data may be able to use (i.e.,
grandfather) those data in lieu of
conducting new monitoring. Following
source water monitoring, systems will
be required to comply with any
additional Cryptosporidium treatment
requirements by implementing
treatment and control strategies from a
microbial toolbox of options. Systems
must conduct a second round of source
water monitoring six years after bin
classification.
In addition, systems using uncovered
finished water storage facilities must
cover the facility or provide treatment
unless the system implements a State-
approved risk management strategy.
Certain systems will be required to
conduct disinfection profiling and
benchmarking.
The proposed rule requires public
water systems to submit schedules for
Cryptosporidium, E. coli, and turbidity
sampling at least 3 months before
monitoring must begin. Source water
sample analysis results must be reported
not later than ten days after the end of
first month following the month when
the sample is collected. As described
later, large systems (at least 10,000
people served) will report monitoring
results from the initial round of
monitoring directly to EPA through an
electronic data system. Small systems
will report monitoring results to the
State. Both small and large systems will
report monitoring results from the
second round of monitoring to the State.
Systems must report a bin
classification (filtered systems) or mean
Cryptosporidium level (unfiltered
systems) within six months following
the month when the last sample in a
particular round of monitoring is
^scheduled to be collected. If systems are
Required to provide additional treatment
for Cryptosporidium, they must report
regarding the use of microbial toolbox
components. Systems must notify the
State within 24 months following
promulgation of the rule if they use
uncovered finished water storage
facilities. Systems must also make
reports related to disinfection profiling
and benchmarking. Reporting
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47725
activities are summarized in Tables IV-
25 to IV-28.
requirements associated with these
TABLE IV-25.— SUMMARY OF INITIAL LARGE FILTERED SYSTEM REPORTING REQUIREMENTS
You must report the following items
On the following schedule
Sampling schedule for Cryptosporidium, E. coli, and turbidity No later than 3 months after promulgation.
monitoring.
Results of Cryptosporidium, E. coli, and turbidity analyses No later than 10 days after the end of the first month following the month in
which the sample is collected.
Bin determination No later than 36 months after promulgation.
Demonstration of compliance with additional treatment require- Beginning 72 months after promulgation1 (See table IV-34).
ments.
Disinfection profiling component reports See Table IV-35.
1 States may grant an additional two years for systems making capital improvements.
TABLE IV-26.—SUMMARY OF INITIAL SMALL FILTERED SYSTEM REPORTING REQUIREMENTS
You must report the following items On the following schedule
Sampling schedule for E. coli monitoring No later than 27 months after promulgation.
Results of E. coli analyses (unless State approves a different No later than 10 days after the end of the first month following the month in
indicator). which the sample was collected.
Mean E coli concentration (unless State approves a different No later than 45 months after promulgation.
indicator).
Disinfection profiling component reports See Table IV-36.
Additional requirements if E. coli trigger level is exceeded1
Sampling schedule for Cryptosporidium monitoring No later than 45 months after promulgation.
Results of Cryptosporidium analyses No later than 10 days after the end of the first month following the month in
which the sample is collected.
Bin determination No later than 66 months after promulgation.
Demonstration of compliance with additional treatment require- Beginning 102 months after promulgation2 (See Table IV-34).
ments.
11f the E. coli annual mean concentration exceeds 10/100 mL for systems using lakes/reservoirs or exceeds 50/100 mL for systems using flow-
ing streams, then systems must conduct Cryptosporidium monitoring. States may approve alternative indicator criteria to trigger Cryptosporidium
monitoring.
2 States may grant an additional two years for systems making capital improvements.
TABLE IV-27 — SUMMARY OF INITIAL LARGE UNFILTERED SYSTEM REPORTING REQUIREMENTS
You must report the following items On the following schedule
Cryptosporidium sampling schedule No later than 3 months after promulgation.
Results of Cryptosporidium analyses No later than 10 days after the end of the first month following the month in
which the sample was collected.
Determination of mean Cryptosporidium concentration No later than 36 months after promulgation.
Disinfection profiling component reports See Table IV-35.
Demonstration of compliance with Cryptosporidium inactivation Beginning 72 months after promulgation1 (see Table IV-34).
requirements.
1 States may grant an additional two years for systems making capital improvements.
TABLE IV-28.-—SUMMARY OF INITIAL SMALL UNFILTERED SYSTEM REPORTING REQUIREMENTS
You must report the following items On the following schedule
Cryptosporidium sampling schedule No later than 45 months after promulgation.
Results of Cryptosporidium analyses No later than 10 days after the end of the first month following the month in
which the sample was collected.
Determination of mean Cryptosporidium concentration No later than 66 months after promulgation.
Disinfection profiling component reports See Table IV-35.
Demonstration of compliance with Cryptosporidium inactivation Beginning 102 months after promulgation1 (see Table IV-34).
requirements.
1 States may grant an additional two years for systems making capital improvements.
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Federal Register/Vol. 68, No. 154/Monday. August 11. 2003 / Proposed Rules
2. Reporting Requirements for Source
Water Monitoring
a. Data elements to be reported.
Proposed reporting requirements for
LT2ESWTR monitoring stem from
proposed analytical method
requirements. As stated in sections IV.K
and 1V.L, systems must have
Cryptosporidium analyses conducted by
EPA-approved laboratories using
Methods 1622 or 1623. E. coli analyses
must be performed by State-approved
laboratories using the E. coli methods
proposed for approval in section IV.K.
Systems are required to report the data
elements specified in Table IV-29 for
each Cryptosporidium analysis. To
comply with LT2ESWTR requirements,
only the sample volume filtered and the
number of oocysts counted must be
reported for samples in which at least
10 L is filtered and all of the sample
volume is analyzed. Additional
information is required for samples
where the laboratory analyzes less than
10 L or less than the full sample volume
collected. Table IV-30 presents the data
elements that systems must report for E.
coli analyses.
As described in the following section,
EPA is developing a data system to
manage and analyze the microbial
monitoring data that will be reported by
large systems under the LT2ESWTR.
EPA is exploring approaches for
application of this data system to
support small system data reporting as
well. Systems, or laboratories acting as
the systems' agents, must keep Method
1622/1623 bench sheets and slide
examination report forms until 36
months after an equivalent round of
source water monitoring has been
completed (e.g., second round of
Cryptosporidium monitoring).
TABLE IV-29.—PROPOSED Cryptosporidium DATA ELEMENTS TO BE REPORTED
Data element
Reason for data element
Identifying information
PWSID
Facility ID
Sample collection point
Sample collection date
Sample type (field or matrix spike)1
Needed to associate plant with public water system.
Needed to associate sample result with facility.
Needed to associate sample result with sampling point.
Needed to determine that utilities are collecting samples at the frequency required.
Needed to distinguish field samples from matrix samples for recovery calculations.
Sample results
Sample volume filtered (L), to nearest 1/4 L2
Was 100% of filtered volume examined?3 ...
• Number of oocysts counted
Needed to verify compliance with sample volume requirements.
Needed to calculate the final concentration of oocysts/L and determine if volume ana-
lyzed requirements are met.
Needed to calculate the final concentration of oocysts/L.
For matrix spike samples, sample volume spiked and estimated number of oocysts spiked must be reported. These data are not required for
^
processed
TABLE IV-30.— PROPOSED E. coli DATA ELEMENTS TO BE REPORTED
Data element
Reason for collecting data element
Identifying Information __
PWS ID
Needed to associate analytical result with public water system.
Needed to associate plant with public water system.
Needed to associate sample result with sampling point.
Needed to determine that utilities are collecting samples at the frequency required.
Needed to associate analytical result with analytical method.
Needed to verify that an approved method was used and call up correct web entry form.
Needed to assess Cryptosporidium indicator relationships.
Sample result {although not required, the laboratory also will have the option of entering primary measure-
ments for a sample into the LT2ESWTR internet-based database to have the database automatically cal-
culate the sample result).
Turbldltv Information .
Turbidity result
Needed to assess Cryptosporidium indicator relationships.
b. Data system. Because source water
monitoring by large systems (serving at
least 10,000 people) will begin 6 months
following promulgation of the
LT2ESWTR, EPA expects to act as the
primacy agency with oversight
responsibility for large system sampling,
analysis, and data reporting. To
facilitate collection and analysis of large
system monitoring data, EPA is
developing an Internet-based electronic
data collection and management system.
This approach is similar to that used
under the Unregulated Contaminants
Monitoring Rule (UCMR) (64 FR 50556,
September 17,1999) (USEPA 1999c).
Analytical results for
Cryptosporidium, E. coli, and turbidity
analyses will be reported directly to this
database using web forms and software
that can be downloaded free of charge.
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47727
The data system will perform logic
checks on data entered and calculate
final results from primary data (where
necessary). This is intended to reduce
reporting errors and limit the time
involved in investigating, checking, and
correcting errors at all levels. EPA will
make large system monitoring data
available to States when States assume
primacy for the LT2ESWTR or earlier
under State agreements with EPA.
Large systems should instruct their
laboratories to electronically enter
monitoring results into the EPA data
system using web-based manual entry
forms or by uploading XML files from
laboratory information management
systems (LIMS). After data are
submitted by a laboratory, systems may
review the results on-line. If a system
believes that a result was entered into
the data system erroneously, the system
may notify the laboratory to rectify the
entry. In addition, if a system believes
that a result is incorrect, the system may
submit the result as a contested result
and petition EPA or the State to
invalidate the sample. If a system
contests a sample result, the system
must submit a rationale to the primacy
agency, including a supporting
statement from the laboratory, providing
a justification. Systems may arrange
with laboratories to review their sample
results prior to the results being entered
into the EPA data system. Also, if a
system determines that its laboratory
does not have the capability to report
data electronically, the system can
submit a request to EPA to use an
alternate reporting format.
Regardless of the reporting process
used, systems are required to report an
analytical monitoring result to the
primacy agency no later than 10 days
after the end of the first month
following the month when the sample
was collected. As described in section
IV.A.l, if a system is unable to report a
valid Cryptosporidium analytical result
for a scheduled sampling date due to
failure to comply with the analytical
method requirements (e.g., violation of
quality control requirements), the
system must collect a replacement
sample within 14 days of being notified
by the laboratory or the State that a
result cannot be reported for that date
and must submit an explanation for the
replacement sample with the analytical
results. A system will not incur a
monitoring violation if the State
determines that the failure to report a
valid analysis result was due to
circumstances beyond the control of the
system. However, in all cases the system
must collect a replacement sample.
The data elements to be collected by
the electronic data system will enhance
the reliability of the microbial data
generated under the LT2ESWTR, while
reducing the burden on the analytical
laboratories and public water systems.
Tables IV-31 and IV-32 summarize the
system's data analysis functions for
Cryptosporidium measurements.
TABLE IV-31— LT2ESWTR DATA SYSTEM FUNCTIONS FOR Cryptosporidium DATA
Value calculated
Formula
Applicability to sample
types
Field
Matrix
spike
Calculation of sample volume ana-
lyzed.
Pellet volume analyzed
Calculation of oocysts/L
Calculation of estimated number of
oocysts spiked/L.
Calculation of percent recoveries for
MS samples.
(Volume filtered) * (resuspended concentrate volume transferred to IMS/re-
suspended concentrate volume).
(pellet volume)*(resuspended concentrated volume transferred to IMS/resus-
pended concentrate volume).
(Number of oocysts counted)/(sample volume analyzed) ,
(Number of oocysts spiked)/(sample volume spiked)
Yes
Yes
Yes
No .
((Calculated # of oocysts/L for the MS sample)—(Calculated # of oocysts/L
in the associated field sample)) / (Estimated number of oocysts spiked/L)*
100%.
No
Yes.
Yes.
Yes.
Yes.
Yes.
TABLE IV-32 — LT2ESWTR DATA SYSTEM FUNCTIONS FOR Cryptosporidium COMPLIANCE CHECKS
LT2 requirements
Description
Sample volume analysis
Schedule met
Specifies that the LT2 requirements for sample volume analyzed were met when:
• volume analyzed is > 10 L.
» volume analyzed is < 10 L and pellet volume analyzed is at least 2 ml.
• volume analyzed < 10 L and pellet volume analyzed < 2 mL and 100% of filtered volume examined= Y and two
filters were used.
Specifies that the LT2 requirements for sample volume analyzed were not met when;
• volume analyzed < 10 L and pellet volume analyzed is < 2 ml and 100% of filtered volume examined= N.
• volume analyzed is < 10 L and pellet volume analyzed < 2 mL and only 1 filter used.
Specifies that the predetermined sampling schedule is met when the sample collection data is within ± 2 days of
the scheduled date.
c. Previously collected monitoring
data. Table IV-33 provides a summary
of the items that systems must report to
EPA for consideration of previously
collected (grandfathered) monitoring
data under the LT2ESWTR. For each
field and matrix spike (MS) sample,
systems must report the data elements
specified in Table IV-29. In addition,
the laboratory that analyzed the samples
must submit a letter certifying that all
Method 1622 and 1623 quality control
requirements (including ongoing
precision and recovery (OPR) and
method blank (MB) results, holding
times, and positive and negative
staining controls) were performed at the
required frequency and were acceptable.
Alternatively, the laboratory may
provide for each field, MS, OPR, and
MB sample a bench sheet and sample
examination report form (Method 1622
and 1623 bench sheets are shown in
USEPA 2003h).
Systems must report all routine
source water Cryptosporidium
monitoring results collected during the
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period covered by the previously
collected data that have been submitted.
This applies to all samples that were
collected from the sampling location
used for monitoring, not spiked, and
analyzed using the laboratory's routine
process for Method 1622 or 1623
analyses, including analytical technique
and QA/QC. Other requirements
associated with use of previously
collected data are specified in section
IV.A.l.d. Where applicable, systems
must provide documentation addressing
the dates and reason(s) for re-sampling,
as well as the use of presedimentation,
off-stream storage, or bank filtration
during monitoring. Review of the
submitted information, along with the
results of the quality assurance audits of
the laboratory that produced the data,
will be used to determine whether the
data meet the requirements for
grandfathering.
TABLE iv-33.—ITEMS THAT MUST BE REPORTED FOR CONSIDERATION OF GRANDFATHERED MONITORING DATA
The following items must be reported
On the following schedule
Data elements listed in Table IV-29 for each field and MS sample
Letter from laboratory certifying that method-specified QC was performed at re-
quired frequency and was acceptable.
OR
Method 1622/1623 bench sheet and sample examination report form for each field,
MS, OPR, and method blank sample.
Letter from system certifying (1) that all source water data collected during the time
period covered by the previously collected data have been submitted and (2) that
the data represent the plant's current source water.
Where applicable, documentation addressing the dates and reason(s) for re-sam-
pling, as well as the use of presedimentation, off-stream storage, or bank filtration
during monitoring.
No later than 2 months after promulgation if the system
does not intend to conduct new monitoring under the
LT2ESWTR.
OR
No later than 8 months after promulgation if the system in-
tends to conduct new monitoring under the LT2ESWTR.
1 See section IV.A.1. for details.
3. Compliance With Additional
Treatment Requirements
Under the proposed LT2ESWTR,
systems may choose from a "toolbox" of
management and treatment options to
meet their additional Cryptosporidium
treatment requirements. In order to
receive credit for toolbox components,
systems must initially demonstrate that
they comply with any required design
and implementation criteria, including
performance validation testing.
Additionally, systems must provide
monthly verification of compliance with
any required operational criteria, as
shown through ongoing monitoring.
Required design, implementation,
operational, and monitoring criteria for
toolbox components are described in
section IV.C. Proposed reporting
requirements associated with these
criteria are shown in Table IV-34 for
both large and small systems.
TABLE IV-34.—TOOLBOX REPORTING REQUIREMENTS
Toolbox option
(potential
Cryptosporidium re-
duction log credit)
Watershed Control
Program (WCP)
(0 5 loa)
\V'X* tuyf
Pre-sedimentation ,
{0.5 log) {new ba-
sins)
Two-Stage Lime Soft-
ening (0.5 log)
You must submit the following items
Notify State of intention to develop WCP
9nhmit initial WCP olan to State
Annual program status report and State-approved watershed
survey report.
Request for re-approval and report on the previous approval
period.
Monthly verification of:
Continuous basin operation
Treatment of 100% of the flow
Continuous addition of a coagulant
At least 0.5 log removal of influent turbidity based on the
monthly mean of daily turbidity readings for 11 of the 12
previous months
Monthly verification of:
Continuous operation of a second clarification step between
the primary clarifier and fitter
Presence of coagulant (may be lime) in first and second stage
clarifiers
Both clarifiers treat 100% of the plant flow
On the following sched-
ule1
(systems serving £10,000
people)
No later than 48 months
after promulgation
No later than 60 months
after promulgation
By a date determined by
the State, every 12
months, beginning 84
months after promulga-
tion
No later than 6 months
prior to the end of the
current approval period
or by a date previously
determined by the State
Monthly reporting within
10 days following the
month in which the
monitoring was con-
ducted, beginning 72
months after promulga-
tion
No later than 72 months
after promulgation
On the following sched-
ule i
(systems serving < 10,000
people)
No later than 78 months
after promulgation.
No later than 90 months
after promulgation.
By a date determined by
the State, every 12
months, beginning 114
months after promulga-
tion.
No later than 6 months
prior to the end of the
current approval period
or by a date previously
determined by the State.
Monthly reporting within
10 days following the
month in which the
monitoring was con-
ducted, beginning 102
months after promulga-
tion.
No later than 102 months
after promulgation.
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47729
TABLE IV-34.—TOOLBOX REPORTING REQUIREMENTS—Continued
toolbox option
(potential
Cryptosporidium re-
duction log credit)
Bank filtration (0.5 or
1.0 log) (new)
Combined filter per-
formance (0.5 log)
Membranes (MF, UF,
NF, RO) (2.5 log or
greater based on
verification/integrity
testing)
Bag filters (1.0 log)
and Cartridge filters
(2.0 log)
Chlorine dioxide (log
credit based on
CT)
Ozone (log credit
based on CT)
UV (log credit based
UV dose and oper-
ating within vali-
dated conditions)
Individual filter per-
formance (1.0 log)
Demonstration of Per-
formance
You must submit the following items
Initial demonstration of:
Unconsolidated, predominantly sandy aquifer
Setback distance of at least 25 ft. (0.5 log) or 50 ft. (1 .0 log)
If monthly average of daily max turbidity is greater than 1 NTU
then system must report result and submit an assessment
of the cause
Monthly verification of:
Combined filter effluent (CFE) turbidity levels less than or
equal to 0.15 NTU in at least 95 percent of the 4 hour CFE
measurements taken each month
Initial demonstration of:
Removal efficiency through challenge studies
Methods of challenge studies meet rule criteria
Integrity test results and baseline
Monthly report summarizing:
All direct integrity test results above the control limit and the
corrective action that was taken
All indirect integrity monitoring results triggering direct integrity
testing and the corrective action that was taken
Initial demonstration that the following criteria are met:
Process meets the basic definition of bag or cartridge filtra-
tion;
Removal efficiency established through challenge testing that
meets rule criteria
Challenge test shows at least 2 and 3 log removal for bag and
cartridge filters, respectively
Summary of CT values for each day and log inactivation
based on tables in section IV.C.14
Summary of CT values for each day and log inactivation
based on tables in section IV.C.14
Results from reactor validation testing demonstrating oper-
ating conditions that achieve required UV dose
Monthly report summarizing the percentage of water entering
the distribution system that was not treated by UV reactors
operating within validated conditions for the required UV
dose in section IV.C.15
Monthly verification of the following, based on continuous
monitoring of turbidity for each individual filter:
Filtered water turbidity less than 0.1 NTU in at least 95 per-
cent of the daily maximum values from individual filters (ex-
cluding 15 minute period following start up after
backwashes)
Jo individual filter with a measured turbidity greater than 0.3
NTU in two consecutive measurements taken 15 minutes
apart
Results from testing following State approved protocol
On the following sched-
ule1
(systems serving >10,000
people)
Initial demonstration no
later than 72 months
after promulgation
Report within 30 days fol-
lowing the month in
which the monitoring
was conducted, begin-
ning 72 months after
promulgation
Monthly reporting within
10 days following the
month in which the
monitoring was con-
ducted, beginning on 72
months after promulga-
tion
No later than 72 months.
after promulgation
Within 10 days following
the month in which
monitoring was con-
ducted, beginning 72
months after promulga-
tion
No later than 72 months
after promulgation
Within 10 days following
the month in which
monitoring was con-
ducted, beginning 72
months after promulga-
tion
Within 10 days following
the month in which
monitoring was con-
ducted, beginning 72
months after promulga-
tion
No later than 72 months
after promulgation
Within 10 days following
the month in which
monitoring was con-
ducted, beginning 72
months after promulga-
tion
Monthly reporting within
10 days following the
month in which the
monitoring was con-
ducted, beginning on 72
months after promulga-
tion
'Jo later than 72 months
after promulgation
On the following sched-
ule1
(systems serving < 10,000
people)
Initial demonstration no
later than 102 months
after promulgation.
Report within 30 days fol-
lowing the month in
which the monitoring
was conducted, begin-
ning 102 months after
promulgation.
Monthly reporting: within
10 days following the
month in which the
monitoring was con-
ducted, beginning on
102 months after pro-
mulgation.
No later than 102 months
after promulgation.
Within 10 days following
the month in which
monitoring was con-
ducted, beginning 102
months after promulga-
tion.
No later than 102 months
after promulgation.
Within 10 days following
the month in which
monitoring was con-
ducted, beginning 102
months after promulga-
tion.
Within 10 days following
the month in which
monitoring was con-
ducted, beginning 102
months after promulga-
tion.
No later than 102 months
after promulgation.
Within 10 days following
the month in which
monitoring was con-
ducted, beginning 102
months after promulga-
tion.
Monthly reporting: within
10 days following the
month in which the
monitoring was con-
ducted, beginning 102
months after promulga-
tion.
No later than 102 months
after promulgation.
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Federal Register/Vol. 68, No. 154/Monday, August 11, 2003/Proposed Rules
TABLE IV-34—TOOLBOX REPORTING REQUIREMENTS—Continued
Toolbox option
(potential
Cryptosporidium re-
duction log credit)
You must submit the following items
Monthly verification of operation within State-approved condi-
tions for demonstration of performance credit
On the following sched-
ule1
(systems serving £10,000
people)
Within 10 days following
the month in which
monitoring was con-
ducted, beginning 72
months after promulga-
tion
On the following sched-
ule1
(systems serving < 10,000
people)
Within 10 days following
the month in which
monitoring was con-
ducted, beginning 102
months after promulga-
tion.
1 States may allow an additional two years for systems making capital improvements.
Reporting requirements associated with disinfection profiling and benchmarking are summarized in Table IV-35 for large
systems and in Table IV-36 for small systems.
TABLE IV-35.—DISINFECTION BENCHMARKING REPORTING REQUIREMENTS FOR LARGE SYSTEMS
System type
Benchmark component
Submit the following items
On the following schedule
Systems required to
conduct
Cryptosporidium
monitoring.
Systems not required
to conduct
Cryptosporidium
monitoring1.
Characterization of Disinfection Practices
State Review of Proposed Changes to Dis-
infection Practices.
Applicability
Characterization of Disinfection Practices
State Review of Proposed Changes to Dis-
infection Practices.
Giardia lamblia and virus inactiva-
tion profiles must be on file for
State review during sanitary
survey.
Inactivation profiles and bench-
mark determinations.
None
None
None
No later than 36 months after pro-
mulgation.
Prior to significant modification of
disinfection practice.
None.
None.
None.
1Systems that provide at least 5.5 log of Cryptosporidium treatment consistent with a Bin 4 treatment implication are not required to conduct
Cryptosporidium monitoring.
TABLE IV-36.—DISINFECTION BENCHMARKING REPORTING REQUIREMENTS FOR SMALL SYSTEMS
System type
Benchmark component
Submit the following items
On the following schedule
Systems required to
conduct
Cryptosporidium
monitoring.
Systems not required
to conduct
Cryptosporidium
monitoring and that
exceed DBP trig-
gers 1'2'3.
Characterization of Disinfection Practices
State Review of Proposed Changes to Dis-
infection Practices.
Applicability Period
Systems not required
to conduct
Cryptosporidium
monitoring and that
do not exceed DBP
triggers2'3.
Characterization of Disinfection Practices
State Review of Proposed Changes to Dis-
infection Practices.
Applicability Period
Giardia lamblia and virus inactiva-
tion profiles must be on file for
State review during sanitary
survey.
tnactivation profiles and bench-
mark determinations.
Notify State that profiling is re-
quired based on DBP levels.
Giardia lamblia and virus inactiva-
tion profiles must be on file for
State review during sanitary
survey.
Inactivation profiles and bench-
mark determinations.
Notify State that profiling is not re-
quired based on DBP levels.
Characterization of Disinfection Practices
State Review of Proposed Changes to Dis-
infection Practices.
None
None
No later than 66 months after pro-
mulgation.
Prior to significant modification of
disinfection practice.
No later than 42 months after pro-
mulgation.
No later than 54 months after pro-
mulgation.
Prior to significant modification of
disinfection practice.
No later than 42 months after pro-
mulgation.
None.
None.
1 Systems that provide at least 5.5 log of Cryptosporidium treatment consistent with a Bin 4 treatment implication are not required to conduct
Cryptosporidium monitoring. . „„,..„« , , . „
2|f the E coli annual mean concentration is < 10/100 mL for systems using lakes/reservoir sources or <, 50/100 mL for systems using flowing
stream sources, the system is not required to conduct Cryptosporidium monitoring and will only be required to characterize disinfection practices
if DBP triggers are exceeded.
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Federal Register/Vol. 68, No. 154/Monday, August 11, 2003/Proposed Rules
47731
. 3lf the system is a CWS or NTNCWSs and TTHM or HAA5 levels in the distribution system are at least 0.064 mg/L or 0.048 mg/L, respec-
tively, calculated as an LRAA at any Stage 1 DBPR sampling site, then the system is triggered into disinfection profiling.
4. Request for Comment
EPA requests comment on the
reporting and recordkeeping
requirements proposed for the
LT2ESWTR.
Specifically, the Agency requests
comment on the proposed requirement
that systems report monthly on the use
of microbial toolbox components to
demonstrate compliance with their
Cryptosporidium treatment
requirements. An alternative may be for
systems to keep records on site for State
review instead of reporting the data.
K. Analytical Methods
EPA is proposing to require public
water systems to conduct LT2ESWTR
monitoring using approved methods for
Cryptosporidium, E. coli, and turbidity
analyses. This includes meeting quality
control criteria stipulated by the
approved methods and additional
method-specific requirements, as stated
later in this section. Related
requirements on the use of approved
laboratories are discussed in section
IVX, and proposed requirements for
reporting of data were stated previously
in section IV.J. EPA has developed draft
guidance for sampling and analyses
under the LT2ESWTR (see USEPA
2003g and 2003h). This guidance is
available in draft form in the docket for
today's proposal (http://www.epa.gov/
edocketf).
1. Cryptosporidium
a. What is EPA proposing today?
Method 1622: "Cryptosporidium in
Water by Filtration/IMS/FA" (EPA-821-
R-01-026, April 2001) (USEPA 2001e)
and Method 1623: "Cryptosporidium
and Giardia in Water by Filtration/IMS/
FA" (EPA 821-R-01-025, April 2001)
(USEPA 2001f) are proposed for
Cryptosporidium analysis under this
rule. Methods 1622 and 1623 require
filtration, immunomagnetic separation
(IMS) of the oocysts from the captured
material, and examination based on IFA,
DAPI staining results, and differential
interference contrast (DIG) microscopy
for determination of oocyst
concentrations.
Method Requirements
For each Cryptosporidium sample
under this proposal, all systems must
analyze at least a 10-L sample volume.
Systems may collect and analyze greater
than a 10-L sample volume. If a sample
is very turbid, it may generate a large
packed pellet volume upon
centrifugation (a packed pellet refers to
the concentrated sample after
centrifugation has been performed in
EPA Methods 1622 and 1623). Based on
IMS purification limitations, samples
resulting in large packed pellets will
require that the sample concentrate be
aliquoted into multiple "subsamples"
for independent processing through
IMS, staining, and examination. Because
of the expense of the IMS reagents and
analyst time to examine multiple slides
per sample, systems are not required to
analyze more than 2 mL of packed pellet
volume per sample.
In cases where it is not feasible for a
system to process a 10-L sample for
Cryptosporidium analysis (e.g., filter
clogs prior to filtration of 10 L) the
system must analyze as much sample
volume as can be filtered by 2 filters, up
to a packed pellet volume of 2 mL. This
condition applies only to filters that
have been approved by EPA for
nationwide use with Methods 1622 and
1623—the Pall Gelman Envirochek™
and Envirochek™ HV filters, the IDEXX
Filta-Max™ foam filter, and the
Whatman CrypTest™ cartridge filter.
Methods 1622 and 1623 include
fluorescein isothiocyanate (FITC) as the
primary antibody stain for
Cryptosporidium detection, DAPI
staining to detect nuclei, and DIG to
detect internal structures. For purposes
of the LT2ESWTR, systems must report
total Cryptosporidium oocysts as
detected by FITC as determined by the
color (apple green or alternative stain
color approved for the laboratory under
the Lab QA Program described in
section VI.L), size (4-6 urn) and shape
(round to oval). This total includes all
of the oocysts identified as described
here, less atypical organisms identified
by FITC, DIG, or DAPI (e.g., possessing
spikes, stalks, appendages, pores, one or
two large nuclei filling the cell, red
fluorescing chloroplasts, crystals,
spores, etc.).
Matrix Spike Samples
As required by Method 1622 and
1623, systems must have 1 matrix spike
(MS) sample analyzed for each 20
source water samples. The volume of
the MS sample must be within ten
percent of the volume of the unspiked
sample that is collected at the same
time, and the samples must be collected
by splitting the sample stream or
collecting the samples sequentially. The
MS sample and the associated unspiked
sample must be analyzed by the same
procedure. MS samples must be spiked
and filtered in the laboratory. However,
if the volume of the MS sample is
greater than 10 L, the system is
permitted to filter all but 10 L of the MS
sample in the field, and ship the filtered
sample and the remaining 10 L of source
water to the laboratory. In this case, the
laboratory must spike the remaining 10
L of water and filter it through the filter
used to collect the balance of the sample
in the field.
EPA is proposing to require the use of
flow cytometer-counted spiking
suspensions for spiked QC samples
during the LT2ESWTR. This provision
is based on the improved precision
expected for spiking suspensions
counted with a flow cytometer, as
compared to those counted using well
slides or hemacytometers. During the
Information Collection Rule
Supplemental Surveys, the mean
relative standard deviation (RSD) across
25 batches of flow cytometer-sorted
Cryptosporidium spiking suspensions
was 1.8%, with a median of 1.7%
(Connell et a}. 2000). In EPA
Performance Evaluation (PE) studies,
the mean RSD for flow cytometer sorted
Cryptosporidium spiking suspensions
was 3.4%. In comparison, the mean RSD
for Cryptosporidium spiking
suspensions enumerated manually by
20 laboratories using well slides or
hemacytometers was 17% across 108
rounds of 10-replicate counts.
QC requirements in Methods 1622
and 1623 must be met by laboratories
analyzing Cryptosporidium samples
under the LT2ESWTR. The QC
acceptance criteria are the same as
stipulated in the method. For the initial
precision and recovery (IPR) test, the
mean Cryptosporidium recovery must
be 24% to 100% with maximum relative
standard deviation (i.e., precision) of
55%. For each ongoing precision and
recovery (OPR) sample, recovery must
be in the range of 11% to 100%. For
each method blank, oocysts must be
undetected.
Methods 1622 and 1623 are
performance-based methods and,
therefore, allow multiple options to
perform the sample processing steps in
the methods if a laboratory can meet
applicable QC criteria and uses the same
determinative technique. If a laboratory
uses the same procedures for all
samples, then all field samples and QC
samples must be analyzed in that same
manner. However, if a laboratory uses
more than one set of procedures for
CTyptosporidium analyses under
LT2ESWTR then the laboratory must
analyze separate QC samples for each
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Federal Register/Vol. 68, No. 154/Monday. August 11, 2003/Proposed Rules
option to verify compliance with the QC
criteria. For example, if the laboratory
analyzes samples using both the
Envirochek™ and Filta-Max™ filters, a
separate set of IPR, OPR, method blank,
and MS samples must be analyzed for
each filtration option.
b. How was this proposal developed?
EPA is proposing EPA Methods 1622
and 1623 for Cryptosporidium analyses
under the LT2ESWTR because these are
the best available methods that have
undergone full validation testing. In
addition, these methods have been used
successfully in a national source water
monitoring program as part of the
Information Collection Rule
Supplemental Surveys (ICRSS). The
minimum sample volume and other
quality control requirements are
intended to ensure that data are of
sufficient quality to assign systems to
LT2ESWTR risk bins. Further, the
proposed method requirements for
analysis of Cryptosporidium are
consistent with recommendations by the
Stage 2 M-DBP Advisory Committee. In
the Agreement in Principle, the
Committee recommended that source
water Cryptosporidium monitoring
under the LT2ESWTR be conducted
using EPA Methods 1622 and 1623 with
no less than 10 L samples. EPA also has
proposed these methods for approval for
ambient water monitoring under
Guidelines Establishing Test Procedures
for the Analysis of Pollutants;
Analytical Methods for Biological
Pollutants in Ambient Water (66 FR
45811, August 30, 2001) (USEPA 2001i).
When considering the method
performance that could be achieved for
analysis of Cryptosporidium under the
LT2ESWTR, EPA and the Advisory
Committee evaluated the
Cryptosporidium recoveries reported for
Methods 1622 and 1623 in the ICRSS.
As described in section III.C, the ICRSS
was a national monitoring program that
involved 87 utilities sampling twice per
month over 1 year for Cryptosporidium
and other microorganisms and water
quality parameters. During the ICRSS,
the mean recovery and relative standard
deviation associated with enumeration
of MS samples for total oocysts by
Methods 1622 and 1623 were 43% and
47%, respectively (Connell et al. 2000).
EPA believes that with provisions like
the Laboratory QA Program for
Cryptosporidium laboratories (see
section IV.L), comparable performance
to that observed in the ICRSS can be
achieved in LT2ESWTR monitoring
with the use of Methods 1622 and 1623,
and that this level of performance will
be sufficient to realize the public health
goals intended by EPA and the Advisory
Committee for the LT2ESWTR. Other
methods would need to achieve
comparable performance to be
considered for use under the
LT2ESWTR. For example, EPA does not
expect the Information Collection Rule
Method, which resulted in 12% mean
recovery for MS samples during the
Information Collection Rule Laboratory
Spiking Program (Scheller, 2002), to
meet LT2ESWTR data quality
objectives.
For systems collecting samples larger
than 10 L, EPA is proposing the
approach of allowing systems to filter
all but 10 L of the corresponding MS
sample in the field, and ship the filtered
sample and the remaining 10 L of source
water to the laboratory for spiking and
analysis. The Agency has determined
that the added costs associated with
shipping entire high-volume (e.g. 50-L)
samples to a laboratory for spiking and
analysis are not merited by improved
data quality relative to the use of
Cryptosporidium MS data under the
LT2ESWTR. EPA estimates that the
average cost for shipping a 50-L bulk
water sample is $350 more than the cost
of shipping a 10-L sample and a filter.
A study comparing these two
approaches (i.e., spiking and filtering 50
L vs. field filtering 40 L and spiking 10
L) indicated that spiking the 10-L
sample produced somewhat higher
recoveries (USEPA 2003i). However, the
differences were not significant enough
to offset the greatly increased shipping
costs, given the limited use of MS data
in LT2ESWTR monitoring.
c. Request for comment. EPA requests
comment on the proposed method
requirements for Cryptosporidium
analysis, including the following
specific issues:
Minimum Sample Volume
It is the intent of EPA that LT2ESWTR
sampling provide representative annual
mean source water concentrations. If
systems were unable to analyze an
entire sample volume during certain
periods of the year due to elevated
turbidity or other water quality factors,
this could result in systems analyzing
different volumes in different samples.
Today's proposal requires systems to
analyze at least 10 L of sample or the
maximum amount of sample that can be
filtered through two filters, up to a
packed pellet volume of 2 mL. EPA
requests comment on whether these
requirements are appropriate for
systems with source waters that are
difficult to filter or that generate a large
packed pellet volume. Alternatively,
systems could be required to filter and
analyze at least 10 L of sample with no
exceptions.
Approval of Updated Versions of EPA
Methods 1622 and 1623
EPA has developed draft revised
versions of EPA Methods 1622 and 1623
in order to consolidate several method-
related changes EPA believes may be
necessary to address LT2ESWTR
monitoring requirements (see USEPA
2003J and USEPA 2003k). EPA is
requesting comment on whether these
revised versions should be approved for
monitoring under the LT2ESWTR,
rather than the April 2001 versions
proposed in today's rule. If the revised
versions were approved, previously
collected data generated using the
earlier versions of the methods would
still be acceptable for grandfathering,
provided the other criteria described in
section IV.A.l.d were met. Drafts of the
updated methods are provided in the
docket for today's rule, and differences
between these versions and the April
2001 versions of the methods are clearly
indicated for evaluation and comment.
Changes to the methods include the
following:
(1) Increased flexibility in matrix spike
(MS) and initial precision and recovery (IPR)
requirements—the requirement that the
laboratory must analyze an MS sample on the
first sampling event for a new PWS would be
changed to a recommendation; the revised
method would allow the IPR test to be
performed across four different days, rather
than restrict analyses to 1 day;
(2) Clarification of some method
procedures, including the spiking suspension
vortexing procedure and the buffer volumes
used during immunomagnetic separation
(IMS); requiring (rather than recommending)
that laboratories purchase HC1 and NaOH
standards at the normality specified in the
method; and clarification that the use of
methanol during slide staining in section
14.2 of the method is as per manufacturer's
instructions;
(3) Additional recommendations for
minimizing carry-over of debris onto
microscope slides after IMS and information
on microscope cleaning;
(4) Clarification in the method of the
actions to take in the event of QC failures,
such as that any positive sample in a batch
associated with an unacceptable method
blank is unacceptable and that any sample in
a batch associated with an unacceptable
ongoing precision and recovery (OPR) sample
is unacceptable;
(5) Changes to the sample storage and
shipping temperature to "less than 10°C and
not frozen", and additional guidance on
sample storage and shipping procedures that
addresses time of collection, and includes
suggestions for monitoring sample
temperature during shipment and upon
receipt at the laboratory.
(6) Additional analyst verification
procedures—adding examination using
differential interference contrast (DIG)
microscopy to the analyst verification
requirements.
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Federal Register/Vol. 68, No, 154/Monday, August 11, 2003/Proposed Rules
47733
(7) Addition of an approved method
modification using the Pall Gelman
Envirochek HV filter. This approval was
based on an interlaboratory validation study
demonstrating that three laboratories, each
analyzing reagent water and a different
source water, met all method acceptance
criteria for Cryptosporidium. EPA issued a
letter (dated March 21, 2002) under the
Alternative Test Procedures program
approving the procedure as an acceptable
version of Method 1623 for Cryptosporidium
(but not for Giardia). EPA also noted in the
letter that the procedure was considered to be
an acceptable modification of EPA Method
1622.
(8) Incorporation of detailed procedures for
concentrating samples using an IDEXX Filta-
Max™ foam filter. A method modification
using this filter already is approved by EPA
in the April 2001 versions of the methods.
(9) Addition of BTP EasySeed™ irradiated
oocysts and cysts as acceptable materials for
spiking routine QC samples. EPA approved
the use of EasySeed™ based on side-by-side
comparison tests of method recoveries using
EasySeed™ and live, untreated organisms.
EPA issued a letter (dated August 1, 2002)
approving EasySeed™ for use in routine QC
samples for EPA Methods 1622 and 1623 and
for demonstrating comparability of method
modifications in a single laboratory.
(10) Removal of the Whatman Nuclepore
CrypTest™ cartridge filter. Although a
method modification using this filter was
approved by EPA in the April 2001 versions
of (he methods, the filter is no longer
available from the manufacturer, and so is no
longer an option for sample filtration.
The changes in the June 2003 draft
revisions of EPA Methods 1622 and
1623 reflect method-related
clarifications, modifications, and
additions that EPA believes should be
addressed for LT2ESWTR
Cryptosporidium monitoring.
Alternatively, these issues could be
addressed through regulatory
requirements in the final LT2ESWTR
(for required changes and additions) and
through guidance (for recommended
changes and clarifications). However,
EPA believes that addressing these
issues through a single source in
updated versions of EPA Methods 1622
and 1623 (which could be approved in
the final LT2ESWTR) may be more
straightforward and easier for systems
and laboratories to follow than
addressing them in multiple sources
(i.e., existing methods, the final rule,
and laboratory guidance).
2. E. coli
a. What is EPA proposing today? For
enumerating source water E. coli density
under the LT2ESWTR, EPA is proposing
to approve the same methods that were
proposed by EPA under Guidelines
Establishing Test Procedures for the
Analysis of Pollutants; Analytical
Methods for Biological Pollutants in
Ambient Water (66 FR 45811, August
30, 2001) (USEPA 2001i). These
methods are summarized in Table IV-
37. Methods are listed within the
general categories of most probable
number tests and membrane filtration
tests. Method identification numbers are
provided for applicable standards
published by EPA and voluntary
consensus standards bodies (VCSB)
including Standard Methods, American
Society of Testing Materials (ASTM),
and the Association of Analytical
Chemists (AOACJ.
TABLE IV-37.— PROPOSED METHODS FOR E. COLI ENUMERATION 1
Technique
(MPN).
Method1
LTB, EC-MUG
ONPG-MUG
ONPG-MUG
mFC-*NA-MUG
mENDO or LES-
ENDO-NA-MUG.
m-ColiBlue24 broth
EPA
1103 1
1603
1604
Standard
methods2
9221B.1/
9221 F
9223B
9223B
9222D/
9222G
9222B/
9222G
921 3D
VCSB methods
ASTM3
D5392 93
AOAC4
991 15
Commercial example
m-ColiBlue246.
1 Tests must be conducted in a format that provides organism enumeration.
2Standard Methods for the Examination of Water and Wastewater. American Public Health Association. 20th, 19th, and 18th Editions. Amer
Publ. Hlth. Assoc., Washington, DC.
3Annuai Book of ASTM Standards—Water and Environmental Technology. Section 11.02. ASTM. 100 Barr Harbor Drive, West
Conshohocken, PA 19428.
4Official Methods of Analysis of AOAC International, 16th Edition, Volume I, Chapter 17. AOAC international. 481 North Frederick Avenue
Suite 500, Gaithersburg, Maryland 20877-2417.
5 Manufactured by IDEXX Laboratories, Inc., One tDEXX Drive, Westbrook, Maine 04092.
6 Manufactured by Hach Company, 100 Dayton Aye., Ames, IA 50010.
7 Acceptable version of method approved as a drinking water alternative test procedure.
EPA is proposing to allow a holding
time of 24 hours for E. coli samples. The
holding time refers to the time between
sample collection and initiation of
analysis. Currently, 40 CFR 141.74(a)
limits the holding time for source water
coliform samples to 8 hours and
requires that samples be kept below
10°C during transit. EPA believes that
new studies, described later in this
section, demonstrate that E. coli analysis
results for samples held for 24 hours
will be comparable to samples held for
8 hours, provided the samples are held
below 10°C and are not allowed to
freeze. This proposed increase in
holding time is significant for the
LT2ESWTR because typically it is not
feasible for systems to meet an 8-hour
holding time when samples cannot be
analyzed on-site. Many small systems
that will conduct E. coli monitoring
under the LT2ESWTR lack a certified
on-site laboratory for E. coli analyses
and will be required to ship samples to
a certified laboratory. EPA believes that
it is feasible for these systems to comply
with a 24 hour holding time for E. coli
samples through using overnight
delivery services.
b. How was this proposal developed?
As noted, EPA recently proposed
methods for ambient water E. coli
analysis under Guidelines Establishing
Test Procedures for the Analysis of
Pollutants; Analytical Methods for
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Federal Register/Vol. 68, No. 154/Monday, August 11. 2003/Proposed Rules
Biological Pollutants in Ambient Water
(66 FR 45811, August 30, 2001) (USEPA
2001i). These proposed methods were
selected based on data generated by EPA
laboratories, submissions to the
alternate test procedures (ATP) program
and voluntary consensus standards
bodies, published peer reviewed journal
articles, and publicly available study
reports.
The source water analysis for E. coli
that will be conducted under the
LT2ESWTR is similar to the type of
ambient water analyses for which these
methods were previously proposed (66
FR 45811, August 30, 2001) (USEPA
2001i). EPA continues to support the
findings of this earlier proposal and
believes that these methods have the
necessary sensitivity and specificity to
meet the data quality objectives of the
LT2ESWTR.
New Information on E. coli Sample
Holding Time
It is generally not feasible for systems
that must ship E. coli samples to an off-
site laboratory to comply with an 8-hour
holding time requirement. During the
ICRSS, 100% of the systems that
shipped samples off-site for E. coli
analysis exceeded the 8 hour holding
time; 12% of these samples had holding
times in excess of 30 hours. Most large
systems that will be required to monitor
for E. coli under the LT2ESWTR could
conduct these analyses on-site, but
many small systems will need to ship
samples off-site to a certified contract
laboratory.
EPA participated in three phases of
studies to assess the effect of increased
sample holding time on E. coli analysis
results. These are summarized as
follows, and are described in detail in
Pope et al (2003).
• Phase 1-EPA, the Wisconsin State
Laboratory of Hygiene (WSLH), and
DynCorp conducted a study to evaluate
E. coli sample concentrations from four
sites at 8, 24, 30, and 48 hours after
sample collection for samples stored at
4°G, 10°C, 20°C, and 35°C. Temperature
was varied to assess the effect of
different shipping conditions. Samples
were analyzed in triplicate by
membrane filtration (mFC followed by
transfer to NA-MUG) and Colilert
(Quanti-Tray 2000} (Pope eta]. 2003).
• Phase 2-EPA conducted a study to
evaluate E, coli sample concentrations
from seven sites at 8, 24, 30, and 48
hours after sample collection for
samples stored in coolers containing
wet ice or Utek ice packs (to assess real-
world storage conditions). Samples were
analyzed in triplicate by membrane
filtration (mFC followed by transfer to
NA-MUG) and Colilert (Quanti-Tray
2000) (Pope et al. 2003).
• Phase 3-EPA, through cooperation
with AWWA, obtained E. coli holding
time data from ten drinking water
utilities that evaluated samples from 12
source waters. Each utility used an E.
coli method of its choice (Colilert,
mTEC, mEndo to NA-MUG, or mFC to
NA-MUG). Samples were stored in
coolers with wet ice, Utek ice packs, or
Blue ice (Pope et al. 2003}.
Phase 1 results indicated that E, coli
concentrations were not significantly
different after 24 hours at most sites
when samples were stored at lower
temperatures. Results from Phase 2,
which evaluated actual sample storage
practices, verified the Phase 1
observations at most sites. Similar
results were observed during Phase 3,
which evaluated a wider variety of
surface waters from different regions
throughout the U.S. During Phase 3, E.
coli concentrations were not
significantly different after 24 hours at
most sites when samples were
maintained below 10°C and did not
freeze during storage. At longer holding
times (e.g., 48 hours), larger differences
were observed.
Based on these studies, EPA has
concluded that E. coli samples can be
held for up to 24 hours prior to analysis
without compromising the data quality
objectives of LT2ESWTR E. coli
monitoring. Further, EPA believes that it
is feasible for systems that must ship E.
coli samples to an off-site laboratory for
analysis to meet a 24 hour holding time.
EPA is developing guidance for systems
on packing and shipping E. coli samples
so that samples are maintained below
10°C and not allowed to freeze (USEPA
2003g). This guidance is available in
draft in the docket for today's proposal
(h tip://www. epa.gov/edocket/).
c. Bequest for comment. EPA requests
comment on whether the E. coli
methods proposed for approval under
the LT2ESWTR are appropriate, and
whether there are additional methods
not proposed that should be considered.
Comments concerning method approval
should be accompanied by supporting
data where possible.
EPA also requests comment on the
proposal to extend the holding time for
E. coli source water sample analyses to
24 hours, including any data or other
information that would support, modify,
or repudiate such an extension. Should
EPA limit the extended holding time to
only those E. coli analytical methods
that were evaluated in the holding time
studies noted in this section? The
results in Pope et al. (2003) indicate that
most E. coli samples analyzed using
ONPG-MUG (see methods in Table IV-
37) incurred no significant degradation
after a 30 to 48 hour holding time. As
a result, should EPA increase the source
water E. coli holding time to 30 or 48
hours for samples evaluated by ONPG-
MUG, and retain a 24-hour holding time
for samples analyzed by other methods?
EPA also requests comment on the cost
and availability of overnight delivery
services for E. coli samples, especially
in rural areas.
3. Turbidity
a. What is EPA proposing today? For
turbidity analyses that will be
conducted under the LT2ESWTR, EPA
is proposing to require systems to use
the analytical methods that have been
previously approved by EPA for
analysis of turbidity in drinking water,
as listed in 40 CFR Part 141.74. These
are Method 2130B as published in
Standard Methods for the Examination
of Water and Wastewater (APHA 1992),
EPA Method 180.1 (USEPA 1993), and
Great Lakes Instruments Method 2
(Great Lakes Instruments, 1992), and
Hach FilterTrak Method 10133.
EPA method 180-1 and Standard
Method 2130B are both nephelometric
methods and are based upon a
comparison of the intensity of light
scattered by the sample under defined
conditions with the intensity of light
scattered by a standard reference
suspension. Great Lakes Instruments
Method 2 is a modulated four beam
infrared method using a ratiometric
algorithm to calculate the turbidity
value from the four readings that are
produced. Hach Filter Trak (Method
10133) is a laser-based nephelometric
method used to determine the turbidity
of finished drinking waters.
Turbi dimeters
Systems are required to use
turbidimeters described in EPA-
approved methods for measuring
turbidity. For regulatory reporting
purposes, either an on-line or a bench
top turbidimeter can be used. If a system
chooses to use on-line units for
monitoring, the system must validate
the continuous measurements for
accuracy on a regular basis using a
protocol approved by the State.
b. How was this proposal developed?
EPA believes the currently approved
methods for analysis of turbidity in
drinking water are appropriate for
turbidity analyses that will be
conducted under the LT2ESWTR.
c. Request for comment. EPA requests
comment on whether the turbidity
methods proposed today for the
LT2ESWTR should be approved, and
whether there are additional methods
not proposed that should be approved.
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L. Laboratory Approval
Given the potentially significant
implications in terms of both cost and
public health protection of microbial
monitoring under the LT2ESWTR,
laboratory analyses for
Cryptosporidium, E. coli, and turbidity
must be accurate and reliable within the
limits of approved methods. Therefore,
EPA proposes to require public water
systems to use laboratories that have
been approved to conduct analyses for
these parameters by EPA or the State.
The following criteria are proposed for
laboratory approval under the
LT2ESWTR:
* For Cryptosporidium analyses
under the LT2ESWTR, EPA proposes to
approve laboratories that have passed a
quality assurance evaluation under
EPA's Laboratory Quality Assurance
Evaluation Program (Lab QA Program)
for Analysis of Cryptosporidium in
Water (described in 67 FR 9731, March
4, 2002) (USEPA 2002c). If States adopt
an equivalent approval process under
State laboratory certification programs,
then systems can use laboratories
approved by the State.
• For E. coli analyses, EPA proposes
to approve laboratories that have been
certified by EPA, the National
Environmental Laboratory Accreditation
Conference, or the State for total
coliform or fecal coliform analysis in
source water under 40 CFR 141.74. The
laboratory must use the same analytical
technique for E. coli that the laboratory
uses for total coliform or fecal coliform
analysis under 40 CFR 141.74.
• Turbidity analyses must be
conducted by a person approved by the
State for analysis of turbidity in
drinking water under 40 CFR 141.74.
These criteria are further described in
the following paragraphs.
1. Cryptosporidium Laboratory
Approval
Because States do not currently
approve laboratories for
Cryptosporidium analyses and
LT2ESWTR monitoring will begin 6
months after rule promulgation, EPA
will initially assume responsibility for
Cryptosporidium laboratory approval.
EPA expects, however, that States will
include Cryptosporidium analysis in
their State laboratory certification
programs in the future. EPA has
established the Lab QA Program for
Cryptosporidium analysis to identify
laboratories that can meet LT2ESWTR
data quality objectives. This is a
voluntary program open to laboratories
involved in analyzing Cryptosporidium
in water. Under this program, EPA
assesses the ability of laboratories to
reliably measure Cryptosporidium
occurrence with EPA Methods 1622 and
1623, using both performance testing
samples and an on-site evaluation.
EPA initiated the Lab QA Program for
Cryptosporidium analysis prior to
promulgation of the LT2ESWTR to
ensure that adequate sample analysis
capacity will be available at qualified
laboratories to support the required
monitoring. The Agency is monitoring
sample analysis capacity at approved
laboratories through the Lab QA
Program, and does not plan to
implement LT2ESWTR monitoring until
the Agency determines that there is
adequate laboratory capacity. In
addition, utilities that choose to conduct
Cryptosporidium monitoring prior to
LT2ESWTR promulgation with the
intent of grandfathering the data may
elect to use laboratories that have
passed the EPA quality assurance
evaluation.
Laboratories seeking to participate in
the EPA Lab QA Program for
Cryptosporidium analysis must submit
an interest application to EPA,
successfully analyze a set of initial
performance testing samples, and
undergo an on-site evaluation. The on-
site evaluation includes two separate
but concurrent assessments: (1)
Assessment of the laboratory's sample
processing and analysis procedures,
including microscopic examination, and
(2) evaluation of the laboratory's
personnel qualifications, quality
assurance/quality control program,
equipment, and recordkeeping
procedures.
Laboratories that pass the quality
assurance evaluation will be eligible for
approval for Cryptosporidium analysis
under the LT2ESWTR. The Lab QA
Program is described in detail in a
Federal Register Notice (67 FR 9731,
March 4, 2002) (USEPA 2002c) and
additional information can be found
online at: www.epa.gov/safewater/h2/
cla_int.html.
Laboratories in the Lab QA Program
will receive a set of three ongoing
proficiency testing (OPT) samples
approximately every four months. EPA
will evaluate the precision and recovery
data for OPT samples to determine if the
laboratory continues to meet the
performance criteria of the Laboratory
QA Program.
2. E. coli Laboratory Approval
Pubic water systems are required to
have samples analyzed for E. coli by
laboratories certified under the State
drinking water certification program to
perform total coliform and fecai
coliform analyses under 40 CFR 141.74.
EPA is proposing that the general
analytical techniques the laboratory is
certified to use under the drinking water
certification program (e.g., membrane
filtration, multiple-well, multiple-tube)
will be the methods the laboratory can
use to conduct E. coli source water
analyses under the LT2ESWTR.
3. Turbidity Analyst Approval
Measurements of turbidity must be
conducted by a party approved by the
State. This is consistent with current
requirements for turbidity
measurements in drinking water (40
CFR 141.74).
4. Request for Comment
EPA requests comment on the
laboratory approval requirements
proposed today, including the following
specific issues:
Analyst Experience Criteria
The Lab QA Program, which EPA will
use to approve laboratories for
Cryptosporidium analyses under the
LT2ESWTR, includes criteria for analyst
experience. Principal analyst/
supervisors (minimum of one per
laboratory) should have a minimum of
one year of continuous bench
experience with Cryptosporidium and
immunofluorescent assay (IFA)
microscopy, a minimum of six months
experience using EPA Method 1622
and/or 1623, and a minimum of 100
samples analyzed using EPA Method
1622 and/or 1623 (minimum 50 samples
if the person was an analyst approved
to'conduct analysis for the Information
Collection Rule Protozoan Method) for
the specific analytical procedure they
will be using.
Under the Lab QA Program, other
analysts (no minimum number of
analysts per laboratory) should have a
minimum of six months of continuous
bench experience with Cryptosporidium
and IFA microscopy, a minimum of
three months experience using EPA
Method 1622 and/or 1623, and a
minimum of 50 samples analyzed using
EPA Method 1622 and/or 1623
(minimum 25 samples if the person was
an analyst approved to conduct analysis
for the Information Collection Rule
Protozoan Method) for the specific
analytical procedures they will be using.
The Lab QA Program criteria for
principal analyst/supervisor experience
are more rigorous than those in Methods
1622 and 1623, which are as follows:
the analyst must have at least 2 years of
college lecture and laboratory course
work in microbiology or a closely
related field. The analyst also must have
at least 6 months of continuous bench
experience with environmental protozoa
detection techniques and IFA
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microscopy, and must have successfully
analyzed at least 50 water and/or
wastewater samples for
Cryptosporidium. Six months of
additional experience in the above areas
may be substituted for two years of
college.
In seeking approval for an Information
Collection Request, EPA requested
comment on the Lab QA Program (67 FR
9731, March 4, 2002} (USEPA 2002c). A
number of commenters stated that the
analyst qualification criteria are
restrictive and could make it difficult
for laboratories to maintain adequate
analyst staffing (and, hence, sample
analysis capacity) in the event of staff
turnover or competing priorities. Some
commenters suggested that laboratories
and analysts should be evaluated based
on proficiency testing, and that analyst
experience standards should be reduced
or eliminated. (Comments are available
in Office of Water docket, number W-
01-17).
Another aspect of the analyst
experience criteria is that systems may
generate Cryptosporidium data for
grandfathering under the LT2ESWTR
using laboratories that meet the analyst
experience requirement of Methods
1622 or 1623 but not the more rigorous
principal analyst/supervisor experience
requirement of the Lab QA Program.
EPA requests comment on whether
the criteria for analyst experience in the
Lab QA Program are necessary, whether
systems are experiencing difficulty in
finding laboratories that have passed the
Lab QA Program to conduct
Cryptosporidium analysis, and whether
any of the Lab QA Program criteria
should be revised to improve the
LT2ESWTR lab approval process.
State Programs To Approve Laboratories
for Cryptosporidium Analysis
Under today's proposal, systems must
have Cryptosporidium samples analyzed
by a laboratory approved under EPA's
Lab QA Program, or an equivalent State
laboratory approval program. Because
States do not currently approve
laboratories for Cryptosporidium
analyses, EPA will initially assume
responsibility for Cryptosporidium
laboratory approval. EPA expects,
however, that States will adopt
equivalent approval programs for
Cryptosporidium analysis under State
laboratory certification programs. EPA
requests comment on how to establish
that a State approval program for
Cryptosporidium analysis is equivalent
to the Lab QA Program.
Specifically, should EPA evaluate
State Approval programs to determine if
they are equivalent to the Lab QA
Program? EPA also requests comment
on the elements that would constitute
an equivalent State approval program
for Cryptosporidium analyses, including
the following: (1) Successful analysis of
initial and ongoing blind proficiency
testing samples prepared using flow
cytometry, including a matrix and
meeting EPA's pass/fail criteria
(described in USEPA 2002c); (2) an on-
site evaluation of the laboratory's
sample processing and analysis
procedures, including microscopic
examination skills, by auditors who
meet the qualifications of a principal
analyst as set forth in the Lab QA
Program (described in USEPA 2002c);
(3) an on-site evaluation of the
laboratory's personnel qualifications,
quality assurance/quality control
program, equipment, and recordkeeping
procedures; (4) a data audit of the
laboratories' QC data and monitoring
data; and (5) use of the audit checklist
used in the Lab QA Program or
equivalent.
M. Requirements for Sanitary Surveys
Conducted by EPA
1. Overview
In today's proposal, EPA is requesting
comment on establishing requirements
for public water systems with
significant deficiencies as identified in
a sanitary survey conducted by EPA
under-SDWA section 1445. These
requirements would apply to surface
water systems for which EPA is
responsible for directly implementing
national primary drinking water
regulations (i.e., systems not regulated
by States with primacy). As described in
this section, these requirements would
ensure that systems in non-primacy
States, currently Wyoming, and systems
not regulated by States, such as Tribal
systems, are subject to standards for
sanitary surveys similar to those that
apply to systems regulated by States
with primacy.
2. Background
As established by the IESWTR in 40
CFR 142.16(b)(3), primacy States must
conduct sanitary surveys for all surface
water systems no less frequently than
every three years for community water
systems and no less frequently than
every five years for noncommunity
water systems. The sanitary survey is an
onsite review and must address the
following eight components: (1) Source,
(2} treatment, (3) distribution system, (4)
finished water storage, (5) pumps, pump
facilities, and controls, (6) monitoring,
reporting, and data verification, (7)
system management and operation, and
(8) operator compliance with State
requirements.
Under the IESWTR, primacy States
are required to have the appropriate
rules or other authority to assure that
systems respond in writing to
significant deficiencies outlined in
sanitary survey reports no later than 45
days after receipt of the report,
indicating how and on what schedule
the system will address significant
deficiencies noted in the survey (40 CFR
142.16(b)(l)(ii)). Further, primacy States
must have the authority to assure that
systems take necessary steps to address
significant deficiencies identified in
sanitary survey reports if such
deficiencies are within the control of the
system and its governing body (40 CFR
142.16(b)(l)(iii)). The IESWTR did not
define a significant deficiency, but
required that primacy States describe in
their primacy applications how they
will decide whether a deficiency
identified during a sanitary survey is
significant for the purposes of the
requirements stated in this paragraph
(40CFRl42.16(b)(3)(v)).
EPA conducts sanitary surveys under
SDWA section 1445 for public water
systems not regulated by primacy States
(e.g., Tribal systems, Wyoming).
However, EPA does not have the
authority required of primacy States
under 40 CFR 142 to ensure that
systems address significant deficiencies
identified during sanitary surveys.
Consequently, the sanitary survey
requirements established by the
IESWTR create an unequal standard.
Systems regulated by primacy States are
subject to the States' authority to require
correction of significant deficiencies
noted in sanitary survey reports, while
systems for which EPA has direct
implementation authority do not have to
meet an equivalent requirement.
3. Request for Comment
In order to ensure that systems for
which EPA has direct implementation
authority address significant
deficiencies identified during sanitary
surveys, EPA requests comment on
establishing either or both of the
following requirements under 40 CFR
141 as part of the NPDWR established
in the final LT2ESWTR:
(1) For sanitary surveys conducted by EPA
under SDWA section 1445, systems would be
required to respond in writing to significant
deficiencies outlined in sanitary survey
reports no later than 45 days after receipt of
the report, indicating how and on what
schedule the system will address significant
deficiencies noted in the survey.
(2) Systems would be required to correct
significant deficiencies identified in sanitary
survey reports if such deficiencies are within
the control of the system and its governing
body.
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47737
For the purposes of these
requirements, a sanitary survey, as
conducted hy EPA, is an onsite review
of the water source (identifying sources
of contamination by using results of
source water assessments where
available), facilities, equipment,
operation, maintenance, and monitoring
compliance of a public water system to
evaluate the adequacy of the system, its
sources and operations, and the
distribution of safe drinking water. A
significant deficiency includes a defect
in design, operation, or maintenance, or
a failure or malfunction of the sources,
treatment, storage, or distribution
system that EPA determines to be
causing, or has the potential for causing
the introduction of contamination into
the water delivered to consumers.
V. State Implementation
This section describes the regulations
and other procedures and policies States
will be required to adopt to implement
the LT2ESWTR, if finalized as proposed
today. States must continue to meet all
other conditions of primacy in 40 CFR
Part 142.
The Safe Drinking Water Act (Act)
establishes requirements that a State or
eligible Indian tribe must meet to
assume and maintain primary
enforcement responsibility (primacy) for
its public water systems. These
requirements include: (1) Adopting
drinking water regulations that are no
less stringent than Federal drinking
water regulations, (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 under the
Act, and (5) adopting and being capable
of implementing an adequate plan for
the provisions 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
basic primacy requirements specified in
40 CFR Part 142, States may be required
to adopt special primacy provisions
pertaining to specific regulations where
implementation of the rule involves
activities beyond general primacy
provisions. States must include these
regulation specific provisions in an
application for approval of their
program revision. Primacy requirements
for today's proposal are discussed
below.
To implement the proposed
LT2ESWTR, States will be required to
adopt revisions to:
§141.2—Definitions
§ 141.71—Criteria for avoiding filtration
§ 141.153—Content of the reports
§ 141.170—Enhanced filtration and
disinfection
Subpart Q—Public Notification
New Subpart W—Additional treatment
technique requirements for
Cryptosporidium
§ 142.14—Records kept by States
§ 142.15—Reports by States
§ 142.16—Special primacy requirements
A. Special State Primacy Requirements
To ensure that a State program
includes all the elements necessary for
an effective and enforceable program
under today's rule, a State primacy
application must include a description
of how the State will perform the
following:
(1) Approve watershed control
programs for the 0.5 log watershed
control program credit in the microbial
toolbox (see section IV.C.2);
(2) Assess significant changes in the
watershed and source water as part of
the sanitary survey process and
determine appropriate follow-up action
(see section IV.AJ;
(3) Determine that a system with an
uncovered finished water storage
facility has a risk mitigation plan that is
adequate for purposes of waiving the
requirement to cover the storage facility
or treat the effluent (see section IV.E);
(4) Approve protocols for removal
credits under the Demonstration of
Performance toolbox option (see section
IV.C.17) and for site specific chlorine
dioxide and ozone CT tables (see section
IV.C.14); and
(5) Approve laboratories to analyze for
Cryptosporidium.
Note that a State program can be
more, but not less, stringent than
Federal regulations. As such, some of
the elements listed here may not be
applicable to a specific State program.
For example, if a State chooses to
require all finished water storage
facilities to be covered or provide
treatment and not to allow a risk
mitigation plan to substitute for this
requirement, then the description for
item (3) would be inapplicable.
B. State Recordkeeping Requirements
The current regulations in § 142.14
require States with primacy to keep
various records, including the
following: Analytical results to
determine compliance with MCLs,
MRDLs, and treatment technique
requirements; system inventories; State
approvals; enforcement actions; and the
issuance of variances and exemptions.
The proposed LT2ESWTR will require
States to keep additional records of the
following, including all supporting
information and an explanation of the
technical basis for each decision:
• Results of source water E. coli and
Cryptosporidium monitoring;
• Cryptosporidium bin classification
for each filtered system, including any
changes to initial bin classification
based on review of the watershed during
sanitary surveys or the second round of
monitoring;
• Determination of whether each
unfiltered system has a mean source
water Cryptosporidium level above 0.01
oocysts/L;
• The treatment processes or control
measures that each system employs to
meet Cryptosporidium treatment
requirements under the LT2ESWTR;
this includes documentation to
demonstrate compliance with required
design and implementation criteria for
receiving credit for microbial toolbox
options, as specified in section IV.C;
• A list of systems required to cover
or treat the effluent of an uncovered
finished water storage facilities; and
• A list of systems for which the State
has waived the requirement to cover or
treat the effluent of an uncovered
finished water storage facility, along
with supporting documentation of the
risk mitigation plan.
C. State Reporting Requirements
EPA currently requires in § 142,15
that States report to EPA information
such as violations, variance and
exemption status, and enforcement
actions. The LT2ESWTR, as proposed,
will add additional reporting
requirements in the following area;
• The Cryptosporidium bin
classification for each filtered system,
including any changes to initial bin
classification based on review of the
watershed during sanitary surveys or
, the second round of monitoring;
• The determination of whether each
unfiltered system has a mean source
water Cryptosporidium level above 0.01
oocysts/L, including any changes to this
determination based on the second
round of monitoring.
D. Interim Primacy
On April 28, 1998, EPA amended its
State primacy regulations at 40 CFR
142.12 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 (63
FR 23362, April 28, 1998) (USEPA
1998f). The new process grants interim
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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 final determination. However,
this interim primacy authority is only
available to a State that has primacy
(including interim primacy) for every
existing NPDWR 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 the application for this
rule to USEPA, or the effective date of
its revised regulations, whichever is
later. In addition, a State that wishes to
obtain interim primacy for future
NPDWRs must obtain primacy for this
rule. As described in Section IV.A, EPA
expects to oversee the initial source
water monitoring that will be conducted
under the LT2ESWTR by systems
serving at least 10,000 people, beginning
6 months following rule promulgation.
VI. Economic Analysis
This section summarizes the
economic analysis (EA) for the
LT2ESWTR proposal. The EA is an
assessment of the benefits, both health
and non-health related, and costs to the
regulated community of the proposed
regulation, along with those of
regulatory alternatives that the Agency
considered. EPA developed this EA to
meet the requirement of SOW A section
1412(b)(3)(C) for a Health Risk
Reduction and Cost Analysis (HRRCA),
as well as the requirements of Executive
Order 12866, Regulatory Planning and
Review, under which EPA must
estimate the costs and benefits of the
LT2ESWTR. The full EA is presented in
Economic Analysis for the Long Term 2
Enhanced Surface Water Treatment Rule
(USEPA 2003a), which is available in
the docket for today's proposal
(www. epa .gov.edocketl).
Today's proposed LT2ESWTR is the
second in a staged set of rules that
address public health risks from
microbial contamination of surface and
GWUDI drinking water supplies and,
more specifically, prevent
Cryptosporidium from reaching
consumers. As described in section I,
the Agency promulgated the IESWTR
and LT1ESWTR to provide a baseline of
protection against Cryptosporidium in
large and small drinking water systems,
respectively. Today's proposed rule
would achieve further reductions in
Cryptosporidium exposure for systems
with the highest vulnerability. This
economic analysis considers only the
incremental reduction in exposure from
the two previously promulgated rules
(IESWTR and LTlESWTR) to the
alternatives evaluated for the
LT2ESWTR.
Both benefits and costs are
determined as annualized present
values. The process allows comparison
of cost and benefit streams that are
variable over a given time period. The
time frame used for both benefit and
cost comparisons is 25 years;
approximately five years account for
rule implementation and 20 years for
the average useful life of the equipment
used to comply with treatment
technique requirements. The Agency
uses social discount rates of both three
percent and seven percent to calculate
present values from the stream of
benefits and costs and also to annualize
the present value estimates (seeEPA's
Guidelines for Preparing Economic
Analyses (USEPA 2000c) for a
discussion of social discount rates). The
LT2ESWTR EA (USEPA 2003a) also
shows the undiscounted stream of both
benefits and costs over the 25 year time
frame.
A. What Regulatory Alternatives Did the
Agency Consider?
Regulatory alternatives considered by
Agency for the LT2ESWTR were
developed through the deliberations of
the Stage 2 M-DBP Federal Advisory
Committee (described in section II). The
Committee considered several general
approaches for reducing the risk from
Cryptosporidium in drinking water. As
discussed in section IV.A.2, these
approaches included both additional
treatment requirements for all systems
and risk-targeted treatment
requirements for systems with the
highest vulnerability to
Cryptosporidium following
implementation of the IESWTR and
LTlESWTR. In addition, the Committee
considered related factors such as
surrogates for Cryptosporidium
monitoring and alternative monitoring
strategies to minimize costs to small
drinking water systems.
After considering these general
approaches, the Committee focused on
four specific regulatory alternatives for
filtered systems (see Table VI-1). With
the exception of Alternative 1, which
requires all systems to achieve an
additional 2 log (99%) reduction in
Cryptosporidium levels, these
alternatives incorporate a microbial
framework approach. In this approach,
systems are classified in different risk
bins based on the results of source water
monitoring. Additional treatment
requirements are directly linked to the
risk bin classification. Accordingly,
these rule alternatives are differentiated
by two criteria: (1) The Cryptosporidium
concentrations that define the bin
boundaries and (2) the degree of
treatment required for each bin.
In assessing regulatory alternatives,
EPA and the Advisory Committee were
concerned with the following questions:
(1) Do the treatment requirements
adequately control Cryptosporidium
concentrations in finished water? (2)
How many systems will be required to
add treatment? (3) What is the
likelihood that systems with high source
water Cryptosporidium concentrations
will not be required to provide
additional treatment (i.e., be
misclassified in a low risk bin)? and (4)
What is the likelihood that systems with
low source water Cryptosporidium
concentrations will be required to
provide unnecessary additional
treatment (i.e., misclassified in a high
risk bin)?
The Committee reached consensus
regarding additional treatment
requirements for unfiltered systems and
uncovered finished water storage
facilities without formally identifying
regulatory alternatives. Table VI-1
summarizes the four alternatives that
were considered for filtered systems.
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47739
TABLE VI-1.—SUMMARY OF REGULATORY ALTERNATIVES FOR FILTERED SYSTEMS
Average source water Cryptosporidium monitoring result (oocysts/L)
Additional
treatment re-
quirements 1
Alternative A1
2.0 log inactivation required for all systems
Alternative A2
>1.0
No action.
0.5 log.
1.5 log.
2.5 log.
Alternative A3—Preferred Alternative
< 0.075
> 0.075 and < 1.0
> 1.0 and <3.0 ....
>3.0
No action.
1 log.
2 log.
2.5 log.
Alternative A4
>0.1 and< 1.0
No action.
0.5-log.
1.0 log.
Note: "Additional treatment requirements" are in addition to levels already required under existing rules (e.g., the IESWTR and LT1ESWTR).
B. What Analyses Support Selecting the
Proposed Rule Option?
EPA has quantified benefits and costs
of each of the regulatory alternatives in
Table VI-1, as well as for the proposed
requirements for unfiltered systems.
Quantified benefits stem from estimated
reductions in the incidence of
cryptosporidiosis resulting from the
regulation. To make these estimates, the
Agency developed a two-dimensional
Monte Carlo model that accounts for
uncertainty and variability in key
parameters like Cryptosporidium
occurrence, infectivity, and treatment
efficiency. Analyses involved estimating
the baseline (pre-LT2ESWTR) risk from
Cryptosporidium in drinking water, and
then projecting the reductions in
exposure and risk resulting from the
additional treatment requirements of the
LT2ESWTR. Costs result largely from
the installation of additional treatment,
with lesser costs due to monitoring and
other implementation activities. Results
of these analyses are summarized in the
following subsections, and details are
shown in trie LT2ESWTR EA (USEPA
2003a).
Cryptosporidium occurrence
significantly influences the estimated
benefits and costs of regulatory
alternatives. As discussed in section
III.C, EPA analyzed data collected under
the Information Collection Rule, the
Information Collection Rule
Supplemental Surveys of medium
systems (ICRSSM), and the Information
Collection Rule Supplemental Surveys
of large systems (ICRSSL) to estimate
the national occurrence distribution of
Cryptosporidium in surface water. EPA
evaluated these distributions
independently when assessing benefits
and costs for different regulatory
alternatives. In most cases, results from
the ICRSSM data set are within the
range of results of the Information
Collection Rule and ICRSSL data sets.
EPA selected a Preferred Regulatory
Alternative for the LT2ESWTR,
consistent with the recommendations of
the Advisory Committee. As described
next, this selection was based on the
estimated impacts and feasibility of the
alternatives shown in Table VI-1.
Alternative Al (across-the-board 2-log
inactivation) was not selected because it
was the highest cost option and
imposed costs but provided few benefits
to systems with high quality source
water (i.e., relatively low
Cryptosporidium risk). In addition,
there were concerns about the feasibility
of requiring almost every surface water
treatment plant to install additional
treatment processes (e.g., UV or ozone)
for Cryptosporidium.
Alternatives A2-A4 were evaluated
based on several factors, including
predictions of costs and benefits,
performance of analytical methods for
classifying systems in the risk bins, and
other specific impacts (e.g., impacts on
small systems or sensitive
subpopulations). Alternative A3 was
recommended by the Advisory
Committee because it provides
significant health benefits in terms of
avoided illnesses and deaths for an
acceptable cost. In addition, the Agency
believes this alternative is feasible with
available analytical methods and
treatment technologies.
Incremental costs and benefits of
regulatory alternatives for the
LT2ESWTR are shown in section VI.F,
and the LT2ESWTR EA contains more
detailed information about the benefits
and costs of each regulatory option
EUSEPA 2003a).
C. What Are the Benefits of the
Proposed LT2ESWTR?
As discussed previously, the
LT2ESWTR is expected to substantially
reduce drinking water related exposure
to Cryptosporidium, thereby reducing
both illness and death associated with
cryptosporidiosis. As described in
section II, cryptosporidiosis is an
infection caused by Cryptosporidium
and is an acute, typically self-limiting,
illness with symptoms that include
diarrhea, abdominal cramping, nausea,
vomiting, and fever (Juranek, 1995).
Cryptosporidiosis patients in sensitive
subpopulations, such as infants, the
elderly, and AIDS patients, are at risk
for severe illness, including risk of
death. While EPA has quantified and
monetized the health benefits for
reductions in endemic cryptosporidiosis
that would result from the LT2ESWTR,
the Agency was unable to quantify or
monetize other health and non-health
related benefits associated with this
rule. These unquantified benefits are
characterized next, followed by a
summary of the quantified benefits.
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Federal Register/Vol. 68, No. 154/Monday, August 11, 2003/Proposed Rules
1. Non-Quantifiable Health and Non-
health Related Benefits
Although there are substantial
monetized benefits that result from this
rule due to reduced rates of endemic
cryptosporidiosis, other potentially
significant benefits of this rule remain
unquantified and non-monetized. The
unquantified benefits that result from
this rule are summarized in Table VI-
2 and are described in greater detail in
the LT2ESWTR EA (USEPA 2003a).
TABLE VI-2.—SUMMARY OF NONQUALIFIED BENEFITS
Benefit type
Potential effect on benefits
Comments
Reducing outbreak risks and response costs
Increase
Reducing averting behavior (e.g., boiling tap water or
purchasing bottled water).
Improving aesthetic water quality
Reducing risk from co-occurring and emerging patho-
gens.
Increased source water monitoring
Increase / No Change
Increase
Increase
Reduced contamination due to covering on treating fin-
ished water storage facilities.
Increase
Increase
Some outbreaks are caused by human or equipment
failures that may occur even with the proposed new
requirements; however, by adding barriers of protec-
tion for some systems, the rule will reduce the possi-
bility of such failures leading to outbreaks.
Averting behavior is associated with both out-of-pocket
costs (e.g., purchase of bottled water) and oppor-
tunity costs (e.g., time requiring to boil water) to the
consumer. Reductions in averting behavior are ex-
pected to have a positive impact on benefits from the
rule.
Some technologies installed for this rule (e.g., ozone)
are likely to reduce taste quality and odor problems.
Although focused on removal of Cryptosporidium from
drinking water, systems that change treatment proc-
esses will also increase removal of pathogens that
the rule does not specifically regulate. Additional ben-
efits will accrue.
The greater understanding of source water quality that
results from monitoring may enhance the ability of
plants to optimize treatment operations in ways other
than those addressed in this rule.
Although insufficient data were available to quantify
benefits, the reduction of contaminants introduced
through uncovered finished water storage facilities
would produce positive public health benefits.
Source: Chapter 5 of the LT2ESWTR Economic Analysis (USEPA 2003a).
2. Quantifiable Health Benefits
EPA quantified benefits for the
LT2ESWTR based on reductions in the
risk of endemic cryptosporidiosis.
Several categories of monetized benefits
were considered in this analysis.
First, EPA estimated the number of
cases expected to result in premature
mortality (primarily for members of
sensitive subpopulations such as AIDS
patients). In order to estimate the
benefits from deaths avoided as a result
of the rule, EPA multiplied the
estimates for number of illnesses
avoided by a projected mortality rate.
This mortality rate was developed using
mortality data from the Milwaukee
cryptosporidiosis outbreak of 1993
(described in section II), with
adjustments to account for the
subsequent decrease in the mortality
rate among people with AIDS and for
the difference between the 1993
Milwaukee AIDS rate and the current
national rate. EPA estimated a mortality
rate of 16.6 deaths per 100,000 illnesses
for those served by unaltered systems
and a mortality rate of 10.6 deaths per
100,000 illnesses for those served by
filtered systems. These different rates
are associated with the incidence of
AIDS in populations served by
unfiltered and filtered systems. A
complete discussion on how EPA
derived these rates can be found in
subchapter 5.2 of the LT2ESWTR EA
(USEPA 2003a).
Reductions in mortalities were
monetized using EPA's standard
methodology for monetizing mortality
risk reduction. This methodology is
based on a distribution of value of
statistical life (VSL) estimates from 26
labor market and stated preference
studies, with a mean VSL of S6.3M in
2000, and a 5th to 95th percentile range
of $1.0 to $14.5. A more detailed
discussion of these studies and the VSL
estimate can be found in EPA's
Guidelines for Preparing Economic
Analyses (USEPA 2000c). A real income
growth factor was applied to these
estimates of approximately 2.3% per
year for the 20 year time span following
implementation. Income elasticity for
VSL was estimated as a triangular
distribution that ranged from 0.08 to
1.00, with a mode of 0.40. VSL values
for the 20 year span are shown in the
LT2 EA in Exhibit C.13 (USEPA 2003a).
The substantial majority of cases are
not expected to be fatal and the Agency
separately estimated the value of non-
fatal illnesses avoided that would result
from the LT2ESWTR. For these, EPA
first divided projected cases into three
categories, mild, moderate, and severe,
and then calculated a monetized value
per case avoided for each severity level.
These were then combined into a
weighted average value per case based
on the relative frequency of each
severity level. According to a study
conducted by Corso et al (2003), the
majority of illness falls into the mild
category (88 percent). Approximately 11
percent of illness falls into the moderate
category, which is defined as those who
seek medical treatment but are not
hospitalized. The final one percent have
severe symptoms that result in
hospitalization. EPA estimated different
medical expenses and time losses for
each category.
Benefits for non-fatal cases were
calculated using a cost-of-illness (COI)
approach. Traditional COI valuations
focus on medical costs and lost work
time, and leave out significant
categories of benefits, specifically the
reduced utility from being sick (i.e., lost
personal or non-work time, including
activities such as child care,
homemaking, community service, time
spent with family, and recreation),
although some COI studies also include
an estimate for unpaid labor (household
production) valued at an estimated wage
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47741
rate designed to reflect the market value
of such labor (e.g., median wage for
household domestic labor). This
reduced utility is variously referred to
as lost leisure or a component of pain
and suffering. Ideally, a comprehensive
willingness to pay (WTP) estimate
would be used that includes all
categories of loss in a single number.
However, a review of the literature
indicated that the available studies were
not suitable for valuing
cryptosporidiosis; hence, estimates from
this literature are inappropriate for use
in this analysis. Instead, EPA presents
two COI estimates: a traditional
approach that only includes valuation
for medical costs and lost work time
(including some portion of unpaid
household production); and an
enhanced approach that also factors in
valuations for lost unpaid work time for
employed people, reduced utility (or
sense of well-being) associated with
decreased enjoyment of time spent in
non-work activities, and lost
productivity at work on days when
workers are ill but go to work anyway.
Table Vl-3 shows the various
categories of loss and how they were
valued for each estimate for a "typical"
case (weighted average of severity
level—see LT2ESWTR EA—Chapter 5
for more details (USEPA 2003a).
TABLE Vl-3.—TRADITIONAL AND ENHANCED COI FOR CRYPTOSPORIDIOSIS
Loss category
Lost Paid Work Days
Lost Unpaid Work Days1 '.
Total4
Traditional
COI
$9382
10988
2022
20 70
5
5
24462
Enhanced COI
$93 82
109 88
4044
54 31
333 96
11249
744 89
1 Assigned to 38.2% of the population not engaged in market work; assumes 40 hr, unpaid work week, valued at $5.46/hr in traditional COI
and $10.92/hr in enhanced COI. Does not include lost unpaid work for employed people and may not include all unpaid work for people outside
the paid labor force.
2 Values lost work or leisure time for people caring for the ill. Traditional approach does not include lost leisure time.
3 Includes child care and homemaking (to the extent not covered in lost unpaid work days above), time with family, and recreation for people
within and outside the paid labor force.
4 Detail may not calculate to totals due to independent rounding; Source: Appendix L in LT2ESWTR EA (USEPA 2003a).
5 Not included.
The various loss categories were
calculated as follows: Medical costs are
a weighted average across the three
illness severity levels of actual costs for
doctor and emergency room visits,
medication, and hospital stays. Lost
paid work represents missed work time
of paid employees, valued at the median
pre-tax wage, plus benefits of $18.47
hour. The average number of lost work
hours per case is 5.95 (this assumes that
62 percent of the population is in the
paid labor force and the loss is averaged
over seven days). Medical costs and lost
work days reflect market transactions.
Medical costs are always included in
COI estimates and lost work days are
usually included in COI estimates.
In the traditional COI estimate, an
equivalent amount of lost unpaid work
time was assigned to the 38% of the
population that are not in the paid labor
force. This includes homemakers,
students, children, retires, and
unemployed persons. EPA did not
attempt to calculate what percent of
cases falls in each of these five groups,
or how many hours per week each
group works, but rather assumed an
across-the-board 40 hour unpaid work
week. This time is valued at $5.46 per
hour, which is one half the median post-
tax wage, (since work performed by
these groups is not taxed). This is
approximately the median wage for paid
household domestic labor.
In the enhanced COI estimate, all time
other than paid work and sleep (8 hours
per day) is valued at the median after
tax wage, or $10.92 per hour. This
includes lost unpaid work (e.g.,
household production) and leisure time
for people within and outside the paid
labor force. Implicit in this approach, is
that people would pay the same amount
not to be sick during their leisure time
as they require to give up their leisure
time to work (i.e., the after tax wage). In
reality, people might be willing to pay
either more than this amount (if they
were very sick and suffering a lot) or
less than this amount (if they were not
very sick and still got some enjoyment
out of activities such as resting, reading
and watching TV), not to be sick.
Multiplying 16 hours by $10.92 gives a
value of about $175.00 for a day of
"lost" unpaid work and leisure (i.e., lost
utility of being sick).
An estimate of lost unpaid work days
for the enhanced approach was made by
assigning the value of $10.92 per hour
to the same number of unpaid work
hours valued in the traditional COI
approach (i.e., 40 unpaid work hours
per week for people outside the paid
labor force). Lost unpaid work for
employed people and any unpaid labor
beyond 40 hours per week for those not
in the labor market is shown as lost
leisure time in Table VI-3 for the
enhanced approach and is not included
in the traditional approach. In addition,
for days when an individual is well
enough to work but still experiencing
symptoms, such as diarrhea, the
enhanced estimate also includes a 30%
loss of work and leisure productivity,
based on a study of giardiasis illness
(Harrington et al. 1985) which is similar
to cryptosporidiosis. Appendix P in the
EA describes similar productivity losses
for other illnesses such as influenza
(35%-73% productivity losses). In the
traditional COI analysis, productivity
losses are not included for either work
or non-work time.
The Agency believes that losses in
productivity and lost leisure time are
unquestionably present and that these
categories have positive value;
consequently, the traditional COI
estimate understates the true value of
these loss categories. EPA notes that
these estimates should not be regarded
as upper and lower bounds. In
particular, the enhanced COI estimate
may not fully incorporate the value of
pain and suffering, as people may be
willing to pay more than $201 to avoid
a day of illness. The traditional COI
estimate includes a valuation for a lost
40 hour work week for all persons not
in the labor force, including children
and retirees. This may be an
overstatement of lost productivity for
these groups, which would depend on
the impact of such things as missed
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school work or volunteer activities that
may be affected by illness.
As with the avoided mortality
valuation, the real wages used in the
COI estimates were increased by a real
income growth factor that varies by
year, but is the equivalent of about 2.3%
over the 20 year period. This approach
of adjusting for real income growth was
recommended by the SAB (USEPA
2000e) because the median real wage is
expected to grow each year (by
approximately 2.3%)—the median real
wage is projected to be $38,902 in 2008
and $59,749 in 2027. Correspondingly,
the real income growth factor of the COI
estimates increases by the equivalent of
2.3% per year (except for medical costs,
which are not directly tied to wages).
This approacb gives a total COI
valuation in 2008 of $268.92 for the
traditional COI estimate and $931.06 for
the enhanced COI estimate; the
valuation in 2027 is $362.75 for the
traditional COI estimate and $1,429.99
for the enhanced COI estimate. There is
no difference in the methodology for
calculating the COI over this 20 year
period of implementation; the change in
valuation is due to the underlying
change in projected real wages.
Table VI-4 summarizes the annual
cases of cryptosporidiosis illness and
associated deaths avoided due to the
LT2ESWTR proposal. The proposed
rule, on average, is expected to reduce
256,000 to 1,019,000 illnesses and 37 to
141 deaths annually after full
implementation (range based on the
ICRSSL, ICRSSM, and Information
Collection Rule data sets).
TABLE VI-4,—SUMMARY OF ANNUAL AVOIDED ILLNESS AND DEATHS
Data set
Annual illinesses avoided
Mean
90 percent confidence
bound
Lower
(5th %ile)
Upper
(95th %ile)
Annual deaths avoided
Mean
90 percent confidence
bound
Lower
(5th %ile)
Upper
(95th %He)
Annual Total After Full Implementation
ICR
ICRSSM
1,018,915
256,173
498,363
169,358
45,292
84,724
2,331 ,467
560,648
1,177,415
141
37
70
25
7
13
308
78
157
Annual Average Over 25 years
ICRSSM
720,668
181,387
352,611
119,694
32,179
59,942
1,647,796
396,845
833,290
100
26
50
18
5
9
218
55
111
Source: The LT2ESWTR Economic Analysis (USEPA 2003a).
Tables VI-5a and VI-5b show the
monetized present value of the benefit
for reductions in endemic
cryptosporidiosis estimated to result
from the LT2ESWTR for the enhanced
and traditional COI values, respectively.
Estimates are given for the Information
Collection Rule, ICRSSL, and ICRSSM
occurrence data sets.
With the enhanced COI and a three
percent discount rate, the annual
present value of the mean benefit
estimate ranges from $374 million to
$1.4 billion, with a 90 percent
confidence bound of $52 million to
$198 million at the lower 5th percentile
and $959 million to $3.7 billion at the
upper 95th percentile; at a seven
percent discount rate, this estimate
ranges from $318 million to $1.2 billion,
with a 90 percent confidence bound of
$44 million to $168 million at the lower
5th percentile and $816 million to $3.1
billion at the upper 95th percentile.
With the traditional COI, the
corresponding benefit estimate at a three
percent discount rate ranges from $253
million to $967 million, with a 90
percent confidence bound of $27
million to $105 million at the lower 5th
percentile and $713 million to $2.7
billion at the upper 95th percentile; for
a seven percent discount rate, this
estimate ranges from $216 million to
$826 million, with a 90 percent
confidence bound of $23 million to $89
million at the lower 5th percentile and
$610 million to $2.3 billion at the upper
95th percentile. None of these values
include the unquantified and non-
monetized benefits discussed
previously:
TABLE VI-5A.—:
SUMMARY OF QUANTIFIED BENEFITS—ENHANCED COI
[Smillions, 2000$]
Data set
Value of benefits— Enhanced COI 1
Mean
90 percent confidence bound
Lower
(5th %ile)
Upper
{95th %ile)
Annuallzed Value (at 3%, 25 Years)
ICRSSM
$1,445
374
715
$198
52
96
3,666
959
1,849
Annualized Value (at 7%, 25 Years)
ICR
1,230
168
3,120
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47743
TABLE VI-5A.—SUMMARY OF QUANTIFIED BENEFITS—ENHANCED COI—Continued
[Smillions, 2000$]
Data set
1CRSSM
Value of benefits— Enhanced COI 1
Mean
318
609
90 percent confidence bound
Lower
(5th %ile)
44
81
Upper
(95th %ile)
816
1,577
The traditional COt only includes valuation for medical costs and lost work time (including some portion of unpaid household production). The
enhanced COI also factors in valuations for lost personal time (non-worktime) such as child care and homemakmg (to the extent not covered by
the traditional COI), time with family, and recreation, and lost productivity at work on days when workers are ill but go to work anyway. Source:
The LT2ESWR Economic Analysis (USEPA 2003a).
TABLE VI-5B.—SUMMARY OF QUANTIFIED BENEFITS—TRADITIONAL COI
[(SMillions, 2000$]
Data Set
Value of Benefits — Traditional
con
Mean
90 percent con-
fidence bound
Lower
(5th %ile)
Upper
95th %ile)
Annualized Value (at 3%, 25 Years)
ICRSSM
$967
253
481
$105
27
50
$2,713
713
1,372
Annualized Value (at 7%, 25 Years)
ICRSSM
826
216
411
89
23
43
2,315
610
1,172
1 The traditional COI only includes valuation for medical costs and lost work time (including some portion of unpaid household production). The
enhanced COI also factors in valuations for lost personal time (non-worktime) such as child care and homemaking (to the extent not covered by
the traditional COI), time with family, and recreation, and lost productivity at work on days when workers are ill but go to work anyway. Source:
The LT2ESWTR Economic Analysis (USEPA 2003a).
a. Filtered systems. Benefits to the
approximately 161 million people
served by filtered surface water and
GWUDI systems range from 88,000 to
472,000 reduction in mean annual cases
of endemic illness based on ICRSSL,
ICRSSM, and ICR data sets. In addition,
premature mortality is expected to be
reduced by an average of 9 to 50 deaths
annually.
b. Unfihered systems. The 12 million
people served by unfiltered surface
water or GWUDI systems will see a
significant reduction in
cryptosporidiosis as a result of the
LT2ESWTR. In this population, the rule
is expected to reduce approximately
168,000 to 547,000 cases of illness and
28 to 91 premature deaths annually.
For unfiltered systems, only the
Information Collection Rule data set is
used to directly calculate illness
reduction because it is the only data set
that includes sufficient information on
unfiltered systems. Illness reduction in
unfiltered systems was estimated for the
ICRSSL and ICRSSM data sets by
multiplying the Information Collection
Rule unfiltered system result by the
ratio, for the quantity estimated,
between filtered system results from the
supplemental survey data set (SSM or
SSL) and filtered system results from
the Information Collection Rule.
3. Timing of Benefits Accrual (Latency)
In previous rulemakings, some
commenters have argued that the
Agency should consider an assumed
time lag or latency period in its benefits
calculations. The Agency has not
conducted a latency analysis for this
rule because cryptosporidiosis is an
acute illness; therefore, very little time
elapses between exposure, illness, and
mortality. However, EPA does account
for benefits and costs that occur in
future years by converting these to
present value estimates.
D. What Are the Costs of the Proposed
LT2ESWTR?
In order to estimate the costs of
today's proposed rule, the Agency
considered impacts on public water
systems and on States (including
territories and EPA implementation in
non-primacy States). EPA assumed that
systems would be in compliance with
the IESWTR, which has a compliance
date of January 2002 for large systems
and the LTlESWTR, which has a
compliance date of January 2005 for
small systems. Therefore, this cost
estimate only considers the additional
requirements that are a direct result of
the LT2ESWTR. More detailed
information on cost estimates are
described next and a complete
discussion can be found in chapter 6 of
the LT2ESWTR EA (USEPA 2003a). An
detailed discussion of the proposed rule
provisions is located in section IV of
this preamble.
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1. Total Annualized Present Value Costs
Tables VI-6a and VI-6b summarize
the annualized present value cost
estimates for the proposed LT2ESWTR
at three percent and seven percent
discount rates, respectively. The mean
annualized present value costs of the
proposed LT2ESWTR are estimated to
range from approximately $73 to $111
million using a three percent discount
rate and $81 to $121 million using a
seven percent discount rate. This range
in mean cost estimates is associated
with the ICRSSL and Information
Collection Rule Cryptosporidium
occurrence data sets. Using different
occurrence data sets results in different
bin classifications and, thus, impacts
the cost of the rule. Results for the
ICRSSM fall within the range of results
for the Information Collection Rule and
ICRSSL. In addition to mean estimates
of costs, the Agency calculated 90
percent confidence bounds by
considering the uncertainty in
Cryptosporidium occurrence estimates
and around the mean unit technology
costs (USEPA 2003a).
Public water systems will incur
approximately 99 percent of the rule's
total annualized present value costs.
States incur the remaining rule costs.
Table VI-7 shows the undiscounted
initial capital and one-time costs broken
out by rule component. A comparison of
annualized present value costs among
the rule alternatives considered by the
Agency is located in subsection VI.F.
and in the LT2ESWTR EA (USEPA
2003a). Using a present value allows
costs and benefits that occur during
different time periods to be compared.
For any future cost, the higher the
discount rate, the lower the present
value. Specifically, a future cost
evaluated at a seven percent discount
rate will always result in a lower total
present value cost than the same future
cost evaluated at a three percent
discount rate,
BILLING CODE 6560-50-P
-------
Federal Register/Vol. 68, No. 154/Monday, August 11, 2003/Froposed Rules
47745
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47746
Federal Register/Vol. 68, No. 154/Monday, August 11, 2003/Proposed Rules
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Federal Register/Vol. 68, No. 154/Monday, August 11, 2003/Proposed Rules
47747
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-------
47748
Federal Register/Vol. 68, No. 154/Monday, August 11, 2003/Proposed Rules
BILLING CODE 6560-50-C
2. Water System Costs
The proposed LT2ESWTR applies to
all community, non-transient non-
community, and transient non-
community water systems that use
surface water or GWUDI as a source
(including both filtered and unfiltered
systems). EPA has estimated the cost
impacts for these three types of public
drinking water systems. As shown in
Table VI-6a and VI-6b, the mean
annualized present value costs for all
drinking water systems range from
approximately $73 to $111 million
using a three percent discount rate ($81
to $121 million using a seven percent
discount rates).
The majority of costs of the rule result
from treatment changes incurred by
filtered and unfiltered systems. Table
Vl-8 shows the number of filtered and
unfiltered systems that will incur costs
by rule provision. Subsection VI.D.2.b
discusses treatment costs for filtered
system and subsection VI.D.2.C
discusses treatment options for
unfiltered systems. All non-purchased
surface water and GWUDI systems
subject to the LT2ESWTR (including
filtered and unfiltered systems) will
incur one-time costs that include time
for staff training on rule requirements.
Systems will incur monitoring costs to
assess source water Cryptosporidium
levels, though monitoring requirements
vary by system size (large vs. small) and
system type (filtered vs. unfiltered). A
discussion of future monitoring that will
occur six years after initial bin
assignments can be found in subsection
VI.D.2.e.
BILLING CODE 6560-SO-P
Tgble Vl-8.- Number of Filtered and Unfiltered Systems and Plants Expected to
Incur Costs1
Dataset
ICR
ICRSSL
ICRSSM
Nonpurchased Systems and Plants
System Size
(population
served)
< 10,000
> 10,000
Total
< 10.000
> 10.000
Total
< 10,000
> 10,000
Total
Systems
Incurring
Implementation
Costs
A
5,662
1,384
7,066
Source Water Monitoring - Plants
Initial E.
Coll
Monitoring
B
5,792
1,774
7,565
Same as ICR
Same as ICR
Initial
Crypto
Monitoring
C
2,016
1,774
3,789
1,295
1,774
3,069
1,575
1,774
3,349
Future
E coli
Monitoring
D
5,122
1,273
6,395
5,409
1,453
6,862
5,347
1,386
6,733
Future
Crypto
Monitoring
E
1,782
1,273
3,056
1,209
1,453
2,662
1,454
1,386
2,840
Plants
Adding
Treatment
F
2.251
733
2,984
1,463
481
1,944
1,768
578
2,346
Systems
with
Uncovered
Reservoirs
G
32
106
138
Same as ICR
Same as ICR
'Numbers shown for plants monitoring include nonpurchased plants only. Numbers shown for plants adding
treatment include both nonpurchased plants and a fraction of plants purchasing water that could not be linked to a
nonpurchased plant. Source: Chapter 6 of the LT2ESWTR Economic Analysis (USEPA 2003a)
BILLING CODE 6560-50-C
a. Source water monitoring costs.
Source water monitoring costs are
structured on a per-plant basis. Also, as
with implementation activities,
purchased plants are assumed not to
treat source water and will not have any
monitoring costs. There are three types
of monitoring that plants may be
required to conduct—turbidity, E. coli
and Cryptosporidium. Source water
turbidity is a common water quality
parameter used for plant operational
control. Also, to meet SWTR,
LT1ESWTR and IESWTR requirements,
most water systems have turbidity
analytical equipment in-house and
operators are experienced with turbidity
measurement. Thus, EPA assumes that
the incremental turbidity monitoring
burden associated with the LT2ESWTR
is negligible.
Filtered plants in small systems
initially will be required to conduct one
year of biweekly E. coli source water
monitoring. These plants will be
required to monitor for Cryptosporidium
if, as a result of initial bin classification,
E. coli levels exceed the following
concentrations: (1) Annual mean > 10 E.
co/i/100 mL for lakes and reservoir
sources, and (2) annual mean > 50 E.
co/j/100 mL for flowing stream sources.
EPA estimated the percent of small
plants that would be triggered into
Cryptosporidium monitoring as being
equal to the percent of large plants that
would fall into any bin requiring
additional treatment.
Estimates of laboratory fees, shipping
costs, labor hours for sample collection,
and hours for reporting results were
used to predict system costs for initial
source water monitoring under the
LT2ESWTR. Table VI-9 summarizes the
present value of monitoring costs for
initial bin classification. Total present
value monitoring costs for initial bin
classification range from $46 million to
$60 million depending on the
occurrence data set and discount rate.
Appendix D of the LT2ESWTR EA
provides a full explanation of how these
costs were developed (USEPA 2003a).
-------
Federal Register/Vol. 68, No. 154/Monday, August 11, 2003/Proposed Rules
47749
TABLE VI-9.— SUMMARY OF PRESENT VALUE MONITORING COSTS FOR INITIAL BIN CLASSIFICATION
(Smillions, 2000$)
System Size
<10K
10K
Total
ICR (3%)
A
$34.6
25.7
60.3
ICR (7%)
B
$29.7
24.3
54.0
ICRSSL (3%)
C
$25.7
25.7
51.4
ICRSSL (7%)
D
$22.2
24.3
46.5
ICRSSM (3%)
E
$29.2
25.7
54.9
ICRSSM (7%)
F
$25.1
24.3
49.4
Source: Chapter 6 of the LT2ESWTR Economic Analysis (USEPA 2003a).
b. Filtered systems treatment costs.
The Agency calculated treatment costs
by estimating the number of plants that
will be adding treatment technologies
and coupling these estimates with unit
costs (S/plant) of the selected
technologies. Table VI-10 shows the
number of plants estimated to select
different treatment technologies; Table
VI-11 summarizes the present value
treatment costs and annualized present
value costs for both filtered and
unfiltered systems.
To estimate the number of filtered
plants that would select a particular
treatment technology, the Agency
followed a two step process. First, the
number of plants that must make
treatment changes to meet the proposed
LT2ESWTR requirement was
determined by the binning process.
Second, EPA predicted the treatment
technologies that plants would choose
to meet the proposed requirements. The
Agency used a "least-cost decision tree"
as the basic framework for determining
the treatment technology selection. In
other words, EPA assumed that drinking
water plants would select the least
expensive technology or combination of
technologies to meet the log removal
requirements of a given action bin.
However, these technology selections
were constrained by maximum use
percentages, which recognize that some
plants will not be able to implement
certain technologies because of site-
specific conditions. In addition, certain
potentially lower cost components of
the microbial toolbox, such as changes
to the plant intake, were not included
because the Agency Jacked data to
estimate the number of plants that could
select it. These limitations on
technology use may result in an
overestimate of costs. An in-depth
discussion of the technology selection
methodology and unit cost estimates
can be found in appendices E and F of
the proposed LT2ESWTR EA (USEPA
2003a).
TABLE VI-10.—TECHNOLOGY SELECTION FORECASTS FOR FILTERED PLANTS
Technology Selections
Technology Selections 1
Total Plants Selecting Technologies
Data set
ICR
1,545
190
77
16
5
10
26
24
9
0
998
0
2,893
ICRSSL
1,236
17
60
12
3
3
17
18
1
0
490
0
1,852
ICRSSM
1,441
52
70
14
4
5
21
21
2
0
632
0
2,255
Some plants are projected to select more than one technology to meet LT2ESWTR bin requirements; consequently the value for total plants
does not equal the sum of all technologies selected. Source: Chapter 6 of the LT2ESWTR Economic Analysis {USEPA 2003a).
c. Unfiltered systems treatment costs.
The proposed LT2ESWTR requires all
unfiltered plants to achieve 2 logs of
inactivation if their mean source water
Cryptosporidium concentration is less
than or equal to 0.01 oocysts/L and 3
logs of inactivation if it is greater than
0.01 oocysts/L. For most systems, UV
appears to be the least expensive
technology that can achieve the required
log inactivation of Cryptosporidium,
and it is expected to be widely used by
unfiltered systems to meet the rule
requirement. However, as with filtered
systems, EPA estimated that a small
percentage of plants would elect to
install a technology more expensive
than UV due to the configuration of
existing equipment or other factors.
Ozone is the next least expensive
technology that will meet the
inactivation requirements for some
systems, and is estimated to be used by
plants that do not use UV.
All unfiltered plants must meet
requirements of the LT2ESWTR;
therefore, the percent of plants adding
technology is 100 percent. This also
assumes that no unfiltered systems
currently use these additional treatment
technologies. For this cost analysis, the
Agency assumed 100 percent of very
small unfiltered systems will use UV;
for all other unfiltered system sizes, the
Agency estimated that 90 percent would
install UV and 10 percent would add
ozone. This analysis is discussed in
more detail in the LT2ESWTR EA
(USEPA 2003a). Treatment costs for
unfiltered systems are included in Table
VI-11.
-------
47750
Federal Register/Vol. 68, No. 154/Monday, August 11, 2003/Proposed Rules
TABLE VI-11 .—TOTAL PRESENT VALUE AND ANNUALIZED PRESENT VALUE TREATMENT COSTS FOR FILTERED AND
UNFILTERED PLANTS
Data Set
ICR
TOTAL
ICRSSL
TOTAL
ICRSSM
TOTAL
1
System Size
(population
served)
<10,000
> 10,000
<10,000
>1 0,000
<10,000
>10,000
I ,
Present
Value Cap-
ital Costs at
3%
A
$76.1
1,092.4
1,168.5
42.8
707.1
749.8
52.6
842.4
894.9
I I
Present
Value Cap-
ital Costs at
7%
B
$56.0
868.0
924.0
31.5
561.8
593.3
38.7
669.3
. 708.0
Annualized
O&M Costs
at 3%
C
$5.2
26.1
31.3
2.9
16.2
19.0
3.5
19.4
23.0
Annualized
O&M Costs
at 7%
D
$4.3
22.7
26.9
2.4
14.0
16.4
2.9
16.9
19.8
Total
Annuallized
Costs at 3%
E
$9.6
88.8
98.4
5.3
56.8
62.1
6.6
67.8
74.4
Total
Annualized
Costs at 7%
F
$9.1
97.1
106.2
5.1
62.3
67.3
6.2
74.3
80.6
Source: Chapter 6 of the LT2ESWTR Economic Analysis (USEPA 2003a)
d. Uncovered finished water storage
facilities. As part of the LT2ESWTR,
systems with uncovered finished water
storage facilities have the option to
cover the storage facility or provide
disinfection after the storage facility,
unless the State has determined that
existing risk mitigation is adequate.
Disinfection alternatives must achieve at
least four logs of virus inactivation. To
develop national cost estimates for
systems to comply with this provision
of the LT2ESWTR, unit costs for each
treatment alternative and the percentage
of systems selecting each alternative
were estimated for the inventory of
systems with uncovered finished water
storage facilities. A full description of
the unit costs and other assumptions
used in this analysis is presented in
Chapter 6 and Appendix I of the
LT2ESWTR EA (USEPA 2003a).
The Agency assumed that all systems
with uncovered finished water storage
facilities will have to either install a
cover or treat their discharge. This
overestimates the cost of this provision
because States can determine that
systems with uncovered finished storage
facilities do not need to take these
additional measures. The technology
selection for the uncovered finished
water storage facilities was developed
through a least-cost approach.
For systems with uncovered storage
facility capacities of five million gallons
(MG) or less, covering the storage
facilities is the least expensive
alternative. Although chlorination is the
least expensive alternative for the
remaining systems, the ability of a
system to use booster chlorination
depends on their current residual
disinfectant type. Less than half of all
surface water systems are predicted to
use chloramination following
implementation of the Stage 2 DBPR.
Adding chlorine to water that has been
treated with chloramines is not a
feasible alternative; therefore, the
fraction of systems projected to add
booster chlorination to the effluent from
the storage facility was estimated at 50
percent, with the remaining 50 percent
estimated to add covers. The technology
selection for uncovered finished water
storage facilities is presented in Table
VI-12.
TABLE VM 2.—ESTIMATED TECHNOLOGY SELECTION FOR UNCOVERED STORAGE FACILITIES
Size category (MG)
>1 5
>5-10
>10-20
>20-40
>40-60
>60-80 •
>80-100
>100-150
>150-200 •
>2QO-250
>250-1 000 •
>1.000
Number of uncovered
storage facilities
25
7
44
12
10
9
4
4
6
6
2
4
4
1
Floating
cover
(%)
100
100
100
100
100
50
50
50
50
50
50
50
50
50
Booster
chlorination
(%)
50
50
50
50
50
50
50
50
50
Source: Appendix I of the LT2ESWTR Economic Analysis (USEPA 2003a)
Table VI-13 summarizes total
annualized present value costs for the
uncovered storage facility provision
using both three and seven percent
discount rates. The Agency estimates
the total annualized present value cost
for covering or treating uncovered
finished water storage facilities to be
approximately $5.4 million at a three
percent discount rate and $6.4 million
at a seven percent discount rate.
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47751
TABLE VI-13— ESTIMATED ANNUALIZED PRESENT VALUE COST FOR UNCOVERED FINISHED WATER STORAGE FACILITY
PROVISION (2000$)
System size (population served)
>10,000
Total
Annualized cost at 3%
Capital
$3,520
3,349,320
3,352,840
O&M
$1,649
2,046,425
2,048,074
Total
$5,169
5,395,745
5,400,915
Annualized cost at 7%
Capital
$4,713
4,483,927
4,488,639
O&M
$1,552
1,925,203
1,926,754
Total
$6,264
6,409,129
6,415,393
Source: Appendix I of the LT2ESWTR Economic Analysis (USEPA 2003a)
e. Future monitoring costs. Six years
after initial bin classification, filtered
and unfiltered plants will be required to
conduct a second round of monitoring
to assess whether source water
Cryptosporidium levels have changed
significantly. EPA will evaluate new
analytical methods and surrogate
indicators of microbial water quality in
the interim. While the costs of
monitoring are likely to change in the
six years following rule promulgation, it
is difficult to predict how they will
change. In the absence of any other
information, it was assumed that the
laboratory costs would be the same as
for the initial monitoring.
All plants that conducted initial
monitoring were assumed to conduct
the second round of monitoring as well,
except for those systems that installed
treatment that reduces 2.5 logs of
Cryptosporidium or greater as a result of
the rule. These systems are exempt from
monitoring under the LT2ESWTR. Table
VI-8 shows the number of systems that
are estimated to conduct the second
round of monitoring (listed as "future"
monitoring in the table). EPA estimates
the cost of re-binning will range from
$23 million to $38 million depending
on the occurrence data set and discount
rate used in the estimate (see Table VI-
14). Costs differ among Cryptosporidium
occurrence data sets due to differences
in estimates of the number of plants that
will add technologies to achieve at least
2.5 log Cryptosporidium reduction and
the number of small plants that will be
triggered into monitoring for
Cryptosporidium. Appendix D of the EA
provides further details (USEPA 2003a).
TABLE vi-14.—PRESENT VALUE OF MONITORING COSTS OF FUTURE RE-BINNING
[Smillions, 2000$]
Total
ICR
(3%)
A
$23.5
14.4
37.8
ICR
(7%)
B
$14.3
9.8
24.1
ICRSSL
(3%)
C
$18.4
16.4
34.8
ICRSSL
(7%)
D
$11.3
11.2
22.5
ICRSSM
(3%)
E
$20.7
15.6
36.3
ICRSSM
(7%)
F
$12.6
10.7
23.3
Source: Chapter 6 of the LT2ESWTR Economic Analysis (USEPA 2003a
f. Sensitivity analysis—influent
bromide levels on technology selection
for filtered plants. One concern about
the ICR data set was that it may not
actually reflect influent bromide levels
in some plants during droughts. High
influent bromide levels (the precursor
forbromate formation) limits ozone use
because the plant would not be able to
meet the MCL for bromate. The Agency
conducted a sensitivity analysis to
estimate an impact of higher influent
bromide levels would have on
technology decisions. The sensitivity
analysis assumes influent bromide
concentrations of 50 parts per billion
(ppb) above the ICR concentrations.
Overall, the impact of these
assumptions have a minimal impact on
costs. A complete discussion of this
sensitivity analysis is located in
LT2ESWTR EA (USEPA 2003a).
3. State/Primacy Agency Costs
The Agency estimates that States and
primacy agencies will incur an
annualized present value cost of $0.9 to
$1.0 million using a three percent
discount rate and $1.2 million at seven
percent. State implementation activities
include regulation adoption and
program implementation, training State
staff, training PWS staff, providing
technical assistance to PWSs, and
updating the management system. To
estimate implementation costs to States/
Primacy Agencies, the number of full-
time employees (FTEs) per activity is
multiplied by the number of labor hours
per FTE, the cost per labor hour, and the
number of States and Territories.
In addition to implementation costs,
States and primacy agencies will also
incur costs associated with monitoring
data management. Because EPA will
directly manage the first round of
monitoring by large systems (serving at
least 10,000 people), States are not
predicted to incur costs for these
activities. States will, however, incur
costs associated with small system
monitoring. This is a result of the
delayed start of small system
monitoring, which will mean that some
States will assume primacy for small
system monitoring. In addition, States
will review of the second round of
monitoring results. States will also incur
costs in reviewing technology
compliance data and consulting with
systems regarding benchmarking for
systems that change their disinfection
procedures to comply with the rule.
Appendix D of the LT2ESWTR EA
provides more information about the
State and primacy agency cost analysis
(USEPA 2003a).
4. Non-Quantified Costs
EPA has quantified all the major costs
for this rule and has provided
uncertainty analyses to bound the over
or underestimates in the costs. There are
some costs that EPA has not quantified,
however, because of lack of data. For
example, some systems may merge with
neighboring systems to comply with this
rule. Such changes have both costs
(legal fees and connecting
infrastructure) and benefits (economies
of scale). Likewise, systems would incur
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costs for procuring a new source of
water that may result in lower overall
treatment costs.
In addition, the Agency was unable to
predict the usage or estimate the costs
of several toolbox options. These
options include intake management and
demonstrations of performance. They
have not been included in the
quantified analysis because data are not
available to estimate the number of
systems that may use these toolbox
options to comply with the LT2ESWTR.
Not including these generally low-cost
options may result in overestimation of
costs.
E. What Are the Household Costs of the
Proposed Rule?
Another way to assess a rule's impact
is to consider how it might impact
residential water bills. This analysis
considers the potential increase in a
household's water bill if a CWS passed
the entire cost increase resulting from
this rule on to its customers. It is a tool
to gauge potential impacts and should
not be construed as precise estimates of
potential changes to individual water
bills.
Included in this analysis are all CWS
costs, including rule implementation,
initial and future monitoring for bin
classification, additional
Cryptosporidium treatment, and treating
or covering uncovered finished water
storage facilities. Costs for small systems
Cryptosporidium monitoring, additional
Cryptosporidium treatment, and
uncovered finished water storage
facilities are assigned only to the subset
of systems expected to incur them.
Although implementation and
monitoring represent relatively small,
one-time costs, they have been included
in the analysis to provide a complete
distribution of the potential household
cost. A detailed description of the
derivation of household costs is in
section 6.10 and Appendix J of the
LT2ESTWR EA (USEPA 2003a).
For purchased systems that are linked
to larger nonpurchased systems, the
households costs are calculated based
on the unit costs of the larger system but
included in the distribution from the
size category of the purchased system.
Households costs for these purchased
systems are based on the household
usage rates appropriate for the retail
system and not the system selling the
water. This approach for the purchased
systems reflects the fact that although
they will not face increased costs from
adding their own treatment, whatever
costs the wholesale utility incurs would
likely be passed on as higher water
costs.
Table VI-15 shows the results of the
household cost analysis. In addition to
mean and median estimates, the Agency
calculated the 90th and 95th percentile.
EPA estimates that all households
served by surface and GWUDI sources
will face some increase in household
costs due to implementation of the
LT2ESWTR (except for those few served
by systems that have already installed
5.5 logs of treatment for
Cryptosporidium). Of all the households
subject to the rule, from 24 to 35 percent
are projected to incur costs for adding
treatment, depending on the
Cryptosporidium occurrence data set
used.
Approximately 95 percent of the
households potentially subject to the
rule are served by systems serving at
least 10,000 people; these systems
experience the lowest increases in costs
due to significant economies of scale.
Over 90 percent of all households will
face an annual cost increase of less than
$5. Households served by small systems
that install advanced technologies will
face the greatest increases in annual
costs. EPA expects that the model's
projections for these systems are, in
some cases, overstated. Some systems
are likely to find alternative treatment
techniques such as other toolbox
options not included in this analysis, or
sources of water (ground water,
purchased water, or consolidating with
another system) that would be less
costly than installing more expensive
treatment techniques.
TABLE VM 5.—POTENTIAL ANNUAL HOUSEHOLD COSTS IMPACTS FOR THE PREFERRED REGULATORY OPTION (2000$)
System; type/size
Households
Mean
Median
90th
Percentile
95th
Percentile
Percent of
systems with
household
cost increase
<$12
Percent of
systems with
household
cost increase
<$120
All Systems—ICR
All CWS
CWS < 10,000
65,816,979
3,318,012
$1.68
4.61
$0.13
1.34
$4.06
13.04
$7.57
14.92
98.37
87.88
99.99
99.88
All Systems—ICRSSL
All CWS
CWS < 10,000
65,816,979
3,318,012
$1.07
2.68
$0.03
0.80
$3.24
6.10
$5.43
9.39
98.31
95.71
100.00
99.95
AH Systems—1C RSSM
AH CWS
CWS< 10,000
65,816,979
3,318,012
$1.28
3.27
$0.03
0.80
$3.48
6.62
$6.47
13.04
99.07
93.90
100.00
99.93
Source: Chapter 6 of the LT2ESWTR Economic Analysis (USEPA 2003a).
F. What Are the Incremental Costs and
Benefits of the Proposed LT2ESWTR?
Incremental costs and benefits are
those that are incurred or realized in
reducing Cryptosporidium exposures
from one alternative to the next.
Estimates of incremental costs and
benefits are useful in considering the
economic efficiency of different
regulatory options considered by the
Agency. Generally, the goal of an
incremental analysis is to identify the
regulatory option where incremental
benefits most closely equal incremental
costs. However, the usefulness of this
analysis is limited because many
benefits from this rule are unquantified
and not monetized. Incremental
analyses should consider both
quantified and non-quantified (where
possible) benefits and costs.
Usually an incremental analysis
implies increasing levels of stringency
along a single parameter, with each
alternative providing all the protection
of the previous alternative, plus
additional protection. However, the
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47753
regulatory alternatives in this rule vary
by multiple parameters (e.g, risk bin
boundaries, treatment requirements).
The comparison between any two
alternatives is, therefore, between two
separate sets of benefits, in the sense
that they may be distributed to
somewhat different population groups.
The regulatory alternatives, however,
do achieve increasing levels of benefits
at increasing levels of costs. As a result,
it is possible to display incremental net
benefits from the baseline and
alternative to alternative. Tables VI—16a
and VI-16b show incremental costs,
benefits, and net benefits for the four
regulatory alternatives shown in Table
VI-1, using the enhanced and
traditional COI, respectively. All values
are annualized present values expressed
in Year 2000 dollars. The displayed
values are the mean estimates for the
different occurrence distributions.
With the enhanced COI, incremental
costs are generally closest to
incremental benefits for A2, a more
stringent alternative than the Preferred
Alternative, A3. For the traditional COI,
incremental costs most closely equal
incremental benefits for A3, the
Preferred Alternative, under the
majority of conditions evaluated.
BILLING CODE 6560-50-P
Table Vl-16a.- Incremental Net Benefits by Rule Alternative—Enhanced COI
(Annualized Present Value, $millions, 2000$)
Data
Set
Rule
Alternative
Annual
Costs
A
Annual
Benefits
B
Incremental
Costs[1]
C
Incremental
Benefits
D
Incremental Net
Benefits
E=D-C
3 Percent Discount Rate
ICR
A4
A3 - Preferred
A2
A1
$ 55
$ 111
$ 134
$ 361
$ 1,349
$ 1,445
$ 1,461
$ 1,482
$ 58
$ 52
$ 23
$ 227
* 1,349
$ 96
$ 16
$ 21
* i,yyu
$ 44
id -8
1 -206
ICRSSL
A4
A3 - Preferred
A2
A1
$ 37
$ 73
$ 100
$ 361
* 328
$ 374
$ 397
$ 457
$ . 37
$ 37
$ ' 26
$ 261
$ ^32B
$ 46
$ 24
$ 59
* 291
•p '
S -2
$ -202
ICRSSM
A4
A3 - Preferred
A2
A1
$ 44
$ 86
$ 113
$ 361
$ 635
$ 715
$ 742
$ 796
$ 44
$ 42
$ • 26
$ 246
$ 635
$ 80
$ 27
$ 53
$ 592
$ 38
$ 1
1 -195
7 Percent Discount Rate
ICR
A4
A3 - Preferred
A2
A1
$ bt>
$ 121
$ 145
$ 388
$ 1,148
$ 1 ,230
$ 1 ,243
$ 1 ,260
$ bb
$ 56
$ 25
$ 242
» 1,148
$ 82
$ 13
$ 18
» 1 ,UB3
5 26
* -11
* -225
ICRSSL
A4
A3 - Preferred
A2
A1
$ 41
$ 81
$ 108
$ 388
$ 279
$ 318
$ 338
$ 389
$ 41
$ 40
$ 27
$ 279
$ 279
$ 39
$ 20
$ 50
* 238
* -1
* -7
$ -229
ICRSSM
A4
A3 - Preferred
A2
A1
$^ 48
$ 94
$ 122
$ 388
$ 541
$ 609
$ 632
$ 677
$ 48
$ 47
$ 28
$ 265
$ 541
$ 68
$ 23
$ 45
* 493
-* 21
$ -5
* -220
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Federal Register/Vol. 68, No. 154/Monday, August 11, 2003/Proposed Rules
Table Vl-16b.- Incremental Net Benefits by Rule Alternative—Traditional COI
(Annualized Present Value, Smillions, 2000$)
Data
Set
Rule
Alternative
Annual
Costs
A
Annual
Benefits
B
incremental
Costs [1]
C
incremental
Benefits
Benefits
=D-C
' 3 Percent Discount Kate
ICR
A4
A3 - Preferred
A2
A1
$ 58
$ 111
$ 134
$ 361
$ 907
$ §67
$ 977
$ 369
$ 5B
$ 52
$ 23
$ 227
60
10
$ T3~
-
-2
ICRSSL
A4
A3 - Preferred
A2
A1
$ 37
•$- 73
$ 100
$ 361
$ 225
$ 253
$ 266
$ 305
$ 37
-5 37
'$ 26
$ 261
29
T5
37
» i
-
-2
ICRSSM
A4
A3 - Preferred
A2
A1
$ 44
$ 66
$ 113
$ 361
$ 432
$ 461
$ 498
$ 531
$ 44
$ 42
$ 26
$ 246
* *•"
$ ~~ 50
$ T7
33
$ j
-
-2
-1 7 Percent Discount Kate
ICR
A4
A3 - Preferred
A2
A1
$ 65
$ 121
$ 145
$ 336
$ 775
$ 826
$ 834
$ 645
$ 65
$ 56
$ 25
"$ 242
$ /YD
$ 5T
$ ~s
$ ^
-
-2
ICRSSL
A4
A3 - Preferred
A2
A1
$ 41
$ 81
$ 106
$ 366
$ 192
$ 218
$ 229
$ 260
^ 41
$ 40
$ 27
$ 279
24
$ T2
3T
> 1
-
-
- -2
ICRSSM
A4
A3 - Preferred
A2
A*
$ 43
$ 54
$ 122
$ 368
$ 369
$ 411
$ 425
$ 454
^ 48
S 47
$ 26
$ 235
$ Joy
42
14
$ 55
> o
•
-2
U
4
14
TTfT
00
IT
*.j
00
1
15
ID
16
Jl
ol
5
^4
•14
37
'The traditional COI only includes valuation for medical costs and lost work time (including some portion of unpaid
household production). The enhanced COI also factors in valuations for lost personal time (non-vrarktime such as
child care and homemaking (to the extent not covered by the traditional COI), time with family, and mcnafem. and
lost productivity at work on days when workers are ill but go to work anyway. Source: Chapter 8 of the LJ2ESWTR
Economic Analysis (USEPA 2003a)
BILLING CODE B560-50-C
G. Are There Benefits From the
Reduction of Co-Occurring
Contaminants?
This section presents information on
the unqualified benefits that will
accrue from removal of other
contaminants, primarily pathogens, due
to improved control of
Cryptosporidium. While the benefits
analysis for the LT2ESWTR only
includes reductions in illness and
mortality attributable to
Cryptosporidium, the LT2ESWTR is
expected to reduce exposure to other
parasitic protozoans that EPA regulates,
or is considering for future regulation.
For example, it is expected that the
LT2ESWTR will improve control of
Giardia lamblia, Cyclospora sp. and
members of the Microsporididea class,
seven genera (10 species) of which have
been recovered in humans (Mota et al.,
2000). In addition, greater
Cryptosporidium control may improve
control of the pathogenic bacteria and
viruses. Chemical contaminants such as
arsenic, DBFs and atrazine may also be
controlled, in part, by control of
Cryptosporidium, depending on the
technologies selected.
Giardia lamblia and Cyclospora sp.
are larger than Cryptosporidium, while
Microsporididea, bacteria, and the
viruses are smaller than
Cryptosporidium. The expected removal
of co-occurring microorganisms can
often be predicted for those treatment
unit processes whose removal efficiency
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47755
depends in part, or entirely, on the size
of the organism. For example, a study by
Goodrich and Lykins (1995) evaluating
bag filters showed that any microbe or
object greater than 4.5 microns in size
(the average size of Cryptosporidium}
would be subject to removal ranging
from 0.5 to 2.0 logs.
Although not directly dependent on
organism size, other treatment
technologies identified in the
LT2ESWTR should also provide
additional control of co-occurring
microbial pathogens. Membrane
processes that remove Cryptosporidium
are shown to achieve equivalent log
removal of Giardia under worst-case and
normal operating conditions (USEPA
2003c). Reduction in individual filter
turbidities will reduce concentrations of
other pathogens as well as
Cryptosporidium. For example, in Dutch
surface water, Giardia and
Cryptosporidium occurrence appeared
to correlate well with each other and for
the Rhine River, with turbidity
(Medema et al 2001). Thus, improved
control of Cryptosporidium should also
result in improved control of Giardia
lamblia.
Some membrane technologies that
might be installed to comply with the
LT2ESWTR can also reduce or eliminate
chemical contaminants including
arsenic, DBFs and atrazine. EPA has
recently finalized a rule to further
control arsenic levels in drinking-water
and is concurrently proposing the Stage
2 DBPR to address DBF control.
The extent to which the LT2ESWTR
can reduce the overall risk from other
contaminants has not been
quantitatively evaluated because of the
Agency's lack of data regarding the co-
occurrence among Cryptosporidium and
other microbial pathogens and
contaminants. Because of the difficulties
in establishing which systems would
have multiple problems, such as
microbial contamination, arsenic, and
DBFs or any combination of the three,
no estimate was made of the potential
cost savings from addressing more than
one contaminant simultaneously.
H. Are There Increased Risks From
Other Contaminants?
It is unlikely that the LT2ESWTR will
result in a significant increase in risk
from other contaminants. Many of the
options that systems will select to
comply with the LT2ESWTR, such as
UV, improved filtration performance,
and watershed control, do not form
DBFs, Other technologies that are
effective against Cryptosporidium, such
as ozone and chlorine dioxide, do form
DBFs. However, these DBFs are
currently regulated under the Stage 1
DBPR, and systems will have to comply
with these regulations when
implementing technologies to meet the
LT2ESWTR.
I. What Are The Effects of the
Contaminant on the Genera] Population
and Groups Within the Genera!
Populations That Are Identified as
Likely To Be at Greater Risk of Adverse
Health Effects?
Section II of this preamble discusses
the health effects associated with
Cryptosporidium on the general
population as well as the effects on
other sensitive sub-populations. In
addition, health effects associated with
children and pregnant women are
discussed in greater detail in section
VII.G of this preamble.
/. What Are the Uncertainties in the
Baseline, Risk, Benefit, and Cost
Estimates for the Proposed LT2ESWTR
as Well as the Quality and Extent of the
Information?
Today's proposal models the current
baseline risk from Cryptosporidium
exposure, as well as the reduction in
risk and the cost for various rule
options. There is uncertainty in the risk
calculation, the benefit estimate, the
cost estimates, and the interaction of
other upcoming rules. Section IV of the
proposed rule considers the uncertainty
with the risk estimates; however, a brief
summary of the major risk uncertainties
as they relate to benefit estimation is
provided next. In addition, the
LT2ESWTR EA has a more extensive
discussion of all of the uncertainties
(USEPA 2003a).
In addition, the Agency conducted
sensitivity analyses to address
uncertainty. The sensitivity analyses
focus on various occurrence, benefit and
cost factors that may have a significant
effect on the estimated impacts of the
rule. All of these sensitivity analyses are
explained in more detail in the EA for
the LT2ESWTR (USEPA 2003a).
One area of uncertainty is associated
with the estimate of Cryptosporidium
occurrence on a national basis. The
Information Collection Rule plant-mean
data were higher than the ICRSS
medium or large system plant-mean
data at the 90th percentile. The reasons
for these differing results are not well
understood but may stem from
differences in the populations sampled,
year-to-year variation in occurrence, and
systematic differences in the sampling
and measurement methods employed.
These data suggest that
Cryptosporidium levels are relatively
low in most water sources, but there is
a subset of sources with significantly
higher concentrations. Additional
uncertainty is associated with
estimating finished water occurrence
because the analysis is based on
assumptions about treatment plant
performance. To account for these
uncertainties, the Agency used Monte
CarJo simulation models that allow
substantial variation in each estimate
and computed finished water
occurrence values based on statistical
sampling of the variable estimates.
The risk associated with finished
water occurrence is of lesser uncertainty
than is typical for many contaminants
because the health effects are measured
based on Cryptosporidium challenge
studies to human volunteer populations.
Nevertheless, there is significant
uncertainty about the dose-response
associated with Cryptosporidium
because there exists considerable
differences in infectivity among the
various tested Cryptosporidium parvum
isolates. As described in section III.B,
the Agency accounted for these
differences using Monte Carlo
simulations that randomly sampled
from infectivity distributions for.the
three tested isolates. The different
simulations were designed to account
for the limited number of challenge
studies and the variability in the
infectivity of the isolates themselves. In
addition, because the Cryptosporidium
dosing levels in the human feeding
studies were above typical drinking
water exposure levels (e.g., one oocyst),
there remains significant uncertainty
that could not be quantified into the
analysis.
While all of the significant costs of
today's proposed rule have been
identified by EPA, there are
uncertainties about some of the
estimates. However, the Agency
explored the impact of the uncertainties
that might have the greatest impact by
conducting sensitivity analyses and
using Monte Carlo techniques. For
example, section VI.D.2.f of today's rule
explores the impact of influent bromide
levels on technology selection. As
shown in the EA for this rule, the
impact of higher influent bromide levels
will not have a significant impact on the
rule's costs. In addition, subsection 6.12
of the EA summarizes other cost
uncertainties including the Agency's
inability to include some lower cost
toolbox options in the cost analysis
(USEPA 2003a).
Last, EPA has recently finalized new
regulations for arsenic, radon,
Cryptosporidium in small surface water
systems, and filter backwash in all
system sizes (LTlESWTR and Filter
Backwash Rule); proposed a rule for
microbials in ground water systems
(Ground Water Rule); and is
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Federal Register/Vol. 68, No. 154/Monday. August 11. 2003/Proposed Rules
concurrently proposing additional
control of disinfection byproducts
(Stage 2 Disinfection Byproducts Rule).
These rules may have overlapping
impacts on some drinking water systems
but the extent is not possible to estimate
because of lack of information on co-
occurrence. However, it is possible for
a system to choose treatment
technologies that would address
multiple contaminants. Therefore, while
the total cost impact of these drinking
water rules is uncertain, it is most likely
less than the estimated total cost of all
individual rules combined.
K. What is the Benefit/Cost
Determination for the Proposed
LT2ESWTR?
The Agency has determined that the
benefits of the proposed LT2ESWTR
justify the costs. As discussed in section
VI.C, the proposed rule provides a large
reduction in endemic cryptosporidiosis
illness and mortalities. More stringent
alternatives provide greater reductions
but at higher costs. Alternative Al
provides the greatest overall reduction
in illnesses and mortalities but the
incremental benefits between this
option and the preferred option are
relatively small while the incremental
costs are significant. In addition, the
preferred regulatory option, unlike
option Al, specifically targets those
systems whose source water requires
higher levels of treatment.
Tables VI-17a and VI-17b present net
benefits for the four regulatory
alternatives that were evaluated.
Generally, analysis of net benefits is
used to identify alternatives where
benefits exceed costs, as well as the
alternative that maximizes net benefits.
However, as with the analysis of
incremental net benefits discussed
previously, the usefulness of this
analysis in evaluating regulatory
alternatives for the LT2ESWTR is
limited because many benefits from this
rule are un-quantified and non-
monetized. Analyses of net benefits
should consider both quantified and
non-quantified (where possible) benefits
and costs.
Also, as noted earlier, the regulatory
alternatives considered for the
LT2ESWTR vary both in the population
that experiences benefits and costs (i.e.,
risk bin boundaries) and the magnitude
of the benefits and costs (i.e., treatment
requirements). Consequently, the more
stringent regulatory alternatives provide
benefits to population groups that do
not experience any benefit under less
stringent alternatives.
As shown by Tables VI-17a and VI-
17b, net benefits are positive for all four
regulatory alternatives evaluated. With
the enhanced COI [Table VI-17a), net
benefits are highest for the Preferred
Alternative, A3, under the majority of
occurrence distributions and discount
rates evaluated. When the traditional
COI (Table VI-17b) is used, the
Preferred Alternative has the highest net
benefits at a three percent discount rate
for the two of the occurrence
distributions, the Information Collection
Rule and ICRSSM, while the least
stringent alternative, A4, is highest for
the ICRSSL. At a seven percent discount
rate, A4 maximizes net benefits under
all occurrence distributions.
Table VI-17a.— Mean Net Benefits by
Rule Option—Enhanced COI (Smillions,
2000$)
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47757
Data
Set
ICR
Rule
Alternative
A1
A2
A3 - Preferred
A4
Annualized Value
3%, 25 Years
$ 1,121
$ 1,327
$ 1 ,335
$ 1,290
7%, 25 Years
$ 873
$ 1,098
$ 1,109
$ 1,083
ICRSSL
A1
A2
A3 - Preferred
A4
$ 96
$ 298
$ 300
$ 291
$ 1
$ 230
$ 237
$ 238
ICRSSM
A1
A2
A3 - Preferred
A4
$ 435
$ t>3U
$ o^y
$ 592
$ 289
$ 509
$ M4
$ 403
Table VM7b.~ Mean Net Benefits by Rule Option—Traditional COI ($millions,
2000$)
Data
Set
ICR
Rule
Alternative
A1
A2
A3 - Preferred
A4
Annualized value
3%, 25 Years
$ 628
$ 843
$ Ubti
$ two
7%, 25 Years
$ 457
$ 688
$ 705
$ /1U
ICRSSL
M
A2
A3 - Preferred
A4
$ -56
$ 168
$ 180
$ itse
$ -128
$ 120
$ 135
3> ibl
ICRSSM
A1
A2
A3 - Preferred
A4
$ 170
$ 386
$ -&b
$ 388
$ 66
$ 303
$ 317
$ 3*H
'The traditional COI only includes valuation for medical costs and lost work time (including some portion of unpaid
household production). The enhanced COI also factors in valuations for lost personal time (non-worktime) such as
child care and homemaking (to the extent not covered by the traditional COt), time with family, and recreation, and
lost productivity at work on days when workers are ill but go to work anyway. Source: Chapter 8 of the LT2ESWTR
Economic Analysis (USEPA 2003a)
BILLING CODE 6560-50-C
In addition to the net benefits of the
proposed LT2ESWTR, the Agency used
several other techniques to compare
costs and benefits. For example, EPA
calculated the cost of the rule per case
avoided. Table VI-18 shows both the
cost of the rule per illness avoided and
cost of the rule per death avoided. This
cost effectiveness measure is another
way of examining the benefits and costs
of the rule but should not be used to
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Federal Register/Vol. 68, No. 154/Monday, August 11, 2003/Proposed Rules
compare alternatives because an
alternative with the lowest cost per
illness/death avoided may not result in
the highest net benefits. With the
exception of alternative Al, the rule
options look favorable from a cost
effectiveness analysis when you
compare them to both the average cost
of cryptosporidiosis illness ($745 and
$245 for the two COI approaches) and
the mean value of a death avoided—
approximately $7 million dollars.
Additional information about this
analysis and other methods of
comparing benefits and costs can be
found in chapter 8 to the LT2ESWTR
EA (USEPA 2003a).
TABLE VI-18.—COST PER ILLNESS OR DEATH AVOIDED
Data set
• Rule alternative
A1
A2
A3 — Preferred
A4 ,
A1
A2
A4
A1
A2
A4
Cost per illness
avoided ($)
3%
339
128
107
62
1,098
356
282
165
631
213
170
99
7%
244
93
78
45
789
259
208
122
453
155
125
73
Cost per death
avoided {$ mil-
lions, 2000$)
3%
2.5
0.9
0.8
0.4
8.0
2.5
1.9
1.1
4.6
1.6
1.2
0.7
7%
1.8
0.7
0.6
0.3
5.7
1.8
1.4
0.8
3.3
1.1
0.9
0.5
Source: Chapter 8 of the LT2ESWTR Economic Analysis (USEPA 2003a)
L. Request for Comment
The Agency requests comment on all
aspects of the proposed rule's economic
impact analysis. Specifically, EPA seeks
input into the following issues:
• Both of the methodologies for
valuing non-fatal cryptosporidiosis and
the use of a real income growth factor
to adjust these estimates for the years
2008 through 2027;
• How can the Agency fully
incorporate all toolbox options into the
economic analysis?
• How can the Agency estimate the
potential benefits from reduced
epidemic outbreaks of
cryptosporidiosis?
VII. Statutory and Executive Order
Reviews
A. 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, or 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 entitlements, 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.
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. The
Information Collection Request (ICR)
document prepared by EPA has been
assigned EPA ICR number 2097.01.
The information collected as a result
of this rule will allow the States and
EPA to determine appropriate
requirements for specific systems, and
to evaluate compliance with the rule.
For the first 3 years after LT2ESWTR
promulgation, the major information
requirements concern monitoring
activities and compliance tracking. The
information collection requirements are
mandatory (part 141), and the
information collected is not
confidential.
The estimate of annual average
burden hours for the LT2ESWTR during
the first three years following
promulgation is 145,854 hours. The
annual average cost estimate is $3.9
million for labor and $9.8 million per
year for operation and maintenance
including lab costs (which is a purchase
of service). The burden hours per
response is 1.47 hours and the cost per
response is $138.12. The frequency of
response (average responses per
respondent) is 39, annually. The
estimated number of likely respondents
is 2,560 (the product of burden hours
per response, frequency, and
respondents does not total the annual
average burden hours due to rounding).
Note that the burden hour estimates for
the first 3-year cycle include large
system but not small system monitoring.
Conversely, burden estimate for the
second 3-year cycle will include small
system monitoring but not large system,
which will have been completed by
then.
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
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47759
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.
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 in 40
CFR are listed in 40 CFR part 9.
To comment on the Agency's need for
this information, the accuracy of the
provided burden estimates, and any
suggested methods for minimizing
respondent burden, including the use of
automated collection techniques, EPA
has established a public docket for this
rule, which includes this ICR, under
Docket ID No. OW-2002-0039. Submit
any comments related to the ICR for this
proposed rule to EPA and OMB. See
ADDRESSES section at the beginning of
this notice for where to submit
comments to EPA. Send comments to
OMB at the Office of Information and
Regulatory Affairs, Office of
Management and Budget, 725 17th
Street, NW., Washington, DC 20503,
Attention: Desk Office for EPA. Since
OMB is required to make a decision
concerning the ICR between 30 and 60
days after August 11, 2003, a comment
to OMB is best assured of having its full
effect if OMB receives it by September
10, 2003. The final rule will respond to
any OMB or public comments on the
information collection requirements
contained in this proposal.
C. Regulatory Flexibility Act
The Regulatory Flexibility Act (RFA)
generally requires an agency to prepare
a regulatory flexibility analysis for any
rule subject to notice and comment
rulemaking requirements under the
Administrative Procedure Act or 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.
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 (3H5). In addition to
the above, to establish an alternative
small business definition, agencies must
consult with SBA's Chief Council for
Advocacy.
For purposes of assessing the impacts
of today's proposed rule on small
entities, EPA considered small entities
to be public water systems serving
10,000 or fewer 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. In accordance with the RFA
requirements, EPA proposed using this
alternative definition in the Federal
Register, (63 FR 7620, February 13,
1998), requested public comment,
consulted with the Small Business
Administration (SBA), and expressed its
intention to use the alternative
definition for all future drinking water
regulations in the Consumer Confidence
Reports regulation (63 FR 44511, August
19,1998). As stated in that final rule,
the alternative definition is applied to
this proposed regulation.
After considering the economic
impacts of today's proposed rule on
small entities, I certify that this action
will not have a significant economic
impact on a substantial number of small
entities. We have determined that 274
small systems, which are 2.32% of the
11,820 small systems regulated by the
LT2ESWTR, will experience an impact
of one percent or greater of average
annual revenues; further, 31 systems,
which are 0.26% of the systems
regulated by this rule, will experience
an impact of three percent or greater of
average annual revenues (see Table VII-
1).
TABLE VIM.—ANNUALIZED COMPLIANCE COST AS A PERCENTAGE OF REVENUES FOR SMALL ENTITIES ($2000)
Entity by system size
All Small Entities
Number of smalt
systems
(Percent)
A
5,910 50
4,846 41
1,064 9
11,820 100
Average annual
estimated
revenuses per
system ($)
B
2,434,200
2,391,978
4,446,165
2,597,966
Systems experiencing
costs of >% their revenues
Percent of
sustem
E
2.4
2.4
1.2
2.3
Number of
systems
F=A'E
140
115
13
274
Systems experiencing
costs of >% of their reve-
nues
Percent of
systems
G
0.3
0.3
0.1
0.3
Number of
systems
H=A*G
15
13
1
31
Note- Detail may not add due to independent rounding. Data are based on the means of the highest modeled distributions us.ng Information
Collection Rule occurrence data set. Costs are discounted at 3 percent, summed to present value, and annualized over 25 years. Source: Chap-
ter 7 of the LT2ESWTR EA {USEPA 2003a).
The LT2ESWTR contains provisions
that will affect systems serving fewer
than 10,000 people that use surface
water or GWUDI as a source. In order to
meet the LT2ESWTR requirements,
approximately 1,382 to 2,127 small
systems would need to make capital
improvements. Impacts on small entities
are described in more detail in Chapters
6 and 7 of the Economic Analysis for the
LT2ESWTR (USEPA 2003a). Table VII-
2 shows the annual compliance costs of
the LT2ESWTR on the small entities by
system size and type based on a three
percent discount rate (other estimates
based on different data sets and
discount rates produce lower costs).
EPA has determined that in each size
category, fewer than 20% of systems
and fewer than 1000 systems will
experience an impact of one percent or
greater of average annual revenues
(USEPA 2003a).
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Federal Register/Vol. 68, No. 154/Monday, August 11, 2003/Proposed Rules
TABLE VI1-2.—ANNUAL COMPLIANCE COSTS FOR THE PROPOSED LT2ESWTR BY SYSTEM SIZE AND TYPE
[SMillions, 2000$]
System type
All systems
System size (population served)
<100
$0.46
1.00
1.45
101-500
$0.88
0.71
1.59
501-1,000
$0.94
0.22
1.07
1,001-
3,300
$2.62
0.31
2.92
3,301-
10,000
$5.57
0.36
5.93
Total
$10.37
2.60
12.97
Note: Results are based on .the mean of the Information Collection Rule Cryptosporidium occurrence distribution. Costs are annuatized at a
three percent discount rate.
Source; Appendix D and Q of the LT2ESWTR EA (USEPA 2003a).
Although this proposed rule will not
have a significant economic impact on
a substantial number of small entities,
EPA nonetheless has tried to reduce the
impact of this rule on small entities. The
LT2ESWTR contains a number of
provisions to minimize the impact of
the rule on systems generally, and on
small systems in particular. The risk-
targeted approach of the LT2ESWTR
will impose additional treatment
requirements only on the subset of
systems with the highest vulnerability
to Cryptosporidium, as indicated by
source water pathogen levels. This
approach will spare the majority of
systems from the cost of installing
additional treatment. Also, development
of the microbial toolbox under the
LT2ESWTR will provide both large and
small systems with broad flexibility in
selecting cost-effective compliance
options to meet additional treatment
requirements.
Small systems will monitor for E, coli
as a screening analysis for .source waters
with low levels of fecal contamination.
Cryptosporidium monitoring will only
be required of small systems if they
exceed the E. coli trigger value. Because
E. coli analysis is much cheaper than
Cryptosporidium analysis, the use of E.
coli as a screen will significantly reduce
monitoring costs for the majority of
small systems. In order to allow EPA to
review Cryptosporidiutn indicator
relationships in large system monitoring
data, small systems will not be required
to initiate their monitoring until large
system monitoring has been completed.
This will provide small systems with
additional time to become familiar with
the rule and to prepare for monitoring
and other compliance activities.
Funding would be available from
programs administered by EPA and
other Federal agencies to assist small
public water systems (PWSs) in
complying with the LT2ESWTR. The
Drinking Water State Revolving Fund
(DWSRF) assists PWSs with financing
the costs of infrastructure needed to
achieve or maintain compliance with
SDWA requirements. Through the
DWSRF, EPA awards capitalization
grants to States, which in turn can
provide low-cost loans and other types
of assistance to eligible PWSs. Loans
made under the program can have
interest rates between 0 percent and
market rate and repayment terms of up
to 20 years. States prioritize funding
based on projects that address the most
serious risks to human health and assist
systems most in need. Congress
provided $1.275 billion for the DWSRF
program in fiscal year 1997, and has
provided an additional $3.145 billion
for the DWSRF program for fiscal years
1998 through 2001.
The DWSRF places an emphasis on
small and disadvantaged communities.
States must provide a minimum of 15%
of the available funds for loans to small
communities. A State has the option of
providing up to 30% of the grant
awarded to the State to furnish
additional assistance to State-defined
disadvantaged communities. This
assistance can take the form of lower
interest rates, principal forgiveness, or
negative interest rate loans. The State
may also extend repayment terms of
loans for disadvantaged communities to
up to 30 years. A State can set aside up
to 2% of the grant to provide technical
assistance to systems serving
communities with populations fewer
than 10,000.
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
Development Block Grant (CDBG)
program. RUS provides loans,
guaranteed loans, and grants to improve,
repair, or construct water supply and
distribution systems in rural areas and
towns of up to 10,000 people. In fiscal
year 2002, RUS had over $1.5 billion of
available funds for water and
environmental programs. The CDBG
program includes direct grants to States,
which in turn are awarded to smaller
communities, rural areas, and colon as
in Arizona, California, New Mexico, and
Texas and direct grants to U.S.
territories and trusts. The CDBG budget
for fiscal year 2002 totaled over $4.3
billion.
Although not required by the RFA to
convene a Small Business Advocacy
Review (SBAR) Panel because EPA
determined that this proposal would not
have a significant economic impact on
a substantial number of small entities,
EPA did convene a panel to obtain
advice and recommendations from
representatives of the small entities
potentially subject to this rule's
requirements.
Before convening the SBAR Panel,
EPA consulted with a group of 24 small
entity stakeholders likely to be impacted
by the LT2ESWTR and who were asked
to serve as Small Entity Representatives
(SERs) after the Panel was convened.
The small entity stakeholders included
small system operators, local
government representatives, and
representatives of small nonprofit
organizations. The small entity
stakeholders were provided with
background information on SDWA and
potential alternatives for the LT2ESWTR
in preparation for teleconferences on
January 28, 2000, February 25, 2000,
and April 7, 2000. This information
package included data on preliminary
unit costs for treatment enhancements
under consideration.
During these three conference calls,
the information that had been provided
to the small entity stakeholders was
discussed and EPA responded to
questions and recorded initial
comments. Following the three calls, the
small entity stakeholders were asked to
provide input on the potential impacts
of the rule from their perspective. Seven
small entity stakeholders provided
written comments on these materials.
The SBAR Panel convened on April
25, 2000. The small entity stakeholders
comments were provided to the SBAR
Panel when it convened. After a
teleconference between the SERs and
the SBAR Panel on May 25, 2000, the
SERs were invited to provide additional
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47761
comments on the information provided.
Seven SERs provided additional
comments on the rule components.
The SBAR Panel's report, Final Report
of the Small Business Advocacy Review
Panel on Stage 2 Disinfectants and
Disinfection Byproducts Rule (Stage 2
DBPR) and Long Term 2 Enhanced
Surface Water Treatment Rule
(LT2ESWTR) (USEPA 2000f), the SERs
comments on the LT2ESWTR, and the
background information provided to the
SBAR Panel and the SERs are available
for review in the docket for today's
proposal (http://www.epa.gov.edocket/).
In general, the SERs who were
consulted on the LT2ESWTR were
concerned about the impact of these
proposed rules on small water systems,
the ability of small systems to acquire
the technical and financial capability to
implement requirements while
maintaining flexibility to tailor the
requirements to their needs, and the
limitations of small systems. The SBAR
Panel evaluated information and small-
entity comments on issues related to the
impact of the LT2ESWTR.
The LT2ESWTR takes into
consideration the recordkeeping and
reporting concerns identified by the
SBAR Panel and the SERs. The SBAR
Panel recommended that EPA evaluate
ways to minimize the recordkeeping
and reporting burdens under the rule by
ensuring that the States have
appropriate capacity for rule
implementation, and that EPA provide
as much monitoring flexibility as
possible to small systems. EPA believes
that the continuity with the IESWTR
and LTlESWTR was maintained to the
extent possible to ease the transition to
the LT2ESWTR, especially for small
systems. The LT2ESWTR builds on the
protection afforded under the IESWTR
and LTlESWTR, while minimizing the
impact on small systems by using a risk-
targeted approach (i.e., source water
monitoring) to identify systems that are
still at risk from Cryptosporidium
exposure.
The SBAR Panel noted the concern of
several SERs that flexibility be provided
in the compliance schedule of the rule.
SERs commented on the technical and
financial limitations of some small
systems, 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 SBAR
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 SDWA.
EPA has concluded that the proposed
schedule for the LT2ESWTR provides
sufficient time for small systems to
achieve compliance. The schedule for
small system monitoring and
compliance with additional treatment
requirements lags behind the schedule
for large systems. The basis for the
lagging schedule for small systems is
that it allows EPA to confirm or refine
the E. coli screening criteria that small
systems will use to reduce monitoring
costs. However, the lagging schedule
also provides greater time for small
systems to become knowledgeable about
the LT2ESWTR, including the new
monitoring requirements, and to become
familiar with innovative technologies,
like UV, that may be used by some small
systems to meet additional treatment
requirements.
Some SERs emphasized that EPA
needs to maintain an appropriate
balance between control of known
microbial risks through adequate
disinfection and for the more uncertain
risks that may be associated with DBFs.
The SBAR Panel did not foresee any
potential conflict between rules
regulating control of microbial
contaminants and those regulating
DBFs. EPA also believes that today's
proposal and the accompanying
proposed Stage 2 DBPR achieve an
appropriate balance between microbial
and DBF risks. The profiling and
benchmarking requirements described
in section IV.D of this preamble will
ensure that systems maintain protection
against pathogens as they make
treatment changes to control the
formation of DBFs.
The SBAR Panel considered a wide
range of options and regulatory
alternatives for providing small
businesses with flexibility in complying
with the LT2ESWTR. The SBAR Panel
was concerned with the option of an
across-the-board additional
Cryptosporidium inactivation
requirement because of the potential
high cost to small systems and the
uncertainty regarding the extent to
which implementation of the
LTlESWTR will adequately address
Cryptosporidium contamination at small
systems. The SBAR Panel noted that, at
the time, the Stage 2 M-DBP Federal
Advisory Committee was exploring a
targeted approach to Cryptosporidium
control based on limited monitoring and
system assessment, which would
identify a subset of vulnerable systems
to provide additional treatment in the
range of 0,5-to 2.5-log reduction.
Further, this approach would allow E.
coli monitoring in lieu of
Cryptosporidium monitoring as a
screening device for small systems. The
SBAR Panel was also encouraged by
recent developments suggesting that UV
is a viable, cost-effective means of
fulfilling any additional inactivation
requirements.
The SBAR Panel recommended that,
in developing any additional
inactivation requirements based on a
targeted approach, EPA carefully
consider the potential impacts on small
systems and attempt to structure the
regulatory requirements in a way that
would minimize burden on this group.
The SBAR Panel supported E. coli as an
indicator parameter if additional
monitoring is required. The SBAR Panel
further recommended that, among the
options EPA analyzes, the Agency also
evaluate the option of not imposing any
additional Cryptosporidium control
requirements on small systems at this
time, as it considers various options to
address microbial concerns. Under this
option, EPA would evaluate the effects
of LTlESWTR, once implemented, and
then consider whether to impose
additional requirements during its next
6-year review of the standard, as
required by SDWA.
EPA considered these
recommendations and has concluded
that available information on the health
risk associated with Cryptosporidium in
drinking water warrant moving forward
with today's proposal to address higher
risk systems. In developing the
proposed LT2ESWTR, EPA has
implemented the Advisory Committee's
recommendations to minimize burden
on small systems. Specifically, the risk-
targeted treatment requirements will
substantially reduce overall costs for
small systems in comparison to
requiring additional treatment by all
systems, and the use of E. coli screening
will allow most small systems to avoid
the cost of Cryptosporidium monitoring.
Consequently, the Agency has
concluded that today's proposal
achieves an appropriate balance
between public health protection and
limiting the economic burden imposed
on small entities.
We continue to be interested in the
potential impacts of the proposed rule
on small entities and welcome
comments on issues related to such
impacts.
D. 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 section 202 of UMRA,
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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 to 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 notifying
potentially affected small governments,
enabling officials of 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
contains a Federal mandate that may
result in expenditures of $100 million or
more for State, local, and Tribal
governments, in the aggregate, or the
private sector in any one year.
Accordingly, EPA has prepared under
section 202 of the UMRA a written
statement which is summarized in this
section. Table VII-3 illustrates the
annualized public and private costs for
the LT2ESWTR.
TABLE VII-3.—PUBLIC AND PRIVATE COSTS OF THE PROPOSED LT2ESWTR
Total Costs
Range of annualized costs (Mil-
lion $, 2000$)
3% Discount
rate
$45.7-69.0
0.9-1.0
0.1-0.2
46.7-70.1
26.8-40.4
73.5-110.5
7% Discount
rate
$50.2-75.2
1.2-1.2
0.1-0.2
51.5-76.6
29.4-44.1
80.9-120.7
Percent of
total cost
62.2-62.4
1.3-0.9
0.1-0.1
63.6-63.4
36.4-36.6
100.0-100.0
The,-..
DetaShriay ncrt'aSd'due to independent rounding.
Source: The LT2ESWTR Economic Analysis (USEPA 2003a).
A more detailed description of this
analysis is presented in Economic
Analysis for the LT2ESWTR {USEPA
2003a).
a. Authorizing legislation. As noted in
section II, today's proposed rule is
promulgated pursuant to section 1412
(b)(l){A) of the Safe Drinking Water Act
(SDWA), as amended in 1996, which
directs EPA to promulgate a national
primary drinking water regulation for a
contaminant if EPA determines that the
contaminant may have an adverse effect
on the health of persons, occurs in
public water systems with a frequency
and at levels of public health concern,
and regulation presents a meaningful
opportunity for health risk reduction.
b. Cost-benefit analysis. Section VI of
this preamble discusses the cost and
benefits associated with the LT2ESWTR
Details are presented in the Economic
Analysis for the LT2ESTWR (USEPA
2003a). For the LT2ESWTR proposal,
EPA quantified costs and benefits for
four regulatory alternatives. The four
alternatives are described in section VI.
Table VII-4 summarizes the range of
annual costs and benefits for each
alternative.
TABLE VII-4.—ANNUAL BENEFITS AND COSTS OF RULE ALTERNATIVES
[SMillion]
Regulatory Alternative
Alternative A4 •_
Enhanced COI
range of
annualized
benefits (3%)
$457-1,492
397-1,461
374-1,445
328-1,349
Traditional
COI range of
annualized
benefits (3%)
$305-989
268-977
253-967
225-907
Enahnced COI
range of
annualized
benefits (7%)
$389-1,260
338-1,243
318-1,230
279-1,148
Tradition COI
range of
annuitized
benefits (7%)
$260-845
229-834
216-826
192-775
Range of
annualized
costs (3%)
$361
100-134
73-111
37-59
Range of
annualized
costs (7%)
$388
108-145
81-121
41-65
Source: The LT2ESWTR Economic Analysis (USEPA 2003a).
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 earlier and discussed in more
detail in section VI of this preamble,
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47763
accurately characterize future
compliance costs of the proposed rule.
In analyzing disproportionate
impacts, the Agency considered the
impact on (1) different regions of the
United States, (2) State, local, and Tribal
governments, (3) urban, rural and other
types of communities, and (4) any
segment of the private sector. This
analysis is presented in section 7 of
Economic Analysis for the LT2ESWTR
(USEPA 2003a).
EPA has concluded that the
LT2ESWTR will not cause a
disproportionate budgetary effect. This
rule imposes the same requirements on
systems nationally and does not
disproportionately affect any segment.
This rule will treat similarly situated
systems (in terms of size, water quality,
available data, installed technology, and
presence of uncovered finished storage
facilities) in similar (proportionate)
ways, without regard to geographic
location, type of community, or segment
of industry. The LT2ESWTR is a rule
where requirements are proportionate to
risk. Although some groups may have
differing budgetary effects as a result of
LT2ESWTR, those costs are proportional
to the need for greater information
(monitoring) and risk posed (degree of
treatment required). The variation in
cost between large and small systems is
due to economies of scale (a larger
system can distribute cost across more
customers). Regions will have varying
impacts due to the number of affected
systems.
d. Macro-economic effects. 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 2000,
real GDP was $9,224 billion, so a rule
would have to cost at least $23 billion
to have a measurable effect. A regulation
with a smaller aggregate effect is
unlikely to have any measurable impact
unless it is highly focused on a
particular geographic region or
economic sector.
The macro-economic effects on the
national economy from the LT2ESWTR
should not have a measurable effect
because the total annual costs for the
proposed option range from $73 million
to $111 million based on median
Cryptosporidium occurrence
distributions from the ICRSSL and
Information Collection Rule data sets
and a discount rate of 3 percent ($81 to
$121 million at a 7 percent discount
rate). These annualized figures will
remain constant over the 25-year
implementation period that was
evaluated, while GDP will probably
continue to rise. Thus, LT2ESWTR costs
measures as a percentage of the national
GDP will only decline over time. Costs
will not be highly focused on a
particular geographic region or sector.
e. Summary of EPA 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 consultations with
the governmental entities affected by
this rule. A variety of stakeholders,
including small governments, were
provided the opportunity for timely and
meaningful participation in the
regulatory development process. EPA
used these opportunities to notify
potentially affected governments of
regulatory requirements being
considered.
The Stage 2 M-DBP Federal Advisory
Committee included representatives
from State government (Association of
State Drinking Water Administrators,
Environmental Commissioners of
States), local government (National
League of Cities), and Tribes (All Indian
Pueblo Council (AIPC)). Government
and Tribal representatives on the
Advisory Committee were generally
concerned with ensuring that drinking
water regulations are adequately
protective of public health and that any
additional public health expenditures
due to new regulations achieve
significant risk reduction. The proposed
LT2ESWTR reflects the consensus
recommendations of the Advisory
Committee, as stated in the Agreement
in Principle (65 FR 83015, December 29,
2000). Consequently, EPA believes that
the risk-targeted approach for additional
Cryptosporidium treatment
requirements and other provisions in
today's proposal satisfies the concerns
of the government and Tribal
representatives on the Advisory
Committee.
As described in section VII,C of this
preamble, the Agency 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 to address the concerns of
small entities, including small local
governments specifically. Small entity
representatives (SERs) to the SBAR
panel, including representatives of
small local governments, were
concerned about the cost of the rule, the
technical capability of small systems to
implement requirements, and flexibility
in regulatory requirements and in the
compliance schedule. SERs also
emphasized that EPA needs to balance
the control of known microbial risks
with the risks associated with DBFs.
Today's proposal is responsive to
these concerns, as stated in section
VII.C. The LT2ESWTR will impose costs
for additional treatment on only the
fraction of systems identified through
monitoring as being at higher risk, and
overall monitoring costs for small
systems will be greatly reduced through
use of the E. coll screening to waive
small systems from Cryptosporidium
monitoring. The microbial toolbox of
treatment options will provide
significant flexibility to systems to
identify cost-effective solutions for
meeting additional Cryptosporidium
treatment requirements. The compliance
schedule for small systems is delayed in
relation to large systems, which will
allow small systems additional time to
become knowledgeable about and
prepare to implement the LT2ESWTR.
The intent of the proposed disinfection
profiling provisions is to ensure that
when systems make treatment changes
to control DBF formation, they maintain
protection against pathogens.
EPA held a meeting on the
LT2ESWTR in February 2001 with
representatives of State and local
governments. Representatives of the
following organizations attended:
Association of State Drinking Water
Administrators (ASDWA), the National
Governors' Association (NGA), the
National Conference of State
Legislatures (NCSL), the International
City/County Management Association
(ICMA), the National League of Cities
(NLC), the County Executives of
America, and health departments.
Representatives asked questions
regarding how Cryptosporidium gets
into the water, whether EPA would add
laboratory approval for Cryptosporidium
to State certification programs, the
effectiveness of ozone and UV, and the
development of ambient water quality
criteria for Cryptosporidium.
EPA has largely addressed these
questions in this preamble. Section II
characterizes sources of
Cryptosporidium. As described in
section IV.K, EPA is currently carrying
out a laboratory approval program for
Cryptosporidium analyses but expects
that this will be included in State
laboratory certification programs in the
future. In section IV.C., EPA describes
the effectiveness of ozone and UV for
Cryptosporidium inactivation and
provides criteria for how these
technologies may be used to comply
with the treatment requirements in
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today's proposal. The Agency is
currently exploring the development of
ambient water quality criteria for
Cryptospondium, but such criteria are
not available at this time and are not
included in today's proposal.
In addition to the Tribal
representative on the Advisory
Committee, EPA conducted outreach
and consultation with Tribal
representatives on a number of
occasions regarding the LT2ESWTR.
EPA presented the LT2ESWTR at the
following forums: the 16th Annual
Consumer Conference of the National
Indian Health Board, which included
over 900 representatives of Tribes across
the nation; the annual conference of the
National Tribal Environmental Council,
at which over 100 Tribes were
represented; and the 1999 EPA/Inter-
Tribal Council of Arizona, which
included representatives from 15 Tribes.
EPA also sent the presentation materials
used in the first two meetings and
meeting summaries to over 500 Tribes
and Tribal organizations.
Fact sheets describing the
requirements of the LT2ESWTR and
requesting Tribal input were distributed
at an annual EPA Tribal meeting in San
Francisco and at a Native American
Water Works Association meeting in
Scottsdale, Arizona. EPA also worked
through its Regional Indian
Coordinators and the National Tribal
Operations Committee to raise
awareness of the development of the
proposed rule. EPA mailed all Federal
Tribes LT2ESWTR fact sheets in
November 2000. The Tribal
representative to the Advisory
Committee also presented the Stage 2
Agreement in Principle prior to
signature in at least one political forum
for various Tribes not affiliated with
AIPC.
EPA held a teleconference in January
2002 with 12 Tribal representatives and
four Regional Tribal Program
Coordinators. Prior to the
teleconference, EPA sent invitations to
all Federal Tribes, along with a fact
sheet explaining the LT2ESWTR.
Through this consultation, Tribal
representatives expressed concern about
implementing new regulations without
additional funding sources. However,
they also stated that the LT2ESWTR
would have a benefit, and asserted that
people served by small systems should
receive equivalent public health
protection. Questions were asked
regarding the impact of the rule (e.g.,
number of Tribal surface water systems)
and the date for finalizing the rule. The
Tribal representative to the M-DBP
Advisory Committee advocated that risk
mitigation plans for uncovered finished
water storage facilities should account
for cultural uses by Tribes.
In response to the concerns expressed
by Tribal representatives, EPA noted
that the LT2ESWTR proposal is
designed to minimize costs by targeting
higher risk systems, and includes other
provisions, described earlier, to reduce
burden. Moreover, the projected benefits
of the rule substantially exceed costs.
EPA also explained that capital projects
related to the rule would be eligible for
Federal funding sources, such as the
Drinking Water State Revolving Fund,
due to the health risks associated with
Cryptospondium. The LT2ESWTR
Economic Analysis {USEPA 2003a)
provides an analysis of the impact of the
LT2ESWTR on Tribes. EPA has
identified 67 Tribal water systems that
would be subject to the LT2ESWTR.
In addition to these direct
consultations with State, local, and
Tribal governments, EPA posted a pre-
proposal draft of the LT2ESWTR
proposal on an EPA Internet site (http:/
/www.epa.gov/safewaterf) in November
2001. EPA received comments on this
pre-proposal draft from ASDWA and six
States, several public water systems
owned by local governments, as well as
private water systems, laboratories, and
other stakeholders. Among the concerns
raised by commenters representing State
and local governments were the
following: early implementation of
monitoring by large systems; flexibility
for States in awarding treatment credits
to different Cryptospondium control
technologies; and the added burden of
the rule on systems and States.
EPA has addressed these concerns in
developing the LT2ESWTR proposal. As
described in section IV.], EPA is
planning to directly implement the large
system monitoring requirements that
occur during the first 2.5 years after
promulgation. The planned approach is
similar to that used for the UCMR,
including an electronic data reporting
system for storing monitoring results
and tracking compliance. With this
approach, States will be able to access
data reported by their systems, thereby
allowing States to exercise oversight of
their systems during early
implementation if they chose. However,
EPA will take primary responsibility for
providing technical assistance to
systems and assessing compliance with
monitoring requirements.
In regard to treatment credit for
Cryptospondium control technologies,
the Agency has made substantial efforts
to ensure that the criteria in today's
proposal are based on the best available
data. EPA has worked in partnership
with industry and researchers to gather
information, and proposed criteria for
several microbial toolbox options reflect
comments by the Science Advisory
Board. In addition, today's proposal
gives flexibility to States by allowing
them to award different levels of
Cryptospondium treatment credit to
their systems based on site-specific
demonstrations.
With respect to the burden the
LT2ESWTR would place on water
systems and States, EPA has, as
described previously in this preamble,
attempted to minimize overall costs
under the proposed LT2ESWTR. This is
achieved through risk-targeting of
additional treatment requirements,
allowing most small systems to avoid
Cryptospondium monitoring costs
through E. coli screening, and
facilitating the use of lower cost
treatment technologies like UV.
In summary, EPA has concluded that
the proposed option for the LT2ESWTR
is needed to provide a significant public
health benefit by reducing exposure to
Cryptospondium. While many public
water systems achieve adequate control
of Cryptospondium, additional
treatment should be required for filtered
systems with elevated source water
pathogen levels and for unfiltered
systems. The availability of improved
analytical methods allows additional
treatment requirements to be targeted to
higher risk systems, and the
development of technologies like UV
makes it feasible for systems to provide
additional treatment. The monetized
benefits of today's proposal significantly
exceed total costs, and EPA believes
there will be substantial unquantified
benefits as well.
f. Regulatory alternatives considered.
As required under section 205 of
UMRA, EPA considered several
regulatory alternatives to address
systems at risk for contamination by
microbial pathogens, specifically
including Cryptospondium. A detailed
discussion of these alternatives can be
found in section VI of the preamble and
also in the Economic Analysis for the
LT2ESWTR (USEPA 2003a).
g. Selection of the hast costly, most
cost-effective, or least burdensome
alternative that achieves the objectives
of the rule. Among the regulatory
alternatives considered for the
LT2ESWTR, as described in section VI,
the Agency believes the proposed
alternative is the most cost-effective that
achieves the objectives of the rule. The
objective of the LT2ESWTR is to reduce
risk from Cryptospondium and other
pathogens in systems where current
regulations do not provide sufficient
protection.
The Agency evaluated a less costly
and less burdensome alternative.
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47765
However, this alternative would provide
no benefit to several thousand
consumers who, under the proposed
alternative, would receive benefits that
most likely exceed their costs, based on
Agency estimates. This is illustrated in
the LT2ESWTR Economic Analysis
(USEPA 2003a). By failing to reduce risk
for consumers where additional
treatment requirements would be cost-
effective, the less costly alternative does
not appear to achieve the objectives of
the LT2ESWTR.
The other alternatives considered by
the Agency achieve the objectives of the
rule, but are more costly, more
burdensome, and potentially less cost-
effective. The proposed alternative
targets additional treatment
requirements to systems with the
highest vulnerability to
Cryptosporidium, and maximizes net
benefits under a broad range of
conditions (USEPA 2003a).
Consequently, the Agency has found the
proposed alternative to be the most cost-
effective among those that achieve the
objectives of the rule.
3. Impacts on Small Governments
EPA has determined that this rule
contains no regulatory requirements that
might significantly or uniquely affect
small governments. Thus, today's rule is
not subject to the requirements of
section 203 of UMRA. As described in
section VII.C, EPA has certified that this
proposed rule will not have a significant
economic impact on a substantial
number of small entities. Estimated
annual expenditures by small systems
for the LT2ESWTR range from $7.9 to
$13.0 million at a 3% discount rate and
$8.0 to $13.0 million at a 7% discount
rate. While the treatment requirements
of the LT2ESWTR apply uniformly to
both small and large public water
systems, large systems bear a majority of
the total costs of compliance with the
rule. This is due to the fact that large
systems treat a majority of the drinking
water that originates from surface water
sources.
E. Executive Order 13132: 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 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 has concluded that this proposed
rule may have federalism implications,
because it may impose substantial direct
compliance costs on State or local
governments, and the Federal
government will not provide the funds
necessary to pay those costs. The
proposed rule may result in
expenditures by State, local, and Tribal
governments, in the aggregate of $100
million or more in any one year. Costs
are estimated to range from $73 to $111
million at a 3 percent discount rate and
$81 to $121 million using a 7 percent
discount rates based on the median
distribution modeled from 1CRSSL and
Information Collection Rule
Cryptosporidium occurrence data sets.
Accordingly, EPA provides the
following federalism summary impact
statement as required by section 6(b) of
Executive Order 13132.
EPA consulted with representatives of
State and local officials early in the
process of developing the proposed
regulation to permit them to have
meaningful and timely input into its
development. Section VII.D.2.e
describes EPA's consultation with
representatives of State and local
officials. This consultation included
State and local government
representatives on the Stage 2 M-DBP
Federal Advisory Committee, the
representatives from small local
governments to the SBAR panel, a
meeting with representatives from
ASDWA, NGA, NCSL, 1CMA, NLC, the
County Executives of America, and
health departments, consultation with
Tribal governments at four meetings,
and comments from State and local
governments on a pre-proposal draft of
the LT2ESWTR.
Representatives of State and local
officials were generally concerned with
ensuring that drinking water regulations
are adequately protective of public
health and that any additional
regulations achieve significant health
benefits in return for required
expenditures. They were specifically
concerned with the burden of the
proposed rule, both in cost and
technical complexity, giving flexibility
to systems and States, balancing the
control of microbial risks and DBF risks,
funding for implementing new
regulations, equal protection for small
systems, and early implementation of
monitoring by large systems.
EPA has concluded that the proposed
LT2ESWTR is needed to reduce the
public health risk associated with
Cryptosporidium in drinking water.
Estimated benefits for the rule are
significantly higher than costs. Further,
as described in this section and in
section VII.D.2.e, the Agency believes
that today's proposal addresses many of
the concerns expressed by
representatives of government officials.
Under the proposed LT2ESWTR,
expenditures for additional treatment
are targeted to the fraction of systems
with the highest vulnerability to
Cryptosporidium, thereby minimizing
burden for the majority of systems that
will not be required to provide
additional treatment. The microbial
toolbox of compliance options will
provide flexibility to systems in meeting
additional treatment requirements, and
States have the flexibility to award
treatment credits based on site-specific
demonstrations, Disinfection profiling
provisions are intended to ensure that
systems do not reduce microbial
protection as they take steps to reduce
exposures to DBFs.
The LT2ESWTR achieves equal public
health protection for smal! systems.
However, the use of E. coli monitoring
by small systems as a screening analysis
to determine the need for
Cryptosporidium monitoring will
reduce monitoring costs for most small
systems. Capital projects related to the
rule would be eligible for funding from
the Drinking Water State Revolving
Fund, which includes specific funding
for small communities. EPA is planning
to support the initial monitoring by
large systems that takes place within the
first 2.5 years after promulgation. This
will substantially reduce the burden on
States associated with early
implementation of monitoring
requirements.
In the spirit of Executive Order 13132,
and consistent with EPA policy to
promote communications between EPA
and State and local governments, EPA
specifically solicits comment on this
proposed rule from State and local
officials.
F. Executive Order 13175: Consultation
and Coordination With Indian Tribal
Governments
Executive Order 13175, entitled
"Consultation and Coordination with
Indian Tribal Governments" (65 FR
67249, November 9, 2000), requires EPA
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47766 Federal Register/Vol. 68. No. 154/Monday. August 11, 2003/Proposed Rules
to develop "an accountable process to
ensure meaningful and timely input by
Tribal officials in the development of
regulatory policies that have Tribal
implications." "Policies that have Tribal
implications" is defined in the
Executive Order to include regulations
that have "substantial direct effects on
one or more Indian tribes, on the
relationship between the Federal
government and the Indian tribes, or on
the distribution of power and
responsibilities between the Federal
government and Indian tribes."
Under Executive Order 13175, EPA
may not issue a regulation that has
Tribal 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 Tribal
governments, or EPA consults with
Tribal officials early in the process of
developing the proposed regulation and
develops a Tribal summary impact
statement.
EPA has concluded that this proposed
rule may have Tribal implications,
because it may impose substantial direct
compliance costs on Tribal
governments, and the Federal
government will not provide the funds
necessary to pay those costs. EPA has
identified 67 Tribal water systems
serving a total population of 78,956 that
may be subject to the LT2ESWTR. They
will bear an estimated total annualized
cost of $135,974 at a 3 percent discount
rate ($138,910 at 7 percent) to
implement this rule as proposed.
Estimated mean annualized cost per
system ranges from $792 to $23,979 at
a 3 percent discount rate ($844 to
$26,194 at 7 percent) depending on
system size (see section 7 of the
LT2ESWTR Economic Analysis (USEPA
2003a) for details). Accordingly, EPA
provides the following Tribal summary
impact statement as required by section
5(b) of Executive Order 13175.
EPA consulted with representatives of
Tribal officials early in the process of
developing this regulation to permit
them to have meaningful and timely
input into its development. Section
VII.D.2.e describes EPA's outreach and
consultation with Tribes, which
included presentations on the
LT2ESWTR at four Tribal conferences
and meetings, mailing fact sheets and
presentation materials regarding the
proposal to Tribes on several occasions,
and a teleconference with
representatives of Tribal officials to
comment on the proposed rule.
As discussed in section VII.D.2.e,
Tribal representatives stated that
protection of public health is important
regardless of the number of people a
system is serving, and they recognized
that the LT2ESWTR would provide a
public health benefit. However, Tribal
representatives were concerned about
the availability of funding to implement
the regulation and asked about the
projected impact on Tribes (e.g., number
of Tribal surface water systems that
would be affected). Also, the Tribal
representative to the Federal Advisory
Committee was concerned that risk
mitigation plans for uncovered finished
water storage facilities account for
cultural uses by Tribes.
EPA has concluded that the proposed
LT2ESWTR is needed to reduce the risk
associated with Cryptosporidium in
public water systems using surface
water sources. Projected benefits for
today's proposal are substantially
greater than costs. Moreover, as
described in this section and in section
VII.D,2.e, today's proposal addresses
many of the concerns stated by Tribal
representatives.
The LT2ESWTR will provide
equivalent public health protection to
all system sizes, including Tribal
systems. By targeting additional
treatment requirements to higher risk
systems, the LT2ESWTR will minimize
overall burden in comparison with
requiring additional treatment by all
systems. In addition, the provision in
the proposal allowing E. coli screening
to determine if Cryptosporidium
monitoring is necessary will reduce
monitoring costs for many small Tribal
systems. (EPA notes that 66 of the 67
Tribal systems identified by the Agency
as subject to the LT2ESWTR are small
systems.) Due to the health risks
associated with Cryptosporidium,
capital expenditures needed for
compliance with the rule will be eligible
for Federal funding sources, specifically
the Drinking Water State Revolving
Fund. EPA is developing guidance that
will address consideration of Tribal
cultural uses of uncovered finished
water storage facilities.
In the spirit of Executive Order 13175,
and consistent with EPA policy to
promote communications between EPA
and Tribal governments, EPA
specifically solicits additional comment
on this proposed rule from Tribal
officials,
G. Executive Order 13045: Protection of
Children from Environmental Health
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 Executive
Order 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.
This proposed rule is subject to the
Executive Order because it is an
economically significant regulatory
action as defined in Executive Order
12866, and we believe that the
environmental health or safety risk
addressed by this action may have a
disproportionate effect on children.
Accordingly, we have evaluated the
environmental health or safety effects of
Cryptosporidium on children. The
results of this evaluation are contained
in Cryptosporidium: Risk for Infants and
Children (USEPA 2001d) and described
in this section of this preamble. Further,
while available information is not
adequate to conduct a quantitative risk
assessment specifically on children,
EPA has assessed the risk associated
with Cryptosporidium in drinking water
for the general population, including
children. This assessment is described
in the Economic Analysis for the
LT2ESWTR (USEPA 2003a) and is
summarized in section VI of this
preamble. Copies of these documents
and supporting information are
available in the public docket for
today's proposal.
Cryptosporidiosis in children is
similar to adult disease (USEPA 2001d).
Diarrhea is the most common symptom.
Other common symptoms in otherwise
healthy (i.e., immunocompetent)
children include anorexia, vomiting,
abdominal pain, fever, dehydration and
weight loss.
The risk of illness and death due to
cryptosporidiosis depends on several
factors, including age, nutrition,
exposure, genetic variability, disease
and the immune status of the
individual. Mortality resulting from
diarrhea generally occurs at a greater
rate among the very young and elderly
(Gerba et al, 1996). During the 1993
Milwaukee drinking water outbreak,
associated mortalities in children were
reported. Also, children with laboratory-
confirmed cryptosporidiosis were more
likely to have an underlying disease that
altered their immune status (Cicirello et
al., 1997). In that study, the observed
association between increasing age of
children and increased numbers of
laboratory-con firmed cryptosporidiosis
suggested to the authors that the data
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47767
are consistent with increased tap water
consumption of older children.
However, due to data limitations, this
observation could not be adequately
analyzed. Asymptomatic infection,
especially in underdeveloped
communities, can have a substantial
effect on childhood growth (Bern et al,
2002).
Cryptosporidiosis appears to be more
prevalent in populations, such as
children, that may not have established
immunity against the disease and may
be in greater contact with
environmentally contaminated surfaces
(DuPont et al, 1995). In the United
States, children aged one to four years
are more likely than adults to have the
disease. The most recent reported data
on cryptosporidiosis shows the
occurrence rate (for the year 1999) is
higher in children ages one to four (3.03
incidence rate per 100,000) than in any
adult age group (CDC, 2001). Evidence
from blood sera antibodies collected
from children during the 1993
Milwaukee outbreak suggest that
children had greater levels of
Cryptosporidium infection than
predicted for the general community
(based on the random-digit dialing
telephone survey method) (McDonald et
al, 2001).
Data indicate a lower incidence of
cryptosporidiosis infection during the
first year of life. This is attributed to
breast-fed infants consuming less tap
water and, hence, having less exposure
to Cryptosporidium, as well as the
possibility that mothers confer short
term immunity to their children. For
example, in a survey of over 30,000
stool sample analyses from different
patients in the United Kingdom, the one
to five 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
six months of age showed a higher rate
of infection than individuals aged less
than six months (Casemore, 1990).
Similarly, in the U.S., of 2,566 reported
Cryptosporidium illnesses in 1999, 525
occurred in ages one to four (incidence
rate of 3.03 per 100,000) compared with
58 cases in infants under one year
(incidence rate of 1.42 per 100,000)
(CDC, 2001).
An infected child may spread the
disease to other children or family
members (Heijbel et al., 1987, Osewe et
a]., 1996). Millard etal (1994)
documented greater household
secondary transmission of
cryptosporidiosis from children than
from adults to household and other
close contacts. Children continued to
shed oocysts for more than two weeks
(mean 16.5 days) after diarrhea
cessation (Tangerman etal, 1991).
While Cryptosporidium may have a
disproportionate effect on children,
available data are not adequate to
distinctly assess the health risk for
children resulting from
Qyptospor;'c/j urn-contaminated drinking
water. In assessing risk to children
when evaluating regulatory alternatives
for the LT2ESWTR, EPA assumed the
same risk for children as for the
population as a whole.
Section VI of this preamble presents
the regulatory alternatives that EPA
evaluated for the proposed LT2ESWTR.
Among the four alternatives the Agency
considered, three involved a risk-
targeting approach in which additional
Cryptosporidium treatment
requirements are based on source water
monitoring results. A fourth alternative
involved additional treatment
requirements for all systems.
The alternative requiring additional
treatment by all systems was not
selected because of concerns about
feasibility and because it imposed costs
but provided few benefits to systems
with high quality source water (i.e.,
relatively low Cryptosporidium risk).
The three risk-targeting alternatives
were evaluated based on several factors,
including costs, benefits, net benefits,
feasibility of implementation, and other
specific impacts (e.g., impacts on small
systems or sensitive subpopulations).
The proposed alternative was
recommended by the M-DBP Federal
Advisory Committee and selected by
EPA as the Preferred Regulatory
Alternative because it was deemed
feasible and provides significant public
health benefits in terms of avoided
illnesses and deaths. EPA's analysis of
benefits and costs indicates that the
proposed alternative ranks highly
among those evaluated with respect to
maximizing net benefits, as shown in
the LT2ESWTR Economic Analysis
(USEPA 2003a). This document is
available in the docket for this action.
The result of the LT2ESWTR will be
a reduction in the risk of illness for the
entire population, including children.
Because available evidence indicates
that children may be more vulnerable to
cryptosporidiosis than the rest of the
population, the LT2ESWTR may,
therefore, result in greater risk reduction
for children than for the 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
Cryp tosporidium.
H. Executive Order 13211: Actions That
Significantly Affect Energy Supply,
Distribution, or Use
This rule is not a "significant energy
action" as defined in Executive Order
13211, "Actions Concerning Regulations
That Significantly Affect Energy Supply,
Distribution, or Use" (66 FR 28355 (May
22, 2001)) because it is not likely to
have a significant adverse effect on the
supply, distribution, or use of energy.
This determination is based on the
following analysis.
The first consideration is whether the
LT2ESWTR would adversely affect the
supply of energy. The LT2ESWTR does
not regulate power generation, either
directly or indirectly. The public and
private utilities that the LT2ESWTR
regulates do not, as a rule, generate
power. Further, the cost increases borne
by customers of water utilities as a
result of the LT2ESWTR are a low
percentage of the total cost of water,
except for a very few small systems that
might install advanced technologies and
then need to spread that cost over a
narrow customer base. Therefore, the
customers that are power generation
utilities are unlikely to face any
significant effects as a result of the
LT2ESWTR. In sum, the LT2ESWTR
does not regulate the supply of energy,
does not generally regulate the utilities
that supply energy, and is unlikely to
affect significantly the customer base of
energy suppliers. Thus, the LT2ESWTR
would not translate into adverse effects
on the supply of energy.
The second consideration is whether
the LT2ESWTR would adversely affect
the distribution of energy. The
LT2ESWTR does not regulate any aspect
of energy distribution. The utilities that
are regulated by the LT2ESWTR already
have electrical service. As derived later
in .this section, the proposed rule is
projected to increase peak electricity
demand at water utilities by only 0.02
percent. Therefore, EPA estimates that
the existing connections are adequate
and that the LT2ESWTR has no
discernable adverse effect on energy
distribution.
The third consideration is whether
the LT2ESWTR would adversely affect
the use of energy. Because some
drinking water utilities are expected to
add treatment technologies that use
electrical power, this potential impact is
evaluated in more detail. The analyses
that underlay the estimation of costs for
the LT2ESWTR are national in scope
and do not identify specific plants or
utilities that may install treatment in
response to the rule. As a result, no
analysis of the effect on specific energy
suppliers is possible with the available
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data. The approach used to estimate the
impact of energy use, therefore, focuses
on national-level impacts. The analysis
estimates the additional energy use due
to the LT2ESWTR, and compares that to
the national levels of power generation
in terms of average and peak loads.
The first step in the analysis is to
estimate the energy used by the
technologies expected to be installed as
a result of the LT2ESWTR. Energy use
is not directly stated in Technologies
and Costs for Control of Microbial
Contaminants and Disinfection By-
products (USEPA 2003c), but the annual
cost of energy for each technology
addition or upgrade necessitated by the
LT2ESWTR is provided. An estimate of
plant-level energy use is derived by
dividing the total energy cost per plant
for a range of flows by an average
national cost of electricity of $0.076/
kWh (USDOE EIA, 2002). These
calculations are shown in detail in
Chapter 7 of the Economic Analysis for
the LT2ESWTR (USEPA 2003a). The
energy use per plant for each flow range
and technology is then multiplied by
the number of plants predicted to install
each technology in a given flow range.
The energy requirements for each flow
range are then added to produce a
national total. No electricity use is
subtracted to account for the
technologies that may be replaced by
new technologies, resulting in a
conservative estimate of the increase in
energy use. Results of the analysis are
shown in Table VII-5 for each of the
modeled Cryptosporidium occurrence
distributions. The results range from an
incremental national annual energy
usage of 0.12 million megawatt-hours
(mW) for the modeled Information
Collection Rule occurrence distribution
to 0.07 million mW for the modeled
ICRSSL occurrence distribution.
TABLE VII-5.—TOTAL INCREASED ANNUAL NATIONAL ENERGY USAGE ATTRIBUTABLE TO THE LT2ESWTR
Technology
CtO2
uv
O3 (0 5 log)
O3 (1 0 log)
Os {2.0 log)
MF/UF
Total
ICR
Plants select-
ing technology
A
77
998
26
24
9
10
1,545
190
2.878
Total annual
energy re-
quired
(kWh/yr)
B
343,297
86,827,218
12,524,670
12,456,132
7,324,561
5,691,144
1,631,873
76,793
126.875.687
ICRSSL
Plants select-
ing technology
C
61
490
19
12
0
8
1,236
17
1.844
Total annual
energy re-
quired
(kWh/yr)
D
268,861
52,212,046
10,328,359
6,119,824
35,259
4,507,577
1,306,067
6,254
74.784.249
ICRSSM
Plants select-
ing technology
E
70
632
21
21
2
5
1,441
52
2.244
Total annual
energy re-
quired
(kWh/yr)
F
312,036
64,515,863
11,467,703
10,759,696
1,787,144
2,790,401
1,522,243
19,686
93.174.772
Source; The LT2ESWTR Economic Analysis {USEPA 2003a).
To determine if the additional energy
required for systems to comply with the
rule would have a significant adverse
effect on the use of energy, the numbers
in Table VII-5 are compared to the
national production figures for
electricity. According to the U.S.
Department of Energy's Information
Administration, electricity producers
generated 3,800 million mW of
electricity in 2001 {USDOE EIA, 2002).
Therefore, even using the highest
assumed energy use for the LT2ESWTR,
the rule when fully implemented would
result in only a 0.003 percent increase
in annual average energy use.
In addition to average energy use, the
impact at times of peak power demand
is important. To examine whether
increased energy usage might
significantly affect the capacity margins
of energy suppliers, their peak season
generating capacity reserve was
compared to an estimate of peak
incremental power demand by water
utilities.
Both energy use and water use are
highest in the summer months, so the
most significant effects on supply would
be seen then. In the summer of 2001,
U.S. generation capacity exceeded
consumption by 15 percent, or
approximately 120,000 mW (USDOE
EIA 2002). Assuming around-the-clock
operation of water treatment plants, the
total energy requirement can be divided
by 8,760 hours per year to obtain an
average power demand of 15 mW for the
modeled Information Collection Rule
occurrence distribution. A more
detailed derivation of this value is
shown in Appendix P of the Economic
Analysis for the LT2ESWTR (USEPA
2003a). Assuming that power demand is
proportional to water flow through the
plant, and that peak flow can be as high
as twice the average daily flow during
the summer months, about 30 mW
could be needed for treatment
technologies installed to comply with
the LT2ESWTR. This is only 0.024
percent of the capacity margin available
at peak use.
Although EPA recognizes that not all
areas have a 15 percent capacity margin
and that this margin varies across
regions and through time, this analysis
reflects the effect of the rule on national
energy supply, distribution, or use.
While certain areas, notably California,
have experienced shortfalls in
generating capacity in the recent past, a
peak incremental power requirement of
30 mW nationwide is not likely to
significantly change the energy supply,
distribution, or use in any given area.
Considering this analysis, EPA has
concluded that LT2ESWTR is not likely
to have a significant adverse effect on
the supply, distribution, or use of
energy.
/. National Technology Transfer and
Advancement Act
Section 12(d) of the National
Technology Transfer and Advancement
Act (NTTAA) of 1995, Public Law 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.,
material specifications, test methods,
sampling procedures, and business
practices) that are developed or adopted
by voluntary consensus standard bodies.
The NTTAA directs EPA to provide
Congress, through OMB, explanations
when the Agency decides not to use
available and applicable voluntary
consensus standards.
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The proposed rulemaking involves
technical standards. EPA proposes to
use several voluntary consensus
standards (VCS) methods for
enumerating E. coli in surface waters.
These methods are listed in section
IV.K.2, Table IV-37, and were
developed or adopted by the following
organizations: American Public Health
Association in Standard Methods for the
Examination of Water and Wastewater,
20th, 19th, and 18th Editions, the
American Society of Testing Materials
in Annual Book of ASTM Standards—
Water and Environmental Technology,
and the Association of Analytical
Chemists in Official Methods of
Analysis of AOAC International, 16th
Edition. These methods are available in
the docket for today's proposal. EPA has
concluded that these methods have the
necessary sensitivity and specificity to
meet the data quality objectives of the
LT2ESWTR.
The Agency conducted a search to
identify potentially applicable voluntary
consensus standards for analysis of
Cryptosporidium. However, we
identified no such standards. Therefore,
EPA proposes to use the following
methods for Cryptosporidium analysis:
Method 1622: "Cryptosporidium in
Water by Filtration/IMS/FA" (EPA-821-
R-01-026, April 2001) (USEPA 2001e)
and Method 1623: "Cryptosporidium
and Giardia in Water by Filtration/IMS/
FA" (EPA 821-R-01-025, April 2001)
(USEPA 2001f).
EPA welcomes comments on this
aspect of the proposed rulemaking and,
specifically, invites the public to
identify additional potentially
applicable voluntary consensus
standards, and to explain why such
standards should be used in this
regulation.
/. Executive Order 12898: Federal
Actions To Address Environmental
Justice in Minority Populations or Low-
Income Populations
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.
Two aspects of the LT2ESWTR
comply with the order that requires the
Agency to consider environmental
justice issues in the rulemaking and to
consult with stakeholders representing a
variety of economic and ethnic
backgrounds. These are: (1) The overall
nature of the rule, and (2) the convening
of a stakeholder meeting specifically to
address environmental justice issues.
The Agency built on the efforts
conducted during the development of
the IESWTR to comply with Executive
Order 12898. On March 12,1998, the
Agency held a stakeholder meeting to
address various components of pending
drinking water regulations and how
they might impact sensitive
subpopulations, minority populations,
and low-income populations. This
meeting was a continuation of
stakeholder meetings that started in
1995 to obtain input on the Agency's
Drinking Water Programs. Topics
discussed included treatment
techniques, costs and benefits, data
quality, health effects, and the
regulatory process. Participants were
national, State, Tribal, municipal, and
individual stakeholders. EPA conducted
the meeting by video conference call
between eleven cities. The major
objectives for the March 12,1998,
meeting were the following:
• Solicit ideas from stakeholders on
known issues concerning current
drinking water regulatory efforts;
• Identify key areas of concern to
stakeholders; and
• Receive suggestions from
stakeholders concerning ways to
increase representation of communities
in OGWDW regulatory efforts.
In addition, EPA developed a plain-
English guide for this meeting to assist
stakeholders in understanding the
multiple and sometimes complex issues
surrounding drinking water regulations.
The LT2ESWTR and other drinking
water regulations promulgated or under
development are expected to have a
positive effect on human health
regardless of the social or economic
status of a specific population. The
LT2ESWTR serves to provide a similar
level of drinking water protection to all
groups. Where water systems have high
Cryptosporidium levels, they must treat
their water to achieve a specified level
of protection. Further, to the extent that
levels of Cryptosporidium in drinking •
water might be disproportionately high
among minority or low-income
populations (which is unknown), the
LT2ESWTR will work to remove those
differences. Thus, the LT2ESWTR meets
the intent of Federal policy requiring
incorporation of environmental justice
into Federal agency missions.
The LT2ESWTR applies uniformly to
CWSs, NTNCWSs, and TNCWSs that
use surface water or GWUDI as their
source. Consequently, this rule provides
health protection from pathogen
exposure equally to all income and
minority groups served by surface water
and GWUDI systems.
K. Consultations with the Science
Advisory Board, National Drinking
Water Advisory Council, and the
Secretary of Health and Human Services
In accordance with sections 1412 (d)
and (e) of SDWA, the Agency has
consulted with the Science Advisory
Board (SAB), theNational Drinking
Water Advisory Council (NDWAC), and
will consult with the Secretary of Health
and Human Services regarding the
proposed LT2ESWTR during the public
comment period. EPA charged the SAB
panel with reviewing the following
aspects of the LT2ESWTR proposal:
• The analysis of Cryptosporidium
occurrence, as described in Occurrence
and Exposure Assessment for the
LT2ESWTR (USEPA 2003b);
• The pre- and post-LT2ESWTR
Cryptosporidium risk assessment, as
described in Economic Analysis for the
LT2ESWTR (USEPA 2003a); and
• The treatment credits for the
following four microbial toolbox
components: raw water off-stream
storage, pre-sedimentation, lime
softening, and lower finished water
turbidity (described in section IV.C of
this preamble).
EPA met with the SAB to discuss the
LT2ESWTR on June 13, 2001
(Washington, DC), September 25-26,
2001 (teleconference), and December
10-12, 2001 (Los Angeles, CA). Written
comments from the December 2001
meeting of the SAB addressing the
occurrence analysis and risk assessment
were generally supportive. EPA has
responded to the SAB's
recommendations for Cryptosporidium
occurrence analysis in the current draft
of Occurrence and Exposure Assessment
for the LT2ESWTR (USEPA 2003b), and
EPA has addressed the SAB's comments
on risk assessment in the current draft
of Economic Analysis for the
LT2ESWTR (USEPA 2003a). Comments
from the SAB on the microbial toolbox
components and the Agency's responses
to those comments are described in
section IV.C of this preamble.
EPA met with the NDWAC on
November 8, 2001, in Washington, DC,
to discuss the LT2ESWTR proposal.
EPA specifically requested comments
from the NDWAC on the regulatory
approach taken in the proposed
microbial toolbox (e.g., proposal of
specific design and implementation
criteria for treatment credits). The
Council was generally supportive of
EPA establishing criteria for awarding
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treatment credit to toolbox components,
but recommended that EPA provide
flexibility for States to address system
specific situations. EPA believes that the
demonstration of performance credit,
described in section IV.C.17, provides
this flexibility by allowing States to
award higher or lower levels of
treatment credit for microbial toolbox
components based on site specific
conditions. Minutes of the NDWAC and
SAB meetings are in the docket for
today's proposal.
L. Plain Language
Executive Order 12866 encourages
Federal agencies to write rules in plain
language. EPA invites comments on
how to make this proposed rule easier
to understand. For example: Has EPA
organized the material to suit
commenters' 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 ordering
of sections, use of headings, paragraphs)
make the rule easier to understand?
Could EPA improve clarity by adding
tables, lists, or diagrams? What else
could EPA do to make the rule easier to
understand?
VIII. References
Aboytes R., F.A. Abrams, W.E. McElroy, C.
Rheinecker, G.D. DiGiovanni, R. Seeny, M.
LeChevallier, and R. Kozik. 2002.
Continuous monitoring for detection of
infectious Cryptosporidium parvum
oocysts in drinking water. Abstracts of the
102nd General Meeting of the American
Society for Microbiology, Salt Lake City,
UT, May 19-22.
Adham, S., J. Jacangelo, and J. Laine. 1995.
Low pressure membranes; assessing
integrity. J. AWWA. 03:3:62.
Adham, S., P. Gagliado, D. Smith, D. Ross, K.
Gramith, and R. Trussell. 1998. Monitoring
of reverse osmosis for virus rejection.
Proceedings of the Water Quality
Technology Conference of the American
Waterworks Association, Denver, CO.
APHA. 1992. Standard Methods for the
Examination of Water and Wastewater;
18th Edition. American Public Health
Association, Washington B.C.
Arora, H., M. LeChevallier, R. Aboytes, E.
Bouwer, C. O'Melia, W. Ball, W. Weiss,
and T. Speth. 2000. Full-scale evaluation of
riverbank filtration at three Midwest water
treatment plants. Proceedings of the Water
Quality Technology Conference, Salt Lake
City, Utah, American Water Works
Association, Denver, Colorado.
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-------
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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: July 11, 2003.
Linda J. Fisher,
Acting 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
1. 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-1,
300J-9, and300j-ll.
2. Section 141.2 is amended by
adding, in alphabetical order,
definitions for Bag filters, Bank
filtration, Cartridge filters, Flowing
stream, Lake/reservoir, Membrane
filtration, Off-stream raw water storage,
Plant intake, Presedimentation, and
Two-stage lime softening to read as
follows:
§141.2 Definitions.
*****
Bag filters are pressure-driven
separation devices that remove
particulate matter larger than 1 |im
using an engineered porous filtration
media through either surface or depth
filtration. Bag filters are typically
constructed of a non-rigid, fabric
filtration media housed in a pressure
vessel in which the direction of flow is
from the inside of the bag to outside.
Bank filtration is a water treatment
process that uses a pumping well to
recover surface water that has naturally
infiltrated into ground water through a
river bed or bank(s). Infiltration is
typically enhanced by the hydraulic
gradient imposed by a nearby pumping
water supply or other well(s).
*****
Cartridge filters are pressure-driven
separation devices that remove
particulate matter larger than 1 um
using an engineered porous filtration
media through either surface or depth
filtration. Cartridge filters are typically
constructed as rigid or semi-rigid, self-
supporting filter elements housed in
pressure vessels in which flow is from
the outside of the cartridge to the inside.
*****
Flowing stream is a course of running
water flowing in a definite channel.
Lake/reservoir refers to a natural or
man made basin or hollow on the
Earth's surface in which water collects
or is stored that may or may not have
a current or single direction of flow.
* * * * *
Membrane filtration is a pressure-
driven or vacuum-driven separation
process in which particulate matter
larger than 1 um is rejected by an
engineered barrier primarily through a
size exclusion mechanism, and which
has a measurable removal efficiency of
a target organism that can be verified
through the application of a direct
integrity test. This definition includes
the common membrane technologies of
microfiltration (MF), ultrafiltration (UF),
nanofiltration (NF), and reverse osmosis
ERO).
*****
Off-stream raw water storage refers to
an impoundment in which water is
stored prior to treatment and from
which outflow is controlled.
*****
Plant intake refers to the works or
structures at the head of a conduit
through which water is diverted from a
source (e.g., river or lake) into the
treatment plant.
*****
Presedimentation is a preliminary
unit process used to remove gravel, sand
and other particulate material from the
source water through settling before it
enters the main treatment plant.
*****
Two-stage lime softening refers to a
process for the removal of hardness by
the addition of lime and consisting of
two distinct unit clarification processes
in series prior to filtration.
*****
3. Appendix A to Subpart Q of part
141 is amended in section I, Part A by
adding entry number 10:
Subpart Q—Public Notification of
Drinking Water Violations.
APPENDIX A TO SUBPART Q OF PART 141—NPDWR VIOLATIONS AND OTHER SITUATIONS REQUIRING PUBLIC NOTICE
MCL/MRDL/TT violations2
Monitoring and testing procedure violations
Contaminant
Tier of public
notice required
Citation
Tier of public
notice required
Citation
of National Primary
Water Regulations
I. Violations
Drinking
(NPDWR)3.
A. Microbiological Contaminants
-------
47776 Federal Register/Vol. 68, No. 154/Monday, August 11, 2003/Proposed Rules
APPENDIX A TO SUBPART Q OF PART 141-NPDWR VIOLATIONS AND OTHER SITUATIONS REQUIRING PUBLIC NOTICE '-
MCL/MRDL/TT violations'
Contaminant
10. LT2ESWTR violations
Tier of public
notice required
Citation
2 141.720-141.729
Monitoring and testing procedure violations
Tier of public
notice required
Citation
3 141.701-141.707;
141.713; 141.730
141.711-
.Violations and other stations no, Hsted in ,hs
°f
technique, monitoring, and testing procedure requirements.
4. Part 141 is amended by adding a
new subpart W to read as follows:
SubpartW—Enhanced Filtration and
Disinfection for Cryptoaporidium
General Requirements
141.700 Applicability.
141.701 General requirements.
Source Water Monitoring Requirements
141.702 Source water monitoring.
141.703 Sampling schedules.
141.704 Sampling locations.
141.705 Analytical methods.
141.706 Requirements for use of an
approved laboratory.
141.707 Reporting source water monitoring
results.
141.708 Previously collected data.
141.709 Bin classification for filtered
systems.
Disinfection Profiling and Benchmarking
Requirements
141.710 [Reserved]
141.711 Determination of systems required
to profile.
141.712 Schedule for disinfection profiling
requirements.
141.713 Developing a profile.
141.714 Requirements when making a
significant change in disinfection
practice.
Treatment Technique Requirements
141.720 Treatment requirements for filtered
systems.
141.721 Treatment requirements for
unfiltered systems.
141.722 Microbial toolbox options for
meeting Cryptoaporidium treatment
requirements.
141.723 [Reserved]
141.724 Requirements for uncovered
finished water storage facilities.
Requirements for Microbial Toolbox
Components
141.725 Source toolbox components,
141.726 Pre-filtration treatment toolbox
components.
141.727 Treatment performance toolbox
components.
141.728 Additional filtration toolbox
components.
141.729 Inactivation toolbox components.
Reporting and Recordkeeping Requirements
141.730 Reporting requirements.
141.731 Recordkeeping requirements.
Subpart W—Enhanced Filtration and
Disinfection for Cryptosporidium
General Requirements
§ 141.700 Applicability.
The requirements of this subpart
apply to all subpart H systems. Failure
to comply with any requirement of this
subpart is a violation and requires
public notification.
§141.701 General requirements.
(a) All subpart H systems, including
wholesale systems, must characterize
their source water to determine what (if
any) additional treatment is necessary
for Cryptosporidium, unless they meet
the criteria in either paragraph (f) or (g)
of this section.
(b] Systems serving at least 10,000
people that currently provide filtration
or that are unfiltered and required to
install filtration must conduct source
water monitoring that includes
Cryptosporidium, E. coh, and turbidity
sampling and comply with the
treatment requirements in § 141.720.
(c) Systems serving fewer than 10,000
people that currently provide filtration
or that are unfiltered and required to
install filtration must conduct source
water monitoring consisting of E. coli
sampling or sampling of an alternative
indicator approved by the State. If the
annual mean concentration of E, coli
exceeds the levels specified in
§141.702(b),orifthelevel of a State-
approved alternate indicator exceeds a
State-approved alternative indicator
trigger level, systems must conduct
Cryptosporidium monitoring to
complete the source water monitoring
requirements and comply with the
treatment requirements in § 141.720.
(d) Systems that are unfiltered and
meet all the filtration avoidance criteria
of § 141.71 must conduct source water
monitoring consisting of
Cryptosporidium sampling and comply
with the treatment requirements in
§141.721.
(e) Systems must comply with the
requirements in this subpart based on
the schedule in the following table,
except that systems are not required to
conduct source water monitoring if they
meet the criteria in paragraph (f) of this
section for systems that currently
provide filtration or that are unfiltered
and required to install filtration or
paragraph (g) of this section for systems
that are unfiltered and meet all the
filtration avoidance criteria of §141.71:
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Federal Register/Vol. 68, No. 154/Monday, August 11, 2003/Proposed Rules
47777
COMPLIANCE REQUIREMENTS TABLE
Systems that are
Must perform . . ,a'b
And comply by
(1) Subpart H systems serving
>10,000 people that currently
provide filtration or that are
unfiltered and required to install
filtration.
(2) Subpart H systems serving
>10,000 people that are
unfiltered and meet the filtration
avoidance criteria of § 141.71.
(3) Subpart H systems serving
<10,000 people that currently
provide filtration or that are
unfiltered and required to install
filtration and are not required to
monitor for Cryptosporidium
based on E. coli or other indi-
cator monitoring results'3.
(4) Subpart H systems serving
<10,000 people that currently
provide filtration or that are
unfiltered and required to install
filtration and must perform
Cryptosporidium monitoring
based on E. coli or other indi-
cator monitoring results d.
(5) Subpart H systems serving
<10,000 people that are
unfiltered and meet the filtration
avoidance criteria of § 141.71.
(i) 24 months of source water monitoring for
Cryptosporidium, E. coli and turbidity at least
once each month beginning no later than [Date 6
Months After Date of Publication of Final Rule in
the Federal Register].
(ii) Treatment technique implementation, if nec-
essary.
(i) 24 months of source water monitoring for
Cryptosporidium at least once each month begin-
ning no later than [Date 6 Months After Date of
Publication of Final Rule in the Federal Register].
(ii) Treatment technique implementation, if nec-
essary.
12 months of source water monitoring for E. coli at
least once every two weeks beginning no later
than [Date 30 Months After Date of Publication of
Final Rule in the Federal Register].
(i) 12 months of source water monitoring for 5. coli
at least once every two weeks beginning no later
than [Date 30 Months After Date of Publication of
Final Rule in the Federal Register] and 12
months of source water monitoring for
Cryptosporidium at least twice each month begin-
ning no later than [Date 48 Months After Date of
Publication of Final Rule in the Federal Register].
(ii) Treatment technique implementation, if nec-
essary.
(i) 12 months of source water monitoring for
Cryptosporidium at least twice each month begin-
ning no later than [Date 48 Months After Date of
Publication of Final Rule in the Federal Register}.
ii) Treatment technique implementation, if nec-
essary.
Submitting a monthly report to EPA no later than
ten days after the end of the first month following
the month when the sample is taken.
Installing treatment and complying with the treat-
ment technique no later than [Date 72 Months
After Date of Publication of Final Rule in the Fed-
eral Register]0.
Submitting a monthly report to EPA no later than
ten days after the end of the first month following
the month when the sample is taken.
Installing treatment and complying with the treat-
ment technique no later than [Date 72 Months
After Date of Publication of Final rule in the Fed-
eral Register]c.
Submitting a monthly report to the State no later
than ten days after the end of the first month fol-
lowing the month when the sample is taken.
Submitting a monthly report to the State no later
than ten days after the end of the first month fol-
lowing the month when the sample is taken.
Installing treatment and complying with the treat-
ment technique no later than [Date 102 Months
After Date of Publication of Final Rule in the Fed-
eral Register]c.
Submitting a monthly report to the State no later
than ten days after the end of the first month fol-
lowing the month when the sample is taken.
Installing treatment and complying with the treat-
ment technique no later than [Date 102 Months
After Date of Publication of Final Rule in the Fed-
eral Register]0.
aAny sampling performed more frequently than required must be evenly distributed over the sampling period.
bSystems may use data that meet the requirements in §141.708 collected prior to the monitoring start date to substitute for an equivalent
number of months at the end of the monitoring period.
c States may allow up to an additional two years for complying with the treatment technique requirement for systems making capital improve-
ments.
dSee §141.702(b) to determine if Cryptosporidium monitoring is required.
(f) Systems that currently provide
filtration or that are unfiltered and
required to install filtration are not
required to conduct source water
monitoring under this subpart if the
system currently provides or will
provide a total of at least 5.5 log of
treatment for Cryptosporidium,
equivalent to meeting the treatment
requirements of Bin 4 in §141.720.
Systems must notify the State not later
than the date the system is otherwise
required to submit a sampling schedule
for monitoring under § 141.703 and
must install and operate technologies to
provide a total of at least 5.5 log of
treatment for Cryptosporidium by the
applicable date in paragraph (e) of this
section.
(g) Systems that are unfiltered and
meet all the filtration avoidance criteria
of § 141.71 are not required to conduct
source water monitoring under this
subpart if the system currently provides
or will provide a total of at least 3 log
Cryptosporidium inactivation,
equivalent to meeting the treatment
requirements for unfiltered systems
with a mean Cryptosporidium
concentration of greater than 0.01
oocysts/L in § 141.721. Systems must
notify the State not later than the date
the system is otherwise required to
submit a sampling schedule for
monitoring under § 141.703. Systems
must install and operate technologies to
provide a total of at least 3 log
Cryptosporidium inactivation by the
applicable date in paragraph (e) of this
section.
(h) Systems must comply with the
uncovered finished water storage
facility requirements in § 141.724 no
later than [Date 36 Months After Date of
Publication of Final Rule in the Federal
Register].
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154/Monday, August 11, 2003/Proposed Rules
Source Water Monitoring Requirements
§141.702 Source water monitoring.
(a) Systems must conduct initial
source water monitoring as specified in
§ 141.701(b) through (f).
(b) Systems serving fewer than 10,000
people that provide filtration or that are
unfiltered and required to install
filtration must perform Cryptosporidium
monitoring in accordance with
§ 141.701(e) if they meet any of the
criteria in paragraphs (b)(l) through (4)
of this section.
(1) For systems using lake/reservoir
sources, an annual mean £", coli
concentration greater than 10 E. coli/WO
mL, based on monitoring conducted
under this section, unless the State
approves an alternative indicator trigger.
(2) For systems using flowing stream
sources, an annual mean E. coli
concentration greater than 50 E. coli/lOO
mL, based on monitoring conducted
under this section, unless the Stale
approves an alternative indicator trigger.
(3) If the State approves an alternative
to the indicator trigger in paragraph
(b)(l) or (b)(2) of this section, an annual
concentration that exceeds a State-
approved trigger level, including an
alternative E. coli level, based on
monitoring conducted under this
section,
(4) The system does not conduct b.
coli or other State-approved indicator
monitoring as specified in § 141,701(e).
(c) Systems may submit
Cryptosporidium data collected prior to
the monitoring start date to meet the
initial source water monitoring
requirements of paragraphs (a) through
(b) of this section. Systems may also use
Cryptosporidium data collected prior to
the monitoring start date to substitute
for an equivalent number of months at
the end of the monitoring period. All
data submitted under this paragraph
must meet the requirements in
§141.708.
(d) Systems must conduct a second
round of source water monitoring in
accordance with the requirements in
§ 141.701(b) through (e) of this section,
beginning no later than the dates
specified in paragraphs (d)(l) through
(3) of this section, unless they meet the
criteria in either paragraph § 141.701(f)
or (e).
(1) Systems that serve at least 10,000
people must begin a second round of
source water monitoring no later than
[Date 108 Months After Date of
Publication of Final Rule in the Federal
Register).
(2) Systems serving fewer than 10,000
people that provide filtration or that are
unfiltered and required to install
filtration must begin a second round of
source water monitoring no later than
[Date 138 Months After Date of
Publication of Final Rule in the Federal
Register] and, if required to monitor for
Cryptosporidium under paragraph (b) of
this section, must begin
Cryptosporidium monitoring no later
than [Date 156 Months After Date of
Publication of Final Rule in the Federal
Register].
(3) Systems serving fewer than 10,000
people that are unfiltered and meet the
filtration avoidance requirements of
§ 141.71 must begin a second round of
source water monitoring no later than
[Date 156 Months After Date of
Publication of Final Rule in the Federal
Register].
§ 141.703 Sampling schedules.
(a) Systems required to sample under
§ § 141.701 through 141.702 must
submit a sampling schedule that
specifies the calendar dates that all
required samples will be taken.
(1) Systems serving at least 10,000
people must submit their sampling
schedule for initial source water
monitoring to EPA electronically at
[insert Internet address] no later than
[Date 3 Months After Date of Publication
of Final Rule in tbe Federal Register].
(2) Systems serving fewer than 10,000
people that are filtered or that are
unfiltered and required to install
filtration must submit a sampling
schedule for initial source water
monitoring of E. coli or an alternative
State-approved indicator to the State no
later than [Date 27 Months After Date of
Publication of Final Rule in the Federal
Register].
(3} Filtered systems serving fewer
than 10,000 people that are required to
conduct Cryptosporidium monitoring
and unfiltered systems serving fewer
than 10,000 people must submit a
sampling schedule for initial source
water Cryptosporidium monitoring to
the State no later than [Date 45 Months
After Date of Publication of Final Rule
in the Federal Register].
(4) Systems must submit a sampling
schedule for the second round of source
water monitoring to the State no later
than 3 months prior to the date the
system is required to begin the second
round of monitoring under § 141.702(d).
(b) Systems must collect samples
within two days of the dates indicated
in theiT sampling schedule.
(c) Jf extreme conditions or situations
exist that may pose danger to the sample
collector, or which are unforeseen or
cannot be avoided and which cause the
system to be unable to sample in the
required time frame, the system must
sample as close to the required date as
feasible and submit an explanation for
the alternative sampling date with the
analytical results.
(dj Systems that are unable to report
a valid Cryptosporidium analytical
result for a scheduled sampling date due
to failure to comply with the analytical
method requirements, including the
quality control requirements in
§ 141.705, must collect a replacement
sample within 14 days of being notified
by the laboratory or the State that a
result cannot be reported for that date
and must submit an explanation for the
replacement sample with the analytical
results.
§141.704 Sampling locations.
(a) Unless specified otherwise in this
section, systems required to sample
under §§ 141.701 through 141.702 must
collect source water samples from the
plant intake prior to any treatment.
Where treatment is applied in an intake
pipe such that sampling in the pipe
prior to treatment is not feasible,
systems must collect samples as close to
the intake as is feasible, at a similar
depth and distance from shore.
(b) Presedimentation. Systems using a
presedimentation basin must collect
source water samples after the
presedimentation basin but before any
other treatment. Use of
presedimentation basins during
monitoring must be consistent with
routine operational practice and the
State may place reporting requirements
to verify operational practices. Systems
collecting samples after a
presedimentation basin may not receive
credit for the presedimentation basin
under § 141.726(a).
(c) flaw water off-stream storage.
Systems using an off-stream raw water
storage reservoir must collect source
water samples after the off-stream
storage reservoir. Use of off-stream
storage during monitoring must be
consistent with routine operational
practice, and the State may place
reporting requirements to verify
operational practices.
(d) Bank filtration. The required
sampling location for systems using
bank filtration differs depending on
whether the bank filtered water is
treated by subsequent filtration for
compliance with § 141.173(b) or
§ 141.552(a), as applicable.
(1) Systems using bank filtered water
that is treated by subsequent filtration
for compliance with § 141.173(b) or
§ 141.552(a), as applicable, must collect
source water samples from the well (i.e.,
after bank filtration), but before any
other treatment. Use of bank filtration
during monitoring must be consistent
with routine operational practice and
the State may place reporting
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47779
requirements to verify operational
practices. Systems collecting samples
after a bank fihration process may not
receive credit for the bank filtration
under §141.726(c).
(2) Systems using bank filtration as an
alternative filtration demonstration to
meet their Cryptosporidium removal
requirements under §141.173(b) or
§ 141.552(a), as applicable, must collect
source water samples in the surface
water (i.e., prior to bank filtration).
(3) Systems using a ground water
source under the direct influence of
surface water that meet all the criteria
for avoiding filtration in § 141.71 and
that do not provide filtration treatment
must collect source water samples from
the ground water (e.g., the well).
(e) Multiple sources. Systems with
plants that use multiple water sources at
the same time, including multiple
surface water sources and blended
surface water and ground water sources,
must collect samples as specified in
paragraph (e)(l) or (2) of this section.
The use of multiple sources during
monitoring must be consistent with
routine operational practice and the
State may place reporting requirements
to verify operational practices.
(1) If a sampling tap is available
where the sources are combined prior to
treatment, the sample must be collected
from the tap.
(2) If there is not a sampling tap
where the sources are combined prior to
treatment, systems must collect samples
at each source near the intake on the
same day and must follow either
paragraph (e)(2)(i) or (e)(2)(ii) of this
section for sample analysis.
(i) Composite samples from each
source into one sample prior to analysis.
In the composite, the volume of sample
from each source must be weighted
according to the proportion of the
source in the total plant flow at the time
the sample is collected.
(ii) Analyze samples from each source
separately as specified in § 141.705, and
calculate a weighted average of the
analysis results for each sampling date.
The weighted average must be
calculated by multiplying the analysis
result for each source by the fraction the
source contributed to total plant flow at
the time the sample was collected, and
then summing these values.
§141.705 Analytical methods.
(a) Cryptosporidium. Systems must
use Method 1622 Cryptosporidium in
Water by Filtration/IMS/FA, EPA 821-
R-01-026, April 2001, or Method 1623
Cryptosporidium and Giardia in Water
by Filtration/IMS/FA, EPA 821-R-01-
025, April 2001, for Cryptosporidium
analysis.
(1) Systems are required to analyze at
least a 10 L sample or a packed pellet
volume of at least 2 mL as generated by
the methods listed in paragraph (a) of
this section. Systems unable to process
a 10 L sample must analyze as much
sample volume as can be filtered by two
filters approved by EPA for the .methods
listed in paragraph (a) of this section, up
to a packed pellet volume of 2 mL.
(2)(i) Matrix spikes (MS) samples as
required by the methods in paragraph
(a) of this section must be spiked and
filtered by a laboratory approved for
Cryptosporidium analysis under
§ 141.706. The volume of the MS sample
must be within 10 percent of the volume
of the unspiked sample that is collected
at the same time, and the samples must
be collected by splitting the sample
stream or collecting the samples
sequentially. The MS sample and the
associated unspiked sample must be
analyzed by the same procedure.
METHODS FOR £ coli ENUMERATION 1
(ii) If the volume of the MS sample is
greater than 10 L, the system is
permitted to filter all but 10 L of the MS
sample in the field, and ship the filtered
sample and the remaining 10 L of source
water to the laboratory. In this case, the
laboratory must spike the remaining 10
L of water and filter it through the filter
used to collect the balance of the sample
in the field.
(3) Each sample batch must meet the
quality control criteria for the methods
listed in paragraph (a) of this section.
Flow cytometer-counted spiking
suspensions must be used for MS
samples and ongoing precision and
recovery (OPR) samples; recovery for
OPR samples must be 11% to 100%; for
each method blank, oocysts must not be
detected.
(4) Total Cryptosporidium oocysts as
detected by fluorescein isothiocyanate
(FITC) must be reported as determined
by the color (apple green or alternative
stain color approved under § 141.706(a)
for the laboratory), size (4-6 um) and
shape (round to oval). This total
includes all of the oocysts identified,
less any atypical organisms identified
by FITC, differential interference
contrast (DIG) or 4',6-diamindino-2-
phenylindole (DAPI), including those
possessing spikes, stalks, appendages,
pores, one or two large nuclei filling the
cell, red fluorescing chloroplasts,
crystals, and spores.
(b) E. coli. Systems must use the
following methods listed in this
paragraph for enumeration of E. coli in
source water (table will be replaced
with CFR cite from Guidelines
Establishing Test Procedures for the
Analysis of Pollutants; Analytical
Methods for Biological Pollutants in
Ambient Water when finalized—
expected 2003):
Technique
Most Probable Number (MPN)
Method 1
m-ColiB!ue24 broth
EPA
1103.1
Modified 1103.1
EPA-600-R-013
VCSB methods
Standard meth-
ods
9221B.1/9221F
9223B
9223B
9222D/9222G
9222B/9222G
921 3D
ASTM
D5392-93
AOAC
991.15
Tests must be conducted in a format that provides organism enumeration.
(1) The time from sample collection to
initiation of analysis may not exceed 24
hours. Systems must maintain samples
between 0°C and 10°C during transit.
(2) [Reserved]
(c) Turbidity. Systems must use
methods for turbidity measurement
approved in § 141.74.
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Federal Register/Vol. 68, No. 154/Monday, August 11, 2003/Proposed Rules
§ 141.706 Requirements for use of an
approved laboratory.
(a) Cryptosporidium. Systems must
have Cryptosporidium samples analyzed
by a laboratory that has passed a quality
assurance evaluation under EPA's
Laboratory Quality Assurance
Evaluation Program for Analysis of
Cryptosporidium in Water or a
laboratory that has been certified for
Cryptosporidium analysis by an
equivalent State laboratory certification
program.
(b) E. coli. Any laboratory certified by
the EPA, the National Environmental
Laboratory Accreditation Conference or
the State for total coliform or fecal
coliform analysis in source water under
§ 141.74 is deemed approved for E. coli
analysis under this subpart when the
laboratory uses the same technique for
E. coli that the laboratory uses for source
water in §141.74.
(c) Turbidity. Measurements of
turbidity must be made by a party
approved by the State.
§141.707 Reporting source water
monitoring results.
(a) All systems serving at least 10,000
people must submit the results of all
initial source water monitoring required
under § 141,702(a) to EPA electronically
at [insert Internet address]. Systems that
do not have the ability to submit data
electronically may use an alternative
format approved by EPA.
(b) Systems serving fewer than 10,000
people must submit the results of all
initial source water monitoring required
under § 141.702(a)-(b) to the State.
(c) All systems must submit the
results from the second round of source
water monitoring required under
§ 141.702(d) to the State.
(d) Source water monitoring analysis
results must be submitted not later than
ten days after the end of first month
following the month when the sample is
collected. The submission must include
the applicable information in
paragraphs (e)(l) and (2) of this section.
(e)(l) Systems must report the
following data elements for each
Cryptosporidium analysis:
(i) PWS ID
(ii) Facility ID
(iii) Sample collection point
(iv) Sample collection date
(v) Sample type (field or matrix spike)
(vi) Sample volume filtered (L), to
nearest */> L
(vii) Was 100% of filtered volume
examined
(viii) Number of oocysts counted
(i) For matrix spike samples, systems
must also report the sample volume
spiked and estimated number of oocysts
spiked. These data are not required for
field samples.
(ii) For samples in which less than 10
L is filtered or less than 100% of the
sample volume is examined, systems
must also report the number of filters
used and the packed pellet volume.
(iii) For samples in which less than
100% of sample volume is examined,
systems must also report the volume of
resuspended concentrate and volume of
this resuspension processed through
immunomagnetic separation.
(2) Systems must report the following
data elements for each E, coli analysis:
(i) PWS ID
(ii) Facility ID
(iii) Sample collection point
(iv) Sample collection date
(v) Analytical method number
(vi) Method type
(vii) Source type
(viii)E. co7i/100mL
(ix) Turbidity (Systems serving fewer
than 10,000 people that are not
required to monitor for turbidity
under § 141.701(c) are not required to
report turbidity with their E. coli
results.)
§141.708 Previously collected data.
(a) Systems may comply with the
initial monitoring requirements of
§ 141.702(a) using Cryptosporidium data
collected before the system is required
to begin monitoring if the system meets
the conditions in paragraphs (b) through
(h) of this section and EPA notifies the
system that the data are acceptable.
(b) To be accepted, previously
collected Cryptosporidium data must
meet the conditions in paragraphs (b)(l)
through (5) of this section.
(1) Samples were analyzed by
laboratories using one of the analytical
methods in paragraphs (b)(l)(i) through
(iv) of this section.
(i) Method 1623: Cryptosporidium
and Giardia in Water by Filtration/IMS/
FA, 2001, EPA-821-R-01-025.
(ii) Method 1622: Cryptosporidium in
Water by Filtration/IMS7FA, 2001, EPA-
821-R-01-026.
(iii) Method 1623: Cryptosporidium
and Giardia in Water by Filtration/IMS/
FA, 1999, EPA-821-R-99-006.
(iv) Method 1622: Cryptosporidium in
Water by Filtration/IMS/FA, 1999, EPA-
821-R-99-001.
(2) Samples were collected no less
frequently than each calendar month on
a regular schedule, beginning no earlier
than January 1999.
(3) Samples were collected in equal
intervals of time over the entire
collection period (e.g., weekly,
monthly). Sample collection interval
may vary for the conditions specified in
§ 141.703(c) and (d) if the system
provides documentation of the
condition.
(4) Samples met the conditions for
sampling location specified in
§ 141.704. The system must report the
use of bank filtration, presedimentation,
and raw water off-stream storage during
sampling.
(5) For each sample, the laboratory
analyzed at least 10 L of sample or at
least 2 mL of packed pellet or as much
volume as could be filtered by 2 filters
approved by EPA for the methods listed
in paragraph (b)(l) of this section, up to
a packed pellet volume of 2 mL.
(c) The system must submit a letter to
EPA concurrent with the submission of
previously collected data certifying that
the data meet the conditions in
paragraphs (c)(l) and (2) of this section.
(1) The reported Cryptosporidium
analysis results include all results
generated by the system during the time
period beginning with the first reported
result and ending with the final
reported result. This applies to samples
that were collected from the sampling
location specified for source water
monitoring under this subpart, not
spiked, and analyzed using the
laboratory's routine process for the
analytical methods listed in paragraph
(a)(l) of this section.
(2) The samples were representative
of a plant's source water(s) and the
source water(s) have not changed.
(d) For each sample, the system must
report the data elements in
§141.707(e)(l).
(e) The laboratory or laboratories that
generated the data must submit a letter
to EPA concurrent with the submission
of previously collected data certifying
that the quality control criteria specified
in the methods listed in paragraph (b)(l)
of this section were met for each sample
batch associated with the previously
collected data. Alternatively, the
laboratory may provide bench sheets
and sample examination report forms
for each field, matrix spike, IPR, OPR,
and method blank sample associated
with the previously collected data.
(f) If a system has at least two years
of Cryptosporidium data collected
before [Date of Publication of Final Rule
in the Federal Register] and the system
intends to use these data to comply with
the initial source water monitoring
required under § 141.702(a) in lieu of
conducting new monitoring, the system
must submit to EPA, no later than [Date
2 Months After Date of Publication of
Final Rule in the Federal Register], the
previously collected data and the
supporting information specified in this
section. EPA will notify the system by
[Date 4 Months After Date of Publication
of Final Rule in the Federal Register] as
to whether the data are acceptable. If
EPA does not notify the system that the
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47781
submitted data are acceptable, the
system must carry out initial source
water as specified in §§141.701 through
141.707 until EPA notifies the system
that it has at least two years of
acceptable data.
(g) If a system has fewer than two
years of Cryptosporidium data collected
before [Date of Publication of Final Rule
in the Federal Register] and the system
intends to use these data to meet, in
part, the initial source water monitoring
required under § 141.702(a), the system
must submit to EPA, no later than [Date
8 Months After Date of Publication of
Final Rule in the Federal Register], the
previously collected data and the
supporting information specified in this
section. The system must carry out
initial source water monitoring
according to the requirements in
§§ 141.701 through 141.707 until EPA
notifies the system that it has at least
two years of acceptable data.
(h) If a system has two or more years
of previously collected data and the
system intends to use these data to
comply with the initial source water
monitoring required under § 141.702(a),
but the system also intends to carry out
additional initial source water
monitoring in order to base its
determination of average
Cryptosporidium concentration under
§ 141.709 or § 141.721 on more than two
years of monitoring data, the system
must submit to EPA, no later than [Date
8 Months After Date of Publication of
Final Rule in the Federal Register], the
previously collected data and the
supporting information specified in this
section. The system must carry out
initial source water monitoring
according to the requirements in
§ § 141.701 through 141.707 until EPA
notifies the system that it has at least
two years of acceptable data.
§ 141.709 Bin classification for filtered
systems.
(a) Following completion of the initial
source water monitoring required under
§ 141.702(a), filtered systems and
unfiltered systems that are required to
install filtration must calculate their
initial Cryptosporidium bin
concentration using the
Cryptosporidium results reported under
§ 141.702(a), along with any previously
collected data that satisfy the
requirements of § 141.708, and
following the procedures in paragraphs
(b)(l) through (3) of this section.
(b)(l) For systems that collect a total
of at least 48 samples, the
Cryptosporidium bin concentration is
equal to the arithmetic mean of all
sample concentrations.
(2) For systems that serve at least
10T000 people and collect a total of at
least 24 samples, but not more than 47
samples, the Cryptosporidium bin
concentration is equal to the highest
arithmetic mean of all sample
concentrations in any 12 consecutive
months during which Cryptosporidium
samples were collected.
(3) For systems that serve fewer than
10,000 people and take at least 24
samples, the Cryptosporidium bin
concentration is equal to the arithmetic
mean of all sample concentrations.
(c) Filtered systems and unfiltered
systems that are required to install
filtration must determine their initial
bin classification from the following
table and using the Cryptosporidium bin
concentration calculated under
paragraph (a) of this section:
BIN CLASSIFICATION TABLE FOR FILTERED SYSTEMS
For systems that are:
With a Cryptosporidium bin concentration of. . .1
The bin
classifica-
tion is
* * required to monitor for Cryptosporidium under §§141.701
to 141.702.
* * serving fewer than 10,000 people and NOT required to
monitor for Cryptosporidium under §142.702(b).
Cryptosporidium < 0.075 oocyst/L
0.075 oocysts/L 3.0 oocysts/L
NA
Bin 1
Bin 2
Bin 3
Bin 4
Bint
Based on calculations in paragraph (a) or (d) of this section, as applicable.
(d) Following completion of the
second round of source water
monitoring required under § 141.702(d),
filtered systems and unfiltered systems
that are required to install filtration
must recalculate their Cryptosporidium
bin concentration using the
Cryptosporidium results reported under
§ 141.702(d) and following the
procedures in paragraphs (b)(l) through
(3) of this section. Systems must then
determine their bin classification a
second time using this Cryptosporidium
bin concentration and the table in
paragraph (c) of this section.
(e) Any filtered system or unfiltered
system that is required to install
filtration that fails to complete the
monitoring requirements of § § 141.701
through 141.707 or choses not to
monitor pursuant to § 141.701(0 must
meet the treatment requirements for Bin
4 under § 141.720 by the date applicable
under § 141.70l(e).
Disinfection Profiling and
Benchmarking Requirements
§141.710 [Reserved].
§ 141.711 Determination of systems
required to profile.
(a) Subpart H of this part community
and nontransient noncommunity water
systems serving at least 10,000 people
that do not have at least 5.5 log of
Cryptosporidium treatment, equivalent
to compliance with Bin 4 in § 141.720,
in place prior to the date when the
system is required to begin profiling in
§ 141.712 are required to develop
Giardia lamblia and virus disinfection
profiles.
(b) Subpart H community and
nontransient noncommunity water
systems serving fewer than 10,000
people that do not have at least 5.5 log
of Cryptosporidium treatment,
equivalent to compliance with Bin 4 in
§ 141.720, in place prior to the date
when the system is required to begin
profiling in § 141.712 are required to
develop Giardia lamblia and virus
disinfection profiles if any of the criteria
in paragraphs (b)(l) through (3) of this
section apply.
(1) TTHM levels in the distribution
system are at least 0.064 mg/L as a
locational running annual average
(LRAA) at any monitoring site. Systems
must base their TTHM LRAA
calculation on data collected for
compliance under subpart L of this part
after [Date of Publication of Final Rule
in the Federal Register], or as
determined by the State. .
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(2) HAAS levels in the distribution
system are at least 0.048 mg/L as an
LRAA at any monitoring site. Systems
must base their HAAS LRAA calculation
on data collected for compliance under
subpart L of this part after [Date of
Publication of Final Rule in the Federal
Register], or as determined by the State.
(3) The system is required to monitor
for Cryptosporidium under § 141.701(c).
(c) In lieu of developing a new profile,
systems may use the profile(s)
developed under § 141.172 or
§ § 141.530 through 141.536 if the
profile(s) meets the requirements of
§141.713(c).
§ 141.712 Schedule for disinfection
profiling requirements.
(a) Systems must comply with the
following schedule in the table in this
paragraph:
SCHEDULE OF REQUIRED DISINFECTION PROFILING MILESTONES 1
Activity
1. Report TTHM and HAAS LRAA
results to State.
2. Begin disinfection profiling1'2 ..
3. Complete disinfection profiling
based on at least one year of
data.
Date
Subpart H systems serving at
least 10,000 people
NA
[Date 24 Months After Date of
Publication of Final Rule in the
Federal Register].
[Date 36 Months After Date of
Publication of Final Rule in the
Federal Register].
Subpart H systems serving fewer than 10,000 people
Required to monitor for
Cryptosporidium
NA
[Date 54 Months After Date of Pub-
lication of Final Rule in the Fed-
eral Register].
[Date 66 Months After Date of Pub-
lication of Final Rule in the Fed-
eral Register].
Not required to monitor for
Cryptosporidium
[Date 42 Months After Date of Pub-
lication of Final Rule in the Fed-
eral Register].
[Date 42 Months After Date of Pub-
lication of Final Rule in the Fed-
eral Register] if required3.
[Date 54 Months After Date of Pub-
lication of Final Rule in the Fed-
eral Register] if required3.
1 Systems with at least 5.5 log of Cryptosporidium treatment in place are not required to do disinfection profiling.
2Systems may use existing operational data and profiles as described in § 141.713(c).
3Systems serving fewer than 10,000 people are not required to conduct disinfection profiling if they are not required to monitor for
Cryptosporidium and if their TTHM and HAAS LRAAs do not exceed the levels specified in §141.711(b).
(b) [Reserved]
§141.713 Developing a profile.
(a) Systems required to develop
disinfection profiles under § 141,711
must follow the requirements of this
section. Systems must monitor at least
weekly for a period of 32 consecutive
months to determeine the total log
inactivation for Giardia lamblia and
viruses. Systems must determine log
inactivation for Giardia lamblia through
the entire plant, based on CTVs values
in Tables 1.1 through 1.6, 2.1 and 3.1 of
§141.74(b) as applicable. Systems must
determine log inactivation for viruses
through the entire treatment plant based
on a protocol approved by the State.
(b) Systems with a single point of
disinfectant application prior to the
entrance to the distribution system must
conduct the monitoring in paragraphs
(b)(l) through (4) of this section.
Systems with more than one point of
disinfectant application must conduct
the monitoring in paragraphs (b)(l)
through (4) of this section for each
disinfection segment. Systems must
monitor the parameters necessary to
determine the total inactivation ratio,
using analytical methods in § 141.74(a).
(1) For systems using a disinfectant
other than UV, the temperature of the
disinfected water must be measured at
each residual disinfectant concentration
sampling point during peak hourly flow
or at an alternative location approved by
the State.
(2) For systems using chlorine, the pH
of the disinfected water must be
measured at each chlorine residual
disinfectant concentration sampling
point during peak hourly flow or at an
alternative location approved by the
State.
(3) The disinfectant contact time(s) (T)
must be determined during peak hourly
flow.
{4J 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.
(c) In lieu of conducting new
monitoring under paragraph (b) of this
section, systems may elect to meet the
requirements of paragrphs (c}(l) or (2) of
this section.
(1) Systems that have at least 12
consecutive months of existing
operational data that are substantially
equivalent to data collected under the
provisions of paragraph (b) of this
section may use these data to develop
disinfection profiles as specified in this
section if the system has neither made
a significant change to its treatment
practice nor changed sources since the
data were collected. Systems using
existing operational data may develop
disinfection profiles for a period of up
to three years.
(2) Systems may use disinfection
profile(s) developed under § 141.172 or
§§ 141.530 through 141.536 in lieu of
developing a new profile if the system
has neither made a significant change to
its treatment practice nor changed
sources since the profile was developed.
Systems that have not developed a virus
profile under § 141.172 or §§ 141.530
through 141.536 must develop a virus
profile using the same monitoring data
on which the Giardia lamblia profile is
based.
(d) Systems must calculate the total
inactivation ratio for Giardia lamblia as
specified in paragraphs (d}(l) through
(3) of this section.
(1) Systems using only one point of
disinfectant application may determine
the total inactivation ratio for the
disinfection segment based on either of
the methods in paragraph (d)(l)[i) or (ii)
of this section.
(i) Determine one inactivation ratio
(CTcalc/CTgg.g) before or at the first
customer during peak hourly flow.
(ii) Determine successive CTcalc/
CT99.9 values, representing sequential
inactivation ratios, between the point of
disinfectant application and a point
before or at the first customer during
peak hourly flow. The system must
calculate the total inactivation ratio by
determining (CTcalc/CT^.g) for each
sequence and then adding the (CTcalc/
CT99.9) values together to determine (2
(CTcaIc/CT99.9)).
(2) Systems using more than one point
of disinfectant application before the
first customer must determine the CT
value of each disinfection segment
immediately prior to the next point of
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47783
disinfectant application, or for the final
segment, before or at the first customer,
during peak hourly flow. The (CTcalc/
0X99.9) value of each segment and
(S(CTcalc/CT99.9)) must be calculated
using the method in paragraph (d)(l)(ii)
of this section.
(3) The system must determine the
total logs of inactivation by multiplying
the value calculated in paragraph (d}(l)
or (d)(2) of this section by 3.0.
(4) Systems must calculate the log of
inactivation for viruses using a protocol
approved by the State.
(5) Systems 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.
§ 141.714 Requirements when making a
significant change in disinfection practice.
(a) A system that is required to
develop a disinfection profile under the
provisions of this subpart and that plans
to make a significant change to its
disinfection practice must calculate a
disinfection benchmark and must notify
the State prior to making such a change.
Significant changes to disinfection
practice are defined in paragraphs (a)(l)
through (4) of this section.
(1} Changes to the point of
disinfection;
(2) Changes to the disinfectant(s) used
in the treatment plant;
(3) Changes to the disinfection
process; and
(4) Any other modification identified
by the State.
(5) Systems must use the procedures
specified in paragraphs (a)(5)(i) and (ii)
of this section to calculate a disinfection
benchmark.
(i) For the year of profiling data
collected and calculated under
§141.713, or for each year with profiles
covering more than one year, systems
must determine the lowest mean
monthly level of both Giardia lamblia
and virus inactivation. Systems must
determine the mean Giardia lamblia and
virus inactivation for each calendar
month for each year of profiling data by
dividing the sum of daily or weekly
Giardia lamblia and virus log
inactivation by the number of values
calculated for that month.
(ii) The disinfection benchmark is the
lowest monthly mean value (for systems
with one year of profiling data) or the
mean of the lowest monthly mean
values (for systems with more than one
year of profiling data) of Giardia lamblia
and virus log inactivation in each year
of profiling data.
(6) Systems must submit the
information in paragraphs (a)(6)(i)
through (iii) of this section when
notifying the State that they are
planning to make a significant change in
disinfection practice.
(i) A description of the proposed
change.
(ii) The disinfection profile and
benchmark for Giardia lamblia and
viruses determined under §§ 141.713
and 141.714.
(iii) An analysis of how the proposed
change will affect the current level of
disinfection.
Treatment Technique Requirements
§141.720 Treatment requirements for
filtered systems.
(a) Filtered systems or systems that
are unfiltered and required to install
filtration must provide the level of
treatment for Cryptosporidium specified
in this paragraph, based on their bin
classification as determined under
§ 141.709 and their existing treatment:
tf the system bin classifica-
tion is ...
(1) Bin 1
(2) Bin 2
(3) Bin 3
(4) Bin 4
And the system uses the following filtration treatment in full compliance with subpart H, P, and T of this section
(as applicable), then the additional treatment requirements are ...
Conventional filtration
treatment (including soft-
ening)
No additional treatment
2.5 log treatment
Direct filtration
No additional treatment
3 log treatment
Slow sand or diatoma-
ceous earth filtration
No additional treatment
1 log treatment
2 log treatment
2.5 log treatment
Alternative filtration tech-
nologies
No additional treatment
(1)
(2)
(3)
1 As determined by the State such that the total Cryptosporidium removal and inactivation is at least 4.0 log.
2 As determined by the State such that the total Cryptosporidium removal and inactivation is at least 5.0 tog.
3 As determined by the State such that the total Cryptosporidium removal and inactivation is at least 5.5 log.
(b) Filtered systems must use one, or
a combination, of the management and
treatment options listed in § 141.722,
termed the microbial toolbox, to meet
the additional Cryptosporidium
treatment requirements identified for
each bin in paragraph (a) of this section.
(c) Systems classified in Bin 3 and Bin
4 must achieve at least 1 log of the
additional treatment required under
paragraph (a) of this section using either
one or a combination of the following:
bag filters, bank filtration, cartridge
filters, chlorine dioxide, membranes,
ozone, and/or UV as specified in
§141.722.
§141.721 Treatment requirements for
unfiltered systems.
(a) Following completion of the initial
source water monitoring required under
§ 141.702(a), unfiltered systems that
meet all filtration avoidance criteria of
§ 141.71 must calculate the arithmetic
mean of all Cryptosporidium sample
concentrations reported under
§ 141.702(a), along with any previously
collected data that satisfy the
requirements of § 141.708, and must
meet the treatment requirements in
paragraph (b)(l) or (2) of this section, as
applicable, based on this concentration.
(b)(l) Unfiltered systems with a mean
Cryptosporidium concentration of 0.01
oocysts/L or less must provide at least
2 log Cryptosporidium inactivation.
(2) Unfiltered systems with a mean
Cryptosporidium concentration of
greater than 0.01 oocysts/L must
provide at least 3 log Cryptosporidium
inactivation.
(c) Unfiltered systems must use
chlorine dioxide, ozone, or UV as
specified in § 141.722 to meet the
Cryptosporidium inactivation
requirements of this section.
(1) Unfiltered systems that use
chlorine dioxide or ozone and fail to
achieve the Cryptosporidium log
inactivation required in paragraph (b){l)
or (2) of this section, as applicable, on
more than one day in the calendar
month are in violation of the treatment
technique requirement.
(2) Unfiltered systems that use UV
light and fail to achieve the
Cryptosporidium log inactivation
required in paragraph (b)(l) or (2) of this
section, as applicable, in at least 95% of
the water that is delivered to the public
during each calendar month, based on
monitoring required under paragraph
§ 141.729(d)(4), are in violation of the
treatment technique requirement.
(d) Unfiltered systems must meet the
combined Cryptosporidium, Giardia
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Federal Register/Vol. 68, No. 154/Monday, August 11, 2003/Proposed Rules
lamblia, and virus inactivation
requirements of this section and
§ 141.72(a) using a minimum of two
disinfectants, and each disinfectant
must separately achieve the total
inactivation required for either
Cryptosporidium, Giardia lamblia, or
viruses.
(e) Following completion of the
second round of source water
monitoring required under § 141.702(d),
unfiltered systems that meet all
filtration avoidance criteria of § 141.71
must calculate the arithmetic mean of
all Cryptosporidium sample
concentrations reported under
§ 141.702(d) and must meet the
treatment requirements in paragraph
(b)(l) or (2) of this section, as
applicable, based on this concentration.
(f) Any unfiltered system that meets
all filtration avoidance criteria of
§ 141.71 and fails to complete the
monitoring requirements of § § 141.701
through 141.707 or choses not to
monitor pursuant to § 141.701(g) must
meet the treatment requirements of
paragraph (b)(2) of this section by the
date applicable under § 141.701(e).
§141.722 Microbial toolbox options for
meeting Cryptosporidium treatment
requirements.
(a) To meet the additional
Cryptosporidium treatment
requirements of §§141.720 and
141.721, systems must use microbial
toolbox options listed in this follwing
table that are designed, implemented,
and operated in accordance with the
requirements of this subpart.
MICROBIAL TOOLBOX: OPTIONS, CREDITS AND CRITERIA
Toolbox option
Proposed Cryptosporidium treatment credit with design and implementation criteria
Source Toolbox Components
(1) Watershed control program
(2) Alternative source/intake man-
agement.
0.5 log credit for State approved program comprising EPA specified elements. Specific criteria are in
§141.725(3).
Bin classification based on concurrent Cryptosporidium monitoring. No presumptive credit. Specific criteria
are in §141J25(b).
Pre-Fi It ration Toolbox Components
(3) Presed[mentation basin with co-
agulation.
(4) Two-stage lime softening
(5) Bank filtration
0.5 log credit for new basins with continuous operation and coagulant addition. No presumptive credit for
basins existing when monitoring is required under §141.702. Specific criteria are in §141.726(a).
0.5 log credit for two-stage softening with coagulant addition. Specific criteria are in § 141.726(b).
0.5 log credit for 25 foot setback; 1.0 log credit for 50 foot setback. No presumptive credit for bank filtration
existing when monitoring is required under §141.704(d)(1). Specific criteria are in §141.726(c).
Treatment Performance Toolbox Components
(6) Combined filter performance
(7) Individual filter performance
(8) Demonstration of performance ..
0.5 log credit for combined filter effluent turbidity £ 0.15 NTU in 95% of samples each month. Specific cri-
teria are in §141.727{a).
1.0 log credit for individual filter effluent turbidity £0.1 NTU in 95% of daily maximum samples each month
and no filter >0.3 NTU in two consecutive measurements. Specific criteria are in §141.727(b).
Credit based on a demonstration to the State through State approved protocol. Specific criteria are in
§141.727(c).
Additional Filtration Toolbox Components
(9) Bag filters ,
(10) Cartridge filters
(11) Membrane filtration
(12) Second stage filtration
(13) Slow sand filers
1 log credit with demonstration of at least 2 log removal efficiency in challenge test; Specific criteria are in
§141.728(a).
2 log credit with demonstration of at least 3 log removal efficiency in challenge test; Specific criteria are in
§141.728(a).
Log removal credit up to the lower value of the removal efficiency demonstrated during the challenge test
or verified by the direct integrity test applied to the system. Specific criteria are in § 141.728(b).
0.5 log credit for a second separate filtration stage in treatment process following coagulation. Specific cri-
teria are in §141.728(c).
2.5 log credit for second separate filtration process. Specific criteria are in § 141.728(d).
Inactivation Toolbox Components
(14) Chlorine dioxide
(15) Ozone
(16) UV
Log credit based on demonstration of compliance with CT table. Specific criteria are in § 141.729(b).
Log credit based on demonstration of compliance with CT table. Specific criteria are in § 141.729(c).
Log credit based on demonstration of compliance with UV dose table. Specific criteria are in § 141.729(d).
(b) Failure to comply with the
requirements of this section in
accordance with the schedule in
§ 141.701(e) is a treatment technique
violation.
§141.723 [Reserved]
§ 141.724 Requirements for uncovered
finished water storage facilities.
(a) Systems using uncovered finished
water storage facilities must comply
with the conditions of one of the
paragraphs (a)(l) through (3) of this
section for each facility no later than the
date specified in §141.701(h).
(1) Systems must cover any uncovered
finished water storage facility.
(2) Systems must treat the discharge
from the uncovered finished water
storage facility to the distribution
system to achieve at least 4 log virus
inactivation using a protocol approved
by the State.
(3) Systems must have a State-
approved risk mitigation plan for the
uncovered finished water storage
facility that addresses physical access
and site security, surface water runoff,
animal and bird waste, and ongoing
water quality assessment, and includes
a schedule for plan implementation.
Systems must implement the risk
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47785
mitigation plan approved by the State.
Systems must submit risk mitigation
plans to the State for approval no later
than [Date 24 Months After Date of
Publication of Final Rule in the Federal
Register].
(b) Failure to comply with the
requirements of this section in
accordance with the schedule in
§ 141.701(h) is a treatment technique
violation.
Requirements for Microbial Toolbox
Components
§ 141.725 Source toolbox components.
(a) Watershed control program.
(1) Systems that intend to qualify for
a 0.5 log credit for Cryptosporidium
removal for a watershed control
program must notify the State no later
than one year after completing the
source water monitoring requirements
of § 141.702(b) that they intend to
develop a watershed control program
and to submit it for State approval.
(2) Systems must submit a proposed
initial watershed control plan and a
request for plan approval and 0.5 log
Cryptosporidium removal credit to the
State no later than two years after
completing the source water monitoring
requirements of § 141.702(b). Based on a
review of the initial proposed watershed
control plan, the State may approve,
reject, or conditionally approve the
plan. If the plan is approved, or if the
system agrees to implement the State's
conditions for approval, the system is
awarded a 0.5 log credit for
Cryptosporidium removal to apply
against additional treatment
requirements.
(3) The application to the State for
initial program approval must include
elements in paragraphs (a)(3)(i) through
(iii) of this section.
(i) An analysis of the vulnerability of
each source to Cryptosporidium. The
vulnerability analysis must address the
watershed upstream of the drinking
water intake and must include the
following: a characterization of the
watershed hydrology, identification of
an "area of influence" (the area to be
considered in future watershed surveys)
outside of which there is no significant
probability of Cryptosporidium or fecal
contamination affecting the drinking
water intake, identification of both
potential and actual sources of
Cryptosporidium contamination, the
relative impact of the sources of
Cryptosporidium contamination on the
system's source water quality, and an
estimate of the seasonal variability of
such contamination.
(ii) An analysis of control measures
that could mitigate the sources of
Cryptosporidium contamination
identified during the vulnerability
analysis. The analysis of control
measures must address their relative
effectiveness in reducing
Cryptosporidium loading to the source
water and their feasability and
sustainability.
(iii) A plan that establishes goals and
defines and prioritizes specific actions
to reduce source water Cryptosporidium
levels. The plan must explain how the
actions are expected to contribute to
specific goals, identify watershed
partners and their role(s), identify
resource requirements and
commitments, and include a schedule
for plan implementation.
(4) Initial State approval of a
watershed control plan and its
associated 0.5 log Cryptosporidium
removal credit is valid until the system
completes the second round of
Cryptosporidium monitoring required
under § 141.702(d). Systems must
complete the actions in paragraphs
(a)(4)(i) through (iv) of this section to
maintain State approval and the 0.5 log
credit.
(i) Submit an annual watershed
control program status report to the
State by a date determined by the State.
The annual watershed control program
status report must describe the system's
implementation of the approved plan
and assess the adequacy of the plan to
meet its goals. It must explain how the
system is addressing any shortcomings
in plan implementation, including those
previously identified by the State or as
the result of the watershed survey
conducted under paragraph (a)(4)(ii) of
this section. If it becomes necessary
during implementation to make
substantial changes in its approved
watershed control program, the system
must notify the State and provide a
rationale prior to making any such
changes. If any change is likely to
reduce the level of source water
protection, the system must also include
the actions it will take to mitigate the
effects in its notification.
(ii) Conduct an annual watershed
sanitary survey and submit the survey
report to the State for approval. The
survey must be conducted according to
State guidelines and by persons
approved by the State to conduct
watershed surveys. The survey must
encompass the area of the watershed
that was identified in the State-
approved watershed control plan as the
area of influence and, at a minimum,
assess the priority activities identified
in the plan and identify any significant
new sources of Cryptosporidium.
{iii) Submit to the State a request for
review and re-approval of the watershed
control program and for a continuation
of the 0.5 log removal credit for a
subsequent approval period. The
request must be provided to the State at
least six months before the current
approval period expires or by a date
previously determined by the State. The
request must include a summary of
activities and issues identified during
the previous approval period and a
revised plan that addresses activities for
the next approval period, including any
new actual or potential sources of
Cryptosporidium contamination and
details of any proposed or expected
changes from the existing State-
approved program. The plan must
address goals, prioritize specific actions
to reduce source water
Cryptosporidium, explain how actions
are expected to contribute to achieving
goals, identify partners and their role(s),
resource requirements and
commitments, and the schedule for plan
implementation.
(iv) The annual status reports,
watershed control plan and annual
watershed sanitary surveys must be
made available to the public upon
request. These documents must be in a
plain language style and include criteria
by which to evaluate the success of the
program in achieving plan goals. If
approved by the State, the system may
withhold portions of the annual status
report, watershed control plan, and
watershed sanitary survey based on
security considerations.
(5) Unfiltered systems may not claim
credit for Cryptosporidium removal
under this option.
(b) Alternative source. (1) If approved
by the State, a system may be classified
in a bin under § 141.709 based on
monitoring that is conducted
concurrently with source water
monitoring under § 141.701 and reflects
a different intake location (either in the
same source or for an alternate source)
or a different procedure for managing
the timing or level of withdrawal from
the source.
(2) Sampling and analysis of
Cryptosporidium in the concurrent
round of monitoring must conform to
the requirements for monitoring
conducted under this subpart to
determine bin classification. Systems
must submit the results of all
monitoring to the State, along with
supporting information documenting
the operating conditions under which
the samples were collected.
(3) If me State classifies the system in
a bin based on monitoring that reflects
a different intake location or a different
procedure for managing the timing or
level of withdrawal from the source, the
system must relocate the intake or use
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the intake management strategy, as
applicable, no later than the applicable
date for treatment technique
implementation in § 141.701. The State
may specify reporting requirements to
verify operational practices.
§ 141.726 Pre-filtration treatment toolbox
components.
(a) Presedimentation. New
presedimentation basins that meet the
criteria in paragraphs (a)(l) through (4)
of this section are eligible for 0.5 log
Cryptosporidium removal credit.
Systems with presedimentation basins
existing when the system is required to
conduct monitoring under § 141.702(a)
may not claim this credit and, during
periods when the basins are in use,
must collect samples after the basins for
the purpose of determining bin
classification under §141.709.
(1) The presedimentation basin must
be in continuous operation and must
treat all of the flow reaching the
treatment plant.
(2) The system must continuously add
a coagulant to the presedimentation
basin.
(3) Presedimentation basin influent
and effluent turbidity must be measured
at least once per day or more frequently
as determined by the State.
(4) The system must demonstrate on
a monthly basis at least 0.5 log
reduction of influent turbidity through
the presedimentation process in at least
11 of the 12 previous consecutive
months.
(i) The monthly demonstration of
turbidity reduction must be based on
the mean of daily turbidity readings
collected under paragraph (a)(3) of this
section and calculated as follows:
logio(monthly mean of daily influent
turbidity)—logiolmonthly mean of daily
effluent turbidity).
(ii) If the presedimentation process
has not been in operation for 12 months,
the system must verify on a monthly
basis at least 0.5 log reduction of
influent turbidity through the
presedimentation process, calculated as
specified in this paragraph, for at least
all but any one of the months of
operation.
(b) Two-stage lime softening. Systems
that operate a two-stage lime softening
plant are eligible for an additional 0.5
log Cryptosporidium removal credit if
there is a second clarification step
between the primary clarifier and
filter{s) that is operated continuously.
Both clarifiers must treat all of the plant
flow and a coagulant, which may be
excess lime or magnesium hydroxide,
must be present in both clarifiers.
(c) Bank filtration. New bank filtration
that serves as pretreatment to a filtration
plant is eligible for either a 0.5 or a 1.0
log Cryptosporidium removal credit
towards the requirements of this subpart
if it meets the design criteria specified
in paragraphs (c)(l) through (c)(5) of this
section and the monitoring and
reporting criteria of paragraph (c)(6) of
this section. Wells with a ground water
flow path of at least 25 feet are eligible
for 0.5 log removal credit; wells with a
ground water flow path of at least 50
feet are eligible for 1.0 log removal
credit. The ground water flow path must
be determined as specified in paragraph
(c)(5) of this section.
(1) Only horizontal and vertical wells
are eligible for bank filtration removal
credit.
(2) Only wells in granular aquifers are
eligible for bank filtration removal
credit. Granular aquifers are those
comprised of sand, clay, silt, rock
fragments, pebbles or larger particles,
and minor cement. The aquifer material
must be unconsolidated as
demonstrated by the aquifer
characterization specified in paragraph
(c)(3) of this section, unless the system
meets the conditions of paragraph (c)(4)
of this section. Wells located in
consolidated aquifers, fractured
bedrock, karst limestone, and gravel
aquifers are not eligible for bank
filtration removal credit.
(3) A system seeking removal credit
for bank filtration must characterize the
aquifer at the well site to determine
aquifer properties. The aquifer
characterization must include the
collection of relatively undisturbed
continuous core samples from the
surface to a depth at least equal to the
bottom of the well screen. The
recovered core length must be at least 90
percent of the total projected depth to
the well screen, and each sampled
interval must be a composite of no more
than 2 feet in length. A well is eligible
for removal credit if at least 90 percent
of the composited intervals from the
aquifer contain at least 10 percent fine
grained material, which is defined as
grains less than 1.0 mm in diameter.
(4) Wells constructed in partially
consolidated granular aquifers are
eligible for removal credit if approved
by the State based on a demonstraton by
the system that the aquifer provides
sufficient natural filtration. The
demonstration must include a
characterization of the extent of
cementation and fractures present in the
aquifer.
(5) For vertical wells, the ground
water flow path is the measured
horizontal distance from the edge of the
surface water body to the well. This
horzontal distance to the surface water
must be determined using the floodway
boundary or 100 year flood elevation
boundary as delineated on Federal
Emergency Management Agency
(FEMA) Flood Insurance Rate maps. If
the floodway boundary or 100 year
flood elevation boundary is not
delineated, systems must determine the
floodway or 100 year flood elevation
boundary using methods substantially
equilvalent to those used in preparing
FEMA Flood Insurance Rate maps. For
horizontal wells, the ground water flow
path is the closest measured distance
from the bed of the river under normal
flow conditions to the closest horizontal
well lateral intake.
(6) Turbidity measurements must be
performed on representative samples
from each wellhead at least every four
hours that the bank filtration is in
operation. Continuous turbidity
monitoring at each wellhead may be
used if the system validates the
continuous measurement for accuracy
on a regular basis using a protocol
approved by the State. If the monthly
average of daily maximum turbidity
values at any well exceeds 1 NTU, the
system must report this finding to the
State within 30 days. In addition, within
30 days of the exceedance, the system
must conduct an assessment to
determine the cause of the high
turbidity levels and submit that
assessment to the State for a
determination of whether any
previously allowed credit is still
appropriate.
(7) Systems with bank filtration that
serves as pretreatment to a filtration
plant and that exists when the system is
required to conduct monitoring under
§ 141,702(a) may not claim this credit.
During periods when the bank filtration
is in use, systems must collect samples
after the bank filtration for the purpose
of determining bin classification under
§141.709.
§141.727 Treatment performance toolbox
components.
(a) Combined filter performance.
Systems using conventional filtration
treatment or direct filtration treatment
may claim an additional 0.5 log
Cryptosporidium removal credit for any
month at each plant that demonstrates
that combined filter effluent (CFE)
turbidity levels are less than or equal to
0.15 NTU in at least 95 percent of the
measurements taken each month, based
on sample measurements collected
under §§ 141.73,141.173(a) and
141.551. Systems may not claim credit
under this paragraph and paragraph (b)
in the same month.
(b) Individual filter performance.
Systems using conventional filtration
treatment or direct filtration treatment
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47787
may claim an additional 1.0 log
Cryptosporidiutn removal credit for any
month at each plant that meets both the
individual filter effluent (IFE) turbidity
requirements of paragraphs (b)(l) and
(2) of this section, based on monitoring
conducted under § § 141.174(a) and
141.560.
(1} IFE turbidity must be less than 0.1
MTU in at least 95% of the maximum
daily values recorded at each filter in
each month, excluding the 15 minute
period following return to service from
a filter backwash.
(2) No individual filter may have a
measured turbidity greater than 0.3 NTU
in two consecutive measurements taken
15 minutes apart.
(c)(l) Demonstration of performance.
Systems may demonstrate to the State,
through the use of State-approved
protocols, that a plant, or unit process
of a plant, achieves a mean
Cryptosporidium removal efficiency
greater than any presumptive credit
specified under § 141.720 or § § 141.725
through 141.728. Systems are eligible
for an increased Cryptosporidium
removal credit if the State determines
that the plant or process can reliably
achieve such a removal efficiency on a
continuing basis and the State provides
written notification of its determination
to the system. States may establish
ongoing monitoring and/or performance
requirements the State determines are
necessary to demonstrate the greater
credit and may require the system to
report operational data on a monthly
basis to verify that conditions under
which the demonstration of
performance was awarded are
maintained during routine operations. If
the State determines that a plant, or unit
process of a plant, achieves an average
Cryptosporidium removal efficiency less
than any presumptive credit specified
under § 141.720 or § § 141.725 through
141.728, the State may assign the lower
credit to the plant or unit process.
(2) Systems may not claim
presumptive credit for any toolbox box
component in §§141.726,141.727(a)
and (b), or 141,728 if that component is
also included in the demonstration of
performance credit.
§141.728 Additional filtration toolbox
components.
(a) Bag and cartridge filters. Systems
are eligible for a 1 log Cryptosporidium
removal credit for bag filters and a 2 log
Cryptosporidium removal credit for
cartridge filters by meeting the criteria
in paragraphs (a)(l) through (a)(10) of
this section. The request to the State for
this credit must include the results of
challenge testing that meets the
requirements of paragraphs (a)(2)
through (a)(9) of this section.
(1) To receive a 1 log Cryptosporidium
removal credit for a bag filter, the filter
must demonstrate a removal efficiency
of 2 log or greater for Cryptosporidium.
To receive a 2 log Cryptosporidium
removal credit for a cartridge filter, the
filter must demonstrate a removal
efficiency of 3 log or greater for
Cryptosporidium. Removal efficiency
must be demonstrated through
challenge testing conducted according
to the criteria in paragraphs (a)(2)
through (a)(9) of this section. The State
may accept data from challenge testing
conducted prior to [Date of Publication
of Final Rule in the Federal Register] in
lieu of additional testing if the prior
testing was consistent with the criteria
specified in paragraphs (a)(2) through
(a)(9) of this section.
(2) Challenge testing must be
performed on full-scale bag or cartridge
filters that are identical in material and
construction to the filters proposed for
use in full-scale treatment facilities for
removal of Cryptosporidium.
(3) Challenge testing must be
conducted using Cryptosporidium
oocysts or a surrogate that is removed
no more efficiently than
Cryptosporidium oocysts. The organism
or surrogate used during challenge
testing is referred to as the challenge
particulate. The concentration of the
challenge particulate must be
determined using a method capable of
discreetly quantifying the specific
organism or surrogate used in the test;
gross measurements such as turbidity
may not be used.
(4) The maximum feed water
concentration that can be used during a
challenge test must be based on the
detection limit of the challenge
particulate in the filtrate (i.e., filtrate
detection limit) and must be calculated
using the equation in either paragraph
(a)(4)(i) or (a)(4)(ii) of this section as
applicable.
(i) For cartridge filters: Maximum
Feed Concentration = 3.16xlO4 x
(Filtrate Detection Limit).
(ii) For bag filters: Maximum Feed
Concentration = 3.16xl03 x (Filtrate
Detection Limit).
(5) Challenge testing must be
conducted at the maximum design flow
rate for the filter as specified by the
manufacturer.
(6) Each filter evaluated must be
tested for a duration sufficient to reach
100 percent of the terminal pressure
drop, which establishes the maximum
pressure drop under which the filter
may be used to comply with the
requirements of this subpart.
(7) Each filter evaluated must be
challenged with the challenge
particulate during three periods over the
filtration cycle: within two hours of
start-up after a new bag or cartridge
filter has been installed; when the
pressure drop is between 45 and 55
percent of the terminal pressure drop;
and at the end of the run after the
pressure drop has reached 100 percent
of the terminal pressure drop.
(8) Removal efficiency of a bag or
cartridge filter must be determined from
the results of the challenge test and
expressed in terms of log removal values
using the following equation:
LRV = LOG,o(Cf)-LOG10(Cp)
where LRV = log removal value
demonstrated during challenge testing;
Cf = the feed concentration used during
the challenge test; and Cp = the filtrate
concentration observed during the
challenge test. In applying this equation,
the same units must be used for the feed
and filtrate concentrations. If the
challenge participate is not detected in
the filtrate, then the term Cp must be set
equal to the detection limit. An LRV
must be calculated for each filter
evaluated during the testing.
(9) If fewer than 20 filters are tested,
the removal efficiency for the filtration
device must be set equal to the lowest
of the representative LRVs among the
filters tested. If 20 or more filters are
tested, then removal efficiency of the
filtration device must be set equal to the
10th percentile of the representative
LRVs among the various filters tested.
The percentile is defined by (i/(n+l))
where i is the rank of n individual data
points ordered lowest to highest. If
necessary, the system may calculate the
10th percentile using linear
interpolation.
(10) If a previously tested bag or
cartidge filter is modified in a manner
that could change the removal efficiency
of the filter, addition challenge testing
to demonstrate the removal efficiency of
the modified filter must be conducted
and submitted to the State.
(b) Membrane filtration. (1) Systems
using a membrane filtration process,
including a membrane cartridge filter
that meets the definition of membrane
filtration and the integrity testing
requirements of this subpart, are eligible
for a Cryptosporidium removal credit
equal to the lower value of paragraph
(b)(l)(i) or (b)(l) (ii) of this section:
(i) The removal efficiency
demonstrated during challenge testing
conducted under the conditions in
paragraph (b)(2) of this section.
(ii) The maximum removal efficiency
that can be verified through direct
integrity testing used with the
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47788
Federal Register/Vol. 68, No. 154/Monday, August 11, 2003/Proposed Rules
membrane filtration process under the
conditions in paragraph (b)(3) of this
section.
(2) Challenge Testing. The membrane
used by the system must undergo
challenge testing to evaluate removal
efficiency, and the system must submit
the results of challenge testing to the
State. Challenge testing must be
conducted according to the criteria in .
paragraphs (b)(2)(i) through (b)(2)(vii) of
this section. The State may accept data
from challenge testing conducted prior
to [Date of Publication of Final Rule in
the Federal Register] in lieu of
additional testing if the prior testing was
consistent with the criteria in
paragraphs (b)(2)(i) through (b}(2) (vii)
of this section.
(i) Challenge testing must be
conducted on either a full-scale
membrane module, identical in material
and construction to the membrane
modules used in the system's treatment
facility, or a smaller-scale membrane
module, identical in material and
similar in construction to the full-scale
module,
(ii) Challenge testing must be
conducted using Cryptosporidium
oocysts or a surrogate that is removed
no more efficiently than
Cryptosporidium oocysts. The organism
or surrogate used during challenge
testing is referred to as the challenge
particulate. The concentration of the
challenge particulate must be
determined using a method capable of
discretely quantifying the specific
challenge particulate used in the test;
gross measurements such as turbidity
may not be used.
(iii) The maximum feed water
concentration that can be used during a
challenge test is based on the detection
limit of the challenge particulate in the
filtrate and must be determined
according to the following equation:
Maximum Feed Concentration =
3.16X106 x (Filtrate Detection Limit)
(iv) Challenge testing must be
conducted under representative
hydraulic conditions at the maximum
design flux and maximum design
process recovery specified by the
manufacture for the membrane module.
Flux is defined as the rate of flow per
unit of membrane area. Recovery is
defined as the ratio of filtrate volume
produced by a membrane to feed water
volume applied to a membrane over the
course of an uninterrupted operating
cycle. An operating cycle is bounded by
two consecutive backwash or cleaning
events. For the purpose of challenge
testing in this section, recovery does not
consider losses that occur due to the use
of filtrate in backwashing or cleaning
operations.
(v) Removal efficiency of a membrane
module during challenge testing must
be determined as a log removal using
the following equation:
= LOGio(Cf) - LOG,o(Cp)
where LRV = log removal value
demonstrated during challenge testing;
Cr = the feed concentration used during
the challenge test; and Cp - the filtrate
concentration observed during the
challenge test. Equivalent units must be
used for the feed and filtrate
concentrations. If the challenge
particulate is not detected in the filtrate,
the term Cp is set equal to the detection
limit. An LRV must be calculated for
each membrane module evaluated
during the test.
(vi) The removal efficiency of a
membrane filtration process
demonstrated during challenge testing
must be expressed as a log removal
value (LRVc-Tcst). If fewer than 20
modules are tested, then LRVC-Tcsi is
equal to the lowest of the representative
LRVs among the applicable modules
tested. If 20 or more modules are tested,
then LRVc-Tesi is equal to the 10th
percentile of the representative LRVs
among the applicable modules tested.
The percentile is defined by (i/(n+l))
where i is the rank of n individual data
points ordered lowest to highest. If
necessary, the 10th percentile may be
calculated using linear interpolation.
(vii) The challenge test must establish
a quality control release value (QCRV)
for a non-destructive performance test
that demonstrates the Cryptosporidium
removal capability of the membrane
filtration process. This performance test
must be applied to each production
membrane module used by the system
that did not undergo a challenge test in
order to verify Cryptosporidium removal
capability. Production modules that do
not meet the established QCRV are not
eligible for the removal credit
demonstrated during the challenge test.
(viii) If a previously tested membrane
is modified in a manner that could
change the removal efficiency of the
membrane or the applicability of the
non-destructive performance test and
associated QCRV, addition challenge
testing to demonstrate the removal
efficiency of, and determine a new
QCRV for, the modified membrane must
be conducted and submitted to the
State.
(3) Direct integrity testing. Systems
must conduct direct integrity testing in
a manner that demonstrates a removal
efficiency equal to or greater than the
removal credit awarded to the
membrane filtration process and meets
the requirements described in
paragraphs (b)(3)(i) through (b)(3)(vi) of
this section.
(i) The direct integrity test must be
independently applied to each
membrane unit in service. A membrane
unit is a group of membrane modules
that share common valving that allows
the unit to be isolated from the rest of
the system for the purpose of integrity
testing or maintenance.
(ii) The direct integrity method must
have a resolution of 3 um or less, where
resolution is defined as the smallest leak
size that contributes to a response from
the direct integrity test.
(iii) The system must demonstrate
that the direct integrity test can verify
the log removal credit awarded to the
membrane filtration process by the State
using the approach in either paragraph
(b)(2)(iii)(A) or (b}(2)(iii)(B) of this
section as applicable based on the type
of direct integrity test.
(A) For direct integrity tests that use
an applied pressure or vacuum, the
maximum log removal value that can be
verified by the test must be calculated
according to the following equation:
LRVplT = LOGIO(Qp /(VCF X Qbreach))
where LRVou = maximum log removal
value that can be verified by a direct
integrity test; Qp = total design filtrate
flow from the membrane unit; Qbicach =
flow of water from an integrity breach
associated with the smallest integrity
test response that can be reliably
measured, and VCF = volumetric
concentration factor. The volumetric
concentration factor is the ratio of the
suspended solids concentration on the
high pressure side of the membrane
relative to that in the feed water.
(B) For direct integrity tests that use
a particulate or molecular marker, the
maximum log removal value that can be
verified by the test must be calculated
according to the following equation:
LRVDJT = LOG, o(Cf) - LOG, 0(CP)
where LRVoir = maximum log removal
value that can be verified by a direct
integrity test; Cf = the typical feed
concentration of the marker used in the
test; and Cp - the filtrate concentration
of the marker from an integral
membrane unit.
(iv) Systems must establish a control
limit for the direct integrity test that is
indicative of an integral membrane unit
capable of meeting the removal credit
awarded by the State.
(v) If the result of a direct integrity
test is outside the control limit
established under paragraphs (b)(3)(i)
through (b)(3)(iv) of this section, the
membrane unit must be removed from
service. A direct integrity test must be
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Federal Register/Vol. 68, No. 154/Monday, August 11, 2003/Proposed
47789
conducted to verify any repairs, and the
membrane unit may be returned to
service only if the direct integrity test is
within the established control limit.
(vi) Direct integrity testing must be
conducted on each membrane unit at a
frequency of not less than once each day
that the membrane unit is in operation.
(4) Indirect integrity monitoring.
Systems must conduct continuous
indirect integrity monitoring on each
membrane unit according to the criteria
in paragraphs (b)(4)(i) through (b)(4)(v)
of this section. A system that
implements continuous direct integrity
testing of membrane units in accordance
with the criteria in paragraphs (b)(3)(i)
through (b)(3)(v) of this section is not
subject to the requirements for
continuous indirect integrity
monitoring.
(ij Unless the State approves an
alternative parameter, continuous
indirect integrity monitoring must
include continuous filtrate turbidity
monitoring.
(ii) Continuous monitoring must be
conducted at a frequency of no less than
once every 15 minutes.
(iii) Continuous monitoring must be
separately conducted on each
membrane unit.
(iv) If indirect integrity monitoring
includes turbidity and if the filtrate
turbidity readings are above 0.15 NTU
for a period greater than 15 minutes (i.e.,
two consecutive 15-minute readings
above 0.15 NTU), direct integrity testing
must be performed on the associated
membrane units as specified in
paragraphs (b){3)(i) through (b)(3)(v) of
this section.
(v) If indirect integrity monitoring
includes a State-approved alternative
parameter and if the alternative
parameter exceeds a State-approved
control limit for a period greater than 15
minutes, direct integrity testing must be
performed on the associated membrane
units as specified in paragraphs (b)(3)(i)
through (b)(3)(v) of this section.
(c) Second stage filtration. Systems
are eligible for an additional 0.5 log
Cryptosporidium removal credit if they
have a separate second stage filtration
process consisting of rapid sand, dual
media, GAG, or other fine grain media
in a separate stage following rapid sand
or dual media filtration. To be eligible
for this credit, the first stage of filtration
must be preceded by a coagulation step
and both filtration stages must treat
100% of the flow. A cap, such as GAG,
on a single stage of filtration is not
eligible for this credit.
(d) Slow sand filtration. Systems may
claim a 2.5 log Cryptosporidium
removal credit for a slow sand filtration
process that follows another separate
filtration process if all the flow is
treated by both processes and no
disinfectant residual is present in the
influent water to the slow sand filtration
process.
§141.729 Inactivation toolbox
components.
(a) Calculation ofCTvalues. (1) CT is
the product of the disinfectant contact
time (T, in minutes) and disinfectant
concentration (C, in milligrams per
liter). Systems must calculate CT at least
once each day, with both C and T
measured during peak hourly flow as
specified in §§ 141.74(a) and 141.74(b).
(2) Systems with several disinfection
segments (a segment is defined as a
treatment unit process with a
measurable disinfectant residual level
and a liquid volume) in sequence along
the treatment train, may calculate the
CT for each disinfection segment and
use the sum of the Cryptosporidium log
inactivation values achieved through
the plant.
(b) CT values for chlorine dioxide, (I)
Systems using chlorine dioxide must
calculate CT in accordance with
§141.729(a).
(2) Unless the State approves
alternative CT values for a system under
paragraph (b)(3) of this section, systems
must use the following table to
determine Cryptosporidium log
inactivation credit:
CT VALUES FOR Cryptosporidium INACTIVATION BY CHLORINE DIOXIDE
Log credit
Water Temperature, ° C1
<=0.5
10
15
20
25
0.5
1.0
1 5
2 0
2.5
3.0
319
637
956
1275
1594
1912
305
610
915
1220
1525
1830
279
558
838
1117
1396
1675
256
511
767
1023
1278
1534
214
429
643
858
1072
1286
180
360
539
719
899
1079
138
277
415
553
691
830
89
179
268
357
447
536
58
116
174
232
289
347
38
75
113
150
188
226
1 CT values between the indicated temperatures may be determined by interpolation.
(3) Systems may conduct a site-
specific inactivation study to determine
the CT values necessary to meet a
specified Cryptosporidium log
inactivation level, using a State-
approved protocol. The alternative CT
values determined from the site-specific
study and the method of calculation
must be approved by the State.
(c) CT values for ozone. (1) Systems
using ozone must calculate CT in
accordance with § 141.729(a).
(2) Unless the State approves
alternative CT values for a system under
paragraph (c)(3) of this section, systems
must use the following table to
determine Cryptosporidium log
inactivation credit:
CT VALUES FOR Cryptosporidium INACTIVATION BY OZONE
Log credit
0.5
1.0
1 5
20
2.5
Water Temperature, °C1 1
<=0.5
12
24
36
48
60
1
12
23
35
46
58
2
10
21
31
42
52
3
9.5
19
29
38
48
5
7.9
16
24
32
40
7
6.5
13
20
26
33
10
4.9
9.9
15
20
25
15
3.1
6.2
9.3
12
16
20
2.0
3.9
5.9
7.8
9.8
25
1.2
2.5
3.7
4.9
6.2
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Federal Register/Vol. 68, No. 154/Monday, August 11, 2003/Proposed Rules
CT VALUES FOR Cryptosporidium INACTIVATION BY OZONE—Continued
Water Temperature, °C1
3.0
<=0.5
72
1
69
2
63
3
57
5
47
7
39
10
30
15
19
20
12
25
7.4
CT values between the indicated temperatures may be determined by interpolation
(3) Systems may conduct a site-
specific inactivation study to determine
the CT values necessary to meet a
specified Cryptosporidium log
inactivation level, using a State-
approved protocol. The alternative CT
values determined from the site-specific
study and the method of calculation
must be approved by the State.
(d) Ultraviolet light. (1) Systems may
claim credit for ultraviolet (UV)
processes for inactivation of
Cryptosporidium, Giardia lamblia, and
viruses. The allowable inactivation
credit for each pathogen must be based
on the UV dose delivered by the
system's UV reactors in relation to the
UV dose table in paragraph (d)(2) of this
section.
(2) UV dose table. The log credits
given in this UV dose table are for UV
light at a wavelength of 254 nm as
produced by a low pressure mercury
vapor lamp. Systems may apply this
table to UV reactors with other lamp
types through reactor validation testing
(i.e., performance demonstration) as
described in paragraph (d)(3) of this
section. The UV dose values in this
table are applicable only to post-filter
application of UV in systems that filter
under subpart H of this part and to
unfiltered systems meeting the filtration
avoidance criteria in subparts H, P, and
T of this part:
UV DOSE TABLE FOR Cryptosporidium, GIARDIA LAMBLIA, AND VIRUS INACTIVATION CREDIT
Log credit
0 5
1 o
1 5
2 0
25
3 0
3 5
40
Cryptosporidium
UV Dose (mJ/
cm2)
1.6
2.5
3.9
5.8
8.5
12
NA
NA
Giardia lamblia
UV dose (mJ/
cm2)
1.5
2.1
3.0
5.2
7.7
11
NA
NA
Virus UV dose
{mJ/cm 2)
39
58
79
100
121
143
163
186
(3) Reactor validation testing. For a
system to receive inactivation credit for
a UV reactor, the reactor must undergo
the validation testing in paragraphs
(d)(3)(i) and (d)(3)(ii) of this section,
unless the State approves an alternative
approach. The validation testing must
demonstrate the operating conditions
under which the reactor can deliver the
LTV dose required in paragraph (d)(2) of
this section.
(i) Validation testing of UV reactors
must determine a range of operating
conditions that can be monitored by the
system and under which the reactor
delivers the required UV dose. At a
minimum, these operating conditions
must include flow rate, UV intensity as
measured by a UV sensor, and UV lamp
status. The validated operating
conditions determined by this testing
must account for the following: UV
absorbance of the water; lamp fouling
and aging; measurement uncertainty of
on-line sensors; UV dose distributions
arising from the velocity profiles
through the reactor; failure of UV lamps
or other critical system components;
and inlet and outlet piping or channel
configurations of the UV reactor.
(ii) Validation testing must include
the following: full scale testing of a
reactor that conforms uniformly to the
UV reactors used by the system; and
inactivation of a test microorganism
whose dose response characteristics
have been quantified with a low
pressure mercury vapor lamp.
(4) Reactor monitoring. Systems must
monitor their UV reactors to
demonstrate that they are operating
within the range of conditions that were
validated by the testing described in
paragraphs (d)(3)(ij and (d)(3)(ii) of this
section to achieve the required UV dose
in paragraph (d)(2) of this section.
Systems must monitor for UV intensity
as measured by a UV sensor, flow rate,
and lamp outage and for any other
parameters required by the State.
Systems must verify the calibration of
UV sensors and must recalibrate sensors
in accordance with a protocol approved
by the State.
Reporting and Recordkeeping
Requirements
§141.730 Reporting requirements.
(a) Systems must follow the
requirements for reporting sampling
schedules under § 141.703 and for
reporting source water monitoring
results under § 141.707 unless they
notify the State that they will not
conduct source water monitoring due to
meeting the criteria of § 141.701{f) or (g).
(b) Systems using uncovered finished
water storage facilities must notify the
State of the use of each facility no later
than [Date 24 Months After Date of
Publication of Final Rule in the Federal
Register].
(c) Filtered systems and unfiltered
systems that are required to install
filtration must report their
Cryptosporidium bin classification, as
determined under using the procedures
in § 141.709, to the State by the
applicable dates in paragraph (c)(l) or
(2) of this section.
(1) Systems that serve at least 10,000
people must report their initial bin
classification no later than [Date 36
Months After Date of Publication of
Final Rule in the Federal Register] and
must report their bin classification
determined using results from the
second round of source water
monitoring no later than [Date 138
Months After Date of Publication of
Final Rule in the Federal Register].
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47791
(2) Systems that serve fewer than
10,000 people must report their initial
bin classification no later than [Date 66
Months After Date of Publication of
Final Rule in the Federal Register] and
must report their bin classification
determined using results from the
second round of source water
monitoring no later than [Date 174
Months After Date of Publication of
Final Rule in the Federal Register].
(d) Unfiltered systems that meet all
filtration avoidance criteria of §141.71
must report their mean Cryptosporidium
concentration, as determined under
§ 141.721, to the State by the applicable
dates in paragraph (d)(l) or (2) of this
section.
(1) Systems that serve at least 10,000
people must report their initial mean
Cryptosporidium concentration no later
than [Date 36 Months After Date of
Publication of Final Rule in the Federal
Register] and must report their mean
Cryptosporidium concentration
determined using results from Ae
second round of source water
monitoring no later than [Date 138
Months After Date of Publication of
Final Rule in the Federal Register].
(2) Systems that serve fewer than
10,000 people must report their initial
mean Cryptosporidium concentration no
later than [Date 66 Months After Date of
Publication of Final Rule in the Federal
Register] and must report their mean
Cryptosporidium concentration
determined using results from the
second round of source water
monitoring no later than [Date 174
Months After Date of Publication of
Final Rule in the Federal Register],
(e) Systems must report to the State in
accordance with the following table in
this paragraph for any toolbox options
used to comply with the
Cryptosporidium treatment technique
requirements under § 141.720 or
§ 141.721. The State may place
additional reporting requirements it
determines to be necessary to verify
operation in accordance with required
criteria for all toolbox options:
MICROBIAL TOOLBOX REPORTING REQUIREMENTS
Toolbox option
Systems must submit the fol-
lowing information
On the following schedule1—sys-
tems serving > 10,000 people
On the following schedule1—sys-
tems serving < 10,000 people
(1) Watershed control program
(WCP).
(2) Bank filtration
(3) Presedimentation
(4) Two-sage lime softening
(i) Notify State of intention to de-
velop WCP.
(ii) Submit initial WCP plan to
State.
(iii) Annual report and State-ap-
proved watershed survey report.
(iv) Request for re-approval and
report on the previous approval
period.
(i) Initial demonstration of the fol-
lowing: unconsolidated, pre-
dominantly sandy aquifer and
setback distance of at least 25
ft. {0.5 log credit) or 50 ft. (1.0
log credit).
(ii) If monthly average of daily
max turbidity is greater than 1
NTU then system must report
result and submit an assess-
ment of the cause.
Monthly verification of the fol-
lowing; Continuous basin oper-
ation; treatment of 100% of the
flow; continuous addition of a
coagulant; and at least 0.5 log
removal of influent turbidity
based on the monthly mean of
daily turbidity readings for 11 of
the 12 previous months.
Monthly verification of the fol-
lowing: Continuous operation of
a second clarification step be-
tween the primary clarifier and
filter; continuous presence of a
coagulant in both primary and
secondary clarifiers; and both
clarifiers treated 100% of the
plant flow.
No later than [Date 48 Months
After Date of Publication of
Final Rule in the Federal Reg-
ister].
No later than [Date 60 Months
After Date of Publication of
Final Rule in the Federal Reg-
ister].
By a date determined by the
State, every 12 months, begin-
ning on [Date 84 Months After
Date of Publication of Final
Rule in the Federal Register].
Six months prior to the end of the
current approval period or by a
date previously determined by
the State.
Initial demonstration no later than
[Date 72 Months after Date of
Publication of Final Rule in the
Federal Register].
Report within 30 days following
the month in which the moni-
toring was conducted, begin-
ning on [Date 72 Months After
Date of Publication of Final
Rule in the Federal Register].
Monthly reporting within 10 days
following the month in which
the monitoring was conducted,
beginning on [Date 72 Months
After Date of Publication of
Final Rule in the Federal Reg-
ister],
Monthly reporting within 10 days
following the month in which
the monitoring was conducted,
beginning on [Date 72 Months
After Date of Publication of
Final Rule in the Federal Reg-
ister].
No later than [Date 78 Months
After Date of Publication of
Final Rule in the Federal Reg-
ister].
No later -than [Date 90 Months
After Date of Publication of
Final Rule in the Federal Reg-
ister].
By a date determined by the
State, every 12 months, begin-
ning on [Date 114 Months After
Date of Publication of Final
Rule in the Federal Register].
Six months prior to the end of the
current approval period or by a
date previously determined by
the State.
Initial demonstration no later than
[Date 102 Months after Date of
Publication of Final Rule in the
Federal Register].
Report within 30 days following
the month in which the moni-
toring was conducted, begin-
ning on [Date 102 Months After
Date of Publication of Final
Rule in the Federal Register].
Monthly reporting within 10 days
following the month in which
the monitoring was conducted,
beginning on [Date 102 Months
After Date of Publication of
Final Rule in the Federal Reg-
ister].
Monthly reporting within 10 days
following the month in which
the monitoring was conducted,
beginning on [Date 102 Months
After Date of Publication of
Final Rule in the Federal Reg-
ister].
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47792
Federal Register/Vol. 68, No. 154/Monday, August 11, 2003/Proposed Rules
MICROBIAL TOOLBOX REPORTING REQUIREMENTS—Continued
Toolbox option
Systems must submit the fol-
lowing information
On the following schedule1—sys-
tems serving > 10,000 people
On the following schedule1—sys-
tems serving < 10,000 people
(5) Combined filter performance
(6) Individual filter performance
(7) Membrane filtration
(8) Bag filters and cartridge filters
(9) Second stage filtration
(10) Slow and filtration
(11) Chlorine dioxide
Monthly verification of combined
filter effluent (CFE) turbidity lev-
els less than or equal to 0.15
NTU in at least 95 percent of
the 4 hour CFE measurements
taken each month.
Monthly verification of the fol-
lowing: Individual filter effluent
(IFE) turbidity levels less than
or equal to 0.1 NTU in at least
95 percent of all daily maximum
IFE measurements taken each
month (excluding 15 min period
following start-up after back-
wash); and no individual filter
greater than 0.3 NTU in two
consecutive readings 15 min-
utes apart.
(i) Results of verification testing
demonstrating the following:
Removal efficiency established
through challenge testing that
meets criteria in this subpart;
and integrity testing and associ-
ated baseline.
(ii) Monthly report summarizing all
direct integrity tests above the
control limit and, if applicable,
any indirect integrity monitoring
results triggering direct integrity
testing and the corrective action
that was taken.
(i) Demonstration that the fol-
lowing criteria are met: process
meets the definition of bag or
cartridge filtration; removal effi-
ciency established through
challenge testing that meets cri-
teria in this subpart; and chal-
lenge test shows at least 2 log
removal for bag filters and 3 log
removal for cartridge filters.
(ii) Monthly verification that 100%
of flow was filtered.
Monthly verification that 100% of
flow was filtered through both
stages.
Monthly verification that 100% of
flow was filtered.
Summary of CT values for each
day based on Table in
§141.729(b).
Monthly reporting within 10 days
following the month in which
the monitoring was conducted,
beginning on [Date 72 Months
After Date of Publication of
Final Rule in the Federal Reg-
ister].
Monthly reporting within 10 days
following the month in which
the monitoring was conducted,
beginning on [Date 72 Months
After Date of Publication of
Final Rule in the Federal Reg-
ister}.
No later than [Date 72 Months
After Date of Publication of
Final Rule in the Federal Reg-
ister].
Within 10 days following the
month in which monitoring was
conducted, beginning [Date 72
Months After Date of Publica-
tion of Final Rule in the Federal
Register].
No later than [Date 72 Months
After Date of Publication of
Final Rule in the Federal Reg-
ister].
Within 10 days following the
month in which monitoring was
conducted, beginning [Date 72
Months After Date of Publica-
tion of Final Rule in the Federal
Register],
Within 10 days following the
month in which monitoring was
conducted, beginning [Date 72
Months After Date of Publica-
tion of Final Rule in the Federal
Register].
Within 10 days following the
month in which monitoring was
conducted, beginning [Date 72
Months After Dale of Publica-
tion of Final Rule in the Federal
Register].
Within 10 days following the
month in which monitoring was
conducted, beginning [Date 72
Months After Date of Publica-
tion of Final Rule in the Federal
Register].
Monthly reporting within 10 days
following the month in which
the monitoring was conducted,
beginning on [Date 102 Months
After Date of Publication of
Final Rule in the Federal Reg-
ister].
Monthly reporting within 10 days
following the month in which
the monitoring was conducted,
beginning on [Date 102 Months
After Date of Publication of
Final Rule in the Federal Reg-
ister].
No later than [Date 102 Months
After Date of Publication of
Final Rule in the Federal Reg-
ister].
Within 10 days following the
month in which monitoring was
conducted, beginning [Date 102
Months After Date of Publica-
tion of Final Rule in the Federal
Register].
No later than [Date 102 Months
After Date of Publication of
Final Rule in the Federal Reg*
Isterj.
Within 10 days following the
month in which monitoring was
conducted, beginning [Date 102
Months After Date of Publica-
tion of Final Rule in the Federal
Register].
Within 10 days following the
month in which monitoring was
conducted, beginning [Date 102
Months After Date of Publica-
tion of Final Rule in the Federal
Register].
Within 10 days following the
month in which monitoring was
conducted, beginning [Date 102
Months After Date of Publica-
tion of Final Rule in the Federal
Register].
Within 10 days following the
month in which monitoring was
conducted, beginning [Date 102
Months After Date of Publica-
tion of Final Rule in the Federal
Register].
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Federal Register/Vol. 68, No. 154/Monday, August 11, 2003/Proposed Rules
47793
MICROBIAL TOOLBOX REPORTING REQUIREMENTS—Continued
Toolbox option
Systems must submit the fol-
lowing information
On the following schedule1—sys-
tems serving > 10,000 people
On the following schedule1—sys-
tems serving < 10,000 people
(12) Ozone
(13) UV
(14) Demonstration of performance
Summary of CT values for each
day based on Table in
§141.729(c).
(i) Validation test results dem-
onstrating operating conditions
that achieve required UV dose.
(ii) Monthly report summarizing
the percentage of water enter-
ing the distribution system that
was not treated by UV reactors
operating within validated con-
ditions for the required dose as
specified in § 141.729(d).
(i) Results from testing following a
State approved protocol.
(ii) As required by the State,
monthly verification of operation
within conditions of State ap-
proval for demonstration of per-
formance credit.
Within 10 days following the
month in which monitoring was
conducted, beginning [Date 72
Months After Date of Publica-
tion of Final Rule in the Federal
Register].
No later than [Date 72 Months
After Date of Publication of
Final Rule in the Federal Reg-
ister].
Within 10 days following the
month in which monitoring was
conducted, beginning pate 72
Months After Date of Publica-
tion of Final Rule in the Federal
Register].
No later than [Date 72 Months
After Date of Publication of
Final Rule in the Federal Reg-
ister].
Within 10 days following the
month in which monitoring was
conducted, beginning [Date 72
Months After Date of Publica-
tion of Final Rule in the Federal
Register].
Within 10 days following the
month in which monitoring was
conducted, beginning [Date 102
Months After Date of Publica-
tion of Final Rule in the Federal
Register].
No later than [Date 102 Months
After Date of Publication of
Final Rule in the Federal Reg-
ister].
Within 10 days following the
month in which monitoring was
conducted, beginning [Date 102
Months After Date of Publica-
tion of Final Rule in the Federal
Register].
No later than [Date 102 Months
After Date of Publication of
Final Rule in the Federal Reg-
ister].
Within 10 days following the
month in which monitoring was
conducted, beginning [Date 102
Months After Date of Publica-
tion of Final Rule in the Federal
Register].
1 States may allow up to an additional two years to the date when the first submittal must be completed for systems making capital
improvements.
(f) Systems must report to the State
the information associated with
disinfection profiling and benchmarking accordance with the tables in this
requirements of §§141.711 to 141.714 in paragraph.
TABLE 1.—DISINFECTION PROFILING REPORTING REQUIREMENTS FOR URGE SYSTEMS
[Serving >10,000 people]
System type
Benchmark component
Submit the following items
On the following schedule
(1) Systems required to conduct
Cyrptosporidium monitoring.
(2) Systems not required to con-
duct Cryptosporidium moni-
toring a.
(i) Characterization of disinfection
practices. See §141.713.
(ii) State review of proposed sig-
nificant changes to disinfection
practice. See §141.714.
(i) Applicability
(ii) Characterization of Disinfection
Practices.
(iii) State Review of Proposed
Changes to Disinfection Prac-
tices.
Giardia lambda and virus inactiva-
tion profiles must be on file for
State review during sanitary
survey.
Inactivation profile and benchmark
determinations.
None
None
None
No later than [Date 36 Months
After Date of Publication of
Final Rule in the Federal Reg-
ister].
Prior to significant modification of
disinfection practice.
None.
None.
None.
aSystems that provide at least 5.5 log of Cryptosporidium treatment, consistent with a Bin 4 treatment requirement, are not required to conduct
Cryptosporidium monitoring.
TABLE 2.—DISINFECTION PROFILING REPORTING REQUIREMENTS FOR SMALL SYSTEMS
[Serving < 10,000 people]
System type
Benchmark component
Submit the following items
On the following schedule
(1) Systems required to conduct
Cryptosporidium monitoring.
(i) Characterization of disinfection
practices. See §141.713.
Giardia lamblia and virus disinfec-
tion profiles must be on file for
State review during sanitary
survey.
No later than [Date 66 Months
After Date of Publication of
Final Rule in the Federal Reg-
ister].
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47794:
Federal Register/Vol. 68, No. 154/Monday, August 11, 2003/Proposed Rules
TABLE 2.—DISINFECTION PROFILING REPORTING REQUIREMENTS FOR SMALL SYSTEMS—Continued
[Serving < 10,000 people]
System type
Benchmark component
Submit the following items
On the following schedule
(2) Systems not required to con-
duct Cryptosporidium monitoring
and that exceed DBP triggers
(3) Systems not required to con-
duct Cryptosporidium monitoring
and that do not exceed DBP
triggers b'°.
(ii) State review of proposed sig-
nificant changes to disinfection
practices. See §141.714.
(i) Determination of requirement
to profile. See §141.711(b).
(ii) Characterization of disinfection
practices. See §141.713.
(iij) State review of proposed sig-
nificant changes to disinfection
practices. See §141.714.
(i) Determination of no require-
ment to profile. See
(ii) Characterization of disinfection
practices. See §141.713.
(iii) State review of proposed sig-
nificant changes to disinfection
practice. See §141. 714.
Disinfection profiles and bench-
mark determinations.
Report on TTHM and HAA5 LRAA
values from monitoring under
subpart L.
Giardia lambia and virus disinfec-
tion profiles must be on file for
State review during sanitary
survey.
Disinfection profiles and bench-
mark determinations.
Report on TTHM and HAAS LRAA
values from monitoring under
subpart L.
None
None
Prior to significant modification of
disinfection practice.
No later than [Date 42 Months
After Date of Publication of
Final Rule in the Federal Reg-
ister].
No later than [Date 54 Months
after Date of Publication of
Final Rule in the Federal Reg-
ister].
Prior to significant modification of
disinfection practice.
No later than [Date 42 Months
After Date of Publication of
Final Rule in the Federal Reg-
ister].
None.
None.
"Systems that provide at least 5.5 log of Cryptosporidium treatment, consistent with a Bin 4 treatment requirement, are not required to conduct
Cryptosporidium monitoring.
6 See § 141.702(b) to determine if Cryptosporidium monitoring is required.
cSee § 141.711(b) to determine if disinfection profiling is required based on TTHM or HAAS LRAA.
§ 141.731 Recordkeeping requirements.
(a) Systems must keep results from
monitoring required under § 141.702
until 36 months after all source water
monitoring required under this section
has been completed.
(b) Systems must keep a record of any
notification to the State that they will
not conduct source water monitoring
due to meeting the criteria of
§141.701(f)or(g).
(c] Systems required to develop
disinfection profiles under § 141.711
must keep disinfection profiles on file
for State review during sanitary surveys.
PART 142—NATIONAL PRIMARY
DRINKING WATER REGULATIONS
IMPLEMENTATION
5. 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-9and300j-ll.
6. Section 142.14 is amended by
adding paragraphs (a)(8) and (a)(9) to
read as follows:
§ 142.14 Records kept by States.
* * * * *
(a) * * *
(8) [Reserved]
(9) Any decisions made pursuant to
the provisions of part 141, subpart W of
this chapter.
(i) Results of source water E. coli and
Cryptosporidium monitoring.
(ii) Initial bin classification for each
system that currently provides filtration
or that is unfiltered and required to
install filtration, along with any change
in bin classification due to watershed
assessment during sanitary surveys or
the second round of source water
monitoring.
(iii) A determination of whether each
system that is unfiltered and meets all
the filtration avoidance criteria of
§141.71 of this chapter has a mean
source water Cryptosporidium level
above 0.01 oocysts/L, along with any
changes in this determination due to the
second round of source water
monitoring.
(iv) The treatment or control measures
that systems use to meet their
Cryptosporidium treatment
requirements under § 141.720 or
§ 141.721 of this section.
(v) A list of systems required to cover
or treat the effluent of an uncovered
finished water reservoir.
(vi) A list of systems for which the
State has waived the requirement to
cover or treat the effluent of uncovered
finished water storage facilities and
supporting documentation of the risk
mitigation plan.
*****
7. Section 142.15 is amended by
adding paragraph (c)(6) to read as
follows:
§ 142.15 Reports by States.
(c) * * *
(6) Subpart W. (i) The initial bin
classification for each system that
currently provides filtration or that is
unfiltered and required to install
filtration, along with any change in bin
classification due to watershed
assessment during sanitary surveys or
the second round of source water
monitoring.
(ii) A determination of whether each
system that is unfiltered and meets all
the filtration avoidance criteria of
§ 141.71 of this chapter has a mean
source water Cryptosporidium level
above 0.01 oocysts/L, along with any
changes in this determination due to the
second round of source water
monitoring.
*****
8. Section 142.16 is amended by
adding paragraphs (m) and (n) to read as
follows:
§142.16 Special primacy conditions.
*****
(m) [Reserved]
(n) Requirements for States to adopt
40 CFR part 141, subpart W, In addition
to the general primacy requirements
elsewhere in this part, including the
requirements that State regulations be at
least as stringent as federal
requirements, an application for
approval of a State program revision
that adopts 40 CFR part 141, subpart W,
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Federal Register/Vol. 68, No. 154/Monday, August 11, 2003/Proposed Rules
47795
must contain a description of how the
State will accomplish the following
program requirements where allowed in
State programs.
(1) Assess significant changes in the
watershed and source water as part of
the sanitary survey process and
determine appropriate follow-up action.
(2) Approve watershed control
programs for the 0.5 log watershed
control program credit in the microbial
toolbox.
(3) Approval protocols for treatment
credits under the Demonstration of
Performance toolbox option and for
alternative ozone and chlorine dioxide
CT values.
(4) Determine that a system with an
uncovered finished water reservoir has
a risk mitigation plan that is adequate
for purposes of waiving the requirement
to cover or treat the reservoir.
[FR Doc. 03-18295 Filed 8-8-03; 8:45 am]
BILLING CODE 6560-50-P
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